Figure 5.

Effect of naloxone on antinociception spinal p-CREB expression induced by chrysin in the formalin test. After i.p. pretreatment with naloxone (5 mg/kg) for 10 min, mice were administered orally with chrysin (100 mg/kg) for 30 min prior to the formalin (5%, 10 μl) injection subcutaneously into the plantar aspect of the left side hind-paw. The proteins were extracted from dissected lumbar spinal cord 30 min after formalin injection for Western blot analysis. The number of animals in each group is 6. β-Actin (1:1000 dilution) was used as an internal loading control. The vertical bars indicate the standard error of the mean. (**p < 0.05, compared with formalin group; ⁺⁺p < 0.05, compared with formalin+chrysin group).