REGIONAL DISTRIBUTION OF PHOSPHOLIPIDS AND POLYPHOSPHATIDYL INOSITIDES IN THE RABBITS SPINAL-CORD

The plasticity of the membrane phospholipids in general and stimulated phosphoinositides turnover in particular are the subjects in a variet y of neural paradigms studying the molecular mechanisms of neuronal ch anges under normal and pathological conditions. The regional modifiabi lity of phospholipids (SM, PC, PS, PI, PA + DG, PE), polyphosphatidyli nositides (PI, PIP, PIP2) and diacylglycerol-dependent incorporation o f CDP-choline into phosphatidylcholine in the gray matter, white matte r, dorsal hems, intermediate zone and ventral hems of the rabbit's spi nal cord was studied. We have found 1. a significant increase in the c oncentration of SM, PC, PS, DG + PA and PE in the white matter in comp arison to the gray one, 2. the highest concentration of the outer memb rane leaflet-bound phospholipids in the dorsal hems and the inner memb rane phospholipids in the intermediate zone in comparison to the gray matter, 3. a substantial amount of labeled polyphosphatidylinositides (poly-PIs) in the spinal cord white matter with descending order PIP > PI > PIP2, 4. similar incorporation of myo-2-[H-3]inositol into all p oly-PIs in ventral hems and intermediate zone, but a different, lower incorporation into PI and PIP and higher into PIP, in the dorsal horns , 5. higher diacylglycerol-dependent incorporation of CDP-choline into PC in the regionally undivided gray matter than in the white matter t aken as a whole, 6. the high proportion of diacylglycerol-dependent in corporation of CDP-choline into PC in both the ventral and dorsal hems , whereas that in the intermediate zone remained low.