Interactions of cone cannabinoid CB1 and dopamine D4 receptors increase day/night difference in rod-cone gap junction coupling in goldfish retina.
Interactions of cone cannabinoid CB1 and dopamine D4 receptors increase day/night difference in rod-cone gap junction coupling in goldfish retina.
复制标题
视锥大麻素CB 1和多巴胺D4受体的相互作用增加了金鱼视网膜视杆-视锥间隙连接耦联的昼夜差异
DOI：
10.1113/jp281308
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发表时间：
2021-09
期刊：
影响因子：
--
通讯作者：
Mangel SC
中科院分区：
文献类型：
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作者：
Cao J;Mangel SC
大麻素CB 1受体和多巴胺D4受体在大脑中形成相互作用的受体复合物，但这些相互作用在完整组织中的生理功能仍不清楚。在脊椎动物视网膜中，通过间隙连接连接的视杆细胞和视锥细胞表达CB 1和D4受体。由于视网膜昼夜节律钟使用视锥D4受体来减少白天的视杆-视锥间隙连接耦合，并在晚上增加它，我们研究了与单独作用的D4受体相比，视锥CB 1和D4受体之间的相互作用是否增加视杆-视锥耦合的日/夜差异。使用电记录和神经生物素示踪剂注射到完整的金鱼视网膜中的单个视锥细胞中，我们发现，SR 141716 A（CB 1受体拮抗剂）单独应用在白天增加了视锥细胞的视杆细胞-视锥细胞示踪剂偶联和视杆细胞输入的程度，视杆细胞通过开放的间隙连接到达视锥细胞。相反，在夜间单独应用SR 141716 A或在应用螺哌隆（一种D4受体拮抗剂）30分钟后的第二天应用SR 141716 A降低了视杆-视锥示踪剂偶联和视杆对视锥的输入。这些结果表明，内源性激活的锥CB 1受体减少杆锥耦合在白天时，D4受体被激活，但增加它在夜间时，D4受体未被激活。因此，D4受体依赖性的白天/黑夜开关的CB 1受体激活的影响，在杆锥耦合的白天/黑夜的差异增强的结果。这种协同作用增加了夜间对非常昏暗的大型物体的检测，以及白天对精细空间细节的检测。
Cannabinoid CB1 receptors and dopamine D4 receptors in the brain form receptor complexes that interact but the physiological function of these interactions in intact tissue remains unclear. In vertebrate retina, rods and cones, which are connected by gap junctions, express both CB1 and D4 receptors. Because the retinal circadian clock uses cone D4 receptors to decrease rod-cone gap junction coupling in the day and to increase it at night, we studied whether an interaction between cone CB1 and D4 receptors increases the day/night difference in rod-cone coupling compared to D4 receptors acting alone. Using electrical recording and injections of Neurobiotin tracer into individual cones in intact goldfish retinas, we found that SR141716A (a CB1 receptor antagonist) application alone in the day increased both the extent of rod-cone tracer coupling and rod input to cones, which reaches cones via open gap junctions. Conversely, SR141716A application alone at night or SR141716A application in the day following 30-min spiperone (a D4 receptor antagonist) application decreased both rod-cone tracer coupling and rod input to cones. These results show that endogenous activation of cone CB1 receptors decreases rod-cone coupling in the day when D4 receptors are activated but increases it at night when D4 receptors are not activated. Therefore, the D4 receptor-dependent day/night switch in the effects of CB1 receptor activation results in an enhancement of the day/night difference in rod-cone coupling. This synergistic interaction increases detection of very dim large objects at night and fine spatial details in the day.