Results of behavioral test. (A) Results of behavioral tests in rats operated upon to create unilateral chronic constriction injury (CCI) of the sciatic nerve and (B) in sham-operated rats. Progressive development of evoked mechanical and thermal hyperalgesia was found in the ipsilateral hind paws of CCI rats. Transient thermal hyperalgesia was present bilaterally in both hind and fore paws 3 days after the sham operation. Data are expressed as mean ± SD of withdrawal thresholds (grams) and withdrawal latency (seconds) of mechanical and thermal hyperalgesia, respectively. Symbols identical to graph lines indicate significant differences (P<0.05) compared with measurements taken 1 day before operation.