Extracellular ATP induces rapid cell rounding in cultured human Chang liver cells

Extracellular ATP (7 microM-14 mM) induced monolayer Chang liver cells (ATCC CCL 13) to retract and round up in dose-dependent and time-dependent manners. ATP-induced rounding was concomitant with raised intracellular pH (7.3 to 7.8) and suppressed (a) in sodium-free medium (250 mM sucrose), (b) with the addition of 1 mM quinidine, an inhibitor of Na+/H+ exchanges, and (c) with the addition of 10 nM staurosporine, a potent inhibitor of protein kinase C that is known to activate Na+/H+ exchanges. These findings suggest that ATP-induced cell rounding is due to activation of Na+/H+ antiporters.