Fig. 2. Effect of SNL or sham surgery, when performed within 24h of delivery, on withdrawal threshold. Withdrawal threshold ipsilateral (A ) or contralateral (B ) to SNL or sham surgery in virgin, nonpregnant and in postpartum rats when surgery was performed within 24 h of delivery. Data are presented as mean ± SD, Bonferroni’s Multiple Comparison Test: *P < 0.05 comparing postpartum SNL with nonpregnant SNL; ^P < 0.05 comparing postpartum SNL with postpartum Sham, &P < 0.05 comparing postpartum SNL with nonpregnant Sham; ^P < 0.05 comparing nonpregnant SNL with nonpregnant Sham, @P < 0.05 comparing nonpregnant Sham with postpartum Sham, #P < 0.05 comparing nonpregnant Sham with postpartum SNL. SNL = spinal nerve ligation.