Li X J, Fan J S, Liu Y W, Zhang B H
Department of Pharmacology, Beijing Medical University.
Yao Xue Xue Bao. 1993;28(2):81-4.
The electrophysiological effects of PTS in sheep cardiac Purkinje fibers were studied. PTS was shown to increase the duration of action potential (APD30, APD50 and APD90) at the concentrations of 2.5 micrograms/ml and 5.0 micrograms/ml. However, the amplitude of action potential (APA) remained unchanged. The result of using double microelectrode voltage clamp method showed that PTS (1.25-10.0 micrograms/ml) depressed the delayed (outward) rectifier current (Ix) in time- and dose-dependent manners, when the holding potential was held at +20 mV, the command potential was held at +10 mV, 0.2 Hz and the clamping time at 1-1.5 s. It may be concluded that the effect of PTS on APD is mainly related to blocking the delayed rectifier potassium channel.
研究了PTS对绵羊心脏浦肯野纤维的电生理效应。结果表明，在2.5微克/毫升和5.0微克/毫升的浓度下，PTS可增加动作电位时程（APD30、APD50和APD90）。然而，动作电位幅度（APA）保持不变。采用双微电极电压钳法的结果显示，当钳制电位保持在+20 mV，指令电位保持在+10 mV，频率为0.2 Hz，钳制时间为1 - 1.5 s时，PTS（1.25 - 10.0微克/毫升）以时间和剂量依赖的方式抑制延迟（外向）整流电流（Ix）。可以得出结论，PTS对APD的影响主要与阻断延迟整流钾通道有关。
