Study of auditory hair cells with patch clamp method

采用木瓜蛋白酶处理金鱼的听觉器官（囊），获得单个毛细胞，并用膜片钳法进行研究。在全细胞电压钳下记录感应毛弯曲时的传导电流。目前只有8次录音成功。技术改进正在进行中。在全细胞电流钳下记录膜电位。对方电流注入观察到两种类型的响应。一种是膜电位在50 ~ 200 Hz的振荡变化，见于囊状黄斑吻侧丰富的卵形或短圆柱形细胞。另一种是缓慢去极化和动作电位，主要分布在尾部的细长细胞中。在外部溶液中存在阻滞剂和/或不同离子组成的情况下，用电压钳法检测膜电流。确定了Ca电流、Ca激活K电流、a电流和内向整流K电流。此外，观察到瞬态内向电流，可能是Na电流。在内向外模式下研究了钙活化钾通道（BK通道）的单通道特性。它们的单一电导为150 ~ 300ps，对k具有选择性通透性。与染色质细胞膜上的类似通道相比，在5 M的Ca浓度下测量的平方电压阶的响应时间过程非常快。

The auditory organ of goldfish (saccule) was excised and individual hair cells were obtained by papain treatment and studied with patch clamp method.1. Transduction currents, i.e. currents responding to bending of the sensory hairs were recorded under whole-cell voltage clamp. Only eight recordings were successful yet. Technical improvements are now going on.2. Membrane potential was recorded under whole-cell current clamp. Two types of responses were observed to the square current injection. One is oscillatory change of membrane potential from 50 to 200 Hz, which was seen in ovoid or short cylindrical cells abundant in the rostral part of the saccular macula. The other is slow depolarization and action potential, which was seen in long slender cells abundant in the caudal part.3. Membrane currents were examined with voltage-clamp method under the presence of blockers and/or different ionic composition of the external solution. Ca current, Ca-activate K current, A-current, and inwardly rectifying K current were identified. In addition, transient inward current, probably Na current, was observed.4. Single channel characteristics of Ca-activated K channels (BK channels) were studied under inside-out mode. Their unitary conductance was 150 to 300 ps and it had selective permeability to K. Time course of the response to square voltage steps, measured with internal Ca concentration o 5 M was very fast as compared with similar channels in the chromaffin cell membrane.