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.
Cation-transporting proteins that utilize the energy of ATP hydrolysis for the transport of CALCIUM. They differ from CALCIUM CHANNELS which allow calcium to pass through a membrane without the use of energy.
Calcium-transporting ATPases that catalyze the active transport of CALCIUM into the SARCOPLASMIC RETICULUM vesicles from the CYTOPLASM. They are primarily found in MUSCLE CELLS and play a role in the relaxation of MUSCLES.
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 system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)
A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.
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 methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.
Acidic protein found in SARCOPLASMIC RETICULUM that binds calcium to the extent of 700-900 nmoles/mg. It plays the role of sequestering calcium transported to the interior of the intracellular vesicle.
A methylpyrrole-carboxylate from RYANIA that disrupts the RYANODINE RECEPTOR CALCIUM RELEASE CHANNEL to modify CALCIUM release from SARCOPLASMIC RETICULUM resulting in alteration of MUSCLE CONTRACTION. It was previously used in INSECTICIDES. It is used experimentally in conjunction with THAPSIGARGIN and other inhibitors of CALCIUM ATPASE uptake of calcium into SARCOPLASMIC RETICULUM.
Contractile tissue that produces movement in animals.
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.
Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.
Contractile activity of the MYOCARDIUM.
Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
An inorganic dye used in microscopy for differential staining and as a diagnostic reagent. In research this compound is used to study changes in cytoplasmic concentrations of calcium. Ruthenium red inhibits calcium transport through membrane channels.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
The rate dynamics in chemical or physical systems.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
An electrogenic ion exchange protein that maintains a steady level of calcium by removing an amount of calcium equal to that which enters the cells. It is widely distributed in most excitable membranes, including the brain and heart.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
A sesquiterpene lactone found in roots of THAPSIA. It inhibits CA(2+)-TRANSPORTING ATPASE mediated uptake of CALCIUM into SARCOPLASMIC RETICULUM.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
A process fundamental to muscle physiology whereby an electrical stimulus or action potential triggers a myocyte to depolarize and contract. This mechanical muscle contraction response is regulated by entry of calcium ions into the cell.
A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.
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 excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
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.
Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
A potent local anesthetic of the ester type used for surface and spinal anesthesia.
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.
A local anesthetic of the ester type that has a slow onset and a short duration of action. It is mainly used for infiltration anesthesia, peripheral nerve block, and spinal block. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1016).
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .
Skeletal muscle relaxant that acts by interfering with excitation-contraction coupling in the muscle fiber. It is used in spasticity and other neuromuscular abnormalities. Although the mechanism of action is probably not central, dantrolene is usually grouped with the central muscle relaxants.
Derivatives of OXALIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are derived from the ethanedioic acid structure.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
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)
The hollow, muscular organ that maintains the circulation of the blood.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Rapid and excessive rise of temperature accompanied by muscular rigidity following general anesthesia.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
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).
Various physiological or molecular disturbances that impair ENDOPLASMIC RETICULUM function. It triggers many responses, including UNFOLDED PROTEIN RESPONSE, which may lead to APOPTOSIS; and AUTOPHAGY.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
A metallic element with the atomic symbol V, atomic number 23, and atomic weight 50.94. It is used in the manufacture of vanadium steel. Prolonged exposure can lead to chronic intoxication caused by absorption usually via the lungs.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
5,5'-Nitrilodibarbituric acid ammonium derivative. Used as an indicator for complexometric titrations.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.
Unstable isotopes of calcium that decay or disintegrate emitting radiation. Ca atoms with atomic weights 39, 41, 45, 47, 49, and 50 are radioactive calcium isotopes.
Compounds with three aromatic rings in linear arrangement with an OXYGEN in the center ring.
Benzopyrroles with the nitrogen at the number one carbon adjacent to the benzyl portion, in contrast to ISOINDOLES which have the nitrogen away from the six-membered ring.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A type of endoplasmic reticulum (ER) where polyribosomes are present on the cytoplasmic surfaces of the ER membranes. This form of ER is prominent in cells specialized for protein secretion and its principal function is to segregate proteins destined for export or intracellular utilization.
A class of organic compounds that contains a naphthalene moiety linked to a sulfonic acid salt or ester.
Oxyvanadium ions in various states of oxidation. They act primarily as ion transport inhibitors due to their inhibition of Na(+)-, K(+)-, and Ca(+)-ATPase transport systems. They also have insulin-like action, positive inotropic action on cardiac ventricular muscle, and other metabolic effects.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.
Cationic ionophore antibiotic obtained from Streptomyces lasaliensis that, among other effects, dissociates the calcium fluxes in muscle fibers. It is used as a coccidiostat, especially in poultry.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.
Fluorescent probe capable of being conjugated to tissue and proteins. It is used as a label in fluorescent antibody staining procedures as well as protein- and amino acid-binding techniques.
Inorganic salts of phosphoric acid.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)
Elements of limited time intervals, contributing to particular results or situations.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
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.
Measurement of the intensity and quality of fluorescence.
A photoprotein isolated from the bioluminescent jellyfish Aequorea. It emits visible light by an intramolecular reaction when a trace amount of calcium ion is added. The light-emitting moiety in the bioluminescence reaction is believed to be 2-amino-3-benzyl-5-(p-hydroxyphenyl)pyrazine (AF-350).
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A highly variable species of the family Ranidae in Canada, the United States and Central America. It is the most widely used Anuran in biomedical research.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
The hemodynamic and electrophysiological action of the HEART VENTRICLES.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
An element of the alkaline earth family of metals. It has the atomic symbol Sr, atomic number 38, and atomic weight 87.62.
Use of electric potential or currents to elicit biological responses.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
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.
Intracellular receptors that bind to INOSITOL 1,4,5-TRISPHOSPHATE and play an important role in its intracellular signaling. Inositol 1,4,5-trisphosphate receptors are calcium channels that release CALCIUM in response to increased levels of inositol 1,4,5-trisphosphate in the CYTOPLASM.
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 light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
A family of immunophilin proteins that bind to the immunosuppressive drugs TACROLIMUS (also known as FK506) and SIROLIMUS. EC 5.2.1.-
Lanthanum. The prototypical element in the rare earth family of metals. It has the atomic symbol La, atomic number 57, and atomic weight 138.91. Lanthanide ion is used in experimental biology as a calcium antagonist; lanthanum oxide improves the optical properties of glass.
A type of glycoside widely distributed in plants. Each consists of a sapogenin as the aglycone moiety, and a sugar. The sapogenin may be a steroid or a triterpene and the sugar may be glucose, galactose, a pentose, or a methylpentose.
A type of endoplasmic reticulum lacking associated ribosomes on the membrane surface. It exhibits a wide range of specialized metabolic functions including supplying enzymes for steroid synthesis, detoxification, and glycogen breakdown. In muscle cells, smooth endoplasmic reticulum is called SARCOPLASMIC RETICULUM.
A multifunctional calcium-calmodulin-dependent protein kinase subtype that occurs as an oligomeric protein comprised of twelve subunits. It differs from other enzyme subtypes in that it lacks a phosphorylatable activation domain that can respond to CALCIUM-CALMODULIN-DEPENDENT PROTEIN KINASE KINASE.
A class of compounds composed of repeating 5-carbon units of HEMITERPENES.
Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
The process of cleaving a chemical compound by the addition of a molecule of water.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
A multifunctional protein that is found primarily within membrane-bound organelles. In the ENDOPLASMIC RETICULUM it binds to specific N-linked oligosaccharides found on newly-synthesized proteins and functions as a MOLECULAR CHAPERONE that may play a role in PROTEIN FOLDING or retention and degradation of misfolded proteins. In addition calreticulin is a major storage form for CALCIUM and functions as a calcium-signaling molecule that can regulate intracellular calcium HOMEOSTASIS.
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Agents that increase calcium influx into calcium channels of excitable tissues. This causes vasoconstriction in VASCULAR SMOOTH MUSCLE and/or CARDIAC MUSCLE cells as well as stimulation of insulin release from pancreatic islets. Therefore, tissue-selective calcium agonists have the potential to combat cardiac failure and endocrinological disorders. They have been used primarily in experimental studies in cell and tissue culture.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
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 fluorescent calcium chelating agent which is used to study intracellular calcium in tissues.
A 12-KDa tacrolimus binding protein that is found associated with and may modulate the function of calcium release channels. It is a peptidyl-prolyl cis/trans isomerase which is inhibited by both tacrolimus (commonly called FK506) and SIROLIMUS.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
The ability of a substrate to allow the passage of ELECTRONS.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.
A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.
The family of true frogs of the order Anura. The family occurs worldwide except in Antarctica.
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 heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.
Drugs that selectively bind to and activate beta-adrenergic receptors.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.
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.
5'-Adenylic acid, monoanhydride with imidodiphosphoric acid. An analog of ATP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It is a potent competitive inhibitor of soluble and membrane-bound mitochondrial ATPase and also inhibits ATP-dependent reactions of oxidative phosphorylation.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
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 heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.
Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.
A salt used to replenish calcium levels, as an acid-producing diuretic, and as an antidote for magnesium poisoning.
A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC
Organic nitrogenous bases. Many alkaloids of medical importance occur in the animal and vegetable kingdoms, and some have been synthesized. (Grant & Hackh's Chemical Dictionary, 5th ed)
Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.
The chambers of the heart, to which the BLOOD returns from the circulation.
A phenol obtained from thyme oil or other volatile oils used as a stabilizer in pharmaceutical preparations, and as an antiseptic (antibacterial or antifungal) agent. It was formerly used as a vermifuge.
A nonfluorescent reagent for the detection of primary amines, peptides and proteins. The reaction products are highly fluorescent.
A silver salt with powerful germicidal activity. It has been used topically to prevent OPHTHALMIA NEONATORUM.
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)
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A species of the true toads, Bufonidae, becoming fairly common in the southern United States and almost pantropical. The secretions from the skin glands of this species are very toxic to animals.
Semidomesticated variety of European polecat much used for hunting RODENTS and/or RABBITS and as a laboratory animal. It is in the subfamily Mustelinae, family MUSTELIDAE.
Organic derivatives of thiocyanic acid which contain the general formula R-SCN.
Compounds containing the -SH radical.
An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.
A group of elements that include SCANDIUM; YTTRIUM; and the LANTHANOID SERIES ELEMENTS. Historically, the rare earth metals got their name from the fact that they were never found in their pure elemental form, but as an oxide. In addition they were very difficult to purify. They are not truly rare and comprise about 25% of the metals in the earth's crust.
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology.
The sum of the weight of all the atoms in a molecule.
Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.
An anionic compound that is used as a reagent for determination of potassium, ammonium, rubidium, and cesium ions. It also uncouples oxidative phosphorylation and forms complexes with biological materials, and is used in biological assays.
Carbon-containing phosphoric acid derivatives. Included under this heading are compounds that have CARBON atoms bound to one or more OXYGEN atoms of the P(=O)(O)3 structure. Note that several specific classes of endogenous phosphorus-containing compounds such as NUCLEOTIDES; PHOSPHOLIPIDS; and PHOSPHOPROTEINS are listed elsewhere.
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.
A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.
The processes whereby the internal environment of an organism tends to remain balanced and stable.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.
An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.
A strong dicarboxylic acid occurring in many plants and vegetables. It is produced in the body by metabolism of glyoxylic acid or ascorbic acid. It is not metabolized but excreted in the urine. It is used as an analytical reagent and general reducing agent.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.
Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.
A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.
Transport proteins that carry specific substances in the blood or across cell membranes.
Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin.
A heterogeneous group of drugs used to produce muscle relaxation, excepting the neuromuscular blocking agents. They have their primary clinical and therapeutic uses in the treatment of muscle spasm and immobility associated with strains, sprains, and injuries of the back and, to a lesser degree, injuries to the neck. They have been used also for the treatment of a variety of clinical conditions that have in common only the presence of skeletal muscle hyperactivity, for example, the muscle spasms that can occur in MULTIPLE SCLEROSIS. (From Smith and Reynard, Textbook of Pharmacology, 1991, p358)
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
A phenothiazine with actions similar to CHLORPROMAZINE. It is used as an antipsychotic and an antiemetic.
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).
Established cell cultures that have the potential to propagate indefinitely.
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
The nonstriated involuntary muscle tissue of blood vessels.
The second stomach of ruminants. It lies almost in the midline in the front of the abdomen, in contact with the liver and diaphragm and communicates freely with the RUMEN via the ruminoreticular orifice. The lining of the reticulum is raised into folds forming a honeycomb pattern over the surface. (From Concise Veterinary Dictionary, 1988)
The mitochondria of the myocardium.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Magnesium chloride. An inorganic compound consisting of one magnesium and two chloride ions. The compound is used in medicine as a source of magnesium ions, which are essential for many cellular activities. It has also been used as a cathartic and in alloys.
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.
Terbium. An element of the rare earth family of metals. It has the atomic symbol Tb, atomic number 65, and atomic weight 158.92.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.
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.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Inorganic or organic compounds that contain boron as an integral part of the molecule.
A family of spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one derivatives. These are used as dyes, as indicators for various metals, and as fluorescent labels in immunoassays.
The fluid inside CELLS.
The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.
A sulfhydryl reagent that is widely used in experimental biochemical studies.
The 5-beta-reduced isomer of ANDROSTERONE. Etiocholanolone is a major metabolite of TESTOSTERONE and ANDROSTENEDIONE in many mammalian species including humans. It is excreted in the URINE.
A cellular response to environmental insults that cause disruptions in PROTEIN FOLDING and/or accumulation of defectively folded protein in the ENDOPLASMIC RETICULUM. It consists of a group of regulatory cascades that are triggered as a response to altered levels of calcium and/or the redox state of the endoplasmic reticulum. Persistent activation of the unfolded protein response leads to the induction of APOPTOSIS.
Methods of preparing tissue for examination and study of the origin, structure, function, or pathology.
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 novel interaction mechanism accounting for different acylphosphatase effects on cardiac and fast twitch skeletal muscle sarcoplasmic reticulum calcium pumps. (1/4498)

