GLUTAMATE-GATED CHANNELS IN CENTRAL & PERIPHERAL NEURONS

中环谷氨酸门控通道

基本信息

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
项目类别：
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

项目摘要

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 和红藻氨酸受体的运作来更好地理解突触传递，这些受体形成由神经递质谷氨酸门控的离子通道。另一个主要目标是揭示这些受体的特性，从而可以进行临床干预以防止兴奋性毒性细胞死亡或提供镇痛作用。该提案中的实验源于我们在当前支持期间做出的两个有趣的发现。具体目标 1 是根据我们的观察得出的，即顺式不饱和脂肪酸（例如二十二碳六烯酸 (DHA)）对红藻氨酸受体的阻断取决于通道孔中 Q/R 位点的 RNA 编辑。具有编辑 (R) 形式的亚基的通道被强烈阻断，但在 Q/R 位点包含具有 (Q) 的亚基会显着削弱抑制作用。孔环片段中的定点诱变将用于测试重组通道调节的结构基础。具体目标 2 建立在我们的发现之上，即 M3 螺旋细胞外端附近的突变调节脂肪酸阻断。嵌合亚基和点突变将用于确定目标 1 中测试的孔环片段之外的域中脂肪酸抑制的结构要求。具体目标 3 将分析内源性脂质衍生介体释放导致的通道调节。与正常脑电活动以及与脂肪酸释放相关的各种脑部病理相关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的可阻断 NMDA 受体脂肪酸增强的小分子拮抗剂。总的来说，这些实验将揭示神经元谷氨酸受体的运作和调节。组成这些受体的亚基彼此同源，并且被认为具有相同的膜拓扑结构。亚基之间的结构差异是 NMDA、AMPA 和红藻氨酸受体对突触通讯做出独特贡献的基础。我们的实验侧重于允许对具有特定亚基组成的受体进行差异调节的结构特征。许多病理状况，包括脑外伤、癫痫和缺血，都会引起顺式不饱和脂肪酸的大量释放。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。该项目分析了 DHA 调节谷氨酸受体的分子基础，DHA 在神经系统中含量很高，已知对正常大脑功能至关重要。