Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed)
Enzymes that catalyze the hydrolysis of CYCLIC AMP to form adenosine 5'-phosphate. The enzymes are widely distributed in animal tissue and control the level of intracellular cyclic AMP. Many specific enzymes classified under this heading demonstrate additional spcificity for 3',5'-cyclic IMP and CYCLIC GMP.
A cyclic nucleotide phosphodiesterase subfamily that is found predominantly in inflammatory cells and may play a role in the regulation of CELL-MEDIATED IMMUNITY. The enzyme family includes over twenty different variants that occur due to multiple ALTERNATIVE SPLICING of the mRNA of at least four different genes.
A cyclic nucleotide phosphodiesterase subfamily that is inhibited by the binding of CYCLIC GMP to an allosteric domain found on the enzyme and through phosphorylation by regulatory kinases such as PROTEIN KINASE A and PROTEIN KINASE B. The two members of this family are referred to as type 3A, and type 3B, and are each product of a distinct gene. In addition multiple enzyme variants of each subtype can be produced due to multiple alternative mRNA splicing.
A class of enzymes that catalyze the hydrolysis of one of the two ester bonds in a phosphodiester compound. EC 3.1.4.
Enzymes that catalyze the hydrolysis of cyclic GMP to yield guanosine-5'-phosphate.
A CALCIUM and CALMODULIN-dependent cyclic nucleotide phosphodiesterase subfamily. The three members of this family are referred to as type 1A, type 1B, and type 1C and are each product of a distinct gene. In addition, multiple enzyme variants of each subtype can be produced due to multiple alternative mRNA splicing. Although the type 1 enzymes are classified as 3',5'-cyclic-AMP phosphodiesterases (EC 3.1.4.17), some members of this class have additional specificity for CYCLIC GMP.
A cyclic nucleotide phosphodiesterase subfamily that is activated by the binding of CYCLIC GMP to an allosteric domain found on the enzyme. Multiple enzyme variants of this subtype can be produced due to multiple alternative mRNA splicing. The subfamily is expressed in a broad variety of tissues and may play a role in mediating cross-talk between CYCLIC GMP and CYCLIC CMP pathways. Although the type 2 enzymes are classified as 3',5'-cyclic-AMP phosphodiesterases (EC 3.1.4.17), members of this class have additional specificity for CYCLIC GMP.
Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.
Nucleoside-2',3'-cyclic phosphate nucleotidohydrolase. Enzymes that catalyze the hydrolysis of the 2'- or 3'- phosphate bonds of 2',3'-cyclic nucleotides. Also hydrolyzes nucleoside monophosphates. Includes EC 3.1.4.16 and EC 3.1.4.37. EC 3.1.4.-.
A cyclic nucleotide phosphodiesterase subfamily that is highly specific for CYCLIC GMP. It is found predominantly in vascular tissue and plays an important role in regulating VASCULAR SMOOTH MUSCLE contraction.
A phosphodiesterase 4 inhibitor with antidepressant properties.
'Purines' is a term used in medical biochemistry to refer to naturally occurring heterocyclic aromatic organic compounds, which include adenine and guanine (components of nucleotides and nucleic acids), and are formed in the body from purine bases through various metabolic processes.
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
N-(1-Oxobutyl)-cyclic 3',5'-(hydrogen phosphate)-2'-butanoate guanosine. A derivative of cyclic GMP. It has a higher resistance to extracellular and intracellular phosphodiesterase than cyclic GMP.
A cyclic nucleotide phosphodiesterase subfamily that is highly specific for CYCLIC AMP. Several isoforms of the enzyme type exist, each with its own tissue localization. The isoforms are encoded by at least two genes and are a product of multiple alternative splicing of their mRNAs.
Cyclic nucleotides are closed-chain molecules formed from nucleotides (ATP or GTP) through the action of enzymes called cyclases, functioning as second messengers in various cellular signaling pathways, with cAMP and cGMP being the most prominent members.
A potent cyclic nucleotide phosphodiesterase inhibitor; due to this action, the compound increases cyclic AMP and cyclic GMP in tissue and thereby activates CYCLIC NUCLEOTIDE-REGULATED PROTEIN KINASES
An enzyme that catalyzes the conversion of GTP to 3',5'-cyclic GMP and pyrophosphate. It also acts on ITP and dGTP. (From Enzyme Nomenclature, 1992) EC 4.6.1.2.
Compounds that specifically inhibit PHOSPHODIESTERASE 4.
Compounds that specifically inhibit PHOSPHODIESTERASE 3.
Enzymes that catalyze the cleavage of a phosphorus-oxygen bond by means other than hydrolysis or oxidation. EC 4.6.
A phosphoric diester hydrolase that removes 5'-nucleotides from the 3'-hydroxy termini of 3'-hydroxy-terminated OLIGONUCLEOTIDES. It has low activity towards POLYNUCLEOTIDES and the presence of 3'-phosphate terminus on the substrate may inhibit hydrolysis.
A group of cyclic GMP-dependent enzymes that catalyze the phosphorylation of SERINE or THREONINE residues of proteins.
A group of compounds that are derivatives of oxo-pyrrolidines. A member of this group is 2-oxo pyrrolidine, which is an intermediate in the manufacture of polyvinylpyrrolidone. (From Merck Index, 11th ed)
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
Inhibitor of phosphodiesterases.
A positive inotropic cardiotonic agent with vasodilator properties. It inhibits cAMP phosphodiesterase type 3 activity in myocardium and vascular smooth muscle. Milrinone is a derivative of amrinone and has 20-30 times the inotropic potency of amrinone.
A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.
Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.
Compounds that specifically inhibit PHOSPHODIESTERASE 5.
Systems in which an intracellular signal is generated in response to an intercellular primary messenger such as a hormone or neurotransmitter. They are intermediate signals in cellular processes such as metabolism, secretion, contraction, phototransduction, and cell growth. Examples of second messenger systems are the adenyl cyclase-cyclic AMP system, the phosphatidylinositol diphosphate-inositol triphosphate system, and the cyclic GMP system.
The rate dynamics in chemical or physical systems.
An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.
A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.
A group of enzymes that are dependent on CYCLIC AMP and catalyze the phosphorylation of SERINE or THREONINE residues on proteins. Included under this category are two cyclic-AMP-dependent protein kinase subtypes, each of which is defined by its subunit composition.
A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3',5'-CYCLIC NUCLEOTIDE PHOSPHODIESTERASE that degrades CYCLIC AMP thus potentiates the actions of agents that act through ADENYLYL CYCLASES and cyclic AMP.
'Cyclic P-Oxides' is a term used in medicinal chemistry to describe a class of organic compounds where a cyclic structure contains at least one peroxide bond (-O-O-), characterized by their unique chemical properties and potential therapeutic applications, particularly as anti-cancer or antiviral agents.
A group of indole-indoline dimers which are ALKALOIDS obtained from the VINCA genus of plants. They inhibit polymerization of TUBULIN into MICROTUBULES thus blocking spindle formation and arresting cells in METAPHASE. They are some of the most useful ANTINEOPLASTIC AGENTS.
A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.
An enzyme of the lyase class that catalyzes the formation of CYCLIC AMP and pyrophosphate from ATP. EC 4.6.1.1.
A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Potent activator of the adenylate cyclase system and the biosynthesis of cyclic AMP. From the plant COLEUS FORSKOHLII. Has antihypertensive, positive inotropic, platelet aggregation inhibitory, and smooth muscle relaxant activities; also lowers intraocular pressure and promotes release of hormones from the pituitary gland.
A long-acting derivative of cyclic AMP. It is an activator of cyclic AMP-dependent protein kinase, but resistant to degradation by cyclic AMP phosphodiesterase.
A component of PHOSPHATIDYLCHOLINES or LECITHINS, in which the two hydroxy groups of GLYCEROL are esterified with fatty acids. (From Stedman, 26th ed) It counteracts the effects of urea on enzymes and other macromolecules.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.
Oxadiazoles are heterocyclic organic compounds consisting of a five-membered ring containing two carbon atoms, one nitrogen atom, and two oxygen atoms (one as a part of the oxadiazole ring and the other as a substituent or part of a larger molecule), which can exist in various isomeric forms and are known for their versatile biological activities, including anti-inflammatory, antiviral, antibacterial, and antitumor properties.
The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.
The portion of a retinal rod cell situated between the ROD INNER SEGMENT and the RETINAL PIGMENT EPITHELIUM. It contains a stack of photosensitive disk membranes laden with RHODOPSIN.
Purine bases found in body tissues and fluids and in some plants.
The process of cleaving a chemical compound by the addition of a molecule of water.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A group of enzymes within the class EC 3.6.1.- that catalyze the hydrolysis of diphosphate bonds, chiefly in nucleoside di- and triphosphates. They may liberate either a mono- or diphosphate. EC 3.6.1.-.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
That phase of a muscle twitch during which a muscle returns to a resting position.
Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
A cyclic nucleotide derivative that mimics the action of endogenous CYCLIC AMP and is capable of permeating the cell membrane. It has vasodilator properties and is used as a cardiac stimulant. (From Merck Index, 11th ed)
Sulfones are a class of organic compounds containing the functional group with a sulfur atom bonded to two oxygen atoms and another organic group, widely used in pharmaceuticals, particularly for the treatment of bacterial infections, leprosy, and certain types of cancer.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The nonstriated involuntary muscle tissue of blood vessels.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
3-Mercapto-D-valine. The most characteristic degradation product of the penicillin antibiotics. It is used as an antirheumatic and as a chelating agent in Wilson's disease.
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
A structurally-diverse family of intracellular-signaling adaptor proteins that selectively tether specific protein kinase A subtypes to distinct subcellular sites. They play a role in focusing the PROTEIN KINASE A activity toward relevant substrates. Over fifty members of this family exist, most of which bind specifically to regulatory subunits of CYCLIC AMP-DEPENDENT PROTEIN KINASE TYPE II such as CAMP PROTEIN KINASE RIIALPHA or CAMP PROTEIN KINASE RIIBETA.
A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
Drugs used to cause dilation of the blood vessels.
Cell surface proteins that bind ATRIAL NATRIURETIC FACTOR with high affinity and trigger intracellular changes influencing the behavior of cells. They contain intrinsic guanylyl cyclase activity.
A genus of protozoa, formerly also considered a fungus. Its natural habitat is decaying forest leaves, where it feeds on bacteria. D. discoideum is the best-known species and is widely used in biomedical research.
The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.
A sulfur-containing alkyl thionitrite that is one of the NITRIC OXIDE DONORS.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)
An essential amino acid that is physiologically active in the L-form.
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
A group of pyrido-indole compounds. Included are any points of fusion of pyridine with the five-membered ring of indole and any derivatives of these compounds. These are similar to CARBAZOLES which are benzo-indoles.
Quinoxalines are heterocyclic organic compounds consisting of a benzene fused to a pyrazine ring, which have been studied for their potential antibacterial, antifungal, and anticancer properties.
A group of derivatives of naphthyridine carboxylic acid, quinoline carboxylic acid, or NALIDIXIC ACID.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
A morpholinyl sydnone imine ethyl ester, having a nitrogen in place of the keto oxygen. It acts as NITRIC OXIDE DONORS and is a vasodilator that has been used in ANGINA PECTORIS.
An enzyme that catalyzes the reversible oxidation of inosine 5'-phosphate (IMP) to guanosine 5'-phosphate (GMP) in the presence of AMMONIA and NADP+. This enzyme was formerly classified as EC 1.6.6.8.
A diverse group of agents, with unique chemical structures and biochemical requirements, which generate NITRIC OXIDE. These compounds have been used in the treatment of cardiovascular diseases and the management of acute myocardial infarction, acute and chronic congestive heart failure, and surgical control of blood pressure. (Adv Pharmacol 1995;34:361-81)
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752)
Adenine nucleotides are molecules that consist of an adenine base attached to a ribose sugar and one, two, or three phosphate groups, including adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), which play crucial roles in energy transfer and signaling processes within cells.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A cyclic GMP-dependent protein kinase subtype that is expressed in SMOOTH MUSCLE tissues and plays a role in regulation of smooth muscle contraction. Two isoforms, PKGIalpha and PKGIbeta, of the type I protein kinase exist due to alternative splicing of its mRNA.
Piperazines are a class of heterocyclic organic compounds containing a seven-membered ring with two nitrogen atoms at positions 1 and 4, often used in pharmaceuticals as smooth muscle relaxants, antipsychotics, antidepressants, and antihistamines, but can also be found as recreational drugs with stimulant and entactogen properties.
Quinolines substituted in any position by one or more amino groups.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A group of compounds which consist of a nucleotide molecule to which an additional nucleoside is attached through the phosphate molecule(s). The nucleotide can contain any number of phosphates.
An inhibitor of nitric oxide synthetase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. (Neurochem Res 1995:200(4):451-6)
Nitroso compounds are organic or inorganic substances containing the nitroso functional group, which consists of a nitrogen atom bonded to an oxygen atom through a single covalent bond, often abbreviated as -NO.
Peptides that regulate the WATER-ELECTROLYTE BALANCE in the body, also known as natriuretic peptide hormones. Several have been sequenced (ATRIAL NATRIURETIC FACTOR; BRAIN NATRIURETIC PEPTIDE; C-TYPE NATRIURETIC PEPTIDE).
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
A cyclic nucleotide phosphodiesterase subfamily that is highly specific for CYCLIC GMP. It is found predominantly in the outer segment PHOTORECEPTOR CELLS of the RETINA. It is comprised of two catalytic subunits, referred to as alpha and beta, that form a dimer. In addition two regulatory subunits, referred to as gamma and delta, modulate the activity and localization of the enzyme.
A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.
Established cell cultures that have the potential to propagate indefinitely.
A competitive inhibitor of nitric oxide synthetase.
Proteins found in any species of bacterium.
A PEPTIDE of 22 amino acids, derived mainly from cells of VASCULAR ENDOTHELIUM. It is also found in the BRAIN, major endocrine glands, and other tissues. It shares structural homology with ATRIAL NATRIURETIC FACTOR. It has vasorelaxant activity thus is important in the regulation of vascular tone and blood flow. Several high molecular weight forms containing the 22 amino acids have been identified.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A sulfur-containing alkyl thionitrite that is one of the NITRIC OXIDE DONORS.
Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Contractile activity of the MYOCARDIUM.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
The sum of the weight of all the atoms in a molecule.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
Elements of limited time intervals, contributing to particular results or situations.
A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.
A serotonin uptake inhibitor that is used as an antidepressive agent. It has been shown to be effective in patients with major depressive disorders and other subsets of depressive disorders. It is generally more useful in depressive disorders associated with insomnia and anxiety. This drug does not aggravate psychotic symptoms in patients with schizophrenia or schizoaffective disorders. (From AMA Drug Evaluations Annual, 1994, p309)
The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING.
The conformation, properties, reaction processes, and the properties of the reactions of carbon compounds.
One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.
Indazoles are heterocyclic aromatic organic compounds that consist of a benzene ring fused with a pyrazole ring, and they are used as building blocks in the synthesis of various pharmaceutical drugs.
A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.
The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.
The main trunk of the systemic arteries.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A species of the true toads, Bufonidae, becoming fairly common in the southern United States and almost pantropical. The secretions from the skin glands of this species are very toxic to animals.
Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.
A nonapeptide messenger that is enzymatically produced from KALLIDIN in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from MAST CELLS during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Proteins prepared by recombinant DNA technology.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Proteins obtained from ESCHERICHIA COLI.
A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate. EC 3.1.3.
Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
Guanine nucleotides are cyclic or linear molecules that consist of a guanine base, a pentose sugar (ribose in the cyclic form, deoxyribose in the linear form), and one or more phosphate groups, playing crucial roles in signal transduction, protein synthesis, and regulation of enzymatic activities.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
Inosine 5'-(tetrahydrogen triphosphate). An inosine nucleotide containing three phosphate groups esterified to the sugar moiety. Synonym: IRPPP.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.
Nucleotides in which the base moiety is substituted with one or more sulfur atoms.
Encrustations, formed from microbes (bacteria, algae, fungi, plankton, or protozoa) embedding in extracellular polymers, that adhere to surfaces such as teeth (DENTAL DEPOSITS); PROSTHESES AND IMPLANTS; and catheters. Biofilms are prevented from forming by treating surfaces with DENTIFRICES; DISINFECTANTS; ANTI-INFECTIVE AGENTS; and antifouling agents.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
A heterotrimeric GTP-binding protein that mediates the light activation signal from photolyzed rhodopsin to cyclic GMP phosphodiesterase and is pivotal in the visual excitation process. Activation of rhodopsin on the outer membrane of rod and cone cells causes GTP to bind to transducin followed by dissociation of the alpha subunit-GTP complex from the beta/gamma subunits of transducin. The alpha subunit-GTP complex activates the cyclic GMP phosphodiesterase which catalyzes the hydrolysis of cyclic GMP to 5'-GMP. This leads to closure of the sodium and calcium channels and therefore hyperpolarization of the rod cells. EC 3.6.1.-.
Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and nonexcitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites.
A class of enzymes that catalyze oxidation-reduction reactions of amino acids.
A potassium-channel opening vasodilator that has been investigated in the management of hypertension. It has also been tried in patients with asthma. (Martindale, The Extra Pharmacopoeia, 30th ed, p352)
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.
A group of compounds that are derivatives of beta-methylacetylcholine (methacholine).
The external reproductive organ of males. It is composed of a mass of erectile tissue enclosed in three cylindrical fibrous compartments. Two of the three compartments, the corpus cavernosa, are placed side-by-side along the upper part of the organ. The third compartment below, the corpus spongiosum, houses the urethra.
Mixtures of closely related hypotensive alkaloids from Veratrum album (Liliaceae). They have been used in the treatment of hypertension but have largely been replaced by drugs with fewer adverse effects.
An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.

Cyclic guanosine monophosphate (cGMP) is a important second messenger molecule that plays a crucial role in various biological processes within the human body. It is synthesized from guanosine triphosphate (GTP) by the enzyme guanylyl cyclase.

Cyclic GMP is involved in regulating diverse physiological functions, such as smooth muscle relaxation, cardiovascular function, and neurotransmission. It also plays a role in modulating immune responses and cellular growth and differentiation.

In the medical field, changes in cGMP levels or dysregulation of cGMP-dependent pathways have been implicated in various disease states, including pulmonary hypertension, heart failure, erectile dysfunction, and glaucoma. Therefore, pharmacological agents that target cGMP signaling are being developed as potential therapeutic options for these conditions.

3',5'-Cyclic-AMP (cyclic adenosine monophosphate) phosphodiesterases are a group of enzymes that catalyze the breakdown of cyclic AMP to 5'-AMP. These enzymes play a crucial role in regulating the levels of intracellular second messengers, such as cyclic AMP, which are involved in various cellular signaling pathways.

There are several subtypes of phosphodiesterases (PDEs) that specifically target cyclic AMP, including PDE1, PDE2, PDE3, PDE4, PDE7, PDE8, and PDE10. Each subtype has distinct regulatory and catalytic properties, allowing for specific regulation of cyclic AMP levels in different cellular compartments and signaling pathways.

Inhibition of these enzymes can lead to an increase in intracellular cyclic AMP levels, which can have therapeutic effects in various diseases, such as cardiovascular disease, pulmonary hypertension, and central nervous system disorders. Therefore, PDE inhibitors are a valuable class of drugs for the treatment of these conditions.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that regulate intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are important second messengers involved in various cellular processes.

Type 4 phosphodiesterases (PDE4) specifically hydrolyze cAMP and play a crucial role in regulating its intracellular concentration. PDE4 is widely expressed in many tissues, including the brain, heart, lungs, and immune system. It is involved in various physiological functions such as smooth muscle relaxation, neurotransmission, and inflammation.

PDE4 inhibitors have been developed as therapeutic agents for a variety of diseases, including asthma, chronic obstructive pulmonary disease (COPD), and depression. These drugs work by increasing intracellular cAMP levels, which can lead to bronchodilation, anti-inflammatory effects, and mood regulation. However, PDE4 inhibitors may also have side effects such as nausea, vomiting, and diarrhea, which limit their clinical use.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that regulate intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are important second messengers involved in various cellular processes.

Type 3 PDEs, also known as PDE3, are a subtype of this enzyme family that specifically hydrolyze cAMP and cGMP. They are widely expressed in various tissues, including the heart, vascular smooth muscle, platelets, and adipose tissue.

PDE3 plays a crucial role in regulating cardiovascular function, lipolysis, and insulin sensitivity. Inhibition of PDE3 has been shown to have positive inotropic and vasodilatory effects, making it a potential therapeutic target for the treatment of heart failure and pulmonary hypertension. Additionally, PDE3 inhibitors have been used as antiplatelet agents to prevent thrombosis.

There are two isoforms of PDE3, PDE3A and PDE3B, which differ in their tissue distribution and regulatory mechanisms. PDE3A is primarily expressed in the heart and vascular smooth muscle, while PDE3B is found in adipose tissue and insulin-sensitive cells.

Overall, the regulation of intracellular cAMP and cGMP levels by PDE3 plays a critical role in maintaining cardiovascular function, metabolism, and hemostasis.

Phosphoric diester hydrolases are a class of enzymes that catalyze the hydrolysis of phosphoric diester bonds. These enzymes are also known as phosphatases or nucleotidases. They play important roles in various biological processes, such as signal transduction, metabolism, and regulation of cellular activities.

