醋柳黄酮对大鼠心室肌细胞瞬间外向整流钾电流的影响

Effect of TFH on transient outward potassium currents in isolated ventricular myocytes of rats

目的探讨醋柳黄酮对大鼠心室肌细胞膜瞬间外向钾电流(Ito)的影响。方法用急性酶解法获得单个大鼠心室肌细胞,标准的全细胞膜片钳技术记录瞬间外向钾电流。结果①醋柳黄酮呈浓度和电压依赖性抑制Ito,在+50mV时,0.06、0.1和0.14g.L-1醋柳黄酮分别阻断Ito峰电流(18.34±0.99)%、(25.32±1.43)%和(38.88±1.96)%。②0.14g.L-1醋柳黄酮使Ito失活曲线明显左移,但对激活和复活曲线无影响。结论醋柳黄酮呈浓度和电压依赖性抑制心肌细胞Ito,这可能是其抗心律失常作用的重要机制之一。

Aim The effects of total flavones of Hippophae Rhamnoides L（TFH） on transient outward potassium current（Ito） in isolated ventricular myocytes of rats were determined to explore the mechanism of its antiarrhythmic efficacy at the ionic channel level.Methods Single ventricular myocytes of rats were isolated by enzymatic dissociation.The whole-cell patch-clamp recording technique was used to record the change of Ito influenced by TFH.Results TFH decreased Ito in a dose-dependent and voltage-dependent manner in ventricular myocytes of rats.The peak of current-voltage curve was significantly decreased,0.06,0.10,0.14 mg.kg^-1 TFH decreased（18.34±0.99）%,（25.32±1.43）% and（38.88±1.96）%,respectively.The steady-state inactivation curve of Ito was shifted to more negative potentials,the voltage at half-inactivation changing from（-33.62±1.41） mV in control to（-39.83±0.53） mV in the presence of TFH.The activation and recovery curves of Ito were not obviously altered.Conclusion TFH concentration-and voltage-dependently decreased Ito in ventricular myocytes.Therefore,the effect of inhibitory Ito of TFH plays a vital role in its antiarrhythmic efficacy.