The inhibition of sodium currents in myelinated nerve by quaternary derivatives of lidocaine.
The inhibition of sodium currents in myelinated nerve by quaternary derivatives of lidocaine.
复制标题
DOI：
10.1085/jgp.62.1.37
复制
发表时间：
1973-07
影响因子：
3.8
通讯作者：
Strichartz, G R
中科院分区：
文献类型：
--
作者：
Strichartz, G R
研究了利多卡因季衍生物对单髓神经纤维钠电流的抑制作用。外用季元利多卡因（QX）对膜电流影响不大。存在于轴质（<0.5 mM）的QX对钠电流的抑制作用超过90%。抑制发生在恒定的强直相位和可变的电压敏感相位的总和。当钠离子通道打开时，膜电位模式会产生大的去极化，这有利于电压敏感抑制。电压敏感抑制可以通过打开钠通道的小的去极化来逆转。对这一观察结果的一种解释是，QX分子从轴浆侧进入开放的钠通道，并在通道内结合。QX抑制的电压依赖性表明，药物结合在从钠通道内部到外部的电梯度大约一半的位置。
The inhibition of sodium currents by quaternary derivatives of lidocaine was studied in single myelinated nerve fibers. Membrane currents were diminished little by external quaternary lidocaine (QX). QX present in the axoplasm (<0.5 mM) inhibited sodium currents by more than 90%. Inhibition occurred as the sum of a constant, tonic phase and a variable, voltage-sensitive phase. The voltage-sensitive inhibition was favored by the application of membrane potential patterns which produce large depolarizations when sodium channels are open. Voltage-sensitive inhibition could be reversed by small depolarizations which opened sodium channels. One explanation of this observation is that QX molecules enter open sodium channels from the axoplasmic side and bind within the channels. The voltage dependence of the inhibition by QX suggests that the drug binds at a site which is about halfway down the electrical gradient from inside to outside of the sodium channel.