Potency (EC50) and affinity (Kd) of δ-opioid ligands assessed in cAMP accumulation and radioligand binding assays
| Potency (EC50) | Affinity (Kd) | Efficiency Ratio (Kd/EC50) | Affinity (Kd) after ICI174869 | |
|---|---|---|---|---|
| TICPΨ | 6 ± 0.3 pM | 53 ± 11 pM | 9 | 91 ± 18 pM |
| ICI174864 | 72 ± 6 pM | 72 ± 1 nM | 1000 | 85 ± 2 nM |
| Naltrindole | N.A. | 152 ± 57 pM | N.A. | 136 ± 56 pM |
| TIPP | N.A. | 145 ± 24 pM | N.A. | 133 ± 22 pM |
| Bremazocine | 727 ± 65 pM | 2.7 ± 0.3 nM | 87 | 2.1 ± 0.3 nM |
| DPDPE | 21 ± 1 pM | 1.2 ± 0.5 nM | 57 | 120 ± 42 pM1-150 |
Values were obtained by nonlinear regression analysis as described under Experimental Procedures and are expressed as mean ± S.E.M. of four to six independent experiments.
N.A., not assessed; parameter estimation not possible within acceptable reliability (α = 0.05).
↵1-150 p < 0.05.