Study of auditory hair cells with patch clamp method

取金鱼听器（球囊），经木瓜蛋白酶处理后分离单个毛细胞，用膜片钳技术进行研究.在全细胞电压钳下记录转导电流，即响应于感觉毛弯曲的电流。目前，只有8次录制成功。现在正在进行技术改进.在全细胞电流钳下记录膜电位。两种类型的响应被观察到的平方电流注入。一种是膜电位在50 ~ 200 Hz范围内的振荡变化，见于囊斑吻部丰富的卵圆形或短圆柱形细胞。另一种是慢去极化和动作电位，见于尾侧部丰富的细长细胞.在阻断剂和/或不同离子组成的外溶液存在下，用电压钳法检测膜电流。钙电流、钙激活钾电流、A电流和内向整流钾电流。此外，还观察到瞬时内向电流，可能是钠电流.在由内而外的模式下研究了钙激活钾通道（BK通道）的单通道特性。它们的单位电导率为150 ~ 300 ps，对K具有选择性渗透性。与嗜铬细胞膜中的类似通道相比，用内部Ca浓度o 5 M测量的对平方电压阶跃的响应的时间过程是非常快的。

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.