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.
Drugs that selectively bind to and activate beta-adrenergic receptors.
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.
A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.
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.
An enzyme of the lyase class that catalyzes the formation of CYCLIC AMP and pyrophosphate from ATP. EC 4.6.1.1.
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.
Cell-surface proteins that bind epinephrine and/or norepinephrine with high affinity and trigger intracellular changes. The two major classes of adrenergic receptors, alpha and beta, were originally discriminated based on their cellular actions but now are distinguished by their relative affinity for characteristic synthetic ligands. Adrenergic receptors may also be classified according to the subtypes of G-proteins with which they bind; this scheme does not respect the alpha-beta distinction.
Drugs that mimic the effects of stimulating postganglionic adrenergic sympathetic nerves. Included here are drugs that directly stimulate adrenergic receptors and drugs that act indirectly by provoking the release of adrenergic transmitters.
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.
Contractile activity of the MYOCARDIUM.
A subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The adrenergic beta-2 receptors are more sensitive to EPINEPHRINE than to NOREPINEPHRINE and have a high affinity for the agonist TERBUTALINE. They are widespread, with clinically important roles in SKELETAL MUSCLE; LIVER; and vascular, bronchial, gastrointestinal, and genitourinary SMOOTH MUSCLE.
The largest of the three pairs of SALIVARY GLANDS. They lie on the sides of the FACE immediately below and in front of the EAR.
Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.
Hydrogenated alprenolol derivative where the extra hydrogens are often tritiated. This radiolabeled form of ALPRENOLOL, a beta-adrenergic blocker, is used to label the beta-adrenergic receptor for isolation and study.
A subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The adrenergic beta-1 receptors are equally sensitive to EPINEPHRINE and NOREPINEPHRINE and bind the agonist DOBUTAMINE and the antagonist METOPROLOL with high affinity. They are found in the HEART, juxtaglomerular cells, and in the central and peripheral nervous systems.
Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).
A moderately lipophilic beta blocker (ADRENERGIC BETA-ANTAGONISTS). It is non-cardioselective and has intrinsic sympathomimetic actions, but little membrane-stabilizing activity. (From Martindale, The Extra Pharmocopoeia, 30th ed, p638)
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)
A highly selective and specific beta antagonist that is used to characterize beta-adrenoceptors.
The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.
Drugs that bind to and activate adrenergic receptors.
AMINO ALCOHOLS containing the propanolamine (NH2CH2CHOHCH2) group and its derivatives.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
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.
One of the ADRENERGIC BETA-ANTAGONISTS used as an antihypertensive, anti-anginal, and anti-arrhythmic agent.
An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.
A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
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.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
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.
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
Drugs that selectively bind to and activate alpha adrenergic receptors.
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.
A family of heterotrimeric GTP-binding protein alpha subunits that activate ADENYLYL CYCLASES.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
Compounds that bind to and activate ADRENERGIC BETA-1 RECEPTORS.
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 relationship between the dose of an administered drug and the response of the organism to the drug.
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 nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.
Enlargement of the HEART, usually indicated by a cardiothoracic ratio above 0.50. Heart enlargement may involve the right, the left, or both HEART VENTRICLES or HEART ATRIA. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (HEART FAILURE) or several forms of CARDIOMYOPATHIES.
A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.
The metabolic process of breaking down LIPIDS to release FREE FATTY ACIDS, the major oxidative fuel for the body. Lipolysis may involve dietary lipids in the DIGESTIVE TRACT, circulating lipids in the BLOOD, and stored lipids in the ADIPOSE TISSUE or the LIVER. A number of enzymes are involved in such lipid hydrolysis, such as LIPASE and LIPOPROTEIN LIPASE from various tissues.
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.
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 subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The beta-3 adrenergic receptors are the predominant beta-adrenergic receptor type expressed in white and brown ADIPOCYTES and are involved in modulating ENERGY METABOLISM and THERMOGENESIS.
Diphenylacetic acids are organic compounds characterized by a structure containing two phenyl groups (aromatic rings) bonded to an acetic acid group, which have been used in pharmaceuticals and research due to their anti-inflammatory, antifungal, and muscle relaxant properties.
One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation.
Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.
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.
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.
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.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.
Protein domains that are enriched in PROLINE. The cyclical nature of proline causes the peptide bonds it forms to have a limited degree of conformational mobility. Therefore the presence of multiple prolines in close proximity to each other can convey a distinct conformational arrangement to a peptide chain.
The rate dynamics in chemical or physical systems.
An ENTEROTOXIN from VIBRIO CHOLERAE. It consists of two major protomers, the heavy (H) or A subunit and the B protomer which consists of 5 light (L) or B subunits. The catalytic A subunit is proteolytically cleaved into fragments A1 and A2. The A1 fragment is a MONO(ADP-RIBOSE) TRANSFERASE. The B protomer binds cholera toxin to intestinal epithelial cells, and facilitates the uptake of the A1 fragment. The A1 catalyzed transfer of ADP-RIBOSE to the alpha subunits of heterotrimeric G PROTEINS activates the production of CYCLIC AMP. Increased levels of cyclic AMP are thought to modulate release of fluid and electrolytes from intestinal crypt cells.
The hemodynamic and electrophysiological action of the HEART VENTRICLES.
Compounds bind to and activate ADRENERGIC BETA-2 RECEPTORS.
The chambers of the heart, to which the BLOOD returns from the circulation.
Treatment process involving the injection of fluid into an organ or tissue.
Drugs that bind to and block the activation of ADRENERGIC BETA-2 RECEPTORS.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
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.
A source of inorganic fluoride which is used topically to prevent dental caries.
An alpha-1 adrenergic agonist that causes prolonged peripheral VASOCONSTRICTION.
That phase of a muscle twitch during which a muscle returns to a resting position.
Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
A non-hydrolyzable analog of GTP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It binds tightly to G-protein in the presence of Mg2+. The nucleotide is a potent stimulator of ADENYLYL CYCLASES.
A drug combination that contains THEOPHYLLINE and ethylenediamine. It is more soluble in water than theophylline but has similar pharmacologic actions. It's most common use is in bronchial asthma, but it has been investigated for several other applications.
A network of tubules and sacs in the cytoplasm of SKELETAL MUSCLE FIBERS that assist with muscle contraction and relaxation by releasing and storing calcium ions.
Elements of limited time intervals, contributing to particular results or situations.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Compounds that bind to and activate ADRENERGIC BETA-3 RECEPTORS.
Drugs that bind to and block the activation of ADRENERGIC BETA-1 RECEPTORS.
A group of amylolytic enzymes that cleave starch, glycogen, and related alpha-1,4-glucans. (Stedman, 25th ed) EC 3.2.1.-.
Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.
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.
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.
A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)
A cardioselective beta-1 adrenergic blocker possessing properties and potency similar to PROPRANOLOL, but without a negative inotropic effect.
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)
(11 alpha,13E,15S)-11,15-Dihydroxy-9-oxoprost-13-en-1-oic acid (PGE(1)); (5Z,11 alpha,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-dien-1-oic acid (PGE(2)); and (5Z,11 alpha,13E,15S,17Z)-11,15-dihydroxy-9-oxoprosta-5,13,17-trien-1-oic acid (PGE(3)). Three of the six naturally occurring prostaglandins. They are considered primary in that no one is derived from another in living organisms. Originally isolated from sheep seminal fluid and vesicles, they are found in many organs and tissues and play a major role in mediating various physiological activities.
Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.
A non-hydrolyzed muscarinic agonist used as a research tool.
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.
A potent vasodilator agent that increases peripheral blood flow.
A beta-2 selective adrenergic antagonist. It is used primarily in animal and tissue experiments to characterize BETA-2 ANDRENERGIC RECEPTORS.
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 family of heterotrimeric GTP-binding protein alpha subunits that were originally identified by their ability to inhibit ADENYLYL CYCLASES. Members of this family can couple to beta and gamma G-protein subunits that activate POTASSIUM CHANNELS. The Gi-Go part of the name is also spelled Gi/Go.
LIPOLYSIS of stored LIPIDS in the ADIPOSE TISSUE to release FREE FATTY ACIDS. Mobilization of stored lipids is under the regulation of lipolytic signals (CATECHOLAMINES) or anti-lipolytic signals (INSULIN) via their actions on the hormone-sensitive LIPASE. This concept does not include lipid transport.
Large woodland game BIRDS in the subfamily Meleagridinae, family Phasianidae, order GALLIFORMES. Formerly they were considered a distinct family, Melegrididae.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
AMINO ALCOHOLS containing the ETHANOLAMINE; (-NH2CH2CHOH) group and its derivatives.
One of two salivary glands in the neck, located in the space bound by the two bellies of the digastric muscle and the angle of the mandible. It discharges through the submandibular duct. The secretory units are predominantly serous although a few mucous alveoli, some with serous demilunes, occur. (Stedman, 25th ed)
Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.
Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.
A long-acting beta-2-adrenergic receptor agonist.
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.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Cells in the body that store FATS, usually in the form of TRIGLYCERIDES. WHITE ADIPOCYTES are the predominant type and found mostly in the abdominal cavity and subcutaneous tissue. BROWN ADIPOCYTES are thermogenic cells that can be found in newborns of some species and hibernating mammals.
A selective adrenergic alpha-1 antagonist used in the treatment of HEART FAILURE; HYPERTENSION; PHEOCHROMOCYTOMA; RAYNAUD DISEASE; PROSTATIC HYPERTROPHY; and URINARY RETENTION.
Drugs that inhibit the actions of the sympathetic nervous system by any mechanism. The most common of these are the ADRENERGIC ANTAGONISTS and drugs that deplete norepinephrine or reduce the release of transmitters from adrenergic postganglionic terminals (see ADRENERGIC AGENTS). Drugs that act in the central nervous system to reduce sympathetic activity (e.g., centrally acting alpha-2 adrenergic agonists, see ADRENERGIC ALPHA-AGONISTS) are included here.
A specific subtype of muscarinic receptor found in the lower BRAIN, the HEART and in SMOOTH MUSCLE-containing organs. Although present in smooth muscle the M2 muscarinic receptor appears not to be involved in contractile responses.
Proteins and peptides found in SALIVA and the SALIVARY GLANDS. Some salivary proteins such as ALPHA-AMYLASES are enzymes, but their composition varies in different individuals.
The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).
An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
A transient loss of consciousness and postural tone caused by diminished blood flow to the brain (i.e., BRAIN ISCHEMIA). Presyncope refers to the sensation of lightheadedness and loss of strength that precedes a syncopal event or accompanies an incomplete syncope. (From Adams et al., Principles of Neurology, 6th ed, pp367-9)
Drugs that act on adrenergic receptors or affect the life cycle of adrenergic transmitters. Included here are adrenergic agonists and antagonists and agents that affect the synthesis, storage, uptake, metabolism, or release of adrenergic transmitters.
The decrease 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.
Nucleotides in which the base moiety is substituted with one or more sulfur atoms.
Drugs used to cause dilation of the blood vessels.
A group of compounds that are derivatives of beta-methylacetylcholine (methacholine).
A set of BACTERIAL ADHESINS and TOXINS, BIOLOGICAL produced by BORDETELLA organisms that determine the pathogenesis of BORDETELLA INFECTIONS, such as WHOOPING COUGH. They include filamentous hemagglutinin; FIMBRIAE PROTEINS; pertactin; PERTUSSIS TOXIN; ADENYLATE CYCLASE TOXIN; dermonecrotic toxin; tracheal cytotoxin; Bordetella LIPOPOLYSACCHARIDES; and tracheal colonization factor.
Drugs that bind to but do not activate ADRENERGIC RECEPTORS. Adrenergic antagonists block the actions of the endogenous adrenergic transmitters EPINEPHRINE and NOREPINEPHRINE.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
One of the virulence factors produced by BORDETELLA PERTUSSIS. It is a multimeric protein composed of five subunits S1 - S5. S1 contains mono ADPribose transferase activity.
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)
A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
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.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
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.
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.
A beta-1 adrenergic antagonist that has been used in the emergency treatment of CARDIAC ARRYTHMIAS.
A mixture of three different hydrogenated derivatives of ERGOTAMINE: DIHYDROERGOCORNINE; DIHYDROERGOCRISTINE; and DIHYDROERGOCRYPTINE. Dihydroergotoxine has been proposed to be a neuroprotective agent and a nootropic agent. The mechanism of its therapeutic actions is not clear, but it can act as an alpha-adrenergic antagonist and a dopamine agonist. The methanesulfonate salts of this mixture of alkaloids are called ERGOLOID MESYLATES.

Automatic activity in depolarized guinea pig ventricular myocardium. Characteristics and mechanisms. (1/5295)

Membrane potential was changed uniformly in segments, 0.7-1.0 mm long, of guinea pig papillary muscles excised from the right ventricle by using extracellular polarizing current pulses applied across two electrically insulated cf preparations superfused with Tyrode's solution at maximum diastolic membrane potentials ranging from-35.2+/-7.5 (threshold) to +4.0+/-9.2 mV. The average maximum dV/dt of RAD ranged from 17.1 to 18.0 V/sec within a membrane potential range of -40 to +20 mV. Raising extracellular Ca2+ concentration [Ca2+]0 from 1.8 to 6.8 mM, or application of isoproterenol (10(-6)g/ml) enhanced the rate of RAD, but lowering [Ca2+]0 to 0.4 mM or exposure to MnCl2 (6 mM) abolished RAD. RAD were enhanced by lowering extracellular K+ concentration [K+]0 from 5.4 to 1.5 mM. RAD were suppressed in 40% of fibers by raising [K+]0 to 15.4 mM, and in all fibers by raising [K+]0 to 40.4 mM. This suppression was due to increased [K+]0 and not to K-induced depolarization because it persisted when membrane potential was held by means of a conditioning hyperpolarizing puled gradually after maximum repolarization. These observations suggest that the development of RAD in depolarized myocardium is associated with a time-dependent decrease in outward current (probably K current) and with increase in the background inward current, presumably flowing through the slow cha-nel carrying Ca or Na ions, or both.  (+info)

Evaluation of the force-frequency relationship as a descriptor of the inotropic state of canine left ventricular myocardium. (2/5295)

The short-term force-frequency characteristics of canine left ventricular myocardium were examined in both isolated and intact preparations by briefly pertubing the frequency of contraction with early extrasystoles. The maximum rate of rise of isometric tension (Fmas) of the isolated trabeculae carneae was potentiated by the introduction of extrasystoles. The ratio of Fmas of potentiated to control beats (force-frequency ratio) was not altered significantly by a change in muscle length. However, exposure of the trabeculae to isoproterenol (10(-7)M) significantly changed the force-frequency ratio obtained in response to a constant frequency perturbation. Similar experiments were performed on chronically instrumented conscious dogs. Left ventricular minor axis diameter was measured with implanted pulse-transit ultrasonic dimension transducers, and intracavitary pressure was measured with a high fidelity micromanometer. Atrial pacing was performed so that the end-diastolic diameters of the beats preceding and following the extrasystole could be made identical. Large increases in the maximum rate of rise of pressure (Pmas) were seen in the contraction after the extrasystole. The ratio of Pmax of the potentiated beat to that of the control beat was not changed by a 9% increase in the end-diastolic diameter, produced by saline infusion. Conversely, isoproterenol significantly altered this relationship in the same manner as in the isolated muscle. Thus, either in vitro or in situ, left ventricular myocardium exhibits large functional changes in response to brief perturbations in rate. The isoproterenol and length data indicate that the force-frequency ratio reflects frequency-dependent changes in the inotropic state, independent of changes in length.  (+info)

AV reentrant and idiopathic ventricular double tachycardias: complicated interactions between two tachycardias. (3/5295)

