Figure 7.

GFP-ir nerve fibers in the colonic mucosa: relationship to CGRP-ir and TRPV1-ir. A and B, Relationship of GFP-ir (green) and CGRP-ir (red). DAPI labeling is shown in gray. Images are projections of 10 slices 1 μm apart. A, Colocalization of GFP- and CGRP-ir is indicated by orange hue in fibers (arrowheads); however in some cases in the merged pseudocolored image, intense labeling in one channel masks the labeling in the other channel creating the appearance of non-overlapping GFP-ir and CGRP-ir fibers (arrows). The single labeled insets are shown at doubled magnification to better illustrate fibers manifesting low intensity of labeling. Asterisk indicates the crypt region of a mucosal fold. B, A solitary nerve fiber immunoreactive for both GFP and CGRP in an oblique section through the mucosa. C and D, Relationship of GFP-ir (green) and TRPV1-ir (red). DAPI labeling is shown in gray. C, A nerve fiber immunoreactive for both GFP and TRPV1 in the crypt region of the mucosa (crypts indicated by #). TRPV1-positive/GFP-negative fibers are also present. D, Nerve fibers near the mucosal surface (double-ended arrow indicates the location of the epithelium at the mucosal surface). The alternating appearance of GFP- and TRPV1-ir suggests that two separate fibers are intertwined (arrow). Colocalization may exist in the fine-caliber fiber (arrowhead). Scale bars: A, 20 μm relative to A and 10 μm relative to insets; B and C, 20 μm; D, 10 μm.