Synaptic vesicle pools and vesicle recycling in nerve terminals

神经末梢的突触小泡池和小泡回收

• 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

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Shibire中，在34゜C刺激后，神经末梢中的突触小泡完全耗尽，但当回到22゜C时，内吞作用恢复。在本研究中，突触小泡位于突变型神经肌肉接头的神经末梢周围，在34゜C完全耗尽后，在22゜C的囊泡重塑过程中，用荧光染料fm1-43标记突触小泡。我们发现两个不同的突触小泡池，即位于突触周围的外周/内向循环池和位于中央的备用池。细胞松弛素D处理消除了储备池，减少了高频刺激引起的突触传递。因此，储备池可能在维持高频突触传递方面发挥关键作用。为了确定外/内循环囊泡池在突触传递中的作用，我们用电生理学方法估计了囊泡池的量子含量，同时使用荧光染料…用光学方法确定了囊泡池的大小更多的FM1-43。然后，我们通过以下处理来控制池子的大小。首先，为了改变终末运动神经元突起的状态，切断了运动神经元轴突。经此处理后，内外循环囊泡池的大小随量子含量的减少而减小。其次，我们使用环孢菌素A促进FM1-43的摄取，环孢素A抑制钙调神经磷酸酶活性并增强内吞作用。环孢素A可增加细胞对FM1-43的摄取，但不影响内外循环囊泡池的大小和量子含量。第三，我们利用Forsklin增加了外/内循环囊泡池的大小，从而增强了突触传递。Forsklin处理增加了内外循环囊泡池的大小和量子含量。因此，我们发现量子含量与外/内循环囊泡池的大小密切相关，但不一定与Boutons对FM1-43荧光的总摄取有关。结果表明，外源/内源循环池中的囊泡主要参与囊泡的诱发性胞吐作用。较少

项目成果

Zhang,D,Kuromi,H.and Kibokoro,Y.: "Activation of metabotropic receptors enhances synaptic transmission at the Drosophila neuromuscular junction"Neuropharmacol.. 38. 645-657 (1999)

张，D，Kuromi，H. 和 Kibokoro，Y.：“代谢型受体的激活增强果蝇神经肌肉接头处的突触传递”Neuropharmacol.. 38. 645-657 (1999)

Rheuben, M.B., Yoshihara, M. and Kidokoro, Y.: "Ultrastructural correlations of neuromuscular junction development."Intern. Rev. Neurobiol.. 43. 69-9 (1999)

Rheuben, M.B.、Yoshihara, M. 和 Kidokoro, Y.：“神经肌肉接头发育的超微结构相关性。”实习生。

Yoshihara,M.,Ueda,A.,Zhang,D.,Deitcher.D.L.Schwarz,T.L.and Kidokoro,Y.: "Selective effects of neuronal-synaptobrevin mutation on transmitter release evoked by sustained versus transient Ca^<2+> increases and by cAMP"J.Neurosci.. 19. 2432-2441 (1999)

Yoshihara,M.、Ueda,A.、Zhang,D.、Deitcher.D.L.Schwarz,T.L. 和 Kidokoro,Y.：“神经元突触短蛋白突变对持续与瞬时 Ca^2 > 引起的递质释放的选择性影响增加和

Kuromi H.and Kidokoro Y.: "The optically determined size of exo/endo cycling vesicle pool correlates with the quantal content at the neuromuscular junction of Drosophila larvae"J. Neurosci.. 19. 1557-1565 (1999)

Kuromi H.和 Kidokoro Y.：“光学确定的外/内循环囊泡池的大小与果蝇幼虫神经肌肉接头处的量子含量相关”J.

Yoshihara, M., Ueda, A., Zhang, D., Deitcher, D.L., Schwarz, T.L. and Kidokoro, Y.: "Selective effects of neuronal-synaptobrevin mutations on transmitter release evoked by sustained versus transient CaィイD12+ィエD1 increase and cAMP."J. Neurosci.. 19. 2432-2

Yoshihara, M.、Ueda, A.、Zhang, D.、Deitcher, D.L.、Schwarz, T.L. 和 Kidokoro, Y.：“神经元突触短蛋白突变对持续与短暂 CaD12+ D1 增加和 cAMP 引起的递质释放的选择性影响。 “神经科学杂志.. 19. 2432-2