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目的研究苄基四氢巴马汀(BTHP)的抗心律失常机理.方法采用全细胞膜片钳技术记录心室肌细胞慢激活延迟整流钾电流(IKs)及其尾电流(IKs,tail).结果 BTHP在1～100 μmol*L-1的范围内以浓度依赖性、电压依赖性和频率依赖性方式阻滞IKs,tail,其IC50为9.3 μmol*L-1(95%可信限:7.8～11.8 μmol*L-1).BTHP 30 μmol*L-1可使IKs及IKs,tail分别降低(40±6)%和(39±5)% (P<0.01).BTHP可以抑制IKs,tail.该药主要使IKs,tail的失活时间常数缩短,从而使IKs,tail失活速度增加,而对IKs,tail的激活动力学影响不大.结论 BTHP对IKs有明显的抑制作用.“,”AIM To clarity the antiarrhythmic mechanisms of benzyltetrahydropalmatine (BTHP). METHODS Delayed rectifier potassium current (IKs) was recorded by using whole-cell patch clamp technique. RESULTS IKs was blocked by BTHP (1-100 μmol*L-1) in concentration-, voltage- and frequency-dependent fashion with an IC50 9.3 μmol*L-1 (95% confidence range: 7.8-11.8 μmol*L-1). BTHP 30 μmol*L-1 reduced IKs and its tail current(IKs,tail) by (40±6)% and (39±5)% (P<0.01). Time constants of deactivation of IKs,tail were reduced by BTHP, with accelerating deactivation course of IKs,tail. CONCLUSION BTHP inhibited IKs in isolated guinea pig ventricular myocytes.