Fig. 5. Enduring effects of male juvenile exposure to concomitant ketamine (KET)-and-stress [social defeat stress (SDS), vicarious defeats stress (VDS), or no-stress control (CON)] on cocaine and sucrose preference in adulthood.

a Neither KET or stress combination treatment (n = 8–10 per group) influenced preference scores for the compartment conditioned to saline (i.e., 0 mg/kg cocaine; p > 0.05). In contrast, all experimental male mice displayed reliable conditioning to 5 and 10 mg/kg cocaine, when compared to respective groups conditioned to saline (cocaine main effect, p < 0.05). Furthermore, adult mice pre-exposed to saline-vehicle (VEH) and VDS during adolescence, showed an enhanced preference to 5 and 10 mg/kg cocaine, when compared to VEH+CON mice receiving the same doses (*p < 0.05, respectively). Similarly, adult mice pre-exposed to KET+CON showed a higher preference score to 5 and 10 (*p ≤ 0.05) mg/kg cocaine, when compared to VEH+CON mice receiving the same doses of cocaine. b KET-pretreatment, independent of stress history, resulted in lower distance traveled during the preconditioning phase (main effect of stress, ^βp < 0.05). c Adolescent stress history (VDS or SDS), independent of KET or VEH pretreatment, resulted in decreased preference for a 1% sucrose solution in adulthood (main effect of stress; ^χp < 0.05). d KET-pretreatment, independent of stress history, resulted in decreased liquid intake in adulthood (main effect of KET-pretreatment, ^βp < 0.05).