INHIBITION OF INTESTINAL MOTILITY AND REVERSAL OF POSTLAPAROTOMY ILEUS BY SELECTIVE ALPHA-2-ADRENERGIC DRUGS IN THE RAT

Background: The effects of selective α-agonist medetomidine and α2-antagonist atipamezole on gastrointestinal motility were studied. Methods: The passage of intragastrically administered Evans blue in the small bowel of unanesthetized rats was followed, and the stomachs were weighted after killing the rats. Results: Subcutaneous medetomidine, 0.01-0.1 mg/kg, was found to delay small intestinal transit but not gastric emptying, with a maximal effect seen at 0.03 mg/kg. Atipamezole fully reversed the effect of 0.1 mg/kg of medetomidine with a dose of 2.5 mg/kg. Atipamezole alone did not affect small intestinal transit. Subcutaneous morphine, 6 mg/kg, delayed gastric emptying and small intestinal transit, whereas intraperitoneal morphine only delayed gastric emptying. Subcutaneous atipamezole, 0.06 mg/kg, was partially able to reverse the delayed intestinal transit but did not inhibit morphine-induced gastric retention. Subcutaneous atipamezole, 0.06 mg/kg, reversed laparotomy-induced ileus completely. Conclusions: Atipamezole may provide a useful treatment for postlaparotomy ileus. © 1993.