Table 2.
Receptor binding affinities (Ki) of R-6 and its analogs at µ-, δ- and κ-opioid receptor
| No | Kia [nM] | ||
|---|---|---|---|
| MOR | DOR | KOR | |
| R-6 | > 1000 | 11.47 ± 2.25 | > 1000 |
| 1 | 598.55 ± 84.49 | 91.72 ± 29.69 | > 1000 |
| 2 | > 1000 | > 1000 | > 1000 |
| 3 | > 1000 | 734.21 ± 31.27 | > 1000 |
| 4 | > 1000 | > 1000 | > 1000 |
| 5 | 712 ± 100.51 | 13.13 ± 3.08 | > 1000 |
| 6 | > 1000 | > 1000 | > 1000 |
| 7 | > 1000 | 773.33 ± 136.88 | > 1000 |
aBinding affinities were determined by competitive displacement of the selective radioligands, [3H]DAMGO (µ-opioid receptor), [3H][Ile5,6]deltorphin-2 (δ-opioid receptor), and [3H]U-69593 (κ-opioid receptor) using commercial membranes of CHO cells transfected with human opioid receptors. All values are expressed as the mean ± SEM of four independent experiments performed in duplicate