Localization of ATP-sensitive K^+ channel in neuron, glial cells, and uriniferous epithelial cells.

ATP敏感性K^+通道属于内向整流性K^+通道家族，在维持细胞膜负电位、控制细胞体积和K^+分泌等方面具有重要作用。Kir6.1广泛存在于各种器官中，而Kir6.2则存在于胰腺β细胞和其他器官中。本实验采用原位杂交和免疫组织化学方法研究了Kir6.1和Kir6.2在脑内的定位。Kir6.1和Kir6.2在大多数神经元群体中广泛表达。在免疫电镜中，Kir6.1定位于线粒体中（Molecular Brain Research，74，15-25，1999），而Kir6.2定位于内质网和高尔基体中。此外，Kir6.1和Kir6.2在胼胝体和小脑白色物质中的神经胶质细胞中表达。在免疫电镜下，这些胶质细胞是星形胶质细胞和少突胶质细胞。然后，我们观察到mRNA的SURs，这些通道的调节亚基，在大多数神经元和胼胝体和小脑白色物质的胶质细胞。这些通道分子可能在神经元和神经胶质细胞中发挥重要作用。SURs的蛋白质及其亚细胞定位，以及在肾小管上皮细胞中的表达正在研究中。

ATP-sensitive K^+ channel, which belongs to inwardly rectifying K^+ channel family, have important roles such as maintenance of negative membrane potential, control of cellular volume, and K^+ secretion. Kir6.1 is localized ubiquitously in various organ, while Kir6.2 is localized in pancreatic β cells and other organ. These channel subunis form heteromultimer with sulphonylurea receptors (SUR), which are regulatory subunits of this channel.We investigated localization of Kir6.1 and Kir6.2 in brain by in situ hybridization and immunohistochemistry. Kir6.1 and Kir6.2 are widely expressed in most neuronal population. In immunoelectron microscopy Kir6.1 is localized in mitochondria (Molecular Brain Research, 74, 15-25, 1999), while Kir6.2 in endoplasmic reticulum and Golgi apparatus. In addition, Kir6.1 and Kir6.2 are expressed in glial cells in corpus callosum and in cerebellar white matter. In immunoelecton microscopy these glial cells are astrocytes and oligodendrocytes. We then observed mRNA for SURs, regulatory subunits of these channel, in most neurons and in glial cells of corpus callosum and cerebellar white matter. These channel molecules may play fundamental roles in neurons and in glial cells. Protein for SURs and their subcellular localization, as well as expression in uriniferous tubular epithelial cells, are being investigated.