School of Medicine, Western Sydney University, Goldsmith Avenue, Sydney NSW 2560, Australia.
Department of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Curr Biol. 2019 Mar 4;29(5):763-774.e5. doi: 10.1016/j.cub.2019.01.042. Epub 2019 Feb 21.
Retinal dopamine is released by a specialized subset of amacrine cells in response to light and has a potent influence on how the retina responds to, and encodes, visual information. Here, we address the critical question of which retinal photoreceptor is responsible for coordinating the release of this neuromodulator. Although all three photoreceptor classes-rods, cones, and melanopsin-containing retinal ganglion cells (mRGCs)-have been shown to provide electrophysiological inputs to dopaminergic amacrine cells (DACs), we show here that the release of dopamine is defined only by rod photoreceptors. Remarkably, this rod signal coordinates both a suppressive signal at low intensities and drives dopamine release at very bright light intensities. These data further reveal that dopamine release does not necessarily correlate with electrophysiological activity of DACs and add to a growing body of evidence that rods define aspects of retinal function at very bright light levels.
视网膜多巴胺是由特定的无长突细胞亚群在光刺激下释放的，对视网膜如何响应和编码视觉信息具有强大的影响。在这里，我们解决了一个关键问题，即哪种视网膜光感受器负责协调这种神经调质的释放。尽管所有三种光感受器（视杆细胞、视锥细胞和含有黑视蛋白的视网膜神经节细胞）都被证明可以向多巴胺能无长突细胞（DAC）提供电生理输入，但我们在这里表明，多巴胺的释放仅由视杆细胞决定。值得注意的是，这种视杆细胞信号不仅在低强度下协调抑制信号，而且在非常强的光强度下驱动多巴胺释放。这些数据进一步表明，多巴胺的释放并不一定与 DAC 的电生理活动相关，并且越来越多的证据表明，视杆细胞在非常强的光水平下定义了视网膜功能的某些方面。
