# Serotonin Levels in IBS Pateins



## Kerri (Oct 1, 1999)

Patients with Constipation-Predominant Irritable Bowel Syndrome (IBS) May Have Elevated Serotonin Concentrations in Colonic Mucosa as Compared with Diarrhea-Predominant Patients and Subjects with Normal Bowel HabitsJun Miwaa, Hirotoshi Echizenb, Kei Matsuedaa, Noritsugu UmedaaaDivision of Gastroenterology, International Medical Center of Japan, Tokyo, and bDepartment of Pharmacotherapy, Meiji Pharmaceutical University, Tokyo, JapanDigestion 63:3:2001, 188-194.AbstractBackground: Serotonin (5-HT) may play an important role in the regulation of colonic motility in humans. However, it is not known whether alterations in the colonic 5-HT system are involved in the pathophysiology of irritable bowel syndrome (IBS). Methods: Colonic mucosal specimens ranging from the ascending colon to the rectum were obtained from patients with diarrhea- or constipation-predominant IBS (n = 7 and n = 8, respectively) and from subjects with normal bowel habits (n = 7) by endoscopic biopsy in order to determine whether patients with different clinical manifestations of IBS have different mucosal disposition of 5-HT. The tissue concentrations of 5-HT and its major metabolite, 5-hydroxyindoleacetic acid, were determined by reversed-phase high-performance liquid chromatography with fluorescence detection. Results: In all study groups, the mean mucosal 5-HT concentrations obtained from the rectum were significantly (p < 0.05) higher than those obtained from more cephalic regions of the colon. In addition, the overall mean mucosal 5-HT concentrations obtained from patients with constipation-predominant IBS were significantly (p < 0.05) higher than those obtained from the control subjects and patients with diarrhea-predominant IBS. No significant differences were observed in 5-hydroxyindoleacetic acid concentrations among the three groups. Conclusions: The mucosal 5-HT concentrations in the colon showed an ascending cephalocaudal gradient in all study groups. Although the mucosal 5-HT concentrations were elevated in patients with constipation-predominant IBS as compared with those with diarrhea-predominant IBS and the control subjects, further studies are necessary to determine whether the elevated mucosal 5-HT is a cause or a result of abnormal colonic motility.


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