Antitussive effect of (+/-) pentazocine in diabetic mice is mediated by delta-sites, but not by mu- or kappa-opioid receptors.
The effects of streptozotocin-induced diabetes on the antitussive effect of (+/-) pentazocine were examined in mice. Intracerebroventricular (i.c.v.) administration of (+/-) pentazocine produced a dose-dependent antitussive effect in both diabetic and non-diabetic mice. There were no significant differences in the antitussive effect of (+/-) pentazocine in diabetic and non-diabetic mice. The antitussive effect of i.c.v. (+/-) pentazocine was partially, but significantly, reduced in non-diabetic mice following pretreatment with either beta-funaltrexamine, a selective mu-opioid antagonist, or rimcazole, a specific sigma-site antagonist. The antitussive effect of (+/-) pentazocine in diabetic mice was significantly antagonized by pretreatment with rimcazole. However, beta-funaltrexamine had no effect on the antitussive effect of (+/-) pentazocine in diabetic mice. Furthermore, nor-binaltorphimine, a selective kappa-opioid receptor antagonist, had no significant effect on the antitussive effect of (+/-) pentazocine in either non-diabetic or diabetic mice. These results suggest that although the antitussive effect of i.c.v. (+/-) pentazocine in non-diabetic mice is mediated by both mu-opioid receptors and sigma-sites, in diabetic mice this effect is mainly mediated by sigma-sites.
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
D000818:Animals; D000996:Antitussive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental; D007276:Injections, Intraventricular; D051379:Mice; D008813:Mice, Inbred ICR; D010423:Pentazocine / Q000008:administration & dosage / Q000494:pharmacology*; D017465:Receptors, Opioid, delta / Q000819:agonists*; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D013311:Streptozocin
D000996:Antitussive Agents; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D013311:Streptozocin; D010423:Pentazocine