Fig. 1. Effects of orally and intracerebroventricularly administered gabapentin after surgery in rats. The mechanical withdrawal threshold is presented over time. Both oral ( A ; 30–300 mg/kg) and intracerebroventricular ( B ; 10–100 μg/rat) gabapentin produced a dose-dependent increase in withdrawal threshold compared with vehicle. * P < 0.05 versus time 0 by one-way analysis of variance. Groups differ by two-way analysis of variance with 300 mg/kg > 100 mg/kg > 30 mg/kg > vehicle in A and with 100 > 30 > 10 = vehicle in B .