Manevich E M, Lakin K M, Archakov A I, Li V S, Molotkovsky J G, Bezuglov V V, Bergelson L D
Biochim Biophys Acta. 1985 May 28;815(3):455-60. doi: 10.1016/0005-2736(85)90373-6.
Anthryl-labeled fluorescent probes closely mimicking phosphatidylcholine and sphingomyelin were applied to study the state of these phospholipids in the rabbit erythrocyte membrane. At normal cholesterol levels both probes exhibited higher fluorescence polarization values in the membranes than in phospholipid vesicles of similar lipid composition, indicating a decreased fluidity of the probe environment in erythrocyte ghosts. In ghosts prepared from normal erythrocytes no evidence of lateral separation of phosphatidylcholine and sphingomyelin was found. At higher cholesterol levels, however, these lipids appear to segregate. Probably the effect of cholesterol on the erythrocyte membrane lipids involves lipid-protein interactions. At physiological concentrations, prostaglandin E1 only weakly affects the state of phosphatidylcholine and sphingomyelin in erythrocyte membranes. Cholesterol enrichment amplifies the effect of prostaglandin E1. Although the prostaglandin E1-induced changes depended much upon whether the ghosts were enriched with cholesterol in vitro or in vivo, with both types of ghosts effects of prostaglandin E1 were seen at extremely low effector concentrations that may have presented a few molecules of prostaglandin per ghost. The structural and functional significance of these findings is discussed.
应用与磷脂酰胆碱和鞘磷脂紧密模拟的蒽基标记荧光探针来研究兔红细胞膜中这些磷脂的状态。在正常胆固醇水平下，两种探针在膜中的荧光偏振值均高于脂质组成相似的磷脂囊泡中的荧光偏振值，这表明红细胞膜中探针环境的流动性降低。在由正常红细胞制备的膜中，未发现磷脂酰胆碱和鞘磷脂横向分离的证据。然而，在较高胆固醇水平下，这些脂质似乎会分离。胆固醇对红细胞膜脂质的影响可能涉及脂质 - 蛋白质相互作用。在生理浓度下，前列腺素E1对红细胞膜中磷脂酰胆碱和鞘磷脂的状态影响较弱。胆固醇富集增强了前列腺素E1的作用。尽管前列腺素E1诱导的变化在很大程度上取决于膜是在体外还是体内富集胆固醇，但对于这两种类型的膜，在极低的效应物浓度下就可以观察到前列腺素E1的作用，每个膜可能仅存在少数前列腺素分子。本文讨论了这些发现的结构和功能意义。
