Figure 3 - Differences in the intensity of response of chronically cannulated (Cn), naive (Nv) and sham-operated (Sh) rats during phase 1 of the formalin test. Formalin was administered at different doses of 0.3, 1, and 5%. Each bar is the mean ± SEM number of flinches of 6-12 animals, measured for 10 min after the nociceptive stimulus. Data were analyzed by one-way ANOVA followed by Duncan's test. *P<0.05 compared to normal or Sh animals.