EFFECT OF CHANGES IN AIRWAY SURFACE LIQUID ON LARYNGEAL RECEPTORS ANDMUSCLES

The effects of aerosolizing distilled water and isosmolal dextrose in the isolated larynx on the activity of pressure-responsive receptors a nd laryngeal muscles were studied in anesthetized dogs. Following wate r aerosolization, the mean discharge of pressure-responsive laryngeal mechanoreceptors during upper airway breathing and occlusion was 151% and 138% respectively of that present after saline aerosolization. Dur ing delivery of water aerosol, the peak activity of the posterior cric oarytenoid muscle increased to 229 +/- 56% of control; no effects were present on the thyroarytenoid muscle activity. Saline or isosmolal de xtrose aerosols did not have any effect on the activity of either musc le. The reflex increase in posterior cricoarytenoid muscle activity du e to laryngeal negative pressure was enhanced (163%) when the negative pressure challenge was repeated following distilled water aerosol. Th ese results suggest that alteration in laryngeal surface liquid compos ition modifies the response of pressure-responsive laryngeal receptors and thereby the reflex activation of airway patency maintaining muscl es.