Fig. 2: In vivo optical recording of mechanically (brush or von Frey)-induced neuronal activity in intact DRG neurons.

a Optical voltage recordings of primary sensory neurons in response to the indicated stimuli in naïve, CFA, or SN-CCI animals. Purple bars indicate the timing of the stimulus application. Inset, images of DRG cell bodies (white dotted lines) expressing ASAP4.4-Kv. Yellow lines indicate 1.1 kHz line scan regions where ASAP4.4-Kv fluorescent signals were acquired. Red arrow marks one of action potentials and red box indicates action potential burst. Scale bar: 5 μm. b In vivo intact DRG Ca²⁺ imaging from naïve or CFA-treated Pirt-GCaMP3 mice. (left) Averaged images before brush stimulus was applied. (right) Averaged images after brush stimulus was applied. White arrowheads indicate spontaneously activated neurons without application of stimulus. Yellow arrowheads indicate DRG neurons activated by brush stimulus. Scale bar: 100 μm. c GCaMP3 Ca²⁺ transients from individual DRG neurons (grey traces) and averaged Ca²⁺ transients (black or orange) from naive or CFA animals. d Mean area under the curve (AUC) of ASAP4.4-Kv z-score signals and GCaMP3 Ca²⁺ transients in stimulated L5 DRG neurons. Brush (GCaMP3): violin plot with median (solid line) and quartiles (dashed lines); number of cells = 21 and 19 for naïve and CFA groups, respectively, from three biologically independent mice per group; two-tailed Mann-Whitney U-test. Brush and 0.4 g von Frey (ASAP4.4-Kv): each dot represents an individual recorded neuron (number of cells = 4 from three biologically independent mice per group; Kruskal-Wallis test with Dunn’s post-hoc test). 2 g von Frey (ASAP4.4-Kv): each dot represents an individual recorded neuron (number of cells = 5 from three biologically independent mice per group; Kruskal-Wallis test with Dunn’s post-hoc test). All data are presented as mean values ± SEM.