Phosphoric diester hydrolases can be further classified into several subclasses based on their substrate specificity and catalytic mechanism. For example, alkaline phosphatases (ALPs) are a group of phosphoric diester hydrolases that preferentially hydrolyze phosphomonoester bonds in a variety of organic molecules, releasing phosphate ions and alcohols. On the other hand, nucleotidases are a subclass of phosphoric diester hydrolases that specifically hydrolyze the phosphodiester bonds in nucleotides, releasing nucleosides and phosphate ions.

Overall, phosphoric diester hydrolases are essential for maintaining the balance of various cellular processes by regulating the levels of phosphorylated molecules and nucleotides.

3',5'-Cyclic guanosine monophosphate (cGMP) phosphodiesterases are a group of enzymes that play a role in regulating the levels of cGMP, an important intracellular signaling molecule involved in various biological processes. These enzymes catalyze the hydrolysis of cGMP to 5'-GMP, thereby terminating cGMP-mediated signals within cells.

There are several isoforms of cGMP phosphodiesterases, which differ in their regulatory properties, substrate specificity, and cellular distribution. These enzymes can be activated or inhibited by various factors, including drugs, hormones, and neurotransmitters, and play a crucial role in modulating the activity of cGMP-dependent signaling pathways in different tissues and organs.

Dysregulation of cGMP phosphodiesterase activity has been implicated in various diseases, including cardiovascular disorders, pulmonary hypertension, neurodegenerative diseases, and cancer. Therefore, these enzymes are considered important targets for the development of novel therapeutic strategies for the treatment of these conditions.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that regulate intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are important second messengers involved in various cellular processes.

Type 1 PDEs (PDE1A, PDE1B, PDE1C) are calcium/calmodulin-regulated enzymes that hydrolyze both cAMP and cGMP with similar catalytic efficiency. They play a crucial role in the regulation of vascular smooth muscle contraction, platelet aggregation, and neuronal excitability.

Dysregulation of PDE1 activity has been implicated in various pathological conditions, including hypertension, cardiovascular diseases, and neurological disorders. Therefore, PDE1 inhibitors have emerged as potential therapeutic agents for the treatment of these conditions.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that regulate intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are important second messengers involved in various cellular processes.

Type 2 phosphodiesterases (PDE2) are a subtype of this family that specifically hydrolyze both cAMP and cGMP to their respective 5'-monophosphates, thereby reducing their intracellular concentrations. PDE2 enzymes are widely expressed in various tissues, including the brain, heart, and vasculature, where they play important roles in regulating signal transduction pathways.

PDE2 enzymes are composed of two regulatory subunits and one catalytic subunit, which contains the active site for phosphodiesterase activity. The regulatory subunits can bind to cGMP, leading to an increase in PDE2 activity towards both cAMP and cGMP. This unique property of PDE2 enzymes allows them to act as coincidence detectors that integrate signals from multiple second messenger pathways.

Inhibition of PDE2 has been shown to have therapeutic potential in various diseases, including cardiovascular disease, neurodegenerative disorders, and cancer. For example, PDE2 inhibitors have been shown to improve cardiac function, protect against ischemic injury, and enhance cognitive function in animal models. However, further research is needed to fully understand the therapeutic potential of PDE2 inhibition and its potential side effects.

Phosphodiesterase inhibitors (PDE inhibitors) are a class of drugs that work by blocking the action of phosphodiesterase enzymes, which are responsible for breaking down cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), two crucial intracellular signaling molecules.

By inhibiting these enzymes, PDE inhibitors increase the concentration of cAMP and cGMP in the cells, leading to a variety of effects depending on the specific type of PDE enzyme that is inhibited. These drugs have been used in the treatment of various medical conditions such as erectile dysfunction, pulmonary arterial hypertension, and heart failure.

Examples of PDE inhibitors include sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) for erectile dysfunction, and iloprost, treprostinil, and sildenafil for pulmonary arterial hypertension. It's important to note that different PDE inhibitors have varying levels of selectivity for specific PDE isoforms, which can result in different therapeutic effects and side effect profiles.

2,3'-Cyclic-nucleotide phosphodiesterases (PDEs) are a subclass of enzymes that belong to the family of phosphodiesterases. These enzymes are responsible for the hydrolysis of 2,3'-cyclic nucleotides, which are cyclic forms of nucleotides that act as second messengers in various cellular signaling pathways.

The two primary types of 2,3'-cyclic nucleotides are 2',3'-cGMP and 2',3'-cAMP, which are produced by the action of certain enzymes on their respective precursors, guanosine triphosphate (GTP) and adenosine triphosphate (ATP). These cyclic nucleotides play important roles in regulating various cellular processes, including metabolism, gene expression, and ion channel activity.

2,3'-Cyclic-nucleotide phosphodiesterases catalyze the hydrolysis of these cyclic nucleotides to their corresponding 5'-monophosphates, thereby terminating their signaling activity. There are several isoforms of 2,3'-cyclic-nucleotide PDEs that have been identified, each with distinct substrate specificities and regulatory properties.

Dysregulation of 2,3'-cyclic-nucleotide PDE activity has been implicated in various diseases, including cancer, cardiovascular disease, and neurological disorders. Therefore, these enzymes have emerged as important targets for the development of therapeutic agents that can modulate their activity and restore normal cellular function.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that regulate intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) by catalyzing the hydrolysis of these second messenger molecules to their inactive forms. These signaling molecules play crucial roles in various cellular processes, including smooth muscle relaxation, cardiac contractility, and neurotransmission.

Type 5 PDEs (PDE5) are a subtype of this enzyme family that specifically hydrolyze cGMP. They are widely distributed in various tissues, including vascular smooth muscle, lung, platelets, and the corpus cavernosum of the penis. PDE5 is particularly important in the regulation of smooth muscle relaxation in the corpus cavernosum, where it plays a key role in the physiological response to sexual stimulation leading to penile erection.

PDE5 inhibitors, such as sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra), are commonly used to treat erectile dysfunction by increasing cGMP levels in the corpus cavernosum, thereby promoting smooth muscle relaxation and enhancing blood flow to the penis. These medications have also been investigated for their potential therapeutic benefits in other conditions, such as pulmonary arterial hypertension and benign prostatic hyperplasia.

Rolipram is not a medical term per se, but it is the name of a pharmaceutical compound. Rolipram is a selective inhibitor of phosphodiesterase-4 (PDE4), an enzyme that plays a role in regulating the body's inflammatory response and is involved in various cellular signaling pathways.

Rolipram has been investigated as a potential therapeutic agent for several medical conditions, including depression, asthma, chronic obstructive pulmonary disease (COPD), and Alzheimer's disease. However, its development as a drug has been hindered by issues related to its pharmacokinetics, such as poor bioavailability and a short half-life, as well as side effects like nausea and emesis.

Therefore, while Rolipram is an important compound in the field of pharmacology and has contributed significantly to our understanding of PDE4's role in various physiological processes, it is not typically used as a medical term to describe a specific disease or condition.

I'm sorry for any confusion, but "Purinones" is not a recognized term in medical terminology. It seems there might be a spelling mistake or a misunderstanding of the term. If you meant "purines," I can provide a definition for that. Purines are heterocyclic aromatic organic compounds that form the basis of several important biomolecules, such as nucleotides and their derivatives found in DNA and RNA. If you had something different in mind, please provide clarification so I can give you an accurate and helpful response.

Cyclic adenosine monophosphate (cAMP) is a key secondary messenger in many biological processes, including the regulation of metabolism, gene expression, and cellular excitability. It is synthesized from adenosine triphosphate (ATP) by the enzyme adenylyl cyclase and is degraded by the enzyme phosphodiesterase.

In the body, cAMP plays a crucial role in mediating the effects of hormones and neurotransmitters on target cells. For example, when a hormone binds to its receptor on the surface of a cell, it can activate a G protein, which in turn activates adenylyl cyclase to produce cAMP. The increased levels of cAMP then activate various effector proteins, such as protein kinases, which go on to regulate various cellular processes.

Overall, the regulation of cAMP levels is critical for maintaining proper cellular function and homeostasis, and abnormalities in cAMP signaling have been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Dibutyryl cyclic guanosine monophosphate (cAMP) is a chemically modified form of the second messenger molecule, cyclic GMP (guanosine monophosphate). The addition of butyryl groups to the cyclic GMP molecule makes it more lipid-soluble and allows for easier passage through cell membranes. This compound is often used in research to activate protein kinases and study the effects of increased intracellular levels of cyclic GMP, which plays a role in various cellular processes such as smooth muscle relaxation, regulation of ion channels, and inhibition of platelet aggregation.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that play a crucial role in regulating intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are important second messengers involved in various cellular processes.

Type 7 PDEs, also known as PDE7, is a subtype of the PDE family that specifically hydrolyzes cAMP. PDE7 is primarily expressed in hematopoietic cells, including T lymphocytes, monocytes, and natural killer (NK) cells, and plays a critical role in regulating immune cell functions.

PDE7 has two isoforms, PDE7A and PDE7B, which are encoded by different genes but share similar structures and functions. These isoforms are differentially expressed in various tissues and cells, with PDE7A being more abundant in T lymphocytes and monocytes, while PDE7B is predominantly expressed in NK cells.

Inhibition of PDE7 has been shown to enhance cAMP signaling and modulate immune cell functions, suggesting that PDE7 inhibitors may have therapeutic potential for the treatment of various inflammatory and autoimmune diseases, as well as cancer.

Cyclic nucleotides are formed by the intramolecular phosphoester bond between the phosphate group and the hydroxyl group at the 3'-carbon atom of the ribose sugar in a nucleotide. This creates a cyclic structure, specifically a cyclic phosphate. The most common cyclic nucleotides are cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). These molecules function as second messengers in cells, playing crucial roles in various cellular signaling pathways related to metabolism, gene expression, and cell differentiation. The levels of cAMP and cGMP are tightly regulated by the activities of enzymes such as adenylate cyclase and guanylate cyclase for their synthesis, and phosphodiesterases for their degradation.

1-Methyl-3-isobutylxanthine is a chemical compound that belongs to the class of xanthines. It is a methylated derivative of xanthine and is commonly found in some types of tea, coffee, and chocolate. This compound acts as a non-selective phosphodiesterase inhibitor, which means it can increase the levels of intracellular cyclic AMP (cAMP) by preventing its breakdown.

In medical terms, 1-Methyl-3-isobutylxanthine is often used as a bronchodilator and a stimulant of central nervous system. It is also known to have diuretic properties. This compound is sometimes used in the treatment of asthma, COPD (chronic obstructive pulmonary disease), and other respiratory disorders.

It's important to note that 1-Methyl-3-isobutylxanthine can have side effects, including increased heart rate, blood pressure, and anxiety. It should be used under the supervision of a medical professional and its use should be carefully monitored to avoid potential adverse reactions.

Guanylate cyclase is an enzyme that catalyzes the conversion of guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP), which acts as a second messenger in various cellular signaling pathways. There are two main types of guanylate cyclases: soluble and membrane-bound. Soluble guanylate cyclase is activated by nitric oxide, while membrane-bound guanylate cyclase can be activated by natriuretic peptides. The increased levels of cGMP produced by guanylate cyclase can lead to a variety of cellular responses, including smooth muscle relaxation, neurotransmitter release, and regulation of ion channels. Dysregulation of guanylate cyclase activity has been implicated in several diseases, such as hypertension, heart failure, and cancer.

Phosphodiesterase 4 inhibitors (PDE4 inhibitors) are a class of drugs that work by increasing the levels of cyclic adenosine monophosphate (cAMP) in cells. They do this by blocking the phosphodiesterase 4 enzyme, which is responsible for breaking down cAMP.

Cyclic AMP is an important intracellular signaling molecule that plays a role in various physiological processes, including inflammation and immune response. By increasing cAMP levels, PDE4 inhibitors can help to reduce inflammation and modulate the immune system.

PDE4 inhibitors have been studied for their potential therapeutic benefits in a range of conditions, including asthma, COPD, psoriasis, atopic dermatitis, and depression. Some examples of PDE4 inhibitors include roflumilast, apremilast, crisaborole, and ditropan.

It's important to note that while PDE4 inhibitors have shown promise in clinical trials, they can also have side effects, such as gastrointestinal symptoms, headache, and dizziness. Additionally, their long-term safety and efficacy are still being studied.

Phosphodiesterase 3 (PDE3) inhibitors are a class of medications that work by blocking the enzyme phosphodiesterase 3, which is responsible for breaking down cyclic adenosine monophosphate (cAMP) in the body. cAMP is a secondary messenger involved in various cellular processes such as regulation of heart function, vascular smooth muscle relaxation, and metabolism.

By inhibiting PDE3, these medications increase the levels of cAMP in the body, leading to vasodilation (relaxation of blood vessels), positive inotropic effects (improvement of heart contractility), and increased lipolysis (breakdown of fats). As a result, PDE3 inhibitors are used in the treatment of conditions such as heart failure, pulmonary hypertension, and peripheral vascular disease.

Examples of PDE3 inhibitors include cilostazol, milrinone, and enoximone.

Phosphorus-Oxygen Lyases are a class of enzymes that catalyze the breakdown of a substrate containing a phosphorus-oxygen bond, releasing a phosphate group and forming a new double bond in the process. This reaction is typically represented by the general formula:

Substrate-P-O + A acceptor ------> Substrate-O=A + P\_i

where "Substrate-P-O" represents the phosphorus-oxygen bond in the substrate, "A acceptor" is the molecule that accepts the phosphate group, and "P\_i" denotes inorganic phosphate. These enzymes play important roles in various biological processes, such as signal transduction, energy metabolism, and biosynthesis.

Examples of Phosphorus-Oxygen Lyases include:

1. Phospholipase D - catalyzes the hydrolysis of phosphatidylcholine to produce phosphatidic acid and choline.
2. ATP sulfurylase - catalyzes the formation of adenosine 5'-phosphosulfate (APS) from ATP and sulfate, which is an important intermediate in the biosynthesis of sulfur-containing amino acids.
3. Inositol polyphosphate 1-phosphatase - catalyzes the dephosphorylation of inositol polyphosphates, which are involved in intracellular signaling pathways.
4. UDP-glucose pyrophosphorylase - catalyzes the reversible conversion of UDP-glucose and pyrophosphate to glucose-1-phosphate and UTP, playing a crucial role in carbohydrate metabolism.

It is important to note that Phosphorus-Oxygen Lyases are distinct from Phosphoric Monoester Hydrolases, which also catalyze the hydrolysis of phosphorus-oxygen bonds but do not form new double bonds in the process.

Phosphodiesterase I (PDE1) is an enzyme that belongs to the family of phosphodiesterase enzymes, which are responsible for breaking down cyclic nucleotides, such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), into their inactive forms. These cyclic nucleotides act as second messengers in various cellular signaling pathways, and their levels are tightly regulated by the balance between synthesis and degradation by enzymes like PDE1.

PDE1 is further classified into three subtypes: PDE1A, PDE1B, and PDE1C. These subtypes have different expression patterns and functions in various tissues and organs. For example, PDE1 is found in the brain, heart, smooth muscle, and other tissues, where it plays a role in regulating vascular tone, neurotransmission, and other physiological processes.

Inhibition of PDE1 has been explored as a potential therapeutic strategy for various conditions, including cardiovascular diseases, neurological disorders, and erectile dysfunction. However, the development of selective and specific PDE1 inhibitors has proven to be challenging due to the high degree of homology among different PDE subtypes.

Cyclic guanosine monophosphate (cGMP)-dependent protein kinases (PKGs) are a type of enzyme that add phosphate groups to other proteins, thereby modifying their function. These kinases are activated by cGMP, which is a second messenger molecule that helps transmit signals within cells. PKGs play important roles in various cellular processes, including smooth muscle relaxation, platelet aggregation, and cardiac contractility. They have been implicated in the regulation of a number of physiological functions, such as blood flow, inflammation, and learning and memory. There are two main isoforms of cGMP-dependent protein kinases, PKG I and PKG II, which differ in their tissue distribution, regulatory properties, and substrate specificity.

Pyrrolidinones are a class of organic compounds that contain a pyrrolidinone ring, which is a five-membered ring containing four carbon atoms and one nitrogen atom. The nitrogen atom is part of an amide functional group, which consists of a carbonyl (C=O) group bonded to a nitrogen atom.

Pyrrolidinones are commonly found in various natural and synthetic compounds, including pharmaceuticals, agrochemicals, and materials. They exhibit a wide range of biological activities, such as anti-inflammatory, antiviral, and anticancer properties. Some well-known drugs that contain pyrrolidinone rings include the pain reliever tramadol, the muscle relaxant cyclobenzaprine, and the antipsychotic aripiprazole.

Pyrrolidinones can be synthesized through various chemical reactions, such as the cyclization of γ-amino acids or the reaction of α-amino acids with isocyanates. The unique structure and reactivity of pyrrolidinones make them valuable intermediates in organic synthesis and drug discovery.

Nitric oxide (NO) is a molecule made up of one nitrogen atom and one oxygen atom. In the body, it is a crucial signaling molecule involved in various physiological processes such as vasodilation, immune response, neurotransmission, and inhibition of platelet aggregation. It is produced naturally by the enzyme nitric oxide synthase (NOS) from the amino acid L-arginine. Inhaled nitric oxide is used medically to treat pulmonary hypertension in newborns and adults, as it helps to relax and widen blood vessels, improving oxygenation and blood flow.

Milrinone is a type of medication known as an inotrope and vasodilator. It works by increasing the force of heart muscle contractions and relaxing the blood vessels, which leads to improved pumping ability of the heart and increased blood flow. Milrinone is primarily used in the treatment of heart failure, either in the hospital setting or after discharge, to improve symptoms and help the heart work more efficiently. It is given intravenously (through an IV) and its effects are closely monitored by healthcare professionals due to the potential for serious side effects such as irregular heart rhythms.

Methylene Blue is a heterocyclic aromatic organic compound with the molecular formula C16H18ClN3S. It is primarily used as a medication, but can also be used as a dye or as a chemical reagent. As a medication, it is used in the treatment of methemoglobinemia (a condition where an abnormal amount of methemoglobin is present in the blood), as well as in some forms of poisoning and infections. It works by acting as a reducing agent, converting methemoglobin back to hemoglobin, which is the form of the protein that is responsible for carrying oxygen in the blood. Methylene Blue has also been used off-label for other conditions, such as vasculitis and Alzheimer's disease, although its effectiveness for these uses is not well established.

It is important to note that Methylene Blue should be used with caution, as it can cause serious side effects in some people, particularly those with kidney or liver problems, or those who are taking certain medications. It is also important to follow the instructions of a healthcare provider when using this medication, as improper use can lead to toxicity.

Isoenzymes, also known as isoforms, are multiple forms of an enzyme that catalyze the same chemical reaction but differ in their amino acid sequence, structure, and/or kinetic properties. They are encoded by different genes or alternative splicing of the same gene. Isoenzymes can be found in various tissues and organs, and they play a crucial role in biological processes such as metabolism, detoxification, and cell signaling. Measurement of isoenzyme levels in body fluids (such as blood) can provide valuable diagnostic information for certain medical conditions, including tissue damage, inflammation, and various diseases.

Phosphodiesterase 5 (PDE5) inhibitors are a class of medications that work by blocking the phosphodiesterase enzyme, specifically PDE5, which is found in the smooth muscle cells lining the blood vessels of the penis. By inhibiting this enzyme, PDE5 inhibitors increase the levels of cyclic guanosine monophosphate (cGMP), a molecule that relaxes these smooth muscles and allows for increased blood flow into the corpus cavernosum of the penis, leading to an erection.

PDE5 inhibitors are commonly used in the treatment of erectile dysfunction (ED) and include medications such as sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra). These medications are usually taken orally, and their effects can last for several hours. It is important to note that PDE5 inhibitors only work in the presence of sexual stimulation, and they do not increase sexual desire or arousal on their own.

In addition to their use in ED, PDE5 inhibitors have also been shown to be effective in the treatment of pulmonary arterial hypertension (PAH) by relaxing the smooth muscle cells in the blood vessels of the lungs and reducing the workload on the heart.

Second messenger systems are a type of intracellular signaling pathway that allows cells to respond to external signals, such as hormones and neurotransmitters. When an extracellular signal binds to a specific receptor on the cell membrane, it activates a G-protein or an enzyme associated with the receptor. This activation leads to the production of a second messenger molecule inside the cell, which then propagates the signal and triggers various intracellular responses.

Examples of second messengers include cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), inositol trisphosphate (IP3), diacylglycerol (DAG), and calcium ions (Ca2+). These second messengers activate or inhibit various downstream effectors, such as protein kinases, ion channels, and gene transcription factors, leading to changes in cellular functions, such as metabolism, gene expression, cell growth, differentiation, and apoptosis.

Second messenger systems play crucial roles in many physiological processes, including sensory perception, neurotransmission, hormonal regulation, immune response, and development. Dysregulation of these systems can contribute to various diseases, such as cancer, diabetes, cardiovascular disease, and neurological disorders.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Papaverine is defined as a smooth muscle relaxant and a non-narcotic alkaloid derived from the opium poppy. It works by blocking the phosphodiesterase enzyme, leading to an increase in cyclic adenosine monophosphate (cAMP) levels within the cells, which in turn results in muscle relaxation.

It is used medically for its vasodilatory effects to treat conditions such as cerebral or peripheral vascular spasms and occlusive diseases, Raynaud's phenomenon, and priapism. Papaverine can also be used as an anti-arrhythmic agent in the management of certain types of cardiac arrhythmias.

