Satoh H, Hashimoto K
Eur J Pharmacol. 1984 Mar 23;99(2-3):185-91. doi: 10.1016/0014-2999(84)90240-1.
The effects of propafenone (1-50 micrograms/ml) on the membrane potential and currents of the rabbit sino-atrial node were studied using the voltage clamp technique. Propafenone decreased the heart rate, amplitude of the action potential and maximum rate of depolarization. It also depolarized the maximum diastolic potential and the resting potential and prolonged the action potential duration dose dependently. On the current systems of the sino-atrial node, propafenone reduced the outward current (ik), the inward current activated by hyperpolarization (ih) and the slow inward current (is) dose dependently. The decrease in is and ik by propafenone was due to the reductions in their conductance, not to the changes in the voltage dependence of the inactivation of is or activation of ik. The decrease in ik might be the ionic mechanism of the negative chronotropic effect of propafenone.
采用电压钳技术研究了普罗帕酮（1 - 50微克/毫升）对家兔窦房结膜电位和电流的影响。普罗帕酮降低心率、动作电位幅度和最大去极化速率。它还使最大舒张电位和静息电位去极化，并剂量依赖性地延长动作电位时程。在窦房结的电流系统上，普罗帕酮剂量依赖性地降低外向电流（ik）、超极化激活的内向电流（ih）和慢内向电流（is）。普罗帕酮使is和ik降低是由于其电导降低，而非is失活或ik激活的电压依赖性改变。ik降低可能是普罗帕酮负性变时作用的离子机制。
