Species differences in μ- and δ-opioid receptors
The μ opioid receptor ligand [D-Ala 2, NMePhe 4, Gly-ol 5]enkephalin (DAGO) and δ opioid receptor ligand [D-Pen 2, D-Pen 5] enkephalin (DPDPE) show similar specificity in competition binding studies in whole brain homogenate in rat and mouse. However, in saturation studies, the density and affinity...
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Veröffentlicht in: | European journal of pharmacology 1991-01, Vol.193 (1), p.105-108 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The μ opioid receptor ligand [D-Ala
2, NMePhe
4, Gly-ol
5]enkephalin (DAGO) and δ opioid receptor ligand [D-Pen
2, D-Pen
5] enkephalin (DPDPE) show similar specificity in competition binding studies in whole brain homogenate in rat and mouse. However, in saturation studies, the density and affinity of DPDPE binding sites were substantially greater in the mouse. There was no difference between the mouse and rat in the density and affinity of DAGO sites. Results from dose-response studies for analgesia using the same ligands administered i.c.v. in both species paralleled the binding studies. DAGO was approximately 2 times more potent in the mouse compared to the rat; while DPDPE was more than 15 times more potent in the mouse. Thus, binding capacity and affinity differences appear to be related to the functional potency of the μ and δ ligands in the two species. These results suggest that the difference in potency of DPDPE between rat and mouse is related to the differences in brain δ opioid receptors. |
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ISSN: | 0014-2999 1879-0712 |
DOI: | 10.1016/0014-2999(91)90207-7 |