An exaggerated sensory component of the gastrocolonic response in patients with irritable bowel syndrome.
OBJECTIVE
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.


METHODS
We studied 13 healthy subjects and 16 patients with IBS-eight had diarrhoea predominant (IBS-D) and eight constipation predominant (IBS-C) IBS.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Postprandial symptoms in IBS patients may be explained in part by a nutrient dependent exaggerated sensory component of the gastrocolonic response.
Simrén
M
M
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden. magnus.simren@medicine.gu.se
Abrahamsson
H
H
Björnsson
E S
ES
D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D002404:Catheterization; D002766:Cholecystokinin / Q000097:blood; D003106:Colon / Q000503:physiopathology*; D003109:Colonic Diseases, Functional / Q000097:blood / Q000503:physiopathology* / Q000523:psychology*; D003248:Constipation / Q000097:blood / Q000503:physiopathology / Q000523:psychology; D003967:Diarrhea / Q000097:blood / Q000503:physiopathology / Q000523:psychology; D004041:Dietary Fats / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009037:Motilin / Q000097:blood; D009478:Neuropeptide Y / Q000097:blood; D017288:Pain Threshold; D010191:Pancreatic Polypeptide / Q000097:blood; D019894:Peptide YY / Q000097:blood; D019518:Postprandial Period; D011312:Pressure; D018709:Statistics, Nonparametric; D013270:Stomach / Q000503:physiopathology*; D014660:Vasoactive Intestinal Peptide / Q000097:blood
D004041:Dietary Fats; D009478:Neuropeptide Y; D019894:Peptide YY; D014660:Vasoactive Intestinal Peptide; D009037:Motilin; D010191:Pancreatic Polypeptide; D002766:Cholecystokinin