Biomaterial Database

Effects of rest interval on the release of calcium from the sarcoplasmic reticulum in isolated guinea pig ventricular myocytes. 1995

C M Terracciano, and R U Naqvi, and K T MacLeod

Department of Cardiac Medicine, National Heart and Lung Institute, University of London, UK.

Guinea pig cardiac myocytes were loaded with the fluorescent dye indo 1, and cell contraction was measured by a video edge-detection system. Ca2+ was released from the sarcoplasmic reticulum (SR) by rapidly cooling the myocytes or by rapid application of 10 mmol/L caffeine. Estimates of the amount of Ca2+ released from the SR after different rest intervals (ie, under different loading conditions) were obtained by measuring the current evoked by rapid application of 10 mmol/L caffeine, which we call Na+/Ca2+ exchange current. This current is completely inhibited by removal of extracellular Na+ and Ca2+ or by application of 5 mmol/L Ni2+. SR Ca2+ release after rest intervals of 5 to 120 seconds (assuming cell volume to be 30 x 10(-12) L) was estimated to be 57.8 +/- 5.7 to 25.7 +/- 4.5 mumol/L accessible cell volume, respectively, equivalent to 23 to 10 mumol/kg wet wt, respectively. There was an exponential decline in Ca2+ release from the SR after rest intervals of 2 to 120 seconds (rate constant, 0.029 s-1; t1/2, 24 seconds); thereafter, there remained a portion (56%) of Ca2+ releasable to caffeine application. We found a similar exponential decay (rate constant, 0.020 s-1; t1/2, 35 seconds) of the size of rapid cooling contractures with increasing rest intervals. The time to peak of the Na+/Ca2+ exchange current in the presence of caffeine slowed at long rest intervals, ie, at smaller SR loads. A decrease in SR load of 50% increased the time to peak of the exchange current by 213 +/- 37% (n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007211	Indoles	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.
D010936	Plant Extracts	Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.	Herbal Medicines,Plant Extract,Extract, Plant,Extracts, Plant,Medicines, Herbal
D010946	Plants, Medicinal	Plants whose roots, leaves, seeds, bark, or other constituent parts possess therapeutic, tonic, purgative, curative or other pharmacologic attributes, when administered to man or animals.	Herbs, Medicinal,Medicinal Herbs,Healing Plants,Medicinal Plants,Pharmaceutical Plants,Healing Plant,Herb, Medicinal,Medicinal Herb,Medicinal Plant,Pharmaceutical Plant,Plant, Healing,Plant, Medicinal,Plant, Pharmaceutical,Plants, Healing,Plants, Pharmaceutical
D012146	Rest	Freedom from activity.	Rests
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
D002469	Cell Separation	Techniques for separating distinct populations of cells.	Cell Isolation,Cell Segregation,Isolation, Cell,Cell Isolations,Cell Segregations,Cell Separations,Isolations, Cell,Segregation, Cell,Segregations, Cell,Separation, Cell,Separations, Cell
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D005456	Fluorescent Dyes	Chemicals 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.	Flourescent Agent,Fluorescent Dye,Fluorescent Probe,Fluorescent Probes,Fluorochrome,Fluorochromes,Fluorogenic Substrates,Fluorescence Agents,Fluorescent Agents,Fluorogenic Substrate,Agents, Fluorescence,Agents, Fluorescent,Dyes, Fluorescent,Probes, Fluorescent,Substrates, Fluorogenic
D006168	Guinea Pigs	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.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea