ACTIVATION OF A D2 RECEPTOR INCREASES ELECTRICAL COUPLING BETWEEN RETINAL HORIZONTAL CELLS BY INHIBITING DOPAMINE RELEASE
ACTIVATION OF A D2 RECEPTOR INCREASES ELECTRICAL COUPLING BETWEEN RETINAL HORIZONTAL CELLS BY INHIBITING DOPAMINE RELEASE
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DOI：
10.1073/pnas.89.19.9220
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发表时间：
1992-10-01
影响因子：
11.1
通讯作者：
MANGEL, SC
中科院分区：
文献类型：
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作者：
HARSANYI, K;MANGEL, SC
在鱼的视网膜中，丛状细胞将多巴胺释放到视锥细胞驱动的水平细胞上。多巴胺通过多巴胺 D1 受体激活腺苷酸环化酶，从而减少水平细胞之间的电耦合。利用细胞内记录，我们研究了多巴胺 D2 受体激活对完整金鱼视网膜中水平细胞电耦合的影响。 D2 激动剂 LY171555（喹吡罗；0.2-10 μM）的灌注增加了水平细胞耦合，如对中心光点或光缝的反应减少所示。水平细胞网络的长度常数平均增加了31%。尽管多巴胺 (0.5-20 μM) 使水平细胞解偶联，但较低浓度（例如 0.2 μM）最初解偶联，然后随后增加耦合超出初始控制水平。 LY171555 (10 muM) 的偶联效应可通过预先应用饱和 (20 muM) 或非饱和 (2.5-5.0 muM) 剂量的 D1 激动剂 SKF 38393 完全阻断。先前用 6-羟基多巴胺处理视网膜，破坏了多巴胺能神经元，消除了 LY171555 的偶联效应，但没有消除 SKF 38393 的解偶联效应。这些结果表明，金鱼水平细胞含有 D1 受体，但不含有 D2 受体，并且丛状细胞上 D2 自身受体的多巴胺激活抑制多巴胺释放到水平细胞上，从而水平细胞之间的电耦合增加。
In the fish retina, interplexiform cells release dopamine onto cone-driven horizontal cells. Dopamine decreases the electrical coupling between horizontal cells by activating adenylate cyclase through dopamine D1 receptors. Using intracellular recording, we have studied the effect of dopamine D2 receptor activation on horizontal cell electrical coupling in the intact goldfish retina. Superfusion of the D2 agonist LY171555 (quinpirole; 0.2-10 muM) increased horizontal cell coupling, as indicated by a decrease in responses to centered spots or slits of light. The length constant of the horizontal cell network increased an average of 31 %. Although dopamine (0.5-20 muM) uncoupled horizontal cells, lower concentrations (e.g., 0.2 muM) initially uncoupled and then subsequently increased coupling beyond initial control levels. The coupling effect of LY171555 (10 muM) was blocked completely by prior application of the D1 agonist SKF 38393 at saturating (20 muM) or nonsaturating (2.5-5.0 muM) doses. Prior treatment of the retinas with 6-hydroxydopamine, which destroyed dopaminergic neurons, eliminated the coupling effect of LY171555 but not the uncoupling effect of SKF 38393. These results suggest that goldfish horizontal cells contain D1, but not D2, receptors and that dopamine activation of D2 autoreceptors on interplexiform cells inhibits dopamine release onto horizontal cells so that the electrical coupling between horizontal cells increases.