title: Substrate-typic changes of platelet monoamine oxidase activity in sub-types of schizophrenia.
abstract: Monoamine oxidase (MAO) activity has been measured in the platelets of controls (n = 42) and schizophrenic patients (n = 49) of three subtypes, using beta-phenylethylamine, p-tyramine, and tryptamine as substrates. Characteristic differences of MAO activity were observed between platelets of patients and controls; the differences were substrate-typic: decreased enzyme activity was found with all three substrates in platelets of the parnaoid subtype. With tryptamine, MAO activity was decreased in the platelets of all three sub-types of schizophrenia. With p-tyramine, MAO was low in patients with affective psychoses and paranoid schizophrenia. The value of MAO activity measurements as a means for distinguishing sub-types of schizophrenic disorders is improved by using two substrates; tryptamine and p-tyramine. Possible mechanisms of the substrate-typic changes of platelet MAO activity in schizophrenia are discussed.
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000201:enzymology; D001792:Blood Platelets / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000097:blood*; D010627:Phenethylamines; D012557:Schizoid Personality Disorder / Q000201:enzymology; D012559:Schizophrenia / Q000201:enzymology*; D012563:Schizophrenia, Paranoid / Q000201:enzymology; D014363:Tryptamines; D014439:Tyramine
chemical_list: D010627:Phenethylamines; D014363:Tryptamines; D008995:Monoamine Oxidase; D014439:Tyramine