Biomaterial Database

Characterization of Ca2+ release from the cardiac sarcoplasmic reticulum. 1983

N S Dhalla, and P V Sulakhe, and J M Lamers, and P K Ganguly

The characteristics of Ca2+ release in relation to Ca2+ binding were studied in sarcoplasmic reticulum vesicles isolated from canine myocardium. The Ca2+ binding appeared to be dependent on ATP as a 4 fold increase in Ca2+ binding was observed upon the addition of ATP. In the presence of a suboptimal ATP concentration (20 mumol/l; without ATP regenerating system) a rapid release of Ca2+ started within 2 min. The rate of Ca2+ release was increased by increasing the concentration of Ca2+ in the preincubation medium when studied by diluting preloaded vesicles in medium free of Ca2+ and ATP; an apparent saturation was reached at 5 mmol/l Ca2+ but Ca2+ release again increased between 5 and 10 mmol/l Ca2+. High pH (8.0) enhanced the Ca2+ release process. When Ca2+ loaded vesicles were treated with various phospholipases and proteases, an enhanced Ca2+ release was observed in comparison to the control values. The release of Ca2+ was also increased by pharmacological agents like caffeine, ether and halothane. The Ca2+ release rate was stimulated by the p-chloromercurybenzoate treatment, which decreased ATP dependent Ca2+ binding and Ca2+-stimulated ATPase activities of the sarcoplasmic reticulum vesicles. The effect of temperature when evaluated by Arrhenius plots showed a higher energy of activation of Ca2+ release (66.15 kJ/mol) in comparison to that for Ca2+ binding (41.03 kJ/mol). These results indicate that, although Ca2+ release and Ca2+ binding activities of the cardiac sarcoplasmic reticulum appears to be related, Ca2+ release is probably a distinct process and is controlled differently. It seems that the Ca2+ release site in sarcoplasmic reticulum membranes is lipoprotein in nature.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009206	Myocardium	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.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D010447	Peptide Hydrolases	Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.	Peptidase,Peptidases,Peptide Hydrolase,Protease,Proteases,Proteinase,Proteinases,Proteolytic Enzyme,Proteolytic Enzymes,Esteroproteases,Enzyme, Proteolytic,Hydrolase, Peptide
D010740	Phospholipases	A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.	Lecithinases,Lecithinase,Phospholipase
D002110	Caffeine	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.	1,3,7-Trimethylxanthine,Caffedrine,Coffeinum N,Coffeinum Purrum,Dexitac,Durvitan,No Doz,Percoffedrinol N,Percutaféine,Quick-Pep,Vivarin,Quick Pep,QuickPep
D002118	Calcium	A basic element found in nearly all 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.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002132	Calcium Radioisotopes	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.	Radioisotopes, Calcium
D004285	Dogs	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)	Canis familiaris,Dog
D004986	Ether	A mobile, very volatile, highly flammable liquid used as an inhalation anesthetic and as a solvent for waxes, fats, oils, perfumes, alkaloids, and gums. It is mildly irritating to skin and mucous membranes.	Diethyl Ether,Ether, Ethyl,Ethyl Ether,Ether, Diethyl
D006221	Halothane	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)	1,1,1-Trifluoro-2-Chloro-2-Bromoethane,Fluothane,Ftorotan,Narcotan