- BACKGROUND & AIMS: Studies in inflammatory bowel disease have shown extensive structural abnormalities in the enteric nervous system of inflamed and noninflamed gut; however, functional correlates are lacking. The aim of this study was to determine the effect of colitis on myenteric nerve function at inflamed and noninflamed sites in rat intestine. METHODS: Tritiated noradrenaline release was measured from longitudinal muscle myenteric plexus preparations from the distal and transverse colon and terminal ileum of rats with colitis induced by trinitrobenzene sulfonic acid or Trichinella spiralis larvae. RESULTS: As characterized by myeloperoxidase activity and histology, both models induced inflammation restricted to the distal colon. In distal colon in trinitrobenzene sulfonic acid colitis, KCl- or electrical field stimulation-evoked 3H release was suppressed by 56% and 60%, respectively; in T. spiralis-infected rats, the KCl-evoked release was suppressed by 58%. 3H release was also suppressed by similar magnitudes in noninflamed transverse colon and terminal ileum of each model. CONCLUSIONS: Experimental distal colitis alters myenteric nerve function in inflamed distal colon and noninflamed gut regions. These changes are independent of the manner in which colitis is induced and provide a basis for the extensive disruption of physiological function observed in inflammatory bowel disease.