| Co-Investigator(Kenkyū-buntansha) |
TOOYAMA Ikuo Shiga University of Medical Science, Faculty of Medicine, Professor, 医学部, 教授 (20207533)
TAKEDA Taizou Kochi University, Faculty of Medicine, Professor, 医学部, 教授 (50115763)
鈴木 幹男 国立大学法人滋賀医科大学, 医学部, 講師 (00226557)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2004: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
Meniere's disease is a disorder of unknown aetiology. Symptoms originate in the labyrinth and typically present as a triad of fluctuating deafness, tinnitus and episodes of vertigo. Frequently, endolymphatic hydrops, defined as a distension of the endolymphatic system, is a major pathological finding in Meniere's disease. While the cause of endolymphatic hydrops is not known, it is thought to be due to either a decreased absorptive activity of the endolymphatic sac, or to an increased production of endolymph. To differentiate between these possibilities, however, it is necessary to elucidate the mechanism of fluid regulation in the inner ear. Evidence suggests that the anti-diuretic hormone, vasopressin, may participate in the regulation of inner ear pressure. C-type natriuretic peptide (CNP) and its receptor-ANP-B receptor-, VIP, and its receptor, may also function in the regulation of inner ear. In addition, we obtained novel data showing that not just aquapolin-1(AQP1) mRNA but also AQP1 protein is expressed in the stria vascularis. And we find aquapolin-2(AQP2) regulated by vasopressin in the rat inner ear. These findings suggested that AQP1 and AQP2 play an important role in the regulation system of inner ear fluid. In fact, vasopressin-2 antagonist reduce endolymphatic hydrops in the guinea pigs. As we mentioned first, the cause of endolymphaitic hydrops is not clear, however, to investigate these neuro-peptides will lead us to know the etiology of Meniere's disease.
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