Dexamethasone modifies morphine-, atropine-, verapamil-induced constipation in mice

1. The effect of dexamethasone in gastrointestinal constipation induced by morphine, verapamil and atropine in mice has been studied. 2. These drugs caused a dose-related inhibition of charcoal meal transit, which was reversed by dexamethasone. 3. Dexamethasone resulted more active in reversing morphine and atropine constipation, than in modifying verapamil effect. 4. The authors concluded that the interaction of dexamethasone on its receptor could release a larger amount of acetylcholine resulting in a reversion of atropine- or morphine-induced constipation. 5. The minor effect of dexamethasone on verapamil-induced constipation suggest a reduced involvement of calcium influx. 6. The above results suggest a role for steroid in gastrointestinal transit and propose a possible mechanism through which dexamethasone could reverse morphine- and atropine-induced constipation.