Kotake H, Matsuoka S, Ogino K, Takami T, Hasegawa J, Mashiba H
J Pharmacol Exp Ther. 1987 Jun;241(3):982-6.
Effects of cibenzoline (0.1-30 microM) on membrane potentials and currents were investigated in rabbit sinoatrial node cells using conventional microelectrode and double microelectrode voltage clamp methods. Cibenzoline reduced the heart rate, the maximum rate of rise and the action potential amplitude in a dose-dependent manner. At the same time, the action potential duration at half-amplitude was prolonged, and the slope of phase 4 depolarization was decelerated. The voltage clamp experiment revealed that cibenzoline (7-30 microM) depressed the slow inward current, the time-dependent potassium outward current and the hyperpolarization activated current. Neither the kinetic variable of the time-dependent potassium outward current nor the decay time of the outward current tail was altered by the drug perfusion. The results suggest that cibenzoline exerts a depressant effect on the electrical activity of sinoatrial node cells and that the depression of the currents induced by cibenzoline is due to a reduction in conductances of the current systems.
采用传统微电极和双微电极电压钳方法，研究了西苯唑啉（0.1 - 30微摩尔）对兔窦房结细胞膜电位和电流的影响。西苯唑啉以剂量依赖性方式降低心率、最大上升速率和动作电位幅度。同时，动作电位半幅持续时间延长，4期去极化斜率减慢。电压钳实验表明，西苯唑啉（7 - 30微摩尔）抑制慢内向电流、时间依赖性钾外向电流和超极化激活电流。药物灌注未改变时间依赖性钾外向电流的动力学变量或外向电流尾电流的衰减时间。结果表明，西苯唑啉对窦房结细胞的电活动具有抑制作用，且西苯唑啉诱导的电流抑制是由于电流系统电导降低所致。
