[The participation of bulbar "respiratory" and "nonrespiratory" neurons in the development of the expiration reflex].

The patterns of impulse activity of medullar neurons were investigated in nembutal-anaesthetized cats during the expiration reflex elicited by electrical stimulation of the internal branch of superior laryngeal nerve. It was shown that low- and high-threshold superior laryngeal afferents caused excitatory reflex reactions of different complexity in significant number of reticular nonrespiratory neurons. Respiratory neurons exhibited systemic changes of spontaneous activity, but in 22.4 per cent of them reflex responses were recorded. These responses occurred during activation of low-threshold laryngeal afferents. Oligo- and polysynaptic excitatory connections of low-threshold laryngeal afferents are found with inspiratory beta neurons, P-cells and laryngeal motoneurons, but inhibitory ones-with inspiratory gamma neurons. Participation of investigated neurons in the mechanisms of inhibition of inspiration, vocal cords closure and rate of breathing adaptive decrease during expiration reflex is discussed.