In cardiac and skeletal muscle Ca2+ translocation from cytoplasm into sarcoplasmic reticulum (SR) is accomplished by different Ca2+-ATPases whose functioning involves the formation and decomposition of an acylphosphorylated phosphoenzyme intermediate (EP). In this study we found that acylphosphatase, an enzyme well represented in muscular tissues and which actively hydrolyzes EP, had different effects on heart (SERCA2a) and fast twitch skeletal muscle SR Ca2+-ATPase (SERCA1). With physiological acylphosphatase concentrations SERCA2a exhibited a parallel increase in the rates of both ATP hydrolysis and Ca2+ transport; in contrast, SERCA1 appeared to be uncoupled since the stimulation of ATP hydrolysis matched an inhibition of Ca2+ pump. These different effects probably depend on phospholamban, which is associated with SERCA2a but not SERCA1. Consistent with this view, the present study suggests that acylphosphatase-induced stimulation of SERCA2a, in addition to an enhanced EP hydrolysis, may be due to a displacement of phospholamban, thus to a removal of its inhibitory effect.  (+info)

Expression of skeletal muscle sarcoplasmic reticulum calcium-ATPase is reduced in rats with postinfarction heart failure. (2/4498)

OBJECTIVE: To determine whether heart failure in rats is associated with altered expression of the skeletal muscle sarcoplasmic reticulum Ca2+-ATPase (SERCA). METHODS: SERCA protein and mRNA were examined in the soleus muscles of eight female rats with heart failure induced by coronary artery ligation, six weeks after the procedure (mean (SEM) left ventricular end diastolic pressure 20.4 (2.2) mm Hg) and in six sham operated controls by western and northern analyses, respectively. RESULTS: SERCA-2a isoform protein was reduced by 16% (112 000 (4000) v 134 000 (2000) arbitrary units, p < 0.001), and SERCA-2a messenger RNA was reduced by 59% (0.24 (0. 06) v 0.58 (0.02) arbitrary units, p < 0.001). Although rats with heart failure had smaller muscles (0.54 mg/g v 0.66 mg/g body weight), no difference in locomotor activity was observed. CONCLUSIONS: These results may explain the previously documented abnormalities in calcium handling in skeletal muscle from animals with the same model of congestive heart failure, and could be responsible for the accelerated muscle fatigue characteristic of patients with heart failure.  (+info)

Ca-releasing action of beta, gamma-methylene adenosine triphosphate on fragmented sarcoplasmic reticulum. (3/4498)

beta,gamma-Methylene adenosine triphosphate (AMPOPCP) has two effects on fragmented sarcoplasmic reticulum (FSR), i.e., inhibition of the rate of Ca uptake and the induction of Ca release from FSR filled with Ca. The Ca release brought about by AMPOPCP has many features in common with the mechanism of Ca-induced Ca release: i) it is inhibited by 10 mM procaine; ii) the amount of Ca release increases with increase in the extent of saturation of FSR with Ca; iii) increase of the Ca concentration in the extent of saturation of FSR with Ca; iii) increase of the Ca concentration in the medium facilitates the release of Ca. However, no facilitation of Ca release upon decrease of Mg concentration in the medium is observable. AMPOPCP and caffeine potentiate each other remarkably in their Ca-releasing action, irrespective of the kind of substrate. From the mode of action of AMPOPCP on the rate of Ca uptake, the amount of phosphorylated intermediate (EP), and the effect on Sr release, it is suggested that the state of the FSR-ATP complex is crucial for Ca-induced Ca release.  (+info)

Mutations of Arg198 in sarcoplasmic reticulum Ca2+-ATPase cause inhibition of hydrolysis of the phosphoenzyme intermediate formed from inorganic phosphate. (4/4498)

