GLUTAMATE-GATED CHANNELS IN CENTRAL & PERIPHERAL NEURONS

中环谷氨酸门控通道

• 批准号: 7367310
• 负责人: James E Huettner
• 金额: $ 33.25万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7367310
• 关键词: 6-Cyano-7-nitroquinoxaline-2,3-dione; AMPA Receptors; Abbreviations; Absence of pain sensation; Acids; Address; Affect; Agonist; Alkanesulfonates; Amino Acids; Amprenavir; Analgesics; Arachidonic Acids; Arginine; Attention; Benzodiazepines; Brain; Brain Pathology; Cell Death; Cell surface; Cells; Chemosensitization; Clinical; Communication; Condition; Cytoplasmic Protein; Epilepsy; Excitatory Synapse; Explosion; Extracellular Domain; Fatty Acids; Funding; GYKI 53655; Gated Ion Channel; Glutamate Receptor; Glutamates; Goals; Green Fluorescent Proteins; Helix (Snails); Individual; Intervention; Ion Channel; Ion Channel Gating; Ischemia; Kainic Acid Receptors; Laboratories; Learning; Light; Lipid Mobilization; Lipids; Location; Mediator of activation protein; Membrane; Membrane Proteins; Molecular; Mutation; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; Names; Naphthalene; Naphthalenes; Nervous system structure; Neurodegenerative Disorders; Neurons; Neurotransmitters; Nonesterified Fatty Acids; Numbers; Operative Surgical Procedures; Paper; Pathologic; Peripheral; Pharmaceutical Preparations; Phospholipase A2; Physiological; Play; Point Mutation; Post-Traumatic Epilepsy; Property; Propionic acid; RNA Editing; Recombinants; Regulation; Research; Role; SYM 2081; Signal Transduction; Site; Site-Directed Mutagenesis; Specific qualifier value; Stimulus; Structure; Synapses; Synaptic Transmission; Testing; Thinking; Traumatic Brain Injury; Unsaturated Fatty Acids; Work; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; amino 3 hydroxy 5 methylisoxazole 4 propionate; base; brain electrical activity; density; ear helix; extracellular; follow-up; inhibitor/antagonist; interest; kainate; lipid mediator; n-pentanoic acid; postsynaptic; presynaptic; prevent; receptor; research study; small molecule

DESCRIPTION (provided by applicant): The long-term objective of my work is to provide a better understanding of synaptic transmission by studying the operation of NMDA, AMPA and kainate receptors, which form ion channels gated by the neurotransmitter glutamate. Another major goal is to uncover properties of these receptors that may allow for clinical intervention to prevent excitotoxic cell death or to provide analgesia. The experiments in this proposal arise from two interesting discoveries that we made during the current period of support. Specific Aim 1 follows up on our observation that kainate receptor block by cis-unsaturated fatty acids, such as docosahexanoic acid (DHA), depends on RNA editing at the Q/R site in the channel pore. Channels with subunits in the edited (R) form are strongly blocked, but inclusion of subunits with a (Q) at the Q/R site dramatically weakens inhibition. Site-directed mutagenesis in the pore loop segment will be used to test the structural basis for this regulation of recombinant channels. Specific Aim 2 builds on our discovery that mutations near the extracellular end of the M3 helix regulate fatty acid block. Chimeric subunits and point mutations will be used to determine the structural requirements for fatty acid inhibition in domains outside of the pore loop segment tested in Aim 1. Specific Aim 3 will analyze channel modulation resulting from release of endogenous lipid-derived mediators. Stimuli relevant to normal brain electrical activity, and to a variety of brain pathologies associated with fatty acid release, will be used to trigger lipid mobilization. The experiments will make use of subunits that resist fatty acid modulation as well as small molecule antagonists that we have discovered which block fatty acid potentiation of NMDA receptors. Collectively, these experiments will shed light on the operation and regulation of neuronal glutamate receptors. Subunits that make up these receptors are all homologous to each other and are thought to share the same membrane topology. Structural differences among the subunits underlie the unique contributions made by NMDA, AMPA and kainate receptors to synaptic communication. Our experiments focus on structural features that allow for differential regulation of receptors with specific subunit composition. A number of pathologic conditions, including brain trauma, epilepsy, and ischemia, elicit massive release of cis-unsaturated fatty acids. These compounds directly regulate many different membrane proteins including a number of ion channel subtypes. This project analyzes the molecular basis of glutamate receptor modulation by DHA, which is present at high levels in the nervous system and is known to be essential for normal brain function.

描述（由申请人提供）：我工作的长期目标是通过研究NMDA，AMPA和海藻酸盐受体的运行来更好地理解突触传播，该操作形成了由神经递质谷氨酸的离子通道。另一个主要目标是发现这些受体的特性，这些受体可能允许临床干预以防止兴奋性细胞死亡或提供镇痛。该提案中的实验源于我们在当前支持期间提出的两个有趣的发现。具体目标1遵循我们的观察结果，即通过顺式不饱和脂肪酸（例如docosahecosahensoic Acid（DHA））取决于在通道孔隙中的Q/R位点上编辑的RNA编辑。在编辑形式（r）形式中具有亚基的通道被强烈阻塞，但在Q/R位点的亚基包含（Q）的亚基大大削弱了抑制作用。孔回路段中的位置定向诱变将用于测试这种调节重组通道的结构基础。具体的目标2建立在我们发现的发现M3螺旋外末端附近的突变调节脂肪酸块。嵌合亚基和点突变将用于确定AIM 1中测试的孔环节段外脂肪酸抑制的结构要求。特定的AIM 3将分析因释放内源性脂质介体的释放而导致的通道调制。与正常脑电活动有关的刺激以及与脂肪酸释放相关的多种脑病理学的刺激将用于触发脂质动员。实验将利用抵抗脂肪酸调节的亚基以及我们发现哪种阻断NMDA受体的脂肪酸增强的小分子拮抗剂。总的来说，这些实验将阐明神经谷氨酸受体的操作和调节。组成这些受体的亚基都是彼此同源的，被认为共享相同的膜拓扑。亚基之间的结构差异是NMDA，AMPA和Kainate受体对突触交流的独特贡献。我们的实验集中于结构特征，这些特征允许对具有特定亚基组成的受体进行差异调节。许多病理状况，包括脑外伤，癫痫和缺血，引起顺式不饱和脂肪酸的大规模释放。这些化合物直接调节许多不同的膜蛋白，包括许多离子通道亚型。该项目通过DHA分析了谷氨酸受体调节的分子基础，DHA在神经系统中的高水平存在，已知对于正常的脑功能至关重要。