Abstract
Using the horseradish peroxidase (HRP) technique, the central origin of efferent fibers in the carotid sinus nerve (CSN) was examined in the cat.
To avoid false labeling due to uptake from the nerve endings in the adjacent tissues of the CSN, the critical amount of HRP was sought, which was estimated at 0.5 mg. Applying 0.5 mg of HRP to the central cut end of the CSN, many labeled cells were found in the petrosal ganglion, but no labeled cells were found in the central structure. The findings of this study indicate that the origin of the most efferent fibers in the CSN is not in the central structure, but that it may be in the extracranial part of the glossopharyngeal nerve.
