The Netherlands Institute for Neuroscience, Department of Retinal Signal Processing, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
Brain Res. 2012 Dec 3;1487:25-38. doi: 10.1016/j.brainres.2012.04.059. Epub 2012 Jul 13.
Connexins are the building blocks of gap-junctions; sign conserving electrical synapses. Recently it has been shown that connexins can also function as hemichannels and can mediate a sign inverting inhibitory synaptic signal from horizontal cells to cones via an ephaptic mechanism. In this review we will discuss the critical requirements for such an ephaptic interaction and relate these to the available experimental evidence. The highly conserved morphological structure of the cone synapse together with a number of specific connexin proteins and proteoglycans present in the synaptic complex of the cones creates a synaptic environment that allows ephaptic interactions. The connexins involved are members of a special group of connexins, encoded by the GJA9 and GJA10 genes. Surprisingly, in contrast to many other vertebrates, mouse and other rodents seem to lack a GJA9 encoded connexin. The specific combination of substances that block feedback and the highly specific modification of feedback in a zebrafish lacking Cx55.5 hemichannels all point to an ephaptic feedback mechanism from horizontal cells to cones. This article is part of a Special Issue entitled Electrical Synapses.
连接蛋白是缝隙连接的结构基础，也是信号守恒的电突触。最近的研究表明，连接蛋白也可以作为连接小体，通过电突触机制介导水平细胞到视锥细胞的信号反转抑制性突触信号。在这篇综述中，我们将讨论这种电突触相互作用的关键要求，并将其与现有实验证据联系起来。视锥突触具有高度保守的形态结构，以及存在于视锥突触复合物中的一些特定连接蛋白和蛋白聚糖，为电突触相互作用创造了一个环境。涉及的连接蛋白是由 GJA9 和 GJA10 基因编码的特殊连接蛋白组的成员。令人惊讶的是，与许多其他脊椎动物相比，老鼠和其他啮齿动物似乎缺乏 GJA9 编码的连接蛋白。阻断反馈的特定物质组合以及缺乏 Cx55.5 连接小体的斑马鱼中反馈的高度特异性修饰都指向水平细胞到视锥细胞的电突触反馈机制。本文是题为“电突触”的特刊的一部分。
