Binding affinity of agonists and antagonists at human adenosine receptor subtypes (K i values with 95% confidence intervals or ± S.E.M. in parentheses)
| A1 | A2A | A2B | A3 | Reference | |
|---|---|---|---|---|---|
| Agonists with unmodified ribose | |||||
| R-PIA | 2.0 (1–4.2) | 860 (480–1,540) | 16 (9.3–29) | —7-a | |
| 33,700 (±6,800) | —7-c | ||||
| 3,800 (±1,700) | —7-e | ||||
| S-PIA | 75 (42–134) | 7,800 (7,000–8,640) | 45 (33–61) | —7-a | |
| 62,800 (±21,600) | —7-c | ||||
| CPA | 2.3 (1.5–3.4) | 790 (470–1,360) | 43 (30–61) | —7-a | |
| 34,400 (±11,100) | —7-c | ||||
| 21,000 (±4,300) | —7-e | ||||
| CCPA | 0.8 (0.55–1.25) | 2,300 (2,000–2,700) | 42 (32–56) | —7-a | |
| 40,100 (±16,400) | —7-c | ||||
| 2-Cl-adenosine | 1.39 (1.28–1.51) | 180 (150–220) | 19 (14–28) | —7-i | |
| Agonists with 5′-modified ribose | |||||
| NECA | 14 (6.4–29) | 207-150 (12–35) | 6.27-150 (3.5–11) | —7-a | |
| 330 (±60) | —7-c | ||||
| 360 (±120) | —7-e | ||||
| CGS 21680 | 290 (230–360) | 27 (12–59) | 67 (50–90) | —7-a | |
| 361,000 (±21,000) | —7-c | ||||
| HENECA | 60 (50–72) | 6.4 (3.8–11) | 2.4 (2.0–2.9) | —7-b | |
| PENECA | 560 (480–650) | 620 (300–1,300) | 6.2 (5.1–7.5) | —7-b | |
| PHPNECA | 2.7 (1.7–7.1) | 3.1 (2.4–3.9) | 0.42 (0.17–1.0) | —7-b | |
| AB-MECA | 1,500 (1,300–1,800) | 3,600 (2,700–4,700) | 22 (20–24) | —7-a | |
| IB-MECA | 3.7 (1.8–7.7) | 2,500 (1,900–3,400) | 1.2 (0.96–1.5) | —7-a | |
| 54,000 (±5,600) | —7-c | ||||
| IAB-MECA | 8.5 (4.8–15) | 470 (300–740) | 0.64 (0.58–0.70) | —7-a | |
| Cl-IB-MECA | 115 (114–116) | 2,100 (1,700–2,500) | 11 (9.4–13) | —7-b | |
| Antagonists: xanthines | |||||
| DPCPX | 3.97-150 (3.5–4.2) | 129 (35–260) | 4,000 (2,600–6,000) | —7-a | |
| 50 (±3.7) | —7-c | ||||
| 51 (±6.1) | —7-e | ||||
| XAC | 29 (24–35) | 1 (0.58–1.7) | 92 (64–130) | —7-a | |
| 7.3 (±2.8) | —7-c | ||||
| 12 (±4.6) | —7-e | ||||
| MRS1754 | 400 (±190) | 500 (±11) | 2.0 (±0.31) | 570 (±180) | —7-f |
| MSX-2 | 2,500 (1,700–3,600) | 5.0 (±0.6) | >10,000 | —7-h | |
| Theophylline | 6,800 (4,100–11,000) | 1,700 (1,000–2,900) | 86,000 (74,000–101,000) | —7-a | |
| Antagonists: non-xanthines | |||||
| CGS 15943 | 3.5 (1.7–7.3) | 4.2 (2.6–6.6) | 51 (43–60) | —7-a | |
| 16 (±3.6) | —7-e | ||||
| SCH 58261 | 290 (210–410) | 0.6 (0.5–0.7) | >10,000 | —7-d | |
| ZM 241385 | 260 (190–390) | 0.8 (0.7–1.0) | >10,000 | —7-d | |
| 32 (±6) | —7-c | ||||
| MRE 3008F20 | 1,100 (±1,100) | 140 (±15) | 2,100 (±300) | 0.29 (±0.03) | —7-g |
↵7-150 Values are from saturation experiments.
↵7-a Klotz et al., 1998, transfected CHO cells; radioligands [3H]CCPA (A1), [3H]NECA (A2A and A3).
↵7-b Klotz et al., 1999, transfected CHO cells; radioligands [3H]CCPA (A1), [3H]NECA (A2A and A3).
↵7-c Linden et al., 1999, transfected HEK 293 cells; radioligand 125I-ABOPX.
↵7-d Ongini et al., 1999, transfected CHO cells (A1 and A2A) or HEK 293 cells (A2A and A3); radioligands [3H]DPCPX (A1), [3H]SCH 58261 (A2A), 125I-AB-MECA (A3).
↵7-e Ji and Jacobson, 1999, transfected HEK 293 cells; radioligand [3H]ZM 241685.
↵7-f Kim et al., 2000, transfected HEK 293 cells; radioligands 125I-ABA (A1), 125I-ZM 241685 (A2A),125I-ABOPX (A2B), 125I-AB-MECA (A3).
↵7-g Varani et al., 2000, transfected CHO cells; radioligands [3H]DPCPX (A1 and A2B), [3H]SCH 58261 (A2A), 125I-AB-MECA (A3).
↵7-h Sauer et al., 2000, transfected CHO cells; radioligand [3H]CHA (A1), [3H]CGS 21680 (A2A), [3H]NECA (A3).
↵7-i K.-N. Klotz and S. Kachler, unpublished, transfected CHO cells; radioligand [3H]NECA.