Generación de diacilglicerol a través de la actividad de fosfolipasa C -fosfatidilcolina específica en sinaptosomas de corteza cerebral de rata

MATEOS, MELINA VALERIA; URANGA, ROMINA MARÍA; SALVADOR, GABRIELA ALEJANDRA; PASQUARÉ, SUSANA; GIUSTO, NORMA MARÍA

Mar del Plata, Buenos Aires, Argentina.

Congreso; XIX Reunión Anual de la Sociedad Argentina de Neuroquímica (SAN); 2004

SAN

Diacylglycerides (DAGs) are minor cell membrane components which participate not only in the regulation of membrane properties but also in several transduction pathways. DAGs with a specific fatty acid composition can be generated by the hydrolysis of several membrane phospholipids. Posphatidylcholine specific-phospholipase C (PC-PLC) is involved in several intracellular events such as the response to growth factors, proliferation, and cell death. The purpose of the present study was to study and characterize PC-PLC activity in rat cerebral cortex synaptosomes. In our experimental model, we could demonstrate for the first time the activity of an enzyme with the ability to hydrolyze PC yielding DAG. The enzyme characterization showed maximal activity at pH 7. PC-PLC activity was highly stimulated by tensioactive agents such as Triton X –100 and sodium deoxycholate and it was inhibited by milimolar calcium concentrations. In order to determine PC-PLC localization in synaptosomes, synaptosomal plasma membranes (SPM) were isolated. PC-PLC activity remained mainly in the SPM fraction, showing that PC-PLC is a membrane protein. Our results demonstrate the presence of a novel DAG generation pathway from PC in cerebral cortex synaptosomes.