Molecular and Cellular Biochemistry

, Volume 160, Issue 1, pp 61–66

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


  • Elisabeth Fantini
    • Laboratoire de Physiologie Faculté de Médecine
  • Pierre Athias
    • Laboratoire de Physiologie Faculté de Médecine
  • Régine Tirosh
    • Laboratory for Myocardial ResearchThe Hebrew University-Hadassah Medical School
  • Arié Pinson
    • Laboratory for Myocardial ResearchThe Hebrew University-Hadassah Medical School

DOI: 10.1007/BF00240032

Cite this article as:
Fantini, E., Athias, P., Tirosh, R. et al. Mol Cell Biochem (1996) 160: 61. doi:10.1007/BF00240032


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 cardiomyocytesion channel toxinTaiCatoxincardiac action potentialcardiac automacityarrhythmiasphospholipase A2
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© Kluwer Academic Publishers 1996