Vagal primary afferent terminals in the dorsal motor nucleus of the rat: are they making monosynaptic contacts on preganglionic efferent neurons?

After horseradish peroxidase (HRP) application to the cut cervical vagus nerve in rats, labelled primary afferent terminals could be demonstrated in the dorsal motor nucleus at the ultrastructural level by a combined glucose oxidase-silver-gold intensification technique. Some labelled boutons contacted labelled dendrites of preganglionic neurons. Thus, the occurrence of a few monosynaptic primary afferent-preganglionic efferent contacts in the dorsal motor nucleus could be demonstrated.