Levi R, DeFelice L J
Biophys J. 1986 Jul;50(1):5-9. doi: 10.1016/S0006-3495(86)83433-6.
With no Ca in the patch electrode, two kinds of channels conduct Na in spontaneously beating embryonic chick heart cells. One channel conducts Na primarily during the upstroke of the action potential and is blocked by tetrodotoxin (TTX). The other channel conducts Na primarily during the late plateau and early repolarization phase of the action potential, but only in Ca concentrations below 10(-6) M. This second channel is TTX-insensitive and has a conductance of 50 to 90 pS, depending upon the interpretation of open-channel flickering. These two Na-conducting channels correspond to the channels that normally carry the fast Na current (INa) and the slow Ca current (Isi).
在膜片钳电极中无钙离子的情况下，两种通道在自发搏动的鸡胚心脏细胞中传导钠离子。一种通道主要在动作电位的上升支期间传导钠离子，并且被河豚毒素（TTX）阻断。另一种通道主要在动作电位的晚期平台期和早期复极化阶段传导钠离子，但仅在钙离子浓度低于10^(-6) M时。第二种通道对TTX不敏感，并且电导为50至90 pS，这取决于对开放通道闪烁的解释。这两种钠传导通道分别对应于正常情况下携带快速钠电流（INa）和缓慢钙电流（Isi）的通道。
