苄基四氢巴马汀对豚鼠心室肌细胞慢激活延迟整流钾电流及其尾电流的作用(英文)

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～ 10 0 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 9.3μmol·L- 1(95 %可信限 :7.8～11.8μmol·L- 1)。BTHP 30 μmol·L- 1可使IKs 及IKs,tail分别降低 (40± 6 ) %和 (39± 5 ) % (P <0 .0 1)。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。

Effects of benzyltetrahydropalmatine on slowly activating component of delayed rectifier K+ current and its tail current in guinea pig ventricular myocytes

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.