Fig. 4.

The effects of chronic buprenorphine on the antinociceptive and behaviorally disruptive effects of opioid full agonists. The ability of methadone, heroin, and oxycodone to produce increases in tail withdrawal latency (top panels) or decreases in food-maintained behavior (bottom panels) before and during chronic buprenorphine treatment (0.1 and 0.32 mg/kg per day). Abscissae: dose (milligrams per kilogram) of opioid full agonist administered using cumulative dosing. Ordinates: latency to withdraw tail from 55°C water (seconds) (top panels) and response rate (responses/second) (bottom panels).