Effect of selenium compound (selol) on the opioid activity in vincristine induced hyperalgesia.

PURPOSE: Effect of organoselenium compound (selol), on antinociceptive action of opioid agonists in vincristine neuropathic pain model was investigated. METHODS: The changes in pain thresholds were determined using mechanical stimuli--the modification of the classic paw withdrawal test described by Randall-Selitto. RESULTS: Daily administration of VIN (70 microg/kg, iv) resulted in progressive decrease of pain threshold. Neither morphine, fentanyl nor buprenorphine administered alone in 5 consecutive days modified the vincristine-induced hyperalgesia, whereas selol slightly increased the nociceptive threshold. Co-administration of selol with opioids markedly enhanced the analgesic activity of all three investigated compounds. CONCLUSIONS: Therefore, concomitant administration of selenium and opioids may be beneficial in terminal neoplastic states.

Effect of bradykinin receptor antagonists on vincristine- and streptozotocin-induced hyperalgesia in a rat model of chemotherapy-induced and diabetic neuropathy.

The role of bradykinin receptor blockade in the development of neuropathies caused by diabetes mellitus and vincristine was examined. The effects of a potent and selective B(1) receptor antagonist (des-Arg(10)-HOE 140) as well as a specific antagonist of B(2) receptors (HOE 140) were investigated. Both agents significantly decreased hyperalgesia caused otherwise by vincristine. In a diabetic neuropathy model, both agents almost completely suppressed hyperalgesia in the first 10 days of the study. However, from day 11 after administration of streptozotocin, the action of des-Arg(10)-HOE 140 was significantly weaker than that of HOE 140. The results of the study suggest involvement of both B(1) and B(2) receptors in transmission of nociceptive stimuli in the vincristine-induced as well as diabetic neuropathy model.