D-aspartate potentiates the effects of both L-aspartate and L-glutamate on carp horizontal cells.
D-aspartate potentiates the effects of both L-aspartate and L-glutamate on carp horizontal cells.
复制标题
D-天冬氨酸增强了 L-天冬氨酸和 L-谷氨酸对鲤鱼水平细胞的作用。
DOI：
10.1016/0306-4522(89)90104-8
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发表时间：
1989
期刊：
影响因子：
3.3
通讯作者：
Dowling,JE
中科院分区：
文献类型：
--
作者：
Mangel,SC;Ariel,M;Dowling,JE
将L-天冬氨酸、L-谷氨酸和D-天冬氨酸单独或联合应用于鲤鱼视网膜，灌流或雾化，同时进行视锥水平细胞记录。当单独使用这些药物时，每种药物都能使水平细胞去极化，并减小其光反应的大小，这一作用模仿了内源性光感受器传递器的作用。D-天冬氨酸与l-氨基酸中的任何一种一起使用，增强了l-氨基酸的作用，与单独使用l-氨基酸相比，阈值浓度降低了约五倍。D-天冬氨酸对所有类型的锥体水平细胞均有增强作用，包括C型和L型细胞。此外，D-天冬氨酸的增强效应不仅发生在黑暗中，而且在强光背景或Co2+离子存在的情况下，光感受器递质的释放被减少或阻断。D-天冬氨酸还增强了酸性氨基酸半胱氨酸亚硫酸盐的去极化作用。D-天冬氨酸的增强作用可归因于其作为视网膜外层氨基酸摄取阻滞剂的作用。因此，这些发现本身并不能排除天冬氨酸、L谷氨酸或半胱氨酸亚硫酸盐作为鲤鱼锥体递质的候选物质。然而，先前报道的其他证据强烈表明，l-谷氨酸和nol-天冬氨酸是锥体递质。
l-Aspartate,l-glutamate andd-aspartate, alone or in combination, were applied by superfusion or by atomization to the isolated carp retina while recording from cone horizontal cells. Each of these agents when applied alone depolarized horizontal cells and reduced the size of their light responses, an action which mimics the effect of the endogenous photoreceptor transmitter. Application ofd-aspartate in conjunction with either of thel-amino acids potentiated the effects of thel-amino acids so that the threshold concentration was reduced by about five-fold, compared to when thel-amino acids were applied alone. The potentiating effect ofd-aspartate occurred with all types of cone horizontal cells—bothl- and C-types. Furthermore, the potentiating effect ofd-aspartate occurred not only in the dark but also in the presence of bright light backgrounds or Co2+ions, conditions during which the release of photoreceptor transmitter is reduced or blocked.d-Aspartate also potentiated the depolarizing effects of the acidic amino acid cysteine sulfinate.The potentiating effect ofd-aspartate can be attributed to its action as an amino acid uptake blocker in the outer retina. Thus, these findings, in themselves, cannot eliminatel-aspartate,l-glutamate or cysteine sulfinate as candidates for the carp cone transmitter. However, other evidence, previously reported, strongly suggests thatl-glutamate and notl-aspartate is the cone transmitter.