Fentanyl and morphine interactions with opioid receptor subtypes
Experiments were conducted as described in the text.
| Drug | CHO-rMOR [3H]DAMGO Binding | CHO-hKOR [3H]U69,593 Binding | CHO-hDOR [3H]DPDPE Binding |
|---|---|---|---|
| Ki (nM) ± S.E.M. (n) | Ki (nM) ± S.E.M. (n) | Ki (nM) ± S.E.M. (n) | |
| Hill Slope ± S.E.M. | Hill Slope ± S.E.M. | Hill Slope ± S.E.M. | |
| Fentanyl | 0.35 ± 0.05 (16) | 125 ± 15 (14) | 244 ± 20 (12) |
| −0.78 ± 0.05 | −0.95 ± 0.05 | −1.07 ± 0.04 | |
| Morphine | 0.58 ± 0.8 (19) | 27 ± 3 (15) | 178 ± 14 (12) |
| −0.97 ± 0.05 | −0.98 ± 0.04 | −1.06 ± 0.04 | |
| [35S]GTPγS Binding | [35S]GTPγS Binding | [35S]GTPγS Binding | |
| EC50 (nM) ± S.E.M. (n) | EC50 (nM) ± S.E.M. (n) | EC50 (nM) ± S.E.M. (n) | |
| % Max DAMGO Stimulation ± S.E.M. | % Max U69,593 Stimulation ± S.E.M. | % Max DPDPE Stimulation ± S.E.M. | |
| Fentanyl | 18 ± 4 (12) | 389 ± 41 (14) | 1256 ± 153 (13) |
| 92% ± 4% | 85% ± 5% | 71% ± 5% | |
| Morphine | 38 ± 6 (13) | 47 ± 6 (12) | 789 ± 92 (13) |
| 86% ± 3% | 94% ± 4% | 89% ± 4% |
hDOR, human δ opoid receptor; hKOR, human κ opioid receptor; n, number of independent experiments, each conducted with duplicate determinations; rMOR; rat μ opioid receptor.