Sodium ion apparent diffusion coefficient in living rat brain
Sodium ion apparent diffusion coefficient in living rat brain
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DOI：
10.1002/mrm.20444
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发表时间：
2005-05-01
影响因子：
3.3
通讯作者：
Neil, JJ
中科院分区：
文献类型：
--
作者：
Goodman, JA;Kroenke, CD;Neil, JJ
测定了Na+在活体大鼠脑内的表观扩散系数（ADC）。脑细胞外与细胞内的Na+含量比类似于8：2，这与这些空间中水的含量比相反。因此，Na+的ADC主要受细胞外空间中运动的影响，并且Na+可以被视为该空间中运动的报告分子。同样，水ADC由细胞内运动主导。脑Na+ ADC为1.15 +/- 0.09 μ m（2）/ms，是37 ℃时水Na+自由扩散系数（无D）的61%（1.9 μ m（2）/ms），而脑水ADC是37 ℃时水无D的28%（3 μ m（2）/ms）。这表明细胞外空间内分子种类的ADC大致是细胞内空间内分子种类的ADC的两倍。在死后的大脑，Na+和水减少到17%的各自的D-自由值。这些结果是一致的Na+和水ADC值共享相同的生物物理决定因素在死后的大脑。在活体脑组织中观察到的Na+和水ADC/D-自由比率之间的差异可能归因于细胞外环境阻碍分子位移比细胞内环境少两倍。(c)2005 Wiley-Liss，Inc.
The apparent diffusion coefficient (ADC) of Na+ was determined in live rat brain. The brain extracellular-to-intracellular Na+ content ratio is similar to 8:2, which is the inverse of that for water in these spaces. Consequently, the ADC of Na+ is primarily affected by motion in the extracellular space, and Na+ can be viewed as a reporter molecule for motion in that space. Likewise, water ADC is dominated by intracellular motion. The brain Na+ ADC was 1.15 +/- 0.09 mu m(2)/ms, which is 61% of the aqueous Na+ free diffusion coefficient (D-free) at 37 degrees C (1.9 mu m(2)/ms), while the ADC for brain water is 28% of the water D-free at 37 degrees C (3 mu m(2)/ms). This suggests that the ADC of molecular species within the extracellular space is roughly twofold that within the intracellular space. In postmortem brain, both Na+ and water decrease to 17% of the respective D-free values. These results are consistent with Na+ and water ADC values sharing the same biophysical determinants in postmortem brain. The observed difference between Na+ and water ADC/D-free ratios in living brain tissue may be attributable to the extracellular environment hindering molecular displacements twofold less than the intracellular environment. (c) 2005 Wiley-Liss, Inc.