Are gut peptides responsible for the irritable bowel syndrome (IBS)?

Disturbances in gut motor activity have been proposed as a characteristic phenomenon in patients with irritable bowel syndrome (IBS). The symptoms are often associated with food intake. Several neuropeptides have a stimulatory or inhibitory effect on intestinal smooth muscle contraction. Studies on basal and postprandial plasma levels of different neuropeptides have therefore been performed in patients with IBS and been compared with those of a control group. In the whole group of IBS patients no typical gut hormone profile was found in plasma. When the IBS patients were divided into subgroups based on the predominant syndrome changes in the plasma levels of gastrin, motilin and pancreatic polypeptide (PP) were seen. In diarrhoea fasting levels of motilin and PP and postprandial level of PP were increased. In constipated patients fasting levels of gastrin and motilin and postprandial levels of gastrin, motilin and PP were decreased. Fasting and postprandial levels of gastrin were also decreased in patients with predominantly abdominal pain.