DIFFERENTIAL DEVELOPMENT OF THE ENHANCED METABOLIC RESPONSE DURING AMPHETAMINE SENSITIZATION

Behavioral sensitization elicited by repeated administration of amphet amine does not fully develop until a period after discontinuation of a mphetamine, but then persists undiminished for a long time. This exper iment investigated the regional metabolic changes in rats pretreated w ith amphetamine and challenged after different abstinence periods (2, 7 and 28 days), using the 2[C-14]deoxyglucose method. The results demo nstrated that chronic amphetamine administration enhanced rates of loc al cerebral glucose utilization in specific cerebral regions. The magn itude and distribution of effects varied with the abstinence period. A challenge dose of d-amphetamine 2 days after pretreatment was found t o have no more, or only mildly elevated, local cerebral glucose utiliz ation compared with that following a single acute dose. In rats challe nged at the 7th and 28th day, a supersensitive metabolic response was found in dopaminergic and non-dopaminergic areas. This finding suggest ed regional differences in the development of sensitization and unders cored the importance of an abstinence period in the study of sensitiza tion and amphetamine psychosis.