Ethanol and the physical properties of brain membranes: fluorescence studies.
Ethanol and the physical properties of brain membranes: fluorescence studies.
复制标题
乙醇和脑膜的物理特性：荧光研究。
作者：
R. Harris;F. Schroeder
从小鼠脑中制备突触质膜和髓鞘，并使用荧光探针分子1，6-二苯基-1，3，5-己三烯（DPH）和1-氨基芘评价它们的物理性质。当突触质膜在体外暴露于低浓度（10-20 mM）的乙醇时，DPH（膜核心的探针）的吸收校正的荧光输出和荧光偏振降低。1-氨基芘（膜表面的探针）的荧光仅受高乙醇浓度的影响。乙醇没有改变突触质膜中DPH的激发或发射最大值，这表明它没有改变探针附近的极性。与完整的突触质膜相比，在髓鞘膜和从髓鞘或突触质膜提取的脂质中的DPH荧光对乙醇的影响不太敏感。在不同温度下的荧光偏振分析表明，乙醇改变了膜脂的相行为。这些结果表明，低，生理相关浓度的乙醇选择性地破坏突触膜的疏水核心。完整的突触膜的敏感性进行了讨论，在酒精破坏的脂质-蛋白质相互作用。
Synaptic plasma membranes and myelin were prepared from mouse brain and their physical properties were evaluated by using the fluorescent probe molecules 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-aminopyrene. The absorption-corrected fluorescence output and fluorescence polarization of DPH (a probe of the membrane core) were decreased when synaptic plasma membranes were exposed in vitro to low concentrations (10-20 mM) of ethanol. Fluorescence of 1-aminopyrene (a probe of the membrane surface) was affected only by high ethanol concentrations. Ethanol did not alter the excitation or emission maxima of DPH in synaptic plasma membranes, which indicates that it did not alter polarity in the vicinity of the probe. Compared with the intact synaptic plasma membranes, DPH fluorescence in myelin membranes and in lipids extracted from myelin or synaptic plasma membranes was less sensitive to the effects of ethanol. Analysis of fluorescence polarization at various temperatures indicated that ethanol altered the phase behavior of membrane lipids. These results indicate that low, physiologically relevant concentrations of ethanol selectively fluidize the hydrophobic core of synaptic membranes. The sensitivity of intact synaptic membranes is discussed in terms of lipid-protein interactions disrupted by ethanol.