It is important to note that papaverine has a narrow therapeutic index, and its use should be closely monitored due to the potential for adverse effects such as hypotension, reflex tachycardia, and gastrointestinal disturbances.

nitroprusside (ni-troe-rus-ide)

A rapid-acting vasodilator used in the management of severe hypertension, acute heart failure, and to reduce afterload in patients undergoing cardiac surgery. It is a potent arterial and venous dilator that decreases preload and afterload, thereby reducing myocardial oxygen demand. Nitroprusside is metabolized to cyanide, which must be monitored closely during therapy to prevent toxicity.

Pharmacologic class: Peripheral vasodilators

Therapeutic class: Antihypertensives, Vasodilators

Medical Categories: Cardiovascular Drugs, Hypertension Agents

Cyclic AMP (cAMP)-dependent protein kinases, also known as protein kinase A (PKA), are a family of enzymes that play a crucial role in intracellular signaling pathways. These enzymes are responsible for the regulation of various cellular processes, including metabolism, gene expression, and cell growth and differentiation.

PKA is composed of two regulatory subunits and two catalytic subunits. When cAMP binds to the regulatory subunits, it causes a conformational change that leads to the dissociation of the catalytic subunits. The freed catalytic subunits then phosphorylate specific serine and threonine residues on target proteins, thereby modulating their activity.

The cAMP-dependent protein kinases are activated in response to a variety of extracellular signals, such as hormones and neurotransmitters, that bind to G protein-coupled receptors (GPCRs) or receptor tyrosine kinases (RTKs). These signals lead to the activation of adenylyl cyclase, which catalyzes the conversion of ATP to cAMP. The resulting increase in intracellular cAMP levels triggers the activation of PKA and the downstream phosphorylation of target proteins.

Overall, cAMP-dependent protein kinases are essential regulators of many fundamental cellular processes and play a critical role in maintaining normal physiology and homeostasis. Dysregulation of these enzymes has been implicated in various diseases, including cancer, diabetes, and neurological disorders.

Theophylline is a medication that belongs to a class of drugs called methylxanthines. It is used in the management of respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and other conditions that cause narrowing of the airways in the lungs.

Theophylline works by relaxing the smooth muscle around the airways, which helps to open them up and make breathing easier. It also acts as a bronchodilator, increasing the flow of air into and out of the lungs. Additionally, theophylline has anti-inflammatory effects that can help reduce swelling in the airways and relieve symptoms such as coughing, wheezing, and shortness of breath.

Theophylline is available in various forms, including tablets, capsules, and liquid solutions. It is important to take this medication exactly as prescribed by a healthcare provider, as the dosage may vary depending on individual factors such as age, weight, and liver function. Regular monitoring of blood levels of theophylline is also necessary to ensure safe and effective use of the medication.

Cyclic peroxides, often referred to as cyclic peroxide compounds, are organic substances that contain a ring structure formed by two oxygen atoms bonded together (a peroxide group) and one or more hydrocarbon chains. These compounds can be found in various chemical and biological systems, including some natural products and synthetic materials.

Cyclic peroxides have potential applications in several areas, such as pharmaceuticals, agrochemicals, and polymer chemistry. However, they are also known to be potentially unstable and may decompose under certain conditions, releasing oxygen gas and generating free radicals that can cause oxidative damage to other molecules. Therefore, handling and storing cyclic peroxides require caution and appropriate safety measures.

It is worth noting that the term "P-Oxides" in the question may be a typo or a shorthand for "peroxides," as "P" does not have any specific meaning in this context.

Vinca alkaloids are a group of naturally occurring chemicals derived from the Madagascar periwinkle plant, Catharanthus roseus. They are known for their antineoplastic (cancer-fighting) properties and are used in chemotherapy to treat various types of cancer. Some examples of vinca alkaloids include vinblastine, vincristine, and vinorelbine. These agents work by disrupting the normal function of microtubules, which are important components of the cell's structure and play a critical role in cell division. By binding to tubulin, a protein that makes up microtubules, vinca alkaloids prevent the formation of mitotic spindles, which are necessary for cell division. This leads to cell cycle arrest and apoptosis (programmed cell death) in cancer cells. However, vinca alkaloids can also affect normal cells, leading to side effects such as neurotoxicity, myelosuppression, and gastrointestinal disturbances.

Atrial natriuretic factor (ANF), also known as atrial natriuretic peptide (ANP), is a hormone that is primarily produced and secreted by the atria of the heart in response to stretching of the cardiac muscle cells due to increased blood volume. ANF plays a crucial role in regulating body fluid homeostasis, blood pressure, and cardiovascular function.

The main physiological action of ANF is to promote sodium and water excretion by the kidneys, which helps lower blood volume and reduce blood pressure. ANF also relaxes vascular smooth muscle, dilates blood vessels, and inhibits the renin-angiotensin-aldosterone system (RAAS), further contributing to its blood pressure-lowering effects.

Defects in ANF production or action have been implicated in several cardiovascular disorders, including heart failure, hypertension, and kidney disease. Therefore, ANF and its analogs are being investigated as potential therapeutic agents for the treatment of these conditions.

Adenylate cyclase is an enzyme that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP). It plays a crucial role in various cellular processes, including signal transduction and metabolism. Adenylate cyclase is activated by hormones and neurotransmitters that bind to G-protein-coupled receptors on the cell membrane, leading to the production of cAMP, which then acts as a second messenger to regulate various intracellular responses. There are several isoforms of adenylate cyclase, each with distinct regulatory properties and subcellular localization.

Guanosine monophosphate (GMP) is a nucleotide that is a fundamental unit of genetic material in DNA and RNA. It consists of a guanine base, a pentose sugar (ribose in the case of RNA, deoxyribose in DNA), and one phosphate group. GMP plays crucial roles in various biochemical reactions within cells, including energy transfer and signal transduction pathways. Additionally, it is involved in the synthesis of important molecules like nucleic acids, neurotransmitters, and hormones.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

Colforsin is a drug that belongs to a class of medications called phosphodiesterase inhibitors. It works by increasing the levels of a chemical called cyclic AMP (cyclic adenosine monophosphate) in the body, which helps to relax and widen blood vessels.

Colforsin is not approved for use in humans in many countries, including the United States. However, it has been used in research settings to study its potential effects on heart function and other physiological processes. In animals, colforsin has been shown to have positive inotropic (contractility-enhancing) and lusitropic (relaxation-enhancing) effects on the heart, making it a potential therapeutic option for heart failure and other cardiovascular conditions.

It is important to note that while colforsin has shown promise in preclinical studies, more research is needed to establish its safety and efficacy in humans. Therefore, it should only be used under the supervision of a qualified healthcare professional and in the context of a clinical trial or research study.

8-Bromo Cyclic Adenosine Monophosphate (8-Br-cAMP) is a synthetic, cell-permeable analog of cyclic adenosine monophosphate (cAMP). Cyclic AMP is an important second messenger in many signal transduction pathways, and 8-Br-cAMP is often used in research to mimic or study the effects of increased cAMP levels. The bromine atom at the 8-position makes 8-Br-cAMP more resistant to degradation by phosphodiesterases, allowing it to have a longer duration of action compared to cAMP. It is used in various biochemical and cellular studies as a tool compound to investigate the role of cAMP in different signaling pathways.

Glycerylphosphorylcholine (GPC) is not typically considered a medical term, but it is a choline-containing phospholipid that can be found in various tissues and fluids within the human body. It is also available as a dietary supplement. Here's a definition of Glycerylphosphorylcholine:

Glycerylphosphorylcholine (GPC) is a natural choline-containing compound that is present in various tissues and fluids within the human body, including neural tissue, muscle, and blood. It plays an essential role in the synthesis of the neurotransmitter acetylcholine, which is involved in memory, learning, and other cognitive functions. GPC can also be found in some foods, such as egg yolks and soybeans, and is available as a dietary supplement. In the body, GPC can be converted to phosphatidylcholine, another important phospholipid that is necessary for maintaining cell membrane structure and function.

Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.

The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.

Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Isoproterenol is a medication that belongs to a class of drugs called beta-adrenergic agonists. Medically, it is defined as a synthetic catecholamine with both alpha and beta adrenergic receptor stimulating properties. It is primarily used as a bronchodilator to treat conditions such as asthma and chronic obstructive pulmonary disease (COPD) by relaxing the smooth muscles in the airways, thereby improving breathing.

Isoproterenol can also be used in the treatment of bradycardia (abnormally slow heart rate), cardiac arrest, and heart blocks by increasing the heart rate and contractility. However, due to its non-selective beta-agonist activity, it may cause various side effects such as tremors, palpitations, and increased blood pressure. Its use is now limited due to the availability of more selective and safer medications.

Oxadiazoles are heterocyclic compounds containing a five-membered ring consisting of two carbon atoms, one nitrogen atom, and two oxygen atoms in an alternating sequence. There are three possible isomers of oxadiazole, depending on the position of the nitrogen atom: 1,2,3-oxadiazole, 1,2,4-oxadiazole, and 1,3,4-oxadiazole. These compounds have significant interest in medicinal chemistry due to their diverse biological activities, including anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer properties. Some oxadiazoles also exhibit potential as contrast agents for medical imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT).

A catalytic domain is a portion or region within a protein that contains the active site, where the chemical reactions necessary for the protein's function are carried out. This domain is responsible for the catalysis of biological reactions, hence the name "catalytic domain." The catalytic domain is often composed of specific amino acid residues that come together to form the active site, creating a unique three-dimensional structure that enables the protein to perform its specific function.

In enzymes, for example, the catalytic domain contains the residues that bind and convert substrates into products through chemical reactions. In receptors, the catalytic domain may be involved in signal transduction or other regulatory functions. Understanding the structure and function of catalytic domains is crucial to understanding the mechanisms of protein function and can provide valuable insights for drug design and therapeutic interventions.

A rod cell outer segment is a specialized structure in the retina of the eye that is responsible for photoreception, or the conversion of light into electrical signals. Rod cells are one of the two types of photoreceptor cells in the retina, with the other type being cone cells. Rod cells are more sensitive to light than cone cells and are responsible for low-light vision and peripheral vision.

The outer segment of a rod cell is a long, thin structure that contains stacks of discs filled with the visual pigment rhodopsin. When light hits the rhodopsin molecules in the discs, it causes a chemical reaction that leads to the activation of a signaling pathway within the rod cell. This ultimately results in the generation of an electrical signal that is transmitted to the brain via the optic nerve.

The outer segment of a rod cell is constantly being regenerated and broken down through a process called shedding and renewal. The tips of the outer segments are shed and phagocytosed by cells called retinal pigment epithelial (RPE) cells, which help to maintain the health and function of the rod cells.

Xanthines are a type of natural alkaloids that are found in various plants, including tea leaves, cocoa beans, and mate. The most common xanthines are caffeine, theophylline, and theobromine. These compounds have stimulant effects on the central nervous system and are often used in medication to treat conditions such as asthma, bronchitis, and other respiratory issues.

Caffeine is the most widely consumed xanthine and is found in a variety of beverages like coffee, tea, and energy drinks. It works by blocking adenosine receptors in the brain, which can lead to increased alertness and reduced feelings of fatigue.

Theophylline is another xanthine that is used as a bronchodilator to treat asthma and other respiratory conditions. It works by relaxing smooth muscles in the airways, making it easier to breathe.

Theobromine is found in cocoa beans and is responsible for the stimulant effects of chocolate. While it has similar properties to caffeine and theophylline, it is less potent and has a milder effect on the body.

It's worth noting that while xanthines can have beneficial effects when used in moderation, they can also cause negative side effects such as insomnia, nervousness, and rapid heart rate if consumed in large quantities or over an extended period of time.

Hydrolysis is a chemical process, not a medical one. However, it is relevant to medicine and biology.

Hydrolysis is the breakdown of a chemical compound due to its reaction with water, often resulting in the formation of two or more simpler compounds. In the context of physiology and medicine, hydrolysis is a crucial process in various biological reactions, such as the digestion of food molecules like proteins, carbohydrates, and fats. Enzymes called hydrolases catalyze these hydrolysis reactions to speed up the breakdown process in the body.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Pyrophosphatases are enzymes that catalyze the hydrolysis or cleavage of pyrophosphate (PPi) into two inorganic phosphate (Pi) molecules. This reaction is essential for many biochemical processes, such as energy metabolism and biosynthesis pathways, where pyrophosphate is generated as a byproduct. By removing the pyrophosphate, pyrophosphatases help drive these reactions forward and maintain the thermodynamic equilibrium.

There are several types of pyrophosphatases found in various organisms and cellular compartments, including:

1. Inorganic Pyrophosphatase (PPiase): This enzyme is widely distributed across all kingdoms of life and is responsible for hydrolyzing inorganic pyrophosphate into two phosphates. It plays a crucial role in maintaining the cellular energy balance by ensuring that the reverse reaction, the formation of pyrophosphate from two phosphates, does not occur spontaneously.
2. Nucleotide Pyrophosphatases: These enzymes hydrolyze the pyrophosphate bond in nucleoside triphosphates (NTPs) and deoxynucleoside triphosphates (dNTPs), converting them into nucleoside monophosphates (NMPs) or deoxynucleoside monophosphates (dNMPs). This reaction is important for regulating the levels of NTPs and dNTPs in cells, which are necessary for DNA and RNA synthesis.
3. ATPases and GTPases: These enzymes belong to a larger family of P-loop NTPases that use the energy released from pyrophosphate bond hydrolysis to perform mechanical work or transport ions across membranes. Examples include the F1F0-ATP synthase, which synthesizes ATP using a proton gradient, and various molecular motors like myosin, kinesin, and dynein, which move along cytoskeletal filaments.

Overall, pyrophosphatases are essential for maintaining cellular homeostasis by regulating the levels of nucleotides and providing energy for various cellular processes.

Enzyme inhibitors are substances that bind to an enzyme and decrease its activity, preventing it from catalyzing a chemical reaction in the body. They can work by several mechanisms, including blocking the active site where the substrate binds, or binding to another site on the enzyme to change its shape and prevent substrate binding. Enzyme inhibitors are often used as drugs to treat various medical conditions, such as high blood pressure, abnormal heart rhythms, and bacterial infections. They can also be found naturally in some foods and plants, and can be used in research to understand enzyme function and regulation.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Muscle relaxation, in a medical context, refers to the process of reducing tension and promoting relaxation in the skeletal muscles. This can be achieved through various techniques, including progressive muscle relaxation (PMR), where individuals consciously tense and then release specific muscle groups in a systematic manner.

PMR has been shown to help reduce anxiety, stress, and muscle tightness, and improve overall well-being. It is often used as a complementary therapy in conjunction with other treatments for conditions such as chronic pain, headaches, and insomnia.

Additionally, muscle relaxation can also be facilitated through pharmacological interventions, such as the use of muscle relaxant medications. These drugs work by inhibiting the transmission of signals between nerves and muscles, leading to a reduction in muscle tone and spasticity. They are commonly used to treat conditions such as multiple sclerosis, cerebral palsy, and spinal cord injuries.

Photoreceptor cells are specialized neurons in the retina of the eye that convert light into electrical signals. These cells consist of two types: rods and cones. Rods are responsible for vision at low light levels and provide black-and-white, peripheral, and motion sensitivity. Cones are active at higher light levels and are capable of color discrimination and fine detail vision. Both types of photoreceptor cells contain light-sensitive pigments that undergo chemical changes when exposed to light, triggering a series of electrical signals that ultimately reach the brain and contribute to visual perception.

Enzyme activation refers to the process by which an enzyme becomes biologically active and capable of carrying out its specific chemical or biological reaction. This is often achieved through various post-translational modifications, such as proteolytic cleavage, phosphorylation, or addition of cofactors or prosthetic groups to the enzyme molecule. These modifications can change the conformation or structure of the enzyme, exposing or creating a binding site for the substrate and allowing the enzymatic reaction to occur.

For example, in the case of proteolytic cleavage, an inactive precursor enzyme, known as a zymogen, is cleaved into its active form by a specific protease. This is seen in enzymes such as trypsin and chymotrypsin, which are initially produced in the pancreas as inactive precursors called trypsinogen and chymotrypsinogen, respectively. Once they reach the small intestine, they are activated by enteropeptidase, a protease that cleaves a specific peptide bond, releasing the active enzyme.

Phosphorylation is another common mechanism of enzyme activation, where a phosphate group is added to a specific serine, threonine, or tyrosine residue on the enzyme by a protein kinase. This modification can alter the conformation of the enzyme and create a binding site for the substrate, allowing the enzymatic reaction to occur.

Enzyme activation is a crucial process in many biological pathways, as it allows for precise control over when and where specific reactions take place. It also provides a mechanism for regulating enzyme activity in response to various signals and stimuli, such as hormones, neurotransmitters, or changes in the intracellular environment.

I apologize for the confusion, but "Bucladesine" is not a recognized medical term or a medication in current use in medicine. It's possible that there may be some mistake or typo in the spelling. If you have any more context about where you encountered this term, I might be able to provide a more accurate and helpful response.

Sulfones are a group of medications that contain a sulfur atom bonded to two oxygen atoms and one other group, typically a hydrogen or carbon atom. They have various medical uses, including as antibacterial, antifungal, and anti-inflammatory agents. One example of a sulfone is dapsone, which is used to treat bacterial infections such as leprosy and Pneumocystis jirovecii pneumonia (PJP), as well as some inflammatory skin conditions. It's important to note that sulfones can have significant side effects and should only be used under the supervision of a healthcare professional.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

A smooth muscle within the vascular system refers to the involuntary, innervated muscle that is found in the walls of blood vessels. These muscles are responsible for controlling the diameter of the blood vessels, which in turn regulates blood flow and blood pressure. They are called "smooth" muscles because their individual muscle cells do not have the striations, or cross-striped patterns, that are observed in skeletal and cardiac muscle cells. Smooth muscle in the vascular system is controlled by the autonomic nervous system and by hormones, and can contract or relax slowly over a period of time.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Penicillamine is a medication that belongs to a class of drugs called chelating agents. It works by binding to heavy metals in the body, such as lead, mercury, or copper, and forming a compound that can be excreted in the urine. This helps to remove these harmful substances from the body.

Penicillamine is also used to treat certain medical conditions, such as rheumatoid arthritis, Wilson's disease (a genetic disorder that causes copper accumulation in the body), and cystinuria (a genetic disorder that causes an amino acid called cystine to accumulate in the kidneys and form stones).

It is important to note that penicillamine can have serious side effects, including kidney damage, so it should be used under the close supervision of a healthcare provider.

Purines are heterocyclic aromatic organic compounds that consist of a pyrimidine ring fused to an imidazole ring. They are fundamental components of nucleotides, which are the building blocks of DNA and RNA. In the body, purines can be synthesized endogenously or obtained through dietary sources such as meat, seafood, and certain vegetables.

Once purines are metabolized, they are broken down into uric acid, which is excreted by the kidneys. Elevated levels of uric acid in the body can lead to the formation of uric acid crystals, resulting in conditions such as gout or kidney stones. Therefore, maintaining a balanced intake of purine-rich foods and ensuring proper kidney function are essential for overall health.

A kinase anchor protein (AKAP) is a type of scaffolding protein that plays a role in organizing and targeting various signaling molecules within cells. AKAPs are so named because they can bind to and anchor protein kinases, enzymes that add phosphate groups to other proteins, thereby modulating their activity. This allows for the localized regulation of signaling pathways and helps ensure that specific cellular responses occur in the correct location and at the right time. AKAPs can also bind to other signaling molecules, such as phosphatases, ion channels, and second messenger systems, forming large complexes that facilitate efficient communication between different parts of the cell.

There are many different AKAPs identified in various organisms, and they play crucial roles in a wide range of cellular processes, including cell division, signal transduction, and gene expression. Mutations or dysregulation of AKAPs have been implicated in several diseases, including cancer, cardiovascular disease, and neurological disorders. Therefore, understanding the structure, function, and regulation of AKAPs is an important area of research with potential therapeutic implications.

Calmodulin is a small, ubiquitous calcium-binding protein that plays a critical role in various intracellular signaling pathways. It functions as a calcium sensor, binding to and regulating the activity of numerous target proteins upon calcium ion (Ca^2+^) binding. Calmodulin is expressed in all eukaryotic cells and participates in many cellular processes, including muscle contraction, neurotransmitter release, gene expression, metabolism, and cell cycle progression.

The protein contains four EF-hand motifs that can bind Ca^2+^ ions. Upon calcium binding, conformational changes occur in the calmodulin structure, exposing hydrophobic surfaces that facilitate its interaction with target proteins. Calmodulin's targets include enzymes (such as protein kinases and phosphatases), ion channels, transporters, and cytoskeletal components. By modulating the activity of these proteins, calmodulin helps regulate essential cellular functions in response to changes in intracellular Ca^2+^ concentrations.

Calmodulin's molecular weight is approximately 17 kDa, and it consists of a single polypeptide chain with 148-150 amino acid residues. The protein can be found in both the cytoplasm and the nucleus of cells. In addition to its role as a calcium sensor, calmodulin has been implicated in various pathological conditions, including cancer, neurodegenerative diseases, and cardiovascular disorders.

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

Vasodilator agents are pharmacological substances that cause the relaxation or widening of blood vessels by relaxing the smooth muscle in the vessel walls. This results in an increase in the diameter of the blood vessels, which decreases vascular resistance and ultimately reduces blood pressure. Vasodilators can be further classified based on their site of action:

1. Systemic vasodilators: These agents cause a generalized relaxation of the smooth muscle in the walls of both arteries and veins, resulting in a decrease in peripheral vascular resistance and preload (the volume of blood returning to the heart). Examples include nitroglycerin, hydralazine, and calcium channel blockers.
2. Arterial vasodilators: These agents primarily affect the smooth muscle in arterial vessel walls, leading to a reduction in afterload (the pressure against which the heart pumps blood). Examples include angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and direct vasodilators like sodium nitroprusside.
3. Venous vasodilators: These agents primarily affect the smooth muscle in venous vessel walls, increasing venous capacitance and reducing preload. Examples include nitroglycerin and other organic nitrates.

