Skip to main content
. 2022 Mar 4;145(7):2293–2300. doi: 10.1093/brain/awac085

Figure 3.

Figure 3

Ablation of coerulean noradrenergic fibres does not affect basal spinal convergent neuron activity or DNIC expression. (A) A PACT-cleared 500 µm thick lumbar spinal cord section (saline versus DSP4-treated rats) evidences a decrease in tyrosine hydroxylase (TH) immunolabelled fibres in the superficial but not deep dorsal horn (SDH/DDH). (B) DSP4 treatment did not impact WDR neuron sensory coding nor DNIC expression. Quantification of (C) brush and (D) von Frey evoked action potentials in saline and DSP4 treated rats. Brush and von Frey: mean ± SEM of N = 6 animals per group, n = 15 cells per group; unpaired t-test performed on n: P > 0.05 (brush); two-way ANOVA (von Frey) performed on n, (von Frey) P < 0.0001, F(2,30) = 128.7, (DSP4) P > 0.05, F(1,15) = 1.851. (E) Percentage of inhibition after DNIC activation as shown in (B). DNIC: mean ± SEM of N = 6 animals per group, n = 15 cells per group; two-way ANOVA performed on n, (DSP4) P > 0.05, F(1,15) = 0.2105. (F) Analogously to DSP4 treatment, ipsilateral LC microinjection of 2% lidocaine (marked by lucifer yellow) does not affect WDR neuronal activity nor DNIC expression, as quantified in (G) for brush and (H) for von Frey. Brush: mean ± SEM of N = 5 animals per group, n = 5 cells per group; paired t-test performed on n: P > 0.05. von Frey: mean ± SEM of N = 6 animals per group, n = 6 cells per group; two-way ANOVA performed on n, (von Frey) P < 0.001, F(2,10) = 23.97, (DSP4) P > 0.05, F(1,5) = 0.78. (I) Percentage of inhibition after DNIC activation as shown in (J). DNIC: mean ± SEM of N = 6 animals per group, n = 6 cells per group; two-way ANOVA performed on n, [DSP4] P > 0.05, F(1,5) = 0.063. Tukey post hoc test used for all ANOVAs: *P < 0.05, **P < 0.01, ****P < 0.0001. See Supplementary Table 1.