PGE₂-G produced hyperalgesia in HbAA-BERK mice. PGE₂-G (2.3 nmol/10 µL, intraplantarly) was compared with the vehicle used for the pool of EP receptor antagonists (ratio of DMSO to ethanol to saline, 30%:1%:60%,10 µL, intraplantarly). (A) PGE₂-G increased the frequency of withdrawal to a mechanical stimulus (3.9 mN). Coinjection of PGE₂-G with vehicle or a pool of EP1, EP2, EP3, and EP4 receptor antagonists (SC51089, AH6809, L798106, and L161982, respectively, 20 nmol each, intraplantarly) did not reduce the effect of PGE₂-G. Vehicle alone had no effect in HbAA-BERK mice. Two-way ANOVA for repeated measures demonstrated a significant treatment × time interaction (F[10, 106] = 2.67; P = .006, N = 8-9 mice per group). *Different from baseline (BL) and vehicle values at P < .004; Bonferroni t test. (B) The same pool of EP antagonists was ineffective in suppressing mechanical hyperalgesia in HbSS-BERK mice (F[1, 64] = 0.98; P = .326, 2-way ANOVA for repeated measures, N = 6-9 mice per group). (C) The efficacy of the pool of antagonists was validated against hyperalgesia evoked by PGE₂ (9.8 nmol, intraplantarly) in naive C3H mice (2-way ANOVA for repeated measures (F[3, 80] = 8.88; P = .001, N = 5-6 mice per group). *Different from BL values at P < .013. #Different from PGE₂ plus antagonists at P = .017; Bonferroni t test. (D) PGE₂ increased cAMP in primary cultures of dissociated DRGs. The pool of EP receptor antagonists (10 μM per antagonist) blocked the effect of PGE₂. Data are presented as picomoles of cAMP per well. *Different from other treatment groups and vehicle (V; ratio of DMSO 0.2% to ethanol 0.04% to saline 99.76%). Data were transformed to log₁₀ for parametric statistical analysis. (F[3, 31] = 15.393; P < .001, 1-way ANOVA, N = 6 wells per treatment across 2 cultures).