title: Non-selective cation and dysfunctional chloride channels in the apical membrane of nasal epithelial cells cultured from cystic fibrosis patients.
abstract: Chloride channels and non-selective cation channels in the apical membranes of cultured nasal epithelial cells from three cystic fibrosis patients were investigated with the patch-clamp technique. Outwardly rectifying chloride channels were found in 31% of the inside-out patches, but activity of this channel was never observed in cell-attached patches, even after stimulation with adrenaline. In 30% of the patches with chloride channels, activation occurred immediately after excision. Most of the channels, however, activated only after a membrane depolarization of +40 to +120 mV. Once activated, the chloride channels were indistinguishable from those in nasal epithelial cells of control patients. Amiloride-insensitive, calcium- and voltage-dependent, non-selective cation channels were present in 11% of the cell-attached and 43% of the cell-free patches and could not be distinguished from those in controls. The cystic fibrosis chloride channel defect is conserved in cultured nasal epithelial cells, while a non-selective cation channel is apparently not affected.
authors.affiliation: Center for Human Genetics, University of Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Jorissen
authors.forename: J
authors.initials: J
authors.lastname: Vereecke
authors.forename: E
authors.initials: E
authors.lastname: Carmeliet
authors.forename: H
authors.initials: H
authors.lastname: Van den Berghe
authors.forename: J J
authors.initials: JJ
authors.lastname: Cassiman
mesh_terms: D000293:Adolescent; D000328:Adult; D000584:Amiloride / Q000378:metabolism; D001693:Biological Transport, Active; D002412:Cations / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D018118:Chloride Channels; D003550:Cystic Fibrosis / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000378:metabolism*; D009296:Nasal Cavity / Q000378:metabolism*
chemical_list: D002412:Cations; D018118:Chloride Channels; D008565:Membrane Proteins; D000584:Amiloride