Effect of Iodoacetic Acid Upon Cochlear Potentials and The Mechanism of Cm2 Production

Toshimitsu Kobayashi, Ikuo Ise, Ruediger Thalmann

Research output: Contribution to journalArticlepeer-review


The effect of iodoacetic acid (IAA), a potent inhibitor of glycolysis, upon the cochlear potentials of the guinea pig was studied. And subsequently the mechanism of the second order cochlear microphonics (CM2) production was investigated by introducing IAA into either perilymphatic scala (scala tympani or scala vestibuli) before the initiation of ischemia.
The results obtained can be summarized as follows.
1) Both the endocochlear potential (EP) and the cochlear microphonics (CM) declined drastically following perilymphatic or intraarterial application of IAA. When 5×10-3 M IAA was applied perilymphatically, the EP started to decline at about 2 to 3 minutes after the initiation of perfusion and approached to a minimal value (first turn: 44.1±4.5 (n=8) mV, second turn: 56.0±5.0 (n=8) mV) at about 8 to 10 minutes after the start of perfusion. While the EP and CM were severely suppressed both in the first and second turns, the organ of Corti potential (OCP) recorded in the first turn underwent only minor change during the early stage of intoxication with IAA.
2) The duration of the CM2 was shortened markedly by the pretreatment of scala tympani with 5×10-4M (0.5mM) IAA prior to the induction of ischemia. The same pretreatment in scala vestibuli had little effect upon the duration of the CM2. These findings, togather with the fact that the hair cells bathe in the fluid having good communication with the perilymph in scala tympani, strongly suggest that the CM2 originates in the hair cells of the anoxic cochlea supported by the glycolytic energy production.

Original languageEnglish
Pages (from-to)749-760
Number of pages12
JournalNippon Jibiinkoka Gakkai Kaiho
Issue number7
StatePublished - Jan 1983


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