Abstract
Using 9 toads, the sympathetic nerve trunk was cut near the jugular ganglion. In more than a half of efferent nerve endings on the chemoreceptor cells, morphological changes, which were considered to be signs of degeneration, occurred after the surgery. The most suggestive evidence was that massed vesicles or numerous neurofilaments were present in the nerve endings. Seven days after the excision, many synaptic vesicles in various size were clumped, and a gross distintegration of nerve ending was observed. Mitochondria were swollen and sometimes ruptured. Fourteen days after, morphological changes in the nerve endings were more prominent. Nerve endings were filled with numerous neurofilaments and there were a few synaptic vesicles, but no mitochondria. In some nerve endings, a partial retraction of both pre- and postsynaptic membranes was observed. Occasionally socalled cytolysome was present in the nerve ending.
