Cocaine and amphetamine modification of cerebral energy metabolism in vivo

At the time of maximal behavioral stimulation after injection of amphetamine (5 mg/kg) in mice, elevation of cerebral cortical levels of malate in the citric acid cycle and of the amino acid, alanine, was observed, suggesting that this drug has widespread effects on energy metabolism. Cocaine (20 mg/kg), in contrast, produced elevation of brain glucose but not of citric acid cycle substrates or amino acids at the time of maximal hyperactivity. These observations are discussed in terms of the mechanisms of action of these two central nervous system stimulants.