Contribution of active zone subpopulation of vesicles to evoked and spontaneous release

作     者：Koenig, JH Ikeda, K 

作者机构：City Hope Natl Med Ctr Beckman Res Inst Div Neurosci Duarte CA 91010 USA 

出 版 物：《JOURNAL OF NEUROPHYSIOLOGY》 (神经生理学杂志)

年 卷 期：1999年第81卷第4期

页      面：1495-1505页

核心收录：

学科分类：0710[理学-生物学] 1001[医学-基础医学(可授医学、理学学位)] 07[理学] 071003[理学-生理学] 

基　　金：NINDS NIH HHS [NS-18856] Funding Source: Medline 

主　　题：果蝇蛋白质类 黑腹果蝇/遗传学 动力蛋白质类 GTP磷酸水解酶类/遗传学 显微镜检查 电子 微管/生理学 微管/超微结构 突变/生理学 神经肌肉接头/生理学 神经肌肉接头/超微结构 突触传递/遗传学 突触小泡/生理学 突触小泡/超微结构 温度 动物 女(雌)性 

摘      要：Our previous work on Drosophila synapses has suggested that two vesicle populations possessing different recycling pathways, a fast pathway emanating from the active zone and a slower pathway emanating from sites away from the active zone, exist in the terminal. The difference in recycling time between these two pathways has allowed us to create a synapse that possesses the small, active zone subpopulation without the larger, nonactive zone population. Synapses were depleted using the temperature-sensitive endocytosis mutant, shibire, which reversibly blocks vesicle recycling at the restrictive temperature. In the depleted state, both the excitatory junction potential (EJP) and spontaneous release are abolished. After shibire-induced depletion. the active zone population begins to reform within 30 s at the permissive temperature. whereas the nonactive zone population does not begin to reform until similar to 10-15 min later. Evoked release recovered at approximately the same time as the active zone population. During the time when the active zone population existed in the terminal without the nonactive zone population, enough transmitter release was available to sustain a normal evoked response for many minutes at frequencies above those produced during normal activity (flight) by this motor neuron. When only the active zone population existed in the terminal, the frequency of spontaneous release was greatly attenuated and possessed abnormal release characteristics. Spontaneous release recovered its predepletion frequency and release characteristics only after the nonactive zone population was reformed.