REFLEXOGENIC AREAS FOR VELOPHARYNGEAL CLOSURE IN RABBITS

Responsive areas for velopharyngeal closure were examined by recording diaphragmatic and superior pharyngeal constrictor activities of anest hetized rabbits. Pressure stimulation was applied with a cotton applic ator to the mucosae of three pharyngeal areas: the anterior (palatal) and posterior walls of the nasopharynx and the posterior wall of the o ropharynx, The intensity and duration of the stimulation were around 9 .0 gf and 0.43 sec, respectively. Velopharyngeal closure was elicited more frequently from the posterior wall of the nasopharynx than the ot her two areas tested. The higher responsiveness of the posterior wall of the nasopharynx for velopharyngeal closure is suggested to be attri buted to higher density and/or lower threshold of pressure receptors i n this area than those in the other two areas tested, Possible physiol ogical implications of the present results are discussed.