THE OSMOTIC RESPONSE OF THE ISOLATED, UNFIXED MOUSE TECTORIAL MEMBRANE TO ISOSMOTIC SOLUTIONS - EFFECT OF NA+, K+, AND CA2+ CONCENTRATION
THE OSMOTIC RESPONSE OF THE ISOLATED, UNFIXED MOUSE TECTORIAL MEMBRANE TO ISOSMOTIC SOLUTIONS - EFFECT OF NA+, K+, AND CA2+ CONCENTRATION
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DOI：
10.1016/0378-5955(95)00089-m
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发表时间：
1995-07-01
期刊：
影响因子：
2.8
通讯作者：
WEISS, TF
中科院分区：
文献类型：
--
作者：
SHAH, DM;FREEMAN, DM;WEISS, TF
测量小鼠离体盖膜 (TM) 的大小、形状和结构的变化，以响应沐浴溶液离子组成的等渗变化。用人工外淋巴 (AP) 替代人工内淋巴 (AE) 导致 TM 厚度小幅（约 1%）收缩。这种取代不仅改变了主要阳离子（从 K+ 变为 Na+），而且还改变了 Ca2+ 浓度（从 20 μmol/l 变为 2 mmol/l）。当主要阳离子从 K+ 变为 Na+ 时，同时保持 Ca2+ 浓度恒定，结果取决于 Ca2+ 浓度：对于 20 μ mol/l Ca2+，有较小的膨胀（大约 1%）；对于较低浓度（< 7 μmol/l）的 Ca2+，膨胀较大（大约 14%）；对于 2 mmol/l Ca2+ 或含有 Ca2+ 螯合剂的溶液，几乎没有响应EGTA。在保持主要阳离子常数的同时添加 Ca2+ 会导致 TM 收缩；除去 Ca2+ 和添加 Ca2+ 螯合剂 EGTA 都会引起肿胀。如果肿胀程度较小，肿胀反应在很大程度上是可逆的。大于几个百分点的响应仅是部分可逆的，并会导致持久的变化。浴中离子成分的变化不仅影响 TM 的厚度，还影响其其他尺寸。增加 TM 厚度的溶液变化往往会引起 TM 表面的径向剪切运动，同时伴随着宽度的小幅减小。观察到长度变化很小。尽管响应是非各向同性的，但厚度的增加与体积的增加高度相关。 TM 的肿胀还伴随着其径向纤维结构的突出度的降低。 小鼠分离 TM 的这些结果在质量上与之前分离小鸡 TM 获得的结果相似（Freeman 等人，1994），但与体外小鼠 TM 获得的结果不同（Kronester-Frei，1979a）。
Changes in the size, shape, and structure of the isolated tectorial membrane (TM) of the mouse were measured in response to isosmotic changes in the ionic composition of the bathing solution. Substitution of artificial perilymph (AP) for artificial endolymph (AE) caused a small(approximate to 1%) shrinkage of the TM's thickness. This substitution alters not only the predominate cation (from K+ to Na+) but also the Ca2+ concentration(from 20 mu mol/l to 2 mmol/l). When the predominate cation was changed from K+ to Na+, while holding Ca2+ concentration constant, results depended on Ca2+ concentration: there was a small(approximate to 1%) swelling for 20 mu mol/l Ca2+, larger (approximate to 14%) swelling for lower (< 7 mu mol/l) concentrations of Ca2+, and little response for 2 mmol/l Ca2+ or for solutions containing the Ca2+ chelator EGTA. Addition of Ca2+ while holding the predominate cation constant caused shrinkage of the TM; both removal of Ca2+ and addition of the Ca2+ chelator EGTA caused swelling. Swelling responses were largely reversible if the magnitude of the swelling was small. Responses greater than a few percent were only partially reversible and caused long-lasting changes.Changes in ionic composition of the bath affected not only the thickness of the TM but also its other dimensions. Solution changes that increase TM thickness tend to cause radial shearing motions of the surfaces of the TM, which are accompanied by small decreases in width. Little change in length was observed. Although the responses were non-isotropic, increases in thickness were highly correlated with increases in volume. Swelling of the TM was also accompanied by a reduction in prominence of its radially oriented fibrillar structure.These results for the isolated TM of the mouse are qualitatively similar to those obtained previously for the isolated chick TM (Freeman et al., 1994) but different from those obtained for the in vitro mouse TM (Kronester-Frei, 1979a).