Peripheral serotonin regulates epidermal differentiation and dermal homeostasis

Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter with key peripheral functions, including regulation of vascular tone, immune responses, and tissue repair (Amireault et al, 2013). Over the past two decades, mammalian skin has been recognized as a peripheral neuroendocrine organ capable of locally synthesizing, metabolizing, and responding to 5-HT through coordinated expression of tryptophan hydroxylase (TPH1), monoamine oxidases (MAOA/B), the serotonin transporter (SERT/Slc6a4), and multiple 5-HT receptor subtypes (Slominski et al, 2005).