THE EFFECT OF LOCAL-ANESTHETICS ON THE COMPONENTS OF THE ASYMMETRY CURRENT IN THE SQUID GIANT-AXON
THE EFFECT OF LOCAL-ANESTHETICS ON THE COMPONENTS OF THE ASYMMETRY CURRENT IN THE SQUID GIANT-AXON
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DOI：
10.1113/jphysiol.1984.sp015315
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发表时间：
1984-01-01
影响因子：
5.5
通讯作者：
NEUMCKE, B
中科院分区：
文献类型：
--
作者：
BEKKERS, JM;GREEFF, NG;NEUMCKE, B
研究了局部麻醉药和保持电位对细胞内透析的鱿鱼巨轴突钠电流和不对称电流的影响。将非对称电流分为灭活分量和非灭活分量，在-20 ~ +40 mV脉冲电位范围内测定两分量的电荷位移Qi和Qn。带电荷的局麻药rad366是利多卡因的四元衍生物，在透析液中以1mm的浓度内服，没有改变Qn，但使Qi降低了约3倍。中性局麻药苯佐卡因，外用浓度为1mm的沐浴液，其效果与RAD 366非常相似。它没有改变Qn，但减少了气和Na电流约2.5倍。与局麻药不同，稳定的膜去极化对Qn、Qi和Na电流的影响基本相同。将保持电位从-98 mV降低到-60 mV几分钟后，所有3个变量都减少了一半左右。讨论了钠通道电压门控模型，该模型涉及Qn和Qi，并解释了Na失活和局部麻醉剂对Qi的选择性阻断。
The effects of local anesthetics and holding potential on Na and asymmetry currents were studied in intracellularly dialyzed squid giant axons. The asymmetry currents were fractionated into their inactivating and non-inactivating components, and the charge displacements Qi and Qn of the 2 components were determined for pulse potentials between -20 and +40 mV. The charged local anesthetic RAD 366, a quaternary derivative of lidocaine, applied internally at a concentration in the dialysis solution of 1 mM, did not change Qn, but reduced Qi about 3-fold. The neutral local anesthetic benzocaine, applied externally at a concentration in the bathing solution of 1 mM, had effects very similar to RAD 366. It did not change Qn, but reduced Qi and the Na current about 2.5-fold. Unlike local anesthetics, steady membrane depolarization had essentially equal effects on Qn, Qi and Na current. Lowering the holding potential from -98 to -60 mV for several minutes reduced all 3 variables to about half. Models of Na channel voltage-gating are discussed which implicate both Qn and Qi, and which account for the selective blockage of Qi by Na inactivation and local anesthetics.