antinociceptive effect of the endemic species <i>glaucium vitellinum</i> boiss and buhse

Background]<i>glaucium vitellinum</i> is an endemic species and is extensively exploited as an antiinflammatory agent in iranian traditional medicine.[objectives]this study was designed to evaluate the antinociceptive activities of <i>g. vitellinum</i> methanol extract in male mice.[materials and methods]the formalin and hotplate methods were used for pain evaluation in mice. <i>glaucium vitellinum</i> extract (50, 100, 200 and 400 mg/kg body weight ip), saline and morphine (2 mg/kg, ip) were administered 15 minutes prior to the formalin test. the nociceptive responses were divided to two phases; phase І (0 15 minutes) and phase ІІ (15 60 minutes) were compared to the control and morphine. in the hotplate test, <i>g. vitellinum</i> extract (80, 160, 200 and 250 mg/kg ip), saline and morphine (5 mg/kg, ip) were administered and, behavioral responses were immediately tested, 15, 30, 45 and 60 minutes after the injection. comparisons between the groups were carried out using the analysis of variance (anova), and post hoc tukey’s test.[results]all doses of <i>g. vitellinum</i> extract induced antinociception activity during the first and second phases of the formalin test. the extract showed a significant (p lt; 0.05) doserelated inhibition during the first phase compared to the control group. in the second phase of the formalin test, the extract showed analgesic activity comparable to the effect of morphine. in pretreatment with nonselective opioid receptor antagonist, naloxone could reverse the antinociceptive effect of the extract in the formalin test. in the hotplate method, with the highest dose of 250 mg/kg, the antinociceptive activity of the studied extract was comparable to the standard drug, morphine.[conclusions]this study revealed that <i>g. vitellinum</i> extract possessed a significant antinociceptive activity in formalin pain models and hotplate test in mice and might have a potent role against pain.