NEUROTROPHINS AND SYNAPTIC PLASTICITY

神经营养因子和突触可塑性

• 批准号: 6301937
• 负责人: Mark R. Plummer
• 金额: $ 14.52万
• 依托单位: UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6301937
• 关键词: AMPA receptors; NMDA receptors; SDS polyacrylamide gel electrophoresis; developmental neurobiology; embryo /fetus tissue /cell culture; enzyme inhibitors; glia; glutamate receptor; hippocampus; immunoprecipitation; iontophoresis therapy; laboratory rat; neural plasticity; neural transmission; neurotransmitter transport; neurotrophic factors; phosphorylation; protein biosynthesis; protein kinase; receptor binding; receptor sensitivity; second messengers; synapses; voltage /patch clamp; western blottings

Our recent findings reveal that members of the neurotrophin gene family, in addition to supporting the survival and differentiation of multiple neuronal populations, also modulate synaptic transmission in the hippocampus. These novel trophin effects may play an important role in developmental plasticity and learning and memory. We now propose to identify the molecular basis of trophic regulation of synaptic plasticity, by integrating electrophysiological and molecular biochemical studies of synaptic membranes, isolated neurons, and brain slices. We have previously shown that application of BDNF or NT-4 enhances the strength of glutamatergic synapses via phosphorylation-dependent postsynaptic mechanism(s). Our initial electrophysiological experiments will combine whole-cell path clamp recording with iontophoretic application of transmitters to assess potential changes in receptor sensitivity. Specific protein kinase agonists and antagonist will be used to identify the signaling pathway(s) that mediate the trophin effect. Single-channel recordings will also be made to determine whether BDNF increase the number of active receptors or the properties of existing receptors. In parallel, we will perform biochemical studies of isolated postsynaptic densities (PSDs) to elucidate the specific molecular components activated by BDNF. We have recently shown that trkB, the high affinity receptor for BDNF, is an active component of the PSD, and activation of trkB increases phosphorylation of specific glutamate receptor subunits. The proposed studies will identify the trkB-associated primary effectors in the PSD that mediate this effect. Moreover, we will incorporate peptide mapping to identify the phosphorylated amino acid residues of target receptors. The latter stages of the project will focus on functional aspects, including trophic modulation of activity-dependent synaptic plasticity in hippocampal slices and contributions of local glial cells. Overall, we hope to contribute to our understanding of the multiple critical roles played by neurotrophins in the developing and adult brain.

我们最近的研究结果表明，神经营养素基因家族的成员， 除了支持多种细胞的生存和分化 神经元群体，也调节突触传递 海马体。这些新颖的营养蛋白效应可能在以下方面发挥重要作用： 发育可塑性以及学习和记忆。我们现在建议 确定突触可塑性营养调节的分子基础， 通过整合电生理学和分子生化研究 突触膜、分离的神经元和脑切片。 我们之前已经证明应用 BDNF 或 NT-4 可以增强 通过磷酸化依赖性谷氨酸突触的强度 突触后机制。我们最初的电生理学实验 将全细胞路径钳记录与离子电渗疗法相结合 应用发射器评估受体的潜在变化 敏感性。将使用特定的蛋白激酶激动剂和拮抗剂 确定介导肌营养蛋白效应的信号通路。 还将进行单通道录音以确定 BDNF 是否 增加活性受体的数量或现有受体的特性 受体。 与此同时，我们将对孤立的突触后进行生化研究 密度（PSD）来阐明激活的特定分子成分 通过 BDNF。我们最近发现 trkB，一种高亲和力受体 BDNF 是 PSD 的活性成分，trkB 的激活会增加 特定谷氨酸受体亚基的磷酸化。拟议的 研究将确定 PSD 中与 trkB 相关的主要效应器 介导这种效应。此外，我们将把肽图谱纳入 识别靶受体的磷酸化氨基酸残基。这 该项目的后期阶段将侧重于功能方面，包括 活动依赖性突触可塑性的营养调节 海马切片和局部神经胶质细胞的贡献。总的来说，我们 希望有助于我们对多重关键角色的理解 由发育中和成人大脑中的神经营养素发挥作用。