MULTIPLE CONDUCTANCE STATES OF SINGLE ACETYLCHOLINE-RECEPTOR CHANNELS IN EMBRYONIC MUSCLE-CELLS
MULTIPLE CONDUCTANCE STATES OF SINGLE ACETYLCHOLINE-RECEPTOR CHANNELS IN EMBRYONIC MUSCLE-CELLS
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DOI：
10.1038/294462a0
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发表时间：
1981-01-01
期刊：
影响因子：
64.8
通讯作者：
SAKMANN, B
中科院分区：
文献类型：
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作者：
HAMILL, OP;SAKMANN, B
乙酰胆碱（ACh）激活骨骼肌突触膜中由许多基本电流组成的内向电流1，2。在成年青蛙肌肉中的高分辨率电流测量表明，基元电流是单位振幅的脉冲状事件，表明ACh打开只有两种电导状态的离子通道，完全打开或关闭3。我们现在提出第三种导电状态的证据。在非神经支配的胚胎大鼠肌肉的膜中，我们观察到，乙酰胆碱激活两个独立的类电流的不同幅度和平均持续时间，显然产生于两个群体的乙酰胆碱受体（AChR）通道。从这两个类的电流显示，在低发病率，一个主水平和一个子水平的较低的振幅之间的过渡。从这一点，我们得出结论，AChR通道在胚胎肌肉中采用，除了一个“主”的电导状态，一个“子状态”较低的电导。
Acetylcholine (ACh) activates in the synaptic membrane of skeletal muscle an inward current composed of many elementary currents1,2. High resolution current measurements in adult frog muscle have shown that the elementary current is a pulse-like event of unit amplitude, indicating that ACh opens ion channels which have only two conductance states, fully open or closed3. We now present evidence for a third conductance state. In the membrane of uninnervated embryonic rat muscle we observe that ACh activates two independent classes of currents of different amplitude and average duration, apparently arising from two populations of ACh receptor (AChR) channels. The currents from both classes show, at low incidence, transitions between a main level and a sublevel of lower amplitude. From this we conclude that AChR channels in embryonic muscle adopt, in addition to a ‘main’ conductance state, a ‘substate’ of lower conductance.