The behavioral effects of the nonpeptidic delta opioid agonist SNC80 were evaluated in rhesus monkeys. SNC80 (0.1–10 mg/kg as intramuscular injection) produced weak but replicable antinociceptive effects that were antagonized by naltrindole (1.0 mg/kg).

cAMP formation was measured with the protein binding assay. Cultures of recombinant or wildtype CHO cells. were transferred from the incubator to a 370C water-bath. After a 1-min incubation, the cells were rinsed once with IMDM (1.0 ml), covered with fresh IMDM (0.4 ml) containing 5.0 mM IBMX to prevent cAMP degradation and incubated for 1 min in a 37OC water bath. The stock solutions of drugs were prepared in water. Then the stock solutions of drug were added to IMDM containing water-soluble forskolin (Calbiochem Corp., San Diego, CA) to an appropriate final concentration. Basal cAMP formation was measured in cell cultures where drugs and forskolin were not added (IMDM alone). Forskolin-stimulated cAMP formation in the absence of agonist was defined as 100%. Agonist concentration-response curves were measured for SNC-80 (0.1 nM to 10 mkM).