STUDY OF ANTINOCICEPTIVE EFFECTS OF ZIZIPHORA TENUIOR AND ITS INTERFERENCE ON OPIOIDERGIC AND SEROTONINERGIC SYSTEMS

Ziziphora tenuior has been used in Iranian folk medicine as an analgesic and for treament of digestive diseases.This study was designed to investigate the antinociceptive effects of hydroalcoholic extract of Z. tenuior on visceral pain and its possible involvement in opioidergic and serotoninergic systems in male albino N-MRI mice. Antinociceptive effect of was determined by writhing test as a model of visceral pain. Z. tenuior extract was administered intraperitonealy (ip) in doses of 50, 75 and 100 mg/kg and antinociceptive effects were compared with indomethacin (5mg/kg, i.p.) and control groups. The most effective dose of the extract was selected for the possible involvement of opioidergic and serotoninergic systems. 15 minutes before administration of the effective dose, animals were studied by pretreatment of opioid antagonist, naloxane (2mg/kg, i.p.) and serotoninergic antagonist, cyproheptadine (4mg/kg, i.p.) using writhing test. The results of this study showed that hydroalcoholic extract of Z. tenuior at 50, 75 and 100 mg/kg and indomethacin (5mg/kg) induced a significant reduction in pain response compared to the control group (p<0.05), while, pretreatment with naloxane and cyproheptadine inhibited some of the extract induced antinociceptive effects in comparison to control group (p<0. 05).This study indicated that some of the antiniciceptive properties of Z. tenuior are mediated by opioidergic and serotonergic mechanisms, which confirmed the traditional uses of the plant in the treatment of pain.