2004 Fiscal Year Final Research Report Summary
Experimental study on the changes and regeneration of the cupula due to ototoxic drugs.
| Project/Area Number |
15591833
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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 | Tokyo Medical University |
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Principal Investigator |
SUZUKI Mamoru Tokyo Medical University, Medicine, Professor, 医学部, 教授 (80116607)
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| Co-Investigator(Kenkyū-buntansha) |
YUKAWA Kumiko Tokyo Medical University, Medicine, Assistant Professor, 医学部, 講師 (00201848)
HAGIWARA Akira Tokyo Medical University, Medicine, Assistant, 医学部, 助手 (60297314)
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| Project Period (FY) |
2003 – 2004
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| Keywords | cupula / semicircular canal / otoconia / positional vertigo / Gentamicin / cupulolithiasis / canalolithiasis / 回転刺激 |
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| Research Abstract |
The effects of the changes in physical property of the semicircular canal cupula were studied Mechanical vibration to the middle ear induced detachment of the utricular otoconia both in bull frogs and mammals. The otoconia moved into semicircular canal lumen. This condition was regarded as a model of canalolithiasis of BPPV. When the otoconia were attached to the cupula surface, this was cupulolithiasis model. Both models suppressed the canal nerve activity induced by sinusoidal rotatory stimulus. This is considered to be a mechanism of decreased caloric response and VOR in BPPV patients. Gentamicin was injected into bullfrogs' inner ear and changes of the cupula were studied. The cupula was shrunken into about half size. However, the viscous nature of the cupula surface was maintained. Decreased cupula volume allows easy deflection upon head change, thus possibly leading to the occurrence of positional vertigo. Decreased cupula volume also allows the endolymph escape through ampullary wall, thus possibly leading to vertigo after canal plugging procedure.
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