An outwardly rectifying anion channel in human leukaemic K562 cells

In this study, an outwardly rectifying anion channel was characterized in the cell line K562 obtained from a chronic human leukaemia. Ion channel activity was recorded in the cell-detached (inside-out) configuration with standard patch-clamp technology. In most of the K562 cells studied, the channel exhibited low spontaneous activity, an outwardly rectifying current/voltage relationship and single-channel conductances of 19 pS and 40 pS for inwards and outwards currents respectively. The channel had a low permeability for gluconate with a relative permeability P(gluconate)/ P(Cl) of 0.14 and was blocked by glibenclamide (50 micro M) or diphenylamine-2-carboxylate (DPC, 1 mM) added to the cytoplasmic side of the patch. These results are characteristic of the outwardly rectifying Cl channel (ORCC) found in other types of cells.