An electrophysiological study was performed in a 61 year old man with Wolff- Parkinson-White (WPW) syndrome. At baseline, neither ventricular nor supraventricular tachycardias could be induced. During isoprenaline infusion, ventricular tachycardia originating from the right ventricular outflow tract (RVOT) with a cycle length of 280 ms was induced and subsequently atrioventricular reentrant tachycardia (AVRT) with a cycle length of 300 ms using an accessory pathway in the left free wall appeared. During these tachycardias, AVRT was entrained by ventricular tachycardia. The earliest ventricular activation site during the ventricular tachycardia was determined to be the RVOT site and a radiofrequency current at 30 W successfully ablated the ventricular tachycardia at this site. The left free wall accessory pathway was also successfully ablated during right ventricular pacing. The coexistence of WPW syndrome and cathecolamine sensitive ventricular tachycardia originating from the RVOT has rarely been reported. Furthermore, the tachycardias were triggered by previous tachycardias.  (+info)

Comparison of functional antagonism between isoproterenol and M2 muscarinic receptors in guinea pig ileum and trachea. (4/5295)

The ability of the M2 muscarinic receptor to mediate an inhibition of the relaxant effects of forskolin and isoproterenol was investigated in guinea pig ileum and trachea. In some experiments, trachea was first treated with 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) mustard to inactivate M3 receptors. The contractile response to oxotremorine-M was measured subsequently in the presence of both histamine (10 microM) and isoproterenol (10 nM). Under these conditions, [[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5, 11-dihydro-6H-pyrido[2,3b]-[1,4]benzodiazepine-6-one (AF-DX 116) antagonized the contractile response to oxotremorine-M in a manner consistent with an M3 mechanism. However, when the same experiment was repeated using forskolin (4 microM) instead of isoproterenol, the response to oxotremorine-M exhibited greater potency and was antagonized by AF-DX 116 in a manner consistent with an M2 mechanism. We also measured the effects of pertussis toxin treatment on the ability of isoproterenol to inhibit the contraction elicited by a single concentration of either histamine (0.3 microM) or oxotremorine-M (40 nM) in both the ileum and trachea. Pertussis toxin treatment had no significant effect on the potency of isoproterenol for inhibiting histamine-induced contractions in the ileum and trachea. In contrast, pertussis toxin treatment enhanced the relaxant potency of isoproterenol against oxotremorine-M-induced contractions in the ileum but not in the trachea. Also, pertussis toxin treatment enhanced the relaxant potency of forskolin against oxotremorine-M-induced contractions in the ileum and trachea. We investigated the relaxant potency of isoproterenol when very low, equi-effective (i.e., 20-34% of maximal response) concentrations of either histamine or oxotremorine-M were used to elicit contraction. Under these conditions, isoproterenol exhibited greater relaxant potency against histamine in the ileum but exhibited similar relaxant potencies against histamine and oxotremorine-M in the trachea. Following 4-DAMP mustard treatment, a low concentration of oxotremorine-M (10 nM) had no contractile effect in either the ileum or trachea. Nevertheless, in 4-DAMP mustard-treated tissue, oxotremorine-M (10 nM) reduced the relaxant potency of isoproterenol against histamine-induced contractions in the ileum, but not in the trachea. We conclude that in the trachea the M2 receptor mediates an inhibition of the relaxant effects of forskolin, but not isoproterenol, and the decreased relaxant potency of isoproterenol against contractions elicited by a muscarinic agonist relative to histamine is not due to activation of M2 receptors but rather to the greater contractile stimulus mediated by the M3 receptor compared with the H1 histamine receptor.  (+info)

Kinetic analysis of drug-receptor interactions of long-acting beta2 sympathomimetics in isolated receptor membranes: evidence against prolonged effects of salmeterol and formoterol on receptor-coupled adenylyl cyclase. (5/5295)

The long-acting beta2 sympathomimetics salmeterol and formoterol have been presumed to exert their prolonged action either by binding to an accessory binding site ("exo-site") near the beta2 adrenoceptor or by their high affinity for beta2 adrenoceptors and correspondingly slow dissociation. Whereas most studies with salmeterol had been done in intact tissues, which have slow diffusion and compartmentation of drugs in lipophilic phases, that restrict drug access to the receptor biophase, we used purified receptor membranes from rat lung and disaggregated calf tracheal myocytes as model systems. Binding experiments were designed to measure the slow dissociation of agonists by means of delayed association of (-)-[125I]iodopindolol. Rat lung membranes were pretreated with high concentrations of agonists (salmeterol, formoterol, isoprenaline) before dissociation was induced by 50-fold dilution. Half-times of association of (-)-[125I]iodopindolol remained unchanged compared with untreated controls, indicating that dissociation of agonists occurred in less than 2 min. Adenylyl cyclase experiments were designed to determine the on and off kinetics of agonists to beta2 adrenoceptors by measuring the rate of receptor-induced cyclic AMP (cAMP) formation. Experiments were performed in tracheal membranes characterized by high Vmax values of cAMP formation. Adenylyl cyclase activation occurred simultaneously with the addition of the agonist, continued linearly with time for 60 min, and ceased immediately after the antagonist was added. Similarly, when receptor membranes were preincubated in a small volume with high salmeterol concentrations, there was a linear increase in cAMP formation, which was immediately interrupted by a 100-fold dilution of the reaction mixture. This militates against the exo-site hypothesis. On the other hand, dissociation by dilution was much less when membranes were preincubated with a large volume of salmeterol at the same concentration, indicating that physicochemical effects, and not exo-site binding, underlie its prolonged mode of action.  (+info)

Angiotensin receptor subtype 1 mediates angiotensin II enhancement of isoproterenol-induced cyclic AMP production in preglomerular microvascular smooth muscle cells. (6/5295)

In a previous study, we found that angiotensin (Ang) II enhances beta-adrenoceptor-induced cAMP production in cultured preglomerular microvascular smooth muscle cells (PMVSMCs) obtained from spontaneously hypertensive rats. The purpose of the present investigation was to identify the Ang receptor subtypes that mediate this effect. In our first study, we compared the ability of Ang II, Ang III, Ang (3-8), and Ang (1-7) to increase cAMP production in isoproterenol (1 microM)-treated PMVSMCs. Each peptide was tested at 0.1, 1, 10, 100, and 1000 nM. Both Ang II and Ang III increased intracellular (EC50s, 1 and 11 nM, respectively) and extracellular (EC50s, 2 and 14 nM, respectively) cAMP levels in a concentration-dependent fashion. In contrast, Ang (3-8) and Ang (1-7) did not enhance either intracellular or extracellular cAMP levels at any concentration tested. In our second study, we examined the ability of L 158809 [a selective Ang receptor subtype 1 (AT1) receptor antagonist] to inhibit Ang II (100 nM) and Ang III (100 nM) enhancement of isoproterenol (1 microM)-induced cAMP production in PMVSMCs. L 158809 (10 nM) abolished or nearly abolished (p <.001) Ang II and Ang III enhancement of isoproterenol-induced intracellular and extracellular cAMP levels. In contrast, PD 123319 (300 nM; a selective AT2 receptor antagonist) did not significantly alter Ang II enhancement of isoproterenol-induced intracellular or extracellular cAMP levels. We conclude that AT1 receptors, but not AT2, Ang (3-8), nor Ang (1-7) receptors mediate Ang II and Ang III enhancement of beta-adrenoceptor-induced cAMP production in cultured PMVSMCs.  (+info)

Evidence for beta3-adrenoceptor subtypes in relaxation of the human urinary bladder detrusor: analysis by molecular biological and pharmacological methods. (7/5295)

The purpose of the present study was to confirm the presence of beta3-adrenoceptor subtype in the relaxation of human urinary bladder detrusor tissue by reverse transcription-polymerase chain reaction (PCR); direct sequencing of the PCR product, in situ hybridization; and isometric contraction. Using reverse transcription-PCR, the mRNAs of three receptor subtypes (beta1, beta2, and beta3) were expressed in the human urinary bladder detrusor tissue. Direct sequencing of the PCR product of the above beta3-adrenoceptor revealed no mutation in the amplified regions. In situ hybridization with digoxygenin-labeled oligonucleotide probe revealed the presence of the mRNA of beta3-adrenoceptor subtype in the smooth muscle of the urinary bladder. The relaxant effects of isoproterenol (a nonselective beta-adrenoceptor agonist); ZD7114, BRL37344, and CGP12177A (putative selective beta3-adrenoceptor agonists); and SR59230A (a putative selective beta3-adrenoceptor antagonist) were tested using an isometric contraction technique. Isoproterenol in either the presence or absence of both atenolol (a beta1-adrenoceptor-selective antagonist) and butoxamine (a beta2-adrenoceptor-selective antagonist) revealed a relaxant effect on the carbachol-induced contraction of the human urinary bladder detrusor. Both BRL37344 and CGP12177A also revealed relaxant effects on the human urinary bladder detrusor, but ZD7114 did not elicit any relaxation. These results suggest that beta3-adrenoceptor may have some role in urine storage in the human urinary bladder.  (+info)

A possible mode of cardiovascular actions of dopamine in dogs. (8/5295)

A possible mode of cardiovascular actions of dopamine was studied using ephedrine. In the dog pretreated with repeated administrations of ephedrine (total dose, 40 or 80 mg/kg, i.v.) or with combined administrations of ephedrine (total dose, 90 mg/kg, s.c. and i.v.) and reserpine (2 mg/kg, s.c., 24 hr previously), pressor responses to dopamine were eliminated and reversed to depressor responses whereas depressor responses to dopamine were potentiated. Positive chronotropic effects of dopamine were almost eliminated. Pressor and positive chronotropic effects of tyramine were almost abolished. Sympathomimetic effect of noradrenaline and adrenaline were potentiated while those of isoprenaline were inhibited. In the heart-lung preparation of ephedrine-treated dogs (total dose, 40 mg/kg, i.v.), cardiac stimulating effects of dopamine and tyramine were strongly depressed, and those of noradrenaline, adrenaline and isoprenaline were reduced to some extent. In the open-chest dogs, after pretreatment of cocaine (4 mg/kg, i.v.), pressor, positive inotropic and chronotropic effects of noradrenaline were potentiated, whilst those of tyramine were inhibited. Those of dopamine were not visibly altered, but depressor, negative chronotropic and inotropic effects of dopamine appeared at small doses. In the ephedrine-pretreated dogs, these sympathomimetic effects of dopamine and tyramine after cocaine were strongly depressed and those of noradrenaline were inhibited to a certain degree. The results obtained with ephedrine suggest that dopamine differs from other catecholamines and tyramine in the mode of cardiovascular actions.  (+info)

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.

Adrenergic beta-agonists are a class of medications that bind to and activate beta-adrenergic receptors, which are found in various tissues throughout the body. These receptors are part of the sympathetic nervous system and mediate the effects of the neurotransmitter norepinephrine (also called noradrenaline) and the hormone epinephrine (also called adrenaline).

When beta-agonists bind to these receptors, they stimulate a range of physiological responses, including relaxation of smooth muscle in the airways, increased heart rate and contractility, and increased metabolic rate. As a result, adrenergic beta-agonists are often used to treat conditions such as asthma, chronic obstructive pulmonary disease (COPD), and bronchitis, as they can help to dilate the airways and improve breathing.

There are several different types of beta-agonists, including short-acting and long-acting formulations. Short-acting beta-agonists (SABAs) are typically used for quick relief of symptoms, while long-acting beta-agonists (LABAs) are used for more sustained symptom control. Examples of adrenergic beta-agonists include albuterol (also known as salbutamol), terbutaline, formoterol, and salmeterol.

It's worth noting that while adrenergic beta-agonists can be very effective in treating respiratory conditions, they can also have side effects, particularly if used in high doses or for prolonged periods of time. These may include tremors, anxiety, palpitations, and increased blood pressure. As with any medication, it's important to use adrenergic beta-agonists only as directed by a healthcare professional.

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).

Propranolol is a medication that belongs to a class of drugs called beta blockers. Medically, it is defined as a non-selective beta blocker, which means it blocks the effects of both epinephrine (adrenaline) and norepinephrine (noradrenaline) on the heart and other organs. These effects include reducing heart rate, contractility, and conduction velocity, leading to decreased oxygen demand by the myocardium. Propranolol is used in the management of various conditions such as hypertension, angina pectoris, arrhythmias, essential tremor, anxiety disorders, and infants with congenital heart defects. It may also be used to prevent migraines and reduce the risk of future heart attacks. As with any medication, it should be taken under the supervision of a healthcare provider due to potential side effects and contraindications.

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.

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.

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.

Adrenergic receptors are a type of G protein-coupled receptor that bind and respond to catecholamines, which include the neurotransmitters norepinephrine (noradrenaline) and epinephrine (adrenaline). These receptors play a crucial role in the body's "fight or flight" response and are involved in regulating various physiological functions such as heart rate, blood pressure, respiration, and metabolism.

There are nine different subtypes of adrenergic receptors, which are classified into two main groups based on their pharmacological properties: alpha (α) and beta (β) receptors. Alpha receptors are further divided into two subgroups, α1 and α2, while beta receptors are divided into three subgroups, β1, β2, and β3. Each subtype has a unique distribution in the body and mediates distinct physiological responses.

Activation of adrenergic receptors occurs when catecholamines bind to their specific binding sites on the receptor protein. This binding triggers a cascade of intracellular signaling events that ultimately lead to changes in cell function. Different subtypes of adrenergic receptors activate different G proteins and downstream signaling pathways, resulting in diverse physiological responses.

In summary, adrenergic receptors are a class of G protein-coupled receptors that bind catecholamines and mediate various physiological functions. Understanding the function and regulation of these receptors is essential for developing therapeutic strategies to treat a range of medical conditions, including hypertension, heart failure, asthma, and anxiety disorders.

Sympathomimetic drugs are substances that mimic or stimulate the actions of the sympathetic nervous system. The sympathetic nervous system is one of the two divisions of the autonomic nervous system, which regulates various automatic physiological functions in the body. The sympathetic nervous system's primary function is to prepare the body for the "fight-or-flight" response, which includes increasing heart rate, blood pressure, respiratory rate, and metabolism while decreasing digestive activity.

Sympathomimetic drugs can exert their effects through various mechanisms, including directly stimulating adrenergic receptors (alpha and beta receptors) or indirectly causing the release of norepinephrine and epinephrine from nerve endings. These drugs are used in various clinical settings to treat conditions such as asthma, nasal congestion, low blood pressure, and attention deficit hyperactivity disorder (ADHD). Examples of sympathomimetic drugs include epinephrine, norepinephrine, dopamine, dobutamine, albuterol, pseudoephedrine, and methylphenidate.

It is important to note that sympathomimetic drugs can also have adverse effects, particularly when used in high doses or in individuals with certain medical conditions. These adverse effects may include anxiety, tremors, palpitations, hypertension, arrhythmias, and seizures. Therefore, these medications should be used under the close supervision of a healthcare provider.

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.

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.

Adrenergic receptors are a type of G protein-coupled receptor that bind and respond to catecholamines, such as epinephrine (adrenaline) and norepinephrine (noradrenaline). Beta-2 adrenergic receptors (β2-ARs) are a subtype of adrenergic receptors that are widely distributed throughout the body, particularly in the lungs, heart, blood vessels, gastrointestinal tract, and skeletal muscle.

When β2-ARs are activated by catecholamines, they trigger a range of physiological responses, including relaxation of smooth muscle, increased heart rate and contractility, bronchodilation, and inhibition of insulin secretion. These effects are mediated through the activation of intracellular signaling pathways involving G proteins and second messengers such as cyclic AMP (cAMP).

