title: Contribution of the IsK (MinK) potassium channel subunit to regulatory volume decrease in murine tracheal epithelial cells.
abstract: The cell volume regulatory response following hypotonic shocks is often achieved by the coordinated activation of K(+) and Cl(-) channels. In this study, we investigate the identity of the K(+) and Cl(-) channels that mediate the regulatory volume decrease (RVD) in ciliated epithelial cells from murine trachea. RVD was inhibited by tamoxifen and 1,9-dideoxyforskolin, two agents that block swelling-activated Cl(-) channels. These data suggest that swelling-activated Cl(-) channels play an important role in cell volume regulation in murine tracheal epithelial cells. Ba(2+) and apamin, inhibitors of K(+) channels, were without effect on RVD, while tetraethylammoniun had little effect on RVD. In contrast, clofilium, an inhibitor of the KvLQT/IsK potassium channel complex potently inhibited RVD, suggesting a role for the KvLQT/IsK channel complex in cell volume regulation by tracheal epithelial cells. To investigate further the role of KvLQT/IsK channels in RVD, we used IsK knock-out mice. When exposed to hypotonic solutions, tracheal cells from IsK(+/+) mice underwent RVD, whereas cells from IsK(-/-) failed to recover their normal size. These data suggest that the IsK potassium subunit plays an important role in RVD in murine tracheal epithelial cells.
authors.affiliation: Cell Signalling Unit, Department of Experimental Sciences, Universitat Pompeu Fabra, C/Dr. Aiguader 80, 08003 Barcelona, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Lock
authors.forename: M A
authors.initials: MA
authors.lastname: Valverde
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001030:Apamin / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D002923:Cilia / Q000187:drug effects; D005576:Colforsin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004594:Electrophysiology; D004847:Epithelial Cells / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D015221:Potassium Channels / Q000235:genetics* / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D013629:Tamoxifen / Q000494:pharmacology; D019789:Tetraethylammonium / Q000494:pharmacology; D013997:Time Factors; D014132:Trachea / Q000378:metabolism*
chemical_list: D000889:Anti-Arrhythmia Agents; D015220:Calcium Channels; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D000644:Quaternary Ammonium Compounds; C059983:potassium channel protein I(sk); D013629:Tamoxifen; D005576:Colforsin; D001030:Apamin; D001464:Barium; D019789:Tetraethylammonium; C022799:clofilium; C047983:1,9-dideoxyforskolin