ROLE OF CALCIUM IN NEUROMUSCULAR FACILITATION
ROLE OF CALCIUM IN NEUROMUSCULAR FACILITATION
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DOI：
10.1113/jphysiol.1968.sp008469
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发表时间：
1968-01-01
影响因子：
5.5
通讯作者：
MILEDI, R
中科院分区：
文献类型：
--
作者：
KATZ, B;MILEDI, R
提出了一个假说，即在神经冲动过程中进入终末轴突膜的活性钙的残留物是短期易化的原因。通过改变局部Ca浓度在肌神经接头上测试该暗示，使得在2个神经冲动中的第一个神经冲动期间[Ca]0远低于第二个冲动期间的[Ca]0，或者升高到接近第二个冲动期间的水平。在后一种情况下，促进作用要大得多，这与“Ca假说”一致。一个短脉冲的去极化集中应用于结之后是一个短暂的时期非常强烈的促进。这可以在河豚毒素处理的制剂中看到，例如通过将去极化从1毫秒延长至2毫秒。这会导致发射器释放增加50倍以上。这种大的“早期易化”（推测也发生在正常动作电位过程中）与“钙假说”有关。
The hypothesis is put forward that a residue of the ''active Ca'' which enters the terminal axon membrane during the nerve impulse is responsible for short-term facilitation. This suggestion was tested on the myoneural junction by varying the local Ca concentration so that during the first of 2 nerve impulses [Ca]0 is either much lower than, or raised to a level approaching that, during the 2nd impulse. Facilitation is much larger in the latter case, which is in accordance with the ''Ca hypothesis''. A short pulse of depolarization focally applied to the junction is followed by a brief period of very intense facilitation. This can be seen in the tetordotoxin-treated preparation, e.g. by lengthening the depolarization from 1 to 2 msec. which can cause a more than 50-fold increase in transmitter release. This large ''early facilitation'' (which presumably occurs also during the course of a normal action potential) is discussed in relation to the ''Ca hypothesis''.