抄録
Wistar rats were intraperitoneally injected with 0.02 units/g of AVP (Pitressin; Arg-vasopressin. Daiichi-Sankyo, Japan) in all the experiments in this study. ABR thresholds gradually increased significantly up to 60 min after the injection. When dehydration load pretreatment for 24h was added, ABR thresholds rapidly increased significantly up to 10 min after the injection. However, the morphological endolymphatic hydrops in the cochlea was not detected under light microscopy. On the other hand, the enlargement of an area lacking intracellular organelles in the intermediate cells in the stria vascularis or a so called “vacuole” was detected under transmission electron microscopy after the AVP injection. When the dehydration load pretreatment for 24h was added, the vacuole area increased with AVP injection. However, when a V2R antagonist (OPC-31260, donated by Otsuka Pharmaceutical) was administered before AVP, vacuole formation was suppressed significantly. Conversely, vacuole formation was not suppressed when a V1aR antagonist (OPC-21268, donated by Otsuka Pharmaceutical) was administered before AVP injection. As a clinical application based on above mentioned basic studies, we conducted hydration therapy for Meniere's disease. In the hydration therapy, basically the patients drank 35 ml/kg/day of water daily in addition to the normal daily beverages and foods for 2 years. Medication of 21 g was given whenever a vertiginous spell or hearing loss or aural fullness reoccurred. The outcomes were determined according to the criteria of the AAO-HNS 1995 guidelines. In the hydration therapy group, the definitive spells were controlled in 93% of the patients. The hearing in the hydration therapy group was improved significantly in comparison with the conventional therapy group.
