一种测定脑细胞外液体积并证明其与脑脊液相通的新方法

A new approach for determining the volume of cerebral cellular fluid and demonstration of its communication with C.S.F.

Friede R L, Hu K H

J Physiol. 1971 Oct;218(2):477-93. doi: 10.1113/jphysiol.1971.sp009629.

Abstract

A new technique is presented for determining the volume of extracellular space in bowfin (Amia calva) brain during in vitro incubation. It consists of solving simultaneous equations which are applied to determine the volume of extracellular space as well as intracellular marker concentration. This technique allows for a better insight into the redistribution of marker between incubation medium and extracellular space as well as between extracellular and intracellular space.2. Na(+), K(+) and Cl(-) equilibrated within 10-15 min between incubation medium and extracellular space. There was no evidence of a homoeostatic mechanism controlling the concentration of these ions in the extracellular fluid, which appeared to be in equilibrium with cerebrospinal fluid. The extracellular spaces of these ions were identical: Na(+), 23.4; K(+), 23.3 and Cl(-), 23.2%.3. Sorbitol equilibrated with the extracellular fluid within 45 min and indicated an extracellular space of 22.6%, nearly identical with that for electrolytes.4. Vastly different ;spaces' were obtained for [(3)H]methoxy inulin, which equilibrated within 45 min with a 13% space and [(14)C]carboxyl inulin, which showed a 46% space value for only 30 min. The difference may be explained by marker decomposition. The 9% difference between the [(3)H]methoxy inulin and sorbitol spaces may be explained by a ;packing' factor attributable to molecular size.

摘要

本文介绍了一种在体外孵育过程中测定弓鳍鱼（Amia calva）脑细胞外间隙体积的新技术。该技术包括求解联立方程，用于确定细胞外间隙体积以及细胞内标记物浓度。此技术有助于更深入地了解标记物在孵育介质与细胞外间隙之间以及细胞外与细胞内间隙之间的重新分布情况。
Na⁺、K⁺和Cl⁻在孵育介质与细胞外间隙之间于10 - 15分钟内达到平衡。没有证据表明存在一种稳态机制来控制细胞外液中这些离子的浓度，细胞外液似乎与脑脊液处于平衡状态。这些离子的细胞外间隙相同：Na⁺为23.4%；K⁺为23.3%；Cl⁻为23.2%。
山梨醇在45分钟内与细胞外液达到平衡，其显示的细胞外间隙为22.6%，与电解质的细胞外间隙几乎相同。
对于[³H]甲氧基菊粉和[¹⁴C]羧基菊粉，得到了差异极大的“间隙”值。[³H]甲氧基菊粉在45分钟内达到平衡，间隙为13%；而[¹⁴C]羧基菊粉在仅30分钟时间隙值为46%。这种差异可能是由于标记物分解所致。[³H]甲氧基菊粉与山梨醇间隙之间9%的差异可能是由分子大小导致的“堆积”因素所解释。