Prenatal alcohol exposure reduces 5-HT concentration in mouse intestinal muscle and mucosa

The influence of prenatal alcohol exposure on the serotoninergic system in the brain has been well studied, however its influence on the serotoninergic system in the gastrointestinal system remains unknown. The objective of the study was to use a mouse model of prenatal alcohol exposure to investigate the effects on serotonin and its metabolites and precursors in colonic tissue. This study used treatment of mouse breeding harems with 5% ethanol with saccharin via drinking water throughout pregnancy and compared the results with a saccharin control group. Tryptophan, serotonin (5-HT) and 5- hydroxyindoleacetic acid (5-HIAA) concentrations were measured in the longitudinal muscle myenteric plexus (LMMP) and mucosa of intestinal tissue by high-performance liquid chromatography (HPLC). Decreased 5-HT concentrations in mucosa and LMMP (females only) were observed in prenatally exposed mice compared to controls. Increases in mucosal and LMMP tryptophan concentration were only observed in prenatally exposed female mice. In conclusion, prenatal alcohol exposure causes a decrease in conversion of tryptophan to 5-HT in both muscle and mucosa although the effect is more pronounced in females. The observed sex difference may be related to changes associated with the estrous cycle.