Figure 4

Role of the peripheral nitric oxide-cGMP-PKG-KATP signaling pathway in the antiallodynic effects of morphine. Mechanical (A, C, E) and thermal (B, D, F) antiallodynic effects of the subplantar co-administration of morphine (400 nmol) plus vehicle or different doses of ODQ (4.0 - 13.3 nmol; A, B), Rp-8 (1.2 - 4.1 nmol; C, D) or glibenclamide (Glib; 20.2 - 60.7 nmol; E,F) in the ipsilateral paw of sciatic nerve-injured WT mice at 21 days after surgery. The effects of the subplantar administration of vehicle and the maximal doses of ODQ (13.3 nmol), Rp-8 (4.1 nmol) or glibenclamide (60.7 nmol) injected alone are also shown. All drugs were administered 20 min before starting behavioral testing. Data are expressed as mean values of the maximal possible effect (%) for mechanical allodynia and as inhibition (%) for thermal allodynia ± SEM (5-6 animals per group). For each behavioral test and selective inhibitor assayed, * P < 0.05 denotes significant differences vs. group treated with morphine plus vehicle (one way ANOVA followed by the Student Newman Keuls test) and + P < 0.05 denotes significant differences vs. group treated with vehicle (one way ANOVA followed by Student Newman Keuls test).