Local anaesthetics transiently block currents through single acetylcholine‐receptor channels.
Local anaesthetics transiently block currents through single acetylcholine‐receptor channels.
复制标题
局部麻醉剂暂时阻断通过单个乙酰胆碱受体通道的电流。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
J. Steinbach
中科院分区：
文献类型：
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作者：
E. Neher;J. Steinbach
1.在慢性失神经支配的蛙肌连接外膜上，记录到通过乙酰胆碱受体通道(ACh通道)的单通道电流。2.由于单个ACh通道的开放和关闭(由琥珀胆碱激活)引起的电流波形通常是方波。当药物QX-222在激动剂之外存在时，这些单个脉冲似乎被砍成短得多的脉冲。3.阵发性发作的平均持续时间与正常通道开放时间相当或更长，并随药物浓度的增加而增加。4.短脉冲的持续时间随药物浓度的增加而减小。5.结果表明，药物分子可逆地阻塞开放的终板通道，而猝发中的闪烁代表了这种快速、重复发生的反应。6.反应速率的电压依赖关系表明，封闭反应的位置在膜的中心，可能在离子通道内。
1. Single channel currents through acetylcholine receptor channels (ACh channels) were recorded at chronically denervated frog muscle extrajunctional membranes in the absence and presence of the lidocaine derivatives QX‐222 and QX‐314. 2. The current wave forms due to the opening and closing of single ACh channels (activated by suberyldicholine) normally are square pulses. These single pulses appear to be chopped into bursts of much shorter pulses, when the drug QX‐222 is present in addition to the agonist. 3. The mean duration of the bursts is comparable to or longer than the normal channel open time, and increases with increasing drug concentration. 4. The duration of the short pulses within a burst decreases with increasing drug concentration. 5. It is concluded that drug molecules reversibly block open end‐plate channels and that the flickering within a burst represents this fast, repeatedly occurring reaction. 6. The voltage dependence of the reaction rates involved, suggested that the site of the blocking reaction is in the centre of the membrane, probably inside the ionic channel.