Ca2+-dependent recycling of synaptic vesicles at the frog neuromuscular junction.
Ca2+-dependent recycling of synaptic vesicles at the frog neuromuscular junction.
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DOI：
10.1083/jcb.87.1.297
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发表时间：
1980-10
影响因子：
7.8
通讯作者：
Hurlbut, W P
中科院分区：
文献类型：
--
作者：
Ceccarelli, B;Hurlbut, W P
用低剂量的黑寡妇蛛毒粗品（BWSV）或纯化的α-latrotoxin处理蛙胸皮肌，研究了神经肌肉传递、量子分泌、超微结构和辣根过氧化物酶（HRP）摄取的变化。当将这些药物应用于浸泡在含有1 mM EGTA和4 mM Mg 2+的无Ca 2+溶液中的肌肉时，量子分泌速率升至高水平，但很快消退;神经肌肉传递在1小时内被完全且不可逆地阻断。终末肿胀，囊泡耗尽; HRP未被吸收。当将BWSV应用于浸泡在1.8 mM Ca 2+和4 mM Mg 2+溶液中的其他肌肉时，分泌速率上升到高水平，然后下降到中等水平，并持续整个暴露小时。神经肌肉传递在不到50%的这些纤维中被阻断。这些终末的超微结构正常，含有大量的突触小泡。如果HRP已经存在，大多数突触囊泡被标记的反应产物。这些观察结果表明，钙离子在蛙神经肌肉接头的内吞作用中起着重要的作用。
Frog cutaneous pectoris muscles were treated with low doses of crude black widow spider venom (BWSV) or purified alpha-latrotoxin, and neuromuscular transmission, quantal secretion, changes in ultrastructure and uptake of horseradish peroxidase (HRP) were studied. When these agents were applied to muscles bathed in a Ca2+-free solution with 1 mM EGTA and 4 mM Mg2+, the rate of quantal secretion rose to high levels but quickly subsided; neuromuscular transmission was totally and irreversibly blocked within 1 h. The terminals became swollen and were depleted of vesicles; HRP was not taken up. When BWSV was applied to other muscles bathed in a solution with 1.8 mM Ca2+ and 4 mM Mg2+, the rate of secretion rose to high levels and then declined to intermediate levels that were sustained throughot the hour of exposure. Neuromuscular transmission was blocked in fewer than 50% of these fibers. The ultrastructure of these terminals was normal and they contained large numbers of synaptic vesicles. If HRP had been present, most of the synaptic vesicles were labeled with reaction product. These observations suggest that Ca2+ plays an important role in endocytosis at the frog neuromuscular junction.