Single-channel current/voltage relationships of two kinds of Na+ channel in vertebrate sensory neurons.
Single-channel current/voltage relationships of two kinds of Na+ channel in vertebrate sensory neurons.
复制标题
脊椎动物感觉神经元中两种Na通道的单通道电流/电压关系。
DOI：
10.1007/bf00374946
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Campbell,DT
中科院分区：
文献类型：
--
作者：
Campbell,DT
The electrical signals of nerve and muscle are fundamentally dependent on the voltage-gated Na+channel, which is responsible for the rising phase of the action potential. At least two kinds of Na+channel are expressed in the membrane of frog dorsal root ganglion (DRG) cells: Na+channels with fast kinetics that are blocked by tetrodotoxin (TTX) at high affinity, and Na+channels with slower kinetics that are insensitive to TTX. Recordings of single-channel currents from frog DRG cells, under conditions favoring Na+as the charge carrier, reveal two distinct amplitudes of single-channel events. With 300 mM external Na+, single-channel events that can be measured in the presence of 1 μM TTX have a slope conductance 7.5 pS. In the absence of TTX, events with a slope conductance of 14.9 pS dominate. Ensemble averages of the smaller single-channel events display the slower kinetics characteristic of the macroscopic TTX-insensitive Na+currents, and ensemble averages of the larger events display the faster kinetics characteristic of the TTX-sensitive currents. The results are consistent with the idea that the toxin-binding site is sufficiently close to the pore to influence ion permeation.
