Popova E, Kupenova P
Department of Physiology, Medical Faculty, Medical University, 1431 Sofia, Bulgaria.
Vision Res. 2011 Jul 15;51(14):1627-36. doi: 10.1016/j.visres.2011.05.005. Epub 2011 May 14.
The effect of dopamine D(1) receptor blockade by SCH 23390 on the V-logI function of the ERG b- and d-waves was investigated in dark and light adapted frog eyes. We obtained that the blocker enhanced the amplitude of the b- and d-waves in both conditions of adaptation. The enhancing effect of the blocker was more pronounced on the rod- than cone-dominated responses for the both ERG waves. The absolute sensitivity of the b-wave was not altered, but that of the d-wave was significantly increased. The intensity-response function of the b-wave, but not that of the d-wave, was shifted to the left along the intensity axis. The b-wave V-logI function had steeper slope and narrower dynamic range in both dark and light adapted eyes after the D(1) receptor blockade. The results obtained indicate that the endogenous dopamine, acting through D(1) receptors, does not play a crucial role in the process of retinal adaptation, although it changes in a specific manner the intensity-response function of both the ERG b- and d-waves.
研究了SCH 23390对多巴胺D(1)受体的阻断作用对暗适应和明适应青蛙眼睛视网膜电图（ERG）b波和d波的V-logI函数的影响。我们发现，在两种适应条件下，该阻断剂均增强了b波和d波的振幅。对于两种ERG波，该阻断剂对以视杆细胞为主的反应的增强作用比对以视锥细胞为主的反应更明显。b波的绝对敏感性未改变，但d波的绝对敏感性显著增加。b波的强度-反应函数沿强度轴向左移动，而d波的强度-反应函数未移动。在D(1)受体被阻断后，暗适应和明适应眼睛中的b波V-logI函数斜率更陡，动态范围更窄。所得结果表明，内源性多巴胺通过D(1)受体起作用，虽然它以特定方式改变了ERG b波和d波的强度-反应函数，但在视网膜适应过程中并不起关键作用。
