Ball A K, McReynolds J S
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
J Comp Neurol. 1998 Mar 30;393(1):48-57. doi: 10.1002/(sici)1096-9861(19980330)393:1<48::aid-cne5>3.0.co;2-q.
Physiological studies have demonstrated the existence of direct intercellular communication, presumably mediated by gap junctions, both between neurons and between glial cells in the vertebrate retina. We localized gap junctions in the retinas of rat, goldfish, and mudpuppy by using antisera directed against proteins that make up the connexon channels in two tissues from which connexins have been isolated: liver (connexin 32; CX32) and heart (connexin 43; CX43). Although the antiserum against CX32 stained liver gap junctions, it did not reveal any staining in rat or goldfish retina. The antiserum against CX43 stained gap junctions associated with the intercalated disk in rat heart and also stained gap junctions between pigment epithelium cells in rat, goldfish, and mudpuppy retina. Anti-CX43 also stained gap junctions between Müller cells in goldfish and mudpuppy retina but not in rat retina. Intracellular injections of the tracer Neurobiotin into Müller cells in the mudpuppy retina revealed that these glial cells are extensively tracer coupled. Staining with the tracer formed a syncytium of thin processes surrounding every neuron from the outer limiting membrane to the inner limiting membrane. Confocal microscopy demonstrated that the Müller cells were in close apposition with one another at every level of the retina. However, CX43 immunoreactivity was heaviest at the outer limiting membrane, where the apical processes of Müller cells are located. Some anti-CX43 staining was observed at the level of the outer nuclear layer and the inner plexiform layer but not in the ganglion cell layer or at the Müller cell end feet forming the inner limiting membrane.
生理学研究表明，在脊椎动物视网膜的神经元之间以及神经胶质细胞之间存在直接的细胞间通讯，推测是由缝隙连接介导的。我们通过使用针对构成连接子通道的蛋白质的抗血清，在大鼠、金鱼和泥螈的视网膜中定位缝隙连接。连接蛋白已从两种组织中分离出来：肝脏（连接蛋白32；CX32）和心脏（连接蛋白43；CX43）。尽管针对CX32的抗血清可染色肝脏的缝隙连接，但在大鼠或金鱼视网膜中未显示任何染色。针对CX43的抗血清可染色大鼠心脏闰盘相关的缝隙连接，也可染色大鼠、金鱼和泥螈视网膜色素上皮细胞之间的缝隙连接。抗CX43还可染色金鱼和泥螈视网膜中Müller细胞之间的缝隙连接，但在大鼠视网膜中未染色。向泥螈视网膜的Müller细胞内注射示踪剂Neurobiotin表明，这些神经胶质细胞广泛地进行示踪剂耦联。用示踪剂染色形成了一个由细突起组成的合胞体，从外限制膜到内限制膜围绕着每个神经元。共聚焦显微镜显示，Müller细胞在视网膜的各个层面都彼此紧密相邻。然而，CX43免疫反应性在外限制膜处最强，Müller细胞的顶端突起位于此处。在外核层和内网状层水平观察到一些抗CX43染色，但在神经节细胞层或形成内限制膜的Müller细胞终足处未观察到。
