Fig. 1. Effect of intravenous (iv) injection of 10–30 mg/kg pregabalin (n = 10) or R -3-isobutylgaba (n = 8) on mechanical thresholds determined by paw withdrawal response to von Frey filaments. The timing of three injections is indicated by arrows. Data are presented as mean ± SEM. *P < 0.05 versus  pretreatment control.