The Enteric Nervous System In The Goat: Regional Morphological Differences And The Organization Of Submucosal And Intramucosal Plexuses

Abstract

Regional differences, submucosal and intramucosal organization of ganglia in the enteric nervous system (ENS) of large mammals are not yet clear. The ENS of eight adult goats was studied by S-100 protein, neurofilament proteins, and substance P immunohistochemistry. Numerical density was used to establish intramucosal ganglia distribution. The outer submucosal plexus (OSP) and inner submucosal plexus (ISP) were differentiated using submucosal vascular arcade landmark. Primary nerve strands emerged beneath OSP ganglia and the latter were coarse textured and their primary nerve strands displayed a definitive orientation relative to circular muscle. The OSP and ISP were subdivided into the plexus submucous extremus and intermediate plexus, respectively based on topography, size, shape, outline and density of ganglia and nerve meshworks, and size of nerve cell bodies. Mucosal plexus contained many ganglia and isolated nerve cell bodies with higher numerical densities in caecum, colon and ileum. Myenteric, OSP, ISP and mucosal plexuses showed a similar pattern of regional differences in the size of ganglia and nerve strands. Larger ganglia and large nerve strands were found in the colon and caecum. They were medium sized in the duodenum, rectum, ileum and distal jejunum and smaller in the proximal and middle jejunum. The present study elaborates on the morphological features to differentiate OSP from ISP and suggests that plexus submucous extremus and intermediate plexus exist in intestine of goat. Regional variations of the sizes of ganglia and nerves, stratification of submucosal and intramucosal ganglia suggest a functional significance in regulating muscle, vascular, immune system and mucosal functions. Tanzania Veterinary Journal Vol. 24 (1) 2007: pp. 1-22