Fig. 2
Properties of Nav1.8ChR2-positive mechanoreceptors in the hindpaw glabrous skin of Nav1.8ChR2 mice. A Schematic diagram illustrate the experimental setting for characterizing Nav1.8ChR2-positive, i.e., light-sensitive, mechanoreceptors in the hindpaw glabrous skin of the ex vivo skin-nerve preparation made from Nav1.8ChR2 mice. AP impulses evoked by mechanical stimulation and light stimulation at the same receptive fields were recorded using the pressure-clamped single-fiber recording technique. B Sample traces show examples of Aβ-, Aδ- and C-fiber mechanoreceptors whose conduction velocities (CV) were determined by electrical stimulation. Arrowhead in each panel indicates electrical stimulation artifact, and the latency between the stimulation artifact and AP impulse was used to calculating CV. C Plots of CV of individual Nav1.8ChR2-positive mechanoreceptors (solid circles) and Nav1.8ChR2-negative mechanoreceptors (open squares). D Sample traces show slowly adapting (SA) impulses evoked by an 80-mN ramp-and-hold stimulation in a Nav1.8ChR2-positive Aβ-fiber mechanoreceptor (top), a Nav1.8ChR2-positive Aδ-fiber mechanoreceptor (middle), and a Nav1.8ChR2-positive C-fiber mechanoreceptors. E Percent of Nav1.8ChR2-positive afferent fibers that are mechanosensitive. Numbers in the bar represent Nav1.8ChR2-positive mechanoreceptors over total Nav1.8ChR2-positive afferent fibers tested. F Percent of mechanoreceptors that are Nav1.8ChR2-positive afferent fibers. Numbers in the bar represent Nav1.8ChR2-positive mechanoreceptors over total mechanoreceptors. G Percent of Nav1.8ChR2-positive mechanoreceptors displaying SA and rapidly adapting (RA) impulses. Numbers in the bar represent numbers of recordings. H Examples of AP impulses evoked by blue LED light (50 mW, 1 s) applied to the mechanosensitive receptive field of an Aβ- (top), an Aδ- (middle), and a C-fiber mechanoreceptor (bottom). I Percent of recordings showing SA or RA for the Nav1.8ChR2-positive Aβ-, Aδ-, and a C-mechanoreceptor. Numbers in the bar represent numbers of recordings. J Frequencies of AP impulses evoked by blue light at 1, 10 and 50 mW in SA Aδ-fiber SA-mechanoreceptors (n = 5), C-fiber SA-mechanoreceptors (n = 15), Aβ-fiber RA-mechanoreceptors (n = 23), and Aδ-fiber RA-mechanoreceptors (n = 13). Data represent individual observations or mean ± SEM