title: The effects of some beta lactam antibiotics on (3H)-methyl-yohimbine binding to intact human platelets.
abstract: Several antibiotics have been reported to cause a bleeding diathesis in man, characterized by reduced platelet aggregation. We investigated the effects of several of the penicillins and of moxalactam on the binding of (3H)-methyl-yohimbine to intact human platelets. The (3H)-methyl-yohimbine binding met the criteria for interaction at an alpha2 adrenergic binding site and showed low interindividual variability. Penicillin G, ticarcillin, carbenicillin, piperacillin and moxalactam all inhibited (3H)-methyl-yohimbine binding, but at concentrations far in excess of clinically achievable plasma levels. We conclude that these compounds exert their antiplatelet effects by a mechanism other than competitive inhibition of catecholamine binding.
authors.forename: S E
authors.initials: SE
authors.lastname: Borst
authors.forename: K K
authors.initials: KK
authors.lastname: Hui
authors.forename: M E
authors.initials: ME
authors.lastname: Conolly
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001667:Binding, Competitive; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D004088:Dihydroergotoxine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D014316:Tritium; D015016:Yohimbine / Q000031:analogs & derivatives* / Q000378:metabolism; D047090:beta-Lactams
chemical_list: D000317:Adrenergic alpha-Antagonists; D000900:Anti-Bacterial Agents; D011942:Receptors, Adrenergic, alpha; D047090:beta-Lactams; D014316:Tritium; D004088:Dihydroergotoxine; D015016:Yohimbine; C046153:1-methylyohimbine