Table 3. Affinity (pKi) and Potency (pEC50) of Synthetic Adenosine and NECA Phenoxycyclopentyl Derivatives.
| compd | R1 | R2 | hA1R |
hA2AR |
hA2BR |
hA3R |
hA1R | rA1R | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| pEC50a | Emaxb | pEC50a | Emaxc | pEC50a | Emaxc | pEC50a | Emaxb | pKid | pKid | |||
| adenosine | 7.16 ± 0.23 | 51.09 ± 4.9 | 7.60 ± 0.11 | 21.53 ± 0.9 | 7.28 ± 0.12 | 59.07 ± 2.9 | 7.87 ± 0.23 | 24.71 ± 2.5 | 6.09 ± 0.06 | 6.06 ± 0.05 | ||
| 24 | –CH2OH | H | 8.98 ± 0.14* | 52.71 ± 3.1 | N.D.e | 4.90 ± 0.14* | 64.19 ± 5.4 | 5.78 ± 0.42* | 17.83 ± 3.7 | 6.84 ± 0.06* | 6.60 ± 0.02* | |
| 25 | –CH2OH | p-t-Bu | 7.74 ± 0.28 | 42.14 ± 5.1 | N.D.f | N.D. | N.R. | 6.35 ± 0.08 | 6.70 ± 0.05* | |||
| 26 | –CH2OH | m-OMe | 9.28 ± 0.10* | 56.74 ± 2.4 | 5.24 ± 0.55* | 17.25 ± 5.0 | N.D. | N.R. | 6.61 ± 0.07* | 6.56 ± 0.06* | ||
| 27 | –CH2OH | m-Br | 10.0 ± 0.24* | 30.55 ± 3.3* | N.D. | 4.63 ± 0.12* | 82.53 ± 6.2 | N.R. | 7.55 ± 0.11* | 6.94 ± 0.08* | ||
| 28 | –CH2OH | o-Cl | 9.03 ± 0.19* | 44.15 ± 3.6 | 5.96 ± 0.28* | 17.01 ± 2.2 | 5.31 ± 0.09* | 96.77 ± 4.4* | 6.73 ± 0.42 | 13.42 ± 2.4* | 7.17 ± 0.06* | 7.28 ± 0.04* |
| 29 | –CH2OH | m-Cl | 9.21 ± 0.19* | 38.25 ± 3.0 | 6.26 ± 0.34 | 13.63 ± 2.1 | 5.29 ± 0.07* | 96.93 ± 8.1* | 6.81 ± 0.47 | 11.77 ± 2.3* | 7.19 ± 0.07* | 7.36 ± 0.03* |
| 30 | –CH2OH | p-Cl | 8.19 ± 0.18* | 45.06 ± 3.6 | 4.86 ± 0.58* | 15.15 ± 5.5 | N.D. | 6.88 ± 0.60 | 12.5 ± 3.2* | 6.23 ± 0.11 | 6.22 ± 0.06 | |
| NECA | 8.96 ± 0.11 | 50.11 ± 2.4 | 7.95 ± 0.26 | 22.03 ± 2.4 | 7.20 ± 0.07 | 68.12 ± 2.0 | 7.83 ± 0.26 | 34.34 ± 3.7 | 6.61 ± 0.06 | 6.38 ± 0.04 | ||
| 49 | –CONHEt | H | 9.53 ± 0.20 | 32.68 ± 2.5* | 5.48 ± 0.42* | 15.41 ± 3.0 | 6.04 ± 0.09* | 87.99 ± 3.7* | 7.17 ± 0.16 | 51.24 ± 3.4* | 7.30 ± 0.05* | 7.41 ± 0.03* |
| 50 | –CONHEt | p-t-Bu | 7.81 ± 0.41* | 33.66 ± 6.1 | 4.84 ± 0.30* | 20.11 ± 3.8 | 4.77 ± 0.08* | 96.35 ± 5.0* | 6.63 ± 0.19* | 39.85 ± 3.2 | 6.35 ± 0.07 | 6.85 ± 0.05* |
| 51 | –CONHEt | m-OMe | 9.88 ± 0.29 | 39.71 ± 5.9 | 5.20 ± 1.11* | 5.16 ± 3.1* | 5.10 ± 0.07* | 84.76 ± 3.3 | 5.56 ± 0.14* | 59.38 ± 4.0* | 7.26 ± 0.14* | 6.85 ± 0.06* |
| 52 | –CONHEt | m-Br | 9.62 ± 0.35 | 39.71 ± 5.9 | 4.58 ± 0.87* | 11.48 ± 6.7 | 5.37 ± 0.11* | 61.12 ± 3.3 | 5.52 ± 0.12* | 68.26 ± 3.8* | 7.05 ± 0.16* | 6.82 ± 0.10* |
| 53 | –CONHEt | o-Cl | 9.91 ± 0.23 | 28.65 ± 2.7* | 5.67 ± 0.46* | 14.69 ± 3.2 | 6.22 ± 0.09* | 80.91 ± 3.1 | 7.00 ± 0.19* | 41.6 ± 3.3 | 7.39 ± 0.04* | 7.60 ± 0.04* |
| 54 | –CONHEt | m-Cl | 9.28 ± 0.28 | 34.67 ± 2.1 | 5.86 ± 0.41 | 13.32 ± 2.6 | 6.01 ± 0.09* | 78.81 ± 3.4 | 6.79 ± 0.14* | 44.20 ± 2.6 | 7.43 ± 0.05* | 7.51 ± 0.06* |
| 55 | –CONHEt | p-Cl | 7.99 ± 0.15 | 35.07 ± 2.5 | 4.86 ± 0.32* | 25.01 ± 5.2 | 5.10 ± 0.09* | 83.73 ± 4.5 | 6.92 ± 0.17* | 47.16 ± 3.3 | 6.86 ± 0.10 | 7.08 ± 0.04* |
The negative logarithm of the agonist concentration required to produce a half-maximal response in the cAMP accumulation assay in CHO-K1 cells stably expressing a human AR subtype. Forskolin is included in the assay (10 and 1 μM for A1R and A3R, respectively).
The % maximal inhibition of cAMP accumulation for each agonist. Forskolin is included in the assay (10 and 1 μM for A1R and A3R, respectively).
The % maximal accumulation of each agonist relative to 10 μM forskolin stimulation.
Binding affinity (pKi) determined through the NanoBRET binding assay in HEK293 cells stably expressing human or rat Nluc-A1R. The resulting concentration-dependent decrease in NanoBRET ratio at 10 min was used to calculate pKi.
N.D., not determined. Full dose–response curve was not feasible.
N.R., no response detected in the assay. All data are the mean ± SEM of at least three independent repeats conducted in duplicate. Statistical significance (*p < 0.05) determined using one-way ANOVA and Dunnett’s post-test, presented according to ref (31). Adenosine derivatives were compared to adenosine, while NECA derivatives were compared to NECA.