The important role of serotonin in gut function is well recognized. Release of serotonin from the basolateral membranes of enterochromaffin cells in the epithelial lining of the gut into the vicinity of afferent nerve endings represents the primary method of sensory transmission from the lumen of the gastrointestinal tract. Because this signaling mechanism involves secretion of large amounts of serotonin, the mechanism for the uptake of serotonin (via the serotonin reuptake transporter [SERT]) must be efficient.
In a recent issue of Gut, Astrid Yeo, PhD, and colleagues performed a genotypic analysis on 194 women with irritable bowel syndrome with diarrhea (IBS-D) and 448 controls. Results of polymerase chain reaction analysis examining 9 SERT polymorphisms, including the insertion/ deletion polymorphism in the SERT promoter (SERT-P) and the variable tandem repeat in intron 2, demonstrated a strong genotypic association between the SERT-P deletion/deletion genotype and the presence of IBS-D.