Effect of SB334867 on conditioned reinstatement induced by discriminative stimuli associated with oxycodone. A. Oxycodone self-administration. ***p < 0.001, vs. inactive lever; ###p < 0.001, vs. day 1 (Sidak post hoc test). B. Somatic withdrawal signs. #p < 0.05, ##p < 0.01, ###p < 0.001, vs. day 2 (Dunn’s post hoc test). Inset. Correlation plot between the somatic withdrawal score and number of oxycodone infusions. C. Extinction training over 14 sessions (2 h/day). *p < 0.05, ***p < 0.001, vs. inactive lever; #p < 0.05, ##p < 0.01, ###p < 0.001, vs. day 14 (Sidak post hoc test). D. Discriminative stimuli (Sd) that were conditioned to oxycodone induced response-reinstating behavior following the vehicle injection. SB334867 (5, 10, and 30 mg/kg) reduced Sd-induced oxycodone-seeking behavior. **p < 0.01, vs. inactive lever; ###p < 0.001, vs. EXT and Sn; +p < 0.05, +++p < 0.001, vs. vehicle (Sidak post hoc test). n = 7.