title: A radioenzymatic assay to identify three groups of phospholipase A(2) in platelets.
abstract: Phospholipases A(2) (PLA(2)) are key enzymes in membrane metabolism. The release of fatty acids and lysophospholipids by PLA(2) activates several intra-cellular second messenger cascades that regulate a wide variety of physiological responses. The aim of the present study is to describe a radioenzymatic assay to determine the activity of three main PLA(2) subtypes in platelets, namely extracellular calcium-dependent PLA(2) (sPLA(2)) and intracellular calcium-dependent (cPLA(2)) and calcium-independent PLA(2) (iPLA(2)). The differentiation of these distinct PLA(2) subtypes was based on the enzyme substrate preference (arachdonic acid or palmitoyl acid) and calcium concentration. Our results indicate that this new assay is feasible, precise and specific to measure the activity of the aforementioned subtypes of PLA(2). Therefore, this protocol can be used to investigate modifications of PLA(2) homeostasis in distinct biological models addressing the pathophysiology of many medical and neuropsychiatric disorders such as schizophrenia and Alzheimer's disease.
authors.affiliation: Laboratory of Neuroscience-LIM 27, Department and Institute of Psychiatry, University of Sao Paulo, Brazil.
authors.forename: Leda L
authors.initials: LL
authors.lastname: Talib
authors.forename: Breno S
authors.initials: BS
authors.lastname: Diniz
authors.forename: Isis A
authors.initials: IA
authors.lastname: Zainaghi
authors.forename: Orestes V
authors.initials: OV
authors.lastname: Forlenza
authors.forename: Wagner F
authors.initials: WF
authors.lastname: Gattaz
mesh_terms: D001792:Blood Platelets / Q000201:enzymology* / Q000378:metabolism; D004537:Eicosanoic Acids / Q000378:metabolism; D057075:Enzyme Assays / Q000379:methods*; D005260:Female; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism; D008297:Male; D054467:Phospholipases A2 / Q000032:analysis* / Q000378:metabolism; D054512:Phospholipases A2, Calcium-Independent / Q000032:analysis / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism
chemical_list: D004537:Eicosanoic Acids; D008246:Lysophospholipids; D020033:Protein Isoforms; D054467:Phospholipases A2; D054512:Phospholipases A2, Calcium-Independent; C032881:lysophosphatidic acid; C094477:arachidic acid