SINGLE CAPILLARY-PERMEABILITY TO PROTEINS HAVING SIMILAR SIZE BUT DIFFERENT CHARGE
SINGLE CAPILLARY-PERMEABILITY TO PROTEINS HAVING SIMILAR SIZE BUT DIFFERENT CHARGE
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DOI：
10.1152/ajpheart.1988.254.2.h304
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发表时间：
1988-02-01
影响因子：
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通讯作者：
CURRY, FE
中科院分区：
文献类型：
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作者：
ADAMSON, RH;HUXLEY, VH;CURRY, FE
我们研究了溶质电荷调节具有连续内皮的微血管中的跨毛细血管交换的假设。两种球状蛋白，α-乳清蛋白和核糖核酸酶，具有大致相同的大小（摩尔重量分别为14,176和13,683）但不同的净电荷（分别为-10和14）是测试溶质。每种溶质都用荧光探针四甲基罗丹明异硫氰酸盐进行标记。标记并没有显着改变溶质的大小，但使每种溶质的负电荷增加一个价位单位。体内荧光显微镜技术 [Huxley 等人，Am. J.生理学。 252（Heart Circ. Physiol. 21）：H188-H197，1987]用于测量14-16℃下青蛙肠系膜单个微血管中的溶质渗透系数（P）。当毛细管压力为10cmH2O时测量的α-乳清蛋白的平均P为2.1倍。 10-6 cm/s，核糖核酸酶的平均 P 为 4.3 倍。 10-6 厘米/秒。我们的结果符合青蛙肠系膜微血管的跨毛细血管通路带负电的假设。使用唐南型静电分配模型，路径中的电荷密度估计为 11.4 meq/l。将测得的 Ps 与青蛙肠系膜微血管中小溶质的 Ps 进行比较表明，与溶质电荷相比，分子大小是连续毛细血管中溶质渗透性的比例更重要的决定因素。
We investigated the hypothesis that solute charge modulates transcapillary exchange in microvessels with continuous endothelium. Two globular proteins, .alpha.-lactalbumin and ribonuclease, having approximately the same size (mol wt 14,176 and 13,683, respectively) but different net charge (-10 and 14 respectively) were test solutes. Each solute was labeled with the fluorescent probe tetramethylrhodamine isothiocyanate. Labeling did not significantly change solute size, but increased negative charge on each solute by one valency unit. An in vivo fluorescent microscope technique [Huxley et al., Am. J.Physiol. 252 (Heart Circ. Physiol. 21): H188-H197, 1987] was used to measure solute permeability coefficients (P) in single microvessels of frog mesentery at 14-16.degree.C. The mean P for .alpha.-lactalbumin, measured when capillary pressure was 10 cmH2O, was 2.1 .times. 10-6 cm/s and the mean P for ribonuclease was 4.3 .times. 10-6 cm/s. Our results conform to the hypothesis that the transcapillary pathways of frog mesenteric microvessels are negatively charged. With the use of a Donnan-type model for electrostatic partitioning, charge density in the pathway is estimated as 11.4 meq/l. Comparison of measured Ps with those for small solutes in frog mesenteric microvessels indicates that molecular size is a proportionally more significant determinant of solute permeability in continuous capillaries than in solute charge.