title: Impact of clozapine, N-desmethylclozapine and chlorpromazine on thromboxane production in vitro.
abstract: Thromboxane A2 (TxA2) and the activation of its receptor have been shown to modulate vasoconstriction and platelet aggregation as well as dopaminergic and serotonergic signalling. Dopaminergic and serotonergic systems play a crucial role in the pathophysiology of schizophrenia and these systems are the main targets of antipsychotics (APs). As the first antipsychotic (AP) chlorpromazine (CPZ) has already been shown to reduce TxA2, we hypothesized that the AP clozapine and its metabolite N-desmethylclozapine (NDMC) might also influence TxA2 production. We measured levels of thromboxane B2 (TxB2), the metabolite of the very unstable molecule TxA2, in unstimulated and stimulated blood samples of 10 healthy female subjects in a whole blood assay using toxic shock syndrome toxin-1 (TSST-1) and monoclonal antibody against surface antigen CD3 combined with protein CD40 (OKT3/CD40) as stimulants. Blood was supplemented with the APs CPZ, clozapine or NDMC in one of four different concentrations. Additionally, thromboxane levels were measured in blood without the addition of APs under different stimulation conditions. Under TSST-1 as well as OKT3/CD40 stimulation, mean TxB2 concentrations were significantly (p < 0.05) decreased by clozapine over all applied concentrations. NDMC led to a decrease in TxB2 levels under unstimulated conditions as well as under TSST-1 stimulation. CPZ reduced TxB2 production at low concentrations under unstimulated and TSST-1- stimulated conditions. Clozapine, NDMC and CPZ possibly act on neurotransmitter systems via modulation of TxA2 or TxB2 production. Additionally, known side effects of APs such as orthostatic hypotension may be a result of changes in the concentrations of TxA2 or TxB2.
authors: Department of Psychiatry, University of Leipzig, Leipzig, Germany. Hubertus.Himmerich@medizin.uni-leipzig.de
authors: Hubertus
authors: H
authors: Himmerich
authors: Luise
authors: L
authors: Schmidt
authors: Susen
authors: S
authors: Becker
authors: Linda
authors: L
authors: Kortz
authors: Jeremias
authors: J
authors: Schonherr
authors: Roland
authors: R
authors: Mergl
authors: Katrin
authors: K
authors: Bauer
authors: Ulrich
authors: U
authors: Sack
authors: Abigail J
authors: AJ
authors: Sheldrick
authors: Joachim
authors: J
authors: Thiery
authors: Uta
authors: U
authors: Ceglarek
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology*; D002746:Chlorpromazine / Q000494:pharmacology*; D003024:Clozapine / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D006801:Humans; D008875:Middle Aged; D013928:Thromboxane A2 / Q000096:biosynthesis* / Q000097:blood; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; C058272:norclozapine; D013928:Thromboxane A2; D003024:Clozapine; D002746:Chlorpromazine