Arg198 of sarcoplasmic reticulum Ca2+-ATPase was substituted with lysine, glutamine, glutamic acid, alanine, and isoleucine by site-directed mutagenesis. Kinetic analysis was performed with microsomal membranes isolated from COS-1 cells which were transfected with the mutated cDNAs. The rate of dephosphorylation of the ADP-insensitive phosphoenzyme was determined by first phosphorylating the Ca2+-ATPase with 32Pi and then diluting the sample with non-radioactive Pi. This rate was reduced substantially in the mutant R198Q, more strongly in the mutants R198A and R1981, and most strongly in the mutant R198E, but to a much lesser extent in R198K. The reduction in the rate of dephosphorylation was consistent with the observed decrease in the turnover rate of the Ca2+-ATPase accompanied by the steady-state accumulation of the ADP-insensitive phosphoenzyme formed from ATP. These results indicate that the positive charge and high hydrophilicity of Arg198 are critical for rapid hydrolysis of the ADP-insensitive phosphoenzyme.  (+info)

A repetitive mode of activation of discrete Ca2+ release events (Ca2+ sparks) in frog skeletal muscle fibres. (5/4498)

1. Ca2+ release events (Ca2+ 'sparks'), which are believed to arise from the opening of a sarcoplasmic reticulum (SR) Ca2+ release channel or a small cluster of such channels that act as a release unit, have been measured in single, frog (Rana pipiens) skeletal muscle fibres. 2. Under conditions of extremely low rates of occurrence of Ca2+ sparks we observed, within individual identified triads, repetitive Ca2+ release events which occurred at a frequency more than 100-fold greater than the prevailing average event rate. Repetitive sparks were recorded during voltage-clamp test depolarizations after a brief (0.3-2 s) repriming interval in fibres held at 0 mV and in chronically depolarized, 'notched' fibres. 3. These repetitive events are likely to arise from the re-opening of the same SR Ca2+ release channel or release unit operating in a repetitive gating mode ('rep-mode'), rather than from the random activation of multiple, independent channels or release units within a triad. A train of rep-mode events thus represents a series of Ca2+ sparks arising from a single location within the fibre. Rep-mode events are activated among different triads in a random manner after brief repriming. The frequency of repetitive events among all identified events during voltage-clamp depolarization to 0 mV after brief repriming was 3.9 +/- 1.3 %. The occurrence of repetitive events was not related to exposure of the fibre to laser illumination. 4. The events observed within a rep-mode train exhibited a relatively uniform amplitude. Analysis of intervals between identified events in triads exhibiting rep-mode trains indicated similar variations of fluorescence as in neighbouring, quiescent triads, suggesting there was not a significant number of small, unidentified events at the triads exhibiting rep-mode activity. 5. The distribution of rep-mode interspark intervals exhibited a paucity of events at short intervals, consistent with the need for recovery from inactivation before activation of the next event in a repetitive train. The mean interspark interval of repetitive sparks during voltage-clamp depolarizations was 88 +/- 5 ms, and was independent of membrane potential. 6. The individual Ca2+ sparks within a rep-mode train were similar in average amplitude and spatiotemporal extent to singly occurring sparks, suggesting a common mechanism for termination of the channel opening(s) underlying both types of events. The average properties of the sparks did not vary during a train. The relative amplitude of a spark within a rep-mode was not correlated with its rise time. 7. Repetitive Ca2+ release events represent a mode of gating of SR Ca2+ release channels which may be significant during long depolarizations and which may be influenced by the biochemical state of the SR ryanodine receptor Ca2+ release channels.  (+info)

Local control models of cardiac excitation-contraction coupling. A possible role for allosteric interactions between ryanodine receptors. (6/4498)

In cardiac muscle, release of activator calcium from the sarcoplasmic reticulum occurs by calcium- induced calcium release through ryanodine receptors (RyRs), which are clustered in a dense, regular, two-dimensional lattice array at the diad junction. We simulated numerically the stochastic dynamics of RyRs and L-type sarcolemmal calcium channels interacting via calcium nano-domains in the junctional cleft. Four putative RyR gating schemes based on single-channel measurements in lipid bilayers all failed to give stable excitation-contraction coupling, due either to insufficiently strong inactivation to terminate locally regenerative calcium-induced calcium release or insufficient cooperativity to discriminate against RyR activation by background calcium. If the ryanodine receptor was represented, instead, by a phenomenological four-state gating scheme, with channel opening resulting from simultaneous binding of two Ca2+ ions, and either calcium-dependent or activation-linked inactivation, the simulations gave a good semiquantitative accounting for the macroscopic features of excitation-contraction coupling. It was possible to restore stability to a model based on a bilayer-derived gating scheme, by introducing allosteric interactions between nearest-neighbor RyRs so as to stabilize the inactivated state and produce cooperativity among calcium binding sites on different RyRs. Such allosteric coupling between RyRs may be a function of the foot process and lattice array, explaining their conservation during evolution.  (+info)

Cellular mechanisms of altered contractility in the hypertrophied heart: big hearts, big sparks. (7/4498)

To investigate the cellular mechanisms for altered Ca2+ homeostasis and contractility in cardiac hypertrophy, we measured whole-cell L-type Ca2+ currents (ICa,L), whole-cell Ca2+ transients ([Ca2+]i), and Ca2+ sparks in ventricular cells from 6-month-old spontaneously hypertensive rats (SHRs) and from age- and sex-matched Wistar-Kyoto and Sprague-Dawley control rats. By echocardiography, SHR hearts had cardiac hypertrophy and enhanced contractility (increased fractional shortening) and no signs of heart failure. SHR cells had a voltage-dependent increase in peak [Ca2+]i amplitude (at 0 mV, 1330+/-62 nmol/L [SHRs] versus 836+/-48 nmol/L [controls], P<0.05) that was not associated with changes in ICa,L density or kinetics, resting [Ca2+]i, or Ca2+ content of the sarcoplasmic reticulum (SR). SHR cells had increased time of relaxation. Ca2+ sparks from SHR cells had larger average amplitudes (173+/-192 nmol/L [SHRs] versus 109+/-64 nmol/L [control]; P<0.05), which was due to redistribution of Ca2+ sparks to a larger amplitude population. This change in Ca2+ spark amplitude distribution was not associated with any change in the density of ryanodine receptors, calsequestrin, junctin, triadin 1, Ca2+-ATPase, or phospholamban. Therefore, SHRs with cardiac hypertrophy have increased contractility, [Ca2+]i amplitude, time to relaxation, and average Ca2+ spark amplitude ("big sparks"). Importantly, big sparks occurred without alteration in the trigger for SR Ca2+ release (ICa,L), SR Ca2+ content, or the expression of several SR Ca2+-cycling proteins. Thus, cardiac hypertrophy in SHRs is linked with an alteration in the coupling of Ca2+ entry through L-type Ca2+ channels and the release of Ca2+ from the SR, leading to big sparks and enhanced contractility. Alterations in the microdomain between L-type Ca2+ channels and SR Ca2+ release channels may underlie the changes in Ca2+ homeostasis observed in cardiac hypertrophy. Modulation of SR Ca2+ release may provide a new therapeutic strategy for cardiac hypertrophy and for its progression to heart failure and sudden death.  (+info)

The sarcoplasmic reticulum and the Na+/Ca2+ exchanger both contribute to the Ca2+ transient of failing human ventricular myocytes. (8/4498)

Our objective was to determine the respective roles of the sarcoplasmic reticulum (SR) and the Na+/Ca2+ exchanger in the small, slowly decaying Ca2+ transients of failing human ventricular myocytes. Left ventricular myocytes were isolated from explanted hearts of patients with severe heart failure (n=18). Cytosolic Ca2+, contraction, and action potentials were measured by using indo-1, edge detection, and patch pipettes, respectively. Selective inhibitors of SR Ca2+ transport (thapsigargin) and reverse-mode Na+/Ca2+ exchange activity (No. 7943, Kanebo Ltd) were used to define the respective contribution of these processes to the Ca2+ transient. Ca2+ transients and contractions induced by action potentials (AP transients) at 0.5 Hz exhibited phasic and tonic components. The duration of the tonic component was determined by the action potential duration. Ca2+ transients induced by caffeine (Caf transients) exhibited only a phasic component with a rapid rate of decay that was dependent on extracellular Na+. The SR Ca2+-ATPase inhibitor thapsigargin abolished the phasic component of the AP Ca2+ transient and of the Caf transient but had no significant effect on the tonic component of the AP transient. The Na+/Ca2+ exchange inhibitor No. 7943 eliminated the tonic component of the AP transient and reduced the magnitude of the phasic component. In failing human myocytes, Ca2+ transients and contractions exhibit an SR-related, phasic component and a slow, reverse-mode Na+/Ca2+ exchange-related tonic component. These findings suggest that Ca2+ influx via reverse-mode Na+/Ca2+ exchange during the action potential may contribute to the slow decay of the Ca2+ transient in failing human myocytes.  (+info)

The exact cause of malignant hyperthermia is not fully understood, but it is believed to be related to a genetic predisposition and exposure to certain anesthetic agents. The condition can be triggered by a variety of factors, including the use of certain anesthetics, stimulation of the sympathetic nervous system, and changes in blood sugar levels.

