Serotonin induces melanogenesis via serotonin receptor 2A

Summary 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.