Publication Date:
1995-05-19
Description:
Excitation-contraction coupling was studied in mammalian cardiac cells in which the opening probability of L-type calcium (Ca2+) channels was reduced. Confocal microscopy during voltage-clamp depolarization revealed distinct local transients in the concentration of intracellular calcium ions ([Ca2+]i). When voltage was varied, the latency to occurrence and the relative probability of occurrence of local [Ca2+]i transients varied as predicted if Ca2+ release from the sarcoplasmic reticulum (SR) was linked tightly to Ca2+ flux through L-type Ca2+ channels but not to that through the Na-Ca exchanger or to average [Ca2+]i. Voltage had no effect on the amplitude of local [Ca2+]i transients. Thus, the most efficacious "Ca2+ signal" for activating Ca2+ release from the SR may be a transient microdomain of high [Ca2+]i beneath an individual, open L-type Ca2+ channel.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lopez-Lopez, J R -- Shacklock, P S -- Balke, C W -- Wier, W G -- HL02466/HL/NHLBI NIH HHS/ -- HL29473/HL/NHLBI NIH HHS/ -- HL50435/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1995 May 19;268(5213):1042-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Maryland, School of Medicine, Baltimore 21201, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7754383" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Calcium/*metabolism
;
Calcium Channels/drug effects/*physiology
;
Electric Stimulation
;
Guinea Pigs
;
In Vitro Techniques
;
Ion Channel Gating/physiology
;
Membrane Potentials/physiology
;
Microscopy, Confocal
;
Myocardium/*metabolism
;
Patch-Clamp Techniques
;
Probability
;
Sarcoplasmic Reticulum/metabolism
;
Verapamil/pharmacology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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