Migrating motor complex in colectomized ileo stoma patients.

In colectomized patients with ileo stoma, the reflex modulation of small intestinal functions is disturbed, resulting in high enteric stoma outputs and malabsorption. Serotonin has a pivotal role in initiating motor and secretory reflexes involving activation of neuronal 5-HT(3) and smooth muscle muscarinic receptors. We aimed to evaluate the effect of 5-hydroxytryptamine (5-HT), ondansetron and atropine on fasting and stimulated antro-duodeno-jejunal migrating motor complex (MMC) in colectomized patients with ileo stoma compared with healthy subjects. Manometric recordings were obtained in a blinded, age- and gender-matched design. The effects of either standard meal or intravenous 5-HT (10 nmol/kg/min.) treatment with pre-treatment of saline (placebo) or ondansetron (250 μg/kg) or atropine (10 μg/kg) were compared. Adverse effects, blood pressure, heart rate and electrocardiographic data were also evaluated. 5-HT increased the frequency (threefold) and migration velocity (twofold) of MMC phase III in both experimental groups. Ondansetron reduced 5-HT-induced frequency of MMC phase III in patients (p < 0.05) but not in healthy subjects. Atropine reduced 5-HT-induced frequency of MMC phase III in healthy subjects (p < 0.05). Ondansetron did not alter fasting or postprandial MMC in either experimental group (p > 0.05). Atropine did not change fasting MMC in healthy subjects (p > 0.05). We conclude that 5-HT is a stimulator of MMC phase III and that ondansetron reduces the 5-HT-induced MMC phase III without affecting fasting or postprandial properties in colectomized patients with ileo stoma. Similar effects were observed for 5-HT and atropine in healthy subjects.