Diacylglicerol generation by phosphatidylcholine breakdown catalyzed by a phospholipase C from central nervous system

MATEOS, MELINA; URANGA, ROMINA; SALVADOR, GABRIELA; GIUSTO, NORMA

Pinamar, Buenos Aires, Argentina.

Congreso; 10th Congress PABMB, 41st Annual Meeting SAIB and 20th Annual Meeting SAN.; 2005

SAN, SAIB, PABMS

Diacylglycerol (DAG) derived from phosphatidylcholine (PC) acts as a lipid second messenger and it can be generated by the activation of phospholipase D (PLD) and phosphatidic acid phosphohydrolase type 2 (PAP2) pathway or by a phosphatidylcholine-specific phospholipase C (PC-PLC). Previously we had demonstrated the PC-PLC pathway in rat cerebral cortex synaptosomes (CC Syn). Our purpose was to characterize PC-PLC activity in central nervous system. Ethanol (a PLD activity marker) and D609 (a selective PC-PLC inhibitor) decreased DAG generation by 42% and 61%, respectively at 20 min incubation. These data demonstrate that both PLD/PAP2 pathway and PC-PLC contribute to DAG generation in CC Syn. It was also demonstrated that PC-PLC activity remained located mainly in the synaptosomal plasma membrane fraction. Western blot analysis with anti PC-PLC antibody showed a band of 66 kDa in CC Syn. In prelabeled synaptosomes with [3H]glycerol DAG generation was stimulated by glutamate (5 mM). Our results indicate the presence of a novel DAG–generating pathway in CC synaptosomes, and its probable participation in oxidative processes induced by high glutamate concentrations.