Role of Production and Degradation of Serotonin During Development

Abstract

Serotonin (5-hydroxytryptamine (5-HT)) is one of the major neurotransmitter in the brain. Since 5-HT is car- ried by 5-HT transporters and the biological activities of 5-HT are exerted through 5-HT receptors, disturbed regulation of 5-HT transporters and receptors in the adult brain has been implicated in pathological conditions in central nervous sys- tems. On the other hand, proper 5-HT neurotransmission during development underlies the mature functional architecture of serotonergic neurons, and an increasing body of evidence suggests the involvement of developmental brain distur- bances in psychiatric disorders. Genetic mouse models have shown that 5-HT receptors and the 5-HT transporter acting during developmental stages modulate developmental processes. In addition, recent works demonstrated that appropriate 5-HT production and 5-HT degradation during develoment are needed for the development of 5-HT neurons and brain functions in the adult. In this review article, we focus on the importance of activities of tryptophan hydroxylase (TPH), the rate-limiting enzyme in 5-HT biosynthesis and monoamine oxidase A (MAOA), a catabolic enzyme responsible for deg- radation of 5-HT during development for the brain functions in the adult.