GLUTAMATE ANTAGONISTS THAT BLOCK HYPERPOLARIZING BIPOLAR CELLS INCREASE THE RELEASE OF DOPAMINE FROM TURTLE RETINA
GLUTAMATE ANTAGONISTS THAT BLOCK HYPERPOLARIZING BIPOLAR CELLS INCREASE THE RELEASE OF DOPAMINE FROM TURTLE RETINA
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DOI：
10.1017/s0952523800010683
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发表时间：
1992-09-01
影响因子：
1.9
通讯作者：
MARC, RE
中科院分区：
文献类型：
--
作者：
CRITZ, SD;MARC, RE
本文研究了拟龟（Pseudemys scripta elegans）视网膜中调节多巴胺释放的神经元回路的一些神经化学特征。阻断超极化双极细胞的谷氨酸拮抗剂，如2，3哌啶二羧酸（PDA），产生剂量依赖性多巴胺释放。相比之下，谷氨酸激动剂2-氨基-4-磷酸丁酸（APB）可以高度特异性地阻断去极化双极细胞反应，但对多巴胺的释放没有影响。γ-氨基丁酸（GABA）拮抗剂荷包牡丹碱也能产生有效的剂量依赖性多巴胺释放。PDA产生的多巴胺的释放被外源性GABA和蝇蕈醇阻断，这表明PDA介导的释放过程是多突触的，并且涉及在双极和多巴胺能无长突细胞之间插入的GABA能突触。产生多巴胺释放的唯一其他药剂是无氯介质和高细胞外K+;特别是红藻氨酸和谷氨酸本身是无效的。这些结果提示，在海龟视网膜中，介导多巴胺释放的初级神经元链是：视锥细胞>超极化双极细胞> GABA能无长突细胞>多巴胺能无长突细胞。
Some neurochemical features of the neuronal circuitry regulating dopamine release were examined in the retina of the turtle, Pseudemys scripta elegans. Glutamate antagonists that block hyperpolarizing bipolar cells, such as 2,3 piperidine dicarboxylic acid (PDA), produced dose-dependent dopamine release. In contrast, the glutamate agonist 2-amino-4-phosphonobutyric acid (APB), which blocks depolarizing bipolar cell responses with high specificity, had no effect on the release of dopamine. The gamma-aminobutyric acid (GABA) antagonist, bicuculline, also produced potent dose-dependent release of dopamine. The release of dopamine produced by PDA was blocked by exogenous GABA and muscimol, suggesting that the PDA-mediated release process was polysynaptic and involved a GABAergic synapse interposed between the bipolar and dopaminergic amacrine cells. The only other agents that produced dopamine release were chloride-free media and high extracellular K+; in particular, kainic acid and glutamate itself were ineffective. These results suggest that the primary neuronal chain mediating dopamine release in the turtle retina is: cone --> hyperpolarizing bipolar cell --> GABAergic amacrine cell --> dopaminergic amacrine cell.