The fatty acid composition of phosphoglycerides of nerve cell bodies isolated in bulk from rabbit cerebral cortex: changes during development and positional distribution

Abstract

Analyses were made of the component fatty acids of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylinositol (PI) of nerve cell bodies isolated in bulk from cerebral cortex of rabbits of 8, 15, and 22 days and 9 weeks of age. PC has palmitate as its major saturated fatty acid and this showed a decrease with age (8 days to 9 weeks) from 46 to 39% of the total fatty acid. Stearate, the dominant saturate in PE, (22–23%), PI (35–37%), and PS (42–44%), remained relatively constant with age, although there was an increase in stearate in PC (6 to 10%) over this time period. Of the four phosphatides, PC had the highest levels of monoenoic fatty acids, showing progressive increases in oleate (23 to 28%) and declines in palmitoleate (6 to 2%). During development, the level of arachidonate (20:4) remained relatively constant in PC (10–11%) and PI (47–48%), but declined in PE (26 to 21%) and PS (8 to 5%). Conversely, the levels of docosahexaenoate (22:6) rose in PE (11 to 17%) and PS (16 to 21%) over the same time period. Phospholipase A2 hydrolyses of these phosphoglycerides showed stearate principally at position 1 and polyunsaturates (e.g., 20:4, 22:6) almost exclusively at position 2. Palmitate and oleate were generally found in greater abundance at position 1, with the exception of PC where both these fatty acids were almost equally distributed between positions 1 and 2. The existence of dipalmitoyl and 1-oleoyl-2-palmitoyl lecithins in nerve cell bodies may thus be suggested.