The nasal cycle in swine.

The domestic pig exhibits characteristic fluctuations in nasal mucous membrane congestion and decongestion which meet the stipulated criterion for the existence of a nasal cycle. This phenomenon was documented in 6 of the 11 pigs studied. Also, unilateral sympathectomy acutely affects ipsilateral nasal resistance, but this elevated nasal resistance gradually decreases to preoperative values over several weeks. Finally, a new technique using active anterior rhinomanometry has been developed which can be applied to the study of nasal resistance changes in laboratory animals.