Local calcium transients triggered by single L-type calcium channel currents in cardiac cells

José Ramón López-López, Philip S. Shacklock, C. William Balke, Withrow Gil Wier

Research output: Contribution to journalArticlepeer-review

419 Scopus citations

Abstract

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 [Ca 2+]i transients varied as predicted if Ca2+ release from the sarcoplasmic reticulum (SR) was linked tightly to Ca 2+ 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 Ca 2+ channel.

Original languageEnglish
Pages (from-to)1042-1045
Number of pages4
JournalScience
Volume268
Issue number5213
DOIs
StatePublished - 1995

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