Institute of Physiology, Medical School, University of Pécs, Szigeti út 12, Pécs, 7624, Hungary.
Szentágothai Research Centre, University of Pécs, Pécs, 7624, Hungary.
Brain Struct Funct. 2019 Jul;224(6):2183-2197. doi: 10.1007/s00429-019-01876-y. Epub 2019 Jun 6.
Connexin-36 (Cx36) is the major constituent of mammalian retinal gap junctions positioned in key signal pathways. Here, we examined the laminar and large-scale topographical distribution of Cx36 punctate immunolabels in the retina of the cat, a classical model of the mammalian visual system. Calretinin-immunoreactive (CaR-IR) cell populations served to outline the nuclear and plexiform layers and to stain specific neuronal populations. CaR-IR cells included horizontal cells in the outer retina, numerous amacrine cells, and scattered cells in the ganglion cell layer. Cx36-IR plaques were found among horizontal cell dendrites albeit without systematic colocalization of the two labels. Diffuse Cx36 immunoreactivity was found in the cytoplasm of AII amacrine cells, but no colocalization of Cx36 plaques was observed with either the perikarya or the long varicose dendrites of the CaR-IR non-AII amacrine cells. Cx36 puncta were seen throughout the entire inner plexiform layer showing their highest density in the ON sublamina. The densities of AII amacrine cell bodies and Cx36 plaques in the ON sublamina were strongly correlated across a wide range of eccentricities suggesting their anatomical association. However, the high number of plaques per AII cell suggests that a considerable fraction of Cx36 gap junctions in the ON sublamina is formed by other cell types than AII amacrine cells drawing attention to extensive but less studied electrically coupled networks.
间隙连接蛋白 36（Cx36）是哺乳动物视网膜缝隙连接的主要成分，位于关键信号通路中。在这里，我们检查了猫视网膜中 Cx36 点状免疫标记的层状和大规模拓扑分布，猫是哺乳动物视觉系统的经典模型。钙调蛋白免疫反应性（CaR-IR）细胞群体用于勾勒核和神经丛层，并染色特定的神经元群体。CaR-IR 细胞包括外视网膜中的水平细胞、许多无长突细胞和神经节细胞层中的散在细胞。尽管没有两种标记物的系统共定位，但在水平细胞树突之间发现了 Cx36-IR 斑。在 AII 无长突细胞的细胞质中发现了弥散的 Cx36 免疫反应性，但未观察到 Cx36 斑与 CaR-IR 非 AII 无长突细胞的胞体或长静脉曲张突的共定位。Cx36 点状物可见于整个内神经丛层，在 ON 亚层中密度最高。在整个偏心范围内，AII 无长突细胞体和 Cx36 斑在 ON 亚层中的密度呈强相关性，表明它们具有解剖学关联。然而，每个 AII 细胞的斑数量很多，表明 ON 亚层中的相当一部分 Cx36 缝隙连接是由除 AII 无长突细胞以外的其他细胞类型形成的，这引起了人们对广泛但研究较少的电耦合网络的关注。
