摘要
本文试图从细胞水平上探讨毛冬麦甲素对心肌的作用机理。实验取豚鼠右心室乳头肌作离体恒速灌流,用电驱动诱发其动作电位,以玻璃微电极引导,观察动作电位复极化时程和有效不应期等变化。实验结果表明:毛冬青甲素有延长APD50、APD_(90)和ERP的作用;硝苯吡啶能全部阻断毛冬青甲素延长APD和ERP的效应:酚妥拉明能使毛冬青甲素的效应减弱;心得安基本不影响毛冬青甲素延长APD和ERP的作用.提示毛冬青甲素主要通过激活钙通道,促进Ca^(++)内流起作用;其作用可能与α受体有关,但与β受体基本无关.
The performing mechanisms of Ilexonin A (IA) on myocardium were studied on the cell's level. Papillary muscle cells were perfused by constant speed. Action potential were evoked by electrical stimulation and examined by means of glass microelectrodes. The results indicated that APD50, APD90, and ERP were prolonged by IA; the effects of IA were completely blocked by nifedipine or partly by phentolamine, but rarely by propranolol. The results suggest that IA can promote Ca^(++) inflow mainly by activating 'Calcium slow channel', α-receptor in the myocardium may be the medium.
关键词
毛冬青甲素
心肌
药物作用
ILEX PUBESCENS/pbarmacodynamicsMYOCARDIUM/drug effectsELECTROMYOGRAPHA
