EXCITATORY AMINO ACIDS AND HYPOXIC DAMAGE IN THE CNS

本研究的总体目标是分析免疫细胞化学 兴奋性氨基酸神经递质的分布 视网膜，并将这种分布与神经元的易感性 缺氧损伤 大量证据表明兴奋性氨基酸 酸及其类似物在包括视网膜在内的CNS中作为毒素。 最近 体内和体外研究表明，缺氧神经元损伤需要 兴奋性氨基酸突触释放与缺氧或缺血 神经元死亡可以通过给予兴奋性氨基甲酸酯来预防 酸拮抗剂 细胞外浓度大幅增加 谷氨酸盐和天冬氨酸盐的含量在海马体中进行了测量， 分钟的诱导缺血。 我们计划的调查 假定的兴奋性氨基酸在缺氧神经元损伤中的作用是 具体目标如下： (1)研制高特异性的半胱氨酸单克隆抗体 亚磺酸盐，半胱氨酸和牛磺酸使用类似的方法，我们有 以前用于提高单克隆抗体的高度特异性， 固定剂修饰的谷氨酸和天冬氨酸。 (2)为了确定强烈的视网膜中的具体位置， 这些单克隆抗体的免疫反应性， 电镜 (3)为了联合收割机和修改两个现有的模型（谷氨酸毒性， 视网膜和海马神经元培养中的缺氧损伤），从而 建立一种新的鸡胚神经元缺氧模型 视网膜，并证明视网膜神经元选择性地敏感于 缺氧损伤具有来自具有强烈兴奋性神经元的突触输入 氨基酸免疫反应性。 (4)探讨神经元对缺氧损伤的可能保护作用 在该模型系统中，通过给予兴奋性氨基酸 对手。 这些研究将测试临床上重要的概念， 特定的兴奋性氨基酸在突触处处于高浓度， 对缺氧损伤敏感的神经元。

The overall goal of this research is to analyze the immunocytochemical distribution of putative excitatory amino acid neurotransmitters in the retina and to relate this distribution to that of neuronal susceptibility to hypoxic damage. An abundance of evidence implicates excitatory amino acids and their analogs as toxins in the CNS including the retina. Recent studies in vivo and in vitro indicate that hypoxic neuronal damage requires the synaptic release of excitatory amino acids and that hypoxic or ischemic neuronal death can be prevented by the administration of excitatory amino acid antagonists. Very large increases in the extracellular concentrations of glutamate and aspartate have been measured in the hippocampus within minutes of the induction of ischemia. Our proposed investigations of the role of putative excitatory amino acids in hypoxic neuronal lesions are described by the following specific aims: (1) To develop monoclonal antibodies with high specificity for cysteine sulfinate, cysteate and taurine using methods similar to those we have previously employed to raise monoclonal antibodies highly specific for fixative-modified glutamate and aspartate. (2) To determine the specific location in the retina of intense immunoreactivity for these monoclonal antibodies using both light and electron microscopy. (3) To combine and modify two existing models (for glutamate toxicity in retina and hypoxic damage in hippocampal neuronal culture) and thereby develop a new model for neuronal hypoxia using cultured embryonic chick retina and demonstrate that retinal neurons selectively susceptible to hypoxic damage have synaptic input from neurons with intense excitatory amino acid immunoreactivity. (4) To investigate the possible protection of neurons from hypoxic damage in this model system by administration of excitatory amino acid antagonists. These studies will test the clinically important concept that specific excitatory amino acids are in high concentrations at synapses upon neurons that are selectively sensitive to hypoxic damage.