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Effects of endothelin on electrophysiological and contractile activity of guinea pig papillary muscles

Zhang Zhao, Li Yulong, He Ruirong

Department of Physiology, Institute of Basic Medicine, Hebei Medical University. Shijiazhuang 050017, Hebei

Abstract

Effects of endothelin on electrophysiological activity and contractility were examined in guinea pig papillary muscle using intracellular microelectrode and contractile tension recording technique. The results indicated that ET-1 prolonged APD, especially PPD and increased the contractile tension in a dose-dependent manner. The ET-induced effects were not influenced by K~(+) channel blocker TE_(A), but inhibited by L-type CA~(2+) channel blocker nifedipine, ET_(A) receptor selective antagonist BQ-123 and atriopeptin Ⅲ in a concentration-dependent manner. It is suggested that the changes in electrophysiological activity and the positive inotropic effect induced by ET-1 in guinea pig muscles are due to the elevation of intracellular calcium, which may be mediated by ET_(A) receptor.

Key words: Endothelin;BQ-123;TEA;Nifedipine;AtriopeptinⅢ;Pepillary muscle;Electrophysiology

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Citing This Article：

Zhang Zhao, Li Yulong, He Ruirong. Effects of endothelin on electrophysiological and contractile activity of guinea pig papillary muscles. Acta Physiol Sin 1997; 49 (2): (in Chinese with English abstract).