Heterogeneity of 5‐HT Receptors Mediating Secretion in the Human Intestinea

: In conclusion, application of 5-HT has been shown to induce fluid secretion in both the small and large intestine of man. By the use of selective antagonists, the receptors mediating these effects have been identified and characterized. 5-HT induces secretion across human ileal mucosa via a receptor of the 5-HT4 sub-type, whereas a receptor of the 5-HT2A sub-type appears to mediate the effect in human sigmoid colon. The response in human ascending colonic mucosa cannot be definitively classified at this time, but may reflect the presence of a heterogenous receptor population.