Structure of the enteric nervous system in the sheep omasum as revealed by neurofilament protein-like immunoreactivity.

The general structure of the enteric nervous system in the omasum of sheep was investigated by immunohistochemical techniques using antineurofilament protein antibody. The myenteric plexus consisted of polygonal ganglia and interganglionic nerve bundles. The meshwork of the plexus in the oral region was denser than the middle and aboral regions. Intraganglionic laminar endings were present in the myenteric ganglia. The submucosal plexus was divided into sublaminar and intralaminar plexuses. The latter was denser near the free border of the omasal laminae than in the region near the omasal wall. There were no ganglion cells showing neurofilament protein-like immunoreactivity in the submucosal and mucosal layers. Probable mucosal receptors were found in the horny omasal papillae near the reticulo-omasal orifice. The findings demonstrate a complicated structure for the enteric nervous system in the omasum, presumably reflecting its regulatory activities.