32P INCORPORATION INTO DIFFERENT MEMBRANOUS STRUCTURES SEPARATED FROM RAT CEREBRAL CORTEX

Abstract— The time course of incorporation, between 3 hr and 16 days, of ortho[32P]phosphate into different membranous structures isolated from the rat cerebral cortex was studied. After subarachnoideal administration into the CSF it was found that myelin, mitochondria, microsomes and purified nerve‐ending membranes and synaptic vesicles incorporate 32P at the same rate. Most of the individual phospholipids of the synaptic vesicles and nerve‐ending membranes also have similar rates of incorporation. Only phosphoinositides and/or phosphatidylserine may have a more rapid metabolism. The incorporation of 32P into phosphoproteins follows a different pattern from that of the phospholipids. The intraperitoneal route is less effective in the 32P incorporation and differences among the fractions may be found. These results are discussed in relation to the problem of the blood‐brain barrier to phosphate and to the labelling of individual phospholipids in the different membranes. Copyright © 1969, Wiley Blackwell. All rights reserved