title: Amiloride-sensitive and HCO3(-)-dependent ion transport activated by aldosterone and vasotocin in A6 cells.
abstract: We studied the effects of aldosterone (Aldo) and arginine vasotocin (AVT) on ion transport of renal epithelial cell line (A6) by measuring short-circuit current (Isc). AVT induced a rapid, transient increase in Isc, followed by a decrease toward the baseline in cells untreated with Aldo. In cells treated with Aldo, Isc showed a biphasic response to AVT, i.e., both transient and sustained increases over 40 min after addition of AVT. The transient increase was composed only of amiloride-insensitive Isc regardless of Aldo treatment, whereas the sustained increase contained both amiloride-sensitive and amiloride-insensitive components. The main part of the amiloride-insensitive, sustained Isc depended on HCO3(-). In cells treated with Aldo for 1 day, removal of HCO3(-) in the bathing solution enhanced the amiloride-sensitive component and decreased the amiloride-insensitive one. These data suggest that 1) Aldo treatment is necessary for an AVT-induced sustained increase of Isc and 2) a HCO3(-)-dependent Isc mainly contributes to the sustained increase in amiloride-insensitive Isc.
authors.affiliation: Division of Respiratory Research, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Doi
authors.forename: Y
authors.initials: Y
authors.lastname: Marunaka
mesh_terms: D000450:Aldosterone / Q000494:pharmacology*; D000584:Amiloride / Q000494:pharmacology*; D001639:Bicarbonates / Q000494:pharmacology*; D002460:Cell Line; D004553:Electric Conductivity; D004848:Epithelium / Q000502:physiology; D007473:Ion Channels / Q000502:physiology*; D007668:Kidney / Q000502:physiology*; D007700:Kinetics; D014668:Vasotocin / Q000494:pharmacology*
chemical_list: D001639:Bicarbonates; D007473:Ion Channels; D000450:Aldosterone; D000584:Amiloride; D014668:Vasotocin