Characterization and location of secretory phospholipase A2 groups IIE, V, and X in the rat brain

Secretory phospholipases A(2) (sPLA(2)) form a diverse family of enzymes involved in a variety of physiologic and pathologic processes. Common among all sPLA(2) is the ability to cleave the second position of phospholipids, thereby releasing fatty acid and a lysophospholipid. Several sPLA(2) have been cloned and characterized in various tissues and receptors have been identified. In the nervous system, sPLA(2) groups IB, IIA, IIE, IIF, V, and XII have been identified, and binding sites for sPLA(2) have been found. Here, we report sPLA(2)-IIE and sPLA(2)-X in rat brain as well as in neurons in primary culture. We furthermore confirm the presence of sPLA(2)-V in rat brain and demonstrate the presence of sPLA(2)-V in primary neuronal cultures. The distribution of sPLA(2)-IIE, V, and -X seems to be mainly neuronal, with the highest abundance occurring in the cerebral cortex and hippocampus. We also find that sPLA(2)-IIE, -V, and -X are differentially induced by kainic acid. This study supports the concept that sPLA(2) heterogeneity in brain is functionally relevant and responsive to seizures.