Fig. 4

Aδ-LTMRs develop longitudinal-lanceolate endings (LLEs) after elaboration/branching in the first postnatal week. A-D Representative images of sparsely labeled Aδ-LTMR receptive fields in mouse back skin. Aδ-LTMR axons are present in the skin at P0 (A, two distinct adjacent RFs shown). Follicle-innervating LLEs first appear by P3 (B); more follicle-innervating endings are present in P6 animals (C), and by P14 nearly all terminal branches end in LLEs (D). Arrowheads – Follicle-innervating LLEs. Scale bar – 100 μm. E Quantification of the number of terminal branches per receptive field (grey) and the number of terminal LLEs per receptive field (red). Points represent individual receptive fields. Bars represent mean ± s.e.m. Total number of receptive fields quantified and (number of animals): P0/1: 61(4), P3: 35(3), P6: 40(3), P14: 68(3) Total branches: ANOVA P ≤ 0.001, LLEs: ANOVA P ≤ 0.001, Total branches vs LLEs: P0/1 Wilcoxon Rank Sum Test P ≤ 0.001, P3 Wilcoxon Rank Sum Test P ≤ 0.001, P6 Wilcoxon Rank Sum Test P ≤ 0.001, P14 Wilcoxon Rank Sum Test P ≥ 0.05