Plasticity of Electrical Synapses

电突触的可塑性

• 批准号: 8277328
• 负责人: Alberto E Pereda
• 金额: $ 32.56万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8277328
• 关键词: Acoustic Nerve; Address; Area; Auditory; Auditory system; Botulinum Toxins; Brain; Ca(2+)-Calmodulin Dependent Protein Kinase; Calmodulin; Cells; Chemical Synapse; Chemicals; Chemosensitization; Cognitive; Communication; Connexins; Coupling; Electrical Synapse; Endocytosis; Enzyme Activation; Epilepsy; Exocytosis; Fishes; Functional disorder; Gap Junctions; Glutamate Receptor; Glutamates; Goals; Goldfish; Health; Impairment; Injection of therapeutic agent; Investigation; M cell; Mediating; Mental Depression; Modality; Modeling; Modification; Molecular; Molecular Analysis; N-Methyl-D-Aspartate Receptors; Neurons; Orthologous Gene; Peptides; Phosphotransferases; Physiological; Plastics; Presynaptic Terminals; Process; Property; Proteins; Regulation; Research; Role; Scaffolding Protein; Surface; Synapses; System; Testing; Tight Junctions; Work; connexin 36; developmental disease; electrical property; gap junction channel; genetic regulatory protein; in vivo; novel; prevent; protein protein interaction; response; scaffold; trafficking; transmission process

DESCRIPTION (provided by applicant): The goal of this proposal is to investigate the role and properties of gap junction-mediated electrical synapses in the auditory system. Auditory afferents terminating as large mixed (electrical and chemical) synaptic terminals on the goldfish Mauthner cell are ideally suited for these studies since unlike mammalian electrical synapses, the experimental accessibility makes it possible to quantify in vivo changes in junctional conductance that occur under different physiological conditions and to correlate them with anatomical, ultrastructural and molecular analysis. Strikingly, the conductance of these model electrical synapses is under the fine regulatory control of neuronal activity. Electrical transmission is mediated by connexin 35 (Cx35), the fish ortholog of the mammalian connexin 36 (Cx36) which is present in the auditory system, suggesting that mammalian auditory electrical synapses could be similarly regulated. This proposal deals on understanding the molecular mechanisms underlying the bi-directional control of junctional conductance at these terminals by focusing in the role of regulated trafficking of gap junction channels. Aim 1 is to investigate the existence of trafficking of gap junction channels at native electrical synapses, in vivo, by combining ultrastructural and pharmacological approaches. Our preliminary results suggest the existence of an active turnover of gap junction channels, which constitute the first evidence of this phenomenon in a native synapse. Aim 2 is to determine the contribution of regulated trafficking to activity-dependent potentiation of electrical transmission. It will test if mechanisms of exocytosis are required for the expression of the potentiation and if it requires of direct interactions with the regulatory kinase CaM-KII and the scaffold protein ZO-1. Conversely, Aim 3 will investigate the possible contribution of regulated trafficking to activity-dependent depression of electrical transmission. Using similar approaches, we will investigate if mechanisms of endocytosis are required for activity-dependent depression of junctional conductance, as well the potential roles of direct protein-protein interactions. Furthermore, the direct interactions of CaM-KII and ZO-1 through conserved regions of both Cx35 and Cx36 suggests that its function might underlie a fundamental and widespread property of electrical transmission, also relevant to mammalian electrical synapses. Thus, the proposed research addresses the novel concept that the strength of electrical synapses is achieved by dynamically regulating the trafficking of gap junction channels. Because electrical synapses have been shown to promote coordinated neuronal activity, dysfunction of this regulation could have profound pathological implications, contributing to auditory impairment, epilepsy and cognitive (psychiatric) and developmental disorders PUBLIC HEALTH RELEVANCE: The proposal explores the molecular mechanisms involved in the regulation of gap junction-mediated electrical synapses. Further, the proposal explores the role of regulated trafficking of gap junction channels as their underlying mechanism. This process has been shown involved in the regulation of chemical synapses, but no evidence suggests its participation in electrical synapses. Thus, the proposal investigates the possibility that both chemical and electrical synapses share common regulatory mechanisms. Because electrical synapses have been shown to promote coordinated neuronal activity, dysfunction of their regulation could have profound pathological implications, contributing to epilepsy and to cognitive (psychiatric) and developmental disorders.

描述（由申请人提供）：该提案的目的是研究听觉系统中GAP连接介导的电气突触的作用和特性。在金鱼Mauthner细胞上终止以大型混合（电气和化学）突触终端终止的听觉传入非常适合这些研究并将它们与解剖学，超微结构和分子分析相关联。令人惊讶的是，这些模型电气突触的电导率在神经元活性的良好调节控制下。电气传递是由connexin 35（CX35）介导的，这是听觉系统中存在的哺乳动物连接蛋白36（CX36）的鱼类直系同源物，这表明可以类似地调节哺乳动物的听觉电气突触。该提案涉及了解这些终端连接电导的双向控制的分子机制，通过关注受调节的间隙连接通道的贩运作用。目的1是通过结合超微结构和药理学方法来调查在体内的天然电气突触中间隙连接通道的存在。我们的初步结果表明存在间隙连接通道的积极离职，这构成了天然突触中这种现象的第一个证据。目的2是确定受调节贩运对活动依赖性电动传输增强的贡献。它将测试是否需要与调节激酶CAM-KII和支架蛋白ZO-1进行直接相互作用的增强表达以及是否需要直接相互作用。相反，AIM 3将研究受调节贩运对活动依赖性电动传播抑郁症的可能贡献。使用类似的方法，我们将研究是否需要内吞作用的机理，以依赖活性的连接电导抑郁症，以及直接蛋白质蛋白相互作用的潜在作用。此外，CAM-KII和ZO-1通过CX35和CX36的保守区域的直接相互作用表明，其功能可能是电气传播的基本和广泛特性的基础，这也与哺乳动物电气突触有关。因此，拟议的研究探讨了新的概念，即电突触的强度是通过动态调节间隙连接通道的运输来实现的。由于已经显示出电气突触促进了协调的神经元活性，因此该调节的功能障碍可能具有深远的病理意义，从而有助于听觉障碍，癫痫和认知（精神病）和发育障碍 公共卫生相关性：该提案探讨了与间隙连接介导的电气突触调节有关的分子机制。此外，该提案探讨了受规则贩运间隙连接通道作为其基本机制的作用。该过程已参与化学突触的调节，但没有证据表明其参与电气突触。因此，该提案调查了化学和电突触具有共同调节机制的可能性。由于电气突触已被证明促进了协调的神经元活性，因此其调节的功能障碍可能具有深远的病理意义，有助于癫痫和认知（精神病）和发育障碍。