Micevych P E, Abelson L
Department of Anatomy and Cell Biology, UCLA School of Medicine 90024-1763.
J Comp Neurol. 1991 Mar 1;305(1):96-118. doi: 10.1002/cne.903050110.
The present study examined the distributions of connexin43 mRNA and connexin32 mRNA in the central nervous system (CNS) of the rat by using in situ hybridization histochemistry. These connexins are the best studied gap junction proteins; connexin32 forms direct cell-cell channels in the liver, as does connexin43 in the heart. There was a differential distribution of cells containing connexin32 mRNA compared with the population of cells which contained connexin43 mRNA, thus implying a regional specificity in the expression of connexins in the CNS. Cells containing connexin43 mRNA were uniformly distributed throughout the gray matter of the neuraxis. Several areas had a higher concentration of cells that express connexin43, such as layer IA of the piriform cortex, supraoptic and paraventricular nuclei of the hypothalamus, anterior cortical amygdaloid nucleus, the reticular part of the substantia nigra, lateral habenula, mesencephalic trigeminal nucleus. Purkinje cell layer of the cerebellum, facial nucleus, prepositus hypoglossal nucleus, and dorsal cochlear nucleus. The pattern of connexin43 hybridization and the morphology of connexin43 mRNA containing cells suggest that this gap junction forming protein is found predominantly in astrocytes. Connexin32 mRNA was detected in discrete cell groups of the gray matter that appeared to be neurons, including cells in layer 2 of the neocortex, layer II of the piriform cortex, pyramidal cell layer of the hippocampus, granule and polymorphic cell layers of the dentate gyrus, islands of Calleja, olfactory tubercle, lateral thalamic nuclei, lateral habenula, and Purkinje cell layer of the cerebellar cortex. A large population of cells in white matter tracts that were labelled with the connexin32 riboprobe appeared to be oligodendrocytes. These studies suggest that neurons and glial cells express connexin32 mRNA, but only astrocytes express connexin43 mRNA. Many of the areas in which connexin mRNAs were demonstrated have electrically coupled cells, morphologically distinct gap junction plaques, and/or have immunocytochemically identifiable connexin proteins. These results indicate that cells with mRNAs coding for intercellular channels have a widespread distribution in the mammalian CNS.
本研究采用原位杂交组织化学方法，检测了大鼠中枢神经系统（CNS）中连接蛋白43（connexin43）mRNA和连接蛋白32（connexin32）mRNA的分布。这些连接蛋白是研究得最为深入的间隙连接蛋白；连接蛋白32在肝脏中形成直接的细胞间通道，连接蛋白43在心脏中也如此。与含有连接蛋白43 mRNA的细胞群体相比，含有连接蛋白32 mRNA的细胞分布存在差异，这意味着中枢神经系统中连接蛋白的表达具有区域特异性。含有连接蛋白43 mRNA的细胞均匀分布于神经轴的整个灰质中。几个区域表达连接蛋白43的细胞浓度较高，如梨状皮质的IA层、下丘脑的视上核和室旁核、杏仁前皮质核、黑质网状部、外侧缰核、中脑三叉神经核、小脑浦肯野细胞层、面神经核、舌下前置核和蜗背侧核。连接蛋白43杂交模式以及含有连接蛋白43 mRNA的细胞形态表明，这种形成间隙连接的蛋白主要存在于星形胶质细胞中。在灰质中离散的细胞群中检测到连接蛋白32 mRNA，这些细胞群似乎是神经元，包括新皮质第2层的细胞、梨状皮质第II层的细胞、海马锥体细胞层、齿状回颗粒细胞层和多形细胞层、Calleja岛、嗅结节、外侧丘脑核、外侧缰核以及小脑皮质浦肯野细胞层。用连接蛋白32核糖探针标记的白质束中的大量细胞似乎是少突胶质细胞。这些研究表明，神经元和神经胶质细胞表达连接蛋白32 mRNA，但只有星形胶质细胞表达连接蛋白43 mRNA。许多显示有连接蛋白mRNA的区域存在电偶联细胞、形态学上不同的间隙连接斑，和/或具有免疫细胞化学可识别的连接蛋白。这些结果表明，编码细胞间通道的mRNA的细胞在哺乳动物中枢神经系统中广泛分布。
