Swelling-activated potassium currents of Ehrlich ascites tumour cells.
The K+ and Cl- currents activated by Ca2+-ionophore treatment or by hypotonic cell swelling have been studied in Ehrlich ascites tumour cells by the patch-clamp technique. A charybdotoxin-inhibitable K+ current was activated by increasing intracellular Ca2+ concentration. In contrast, the K+ current activated by cell swelling was insensitive to charybdotoxin as well as to apamin, suggesting that channels different from those sensitive to Ca2+ are responsible for regulatory volume adjustments in these cells. The magnitude of the K+ and Cl- currents activated by hypotonic challenge was markedly temperature-dependent, possibly reflecting the temperature-dependence of enzymes involved in the intracellular signalling of cell volume regulation.
Riquelme
G
G
Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70058 Correo 7, Santiago, Chile.
Sepúlveda
F V
FV
Jørgensen
F
F
Pedersen
S
S
Hoffmann
E K
EK
D000818:Animals; D001030:Apamin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002286:Carcinoma, Ehrlich Tumor / Q000473:pathology / Q000503:physiopathology*; D048429:Cell Size; D018999:Charybdotoxin / Q000494:pharmacology; D018118:Chloride Channels / Q000502:physiology; D006096:Gramicidin / Q000494:pharmacology; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D008564:Membrane Potentials; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology*; D013696:Temperature; D014407:Tumor Cells, Cultured
D018118:Chloride Channels; D007476:Ionophores; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D018999:Charybdotoxin; D006096:Gramicidin; D001030:Apamin; D015759:Ionomycin; D002118:Calcium