FORMATION OF PHOSPHATIDES FROM C14-LABELLED PRECURSORS IN RAT BRAIN SLICES. EFFECT OF CHLORPROMAZINE

The addition of chlorpromazine (0.1 mM) to slices of rat brain respiring in a suitable medium caused an increase in the incorporation of radioactivity from glycerol-1-C14, glycine-2-C14, and serine-3-C14 into the phospholipids of the slices. There was no increase in the incorporation of radioactivity from choline-1,2-C14 or ethanolamine-1,2-C14. Examination of the individual phosphatides showed an increase in the incorporation of radioactivity from glycerol-1-C14 into phosphatidc acid and phosphatidyl serine, with no change for lecithin and phosphatidyl ethanolamine. Higher concentrations of chlorpromazine (1.0 mM) either inhibited (glycerol-1-C14, choline-1,2-C14), did not significantly alter (glycine-2-C14, ethanolamine-1,2-C14), or stimulated (serine-3-C14) the incorporation of radioactivity into phospholipids. These results are discussed in relation to previous experiments, in which it was found that the addition of chlorpromazine (0.1 mM) to slices of guinea pig brain caused an increase in the incorporation of inorganic P32 into phosphatidic acid, phosphatidyl inositol, phosphatidyl serine, but not into lecithin or phosphatidyl ethanolamine.