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The distribution of intermediate‐conductance, calcium‐activated, potassium (IK) channels in epithelial cells
Author(s) -
ThompsonVest Nichola,
Shimizu Yasutake,
Hunne Billie,
Furness John B.
Publication year - 2006
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2006.00515.x
Subject(s) - epithelium , myoepithelial cell , submucosal glands , biology , microbiology and biotechnology , respiratory epithelium , secretion , pathology , chemistry , endocrinology , medicine , immunology , immunohistochemistry
Abstract Intermediate‐conductance, calcium‐activated, potassium (IK) channels were first identified by their roles in cell volume regulation, and were later shown to be involved in control of proliferation of lymphocytes and to provide a K + current for epithelial secretory activity. Until now, there has been no systematic investigation of IK channel localization within different epithelia. IK channel immunoreactivity was present in most epithelia, where it occurred in surface membranes of epithelial cells. It was found in all stratified epithelia, including skin, cornea, oral mucosa, vaginal mucosa, urothelium and the oesophageal lining. It occurred in the ducts of fluid‐secreting glands, the salivary glands, lacrimal glands and pancreas, and in the respiratory epithelium. A low level of expression was seen in serous acinar cells. It was also found in other epithelia with fluid‐exchange properties, the choroid plexus epithelium, the ependyma, visceral pleura and peritoneum, bile ducts and intestinal lining epithelium. However, there was little or no expression in vascular endothelial cells, kidney tubules or collecting ducts, lung alveoli, or in sebaceous glands. It is concluded that the channel is present in surface epithelia (e.g. skin) where it has a cell‐protective role against osmotic challenge, and in epithelia where there is anion secretion that is facilitated by a K + current‐dependent hyperpolarization. It was also in some epithelial cells where its roles are as yet unknown.