title: Relationship between structure of phenothiazine analogues and their activity on platelet calcium fluxes.
abstract: Phenothiazine analogues have been tested for their effect on calcium uptake into platelet membrane vesicles and on ionophore-induced platelet activation, both phenomena being Ca2+-dependent. Both calcium uptake into membrane vesicles and ionophore-induced platelet activation were inhibited by the drugs. Evidence for two inhibitors as potent as chlorpromazine and trifluoperazine was found. These drugs are apparently competitive inhibitors of calcium uptake. A structure-activity relationship has been established. The data suggest that the phenothiazines are able to inhibit calmodulin-insensitive calcium uptake of platelet membrane vesicles and that therefore they cannot be assumed to be selective inhibitors of calmodulin interactions under all circumstances.
mesh_terms: D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000097:blood*; D002147:Calmodulin / Q000097:blood; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010640:Phenothiazines / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D002147:Calmodulin; D010640:Phenothiazines; D002118:Calcium