THEORETICAL-MODEL FOR GLOMERULAR-FILTRATION OF CHARGED SOLUTES
THEORETICAL-MODEL FOR GLOMERULAR-FILTRATION OF CHARGED SOLUTES
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DOI：
10.1152/ajprenal.1980.238.2.f126
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发表时间：
1980-01-01
影响因子：
--
通讯作者：
JAMIESON, JM
中科院分区：
文献类型：
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作者：
DEEN, WM;SATVAT, B;JAMIESON, JM
以往的实验研究表明，在一定分子大小下，肾小球毛细血管壁对多阴离子的通过限制大于中性大分子，对中性大分子的转运限制大于多阳离子。这种电荷选择性的理论模型是基于以下主要假设建立的：所有离子（示踪大分子和单价阳离子和阴离子）服从修正的能斯特-普朗克通量表达式，包括对流和尺寸选择延迟；毛细管壁固定负电荷均匀分布；和唐南平衡存在于膜的表面。为了允许模型的具体应用，我们测量了硫酸葡聚糖（DS）和二乙基氨基乙基葡聚糖（DEAE）的窄组分的电泳迁移率，并用于估计有效分子电荷作为分子大小的函数。根据这些测量和先前报道的正常慕尼黑- wistar大鼠DS和DEAE的分数间隙数据，毛细血管壁的表观固定电荷浓度为120-170 meq/l。本文还讨论了膜电荷对水过滤和经毛细血管电位差的影响。
Previous experimental studies revealed that for a given molecular size, the glomerular capillary wall restricts the passage of polyanions more than that of neutral macromolecules, and restricts transport of the latter more than that of polycations. A theoretical model of this charge-selectivity was developed based on the following principal assumptions: all ions (tracer macromolecule and univalent cations and anions) obey a modified Nernst-Planck flux expression, including terms for convection and size-selective retardation; the capillary wall has a homogeneous distribution of fixed negative charges; and Donnan equilibria exist at the surfaces of this membrane. To allow specific application of the model, electrophoretic mobilities of narrow fractions of dextran sulfate (DS) and diethylaminoethyl dextran (DEAE) were measured and used to estimate effective molecular charge as a function of molecular size. Based on these measurements and fractional clearance data for DS and DEAE reported previously for the normal Munich-Wistar rat, the capillary wall has an apparent fixed charge concentration of 120-170 meq/l. The effects of this membrane charge on the filtration of water and on the transcapillary electrical potential difference were also discussed.