Reflex effects of upper airway irritation on total lung resistance and blood pressure

Mechanical irritation of the laryngeal mucosa reflexly increased total lung resistance distal to the larynx in cats anesthetized with chloralose and urethan and in decerebrate cats. The afferent limb of the reflex is in the superior laryngeal and the efferent limb in the vagus nerves. Stimulation of the larynx also increased activity in efferent parasympathetic nerve fibers going to the trachea and bronchi. Mechanical irritation of the nasal mucosa did not change total lung resistance. Stimulation of the nares or larynx increased arterial blood pressure conspicuously in decerebrate cats but only slightly in cats anesthetized with chloralose and urethan. The efferent path of the hypertensive response is in the sympathetic nerves, the afferent path for the nasal effect is in the fifth cranial nerves, and the afferent path for the laryngeal effect is in the superior laryngeal nerves.