Serotonin and melatonin immunoreactivity in human gastrointestinal tract
Serotonin (5HT) is produced by gut enterochromaffin (EC) cells and is involved in the pathogenesis of neuromotor disorders that characterize functional and inflammatory gastrointestinal diseases. Melatonin is a synthetic product of both the vertebrate pineal gland and the EC cells of gastrointestinal tract (GIT). Both melatonin and serotonin share the same biosynthetic pathway from tryptophan, but their effects are almost antagonistic.