[Synchronous investigation of the effects of vesnarinone on action potential and muscle tension of isolated rabbit's ventricular papillary muscle].

This study adopted intracellular microelectrode technique to observe synchronously the effects of vesnarinone on intracellular potential and muscle tension of isolated rabbit's ventricular papillary muscle and analysed their variation. The results showed that vesnarinone increased the Tmax (P < 0.01) and Tdv/dt (P < 0.01) of isolated rabbit's ventricular papillary muscle and prolonged the action potential time (APT) without obvious effects on RP, APA and Vmax of papillary muscle. The relationship between them (r = 0.994, P < 0.05), suggesting that their changes be of the same mechanism and probably relate to the increase of inward calcium current.