Figure 9.

Localization of ArPPLN2h immunoreactivity in the digestive system of A. rubens. (a) Transverse section of the central disk showing immunostaining in the peristomial membrane, the esophagus and the cardiac stomach. The intensely stained circumoral nerve ring can also be seen here. (b) High magnification transverse section of the esophagus showing immunostained cells and processes in the coelomic lining (arrowheads) and dense immunostaining in the basiepithelial plexus beneath the lumenal epithelial lining of the esophagus. (c) Immunostaining in the cardiac stomach and in the nodule that links the cardiac stomach to extrinsic retractor strands; a high‐magnification image of the boxed area is shown in (d). (d) Immunostained processes can be seen in the basiepithelial plexus beneath the coelomic lining of the nodule (arrowhead) and in the core of the nodule (asterisk). (e) High magnification image of a cardiac stomach showing immunostained cells in the mucosa (arrowhead) and immunostained processes in the basiepithelial nerve plexus beneath the mucosa and in the visceral nerve plexus beneath the coelomic epithelium. (f) High magnification image of the pyloric stomach showing immunostained cells in the mucosa (arrowheads) and immunostained processes in the basiepithelial nerve plexus (black arrow). (g) Immunostaining in a horizontal section of a pyloric duct and pyloric caecum. (h) High magnification image of a pyloric caecum showing immunostaining in mucosal cell bodies (arrowhead), in the basiepithelial nerve plexus (black arrow) and in the visceral nerve plexus (white arrow). BNP, basiepithelial nerve plexus; CE, coelomic epithelium; CONR, circumoral nerve ring; CS, cardiac stomach; CT, collagenous tissue; Es, esophagus; Lu, lumen; Mu, mucosa; No, nodule; PC, pyloric caeca; PD, pyloric duct; PM, peristomial membrane; VNP, visceral nerve plexus. Scale bars: 200 μm in (a); 20 μm in (b), (d), (e), (f), (h); 100 μm in (c), (g)