Influence of autonomic neurotransmitters on human uveal melanocytes in vitro

The influence of autonomic neurotransmitters on the growth and melanogenesi s of cultured uveal melanocytes was studied. Uveal melanocytes were culture d with medium supplemented with cAMP elevating agents and basic fibroblast growth factor (complete medium). The cells were plated into multiple well p lates. and various concentrations of adrenergic and cholinergic agents were added to the media (complete medium or various deleted media). After 6 day s, the cells were detached for cell counting and melanin measurement and co mpared to controls. Epinephrine, isoproterenol, salbutamol and metaproteren ol (adrenergic agonists that can activate beta(2)-adrenoceptors) substantia lly stimulated growth and melanogenesis of cultured uveal melanocytes in cA MP-deleted medium. Methoxamine, clonidine, prenalterol and D-7114 (adrenerg ic agonists that do not activate beta(2)-adrenoceptors) showed no effect un der similar experimental conditions. Muscarine (a cholinergic agonist) inhi bited the growth and melanogenesis of uveal melanocytes in complete medium. It indicates that adrenergic agents (beta(2)-adrenoceptor agonists) stimul ate growth and melanogenesis in uveal melanocytes, while cholinergic agonis t has an inhibitory effect. This effect appears to involve the cAMP second messenger system. These studies suggest that homeostasis of the uveal melan ocytes may be maintained. in part. by regulating the autonomic nervous syst em in vivo. (C) 2000 Academic Press.