Interaction of tetramethrin and deltamethrin at the single sodium channel in rat hippocampal neurons
Interaction of tetramethrin and deltamethrin at the single sodium channel in rat hippocampal neurons
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DOI：
10.1016/s0161-813x(01)00023-7
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发表时间：
2001-06-01
期刊：
影响因子：
3.4
通讯作者：
Narahashi, T
中科院分区：
文献类型：
--
作者：
Motomura, H;Narahashi, T
已知I型和II型拟除虫菊酯能调节钠通道，在去极化和复极化时引起持续性开放。尽管两种拟除虫菊酯对钠通道的作用有一些相似之处，但两种拟除虫菊酯对钠电流的修饰方式不同。本研究采用膜片钳技术，研究了拟除虫菊酯类杀虫剂对大鼠海马神经元钠通道的作用。溴氰菊酯修饰的钠通道开放的时间比四氯氰菊酯修饰的钠通道长得多。将10微米的溴氰菊酯应用于暴露于10微米溴氰菊酯的膜片上，溴氰菊酯修饰的延长的单钠电流消失，取而代之的是较短的开放，这是菊酯修饰的通道开放的特征。这些单通道数据与以前关于I型和II型拟除虫菊酯之间的全细胞竞争研究是一致的。这些结果被解释为由于第I型拟除虫菊酯分子从同一结合部位取代了第II型拟除虫菊酯分子，或由于两个拟除虫菊酯分子作为单独的钠通道位点而发生变构相互作用。(C)2001 Elsevier Science Inc.保留所有权利。
Type I and type II pyrethroids are known to modulate the sodium channel to cause persistent openings during depolarization and upon repolarization. Although there are some similarities between the two types of pyrethroids in their actions on sodium channels, the pattern of modification of sodium currents is different between the two types of pyrethroids. In the present study, interactions of the type I pyrethroid tetramethrin and the type II pyrethroid deltamethrin at rat hippocampal neuron sodium channels were investigated using the inside-out single-channel patch clamp technique. Deltamertrin-modified sodium channels opened much longer than tetramethrin-modified sodium channels. When 10 muM tetramethrin was applied to membrane patches that had been exposed to 10 muM deltamethrin, deltamertrin-modified prolonged single sodium currents disappeared and were replaced by shorter openings which were characteristic of tetramethrin-modified channel openings. These single-channel data are compatible with previous whole-cell competition study between type I and type II pyrethroids. These results are interpreted as being due to the displacement of the type II pyrethroid molecule by the type I pyrethroid molecule from the same binding site or to the allosteric interaction of the two pyrethroid molecules as separate sodium channel sites. (C) 2001 Elsevier Science Inc. All rights reserved.