Serotonin induces melanogenesis via serotonin receptor 2A

Background Serotonin (5-hydroxytryptamine, 5-HT) levels are increased by light exposure but the role and mechanism of 5-HT in the pigmentation of skin cells are unclear. Objectives To clarify the effect of 5-HT on melanogenesis and to determine the 5-HT receptor subtype involved. Methods B16F10, SK-MEL-2 and Melan-A cells were cultured in Dulbecco's modified Eagle's medium with low fetal bovine serum. The three cell lines were treated with various concentrations of 5-HT, and 5-HT receptor agonists and antagonists. The involvement of the 5-HT receptor 2A (5-HTR2A) was examined by gene silencing and use of 5-HTR2A antagonists. Results 5-HT and the 5-HTR2A agonist, DOI, increased melanogenesis in the three cell lines. These increased events were suppressed by 5-HTR2A antagonists or gene silencing of the HTR2A gene. Conclusions 5-HTR2A is involved in melanogenesis. These findings highlight the role of 5-HT and suggest new ways of controlling melanogenesis.