Fig. 1. Dose–effect curves after the administration of 2.5% lidocaine intrathecally and epidurally. The x axis shows the volume of 2.5% lidocaine, and the y axis shows the area under the curve (AUC). Data are presented as mean ± SEM. •= intrathecal; ○= epidural; %MPE = percent maximal possible effect; TF = tail flick.