Sensitization of stereotyped behavior to amphetamine is context and response dependent

The present study was designed to determine whether the environmental conte xt in which amphetamine is administered plays a role in the development of sensitization to the stereotyped behavioral effects of amphetamine in mice. In male CF-1 mice, the dose-response curve for stereotyped behavior elicit ed by amphetamine was shifted 1.9-fold to the left 48 h after pretreatment with 14 mg/kg amphetamine. Behavioral sensitization only developed in mice that were pretreated in the same or a similar environment as that of the te st environment. In addition, when mice were placed in an environment that a ttenuated the acute expression of stereotyped behavior elicited by the pret reatment dose of amphetamine, sensitization never developed. A further expe riment showed that 96% of the mice that expressed stereotypy after the ED50 pretreatment dose of 10 mg/kg amphetamine showed a stereotyped behavioral response to the lesser dose of 7 mg/kg 48 h later, indicating sensitization . In contrast, mice that did not express stereotypy after the ED,, dose of amphetamine failed to show a significant stereotyped behavioral response to amphetamine challenge compared to vehicle-pretreated controls. Therefore, the results indicate that preexposure to a single high dose of amphetamine produces context- and response-dependent sensitization to amphetamine-induc ed stereotyped behavior. (C) 1999 Elsevier Science Inc.