Dopamine mediates circadian clock regulation of rod and cone input to fish retinal horizontal cells
Dopamine mediates circadian clock regulation of rod and cone input to fish retinal horizontal cells
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DOI：
10.1113/jphysiol.2002.023671
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发表时间：
2002-11-01
影响因子：
5.5
通讯作者：
Mangel, SC
中科院分区：
文献类型：
--
作者：
Ribelayga, C;Wang, Y;Mangel, SC
昼夜节律（24小时）时钟调节鱼锥体水平细胞的光反应，视网膜上的二级神经元接受来自锥体而不是杆状细胞的突触接触。由于时钟的作用，锥体水平细胞在白天由锥体驱动，但在晚上主要由杆状细胞驱动。我们在这里展示了多巴胺，一种视网膜神经递质，通过增加锥体水平细胞的锥体输入和减少杆状细胞的输入，作为一天的码头信号。体外视网膜内源性多巴胺释放量在主观白天大于主观夜晚。多巴胺或喹匹罗（一种多巴胺d -2样激动剂）在主观夜间的应用增加了锥细胞的输入，消除了杆状细胞的输入，这种状态通常在主观白天观察到。相比之下，在主观日期间，使用d -2样拮抗剂spiperone或腺苷酸环化酶活化剂forskolin可减少锥体输入并增加杆输入。SCH23390，一种D-1拮抗剂，没有效果。在夜间应用r -p- camp（一种camp依赖性蛋白激酶抑制剂）或辛醇（一种使间隙连接不偶联的醇），会增加锥体输入，减少杆输入。由于d -2样受体位于感光细胞上，而不是水平细胞上，因此结果表明，生物钟诱导的白天多巴胺释放增加激活了感光细胞上的d -2样受体。由此产生的细胞内环AMP和蛋白激酶A激活的减少介导锥体输入的增加和杆状输入的减少。
A circadian (24-hour) clock regulates the light responses of fish cone horizontal cells, second order neurones in the retina that receive synaptic contact from cones and not from rods. Due to the action of the clock, cone horizontal cells are driven by cones in the day, but primarily driven by rods at night. We show here that dopamine, a retinal neurotransmitter, acts as a dock signal for the day by increasing cone input and decreasing rod input to cone horizontal cells. The amount of endogenous dopamine released from in vitro retinae was greater during the subjective day than the subjective night. Application of dopamine or quinpirole, a dopamine D-2-like agonist, during the subjective night increased cone input and eliminated rod input to the cells, a state usually observed during the subjective day. In contrast, application of spiperone, a D-2-like antagonist, or forskolin, an activator of adenylyl cyclase, during the subjective day reduced cone input and increased rod input. SCH23390, a D-1 antagonist, had no effect. Application of R-p-cAMPS, an inhibitor of cAMP-dependent protein kinase, or octanol, an alcohol that uncouples gap junctions, during the night increased cone input and decreased rod input. Because D-2-like receptors are on photoreceptor cells, but not horizontal cells, the results suggest that the clock-induced increase in dopamine release during the day activates D-2-like receptors on photoreceptor cells. The resultant decrease in intracellular cyclic AMP and protein kinase A activation then mediates the increase in cone input and decrease in rod input.