β2-ARs have been a major focus of drug development for various medical conditions, including asthma, chronic obstructive pulmonary disease (COPD), heart failure, hypertension, and anxiety disorders. Agonists of β2-ARs, such as albuterol and salmeterol, are commonly used to treat asthma and COPD by relaxing bronchial smooth muscle and reducing airway obstruction. Antagonists of β2-ARs, such as propranolol, are used to treat hypertension, angina, and heart failure by blocking the effects of catecholamines on the heart and blood vessels.

The parotid gland is the largest of the major salivary glands. It is a bilobed, accessory digestive organ that secretes serous saliva into the mouth via the parotid duct (Stensen's duct), located near the upper second molar tooth. The parotid gland is primarily responsible for moistening and lubricating food to aid in swallowing and digestion.

Anatomically, the parotid gland is located in the preauricular region, extending from the zygomatic arch superiorly to the angle of the mandible inferiorly, and from the masseter muscle anteriorly to the sternocleidomastoid muscle posteriorly. It is enclosed within a fascial capsule and has a rich blood supply from the external carotid artery and a complex innervation pattern involving both parasympathetic and sympathetic fibers.

Parotid gland disorders can include salivary gland stones (sialolithiasis), infections, inflammatory conditions, benign or malignant tumors, and autoimmune diseases such as Sjögren's syndrome.

Adrenergic beta-antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-adrenergic receptors. These receptors are found in various tissues throughout the body, including the heart, lungs, and blood vessels.

Beta blockers work by binding to these receptors and preventing the activation of certain signaling pathways that lead to increased heart rate, force of heart contractions, and relaxation of blood vessels. As a result, beta blockers can lower blood pressure, reduce heart rate, and decrease the workload on the heart.

Beta blockers are used to treat a variety of medical conditions, including hypertension (high blood pressure), angina (chest pain), heart failure, irregular heart rhythms, migraines, and certain anxiety disorders. Some common examples of beta blockers include metoprolol, atenolol, propranolol, and bisoprolol.

It is important to note that while beta blockers can have many benefits, they can also cause side effects such as fatigue, dizziness, and shortness of breath. Additionally, sudden discontinuation of beta blocker therapy can lead to rebound hypertension or worsening chest pain. Therefore, it is important to follow the dosing instructions provided by a healthcare provider carefully when taking these medications.

Dihydroalprenolol is a non-selective beta blocker drug, which means it blocks both beta-1 and beta-2 receptors. Beta blockers are medications that reduce the effects of epinephrine (adrenaline) in the body, thereby slowing down the heart rate, reducing blood pressure, and decreasing the force of heart contractions.

Dihydroalprenolol is primarily used to treat hypertension (high blood pressure), angina pectoris (chest pain due to reduced blood flow to the heart muscle), and certain types of arrhythmias (irregular heart rhythms). It may also be used for other indications, such as preventing migraines or reducing anxiety before surgery.

Like other beta blockers, dihydroalprenolol works by blocking the action of epinephrine on beta receptors in the heart and blood vessels, leading to decreased heart rate, reduced force of heart contractions, and dilated blood vessels. This results in lower blood pressure and improved blood flow to the heart muscle.

It is important to note that dihydroalprenolol may have side effects, such as fatigue, dizziness, and gastrointestinal symptoms, and it should be used under the guidance of a healthcare professional. Additionally, sudden discontinuation of beta blockers can lead to rebound hypertension or other adverse effects, so it is essential to taper off the medication gradually under medical supervision.

Beta-1 adrenergic receptors (also known as β1-adrenergic receptors) are a type of G protein-coupled receptor found in the cell membrane. They are activated by the catecholamines, particularly noradrenaline (norepinephrine) and adrenaline (epinephrine), which are released by the sympathetic nervous system as part of the "fight or flight" response.

When a catecholamine binds to a β1-adrenergic receptor, it triggers a series of intracellular signaling events that ultimately lead to an increase in the rate and force of heart contractions, as well as an increase in renin secretion from the kidneys. These effects help to prepare the body for physical activity by increasing blood flow to the muscles and improving the efficiency of the cardiovascular system.

In addition to their role in the regulation of cardiovascular function, β1-adrenergic receptors have been implicated in a variety of physiological processes, including lipolysis (the breakdown of fat), glucose metabolism, and the regulation of mood and cognition.

Dysregulation of β1-adrenergic receptor signaling has been linked to several pathological conditions, including heart failure, hypertension, and anxiety disorders. As a result, β1-adrenergic receptors are an important target for the development of therapeutics used in the treatment of these conditions.

Cardiotonic agents are a type of medication that have a positive inotropic effect on the heart, meaning they help to improve the contractility and strength of heart muscle contractions. These medications are often used to treat heart failure, as they can help to improve the efficiency of the heart's pumping ability and increase cardiac output.

Cardiotonic agents work by increasing the levels of calcium ions inside heart muscle cells during each heartbeat, which in turn enhances the force of contraction. Some common examples of cardiotonic agents include digitalis glycosides (such as digoxin), which are derived from the foxglove plant, and synthetic medications such as dobutamine and milrinone.

While cardiotonic agents can be effective in improving heart function, they can also have potentially serious side effects, including arrhythmias, electrolyte imbalances, and digestive symptoms. As a result, they are typically used under close medical supervision and their dosages may need to be carefully monitored to minimize the risk of adverse effects.

Pindolol is a non-selective beta blocker that is used in the treatment of hypertension (high blood pressure) and certain types of arrhythmias (irregular heart rhythms). It works by blocking the action of certain hormones such as adrenaline and noradrenaline on the heart, which helps to reduce the heart rate, contractility, and conduction velocity, leading to a decrease in blood pressure.

Pindolol is also a partial agonist at beta-2 receptors, which means that it can stimulate these receptors to some extent, reducing the likelihood of bronchospasm (a side effect seen with other non-selective beta blockers). However, pindolol may still cause bronchospasm in patients with a history of asthma or chronic obstructive pulmonary disease (COPD), so it should be used with caution in these populations.

Pindolol is available in immediate-release and extended-release formulations, and the dosage is typically individualized based on the patient's response to therapy. Common side effects of pindolol include dizziness, fatigue, and gastrointestinal symptoms such as nausea and diarrhea.

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.

Iodocyanopindolol is not a medical term itself, but it is a specific type of compound with potential use in medical research and testing. It's a non-selective beta-blocker that contains iodine-125, a radioactive isotope, making it useful for radiolabeling and tracking its distribution within the body.

Iodocyanopindolol can be used as a radioligand in positron emission tomography (PET) scans to study beta-adrenergic receptors in the heart and brain. This information is helpful for researchers investigating conditions related to these systems, such as cardiovascular diseases or neuropsychiatric disorders.

In summary, Iodocyanopindolol is a radiolabeled non-selective beta-blocker used primarily for research purposes in medical imaging and understanding the function of beta-adrenergic receptors in the body.

Epinephrine, also known as adrenaline, is a hormone and a neurotransmitter that is produced in the body. It is released by the adrenal glands in response to stress or excitement, and it prepares the body for the "fight or flight" response. Epinephrine works by binding to specific receptors in the body, which causes a variety of physiological effects, including increased heart rate and blood pressure, improved muscle strength and alertness, and narrowing of the blood vessels in the skin and intestines. It is also used as a medication to treat various medical conditions, such as anaphylaxis (a severe allergic reaction), cardiac arrest, and low blood pressure.

Adrenergic agonists are medications or substances that bind to and activate adrenergic receptors, which are a type of receptor in the body that respond to neurotransmitters such as norepinephrine and epinephrine (also known as adrenaline).

There are two main types of adrenergic receptors: alpha and beta receptors. Alpha-adrenergic agonists activate alpha receptors, while beta-adrenergic agonists activate beta receptors. These medications can have a variety of effects on the body, depending on which type of receptor they act on.

Alpha-adrenergic agonists are often used to treat conditions such as nasal congestion, glaucoma, and low blood pressure. Examples include phenylephrine, oxymetazoline, and clonidine.

Beta-adrenergic agonists are commonly used to treat respiratory conditions such as asthma and COPD (chronic obstructive pulmonary disease). They work by relaxing the smooth muscle in the airways, which makes it easier to breathe. Examples include albuterol, salmeterol, and formoterol.

It's important to note that adrenergic agonists can have both desired and undesired effects on the body. They should be used under the guidance of a healthcare professional, who can monitor their effectiveness and potential side effects.

Propanolamines are a class of pharmaceutical compounds that contain a propan-2-olamine functional group, which is a secondary amine formed by the replacement of one hydrogen atom in an ammonia molecule with a propan-2-ol group. They are commonly used as decongestants and bronchodilators in medical treatments.

Examples of propanolamines include:

* Phenylephrine: a decongestant used to relieve nasal congestion.
* Pseudoephedrine: a decongestant and stimulant used to treat nasal congestion and sinus pressure.
* Ephedrine: a bronchodilator, decongestant, and stimulant used to treat asthma, nasal congestion, and low blood pressure.

It is important to note that propanolamines can have side effects such as increased heart rate, elevated blood pressure, and insomnia, so they should be used with caution and under the supervision of a healthcare professional.

Norepinephrine, also known as noradrenaline, is a neurotransmitter and a hormone that is primarily produced in the adrenal glands and is released into the bloodstream in response to stress or physical activity. It plays a crucial role in the "fight-or-flight" response by preparing the body for action through increasing heart rate, blood pressure, respiratory rate, and glucose availability.

As a neurotransmitter, norepinephrine is involved in regulating various functions of the nervous system, including attention, perception, motivation, and arousal. It also plays a role in modulating pain perception and responding to stressful or emotional situations.

In medical settings, norepinephrine is used as a vasopressor medication to treat hypotension (low blood pressure) that can occur during septic shock, anesthesia, or other critical illnesses. It works by constricting blood vessels and increasing heart rate, which helps to improve blood pressure and perfusion of vital organs.

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.

Alprenolol is a beta-blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and various heart rhythm disorders. It works by blocking the action of certain hormones in the body, such as adrenaline, that can cause the heart to beat faster or with increased force. This helps to reduce the workload on the heart and lower blood pressure.

Alprenolol may also be used for other purposes, such as preventing migraines or treating anxiety disorders. It is available in immediate-release and extended-release tablets, and is typically taken two to three times a day. As with any medication, Alprenolol can have side effects, including dizziness, fatigue, and gastrointestinal symptoms such as nausea or diarrhea. It is important to follow the dosage instructions provided by your healthcare provider and to report any bothersome or persistent side effects.

Phenylephrine is a medication that belongs to the class of drugs known as sympathomimetic amines. It primarily acts as an alpha-1 adrenergic receptor agonist, which means it stimulates these receptors, leading to vasoconstriction (constriction of blood vessels). This effect can be useful in various medical situations, such as:

1. Nasal decongestion: When applied topically in the nose, phenylephrine causes constriction of the blood vessels in the nasal passages, which helps to relieve congestion and swelling. It is often found in over-the-counter (OTC) cold and allergy products.
2. Ocular circulation: In ophthalmology, phenylephrine is used to dilate the pupils before eye examinations. The increased pressure from vasoconstriction helps to open up the pupil, allowing for a better view of the internal structures of the eye.
3. Hypotension management: In some cases, phenylephrine may be given intravenously to treat low blood pressure (hypotension) during medical procedures like spinal anesthesia or septic shock. The vasoconstriction helps to increase blood pressure and improve perfusion of vital organs.

It is essential to use phenylephrine as directed, as improper usage can lead to adverse effects such as increased heart rate, hypertension, arrhythmias, and rebound congestion (when used as a nasal decongestant). Always consult with a healthcare professional for appropriate guidance on using this medication.

Catecholamines are a group of hormones and neurotransmitters that are derived from the amino acid tyrosine. The most well-known catecholamines are dopamine, norepinephrine (also known as noradrenaline), and epinephrine (also known as adrenaline). These hormones are produced by the adrenal glands and are released into the bloodstream in response to stress. They play important roles in the "fight or flight" response, increasing heart rate, blood pressure, and alertness. In addition to their role as hormones, catecholamines also function as neurotransmitters, transmitting signals in the nervous system. Disorders of catecholamine regulation can lead to a variety of medical conditions, including hypertension, mood disorders, and neurological disorders.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

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.

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.

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.

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.

Adrenergic alpha-agonists are a type of medication that binds to and activates adrenergic alpha receptors, which are found in the nervous system and other tissues throughout the body. These receptors are activated naturally by chemicals called catecholamines, such as norepinephrine and epinephrine (also known as adrenaline), that are released in response to stress or excitement.

When adrenergic alpha-agonists bind to these receptors, they mimic the effects of catecholamines and cause various physiological responses, such as vasoconstriction (constriction of blood vessels), increased heart rate and force of heart contractions, and relaxation of smooth muscle in the airways.

Adrenergic alpha-agonists are used to treat a variety of medical conditions, including hypertension (high blood pressure), glaucoma, nasal congestion, and attention deficit hyperactivity disorder (ADHD). Examples of adrenergic alpha-agonists include phenylephrine, clonidine, and guanfacine.

It's important to note that adrenergic alpha-agonists can have both beneficial and harmful effects, depending on the specific medication, dosage, and individual patient factors. Therefore, they should only be used under the guidance of a healthcare professional.

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.

GTP-binding protein alpha subunits, Gs, are a type of heterotrimeric G proteins that play a crucial role in the transmission of signals within cells. These proteins are composed of three subunits: alpha, beta, and gamma. The alpha subunit of Gs proteins (Gs-alpha) is responsible for activating adenylyl cyclase, an enzyme that converts ATP to cyclic AMP (cAMP), a secondary messenger involved in various cellular processes.

When a G protein-coupled receptor (GPCR) is activated by an extracellular signal, it interacts with and activates the Gs protein. This activation causes the exchange of guanosine diphosphate (GDP) bound to the alpha subunit with guanosine triphosphate (GTP). The GTP-bound Gs-alpha then dissociates from the beta-gamma subunits and interacts with adenylyl cyclase, activating it and leading to an increase in cAMP levels. This signaling cascade ultimately results in various cellular responses, such as changes in gene expression, metabolism, or cell growth and differentiation.

It is important to note that mutations in the GNAS gene, which encodes the Gs-alpha subunit, can lead to several endocrine and non-endocrine disorders, such as McCune-Albright syndrome, fibrous dysplasia, and various hormone-related diseases.

Heart rate is the number of heartbeats per unit of time, often expressed as beats per minute (bpm). It can vary significantly depending on factors such as age, physical fitness, emotions, and overall health status. A resting heart rate between 60-100 bpm is generally considered normal for adults, but athletes and individuals with high levels of physical fitness may have a resting heart rate below 60 bpm due to their enhanced cardiovascular efficiency. Monitoring heart rate can provide valuable insights into an individual's health status, exercise intensity, and response to various treatments or interventions.

Adrenergic beta-1 receptor agonists are a type of medication that binds to and activates the beta-1 adrenergic receptors, which are found primarily in the heart. When these receptors are activated, they cause an increase in heart rate, contractility, and conduction velocity, leading to an increased cardiac output.

These medications are used to treat various conditions such as heart failure, bradycardia (a slow heart rate), and cardiogenic shock. Examples of adrenergic beta-1 receptor agonists include dobutamine, dopamine, and isoproterenol. It's important to note that these medications can also have effects on other adrenergic receptors, so it's crucial to monitor for potential side effects such as hypertension, arrhythmias, and bronchodilation.

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.

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.

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.

