COLONIC AND JEJUNAL MOTOR DISTURBANCES AFTER COLONIC ANTIGEN CHALLENGE OF SENSITIZED RAT

Background & Aims: Inflammation in the colon may alter motility in the proximal gut and potentiate clinical symptoms, The aim of this study was to characterize the effect of colonic anaphylaxis on local (coloni c) and remote (small intestinal) motility and identify the mechanism a nd mediators involved. Methods: Rats were sensitized by intraperitonea l injection of 10 mu g egg albumin and surgically prepared with electr odes in jejunum and colon and a colostomy tube. Colonic and jejunal my oelectric activity were recorded in fasted animals before and after co lonic antigen challenge without and then after pretreatment with speci fic antagonists, Results: Colonic antigen challenge of sensitized rats was associated with significant (1) increase in colonic myoelectric s pike activity, (2) disruption of fasting jejunal motility and initiati on of aborally propagating spike complexes, and (3) increase in plasma rat mast cell protease II levels with a decrease in granulated mast c ells in colon but not jejunum, The myoelectric disturbance in both col on and jejunum was inhibited significantly by pretreatment with atropi ne and hexamethonium, doxantrazole, cyclooxygenase, and lipoxygenase i nhibitors. Methysergide inhibited only the jejunal disturbance, Conclu sions: Colonic antigen challenge of sensitized animals results in loca l mast cell activation and the release of mediators that modulate neur al pathways to initiate both a local colonic and a remote jejunal myoe lectric disturbance.