THE RELATIONSHIP BETWEEN LIGHT, DOPAMINE RELEASE AND HORIZONTAL CELL COUPLING IN THE MUDPUPPY RETINA
THE RELATIONSHIP BETWEEN LIGHT, DOPAMINE RELEASE AND HORIZONTAL CELL COUPLING IN THE MUDPUPPY RETINA
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DOI：
10.1113/jphysiol.1991.sp018709
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发表时间：
1991-08-01
影响因子：
5.5
通讯作者：
MCREYNOLDS, JS
中科院分区：
文献类型：
--
作者：
DONG, CJ;MCREYNOLDS, JS
1. 通过比较不同实验条件对mudpuppy视网膜水平细胞间电耦合的影响，研究了中心点和环形刺激对感受野中心和周边部分照明反应的变化。 对中心点刺激的响应幅度的增加和对同心环的响应幅度的减少表明耦合的减少，反之亦然。 多巴胺（10-250 μ M）引起水平细胞之间的耦合减少。 多巴胺的解偶联作用在暗适应的视网膜中比在光适应的视网膜中大得多。 D1受体激动剂SKF 38393的作用与多巴胺相似。 D2受体激动剂LY 171555对偶联的影响与多巴胺相反;这归因于内源性多巴胺释放的减少。 D1拮抗剂SCH 23390（15 μ M）引起水平细胞之间的耦合增加。 这种效应在光适应的视网膜中比在暗适应的视网膜中大得多。 谷氨酸类似物2-氨基-4-膦酰基丁酸（APB），超极化的中心双极细胞，并阻止他们对光的反应，引起水平细胞之间的耦合增加。 APB的这种作用在光适应的视网膜中比在暗适应的视网膜中更大。 APB对偶联的影响可被多巴胺逆转，但不能被APB逆转。 这些结果表明，APB通过引起多巴胺释放的减少来增加水平细胞耦合。 在暗适应的视网膜，2.5分钟的适应光暴露引起水平细胞之间的耦合减少;在SCH 23390或APB的存在下，适应光的解耦合作用被阻断。 结果表明，mudpuppy视网膜水平细胞之间的耦合是由多巴胺作用于D1受体，多巴胺的释放影响水平细胞的光适应条件下更大，并通过暴露于光增加这种多巴胺释放的途径主要是通过对中心双极细胞。
1. The effect of different experimental conditions on electrical coupling between horizontal cells in the mudpuppy retina was studied by comparing the changes in responses to illumination of the central and peripheral portions of the receptive field, using centred spot and annulus stimuli. An increase in the amplitude of the response to a centred spot stimulus and a decrease in the amplitude of the response to a concentric annulus indicated a decrease in coupling, and vice versa.2. Dopamine (10-250-mu-M) caused a decrease in coupling between horizontal cells. The uncoupling effect of dopamine was much greater in dark-adapted than in light-adapted retinas. The effect of the D1-receptor agonist SKF38393 was similar to that of dopamine. The effect of the D2-receptor agonist LY171555 on coupling was opposite to that of dopamine; this was attributed to a reduction in endogenous dopamine release.3. The D1 antagonist SCH23390 (15-mu-M) caused an increase in coupling between horizontal cells. This effect was much greater in light-adapted than in dark-adapted retinas.4. The glutamate analogue 2-amino-4-phosphonobutyrate (APB), which hyperpolarizes on-centre bipolar cells and blocks their responses to light, caused an increase in coupling between horizontal cells. This effect of APB was greater in light-adapted retinas than in dark-adapted retinas. The effect of APB on coupling could be reversed by the addition of dopamine, but the effect of dopamine on coupling could not be reversed by the addition of APB. These results suggest that APB increases horizontal cell coupling by causing a decrease in dopamine release.5. In dark-adapted retinas, 2.5 min exposure to an adapting light caused a decrease in coupling between horizontal cells; the uncoupling effect of the adapting light was blocked in the presence of either SCH23390 or APB.6. The results suggest that coupling between horizontal cells in the mudpuppy retina is decreased by dopamine acting at D1 receptors, that the release of dopamine affecting horizontal cells is greater under light-adapted conditions, and that the pathway by which exposure to light increases this dopamine release is mainly via on-centre bipolar cells.