| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
In order to evaluate the homeostasis of water in the inner ear, localization of AQP-2,-3,-4,-6,-7,-8,-9 and V2-R in the lateral wall of the cochlea were investigated and water homeostasis of the cochlea was discussed.
Molecular biological and histochemistry studies were performed. Animals used were Wistar rats. In molecular biological study, the expression of AQP-2,-3,-4,-6,-7,-8,-9 and V2-R mRNAs was investigated. In histochemistry study, localization of AQP-2,-3,-4,-6,-7,-8,-9 and V2-R was observed by a Confocal laser microscopy.
AQP-2,-3,-4,-6,-7,-9 and V2-R mRNAs were expressed in the rat cochlea. Histochemistry revealed that Proteins of AQP-2,-3, and V2-R were expressed in the basal cells on the stria vascularis. AQP-6 protein was detected in the all cells of the stria vascularis. On the other hand, AQP-4 was not expressed in the lateral wall of the stria vascularis.
AQP-7,-9 were expressed in the apical site of the marginal cells.
AQP-2,-3 and V2-R is localized in the basal cells, located at the boundary between the perilymphatic system and the endolymphatic system. Since osmolality is generally thought to be higher in the endolymphatic compartment, water might enter into the extracellular space via these water channels. Water in the extracellular space is speculated to enter the marginal cells through Na-K-Cl cotransporter and to flow out through AQP-7 and-9 located in the apical membrane.
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