title: Effects of neuroleptics on platelet monoamine oxidase activity.
abstract: Platelet MAO activity in schizophrenics was significantly decreased, by about 15%, after 3 weeks of treatment with haloperidol. Treatment with thioridazine or butaperazine also tended to decrease platelet MAO activity. The neuroleptic-induced decrease began to appear within a few days of treatment and did not show tolerance over 1-2 months of treatment with haloperidol. Platelet MAO activity of schizophrenic patients measured during drug-free base-line was not significantly different from that of normal controls, but MAO activity of schizophrenics was significantly lower than normals after 3 weeks of treatment with neuroleptics. The extent of decrease in platelet MAO activity correlated negatively with base-line prolactin and its increase after 24 hr. With PEA as substrate, the decrease in activity correlated positively with steady state plasma haloperidol.
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001792:Blood Platelets / Q000201:enzymology*; D006220:Haloperidol / Q000627:therapeutic use; D006801:Humans; D008995:Monoamine Oxidase / Q000097:blood*; D010640:Phenothiazines / Q000627:therapeutic use; D011388:Prolactin / Q000097:blood; D011618:Psychotic Disorders / Q000188:drug therapy / Q000201:enzymology*; D012559:Schizophrenia / Q000188:drug therapy / Q000201:enzymology*; D013881:Thioridazine / Q000627:therapeutic use
chemical_list: D014150:Antipsychotic Agents; D010640:Phenothiazines; D011388:Prolactin; D008995:Monoamine Oxidase; D006220:Haloperidol; D013881:Thioridazine