Table 3.
Affinity and selectivity towards σ1 and σ2 receptors.
| Compd. | X | R | Substitution |
Ki (µM)a |
Selectivity vs. σ1Rb | |
|---|---|---|---|---|---|---|
| σ1R | σ2R | |||||
| 1 | O | 6-OMe | 4' | 0.48 ± 0.05 | 1.78 ± 0.43 | 3.7 |
| 2 | O | 6-OH | 4' | 0.38 ± 0.05 | 1.60 ± 0.28 | 4.2 |
| 4 | O | 5,7-diOH | 4' | 0.51 ± 0.07 | > 3.0 | > 5.9 |
| 6 | O | 6,7-diOMe | 3' | 0.53 ± 0.07 | 1.30 ± 0.35 | 2.5 |
| Pentazocine | 0.015 ± 0.003 | n.d. | ||||
| DTG | n.d. | 0.054 ± 0.008 | ||||
aResults are expressed as Ki (µM) and are the mean ± SEM of the experiments repeated in triplicates. bSelectivity vs. σ1R was calculated as Kiσ2R/Kiσ1R. DTG: 1,3-di-o-tolylguanidine.