Serotonin and its implication for the management of irritable bowel syndrome

Our understanding of the enteric nervous system (ENS) has evolved from the "classical" view, in which the brain controls all enteric behavior, to the current view, which holds that enteric innervation is one of local control within the bowel, modified by a bidirectional "dialogue" with the brain. The ENS independently controls enteric reflexes through intrinsic primary afferent neurons, which monitor intraluminal conditions. This monitoring is accomplished through the use of enteroendocrine cells in the mucosa, the best known of which are the serotonin-containing enterochromaffin cells. This article describes the roles that serotonin, specific serotonin-receptor subtypes, and the serotonin reuptake transporter play in the ENS and in the communication between the ENS and central nervous system. The way in which these findings have implicated serotonin in irritable bowel syndrome is discussed.