Reinforcing effects of opioidcannabinoid mixtures in rhesus monkeys responding under a fooddrug choice procedure.
Cannabinoid receptor agonists such as delta-9-tetrahydrocannabinol (Δ In this study, rhesus monkeys (n 4) responded under a choice procedure wherein responding on one lever delivered sucrose pellets and responding on the other lever delivered intravenous infusions of the mu opioid receptor agonist remifentanil (0.032-1.0 μgkginfusion) alone or in combination with either Δ Remifentanil dose-dependently increased choice of drug over food, whether available alone or in combination with a cannabinoid, and the potency of remifentanil was not significantly altered by coadministration with a cannabinoid. Mixtures containing the largest doses of cannabinoids decreased response rates in most subjects, confirming that behaviorally active doses were studied. Overall, these results extend previous studies to include choice behavior and show that cannabinoids do not substantially enhance the reinforcing effects of mu opioid receptor agonists.