The role of vasopressin to the formation of endolymphatic hydrops

近年来，许多证据支持加压素（VP）在梅尼埃病内淋巴积水的形成中可能起重要作用。本研究的目的是探讨VP在内淋巴积水中的作用。在这项研究中，我们做了两个实验。首先，我们研究了VP的长期给药是否会诱导内淋巴积水。其次，我们研究了血管加压素受体（V2受体）和V2特异性水通道（水通道蛋白2，AQP 2）的表达模式。(1)豚鼠分别以0.2U/kg/min、0.4U/kg/min、1U/kg/min剂量灌胃VP，连续7天。以耳蜗蜗轴中段中阶面积增加率定量评价积水程度。0.4和1U/kg/min组的中阶面积较对照组显著增加。我们证实高浓度VP可引起豚鼠内淋巴积水。(2)本实验采用大鼠耳蜗和内淋巴囊为材料，用RT-PCR方法检测V2受体和AQP 2 mRNA的表达。采用V2受体和AQP 2的特异性引物进行RT-PCR。PCR产物经琼脂糖凝胶电泳后测序。AQP 2和V2受体在大鼠耳蜗和内淋巴囊均有表达。这些结果表明，加压素在内耳水调节中起重要作用，这些实验的所有数据支持VP与梅尼埃病的内淋巴积水密切相关

Recently, many lines of evidence have supported the possibilities that vasopressin (VP) has important role in the formation of endolymphatic hydrops in Meniere's disease. The aim of this study is to investigate the role of VP about endolymphatic hydrops. In this study, we examined two experiments. First, we examined whether or not the chronic administration of VP induce endolymphatic hydrops. Second, we investigated the expression pattern of vasopressin receptor (V2 receptor) and V2 specific water channel (aquaporin 2, AQP2).(1) VP was administered to the guinea pigs at the rats of 0.2U/kg/min, 0.4U/kg/min, 1U/kg/min fo 7days. The degree of hydrops was quatitatively assessed by increase ratio of the scala media area in the mid-modiolar sections of the cochlea. Scala media area of 0.4 and 1U/kg/min group was significantly increased compared with control group. We confirmed the high level of VP induce endolymphatic hydrops in the guinea pig.(2) We investigated the expression of V2 receptor and AQP2 mRNA via RT-PCR.The rat cochlea and endolymphatic sac were used. RT-PCR was done by specific primers for V2 receptor and AQP2. PCR products were electrophorased by agarose gel and sequenced. AQP2 and V2 receptor were both expressed in the rat cochlea and endolymphatic sac. These results indicate that vasopressin has important role for water regulation in the inner ear.In conclusion, all data from these experiments support that VP is closely linked to endolymphatic hydrops in Meniere's disease