Calcium gradients in the fish inner ear sensory epithelium and otolithic membrane visualized by energy filtering transmission electron microscopy (EFTEM)
Calcium gradients in the fish inner ear sensory epithelium and otolithic membrane visualized by energy filtering transmission electron microscopy (EFTEM)
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DOI：
10.1016/j.asr.2003.09.043
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发表时间：
2004-01-01
期刊：
影响因子：
--
通讯作者：
Rahmann, H
中科院分区：
文献类型：
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作者：
Ibsch, M;Anken, RH;Rahmann, H
鱼类内耳耳石的形成是由感觉上皮细胞释放蛋白质前体物质，随后是碳酸钙的无定向和扩散沉淀（这是耳石功能重要重量的主要原因）。然而，钙进入内淋巴的途径仍然不清楚。因此，存在的钙内的慈鲷鱼Oreochromis mossambicus幼体椭圆囊的能量过滤透射电子显微镜（EFTEM）分析。电子光谱成像（ESI）和电子能量损失谱（EELS）显示离散的钙沉淀，这是特别多的近端内淋巴相比，远端内淋巴。在感觉上皮和耳石之间的近端内淋巴中也存在一个递减的近端-远端梯度。更多的钙颗粒覆盖在耳石的外周蛋白质层上。它们在耳石的近端表面特别明显。发现其他钙沉淀物在黄斑连接处积聚。这些结果强烈表明，黄斑上皮的顶端区域参与钙的释放，耳石的钙供应发生在近端内淋巴。(C)2003年空间研委会。由爱思唯尔有限公司出版。保留所有权利。
Inner ear otolith formation in fish is supposed to be performed by the molecular release of proteinacious precursor material from the sensory epithelia, followed by an undirected and diffuse precipitation of calcium carbonate (which is mainly responsible for the functionally important weight of otoliths). The pathway of calcium into the endolymph, however, still remains obscure. Therefore, the presence of calcium within the utricle of larval cichlid fish Oreochromis mossambicus was analyzed by means of energy filtering transmission electron microscopy (EFTEM). Electron spectroscopic imaging (ESI) and electron energy loss spectra (EELS) revealed discrete calcium precipitations, which were especially numerous in the proximal endolymph as compared to the distal endolymph. A decreasing proximo-distal gradient was also present within the proximal endolymph between the sensory epithelium and the otolith. Further calcium particles covered the peripheral proteinacious layer of the otolith. They were especially pronounced at the proximal surface of the otolith. Other calcium precipitates were found to be accumulated at the macular junctions. These results strongly suggest that the apical region of the macular epithelium is involved in the release of calcium and that calcium supply of the otoliths takes place in the proximal endolymph. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.