Effect of alpha-helical CRH on quantitative electroencephalogram in patients with irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) may have a higher tone of corticotropin-releasing hormone (CRH) in the brain. We tested our hypothesis that peripheral administration of CRH antagonist, α-helical CRH _9-41 (αhCRH), improves decreased alpha power spectra and increased beta power spectra of electroencephalogram (EEG) in IBS patients. A barostat bag was inserted to the descending colon of 10 normal controls and 10 IBS patients. The EEG power spectra and topography were measured during baseline period and colonic distention period with the administration of saline followed by the administration of 10 μg kg^-1 of αhCRH. IBS patients showed a significantly lower alpha power percentage and a higher beta power percentage than normal controls during baseline. Colonic distention induced a decrease in the alpha power percentage and an increase in the beta power percentage in both groups without difference between groups. After the administration of αhCRH, changes in the EEG power spectra in response to colonic distention were blunted and the differences in the EEG power spectra between IBS patients and controls vanished. Peripheral administration of αhCRH almost normalized EEG activities in IBS patients. Our data strongly suggest that CRH plays an important role in IBS.