Influence of the superior laryngeal and recurrent nerves on several reflex respiratory responses

Abstract

Respiratory effects determined by mechanical stimulation of several areas on the upper respiratory airways epithelium have been studied in cat.Influences of superior laryngeal and recurrent nerves were also observed.Air flow larynx resistance changes have been recorded by means of glottis in situ and isolated technique.Mechanical stimulation of tracheal epithelium showed a cough response with a larynx resistance decrease.The same response was obtained by electrical stimulation of the central end of the recurrent nerve.Bilateral section of those nerves produced a larynx resistance decrease which brought out the predominance of a constrictor tone in the larynx intrinsic muscles maintained by recurrent efferent fibres.Mechanical stimulation of subglottal epithelium was characterized by apnea followed by cough, glottis closures and again expiratory apnea.Bilateral section of superior laryngeal nerves suppressed the above response, otherwise obtained by electrical stimulation of the central end.Mechanical stimulation of supraglottal epithelium was characterized by glottis closures and occasional coughing.Bilateral section of superior laryngeal nerves did not alter this effect.