Cenedese Valentina, de Graaff Wim, Csikós Tamás, Poovayya Mitali, Zoidl Georg, Kamermans Maarten
Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, Netherlands.
Department of Biology, York University, Toronto, ON, Canada.
Front Mol Neurosci. 2017 Dec 7;10:403. doi: 10.3389/fnmol.2017.00403. eCollection 2017.
Retinal horizontal cells (HCs) feed back negatively to cone photoreceptors and in that way generate the center/surround organization of bipolar cell receptive fields. The mechanism by which HCs inhibit photoreceptors is a matter of debate. General consensus exists that horizontal cell activity leads to the modulation of the cone Ca-current. This modulation has two components, one fast and the other slow. Several mechanisms for this modulation have been proposed: a fast ephaptic mechanism, and a slow pH mediated mechanism. Here we test the hypothesis that the slow negative feedback signal from HCs to cones is mediated by Panx1 channels expressed at the tips of the dendrites of horizontal cell. We generated zebrafish lacking Panx1 and found that the slow component of the feedback signal was strongly reduced in the mutants showing that Panx1 channels are a fundamental part of the negative feedback pathway from HCs to cones.
视网膜水平细胞（HCs）对锥状光感受器进行负反馈，从而形成双极细胞感受野的中心/外周组织。水平细胞抑制光感受器的机制一直存在争议。普遍的共识是，水平细胞的活动会导致锥状细胞钙电流的调制。这种调制有两个部分，一个快速部分和一个慢速部分。针对这种调制提出了几种机制：一种快速的电突触机制和一种慢速的pH介导机制。在这里，我们测试了这样一个假设，即从水平细胞到锥状细胞的慢速负反馈信号是由水平细胞树突尖端表达的Panx1通道介导的。我们培育出了缺乏Panx1的斑马鱼，发现突变体中反馈信号的慢速部分大幅减少，这表明Panx1通道是从水平细胞到锥状细胞的负反馈通路的基本组成部分。
