ABSTRACT
Objective To observe the effects of rectal thermal- and pressure- stimuli on visceral perception thresholds in patients with irritable bowel syndrome (IBS) and investigate its pathogenesis. Methods Rectal visceral perception thresholds were examined in 46 patients with IBS and in 13 normal controls after rectal thermal- and pressure stimuli. Subjects were asked to report its sensation, location and spread. Results Compared with healthy subjects, IBS patients, especially those with diarrhea-predominant IBS, demonstrated significantly lower perception thresholds to rectal thermal and pressure stimuli. Ice had varied effects on symptoms in patients with IBS and no effects on perception thresholds. Conclusion Visceral perception thresholds were decreased significantly after rectal thermal-and pressure- stimuli in patients with IBS. Visceral hypersensitivity is one of the important pathogenesis in IBS.
ABSTRACT
Objective To investigate the possible role of mRNA expression of nitric oxide synthase in the abnormal intestinal motility and visceral perception in patients with diarrhea predominant IBS. Methods Anorectal manometry and rectal visceral sensory thresholds were examined in 25 patients with diarrhea predominant IBS and 15 healthy controls by means of electric barostat and perfusion catheter manometer. The quantity of NO was measured using nitrate/nitrite colorimetric assay. The nerve fibers containing NOS in mucosal muscular layer of colon was quantitatively measured with NADPH diaphorase histochemistry assay and computer image analysis. The expression of neuronal nitric oxide synthase (nNOS) mRNA was determined with fluorescence quantitative polymerase chain reaction (FQ PCR). Results Thresholds of first perception, defecation and pain in patients with IBS were significantly lower than those of controls. The motility indexes of sigmoid and rectum were significantly higher than those of normal controls ( P