Synaptic Vesicle Trafficking in Hippocampal Synapses

修订摘要部分 大脑功能严重依赖于突触的正常运作及其修饰能力。一个 了解突触传递和可塑性的基本特性对于阐明 疾病中突触功能障碍的机制。近年来，在以下方面取得了实质性进展： 了解通过突触囊泡胞吐作用释放神经递质的分子机制， 以及通过内吞作用重新捕获用过的囊泡。但人们对此知之甚少 内吞作用和随后的囊泡再利用之间的重要步骤，以及囊泡是如何 组织在突触末端。不同囊泡池的性质及囊泡的运动 不同池之间的囊泡是突触传递效率的主要决定因素， 持续的活动。重要的是，突触囊泡池和它们的运输是动态调制过程中， 发展，并以某种形式的可塑性。 这项研究计划的总体目标是确定回收和动员的机制， 突触囊泡和参与调节囊泡池的机制。我们特别感兴趣的是 在解剖出这些机制的一类突触，释放GABA作为神经递质。大部分 迄今为止，关于囊泡池和运输的工作涉及释放谷氨酸的兴奋性突触， 隐含的假设是，这些机制可能在不同类型的突触之间共享。但 是谷氨酸能和GABA能突触之间重要差异的明确迹象。的要求 我们自己最近的研究结果，我们将研究在突触囊泡运输GABA能的机制， 突触及其活动调节。我们将联合收割机结合精密的实时显微镜技术 用电生理学、分子生物学和电镜技术研究突触前末梢 突触前功能，由以下目标指导：（i）为了检验活动积极的假设， 调节海马体中抑制性突触处的突触前功能的多个方面，以及（ii） 探讨诱发性递质释放活动依赖性变化的机制 和GABA能突触的短期动力学。 这些实验将阐明GABA能神经元中囊泡运输的基本突触前机制。 以及它们是如何被活动改变的。

Revised Abstract Section Brain function depends critically on the normal operation of synapses and their capacity for modification. An understanding the basic properties of synaptic transmission and plasticity is necessary for illuminating the mechanisms of synaptic dysfunction in disease. In recent years, substantial progress has been made in understanding the molecular mechanisms of neurotransmitter release through exocytosis of synaptic vesicles, as well as on recapture of the spent vesicle through endocytosis. But relatively little is known about the important steps between endocytosis and subsequent reuse of vesicles, as well as on how vesicles are organized within the synaptic terminal. The properties of the different pools of vesicle and the movement of vesicles between different pools are major determinants of the efficacy of synaptic transmission during sustained activity. Importantly, synaptic vesicle pools and their trafficking are dynamically modulated during development, and in some forms of plasticity. The overall objective of this research program is to determine the mechanisms in recycling and mobilization of synaptic vesicles and the mechanisms involved in modulation of vesicle pools. In particular, we are interested in dissecting out these mechanisms in a class of synapses that release GABA as neurotransmitter. Much of the work on vesicle pools and trafficking to date has involved excitatory synapses that release glutamate, with the implicit assumption that the mechanisms are likely to be shared across different types of synapses. But there are clear indications of important differences between glutamatergic and GABAergic synapses. Prompted by our own recent findings, we will investigate the mechanisms in synaptic vesicle trafficking in GABAergic synapses and its regulation by activity. We will combine sophisticated real-time microscopy of individual presynaptic terminals with electrophysiology, molecular biology and electron microscopy to investigate presynaptic function, guided by the following aims: (i) To test the hypothesis that activity positively regulates multiple aspects of presynaptic function at inhibitory synapses in the hippocampus, and (ii) To investigate the mechanisms underlying activity-dependent changes in evoked transmitter release and the short-term dynamics of GABAergic synapses. These experiments will elucidate fundamental presynaptic mechanisms of vesicle traffic in GABAergic synapses and how they are altered by activity.