INCREASED PLATELET PHOSPHOLIPASE A(2) ACTIVITY IN SCHIZOPHRENIA

The intracellular enzyme phospholipase A(2) (PLA(2)) plays an essential role in the breakdown of membrane phospholipids, which regulate the physicochemical properties of the cell membrane. In the brain PLA(2) has been reported to influence receptor function and signal transduction. Regarding dopaminergic neurons, data from animal experiments and from binding studies suggest that PLA(2) activation reduces dopaminergic neurotransmission. In the present study we investigated intracellular PLA(2) in platelets from 31 DSM-III-R paranoid schizophrenic patients (15 neuroleptic-naive) compared to 31 healthy individuals and to 31 non-schizophrenic psychiatric controls, both matched to the schizophrenics by age and sex. Platelet PLA(2) activity was significantly increased in schizophrenics as compared to healthy and to psychiatric controls. Neuroleptic treatment reduced significantly the enzyme activity. Our findings in platelets suggest an accelerated breakdown of membrane phospholipids in schizophrenia. An accelerated phospholipid breakdown has also been reported in the frontal cortex from schizophrenic patients. Further studies should clarify whether increased PLA(2) in the brain, as observed in platelets, could contribute to a frontal dysfunction in schizophrenia.