The rate of tension recovery in cardiac muscle correlates with the relative residual tension prevailing after restretch

Kenneth S. Campbell, Anastasia M. Holbrook

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Isolated cardiac muscles generate tension more quickly at higher levels of Ca2+ activation. We investigated the molecular mechanisms underlying this effect in permeabilized rat myocardial preparations by measuring the rate of tension recovery following brief shortening/restretch perturbations. Separate series of experiments used Ca2+-activating solutions with different pH values (pH 6.75, 7.00, and 7.25) and different phosphate (Pi) concentrations (0, 2.5, and 5.0 mM added Pi) to modulate the recovery kinetics. Subsequent analysis showed that the rate of tension recovery correlated (P < 0.001) with the relative residual tension, that is, the minimum tension measured immediately after restretch normalized to the steady-state isometric tension for the experimental condition. This new finding suggests that the rate at which cardiac muscles develop force increases with the proportion of cross bridges bound to the thin filament and is strong evidence of cooperative contractile activation.

Original languageEnglish
Pages (from-to)H2020-H2022
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume292
Issue number4
DOIs
StatePublished - Apr 2007

Keywords

  • Cardiac contractility and energetics
  • Muscle contraction
  • Myocardial contractility

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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