[A] Total presses (mean ± SEM) on the active (black circles) or inactive lever (white circles; left X-axis), and total number of oxycodone infusions obtained (gray circles; right X-axis) are presented for the acquisition of oxycodone self-administration. [B] The effects and specificity of lorcaserin (0.25, 0.5, 1 mg/kg) to alter total oxycodone infusions (mean ± SEM) are presented. Lorcaserin (1.0 mg/kg) suppressed oxycodone intake relative to vehicle (*p < 0.05 vs. VEH; left panel) while pretreatment with SB 242084 (0.5 mg/kg; right panel) reversed the effects of lorcaserin (1.0 mg/kg) (ˆ p < 0.05 vs. 1 mg/kg of lorcaserin). [C] The effects of lorcaserin (0.25, 0.5, 1 mg/kg) or vehicle (VEH) on cumulative oxycodone infusions (mean ± SEM) are presented. Lorcaserin (1.0 mg/kg) suppressed oxycodone intake across all time bins (* p < 0.05 vs. VEH).