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 兴奋性氨基酸类神经递质在大脑皮层的分布 并将这种分布与神经元敏感性的分布联系起来 造成缺氧性损伤。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中枢神经系统中的毒素。近期 体内和体外研究表明，缺氧性神经元损伤需要 兴奋性氨基酸的突触释放与缺氧或缺血 给予兴奋性氨基可防止神经元死亡 酸性拮抗剂。胞外浓度的极大增加 已经在海马体中测量到谷氨酸和天冬氨酸的 诱导缺血的分钟数。我们建议对 兴奋性氨基酸在缺氧性神经元损伤中的作用 具体目标如下： (1)研制特异性高的半胱氨酸单抗 使用与我们的方法类似的亚硫酸盐、半胱酸盐和牛磺酸 以前曾被用来制备高度特异的单抗 固定剂-改性谷氨酸和天冬氨酸。 (2)确定强直性视网膜病变在视网膜中的具体位置 用LIGH和LIGH检测这些单抗的免疫反应性 电子显微镜。 (3)合并和修改现有的两个模型(针对谷氨酸毒性 视网膜和海马神经元培养中的缺氧性损伤)，从而 用培养的胚胎雏鸡建立神经元缺氧模型 视网膜，并证明视网膜神经元选择性地易受 缺氧性损伤有来自强烈兴奋性神经元的突触输入 氨基酸免疫反应性。 (4)探讨神经元对缺氧性损伤的保护作用 在这个模型系统中，通过给药兴奋性氨基酸 对抗者。这些研究将检验临床上重要的概念 特定的兴奋性氨基酸在突触中浓度很高。 对缺氧性损伤选择性敏感的神经元。

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.