Enteric and central contributions to intestinal dysmotility in irritable bowel syndrome

Abstract

The aim of the study was to further elucidate the pathophysiology of irritable bowel syndrome and its subgroups by examining and comparing alterations in small bowel motility, specifically phase II and phase III components of the migrating motor complex. Prolonged recordings of interdigestive small bowel motility were obtained during both diurnal and nocturnal periods in 20 patients with irritable bowel syndrome--10 with predominant constipation and 10 with predominant diarrhea--and in 10 healthy subjects. Diurnal amplitude (mean +/- SD) of phase III activity fronts was lower (P less than 0.05) in constipation-predominant patients (16.3 +/- 3.1 mm Hg) than in diarrhea-predominant patients (20.2 +/- 3.1) or controls (20.9 +/- 2.7). Similar findings were observed nocturnally. Phase III cycle length was also significantly prolonged diurnally in constipation-predominant patients when compared to the other groups. In the diarrhea-predominant group repetitive and rapidly propagated bursts of contractions were observed in eight patients, and this pattern occupied a significantly greater proportion of phase II motor activity than in controls. These alterations in phase II and in phase III components of the migrating motor complex suggest that both local (enteric) and more central mechanisms may operate to produce intestinal dysmotility in the irritable bowel syndrome and that these mechanisms differ according to the predominant alteration of bowel habit.

Characteristics of small bowel motility in patients with irritable bowel syndrome and normal humans: an Oriental study

“…Recent reports indicate that a disordered autonomic nervous system can in turn alter small bowel transit to elicit clinical symptoms [10,11]. Second, the altered small intestinal motor activity may contribute to the IBS symptoms since the diurnal or nocturnal amplitude of phase III activity of migrating motor complex is weak in constipated patients with IBS [12]. Moreover, the interval between two successive migrating motor complex cycles is short in diarrhoea patients with IBS [13].…”

Alterations of sensori-motor functions of the digestive tract in the pathophysiology of irritable bowel syndrome

“…61,63,64 In another study, the amplitude of contractions during phase III of the MMC was reduced and the overall duration of the MMC, prolonged among those with constipation-predominant IBS. 68 The most consistent abnormality recorded in patients with IBS is the occurrence of repetitive bursts of contractions at a regular rhythm and this pattern was in some patients related to the onset of pain. 63,64,68,69 This pattern, named minute rhythm, as bursts of contractions appear at a regular frequency of one/minute has however been observed in healthy volunteers and is thus not specific of IBS (Figure 4).…”

“…68 The most consistent abnormality recorded in patients with IBS is the occurrence of repetitive bursts of contractions at a regular rhythm and this pattern was in some patients related to the onset of pain. 63,64,68,69 This pattern, named minute rhythm, as bursts of contractions appear at a regular frequency of one/minute has however been observed in healthy volunteers and is thus not specific of IBS (Figure 4). 60 The motility in the area of the ileo-caecal valve has also been studied in IBS patients.…”

The Effect of a Multi-strain Probiotic on the Symptoms and Small Intestinal Bacterial Overgrowth in Constipation-predominant Irritable Bowel Syndrome: A Randomized, Simple-blind, Placebo-controlled Trial

“…Genetically determined lower resistance and unbalanced receptiveness to bacterial cell components, disorders of small intestinal peristaltics, and a dysfunctional the ileocecal valve could be grounds for changes of intestinal microbiome in IBS patients [8,22,25,28].…”