Different sensitivities to external ATP in passive permeability of transformed mouse cell lines

External ATP causes a passive permeability change in several transformed cells but not in untransformed mouse fibroblasts. In the present experiments, the ATP-specific permeability change was observed also in B16 melanoma and L929 cells. The sensitivity to external ATP of these cells increased further when the concentration of intracellular ATP was lowered by addition of a mitochondrial inhibitor. In contrast, mouse 3T3 cells transformed by murine sarcoma virus did not respond to external ATP even when the intracellular ATP was depleted. Such differences in the ATP-sensitivity were not ascribed to the different concentrations of intracellular ATP.