Publication Date:
1995-05-19
Description:
The control of calcium release from intracellular stores (the sarcoplasmic reticulum) in cardiac muscle was examined with the use of a confocal microscope and voltage clamp techniques. Depolarization evoked graded calcium release by altering the extent of spatial and temporal summation of elementary calcium release events called "calcium sparks." These evoked sparks were triggered by local L-type calcium channel currents in a stochastic manner, were similar at different potentials, and resembled spontaneous calcium sparks. Once triggered, the calcium release from the sarcoplasmic reticulum during a calcium spark was independent of the duration of the triggering calcium influx. These results were used to develop a unifying model for cardiac excitation-contraction coupling that explains the large (but paradoxically stable) amplification of the trigger calcium influx by a combination of digital and analog behavior.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cannell, M B -- Cheng, H -- Lederer, W J -- HL25675/HL/NHLBI NIH HHS/ -- HL36974/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1995 May 19;268(5213):1045-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology and Clinical Pharmacology, St. George's Hospital Medical School, London, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7754384" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Calcium/*metabolism
;
Calcium Channels/*physiology
;
In Vitro Techniques
;
Ion Channel Gating/physiology
;
Membrane Potentials/physiology
;
Microscopy, Confocal
;
Muscle Proteins/physiology
;
Myocardium/*metabolism
;
Patch-Clamp Techniques
;
Probability
;
Rats
;
Ryanodine Receptor Calcium Release Channel
;
Sarcoplasmic Reticulum/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
