Increased Breakdown of Membrane Phospholipids in Schizophrenia: Implications for the Hypofrontality Hypothesis

Abstract

Phospholipase A2 (PLA2) is a key enzyme in the metabolism of phospholipids. The extracellular PLA2 is secreted in the blood by the pancreas as a digestive enzyme (type I) or is released from activated platelets (type II). Intracellular PLA2 has been found in all cells so far investigated: the enzyme is enriched in brain membranes, where it catalyzes the hydrolysis of membrane phospholipids to release free fatty acids and cytotoxic products such as lysophosphatidylcholine. PLA2 plays an essential role in the regulation of the physicochemical properties of the neuronal membrane, which influences among others receptor function and signal transduction (for review see Farooqui et al. 1992). In brain membranes PLA2 has been found to inhibit dopamine-sensitive adenylate cyclase (Anand-Srivastava and Johnson 1981) and to decrease [3H] spiperone binding to dopamine receptors (Oliveira et al. 1984).