INTERACTION OF HYPOXIC AND EXCITOTOXIC NEURONAL INJURY

缺氧和兴奋性神经元损伤的相互作用

• 批准号: 3122003
• 负责人: JANET M DUBINSKY
• 金额: $ 15.19万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1994-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3122003
• 关键词: acidity /alkalinity; brain injury; brain metabolism; calcium binding protein; calcium flux; cell death; cerebral ischemia /hypoxia; cyanides; digital imaging; dizocilpine; electrophysiology; excitatory aminoacid; fluorescence microscopy; glia; glutamate receptor; glutamates; hippocampus; immunocytochemistry; inhibitor /antagonist; laboratory rat; neurons; neuropharmacology; neurotoxins; quinoxalines; receptor sensitivity; tissue /cell culture; voltage /patch clamp

This proposal examines the relationship between hypoxic neuronal damage and glutamate (GLU) neurotoxicity. An hypoxic-ischemic episode, as might occur focally during stroke or cerebral hemorrhage or globally during cardiac arrest, results in the accumulation of external GLU and neurodegeneration. It is unknown if hypoxia-induced neuronal lysis liberates excessive GLU or if metabolically compromised, intact neurons release GLU which then exerts further toxic effects. A detailed hypothesis is presented to explain the elevations of intracellular free calcium ion (Cal) and accumulation of endogenous GLU following metabolic compromise. In this model, eventual toxicity results from the enhanced deleterious effects GLU rather than the initial hypoxia. Combinations of hypoxic insult and exogenously applied GLU are expected to produce additive, or supraadditive, effects in this scheme. Experiments are proposed to measure survival of dissociated, hippocampal neurons maintained in a tissue culture environment after individual and combined exposure to excitatory amino acids (EAA), oxygen deprivation, and sodium cyanide (NaCN) as a model of "chemical hypoxia". Additional measurements will be made of resting and altered levels of Cal and intracellular pH (pH1) to determine involvement of these ions in the response to toxic insult and in the signal pathway leading to neuronal death. Methods are proposed for documenting the release of endogenous glutamate after hypoxic insult. Surviving neurons will be examined for their physiological responses to EAA and for the presence or absence of specific cytoplasmic calcium-binding proteins to identify cellular processes possibly conferring resistance to toxic insults.

该提案研究了缺氧神经元损伤之间的关系 和谷氨酸（GLU）神经毒性。 缺氧缺血发作，可能 局部发生在中风或脑出血期间，或全身发生在 心脏骤停，导致外部 GLU 和 神经变性。 目前尚不清楚缺氧是否会导致神经元溶解 释放过量的 GLU，或者如果代谢受损，则释放完整的神经元 释放 GLU，然后发挥进一步的毒性作用。 详细的 提出假设来解释细胞内游离 钙离子 (Cal) 和代谢后内源性 GLU 的积累 妥协。 在这个模型中，最终的毒性是由增强的 有害影响 GLU 而不是最初的缺氧。 的组合 缺氧损伤和外源性应用 GLU 预计会产生 该方案中的加性或超加性效应。 实验是 提议测量分离的海马神经元的存活率 单独和组合后维持在组织培养环境中 暴露于兴奋性氨基酸 (EAA)、缺氧和钠 氰化物（NaCN）作为“化学缺氧”的模型。 附加测量 由静息和改变的 Cal 水平和细胞内 pH 值组成 (pH1) 以确定这些离子参与有毒物质的反应 损伤和导致神经元死亡的信号通路。 方法有 建议记录内源性谷氨酸盐后的释放 缺氧侮辱。 幸存的神经元将被检查 对 EAA 的生理反应以及是否存在 特定的细胞质钙结合蛋白来识别细胞 过程可能赋予对有毒损伤的抵抗力。