Serotonin 5hydroxytryptamine

The majority of 5-hydroxytryptamine (5-HT) in the body is found in the gastrointestinal tract, primarily contained within enterochromaffin cells and is released by meals, toxins, and che-motherapeutic agents (161,162). 5-HT is implicated in postinfectious IBS patients by increased numbers of enterochromaffin cells (163), increased mast cell populations (15,164), increased postprandial 5-HT release (162,165), and a decrease in symptoms using serotonergic antagonists (1,166). Metabolism of 5-HT may also be disrupted in both IBS and IBD (167). 5-HT release is well known to activate vagal afferent endings in the upper gastrointestinal tract (168-170). 5-HT also activates cutaneous nociceptive primary afferents contributing to a role in inflammatory pain (171). More recently it was shown that rat colonic LSN afferents also respond to 5-HT (77). Fifty-six percent of LSN afferents responded to 5-HT via both 5-HT3 and non-5-HT3 receptors, which correlates with the percentage of thoracolumbar DRG cell bodies retrogradely labeled from the colon that display 5-HT3 receptors (77). In the rat 5-HT1, 5-HT2 and 5-HT3 receptor subtypes have been demonstrated to modulate responses to noxious colorectal distension (172), and serotonergic activation of visceral sensory neurons may increase their sensitivity to other sensory modalities (158).

Was this article helpful?

0 0

Post a comment