Synaptic vesicle pools and vesicle recycling in nerve terminals

神经末梢的突触小泡池和小泡回收

基本信息

批准号：
10680760
负责人：
KUROMI Hiroshi
金额：
$ 2.18万
依托单位：
Gunma University, School of Medicine, Institute for Behavioral Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680760/
关键词：
synaptic vesicles FM1-43 exo endo cycling pool reserve pool stimulation frequency cAMP PKA cascade rutabaga dunce quantal content forskolin cyclosporin A

项目摘要

In a temperature-sensitive Drosophila mutant, shibire, synaptic vesicles are completely depleted in nerve terminals after stimulation at 34゜C, but upon returning to 22゜C endocytosis resumes. In this study synaptic vesicles in the boutons of nerve terminals at the mutant neuromuscular junction were loaded with a fluorescent dye, FM1-43, during vesicle reformation at 22゜C after complete depletion at 34゜C. We found two distinct pools of synaptic vesicles, namely an exo/endo cycling pool, located in the periphery of the bouton and a reserve pool, located in its center. Cytochalasin D treatment eliminated the reserve pool and reduced synaptic transmission evoked by high frequency stimulation. Thus the reserve pool may play a crucial role for sustaining high frequency synaptic transmission. To determine the role of exo/endo cycling vesicle pool in synaptic transmission, we estimated the quantal content electrophysiologically while the pool size was determined optically using fluorescent dye … More FM1-43. We then manipulated the size of the pool with following treatments. First, to change the state of boutons of terminals motoneuronal axons were severed. With this treatment the size of exo/endo cycling vesicle pool decreased together with the quantal content. Secondly, we promoted the FM1-43 uptake using cyclosporin A which inhibits calcineurin activities and enhances endocytosis. Cyclosporin A increased the total uptake of FM1-43, but neither the size of exo/endo cycling vesicle pool nor the quantal content changed . Thirdly, we increased the size of exo/endo cycling vesicle pool by forskolin which enhances synaptic transmission. The forskolin-treatment increased both the size of exo/endo cycling vesicle pool and the quantal content. Thus, we found that the quantal content was closely correlated with the size of exo/endo cycling vesicle pool but not necessarily with the total uptake of FM1-43 fluorescence by boutons. The results suggest that vesicles in the exo/endo cycling pool primarily participate in evoked exocytosis of vesicles. Less

在温度敏感的果蝇突变体中，在这项研究中，在这项研究中，在荧光染料中，在22届牛肉染料中，在22 cy c的神经肌肉连接中恢复了神经末端的突触囊泡。 . We Found Two Distinct Of Synaptic Vesict, Namely An EXO/Endo Cycling Pool, Located in the Periphery of the Bouton and a reserve pool, located in is center. Cytochalasin dtriminated the reserved Pool and Reduced Synaptic Transmission by HIGH Quency stimulation. Thus the保留的池可能在突触传播中起着至关重要的作用。终端的胸神经元进行了处理。外观/内部循环囊泡的大小或数量的变化骑自行车的囊泡池，但胸子的总吸收FM1-43表明，在Exo/endo循环池中的囊泡囊泡在诱发的囊泡中较少。