Involvement of nitric oxide in aminoglycoside vestibulotoxicity in guinea pigs.
Involvement of nitric oxide (NO) has been reported in physiological and pathological conditions in the inner ear. Recently, the presence of nitric oxide synthase (NOS) was demonstrated in the vestibular epithelium. In this study we used nicotinamide adenine dinucleotide phosphate-diapholase staining to monitor NOS activity during degeneration of guinea pig vestibular epithelia affected by streptomycin. Increased NOS activity was observed in affected epithelia in a dose- and time-dependent manner and a NOS inhibitor could protect hair cells from apoptosis. Additionally, cycloheximide significantly reduced NOS activity and the occurrence of apoptosis. These findings suggest that NO is involved in the degenerative process of vestibular epithelia caused by aminoglycosides.
Department of Otorhinolaryngology, Yodagawa Christian Hospital, Osaka, Japan.
T
T
Nakagawa
H
H
Yamane
M
M
Takayama
K
K
Sunami
Y
Y
Nakai
D000617:Aminoglycosides / Q000633:toxicity*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000187:drug effects / Q000201:enzymology; D006168:Guinea Pigs; D018069:Hair Cells, Vestibular / Q000187:drug effects / Q000201:enzymology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D013307:Streptomycin / Q000633:toxicity; D013997:Time Factors; D014722:Vestibule, Labyrinth / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D009247:NADH, NADPH Oxidoreductases; D013307:Streptomycin