Comparison of the effects of systemic administration of lacosamide and monosodium iodoacetate. These graphs show the effects of lacosamide (LCM; 3 and 30 mg/kg) on the evoked neuronal responses to electrical (a, b), dynamic brush (c, d), mechanical punctate (e, f) and thermal stimulation (g, h) of the peripheral receptive field in sham rats (n = 6, left panel) and monosodium iodoacetate (MIA) rats (n = 5, right panel). Neuronal responses evoked by Aβ- and C-fibres, dynamic brush, von Frey (vF) 8 to 60 g and 45°C to 48°C heat stimulation were significantly reduced by LCM in the MIA group only. Asterisks and bars denote statistically significant main effect (one-way repeated-measures analysis of variance (RM-ANOVA)). § denotes significance at 3 mg/kg, and * denotes significance at 30 mg/kg, compared with baseline control data (P < 0.05 by one-way RM-ANOVA with Bonferroni-corrected paired t-test). Values are mean ± SEM. PD, Postdischarge; Input, Baseline C-fibre-evoked response measure of afferent input and the resultant spinal neuronal response prior to central neuronal hyperexcitability evoked by subsequent stimuli; W, Wind-up, a frequency-dependent incremental increase in neuronal response to repetitive stimulation of C-fibres (that is, a measure of central neuronal hyperexcitability).