Histochemical study of the myenteric plexus following gastric resection on dogs.

Enzyme histochemical methods were used to follow up to changes within the myenteric plexus from 1 week to 7 months following subtotal Billroth I gastric resection in dogs. Different regions of the resected stomach were examined. The changes affected the neurons and the neuropil of the myenteric ganglia, the connecting strands and the nerve bundles and fibers within the muscle layers. The changes in size, from and enzyme activity of some myenteric neurons correspond to those observed during axon regeneration. The 2nd week showed a significant reduction of the nerve cell number in most of the examined regions of the resected stomach. Along with, the amitotic forms of cell division and immature nerve cells became more numerous. The enzyme activity of the latter increased with the time elapsed after resection, 7 months afterwards, the size of the myenteric ganglia in the resected stomach did not differ from those in the control dogs. There were some hypertrophic nerve cells with higher enzyme activity. Some changes presume the formation of new intramural ganglia. The changes in the myenteric neurons were accompanied by reactive changes in the non-neuronal elements. Hyperinnervation was observed in the gastric muscles.