MAO inhibitory side effects of neuroleptics and platelet serotonin content in schizophrenic patients.

In order to study the putative monoamine oxidase (MAO) inhibitory side effect of neuroleptics and simultaneous changes in platelet serotonin content both MAO-B activity and serotonin (5-HT) content in platelets of 30 healthy volunteers and 50 schizophrenic patients treated with neuroleptics were investigated. Our results have shown significantly lower MAO-B activity (15.26 +/- 6.81 S.D. vs. 8.63 +/- 3.82 mmol/hour/10(9) platelets) and higher platelet 5-HT content (906.19 +/- 285.33 vs. 1,727.85 +/- 947.40 ng/10(9) platelets) in the schizophrenic group. Platelet MAO-B activity was considerably lower in paranoid and residual schizophrenics compared with other patients, however, no difference was found in platelet 5-HT content between different subtypes of schizophrenia. Various neuroleptic treatments did not produce different effects either on platelet serotonin content or platelet MAO-B activity.