Kotake H, Hasegawa J, Hata T, Mashiba H
J Electrocardiol. 1985 Oct;18(4):377-83. doi: 10.1016/s0022-0736(85)80020-0.
The effects of disopyramide on the membrane potentials and currents of rabbit sinus node cells were studied using the conventional microelectrode and voltage clamp methods. Disopyramide (5 and 10 micrograms/m1) produced a negative chronotropic effect, and decreased the maximum rate of depolarization, the overshoot potential and the maximum diastolic potential. The action potential duration at half-amplitude was prolonged, and the slope of diastolic depolarization was reduced. In the voltage clamp experiments, disopyramide (10 and 50 micrograms/m1) reduced the potassium outward current (IK) without changing its kinetics. Disopyramide reduced the slow inward current Isi and increased the recovery time constant of Isi. The hyperpolarization-activated current (Ih) was also decreased by the drug. From these results, it is concluded that disopyramide has a depressant effect on the electrical activity of sinus node cells by mediating depression of IK, Isi and Ih.
采用传统微电极和电压钳方法研究了丙吡胺对家兔窦房结细胞膜电位和电流的影响。丙吡胺（5和10微克/毫升）产生负性变时作用，降低最大去极化速率、超射电位和最大舒张电位。动作电位半幅持续时间延长，舒张期去极化斜率降低。在电压钳实验中，丙吡胺（10和50微克/毫升）降低外向钾电流（IK），而不改变其动力学。丙吡胺降低慢内向电流Isi并增加Isi的恢复时间常数。该药物也降低了超极化激活电流（Ih）。从这些结果得出结论，丙吡胺通过介导IK、Isi和Ih的抑制对窦房结细胞的电活动产生抑制作用。
