Antinociceptive effect of buprenorphine in mu1-opioid receptor deficient CXBK mice.
The antinociceptive effect of buprenorphine was examined in mu1-opioid receptor-deficient CXBK mice. I.p. administration of buprenorphine at a dose of 3 mg/kg produced marked antinociception in the tail-flick test in C57BL/6 mice, a progenitor strain of CXBK mice. The antinociceptive effect of buprenorphine in C57BL/6 mice was antagonized by pretreatment with either beta-funaltrexamine (beta-FNA), a mu-opioid receptor antagonist, or naloxonazine (NXZ), a selective mu1-opioid receptor antagonist. The antinociceptive effect of buprenorphine (3 mg/kg, i.p.) in CXBK mice was significantly less than that in C57BL/6 mice. Neither beta-FNA nor NXZ reduced the antinociceptive effect of buprenorphine in CXBK mice. There was no significant difference between the buprenorphine-induced antinociceptive effect in CXBK mice and NXZ-treated C57BL/6 mice. Furthermore, neither naltrindole, a selective delta-opioid receptor antagonist, nor norbinaltorphimine, a selective kappa-opioid receptor antagonist, had a significant effect on the antinociceptive effects of buprenorphine in both CXBK and C57BL/6 mice. These results support our previous hypothesis that mu1- rather than mu2-, delta- or kappa-opioid receptors are involved in the antinociceptive effects of buprenorphine.
Kamei
J
J
Department of Pathophysiology & Therapeutics, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan. kamei@hoshi.ac.jp
Sodeyama
M
M
Tsuda
M
M
Suzuki
T
T
Nagase
H
H
D000818:Animals; D002047:Buprenorphine / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009270:Naloxone / Q000031:analogs & derivatives / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D017450:Receptors, Opioid, mu / Q000172:deficiency / Q000187:drug effects*; D013045:Species Specificity
D009292:Narcotic Antagonists; D017450:Receptors, Opioid, mu; D009270:Naloxone; D002047:Buprenorphine; D009271:Naltrexone; C024524:beta-funaltrexamine; C034643:naloxonazine