莫雷西嗪对心室肌细胞的电生理影响

Electrophysiolgic effect of moricizine on ventricular myocytes

应用微电极技术和膜片钳全细胞记录,研究莫雷西嗪(MRZ)对豚鼠心室肌细胞电生理影响.结果表明:(1)MRZ能降低正常心肌V_(max)和APA,缩短APD,其作用呈浓度和频率依赖,对静息电位无影响;(2)MRZ阻断心肌快钠流(I_(Na))和L型钙流(L-I_(Ca)),亦呈浓度依赖,对背景钾流(I_(K_1))无影响;(3)MRZ对I_(Na)、L-I_(Ca)通道的阻滞,主要作用于失活门控,使失活时间延长.提示MRZ基本属于I_B类药物,对细胞电生理影响通过对钠、钙通道阻滞而实现.

Using microelectrode techique and patch clamp whole cell recording, author studied electrophysiologic effect of moricizine (MRZ) on ventricular myocytes of guinea pig. Results indicated: (1) MRZ could reduce Vmax and APA of normal ventricular myocytes, shorten APD with dose and frequence dependence, but had no influence on RP; (2)MRZ could block IN, and L-Ic2, of ventricular cells with dose dependence, but did not affect IK1; (3) MRZ exerted chief effect on inactivated gate-control of Na+ channel and Ca++ channel, prolonged inactivated duration. These results suggested that MRZ belonged to IB group. Electrophysiolgic effects of MRZ arised from block ade of Na+ channel and Ca+ + channel.