Effect of PFE on cold hyperalgesia, assessed by the tail immersion test, in Tibial and Sural nerve Transection (TST)-induced neuropathic pain. Values are mean ± S.E.M. n = 6 rats per group. a = P < 0.05 vs. sham control group. b = P < 0.05 vs. TST group. c = P < 0.05 vs. PFE 100 + TST. d = P < 0.05 vs. PFE 300 + TST. e = P < 0.05 vs. L-NAME + PFE (300 mg/kg) + TST.