Fig. 6

Effect of the chronic treatment with vehicle (kolliphor 5% in saline, v/v, i.p.) or PEA-OXA (10 mg/kg, i.p.) on the release of biogenic amines in the hippocampus CA3 and LC neuron activity in sham and SNI mice. a, b The effect of vehicle or PEA-OXA on the extracellular level of norepinephrine (NE) and dopamine (DA) in the CA3 of sham and SNI mice. c The characteristic spike of a noradrenergic neuron of the LC with a long-lasting positive–negative waveform. d Displays a phasic activation followed by a long period of post-activation inhibition induced by a nociceptive pressure applied to the hind paw (PC). e The effect of medetomidine, an adrenergic alpha2 receptor agonist, and idazoxan, an adrenergic alpha2 receptor antagonist on the firing rate in the LC. f, g show the effect of vehicle or PEA-OXA on the tonic activity of LC neurons, in terms of firing rate and percentage of spikes in burst, in sham and SNI mice. h The number of noradrenergic neurons found in sham and SNI mice. i–l Examples of ratemater records which illustrate the effect of medetomidine on the firing rate of LC neurons in sham and SNI treated with vehicle or PEA-OXA. m, n The TH positive profiles in the LC neurons and relative quantification. Data are represented as mean ± SEM. Two-way ANOVA, followed by Tukey's post hoc test for multiple comparisons test was used for statistical analysis. p < 0.05 was considered statistically significant. Symbols indicate significant differences: **vs Sham/veh (p < 0.01), ***vs Sham/veh (p < 0.001), ****vs Sham/veh (p < 0.0001) and ^#vs SNI/veh (p < 0.05), ^##vs SNI/veh (p < 0.01), ^####vs SNI/veh (p < 0.0001), respectively