<i>IN VIVO</i> EFFECTS OF AMPHETAMINE ON METABOLITES AND METABOLIC RATE IN BRAIN

Abstract

Abstract —The concentrations of several metabolites, including glucose, glycogen, glucose‐6‐phosphate, lactate, ATP and phosphocreatine have been measured in the brains of mice rapidly frozen at various intervals after the intraperitoneal injection of d ‐amphetamine sulphate (5 mg/kg). During the initial 30 min following injection, amphetamine induced a fall in cerebral glycogen and phosphocreatine and an elevation of lactate. Changes in glucose and brain/blood glucose ratios were less marked over this period. The metabolite levels returned to control values at 60 min. The cerebral metabolic rate calculated by the ‘closed system’ technique also showed a biphasic change. An initial depression of energy flux over the first 15 min following amphetamine injection was followed by an increase that appeared to be closely associated with the increase in locomotor activity over this period. The results have been discussed in relation to the known catecholamine‐releasing action of amphetamine, and differential effects on glial cells and neurons have been proposed.