MOLECULAR-SPECIES OF CHOLINE AND ETHANOLAMINE GLYCEROPHOSPHOLIPIDS INRAT-BRAIN MYELIN DURING DEVELOPMENT

The composition of the molecular species of various phospholipid subcl asses was examined in myelin isolated from brain of 15-, 21- and 90 da y-old rats. The molecular species of diacylglycerophosphocholine (PtdC ho), diacylglycerophosphoethanolamine (PtdEtn) and plasmenylethanolami ne (PlsEtn) were quantified by high-performance liquid chromatography (HPLC) after phospholipase C treatment and dinitrobenzoyl derivatizati on. In rat brain myelin, each phospholipid subclass showed a specific pattern of molecular species that changed during development. PtdCho c ontained large amounts of saturated/monounsaturated and disaturated sp ecies and low amounts of saturated/polyunsaturated species. During bra in development, the levels of saturated/monounsaturated rated molecula r species increased whereas those of the disaturated and saturated/pol yunsaturated species decreased. PtdEtn were characterized by their low levels of disaturated species and a high content of saturated/monouns aturated and saturated/polyunsaturated species, of which those contain ing fatty acids of the n-3 series decreased, whereas those containing fatty acids of the n-6 series did not change during brain development. The levels of saturated/monounsaturated species increased in PtdEtn. No disaturated molecular species could be detected in PlsEtn. This alk enylacyl subclass contained large amounts of saturated/polyunsaturated , saturated/monounsaturated and dimonounsaturated molecular species. D uring development, the levels of saturated/polyunsaturated molecular s pecies decreased while those of the two others increased. The data ind icated that myelin sheaths undergo phospholipid changes during brain d evelopment and maturation.