The interactions of molecules such as short-chain alcohols with the mammalian plasma membrane are thought to play a role in anesthetic effects. We have examined the concentration-dependent effects of ethanol and n-butanol on the fluidity of planar model lipid bilayer structures supported on mica. The supported model bilayer was composed of 1,2-dioleoyl-sn-phosphatidylcholine (DOPC), cholesterol, and sphingomyelin, and the bilayers were formed by vesicle fusion from extruded unilamellar vesicles (133 nm diameter, polydispersity index of 0.17). Controlled amounts of ethanol and n-butanol were added during vesicle deposition. Translational diffusion constants were obtained utilizing fluorescence recovery after photobleaching (FRAP) measurements on the micrometer scale with perylene as the fluorophore. The translational diffusion constants increased and then decreased with increasing ethanol concentration, with the bilayer structure degrading at ca. 0.8 M ethanol. A similar trend was observed for n-butanol at lower alcohol concentrations owing to greater interactions with phospholipid bilayer constituents. For n-butanol, the integrity of the planar bilayer structure deteriorated at ca. 0.4 M n-butanol. The results are consistent with bilayer interdigitation.

人们认为短链醇等分子与哺乳动物质膜的相互作用在麻醉效果中发挥作用。我们研究了乙醇和正丁醇对云母支撑的平面模型脂质双层结构的流动性的浓度依赖性影响。支持的模型双层由 1,2-二油酰-sn-磷脂酰胆碱 (DOPC)、胆固醇和鞘磷脂组成，双层是由挤出的单层囊泡（直径 133 nm，多分散指数为 0.17）通过囊泡融合形成。在囊泡沉积过程中添加受控量的乙醇和正丁醇。利用以苝为荧光团的微米级光漂白后​​荧光恢复 (FRAP) 测量获得平移扩散常数。随着乙醇浓度的增加，平移扩散常数先增加后减少，双层结构在大约 1时降解。 0.8 M 乙醇。由于与磷脂双层成分的相互作用更大，在较低酒精浓度下，正丁醇也观察到类似的趋势。对于正丁醇，平面双层结构的完整性在约. 0.4M正丁醇。结果与双层交指一致。