Phosphatidic acid metabolization in the presence of lysophosphatidic acid (LPA), ceramide 1 phosphate (C-1-P) and sphingosine 1 phosphate (S-1-P) in cerebral cortex synaptosomes from adult and aged rats

PASQUARE, SUSANA; SALVADOR, GABRIELA; GIUSTO, NORMA

Pinamar

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

Sociedad Argentina de investigación en bioquimica y Biología Molecular

PHOSPHATIDIC ACID METABOLIZATION IN THE PRESENCE OF LYSOPHOSPHATIDIC ACID (LPA), CERAMIDE 1 PHOSPHATE (C-1-P) AND SPHINGOSINE 1 PHOSPHATE (S-1-P) IN CEREBRAL CORTEX SYNAPTOSOMES FROM ADULT AND AGED RATS. Pasquaré, Susana J; Salvador, Gabriela A and Giusto,Norma M. Instituto de Investigaciones Bioquímicas, B8000 FWB Bahía Blanca, Argentina.E-mail:pasquare@criba.edu.ar    We have reported the presence of phosphatidate phosphohydrolase, PAP2 isoform and the stimulation by aging of this activity in synaptosomes. PAP2 hydrolyzed not only phosphatidic acid (PA) but also other phosphorylated substrates such as LPA, C-1-P y S-1-P producing different intracellular mediators. The purpose of this work was to evaluated in synaptosomes the preference for the isoform of PAP2 by different concentrations of the alternative substrates and to analyzed the aging effect. Synaptosomes were prepared from adult (3 mo) and aged (26 mo) rats cerebral cortex. PAP2 was assayed using [3H] PA as substrate. Diacylglycerol formed by PAP2 action was partially metabolized to monoacylglycerol and glycerol. The presence of PAP2b was observed by Western Blot. PAP2 from adult membranes diminished its activity by 20%, 36% and 14% with LPA, C-1-P and S-1-P, respectively. In aged membranes was observed a major competitive effect in the presence of C-1-P and S1P. A differential relation between DAG, MAG and glycerol was observed in the presence of the substrates. Our results are indicative of a differential preference of PAP2 by its alternative substrates in aged membranes respect to adult membranes.