The distribution of the cat's carotid sinus nerve afferent and efferent cell bodies using the horseradish peroxidase technique.

The location of both afferent and efferent carotid sinus nerve (CSN) cell bodies in the cat has been determined using the horseradish peroxidase (HRP) technique. Following a limited exposure of the central cut end of the CSN to HRP, labeled sensory ganglion cells were found in both the petrosal and superior ganglia of the IXth cranial nerve. An average of 387 in the former and 16 cells in the latter ganglion were labeled. Retrogradely labeled neurons were found only within the ipsilateral medulla. These cells were both round and spindle shaped and had an average somal diameter of 19 micrometer. The number of these CSN efferent cell bodies ranged from 1 to a maximum of 20 in a given animal. They were found in both the nucleus parvocellularis and the retrofacial nucleus. In 8 cases axonal labeling was observed. Axons generally projected dorsomedially from the ventrolateral medulla.