Sodium- and potassium-activated ATPase in the mammalian vestibular system
Sodium- and potassium-activated ATPase in the mammalian vestibular system
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DOI：
10.1016/s0378-5955(02)00352-0
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发表时间：
2002-09-01
期刊：
影响因子：
2.8
通讯作者：
Kerr, TP
中科院分区：
文献类型：
--
作者：
Pitovski, DZ;Kerr, TP
用放射自显影和细胞化学方法测定了Na，K-ATP酶在哺乳动物前庭系统中的细胞分布。用[H-3]哇巴因孵育的前庭组织的光镜观察表明，在半规管壶腹的暗细胞上皮（DC）内有高密度的哇巴因结合位点，在较小程度上，在椭圆囊斑的DC内也有高密度的结合位点。在壶腹和黄斑感觉上皮（SE）下方的结缔组织中发现了中等数量的结合位点。少数结合位点分布在SE的深部，包括壶腹和黄斑。后者的结合位点似乎与神经末梢和受体细胞有关。在超微结构水平上，前庭暗细胞表现出广泛的基底外侧膜内折，这是参与跨上皮离子转运的细胞的形态学标志。细胞化学反应产物是K+依赖性的。哇巴因是可降解的，并且仅限于基底外侧膜延伸，在管腔膜上几乎没有产物。胞囊暗细胞膜内折叠的程度不如壶腹暗细胞明显，细胞化学反应的强度似乎与膜内折叠的程度相关。这些结果支持了前庭暗细胞在内淋巴产生中起作用的广泛持有的假设。他们还建议前庭感觉上皮可能是一个网站的离子交换。(C)2002 Elsevier Science B. V.保留所有权利。
Autoradiographic and cytochemical procedures were employed to determine the cellular distribution of the Na,K-ATPase enzyme in the mammalian vestibular system, A light-microscope survey of vestibular tissues incubated with [H-3]ouabain shows high densities of ouabain binding sites within the dark cell epithelium (DC) of the ampullae of the semi-circular canals, and to a lesser extent, the DC of the utricular macula. A moderate number of binding sites was found in nerve fibers penetrating the connective tissue beneath the sensory epithelium (SE) of the ampullae and the maculae. A small number of binding sites is distributed in the deep portion of the SE, both in the ampullae and in the maculae. These latter binding sites seem to be associated with nerve terminals and receptor cells. At the ultrastructural level, the vestibular dark cells exhibit extensive basolateral membrane infolding, a morphological hallmark of cells engaged in trans-epithelial ion transport. The cytochemical reaction product is K+-dependent. ouabain inhibitable, and is restricted to the basolateral membrane extensions, with little of no product on the luminal membrane. The extent of membrane infolding in dark cells of the utricle is less pronounced than that of the ampullar dark cells and the intensity of the cytochemical reaction appears to correlate with the extent of membrane infolding. The results support the widely held hypothesis that the vestibular dark cells play a role in endolymph production. They also suggest that the vestibular sensory epithelia may be a site of ion exchange. (C) 2002 Elsevier Science B.V. All rights reserved.