Effect of NTPDase1 and NTPDase2 on the observed pharmacological selectivity of the P2Y1 receptor The human P2Y1 receptor was coexpressed with either NTPDase1 or NTPDase2 in the same cell or P2Y1 receptor-expressing cells were cocultured with cells expressing either NTPDase1 or NTPDase2. Agonist-stimulated [3H]inositol phosphate accumulation was measured as described under Materials and Methods. The changes in apparent potency of agonists are expressed as fold-increases (+) or decreases (-) in the EC50 values compared with cells expressing the P2Y1 receptor alone.
| Agonist | P2Y1 Receptor EC50 | P2Y1 Receptor | |||
|---|---|---|---|---|---|
| NTPDase1 | NTPDase2 | ||||
| Cocultured | Coexpressed | Cocultured | Coexpressed | ||
| μM | |||||
| 2MeSADP | 0.1 ± 0.0 | 12.3 (+) | 11.0 (+) | 1.7 (+) | 1.4 (+) |
| ADP | 1.0 ± 0.2 | 46.6 (+) | 53.3 (+) | 1.1 (+) | 1.1 (+) |
| ATP | 4.3 ± 0.6 | 7.4 (+) | 11.3 (+) | 16.4 (-) | 18.6 (-) |
| ADPβS | 1.0 ± 0.4 | 1.2 (+) | 20.0 (-) | 1.2 (-) | 1.5 (-) |