Effects of chloroquine on release of mediators from mast cells.

This study was designed to investigate the effect of chloroquine (CQ) on the release of preformed and generated mediators from rat serosal mast cells (greater than 90% pure). CQ alone (10-1,000 micrograms/ml) induced the release of preformed mediators, while stimulation with calcium ionophore A23187 of CQ-treated cells resulted in suppressed releases of both preformed and generated (particularly prostaglandin D2) mediators. These effects were calcium-independent and reversible. Whether these results partly explain the efficacy of CQ in the treatment of mast cell-mediated dermatoses remains to be further investigated.