[Dual nature of excitatory amino acids in the vertebrate retina].
[Dual nature of excitatory amino acids in the vertebrate retina].
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[脊椎动物视网膜中兴奋性氨基酸的双重性质]。
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
M. Tamai
中科院分区：
文献类型：
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作者：
M. Tamai
谷氨酸作为一种主要的兴奋性氨基酸，在中枢神经系统中起着重要的作用，也是中枢代谢产物之一。这种氨基酸在脊椎动物的中枢神经系统（包括视网膜）中也是一种有毒物质，尤其是在缺血的情况下。本文综述了近年来视网膜谷氨酸代谢及其与视网膜疾病发病机制的关系的研究进展。谷氨酸过量可诱导n-甲基- d -天冬氨酸（NMDA）和非NMDA受体的过度刺激，以及Na+、Cl-和水向突触后元件的内流，导致裂解和肿胀。在缺氧或缺血的情况下，谷氨酸在视网膜的大部分都有积累。缺血引起的形态学和功能改变可以通过预先给药NMDA受体拮抗剂来预防。这些结果表明视网膜存在与中枢神经系统相同的病理机制。他们还建议在不久的将来，一种新的治疗视网膜缺血引起的异常的药理方法可以在眼科临床中引入。谷氨酸脱氢酶是谷氨酸代谢中的一种重要酶，在脊髓小脑变性患者中有异常的报道。其中部分患者出现视网膜营养不良。据报道，这种酶的热不稳定活性的部分缺乏与视网膜异常患者密切相关。提示不仅谷氨酸本身，其代谢途径的异常也可能与视网膜变性的发病机制密切相关。
Glutamic acid plays an important role as a main excitatory amino acid and also as one of the central metabolites in the central nervous system (CNS). This amino acid also acts as a toxic substance in the vertebrate CNS, including the retina, especially in ischemic conditions. This paper reviews recent advances in retinal research on glutamate metabolism and its relationship with pathogenesis of retinal diseases. Excessive administration of glutamate induces overstimulation of N-methyl-D-aspartate (NMDA) and non-NMDA receptors, and influx of Na+, Cl-, and water to postsynaptic elements, causing lysis and swelling. In hypoxic or ischemic conditions, accumulation of glutamate was observed in most parts of the retina. Morphological and functional changes induced by ischemia could be prevented by preadministration of an antagonist of NMDA receptors. These results suggest that the same pathological mechanism as in the CNS exists in the retina. They also suggest that a new pharmacological approach for treating retinal abnormalities caused by ischemia could be introduced in the ophthalmology clinic in the near future. Abnormality of glutamate dehydrogenase, an important enzyme in the glutamate metabolism, has been reported in patients with spinocerebellar degenerations. Retinal dystrophy was also reported in some of them. Partial deficiency of heat-labile activity of this enzyme has been reported to be profoundly related with those patients with retinal abnormalities. This suggests that not only glutamate itself, but also abnormalities in its metabolic path way might be deeply correlated with the pathogenesis of retinal degeneration.