Phentolamine is a non-selective alpha-blocker drug, which means it blocks both alpha-1 and alpha-2 receptors. It works by relaxing the muscle around blood vessels, which increases blood flow and lowers blood pressure. Phentolamine is used medically for various purposes, including the treatment of high blood pressure, the diagnosis and treatment of pheochromocytoma (a tumor that releases hormones causing high blood pressure), and as an antidote to prevent severe hypertension caused by certain medications or substances. It may also be used in diagnostic tests to determine if a patient's blood pressure is reactive to drugs, and it can be used during some surgical procedures to help lower the risk of hypertensive crises.

Phentolamine is available in two forms: an injectable solution and oral tablets. The injectable form is typically administered by healthcare professionals in a clinical setting, while the oral tablets are less commonly used due to their short duration of action and potential for causing severe drops in blood pressure. As with any medication, phentolamine should be taken under the supervision of a healthcare provider, and patients should follow their doctor's instructions carefully to minimize the risk of side effects and ensure the drug's effectiveness.

Cardiomegaly is a medical term that refers to an enlarged heart. It can be caused by various conditions such as high blood pressure, heart valve problems, cardiomyopathy, or fluid accumulation around the heart (pericardial effusion). Cardiomegaly can be detected through imaging tests like chest X-rays or echocardiograms. Depending on the underlying cause, treatment options may include medications, lifestyle changes, or in some cases, surgery. It is important to consult with a healthcare professional for proper diagnosis and treatment.

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.

Lipolysis is the process by which fat cells (adipocytes) break down stored triglycerides into glycerol and free fatty acids. This process occurs when the body needs to use stored fat as a source of energy, such as during fasting, exercise, or in response to certain hormonal signals. The breakdown products of lipolysis can be used directly by cells for energy production or can be released into the bloodstream and transported to other tissues for use. Lipolysis is regulated by several hormones, including adrenaline (epinephrine), noradrenaline (norepinephrine), cortisol, glucagon, and growth hormone, which act on lipases, enzymes that mediate the breakdown of triglycerides.

"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.

"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.

Beta-3 adrenergic receptors (β3-AR) are a type of G protein-coupled receptor that binds catecholamines, such as norepinephrine and epinephrine. These receptors are primarily located in the adipose tissue, where they play a role in regulating lipolysis (the breakdown of fat) and thermogenesis (the production of heat).

Activation of β3-AR stimulates the enzyme hormone-sensitive lipase, which leads to the hydrolysis of triglycerides and the release of free fatty acids. This process is important for maintaining energy homeostasis and can be activated through exercise, cold exposure, or pharmacological means.

In addition to their role in metabolism, β3-AR have also been implicated in the regulation of cardiovascular function, bladder function, and inflammation. Selective β3-AR agonists are being investigated as potential therapeutic agents for the treatment of obesity, type 2 diabetes, and nonalcoholic fatty liver disease.

Diphenylacetic acids are a group of organic compounds characterized by the structure R-C6H4-COOH, where R represents a phenyl group (C6H5). These compounds contain two aromatic rings and an acidic functional group, making them diphenyl carboxylic acids. They can have various biological activities and are used in pharmaceuticals, agrochemicals, and other industrial applications. Some examples of diphenylacetic acids include:

1. Diphenylacetic acid (DPA): The simplest form of the compound with no substituents on either phenyl ring.
2. 2'-Hydroxy-diphenylacetic acid (HDPA): A derivative of diphenylacetic acid, containing a hydroxyl group (-OH) on one of the phenyl rings.
3. Diphenylacetic acid esters: Esters derived from diphenylacetic acids by reacting with alcohols, which can have various biological activities and are used in pharmaceuticals and agrochemicals.

It is important to note that specific medical definitions for 'diphenylacetic acids' may vary depending on the context and application.

Adrenergic receptors are a type of G protein-coupled receptor that bind and respond to catecholamines, such as epinephrine (adrenaline) and norepinephrine (noradrenaline). Alpha adrenergic receptors (α-ARs) are a subtype of adrenergic receptors that are classified into two main categories: α1-ARs and α2-ARs.

The activation of α1-ARs leads to the activation of phospholipase C, which results in an increase in intracellular calcium levels and the activation of various signaling pathways that mediate diverse physiological responses such as vasoconstriction, smooth muscle contraction, and cell proliferation.

On the other hand, α2-ARs are primarily located on presynaptic nerve terminals where they function to inhibit the release of neurotransmitters, including norepinephrine. The activation of α2-ARs also leads to the inhibition of adenylyl cyclase and a decrease in intracellular cAMP levels, which can mediate various physiological responses such as sedation, analgesia, and hypotension.

Overall, α-ARs play important roles in regulating various physiological functions, including cardiovascular function, mood, and cognition, and are also involved in the pathophysiology of several diseases, such as hypertension, heart failure, and neurodegenerative disorders.

Papillary muscles are specialized muscle structures located in the heart, specifically in the ventricles (the lower chambers of the heart). They are attached to the tricuspid and mitral valves' leaflets via tendinous cords, also known as chordae tendineae. The main function of papillary muscles is to prevent the backflow of blood during contraction by providing tension to the valve leaflets through these tendinous cords.

There are two sets of papillary muscles in the heart:

1. Anterior and posterior papillary muscles in the left ventricle, which are attached to the mitral (bicuspid) valve.
2. Three smaller papillary muscles in the right ventricle, which are attached to the tricuspid valve.

These muscle structures play a crucial role in maintaining proper blood flow through the heart and ensuring efficient cardiac function.

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.

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.

"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.

Adenosine is a purine nucleoside that is composed of a sugar (ribose) and the base adenine. It plays several important roles in the body, including serving as a precursor for the synthesis of other molecules such as ATP, NAD+, and RNA.

In the medical context, adenosine is perhaps best known for its use as a pharmaceutical agent to treat certain cardiac arrhythmias. When administered intravenously, it can help restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT) by slowing conduction through the atrioventricular node and interrupting the reentry circuit responsible for the arrhythmia.

Adenosine can also be used as a diagnostic tool to help differentiate between narrow-complex tachycardias of supraventricular origin and those that originate from below the ventricles (such as ventricular tachycardia). This is because adenosine will typically terminate PSVT but not affect the rhythm of VT.

It's worth noting that adenosine has a very short half-life, lasting only a few seconds in the bloodstream. This means that its effects are rapidly reversible and generally well-tolerated, although some patients may experience transient symptoms such as flushing, chest pain, or shortness of breath.

The trachea, also known as the windpipe, is a tube-like structure in the respiratory system that connects the larynx (voice box) to the bronchi (the two branches leading to each lung). It is composed of several incomplete rings of cartilage and smooth muscle, which provide support and flexibility. The trachea plays a crucial role in directing incoming air to the lungs during inspiration and outgoing air to the larynx during expiration.

Proline-rich protein domains are segments within proteins that contain an unusually high concentration of the amino acid proline. These domains are often involved in mediating protein-protein interactions and can play a role in various cellular processes, such as signal transduction, gene regulation, and protein folding. They are also commonly found in extracellular matrix proteins and may be involved in cell adhesion and migration. The unique chemical properties of proline, including its ability to form rigid structures and disrupt alpha-helices, contribute to the functional specificity of these domains.

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.

Cholera toxin is a protein toxin produced by the bacterium Vibrio cholerae, which causes the infectious disease cholera. The toxin is composed of two subunits, A and B, and its primary mechanism of action is to alter the normal function of cells in the small intestine.

The B subunit of the toxin binds to ganglioside receptors on the surface of intestinal epithelial cells, allowing the A subunit to enter the cell. Once inside, the A subunit activates a signaling pathway that results in the excessive secretion of chloride ions and water into the intestinal lumen, leading to profuse, watery diarrhea, dehydration, and other symptoms associated with cholera.

Cholera toxin is also used as a research tool in molecular biology and immunology due to its ability to modulate cell signaling pathways. It has been used to study the mechanisms of signal transduction, protein trafficking, and immune responses.

Ventricular function, in the context of cardiac medicine, refers to the ability of the heart's ventricles (the lower chambers) to fill with blood during the diastole phase and eject blood during the systole phase. The ventricles are primarily responsible for pumping oxygenated blood out to the body (left ventricle) and deoxygenated blood to the lungs (right ventricle).

There are several ways to assess ventricular function, including:

1. Ejection Fraction (EF): This is the most commonly used measure of ventricular function. It represents the percentage of blood that is ejected from the ventricle during each heartbeat. A normal left ventricular ejection fraction is typically between 55% and 70%.
2. Fractional Shortening (FS): This is another measure of ventricular function, which calculates the change in size of the ventricle during contraction as a percentage of the original size. A normal FS for the left ventricle is typically between 25% and 45%.
3. Stroke Volume (SV): This refers to the amount of blood that is pumped out of the ventricle with each heartbeat. SV is calculated by multiplying the ejection fraction by the end-diastolic volume (the amount of blood in the ventricle at the end of diastole).
4. Cardiac Output (CO): This is the total amount of blood that the heart pumps in one minute. It is calculated by multiplying the stroke volume by the heart rate.

Impaired ventricular function can lead to various cardiovascular conditions, such as heart failure, cardiomyopathy, and valvular heart disease. Assessing ventricular function is crucial for diagnosing these conditions, monitoring treatment response, and guiding clinical decision-making.

Adrenergic beta-2 receptor agonists are a class of medications that bind to and stimulate beta-2 adrenergic receptors, which are found in various tissues throughout the body, including the lungs, blood vessels, and skeletal muscles. These receptors are part of the sympathetic nervous system and play a role in regulating various physiological processes such as heart rate, blood pressure, and airway diameter.

When beta-2 receptor agonists bind to these receptors, they cause bronchodilation (opening of the airways), relaxation of smooth muscle, and increased heart rate and force of contraction. These effects make them useful in the treatment of conditions such as asthma, chronic obstructive pulmonary disease (COPD), and premature labor.

Examples of adrenergic beta-2 receptor agonists include albuterol, terbutaline, salmeterol, and formoterol. These medications can be administered by inhalation, oral administration, or injection, depending on the specific drug and the condition being treated.

It's important to note that while adrenergic beta-2 receptor agonists are generally safe and effective when used as directed, they can have side effects such as tremors, anxiety, palpitations, and headaches. In addition, long-term use of some beta-2 agonists has been associated with increased risk of severe asthma exacerbations and even death in some cases. Therefore, it's important to use these medications only as directed by a healthcare provider and to report any concerning symptoms promptly.

The heart atria are the upper chambers of the heart that receive blood from the veins and deliver it to the lower chambers, or ventricles. There are two atria in the heart: the right atrium receives oxygen-poor blood from the body and pumps it into the right ventricle, which then sends it to the lungs to be oxygenated; and the left atrium receives oxygen-rich blood from the lungs and pumps it into the left ventricle, which then sends it out to the rest of the body. The atria contract before the ventricles during each heartbeat, helping to fill the ventricles with blood and prepare them for contraction.

Perfusion, in medical terms, refers to the process of circulating blood through the body's organs and tissues to deliver oxygen and nutrients and remove waste products. It is a measure of the delivery of adequate blood flow to specific areas or tissues in the body. Perfusion can be assessed using various methods, including imaging techniques like computed tomography (CT) scans, magnetic resonance imaging (MRI), and perfusion scintigraphy.

Perfusion is critical for maintaining proper organ function and overall health. When perfusion is impaired or inadequate, it can lead to tissue hypoxia, acidosis, and cell death, which can result in organ dysfunction or failure. Conditions that can affect perfusion include cardiovascular disease, shock, trauma, and certain surgical procedures.

Adrenergic beta-2 receptor antagonists, also known as beta-2 adrenergic blockers or beta-2 antagonists, are a class of medications that block the action of epinephrine (adrenaline) and other catecholamines at beta-2 adrenergic receptors. These receptors are found in various tissues throughout the body, including the lungs, blood vessels, and skeletal muscles.

Beta-2 adrenergic receptor antagonists are primarily used to treat respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). They work by relaxing the smooth muscle in the airways, which helps to reduce bronchoconstriction and improve breathing.

Some examples of beta-2 adrenergic receptor antagonists include:

* Butoxamine
* ICI 118,551
* Salbutamol (also a partial agonist)
* Terbutaline (also a partial agonist)

It's important to note that while these medications are called "antagonists," some of them can also act as partial agonists at beta-2 receptors, meaning they can both block the action of catecholamines and stimulate the receptor to some degree. This property can make them useful in certain clinical situations, such as during an asthma attack or preterm labor.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

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.

Sodium fluoride is an inorganic compound with the chemical formula NaF. Medically, it is commonly used as a dental treatment to prevent tooth decay, as it is absorbed into the structure of teeth and helps to harden the enamel, making it more resistant to acid attacks from bacteria. It can also reduce the ability of bacteria to produce acid. Sodium fluoride is often found in toothpastes, mouth rinses, and various dental treatments. However, excessive consumption can lead to dental fluorosis and skeletal fluorosis, which cause changes in bone structure and might negatively affect health.

Methoxamine is a synthetic, selective α1-adrenergic receptor agonist used in scientific research and for therapeutic purposes. It has the ability to stimulate the α1 adrenergic receptors, leading to vasoconstriction (constriction of blood vessels), increased blood pressure, and reduced blood flow to the skin and extremities.

In a medical context, methoxamine is primarily used as an experimental drug or in research settings due to its specific pharmacological properties. It may be employed to investigate the role of α1-adrenergic receptors in various physiological processes or to temporarily counteract the hypotensive (low blood pressure) effects of certain medications, such as vasodilators or anesthetics.

It is important to note that methoxamine is not commonly used in routine clinical practice due to its strong vasoconstrictive properties and potential adverse effects on organ function if misused or improperly dosed.

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.

GTP-binding proteins, also known as G proteins, are a family of molecular switches present in many organisms, including humans. They play a crucial role in signal transduction pathways, particularly those involved in cellular responses to external stimuli such as hormones, neurotransmitters, and sensory signals like light and odorants.

G proteins are composed of three subunits: α, β, and γ. The α-subunit binds GTP (guanosine triphosphate) and acts as the active component of the complex. When a G protein-coupled receptor (GPCR) is activated by an external signal, it triggers a conformational change in the associated G protein, allowing the α-subunit to exchange GDP (guanosine diphosphate) for GTP. This activation leads to dissociation of the G protein complex into the GTP-bound α-subunit and the βγ-subunit pair. Both the α-GTP and βγ subunits can then interact with downstream effectors, such as enzymes or ion channels, to propagate and amplify the signal within the cell.

The intrinsic GTPase activity of the α-subunit eventually hydrolyzes the bound GTP to GDP, which leads to re-association of the α and βγ subunits and termination of the signal. This cycle of activation and inactivation makes G proteins versatile signaling elements that can respond quickly and precisely to changing environmental conditions.

Defects in G protein-mediated signaling pathways have been implicated in various diseases, including cancer, neurological disorders, and cardiovascular diseases. Therefore, understanding the function and regulation of GTP-binding proteins is essential for developing targeted therapeutic strategies.

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.

Guanylyl Imidodiphosphate (GIP) is not a medical term itself, but it is a biochemical compound that plays a crucial role in the body's signaling pathways. It is a vital intracellular second messenger involved in various physiological processes, including vasodilation and smooth muscle relaxation.

To be more specific, GIP is a nucleotide that activates a family of enzymes called guanylyl cyclases (GCs). Once activated, these enzymes convert guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP), another essential second messenger. The increased levels of cGMP then mediate the relaxation of smooth muscle and vasodilation by activating protein kinases and ion channels, among other mechanisms.

In summary, Guanylyl Imidodiphosphate (GIP) is a biochemical compound that plays a critical role in intracellular signaling pathways, leading to vasodilation and smooth muscle relaxation.