Vasodilator agents are used to treat various cardiovascular conditions such as hypertension, heart failure, angina, and pulmonary arterial hypertension. It is essential to monitor their use carefully, as excessive vasodilation can lead to orthostatic hypotension, reflex tachycardia, or fluid retention.

Atrial natriuretic factor (ANF) receptors are specialized proteins found on the surface of certain cells in the body, primarily in the kidneys, heart, and blood vessels. They play a crucial role in regulating blood pressure, volume, and electrolyte balance.

There are two main types of ANF receptors: type A and type B. Type A receptors, also known as guanylyl cyclase-A (GC-A) receptors, are found in the kidneys, heart, and blood vessels. When ANF binds to these receptors, it triggers a series of reactions that lead to an increase in the production of a molecule called cyclic GMP (cGMP). This, in turn, causes vasodilation (relaxation of blood vessels), increased urine production, and reduced sodium reabsorption in the kidneys, all of which help lower blood pressure.

Type B receptors, on the other hand, are found mainly in the brain and have been shown to modulate the release of ANF from the heart. When ANF binds to type B receptors, it inhibits the release of vasopressin, a hormone that helps regulate water balance in the body. This further contributes to the overall effects of ANF on blood pressure and fluid balance.

Overall, ANF receptors are essential components of the complex system that helps maintain homeostasis in the cardiovascular and renal systems.

'Dictyostelium' is a genus of social amoebae that are commonly found in soil and decaying organic matter. These microscopic organisms have a unique life cycle, starting as individual cells that feed on bacteria. When food becomes scarce, the cells undergo a developmental process where they aggregate together to form a multicellular slug-like structure called a pseudoplasmodium or grex. This grex then moves and differentiates into a fruiting body that can release spores for further reproduction.

Dictyostelium discoideum is the most well-studied species in this genus, serving as a valuable model organism for research in various fields such as cell biology, developmental biology, and evolutionary biology. The study of Dictyostelium has contributed significantly to our understanding of fundamental biological processes like chemotaxis, signal transduction, and cell differentiation.

The thoracic aorta is the segment of the largest artery in the human body (the aorta) that runs through the chest region (thorax). The thoracic aorta begins at the aortic arch, where it branches off from the ascending aorta, and extends down to the diaphragm, where it becomes the abdominal aorta.

The thoracic aorta is divided into three parts: the ascending aorta, the aortic arch, and the descending aorta. The ascending aorta rises from the left ventricle of the heart and is about 2 inches (5 centimeters) long. The aortic arch curves backward and to the left, giving rise to the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. The descending thoracic aorta runs downward through the chest, passing through the diaphragm to become the abdominal aorta.

The thoracic aorta supplies oxygenated blood to the upper body, including the head, neck, arms, and chest. It plays a critical role in maintaining blood flow and pressure throughout the body.

S-Nitroso-N-Acetylpenicillamine (SNAP) is not a medication itself, but rather a chemical compound that is used in laboratory research. It is a nitrosothiol, which means it contains a nitric oxide group (NO) attached to a sulfur atom in a thiol group (a type of organic compound containing a sulfhydryl group, -SH).

Nitric oxide is a small signaling molecule that plays an important role in various biological processes, including the regulation of blood flow, immune response, and neurotransmission. SNAP is often used as a nitric oxide donor in scientific studies to investigate the effects of nitric oxide on different cells and tissues.

SNAP can release nitric oxide under certain conditions, such as in the presence of reducing agents or at acidic pH levels. This makes it useful for studying the mechanisms of nitric oxide-mediated signaling pathways and its potential therapeutic applications. However, SNAP is not used as a medication in clinical practice due to its instability and potential toxicity.

Gene expression regulation, enzymologic refers to the biochemical processes and mechanisms that control the transcription and translation of specific genes into functional proteins or enzymes. This regulation is achieved through various enzymatic activities that can either activate or repress gene expression at different levels, such as chromatin remodeling, transcription factor activation, mRNA processing, and protein degradation.

Enzymologic regulation of gene expression involves the action of specific enzymes that catalyze chemical reactions involved in these processes. For example, histone-modifying enzymes can alter the structure of chromatin to make genes more or less accessible for transcription, while RNA polymerase and its associated factors are responsible for transcribing DNA into mRNA. Additionally, various enzymes are involved in post-transcriptional modifications of mRNA, such as splicing, capping, and tailing, which can affect the stability and translation of the transcript.

Overall, the enzymologic regulation of gene expression is a complex and dynamic process that allows cells to respond to changes in their environment and maintain proper physiological function.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

Isoquinolines are not a medical term per se, but a chemical classification. They refer to a class of organic compounds that consist of a benzene ring fused to a piperidine ring. This structure is similar to that of quinoline, but with the nitrogen atom located at a different position in the ring.

Isoquinolines have various biological activities and can be found in some natural products, including certain alkaloids. Some isoquinoline derivatives have been developed as drugs for the treatment of various conditions, such as cardiovascular diseases, neurological disorders, and cancer. However, specific medical definitions related to isoquinolines typically refer to the use or effects of these specific drugs rather than the broader class of compounds.

Arginine is an α-amino acid that is classified as a semi-essential or conditionally essential amino acid, depending on the developmental stage and health status of the individual. The adult human body can normally synthesize sufficient amounts of arginine to meet its needs, but there are certain circumstances, such as periods of rapid growth or injury, where the dietary intake of arginine may become necessary.

The chemical formula for arginine is C6H14N4O2. It has a molecular weight of 174.20 g/mol and a pKa value of 12.48. Arginine is a basic amino acid, which means that it contains a side chain with a positive charge at physiological pH levels. The side chain of arginine is composed of a guanidino group, which is a functional group consisting of a nitrogen atom bonded to three methyl groups.

In the body, arginine plays several important roles. It is a precursor for the synthesis of nitric oxide, a molecule that helps regulate blood flow and immune function. Arginine is also involved in the detoxification of ammonia, a waste product produced by the breakdown of proteins. Additionally, arginine can be converted into other amino acids, such as ornithine and citrulline, which are involved in various metabolic processes.

Foods that are good sources of arginine include meat, poultry, fish, dairy products, nuts, seeds, and legumes. Arginine supplements are available and may be used for a variety of purposes, such as improving exercise performance, enhancing wound healing, and boosting immune function. However, it is important to consult with a healthcare provider before taking arginine supplements, as they can interact with certain medications and have potential side effects.

Subcellular fractions refer to the separation and collection of specific parts or components of a cell, including organelles, membranes, and other structures, through various laboratory techniques such as centrifugation and ultracentrifugation. These fractions can be used in further biochemical and molecular analyses to study the structure, function, and interactions of individual cellular components. Examples of subcellular fractions include nuclear extracts, mitochondrial fractions, microsomal fractions (membrane vesicles), and cytosolic fractions (cytoplasmic extracts).

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

I must clarify that the term "Guinea Pigs" is not typically used in medical definitions. However, in colloquial or informal language, it may refer to people who are used as the first to try out a new medical treatment or drug. This is known as being a "test subject" or "in a clinical trial."

In the field of scientific research, particularly in studies involving animals, guinea pigs are small rodents that are often used as experimental subjects due to their size, cost-effectiveness, and ease of handling. They are not actually pigs from Guinea, despite their name's origins being unclear. However, they do not exactly fit the description of being used in human medical experiments.

Carbolines are a type of chemical compound that contain a carbazole or dibenzopyrrole structure. These compounds have a variety of uses, including as pharmaceuticals and dyes. Some carbolines have been studied for their potential medicinal properties, such as their ability to act as antioxidants or to inhibit the growth of certain types of cells. However, it is important to note that many carbolines are also known to be toxic and can cause harm if ingested or otherwise introduced into the body. As with any chemical compound, it is essential to use caution when handling carbolines and to follow all safety guidelines to minimize the risk of exposure.

Quinoxalines are not a medical term, but rather an organic chemical compound. They are a class of heterocyclic aromatic compounds made up of a benzene ring fused to a pyrazine ring. Quinoxalines have no specific medical relevance, but some of their derivatives have been synthesized and used in medicinal chemistry as antibacterial, antifungal, and antiviral agents. They are also used in the production of dyes and pigments.

Quinolones are a class of antibacterial agents that are widely used in medicine to treat various types of infections caused by susceptible bacteria. These synthetic drugs contain a chemical structure related to quinoline and have broad-spectrum activity against both Gram-positive and Gram-negative bacteria. Quinolones work by inhibiting the bacterial DNA gyrase or topoisomerase IV enzymes, which are essential for bacterial DNA replication, transcription, and repair.

The first quinolone antibiotic was nalidixic acid, discovered in 1962. Since then, several generations of quinolones have been developed, with each generation having improved antibacterial activity and a broader spectrum of action compared to the previous one. The various generations of quinolones include:

1. First-generation quinolones (e.g., nalidixic acid): Primarily used for treating urinary tract infections caused by Gram-negative bacteria.
2. Second-generation quinolones (e.g., ciprofloxacin, ofloxacin, norfloxacin): These drugs have improved activity against both Gram-positive and Gram-negative bacteria and are used to treat a wider range of infections, including respiratory, gastrointestinal, and skin infections.
3. Third-generation quinolones (e.g., levofloxacin, sparfloxacin, grepafloxacin): These drugs have enhanced activity against Gram-positive bacteria, including some anaerobes and atypical organisms like Legionella and Mycoplasma species.
4. Fourth-generation quinolones (e.g., moxifloxacin, gatifloxacin): These drugs have the broadest spectrum of activity, including enhanced activity against Gram-positive bacteria, anaerobes, and some methicillin-resistant Staphylococcus aureus (MRSA) strains.

Quinolones are generally well-tolerated, but like all medications, they can have side effects. Common adverse reactions include gastrointestinal symptoms (nausea, vomiting, diarrhea), headache, and dizziness. Serious side effects, such as tendinitis, tendon rupture, peripheral neuropathy, and QT interval prolongation, are less common but can occur, particularly in older patients or those with underlying medical conditions. The use of quinolones should be avoided or used cautiously in these populations.

Quinolone resistance has become an increasing concern due to the widespread use of these antibiotics. Bacteria can develop resistance through various mechanisms, including chromosomal mutations and the acquisition of plasmid-mediated quinolone resistance genes. The overuse and misuse of quinolones contribute to the emergence and spread of resistant strains, which can limit treatment options for severe infections caused by these bacteria. Therefore, it is essential to use quinolones judiciously and only when clinically indicated, to help preserve their effectiveness and prevent further resistance development.

The endothelium is a thin layer of simple squamous epithelial cells that lines the interior surface of blood vessels, lymphatic vessels, and heart chambers. The vascular endothelium, specifically, refers to the endothelial cells that line the blood vessels. These cells play a crucial role in maintaining vascular homeostasis by regulating vasomotor tone, coagulation, platelet activation, inflammation, and permeability of the vessel wall. They also contribute to the growth and repair of the vascular system and are involved in various pathological processes such as atherosclerosis, hypertension, and diabetes.

Molsidomine is a medication that belongs to a class of drugs called vasodilators. It works by relaxing and widening blood vessels, which helps to improve blood flow and reduce the workload on the heart. Molsidomine is used to treat chronic stable angina (chest pain caused by reduced blood flow to the heart) and has been found to be effective in reducing the frequency and severity of anginal attacks.

When molsidomine is absorbed into the body, it is converted into its active metabolite, SIN-1, which is responsible for its vasodilatory effects. SIN-1 causes smooth muscle relaxation by increasing the levels of nitric oxide in the blood vessels, leading to their dilation and improved blood flow.

Molsidomine is available in tablet form and is typically taken two to three times a day, with or without food. Common side effects of molsidomine include headache, dizziness, flushing, and palpitations. It should be used with caution in patients with low blood pressure, heart failure, or impaired kidney function.

GMP (guanosine monophosphate) reductase is an enzyme that plays a crucial role in the metabolism of nucleotides, specifically within the purine nucleotide pathway. This enzyme catalyzes the NADH-dependent reduction of GMP to IMP (inosine monophosphate), which is a key step in the de novo biosynthesis of purines and the salvage pathways for purine nucleotides.

GMP reductase is found in various organisms, including bacteria, fungi, and plants. In humans, two isoforms of GMP reductase exist: a cytosolic form (IRI1) and a mitochondrial form (IRI2). The enzyme's activity is tightly regulated, as it is involved in balancing the intracellular pools of purine nucleotides. Dysregulation of GMP reductase has been implicated in several diseases, such as cancer and neurological disorders.

Medical Definition:
GMP reductase (guanosine monophosphate reductase): An enzyme (EC 1.17.1.4) that catalyzes the NADH-dependent reduction of GMP to IMP, with the concomitant formation of hydrogen peroxide (H2O2). This enzyme is involved in the de novo biosynthesis and salvage pathways of purine nucleotides. In humans, two isoforms of GMP reductase exist: a cytosolic form (IRI1) and a mitochondrial form (IRI2).

Nitric oxide (NO) donors are pharmacological agents that release nitric oxide in the body when they are metabolized. Nitric oxide is a molecule that plays an important role as a signaling messenger in the cardiovascular, nervous, and immune systems. It helps regulate blood flow, relax smooth muscle, inhibit platelet aggregation, and modulate inflammatory responses.

NO donors can be used medically to treat various conditions, such as hypertension, angina, heart failure, and pulmonary hypertension, by promoting vasodilation and improving blood flow. Some examples of NO donors include nitroglycerin, isosorbide dinitrate, sodium nitroprusside, and molsidomine. These drugs work by releasing nitric oxide slowly over time, which then interacts with the enzyme soluble guanylate cyclase to produce cyclic guanosine monophosphate (cGMP), leading to relaxation of smooth muscle and vasodilation.

It is important to note that NO donors can have side effects, such as headache, dizziness, and hypotension, due to their vasodilatory effects. Therefore, they should be used under the guidance of a healthcare professional.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Nitric Oxide Synthase (NOS) is a group of enzymes that catalyze the production of nitric oxide (NO) from L-arginine. There are three distinct isoforms of NOS, each with different expression patterns and functions:

1. Neuronal Nitric Oxide Synthase (nNOS or NOS1): This isoform is primarily expressed in the nervous system and plays a role in neurotransmission, synaptic plasticity, and learning and memory processes.
2. Inducible Nitric Oxide Synthase (iNOS or NOS2): This isoform is induced by various stimuli such as cytokines, lipopolysaccharides, and hypoxia in a variety of cells including immune cells, endothelial cells, and smooth muscle cells. iNOS produces large amounts of NO, which functions as a potent effector molecule in the immune response, particularly in the defense against microbial pathogens.
3. Endothelial Nitric Oxide Synthase (eNOS or NOS3): This isoform is constitutively expressed in endothelial cells and produces low levels of NO that play a crucial role in maintaining vascular homeostasis by regulating vasodilation, inhibiting platelet aggregation, and preventing smooth muscle cell proliferation.

Overall, NOS plays an essential role in various physiological processes, including neurotransmission, immune response, cardiovascular function, and respiratory regulation. Dysregulation of NOS activity has been implicated in several pathological conditions such as hypertension, atherosclerosis, neurodegenerative diseases, and inflammatory disorders.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

"Rana catesbeiana" is the scientific name for the American bullfrog, which is not a medical term or concept. It belongs to the animal kingdom, specifically in the order Anura and family Ranidae. The American bullfrog is native to North America and is known for its large size and distinctive loud call.

However, if you are looking for a medical definition, I apologize for any confusion. Please provide more context or specify the term you would like me to define.

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst, which remains unchanged at the end of the reaction. A catalyst lowers the activation energy required for the reaction to occur, thereby allowing the reaction to proceed more quickly and efficiently. This can be particularly important in biological systems, where enzymes act as catalysts to speed up metabolic reactions that are essential for life.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Dipyridamole is a medication that belongs to a class of drugs called antiplatelet agents. It works by preventing platelets in your blood from sticking together to form clots. Dipyridamole is often used in combination with aspirin to prevent stroke and other complications in people who have had a heart valve replacement or a type of irregular heartbeat called atrial fibrillation.

Dipyridamole can also be used as a stress agent in myocardial perfusion imaging studies, which are tests used to evaluate blood flow to the heart. When used for this purpose, dipyridamole is given intravenously and works by dilating the blood vessels in the heart, allowing more blood to flow through them and making it easier to detect areas of reduced blood flow.

The most common side effects of dipyridamole include headache, dizziness, and gastrointestinal symptoms such as diarrhea, nausea, and vomiting. In rare cases, dipyridamole can cause more serious side effects, such as allergic reactions, abnormal heart rhythms, or low blood pressure. It is important to take dipyridamole exactly as directed by your healthcare provider and to report any unusual symptoms or side effects promptly.

Adenine nucleotides are molecules that consist of a nitrogenous base called adenine, which is linked to a sugar molecule (ribose in the case of adenosine monophosphate or AMP, and deoxyribose in the case of adenosine diphosphate or ADP and adenosine triphosphate or ATP) and one, two, or three phosphate groups. These molecules play a crucial role in energy transfer and metabolism within cells.

AMP contains one phosphate group, while ADP contains two phosphate groups, and ATP contains three phosphate groups. When a phosphate group is removed from ATP, energy is released, which can be used to power various cellular processes such as muscle contraction, nerve impulse transmission, and protein synthesis. The reverse reaction, in which a phosphate group is added back to ADP or AMP to form ATP, requires energy input and often involves the breakdown of nutrients such as glucose or fatty acids.

In addition to their role in energy metabolism, adenine nucleotides also serve as precursors for other important molecules, including DNA and RNA, coenzymes, and signaling molecules.

Cytosol refers to the liquid portion of the cytoplasm found within a eukaryotic cell, excluding the organelles and structures suspended in it. It is the site of various metabolic activities and contains a variety of ions, small molecules, and enzymes. The cytosol is where many biochemical reactions take place, including glycolysis, protein synthesis, and the regulation of cellular pH. It is also where some organelles, such as ribosomes and vesicles, are located. In contrast to the cytosol, the term "cytoplasm" refers to the entire contents of a cell, including both the cytosol and the organelles suspended within it.

Cyclic guanosine monophosphate (cGMP)-dependent protein kinase type I (PKG I) is a major enzyme responsible for mediating the effects of cGMP, which is a second messenger molecule involved in various cellular signaling pathways. PKG I is a serine/threonine protein kinase that is activated by binding to cGMP.

PKG I exists in two isoforms, alpha and beta, which are encoded by separate genes but share a similar structure and function. The enzyme consists of a regulatory domain, which contains the cGMP-binding sites, and a catalytic domain, which carries out the phosphorylation of target proteins.

PKG I plays a critical role in regulating various physiological processes, including smooth muscle relaxation, cardiac contractility, platelet aggregation, and neuronal signaling. It does so by phosphorylating specific protein targets that control these processes, such as ion channels, enzymes, and cytoskeletal proteins.

Defects in PKG I function have been implicated in several human diseases, including pulmonary hypertension, heart failure, and erectile dysfunction. Therefore, PKG I is an important therapeutic target for the development of drugs to treat these conditions.

Piperazines are a class of heterocyclic organic compounds that contain a seven-membered ring with two nitrogen atoms at positions 1 and 4. They have the molecular formula N-NRR' where R and R' can be alkyl or aryl groups. Piperazines have a wide range of uses in pharmaceuticals, agrochemicals, and as building blocks in organic synthesis.

In a medical context, piperazines are used in the manufacture of various drugs, including some antipsychotics, antidepressants, antihistamines, and anti-worm medications. For example, the antipsychotic drug trifluoperazine and the antidepressant drug nefazodone both contain a piperazine ring in their chemical structure.

However, it's important to note that some piperazines are also used as recreational drugs due to their stimulant and euphoric effects. These include compounds such as BZP (benzylpiperazine) and TFMPP (trifluoromethylphenylpiperazine), which have been linked to serious health risks, including addiction, seizures, and death. Therefore, the use of these substances should be avoided.

Aminoquinolines are a class of drugs that contain a quinoline chemical structure and an amino group. They are primarily used as antimalarial agents, with the most well-known members of this class being chloroquine and hydroxychloroquine. These drugs work by inhibiting the parasite's ability to digest hemoglobin in the red blood cells, which is necessary for its survival and reproduction.

In addition to their antimalarial properties, aminoquinolines have also been studied for their potential anti-inflammatory and immunomodulatory effects. They have been investigated as a treatment for various autoimmune diseases, such as rheumatoid arthritis and lupus, although their use in these conditions is not yet widely accepted.

It's important to note that aminoquinolines can have significant side effects, including gastrointestinal symptoms, retinopathy, and cardiac toxicity. They should only be used under the close supervision of a healthcare provider, and their use may be contraindicated in certain populations, such as pregnant women or individuals with preexisting heart conditions.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

Dinucleoside phosphates are the chemical compounds that result from the linkage of two nucleosides through a phosphate group. Nucleosides themselves consist of a sugar molecule (ribose or deoxyribose) and a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil). When two nucleosides are joined together by an ester bond between the phosphate group and the 5'-hydroxyl group of the sugar moiety, they form a dinucleoside phosphate.

These compounds play crucial roles in various biological processes, particularly in the context of DNA and RNA synthesis and repair. For instance, dinucleoside phosphates serve as building blocks for the formation of longer nucleic acid chains during replication and transcription. They are also involved in signaling pathways and energy transfer within cells.

