Placental serotonin systems in pregnancy metabolic complications associated with maternal obesity and gestational diabetes mellitus

Serotonin (5-hydroxytryptamine, 5-HT) regulates diverse physiological and behavioural and processes, also acts as a developmental signal in early embryogenesis and in regulation of fetal development. A number of studies have implicated the prominent role of serotonin transporter (SERT or 5-HTT) and 5-HT receptor subtypes in placental development and function. Here, in this article we have provided a comprehensive review on the important role of 5-HT homeostasis in pregnancy outcomes. More specifically, we have summarised the findings from experimental and clinical studies, the influence of maternal and placental inflammation associated with the gestational diabetes and obesity on placental serotonin synthesis, expression of SERT and 5-HT receptors and their activity. Understanding the molecular regulation of placental SERT and 5-HT receptors using selective pharmacological agonists or antagonists may identify the therapeutic potential of serotonin pathway to improve long-term health outcomes of mothers and her infants exposed to GDM and obesity.