Water compartmentalization and extracellular tortuosity after osmotic changes in cerebellum of Trachemys scripta.
Water compartmentalization and extracellular tortuosity after osmotic changes in cerebellum of Trachemys scripta.
复制标题
草龟小脑渗透压变化后的水区划和细胞外曲折。
DOI：
10.1113/jphysiol.1996.sp021354
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Nicholson,C
中科院分区：
文献类型：
--
作者：
Krizaj,D;Rice,ME;Wardle,RA;Nicholson,C
1.采用细胞外扩散分析和湿、干重测定相结合的方法，对不同渗透压下的甲鱼小脑水分区划进行了定量研究。扩散分析还确定了细胞外空间的曲折程度。2.将分离的小脑分别浸泡在正常含氧生理盐水(302molmoL·kg~(-1))、低渗生理盐水(238molmoL·kg~(-1))和一系列高渗生理盐水(高达668molmoL·kg~(-1))中。渗透压随氯化钠含量的变化而变化。3.用离子选择微电极测量四甲基铵离子电致扩散曲线，测定小脑颗粒层的细胞外体积分数和曲度。体积分数在生理盐水中为0.22，在低渗液中为0.12，在最高渗液中为0.60。曲度在生理盐水中为1.70，在低渗中为1.79，在最高渗中为1.50。4.典型分离小脑(包括颗粒层、浦肯野细胞层和分子层)的含水率(湿重-干重)/湿重为82.9%。低渗盐水组为85.2%，高渗盐水组为80.1%。5.结合细胞外体积分数和水分含量的测量，发现低渗溶液导致水分从细胞外向细胞内移动，而高渗溶液导致水从细胞内向细胞外移动，两种情况下总水的变化都相对较小。6.这些结果表明，可以利用离体龟的小脑作为研究光散射或扩散加权磁共振成像的模型系统。
1. Water compartmentalization in the turtle cerebellum subject to media of different osmolalities was quantified by combining extracellular diffusion analysis with wet weight and dry weight measurements. The diffusion analysis also determined the tortuosity of the extracellular space. 2. Isolated cerebella were immersed in normal, oxygenated physiological saline (302 mosmol kg‐1), hypotonic saline (238 mosmol kg‐1) and a series of hypertonic salines (up to 668 mosmol kg‐1). The osmolality was varied by altering the NaCl content. 3. Extracellular volume fraction and tortuosity of the granular layer of the cerebellum were determined from measurements of ionophoretically induced diffusion profiles of tetramethylammonium, using ion‐selective microelectrodes. The volume fraction was 0.22 in normal saline, 0.12 in hypotonic medium and 0.60 in the most hypertonic medium. Tortuosity was 1.70 in the normal saline, 1.79 in the hypotonic and 1.50 in the most hypertonic saline. 4. The water content, defined as (wet weight‐dry weight)/wet weight, of a typical isolated cerebellum (including granular, Purkinje cell and molecular layers) was 82.9%. It increased to 85.2% in hypotonic saline and decreased to 80.1% in the most hypertonic saline. 5. Measurements of extracellular volume fraction and water content were combined to show that hypotonic solutions caused water to move from the extracellular to the intracellular compartment while hypertonic solutions caused water to move from the intracellular to extracellular compartment, with only a relatively small changes in total water in both cases. 6. These results suggest the use of the isolated turtle cerebellum as a model system for studying light scattering or diffusion‐weighted magnetic resonance imaging.