Figure 7. Cocaine self-administration enhances D₂ DA receptor sensitivity in both LD₂ and HD₂ rats.

(A) Quinpirole AUC scores were enhanced across the entire cohort of animals tested following cocaine self-administration. *After cocaine significant from Before cocaine, p<0.05 (B) Likewise, this enhancement was observed across all quinpirole doses. *After cocaine significant from Before cocaine, p<0.05. (C and D) Cocaine-induced enhancements in D₂ DA receptor sensitivity were apparent in both the LD₂ and HD₂ groups using both the quinpirole AUC scores and raw locomotor scores across the quinpirole dose response curve. *After cocaine significant from Before cocaine, p<0.05. Interestingly, the group differences persisted even after cocaine exposure. † HD₂ significant from LD₂, p<0.05.