Kern D F, Malik A B
J Appl Physiol (1985). 1985 Feb;58(2):372-5. doi: 10.1152/jappl.1985.58.2.372.
We examined the effects of decreases in perfusate concentrations of calcium and magnesium on the pulmonary vascular permeability in the isolated perfused rabbit lung. The albumin permeability-surface area product (PS) and the albumin reflection coefficient (sigma) were determined in the same lung using 125I- and 131I-labeled albumin tracers. Decreases in vascular Ca2+ and Mg2+ concentrations were induced by adding ethylenediaminetetraacetic acid (EDTA) to the perfusate. Decreases in the concentration of these cations resulted in an increase in the PS from a control value of 1.18 +/- 0.13 X 10(-3) to 7.69 +/- 0.75 X 10(-3) cm3 X min-1 X g wet lung wt-1 and a decrease in the sigma from 0.96 +/- 0.01 to 0.74 +/- 0.02. The decrease in sigma suggests an increase in the calculated equivalent pore radius from 44 to 63 A. The results indicate that Ca2+ and Mg2+ play a role in the maintenance of normal pulmonary vascular permeability to proteins.
我们研究了灌注液中钙和镁浓度降低对离体灌注兔肺肺血管通透性的影响。使用¹²⁵I和¹³¹I标记的白蛋白示踪剂，在同一肺中测定白蛋白通透系数-表面积乘积（PS）和白蛋白反射系数（σ）。通过向灌注液中添加乙二胺四乙酸（EDTA）来降低血管中Ca²⁺和Mg²⁺的浓度。这些阳离子浓度的降低导致PS从对照值1.18±0.13×10⁻³增加到7.69±0.75×10⁻³ cm³·min⁻¹·g湿肺重⁻¹，σ从0.96±0.01降低到0.74±0.02。σ的降低表明计算出的等效孔半径从44 Å增加到63 Å。结果表明，Ca²⁺和Mg²⁺在维持肺血管对蛋白质的正常通透性中起作用。
