Orsenigo M N, Tosco M, Faelli A
Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, Italy.
J Membr Biol. 1991 Oct;124(1):13-9. doi: 10.1007/BF01871360.
Basolateral membrane vesicles isolated from rat jejunal enterocyte and well purified from brush border contamination were tested to examine Cl and HCO3 movements. Uptake experiments provided no evidence for a coupling between Na and HCO3 fluxes; K-HCO3 and K-Cl cotransports also could be excluded. Transport studies revealed the presence of a Cl/HCO3 exchanger accepting other anions and inhibitable by the disulfonic stilbenes SITS and DIDS. We can exclude that the evidenced HCO3-dependent Cl uptake is due to brush border contamination, since in jejunal brush border membranes this mechanism, if present, has a very low transport rate. Besides the Cl/HCO3 antiporter, a Cl-conductive pathway seems to exist in jejunal basolateral membranes.
从大鼠空肠肠上皮细胞分离并从刷状缘污染中充分纯化的基底外侧膜囊泡，用于检测氯离子（Cl）和碳酸氢根离子（HCO₃）的转运。摄取实验没有提供钠离子（Na）与HCO₃通量偶联的证据；钾离子（K）-HCO₃和K-Cl协同转运也可排除。转运研究表明存在一种Cl/HCO₃交换体，它能接受其他阴离子，并可被二磺酸芪类化合物SITS和DIDS抑制。我们可以排除所证实的依赖HCO₃的Cl摄取是由于刷状缘污染，因为在空肠刷状缘膜中，这种机制（如果存在）的转运速率非常低。除了Cl/HCO₃反向转运体，空肠基底外侧膜中似乎还存在一条Cl传导途径。
