Caffeine-diazepam interaction and local cerebral glucose utilization in the conscious rat

The quantitative 2-[14C]deoxyglucose autoradiographic method was used to study the effects of the acute administration of a sedative anticonvulsant dose of diazepam (2 mg/kg) on rat brain energy metabolism. This benzodiazepine was injected to rats chronically treated for two weeks either by caffeine (10 mg/kg/day) or by saline. After the administration of diazepam to saline-treated rats, average glucose utilization of the brain as a whole was reduced by 21% and rates of glucose utilization were deeply decreased in frontal and auditory cortex, mammillary body, lateral thalamus, medial and lateral geniculate. In caffeine-treated rats, the administration of diazepam induced the same effects of brain energy metabolism as in saline-treated rats. The results of the present study indicate that diazepam mainly decreases glucose utilization in structures widely believed to mediate anxiety.