An ultrastructural study of the non-neuronal cells in the cardiac ganglia of the monkey (Macaca fascicularis) following unilateral vagotomy.

Non-neuronal cells in the intracardiac ganglia of the monkey (Macaca fascicularis) showed rapid responses to neuronal damage following unilateral vagotomy. Most of the satellite cells appeared normal at one day after operation. However, from three to seven days after operation they were transformed into phagocytic cells, thereby engulfing the transneuronally affected dendrites of the neurons. By seven days after operation, most of the affected dendrites from the neuronal soma were engulfed by the satellite cells. Few macrophages were seen amongst the neurons of the intracardiac ganglia at one day. In monkeys at three to seven days after operation there was a massive infiltration of macrophages into the vicinity of the affected neurons. Several of these macrophages were filled with numerous phagosomes containing partially digested debris. Macrophages also accumulated perivascularly and some intravascular monocytes lay in conformations suggesting that they were undergoing diapedesis. Therefore, perivascular macrophages are probably derived from the circulating monocytes, though the possibility of them being transformed fibroblasts should not be excluded. Schwann cells appeared to be the main scavengers in removing the degenerating myelinated and unmyelinated axons in the intracardiac ganglia after unilateral vagotomy.