Pathways of Cl- transport in human fibroblasts.
Three pathways of Cl- efflux were identified in normal human fibroblasts. Twenty percent of the total Cl- efflux is via an electrically conductive pathway with an efflux constant of 0.016 min-1. This pathway is insensitive to 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and bumetanide but is partially inhibited by anthracene-9-carboxylic acid. Twenty-five percent of the Cl- efflux occurs via Cl- with cation cotransport having an efflux constant of 0.020 min-1. This pathway is inhibited by bumetanide and is dependent on the simultaneous presence of Na+, K+, and Cl-. Under basal conditions, the energetics of this pathway indicate that it is operating close to equilibrium. Fifty percent of the Cl- efflux occurs via an anion exchange pathway having an efflux constant of 0.040 min-1 that is inhibited by DIDS or by removal of Cl- from the extracellular medium. Together these pathways account for 95% of the total Cl- efflux.
Lin
P
P
Department of Biochemistry and Molecular Biology, University of Cincinnati College of Medicine, Ohio 45267-0522.
Gruenstein
E
E
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism; D027682:Cation Transport Proteins; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008433:Mathematics; D011188:Potassium / Q000378:metabolism; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D014634:Valinomycin / Q000494:pharmacology
D027682:Cation Transport Proteins; D002712:Chlorides; D014634:Valinomycin; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D012964:Sodium; D000251:Adenosine Triphosphatases; C022761:potassium transporting ATPase; D012413:Rubidium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium