Genes encoding multiple forms of phospholipase A2 are expressed in rat brain

The polymerase chain reaction was utilized to determine which of six cloned phospholipase A2 (PLA2) messenger RNAs (mRNAs), encoding four distinct low molecular weight forms of secretory PLA2 (PLA2-IB, PLA2-IIA, PLA2-IIC and PLA2-V), a calcium-dependent high molecular weight PLA2 (PLA2-IV, cPLA2) and a calcium-independent high molecular weight PLA2 (PLA2-VI, iPLA2), were expressed in different regions of rat brain and in a number of peripheral tissues. Pancreatic PLA2-IB mRNA was not expressed in the brain. PLA2-IIA, PLA2-IV and PLA2-VI mRNAs appeared to be ubiquitously expressed in brain, with relatively similar levels detected in all regions. PLA2-IIC mRNA was expressed in all brain regions but not in any of the peripheral tissues studied. PLA2-V mRNA was found at low levels in most areas of the brain, but at very high levels in the hippocampus. These results indicate that mammalian brain has the potential to express multiple isoforms of PLA2 which could be important given the potential role of these enzyme activities in ischaemic damage and in the regulation of synaptic plasticity.