Structure of the myenteric plexus in the sphincters of cat gastro-intestinal tract. IV. Light-microscopic characteristics.

The structure of the myenteric plexus in the lower esophageal, pyloric and ileo-caecal sphincters of cats is studied in semi-thin sections through impregnation and demonstration of cholinesterase. The plexus ganglia are shown to be well formed structures, with varied sizes and shapes, in the collagen between the muscle layers of the sphincters. Impregnation reveals clearly in them Dogiel's neurones of 1st and 2nd type. The neurones and the nerve bundles of the plexus manifest intensive cholinesterase activity. The morphological data obtained are discussed in view of some functional specificities of the sphincter regions.