Figure 1.

(A) Segments and regions of an adult mouse colon. The specimen was opened along mesenteric margin with mucosa on the top. The proximal colon had mucosa folds aligned diagonally on each side and each fold ended at the antimesenteric margin. The proximal and transverse colon could be divided by the disappearance of the mucosa folds. There is no clear landmark between the transverse and distal colon. About 1.5 cm caudal the proximal colon could be the transverse colon. The area marked by a dashed line is a hypoganglionic region in the antimesenteric margin located at the aboral end of the proximal colon and oral segment of the transverse colon. (B) Segmental difference: representative photomicrographs of AAV9 transduction in the mouse colon. AAV9-CAG-GFP was retro-orbitally injected at 3.3 x 10¹¹ GC/mouse 3 weeks before. AAV9-labeled the enteric neurons and nerve fibers were abundant in the proximal colon (pC), reduced in the transverse colon (tC) and only a few nerve fibers in the distal colon (dC). Upper row: submucosal plexus (SMP); lower row: myenteric plexus (MP). Scale: 100 μm, same for all panels.