Figure 4.

Effect of naloxone, yohimbine or methysergide on antinociception induced by chrysin in the formalin test. After i.p. pretreatment with naltrexone, yohimbine or methysergide (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 number of animals in each group is 6. The vertical bars indicate the standard error of the mean. (**p < 0.01, compared with formalin-treated group; ⁺⁺p < 0.01, compared with formalin+chrysin group).