MODULATION OF PHOSPHATIDIC ACID METABOLIC PATHWAYS IN CEREBELAR NUCLEI.

GAVEGLIO VL; PASQUARÉ SJ; GIUSTO NM

San Miguel de Tucumán, Argentina

Congreso; Reunión Soc.Argenitina de Investigaciones Bioquímicas y Biología Molecular 2009; 2009

Sociedad Argentina de Investigaciones Bioquímicas y Biología Molecular

We have demonstrated the existence of lipid phosphate phosphatases (LPP), diacylglyceride lipase (DAGL) and monoacylglyceride lipase (MAGL) activities which generate second messengers implicated in intranuclear signaling. The present work evaluates the modulation of the nuclear enzymatic activities related to the metabolization of phosphatidic acid (PA). To this end, adult (4 mo) rat cerebellum was homogenized, and highly purified nuclei were isolated by sucrose-density ultracentrifugation. Nuclear preparations were checked for purity by electron microscopy and DAPI stain. Our results show that 0.2 mM triton X-100 increased monoacylglyceride (MAG) production by 219% without modifying diacylglyceride (DAG) production. However, 1 mM triton X-100 caused an increase of 100% in DAG and MAG production. Ca2+ and Mg2+ ions stimulated MAG formation by 190%. Furthermore, 50 mM NaF diminished DAG and MAG generation by a similar percentage (95%). On the other hand, vanadate decreased DAG production by 42% and produced a 30% inhibition in MAG generation. Additionally, we observed MAGL, LPA-phosphohydrolase (LPAPase) and LPA-phospholipase (LPAase) activities by using 2-arachidonoyl[3H]glycerol and 1-oleoyl[3H]-lysophosphatidic acid as substrates. These results demonstrate the presence of important signaling pathways in rat cerebelar nuclei.