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 Ca2+ 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 ETA receptor.
|Original language||English (US)|
|Number of pages||8|
|Journal||Acta Physiologica Sinica|
|State||Published - Jul 10 1997|
- Atriopeptin III
- Papillary muscle
ASJC Scopus subject areas