EXCITATORY AMINO ACIDS AND NEUROTOXICITY

兴奋性氨基酸神经毒性机制的研究 在方案项目的初期(1900-1992年)进行了 证实在滥用EAA受体刺激神经元的过程中 动态平衡机制不堪重负，病理性动态平衡 细胞内游离钙和蛋白激酶的失稳(HD) 随之而来的是C(PKC)易位。[Ca~(2+)](I)和PKC的这种ISD触发 随后钙依赖酶(蛋白水解酶， 鸟氨酸，脱羧酶，没有合成酶)，最终可能会带来 迟发性神经元死亡。我们研究的长期目标是利用 动态平衡失稳抑制剂(HDI)治疗慢性阻塞性肺疾病 滥用EAA受体刺激引起的继发性神经元损伤 在脑缺血、创伤和阿尔茨海默病之后。理想的HDI 应该：1)专门针对 危险，不阻断EAA介导的突触传递未受影响 执行重要代偿功能的大脑区域；2)允许 只有病理后果的药理学矫正 导致神经元死亡的病理过程；(3)允许药物 终止EAA受体滥用侮辱后的干预。至 设计理想的HDI我们应该能够完全理解信号 专门区分信号转导的放大步骤 以下是生理性谷氨酸受体的使用 病理性的受体滥用。为此，该项目将重点放在 1)体外测定(原代培养神经元， 小脑和大脑皮层)[Ca~(2+)]的分子机制 EaaS受体滥用。一系列机制运行以保持 神经元内[Ca~(2+)]的稳态(I)--这些机制包括a)血浆 膜钙通道(VOC或ROC)，b)质膜Na+交换器， C)Ca~(2+)-ATPase，将Ca~(2+)泵过神经细胞膜，d) 内质网膜上的转运蛋白和 线粒体，e)钙结合蛋白。在这一具体目标中，我们计划 挑出主要机构或机构星座 这有助于[Ca](I)2的HD在体内研究EAA受体是如何 滥用涉及PKC的长期激活和转位，以及 局灶性脑缺血损伤周围区域的神经元损伤。 我们开始研究生化、组织化学和神经学变化。 在大鼠局灶性脑缺血模型中发生 大脑皮层光化学Rose Bengal法(35例)。如果EAA滥用 参与受体刺激，阻断NMDA，非NMDA谷氨酸 受体和神经节苷脂应该抑制 半影区和减少区神经元的病理生理事件 由光化学中风引起的行为缺陷。

Studies on the mechanisms of excitatory amino acid (EAA) neurotoxicity conducted in the initial period (1900-1992) of the program project have established that during abusive EAA receptor stimulation the neuronal homeostatic mechanisms are overwhelmed and a pathological homeostatic destabilization (HD) of free cytosolic Ca ([Ca2+](i) and protein kinase C (PKC) translocation ensues. This ISD of [Ca2+](i) and PKC triggers the subsequent overactivation of Ca2+-dependent enzymes (proteases, ornithine, decarboxylase, NO synthase) that ultimately may bring about delayed neuronal death. The long term goal of our research is to utilize homeostatic destabilization inhibitors (HDI) for the treatment of secondary neuronal damage due to abusive EAA receptor stimulation following brain ischemia, trauma, and Alzheimer's disease. An ideal HDI should: 1) be targeted specifically to the brain structures that are in danger, without blocking EAA mediated synaptic transmission in unaffected brain areas that perform compensatory vital functions; 2) allow the pharmacological rectification of only the pathological consequences of the pathological process leading to neuronal death; (3) allow drug intervention after termination of the EAA receptor abusive insult. To design ideal HDI we should be able to fully understand the signal amplification steps that specifically differentiate signal transduction following physiological glutamate receptor use from that following pathological receptor abuse. To this end the project will be focused on the following: 1) to determine in vitro (primary cultured neurons, cerebellar and cortical) the molecular mechanisms of [Ca2+](i) following EAAs receptor abuse. A number of mechanisms operates to maintain the neuronal homeostasis of [Ca2+](i) - these mechanisms include a) plasma membrane Ca2+ channels (VOC or ROC), b) plasma membrane Na+ exchanger, c) Ca2+ ATPase, which pumps Ca2+ across the neuronal membrane, d) transport proteins on the membrane of the endoplasmic reticulum and the mitochondria, e) Ca2+ binding proteins. In this specific aim we plan to single out the principal mechanism or the constellation of mechanisms that contribute to the HD of [Ca](i) 2) to study in vivo how EAA receptor abuse relates to protracted PKC activation and translocation and to neuronal damage in the area that surrounds a focal ischemic brain lesion. We began to study biochemical, histochemical and neurological changes occurring in rats subjected to focal brain ischemia induced in the cerebral cortex with photochemical Rose Bengal method (35). If EAA abuse receptor stimulation is involved, blockade of NMDA, non-NMDA glutamate receptors and gangliosides should curtail the cascade of pathophysiological events in the neurons of the area penumbra and reduce behavioral deficits caused by the photochemical stroke.