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. Author manuscript; available in PMC: 2017 Sep 1.
Published in final edited form as: Drug Alcohol Depend. 2016 Jun 25;166:51–60. doi: 10.1016/j.drugalcdep.2016.06.020

Figure 1.

Figure 1

Schematic of the experimental paradigm. Each session following training assessed breakpoints on a progressive-ratio schedule of reinforcement using cocaine (0.1875, 0.375, 0.75 mg/kg/infusion) across three phases based on treatment. Phase 1 (blue shaded) tested the effects of LY379268 (0.03 or 0.30 mg/kg, counterbalanced) alone, Phase 2 (non-shaded/white) allowed time for breakpoints to stabilize after the last LY379268 dose, Phase 2 (green and white checker shaded) tested the effects of phenmetrazine alone, and Phase 3 (green shaded) tested the combined effects of LY379268 and phenmetrazine on cocaine breakpoints. Osmotic mini-pump delivered phenmetrazine (25 mg/kg/day). FR1, fixed ratio 1; PR, progressive ratio.