Glutamate toxicity induced degeneration of outer hair cells with a temporal increase of nitric oxide production in the guinea pig cochlea.
The aim of this study was to examine the roles of glutamate (GLU) toxicity and involvement of nitric oxide (NO) in the pathogenesis of cochlear degeneration. We examined guinea pig cochleae following chronic exposure to GLU. Trypan blue extrusion and transmission electron microscopy were performed to evaluate degeneration in the organ of Corti. In parallel, nitric oxide synthase (NOS) activity was demonstrated by histochemical staining of NADPH diapholase. GLU treatment caused time-dependent degeneration of outer hair cells (OHCs) in conjunction with a temporal increase of NOS activity in the organ of Corti. This suggests that GLU may be involved in OHC degeneration under toxic conditions, with NO production possibly playing a role in this process.
Sunami
K
K
Department of Otorhinolaryngology, Osaka City University Medical School, 1-5-7 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
Yamane
H
H
Nakagawa
T
T
Takayama
M
M
Konishi
K
K
D000818:Animals; D005260:Female; D018698:Glutamic Acid / Q000633:toxicity*; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008854:Microscopy, Electron; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009410:Nerve Degeneration / Q000139:chemically induced* / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009925:Organ of Corti / Q000187:drug effects* / Q000473:pathology; D000160:Vestibulocochlear Nerve Diseases / Q000139:chemically induced* / Q000473:pathology
D009569:Nitric Oxide; D018698:Glutamic Acid; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase