PHOSPHOLIPASE-A2 ACTIVITY IN SERUM OF NEUROLEPTIC-NAIVE PSYCHIATRIC-INPATIENTS

The activity of phospholipase A2 (PLA2), an enzyme that, besides a number of other functions, is involved in prostaglandin synthesis, regulation of membrane stability, and presynaptic neurotransmitter release, has been reported to be greater in the serum and plasma of schizophrenic patients than in that of other psychiatric patients and normal controls. Furthermore, it is said to be significantly reduced by haloperidol treatment. We decided to replicate these findings in an independent sample of patients by using a highly sensitive assay for determining PLA2 activity. - Methods: Of 167 consecutive male admissions giving informed consent 35 were found never to have received neuroleptics previously. Ten had DSM-III diagnoses of schizophrenia, schizophreniform disorder, or atypical psychosis, eight of other psychiatric disorders and 17 of alcohol or drug dependence (Table 1). Blood samples were drawn before medication was initiated. For patients still in hospital (Table 3), this was repeated after 21 days of treatment (n=10). Samples from 10 healthy subjects were also obtained. PLA2 activity was determined according to Marki and Franson (1986), using a radiochemical assay. - Results: On day 0, there were no statistically significant intergroup differences in PLA2 serum activity. After 21 days, it was not possible to detect any significant decrease in PLA2 activity (Table 4). The PLA2 activity of the patient groups did not differ from that of the group of healthy subjects (Table 5). - Conclusion: It was not possible to replicate the finding of increased PLA2 activity in schizophrenic patients in our sample of patients never treated with neuroleptics before. This was in spite of the fact that the radiochemical method we employed to determine PLA2 activity avoids several problems inherent in the methods used in other studies and is specially appropriate for measuring low activities of PLA2. There was no evidence to support the notion of PLA2 as a specific marker for types of schizophrenia.