Abstract

We have studied the CO₂ permeability of the erythrocyte membrane of the rat using a mass spectrometric method that employs ¹⁸O-labelled CO₂. The method yields, in addition, the intraerythrocytic carbonic anhydrase activity and the membrane HCO₃⁻ permeability. For normal rat erythrocytes, we find at 37 °C a CO₂ permeability of 0.078 ± 0.015 cm/s, an intracellular carbonic anhydrase activity of 64,100, and a bicarbonate permeability of 2.1 × 10⁻³cm/s. We studied whether the rat erythrocyte membrane possesses protein CO₂ channels similar to the human red cell membrane by applying the potential CO₂ channel inhibitors pCMBS, Dibac, phloretin, and DIDS. Phloretin and DIDS were able to reduce the CO₂ permeability by up to 50%. Since these effects cannot be attributed to the lipid part of the membrane, we conclude that the rat erythrocyte membrane is equipped with protein CO₂ channels that are responsible for at least 50% of its CO₂ permeability.

摘要

我们使用质谱法研究了大鼠红细胞膜的 CO ₂渗透性，该方法采用¹⁸ O-标记的 CO ₂。此外，该方法产生红细胞内碳酸酐酶活性和膜HCO ₃ ^-渗透性。对于正常大鼠红细胞，我们发现在 37°C 下，CO ₂渗透率为 0.078 ± 0.015 cm/s，细胞内碳酸酐酶活性为 64,100，碳酸氢盐渗透率为 2.1 × 10 ^-3 cm/s。我们通过应用潜在的 CO ₂研究了大鼠红细胞膜是否具有类似于人红细胞膜的蛋白质 CO ₂通道通道抑制剂 pCMBS、Dibac、根皮素和 DIDS。Phloretin 和 DIDS 能​​够将 CO ₂渗透率降低多达 50%。由于这些影响不能归因于膜的脂质部分，因此我们得出结论，大鼠红细胞膜配备了蛋白质 CO ₂通道，该通道负责至少 50% 的 CO ₂渗透性。