For the etiological study of clinical high tone loss it is necessary to make clear the relationship between cochlear asphyxia and cochlear function, and there have been reports on the effects of oxygen lack on the cochlea. In the present experiments, cochlear microphonics were recorded during normal respiration and asphyxia. The recovery state of cochlear function after re-respiration was observed. Results were as follows. 1) C.M. was recorded by the differential electrode method in the first and third cochlear turn of living guinea pigs and the effects of two minutes asphyxia on the both turns were compared. 2) Input-output curve pattern was used to compare the
asphyxia and re-respiration effect on each cochlear turns. 3) In the input-output curve, C.M. of the first cochlear turn shows ""S"" shape course and the third turn shows ""C""
shape. During the asphyxia, decline of C.M. appeared more prominently in the first turn than the third turn ; these responses may indicate that the first turn is more vulnerable than the other turn. 4) After re-respiration, recovery of the C.M.-I was faster than that of C.M.-III. C.M.-I.
revealed marked overshoot and bounce, whereas very slight overshoot and bounce were observed in the C.M.-III. This results suggest that the first turn receive more
O2 supply than the other turn. 5) Chronic irreversible disorders were not observed after two minutes asphyxia on both cochlear turns. 6) These and other evidences suggest that the anaerobic metabolism can be activated in the third cochlear turn. The etiology of the clinical high tone loss could be better explained by the above experimental results.
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