Figure 5. Ablation of CeAmy projections to the LC did not affect SIA in uninjured mice, but ablation of CeAmy projections to the LC on the side of sciatic nerve constriction decreased the mechanical allodynia and recovered SIA.

Panel A: SIA in uninjured mice, remains unaffected by ablation of the left or the right CeAmy projections to the LC. Two-Way ANOVA, non-significant for interaction (stress × ablation side), P > 0.05. Panel B: Mice with ablation of CeAmy projections to the LC ipsilateral to the nerve cuff developed mechanical allodynia, but their thresholds increased by postsurgical day 15, Two-Way Repeated Measures ANOVA, ** - significant for interaction (ablation side × subjects), F_3,24 = 4.1, P < 0.01. Panel C: SIA was restored in nerve-cuffed mice after ablation of the CeAmy projections to the LC ipsilateral to the nerve cuff, Two-Way ANOVA, * - significant for interaction (stress × side), F_{1, 24} = 6.5, P < 0.05. Panels D to F show the injection of rAAV-CAG-eGFP-F2A-Cre (D) into the medial dendritic peri-LC zone (E and F). Panels G to I show the retrograde labeling of the CeAmy (G), PVN (H) and LH, (I) all of which are brain areas that unilaterally project to LC. Abbreviations: 3V – third ventricle, BLA - basolateral amygdala, CeAmy – central amygdala, FS – forced swim, GFP – green fluorescent protein, LH – lateral hypothalamus, LC – locus ceruleus, NET – norepinephrine extracellular transporter, ot – optic tract, PVN – paraventricular nucleus, Peri – peri-locus ceruleus zone. Scale bar = 100 μm in D to F and scale bar = 200 μm in G to I.