Effects of diabetes on the antinociceptive effect of (+/-)pentazocine in mice.
The antinociceptive effect of (+/-)pentazocine was examined in streptozotocin-induced diabetic mice. Although intracerebroventricular (i.c.v.) administration of (+/-)pentazocine (10 nmol) produced a significant antinociceptive effect in both non-diabetic and diabetic mice, the antinociceptive effect of (+/-)pentazocine was greater in diabetic mice than in non-diabetic mice. The antinociceptive effects of (+/-)pentazocine in both diabetic and non-diabetic mice were significantly antagonized by s.c. administration of nor-binaltorphimine, a selective kappa-opioid receptor antagonist. On the other hand, the antinociceptive effects of (+/-)pentazocine were potentiated when non-diabetic mice were pretreated with beta-funaltrexamine, a selective mu-opioid receptor antagonist. Furthermore, there was no significant difference in the antinociceptive effect of (+/-)pentazocine between diabetic mice and beta-funaltrexamine-treated non-diabetic mice. These results suggest that the hypo-responsiveness of mu-opioid receptors may account for the enhanced kappa-opioid receptor-mediated antinociceptive effect of (+/-)pentazocine in diabetic mice.
Kamei
J
J
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Iwamoto
Y
Y
Misawa
M
M
Nagase
H
H
Kasuya
Y
Y
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004357:Drug Synergism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects*; D010423:Pentazocine / Q000494:pharmacology*; D017473:Receptors, Opioid, kappa / Q000037:antagonists & inhibitors; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors
D000700:Analgesics; D009292:Narcotic Antagonists; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; C051844:norbinaltorphimine; D009271:Naltrexone; C024524:beta-funaltrexamine; D010423:Pentazocine