2000 Fiscal Year Final Research Report Summary
The investigation of the hypothesis, glutamate-Ca-nitric oxide (NO), in the inner ear disturbance
| Project/Area Number |
10671607
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | OSAKA CITY UNIVERSITY |
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Principal Investigator |
YAMANE Hideo Osaka City University, Medicine, Professor, 医学部, 教授 (60145787)
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| Co-Investigator(Kenkyū-buntansha) |
KUBO Takshi Osaka City University, Medicine, Assistant Professor, 医学部, 講師 (60271194)
IGUICHI Hiroyoshi Osaka City University, Medicine, Assistant Professor, 医学部, 講師 (70271195)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Nitric oxide / Glutamate / Inner ear / aopotosis / aminoglycoside / シスチン |
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| Research Abstract |
We investigated effect of Nitric oxide (NO) in the inner ear disturbances.
The two concentrations, 0.5 and 0.1 molar concentration (MC) of 1-Hydroxy-2-oxo-3-(3-aminopropyl)-3-isopropyl-1 -triazene (NOC-5) which is NO donor was placed on the round window of the guinea pig cochlea and its morphological changes were investigated at 12, 28, 72 h after the treatment. The inner ear hair cell died in the manner of apoptosis.
Glu induced death of cochlear outer hair cells (OHCs). We investigated the effect of cystine supplementation on degeneration of cochlear outer hair cells (OHCs). caused by long-term exposure to Glu.. Supplementation of cystine significantly decreased the number of dying OHCs..
We examined the cellular location of cytochrome c in streptomycin-damaged vestibular hair cells. suggesting that redistribution of cytochrome c is involved in the pathway of apoptosis in vestibular hair cells induced by aminoglycosides..
We examined guinea pig cochleae following chronic exposure to GLU to evaluate degeneration in the organ of Corti. In parallel, NO synthase (NOS) activity was demonstrated.. GLU treatment caused time-dependent degeneration of OHCs in conjunction with a temporal increase of NOS activity in the organ of Corti..
We used nicotinamide adenine dinucleotide phosphate-diapholase staining to monitor NOS activity during degeneration of guinea pig vestibular epithelia affected by streptomycin. Increased NUS 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 tha NO is involved in the degenerative process of vestibular epithelia caused by aminoglycosides.
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