Turnover of transmitter and synaptic vesicles at the frog neuromuscular junction.
Turnover of transmitter and synaptic vesicles at the frog neuromuscular junction.
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DOI：
10.1083/jcb.57.2.499
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发表时间：
1973-05
期刊：
影响因子：
--
通讯作者：
Mauro A
中科院分区：
文献类型：
--
作者：
Ceccarelli B;Hurlbut WP;Mauro A
以10/s或2/s的速度刺激青蛙的弯曲胸皮神经肌肉，刺激时间为20分钟至4小时。细胞内记录终板电位，并用于估计刺激期间分泌的递质量。在刺激期结束时，将这些制剂固定在电子显微镜下或用黑寡妇蜘蛛毒液处理，以确定末端遗留的递质数量。将辣根过氧化物酶或右旋糖酐添加到沐浴液中，并用作示踪剂来检测腋膜中囊泡的形成。在以2/s的速度刺激4 h时，腋膜形成了许多新的囊泡，分泌的递质数量比初始储存的数量多出数倍。在这段时间的刺激后，末梢的递质严重减少，但囊泡没有减少，其一般形态组织正常。在以10/s的速度刺激20分钟时，神经末梢肿胀，囊泡和递质严重衰竭。在随后的一个小时的休息中，形态学的变化在很大程度上被逆转，许多新的小泡从腋膜形成，部分的递质储存得到补充。这些结果表明：(a)突触囊泡在刺激期间和刺激后与神经末梢膜融合并重新形成；(b)重新形成的囊泡可以储存和释放递质。
Curarized cutaneous pectoris nerve-muscle preparations from frogs were stimulated at 10/s or at 2/s for periods ranging from 20 min to 4 h. End plate potential were recorded intracellularly and used to estimate the quantity of transmitter secreted during the period of stimulation. At the ends of the periods of stimulation the preparations were either fixed for electron microscopy or treated with black widow spider venom to determine the quantities of transmitter remainind in the terminal. Horseradish peroxidase or dextran was added to the bathing solution and used as a tracer to detect the formation of vesicles from the axolemma. During 4 h of stimulation at 2/s many new vesicles were formed from the axolemma and the quantity of transmitter secreted was several times greater than the quantity in the initial store. After this period of stimulation, the terminals were severely depleted of transmitter, but not of vesicles, and their general morphological organization was normal. During 20 min of stimulation at 10/s the nerve terminals swelled and were severely depleted both of vesicles and of transmitter. During a subsequent hour of rest the changes in morphology were largely reversed, many new vesicles were formed from the axolemma and the stores of transmitter were partially replenished. These results suggest (a) that synaptic vesicles fuse with, and re-form from, the membrane of the nerve terminal during and after stimulation and (b), that the re-formed vesicles can store and release transmitter.