ACETYLCHOLINE-INDUCED MEMBRANE DEPOLARIZATION AND POTENTIAL FLUCTUATIONS IN THE RAT ADRENAL CHROMAFFIN CELL
ACETYLCHOLINE-INDUCED MEMBRANE DEPOLARIZATION AND POTENTIAL FLUCTUATIONS IN THE RAT ADRENAL CHROMAFFIN CELL
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DOI：
10.1113/jphysiol.1982.sp014107
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发表时间：
1982-01-01
影响因子：
5.5
通讯作者：
OZAWA, S
中科院分区：
文献类型：
--
作者：
KIDOKORO, Y;MIYAZAKI, S;OZAWA, S
用细胞内记录技术观察了乙酰胆碱(ACh)对培养的大鼠肾上腺嗜铬细胞膜的影响。ACh通过吸管施加气体压力，吸管的内部尖端直径为.apprx。3微米。在ACh的作用下，嗜铬细胞膜因叠加的电势波动而去极化。在ACh作用至30 S的整个过程中，偶尔可观察到重复的尖峰。在某些细胞中，在初始去极化后出现缓慢的时间进程的超极化。0.1µm-ACh可检测到去极化，幅度随ACh浓度的升高而增大，在100µm时达到饱和，半最大浓度为apprx。10微米。当通过记录电极通过电流超极化时，ACh去极化的幅度增加，并且在去极化时减小。这项技术给出了-24.+-的明显反转电势。4 mV(平均值+-。S.D.，6)。当绘制ACh去极化的平均幅度和给定单元中的电势起伏的方差时，发现了线性关系。斜率为0.23。+-。0.06 mV(9)，平均膜电位为-60 mV。在几个假设下，这个值近似于基本势能变化的幅度。通过计算自相关函数，得到了势能起伏的时间特性。给定单元的平均自相关函数随时间呈指数下降。平均时间常数为31度。C为40。+-。19 ms(9)，平均膜电位为-60 mV。通过几个假设，该值提供了基本潜在变化的平均持续时间的估计。通过改变外溶液的离子组成，探讨了ACh去极化的离子机制。在ACh去极化过程中，Na、K和Ca离子似乎是电流的载流子，而Cl离子不起作用。应用不同的ACh受体激动剂和拮抗剂来确定这些ACh受体的药理特性。受体是尼古丁的。讨论了ACh引起的膜电位波动的本质。
The effect of acetylcholine (ACh) on the rat adrenal chromaffin cell membrane was examined in culture by using an intracellular recording technique. ACh was applied with gas pressure through a pipette which had an internal tip diameter of .apprx. 3 .mu.m. Upon application of ACh the chromaffin cell membrane depolarized with superimposed potential fluctuations. Occasionally repetitive spikes were observed during the entire period of ACh application up to 30 s. In some cells a hyperpolarization with a slow time course followed the initial depolarization. The depolarization was detectable with 0.1 .mu.M-ACh; the amplitude increased with higher concentrations of ACh and saturated at 100 .mu.M. The half-maximal concentration was .apprx. 10 .mu.M. The amplitude of the ACh depolarization increased when the membrane was hyperpolarized by passing current through the recording electrode, and decreased upon depolarization. This technique gave an apparent reversal potential of -24 .+-. 4 mV (mean .+-. S.D., 6). When the mean amplitude of the ACh depolarizations and the variance of the potential fluctuations in a given cell were plotted, a linear relation was found. The slope was 0.23 .+-. 0.06 mV (9) at the average membrane potential level of -60 mV. With a few assumptions this value approximates the amplitude of an elementary potential change. Temporal characteristics of the potential fluctuations were obtained by calculating an auto-correlation function. The average auto-correlation function in a given cell declined exponentially with time. The mean time constant at 31.degree. C was 40 .+-. 19 ms (9) at the average membrane potential level of -60 mV. With a few assumptions this value provides an estimate of the mean duration of an elementary potential change. The ionic mechanism of the ACh depolarization was examined by changing the ion composition of the external solution. Na, K and Ca ions appear to be the current carriers during the ACh depolarization; Cl ions do not contribute. Various ACh receptor agonists and antagonists were applied to determine the pharmacological properties of these ACh receptors. The receptors were nicotinic. The nature of the ACh-induced membrane potential fluctuations is discussed.