Symptoms of malignant hyperthermia can include:

* Elevated body temperature (usually above 104°F/40°C)
* Muscle rigidity and stiffness
* Heart arrhythmias and palpitations
* Shivering or tremors
* Confusion, agitation, or other neurological symptoms
* Shortness of breath or respiratory failure

If left untreated, malignant hyperthermia can lead to serious complications such as seizures, brain damage, and even death. Treatment typically involves the immediate discontinuation of any triggering anesthetic agents, cooling measures such as ice packs or cold compresses, and medications to help regulate body temperature and reduce muscle rigidity. In severe cases, mechanical ventilation may be necessary to support breathing.

Overall, malignant hyperthermia is a rare but potentially life-threatening condition that requires prompt recognition and treatment to prevent serious complications and improve outcomes.

Medical Term: Cardiomegaly

Definition: An abnormal enlargement of the heart.

Symptoms: Difficulty breathing, shortness of breath, fatigue, swelling of legs and feet, chest pain, and palpitations.

Causes: Hypertension, cardiac valve disease, myocardial infarction (heart attack), congenital heart defects, and other conditions that affect the heart muscle or cardiovascular system.

Diagnosis: Physical examination, electrocardiogram (ECG), chest x-ray, echocardiography, and other diagnostic tests as necessary.

Treatment: Medications such as diuretics, vasodilators, and beta blockers, lifestyle changes such as exercise and diet modifications, surgery or other interventions in severe cases.

Note: Cardiomegaly is a serious medical condition that requires prompt diagnosis and treatment to prevent complications such as heart failure and death. If you suspect you or someone else may have cardiomegaly, seek medical attention immediately.

There are many different types of cardiac arrhythmias, including:

1. Tachycardias: These are fast heart rhythms that can be too fast for the body's needs. Examples include atrial fibrillation and ventricular tachycardia.
2. Bradycardias: These are slow heart rhythms that can cause symptoms like fatigue, dizziness, and fainting. Examples include sinus bradycardia and heart block.
3. Premature beats: These are extra beats that occur before the next regular beat should come in. They can be benign but can also indicate an underlying arrhythmia.
4. Supraventricular arrhythmias: These are arrhythmias that originate above the ventricles, such as atrial fibrillation and paroxysmal atrial tachycardia.
5. Ventricular arrhythmias: These are arrhythmias that originate in the ventricles, such as ventricular tachycardia and ventricular fibrillation.

Cardiac arrhythmias can be diagnosed through a variety of tests including electrocardiograms (ECGs), stress tests, and holter monitors. Treatment options for cardiac arrhythmias vary depending on the type and severity of the condition and may include medications, cardioversion, catheter ablation, or implantable devices like pacemakers or defibrillators.

There are two main types of heart failure:

1. Left-sided heart failure: This occurs when the left ventricle, which is the main pumping chamber of the heart, becomes weakened and is unable to pump blood effectively. This can lead to congestion in the lungs and other organs.
2. Right-sided heart failure: This occurs when the right ventricle, which pumps blood to the lungs, becomes weakened and is unable to pump blood effectively. This can lead to congestion in the body's tissues and organs.

Symptoms of heart failure may include:

* Shortness of breath
* Fatigue
* Swelling in the legs, ankles, and feet
* Swelling in the abdomen
* Weight gain
* Coughing up pink, frothy fluid
* Rapid or irregular heartbeat
* Dizziness or lightheadedness

Treatment for heart failure typically involves a combination of medications and lifestyle changes. Medications may include diuretics to remove excess fluid from the body, ACE inhibitors or beta blockers to reduce blood pressure and improve blood flow, and aldosterone antagonists to reduce the amount of fluid in the body. Lifestyle changes may include a healthy diet, regular exercise, and stress reduction techniques. In severe cases, heart failure may require hospitalization or implantation of a device such as an implantable cardioverter-defibrillator (ICD) or a left ventricular assist device (LVAD).

It is important to note that heart failure is a chronic condition, and it requires ongoing management and monitoring to prevent complications and improve quality of life. With proper treatment and lifestyle changes, many people with heart failure are able to manage their symptoms and lead active lives.

There are several types of cardiomyopathies, each with distinct characteristics and symptoms. Some of the most common forms of cardiomyopathy include:

1. Hypertrophic cardiomyopathy (HCM): This is the most common form of cardiomyopathy and is characterized by an abnormal thickening of the heart muscle, particularly in the left ventricle. HCM can lead to obstruction of the left ventricular outflow tract and can increase the risk of sudden death.
2. Dilated cardiomyopathy: This type of cardiomyopathy is characterized by a decrease in the heart's ability to pump blood effectively, leading to enlargement of the heart and potentially life-threatening complications such as congestive heart failure.
3. Restrictive cardiomyopathy: This type of cardiomyopathy is characterized by stiffness of the heart muscle, which makes it difficult for the heart to fill with blood. This can lead to shortness of breath and fatigue.
4. Left ventricular non-compaction (LVNC): This is a rare type of cardiomyopathy that occurs when the left ventricle does not properly compact, leading to reduced cardiac function and potentially life-threatening complications.
5. Cardiac amyloidosis: This is a condition in which abnormal proteins accumulate in the heart tissue, leading to stiffness and impaired cardiac function.
6. Right ventricular cardiomyopathy (RVCM): This type of cardiomyopathy is characterized by impaired function of the right ventricle, which can lead to complications such as pulmonary hypertension and heart failure.
7. Endocardial fibroelastoma: This is a rare type of cardiomyopathy that occurs when abnormal tissue grows on the inner lining of the heart, leading to reduced cardiac function and potentially life-threatening complications.
8. Cardiac sarcoidosis: This is a condition in which inflammatory cells accumulate in the heart, leading to impaired cardiac function and potentially life-threatening complications.
9. Hypertrophic cardiomyopathy (HCM): This is a condition in which the heart muscle thickens, leading to reduced cardiac function and potentially life-threatening complications such as arrhythmias and sudden death.
10. Hypokinetic left ventricular cardiomyopathy: This type of cardiomyopathy is characterized by decreased contraction of the left ventricle, leading to reduced cardiac function and potentially life-threatening complications such as heart failure.

It's important to note that some of these types of cardiomyopathy are more common in certain populations, such as hypertrophic cardiomyopathy being more common in young athletes. Additionally, some types of cardiomyopathy may have overlapping symptoms or co-occurring conditions, so it's important to work with a healthcare provider for an accurate diagnosis and appropriate treatment.


Cardiac output is typically measured using invasive or non-invasive methods. Invasive methods involve inserting a catheter into the heart to directly measure cardiac output. Non-invasive methods include echocardiography, MRI, and CT scans. These tests can provide an estimate of cardiac output based on the volume of blood being pumped out of the heart and the rate at which it is being pumped.


There are several factors that can contribute to low cardiac output. These include:

1. Heart failure: This occurs when the heart is unable to pump enough blood to meet the body's needs, leading to fatigue and shortness of breath.
2. Anemia: A low red blood cell count can reduce the amount of oxygen being delivered to the body's tissues, leading to fatigue and weakness.
3. Medication side effects: Certain medications, such as beta blockers, can slow down the heart rate and reduce cardiac output.
4. Sepsis: A severe infection can lead to inflammation throughout the body, which can affect the heart's ability to pump blood effectively.
5. Myocardial infarction (heart attack): This occurs when the heart muscle is damaged due to a lack of oxygen, leading to reduced cardiac output.


Low cardiac output can cause a range of symptoms, including:

1. Fatigue and weakness
2. Dizziness and lightheadedness
3. Shortness of breath
4. Pale skin
5. Decreased urine output
6. Confusion and disorientation


The treatment of low cardiac output depends on the underlying cause. Treatment may include:

1. Medications to increase heart rate and contractility
2. Diuretics to reduce fluid buildup in the body
3. Oxygen therapy to increase oxygenation of tissues
4. Mechanical support devices, such as intra-aortic balloon pumps or ventricular assist devices
5. Surgery to repair or replace damaged heart tissue
6. Lifestyle changes, such as a healthy diet and regular exercise, to improve cardiovascular health.


Preventing low cardiac output involves managing any underlying medical conditions, taking medications as directed, and making lifestyle changes to improve cardiovascular health. This may include:

1. Monitoring and controlling blood pressure
2. Managing diabetes and other chronic conditions
3. Avoiding substances that can damage the heart, such as tobacco and excessive alcohol
4. Exercising regularly
5. Eating a healthy diet that is low in saturated fats and cholesterol
6. Maintaining a healthy weight.

