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目的：研究依那普利（Ｅｎａ）对豚鼠乳头状肌电生理特性，哇巴因诱发的延迟后除极（ＤＡＤ）和触发电活动（ＴＡ）的直接作用．方法与结果：采用标准玻璃微电极技术记录豚鼠乳头状肌动作电位．Ｅｎａ呈浓度依赖性增加静息膜电位（ＲＰ）和动作电位幅度（ＡＰＡ），而对０期最大除极，超射，和动作电位时程无明显影响．Ｅｎａ１０μｍｏｌ·Ｌ－１则可明显抑制哇巴因０５μｍｏｌ·Ｌ－１诱发的ＤＡＤ和ＴＡ，ＤＡＤ幅度分别由５３±２３，５９±２８，７４±２１和８９±１３降至２６±０７，３１±１０，３７±１５和５３±１１（ｍＶ）（Ｐ均＜００１），刺激周长为２００ｍｓ时ＴＡ数目由３６±０７降至０８±０２（Ｐ＜００５）．结论：Ｅｎａ通过增加心肌细胞ＲＰ和ＡＰＡ抑制哇巴因诱发豚鼠乳头状肌ＤＡＤ和ＴＡ．
AIM: To investigate the direct effect of enalapril on the electrophysiological properties of guinea pig papillary muscles, ouabain induced delayed depolarization (DAD) and triggered electrical activity (TA). Methods and Results: The action potentials of guinea pig papillary muscles were recorded by standard glass microelectrode technique. Ena increased resting membrane potential (RP) and action potential amplitude (APA) in a concentration-dependent manner, but had no significant effect on maximal depolarization, over shoot and action potential duration. Ena10μmol·L-1 could obviously inhibit the DAD and TA induced by 0 5μmol·L-1 ouabain, and the ranges of DAD were 53 ± 23, 59 ± 28, 74 ± 2 1 and 89 ± 13 decreased to 26 ± 07, 31 ± 10, 37 ± 15 and 53 ± 11 (mV) (P < 001). When the circumference of stimulation was 200ms, the number of TA decreased from 3.6 ± 0.7 to 08 ± 02 (P <005). CONCLUSION: Ena inhibits ouabain-induced DAD and TA in guinea pig papillary muscles by increasing cardiomyocytes RP and APA.