Catecholamines in murine bone marrow derived mast cells

Cultured murine bone marrow derived mast cells (BMMC) were found to store high levels of dopamine (3753+/-844 pg/10(7) cells) and occasionally produce norepinephrine and epinephrine. The catecholamine synthesis inhibitor, alpha-methyl-para-tyrosine, decreased intracellular catecholamine concentrations, and activation with ionomycin stimulated dopamine release. Neither dopaminergic receptor antagonists nor exogenous dopamine < or =10 microM affected IL-3-induced cell proliferation. High exogenous dopamine (20-100 microM) decreased proliferation and increased apoptosis, and the anti-oxidant ascorbic acid prevented these effects. Increased expression of the anti-apoptotic factor Bcl-2 or loss of pro-apoptotic Bax expression attenuated dopamine-induced apoptosis, suggesting the apoptosis proceeds through a mitochondrial pathway.