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Visceral hypersensitivity in irritable bowel syndrome: evidence for involvement of serotonin metabolism – a preliminary study
Author(s) -
Keszthelyi D.,
Troost F. J.,
Jonkers D. M.,
Eijk H. M.,
Dekker J.,
Buurman W. A.,
Masclee A. A. M.
Publication year - 2015
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/nmo.12600
Subject(s) - irritable bowel syndrome , barostat , serotonergic , medicine , placebo , hyperalgesia , serotonin , visceral pain , gastroenterology , endocrinology , nociception , pathology , receptor , alternative medicine
Background Altered serotonergic (5‐ HT ) metabolism and visceral perception have been associated with the pathogenesis of irritable bowel syndrome ( IBS ). Aim of this preliminary study was to assess the effect of the direct precursor of 5‐ HT , 5‐hydroxytryptophan (5‐ HTP ), on systemic 5‐ HT metabolites and visceral perception and to assess potential differential responses between IBS and controls. Methods 15 IBS patients and 15 healthy volunteers participated in this randomized double‐blind placebo controlled study. Visceroperception was measured by rectal barostat. The 100 mg 5‐ HTP or placebo was ingested orally. Serotonergic metabolites were assessed in platelet poor plasma. Key Results 5‐ HTP induces rectal allodynia in a significant number of healthy controls; IBS patients exhibit lowered pain thresholds in both placebo and 5‐ HTP conditions. 5‐ HTP induces rectal hyperalgesia in hypersensitive but not in non‐hypersensitive IBS patients. Administration of 5‐ HTP significantly increased plasma 5‐ HTP levels ( p < 0.001), did not affect 5‐ HT levels ( p > 0.05), while levels of the main metabolite of 5‐ HT , 5‐hydroxyindoleacetic acid, increased significantly ( p < 0.05) in both groups. The magnitude of these changes observed in 5‐ HT metabolites was significantly greater in IBS patients. Conclusions & Inferences Oral administration of 5‐ HTP induced significant alterations in systemic 5‐ HT metabolites that were accompanied by increased visceroperception of pain in controls and hypersensitive IBS patients. Changes in 5‐ HT metabolism appear to be important factors involved in visceral hypersensitivity as the 5‐ HTP ‐induced pro‐nociceptive response was observed in all hypersensitive IBS patients and to a lesser magnitude in a significant number of healthy controls but in none of the non‐hypersensitive IBS patients.