Corticotropin-releasing hormone-induced changes in colonic tone in patients with irritable bowel syndrome

Background: Corticotropin-releasing hormone (CRH) signaling pathway in the gut may contribute to stress-related progression and exacerbation of irritable bowel syndrome (IBS) symptoms. We tested the hypotheses that IBS patients show exaggeration of phasic and tonic motility responses in the colorectum after exogenous CRH.
Methods: Twenty-one IBS patients and 19 healthy controls (HC) participated. Colonic motility was recorded for 20 min as a baseline period and for 120 min after intravenously administration of CRH (2 μ/kg) using a barostat. Average bag volumes and phasic volume events (PVEs) during the baseline and for 120 min after CRH injection were measured. An ordinate scale was used to assess IBS symptoms before and after administration of CRH.
Results: There was no significant difference in the bag volume or number of PVEs during the baseline between IBS and HC. After administration of CRH, IBS patients showed less bag volume (p<0.01) and more phasic contractions (p=0.05) at 60-120 min period compared to HC. No significant differences in symptom scores were found between IBS and HC groups after administration of CRH.
Conclusions: IBS patients are likely to show more increased tone and fine contractions in the colorectum at events with peripheral CRH administration. These findings support the idea that more increased peripheral CRH signaling pathway may induce exaggeration of gastrointestinal motility responses as well as abnormal central CRH system in IBS patients.