人红细胞摄入 Eu(Cit)23-阴离子通道机制的研究

研究了Eu(Cit)2^3-进入人红细胞的机制。在人红细胞与含不同浓度的Eu(Cit)2^3-的等渗缓冲液温育后。用ICP－MS测定胞浆及膜中Eu的含量，并考察了阴离子通道抑制剂DIDS，温度及pH的影响，制备了人红细胞膜正面向外囊泡（ROV）和内翻包囊泡（IOV）并研究了它们对Eu(Cit)2^3-的摄取及DIDS的影响。结果表明，Eu(Cit)2^3-可以与细胞膜结合并进入红细胞内，DIDS强烈抑制红细胞对Eu(Cit)2^3-的摄入；温度，pH对细胞摄入有显著影响，ROV和IOV可以摄入Eu(Cit)2^3-，但DIDS只抑制ROV的摄入，对IOV的摄入无影响。Eu(Cit)2^3-进入人红细胞具有阴离子通道机制的各种特征。阴离子通道是稀土柠檬酸络合物Eu(Cit)2^3-进入红细胞的途径之地。

Anion Channel Mechanism of Eu(Cit)23- Transport into Human Erythrocytes

After incubation of human erythrocytes with Eu(Cit) 2 3- (Cit=citratic group), Eu contents were determined both in cellular membrane and cytoplama by ICP MS. The effect of DIDS (an inhibitor of anion channel), pH of incubation medium and temperature on the cellular uptake of Eu(Cit) 2 3- were examined. The right side out vesicles(ROV) and inside out vesicles(IOV) from human erythrocyte membranes were prepared, and these vesicles were used to study the uptake of Eu(Cit) 2 3- and influence of DIDS. Eu(Cit) 2 3- can bind to cellular membranes and transport into human erythrocytes. DIDS inhibits strongly the transmembrane transport of Eu(Cit) 2 3- , and the cellular uptake of Eu(Cit) 2 3- depends markedly on the temperature and pH values of solution. ROVs and IOVs all take up Eu(Cit) 2 3- , and DIDS inhibits partly ROVs for the uptake of Eu(Cit) 2 3- , but the DIDS inhibition is not observable for IOVs. These facts strongly evidence that uptake of human erythrocyte for Eu(Cit) 2 3- displays the natures of anion channel mechanism. The anion channel is thus shown to be one of the pathways by which complexes Ln(Cit) 2 3- of rare earth ions with citrate enter human erythrocytes.