Acid-sensitive outwardly rectifying anion channels in human erythrocytes.
Acid-sensitive outwardly rectifying anion channels (ASOR) have been described in several mammalian cell types. The present whole-cell patch-clamp study elucidated whether those channels are expressed in erythrocytes. To this end whole-cell recordings were made in human erythrocytes from healthy donors treated with low pH and high osmotic pressure. When the pipette solution had a reduced Cl(-) concentration, treatment of the cells with Cl(-)-containing normal and hyperosmotic (addition of sucrose and polyethelene glycol 1000 [PEG-1000] to the Ringer) media with low pH significantly increased the conductance of the cells at positive voltages. Channel activity was highest in the PEG-1000 media (95 and 300 mM PEG-1000, pH 4.5 and 4.3, respectively) where the current-voltage curves demonstrated strong outward rectification and reversed at -40 mV. Substitution of the Cl(-)-containing medium with Cl(-)-free medium resulted in a decrease of the conductance at hyperpolarizing voltages, a shift in reversal potential (to 0 mV) and loss of outward rectification. The chloride currents were inhibited by chloride channels blockers DIDS and NPPB (IC(50) for both was approximately 1 mM) but not with niflumic acid and amiloride. The observations reveal expression of ASOR in erythrocytes.
Kucherenko
Yuliya V
YV
Department of Physiology, University of Tübingen, Tübingen, Germany.
Mörsdorf
Daniel
D
Lang
Florian
F
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D065101:Chloride Channel Agonists; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009544:Niflumic Acid / Q000494:pharmacology; D009579:Nitrobenzoates / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011092:Polyethylene Glycols / Q000494:pharmacology; D013395:Sucrose / Q000494:pharmacology
D020533:Angiogenesis Inhibitors; D065101:Chloride Channel Agonists; D018118:Chloride Channels; D016861:Cyclooxygenase Inhibitors; D009579:Nitrobenzoates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D011092:Polyethylene Glycols; D009544:Niflumic Acid; D013395:Sucrose; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid