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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～ 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。
Objective To study the antiarrhythmic mechanism of benzyltetrahydropalmatine (BTHP). Methods Whole-cell patch-clamp technique was used to record slow activation of delayed rectifier potassium currents (IKs) and tail currents (IKs, tail) in ventricular myocytes. Results BTHP blocked IKs and tail in a concentration-dependent, voltage-dependent and frequency-dependent manner in the range of 1-10 μmol·L-1 with an IC50 of 9.3 μmol·L-1 (95% confidence limit: 7.8 ~ 11.8μmol·L-1). BTHP 30 μmol·L-1 reduced IKs and IKs, tail by (40 ± 6)% and (39 ± 5)%, respectively (P <0.01). BTHP can inhibit IKs, tail. The drug mainly to IKs, tail inactivation time constant shortened, so IKs, tail inactivation rate increased, while IKs, tail activation kinetics little effect. Conclusion BTHP has a significant inhibitory effect on IKs.