THE INFLUENCE OF MORPHINE ON GLUCOSE UTILIZATION IN CEREBRAL PREPARATIONS OF RATS

¹ Department of Pharmacology, State University of New York, Upstate Medical Center, Syracuse, New York

The aerobic and anaerobic glucose uptake of cerebral cortical slices taken from morphinized rats are greater than those of slices taken from control rats. The glucose uptake of slices also increases when morphine is added in vitro. The increased glucose utilization is seen with cerebral homogenates at much lower concentrations of morphine in vitro than that used with cerebral slices. Oxygen uptake and lactate formation do not account for the increased glucose uptake by the cerebral slices. Other central nervous system depressants such as pentobarbital and ethanol do not increase aerobic glucose uptake of the cerebral slices.

The increase in cerebral glucose uptake due to morphine in vitro is most apparent when the uptake is being depressed by KCl anaerobically. The depressed anaerobic glucose uptake and lactate formation in the presence of KCl are also increased by additions of ethanol or pentobarbital in vitro. The increase in lactate formation accounts for the increase in glucose uptake under the influence of either ethanol or pentobarbital. However, in the presence of morphine, lactate formation does not account for the greater increase in glucose uptake.