Aminophylline is a medication that is used to treat and prevent respiratory symptoms such as bronchospasm, wheezing, and shortness of breath. It is a combination of theophylline and ethylenediamine, and it works by relaxing muscles in the airways and increasing the efficiency of the diaphragm, which makes breathing easier.

Aminophylline is classified as a xanthine derivative and a methylxanthine bronchodilator. It is available in various forms, including tablets, capsules, and liquid solutions, and it is typically taken by mouth two to three times a day. The medication may also be given intravenously in hospital settings for the treatment of acute respiratory distress.

Common side effects of aminophylline include nausea, vomiting, headache, and insomnia. More serious side effects can occur at higher doses and may include irregular heartbeat, seizures, and potentially life-threatening allergic reactions. It is important to follow the dosage instructions carefully and to monitor for any signs of adverse reactions while taking this medication.

The sarcoplasmic reticulum (SR) is a specialized type of smooth endoplasmic reticulum found in muscle cells, particularly in striated muscles such as skeletal and cardiac muscles. It is a complex network of tubules that surrounds the myofibrils, the contractile elements of the muscle fiber.

The primary function of the sarcoplasmic reticulum is to store calcium ions (Ca2+) and regulate their release during muscle contraction and uptake during muscle relaxation. The SR contains a high concentration of calcium-binding proteins, such as calsequestrin, which help to maintain this storage.

The release of calcium ions from the sarcoplasmic reticulum is triggered by an action potential that travels along the muscle fiber's sarcolemma and into the muscle fiber's interior (the sarcoplasm). This action potential causes the voltage-gated calcium channels in the SR membrane, known as ryanodine receptors, to open, releasing Ca2+ ions into the sarcoplasm.

The increased concentration of Ca2+ ions in the sarcoplasm triggers muscle contraction by binding to troponin, a protein associated with actin filaments, causing a conformational change that exposes the active sites on actin for myosin heads to bind and generate force.

After muscle contraction, the calcium ions must be actively transported back into the sarcoplasmic reticulum by Ca2+ ATPase pumps, also known as sarco(endo)plasmic reticulum calcium ATPases (SERCAs). This process helps to lower the concentration of Ca2+ in the sarcoplasm and allows the muscle fiber to relax.

Overall, the sarcoplasmic reticulum plays a crucial role in excitation-contraction coupling, the process by which action potentials trigger muscle contraction.

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.

Atropine is an anticholinergic drug that blocks the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. It is derived from the belladonna alkaloids, which are found in plants such as deadly nightshade (Atropa belladonna), Jimson weed (Datura stramonium), and Duboisia spp.

In clinical medicine, atropine is used to reduce secretions, increase heart rate, and dilate the pupils. It is often used before surgery to dry up secretions in the mouth, throat, and lungs, and to reduce salivation during the procedure. Atropine is also used to treat certain types of nerve agent and pesticide poisoning, as well as to manage bradycardia (slow heart rate) and hypotension (low blood pressure) caused by beta-blockers or calcium channel blockers.

Atropine can have several side effects, including dry mouth, blurred vision, dizziness, confusion, and difficulty urinating. In high doses, it can cause delirium, hallucinations, and seizures. Atropine should be used with caution in patients with glaucoma, prostatic hypertrophy, or other conditions that may be exacerbated by its anticholinergic effects.

Adrenergic beta-3 receptor agonists are a type of medication that selectively binds to and activates the beta-3 adrenergic receptors. These receptors are found primarily in adipose tissue, where their activation is thought to increase lipolysis (the breakdown of fat) and thermogenesis (the production of heat).

Beta-3 adrenergic receptor agonists have been studied as a potential treatment for obesity and related conditions such as type 2 diabetes. By increasing lipolysis and thermogenesis, these drugs may help to promote weight loss and improve insulin sensitivity. However, their efficacy in humans has not been firmly established, and more research is needed to determine their safety and effectiveness.

Some examples of adrenergic beta-3 receptor agonists include mirabegron, which is approved for the treatment of overactive bladder, and solabegron, which is being studied for its potential use in treating obesity and other metabolic disorders.

Adrenergic beta-1 receptor antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-1 receptors. These receptors are found primarily in the heart and kidneys, where they mediate various physiological responses such as increased heart rate, contractility, and conduction velocity, as well as renin release from the kidneys.

By blocking the action of adrenaline and noradrenaline on these receptors, beta blockers can help to reduce heart rate, lower blood pressure, decrease the force of heart contractions, and improve symptoms of angina (chest pain). They are commonly used to treat a variety of conditions, including hypertension, heart failure, arrhythmias, and certain types of tremors. Examples of beta blockers include metoprolol, atenolol, and propranolol.

Amylases are enzymes that break down complex carbohydrates, such as starch and glycogen, into simpler sugars like maltose, glucose, and maltotriose. There are several types of amylases found in various organisms, including humans.

In humans, amylases are produced by the pancreas and salivary glands. Pancreatic amylase is released into the small intestine where it helps to digest dietary carbohydrates. Salivary amylase, also known as alpha-amylase, is secreted into the mouth and begins breaking down starches in food during chewing.

Deficiency or absence of amylases can lead to difficulties in digesting carbohydrates and may cause symptoms such as bloating, diarrhea, and abdominal pain. Elevated levels of amylase in the blood may indicate conditions such as pancreatitis, pancreatic cancer, or other disorders affecting the pancreas.

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.

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.

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.

A tilt-table test is a diagnostic procedure used to evaluate symptoms of syncope (fainting) or near-syncope. It measures your body's cardiovascular response to changes in position. During the test, you lie on a table that can be tilted to change the angle of your body from horizontal to upright. This simulates what happens when you stand up from a lying down position.

The test monitors heart rate, blood pressure, and oxygen levels while you're in different positions. If you experience symptoms like dizziness or fainting during the test, these can provide clues about the cause of your symptoms. The test is used to diagnose conditions like orthostatic hypotension (a sudden drop in blood pressure when standing), vasovagal syncope (fainting due to an overactive vagus nerve), and other heart rhythm disorders.

Atenolol is a beta-blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and certain types of heart rhythm disorders. It works by blocking the action of certain hormones in the body, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart's workload, lower its rate and force of contractions, and improve blood flow.

Beta-blockers like atenolol are also sometimes used to prevent migraines or to treat symptoms of anxiety, such as rapid heartbeat or tremors. Atenolol is available in immediate-release and extended-release forms, and it is typically taken orally once or twice a day. As with any medication, atenolol can have side effects, including dizziness, fatigue, and gastrointestinal symptoms, and it may interact with other medications or medical conditions. It is important to use atenolol only under the supervision of a healthcare provider.

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.

Prostaglandin E (PGE) is a type of prostaglandin, which is a group of lipid compounds that are synthesized in the body from fatty acids and have diverse hormone-like effects. Prostaglandins are not actually hormones, but are similar to them in that they act as chemical messengers that have specific effects on certain cells.

Prostaglandin E is one of the most abundant prostaglandins in the body and has a variety of physiological functions. It is involved in the regulation of inflammation, pain perception, fever, and smooth muscle contraction. Prostaglandin E also plays a role in the regulation of blood flow, platelet aggregation, and gastric acid secretion.

Prostaglandin E is synthesized from arachidonic acid, which is released from cell membranes by the action of enzymes called phospholipases. Once formed, prostaglandin E binds to specific receptors on the surface of cells, leading to a variety of intracellular signaling events that ultimately result in changes in cell behavior.

Prostaglandin E is used medically in the treatment of several conditions, including dysmenorrhea (painful menstruation), postpartum hemorrhage, and patent ductus arteriosus (a congenital heart defect). It is also used as a diagnostic tool in the evaluation of kidney function.

Calcium-binding proteins (CaBPs) are a diverse group of proteins that have the ability to bind calcium ions (Ca^2+^) with high affinity and specificity. They play crucial roles in various cellular processes, including signal transduction, muscle contraction, neurotransmitter release, and protection against oxidative stress.

The binding of calcium ions to these proteins induces conformational changes that can either activate or inhibit their functions. Some well-known CaBPs include calmodulin, troponin C, S100 proteins, and parvalbumins. These proteins are essential for maintaining calcium homeostasis within cells and for mediating the effects of calcium as a second messenger in various cellular signaling pathways.

An action potential is a brief electrical signal that travels along the membrane of a nerve cell (neuron) or muscle cell. It is initiated by a rapid, localized change in the permeability of the cell membrane to specific ions, such as sodium and potassium, resulting in a rapid influx of sodium ions and a subsequent efflux of potassium ions. This ion movement causes a brief reversal of the electrical potential across the membrane, which is known as depolarization. The action potential then propagates along the cell membrane as a wave, allowing the electrical signal to be transmitted over long distances within the body. Action potentials play a crucial role in the communication and functioning of the nervous system and muscle tissue.

Electrocardiography (ECG or EKG) is a medical procedure that records the electrical activity of the heart. It provides a graphic representation of the electrical changes that occur during each heartbeat. The resulting tracing, called an electrocardiogram, can reveal information about the heart's rate and rhythm, as well as any damage to its cells or abnormalities in its conduction system.

During an ECG, small electrodes are placed on the skin of the chest, arms, and legs. These electrodes detect the electrical signals produced by the heart and transmit them to a machine that amplifies and records them. The procedure is non-invasive, painless, and quick, usually taking only a few minutes.

ECGs are commonly used to diagnose and monitor various heart conditions, including arrhythmias, coronary artery disease, heart attacks, and electrolyte imbalances. They can also be used to evaluate the effectiveness of certain medications or treatments.

Hemodynamics is the study of how blood flows through the cardiovascular system, including the heart and the vascular network. It examines various factors that affect blood flow, such as blood volume, viscosity, vessel length and diameter, and pressure differences between different parts of the circulatory system. Hemodynamics also considers the impact of various physiological and pathological conditions on these variables, and how they in turn influence the function of vital organs and systems in the body. It is a critical area of study in fields such as cardiology, anesthesiology, and critical care medicine.

Muscarinic receptors are a type of G protein-coupled receptor (GPCR) that bind to the neurotransmitter acetylcholine. They are found in various organ systems, including the nervous system, cardiovascular system, and respiratory system. Muscarinic receptors are activated by muscarine, a type of alkaloid found in certain mushrooms, and are classified into five subtypes (M1-M5) based on their pharmacological properties and signaling pathways.

Muscarinic receptors play an essential role in regulating various physiological functions, such as heart rate, smooth muscle contraction, glandular secretion, and cognitive processes. Activation of M1, M3, and M5 muscarinic receptors leads to the activation of phospholipase C (PLC) and the production of inositol trisphosphate (IP3) and diacylglycerol (DAG), which increase intracellular calcium levels and activate protein kinase C (PKC). Activation of M2 and M4 muscarinic receptors inhibits adenylyl cyclase, reducing the production of cAMP and modulating ion channel activity.

In summary, muscarinic receptors are a type of GPCR that binds to acetylcholine and regulates various physiological functions in different organ systems. They are classified into five subtypes based on their pharmacological properties and signaling pathways.

Oxotremorine is a muscarinic receptor agonist, which means it binds to and activates muscarinic acetylcholine receptors. These receptors are found in the central and peripheral nervous system and are involved in various physiological functions, including cognition, motivation, reward, motor control, and sensory processing.

Oxotremorine is primarily used in research settings to study the role of muscarinic receptors in different physiological processes and diseases. It has been shown to produce effects similar to those caused by natural neurotransmitter acetylcholine, such as increased salivation, sweating, and gastrointestinal motility.

In addition, oxotremorine has been investigated for its potential therapeutic use in the treatment of various neurological disorders, including Alzheimer's disease, Parkinson's disease, and schizophrenia. However, its clinical use is limited due to its side effects, such as nausea, vomiting, diarrhea, and abdominal cramps.

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.

Alprostadil is a synthetic form of prostaglandin E1, which is a naturally occurring substance in the body. It is used medically for several purposes, including:

1. Treatment of erectile dysfunction (ED): Alprostadil can be administered directly into the penis as an injection or inserted as a suppository into the urethra to help improve blood flow and achieve an erection.
2. Prevention of closure of a patent ductus arteriosus (PDA) in premature infants: Alprostadil is used to keep the PDA open, allowing for proper blood flow between the pulmonary artery and the aorta, until surgery can be performed.
3. Treatment of peripheral arterial disease: Alprostadil can be administered intravenously to help improve blood flow in patients with peripheral arterial disease.

Alprostadil works by relaxing smooth muscle tissue in blood vessels, which increases blood flow and helps to lower blood pressure. It may also have other effects on the body, such as reducing the risk of blood clots and modulating inflammation.

It is important to note that alprostadil should only be used under the supervision of a healthcare provider, as it can have serious side effects if not used properly.

Butoxamine is a pharmaceutical drug that acts as an antagonist or blocker for β2-adrenergic receptors. These receptors are found in various tissues throughout the body and play a role in mediating the effects of catecholamines such as adrenaline and noradrenaline.

Butoxamine is primarily used in research settings to study the functions of β2-adrenergic receptors and their signaling pathways. It has been used to investigate the role of these receptors in various physiological processes, including airway smooth muscle relaxation, lipolysis, and insulin secretion.

It is important to note that Butoxamine is not approved for use in humans as a therapeutic agent, and its use is restricted to research purposes only.

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.

GTP-binding protein alpha subunits, Gi-Go, are a type of heterotrimeric G proteins that play a crucial role in signal transduction pathways associated with many hormones and neurotransmitters. These G proteins are composed of three subunits: alpha, beta, and gamma. The "Gi-Go" specifically refers to the alpha subunit of these G proteins, which can exist in two isoforms, Gi and Go.

When a G protein-coupled receptor (GPCR) is activated by an agonist, it undergoes a conformational change that allows it to act as a guanine nucleotide exchange factor (GEF). The GEF activity of the GPCR promotes the exchange of GDP for GTP on the alpha subunit of the heterotrimeric G protein. Once GTP is bound, the alpha subunit dissociates from the beta-gamma dimer and can then interact with downstream effectors to modulate various cellular responses.

The Gi-Go alpha subunits are inhibitory in nature, meaning that they typically inhibit the activity of adenylyl cyclase, an enzyme responsible for converting ATP to cAMP. This reduction in cAMP levels can have downstream effects on various cellular processes, such as gene transcription, ion channel regulation, and metabolic pathways.

In summary, GTP-binding protein alpha subunits, Gi-Go, are heterotrimeric G proteins that play an essential role in signal transduction pathways by modulating adenylyl cyclase activity upon GPCR activation, ultimately influencing various cellular responses through cAMP regulation.

Lipid mobilization, also known as lipolysis, is the process by which fat cells (adipocytes) break down stored triglycerides into free fatty acids and glycerol, which can then be released into the bloodstream and used for energy by the body's cells. This process is regulated by hormones such as adrenaline, noradrenaline, glucagon, and cortisol, which activate enzymes in the fat cell that catalyze the breakdown of triglycerides. Lipid mobilization is an important physiological response to fasting, exercise, and stress, and plays a key role in maintaining energy homeostasis in the body.

I'm not aware of any recognized medical term or condition specifically referred to as "turkeys." The term "turkey" is most commonly used in a non-medical context to refer to the large, bird-like domesticated fowl native to North America, scientifically known as Meleagris gallopavo.

However, if you are referring to a medical condition called "turkey neck," it is a colloquial term used to describe sagging or loose skin around the neck area, which can resemble a turkey's wattle. This condition is not a formal medical diagnosis but rather a descriptive term for an aesthetic concern some people may have about their appearance.

If you meant something else by "turkeys," please provide more context so I can give you a more accurate answer.

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.

Ethanolamines are a class of organic compounds that contain an amino group (-NH2) and a hydroxyl group (-OH) attached to a carbon atom. They are derivatives of ammonia (NH3) in which one or two hydrogen atoms have been replaced by a ethanol group (-CH2CH2OH).

