Naloxone fails to alter local cerebral glucose utilization in the rat.

The autoradiographic, 2-deoxy-D-[1-14C]glucose ([14C]DG) method was used to map the effects of intravenous (IV) naloxone (1.0, 10.0, and 20.0 mg/kg) on local cerebral glucose utilization (LCGU), an index of local brain function. Naloxone injected 5 min before [14C]DG did not alter LCGU in any of the fifty-six brain regions examined. Our findings suggest that acute naloxone at these doses does not significantly affect cerebral metabolism.