Fig. 7: In vivo optical recording of intact DRG neurons in response to application of chemical stimuli (high potassium or capsaicin).

Representative traces of optical voltage recordings of primary sensory neurons before (baseline) and after topical application of KCl (50 mΜ) or capsaicin (10 μM) to L5 DRG from naïve (a), CFA (b), or SN-CCI (c) animals. Representative line scan images in c are shown under the traces. d Mean area under the curve (AUC) of ASAP4.4-Kv z-score signals (each dot represents an individual recorded neuron; Naïve: number of cells = 9 for baseline, KCl, and capsaicin conditions. CFA: number of cells = 13, 11, and 10 for baseline, KCl, and capsaicin conditions, respectively. SN-CCI: number of cells = 12, 1,0 and 9 for baseline, KCl, and capsaicin conditions, respectively. Data were obtained from three biologically independent mice per group; Kruskal-Wallis test with Dunn’s post-hoc test). e AUC of GCaMP3 Ca²⁺ transients in L5 DRG neurons in response to indicated chemical stimuli (violin plot with median (solid line) and quartiles (dashed lines); KCl: number of cells = 105 and 129 for naïve and CFA groups, respectively. Capsaicin: number of cells = 166 per group. Data were obtained from three biologically independent mice per group; two-tailed Mann-Whitney U-test). In vivo intact DRG Ca²⁺ imaging from naïve or CFA-treated Pirt-GCaMP3 mice. (left) Averaged images before application of indicated chemical stimuli. (middle) Averaged images after application of indicated chemical stimuli. Neurons activated by KCl or capsaicin are highlighted by bright fluorescence signals. Scale bar: 100 μm. (right) Ca²⁺ transients (gray traces) from DRG neurons in response to topical application of KCl (f) or capsaicin (g) onto DRG neurons from naïve or CFA-treated Pirt-GCaMP3 mice. Traces of averaged Ca²⁺ transients from each group are shown in black or orange. All data are presented as mean values ± SEM.