Table 1.
Affinities of EP3 antagonists in human recombinant prostanoid receptor/Ca2+ flux (FLIPR) assays
| Human prostanoid receptor | ||||||||
|---|---|---|---|---|---|---|---|---|
| DP1 | EP1 | EP2 | EP3 | EP4 | FP | IP | TP | |
| Standard agonist | BW-245C (7.90 ± 0.07) | PGE2(9.16 ± 0.10) | PGE2(8.27 ± 0.03) | PGE2(8.90 ± 0.13) | PGE2(9.29 ± 0.04) | 17-Phenyl PGF2α(8.05 ± 0.08) | Carbacyclin (7.18 ± 0.30) | U-46619 (9.54 ± 0.21) |
| Antagonist | pA2 | |||||||
| (DG)-3ap | <5.0 | 6.02 | <5.0 | 8.30 | 5.67 | <5.0 | 5.06 | <5.0 |
| L-826266 | 5.34 | 5.14 | <5.0 | 7.97 | 5.74 | <5.0 | <5.0 | 6.39 |
| pKi | ||||||||
| L-798106 | – | – | – | 7.77 | – | – | – | – |
Prostanoid receptor and chimeric G-protein were transfected into HEK-293 EBNA cells to facilitate Ca2+ signalling (FLIPR assay). Standard agonists: pEC50 values in parentheses (mean ± SEM, n= 6). pA2 values are single point estimates (10 µM antagonist) under Schild protocol (n= 3). Lower section: FLIPR assay involving inhibition of E80 response to PGE2 in U2OS carrier cell; pKi calculated using the unmodified Cheng–Prusoff equation (Jugus et al., 2009).
Affinities for the EP3 receptor are shown in bold type.
FLIPR, fluorimetric imaging plate reader.