Superior laryngeal nerve response patterns to chemical stimulation of sheep epiglottis

Responses were recorded from single fibers of the sheep superior laryngeal nerve during stimulation of the epiglottis with 0.5 M KCl, NH4Cl, NaCl and LiCl, distilled water, 0.005 M citric acid, and 0.01 N HCl. Recordings were made from both lambs and ewes. KCl elicited a response from 99% of fibers followed in order of effective stimulation by NH4Cl, HCl, distilled water, citric acid, NaCl and LiCl. Analysis of the variation in response frequency with time demonstrated differences in the response patterns for these stimuli. The pattern of frequency over time is sufficient to discriminate among the salts, between some of the salts and acids, and between some of the salts and water. Therefore the response pattern may be significant in initiating the various reflex activities that occur during chemical stimulation of the larynx.