IDENTIFICATION AND CHARACTERIZATION OF THE ESOPHAGOGLOTTAL CLOSURE REFLEX IN A FELINE MODEL

To identify a suitable animal model and to delineate the neural pathwa y and target organs of the esophagoglottal closure reflex we studied t hree species. Study showed the existence of an esophagoglottal closure reflex in cats. The presence of this reflex could not be documented i n the opossum. In monkeys, because of the inadequacy of the available recording devices, its presence could not be ascertained. In the felin e model, the closure response of the vocal folds to the abrupt general ized and segmental distension of the esophagus was similar to that of the humans. Study findings indicate that among glottal adductor muscle s at least interarytenoid and lateral cricoarytenoid muscles are invol ved as target organs of the esophagoglottal closure reflex. Decerebrat ion did not change the frequency of glottal closure response to esopha geal distension, supporting the notion that this reflex is completely under brain stem control. Bilateral cervical vagotomy abolished the gl ottal closure induced by esophageal distension indicating that this re flex is mediated by the vagus nerve. Upper esophageal sphincter (UES) pressure response to esophageal distension by air was variable, sugges ting that glottal and UES response to esophageal distension, although closely coordinated, are not dependent on one another. In summary, an esophagoglottal closure reflex exists in feline species, and many simi larities in the elicitation and mediation of this reflex have been fou nd with that of humans. This model could be used for further physiolog ical studies.