Figure 7.

Antinociceptive effects of corydine (1), corydaline (2), and the reference MOR ligand morphine in the acetic acid-induced writhing assay in mice after s.c. administration. Mice received s.c. vehicle (control), test compounds, or morphine, and the number of writhes were counted at 30 min after administration of compounds 1 (5 mg/kg) and 2 (10 mg/kg), or morphine (0.5 mg/kg) administration, for a period of 10 min. Naltrexone (NLX, 1 mg/kg) was s.c. administered 10 min before compounds 1 or 2. Values are means ± SEM (n = 5–6 mice per group). **P < 0.01 and ***P < 0.001 vs. control group; ^##P < 0.01 vs. agonist-treated group; one-way ANOVA followed by Tukey’s post hoc test or unpaired t-test.