Figure 2.

Role of COX-2 and PGE₂ in ceramide-induced hyperalgesia. A, B) When compared to baseline values at t = 0 h, intraplantar injection of C₂-ceramide (10 μg) led to a significant increase in COX-2 (A), but not COX-1 (B), expression by 2 h, which was sustained through 5 h, as measured by Western blot analysis. Top panels: bands are representative replicates of separate animals (n=3 rats) taken from the same gel and exposure. Bottom panels: band densities were normalized to α-tubulin (%COX-1 or -2/tubulin). C) Increased COX-2 corresponded with a significant increase in production of PGE₂ at 2 h, as measured in paw fluids (n=4 rats). Results are expressed as means ± se. *P < 0.05, **P < 0.01, ***P < 0.001 vs. t = 0 h; ANOVA with Dunnett's post hoc test (A, B) or unpaired Student's t test (C).