Park C C, Hennessey T, Ahmed Z
Departments of Physiology, State University of New York, Buffalo.
J Neurochem. 1990 Nov;55(5):1537-45. doi: 10.1111/j.1471-4159.1990.tb04936.x.
Modifications of plasma membrane acyl-linked phospholipid fatty acid composition were produced by supplementing the culture medium with essential fatty acids. The plasma membrane fraction was purified by Percoll gradient centrifugation from dissociated fetal rat brain cells grown in a serum-free culture medium. Both the concentration dependence and the time course of the modifications were examined. Supplementation of the medium with essential polyunsaturated fatty acid, linolenic acid (18:3 omega 3) or linoleic acid (18:2 omega 6), produced incorporation of the elongated and desaturated products of omega 3 or omega 6 class, respectively, i.e., the incorporation was class specific. Within each class, the most unsaturated and elongated members, i.e., terminal members, were preferentially incorporated until they reached a maximum concentration within 6-7 days. At higher concentrations of supplemented fatty acids, additional class specific incorporation in plasma membrane was produced by an increase in the concentration of intermediate members. At the same time, the concentration of monounsaturated fatty acids declined and that of saturated fatty acids remained unchanged. The modifications in fatty acid composition were reversible, with the time course similar to that of incorporation. The total plasma membrane phospholipid and sterol contents did not change with alterations of fatty acid composition, but did change with time in culture. This preparation should prove useful for investigating the role of polyunsaturated fatty acids in brain cell functions, including neuronal excitability.
通过在培养基中添加必需脂肪酸来改变质膜酰基连接的磷脂脂肪酸组成。质膜部分是从无血清培养基中生长的解离胎鼠脑细胞中通过Percoll梯度离心法纯化得到的。研究了修饰的浓度依赖性和时间进程。在培养基中添加必需多不饱和脂肪酸，亚麻酸（18:3 ω3）或亚油酸（18:2 ω6），分别导致ω3或ω6类的延长和去饱和产物的掺入，即掺入具有类特异性。在每一类中，最不饱和和延长的成员，即末端成员，优先掺入，直到它们在6-7天内达到最大浓度。在补充脂肪酸的较高浓度下，中间成员浓度的增加导致质膜中额外的类特异性掺入。同时，单不饱和脂肪酸的浓度下降，饱和脂肪酸的浓度保持不变。脂肪酸组成的修饰是可逆的，其时间进程与掺入相似。质膜总磷脂和甾醇含量不随脂肪酸组成的改变而变化，但随培养时间而变化。这种制剂对于研究多不饱和脂肪酸在脑细胞功能中的作用，包括神经元兴奋性，应该是有用的。
