MYELINATION IN RAT BRAIN: CHANGES IN MYELIN COMPOSITION DURING BRAIN MATURATION

摘要: — Myelin was isolated from rat brains during development by a procedure giving fractions of constant purity at all ages. The lipid composition these and whole littermates determined. amount myelin recovered per brain nearly linear function the logarithm age youngest (15 days) to oldest (425 animals studied. With exception earliest point, accounted for approximately 40 cent total galactolipid, evidence that fraction (calculated be 60 cent) Although lipid-protein ratio with age, marked changes were seen in amounts cerebroside, sulphatide, phosphatidylcholine desmosterol. galactolipid increased 21 15 days about 31 maturity. Phosphatidylcholine decreased 17 11 same period. Desmosterol 2.5 sterol 0.2-0.3 cent. All complete between 2 5 months age; no other ‘lower phase’ lipids showed significant age. qualitatively similar those reported others, differed magnitude, more stability levels cholesterol phosphatidalethanolamine development. A sensitive indicator maturation mole galactolipid/phosphatidylcholine, which varied 1.2 2.8 maximum rate myelination occurred 20 postnatal when deposited 3.5 mg day−1 brain−1. However, this had only its eventual complement myelin. accumulation cerebroside paralleled myelin, show relationship. deposition appeared almost solely responsible continued increase weight after 100