Giebisch G, Weidmann S
J Gen Physiol. 1971 Mar;57(3):290-6. doi: 10.1085/jgp.57.3.290.
Bundles of sheep ventricular fibers were voltage-clamped utilizing a modified sucrose gap technique and intracellular voltage control. An action potential was fired off in the usual way, and the clamp circuit was switched on at preselected times during activity. Clamping the membrane back to its resting potential during the early part of an action potential resulted in a surge of inward current. The initial amplitude of this current surge decreased as the clamp was switched on progressively later during the action potential. Inward current decreasing as a function of time was also recorded if the membrane potential was clamped beyond the presumed K equilibrium potential (to -130 mv). Clamping the membrane to the inside positive range (+40 mv to +60 mv) at different times of an action potential resulted in a step of outward current which was not time-dependent. The results suggest that normal repolarization of sheep ventricle depends on a time-dependent decrease of inward current (Na, Ca) rather than on a time-dependent increase of outward current (K).
采用改良的蔗糖间隙技术和细胞内电压控制方法对绵羊心室纤维束进行电压钳制。以常规方式激发动作电位，并在活动期间的预先选定时间开启钳制电路。在动作电位的早期将膜钳制回到其静息电位会导致内向电流激增。随着在动作电位期间钳制开启时间逐渐延迟，该电流激增的初始幅度会降低。如果将膜电位钳制到超过假定的钾平衡电位（至 -130 mV），也会记录到内向电流随时间下降的情况。在动作电位的不同时间将膜钳制到膜内正向范围（+40 mV 至 +60 mV）会导致一个与时间无关的外向电流阶跃。结果表明，绵羊心室的正常复极化取决于内向电流（钠、钙）随时间的减少，而不是外向电流（钾）随时间的增加。
