Expiration-related neurons in the region of the retrofacial nucleus: vagal and laryngeal inhibitory influences.

The influences of vagal and laryngeal afferent inputs on expiration-related neurons of Bötzinger complex were studied in anesthetized, paralyzed and artificially ventilated cats. Unilateral electrical stimulation (single shocks or short trains of stimuli at 200 Hz) applied to the cervical vagus nerve or to the superior laryngeal nerve induced inhibitory effects on the activity of these neurons. During apnoea due to hyperventilatory hypocapnia, expiration-related units displayed a low level of tonic activity which was rhythmically inhibited by pump-induced lung inflations. The functional significance of these findings is briefly discussed.