Lee Seunghoon, Chen Lujing, Chen Minggang, Ye Meijun, Seal Rebecca P, Zhou Z Jimmy
Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA.
Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA; Zhiyuan College, Shanghai Jiao Tong University, Shanghai 200240, China.
Neuron. 2014 Nov 19;84(4):708-15. doi: 10.1016/j.neuron.2014.10.021. Epub 2014 Nov 6.
In the vertebrate retina, glutamate is traditionally thought to be released only by photoreceptors and bipolar cells to transmit visual signals radially along parallel ON and OFF channels. Lateral interactions in the inner retina are mediated by amacrine cells, which are thought to be inhibitory neurons. Here, we report calcium-dependent glutamate release from vGluT3-expressing amacrine cells (GACs) in the mouse retina. GACs provide an excitatory glutamatergic input to ON-OFF and ON direction-selective ganglion cells (DSGCs) and a subpopulation of W3 ganglion cells, but not to starburst amacrine cells. GACs receive excitatory inputs from both ON and OFF channels, generate ON-OFF light responses with a medium-center, wide-surround receptive field structure, and directly regulate ganglion cell activity. The results reveal a functional glutamatergic circuit that mediates noncanonical excitatory interactions in the retina and probably plays a role in generating ON-OFF responses, crossover excitation, and lateral excitation.
在脊椎动物视网膜中，传统观点认为谷氨酸仅由光感受器和双极细胞释放，以沿平行的ON和OFF通道径向传递视觉信号。视网膜内层的横向相互作用由无长突细胞介导，这些细胞被认为是抑制性神经元。在此，我们报道了小鼠视网膜中表达vGluT3的无长突细胞（GACs）依赖钙的谷氨酸释放。GACs为ON-OFF和ON方向选择性神经节细胞（DSGCs）以及W3神经节细胞的一个亚群提供兴奋性谷氨酸能输入，但不向星爆无长突细胞提供。GACs从ON和OFF通道接收兴奋性输入，产生具有中-心、宽-周边感受野结构的ON-OFF光反应，并直接调节神经节细胞的活动。这些结果揭示了一个功能性谷氨酸能回路，该回路介导视网膜中非典型的兴奋性相互作用，可能在产生ON-OFF反应、交叉兴奋和横向兴奋中发挥作用。
