Vélez M, Lillo M P, Acuña A U, González-Rodríguez J
Departamento de Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Spain.
Biochim Biophys Acta. 1995 May 4;1235(2):343-50. doi: 10.1016/0005-2736(95)80023-9.
There are indications that the plasma membrane lipid composition and, in particular, the cholesterol/phospholipid (C/PL) ratio, affects platelet function. As a first approximation to the molecular characterization of the effect of cholesterol on the order, fluidity and lateral heterogeneity of the platelet plasma membrane, the steady-state and time-resolved fluorescence of 1,6-diphenyl-1,3,5-hexatriene (DPH) and trans-parinaric acid (tPnA) has been studied in multibilayer vesicles of phospholipids extracted from human platelet plasma membrane with different cholesterol/phospholipid molar ratios modified in vitro from 0.07 to 0.9. The DPH studies show that the increased presence of cholesterol has a stronger effect on the order than on the fluidity of the bilayer, as has been previously observed in other lipid membranes. On the other hand, from the analysis of the fluorescence kinetics of tPnA we conclude that a higher cholesterol content gives rise to an increase of the heterogeneity of the bilayer, due to a larger fraction of solid-like lipid domains. These domains contain a cholesterol concentration much higher than the macroscopic average value.
有迹象表明，质膜脂质组成，尤其是胆固醇/磷脂（C/PL）比率，会影响血小板功能。作为对胆固醇对血小板质膜的有序性、流动性和横向异质性影响进行分子表征的初步近似，研究了1,6 - 二苯基 - 1,3,5 - 己三烯（DPH）和反式 - 十八碳四烯酸（tPnA）在从人血小板质膜提取的磷脂多层囊泡中的稳态荧光和时间分辨荧光，这些囊泡的胆固醇/磷脂摩尔比在体外从0.07改变到0.9。DPH研究表明，胆固醇含量增加对双层膜有序性的影响比对流动性的影响更强，正如之前在其他脂质膜中所观察到的那样。另一方面，通过对tPnA荧光动力学的分析，我们得出结论，较高的胆固醇含量会导致双层膜异质性增加，这是由于类固态脂质域的比例更大。这些域中的胆固醇浓度远高于宏观平均值。
