INVOLVEMENT OF OPIOIDERGIC AND SEROTONINERGIC SYSTEMS IN THE ANTINOCICEPTIV EEFFECT OF TANACETUM PARTHENIUM

Abstract

Tanacetum parthenium (T.p.) is used in folk medicine as a treatment wiedly. We<br><br>reported the analgesic effect of T.p. flowers and leaves previously. This study was<br><br>designed to find how this mechanism is occurred by T.p. flower extract.<br><br>Based on our previous study, the dose of 50 mg/kg i.p. of the aqueous extract has<br><br>analgesic effect on mice (NMRI) (20 ± 2 g) that was used for study. We studied<br><br>involvement of the opioidergic, serotoninergic,α-adrenergic systems separatly in antinociceptive<br><br>effect. 15 min before the administration of the extract, animals were<br><br>pretreated with drugs, including naloxane (5mg/kg, i.p.), serotoninergic antagonist<br><br>cyproheptadine (4 mg/kg, i.p.) and α-adrenergic antagonist phentolamine (20mg/kg,<br><br>i.p.)(n &gt; 6 in each group).<br><br>Pretreatment with naloxane increased pain percepation in the neurogenic phase of<br><br>formalin test compared to the control (p&lt;0.001). Moreover cyproheptadine increased<br><br>the sensation of pain in both phases (p&lt;0.05). Inhibition of α -adrenergic system was<br><br>not be able to attenuate the anti-nociceptive effect of the extract.<br><br>These results propose the involvement of sertoninergic and opioidergic systems in the<br><br>anti-nociceptive effect of the T.p. extract.