Identification and characterization of the esophagoglottal closure reflex in a feline model

To identify a suitable animal model and to delineate the neural pathway and target organs of the esophagoglottal closure reflex we studied three species. Study showed the existence of an esophagoglottal closure reflex in cats. The presence of this reflex could not be documented in the opossum. In monkeys, because of the inadequacy of the available recording devices, its presence could not be ascertained. In the feline model, the closure response of the vocal folds to the abrupt generalized and segmental distension of the esophagus was similar to that of the humans. Study findings indicate that among glottal adductor muscles at least interarytenoid and lateral cricoarytenoid muscles are involved as target organs of the esophagoglottal closure reflex. Decerebration did not change the frequency of glottal closure response to esophageal distension, supporting the notion that this reflex is completely under brain stem control. Bilateral cervical vagotomy abolished the glottal closure induced by esophageal distension indicating that this reflex is mediated by the vagus nerve. Upper esophageal sphincter (UES) pressure response to esophageal distension by air was variable, suggesting 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 similarities in the elicitation and mediation of this reflex have been found with that of humans. This model could be used for further physiological studies.