长春西汀对大鼠心肌细胞钠电流的抑制作用

目的：研究长春西汀对心肌细胞钠电流的作用。方法：用全细胞膜片箝技术记录大鼠心肌细胞钠电流。结果：长春西汀可逆性抑制心肌细胞钠电流的作用为剂量依赖性和电压依赖性，但未发现频率或使用依赖性。长春西汀１０－８０μｍｏｌ·Ｌ＾－１，对钠电流的抑制作用为１３％±２％至７５％±６％，半数抑制浓度ＩＣ５０值（９５％可信限）为３６．４（２８．１－４７．１）μｍｏｌ·Ｌ＾－１，在膜电位以１０ｍＶ的间隔从－９０ｍＶ阶

Inhibitory effects of vinpocetine on sodium current in rat cardiomyocytes.

AIM: To study the effects of vinpocetine (Vin) on the sodium current (INa) in cardiomyocytes. METHODS: The sodium current in adult rat ventricular myocytes was measured by whole cell patch-clamp technique. RESULTS: The INa in cardiomyocytes was blocked reversibly by Vin, in concentration-dependent and voltage-dependent manner, but not rate- or use-dependent. The INa was attenuated by 13%-75% when the Vin concentration was raised from 10 to 80 mumol.L-1. The IC50 (95% confidence limits) was 36.4 (28.1-47.1) mumol.L-1. When the membrane potential depolarized over the range of -90 mV to +40 mV in 10-mV step, inhibitory effect of Vin on the INa was 39% at first, then maintained at a higher level, about 52% +/- 5%. The maximal depression (57%) reached at about 0 mV. Vin influenced both the activation and inactivation processes of sodium channel, and resulted in attenuation of the window currents (the slowly inactivating sodium currents). CONCLUSION: Vin inhibited sodium currents in rat ventricular myocytes.