Fig. 4

Involvement of opioid/dynorphin system in the antinociceptive effect of PCW in CFA-induced mice. a Mice were intraplatar injected with CFA, 48 h later, mice were pretreated with cyprodime (2.3 μmol/kg, i.p.) or nor-binaltorphimine (nor-BNI, 13.6 μmol/kg, s.c.) or naltrindole (11.1 μmol/kg, i.p.). After 15 min, the mice received an administration of PCW (1.35 g/kg, p.o.) or distilled water (10 ml/kg, p.o.), and the mechanical hypersensitivity of right hind paw was evaluated 1 h later. Antinociceptive effects of PCW were also evaluated co-administration of nor-BNI (a, b) and anti-dynorphin A (1–13) antiserum (c, d) in mechanical and heat hypersensitivity tests, and this effect was also performed pretreated with nor-BNI in the hot plate test (e). Data are represented as the mean ± SEM. (n = 6). ^### P < 0.001 vs. the control group; *P < 0.05 and ***P < 0.001 vs. the CFA group, respectively