Salicylate, mefenamate, meclofenamate, and quinine on cochlear potentials.
The perilymphatic spaces of guinea pig cochleae were perfused with artificial perilymph, with and without drug, at a rate of 2.5 microliters/minute for 10 minutes. The compound action potential of the auditory nerve, cochlear microphonics, and the summating potential evoked by 10 kHz tone bursts of varying intensities were recorded from a wire inserted in the basal turn scala vestibuli. The endocochlear potential was recorded from the scala media. Sodium salicylate (1.25 to 10 mmol/L) reduced the magnitude of the compound action potential evoked by low-sound intensities without affecting the compound action potential evoked by high-sound intensities. Sodium salicylate also reduced cochlear microphonics and had no effect on summating potential. Cochlear perfusions of prostaglandin synthesis inhibitors, mefenamate (200 mumol/L), and meclofenamate (200 mumol/L), had no effect on the cochlear potentials. Quinine (10 to 100 mumol/L) reduced the compound action potential input-output function in a parallel fashion rather than selectively affecting the low-intensity compound action potential. Quinine (100 mumol/L) reduced cochlear microphonics and summating potential. Neither quinine (100 mumol/L) nor salicylate (5 mmol/L) affected endocochlear potential. These results suggest that salicylate-induced hearing loss is not caused by either antagonism of the hair cell transmitter or cyclooxygenase inhibition, nor is it caused by the same mechanism that causes quinine-induced hearing loss.
Puel
J L
JL
Kresge Hearing Research Laboratory of the South, Department of Otorhinolaryngology and Biocommunication, Louisiana State University Medical School, New Orleans 70112.
Bobbin
R P
RP
Fallon
M
M
D000085:Acetates / Q000494:pharmacology*; D000625:Aminooxyacetic Acid / Q000494:pharmacology*; D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D003051:Cochlea / Q000187:drug effects*; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D006168:Guinea Pigs; D008469:Meclofenamic Acid / Q000494:pharmacology*; D008528:Mefenamic Acid / Q000494:pharmacology*; D011803:Quinine / Q000494:pharmacology*; D012459:Salicylates / Q000494:pharmacology*; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
D000085:Acetates; D012459:Salicylates; D062367:ortho-Aminobenzoates; D000625:Aminooxyacetic Acid; D008528:Mefenamic Acid; D008469:Meclofenamic Acid; D011803:Quinine; D001241:Aspirin