Inhibitory effect of Ca(2+) antagonist on (45)Ca uptake by mast cells

(45)Ca uptake by rat peritoneal mast cells was observed, and the inhibitory effect of nifedipine, a Ca(2+) antagonist, on (45)Ca uptake by mast cells, stimulated by an antigen, comp. 48/80, concanavalin A and Ca ionophore A 23187, was examined. The increase in (45)Ca uptake by mast cells induced by the antigen paralleled the increase in mast cell number. A significant increase in the uptake of (45)Ca by mast cells was observed with the stimulation by the antigen, comp. 48/80, concanavalin A and Ca ionophore A 23187. The increased uptake of (45)Ca induced by antigen was inhibited by nifedipine, and this dose-dependent inhibitory effect of nifedipine on (45)Ca uptake was also observed in the mast cells stimulated by comp. 48/80, concanavalin A and Ca ionophore A 23187