title: Cl- and K+ conductances activated by cell swelling in primary cultures of rabbit distal bright convoluted tubules.
abstract: Ionic currents induced by cell swelling were characterized in primary cultures of rabbit distal bright convoluted tubule (DCTb) by the whole cell patch-clamp technique. Cl- currents were produced spontaneously by whole cell recording with an isotonic pipette solution or by exposure to a hypotonic stress. Initial Cl- currents exhibited outwardly rectifying current-voltage relationship, whereas steady-state currents showed strong decay with depolarizing pulses. The ion selectivity sequence was I- = Br- > Cl- >> glutamate. Currents were inhibited by 0.1 mM 5-nitro-2-(3-phenylpropylamino) benzoic acid and 1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid and strongly blocked by 1 mM diphenylamine-2-carboxylate. Currents were insensitive to intracellular Ca2+ but required the presence of extracellular Ca2+. They were not activated in cells pretreated with 200 nM staurosporine, 50 microM LaCl3, 10 microM nifedipine, 100 microM verapamil, 5 microM tamoxifen, and 50 microM dideoxyforskolin. Staurosporine, tamoxifen, verapamil, or the absence of external Ca2+ was without effect on the fully developed Cl- currents. Osmotic shock also activated K+ currents in Cl- free conditions. These currents were time independent, activated at depolarized potentials, and inhibited by 5 mM BaCl2. The activation of Cl- and K+ currents by an osmotic shock may be implicated in regulatory volume decrease in DCTb cells.
authors.affiliation: Unité Mixte de Recherche Centre National de la Recherche Scientifique, Université de Nice-Sophia Antipolis, Nice, France.
authors.forename: I
authors.initials: I
authors.lastname: Rubera
authors.forename: M
authors.initials: M
authors.lastname: Tauc
authors.forename: C
authors.initials: C
authors.lastname: Poujeol
authors.forename: M T
authors.initials: MT
authors.lastname: Bohn
authors.forename: M
authors.initials: M
authors.lastname: Bidet
authors.forename: G
authors.initials: G
authors.lastname: De Renzis
authors.forename: P
authors.initials: P
authors.lastname: Poujeol
mesh_terms: D000818:Animals; D000838:Anions / Q000378:metabolism; D001965:Bromides / Q000494:pharmacology; D048429:Cell Size; D002478:Cells, Cultured; D018118:Chloride Channels / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D007038:Hypotonic Solutions; D007686:Kidney Tubules, Distal / Q000166:cytology* / Q000502:physiology*; D007700:Kinetics; D008536:Meglumine / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D011817:Rabbits
chemical_list: D000838:Anions; D001965:Bromides; D018118:Chloride Channels; D002712:Chlorides; D007038:Hypotonic Solutions; D015221:Potassium Channels; D018698:Glutamic Acid; D008536:Meglumine