Figure 8.

Patterns of distribution of TH-IR fibers in the colorectum and the urinary bladder. Confocal immunofluorescence photomicrographs of colorectal (A–D) and urinary bladder (E–H) sections, after incubation with TH antiserum. (A–D) In longitudinal (A, B) as well as coronal (C, D) sections of the colorectum, TH-IR fibers were detected in all layers. Thus, TH-IR fibers could be seen in the muscular layers, in association with the myenteric plexus (arrows in A and C), or in the submucosal layer, either around blood vessels (double arrowheads in B) or in small nerve bundles (double arrows in A, C). A number of TH-IR fibers could also be seen in the colorectal villi, occasionally reaching the basal mucosal cells (arrowheads in A–D). (E–H) In the urinary bladder, thick TH-IR nerve bundles were found penetrating the organ (black arrowhead in E), traveling within the muscular layer (arrows in F, H) or distributed through the lamina propria (white arrowheads in E–H). In the muscular layer, TH-IR nerve profiles appeared sparsely distributed (arrows in F, H). A few of the lamina propria TH-IR fibers were detected in the vicinity of the urothelium (white arrowheads in G). In addition, TH-IR fibers could be observed arranged in thick bundles around blood vessels (asterisk in H, shown at higher magnification in inset) present in the lamina propria (double arrowheads in H). Note the presence of the major pelvic ganglion, strongly immunoreactive for TH (black arrow in E) Scale Bars: 100 µm (B=A; C; E; H); 50 µm (D; F; G; inset in G).