Molecular and Cellular Biochemistry

, Volume 160, Issue 1, pp 61–66 | Cite as

Effect of TaiCatoxin (TCX) on the electrophysiological, mechanical and biochemical characteristics of spontaneously beating ventricular cardiomyocytes

  • Elisabeth Fantini
  • Pierre Athias
  • Régine Tirosh
  • Arié Pinson
Article

Abstract

TaiCatoxin (TCX), a complex toxin isolated from Taipan snake venom, is believed to have a specific blocking activity on voltage-dependent cardiac calcium channels. The aim of this study was to investigate the effects of TCX on a broad range of heart muscle cell functions, i.e. electrophysiology, contractility, automaticity and the related biochemical modifications. Myocyte-enriched cultures were prepared from newborn rat heart ventricles. The transmembrane potentials were recorded with glass microelectrodes. The contractions were monitored photometrically. TCX decreased the action potential amplitudes, mainly by lowering the plateau. The action potential duration and the contraction parameters were decreased. Although TCX has a minor overall negative chronotropic effect, it evoked transient but severe arrhythmias and prolonged changes in the intercellular electrical coupling. Moreover, the action of TCX appeared to be dose-dependent. These effects are consistent with a specific blockade of the L-type, voltage-dependent calcium channels, but effects of other components of the toxin complex cannot be excluded. TCX also exhibits phospholipase A2 activity leading to the release of lysophospholipids and FFA (acyl CoA and acyl carnitine), which have detrimental effects on cellular integrity and function.

Key words

cultured cardiomyocytes ion channel toxin TaiCatoxin cardiac action potential cardiac automacity arrhythmias phospholipase A2 

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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Elisabeth Fantini
    • 1
  • Pierre Athias
    • 1
  • Régine Tirosh
    • 2
  • Arié Pinson
    • 2
  1. 1.Laboratoire de Physiologie Faculté de MédecineDijonFrance
  2. 2.Laboratory for Myocardial ResearchThe Hebrew University-Hadassah Medical SchoolJerusalemIsrael

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