1. Muscular dystrophy: A group of genetic disorders characterized by progressive muscle weakness and degeneration.
2. Myopathy: A condition where the muscles become damaged or diseased, leading to muscle weakness and wasting.
3. Fibromyalgia: A chronic condition characterized by widespread pain, fatigue, and muscle stiffness.
4. Rhabdomyolysis: A condition where the muscle tissue is damaged, leading to the release of myoglobin into the bloodstream and potentially causing kidney damage.
5. Polymyositis/dermatomyositis: Inflammatory conditions that affect the muscles and skin.
6. Muscle strain: A common injury caused by overstretching or tearing of muscle fibers.
7. Cervical dystonia: A movement disorder characterized by involuntary contractions of the neck muscles.
8. Myasthenia gravis: An autoimmune disorder that affects the nerve-muscle connection, leading to muscle weakness and fatigue.
9. Oculopharyngeal myopathy: A condition characterized by weakness of the muscles used for swallowing and eye movements.
10. Inclusion body myositis: An inflammatory condition that affects the muscles, leading to progressive muscle weakness and wasting.

These are just a few examples of the many different types of muscular diseases that can affect individuals. Each condition has its unique set of symptoms, causes, and treatment options. It's important for individuals experiencing muscle weakness or wasting to seek medical attention to receive an accurate diagnosis and appropriate care.

Source: Genetic and Rare Diseases Information Center (GARD), the National Institutes of Health (NIH)

1) They share similarities with humans: Many animal species share similar biological and physiological characteristics with humans, making them useful for studying human diseases. For example, mice and rats are often used to study diseases such as diabetes, heart disease, and cancer because they have similar metabolic and cardiovascular systems to humans.

2) They can be genetically manipulated: Animal disease models can be genetically engineered to develop specific diseases or to model human genetic disorders. This allows researchers to study the progression of the disease and test potential treatments in a controlled environment.

3) They can be used to test drugs and therapies: Before new drugs or therapies are tested in humans, they are often first tested in animal models of disease. This allows researchers to assess the safety and efficacy of the treatment before moving on to human clinical trials.

4) They can provide insights into disease mechanisms: Studying disease models in animals can provide valuable insights into the underlying mechanisms of a particular disease. This information can then be used to develop new treatments or improve existing ones.

5) Reduces the need for human testing: Using animal disease models reduces the need for human testing, which can be time-consuming, expensive, and ethically challenging. However, it is important to note that animal models are not perfect substitutes for human subjects, and results obtained from animal studies may not always translate to humans.

6) They can be used to study infectious diseases: Animal disease models can be used to study infectious diseases such as HIV, TB, and malaria. These models allow researchers to understand how the disease is transmitted, how it progresses, and how it responds to treatment.

7) They can be used to study complex diseases: Animal disease models can be used to study complex diseases such as cancer, diabetes, and heart disease. These models allow researchers to understand the underlying mechanisms of the disease and test potential treatments.

8) They are cost-effective: Animal disease models are often less expensive than human clinical trials, making them a cost-effective way to conduct research.

9) They can be used to study drug delivery: Animal disease models can be used to study drug delivery and pharmacokinetics, which is important for developing new drugs and drug delivery systems.

10) They can be used to study aging: Animal disease models can be used to study the aging process and age-related diseases such as Alzheimer's and Parkinson's. This allows researchers to understand how aging contributes to disease and develop potential treatments.

