Nasal exposure to airway irritants triggers a mucociliary defence reflex in the XXXX maxillary sinus.

@entity2951 @entity3265 @entity95 @entity3655 @entity386
The effect on mucociliary (m.c.) activity in the @entity95 maxillary sinus of cigarette smoke and @entity3265 ( @entity3655 ) vapour delivered through a tracheal cannula or as nasal challenges was investigated by a photo-electric technique, and compared with simultaneously induced changes in the respiratory rate. Neither irritant had any effect on m.c. activity in the sinus after tracheo-bronchial exposure. However, the respiration rate was increased by @entity3655 vapour (2.5 ml, diluted 1:1 with room air) and neat cigarette smoke (10 ml) by 76.9% and 24.3% respectively (median values). In contrast, nasal challenges with both irritants increased m.c. activity by 24.1% ( @entity3655 ) and 19.1% (cigarette smoke), and reduced the respiration rate by 31.0% ( @entity3655 ) and 28.4% (cigarette smoke) (median values). @entity3655 vapour sometimes produced an @entity386 proper. Identical results were obtained in laryngectomized @entity95 , indicating that laryngeal afferents were not involved in the responses. Moreover, topical application of the C-fibre stimulant @entity2951 mimicked the effects produced by the airway irritants. It is concluded that nasal exposure to irritants triggers at least two different protective reflexes. One is the increase of m.c. activity in the upper airways involving sensory C-fibres and the other the apneic reflex of Kratschmer.
