Figure 5.

Effects of EP receptor antagonists on PGE₂. Macrophages were pre‐incubated with indomethacin (1 μM) for 30 min and then without or with EP receptor‐selective antagonists (300 nM) for 1 h and then without or with PGE₂ for 30 min before challenge with LPS (1 ng·mL⁻¹) for 22 h after which TNF‐α was measured in the supernatants. The effects on PGE₂ of (A) the EP₄ receptor‐selective antagonist CJ‐042 794, (B) the EP₂ receptor‐selective antagonist PF‐04 418 948, (C) the EP₄ receptor‐selective antagonist L‐161,982 and (D) CJ‐042 794 with and without PF‐04 418 948 were evaluated. Results are expressed as the % inhibition of control TNF‐α releases which were, in the absence and presence of antagonist respectively, (A) 2646 ± 562 and 2582 ± 496 pg mL⁻¹, (B) 2912 ± 532 and 2881 ± 507 pg·mL⁻¹, (C) 2756 ± 882 and 2873 ± 862 pg·mL⁻¹ and (D) 2672 ± 972 to 2212 ± 799 pg·mL⁻¹. Data shown are means ± SEM for five (A, B and D) and six (C) experiments respectively.