The cystic fibrosis transmembrane conductance regulator (CFTR) inhibits ENaC through an increase in the intracellular Cl- concentration.
Activation of the CFTR Cl- channel inhibits epithelial Na+ channels (ENaC), according to studies on epithelial cells and overexpressing recombinant cells. Here we demonstrate that ENaC is inhibited during stimulation of the cystic fibrosis transmembrance conductance regulator (CFTR) in Xenopus oocytes, independent of the experimental set-up and the magnitude of the whole-cell current. Inhibition of ENaC is augmented at higher CFTR Cl- currents. Similar to CFTR, ClC-0 Cl- currents also inhibit ENaC, as well as high extracellular Na+ and Cl- in partially permeabilized oocytes. Thus, inhibition of ENaC is not specific to CFTR and seems to be mediated by Cl-.
König
J
J
School of Biomedical Sciences, Department of Physiology and Pharmacology, University of Queensland, St Lucia, Queensland 4072, Brisbane, Australia.
Schreiber
R
R
Voelcker
T
T
Mall
M
M
Kunzelmann
K
K
D000818:Animals; D002713:Chlorine / Q000378:metabolism* / Q000494:pharmacology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism* / Q000502:physiology*; D004594:Electrophysiology; D004847:Epithelial Cells / Q000378:metabolism; D053503:Epithelial Sodium Channels; D009865:Oocytes / Q000378:metabolism; D018075:RNA, Complementary / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000494:pharmacology; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000378:metabolism*; D014981:Xenopus
D053503:Epithelial Sodium Channels; D018075:RNA, Complementary; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D002713:Chlorine; D012964:Sodium