青蛙神经肌肉接头处递质的延迟释放。

Delayed release of transmitter at the frog neuromuscular junction.

作者信息

Rahamimoff R, Yaari Y

出版信息

J Physiol. 1973 Jan;228(1):241-57. doi: 10.1113/jphysiol.1973.sp010084.

DOI:10.1113/jphysiol.1973.sp010084

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1331238/

Abstract

After the end-plate potential (e.p.p.) there is an increase in the frequency of the miniature e.p.p.s. This delayed release of transmitter was studied at the frog neuromuscular junction, using conventional intracellular and extracellular recording techniques. E.p.p. amplitude was kept subthreshold by subnormal concentrations of activating divalent ions.2. The ratio delayed release: initial release had values between 2 and 140%, depending on the experimental conditions; it decreased with an increase in Ca concentration and quantal content.3. Delayed release is larger at low temperature than at room temperature.4. Delayed release is statistically independent of the amplitude of the preceding e.p.p.5. The time course of the decay of the delayed release is monotonic when strontium is the activating divalent ion; it shows a ;dip' in more than 50% of the cases when Ca activated release.6. The results were discussed in terms of the residual Ca ion hypothesis.

摘要

终板电位（e.p.p.）出现后，微小终板电位（miniature e.p.p.s）的频率会增加。利用传统的细胞内和细胞外记录技术，在青蛙神经肌肉接头处对这种递质的延迟释放进行了研究。通过低于正常浓度的激活二价离子使终板电位幅度保持在阈值以下。
延迟释放与初始释放的比值在2%至140%之间，具体取决于实验条件；它随钙离子浓度和量子含量的增加而降低。
低温时的延迟释放比室温时更大。
延迟释放与前一个终板电位的幅度在统计学上无关。
当锶作为激活二价离子时，延迟释放衰减的时间进程是单调的；当钙激活释放时，在超过50%的情况下会出现一个“低谷”。
根据残余钙离子假说对结果进行了讨论。