Fig. 3. Effect of intrathecal pretreatment with vehicle ARC239 (α2non-A-subtype–preferring antagonist) (A , top ) and BRL44408 (α2A-subtype–preferring antagonist) (B , bottom ) on withdrawal thresholds before and after paw incision and after intrathecal injection of 59 nmol ST91. Each symbol represents the mean ± SD of 5–9 animals. *P < 0.05 versus preincision and control times; †P < 0.05 versus vehicle; $ P < 0.05 versus 0.94 nmol ARC.