Effects of osmotic stress on dextran diffusion in rat neocortex studied with integrative optical imaging.
Effects of osmotic stress on dextran diffusion in rat neocortex studied with integrative optical imaging.
复制标题
通过综合光学成像研究渗透应激对大鼠新皮质中葡聚糖扩散的影响。
DOI：
10.1152/jn.1999.81.5.2501
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发表时间：
1999
影响因子：
2.5
通讯作者：
Tao,L
中科院分区：
文献类型：
--
作者：
Tao,L
渗透压对大鼠新皮质葡聚糖扩散影响的积分光学成像研究。 本研究探讨了如何葡聚糖（Mr= 3,000）扩散在大鼠皮层切片时，渗透压的洗浴人工脑脊液改变了不同的NaCl含量。表观扩散系数，D*，在新皮层区域使用荧光分子和集成光学成像（IOI）方法测量。主要结果如下：1）在34°C等渗（300 mOsm）人工脑脊液中，大鼠新皮层的D * 值为D * = 0.68 ± 0.01 × 10− 6cm 2s −1（平均值± SE，n= 78），并且可以在几分钟内通过改变细胞外渗透压来改变。2）低渗应力（高达−100 mOsm）使D * 下降35%，并且当切片返回等渗介质时完全可逆。进一步低渗至-150 mOsm使D * 进一步降低，但解除后D* 超过对照值。3）+50 mOsm的高渗应力使D * 增加，但最大可逆增加仅为15%。进一步的高渗应力（至+200 mOsm）不会导致D * 进一步增加，并且在去除应力后，D* 低于对照值。D * 的变化被认为与组织中细胞的体积变化有关：低渗溶液引起细胞肿胀，导致细胞外空间减少和细胞外基质压缩，从而使葡聚糖扩散更加受阻。高渗溶液则有相反的效果。海马CA 1区的胞外场电位的记录表明，在暴露于极端低渗或高渗应力后返回到等渗溶液中，神经元保留其产生突触反应的能力。
Effects of osmotic stress on dextran diffusion in rat neocortex studied with integrative optical imaging. This study investigated how dextran (Mr= 3,000) diffused in rat cortical slices when the osmolarity of the bathing artificial cerebrospinal fluid was altered by varying the NaCl content. The apparent diffusion coefficient,D*, was measured in the neocortex region using fluorescent molecules and the integrative optical imaging (IOI) method. The main results were:1) the value ofD* in rat neocortex in the isotonic (300 mOsm) artificial cerebrospinal fluid at 34°C wasD* = 0.68 ± 0.01 × 10−6cm2s−1(mean ± SE,n= 78) and it could be changed within minutes by varying the extracellular osmolarity.2) Hypotonic stresses up to −100 mOsm decreasedD* by 35% and were fully reversible when the slices were returned to the isotonic medium. Further hypotonic stress to −150 mOsm caused further decrease inD* but after removal of the stress,D* overshot its control value.3) Hypertonic stress of +50 mOsm increasedD*, but the maximum reversible increase inD* was only 15%. Further hypertonic stress (to +200 mOsm) did not cause any further increase inD* and, after removal of the stress,D* undershot the control value. The changes inD* are thought to be related to volume changes of cells in tissue: hypotonic solutions caused cell swelling, resulting in reduced extracellular space and compressed extracellular matrix so that the dextran diffusion was more hindered. Hypertonic solutions had the opposite effect. Recordings of extracellular field potentials in the hippocampal CA1 region demonstrated that, on return to the isotonic solution after exposure to an extreme hypotonic or hypertonic stress, the neurons retained their ability to generate synaptic responses.