Serotonin and 5-HT2B receptors in microglia control of behavior

Abstract Serotonin has been widely involved in neuropsychiatric diseases, including major depressive disorders, or schizophrenia, and in neurodegenerative diseases, including Alzheimer's disease or amyotrophic lateral sclerosis. Independent evidence also suggests the contribution of inflammatory mediators in these pathologies. Indeed, peripheral infections as well as chronic diseases of the central nervous system cause activation of microglia, the resident macrophages of the brain. Emerging evidence indicate that serotonin might regulate brain inflammation, either developmentally, acutely, or during neurodegenerative diseases, and in turn influence the course of these diseases. In this review, we summarize evidence for serotonin involvement via 5-HT2B receptors in inflammatory responses in the central nervous system. We show how microglial activation may participate in behavioral changes associated to pathologies including depression, psychosis, and neurodegenerative diseases.