Expression and induction of secretory phospholipase A2 group IB in brain.

Secretory phospholipases A2 (sPLA2) form a diverse family of enzymes involved in physiologic and pathologic processes. Common among all sPLA2 is the ability to cleave acyl groups of phospholipids at C2 of the glycerol backbone, thereby releasing fatty acid and a lysophospholipid. Several sPLA2 have been cloned and characterized in various tissues. Furthermore, receptors have been identified. In the nervous system sPLA2 groups IIA, IIE, IIF, V, and XII have been identified, and binding sites for sPLA2 group IB (sPLA2-IB) have been found. Here, we report sPLA2-IB in rat and human brain as well as in neurons in primary culture. The distribution of sPLA2-IB seems to be mainly neuronal, with the highest abundance occurring in the cerebral cortex and hippocampus. We also find that genes encoding sPLA2-IB are induced by kainic acid and by electroshock-induced convulsions. Based on the present results we suggest that sPLA2-IB may be a neuronal intercellular signalling modulator.