Hypericumperforatum L. Showed Antinociceptive Effects Through Opioidergic And Serotonergic Systems

There are some reports concerning the antidepressant effects of Hypericumperforatum L.(Hp), but there are few studies indicating its antinociceptive effects of Hp. For assessment of its site of antinociceptive action and related systems, Hp was filtered and administered both intrathecally (i.t.) and intracerebroventriculary(i.c.v.). For evaluation of probable role of serotonergic and opioidergic systems, Methysergide (non-selective antagonists of serotonergic systems) andnaloxone hydrochloride (antagonist of opioidergic system) were used respectively. In central administration, the Hp(1 and 2 mg/rat, i.t.) induced analgesia in the tail flick and both phase of formalin test. The i.c.v. administration of Hp (2mg/rat) produced analgesia in both phases of formalin test, while it had no effect on tail flick latency. Methysergide pretreatment inhibited antinociceptive effects of Hp in both phases of formalin and tail flick tests. Naloxone inhibited antinociceptive effects of Hp in both phase of formalin test, while it had no effect on tail flick latency. The results showed that central administration its spinal effect seems be more potent than its cerebral effect. It seems that part of antinociceptive effect of Hp it’s related to serotonergic and opioidergic systems.