Fig. 4. Effects of orally administered donepezil after spinal nerve ligation (SNL) in rats. The mechanical withdrawal threshold is presented over time. Oral donepezil (1–10 mg/kg, n = 6–8) 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 10 mg > (2.5 mg/kg, 1 mg/kg, vehicle) and 5 mg/kg > (1 mg/kg, vehicle).