An analysis of the inhibitory post‐synaptic current in the voltage‐clamped crayfish muscle.
An analysis of the inhibitory post‐synaptic current in the voltage‐clamped crayfish muscle.
复制标题
电压钳制小龙虾肌肉中抑制性突触后电流的分析。
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
A. Takeuchi
中科院分区：
文献类型：
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作者：
K. Onodera;A. Takeuchi
1.通过纵向插入克氏螯虾（Cambarus clarkii）爪的开口肌纤维的丝状电极，从反馈电流记录抑制性突触后电流（i.p.c.s）。2. I.p.s.c.在大约3 - 4毫秒内上升到峰值，并近似指数衰减。-100 mV时的衰减时间常数为9.4 msec。3.衰减时间常数随着膜的超极化而减小，在去极化过程中增加。时间常数（tau）取决于电压（V），关系式为tau = a exp（AV），其中a = 18.6 msec，A = 0.0065 mV-1。电压依赖性的方向与在辙叉端板处观察到的方向相反，但与e.p.s.c.方向相同。在小龙虾肌肉中。4.在较低的温度下，ipscs的上升和下降时间延长。在22.6和12.5 ℃之间，衰减时间常数的Q10为2.4。5.当pH从7.2降低到5.5时，衰减时间常数增加约50%，时间过程的电压依赖性变化不大。6.当溶液中的氯化物变成碘化物时，衰减时间常数增加了3倍，而时间过程的电压依赖性没有改变。在溴化物溶液中，衰减时间常数增加约50%. 7.当膜去极化时，i.p.s.c.s的峰值幅度近似线性，但当膜超极化超过反转电位时，它们趋于平稳。非线性的I-V关系不是由电压箝位不足引起的，也不是由内部氯化物浓度变化引起的。用碘化物溶液平衡后，I-V关系近似呈线性。8.重复神经刺激后衰减时间常数增加。这种延长在较低温度下变得更加明显。9.讨论了发射机作用的动力学过程。这表明，i.p.s.c.的限速过程。是递质与受体的结合和分离。
1. Inhibitory post‐synaptic currents (i.p.c.s) were recorded from the feed‐back current through a wire electrode inserted longitudinally into the opener muscle fibre of the claw in the crayfish (Cambarus clarkii). 2. I.p.s.c. rose to its peak in about 3‐4 msec and decayed approximately exponentially. The decay time constant at ‐100 mV was 9.4 msec. 3. The decay time constant decreased as the membrane was hyperpolarized and increased during depolarization. The time constant (tau) depends on voltage (V) according to the relation tau = a exp (AV), with a = 18.6 msec and A = 0.0065 mV‐1. Voltage dependence was opposite in direction to that seen at frog end‐plates, but in the same direction as that of e.p.s.c. in crayfish muscle. 4. At lower temperatures, the rise and fall times of i.p.s.c.s were prolonged. Q10 for the decay time constant was 2.4 between 22.6 and 12.5 degrees C. 5. When pH was decreased from 7.2 to 5.5, the decay time constant increased by about 50%, with little change in the voltage dependence of the time course. 6. When chloride in the solution was changed to iodide, the decay time constant was increased by a factor of 3, while voltage dependence of the time course was not changed. In bromide solution the decay time constant increased by about 50%. 7. Peak amplitudes of i.p.s.c.s were approximately linear as the membrane was depolarized, but they levelled off as the membrane was hyperpolarized beyond reversal potential. The non‐linear I‐V relation did not result from inadequate voltage clamping, nor from a change in the inside concentration of chloride. After equilibration with iodide solution the I‐V relation was approximately linear. 8. The decay time constant was increased after repetitive nerve stimulation. This prolongation became more pronounced at lower temperatures. 9. The kinetic process of the transmitter action is discussed. It is suggested that the rate limiting process for i.p.s.c. is binding and unbinding of the transmitter to the receptor.