Effect of methylmercury on the rat mast cell degranulation

Methylmercury is the well-known neurotoxicant as well as a modulator of the immune system. We investigated the effects of MeHg on the rat mast cell degranulation induced by non-immunological stimuli (the selective liberator of histamine, compound 48/80, and calcium ionophore A23187) both in vivo and in vitro. In 8, 12 and 15 days after the final administration of MeHg we observed the suppression of calcium ionophore A23187- and 48/80-induced histamine release, which enhanced with time. In experiments in vitro incubation of peritoneal mast cells with MeHg alone in the dose range 10(-8) to 10(-6) did not induce mast cell degranulation, however modified the activation of mast cells by compound 48/80, and calcium ionophore A23187. We observed activation of stimulated secretion by preliminary incubation with low dose of MeHg 10(-8) M and inhibition by dose of MeHg 10(-6) M. These results show that MeHg treatment can modify mast cell function in vivo and in vitro and provide insight into the understanding what role this cell has in the pathogenesis of Minamata disease-connected disorders.