Elgavish A, Elgavish G A
J Membr Biol. 1985;88(2):123-30. doi: 10.1007/BF01868426.
The in vitro effect of ethanol on membrane structure and transport properties was studied in isolated renal brush border membrane vesicles. 31P-NMR studies showed a dose-dependent increase in the quantity of an isotropic, possibly inverted-micellar component of the renal brush-border membrane as a result of treatment with ethanol. Such structures have been shown to be instrumental in the translocation of material across membrane bilayers. A 23Na-NMR study of Na+ exchange in artificial phosphatidylcholine liposomes indicated that ethanol (0.1%) was capable of rendering the otherwise inert vesicles permeable to sodium, supporting the idea that ethanol may exert its action via a direct effect on the structure of the phospholipid bilayer. In the isolated renal brush-border membrane vesicles, like in the artificial liposomes, amiloride-insensitive pathways of Na+ transport were shown to be markedly activated by ethanol. These results were consistent with the inhibitory effect ethanol had on Na+ gradient-dependent transport systems such as the Na+ gradient-dependent D-glucose transport and Na+/H+ exchange. In conclusion, our results indicate that ethanol exerts its effect on the renal brush-border membrane by causing a structural change in the phospholipid bilayer which activates sodium intake. The inhibitory effect of ethanol on glucose uptake and Na+/H+ exchange is secondary, as a result of the dissipation of the energy-producing Na+ gradient.
在分离的肾刷状缘膜囊泡中研究了乙醇对膜结构和转运特性的体外作用。31P-NMR研究表明，用乙醇处理后，肾刷状缘膜的各向同性、可能是反胶束成分的量呈剂量依赖性增加。已证明这种结构有助于物质跨膜双层转运。对人工磷脂酰胆碱脂质体中Na+交换的23Na-NMR研究表明，乙醇（0.1%）能够使原本惰性的囊泡对钠具有通透性，支持乙醇可能通过对磷脂双层结构的直接作用发挥其作用的观点。在分离的肾刷状缘膜囊泡中，与人工脂质体一样，Na+转运的amiloride不敏感途径被证明可被乙醇显著激活。这些结果与乙醇对Na+梯度依赖性转运系统（如Na+梯度依赖性D-葡萄糖转运和Na+/H+交换）的抑制作用一致。总之，我们的结果表明，乙醇通过引起磷脂双层结构变化从而激活钠摄取，对肾刷状缘膜发挥作用。乙醇对葡萄糖摄取和Na+/H+交换的抑制作用是次要的，是由于产生能量的Na+梯度消散所致。
