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

点击翻译按钮获取中文摘要

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.