Figure 6.

Effects of specific opioid antagonists on neuropathic pain behavior in BAMBI^−/− mice. Representative graphs showing the behavioral manifestations of neuropathic pain (mechanical allodynia) evaluated with von Frey monofilaments, on day 14 after sciatic nerve crush injury (triangles), and the effect of pretreatment with selective opioid antagonists before performing the von Frey test (open circles). The antagonistic effect achieved by subsequent naloxone administration is also shown (filled circles). Values are the mean ± SEM percentage of hindpaw withdrawals elicited by mechanical stimuli of increasing strength. The selective antagonist of δ-opioid receptors, naltrindole (top graph), fully reversed the anti-allodynic phenotype of BAMBI^−/− mice, whereas the μ-opioid (β-FNA) and κ-opioid (nor-BNI) selective antagonists were much less effective.