| Agonist . | EC50 (µM) . | nH . | Imax agonist/Imax ATP(%) . | n . |
|---|---|---|---|---|
| ATP | 32 ± 4 | 1.4 ± 0.1 | n/a | 15 |
| CTP | 370 ± 30 | 1.7 ± 0.1 | 105 ± 4 | 7 |
| 6-Cl−rTP | >300 | ND | ND | 5 |
| ITP | ND | ND | ND | 11 |
| isoGTP | ND | ND | ND | 10 |
| GTP | ND | ND | ND | 8 |
| UTP | 12,000 ± 480**** | 2.6 ± 0.2**** | 45 ± 3 | 11 |
| Agonist . | EC50 (µM) . | nH . | Imax agonist/Imax ATP(%) . | n . |
|---|---|---|---|---|
| ATP | 32 ± 4 | 1.4 ± 0.1 | n/a | 15 |
| CTP | 370 ± 30 | 1.7 ± 0.1 | 105 ± 4 | 7 |
| 6-Cl−rTP | >300 | ND | ND | 5 |
| ITP | ND | ND | ND | 11 |
| isoGTP | ND | ND | ND | 10 |
| GTP | ND | ND | ND | 8 |
| UTP | 12,000 ± 480**** | 2.6 ± 0.2**** | 45 ± 3 | 11 |
Concentration–response data (EC50) and Hill coefficient (nH) for ATP and a range of base-modified nucleoside triphosphate analogues (shown as mean ± SEM). Relative efficacy expressed as maximal current compared to that elicited by 1 mM of ATP and number of experiments (n) and are also shown (n/a: not applicable; ND, not determined). Significant differences were determined by one-way ANOVA with Dunnett’s test. ****, P < 0.0001.