Respiratory resistances (Rrs) through nose and mouth in response to inhalation of iso-vareric acid were recorded by means of forced pressure and flow oscillations (3Hz) superimposed on spontaneous breathing. Subjects without nasal diseases and olfactory disturbances, and laryngectomized patients were obliged to breathe at a constant pattern, and not to stop breathing during recording of Rrs.
1) Inspite of whether the nasal membrane except for the olfactory region was local-anesthetized or not, Rrs through nose and mouth were significantly increased at 1% level in response to nasal inhalation of the odor, which probably stimulated both olfactory and trigeminal nerves.
2) The increase of Rrs through nose in response to the nasal inhalation did not significantly differ from that through mouth in response to the same stimulation at 5% level.
3) The effect of oral inhalation of the odor on Rrs through mouth was a little if present.
4) In laryngectomized, Rrs below the stoma were significantly increased in response to the odorant stimulation through nose at 5% level.
These results suggest that the increase of Rrs through nose seems to be attributed mainly to the increase of Rrs below mouth, especially below trachea and that the recordings of Rrs in response to olfactory stimulation is useful in objective olfactometry. And olfacto-pulmonary reflex is discussed in this paper.
