title: Elevation of a potassium current in differentiating human leukemic (HL-60) cells.
abstract: Human promyelocytic leukemia (HL-60) cells display a novel voltage-dependent outward current under voltage clamp. This current is present at low levels in the proliferative state and in granulocytes derived from HL-60 cells which were induced to differentiate with retinoic acid. It is elevated in macrophages derived from HL-60 cells after exposure to phorbol-12-myristate-13-acetate (PMA). The current is carried primarily by K+, is blocked by Cs+ and by increased intracellular concentrations of Cl-. From a holding potential of -80 mV, significant activation required depolarization to +20 mV membrane potential. Activation was not influenced by intracellular Ca2+ (1-2 X 10(-6) M). These properties appear to differ significantly from the Ca2+-activated K+ channel and the delayed rectifier. The increase of this voltage-activated current in differentiation toward the macrophage, but not the granulocyte, suggests that this current is correlated specifically with macrophage differentiation.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation; D002460:Cell Line; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D004553:Electric Conductivity; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007951:Leukemia, Myeloid / Q000503:physiopathology*; D008264:Macrophages / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D002712:Chlorides; D007473:Ion Channels; D002586:Cesium; D014212:Tretinoin; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium; D002118:Calcium