Figure 1 - Comparison of the intensity of mechanical hyperalgesia in response to increasing doses of carrageenin (Cg) or PGE2 in chronically cannulated (Cn, triangles), naive (Nv, circles) and sham-operated (Sh, squares) rats. The intensity of hyperalgesia was measured 1 h (panel A) and 3 h (panel B) after the different doses of carrageenin (2.5-100 µg, intraplantar (ipl)). Panel C shows the intensity of hyperalgesia measured 3 h after an ipl injection of PGE2 (5-100 ng/ml). The data (mean ± SEM for five animals per group) were analyzed by one-way ANOVA followed by Duncan's test. *P<0.05 compared to Nv and Sh animals.