VERY LOW CALCIUM CONTENT OF COCHLEAR ENDOLYMPH, AN EXTRACELLULAR FLUID
VERY LOW CALCIUM CONTENT OF COCHLEAR ENDOLYMPH, AN EXTRACELLULAR FLUID
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DOI：
10.1038/273377a0
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发表时间：
1978-01-01
期刊：
影响因子：
64.8
通讯作者：
WARREN, RL
中科院分区：
文献类型：
--
作者：
BOSHER, SK;WARREN, RL
离子钙在许多膜功能中是重要的，并且它参与耳蜗转导过程的可能性得到了现有证据的支持。在亚哺乳动物物种的类似侧线器官中，毛细胞的机械敏感性与其专门受体极处的外部钙浓度直接相关2。也有证据表明，与单价阳离子效应的相互作用2，3。在哺乳动物中，耳蜗导管充满了内淋巴，其不寻常的构成（在大鼠直流电位+88 mV，K +148 mM，Na+0.84 mM）似乎完全由主动转运机制4维持，并且通常被认为是正常转导所必需的。我们在此报告，在大鼠耳蜗内淋巴钙浓度为3×10− 5 M时，几乎完全以非复合状态存在。这基本上低于通常的细胞外浓度，并且必须影响受体极膜的功能，并且可能很好地影响钙在耳蜗中的转导过程中的作用。我们测得的总镁浓度为1×10−5M。
IONIC calcium is important in many membrane functions and the possibility of it being involved in the cochlear transduction processes is supported by the scanty evidence available1. In the analogous lateral line organ of submammalian species, the mechanosensitivity of the hair cells is related directly to the external calcium concentration at their specialised receptor poles2. There is also evidence of interaction with monovalent cation effects2,3. In mammals, the cochlear duct is filled with endolymph, the unusual constitution of which (in the rat d.c. potential + 88 mV, K+148 mM, Na+0.84 mM) is seemingly maintained entirely by active transport mechanisms4and is generally conceded to be necessary for normal transduction. We report here that the cochlear endolymph calcium occurs almost entirely in the non-complexed state at a concentration of 3×10−5M in the rat. This is substantially below the usual extracellular concentration, and must influence the function of the receptor pole membranes and might well affect the role of calcium in the transduction process in the cochlea. The total magnesium concentration we measured was 1×10−5M.