Table 2.
Binding affinities (hA1, hA2A, hA3) and functional parameters (hA2B) of the 6-(heteroaryl-carbonyl)-hydrazino-NECA derivatives 19–26 at the human adenosine receptors expressed in CHO cells [79, 80]
| R | R′ | hA1 a K i (nM) | hA2A b K i (nM) | hA2B c EC50 (nM) | hA3 d K i (nM) | |
|---|---|---|---|---|---|---|
| NECA | 18.3 ± 2.5 | 12.5 ± 2.8 | 160 ± 20 | 34.6 ± 3.3 | ||
| 19 | H | 2-Furyl | 1050 ± 132 | 1550 ± 165 | 82 ± 10 | > 5000 (23%) |
| 20 | H | 5-Bromo-furan-2-yl | 780 ± 34 | 1200 ± 135 | 369 ± 42 | > 5000 (13%) |
| 21 | H | 5-Methyl-furan-2-yl | 700 ± 25 | 1600 ± 147 | 227 ± 18 | > 5000 (15%) |
| 22 | H | 5-Methyl-thiophen-2-yl | 1100 ± 124 | 2100 ± 185 | 273 ± 12 | > 5000 (19%) |
| 23 | Cl | 2-Furyl | 3500 ± 275 | 4950 ± 356 | 210 ± 13 | > 5000 (26%) |
| 24 | Cl | 5-Methyl-thiophen-2-yl | 2600 ± 194 | 4100 ± 390 | 175 ± 20 | > 5000 (17%) |
| 25 | Cl | Thiophen-3-yl | 933 ± 76 | 3300 ± 315 | 450 ± 29 | > 5000 (18%) |
| 26 | Cl | Thiophen-2-yl | 737 ± 46 | 1700 ± 180 | 200 ± 20 | > 5000 (12%) |
aDisplacement of specific [3H]CHA binding at human A1 receptors expressed in CHO cells. bDisplacement of specific [3H]CGS21680 binding at human A2A receptors expressed in CHO cells. ccAMP assay in CHO cells expressing human A2B adenosine receptors EC50 (nM). dDisplacement of specific [125I]ABMECA binding at human A3 receptors expressed in CHO cells. The percentages in the parentheses indicate the % of displacement of the new tested compounds in the binding experiments (5 μM). Data are expressed as geometric means with 95% confidence limits. The data are expressed as mean ± SEM.