Fig. 3.

The effects of chronic buprenorphine on the priming strength of opioid partial agonists. The ability of buprenorphine (A), butorphanol (B), and nalbuphine (C) to reinstate drug-seeking behavior before and during chronic buprenorphine treatment (0.1 mg/kg per day). Left panels show the percentage injection lever responding, and right panels show the number of saline injections self-administered over a 30-minute session. Abscissae: dose (milligrams per kilogram) of opioid partial agonist administered as intramuscular priming injection. Ordinate: percentage injection lever responding (left), number of saline injections (right).