Fig. 1. Effects of intraplantar nerve growth factor (NGF) on difference in hind paw withdrawal latency: control groups. (A ) Intraplantar NGF with vehicle control intraperitoneal treatments is associated with a reduction in withdrawal latency to a noxious thermal stimulus expressed as a difference from baseline. A negative deflection is consistent with a thermal hyperalgesia. There is no difference between the three groups of vehicle control (vehicle for anandamide groups: soya emulsion, vehicle for palmitoylethanolamide group: dimethyl sulfoxide (DMSO), vehicle for capsazepine groups: 0.9% NaCl) (P > 0.05, two-way ANOVA, n = 5 in all groups). (B ) Plot demonstrating pooled data, mean difference in withdrawal latency (± SEM) against time.