The most common ethanolamines are:

* Monethanolamine (MEA), also called 2-aminoethanol, with the formula HOCH2CH2NH2.
* Diethanolamine (DEA), also called 2,2'-iminobisethanol, with the formula HOCH2CH2NHCH2CH2OH.
* Triethanolamine (TEA), also called 2,2',2''-nitrilotrisethanol, with the formula N(CH2CH2OH)3.

Ethanolamines are used in a wide range of industrial and consumer products, including as solvents, emulsifiers, detergents, pharmaceuticals, and personal care products. They also have applications as intermediates in the synthesis of other chemicals. In the body, ethanolamines play important roles in various biological processes, such as neurotransmission and cell signaling.

The submandibular glands are one of the major salivary glands in the human body. They are located beneath the mandible (jawbone) and produce saliva that helps in digestion, lubrication, and protection of the oral cavity. The saliva produced by the submandibular glands contains enzymes like amylase and mucin, which aid in the digestion of carbohydrates and provide moisture to the mouth and throat. Any medical condition or disease that affects the submandibular gland may impact its function and could lead to problems such as dry mouth (xerostomia), swelling, pain, or infection.

Bradycardia is a medical term that refers to an abnormally slow heart rate, typically defined as a resting heart rate of less than 60 beats per minute in adults. While some people, particularly well-trained athletes, may have a naturally low resting heart rate, bradycardia can also be a sign of an underlying health problem.

There are several potential causes of bradycardia, including:

* Damage to the heart's electrical conduction system, such as from heart disease or aging
* Certain medications, including beta blockers, calcium channel blockers, and digoxin
* Hypothyroidism (underactive thyroid gland)
* Sleep apnea
* Infection of the heart (endocarditis or myocarditis)
* Infiltrative diseases such as amyloidosis or sarcoidosis

Symptoms of bradycardia can vary depending on the severity and underlying cause. Some people with bradycardia may not experience any symptoms, while others may feel weak, fatigued, dizzy, or short of breath. In severe cases, bradycardia can lead to fainting, confusion, or even cardiac arrest.

Treatment for bradycardia depends on the underlying cause. If a medication is causing the slow heart rate, adjusting the dosage or switching to a different medication may help. In other cases, a pacemaker may be necessary to regulate the heart's rhythm. It is important to seek medical attention if you experience symptoms of bradycardia, as it can be a sign of a serious underlying condition.

Cardiac arrhythmias are abnormal heart rhythms that result from disturbances in the electrical conduction system of the heart. The heart's normal rhythm is controlled by an electrical signal that originates in the sinoatrial (SA) node, located in the right atrium. This signal travels through the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood throughout the body.

An arrhythmia occurs when there is a disruption in this electrical pathway or when the heart's natural pacemaker produces an abnormal rhythm. This can cause the heart to beat too fast (tachycardia), too slow (bradycardia), or irregularly.

There are several types of cardiac arrhythmias, including:

1. Atrial fibrillation: A rapid and irregular heartbeat that starts in the atria (the upper chambers of the heart).
2. Atrial flutter: A rapid but regular heartbeat that starts in the atria.
3. Supraventricular tachycardia (SVT): A rapid heartbeat that starts above the ventricles, usually in the atria or AV node.
4. Ventricular tachycardia: A rapid and potentially life-threatening heart rhythm that originates in the ventricles.
5. Ventricular fibrillation: A chaotic and disorganized electrical activity in the ventricles, which can be fatal if not treated immediately.
6. Heart block: A delay or interruption in the conduction of electrical signals from the atria to the ventricles.

Cardiac arrhythmias can cause various symptoms, such as palpitations, dizziness, shortness of breath, chest pain, and fatigue. In some cases, they may not cause any symptoms and go unnoticed. However, if left untreated, certain types of arrhythmias can lead to serious complications, including stroke, heart failure, or even sudden cardiac death.

Treatment for cardiac arrhythmias depends on the type, severity, and underlying causes. Options may include lifestyle changes, medications, cardioversion (electrical shock therapy), catheter ablation, implantable devices such as pacemakers or defibrillators, and surgery. It is essential to consult a healthcare professional for proper evaluation and management of cardiac arrhythmias.

Procaterol is not a medication that has been approved by the US Food and Drug Administration (FDA) for use in the United States. However, it is a medication that is available in some other countries as a bronchodilator, which is a type of medication that is used to open up the airways in the lungs and make it easier to breathe.

Procaterol belongs to a class of medications called long-acting beta-agonists (LABAs). LABAs work by relaxing the muscles in the airways and increasing the size of the airways, which makes it easier for air to flow in and out of the lungs. Procaterol is often used to prevent symptoms of chronic obstructive pulmonary disease (COPD), such as shortness of breath and coughing.

It's important to note that procaterol has been associated with an increased risk of asthma-related deaths, so it should only be used under the close supervision of a healthcare professional and should not be used in people with asthma who are not also using a corticosteroid inhaler.

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.

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.

Adipocytes are specialized cells that comprise adipose tissue, also known as fat tissue. They are responsible for storing energy in the form of lipids, particularly triglycerides, and releasing energy when needed through a process called lipolysis. There are two main types of adipocytes: white adipocytes and brown adipocytes. White adipocytes primarily store energy, while brown adipocytes dissipate energy as heat through the action of uncoupling protein 1 (UCP1).

In addition to their role in energy metabolism, adipocytes also secrete various hormones and signaling molecules that contribute to whole-body homeostasis. These include leptin, adiponectin, resistin, and inflammatory cytokines. Dysregulation of adipocyte function has been implicated in the development of obesity, insulin resistance, type 2 diabetes, and cardiovascular disease.

**Prazosin** is an antihypertensive drug, which belongs to the class of medications called alpha-blockers. It works by relaxing the muscles in the blood vessels, which helps to lower blood pressure and improve blood flow. Prazosin is primarily used to treat high blood pressure (hypertension), but it may also be used for the management of symptoms related to enlarged prostate (benign prostatic hyperplasia).

In a medical definition context:

Prazosin: A selective α1-adrenergic receptor antagonist, used in the treatment of hypertension and benign prostatic hyperplasia. It acts by blocking the action of norepinephrine on the smooth muscle of blood vessels, resulting in vasodilation and decreased peripheral vascular resistance. This leads to a reduction in blood pressure and an improvement in urinary symptoms associated with an enlarged prostate.

Sympatholytics are a class of drugs that block the action of the sympathetic nervous system, which is the part of the autonomic nervous system responsible for preparing the body for the "fight or flight" response. Sympatholytics achieve this effect by binding to and blocking alpha-adrenergic receptors or beta-adrenergic receptors located in various organs throughout the body, including the heart, blood vessels, lungs, gastrointestinal tract, and urinary system.

Examples of sympatholytic drugs include:

* Alpha blockers (e.g., prazosin, doxazosin)
* Beta blockers (e.g., propranolol, metoprolol)
* Centrally acting sympatholytics (e.g., clonidine, methyldopa)

Sympatholytics are used to treat a variety of medical conditions, including hypertension, angina, heart failure, arrhythmias, and certain neurological disorders. They may also be used to manage symptoms associated with anxiety or withdrawal from alcohol or other substances.

A muscarinic M2 receptor is a type of G protein-coupled receptor (GPCR) that binds to the neurotransmitter acetylcholine. It is one of five subtypes of muscarinic receptors (M1-M5) and is widely distributed throughout the body, particularly in the heart, smooth muscle, and exocrine glands.

The M2 receptor is coupled to the G protein inhibitory Gαi/o, which inhibits adenylyl cyclase activity and reduces intracellular cAMP levels. This leads to a variety of physiological responses, including negative chronotropy (slowing of heart rate) and negative inotropy (decreased contractility) in the heart, relaxation of smooth muscle in the bronchioles and gastrointestinal tract, and inhibition of exocrine gland secretion.

The M2 receptor is an important target for drugs used to treat a variety of conditions, including cardiovascular diseases, asthma, chronic obstructive pulmonary disease (COPD), and gastrointestinal disorders. Anticholinergic drugs such as atropine and ipratropium bind to the M2 receptor and block its activity, while muscarinic agonists such as bethanechol activate the receptor.

Salivary proteins and peptides refer to the diverse group of molecules that are present in saliva, which is the clear, slightly alkaline fluid produced by the salivary glands in the mouth. These proteins and peptides play a crucial role in maintaining oral health and contributing to various physiological functions.

Some common types of salivary proteins and peptides include:

1. **Mucins**: These are large, heavily glycosylated proteins that give saliva its viscous quality. They help to lubricate the oral cavity, protect the mucosal surfaces, and aid in food bolus formation.
2. **Amylases**: These enzymes break down carbohydrates into simpler sugars, initiating the digestive process even before food reaches the stomach.
3. **Proline-rich proteins (PRPs)**: PRPs contribute to the buffering capacity of saliva and help protect against tooth erosion by forming a protective layer on tooth enamel.
4. **Histatins**: These are small cationic peptides with antimicrobial properties, playing a significant role in maintaining oral microbial homeostasis and preventing dental caries.
5. **Lactoferrin**: An iron-binding protein that exhibits antibacterial, antifungal, and anti-inflammatory activities, contributing to the overall oral health.
6. **Statherin and Cystatins**: These proteins regulate calcium phosphate precipitation, preventing dental calculus formation and maintaining tooth mineral homeostasis.

Salivary proteins and peptides have attracted significant interest in recent years due to their potential diagnostic and therapeutic applications. Alterations in the composition of these molecules can provide valuable insights into various oral and systemic diseases, making them promising biomarkers for disease detection and monitoring.

The sinoatrial (SA) node, also known as the sinus node, is the primary pacemaker of the heart. It is a small bundle of specialized cardiac conduction tissue located in the upper part of the right atrium, near the entrance of the superior vena cava. The SA node generates electrical impulses that initiate each heartbeat, causing the atria to contract and pump blood into the ventricles. This process is called sinus rhythm.

The SA node's electrical activity is regulated by the autonomic nervous system, which can adjust the heart rate in response to changes in the body's needs, such as during exercise or rest. The SA node's rate of firing determines the heart rate, with a normal resting heart rate ranging from 60 to 100 beats per minute.

If the SA node fails to function properly or its electrical impulses are blocked, other secondary pacemakers in the heart may take over, resulting in abnormal heart rhythms called arrhythmias.

The heart conduction system is a group of specialized cardiac muscle cells that generate and conduct electrical impulses to coordinate the contraction of the heart chambers. The main components of the heart conduction system include:

1. Sinoatrial (SA) node: Also known as the sinus node, it is located in the right atrium near the entrance of the superior vena cava and functions as the primary pacemaker of the heart. It sets the heart rate by generating electrical impulses at regular intervals.
2. Atrioventricular (AV) node: Located in the interatrial septum, near the opening of the coronary sinus, it serves as a relay station for electrical signals between the atria and ventricles. The AV node delays the transmission of impulses to allow the atria to contract before the ventricles.
3. Bundle of His: A bundle of specialized cardiac muscle fibers that conducts electrical impulses from the AV node to the ventricles. It divides into two main branches, the right and left bundle branches, which further divide into smaller Purkinje fibers.
4. Right and left bundle branches: These are extensions of the Bundle of His that transmit electrical impulses to the respective right and left ventricular myocardium. They consist of specialized conducting tissue with large diameters and minimal resistance, allowing for rapid conduction of electrical signals.
5. Purkinje fibers: Fine, branching fibers that arise from the bundle branches and spread throughout the ventricular myocardium. They are responsible for transmitting electrical impulses to the working cardiac muscle cells, triggering coordinated ventricular contraction.

In summary, the heart conduction system is a complex network of specialized muscle cells responsible for generating and conducting electrical signals that coordinate the contraction of the atria and ventricles, ensuring efficient blood flow throughout the body.

Syncope is a medical term defined as a transient, temporary loss of consciousness and postural tone due to reduced blood flow to the brain. It's often caused by a drop in blood pressure, which can be brought on by various factors such as dehydration, emotional stress, prolonged standing, or certain medical conditions like heart diseases, arrhythmias, or neurological disorders.

During a syncope episode, an individual may experience warning signs such as lightheadedness, dizziness, blurred vision, or nausea before losing consciousness. These episodes usually last only a few minutes and are followed by a rapid, full recovery. However, if left untreated or undiagnosed, recurrent syncope can lead to severe injuries from falls or even life-threatening conditions related to the underlying cause.

Adrenergic agents are a class of drugs that bind to and activate adrenergic receptors, which are cell surface receptors found in the nervous system and other tissues. These receptors are activated by neurotransmitters such as norepinephrine and epinephrine (also known as adrenaline), which are released by the sympathetic nervous system in response to stress or excitement.

Adrenergic agents can be classified based on their mechanism of action and the specific receptors they bind to. There are two main types of adrenergic receptors: alpha and beta receptors, each with several subtypes. Some adrenergic agents bind to both alpha and beta receptors, while others are selective for one or the other.

Adrenergic agents have a wide range of therapeutic uses, including the treatment of asthma, cardiovascular diseases, glaucoma, and neurological disorders. They can also be used as diagnostic tools to test the function of the sympathetic nervous system. Some examples of adrenergic agents include:

* Alpha-agonists: These drugs bind to alpha receptors and cause vasoconstriction (narrowing of blood vessels), which can be useful in the treatment of hypotension (low blood pressure) or nasal congestion. Examples include phenylephrine and oxymetazoline.
* Alpha-antagonists: These drugs block the action of alpha receptors, leading to vasodilation (widening of blood vessels) and a decrease in blood pressure. Examples include prazosin and doxazosin.
* Beta-agonists: These drugs bind to beta receptors and cause bronchodilation (opening of the airways), increased heart rate, and increased force of heart contractions. They are used in the treatment of asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders. Examples include albuterol and salmeterol.
* Beta-antagonists: These drugs block the action of beta receptors, leading to a decrease in heart rate, blood pressure, and bronchodilation. They are used in the treatment of hypertension, angina (chest pain), and heart failure. Examples include metoprolol and atenolol.
* Nonselective alpha- and beta-antagonists: These drugs block both alpha and beta receptors and are used in the treatment of hypertension, angina, and heart failure. Examples include labetalol and carvedilol.

I couldn't find a medical definition for "Depression, Chemical" as it is not a recognized medical term. However, I can provide you with information about chemical imbalances in the brain that are associated with depression.

Major depressive disorder (MDD), commonly referred to as depression, is believed to be caused by a combination of genetic, environmental, and physiological factors. While there is no definitive evidence that depression is solely caused by a "chemical imbalance," neurotransmitter irregularities in the brain are associated with depressive symptoms. Neurotransmitters are chemical messengers that transmit signals in the brain and other parts of the body. Some of the primary neurotransmitters involved in mood regulation include serotonin, norepinephrine, and dopamine.

In depression, it is thought that there may be alterations in the functioning of these neurotransmitter systems, leading to an imbalance. For example:

1. Serotonin: Low levels of serotonin are associated with depressive symptoms. Selective serotonin reuptake inhibitors (SSRIs), a common class of antidepressants, work by increasing the availability of serotonin in the synapse (the space between neurons) to improve communication between brain cells.
2. Norepinephrine: Imbalances in norepinephrine levels can contribute to depressive symptoms and anxiety. Norepinephrine reuptake inhibitors (NRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs) are medications that target norepinephrine to help alleviate depression.
3. Dopamine: Deficiencies in dopamine can lead to depressive symptoms, anhedonia (the inability to feel pleasure), and motivation loss. Some antidepressants, like bupropion, work by increasing dopamine levels in the brain.

