| First Author | Oakley SM | Year | 2003 |
| Journal | Eur J Pharmacol | Volume | 466 |
| Issue | 1-2 | Pages | 91-8 |
| PubMed ID | 12679145 | Mgi Jnum | J:102598 |
| Mgi Id | MGI:3607820 | Doi | 10.1016/s0014-2999(03)01531-0 |
| Citation | Oakley SM, et al. (2003) G-protein coupling of delta-opioid receptors in brains of mu-opioid receptor knockout mice. Eur J Pharmacol 466(1-2):91-8 |
| abstractText | Mu-opioid receptor knockout mice have been reported to show loss of some delta-opioid receptor function. We hypothesised that this is due to some delta-opioid receptors being uncoupled from G-proteins in the absence of the mu-opioid receptor. To address this possibility, we have used quantitative autoradiography to determine the binding of three delta-opioid receptor agonist ligands ([3H]deltorphin I, [3H] [R-Atc(3), Ile(5,6)]deltorphin II, [3H] 4-[(alpaR)-alpha-((2S,5R)-4-propyl-2,5-dimethyl-1-piperazinyl)-3-methoxybe nzyl]-N,N-diethylbenzamide (SNC-121)) and the delta-opioid receptor antagonist, [3H]naltrindole in the presence and absence of a GTP analogue, guanylylimidodiphosphate (GMPPNP) in the brains of mice lacking the mu-opioid receptor gene. Guanylylimidodiphosphate caused a decrease in the binding of the agonist ligands (to differing extents) and an increase in binding for the antagonist in wild-type controls. Overall, there were no major differences in the effects of guanylylimidodiphosphate for the agonist ligands in mu-knockout mice although a few structures showed a smaller sensitivity to the effects of this GTP analogue most notably for [3H]naltrindole. These findings suggest that in the majority of brain regions, G-protein coupling is unaltered in mu-opioid receptor knockout mice. |
