乙酰胆碱对豚鼠外毛细胞的电压依赖性外向整流钾电流的影响

Effects of ACh on Voltage-dependent Outwardly Rectifying Potassium Currents in Isolated Outer Hair Cells in Cochlea of Guinea Pig

杨军;汪吉宝

1:上海第二医科大学附属仁济医院耳鼻咽喉-头颈外科

2:华中科技大学同济医学院附属协和医院耳鼻咽喉科上海200001

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摘要

目的观察乙酰胆碱（ＡＣｈ）对不同长度豚鼠耳蜗外毛细胞（ＯＨＣ）电压依赖性外向整流钾电流的影响，分析ＡＣｈ对钾电流激活动力学的影响。方法全细胞膜片钳技术。结果１００μｍｏｌ／Ｌ的ＡＣｈ对短ＯＨＣ电压依赖性外向整流钾电流的影响较大，刺激电压为５０ｍＶ时，最大外向电流的幅度增加了３４．８％。ＡＣｈ对峰电流的影响大于稳态电流，改变了外向整流钾电流的动力学特征。ＡＣｈ将ＯＨＣ的零电流电位向超极化方向移位约５ｍＶ。1００μｍｏｌ／Ｌ的ＡＣｈ使ＯＨＣ电压依赖性外向整流钾电流的激活动力学发生改变，Ｖ（１／２）＝（－５２．３８±３．９８）ｍＶ，较作用前明显超极化，激活的电压敏感性也提高，Ｓ＝（４０±４．１４）ｍＶ（ｎ＝５）。结论ＡＣｈ增加了ＯＨＣ电压依赖性外向整流钾通道的电导，使通道的激活电压向超极化方向移位。ＡＣｈ的作用是使ＯＨＣ超极化。

关键词

外毛细胞;乙酰胆碱;外向整流钾电流;超极化;激活动力学

基金项目(Foundation):

作者

杨军;汪吉宝

参考文献

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外毛细胞乙酰胆碱外向整流钾电流超极化激活动力学

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杨军汪吉宝