The Antinociceptive Effects of Iranian Cobra Snake Venom using Formalin Test

There have been numerous reports of snake venoms being employed as analgesics in attempts to relieve severe pain associated with cancer، immune dysfunction and viral infections. This study investigates the antinociceptive effects of iranian cobra snake venom (Naja naja oxiana) in comparison with morphine and lidocain on laboratorial femal mice. This study has been done on 48 NMRI female mice of 18-20 g in weight. Antinociceptive activeity of snake venom was evaluated by formalin test. In this test، the animals were divided into 6 groups (each group consisting of 8 mice): Sham، positive Control (receiving morphine at dose of 5 mg/kg، and receiving lidocain at dose of 20 mg/kg)، and experimental groups receiving venom at doses of 1، 3 and 4/5 µg/mice. In all groups، the formalin test was recorded for 60 min after administration of venom and drugs in mice. Data were analyzed using one-way ANOVA and Tukey test. The results showed that the venom of Naja naja oxiana decreased nociception meaningfully in both acute and chronic phases. We also showed that this venom revealed even a better analgesic activity in comparison with morphine and lidocain. This study showed that the antinociceptive effect of the venom was mediated through central nervous system and peripheral mechanisms. Although details of the mechanism remain unclear، and further studies should be considered to demonstrate its therapeutic effects.