vasoactive-intestinal-peptide and Colonic-Diseases--Functional

In irritable bowel syndrome (IBS), motility disturbances occur from the upper gastrointestinal tract to the distal colon, where regulatory peptides have a wide-spread distribution. Studies on basal and postprandial plasma levels of different gut hormones show that VIP, CCK, and motilin may be closely related to the symptoms including abdominal pain, diarrhea and constipation. In addition, peptide YY and NPY have effects on absorption in the intestine, and some opioid peptides exert actions on colonic motility in IBS patients. Recent studies revealed that gall bladder in IBS has an abnormal sensitivity to CCK-8, indicating that IBS patients has an generalized abnormality of the smooth muscle of the digestive tract. Gut hormones, which act as hormones, neurotransmitters and neuromodulators depending on their releasing site, may therefore play an important role in IBS patients.

Topics: Animals; Cholecystokinin; Colonic Diseases, Functional; Gastrointestinal Motility; Humans; Motilin; Neuropeptide Y; Peptide YY; Peptides; Rats; Rats, Sprague-Dawley; Vasoactive Intestinal Peptide

Visceral hypersensitivity is a feature of the irritable bowel syndrome (IBS). Postprandial symptoms are common in these patients. The effects of nutrients on colonic perception in IBS are incompletely understood.. We studied 13 healthy subjects and 16 patients with IBS-eight had diarrhoea predominant (IBS-D) and eight constipation predominant (IBS-C) IBS.. Colonic perception thresholds to balloon distension and viscerosomatic referral pattern were assessed before and after duodenal infusion of lipid or saline, respectively. At the end of the infusions, plasma levels of gastrointestinal peptides were determined.. Lipids lowered the thresholds for first sensation, gas, discomfort, and pain in the IBS group but only for gas in the control group. The percent reduction in thresholds for gas and pain after lipids was greater in the IBS and IBS-D groups but not in the IBS-C group compared with controls. IBS patients had an increased area of referred discomfort and pain after lipids compared with before infusion whereas the referral area remained unchanged in controls. No group differences in colonic tone or compliance were observed. In both groups higher levels of cholecystokinin, pancreatic polypeptide, peptide YY, vasoactive intestinal polypeptide, and neuropeptide Y were seen after lipids. Motilin levels were higher in patients and differences in the subgroups were observed. Levels of corticotrophin releasing factor were lower in the constipated group than in the diarrhoea group.. Postprandial symptoms in IBS patients may be explained in part by a nutrient dependent exaggerated sensory component of the gastrocolonic response.

Topics: Adult; Analysis of Variance; Case-Control Studies; Catheterization; Cholecystokinin; Colon; Colonic Diseases, Functional; Constipation; Diarrhea; Dietary Fats; Female; Humans; Male; Middle Aged; Motilin; Neuropeptide Y; Pain Threshold; Pancreatic Polypeptide; Peptide YY; Postprandial Period; Pressure; Statistics, Nonparametric; Stomach; Vasoactive Intestinal Peptide

To assess the levels of gut peptides involved in gastrointestinal motor, secretory and sensory function in colonic biopsies in irritable bowel syndrome (IBS) patients and healthy controls.. We studied 34 patients with IBS and 15 subjects without gastrointestinal symptoms. The predominant bowel pattern in the IBS patients was constipation in 17 patients (IBS-C) and diarrhoea in 17 patients (IBS-D). With radioimmunoassay, the levels of vasoactive intestinal peptide (VIP), substance P, neuropeptide Y (NPY) and peptide YY (PYY) were analysed in biopsies from the descending colon and ascending colon obtained during colonoscopy.. The IBS patients had lower levels of PYY in the descending colon than the controls, but the levels in the ascending colon did not differ. The NPY levels were lower in IBS-D than in IBS-C, both in the ascending colon and in the descending colon. Low levels of VIP were more common in IBS patients, but mean levels did not differ between groups. No group differences were observed for substance P. The levels of VIP, substance P and NPY were higher in the ascending colon than in the descending colon, whereas the opposite pattern was seen for PYY.. IBS patients demonstrate lower levels of PYY in the descending colon than controls. Colonic NPY levels differ between IBS subgroups based on the predominant bowel pattern. These findings may reflect the pathophysiology of IBS and the symptom variation within the IBS population.

Topics: Adult; Aged; Biopsy; Case-Control Studies; Colon; Colonic Diseases, Functional; Constipation; Diarrhea; Female; Humans; Male; Middle Aged; Neuropeptide Y; Peptide YY; Substance P; Vasoactive Intestinal Peptide

A highly sensitive radioimmunoassay system for plasma vasoactive intestinal peptide (VIP) was developed to examine the effect of intraduodenal infusion of HCl or fat on the plasma VIP levels in healthy subjects, and the effect of intramuscular injection of neostigmine in patients with irritable bowel syndrome (IBS). Intraduodenal infusion of 100 ml of 0.1 N HCl or 10 g fat caused a significant rise in plasma VIP level. Neostigmine (12.5 micrograms/kg) produced a significant rise in plasma VIP level, and the plasma VIP response to neostigmine was significantly greater in the IBS group than in the normal group. These results suggest that VIP might play a role in the pathophysiology of IBS.

Topics: Adult; Aged; Colonic Diseases, Functional; Duodenum; Fat Emulsions, Intravenous; Female; Humans; Hydrochloric Acid; Injections, Intramuscular; Male; Middle Aged; Neostigmine; Radioimmunoassay; Vasoactive Intestinal Peptide