It is worth noting that the term "dinucleotides" is sometimes used interchangeably with dinucleoside phosphates, although technically, dinucleotides refer to compounds formed by joining two nucleotides (nucleosides plus one or more phosphate groups) rather than just two nucleosides.

Nitro-L-arginine or Nitroarginine is not a medical term per se, but it is a chemical compound that is sometimes used in medical research and experiments. It is a salt of nitric acid and L-arginine, an amino acid that is important for the functioning of the body.

Nitroarginine is known to inhibit the production of nitric oxide, a molecule that plays a role in various physiological processes such as blood flow regulation, immune response, and neurotransmission. As a result, nitroarginine has been used in research to study the effects of reduced nitric oxide levels on different systems in the body.

It's worth noting that nitroarginine is not approved for use as a medication in humans, and its use is generally limited to laboratory settings.

Nitroso compounds are a class of chemical compounds that contain a nitroso functional group, which is composed of a nitrogen atom bonded to an oxygen atom with a single covalent bond. The general formula for nitroso compounds is R-N=O, where R represents an organic group such as an alkyl or aryl group.

Nitroso compounds are known to be reactive and can form under various physiological conditions. They have been implicated in the formation of carcinogenic substances and have been linked to DNA damage and mutations. In the medical field, nitroso compounds have been studied for their potential use as therapeutic agents, particularly in the treatment of cancer and cardiovascular diseases. However, their use is limited due to their potential toxicity and carcinogenicity.

It's worth noting that exposure to high levels of nitroso compounds can be harmful to human health, and may cause respiratory, dermal, and ocular irritation, as well as potential genotoxic effects. Therefore, handling and storage of nitroso compounds should be done with caution, following appropriate safety guidelines.

Natriuretic peptides are a group of hormones that help regulate the balance of sodium and water in the body, as well as blood volume and blood pressure. They are produced by the heart and other tissues in response to stretching or distension of the cells due to increased fluid volume.

There are several types of natriuretic peptides, including:

1. Atrial natriuretic peptide (ANP): This hormone is produced by the atria of the heart in response to stretching of the atrial walls caused by increased blood volume. ANP promotes sodium and water excretion by the kidneys, which helps lower blood pressure and reduce fluid volume.
2. Brain natriuretic peptide (BNP): This hormone is produced by the ventricles of the heart in response to stretching of the ventricular walls caused by increased blood volume or pressure. BNP also promotes sodium and water excretion by the kidneys, as well as dilating blood vessels and reducing the force of heart contractions.
3. C-type natriuretic peptide (CNP): This hormone is produced by endothelial cells lining the blood vessels and has similar effects to ANP and BNP, but its main role is to regulate bone growth and development.

Natriuretic peptides have important diagnostic and therapeutic implications in various medical conditions, such as heart failure, hypertension, and kidney disease. Elevated levels of natriuretic peptides may indicate the presence of cardiac dysfunction or damage, while administering synthetic forms of these hormones has been shown to have beneficial effects on blood pressure, fluid balance, and cardiovascular function.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

Phosphorylation is the process of adding a phosphate group (a molecule consisting of one phosphorus atom and four oxygen atoms) to a protein or other organic molecule, which is usually done by enzymes called kinases. This post-translational modification can change the function, localization, or activity of the target molecule, playing a crucial role in various cellular processes such as signal transduction, metabolism, and regulation of gene expression. Phosphorylation is reversible, and the removal of the phosphate group is facilitated by enzymes called phosphatases.

Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that play a crucial role in regulating intracellular levels of cyclic nucleotides, which are important second messengers in various cellular signaling pathways. Among the different types of PDEs, type 6 (PDE6) is specifically expressed in the photoreceptor cells of the retina and is involved in the visual signal transduction cascade.

PDE6 is composed of two catalytic subunits, PDE6α and PDE6β, which are arranged in a heterodimeric complex. These subunits have distinct roles in the enzyme's activity: PDE6α contains the catalytic site that hydrolyzes cyclic guanosine monophosphate (cGMP) to GMP, while PDE6β regulates the activity of PDE6α through its inhibitory γ subunit.

In the visual signal transduction pathway, light stimulation leads to the activation of rhodopsin, which triggers a cascade of events that ultimately results in the hydrolysis of cGMP by PDE6. This reduction in cGMP levels causes the closure of cyclic nucleotide-gated channels in the plasma membrane, leading to hyperpolarization of the photoreceptor cells and the transmission of visual signals to the brain.

Defects in PDE6 have been implicated in various retinal disorders, including congenital stationary night blindness, retinitis pigmentosa, and age-related macular degeneration. Therefore, understanding the structure and function of PDE6 is essential for developing novel therapeutic strategies to treat these vision-threatening diseases.

Carbachol is a cholinergic agonist, which means it stimulates the parasympathetic nervous system by mimicking the action of acetylcholine, a neurotransmitter that is involved in transmitting signals between nerves and muscles. Carbachol binds to both muscarinic and nicotinic receptors, but its effects are more pronounced on muscarinic receptors.

Carbachol is used in medical treatments to produce miosis (pupil constriction), lower intraocular pressure, and stimulate gastrointestinal motility. It can also be used as a diagnostic tool to test for certain conditions such as Hirschsprung's disease.

Like any medication, carbachol can have side effects, including sweating, salivation, nausea, vomiting, diarrhea, bradycardia (slow heart rate), and bronchoconstriction (narrowing of the airways in the lungs). It should be used with caution and under the supervision of a healthcare professional.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Omega-N-Methylarginine (also known as NG, NG-dimethyl-L-arginine) is not a commonly used medical term and it's not a well-known compound in medicine. However, it is a form of methylated arginine that can be found in the body.

Methylated arginines are a group of compounds that are generated through the post-translational modification of proteins by enzymes called protein arginine methyltransferases (PRMTs). These modifications play important roles in various cellular processes, including gene expression and signal transduction.

Omega-N-Methylarginine is a specific type of methylated arginine that has two methyl groups attached to the nitrogen atom at the end of the side chain (omega position) of the amino acid arginine. It can be formed by the action of PRMTs on proteins, and it may have various biological functions in the body. However, its specific medical significance is not well-established, and more research is needed to fully understand its role in health and disease.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

C-type Natriuretic Peptide (CNP) is a member of the natriuretic peptide family, which are hormones that play crucial roles in cardiovascular homeostasis and renal function. The natriuretic peptides include atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP).

C-type Natriuretic Peptide is primarily produced and secreted by the endothelial cells, and to a lesser extent by the central nervous system, chondrocytes, and vascular smooth muscle cells. CNP has a relatively short half-life of approximately 2 minutes due to its rapid clearance by the natriuretic peptide receptor-C (NPR-C) and neutral endopeptidase (NEP).

The primary physiological function of C-type Natriuretic Peptide is to regulate vascular tone, endothelial cell growth, differentiation, and survival. It also plays a role in bone development and maintenance by promoting chondrocyte proliferation and differentiation. In the kidney, CNP influences renal function through its effects on natriuresis (sodium excretion), diuresis (water excretion), and vasodilation of the afferent arteriole.

CNP binds to the NPR-B receptor, which is widely expressed in various tissues, including vascular endothelial cells, cardiomyocytes, osteoblasts, chondrocytes, and neurons. The activation of NPR-B leads to increased intracellular cyclic guanosine monophosphate (cGMP) levels, which in turn activates protein kinase G (PKG), resulting in vasodilation, anti-proliferative, and natriuretic effects.

Dysregulation of C-type Natriuretic Peptide has been implicated in several pathological conditions, such as cardiovascular diseases, bone disorders, and cancer. Therefore, understanding the role of CNP in these processes may provide novel therapeutic targets for treating these diseases.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

S-Nitrosoglutathione (GSNO) is defined as a type of nitrosothiol, which is a class of compounds containing a nitroso (−NO) group attached to a sulfur atom. Specifically, GSNO is the result of the attachment of a nitric oxide (NO) molecule to the sulfur atom of the tripeptide glutathione (GSH). This compound has been the subject of extensive research due to its potential role in the regulation of various biological processes, including cell signaling, vasodilation, and neurotransmission, among others. It is also known to have antioxidant properties and to play a role in the immune response. However, it should be noted that abnormal levels of GSNO have been associated with various pathological conditions, such as cancer, neurodegenerative diseases, and cardiovascular disorders.

Ion exchange chromatography is a type of chromatography technique used to separate and analyze charged molecules (ions) based on their ability to exchange bound ions in a solid resin or gel with ions of similar charge in the mobile phase. The stationary phase, often called an ion exchanger, contains fixed ated functional groups that can attract counter-ions of opposite charge from the sample mixture.

In this technique, the sample is loaded onto an ion exchange column containing the charged resin or gel. As the sample moves through the column, ions in the sample compete for binding sites on the stationary phase with ions already present in the column. The ions that bind most strongly to the stationary phase will elute (come off) slower than those that bind more weakly.

Ion exchange chromatography can be performed using either cation exchangers, which exchange positive ions (cations), or anion exchangers, which exchange negative ions (anions). The pH and ionic strength of the mobile phase can be adjusted to control the binding and elution of specific ions.

Ion exchange chromatography is widely used in various applications such as water treatment, protein purification, and chemical analysis.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Myocardial contraction refers to the rhythmic and forceful shortening of heart muscle cells (myocytes) in the myocardium, which is the muscular wall of the heart. This process is initiated by electrical signals generated by the sinoatrial node, causing a wave of depolarization that spreads throughout the heart.

During myocardial contraction, calcium ions flow into the myocytes, triggering the interaction between actin and myosin filaments, which are the contractile proteins in the muscle cells. This interaction causes the myofilaments to slide past each other, resulting in the shortening of the sarcomeres (the functional units of muscle contraction) and ultimately leading to the contraction of the heart muscle.

Myocardial contraction is essential for pumping blood throughout the body and maintaining adequate circulation to vital organs. Any impairment in myocardial contractility can lead to various cardiac disorders, such as heart failure, cardiomyopathy, and arrhythmias.

Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.

Molecular weight, also known as molecular mass, is the mass of a molecule. It is expressed in units of atomic mass units (amu) or daltons (Da). Molecular weight is calculated by adding up the atomic weights of each atom in a molecule. It is a useful property in chemistry and biology, as it can be used to determine the concentration of a substance in a solution, or to calculate the amount of a substance that will react with another in a chemical reaction.

Acetylcholine is a neurotransmitter, a type of chemical messenger that transmits signals across a chemical synapse from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. It is involved in both peripheral and central nervous system functions.

In the peripheral nervous system, acetylcholine acts as a neurotransmitter at the neuromuscular junction, where it transmits signals from motor neurons to activate muscles. Acetylcholine also acts as a neurotransmitter in the autonomic nervous system, where it is involved in both the sympathetic and parasympathetic systems.

In the central nervous system, acetylcholine plays a role in learning, memory, attention, and arousal. Disruptions in cholinergic neurotransmission have been implicated in several neurological disorders, including Alzheimer's disease, Parkinson's disease, and myasthenia gravis.

Acetylcholine is synthesized from choline and acetyl-CoA by the enzyme choline acetyltransferase and is stored in vesicles at the presynaptic terminal of the neuron. When a nerve impulse arrives, the vesicles fuse with the presynaptic membrane, releasing acetylcholine into the synapse. The acetylcholine then binds to receptors on the postsynaptic membrane, triggering a response in the target cell. Acetylcholine is subsequently degraded by the enzyme acetylcholinesterase, which terminates its action and allows for signal transduction to be repeated.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

NG-Nitroarginine Methyl Ester (L-NAME) is not a medication, but rather a research chemical used in scientific studies. It is an inhibitor of nitric oxide synthase, an enzyme that synthesizes nitric oxide, a molecule involved in the relaxation of blood vessels.

Therefore, L-NAME is often used in experiments to investigate the role of nitric oxide in various physiological and pathophysiological processes. It is important to note that the use of L-NAME in humans is not approved for therapeutic purposes due to its potential side effects, which can include hypertension, decreased renal function, and decreased cerebral blood flow.

Trazodone is an antidepressant medication that belongs to the class of drugs called serotonin antagonist and reuptake inhibitors (SARIs). It works by increasing the levels of the neurotransmitter serotonin in the brain, which helps to improve mood and reduce symptoms of depression.

Trazodone is primarily used to treat major depressive disorder, but it may also be prescribed for anxiety, insomnia, and other conditions. The medication comes in various forms, including tablets and an extended-release formulation, and is typically taken orally one to three times a day. Common side effects of trazodone include dizziness, dry mouth, and sedation.

It's important to note that trazodone can interact with other medications and substances, so it's essential to inform your healthcare provider about all the drugs you are taking before starting treatment. Additionally, trazodone may increase the risk of suicidal thoughts or behavior in some people, particularly during the initial stages of treatment, so close monitoring is necessary.

A chemical stimulation in a medical context refers to the process of activating or enhancing physiological or psychological responses in the body using chemical substances. These chemicals can interact with receptors on cells to trigger specific reactions, such as neurotransmitters and hormones that transmit signals within the nervous system and endocrine system.

Examples of chemical stimulation include the use of medications, drugs, or supplements that affect mood, alertness, pain perception, or other bodily functions. For instance, caffeine can chemically stimulate the central nervous system to increase alertness and decrease feelings of fatigue. Similarly, certain painkillers can chemically stimulate opioid receptors in the brain to reduce the perception of pain.

It's important to note that while chemical stimulation can have therapeutic benefits, it can also have adverse effects if used improperly or in excessive amounts. Therefore, it's essential to follow proper dosing instructions and consult with a healthcare provider before using any chemical substances for stimulation purposes.

A Structure-Activity Relationship (SAR) in the context of medicinal chemistry and pharmacology refers to the relationship between the chemical structure of a drug or molecule and its biological activity or effect on a target protein, cell, or organism. SAR studies aim to identify patterns and correlations between structural features of a compound and its ability to interact with a specific biological target, leading to a desired therapeutic response or undesired side effects.

By analyzing the SAR, researchers can optimize the chemical structure of lead compounds to enhance their potency, selectivity, safety, and pharmacokinetic properties, ultimately guiding the design and development of novel drugs with improved efficacy and reduced toxicity.

Fluorescence Resonance Energy Transfer (FRET) is not strictly a medical term, but it is a fundamental concept in biophysical and molecular biology research, which can have medical applications. Here's the definition of FRET:

Fluorescence Resonance Energy Transfer (FRET) is a distance-dependent energy transfer process between two fluorophores, often referred to as a donor and an acceptor. The process occurs when the emission spectrum of the donor fluorophore overlaps with the excitation spectrum of the acceptor fluorophore. When the donor fluorophore is excited, it can transfer its energy to the acceptor fluorophore through non-radiative dipole-dipole coupling, resulting in the emission of light from the acceptor at a longer wavelength than that of the donor.

FRET efficiency depends on several factors, including the distance between the two fluorophores, their relative orientation, and the spectral overlap between their excitation and emission spectra. FRET is typically efficient when the distance between the donor and acceptor is less than 10 nm (nanometers), making it a powerful tool for measuring molecular interactions, conformational changes, and distances at the molecular level.

In medical research, FRET has been used to study various biological processes, such as protein-protein interactions, enzyme kinetics, and gene regulation. It can also be used in developing biosensors for detecting specific molecules or analytes in clinical samples, such as blood or tissue.

I believe there may be some confusion in your question as "Organic chemistry phenomena" is a broad term and not a medical definition. However, I can provide you with an explanation of organic chemistry phenomena in a general context.

Organic chemistry is the study of carbon-containing compounds, their synthesis, reactions, properties, and structures. The term "organic" was originally used to describe biological materials, but now it refers to any compound that contains carbon atoms bonded to hydrogen atoms, except for some simple oxides, sulfides, and halides.

Organic chemistry phenomena encompass a wide range of processes and events related to organic compounds. These can include:

1. Structural properties: Understanding the arrangement of atoms in organic molecules and how they influence chemical behavior and reactivity.
2. Stereochemistry: The study of three-dimensional spatial arrangements of atoms in organic molecules, which can significantly impact their properties and biological activity.
3. Functional groups: Recognizing and understanding the behavior of specific groupings of atoms within organic molecules that determine their chemical reactivity.
4. Reaction mechanisms: Investigating and describing the step-by-step processes by which organic reactions occur, including the movement of electrons, formation and breaking of bonds, and energy changes.
5. Synthetic methodologies: Developing strategies and techniques for creating complex organic molecules from simpler precursors, often involving multiple steps and protecting group strategies.
6. Physical properties: Examining how factors such as molecular weight, polarity, solubility, and melting/boiling points affect the behavior of organic compounds in various conditions.
7. Spectroscopic analysis: Utilizing techniques like NMR (Nuclear Magnetic Resonance), IR (Infrared) spectroscopy, and mass spectrometry to analyze the structure and composition of organic molecules.
8. Biochemistry and medicinal chemistry: Exploring how organic compounds interact with biological systems, including drug design, development, and delivery.

While not a medical definition per se, understanding organic chemistry phenomena is crucial for many areas within medicine, such as pharmaceutical research, toxicology, and biochemistry.

Adrenergic receptors are a type of G protein-coupled receptor that binds and responds to catecholamines, such as epinephrine (adrenaline) and norepinephrine (noradrenaline). Beta adrenergic receptors (β-adrenergic receptors) are a subtype of adrenergic receptors that include three distinct subclasses: β1, β2, and β3. These receptors are widely distributed throughout the body and play important roles in various physiological functions, including cardiovascular regulation, bronchodilation, lipolysis, and glucose metabolism.

β1-adrenergic receptors are primarily located in the heart and regulate cardiac contractility, chronotropy (heart rate), and relaxation. β2-adrenergic receptors are found in various tissues, including the lungs, vascular smooth muscle, liver, and skeletal muscle. They mediate bronchodilation, vasodilation, glycogenolysis, and lipolysis. β3-adrenergic receptors are mainly expressed in adipose tissue, where they stimulate lipolysis and thermogenesis.

Agonists of β-adrenergic receptors include catecholamines like epinephrine and norepinephrine, as well as synthetic drugs such as dobutamine (a β1-selective agonist) and albuterol (a non-selective β2-agonist). Antagonists of β-adrenergic receptors are commonly used in the treatment of various conditions, including hypertension, angina pectoris, heart failure, and asthma. Examples of β-blockers include metoprolol (a β1-selective antagonist) and carvedilol (a non-selective β-blocker with additional α1-adrenergic receptor blocking activity).

Indazoles are not a medical term, but a chemical classification. They refer to a class of heterocyclic organic compounds that contain a indazole moiety, which is a benzene ring fused with a diazole ring. Indazoles have no specific medical relevance, but certain derivatives of indazoles have been developed and used as drugs in medicine, particularly in the treatment of cancer and cardiovascular diseases. For example, Tadalafil (Cialis), a medication used to treat erectile dysfunction and benign prostatic hyperplasia, is a selective inhibitor of cGMP-specific phosphodiesterase type 5 and has an indazole structure.

Nitroglycerin, also known as glyceryl trinitrate, is a medication used primarily for the treatment of angina pectoris (chest pain due to coronary artery disease) and hypertensive emergencies (severe high blood pressure). It belongs to a class of drugs called nitrates or organic nitrites.

Nitroglycerin works by relaxing and dilating the smooth muscle in blood vessels, which leads to decreased workload on the heart and increased oxygen delivery to the myocardium (heart muscle). This results in reduced symptoms of angina and improved cardiac function during hypertensive emergencies.

The drug is available in various forms, including sublingual tablets, sprays, transdermal patches, ointments, and intravenous solutions. The choice of formulation depends on the specific clinical situation and patient needs. Common side effects of nitroglycerin include headache, dizziness, and hypotension (low blood pressure).

The heart ventricles are the two lower chambers of the heart that receive blood from the atria and pump it to the lungs or the rest of the body. The right ventricle pumps deoxygenated blood to the lungs, while the left ventricle pumps oxygenated blood to the rest of the body. Both ventricles have thick, muscular walls to generate the pressure necessary to pump blood through the circulatory system.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Gel chromatography is a type of liquid chromatography that separates molecules based on their size or molecular weight. It uses a stationary phase that consists of a gel matrix made up of cross-linked polymers, such as dextran, agarose, or polyacrylamide. The gel matrix contains pores of various sizes, which allow smaller molecules to penetrate deeper into the matrix while larger molecules are excluded.

In gel chromatography, a mixture of molecules is loaded onto the top of the gel column and eluted with a solvent that moves down the column by gravity or pressure. As the sample components move down the column, they interact with the gel matrix and get separated based on their size. Smaller molecules can enter the pores of the gel and take longer to elute, while larger molecules are excluded from the pores and elute more quickly.

Gel chromatography is commonly used to separate and purify proteins, nucleic acids, and other biomolecules based on their size and molecular weight. It is also used in the analysis of polymers, colloids, and other materials with a wide range of applications in chemistry, biology, and medicine.

The aorta is the largest artery in the human body, which originates from the left ventricle of the heart and carries oxygenated blood to the rest of the body. It can be divided into several parts, including the ascending aorta, aortic arch, and descending aorta. The ascending aorta gives rise to the coronary arteries that supply blood to the heart muscle. The aortic arch gives rise to the brachiocephalic, left common carotid, and left subclavian arteries, which supply blood to the head, neck, and upper extremities. The descending aorta travels through the thorax and abdomen, giving rise to various intercostal, visceral, and renal arteries that supply blood to the chest wall, organs, and kidneys.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

X-ray crystallography is a technique used in structural biology to determine the three-dimensional arrangement of atoms in a crystal lattice. In this method, a beam of X-rays is directed at a crystal and diffracts, or spreads out, into a pattern of spots called reflections. The intensity and angle of each reflection are measured and used to create an electron density map, which reveals the position and type of atoms in the crystal. This information can be used to determine the molecular structure of a compound, including its shape, size, and chemical bonds. X-ray crystallography is a powerful tool for understanding the structure and function of biological macromolecules such as proteins and nucleic acids.

