The functional subdivisions of the nucleus tractus solitarii of the cat in relation to the carotid sinus nerve reflex.

The field potentials evoked by electrical stimulation of the afferent A delta fibers of the ipsilateral carotid sinus nerve (CSN) were surveyed in all the regions of the nucleus tractus solitarii of the cat (NTS responses). Pressor and inspiratory responses, like the CSN chemoreceptor reflex, are elicited by electrical stimulation of the site of the NTS responses in the rostral regions, the lateral portions of the intermediate regions and the commissure regions. On the other hand, depressor and apneic responses, like the CSN baroreceptor reflex, are elicited by electrical stimulation of the site of the NTS responses in the medial portions of the intermediate regions and the dorsal portions of the commissure regions.