索他洛尔对培养乳鼠心肌细胞自发性搏动及动作电位的影响

观察了索他洛尔对培养乳鼠心肌细胞的作用，索他洛尔３－３００μｍｏｌＬ－１引起心肌细胞簇搏动频率浓度依赖性减小，３和３０μｍｏｌＬ－１能部分对抗乌头碱的正性频率作用，３０μｍｏｌＬ－１也能部分对抗毒毛花苷Ｇ的正性频率作用，索他洛尔３和３０μｍｏｌＬ－１延长５０％和９０％动作电位时程和搏动周期长度．结果提示，索他洛尔的抗心律失常作用与抑制Ｋ＋外流有关，也可能抑制Ｎａ＋内流．

Effects of sotalol on spontaneous beating and action potentials of cultured myocardial cells of neonatal rats

Effects of sotalol on spontaneous beating and action potentials of cultured myocardial cells of neonatal rats were observed. Sotalol 3-300 μmol·L^-1 resulted in a dose-dependent decrease in the beating rates. The steady state of inhibition of beating rates was achieved at 20 min after addition of sotalol and might last for over 60 min. Pretreated with sotalol 30 μmol·L^-1 could protect partially the positive chronotropic effects of aconitine 0.2 mg·L^-1 or strophantin G 0.5 mg·L^-1. Sotalol 3 and 30 μmol·L^-1 prolonged action potential duration at 50% and at 90% repolarization,and the beating cycle length. The results suggest that the antiarrhythmic mechanism of sotalol may be related to its inhibitory effects on K⁺, Na⁺ channels.