'Bufo marinus' is the scientific name for a species of toad commonly known as the Cane Toad or Giant Toad. This toad is native to Central and South America, but has been introduced to various parts of the world including Florida, Australia, and several Pacific islands. The toad produces a toxic secretion from glands on its back and neck, which can be harmful or fatal if ingested by pets or humans.

Guanosine triphosphate (GTP) is a nucleotide that plays a crucial role in various cellular processes, such as protein synthesis, signal transduction, and regulation of enzymatic activities. It serves as an energy currency, similar to adenosine triphosphate (ATP), and undergoes hydrolysis to guanosine diphosphate (GDP) or guanosine monophosphate (GMP) to release energy required for these processes. GTP is also a precursor for the synthesis of other essential molecules, including RNA and certain signaling proteins. Additionally, it acts as a molecular switch in many intracellular signaling pathways by binding and activating specific GTPase proteins.

Bradykinin is a naturally occurring peptide in the human body, consisting of nine amino acids. It is a potent vasodilator and increases the permeability of blood vessels, causing a local inflammatory response. Bradykinin is formed from the breakdown of certain proteins, such as kininogen, by enzymes called kininases or proteases, including kallikrein. It plays a role in several physiological processes, including pain transmission, blood pressure regulation, and the immune response. In some pathological conditions, such as hereditary angioedema, bradykinin levels can increase excessively, leading to symptoms like swelling, redness, and pain.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.

E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.

Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.

Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.

Phosphoric monoester hydrolases are a class of enzymes that catalyze the hydrolysis of phosphoric monoesters into alcohol and phosphate. This class of enzymes includes several specific enzymes, such as phosphatases and nucleotidases, which play important roles in various biological processes, including metabolism, signal transduction, and regulation of cellular processes.

Phosphoric monoester hydrolases are classified under the EC number 3.1.3 by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB). The enzymes in this class share a common mechanism of action, which involves the nucleophilic attack on the phosphorus atom of the substrate by a serine or cysteine residue in the active site of the enzyme. This results in the formation of a covalent intermediate, which is then hydrolyzed to release the products.

Phosphoric monoester hydrolases are important therapeutic targets for the development of drugs that can modulate their activity. For example, inhibitors of phosphoric monoester hydrolases have been developed as potential treatments for various diseases, including cancer, neurodegenerative disorders, and infectious diseases.

Tissue distribution, in the context of pharmacology and toxicology, refers to the way that a drug or xenobiotic (a chemical substance found within an organism that is not naturally produced by or expected to be present within that organism) is distributed throughout the body's tissues after administration. It describes how much of the drug or xenobiotic can be found in various tissues and organs, and is influenced by factors such as blood flow, lipid solubility, protein binding, and the permeability of cell membranes. Understanding tissue distribution is important for predicting the potential effects of a drug or toxin on different parts of the body, and for designing drugs with improved safety and efficacy profiles.

Guanine nucleotides are molecules that play a crucial role in intracellular signaling, cellular regulation, and various biological processes within cells. They consist of a guanine base, a sugar (ribose or deoxyribose), and one or more phosphate groups. The most common guanine nucleotides are GDP (guanosine diphosphate) and GTP (guanosine triphosphate).

GTP is hydrolyzed to GDP and inorganic phosphate by certain enzymes called GTPases, releasing energy that drives various cellular functions such as protein synthesis, signal transduction, vesicle transport, and cell division. On the other hand, GDP can be rephosphorylated back to GTP by nucleotide diphosphate kinases, allowing for the recycling of these molecules within the cell.

In addition to their role in signaling and regulation, guanine nucleotides also serve as building blocks for RNA (ribonucleic acid) synthesis during transcription, where they pair with cytosine nucleotides via hydrogen bonds to form base pairs in the resulting RNA molecule.

A conserved sequence in the context of molecular biology refers to a pattern of nucleotides (in DNA or RNA) or amino acids (in proteins) that has remained relatively unchanged over evolutionary time. These sequences are often functionally important and are highly conserved across different species, indicating strong selection pressure against changes in these regions.

In the case of protein-coding genes, the corresponding amino acid sequence is deduced from the DNA sequence through the genetic code. Conserved sequences in proteins may indicate structurally or functionally important regions, such as active sites or binding sites, that are critical for the protein's activity. Similarly, conserved non-coding sequences in DNA may represent regulatory elements that control gene expression.

Identifying conserved sequences can be useful for inferring evolutionary relationships between species and for predicting the function of unknown genes or proteins.

Inosine triphosphate (ITP) is not a medical condition, but rather a biochemical compound that plays a role in the body's energy metabolism and nucleic acid synthesis. It is an ester of inosine and triphosphoric acid. ITP can be produced from adenosine triphosphate (ATP) by the action of enzymes such as adenylate kinase or nucleoside diphosphate kinase, and it can also be degraded back to inosine monophosphate (IMP) by the enzyme ITP pyrophosphatase.

In certain disease states, such as some types of anemia, there may be an accumulation of ITP due to impaired breakdown. However, ITP is not typically used as a diagnostic or clinical marker in these conditions.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

Calcimycin is a ionophore compound that is produced by the bacterium Streptomyces chartreusensis. It is also known as Calcineurin A inhibitor because it can bind to and inhibit the activity of calcineurin, a protein phosphatase. In medical research, calcimycin is often used to study calcium signaling in cells.
It has been also used in laboratory studies for its antiproliferative and pro-apoptotic effects on certain types of cancer cells. However, it is not approved for use as a drug in humans.

Thionucleotides are chemical compounds that are analogs of nucleotides, which are the building blocks of DNA and RNA. In thionucleotides, one or more of the oxygen atoms in the nucleotide's chemical structure is replaced by a sulfur atom. This modification can affect the way the thionucleotide interacts with other molecules, including enzymes that work with nucleotides and nucleic acids.

Thionucleotides are sometimes used in research to study the biochemistry of nucleic acids and their interactions with other molecules. They can also be used as inhibitors of certain enzymes, such as reverse transcriptase, which is an important target for HIV/AIDS therapy. However, thionucleotides are not normally found in natural biological systems and are not themselves components of DNA or RNA.

Biofilms are defined as complex communities of microorganisms, such as bacteria and fungi, that adhere to surfaces and are enclosed in a matrix made up of extracellular polymeric substances (EPS). The EPS matrix is composed of polysaccharides, proteins, DNA, and other molecules that provide structural support and protection to the microorganisms within.

Biofilms can form on both living and non-living surfaces, including medical devices, implants, and biological tissues. They are resistant to antibiotics, disinfectants, and host immune responses, making them difficult to eradicate and a significant cause of persistent infections. Biofilms have been implicated in a wide range of medical conditions, including chronic wounds, urinary tract infections, middle ear infections, and device-related infections.

The formation of biofilms typically involves several stages, including initial attachment, microcolony formation, maturation, and dispersion. Understanding the mechanisms underlying biofilm formation and development is crucial for developing effective strategies to prevent and treat biofilm-associated infections.

Smooth muscle, also known as involuntary muscle, is a type of muscle that is controlled by the autonomic nervous system and functions without conscious effort. These muscles are found in the walls of hollow organs such as the stomach, intestines, bladder, and blood vessels, as well as in the eyes, skin, and other areas of the body.

Smooth muscle fibers are shorter and narrower than skeletal muscle fibers and do not have striations or sarcomeres, which give skeletal muscle its striped appearance. Smooth muscle is controlled by the autonomic nervous system through the release of neurotransmitters such as acetylcholine and norepinephrine, which bind to receptors on the smooth muscle cells and cause them to contract or relax.

Smooth muscle plays an important role in many physiological processes, including digestion, circulation, respiration, and elimination. It can also contribute to various medical conditions, such as hypertension, gastrointestinal disorders, and genitourinary dysfunction, when it becomes overactive or underactive.

High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.

In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.

HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.

Transducin is a G protein found in the rod cells of the retina and plays a crucial role in the visual signal transduction pathway. It is responsible for converting the light-induced isomerization of rhodopsin into a biochemical signal, which ultimately leads to the activation of downstream effectors and the generation of a neural response.

Transducin has three subunits: alpha (Tα), beta (Tβ), and gamma (Tγ). When light activates rhodopsin, it interacts with the Tα subunit, causing it to exchange GDP for GTP and dissociate from the Tβγ complex. The activated Tα then interacts with a downstream effector called phosphodiesterase (PDE), which leads to the hydrolysis of cGMP and the closure of cGMP-gated ion channels in the plasma membrane. This results in the hyperpolarization of the rod cell, which is the initial step in the visual signal transduction pathway.

Overall, transducin is a key player in the conversion of light energy into neural signals, allowing us to see and perceive our visual world.

Complementary DNA (cDNA) is a type of DNA that is synthesized from a single-stranded RNA molecule through the process of reverse transcription. In this process, the enzyme reverse transcriptase uses an RNA molecule as a template to synthesize a complementary DNA strand. The resulting cDNA is therefore complementary to the original RNA molecule and is a copy of its coding sequence, but it does not contain non-coding regions such as introns that are present in genomic DNA.

Complementary DNA is often used in molecular biology research to study gene expression, protein function, and other genetic phenomena. For example, cDNA can be used to create cDNA libraries, which are collections of cloned cDNA fragments that represent the expressed genes in a particular cell type or tissue. These libraries can then be screened for specific genes or gene products of interest. Additionally, cDNA can be used to produce recombinant proteins in heterologous expression systems, allowing researchers to study the structure and function of proteins that may be difficult to express or purify from their native sources.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

A lung is a pair of spongy, elastic organs in the chest that work together to enable breathing. They are responsible for taking in oxygen and expelling carbon dioxide through the process of respiration. The left lung has two lobes, while the right lung has three lobes. The lungs are protected by the ribcage and are covered by a double-layered membrane called the pleura. The trachea divides into two bronchi, which further divide into smaller bronchioles, leading to millions of tiny air sacs called alveoli, where the exchange of gases occurs.

Vasodilation is the widening or increase in diameter of blood vessels, particularly the involuntary relaxation of the smooth muscle in the tunica media (middle layer) of the arteriole walls. This results in an increase in blood flow and a decrease in vascular resistance. Vasodilation can occur due to various physiological and pathophysiological stimuli, such as local metabolic demands, neural signals, or pharmacological agents. It plays a crucial role in regulating blood pressure, tissue perfusion, and thermoregulation.

Calcium channels, L-type, are a type of voltage-gated calcium channel that are widely expressed in many excitable cells, including cardiac and skeletal muscle cells, as well as certain neurons. These channels play a crucial role in the regulation of various cellular functions, such as excitation-contraction coupling, hormone secretion, and gene expression.

L-type calcium channels are composed of five subunits: alpha-1, alpha-2, beta, gamma, and delta. The alpha-1 subunit is the pore-forming subunit that contains the voltage sensor and the selectivity filter for calcium ions. It has four repeated domains (I-IV), each containing six transmembrane segments (S1-S6). The S4 segment in each domain functions as a voltage sensor, moving outward upon membrane depolarization to open the channel and allow calcium ions to flow into the cell.

L-type calcium channels are activated by membrane depolarization and have a relatively slow activation and inactivation time course. They are also modulated by various intracellular signaling molecules, such as protein kinases and G proteins. L-type calcium channel blockers, such as nifedipine and verapamil, are commonly used in the treatment of hypertension, angina, and certain cardiac arrhythmias.

Amino acid oxidoreductases are a class of enzymes that catalyze the reversible oxidation and reduction reactions involving amino acids. They play a crucial role in the metabolism of amino acids by catalyzing the interconversion of L-amino acids to their corresponding α-keto acids, while simultaneously reducing a cofactor such as NAD(P)+ or FAD.

The reaction catalyzed by these enzymes can be represented as follows:

L-amino acid + H2O + Coenzyme (Oxidized) → α-keto acid + NH3 + Coenzyme (Reduced)

Amino acid oxidoreductases are classified into two main types based on their cofactor requirements and reaction mechanisms. The first type uses FAD as a cofactor and is called amino acid flavoprotein oxidoreductases. These enzymes typically catalyze the oxidative deamination of L-amino acids to form α-keto acids, ammonia, and reduced FAD. The second type uses pyridine nucleotides (NAD(P)+) as cofactors and is called amino acid pyridine nucleotide-dependent oxidoreductases. These enzymes catalyze the reversible interconversion of L-amino acids to their corresponding α-keto acids, while simultaneously reducing or oxidizing NAD(P)H/NAD(P)+.

Amino acid oxidoreductases are widely distributed in nature and play important roles in various biological processes, including amino acid catabolism, nitrogen metabolism, and the biosynthesis of various secondary metabolites. Dysregulation of these enzymes has been implicated in several diseases, including neurodegenerative disorders and cancer. Therefore, understanding the structure, function, and regulation of amino acid oxidoreductases is crucial for developing novel therapeutic strategies to treat these diseases.

Cromakalim is a pharmacological agent, specifically a potassium channel opener, that was investigated for its potential therapeutic effects in the treatment of cardiovascular diseases such as hypertension and angina. Potassium channel openers work by relaxing smooth muscle cells in blood vessels, which leads to vasodilation and decreased blood pressure. However, cromakalim was never approved for clinical use due to its associated side effects, including negative inotropic effects on the heart and potential proarrhythmic properties.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

COS cells are a type of cell line that are commonly used in molecular biology and genetic research. The name "COS" is an acronym for "CV-1 in Origin," as these cells were originally derived from the African green monkey kidney cell line CV-1. COS cells have been modified through genetic engineering to express high levels of a protein called SV40 large T antigen, which allows them to efficiently take up and replicate exogenous DNA.

There are several different types of COS cells that are commonly used in research, including COS-1, COS-3, and COS-7 cells. These cells are widely used for the production of recombinant proteins, as well as for studies of gene expression, protein localization, and signal transduction.

It is important to note that while COS cells have been a valuable tool in scientific research, they are not without their limitations. For example, because they are derived from monkey kidney cells, there may be differences in the way that human genes are expressed or regulated in these cells compared to human cells. Additionally, because COS cells express SV40 large T antigen, they may have altered cell cycle regulation and other phenotypic changes that could affect experimental results. Therefore, it is important to carefully consider the choice of cell line when designing experiments and interpreting results.

Oxyhemoglobin is the form of hemoglobin that is combined with oxygen in red blood cells. It's created when oxygen molecules bind to the iron-containing heme groups of the hemoglobin protein inside the lungs, allowing for the transportation of oxygen from the lungs to body tissues. The affinity of hemoglobin for oxygen is influenced by factors such as pH, carbon dioxide concentration, and temperature, which can affect the release of oxygen from oxyhemoglobin in different parts of the body based on their specific needs.

Methacholine compounds are medications that are used as a diagnostic tool to help identify and confirm the presence of airway hyperresponsiveness in patients with respiratory symptoms such as cough, wheeze, or shortness of breath. These compounds act as bronchoconstrictors, causing narrowing of the airways in individuals who have heightened sensitivity and reactivity of their airways, such as those with asthma.

Methacholine is a synthetic derivative of acetylcholine, a neurotransmitter that mediates nerve impulse transmission in the body. When inhaled, methacholine binds to muscarinic receptors on the smooth muscle surrounding the airways, leading to their contraction and narrowing. The degree of bronchoconstriction is then measured to assess the patient's airway responsiveness.

It is important to note that methacholine compounds are not used as therapeutic agents but rather as diagnostic tools in a controlled medical setting under the supervision of healthcare professionals.

The penis is a part of the male reproductive and urinary systems. It has three parts: the root, the body, and the glans. The root attaches to the pelvic bone and the body makes up the majority of the free-hanging portion. The glans is the cone-shaped end that protects the urethra, the tube inside the penis that carries urine from the bladder and semen from the testicles.

The penis has a dual function - it acts as a conduit for both urine and semen. During sexual arousal, the penis becomes erect when blood fills two chambers inside its shaft. This process is facilitated by the relaxation of the smooth muscles in the arterial walls and the trappping of blood in the corpora cavernosa. The stiffness of the penis enables sexual intercourse. After ejaculation, or when the sexual arousal passes, the muscles contract and the blood flows out of the penis back into the body, causing it to become flaccid again.

The foreskin, a layer of skin that covers the glans, is sometimes removed in a procedure called circumcision. Circumcision is often performed for religious or cultural reasons, or as a matter of family custom. In some countries, it's also done for medical reasons, such as to treat conditions like phimosis (an inability to retract the foreskin) or balanitis (inflammation of the glans).

It's important to note that any changes in appearance, size, or function of the penis should be evaluated by a healthcare professional, as they could indicate an underlying medical condition.

Protoveratrines are a group of toxic compounds found in the plant species Veratrum album (white hellebore). These compounds include protoveratrine A and protoveratrine B, which can cause severe cardiovascular and neurological symptoms when ingested or otherwise introduced into the body. They act as alkaloids that disrupt the functioning of sodium channels in cell membranes, leading to a range of adverse effects such as bradycardia (slow heart rate), hypotension (low blood pressure), respiratory depression, and neurological symptoms like paralysis, convulsions, and coma.

It is important to note that white hellebore and its extracts, including protoveratrines, have been used in traditional medicine for various purposes, such as treating heart conditions and reducing fever. However, due to their high toxicity and narrow therapeutic index, they are not commonly used in modern medical practice. Instead, safer and more effective alternatives are preferred.

Histamine is defined as a biogenic amine that is widely distributed throughout the body and is involved in various physiological functions. It is derived primarily from the amino acid histidine by the action of histidine decarboxylase. Histamine is stored in granules (along with heparin and proteases) within mast cells and basophils, and is released upon stimulation or degranulation of these cells.

Once released into the tissues and circulation, histamine exerts a wide range of pharmacological actions through its interaction with four types of G protein-coupled receptors (H1, H2, H3, and H4 receptors). Histamine's effects are diverse and include modulation of immune responses, contraction and relaxation of smooth muscle, increased vascular permeability, stimulation of gastric acid secretion, and regulation of neurotransmission.

Histamine is also a potent mediator of allergic reactions and inflammation, causing symptoms such as itching, sneezing, runny nose, and wheezing. Antihistamines are commonly used to block the actions of histamine at H1 receptors, providing relief from these symptoms.

