Basic research on physiology and pathophysiology of the Eustachian tube function

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Aiming at few researches for thr function and pathogenesis of auditory tube dysfunction diseases, we have continued to study the development of a sonotubometer with our study thesis No. 57870102. In the present study, we proceeded to the next step to study gas metabolism and auditory tube function in the middle ear cavity. In general, the auditory tube bulonging to the middle ear cavity has been explained like an organ to enspire the air under the emvironmental pressure into the middle cavity from outside. However, several loads added while measuring CO_2 in the middle ear cavity mad us understand the air not supplied into the middle ear cavity from the auditory tube completely by opening and closing of the auditory tube in association with deglutition movement in the environment under the ordinary pressure, the existence of specific cavernous gas metabilism as a cavernous properity in the middle ear cavity, and the auditory tube haveing a role to expire it into the outside.1) It was u … More nderstood that po_2 values in the middle ear cavity in normal adults were about 53 mmhg equivalent to about 1/2 of the atomosphere.2) po_2 in the middle ear cavity showed no changes by opening and closing of the auditory tube in association with wsallowing movement.3) It was shown after fixiation of a sensor in the tympanic bulla in the guinea pigs that hte gas was not flowed into the middle ear cavity even after swallowing movements by covering their head with 100% oxygen but gas exchange via the auditory tube existed in the case of a difference in the atomospheric pressure caused by rise of po_2 in the middle ear cavity after swallowing movements by increasing the oxyten pressure to about 100 mmH_2o.4) PO_2 values showed no changes but the pressure in the middle ear cavity was increased when po_2 was determined in humans while sleeping, which was considered to be caused by CO_2 diffusion. The pressure in the middle earcavity was recovered to the normal pressure when deglutition movements occurred.In conclusion, there is a tendency of normal auditory tube function simply to heighten the gaseous pressure in the middle ear cavity due to closed auditory tube at rest, in which the auditory tube is opened by deglutition movements to expire it into the atomosphere. In other words, a phenomenon to heighten the pressure in the middle ear cavity cannot be grasped owing to opened auditory tube by deglutition movements at awakening but the middle ear cavity has specific gas metabolism by heightened pressure in the middle ear cavity at slooe, etc. so that the auditory tube exists as its discharging tube. Less