Effect of transient stretch on intracellular Ca2+ during triggered propagated contractions in intact trabeculae

Masahito Miura, Y. Wakayama, Y. Sugai, Yutaka Kagaya, J. Watanabe, H. E.D.J. Ter Keurs, K. Shirato

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Transient stretch of cardiac muscle during a twitch contraction may dissociate Ca2+ from myofilaments into the cytosol at the moment of quick release of the muscle. We studied the effect of stretch and quick release of trabeculae on changes in intracellular Ca2+ ([Ca2+]i) during triggered propagated contractions (TPCs). Trabeculae were dissected from the right ventricle of 9 rat hearts. [Ca2+]i was measured using electrophoretically injected fura-2. Force was measured using a silicon strain gauge and sarcomere length was measured using laser diffraction techniques. Reproducible TPCs (n = 13) were induced by trains of electrical stimuli (378 ± 19 ms interval) for 7.5 s at [Ca2+]0 of 2.0 mM (27.9 ± 0.2°C). The latency of the TPC force and the underlying increase in [Ca2+]i was calculated from the time (TimeF) between the last stimulus and the peak of TPC force (PeakF), or the time (TimeCa) between the last stimulus and the peak of the increase in [Ca2+]i during the TPCs (PeakCa). As a result of a 10% increase in muscle length for 150-200 ms during the last stimulated twitches, TimeF and TimeCa decreased and PeakF and PeakCa increased significantly (n = 13). In addition, transient stretch sometimes induced a twitch contraction subsequent to the accelerated TPC and its underlying increase in [Ca2+]i. These results suggest that Ca2+ binding and dissociation from the myofilaments by the stretch and quick release of muscle may modulate the TPC force and the underlying increases in [Ca2+]i and play an important role in the induction of arrhythmias.

Original languageEnglish
Pages (from-to)68-72
Number of pages5
JournalCanadian Journal of Physiology and Pharmacology
Volume79
Issue number1
DOIs
Publication statusPublished - 2001 Feb 22

Keywords

  • Calcium transients
  • Rat cardiac trabeculae
  • Stretch

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Effect of transient stretch on intracellular Ca<sup>2+</sup> during triggered propagated contractions in intact trabeculae'. Together they form a unique fingerprint.

  • Cite this