... phosphate phosphodiesterase, cyclic GMP phosphodiesterase, cyclic 3′,5′-GMP phosphodiesterase, cyclic guanosine 3′,5′- ... Cyclic AMP and cyclic GMP phosphodiesterase". Biochim. Biophys. Acta. 334: 368-377. doi:10.1016/0005-2744(74)90180-6. Portal: ... cyclic-GMP phosphodiesterase (EC 3.1.4.35) catalyzes the reaction guanosine 3′,5′-cyclic phosphate + H2O ⇌ {\displaystyle \ ... phosphate phosphodiesterase, cGMP phosphodiesterase, cGMP-PDE, and cyclic guanosine 3′,5′-phosphate phosphodiesterase. As of ...
... cyclic-AMP and -GMP phosphodiesterase 11A is an enzyme that in humans is encoded by the PDE11A gene. The 3',5'-cyclic ... Yuasa K, Ohgaru T, Asahina M, Omori K (2001). "Identification of rat cyclic nucleotide phosphodiesterase 11A (PDE11A): ... Beavo JA, Conti M, Heaslip RJ (1994). "Multiple cyclic nucleotide phosphodiesterases". Mol. Pharmacol. 46 (3): 399-405. PMID ... cyclic nucleotide phosphodiesterase 11A: localization in human tissues". Int. J. Impot. Res. 17 (4): 320-5. doi:10.1038/sj.ijir ...
1975). "Biologic regulation through opposing influences of cyclic GMP and cyclic AMP: the Yin Yang hypothesis". Adv Cyclic ... June 1997). "cGMP-stimulated cyclic nucleotide phosphodiesterase regulates the basal calcium current in human atrial myocytes ... Bender AT, Beavo JA (September 2006). "Cyclic nucleotide phosphodiesterases: molecular regulation to clinical use". Pharmacol. ... The PDE2 (phosphodiesterase 2) enzyme is one of 21 different phosphodiesterases (PDE) found in mammals. These different PDEs ...
... cyclic di-GMP). Degradation of cyclic di-GMP to guanosine monophosphate (GMP) is catalyzed by a phosphodiesterase (PDE). ... Cyclic di-GMP binds to interface between the DGC and D2 domains stabilizing the open structure and preventing catalysis. Strong ... Often, GGDEF domains with DGC activity are found in the same proteins as c-di-GMP-specific phosphodiesterase (PDE) EAL (Glu-Ala ... Jenal U, Malone J (2006). "Mechanisms of cyclic-di-GMP signaling in bacteria". Annual Review of Genetics. 40: 385-407. doi: ...
Numerous cyclic nucleotide phosphodiesterases (PDE) can degrade cGMP by hydrolyzing cGMP into 5'-GMP. PDE 5, -6 and -9 are cGMP ... Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second ... cyclic monophosphate (8-Br-cGMP) Francis SH, Corbin JD (August 1999). "Cyclic nucleotide-dependent protein kinases: ... Phosphodiesterase inhibitors prevent the degradation of cGMP, thereby enhancing and/or prolonging its effects. For example, ...
... cyclic-GMP phosphodiesterase MeSH D08.811.277.352.640.150 - 3',5'-cyclic-nucleotide phosphodiesterase MeSH D08.811.277.352. ... cyclic gmp-dependent protein kinases MeSH D08.811.913.696.620.682.700.150.575 - protamine kinase MeSH D08.811.913.696.620.682. ... cyclic-nucleotide phosphodiesterases MeSH D08.811.277.352.640.295 - glycerophosphoinositol inositolphosphodiesterase MeSH ... cyclic nucleotide-regulated protein kinases MeSH D08.811.913.696.620.682.700.150.125 - cyclic amp-dependent protein kinases ...
Linari M, Hanzal-Bayer M, Becker J (Sep 1999). "The delta subunit of rod specific cyclic GMP phosphodiesterase, PDE delta, ... interacts with the delta subunit of rod cyclic GMP phosphodiesterase". Proceedings of the National Academy of Sciences of the ... interacts with the delta subunit of rod cyclic GMP phosphodiesterase". Proceedings of the National Academy of Sciences of the ... cyclic phosphodiesterase subunit delta is an enzyme that in humans is encoded by the PDE6D gene. PDE6D was originally ...
In mammals, GAF domains are found in five members of the cyclic nucleotide phosphodiesterase superfamily: PDE2, PDE5, and PDE6 ... a ubiquitous signaling motif and a new class of cyclic GMP receptor". The EMBO Journal. 19 (20): 5288-99. doi:10.1093/emboj/ ... The GAF domain is named after some of the proteins it is found in: cGMP-specific phosphodiesterases, adenylyl cyclases and FhlA ... "The two GAF domains in phosphodiesterase 2A have distinct roles in dimerization and in cGMP binding". Proceedings of the ...
Nitric oxide and cyclic GMP in cell signaling and drug development". The New England Journal of Medicine. 355 (19): 2003-11. ... Phosphodiesterase type 5 (PDE5), which is abundant in the pulmonary tissue, hydrolyzes the cyclic bond of cGMP. Consequently, ... s The U.S. FDA approved sildenafil, a selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5), for the treatment ... Levels of cAMP (which mediates most of the biological effects of prostacyclin) are reduced by phosphodiesterases 3 and 4. The ...
Organization of the gene for the beta-subunit of human photoreceptor cyclic GMP phosphodiesterase]". Bioorganicheskaia Khimiia ... "In vivo differential prenylation of retinal cyclic GMP phosphodiesterase catalytic subunits". The Journal of Biological ... "Enzymic basis for cyclic GMP accumulation in degenerative photoreceptor cells of mouse retina". Journal of Cyclic Nucleotide ... cyclic phosphodiesterase subunit beta is the beta subunit of the protein complex PDE6 that is encoded by the PDE6B gene. PDE6 ...
The two most well-studied cyclic nucleotides are cyclic AMP (cAMP) and cyclic GMP (cGMP), while cyclic CMP (cCMP) and cyclic ... cAMP's role in this process terminates upon hydrolysis to AMP by phosphodiesterase. Cyclic nucleotides are well-suited to act ... Lincoln, TM; Cornwell TL (1991). "Towards an understanding of the mechanism of action of cyclic AMP and cyclic GMP in smooth ... As can be seen in the cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) images, the 'cyclic' ...
Cyclic GMP-AMP (cGAMP) is a cyclic dinucleotide (CDN) and the first to be found in metazoans. Other CDNs (c-di-GMP and c-di-AMP ... phosphodiesterases. Other advantages of the unique 2'-5' linkage may be that cGAMP is able to bind multiple allelic variants of ... Upon binding DNA, the protein cyclic GMP-AMP Synthase (cGAS) triggers reaction of GTP and ATP to form cyclic GMP-AMP (cGAMP). ... specifically by the cyclic-GMP-AMP synthase (cGAS). Upon DNA recognition, cGAS dimerizes and stimulates the formation of cyclic ...
... inhibition with BAY 73-6691 increases corpus cavernosum relaxations mediated by nitric oxide-cyclic GMP pathway in mice". ... Effects of phosphodiesterase 10 inhibition on striatal cyclic AMP and peripheral physiology in rats; An Torremans, Abdellah ... 2001). "Cyclic nucleotide phosphodiesterases". The Journal of Allergy and Clinical Immunology. 108 (5): 671-80. doi:10.1067/mai ... A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), ...
... for instance a bond in a molecule of cyclic AMP or cyclic GMP. An enzyme that plays an important role in the repair of ... Phosphodiesterase Phosphodiesterase inhibitor DNA replication, DNA, ATP Teichoic acid, DNase I PDE5 Nick (DNA) "Phosphodiester ... A phosphodiesterase is an enzyme that catalyzes the hydrolysis of phosphodiester bonds, ... Hydrolysis of phosphodiester bonds is catalyzed by phosphodiesterases, which are involved in repairing DNA sequences. The ...
... c-di-GMP-specific phosphodiesterase, c-di-GMP phosphodiesterase, phosphodiesterase, phosphodiesterase A1, PDEA1, VieA) is an ... Cyclic-guanylate-specific phosphodiesterase (EC 3.1.4.52, cyclic bis(3′→5')diguanylate phosphodiesterase, ... "Identification and characterization of a cyclic di-GMP-specific phosphodiesterase and its allosteric control by GTP". J. Biol. ... Cyclic-guanylate-specific+phosphodiesterase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: ...
Kroll S, Phillips WJ, Cerione RA (March 1989). "The regulation of the cyclic GMP phosphodiesterase by the GDP-bound form of the ... cyclic-nucleotide phosphodiesterases (EC 3.1.4.17) are a family of phosphodiesterases. Generally, these enzymes hydrolyze a ... monophosphate phosphodiesterase (cyclic CMP), cyclic 3′,5-nucleotide monophosphate phosphodiesterase, nucleoside 3′,5′-cyclic ... cyclic-nucleotide phosphodiesterases in rod cells are oligomeric, made up of two heavy catalytic subunits, α (90 kDa) and β (85 ...
"Localization of the human gene for the type I cyclic GMP-dependent protein kinase to chromosome 10". Cytogenetics and Cell ... and kinase-directed regulation of phosphorylation of a cGMP-binding phosphodiesterase by cGMP". The Journal of Biological ... 27 (3 Pt 2): 552-7. doi:10.1161/01.hyp.27.3.552. PMID 8613202. Salih E, Zhou HY, Glimcher MJ (Jul 1996). "Phosphorylation of ... 96 (5): 2467-72. Bibcode:1999PNAS...96.2467E. doi:10.1073/pnas.96.5.2467. PMC 26808. PMID 10051666. Wang X, Bruderer S, Rafi Z ...
... protects cyclic guanosine monophosphate (cGMP) from degradation by cGMP-specific phosphodiesterase type 5 (PDE5) in ... Phosphodiesterase inhibitors (e.g., sildenafil) can also improve [Raynaud's phenomenon] symptoms and ulcer healing Nieto ... Laties AM (January 2009). "Vision disorders and phosphodiesterase type 5 inhibitors: a review of the evidence to date". Drug ... Sildenafil acts by blocking phosphodiesterase 5 (PDE5), an enzyme that promotes breakdown of cGMP, which regulates blood flow ...
... interacts with the delta subunit of rod cyclic GMP phosphodiesterase". Proceedings of the National Academy of Sciences of the ... interacts with the delta subunit of rod cyclic GMP phosphodiesterase". Proceedings of the National Academy of Sciences of the ... 38 (13): 2750-5. PMID 9418727. Yan D, Swain PK, Breuer D, Tucker RM, Wu W, Fujita R, Rehemtulla A, Burke D, Swaroop A (Jul 1998 ... 5 (7): 1035-41. doi:10.1093/hmg/5.7.1035. PMID 8817343. Murga-Zamalloa CA, Atkins SJ, Peranen J, Swaroop A, Khanna H (Sep 2010 ...
Cyclic GMP binds to the cGMP-dependent protein kinase (PKG1) which phosphorylates several proteins that results in decreased ... Lugnier, C. (2006). "Cyclic nucleotide phosphodiesterase (PDE) superfamily: A new target for the development of specific ... Their function is to degrade intracellular second messengers such as cyclic adenine monophosphate (cAMP) and cyclic guanosine ... GMP is an inactive molecule with no second messenger activity. Phosphorylation of a single serine by PKG1 and the allosteric ...
... cyclic-GMP-forming)) is a lyase enzyme that converts guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP) and ... Once formed, cGMP can be degraded by phosphodiesterases, which themselves are under different forms of regulation, depending on ... cyclic GMP + diphosphate It is often part of the G protein signaling cascade that is activated by low intracellular calcium ... Adenylyl cyclase Cyclic guanosine monophosphate Guanylyl cyclase activator (protein) Martin, Emil; Berka, Vladimir; Tsai, Ah‐ ...
... reducing cyclic GMP degradation. Endothelin receptor antagonist, another class of drugs used in PAH "Prescription medicines: ... Nitrates and phosphodiesterase inhibitors (including PDE5 inhibitors) increase the hypotensive (blood pressure lowering) effect ... NO binds to soluble guanylate cyclase (sGC) and mediates the synthesis of the secondary messenger cyclic guanosine ... Therefore, the concomitant use of riociguat with phosphodiesterase-5 inhibitors is contraindicated. Cinaciguat, a sGC activator ...
... cyclic phosphodiesterase subunit alpha is an enzyme that in humans is encoded by the PDE6A gene. PDE6A encodes the cyclic-GMP ( ... cGMP) specific phosphodiesterase 6A alpha subunit, expressed in cells of the retinal rod outer segment. The phosphodiesterase 6 ... "Cryo-EM structure of phosphodiesterase 6 reveals insights into the allosteric regulation of type I phosphodiesterases". Science ... "Entrez Gene: PDE6A phosphodiesterase 6A, cGMP-specific, rod, alpha". Gulati S, Palczewski K, Engel A, Stahlberg H, Kovacik L ( ...
... cyclic-GMP phosphodiesterase EC 3.1.4.36: Now with EC 3.1.4.43 EC 3.1.4.37: 2′,3′-cyclic-nucleotide 3'-phosphodiesterase EC 3.1 ... phosphodiesterase * EC 3.1.4.59: cyclic-di-AMP phosphodiesterase * EC 3.1.4.60: pApA phosphodiesterase * EC 3.1.4.61: cyclic 2, ... CMP-N-acylneuraminate phosphodiesterase EC 3.1.4.41: sphingomyelin phosphodiesterase D EC 3.1.4.42: glycerol-1,2-cyclic- ... cyclic phosphate phosphodiesterase EC 3.1.4.57: phosphoribosyl 1,2-cyclic phosphate 1,2-diphosphodiesterase * EC 3.1.4.58: RNA ...
Linari M, Hanzal-Bayer M, Becker J (1999). "The delta subunit of rod specific cyclic GMP phosphodiesterase, PDE delta, ... 377 (6547 Suppl): 3-174. PMID 7566098. Andersson B, Wentland MA, Ricafrente JY, Liu W, Gibbs RA (1996). "A "double adaptor" ... 17 (5): 2476-87. doi:10.1091/mbc.E05-10-0929. PMC 1446103. PMID 16525022. v t e (Articles with short description, Short ... ADP-ribosylation factor-like protein 3 is a protein that in humans is encoded by the ARL3 gene. ADP-ribosylation factor-like 3 ...
"Physical and genetic localization of the gamma subunit of the cyclic GMP phosphodiesterase on the long arm of chromosome 17 ( ... The organization of the gamma-subunit gene of human photoreceptor cyclic GMP phosphodiesterase]" [The organization of the gamma ... of patients with retinitis pigmentosa using a cloned cDNA probe for the human gamma subunit of cyclic GMP phosphodiesterase". ... gene of human photoreceptor cyclic GMP phosphodiesterase]. Doklady Akademii Nauk SSSR. 315 (1): 229-31. PMID 1965799. Tuteja N ...
... but an inhibition of the enzyme phosphodiesterase causing elevation of cyclic AMP and cyclic GMP[clarification needed] levels ... Papaverine has also been demonstrated to be a selective phosphodiesterase inhibitor for the PDE10A subtype found mainly in the ... August 2006). "Inhibition of the striatum-enriched phosphodiesterase PDE10A: a novel approach to the treatment of psychosis". ... Hebb AL, Robertson HA, Denovan-Wright EM (May 2008). "Phosphodiesterase 10A inhibition is associated with locomotor and ...
... inhibition with BAY 73-6691 increases corpus cavernosum relaxations mediated by nitric oxide-cyclic GMP pathway in mice". ... A phosphodiesterase (PDE) is an enzyme that breaks a phosphodiester bond. Usually, phosphodiesterase refers to cyclic ... "Ontogenetic development of a phosphodiesterase activator and the multiple forms of cyclic AMP phosphodiesterase of rat brain". ... "Differential activation and inhibition of the multiple forms of cyclic nucleotide phosphodiesterase". Advances in Cyclic ...
... cyclic guanosine monophosphate (cGMP), guanosine pentaphosphate ((p)ppGpp), and cyclic di-GMP (c-di-GMP). c-di-AMP is a ... Phosphodiesterase (PDE) enzymes degrade cyclic di-AMP to the linear molecule 5'-pApA (phosphadenylyl adenosine). 5'-pApA is ... Cyclic di-GMP Dey B, Dey RJ, Cheung LS, Pokkali S, Guo H, Lee JH, Bishai WR (April 2015). "A bacterial cyclic dinucleotide ... December 2012). "The helicase DDX41 recognizes the bacterial secondary messengers cyclic di-GMP and cyclic di-AMP to activate a ...
... which stimulates the synthesis of cyclic guanosine monophosphate (more commonly known as cyclic GMP or cGMP) in smooth muscle ... In 1993, the Bothell, Washington, biotechnology company ICOS Corporation began studying compound IC351, a phosphodiesterase ... The inhibition of phosphodiesterase type 5 (PDE5) enhances erectile function by increasing the amount of cGMP.[medical citation ... "Risk of nonarteritic ischaemic optic neuropathy with phosphodiesterase type 5 inhibitors: a systematic review and meta-analysis ...
... phosphate phosphodiesterase, cyclic GMP phosphodiesterase, cyclic 3′,5′-GMP phosphodiesterase, cyclic guanosine 3′,5′- ... Cyclic AMP and cyclic GMP phosphodiesterase". Biochim. Biophys. Acta. 334: 368-377. doi:10.1016/0005-2744(74)90180-6. Portal: ... cyclic-GMP phosphodiesterase (EC 3.1.4.35) catalyzes the reaction guanosine 3′,5′-cyclic phosphate + H2O ⇌ {\displaystyle \ ... phosphate phosphodiesterase, cGMP phosphodiesterase, cGMP-PDE, and cyclic guanosine 3′,5′-phosphate phosphodiesterase. As of ...
Cyclic-GMP Phosphodiesterases" by people in Profiles.. * Zhang L, Zhang Z, Zhang RL, Cui Y, LaPointe MC, Silver B, Chopp M. ... Cyclic-GMP Phosphodiesterases" by people in this website by year, and whether "3,5-Cyclic-GMP Phosphodiesterases" was a major ... Cyclic-GMP Phosphodiesterases" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH ( ... Enzymes that catalyze the hydrolysis of cyclic GMP to yield guanosine-5-phosphate. ...
... the amplified binding of GTP to transducin molecules which then activate cyclic GMP phosphodiesterase. Electrophysiologists ... the amplified binding of GTP to transducin molecules which then activate cyclic GMP phosphodiesterase. Electrophysiologists ... and that light-induced hydrolysis of cyclic GMP leads to closure of the channels and therefore to hyperpolarization of the rod ... recently have shown that cyclic GMP keeps ion channels in the plasma membrane of the rod outer segment open in darkness, ...
Cyclic-GMP Phosphodiesterases * Arrhythmias, Cardiac / chemically induced* * Cyclic Nucleotide Phosphodiesterases, Type 5 ... 2003 May;41(5):734-43. doi: 10.1097/00005344-200305000-00010. Authors Bodo Cremers 1 , Marina Scheler, Christoph Maack, Olaf ... Sildenafil (0.0001-10 microM) neither in human atrium (n = 12) nor in failing (n = 8) or nonfailing (n = 5) ventricle exerted a ...
Cyclic-GMP Phosphodiesterase Catalysis, Chemical reaction, Enzyme substrate (biology), Hydrolase, Ester, Biomolecular structure ...
Cyclic-GMP Phosphodiesterase Catalysis, Chemical reaction, Enzyme substrate (biology), Hydrolase, Ester, Biomolecular structure ...
... cyclic-di-GMP promotes biofilm formation while it is controlled by two groups of enzymes, phosphodiesterase (PDE) for its ... Cyclic-Di-GMP Expression Assay. Overnight cultures of the cyclic-di-GMP reporter strains were diluted to OD600nm 0.01 in ABTGC ... As cdrA is positively regulated by cyclic-di-GMP, overexpression of cdrA reflects an increase in cyclic-di-GMP biosynthesis ( ... cdrA::gfp reporter assay confirmed the excessive production of cyclic-di-GMP in both LYSZa7 and LYSZa8 (Figure 1B). Such cyclic ...
... cyclic-AMP and -GMP phosphodiesterase 11A(Homo sapiens (Human)). Schering-Plough Research Institute. Curated by ChEMBL. ... cyclic-AMP and -GMP phosphodiesterase 11A (PDE11A1) 35-489] 1. *High affinity cGMP-specific 3,5-cyclic phosphodiesterase 9A [ ... cyclic-AMP and -GMP phosphodiesterase 11A 5. *Dual specificity calcium/calmodulin-dependent 3,5-cyclic nucleotide ... cyclic-AMP and -GMP phosphodiesterase 11A (PDE11A1) 35-489](Homo sapiens (Human)). Plexxikon. ...
Cyclic nucleotide turnover/signalling C *Adenylyl cyclases (ACs) C. *Cyclic GMP-AMP synthase ... Exchange protein activated by cyclic AMP (EPACs) C. *Phosphodiesterases, 3,5-cyclic nucleotide (PDEs) C ... Type I PIP kinases (1-phosphatidylinositol-4-phosphate 5-kinase family). *Type II PIP kinases (1-phosphatidylinositol-5- ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
Cyclic-GMP Phosphodiesterase. 3,5-Cyclic-GMP Phosphodiesterases. 3,5-Cyclic-Nucleotide Phosphodiesterase. 3,5-Cyclic-AMP ...
... cyclic-GMP phosphodiesterase activity IBA Inferred from Biological aspect of Ancestor. more info ... cyclic phosphodiesterase subunit alpha. Names. cGMP phosphodiesterase 6C. phosphodiesterase 6C, cGMP-specific, cone, alpha ... cyclic-GMP phosphodiesterase activity IEA Inferred from Electronic Annotation. more info ... GAF; Domain present in phytochromes and cGMP-specific phosphodiesterases. pfam00233. Location:561 → 806. PDEase_I; 35-cyclic ...
Nitric oxide signaling in pseudomonas aeruginosa biofilms mediates phosphodiesterase activity, decreased cyclic Di-GMP levels, ... Formation and dimerization of the phosphodiesterase active site of the Pseudomonas aeruginosa MorA, a bi-functional c-di-GMP ... Changes in metal coordination are required to regulate activity of bacterial phosphodiesterases, implicated in c-di-GMP ... In S-H. Chou, N. Guiliani, V. Lee, & U. Römling (Eds.), Microbial Cyclic Di-Nucleotide Signaling (1 ed., pp. 27-48). Springer, ...
This list of 582 genes contains 12 proteases and 3 antiproteases. We found that ... cyclic-AMP and -GMP phosphodiesterase 11A" would have a role in signal transduction (Table 1). The last constituent of this ... cyclic-AMP and -GMP phosphodiesterase 11A" (GeneID:424133, 24-fold increase) and "PREDICTED: nebulin-related-anchoring protein ... Table 5 Antiproteases identified in the egg yolk [[14],[15]] and the vitelline membrane (VM) [[30]]. Full size table. ...
... cyclic-AMP and #NAME? phosphodiesterase 11A isoform X2 XM_045033997.1. XP_044889932.1. dual 3,5-cyclic-AMP and #NAME? ... GMP-grade Proteins. Animal-free Recombinant Proteins. 重组蛋白定制. 定制合成服务. ADC 相关定制服务. PROTAC 相关定制服务. ... cyclic-AMP and #NAME? phosphodiesterase 11A isoform X1 XM_045033996.1. XP_044889931.1. dual 3,5-cyclic-AMP and #NAME? ... GMP Small Molecules. 诱导疾病模型产品. 标准品. ... GMP-grade ProteinsGMP 级
In another group of experiments, l-citrulline was shown to increase intracellular cyclic GMP levels from 2.1 ± 0.2 pmol of cGMP ... Zaprinast, a phosphodiesterase type V inhibitor, enhanced 5-bromo-2′-deoxyuridine incorporation in serum-stimulated cells. ... receptor and the production of cyclic GMP. In a previous study, we demonstrated thatl-citrulline, the by-product of nitric ... 5-Bromo-2′-deoxyuridine incorporation into nuclei of vehicle-treated cells was 40.5 ± 2.4%, whereas inl-citrulline-treated ...
