Nadarajah B, Thomaidou D, Evans W H, Parnavelas J G
Department of Anatomy and Developmental Biology, University College London, United Kingdom.
J Comp Neurol. 1996 Dec 9;376(2):326-42. doi: 10.1002/(SICI)1096-9861(19961209)376:2<326::AID-CNE13>3.0.CO;2-J.
Gap junctions are membrane channels that mediate electrical and metabolic coupling between adjacent cells. Immunocytochemical analysis by using a panel of anti-connexin antibodies, as well as electron microscopy of thin sections and freeze-fracture replicas, has shown that gap junctions and their constituent proteins are abundant in the cerebral cortex of the adult rat. Their frequency and distribution vary in different cortical regions, which may reflect differences in the cellular and functional organization of these areas of the cortex. Gap junctions were identified between glial cells and, less frequently, between neuronal elements. Heterologous junctions were also identified between astrocytes and oligodendrocytes and between neurons and glia; the latter category included abundant junctions between astrocytic processes and neurons. Double-antibody labelling experiments in tissue sections and in acutely dissociated cells showed that connexin 32 was expressed in neurons and oligodendrocytes, whereas connexin 43, widely believed to be expressed only in astrocytes, was also localized in a population of cortical neurons. These results show that gap junctions can provide a major nonsynaptic means of communication between cortical cell types.
缝隙连接是介导相邻细胞间电偶联和代谢偶联的膜通道。利用一组抗连接蛋白抗体进行的免疫细胞化学分析，以及超薄切片和冷冻断裂复制品的电子显微镜观察表明，缝隙连接及其组成蛋白在成年大鼠大脑皮质中含量丰富。它们在不同皮质区域的频率和分布有所不同，这可能反映了皮质这些区域细胞和功能组织的差异。在胶质细胞之间发现了缝隙连接，在神经元成分之间发现的频率较低。在星形胶质细胞和少突胶质细胞之间以及神经元和胶质细胞之间也发现了异源连接；后一类包括星形胶质细胞突起与神经元之间大量的连接。组织切片和急性解离细胞中的双抗体标记实验表明，连接蛋白32在神经元和少突胶质细胞中表达，而普遍认为仅在星形胶质细胞中表达的连接蛋白43也定位于一群皮质神经元中。这些结果表明，缝隙连接可以为皮质细胞类型之间提供一种主要的非突触通讯方式。