In summary, while "Chemical Depression" is not a recognized medical term, chemical imbalances in neurotransmitter systems are associated with depressive symptoms. However, depression is a complex disorder that cannot be solely attributed to a single cause or a simple chemical imbalance. It is essential to consider multiple factors when diagnosing and treating depression.

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.

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.

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.

Virulence factors in Bordetella pertussis, the bacterium that causes whooping cough, refer to the characteristics or components of the organism that contribute to its ability to cause disease. These virulence factors include:

1. Pertussis Toxin (PT): A protein exotoxin that inhibits the immune response and affects the nervous system, leading to the characteristic paroxysmal cough of whooping cough.
2. Adenylate Cyclase Toxin (ACT): A toxin that increases the levels of cAMP in host cells, disrupting their function and contributing to the pathogenesis of the disease.
3. Filamentous Hemagglutinin (FHA): A surface protein that allows the bacterium to adhere to host cells and evade the immune response.
4. Fimbriae: Hair-like appendages on the surface of the bacterium that facilitate adherence to host cells.
5. Pertactin (PRN): A surface protein that also contributes to adherence and is a common component of acellular pertussis vaccines.
6. Dermonecrotic Toxin: A toxin that causes localized tissue damage and necrosis, contributing to the inflammation and symptoms of whooping cough.
7. Tracheal Cytotoxin: A toxin that damages ciliated epithelial cells in the respiratory tract, impairing mucociliary clearance and increasing susceptibility to infection.

These virulence factors work together to enable Bordetella pertussis to colonize the respiratory tract, evade the host immune response, and cause the symptoms of whooping cough.

Adrenergic antagonists, also known as beta blockers or sympatholytic drugs, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on the body. These neurotransmitters are part of the sympathetic nervous system and play a role in the "fight or flight" response, increasing heart rate, blood pressure, and respiratory rate.

Adrenergic antagonists work by binding to beta-adrenergic receptors in the body, preventing the neurotransmitters from activating them. This results in a decrease in heart rate, blood pressure, and respiratory rate. These medications are used to treat various conditions such as hypertension, angina, heart failure, arrhythmias, glaucoma, and anxiety disorders.

There are two types of adrenergic antagonists: beta blockers and alpha blockers. Beta blockers selectively bind to beta-adrenergic receptors, while alpha blockers bind to alpha-adrenergic receptors. Some medications, such as labetalol, have both beta and alpha blocking properties.

It is important to note that adrenergic antagonists can interact with other medications and may cause side effects, so it is essential to use them under the guidance of a healthcare professional.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

Pertussis toxin is an exotoxin produced by the bacterium Bordetella pertussis, which is responsible for causing whooping cough in humans. This toxin has several effects on the host organism, including:

1. Adenylyl cyclase activation: Pertussis toxin enters the host cell and modifies a specific G protein (Gαi), leading to the continuous activation of adenylyl cyclase. This results in increased levels of intracellular cAMP, which disrupts various cellular processes.
2. Inhibition of immune response: Pertussis toxin impairs the host's immune response by inhibiting the migration and function of immune cells like neutrophils and macrophages. It also interferes with antigen presentation and T-cell activation, making it difficult for the body to clear the infection.
3. Increased inflammation: The continuous activation of adenylyl cyclase by pertussis toxin leads to increased production of proinflammatory cytokines, contributing to the severe coughing fits and other symptoms associated with whooping cough.

Pertussis toxin is an essential virulence factor for Bordetella pertussis, and its effects contribute significantly to the pathogenesis of whooping cough. Vaccination against pertussis includes inactivated or genetically detoxified forms of pertussis toxin, which provide immunity without causing disease symptoms.

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.

The ciliary body is a part of the eye's internal structure that is located between the choroid and the iris. It is composed of muscle tissue and is responsible for adjusting the shape of the lens through a process called accommodation, which allows the eye to focus on objects at varying distances. Additionally, the ciliary body produces aqueous humor, the clear fluid that fills the anterior chamber of the eye and helps to nourish the eye's internal structures. The ciliary body is also responsible for maintaining the shape and position of the lens within the eye.

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.

The sympathetic nervous system (SNS) is a part of the autonomic nervous system that operates largely below the level of consciousness, and it functions to produce appropriate physiological responses to perceived danger. It's often associated with the "fight or flight" response. The SNS uses nerve impulses to stimulate target organs, causing them to speed up (e.g., increased heart rate), prepare for action, or otherwise respond to stressful situations.

The sympathetic nervous system is activated due to stressful emotional or physical situations and it prepares the body for immediate actions. It dilates the pupils, increases heart rate and blood pressure, accelerates breathing, and slows down digestion. The primary neurotransmitter involved in this system is norepinephrine (also known as noradrenaline).

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.

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.

Pracitolol is not a medical condition, it's a medication. Practolol is a beta blocker drug that is primarily used to treat various cardiovascular conditions such as hypertension (high blood pressure), angina (chest pain due to reduced blood flow to the heart), and certain types of arrhythmias (irregular heart rhythms).

Beta blockers like practolol work by blocking the effects of certain hormones, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart rate, lower blood pressure, and decrease the force of heart contractions, which can improve overall cardiovascular function and reduce the risk of heart-related complications.

It's important to note that practolol is not commonly used in clinical practice due to its association with a rare but serious side effect known as the "practolol syndrome." This condition can cause various symptoms such as dry eyes, skin rashes, and abnormalities of the thyroid gland. As a result, other beta blockers are generally preferred over practolol for the treatment of cardiovascular conditions.

Dihydroergotoxine is a semi-synthetic ergot alkaloid, which is derived from the ergot fungus (Claviceps purpurea). It is a mixture of four dihydrogenated ergot alkaloids: dihydroergocristine, dihydroergotamine, dihydroergotoxine, and dihydroalphaergocryptine.

Dihydroergotoxine has been used in the treatment of various medical conditions, including peripheral and cerebral vascular insufficiency, migraine headaches, and orthostatic hypotension. It works by stimulating the release of neurotransmitters such as serotonin, dopamine, and norepinephrine, which help to improve blood flow and reduce symptoms associated with these conditions.

It is important to note that dihydroergotoxine can have serious side effects, including ergotism, a condition characterized by vasoconstriction, muscle cramps, and gangrene. It should be used with caution and under the close supervision of a healthcare provider.

