SWELLING-ACTIVATED POTASSIUM CURRENTS OF EHRLICH ASCITES TUMOR-CELLS

The K+ and Cl- currents activated by Ca2+-ionophore treatment or by hy potonic cell swelling have been studied in Ehrlich ascites tumour cell s by the patch-clamp technique. A charybdotoxin-inhibitable K+ current was activated by increasing intracellular Ca2+ concentration. In cont rast, the K+ current activated by cell swelling was insensitive to cha rybdotoxin as well as to apamin, suggesting that channels different fr om those sensitive to Ca2+ are responsible for regulatory volume adjus tments in these cells, The magnitude of the K+ and Cl- currents activa ted by hypotonic challenge was markedly temperature-dependent, possibl y reflecting the temperature-dependence of enzymes involved in the int racellular signalling of cell volume regulation. (C) 1998 Elsevier Sci ence B.V.