RESUMO
BACKGROUND: Reactive oxygen species (ROS) are critically involved in generating pain in various painful conditions, including neuropathic and inflammatory pain. This experiment was conducted in order to assess the antinociceptive effects of vitamin E in the modulation of pain in rats subjected to the formalin test. METHODS: Five percent formalin was injected into the hind paw after intraperitoneal injection of either vitamin E 1 g/kg dissolved in olive oil or olive oil alone. The Number of flinches were measured in a 5 minute interval for 1 hour. RESULTS: Formalin injected into the left hind paw induced a biphasic nociceptive behavior. Intraperitoneal injection of vitamin E diminished the nociceptive behavior during phase 1 and 2. CONCLUSIONS: Systemic administration of vitamin E produces analgesia in a rat model of formalin-induced hyperalgesia. Furthermore, vitamin E affects pain of peripheral origin.