21 January 2015). "Isoproterenol acts as a biased agonist of the alpha-1A-adrenoceptor that selectively activates the MAPK/ERK ... Isoprenaline, or isoproterenol, is a medication used for the treatment of bradycardia (slow heart rate), heart block, and ... Isoproterenol has been reported to cause insulin resistance leading to diabetic ketoacidosis. The adverse effects of ... The plasma half-life for isoproterenol is approximately two to five minutes. It is degraded enzymatically via catechol O- ...
In one study, a patient with bilateral insula and ACC damage was given isoproterenol as a method of exciting the cardiovascular ... Khalsa, S.S.; Rudrauf, D.; Sandesara, C.; Olshansky, B.; Tranel, D. (2009). "Bolus isoproterenol infusions provide a reliable ... This can be done pharmacologically using adrenaline-like drugs, such as isoproterenol, which mimic activation of the ... "Isoproterenol-induced panic attacks". Biological Psychiatry. 24 (8): 891-902. doi:10.1016/0006-3223(88)90224-7. PMID 3069135. ...
In 1940 isoproterenol (isoprenaline) was discovered. This compound had a similar effect as adrenalin but fewer side effects ... In 1949 isoproterenol was used generally to treat asthma patients, given sublingually or inhaled. The first pressurized metered ... In 1961 orciprenaline, a longer acting β2-agonist was found, but it was not as potent as isoproterenol. Orciprenaline does not ... Albuterol and terbutaline gave fewer side effects, such as increased heart rate, than isoproterenol. The pharmaceutical company ...
It is methylenedioxyphenyl-isoproterenol. The Para-Methoxyamphetamine (PMA) analog is twice the potency as the tenamfetamine ...
It was initially made from isoproterenol. Dobutamine is used to treat acute but potentially reversible heart failure, such as ... dobutamine tends to produce less tachycardia and peripheral vascular effects than agents such as epinephrine and isoproterenol ...
Other examples include phenylephrine, isoproterenol, and dobutamine. Stimulation of the D1 receptor by dopaminergic agonists ...
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Endogenous sulfur dioxide also diminishes myocardial damage, caused by isoproterenol adrenergic hyperstimulation, and ... "Endogenous sulfur dioxide protects against isoproterenol-induced myocardial injury and increases myocardial antioxidant ...
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"Coconut haustorium maintains cardiac integrity and alleviates oxidative stress in rats subjected to isoproterenol-induced ...
... intrinsic activity compared to the gold standard isoprenaline/isoproterenol). Its half maximal effective concentration (EC50) ...
"Cardioprotective effect of 'Khamira Abresham Hakim Arshad Wala' a unani formulation in isoproterenol-induced myocardial ...
"Effects of prolonged infusions of atrial natriuretic peptide and isoproterenol on the mechanical and endocrine function of ...
Agonist activity at human NPYY4 receptor expressed in HEK293 cells assessed as decrease in isoproterenol-induced cAMP level ...
Find information on Isoproterenol (Isuprel) in Daviss Drug Guide including dosage, side effects, interactions, nursing ... "Isoproterenol." Daviss Drug Guide, 18th ed., F.A. Davis Company, 2023. Emergency Central, emergency.unboundmedicine.com/ ... emergency/view/Davis-Drug-Guide/51419/all/isoproterenol. Vallerand AHA, Sanoski CAC, Quiring CC. Isoproterenol. Daviss Drug ... Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023). Isoproterenol. In Daviss Drug Guide (18th ed.). F.A. Davis Company. ...
Sevoflurano Interactuando con Isoproterenol. Efecto.. Aumento del efecto arritmogénico de isoproterenol. No administrar. ...
ISOPROTERENOL (isoproterenol hydrochloride) injection, solution. NDC Code(s): 69097-521-31, 69097-522-35 *Packager: Cipla USA ... ISOPROTERENOL HYDROCHLORIDE (isoproterenol hydrochloride) injection. NDC Code(s): 42571-294-78, 42571-294-79, 42571-330-80 * ... ISOPROTERENOL HYDROCHLORIDE injection, solution. NDC Code(s): 69918-731-10, 69918-735-10 *Packager: Amring Pharmaceuticals Inc. ... ISOPROTERENOL HYDROCHLORIDE injection, solution. NDC Code(s): 10702-364-05, 10702-364-51 *Packager: KVK-Tech, Inc. ...
Study of the therapeutic and cardioprotective effects of herbal extracts on isoproterenol-induced myocardial necrosis in rats ... We will study the myocardium of rats,using a classical model of catecholamine induced-injury, isoproterenol (a synthetic ... Cardioprotective and therapeutic effects of herbal extracts on isoproterenol-induc.... Study of therapeutic and ... Study of the therapeutic and cardioprotective effects of herbal extracts on isoproterenol-induced myocardial necrosis in rats. ...
In addition, the ability of the cerebellum to respond to trophic stimulation by a beta-adrenergic agonist, isoproterenol, was ... Effects of neonatal treatment with 6-aminonicotinamide on basal and isoproterenol-stimulated ornithine decarboxylase activity ... "Effects of neonatal treatment with 6-aminonicotinamide on basal and isoproterenol-stimulated ornithine decarboxylase activity ... Effects of neonatal treatment with 6-aminonicotinamide on basal and isoproterenol-stimulated ornithine decarboxylase activity ...
21 January 2015). "Isoproterenol acts as a biased agonist of the alpha-1A-adrenoceptor that selectively activates the MAPK/ERK ... Isoprenaline, or isoproterenol, is a medication used for the treatment of bradycardia (slow heart rate), heart block, and ... Isoproterenol has been reported to cause insulin resistance leading to diabetic ketoacidosis. The adverse effects of ... The plasma half-life for isoproterenol is approximately two to five minutes. It is degraded enzymatically via catechol O- ...
... in isoproterenol (ISO) induced AMI focusing on autophagy & PI3K/Akt signaling. Seventy male Albino rats were divided into ... Isoproterenol AMI model is a widely and commonly used experimental model of AMI [24, 39]. Isoproterenol is a synthetic ... ISO: Isoproterenol induced AMI group (85 mg/kg isoproterenol), LY294002 + ISO: PI3K inhibitor group (0.3 mg/kg), DATS+ISO: ... ISO: Isoproterenol induced AMI group (85 mg/kg isoproterenol), LY294002 + ISO: PI3K inhibitor group (0.3 mg/kg), DATS+ISO: ...
Isoproterenol (isuprel ®) Beta1/Beta2 agonist. Dosing (adults): Cardiac arrhythmias: Initial: 2 mcg/minute IV; titrate to ...
Adrenergic bronchodilators are inhaled medicines that help open up the airways. They are used to treat asthma and chronic bronchitis. Adrenergic bronchodilator overdose occurs when someone accidentally
Data for: Genistein reverses isoproterenol-induced cardiac hypertrophy by regulating miR-451/TIMP2. Published:. 26 February ...
Isoproterenol. In: Ciccone CD. Ciccone C.D.(Ed.),Ed. Charles D. Ciccone.eds. Daviss Drug Guide for Rehabilitation ... "Isoproterenol." Daviss Drug Guide for Rehabilitation Professionals Ciccone CD. Ciccone C.D.(Ed.),Ed. Charles D. Ciccone. ... Isoproterenol. Ciccone CD. Ciccone C.D.(Ed.),Ed. Charles D. Ciccone. (2016). Daviss Drug Guide for Rehabilitation ... or increased BP occur more commonly with isoproterenol compared to other bronchodilators because isoproterenol stimulates beta- ...
Age-dependence of isoproterenol-induced dna synthesis in submandibular glands of balb/c mice. ...
The syndrome of inappropriate antidiuretic hormone (ADH) secretion (SIADH) is defined by the hyponatremia and hypo-osmolality resulting from inappropriate, continued secretion or action of the hormone despite normal or increased plasma volume, which results in impaired water excretion. The key to understanding the pathophysiology, signs, symp...
Isoproterenol / therapeutic use * Methylprednisolone / therapeutic use * Middle Aged * Prednisone / therapeutic use * Pulmonary ...
Isoproterenol inhalation. 6 (7.5). 0. 6 (35.3). ,0.01. Median duration of hospitalization, d (range). 6 (3-18). 6 (3-9). 8 (5- ...
Isoproterenol * Mammary Arteries / drug effects* * Mammary Arteries / physiology * Milrinone / pharmacology * Muscle, Smooth, ...
Satake N, Shibata M. Endothelium- and cytochrome P-450-dependent relaxation induced by isoproterenol in rat aortic rings. Eur J ... Endothelium- and cytochrome P-450-dependent relaxation induced by isoproterenol in rat aortic rings. / Satake, N.; Shibata, M. ... Satake, N. ; Shibata, M. / Endothelium- and cytochrome P-450-dependent relaxation induced by isoproterenol in rat aortic rings ... Satake, N & Shibata, M 1997, Endothelium- and cytochrome P-450-dependent relaxation induced by isoproterenol in rat aortic ...
... or during isoproterenol infusion. Alteration in calcium metabolism in the sarcoplasmic reticulum causes accelerated junctional ...
Each step in the pathway can be probed with the appropriate stimulant: isoproterenol for βARs, carbachol for the m2AChR, and ... Either isoproterenol (frontal cortex, occipital cortex) or dopamine (caudate) evoked significant AC stimulation, as did ... as the isoproterenol AC response was 10% above basal values in cortical regions, 50% in the lung, and 300% in the heart, ... 100 μM isoproterenol), or in the caudate, dopamine stimulation (100 μM). Effects mediated through muscarinic cholinergic ...
Isoproterenol alone or in the presence of IBMX had no measurable effect on the ionomycin-induced increase in cytosolic calcium ... Fonteh, A. N., Winkler, J. D., Torphy, T. J., Heravi, J., Undem, B. J., & Chilton, F. H. (1993). Influence of isoproterenol and ... Isoproterenol alone or in the presence of IBMX had no measurable effect on the ionomycin-induced increase in cytosolic calcium ... Isoproterenol alone or in the presence of IBMX had no measurable effect on the ionomycin-induced increase in cytosolic calcium ...
... protein levels in rat hearts following isoproterenol infusion, compared with controls. In conclusion, isoproterenol infusion ... Isoproterenol (5 mg.kg(-1).day(-1)) was infused for 7 days in male Wistar rats (n = 22). In vivo magnetic resonance imaging ( ... Yet, despite widespread use of this model, the effects of isoproterenol on in vivo cardiac function and substrate metabolism ... Fatty acid transporter protein levels were 11-52% lower and triglyceride concentrations were 55% lower in isoproterenol-infused ...
Return to Article Details Cardioprotective Effects of Aqueous Extract of Ripped Musa paradisiaca Peel in Isoproterenol Induced ...
After pretreatment, two doses of isoproterenol (85mg/kg body weight per dose, subcutaneously) were injected to rats at an ... Twenty-four hours after the last dose of isoproterenol, all rats were sacrificed via cervical dislocation. In comparison with ... Cardio Protective Effect of the Semi Purified Flavonoids from Musa sapientum against Isoproterenol-induced Myocardial ... purified flavonoids from banana blossoms on the basis of histopathological parameters and biochemical analysis in isoproterenol ...
THE EFFECT OF ISOPROTERENOL ON CARDIAC OUTPUT AND REGIONAL ORGAN BLOOD FLOW IN PRETERM NEWBORN LAMBS Robert K. Crone, M.D.; ... Robert K. Crone, Joseph R. Custer, A. John Erdmann Ill; THE EFFECT OF ISOPROTERENOL ON CARDIAC OUTPUT AND REGIONAL ORGAN BLOOD ...
Isoproterenol and platelet activating factor can induce kinase translocation. Tsu Tshen Chuang;Sallese M.;Ambrosini G.;Parruti ... The high levels of beta ARK expression in human peripheral blood leukocytes together with the ability of isoproterenol and ... The high levels of beta ARK expression in human peripheral blood leukocytes together with the ability of isoproterenol and ... After 20 min of exposure to isoproterenol (10 microM), the cytosolic beta ARK activity decreased to 61% of control, while ...
(±)-Propranolol hydrochloride ((±)-1-Isopropylamino-3-(1-naphthyloxy)-2-propanol ); ≥ 99% TLC, powder; Propranolol hydrochloride is easily soluble in ethanol and water; β -adrenoceptor antagonist;
Panic anxiety during bolus isoproterenol infusion. Participants received a 4 μg bolus of isoproterenol administered in a single ... The second entailed assessment of cardiorespiratory interoception during isoproterenol infusion.. We chose isoproterenol for ... 1988) Isoproterenol-induced panic attacks. Biol Psychiatry 24:891-902, doi:10.1016/0006-3223(88)90224-7, pmid:3069135. ... 1988) Lactate- and isoproterenol-induced panic attacks in panic disorder patients and controls. Psychiatry Res 23:153-160, doi: ...
Drug (Epinephrine, Isoproterenol, Dopamine, etc.) * * * * * Diluted Drips - Drug (Epinephrine, Isoproterenol, Milrinone, ...
  • In addition, the ability of the cerebellum to respond to trophic stimulation by a beta-adrenergic agonist, isoproterenol, was attenuated markedly. (duke.edu)
  • In the current study, the β-adrenergic receptor agonist isoproterenol, alone or in combination with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), was used to increase cAMP in neutrophils. (arizona.edu)
  • In human mononuclear leukocytes, beta-AR agonist isoproterenol and platelet-activating factor were able to induce translocation of beta ARK from cytosol to membrane. (unich.it)
  • Participants rated their affective and sensory experiences following bolus infusions of either isoproterenol, a rapidly acting peripheral β-adrenergic agonist akin to adrenaline, or saline. (jneurosci.org)
  • SIGNIFICANCE STATEMENT We found that monozygotic twins with focal bilateral amygdala lesions report panic anxiety in response to intravenous infusions of isoproterenol, a β-adrenergic agonist similar to adrenaline. (jneurosci.org)
  • Myocardial injury was induced in tamoxifen-treated Cre-positive p38α KO mice or control littermates via chronic infusion of the β-adrenergic receptor agonist isoproterenol. (whiterose.ac.uk)
  • These junctional tachycardias are most often observed in the setting of digitalis toxicity, recent cardiac surgery, acute myocardial infarction, or isoproterenol infusion. (medscape.com)
  • This occasionally is observed in digitalis toxicity, following cardiac surgery (typically valve replacement), during acute myocardial infarction, or during isoproterenol infusion. (medscape.com)
  • In vivo magnetic resonance imaging (MRI) showed that left ventricular mass increased by 37% and end-diastolic and systolic volumes increased by 33% and 73%, respectively, following isoproterenol infusion. (ox.ac.uk)
  • Myocardial palmitate oxidation rates were 25% lower, and citrate synthase and medium chain acyl-coenzyme A dehydrogenase activities were reduced by 25% and 29%, respectively, following isoproterenol infusion. (ox.ac.uk)
  • Basal glycolysis and glycogen concentration were not changed, yet insulin stimulated glycolysis was decreased by 32%, accompanied by 33% lower insulin stimulated glucose transporter, GLUT4, protein levels in rat hearts following isoproterenol infusion, compared with controls. (ox.ac.uk)
  • In conclusion, isoproterenol infusion impaired in vivo cardiac function, induced hypertrophy, and decreased both fatty acid and glucose metabolism, changes similar in direction and magnitude to those found in the rat heart following moderate severity myocardial infarction. (ox.ac.uk)
  • Isoproterenol infusion in control mice promoted overt cardiac hypertrophy and dysfunction (reduced ejection fraction, increased end systolic volume, increased cardiac weight index, increased cardiomyocyte area, increased fibrosis, and up-regulation of myocyte fetal genes and hypertrophy-associated microRNAs). (whiterose.ac.uk)
  • Isoproterenol infusion can be used to shorten AV conduction time. (medscape.com)
  • Study of the therapeutic and cardioprotective effects of herbal extracts on isoproterenol-induced myocardial necrosis in rats. (fapesp.br)
  • We will study the myocardium of rats,using a classical model of catecholamine induced-injury, isoproterenol (a synthetic catecholamine). (fapesp.br)
  • Isoproterenol (5 mg.kg(-1).day(-1)) was infused for 7 days in male Wistar rats (n = 22). (ox.ac.uk)
  • This study was designed to evaluate the cardio protective effect of the semi-purified flavonoids from banana blossoms on the basis of histopathological parameters and biochemical analysis in isoproterenol induced myocardial infarction in rats. (ajphs.com)
  • After pretreatment, two doses of isoproterenol (85mg/kg body weight per dose, subcutaneously) were injected to rats at an interval of 24 hr for two days (20th and 21st day) to induce myocardial infarction. (ajphs.com)
  • Twenty-four hours after the last dose of isoproterenol, all rats were sacrificed via cervical dislocation. (ajphs.com)
  • At 50mg/kg, the semi-purified flavonoids extract exhibited cardio protection comparable to that of Aspirin hence indicating that the semi-purified flavonoids from banana blossom has a cardioprotectiveeffect against isoproterenol-induced myocardial infarction in rats. (ajphs.com)
  • A cardiac fibrosis model was established in Sprague-Dawley rats through a subcutaneous injection of isoproterenol (ISO, 5 mg/kg/d). (dovepress.com)
  • Study protocol for the data shown in the table: overnight fasted ob/ob mice, Sprague Dawley rats, high fat fed hamsters, and isoproterenol stimulated hamsters were treated orally with either vehicle or NNC0076-0079. (novonordisk.com)
  • The effects of prenatal exposure to ethylene - glycol -monomethyl-ether (109864) (EGME) on heart function in neonatal rats were examined by measuring basal heart ornithine-decarboxylase (ODC) activity and ODC activity after isoproterenol challenge. (cdc.gov)
  • Chronic isoproterenol administration produces a rapid, highly reproducible rodent model of cardiac hypertrophy. (ox.ac.uk)
  • Ablation of p21-activated kinase-1 in mice promotes isoproterenol-induced cardiac hypertrophy in association with activation of Erk1/2 and inhibition of protein phosphatase 2A. (ox.ac.uk)
  • The high levels of beta ARK expression in human peripheral blood leukocytes together with the ability of isoproterenol and platelet-activating factor to induce beta ARK translocation, suggest a role for beta ARK in modulating some receptor-mediated immune functions. (unich.it)
  • Scholars@Duke publication: Effects of neonatal treatment with 6-aminonicotinamide on basal and isoproterenol-stimulated ornithine decarboxylase activity in cerebellum of the development rat. (duke.edu)
  • Exposure on days 7-13 of gestation caused significant decreases in ODC activity for both the basal and the isoproterenol challenged groups. (cdc.gov)
  • Isoproterenol induces in vivo functional and metabolic abnormalities: similar to those found in the infarcted rat heart. (ox.ac.uk)
  • Based upon previous mechanistic interpretations of force transients, and on an analysis developed here to relate crossbridge events to the frequency-dependence of stiffness, we argue that our observations provide evidence that isoproterenol induces an acceleration of crossbridge cycling rate. (njit.edu)
  • Aumento del efecto arritmogénico de isoproterenol. (prvademecum.com)
  • Efecto del isoproterenol sobre la liberación de histamina en mastocitos de pulmón de rata. (bvsalud.org)
  • Age-dependence of isoproterenol-induced dna synthesis in submandibular glands of balb/c mice. (jax.org)
  • Isoproterenol (ISO) (150 mg/kg/day, i.p for 2 consecutive days) was administered to mice to cause myocardial necrosis. (biomedcentral.com)
  • Phlorizin (400 mg/kg/day i.p twice daily for 2 days) and Ritonavir (10 mg/kg/day i.p twice daily for 2 days) were administered in two different groups of mice before isoproterenol administration. (biomedcentral.com)
  • Fibroblast-specific p38α KO mice exhibited marked protection against myocardial injury, with isoproterenol-induced alterations in cardiac function, histology, and molecular markers all being attenuated. (whiterose.ac.uk)
  • We determined the effects of ablation of the Pak-1 gene on the response of the myocardium to chronic stress of isoproterenol (ISO) administration. (ox.ac.uk)
  • Cardiovascular effects such as arrhythmias, angina pectoris, or increased BP occur more commonly with isoproterenol compared to other bronchodilators because isoproterenol stimulates beta-1 receptors of the heart as well as beta-2 receptors on the lungs. (mhmedical.com)
  • Yet, despite widespread use of this model, the effects of isoproterenol on in vivo cardiac function and substrate metabolism are unknown. (ox.ac.uk)
  • In these hearts, we will evaluate two different mechanisms of action of isoproterenol: action on beta1 and beta2 adrenergic receptors and receptor kinase GRK-2 and oxidative stress production. (fapesp.br)
  • In the present study, we evaluated the role of Ritonavir in isoproterenol-induced myocardial necrosis in vivo and compared the effect with Phlorizin, a nonslective SGLTs inhibitor. (biomedcentral.com)
  • The incorporation of [ 3 H]acetate into PAF and the synthesis of leukotrienes in response to ionophore A23187 were significantly inhibited by 10 μM isoproterenol. (arizona.edu)
  • Treatment of neutrophils with isoproterenol and IBMX significantly reduced the production of lyso PAF and PAF from 1-alkyl- 2-arachidonoyl sn-glycero-3-phosphocholine. (arizona.edu)
  • The response to isoproterenol was not significantly altered by exposure to EGME. (cdc.gov)
  • The present study aimed to investigate the biomolecular mechanisms underlying cardioprotective effects of diallyl trisulfide (DATS) as well as captopril (CAP) in isoproterenol (ISO) induced AMI focusing on autophagy & PI3K/Akt signaling. (springeropen.com)
  • If symptoms do not occur, a drug (eg, isoproterenol ) may be given to induce them. (msdmanuals.com)
  • Isoproterenol has been reported to cause insulin resistance leading to diabetic ketoacidosis. (wikipedia.org)
  • Fatty acid transporter protein levels were 11-52% lower and triglyceride concentrations were 55% lower in isoproterenol-infused rat hearts. (ox.ac.uk)
  • In standard animal or human pharmacological tests, beta-adrenoreceptor blocking activity of atenolol tablets have been demonstrated by: (1) reduction in resting and exercise heart rate and cardiac output, (2) reduction of systolic and diastolic blood pressure at rest and on exercise, (3) inhibition of isoproterenol induced tachycardia, and (4) reduction in reflex orthostatic tachycardia. (nih.gov)
  • Isoprenaline, or isoproterenol, is a medication used for the treatment of bradycardia (slow heart rate), heart block, and rarely for asthma. (wikipedia.org)
  • To better understand the mechanism involved in the inhibition of PAF formation, the major biosynthetic steps were examined in the presence and absence of a maximally effective concentration of isoproterenol and IBMX. (arizona.edu)
  • Isoproterenol alone or in the presence of IBMX had no measurable effect on the ionomycin-induced increase in cytosolic calcium concentration, as assessed by fura-2 fluorescence. (arizona.edu)
  • To determine whether catecholamines produce alterations in myocardialmyosin-actin cycling kinetics, we investigated the effects of isoproterenol upon mechanical characteristics of constantly activated heart muscle thought to reflect crossbridge behavior. (njit.edu)
  • Isoproterenol has chronotropic as well as inotropic effects, which result in an increase in cardiac output. (medscape.com)
  • Additional functional disturbances were not noted, even under isoproterenol challenge. (cdc.gov)
  • In vitro study with heart homogenate confirmed no antioxidant effect of ritonavir and phlorizin in the absence and presence of isoproterenol. (biomedcentral.com)
  • Effect of isoproterenol on the liberation of histamine from rat lung mast cells]. (bvsalud.org)
  • Treating intact neutrophils with a combination of isoproterenol and IBMX did not inhibit acetyl-transferase activity when assayed in a subsequent broken cell preparation. (arizona.edu)
  • ODC activity was stimulated in all isoproterenol groups at all times. (cdc.gov)
  • Isoproterenol has beta1- and beta2-adrenergic receptor activity. (medscape.com)
  • In the present study, we inhibited SGLTs and GLUTs transporters in heart by using pharmacological inhibitors, phlorizin (nonselective SGLT blocker) and ritonavir (nonselective GLUTs blocker) respectively, and evaluated the relative importance of these transporters during myocardial necrosis induced by isoproterenol. (biomedcentral.com)
  • Emergency Central , emergency.unboundmedicine.com/emergency/view/Davis-Drug-Guide/51419/all/isoproterenol. (unboundmedicine.com)
  • Isoproterenol infusions induced anxiety in both patients, and full-blown panic in one (patient B.G.). Although both patients demonstrated signs of diminished awareness for cardiac sensation, patient A.M., who did not panic, reported a complete lack of awareness for dyspnea, suggestive of impaired respiratory interoception. (jneurosci.org)
  • However, in patients with severe bradycardia or those with the possibility of progression to higher-degree AV block, medications (eg, atropine, isoproterenol) can be used in anticipation of insertion of a cardiac pacemaker. (medscape.com)
  • Isoproterenol should not be used in patients with hypertrophic cardiomyopathy or severe coronary artery disease. (msdmanuals.com)