FLUORESCENCE STUDIES OF BIOPHYSICAL PROPERTIES OF POLYUN

神经元和视网膜组织中含有大量的磷脂，这些磷脂含有一个或两个长链多不饱和酰基链。进一步完善我们的分析的时间分辨的各向异性衰减的疏水性荧光探针二苯基己三烯（DPH）允许测量的酰基链包装顺序在膜内部与部分的链更接近界面区域。多不饱和酰基链导致最高程度的酰基链紊乱，并产生最高值的酰基链堆积自由体积，这是一个促进G蛋白偶联受体视紫红质的活化构象形成的最大程度的参数。胆固醇已被证明降低酰基链堆积自由体积和视紫红质活化。我们的研究表明，多不饱和磷脂能够抵抗胆固醇的有序化效应，并保持其独特的酰基链堆积特性。最近的研究结果表明，酰基链包装增加渗透压，由于磷脂头部基团的脱水。另一方面，乙醇具有降低酰基链顺序的拮抗作用。这些影响是重要的，在了解体内机制的酒精作用，因为乙醇的影响发生在血浆渗透背景的存在下。这些研究结果具有重要的意义，膜蛋白的功能，并表明，在视网膜和神经元组织中发现的高度不饱和磷脂可以优化受体功能，能够抵抗某些成分变化的影响，如胆固醇含量的增加，并可能调节膜对乙醇的敏感性。- 神经科学、营养失调

Neuronal and retinal tissue are high in phospholipids containingone or two long chain polyunsaturated acyl chains. A further refinement of our analysis of the time-resolved anisotropy decay of the hydrophobic fluorescence probe diphenylhexatriene (DPH) allows a measure of the acyl chain packing order in the membrane interior vs the portion of the chain closer to the interfacial region. Polyunsaturated acyl chains result in the highest degree of acyl chain disorder and produce the highest values of acyl chain packing free volume, a parameter which promotes the greatest degree of formation of the activate conformation of the G protein-coupled receptor, rhodopsin. Cholesterol has been shown to decrease both acyl chain packing free volume and rhodopsin activation. Our studies show that polyunsaturated phospholipids are able to resist the ordering effects of cholesterol and maintain their unique acyl chain packing properties. Recent findings demonstrate that acyl chain packing is increased by increased osmotic stress, due to the dehydration of the phospholipid head group. Ethanol on the other hand has an antagonistic effect of decreasing acyl chain order. These effects are important in understanding in vivo mechanisms of alcohol action since ethanol effects occur in the presence of an osmotic background of plasma. These findings have important implications for integral membrane protein function and suggest that highly unsaturated phospholipids found in retina and neuronal tissue can optimize receptor function, are able to resist the effects of certain compositional variation, such as increases in cholesterol content, and may modulate membrane sensitivity to ethanol. - neurosciences, nutritional disorders