Journal: eLife
Article Title: Descending locus coeruleus noradrenergic signaling to spinal astrocyte subset is required for stress-induced mechanical pain hypersensitivity
doi: 10.7554/eLife.104453
Figure Lengend Snippet: ( A ) Schematic illustration of an experiment to investigate the effects of acute exposure to restraint stress (1 hr) on mechanosensory behavior in mice, using von Frey (vF) filaments. ( B ) Change in paw withdrawal threshold (PWT) measured by vF filaments in wild-type mice after restraint stress ( n = 6 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 vs. no-restraint stress group). ( C ) Expression of GCaMP6s (GC; green) in the LC at 3 weeks after intra-LC injection of AAV-FLEx[GCaMP6s] in Slc6a2-Cre mice. TH immunofluorescence is shown in magenta. Dashed line indicates the location of the implanted optic fiber. Scale bar, 100 μm. ( D, E ) Representative traces and change in the frequency of GCaMP6s signals in LC-NA neurons ( n = 6 mice; Friedman test with post hoc Dunn’s multiple comparisons test; **p < 0.01 vs. the data of ‘Before’). Traces shown at the top, middle, and bottom ( D ) indicate Ca 2+ signals before, during, and after restraint stress, respectively. ( F ) Schematic illustration of the strategy of ablating LC-NA neurons using AAV vectors incorporating DTR (fused with EGFP) injected into the LC in Slc6a2-Cre mice. ( G ) TH immunofluorescence (magenta) and GFP (green) in the LC (left) and NET immunofluorescence (magenta) in the SDH (right) after administration of DTX (10 µg/kg, i.p., two injections 24 hr apart) in control mice (top) and DTR-expressing mice (bottom). Scale bars, 100 μm. ( H ) Effect of ablation of LC-NA neurons on PWT changes after acute restraint stress ( n = 7 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; **p < 0.01 vs. control group). ( I ) Schematic illustration of the strategy of ablating LC →SDH -NA neurons using a retrograde AAV vector incorporating Cre injected into the SDH and an AAV vector incorporating DTR (fused with EGFP) injected into the LC in wild-type mice. ( J ) Representative images of LC →SDH -NA neurons in control or DTR-expressing mice treated with vehicle or DTX administration, respectively. GFP (green) and TH (magenta). Scale bar, 100 μm. ( K ) Effect of ablation of LC →SDH -NA neurons on PWT changes after restraint stress ( n = 11 mice per group; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; ** P <0.01 vs. control group). ( L ) Schematic illustration of the strategy for activating LC →SDH -NA neuronal axons/terminals using an AAV vector incorporating ChrimsonR (fused with tdTomato) injected into the LC in Slc6a2-Cre mice and of an optic cannula implanted in the SDH. ( M ) Representative images of TH (green) and tdTomato (magenta) expression in the LC (top) and NET (green) and tdTomato (magenta) expression in the SDH (bottom) at 3 weeks after intra-LC injection of AAV-FLEx[ChrimsonR-tdTomato] in Slc6a2-Cre mice. Scale bars, 100 μm (top) and 50 μm (bottom). ( N ) PWT before and after optogenetic stimulation (opto-stim.) in LC →SDH -NA axons/terminals (625 nm, 2 mW, 10 Hz, 5 ms pulse duration, 5 s light on, 15 s light off, 10 cycles) (Control, n = 4 mice; ChrimsonR, n = 5 mice; two-way ANOVA with post hoc Bonferroni’s multiple comparisons test; ****p < 0.0001 vs. control group). Data represent mean ± SEM. See also – . Some figure elements were created with BioRender.com . Figure 1—source data 1. Raw numerical values for plots.
Article Snippet: To activate ChrimsonR in LC →SDH -NA axons/terminals, 625 nm LED light (#M625F2; Thorlabs) was delivered through a ferrule patch cable (#M83L01; Thorlabs).
Techniques: Expressing, Injection, Immunofluorescence, Control, Plasmid Preparation