Background & Aims: Lipopolysaccharide-induced colonic dysmotility using an in vivo rat model was examined in this study. Methods: Six days prior to the experiment, force transducers were sutured to the proximal colons of the rats. On the day of the experiment, while monitoring colonic contractions, lipopolysaccharide (LPS)(1mg/kg) was given intravenously. Results: LPS injections induced abnormal high amplitude colonic contractions within 15 to 30 min in all the rats tested. After the period of these abnormal waves, motility gradually decreased. These high amplitude contractions were partly suppressed by atropine, a nonspecific cholinergic receptor antagonist. Conclusions: These results...