Excitation-contraction coupling in the heart: The state of the question

M. D. Stern, E. G. Lakatta

Research output: Contribution to journalReview articlepeer-review

Abstract

Recent developments have led to great progress toward determining the mechanism by which calcium is released from the sarcoplasmic reticulum in the heart. The data support the notion of calcium-induced calcium release via a calcium-sensitive release channel. Calcium release channels have been isolated and cloned. This situation creates a paradox, as it has also been found that calcium release is smoothly graded and closely responsive to sarcolemmal membrane potential, properties that would not be expected of calcium-induced calcium release, which has intrinsic positive feedback. There is, therefore, no quantitative understanding of how the properties of the calcium release channel can lead to the macroscopic physiology of the whole cell. This problem could, in principle, be solved by various schemes involving heterogeneity at the ultrastructural level. The simplest of these require only that the sarcolemmal calcium channel be located in close proximity to one or more sarcoplasmic reticulum release channels. Theoretical modeling shows that such arrangements can, in fact, resolve the positive feedback paradox. An agenda is proposed for future studies required in order to reach a specific, quantitative understanding of the functioning of calcium-induced calcium release.

Original languageEnglish (US)
Pages (from-to)3092-3100
Number of pages9
JournalFASEB Journal
Volume6
Issue number12
DOIs
StatePublished - Jan 1 1992

Keywords

  • calcium
  • channels
  • excitation-contraction coupling
  • heart
  • sarcoplasmic reticulum

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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