Animals received an injection of 500 μg carrageenan (i.pl.) 15 min before injection (i.pl.) of vehicle or U50488 (0.1 μg), DPDPE (20 μg), or 6’-GNTI (1 μg). PWL was measured in duplicate before and every 5 min for 20 min after injection with agonist. Data are expressed as change (in sec) from individual PWL baselines at each timepoint and represent mean ± SEM of 20 (Veh), 18 (6’-GNTI), or 6 (DPDPE, U50488) animals per group; *P < 0.05; ***P < 0.001; ****P < 0.0001 vs. vehicle, two-way ANOVA with Bonferroni’s post test.