RESUMO
There are some reports in Iranian traditional medicine concerning the anti-inflammatory effect of Saliva Officinalis [SO]. In the present study with the aim of decreasing analgesic dose of morphine, analgesic effect of different doses of SO hydroalcoholic extract alone and associated with morphine were evaluated by tail flick in rats. Analgesic effects of SO hydroalcholic extract at doses of 200, 400, 600, 800 and 1000 mg/kg, i.p. were investigated. Then the influence of these doses associated with analgesic dose of morphine [2.5 mg/kg] was evaluated. Rats were placed into restrainer and then transferred into the tail flick apparatus with the intensity 55§C and cut off time=10 sec. In order to verify the role of opioid receptors on analgesic effect of SO extract, naloxone [1mg/kg, i.p.] was administered to one group of rats 15 min before receiving 800 mg/kg extract. Then, the data were analyzed by two-way ANOVA followed by LSD post hoc test and significant difference between groups was accepted with P<0.05. The Data have shown that, the SO extract relieved pain in tail-flick test dose dependently and the most effective dose was 800 mg/kg. The maximum analgesic effect of the extract combined with morphine was observed at time point 45 min. Naloxane, opioid receptor antagonist could reduce analgesic effect of the extract. On the basis the results obtained in this study, it could be suggested that the SO extract potentiates morphine antinociceptive effect and this means that the opioid system may be involved in the analgesic effect of this plant extract