Effect of selol on the opioids activity in streptozotocin induced hyperalgesia.

We examined the effect of the opioid receptor agonists and the effect of an antioxidant selol, which is an organoselenium compound on antinociceptive action of opioid agonists in diabetic neuropathic pain model. Streptozotocin (STZ) induced hyperglycemia accompanied by a prolonged decrease in nociceptive threshold is considered a useful model of experimental hyperalgesia. The changes in pain thresholds were determined using mechanical stimuli--the modification of the classic paw withdrawal Randall-Selitto test. Neither morphine, fentanyl nor buprenorphine administered alone in 7 consecutives days modified the STZ induced hyperalgesia, whereas selol slightly increased the nociceptive threshold. Pretreatment with selol markedly enhanced the analgesic activity of all three investigated opioids. Concomitant administration of selol and opioids in alleviation of neoplastic pains seems to be justified.