Effects of bilateral vagotomy on the ultrastructure of the cardiac ganglia in the monkey (Macaca fascicularis).

This study describes the effects of bilateral vagotomy on the ultrastructure of the cardiac ganglia of the monkey (Macaca fascicularis). One to three days after bilateral vagotomy there is widespread glycogen accumulation in the cytoplasm of the principal cardiac neurons. This is associated with distension of the granular endoplasmic reticulum and the loss of ribosomes from the cisternae. Between five and ten days after operation, about 10% of the neuronal profiles show an overall increase in electron density and intense darkening of the dendrites. From twenty one to twenty eight days postoperatively, the majority of the neuronal profiles have pale cytoplasm with reduction in granular endoplasmic reticulum and polyribosomes. The plasma membrane of the neuron is ruffled over the major portion of its surface. The satellite cells, which are reactive throughout the course of the experiments, exhibit a phagocytic capacity at this stage by removing portions of the neuronal cytoplasm. Vacuolation of the neuronal cytoplasm to a variable degree occurs in a small number of profiles between five to twenty eight days. The results suggest that bilateral vagotomy causes a widespread disturbance in the metabolic activity of the cardiac neurons. This is followed by transneuronal degenerative changes that are of a prolonged nature.