Figure 3.

Rodent C-LTMRs express Na_v1.7, which innervate hind-paw hairy and plantar skin. (A) In situ hybridization of L4 DRG sections showing Na_v1.7 mRNA-positive cell co-localization with TH, a C-LTMR marker. Scale bars = 25 µm. (B) All (100%) TH-positive C-LTMRs expressed Na_v1.7 mRNA (226/226 cells from three mice). (C) Example of genetically labelled C-LTMRs using the TH^CreERT2 mouse line crossed with the Cre-dependent reporter (tdTomato). Scale bar = 50 µm. (D) Co-localization of genetically labelled C-LTMRs and TH antibody-labelled C-LTMR cell bodies in the DRG. TH^CreERT2-positive C-LTMRs are a largely non-overlapping population and minimal co-localization was seen between parvalbumin (PV) (E), IB4 (F), CGRP (G) and NF200 (H). (I) Almost all TH-positive C-LTMRs co-express Na_v1.8 as seen by co-localization of genetically labelled Na_v1.8 afferents (Na_v1.8^CreTdTom) and the TH antibody. D–I scale bar = 100 µm. (J) tdTomato-labelled C-LTMRs forming longitudinal lanceolate endings around hair follicles in hind-paw hairy skin. Scale bar = 25 µm. (K) tdTomato-positive C-LTMR innervating the hair follicles found on the plantar surface (located between the running pads) of mice. Scale bar = 25 µm. (L) TH-positive C-LTMRs do not terminate in the skin as PGP9.5+ epidermal free nerve endings. Scale bar = 50 µm.