Plasticity of Electrical Synapses

电突触的可塑性

• 批准号: 8488425
• 负责人: Alberto E Pereda
• 金额: $ 30.93万
• 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/8488425
• 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

描述（由申请人提供）：该提案的目标是研究听觉系统中间隙连接介导的电突触的作用和特性。金鱼莫特纳细胞上作为大型混合（电和化学）突触末端终止的听觉传入非常适合这些研究，因为与哺乳动物电突触不同，实验的可访问性使得可以量化在不同生理条件下发生的体内连接电导的变化并将它们与解剖学、超微结构和分子分析联系起来。引人注目的是，这些模型电突触的电导受到神经元活动的精细调节控制。电传输由连接蛋白 35 (Cx35) 介导，连接蛋白 35 (Cx35) 是哺乳动物连接蛋白 36 (Cx36) 的鱼类直系同源物，存在于听觉系统中，这表明哺乳动物的听觉电突触也可以受到类似的调节。该提案涉及通过关注间隙连接通道的调节运输的作用来了解这些终端连接电导双向控制的分子机制。目标 1 是通过结合超微结构和药理学方法，研究体内天然电突触间隙连接通道运输的存在。我们的初步结果表明间隙连接通道存在活跃的周转，这是天然突触中这种现象的第一个证据。目标 2 是确定受管制的贩运对活动依赖性电传输增强的贡献。它将测试增强表达是否需要胞吐作用机制，以及是否需要与调节激酶 CaM-KII 和支架蛋白 ZO-1 直接相互作用。相反，目标 3 将研究受管制的贩运对活动依赖性电传输抑制的可能影响。使用类似的方法，我们将研究内吞作用机制是否是连接电导的活性依赖性抑制所必需的，以及直接蛋白质-蛋白质相互作用的潜在作用。此外，CaM-KII 和 ZO-1 通过 Cx35 和 Cx36 的保守区域直接相互作用表明，其功能可能是电传输基本且广泛的特性的基础，也与哺乳动物电突触相关。因此，所提出的研究提出了一个新概念，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。由于电突触已被证明可以促进协调的神经元活动，因此这种调节功能障碍可能会产生深远的病理学影响，导致听觉障碍、癫痫、认知（精神）和发育障碍