Sympathetic control of nasal erectile tissue.

A model is described to explain the oscillations in sympathetic tone observed in the erectile tissue of the nasal mucosa. The sympathetic innervation of the nose exhibits two types of activity, (A) oscillations in tone in phase with respiration, (B) reciprocal changes in sympathetic tone which are associated with a nasal cycle of airflow between the two nasal passages over a period of 1-4 hr. Type (A) oscillations may be caused by a loose coupling between groups of nasal vasomotor neurones and respiratory neurones. Type (B) reciprocal changes in sympathetic tone may be regulated by a "central rhythm" of nervous activity and by sensory input from the nasal mucosa.