Reflex control of nasal blood vessels.

The effect of stimulation of vagal afferent fibers on nasal blood vessels was studied in 36 cats. Volume change of the nasal capacitance vessels was measured by plethysmographic balloons inserted into the nose. Electrical stimulation of the vagus nerve produced a vasodilatation of nasal mucosa. Pulmonary stretch receptor stimulation by veratridine alkaloid and progressive lung inflation in open-chest cats also produced a vasodilatation of the nasal mucosa. These reflexes were abolished by sectioning the vagus nerves. These results suggest a reflex arc between the lung and nasal capacitance vessels which arises from pulmonary stretch receptors.