Table 2. Binding Affinities and Functional Activities of SalA-VS-07 and SalA-VS-08 at the Human KORa.
| binding affinityb | G protein activationc |
β-arrestin2
recruitmentd |
|||
|---|---|---|---|---|---|
| Ligand | Ki (nM) | EC50 (nM) | Emax (%) | EC50 (nM) | Emax (%) |
| SalA-VS-07 | 423 ± 97 | 181 ± 49 | 48 ± 7 | –e | |
| SalA-VS-08 | 68.5 ± 5.5 | 854 ± 60 | 108 ± 8 | –e | |
| SalA | 2.66 ± 0.75 | 11.8 ± 3.5 | 100 ± 1 | 14.5 ± 2.8 | 90.1 ± 1.0 |
| U69,593 | 1.56 ± 0.34 | 16.3 ± 3.5 | 100 | 85.0 ± 5.7 | 100 |
a
Emax (%) values represent the percentage relative to the maximal effect of U69,593 (as 100%). Values represent the mean ± SEM (n = 3–4).
b
Determined in the radioligand competitive binding assays using membranes from CHO cells stably expressing the human KOR.
c
Determined in the [35S]GTPγS binding assays using membranes from CHO cells stably expressing the human KOR.
d
Determined in the PathHunter β-arrestin2 recruitment assay with U2OS cells coexpressing the hKOR and the enzyme acceptor tagged β-arrestin2 fusion protein.
e
Denotes no measurable activity up to 10 μM.