Cyclic-GMP Phosphodiesterases. *Activating Transcription Factor 6. *Adaptor Proteins, Signal Transducing ...
Lee MR, Li L, Kitazawa T. Cyclic GMP causes Ca2+ desensitization in vascular smooth muscle by activating the myosin light chain ... Moreland RB, Goldestein I, Kim NN, Traish A. Sildenafil citrate, a selective phosphodiesterase type 5 inhibitor: research and ... Ignarro LJ, Bush PA, Buga GM, Wood KS, Fukuto JM, Rajfer J. Nitric oxide and cyclic GMP formation upon electrical field ... The hydrolysis of cGMP by phosphodiesterase type 5 (PDE 5) leads to a corpus cavernosum contraction (103, 108, 111-116). ...
Schultz, C., Vaskinn, S., Kildalsen, H. and Sager, G. (1998) Cyclic AMP Stimulates the Cyclic GMP Egression Pump in Human ... Francis, S.H., Sekhar, K.R., Ke, H. and Corbin, J.D. (2011) Inhibition of Cyclic Nucleotide Phosphodiesterases by ... Pilz, R.B. and Broderick, K.E. (2005) Role of Cyclic GMP in Gene Regulation. Frontiers in Bioscience, 10, 1239-1268. ... Kariya, K., Kawahara, Y., Araki, S., Fukuzaki, H. and Takai, Y. (1989) Antiproliferative Action of Cyclic GMP-Elevating ...
Cyclic GMP signaling in cardiovascular pathophysiology and therapeutics. Pharmacol Ther 2009; 122: 216-238. ... Change from baseline (the last documented value while still receiving phosphodiesterase-5 inhibitor) in N-terminal prohormone ... Change from baseline (the last documented value while still receiving phosphodiesterase-5 inhibitor) in 6-min walking distance ... Change in haemodynamics from baseline (the last documented value while still receiving phosphodiesterase-5 inhibitor) to week ...
... cyclic-GMP phosphodiesterase activity GO:0047555 * phosphoserine phosphatase activity GO:0004647 ...
  • A proportion of pulmonary arterial hypertension (PAH) patients do not reach treatment goals with phosphodiesterase-5 inhibitors (PDE5i). (ersjournals.com)
  • 2. Benau D., Szabo E.I., Terner C. Endogenous inhibitors of cyclic adenosine 3',5'-monophosphate-phosphodiesterase in rat epididymis. (abvpress.ru)
  • Tadalafil in pills is phosphodiesterase type 5 inhibitors. (cheapgenericeddrug.co)
  • Selective phosphodiesterase (PDE) inhibitors improve the formation of hippocampus-dependent memories in several rodent models of cognition. (springer.com)
  • 2005 ). cAMP and cGMP are hydrolyzed by phosphodiesterase (PDE) enzymes, and inhibitors of PDEs (PDE-Is) produce cognition-enhancing effects in animal models of cognition. (springer.com)
  • Inhibitors of phosphodiesterase-5 (PDE 5 ) are a class of drug that were originally developed as anti-ischaemic agents based on their ability to overexpress the nitric oxide (NO) pathway pursued via cyclic guanosine monophosphate (cGMP) signalling. (ecrjournal.com)
  • Accordingly, over the last few years the use of PDE 5 inhibitors has been expanded to the therapeutic management of some cardiovascular disorders, including heart failure (HF). (ecrjournal.com)
  • Among all PDEs, PDE 5 , which is inhibited by sildenafil and other inhibitors of clinical use, has been widely investigated. (ecrjournal.com)
  • Sildenafil (Viagra), vardenafil (Levitra) and tadanafil (Cialis) are the three specific PDE 5 inhibitors in current clinical use, 5 which, despite similar although not identical mechanisms of action and structural similarity, present some significant differences regarding potency and selectivity. (ecrjournal.com)
  • Medications such as phosphodiesterase-5 inhibitors(Viagra): sildenafil, vardenafil, tadalafil, and avanafil, are all phosphodiesterase (PDE-5) inhibitors. (sexualhealthformenpodcast.com)
  • All four PDE-5 inhibitors enhance penile muscles the corpus cavernosum cyclic GMP levels. (sexualhealthformenpodcast.com)
  • These medications can cause low blood pressure and impaired ejaculations when used with phosphodiesterase -5-inhibitors. (sexualhealthformenpodcast.com)
  • Garg, U.C. and Hassid, A. (1989) Nitric Oxide-Generating Vasodilators and 8-Bromo-cyclic Guanosine Monophosphate Inhibit Mitogenesis and Proliferation of Cultured Rat Vascular Smooth Muscle Cells. (scirp.org)
  • CIALIS® (tadalafil), an oral treatment for erectile dysfunction, is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). (theodora.com)
  • The continuous influx of sodium ions results from binding of cyclic guanosine monophosphate (cGMP) to the sodium gates, which keeps the gated channels open while maintaining neurotransmitter release onto the bipolar cell, hyperpolarizing it (ie, the bipolar cells are inhibited). (medscape.com)
  • The activated G-protein activates cGMP phosphodiesterase, which catalyzes the conversion of cGMP to guanosine monophosphate (GMP). (medscape.com)
  • The enzyme 3′,5′-cyclic-GMP phosphodiesterase (EC 3.1.4.35) catalyzes the reaction guanosine 3′,5′-cyclic phosphate + H2O ⇌ {\displaystyle \rightleftharpoons } guanosine 5′-phosphate This enzyme belongs to the family of hydrolases, specifically those acting on phosphoric diester bonds. (wikipedia.org)
  • NO is formed from L-arginine via the enzyme nitric oxide synthase or synthetase (NOS), and the effects of NO are mainly mediated by 3,'5' -cyclic guanylate or cyclic GMP. (herbstoreusa.com)
  • NO activates the enzyme guanylate cyclase, which catalyzes the synthesis of cyclic GMP from guanosine triphosphate or GTP. (herbstoreusa.com)
  • Cyclic GMP is converted to guanylic acid via the enzyme cyclic GMP phosphodiesterase. (herbstoreusa.com)
  • The PDE6H gene provides instructions for making one part (called the inhibitory gamma subunit) of an enzyme called cone-specific phosphodiesterase. (medlineplus.gov)
  • Specifically, the enzyme converts a molecule called cGMP to another molecule, 5'-GMP, in cones. (medlineplus.gov)
  • The enzyme Cyclic GMP widens blood vessels in the penile by relaxing a thin layer of muscle that is mainly found in the blood vessel walls. (cheapgenericeddrug.co)
  • PDE 5 comprises an enzyme superfamily with 11 subfamilies that hydrolyse the phosphodiester bond of cGMP and cyclic adenosine monophosphate (cAMP) to form the inactive 5'-GMP and 5'-AMP. (ecrjournal.com)
  • Zhang L, Zhang Z, Zhang RL, Cui Y, LaPointe MC, Silver B, Chopp M. Tadalafil, a long-acting type 5 phosphodiesterase isoenzyme inhibitor, improves neurological functional recovery in a rat model of embolic stroke. (umassmed.edu)
  • Phosphodiesterase inhibitor-mediated potentiation of adenovirus delivery to myocardium. (umassmed.edu)
  • Zaprinast, a phosphodiesterase type V inhibitor, enhanced 5-bromo-2′-deoxyuridine incorporation in serum-stimulated cells. (aspetjournals.org)
  • The interaction with the non-selective PDE (cyclic nucleotide phosphodiesterase) inhibitor 3-isobutyl-1-methylxanthine (IBMX) was tested after three days. (scirp.org)
  • A phosphodiesterase 5 inhibitor used to treat erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension. (drugbank.com)
  • The 8-nitro-cGMP-induced relaxation in db/db mouse aortas was found to be resistant to a phosphodiesterase 5 inhibitor, zaprinast (1 μM). (elsevierpure.com)
  • Use of tadalafil tablets with alpha-blockers, antihypertensives or substantial amounts of alcohol (≥5 units) may lead to hypotension ( 5.6 , 5.9 ). (nih.gov)
  • Tadalafil has the empirical formula C 22 H 19 N 3 O 4 representing a molecular weight of 389.41. (theodora.com)
  • In vitro studies have shown that the effect of tadalafil is more potent on PDE5 than on other phosphodiesterases. (theodora.com)
  • 6 in the rat aorta, vardenafil but not sildenafil or tadalafil affects serum calcium (Ca++) handling to produce relaxation in addition to the typical increase of cGMP mediated by PDE 5 inhibition. (ecrjournal.com)
  • 0.001) down-regulated the oxidative stress causing reduction in PDE-5 activity followed by the decrease in 5'GMP and ET-1 levels, resulting into significant increase in NO synthesis due to the accelerated eNOS phosphorylation compared to tadalafil. (heraldopenaccess.us)
  • Apart from this, SPR and docking results have also confirmed the better association of quercetin with PDE-5 compared to tadalafil. (heraldopenaccess.us)
  • The percentage of inhibition exerted by l -citrulline on days 3, 5, and 7 of the proliferation curve was 20.0 ± 0.5%, 37.5 ± 8.3%, and 28.5 ± 7.2%, respectively. (aspetjournals.org)
  • Moreover, l -citrulline inhibition of serum-stimulated DNA synthesis was abolished by HS-142-1 (10 −5 M), an ANP receptor antagonist. (aspetjournals.org)
  • The inhibition of phosphodiesterase type 5 (PDE5) enhances erectile function by increasing the amount of cGMP. (theodora.com)
  • This gene encodes the alpha-prime subunit of cone phosphodiesterase, which is composed of a homodimer of two alpha-prime subunits and 3 smaller proteins of 11, 13, and 15 kDa. (nih.gov)
  • This change prevents the production of any functional inhibitory gamma subunit, which interferes with the normal function of cone-specific phosphodiesterase. (medlineplus.gov)
  • Cyclic GMP causes smooth muscle relaxation and increased blood flow into the corpus cavernosum. (theodora.com)
  • Rats injected with a saffron extract were found to have increased intracellular cyclic GMP (cGMP) concentrations in their corpus cavernosum. (naturalmedicinejournal.com)
  • Enzymes that catalyze the hydrolysis of cyclic GMP to yield guanosine-5'-phosphate. (umassmed.edu)
  • Electrophysiologists recently have shown that cyclic GMP keeps ion channels in the plasma membrane of the rod outer segment open in darkness, and that light-induced hydrolysis of cyclic GMP leads to closure of the channels and therefore to hyperpolarization of the rod cell. (nih.gov)
  • synthesized by GGDEF domain-containing diguanylate cyclases and degraded by HD-GYP domain-containing phosphodiesterases (PDEs) to 2 GMP or by EAL domain-containing PDE-As to 5′-phosphoguanylyl-(3′,5′)-guanosine (pGpG). (knoblauchpublishing.com)
  • Much additional work by our group and others' is now elucidating the nitric oxide and c-di-GMP-mediated signalling pathway, and its exploitation for biofilm control in medical and industrial contexts. (southampton.ac.uk)
  • BACKGROUND AND PURPOSE: 8-Nitroguanosine 3′,5′-cyclic monophosphate (8-nitro-cGMP), formed nitric oxide (NO)-dependently, is a physiological second messenger, yet little is known about its role in the pathophysiology of vascular diseases. (elsevierpure.com)
  • Vasoconstriction primarily results from endothelial dysfunctioning due to imbalanced bioavailability of dilators especially- Nitric Oxide (NO) and Prostacyclin Analogs (PGI2) vs elevation in constrictors such as- thromboxane, Angiotensin II (Ang II), Endothelin-1 (ET-1) [5]. (heraldopenaccess.us)
  • Cyclic GMP elevates nitric oxide levels which then promotes an erection in response to sexual stimulation. (sexualhealthformenpodcast.com)
  • Bronchoconstriction, a state of bronchial smooth muscle tone is modulated by the interactions of the beta-adrenergic receptors and the metabolism of the intracellular cyclic nucleotides. (biomedcentral.com)
  • The principal process by which intracellular cAMP levels are reduced is via hydrolysis by the phosphodiesterase enzymes. (biomedcentral.com)
  • Nitrate represses production of an important biofilm component, curli, and activates flagella via the modulation of intracellular cyclic-di-GMP levels. (knoblauchpublishing.com)
  • Despite an improved understanding of how c-di-GMP signaling regulates S. Typhimurium biofilms, the processes that affect the intracellular c-di-GMP levels and the formation of multicellular communities in vivo during infections remain unknown. (knoblauchpublishing.com)
  • Finally, we propose that PggH could modulate the activities of PDE-As and the intracellular concentration of c-di-GMP, resulting in phenotypic changes including in biofilm formation. (knoblauchpublishing.com)
  • Chen, Z.S., Lee, K. and Kruh, G.D. (2001) Transport of Cyclic Nucleotides and Estradiol 17-Beta-d-glucuronide by Multidrug Resistance Protein 4. (scirp.org)
  • Bronchiolar obstruction, which causes airway obstruction in hyperresponsive airways, often results from the contraction of the airway's smooth muscles, increased viscid mucous secretions, and mucosal oedema consequent upon a reduced cyclic 3,5-adenosine monophosphate (c-AMP). (biomedcentral.com)
  • 3. Razzaboni B., Terner C. Cyclic adenosine 3',5'-monophosphate-phosphodiesterases in epididymis and prostate of castrate and of aged rats. (abvpress.ru)
  • 6. Mewe M., Bauer C.K., Müller D., Middendorff R. Regulation of spontaneous contractile activity in the bovine epididymal duct by cyclic guanosine 5'-monophosphate-dependent pathways. (abvpress.ru)
  • The major metabolites 3,5,6-trichloro-2-pyridinol (TCP) and 2-hydroxy pyridine were identified during CP degradation by RNC3 whereas, only TCP by RNC7 using GC-MS. Key enzymes encoded by opd and opch2 genes were annotated in the genomes of RNC3 and RNC7 along with the set of putative degradation genes (tcp, yieH, pho, prp). (bvsalud.org)
  • A phosphatidylinositol 3-kinase subclass that includes enzymes whose specificity is limited to 1-phosphatidylinositol. (rush.edu)
  • 2 The substrate specificities include enzymes that are specific for cyclic AMP hydrolysis, enzymes for cyclic GMP hydrolysis 3 and those that hydrolyse both. (ecrjournal.com)
  • Cyclic GMP-AMP synthase (cGAS) senses foreign DNA to produce 2'3′-cyclic GMP-AMP (2'3′-cGAMP). (knoblauchpublishing.com)
  • Photoactivated rhodopsin (R) catalyses, by repetitively interacting with many copies of a guanosine nucleotide binding protein (transducin), the amplified binding of GTP to transducin molecules which then activate cyclic GMP phosphodiesterase. (nih.gov)
  • and an abundant soluble protein of 48 KDal (called 48 K-protein, S-antigen, or arrestin) that specifically binds to phosphorylated R. Phosphorylation partially suppresses the ability of R to catalyze transducin-mediated phosphodiesterase activation even in the absence of arrestin. (nih.gov)
  • Pharmacology & Pharmacy , 5 , 262-271. (scirp.org)
  • The production of estrogen and at a lower magnitude testosterone by the theca of the growing follicle increases 2 to 3 weeks before the production of the first egg and contributes to the development of reproductive organs and the synthesis of egg constituents [ 1 - 6 ]. (biomedcentral.com)
  • In addition, l -citrulline also inhibited serum-induced DNA synthesis, measured as 5-bromo-2′-deoxyuridine incorporation. (aspetjournals.org)
  • Sildenafil, although very selective for PDE 5 , shows some cross-reactivity with PDE 6 , which is predominant in photoreceptors 8 and may transiently disturb colour vision perception in individuals taking high doses of sildenafil. (ecrjournal.com)
  • An antidepressant agent used for the treatment of major depressive disorder that targets the 5-HT transporter and 5-HT1A receptors. (drugbank.com)
  • Cone-specific phosphodiesterase carries out one of the reactions in this process. (medlineplus.gov)
  • Shimizu-Matsumoto A, Itoh K, Inazawa J, Nishida K, Matsumoto Y, Kinoshita S, Matsubara K, Okubo K. Isolation and chromosomal localization of the human cone cGMP phosphodiesterase gamma cDNA (PDE6H). (medlineplus.gov)
  • A serotonin 5-HT3 receptor antagonist used to prevent nausea and vomiting in cancer chemotherapy and postoperatively. (drugbank.com)
  • Sildenafil (0.0001-10 microM) neither in human atrium (n = 12) nor in failing (n = 8) or nonfailing (n = 5) ventricle exerted a significant inotropic response. (nih.gov)
  • Rolipram (0.003-0.03 mg/kg, intramuscular [i.m.]) and sildenafil (0.3-3 mg/kg, i.m.) dose-dependently increased correct first reaches during difficult trials, reaching significance at 0.01 and 1 mg/kg, respectively. (springer.com)
  • This graph shows the total number of publications written about "Class III Phosphatidylinositol 3-Kinases" by people in this website by year, and whether "Class III Phosphatidylinositol 3-Kinases" was a major or minor topic of these publications. (rush.edu)
  • Below are the most recent publications written about "Class III Phosphatidylinositol 3-Kinases" by people in Profiles. (rush.edu)
  • Phosphotransferases that catalyzes the conversion of 1-phosphatidylinositol to 1-phosphatidylinositol 3-phosphate. (nih.gov)
  • Phosphatidylinositol 3-Kinases have been classified both according to their substrate specificity and their mode of action within the cell. (nih.gov)
  • RNC3 and RNC7 showed 82.5 mgL-1 and 77.1 mgL-1 CP degradation within 5 days. (bvsalud.org)
  • This main active ingredient in the medicine works sensationally by preventing action of a chemical in the body called phosphodiesterase type 5. (cheapgenericeddrug.co)
  • Quorum sensing is a type of bacterial communication that occurs via the secretion of autoinducer molecules (5). (kenyon.edu)
  • The A 3 isoform is located in tissues having cardiac or smooth muscle constituents, such as the heart, bladder, prostate, urethra, penis, uterus and skeletal muscle. (ecrjournal.com)
  • Pilz, R.B. and Broderick, K.E. (2005) Role of Cyclic GMP in Gene Regulation. (scirp.org)
  • Further, the compatibility of the drugs (analytes) toward PDE-5 (ligand) was ascertained by SPR spectroscopy and molecular docking. (heraldopenaccess.us)
  • A 5HT-3 receptor antagonist used as an antiemetic in the treatment of chemotherapy-induced nausea and vomiting. (drugbank.com)
  • 3',5'-Cyclic-GMP Phosphodiesterases" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (umassmed.edu)
  • Steady-state plasma concentrations are attained within 5 days of once-daily dosing, and exposure is approximately 1.6-fold greater than after a single dose. (theodora.com)
  • A member of the triptan class of 5-HT(1B/1D/1F) receptor agonist drugs used for the acute treatment of migraine with or without aura in adults. (drugbank.com)
  • Cyclic GMP was able to mimic the antiproliferative effect of SNP on HEK293 cells. (scirp.org)
  • This list of 582 genes contains 12 proteases and 3 antiproteases. (biomedcentral.com)
  • 7. Swinnen J.V., Joseph D.R., Conti M. Molecular cloning of rat homologues of the Drosophila melanogaster dunce cAMP phosphodiesterase: evidence for a family of genes. (abvpress.ru)
  • This study examined the efficacy of quercetin in preventing the hypoxia-mediated increase in Phosphodiesterase-5 (PDE-5) levels in the lung, leading to the diminution of alveolar smooth muscles vasoconstriction and curtailed transvascular leakage. (heraldopenaccess.us)
  • Research had also confirmed that exacerbation in ROS production due to hypoxia is amongst major factors for the occurrence of vasoconstriction in the smooth muscles of lung endothelium [5,6]. (heraldopenaccess.us)
  • Partition w into its four quadrants w0, w1, Леонов ВА (1975) Клинико-рентгенологическая характеристика рака желудка у лиц молодого возраста (Clin- ical and X-ray symptoms of gastric cancer in the 299 10 targeted specifically to adipocytes, are the β3-adreno- ceptor agonists such as the first generation compound BRL-37344 [(RR SS)-()-4-[2-(2-(3-chlorophenyl)- 2-hydroxyethyl)amino)propyl] phenoxyacetate]. (banglaforexacademy.com)
  • 9 Another cross-reactivity is that found with PDE 11 , which may be responsible for the development of back pain and myalgia as side effects of tadanafil due to the low selectivity of the compound for PDE 5 over PDE 11 . (ecrjournal.com)
  • When cGMP (1000 μM) was added to the cell culture medium for 5 days the cell densities were reduced with 37% below baseline and cGMP in increased from 5.3 to 195 pmol/10 7 cells. (scirp.org)
  • Cyclic AMP also controls the clearance of the airway mucus by modulating the ciliary beat frequency [ 6 ] and suppresses the pro-inflammatory activities of the body's immune and inflammatory cells. (biomedcentral.com)
  • It can be difficult to detect the presence of V. cholerae in water sources, due to the bacterium's ability to aggregate into of conditionally viable environmental cells (CVECs) (3). (kenyon.edu)
  • Increase to 20 mg or decrease to 5 mg based upon efficacy/tolerability. (nih.gov)
  • May increase to 5 mg based upon efficacy and tolerability ( 2.2 ). (nih.gov)
  • Once inside, it activated adenyl cyclase, causing the concentration of cyclic-AMP to increase. (kenyon.edu)
  • For example, important zinc metalloenzymes include alkaline phosphatase, RNA polymerases, and alcohol dehydrogenase ( 3 ). (frontiersin.org)
  • Since excess pGpG feedback inhibits PDE-A activity and thereby can lead to the uncontrolled accumulation of c-di-GMP, a PDE that degrades pGpG to 2 GMP (PDE-B) has been presumed to exist. (knoblauchpublishing.com)
  • Evidence for androgen-dependent phosphodiesterase activity in rat seminal vesicle and epididymis. (abvpress.ru)
  • However, later on the clinical applicability of the enhanced NO/cGMP pathway in terms of inhibiting PDE 5 activity was felt to be more relevant than previously thought. (ecrjournal.com)