Effects of Repeated High-Dose Methamphetamine on Local Cerebral Glucose Utilization in Rats

Repeated administration of high doses of methamphetamine (MAP) to rats can induce long-lasting neurotoxicity which may be related to permanent psychotic symptoms and negative symptoms in some MAP psychotic patients. In this study, we used the 2-[14C]deoxyglucose (2DG) method to analyze the effects of repeated MAP administration (12.5 mg/kg, i.p., 4 times every 2 hr within a day) 14 days and 60 days after drug administration. The results showed a wide-spread (26 of the 43 regions examined) decreases in the regional cerebral glucose utilization. The regions with decrease metabolism included all the extrapyramidal systems, the hippocampus formation and dorsal raphe nucleus. Rats tested 60 days after drug administration has similar finding to those with a 14-day abstinent period. The results of the functional change in this study provide support for the neurotoxic effects of repeated high dose MAP administration in rats. Furthermore, the neurotoxic effects are selective and long-lasting. We suggested the MAP neurotoxic model can be used to study the permanent psychosis and negative symptoms of MAP-induced psychosis in humans.