L-α-AA (10, 50, 150 nmol) was injected intrathecally 10 days after SNL. Mechanical allodynia, a major feature of chronic pain, is dose-dependently suppressed by the toxin. *, P<0.05; **, P<0.01, compared to vehicle (saline) control; ANOVA; n=6. Mechanical allodynia was tested using von Frey hairs. Reproduced, with permission, from (Zhuang et al., 2006a).