Yoshiro Tanizaki

Inhibitory Effect of Nifedipine and Cromolyn Sodium on Skin Reactions and 45Ca Uptake and Histamine Release in Rat Mast Cells Induced by Various Stimulating Agents

The effect of nifedipine, one of the calcium channel antagonists, was examined in allergic and nonspecific reactions using rat skin and peritoneal mast cells. Rat passive cutaneous anaphylaxis response mediated by IgE antibody was inhibited by nifedipine (100 micrograms/rat) and also by cromolyn sodium (5 mg/rat). Skin reactions induced by histamine or methacholine were not inhibited, and skin reaction induced by serotonin was slightly inhibited by these drugs. The 45Ca uptake and histamine release in sensitized mast cells stimulated by ovalbumin were suppressed by nifedipine. In actively sensitized cells, nifedipine seems to be more effective on the inhibition of 45Ca uptake, but less effective on histamine release than cromolyn sodium. In mast cells, nonimmunologically stimulated by concanavalin A, compound 48/80, and calcium ionophore A23187, nifedipine exerted considerable inhibitory effects on both 45Ca and histamine release.

Effect of BSA on Ca2+ influx in mast cells stimulated by ovalbumin.

To examine the effect of bovine serum albumin (BSA) on the cell surface of mast cells, we measured 45Ca influx in mast cells from actively sensitized rats, and in cells passively sensitized in vitro with IgE-containing serum before or after BSA purification. Mast cells from actively sensitized rats showed a marked increase in 45Ca uptake after stimulation by ovalbumin. The uptake of 45Ca by mast cells passively sensitized before separation through BSA was also increased in response to ovalbumin. Variation in 45Ca uptake increased in the cells sensitized after separation. We did not observe a significant increase in 45Ca uptake in mast cells incubated with inactivated or normal serum compared to that of unstimulated cells.