Laryngeal regulation of airway resistance. II. Pulmonary receptor reflexes.

The response of laryngeal airway resistance to pulmonary receptor stimulation was studied in 20 mongrel dogs anesthetized with alpha-chloralose (80 mg/kg). Stimulation of pulmonary stretch receptors by lung inflation inhibited the phasic variation of laryngeal resistance during respiration and produced a sustained reduction of laryngeal resistance, which was related to lung inflation pressure. Stimulation of pulmonary J-receptors with capsaicin produced apnea and a large increase in laryngea resistance. Capsaicin produced this reflex when injected into the pulmonary circulation but not when injected into the systemic circulation. Irritant receptor stimulation with histamine hydrochloride produced tachypnea and a reduction in inspiratory laryngeal resistance. Pulmonary receptor reflexes were abolished by dividing the vagus nerves distal to the origin of the recurrent laryngeal nerves. Laryngeal reflexes may be important in the regulation of respiration and the production of physiologic and pathologic alterations in pumonary function.