Microvascular albumin permeability in isolated perfused lung: effects of EDTA.
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.
D000818:Animals; D002118:Calcium / Q000502:physiology; D002199:Capillary Permeability / Q000187:drug effects*; D004492:Edetic Acid / Q000494:pharmacology*; D005260:Female; D008168:Lung / Q000098:blood supply* / Q000378:metabolism; D008274:Magnesium / Q000502:physiology; D008297:Male; D008833:Microcirculation / Q000502:physiology; D010477:Perfusion; D011817:Rabbits; D012711:Serum Albumin, Radio-Iodinated
D012711:Serum Albumin, Radio-Iodinated; D004492:Edetic Acid; D008274:Magnesium; D002118:Calcium