Intraretinal signaling by ganglion cell photoreceptors to dopaminergic amacrine neurons
Intraretinal signaling by ganglion cell photoreceptors to dopaminergic amacrine neurons
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DOI：
10.1073/pnas.0803893105
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发表时间：
2008-09-16
影响因子：
11.1
通讯作者：
McMahon, Douglas G.
中科院分区：
文献类型：
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作者：
Zhang, Dao-Qi;Wong, Kwoon Y.;McMahon, Douglas G.
视网膜多巴胺能无长突神经元（DA神经元）在根据普遍的照明条件重构视网膜功能中起核心作用，但光调节其活性的机制知之甚少。我们调查的手段，持续的光反应引起DA神经元。持续的光响应由阳离子电流驱动，并在体外和体内存在下持续存在：L-AP 4，视网膜ON-双极细胞的阻断剂。其中的几个特点。L-AP 4抗性光反应表明，它们是由表达黑视素的固有光敏视网膜神经节细胞（ipRGC）驱动的，包括长潜伏期、显著的刺激后持续性和478 nm的峰值光谱灵敏度。此外，持续的DA神经元光反应，但不是短暂的DA神经元反应，坚持在杆/锥退化视网膜，其中ipRGC占几乎所有剩余的视网膜光转导。因此，神经节细胞的光感受器提供兴奋驱动DA神经元，最有可能的方式，其树突的coramification和DA神经元的过程中的内丛状层。视网膜内神经节细胞信号的这种前所未有的离心外流为光重建视网膜回路提供了新的基础。
Retinal dopaminergic amacrine neurons (DA neurons) play a central role in reconfiguring retinal function according to prevailing illumination conditions, yet the mechanisms by which light regulates their activity are poorly understood. We investigated the means by which sustained light responses are evoked in DA neurons. Sustained light responses were driven by cationic currents and persisted in vitro and in vivo in the presence of: L-AP4, a blocker of retinal ON-bipolar cells. Several characteristics of these. L-AP4-resistant light responses suggested that they were driven by melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), including long latencies, marked poststimulus persistence, and a peak spectral sensitivity of 478 nm. Furthermore, sustained DA neuron light responses, but not transient DA neuron responses, persisted in rod/cone degenerate retinas, in which ipRGCs account for virtually all remaining retinal phototransduction. Thus, ganglion-cell photoreceptors provide excitatory drive to DA neurons, most likely by way of the coramification of their dendrites and the processes of DA neurons in the inner plexiform layer. This unprecedented centrifugal outflow of ganglion-cell signals within the retina provides a novel basis for the restructuring of retinal circuits by light.