Age-associated changes in the lipid composition of synaptic membrane rafts

MATEOS MV; ORESTI GM; FURLAND NE; SALVADOR GA; GIUSTO NM

San Miguel de Tucumán, Argentina

Congreso; XLV Reunión Nacional de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2009

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Membrane rafts act as signal transduction platforms in many physiological processes. In this study we determined the lipid composition of cerebral cortex synaptic membrane rafts (SMR) obtained from adult (4 month old) and aged (28 month old) rats. SMR showed an enrichment in cholesterol and sphingomyelin (SM) content with respect to isolated synaptic endings (Syn). Additionally, SM content increased by 36% in SMR obtained from aged animals with respect to adults. Both SMR preparations showed an enrichment in phosphatidylcholine (PC), and a decrease in phosphatidylethanolamine and phosphatidylserine content (by 28%, 25% and 25% respectively) with respect to Syn. Moreover, total phospholipid-fatty acid composition from SMR presented an increase in 16:0 (35%), and a decrease in 20:4n-6 (67%) and 22:6n-3 (68%) content in adults. The most striking changes in fatty acid composition were mainly due to changes in PC.  Similar changes in fatty acid composition were observed between SMR and Syn obtained from aged rats. Nevertheless, the 20:4n-6 and 22:6n-3 content significantly decreased (80%) with respect to SMR from adults. SMR displayed a more saturated fatty acid composition than Syn and this effect was even more pronounced in aged animals. Our results suggest that the distinct fatty acyl composition in SMR could be responsible for the signaling impairment observed in nervous system during aging.