Figure 2
Human immunodeficiency virus 1 (HIV-1) Tat induction potentiated cocaine-conditioned place preference (CPP). (a). Post-conditioning preference was potentiated in Tat-induced mice. C57BL/6J mice (white bars left of dashed line) pretreated with Dox (100 mg/kg, striped white bar) demonstrated a cocaine-CPP that was similar to vehicle-pretreated C57BL/6J mice (0.9% saline, solid white bar), demonstrating that there was no effect of Dox pretreatment itself on CPP. Post-conditioning responses of the C57BL/6J and uninduced GT-tg mice (solid gray bar right of dashed line) did not differ significantly from each other. In contrast, Tat-induced GT-tg mice (striped gray bar) showed a significantly increased cocaine-CPP compared with C57BL/6J and uninduced mice. (*Indicates significant difference from all other post-CPP responses, p<0.05, two-way analysis of variance (ANOVA). (b) Tat-induced potentiation of cocaine-CPP was Dox dose-dependent. GT-tg bigenic mice induced with 25 mg/kg Dox for 7 days (striped white bar) did not demonstrate a significantly potentiated cocaine-CPP compared with vehicle-pretreated (ie, uninduced, solid white bar) GT-tg bigenic mice. GT-tg mice administered 50 mg/kg Dox for 7 days (striped gray bar) showed an elevated cocaine-CPP, which did not differ from uninduced mice, but also did not differ from mice induced with the maximum Dox dose (100 mg/kg, 7 days, striped dark gray bar). (*Indicates significant difference from uninduced GT-tg bigenic mice, p<0.05, one-way ANOVA.). (c) Potentiation of cocaine-CPP was dependent on the length of induction of Tat. GT-tg bigenic mice induced with 100 mg/kg Dox for 1 or 3 days (first and second striped light gray bars, respectively) did not demonstrate a significant difference in cocaine-CPP as compared with uninduced GT-tg bigenic mice (solid white bar). However, mice administered 100 mg/kg Dox for 5 and 7 days (third and fourth striped gray bars, respectively) showed a significant potentiation of cocaine-CPP compared with uninduced mice. *Indicates significant difference from uninduced GT-tg bigenic mice, p<0.05, one-way analysis of variance (ANOVA.)
