Figure 4.

Nav1.7 immunolabeling (IL) of arterioles and associated innervation in normal human palmar glabrous skin biopsies, in alternating sections cut parallel to and through lumen (*) of branched arteriole (A-C) and parallel to arteriole, skimming the interface between tunica media (tm) and tunica adventitia (ta) (D,E). All sections are labeled with Abcam anti-human Nav1.7 antibody (red). Secondary antibodies conjugated to Alexa 488 (green) were used to assess co-labeling for: smooth muscle cells revealed with mouse anti-α−smooth muscle actin antibody (αSMA, A); peptidergic sensory innervation revealed with sheep anti-CGRP antibody (yellow straight arrows, B,D); and noradrenergic sympathetic innervation revealed with sheep anti-NPY antibody (yellow curved arrows, C,E): Nuclei are labeled with DAPI (blue). Left images in each panel show only the red fluorescence, middle images only green, and right images the triple-label combinations. Areas outlined in large white rectangles (A-C) are 2X enlargements of areas in small rectangles. A-E. A. Nav1.7-IL is expressed on endothelial cells of tunica intima (red arrowheads) and smooth muscle cells of tm as confirmed by double-labeling with anti-αSMA. Nav1.7-IL is expressed on innervation (arrows) in ta, near and at the border with tm. B, D. Peptidergic sensory innervation co-expresses Nav1.7-IL and CGRP-IL (yellow straight arrows). Other innervation labeled only with Nav1.7 (red curved arrows) is likely noradrenergic sympathetic innervation that expresses NPY-IL (C,E). C,E. Noradrenergic sympathetic innervation co-expresses Nav1.7-IL and NPY-IL (yellow curved arrows). Other innervation labeled with only Nav1.7 (red straight arrows) is likely peptidergic sensory innervation that expresses CGRP-IL as shown in B and D. Scale bar = 100 μm in A-C, 50 μm in D and E.