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. Author manuscript; available in PMC: 2020 Jun 1.
Published in final edited form as: Neuropharmacology. 2019 Feb 15;151:208–218. doi: 10.1016/j.neuropharm.2019.02.019

Fig. 1. Dose response curves for the KOP agonist, U50488, the DOP agonist, DPDPE, and the DOP-KOP heteromer agonist, 6’-GNTI, for reduction in PGE2-evoked thermal allodynia in the rat hindpaw.

Fig. 1.

Animals received intraplantar (i.pl.) injections of BK (25 μg) 15 min before co-injection of PGE2 (0.3 μg) and vehicle or the indicated doses of U50488 (A), DPDPE (B) or 6’-GNTI (C). The MEK inhibitor, U0126 (10 μg) was administered along with BK 15 min prior to co-injection of PGE2 and opioid agonist. PWL was measured in duplicate before injections and at 5 min intervals for 20 min after the last injection. Data shown are expressed as the change (in sec) in PWL from pre-injection baseline at the 10 min timepoint following the last injection. Each data point represents mean ± SEM of 6 animals per group. Baseline PWL averaged 9.66 s ± 0.21. Inhibition of ERK activation with U0126 significantly altered the U50488 dose-response curve (F(1,81) = 6.215, P = 0.0147). *P < 0.05, **P < 0.01 compared to Vehicle, two-way ANOVA (dose and treatment as factors) with Bonferroni’s post test. Full timecourse data are shown in Supplemental Fig. 1–3.