Molecular Organization of CNS Synapses

描述（由申请人提供）： 哺乳动物的大脑主要由神经递质谷氨酸介导， 两类突触后谷氨酸受体：NMDA受体和AMPA 受体（NMDAR和AMPAR）。我们的长期目标是了解 谷氨酸受体靶向谷氨酸受体的分子机制 突触后膜，以及如何调节这些机制，以控制突触后膜， 突触传递的强度。因此，这项建议涉及一个 突触可塑性的基本问题，这与大脑 发展以及学习和记忆。 最近的研究表明，突触后AMPAR的调节性运输是一个重要的机制。 长期增强和抑制的主要机制 突触传递然而，细胞生物学事件仅仅是 表面上（主要是定性）描述，和基础 分子机制仍然知之甚少。解决这些重要 问题，我们将使用定量免疫细胞化学和生物化学 技术全面调查AMPAR内化（内吞作用） 和插入（胞吐）。分子 AMPAR内化/插入受突触调节的机制 将用亚基GluR 1和GluR 2研究活性和生长因子。的 在神经元表面中的新AMPAR插入位点将在高浓度下可视化。 分辨率此外，我们将寻找和功能表征新的 可能在AMPAR运输中起作用的AMPAR结合蛋白，因此 突触可塑性最后，分子的功能意义 研究结果将通过海马神经元电生理实验进行验证。 切片在每个目标中，我们都有强大的初步数据， 证明了其重要性，并证明了其可行性。 提出的实验。 由于谷氨酸受体的功能与脑突触 功能和兴奋性毒性，这项研究可能与人类急性和 慢性神经变性疾病和精神疾病。

DESCRIPTION (provided by applicant): Excitatory synaptic transmission in the mammalian brain is primarily mediated by the neurotransmitter glutamate acting on two classes of postsynaptic glutamate receptors: NMDA receptors and AMPA receptors (NMDARs and AMPARs). Our long-term objective is to understand the molecular mechanisms by which glutamate receptors are targeted to the postsynaptic membrane and how these mechanisms can be regulated to control the strength of synaptic transmission. This proposal therefore addresses a fundamental issue in synaptic plasticity, which is of relevance to brain development and to learning and memory. Recent studies suggest that regulated trafficking of postsynaptic AMPARs is a major mechanism underlying the long-lasting potentiation and depression of synaptic transmission. However, the cell biological events have only been superficially (and largely qualitatively) described, and the underlying molecular mechanisms remain poorly understood. To address these important questions, we will use quantitative immunocytochemical and biochemical techniques to comprehensively investigate AMPAR internalization (endocytosis) and insertion (exocytosis) in cultured hippocampal neurons. The molecular mechanisms by which AMPAR internalization/insertion is regulated by synaptic activity and growth factors will be studied with subunits GluR1 and GluR2. The site of new AMPAR insertion in the neuronal surface will be visualized at high resolution. In addition, we will search for and functionally characterize novel AMPAR-binding proteins that may play a role in AMPAR trafficking, and hence synaptic plasticity. Finally, the functional significance of the molecular findings will be tested by electrophysiological experiments in hippocampal slices. In each of these aims, we have strong Preliminary Data that substantiate the significance and that demonstrate the feasibility of the proposed experiments. Because glutamate receptor function is intimately involved in brain synaptic function and excitotoxicity, this research may be relevant to human acute and chronic neurodegenerative disease and to psychiatric disorders.