The role of anions in cellular volume regulation.
Cellular volume can be varied substantially by replacing medium Cl- isosmotically by other univalent anions. Since K+ content changes in parallel, cellular K+ concentration is well maintained. Gluconate behaves as an impermeant anion so cells shrink. Acetate enters cells apparently by non-ionic diffusion causing marked cellular swelling. These changes in volume are fully reversed when Cl- is again restored to the medium. However, ouabain (10(-3) M) largely prevents this reversal when Cl- replaces acetate, arguing against a ouabain-insensitive volume regulating mechanism. In toad urinary bladder, serosal gluconate inhibits transepithelial Na+ transport and cells shrink. Analysis suggests that cell shrinkage results in a loss of Ba2+-sensitive highly selective basolateral membrane K+ conductance channels.
D000818:Animals; D000838:Anions; D001693:Biological Transport, Active / Q000187:drug effects; D002025:Bufonidae; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D004848:Epithelium / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D001743:Urinary Bladder / Q000378:metabolism; D014882:Water-Electrolyte Balance
D000838:Anions; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase