Effects of vehicle (0.05% DMSO in aCSF) or SA (2 mg/kg, i.p.) repeated treatment on the onset (A), duration (B) and evoked frequency (C) of NS neurons 3 or 7 days after the injection of saline or formalin into the hind-paws. Each point represents the mean ± S.E.M of 6–8 neurons of different treated groups of mice. * indicates statistically significant differences vs veh/saline and # indicates statistically significant differences versus veh/form. P values <0.05 were considered statistically significant (one-way ANOVA followed by Student-Newman Keuls). Ratemeters show the responses to a noxious stimulation (von Frey filaments 97.8 mN/2 sec) of a single representative NS neuron in mice receiving veh/saline (D), veh/form (E) or SA/form (F). Black triangles indicate the noxious stimulation on mouse hind-paw. Scale bar indicates 5 min intervals for ratemeter records.