The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth ... The sarcoplasmic reticulum is a network of tubules that extend throughout muscle cells, wrapping around (but not in direct ... The cytosolic side of the pump then closes and the sarcoplasmic reticulum side opens, releasing the Ca2+ into the SR. A protein ... Mechanisms of caffeine activation of single calcium-release channels of sheep cardiac sarcoplasmic reticulum. J Physiol (Lond) ...
... the calcium arrives at the sarcoplasmic reticulum. Within the lumen of the cardiac myocyte, the sarcoplasmic reticulum serves ... Most muscle cells contain a triad, which is a joining of 2 terminal cisternae of the sarcoplasmic reticulum and one t- tubule. ... For example, a leading cause of heart failure can be attributed to the lack of t- tubule and sarcoplasmic reticulum junctions ... The t-tubules and sarcoplasmic reticulum are used in conjunction to receive and direct the calcium ions and cause contraction. ...
... sarcoplasmic reticulum; Golgi apparatus; lysosome; mitochondrion (inner and outer membranes); nucleus (inner and outer ... In eucaryotic cells, new phospholipids are manufactured by enzymes bound to the part of the endoplasmic reticulum membrane that ... Distinct types of membranes also create intracellular organelles: endosome; smooth and rough endoplasmic reticulum; ...
Deamer, D.W.; Baskin, R.J. (1969). "Ultrastructure of sarcoplasmic reticulum preparations". Journal of Cell Biology. 42 (1): ... revealing for the first time particles related to functional ATPase enzymes within the membranes of sarcoplasmic reticulum. ...
Lehnart SE, Schillinger W, Pieske B, Prestle J, Just H, Hasenfuss G (September 1998). "Sarcoplasmic reticulum proteins in heart ... April 2005). "Modulation of sarcoplasmic reticulum function by Na+/K+ pump inhibitors with different toxicity: digoxin and ... January 2007). "Istaroxime, a stimulator of sarcoplasmic reticulum calcium adenosine triphosphatase isoform 2a activity, as a ... September 2008). "Modulation of sarcoplasmic reticulum function by PST2744 [istaroxime; (E,Z)-3-((2-aminoethoxy)imino) ...
... endoplasmic reticulum or sarcoplasmic reticulum). Although CICR was first proposed for skeletal muscle in the 1970s, it is now ... Fabiato A (July 1983). "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum". The American Journal of ... Endo M (January 1977). "Calcium release from the sarcoplasmic reticulum". Physiological Reviews. 57 (1): 71-108. doi:10.1152/ ... relies on sarcolemma depolarization and subsequent Ca2+ entry to trigger Ca2+ release from the sarcoplasmic reticulum. When an ...
This is due to relatively spare sarcoplasmic reticulum. Because of requirements for high force production, myofiber and ... In addition to the reduction in sarcoplasmic reticulum, relatively large myofibril diameters lead to increased diffusion times ... In Cotinus mutabilis, asynchronous muscles are composed of 58.1% myofibril, 36.7% mitochondria, and 1.6% sarcoplasmic reticulum ... sarcoplasmic reticulum. Although synchronous muscle has a higher percentage of myofibril, the cross-sectional area of ...
Proteins of the cardiac junctional sarcoplasmic reticulum membrane". The Journal of Biological Chemistry. 272 (37): 23389-97. ... their functions which involve roles in the calcium storage and release process in the endoplasmic and sarcoplasmic reticulum as ... plasmic reticulum membrane". The Journal of Biological Chemistry. 275 (50): 39555-68. doi:10.1074/jbc.M005473200. PMID 11007777 ...
D. Chadwick (2002). Role of the sarcoplasmic reticulum in smooth muscle. John Wiley and Sons. pp. 259-264. ISBN 0-470-84479-5. ...
Chadwick, D. (2002). Role of the sarcoplasmic reticulum in smooth muscle. John Wiley and Sons. pp. 259-264. ISBN 978-0-470- ...
... concentration in the sarcoplasmic reticulum in cardiac cells maintenance of Ca2+ concentration in the endoplasmic reticulum of ... The sarcoplasmic reticulum release of Ca2+ is inhibited. Other Ca2+ influx channels are inhibited. If the action potential ... The exchanger is usually found in the plasma membranes and the mitochondria and endoplasmic reticulum of excitable cells. The ...
Sarcoplasmic/endoplasmic reticulum calcium ATPase 1 (SERCA1) is an enzyme that in humans is encoded by the ATP2A1 gene. This ... 2001). "Mutations of either or both Cys876 and Cys888 residues of sarcoplasmic reticulum Ca2+ATPase result in a complete loss ... Pieske B, Maier LS, Schmidt-Schweda S (2002). "Sarcoplasmic reticulum Ca2+ load in human heart failure". Basic Res. Cardiol. 97 ... 1996). "Mutations in the gene-encoding SERCA1, the fast-twitch skeletal muscle sarcoplasmic reticulum Ca2+ ATPase, are ...
... , also known as TRDN, is a human gene associated with the release of calcium ions from the sarcoplasmic reticulum ... The luminal (inner compartment of the sarcoplasmic reticulum) section of Triadin has areas of highly charged amino acid ... Proteins of the cardiac junctional sarcoplasmic reticulum membrane". J. Biol. Chem. 272 (37): 23389-97. doi:10.1074/jbc.272.37. ... 2007). "Histidine-rich Ca-binding protein interacts with sarcoplasmic reticulum Ca-ATPase". Am. J. Physiol. Heart Circ. Physiol ...
Each muscle fiber contains sarcolemma, sarcoplasm, and sarcoplasmic reticulum. The functional unit of a muscle fiber is called ... Striated muscle tissue contains T-tubules which enables the release of calcium ions from the sarcoplasmic reticulum. Skeletal ... motor neurons cause skeletal muscle fibers to depolarize and therefore release calcium ions from the sarcoplasmic reticulum. ...
Association with increased sarcoplasmic reticulum Ca2+-ATPase and alpha-myosin heavy chain in rat hearts". The Journal of ... It resides in the sarcoplasmic reticulum (SR) within myocytes. It is a Ca2+ ATPase that transfers Ca2+ from the cytosol of the ... Sarcoplasmic+Reticulum+Calcium-Transporting+ATPases at the US National Library of Medicine Medical Subject Headings (MeSH) ( ... Its major function is to transport calcium from the cytosol into the sarcoplasmic reticulum. SERCA is a P-type ATPase. ...
The calcium is then held within the sarcoplasmic reticulum by a protein called calsequestrin. Fine-tuning of this process can ... Sarcoplasmic reticulum calcium content increases in response to stimulation from catecholamines, explaining why arrhythmias in ... While calcium is generally released from the sarcoplasmic reticulum in response to an action potential, calcium sparks can also ... At the start of each heartbeat, calcium is released from the sarcoplasmic reticulum through specialised channels known as ...
The sarco/endoplasmic reticulum calcium-ATPase (SERCA) actively pumps Ca2+ back into the sarcoplasmic reticulum. As Ca2+ ... Note that the sarcoplasmic reticulum has a large calcium buffering capacity partially due to a calcium-binding protein called ... Termination of cross-bridge cycling can occur when Ca2+ is actively pumped back into the sarcoplasmic reticulum. When Ca2+ is ... The active pumping of Ca2+ ions into the sarcoplasmic reticulum creates a deficiency in the fluid around the myofibrils. This ...
Tada M, Kirchberger MA, Katz AM (1975). "Phosphorylation of a 22,000-dalton component of the cardiac sarcoplasmic reticulum by ... Takenaka H, Adler PN, Katz AM (1982). "Calcium fluxes across the membrane of sarcoplasmic reticulum vesicles". J Biol Chem. 257 ... Katz AM, Repke DI, Dunnett J, Hasselbach W (1977). "Dependence of calcium permeability of sarcoplasmic reticulum vesicles on ... "Reaction mechanism of Ca2+-dependent ATP hydrolysis by skeletal muscle sarcoplasmic reticulum in the absence of added alkali ...
A calcium spark is the microscopic release of calcium (Ca2+) from a store known as the sarcoplasmic reticulum (SR), located ... Fabiato, A (1983). "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum". Am. J. Physiol. 245 (1): C1- ... located on the sarcoplasmic reticulum and activation, by the action potential causes the DHPRs to change shape. In cardiac and ... see sarcoplasmic reticulum for more details). Similarly, a decrease in Ca2+ concentration within the SR has also proven to ...
... is a calcium-binding protein that acts as a calcium buffer within the sarcoplasmic reticulum. The protein helps ... It also helps the sarcoplasmic reticulum store an extraordinarily high amount of calcium ions. Each molecule of calsequestrin ... even though the concentration of calcium in the sarcoplasmic reticulum is much higher than in the cytosol. ... "Crystal structure of calsequestrin from rabbit skeletal muscle sarcoplasmic reticulum". Nat. Struct. Biol. 5 (6): 476-83. doi: ...
He is known for his discovery of the sarcoplasmic reticulum. He studied medicine at the Universities of Pavia and Bologna, ... In March 1902, he provided the first accurate description of the reticular network (sarcoplasmic reticulum) in skeletal muscle ... Vanio Vannini and Umberto Muscatello The sarcoplasmic reticulum: its discovery and rediscovery Nature Reviews Molecular Cell ... In 1961 "Veratti's reticulum" was re-discovered through the use of electron microscopy. Veratti E., 1902. Ricerche sulla fine ...
It is specifically localized to the sarcoplasmic reticulum and nuclear membrane, and is involved in anchoring PKA to the ... A protein that targets A-kinase to the sarcoplasmic reticulum". J Biol Chem. 270 (16): 9327-33. doi:10.1074/jbc.270.16.9327. ... nuclear membrane or sarcoplasmic reticulum. AKAP6 has been shown to interact with Ryanodine receptor 2 and PDE4D3. GRCh38: ...
Another important ion is calcium (Ca2+), which can be found inside the cell in the sarcoplasmic reticulum (SR) where calcium is ... These calcium ions bind to and open more calcium channels (called ryanodine receptors) located on the sarcoplasmic reticulum ... Koivumäki, Jussi T.; Korhonen, Topi; Tavi, Pasi (2011-01-01). "Impact of Sarcoplasmic Reticulum Calcium Release on Calcium ... Calcium is released from the sarcoplasmic reticulum within the cell. This calcium then increases activation of the sodium- ...
The sarcoplasmic reticulum plays a major role in excitation-contraction coupling. The endoplasmic reticulum serves many general ... The sarcoplasmic reticulum (SR), from the Greek σάρξ sarx ("flesh"), is smooth ER found in muscle cells. The only structural ... Toyoshima C, Nakasako M, Nomura H, Ogawa H (June 2000). "Crystal structure of the calcium pump of sarcoplasmic reticulum at 2.6 ... After their release from the sarcoplasmic reticulum, calcium ions interact with contractile proteins that utilize ATP to ...
