Online ISSN : 1883-7301
Print ISSN : 0303-8106
ISSN-L : 0303-8106
Evidence Suggesting Negative EP under Normal Condition
Toshimitsu KobayashiJun Kusakari
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1983 Volume 26 Issue 6 Pages 711-715


The origin of the negative EP (endocochlear potential) is still controversial. Some investigators believe that the negative EP does not exist in normal cochlea, but is produced by hair cells under such conditions as ischemia and ototoxic drugs administration. However, we do not agree with them in this respect of generation mechanism of the negative EP, and think that the negative EP exists under normal condition.
The following data seem to lend a further support to our theory.
1) The maximum negativity of the EP produced by perilymphatic perfusion with ototoxic drugs is not different regardless which one of the perilymphatic spaces (the scala vestibuli or scala tympasi) is perfused.
2) Simultaneous perfusion in the scala tympani with control perilymph does not decrease the negativity of the EP attained by perfusion with the ototoxic drug in the scala vestibuli.
3) The elevation of PO2 in the scala tympani in the ischemic cochlea does not result in the increase of the EP.

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