中文摘要：

目的研究步长稳心颗粒对家兔左心室肌细胞瞬时外向钾电流（Ito）的影响,探讨稳心颗粒抗心律失常的作用机制。方法应用全细胞膜片钳技术,分别记录稳心颗粒组和对照组家兔内层（Endo）、中层（M）和外层（Epi）心室肌细胞的Ito,观察稳心颗粒对家兔心室肌细胞Ito的影响。结果在测试电压＋50 mV时,对照组Epi、M和Endo细胞的Ito分别为（4 235.7±953.2）pA（n=11）、（4 115.8±743.1）pA（n=11）和（2 730.2±524.6）pA（n=11）,Endo细胞的Ito电流强度明显小于Epi和M细胞（P〈0.01）;稳心颗粒灌胃给药后家兔左心室肌Epi、M和Endo细胞的Ito电流强度分别为（4 806.4±1 381.8）pA（n=11）、（4 661.3±902.6）pA（n=11）和（4 072.9±1 234.9）pA（n=11）,与对照组相比稳心颗粒可明显增加Endo细胞Ito的电流强度（P〈0.01）。结论稳心颗粒增加Endo心室肌细胞Ito的电流强度,使心室的跨壁复极离散度（TDR）减小,这可能是其抗心律失常的重要机制之一。

英文摘要：

Objective To investigate the effect of Buchang Wenxin（BCWX） granules on the transient outward potassium current（Ito） in left ventricular cardiomyocytes of rabbits and explore the antiarrhythmic mechanism of BCWX granules.Methods Whole-cell patch clamp technique was used to record Ito of epicardium（Epi）,middle（M） and endocardium（Endo） of rabbits with BCWX granule group and control group,respectively.Results When the test potential was ＋50 mV,the intensity of Ito was（4 235.7±953.2）pA（n=11） in Epi,（4 115.8±743.1）pA（n=11） in M and（2 730.2±524.6）pA（n=11） in Endo.The values of Endo were significantly lower than those of M and Epi（P〈0.01）.After BCWX granules treatment,the intensity of Ito was（4 806.4±1 381.8）pA（n=11） in Epi,（4 661.3±902.6）pA（n=11） in M and（4 072.9±1 234.9）pA（n=11） in Endo.BCWX granules could significantly increase the intensity of Ito in Endo（P〈0.01）.Conclusion BCWX granules can increase the intensity of Ito in Endo of left ventricular cardiomyocytes,thus leading to the reduced transmural dispersion of repolarization.This may be responsible for antiarrhythmic effect of BCWX granules.