Schulte, LM; Navarro, J; Kandarian, SC (May 1993). "Regulation of sarcoplasmic reticulum calcium pump gene expression by ... that the unloading state of spaceflight and of HS also increases the expression of fast type II sarcoplasmic reticulum (SR) ...
... that regulates several sarcoplasmic reticulum Ca2+-ATPases by reducing the accumulation of Ca2+ in the sarcoplasmic reticulum ... Sarcoplasmic reticulum Ca2+-ATPases are transmembrane proteins that catalyze the ATP-dependent transport of Ca2+ from the ... Sarcolipin is an important mediator of muscle based non shivering thermogenesis (NST). It causes the sarcoplasmic reticulum ... "Sarcolipin uncouples hydrolysis of ATP from accumulation of Ca2+ by the Ca2+-ATPase of skeletal-muscle sarcoplasmic reticulum ...
This increases the re-uptake of calcium by the sarcoplasmic reticulum. β-blockers are sympatholytic drugs. Some β-blockers ... Protein kinase A also increases the release of calcium from the sarcoplasmic reticulum, which causes a positive inotropic ...
Sarcoplasmic reticulum histidine-rich calcium-binding protein is a protein that in humans is encoded by the HRC gene. Histidine ... Kim E, Shin DW, Hong CS, Jeong D, Kim DH, Park WJ (Jan 2003). "Increased Ca2+ storage capacity in the sarcoplasmic reticulum by ... Hofmann SL, Topham M, Hsieh CL, Francke U (Apr 1991). "cDNA and genomic cloning of HRC, a human sarcoplasmic reticulum protein ... Hofmann SL, Brown MS, Lee E, Pathak RK, Anderson RG, Goldstein JL (May 1989). "Purification of a sarcoplasmic reticulum protein ...
T-tubules and sarcoplasmic reticulum. He also introduced microtome cutting Keith Porter was born in Yarmouth, Nova Scotia, on ... Porter's research at Harvard concerned the sarcoplasmic reticulum and T system; he conducted this work in collaboration with ... He was also responsible for naming the endoplasmic reticulum, conducting work on the 9 + 2 microtubule structure in the axoneme ...
In the cell, they are located in the sarcoplasmic or endoplasmatic reticulum. SERCA1a is a type IIA pump. The second group of ... Toyoshima C, Nakasako M, Nomura H, Ogawa H (June 2000). "Crystal structure of the calcium pump of sarcoplasmic reticulum at 2.6 ... One report suggests that this sarcoplasmic reticulum (SR) Ca2+ ATPase is homodimeric. Crystal structures have shown that the ... "The dimeric form of Ca2+-ATPase is involved in Ca2+ transport in the sarcoplasmic reticulum". The Biochemical Journal. 414 (3 ...
... sarcoplasmic reticulum. Immediately after muscle contraction, intracellular Ca²⁺ is quickly returned to its normal ... and a calcium pump in sarcoplasmic reticulum, causing the muscle to relax. According to the Blaustein-hypothesis, this carrier ...
"Characterization of endonuclease G and mitochondria-sarcoplasmic reticulum-related proteins during cardiac hypertrophy". Die ...
... rough ER sarcoplasmic reticulum - satellite DNA - scientific notation - SDS-PAGE - second messenger - second messenger system ... endoplasmic reticulum - endothelin receptor - endothelin-1 - energy decomposition cycles - energy level - enhancer - enkephalin ...
... the sarcoplasmic reticulum, as shown by an increase in Ca2+ spark rate upon axial stretch of single cardiac myocytes. Finally, ... sensitivity of troponin for binding Ca2+ increases and there is an increased release of Ca2+ from the sarcoplasmic reticulum. ...
Rembold CM, Kendall JM, Campbell AK (January 1997). "Measurement of changes in sarcoplasmic reticulum [Ca2+] in rat tail artery ... "Monitoring dynamic changes in free Ca2+ concentration in the endoplasmic reticulum of intact cells". EMBO J. 14 (22): 5467-5475 ... "Recombinant apoaequorin acting as a pseudo-luciferase reports micromolar changes in the endoplasmic reticulum free Ca2+ of ...
... modifies the Ryanodine receptor channels RyR1 and RyR2, found in the sarcoplasmic reticulum, to a long-lasting ... Hadrucalcin targets ryanodine receptor channels RyR1 and RyR2, found in the sarcoplasmic reticulum of skeletal muscle cells and ... thus inducing the release of calcium from the sarcoplasmic reticulum. Hadrucalcin (HdCa, alternative spelling: Hadrucalcine) is ... is able to permeate the cell membrane of ventricular myocytes and induce the release of calcium from the sarcoplasmic reticulum ...
... nuclear magnetic resonance and fluorescence depolarization studies of functional reconstituted sarcoplasmic reticulum membrane ...
... and during systole the rise in intracellular calcium from sarcoplasmic reticulum binds to troponin C and induces a ...
Muscular contraction during exercise causes calcium to be released from the sarcoplasmic reticulum (SR), a specialized ER ... "Endoplasmic reticulum stress affects the transport of phosphatidylethanolamine from mitochondria to the endoplasmic reticulum ... Endoplasmic reticulum stress was reported to play a major role in non‐alcoholic fatty liver disease (NAFLD) induction and ... The UPR is activated in response to an accumulation of unfolded or misfolded proteins in the lumen of the endoplasmic reticulum ...
... dystrophy protein kinase phosphorylates phospholamban and regulates calcium uptake in cardiomyocyte sarcoplasmic reticulum". ... The different C termini of DMPK that arise from alternative splicing determine its localization to the endoplasmic reticulum, ...
An activation of smooth muscle cells through caffeine activates ryanodine receptors of the sarcoplasmic reticulum, whereas an ...
The sarcoplasmic and endoplasmic reticulum calcium pumps are closely related in structure and mechanism, and both are inhibited ... In the skeletal muscles the calcium pump in the sarcoplasmic reticulum membrane works in harmony with similar calcium pumps in ... The two kinds of calcium ATPase are: Plasma membrane Ca2+ ATPase (PMCA) Sarcoplasmic reticulum Ca2+ ATPase (SERCA) Plasma ... called sarcoplasmic reticulum (SR). It is a Ca2+ ATPase that transfers Ca2+ from the cytosol of the cell to the lumen of the SR ...
Junctional complexes between the plasma membrane and endoplasmic/sarcoplasmic reticulum are a common feature of all excitable ... the space between the plasma membrane and sarcoplasmic reticulum. These cardiac dyads also known as junctional membrane ... by approximating L-type calcium channels on the plasma membrane and ryanodine receptor type 2 on the sarcoplasmic reticulum. ... of junctional complexes and is composed of a C-terminal hydrophobic segment spanning the endoplasmic/sarcoplasmic reticulum ...
... a disorganized depolarization of the motor end-plate occurs and calcium is released from the sarcoplasmic reticulum. In normal ... As the calcium is taken up by the sarcoplasmic reticulum, the muscle relaxes. This explains muscle flaccidity rather than ...
Sarcoplasmic reticulum CaATPase (SERCA) is an energy-dependent ion pump found the sarcoplasmic reticulum of cardiac myocytes ... Ryanodine receptors are located within the membrane of the sarcoplasmic reticulum and function to release Ca2+ required for ... Impaired ventricular function can be a consequence of decreased sarcoplasmic reticulum Ca2+ cycling and a corresponding decline ... thereby enhancing Ca2+ release from the sarcoplasmic reticulum. It is thought that nitroxyl modifies RyR2 function through its ...
... which signals them to contract through the release of calcium by the sarcoplasmic reticulum. Fatigue (reduced ability to ... Past this point, training effects increase muscular strength through myofibrillar or sarcoplasmic hypertrophy and metabolic ...
... in nearly all cells and the sarcoplasmic reticulum (SR) in muscle cells. The ER is where protein processing and transport ... ATP2A2 encodes the SERCA2 protein, which is a calcium pump localized to the membranes of the endoplasmic reticulum (ER) ...
... homeostasis and increased cytoplasmic calcium concentrations cause increased calcium uptake into the sarcoplasmic reticulum (SR ...
It also suppresses the norepinephrine-induced increase in the sarcoplasmic reticulum (SR) Ca2+ leak and the spontaneous SR Ca2+ ...
In a heart with AF, the increased calcium release from the sarcoplasmic reticulum and increased calcium sensitivity can lead to ...
When phosphorylated (by PKA) - disinhibition of Ca2+-ATPase of SR leads to faster Ca2+ uptake into the sarcoplasmic reticulum, ... In the unphosphorylated state, phospholamban is an inhibitor of cardiac muscle sarcoplasmic reticulum Ca2+-ATPase (SERCA2) ... "The stimulation of calcium transport in cardiac sarcoplasmic reticulum by adenosine 3':5'-monophosphate-dependent protein ... which transports calcium from cytosol into the sarcoplasmic reticulum. ...
... endoplasmic reticulum, smooth MeSH A11.284.430.214.190.875.248.310.800 - sarcoplasmic reticulum MeSH A11.284.430.214.190.875. ... endoplasmic reticulum MeSH A11.284.430.214.190.875.248.300 - endoplasmic reticulum, rough MeSH A11.284.430.214.190.875.248.300. ... endoplasmic reticulum, rough MeSH A11.284.430.214.190.875.811.740.300.610 - nissl bodies MeSH A11.284.430.214.190.875.820 - ...
Active transport moves calcium ions back into the sarcoplasmic reticulum of the muscle fiber. ATP causes the binding between ... This depolarizes the muscle fiber membrane, and the impulse travels to the muscle's sarcoplasmic reticulum via the transverse ... Calcium ions are then released from the sarcoplasmic reticulum into the sarcoplasm and subsequently bind to troponin. Troponin ...
sarcoplasmic reticulum. MP. mastoparan. HSR. heavy fraction of sarcoplasmic reticulum. SR Ca2+-pump. sarco/endoplasmic ... Identification of a 97-kDa Mastoparan-Binding Protein Involving in Ca2+ Release from Skeletal Muscle Sarcoplasmic Reticulum. ... Identification of a 97-kDa Mastoparan-Binding Protein Involving in Ca2+ Release from Skeletal Muscle Sarcoplasmic Reticulum. ... Identification of a 97-kDa Mastoparan-Binding Protein Involving in Ca2+ Release from Skeletal Muscle Sarcoplasmic Reticulum. ...
Mitigating sarcoplasmic reticulum stress limits disuse-induced muscle loss in hindlimb unloaded mice. 11 July 2022 ... Defective endoplasmic reticulum-mitochondria contacts and bioenergetics in SEPN1-related myopathy. 13 July 2020 ... we assessed the overall protein turnover status of the mitochondrial reticulum in skeletal muscle. Consistent with reduced ... bred LONP1 mKO mice with MitoTimer reporter mice to monitor the overall protein turnover status of the mitochondrial reticulum ...
