THE INFLUENCE OF MORPHINE ON MAGNESIUM METABOLISM IN RATS

¹ Department of Pharmacology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada

Administration of morphine sulfate, 2 mg/kg, caused an increase in serum magnesium in rats. A dose-response curve was obtained up to 16 mg/kg. The hypermagnesemia reached a peak one hour after injection of the narcotic. It then slowly decreased, to return to normal values six hours after morphine administration. Nalorphine hydrochloride, which was slightly effective per se, antagonized the hypermagnesemia when administered simultaneously with the agonist. After i.v. administration of Mg²³, there was an increase in the specific activity of serum, bone and muscle in morphine-treated rats. These observations are taken as evidence that morphine has an effect on magnesium metabolism in rats.