Effros R M, Taki K, Dodek P, Edwards J, Husczuk A, Silverman P, Hukkanen J
Respiratory Division, Harbor-UCLA Medical Center, Torrance, California 90509.
J Appl Physiol (1985). 1988 Feb;64(2):569-76. doi: 10.1152/jappl.1988.64.2.569.
An elutriator was used to study exchange of labeled CO2 and bicarbonate with erythrocytes. Rabbit erythrocytes were suspended by centrifugation in a stream of fluid and exposed to transient injections of an extracellular indicator (125I-albumin or 22Na+), a water indicator (3H2O), and H14CO3- and/or 14CO2. Diffusion of indicators into erythrocytes was judged by comparison of initial concentrations of diffusible and extracellular indicators in the elutriator outflow. It was possible to conduct these experiments at normal hematocrits because any carbonic anhydrase released from erythrocytes by hemolysis was washed away in the elutriator flow, and ambient pH, PO2, and PCO2 were kept constant by the inflow of fresh fluid. Equilibration of HCO3- with erythrocytes was complete during the 7- to 10-s transit time through the chamber. After this exchange was irreversibly inhibited by the anion exchange inhibitor, DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid), addition of carbonic anhydrase (100 mg/dl) accelerated exchange, but acetazolamide (20 mg/dl) was without effect. These observations were consistent with the absence of carbonic anhydrase on the surface of the erythrocytes.
使用淘析器研究标记的二氧化碳和碳酸氢盐与红细胞的交换。通过离心将兔红细胞悬浮在流体流中，并使其短暂暴露于细胞外指示剂（125I-白蛋白或22Na+）、水指示剂（3H2O）以及H14CO3-和/或14CO2中。通过比较淘析器流出物中可扩散指示剂和细胞外指示剂的初始浓度来判断指示剂向红细胞内的扩散情况。由于溶血从红细胞释放的任何碳酸酐酶在淘析器流中被冲走，并且通过新鲜流体的流入使环境pH、PO2和PCO2保持恒定，因此可以在正常血细胞比容下进行这些实验。在通过腔室的7至10秒转运时间内，HCO3-与红细胞的平衡完成。在用阴离子交换抑制剂DIDS（4,4'-二异硫氰基芪-2,2'-二磺酸）不可逆地抑制这种交换后，添加碳酸酐酶（100mg/dl）可加速交换，但乙酰唑胺（20mg/dl）无效。这些观察结果与红细胞表面不存在碳酸酐酶一致。