SARCOPLASMIC-RETICULUM; SEQUENCE; SHEEP; Y chromosome diverisity and the genetic architecture of Irish surnames ...
IgE-dependent human basophil responses are inversely associated with the sarcoplasmic reticulum Ca 2+ -ATPase (SERCA) ... Previous studies suggest that the sarcoplasmic reticulum Ca2+-ATPase (SERCA2), which regulates cytosolic calcium levels, may be ... IgE-dependent human basophil responses are inversely associated with the sarcoplasmic reticulum Ca 2+ -ATPase (SERCA). ...
SERCA is a P-type ATPase embedded in the sarcoplasmic reticulum and plays a central role in muscle relaxation. SERCAs function ... A kink in DWORF helical structure controls the activation of the sarcoplasmic reticulum Ca2+-ATPase.. Reddy, U Venkateswara; ...
ER/SR endoplasmic/sarcoplasmic reticulum; black arrow = molecular interaction or activation; dashed black arrow = indirect ... ER/SR endoplasmic/sarcoplasmic reticulum; black arrow = molecular interaction or activation; dashed black arrow = indirect ... In addition, the up-regulation of Ryr and Ip3r genes leads to an increase in calcium release from the endoplasmic reticulum. ... mitochondrial and endoplasmic reticulum. In Cx, and even more in M, a dysregulation of Grin and Cacn gene families, leading to ...
... sensing protein that binds to and modulates the sarcoplasmic reticulum Ca(2+) release channel, ryanodine receptor (RYR). Here ... Calmodulin is a ubiquitous Ca(2+) sensing protein that binds to and modulates the sarcoplasmic reticulum Ca(2+) release channel ... in sarcoplasmic reticulum vesicles, prevented the calmodulin-induced increase in spark frequency. These data suggest that ...
... particularly in the endoplasmic reticulum and the sarcoplasmic reticulum. The endoplasmic reticulum. is a structure inside the ... The sarcoplasmic reticulum. is a structure in muscle cells that assists with muscle contraction and relaxation by releasing and ... A lack of SERCA2 enzyme reduces calcium levels in the endoplasmic reticulum, causing it to become dysfunctional. SERCA2 is ... plasmic reticulum Ca2+-ATPase mutants associated with Darier disease. J Biol Chem. 2006 Aug 11;281(32):22882-95. doi: 10.1074/ ...
The HC appeared to affect the release and accumulation of Ca+2 by the sarcoplasmic reticulum. The authors conclude that changes ...
Interferes with the release of calcium from the sarcoplasmic reticulum [123] Both diarrhea and hepatotoxicity are dose ... Interferes with the release of calcium from the sarcoplasmic reticulum [123] Both diarrhea and hepatotoxicity are dose ...
This is the case with SERCA2 (Sarcoplasmic reticulum Calcium-ATPase 2 pump), which recently hit th... Read full blog post.. ... This gene encodes one of the SERCA Ca(2+)-ATPases, which are intracellular pumps located in the sarcoplasmic or endoplasmic ... enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum ...
Sarcoplasmic Reticulum A10.690.350.800 A10.690.552.500.800. Scimitar Syndrome C14.240.700 C14.240.850.968. C16.131.240.700 ...
High resolution structural evidence suggests the Sarcoplasmic Reticulum forms microdomains with Acidic Stores (lysosomes) in ...
... which is known to release Ca2+ from the sarcoplasmic reticulum. The speed of the perfusion system and the relative absence of ... which is known to release Ca2+ from the sarcoplasmic reticulum. The speed of the perfusion system and the relative absence of ... which is known to release Ca2+ from the sarcoplasmic reticulum. The speed of the perfusion system and the relative absence of ... premature release of Ca2+ from the sarcoplasmic reticulum leads to a transient inward current, which is large enough to ...
... the endoplasmic reticulum is called the sarcoplasmic reticulum. The term motor unit is used to describe a group of muscle ...
... skeletal muscle relaxants inhibit muscle contraction by decreasing calcium release from the sarcoplasmic reticulum in muscle ...
Sarcoplasmic reticulum (terminal cisternae) * What are Transverse Tubules? Invaginations of the sarcolemma that create a ...
... and reduced expression of the sarcoplasmic reticulum calcium ATPase. The DDT-cKO hearts also exhibited diminished angiogenesis ...
In aequorin-loaded, ferret right ventricular papillary muscles, blockers of the sarcolemmal and the sarcoplasmic reticulum Ca2+ ...
Thus the effects of pH(o) cannot be explained solely by changes in pH(i). The role of the sarcoplasmic reticulum (SR) and ...
"Preservation of Structural and Functional Activity in Lyophilized Sarcoplasmic Reticulum," Archives of Biochemistry and ...
Calmodulin can also make use of the calcium stores in the endoplasmic reticulum, and the sarcoplasmic reticulum. It is critical ...
Calcium induced release of calcium from the sarcoplasmic reticulum of skinned skeletal muscle fibres ... Calcium induced release of calcium from the sarcoplasmic reticulum of skinned skeletal muscle fibres ... Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum ... Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum ...
... and calcium release from the sarcoplasmic reticulum in postnatal skeletal muscle. (Springer Nature, 2016-04-11. ) Cong, Xiaofei ... but not caffeine-induced calcium release from the sarcoplasmic reticulum. This study demonstrates that STAC3 is important to ... and excitation-induced calcium release from the sarcoplasmic reticulum in the postnatal skeletal muscle. ...
In the sarcoplasmic reticulum membrane, PLN binds to the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), keeping this ...
... the calcium release channel in sarcoplasmic reticulum responsible for calcium release during excitation-contraction coupling, ...
This is due primarily to altered Ca2+ entry and sarcoplasmic reticulum Ca2+ dealing with. In contrast, N2O and especially xenon ...
  • This enzyme acts as a pump that helps control the level of positively charged calcium atoms (calcium ions) inside cells, particularly in the endoplasmic reticulum and the sarcoplasmic reticulum. (medlineplus.gov)
  • A lack of SERCA2 enzyme reduces calcium levels in the endoplasmic reticulum, causing it to become dysfunctional. (medlineplus.gov)
  • Calmodulin is a ubiquitous Ca(2+) sensing protein that binds to and modulates the sarcoplasmic reticulum Ca(2+) release channel, ryanodine receptor (RYR). (nih.gov)
  • An N-terminal extension of calmodulin, (N+3)calmodulin, that binds to but does not activate RYR at nM [Ca(2+)] in sarcoplasmic reticulum vesicles, prevented the calmodulin-induced increase in spark frequency. (nih.gov)
  • On models of biological membranes, sarcoplasmic reticulum vesicles and isolated myocardial muscles, it has been shown that reactive oxygen species and redox systems of the cell participate in the regulation of calcium transfer through the ion channels of the membranes. (cardioweb.ru)
  • In the sarcoplasmic reticulum membrane, PLN binds to the sarco(endo)plasmic reticulum Ca 2+ -ATPase (SERCA), keeping this enzyme's function within a narrow physiological window. (elifesciences.org)
  • Direct-acting skeletal muscle relaxants inhibit muscle contraction by decreasing calcium release from the sarcoplasmic reticulum in muscle cells. (medscape.com)
  • Sequencing of genes involved in the movement of calcium across human skeletal muscle sarcoplasmic reticulum: continuing the search for genes associated with malignant hyperthermia. (cdc.gov)
  • SERCA is a P-type ATPase embedded in the sarcoplasmic reticulum and plays a central role in muscle relaxation . (bvsalud.org)
  • This gene encodes one of the SERCA Ca(2+)-ATPases, which are intracellular pumps located in the sarcoplasmic or endoplasmic reticula of muscle cells. (novusbio.com)
  • Previous studies suggest that the sarcoplasmic reticulum Ca2+-ATPase (SERCA2), which regulates cytosolic calcium levels, may be inversely associated with airway smooth muscle reactivity in asthma. (kent.ac.uk)
  • This enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen, and is involved in muscular excitation and contraction. (novusbio.com)
  • Organization of junctional sarcoplasmic reticulum proteins in skeletal muscle fibers. (nih.gov)
  • acts on Ca(2+)-induced Ca(2+) release channels of skeletal muscle sarcoplasmic reticulum. (nih.gov)
  • 6. Properties of Ca(2+) release induced by clofibric acid from the sarcoplasmic reticulum of mouse skeletal muscle fibres. (nih.gov)
  • 7. Effect of the organic Ca2+ channel blocker D-600 on sarcoplasmic reticulum Ca2+ uptake in skeletal muscle. (nih.gov)
  • 8. The SH3 and cysteine-rich domain 3 (Stac3) gene is important to growth, fiber composition, and calcium release from the sarcoplasmic reticulum in postnatal skeletal muscle. (nih.gov)
  • 14. Effects of dantrolene and its derivatives on Ca(2+) release from the sarcoplasmic reticulum of mouse skeletal muscle fibres. (nih.gov)
  • In skeletal muscle, Dantrium dissociates the excitation-contraction coupling, probably by interfering with the release of Ca++ from the sarcoplasmic reticulum. (nih.gov)
  • Electron microscopy image of a mitochondrion with a donut hole (cyan) as well as sarcoplasmic reticulum (magenta), transverse tubules (orange), and contractile A-bands (green), I-bands (red), and Z-disks (blue) from a mouse glycolytic skeletal muscle. (nih.gov)
  • Normal cardiac contraction depends on the maintenance of calcium cycling and homeostasis across the mitochondrial membrane and sarcoplasmic reticulum during each cardiac cycle. (medscape.com)
  • Inhibition of calcium release from the sarcoplasmic reticulum by Dantrium reestablishes the myoplasmic calcium equilibrium, increasing the percentage of bound calcium. (nih.gov)
  • The sarcoplasmic reticulum provides the intracellular storage and release of calcium required for contraction to occur. (medscape.com)
  • The electrical signals conducted by the T-tubules stimulate the sarcoplasmic reticulum to release calcium. (medscape.com)
  • Heart muscle contraction is normally activated by a synchronized Ca release from sarcoplasmic reticulum (SR), a major intracellular Ca store. (nih.gov)
  • Here, we report that nanomolar concentrations of EGCG significantly enhance contractility of intact murine myocytes by increasing electrically evoked Ca(2+) transients, sarcoplasmic reticulum (SR) Ca(2+) content, and ryanodine receptor type 2 (RyR2) channel open probability. (nih.gov)
  • The HC appeared to affect the release and accumulation of Ca+2 by the sarcoplasmic reticulum. (cdc.gov)
  • 15. Sarcoplasmic reticulum Ca2+ release declines in muscle fibers from aging mice. (nih.gov)