The fatty acid composition of lipids of neuronal and glial nuclear fractions isolated from 15-day-old rabbit cerebral cortex

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Abstract
A neuronal nuclear fraction (N1) and a glial nuclear fraction (N2) were isolated from 15 day old rabbit cerebral cortex using the Thompson procedure. More than 56% of the homogenate DNA was recovered in the 2 nuclear fractions, with N1 being the larger by about 8-fold. Fractions N1 had N2 had very similar phospholipid distributions, with phosphatidyl-inositol being a larger component than phosphatidylserine. Fatty acid analyses demonstrated that phosphatidylethanolamine and phosphatidylinositol, individually, had similar fatty acid profiles in fractions N1 and N2, and in nuclear and microsomal fractions derived from homogenates of nerve cell bodies isolated from cerebral cortex of 15 day old rabbits. The nuclear phosphatidylcholines had lower levels of palmitate and higher levels of arachidonate than did microsomal phosphatidylcholines. Molecular species analyses indicated that monoenes (41 mol%), tetraenes (20 mol%) and saturates (13 mol%, composed chiefly of palmitate) were the principal classes of N1 phosphatidylcholines; the diacyl species of phosphatidylethanolamine of this fraction were characterized by high levels of tetraenes (44 mol%), pentaenes (17 mol%) and hexaenes + polyenes (24 mol%). The neutral glycerides of fraction N1 occurred collectively at a level of 0.05 mol/mol phospholipid. Prominent fatty acids of diacylglycerols included palmitate (31%), oleate (20%), arachidonate (14%) and stearate (13%). Triacylglycerols showed a similar pattern but with relatively high levels of linoleate (11%), monoacylglycerols consisted almost entirely of palmitate (33%), stearate (35%), and oleate (24%).