Two phenylglycine derivatives antagonize responses to L-AP4 in ON bipolar cells of the amphibian retina.
Two phenylglycine derivatives antagonize responses to L-AP4 in ON bipolar cells of the amphibian retina.
复制标题
两种苯基甘氨酸衍生物拮抗两栖类视网膜 ON 双极细胞对 L-AP4 的反应。
DOI：
10.1016/s0028-3908(96)00164-5
复制
发表时间：
1997
影响因子：
4.7
通讯作者：
Miller,RF
中科院分区：
文献类型：
--
作者：
Thoreson,WB;Gottesman,J;Jane,DE;Tse,HW;Watkins,JC;Miller,RF
Light responses of retinal ON bipolar cells are mediated by metabotropic glutamate receptors selectively activated by l-2-amino-4-phosphonobutyric acid (l-AP4). Antagonists to l-AP4 receptors in ON bipolar cells have not previously been identified. This study examines the electrophysiological effects of (S)-2-amino-2-methyl-4-phosphonobutanoic acid (MAP4), (RS)-4-chloro-3,5-dihydroxyphenylglycine (CDHPG) and (RS-3,4,5-trihydroxyphenylglycine (THPG), at l-AP4 receptors in ON bipolar cells of the amphibian retina. Unlike its actions in spinal cord, in retinal ON bipolar cells MAP4 is a weak agonist which exhibits no detectable antagonism to l-AP4. On the other hand, CDHPG exhibits a mixture of agonist and antagonist properties. Addition of Co2+and oxygenation of CDHPG turns the solution brown and enhances antagonist effects, suggesting that the antagonism reflects actions of a breakdown product of CDHPG. Although THPG did not prove to be this breakdown product, it also has electrophysiological effects consistent with an l-AP4 receptor antagonist. The results suggest that THPG and breakdown products of CDHPG may be antagonists to l-AP4 receptors in retinal ON bipolar cells, although the possibility that these compounds antagonize effects of l-AP4 by acting at some site in the transduction pathway of l-AP4 receptors cannot yet be excluded. © 1997 Elsevier Science Ltd. All rights reserved.
