The development of the peripheral autonomic nervous system in relation to the gastro-intestinal tract

In this study the development of vagus nerves and the development of sympathetic nerves related to the development of the upper gastro-intestinal tract was studied in the rat from 12.5 days p.c. until birth by means of enzyme histochemical methods applied to sections and toto preparations. A striking time relation between the ingrowth of the vagus nerves as well as the sympathetic nerves and the appearance of acetylcholinesterase (AChE)-positive cells in the wall of the upper gastro-intestinal tract is established. The maturation of the upper enteric ganglion cells is dependent on the presence of a vagal influence. The vagal ingrowth of the stomach starts at about day 12.5 p.c. In AChE toto preparations it is established that the basic distribution pattern as described in the adult rat is complete at day 15 p.c. However, in contrast with the adult state, gastric branches can be traced up to the pylorus and the greater curvature until day 18 p.c. During the 18th day p.c. there is a tremendous increase in the surface area of the stomach. This increase in surface area of the gastric wall and relative decrease in vagal outgrowth leads to the adult configuration of vagal ramifications in relation to the wall of the stomach which can already be observed on the 19th day p.c.