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. 2017 Nov 17;13:1744806917743479. doi: 10.1177/1744806917743479

Figure 4.

Figure 4.

Naloxone blocks both free morphine and PolyMorphine-induced analgesia. (a) Mice treated with 10 mg/kg of free morphine and 10 mg/kg of naloxone (n = 6) show equal amounts of pain-like behaviors compared to control mice (n = 12). Mice treated with only 10 mg/kg of morphine (n = 5) show significantly less pain-like behaviors compared to the control and morphine/naloxone (10 mg/kg) groups. Naloxone (1 mg/kg, n = 6) was not a sufficient dose to block the analgesic effects of morphine. (b) SNI mice treated with 200 mg/kg of PolyMorphine and 10 mg/kg of naloxone (n = 6) prior to each post-injection time point remained hypersensitive compared to SNI mice (n = 6) that received PolyMorphine with vehicle injections. Formalin test—one-way ANOVA, overall main effect, ***P = 0.0007; Bonferroni post hoc tests, *P < 0.05 and ***P < 0.0001. von Frey test—two-way ANOVA, overall main effect of treatment, *P = 0.0211; overall main effect of time, ***P < 0.0001; Bonferroni post hoc tests, *P < 0.05 and ***P < 0.0001. SNI: spared nerve injury.