TRPV1 and peripheral nerve injury: ChR2 expression in DRGs is ubiquitous among all sensory subtypes (Supplementary Figures 1A, B), however, previous studies reported CCL21 expression specifically in small diameter TRPV1+ nociceptors after peripheral nerve injury (13, 34), so we hypothesized that this CCL21 increase after optogenetic stimulation could be specific of this neuronal subtype.