- •The periaqueductal gray (PAG) contributes to morphine and oxycodone antinociception.
- •PAG microinjection of methadone or buprenorphine does not produce antinociception.
- •These mu-opioid receptor agonists produce antinociception via distinct mechanisms.
- •This functionally selective antinociception contributes to opioid variability.
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N.J.L. and T.M.S. are employees of Purdue Pharma, who provided funding and buprenorphine for this study.
The authors have no conflicts of interest to declare.