title: Failure of clinical concentrations of halothane to block adenosine diphosphate-induced platelet aggregation in vitro.
abstract: A dose-related inhibition by halothane of adenosine diphosphate-induced platelet aggregation was measured for human platelets in plasma anticoagulated with sodium citrate 6.8 mmol litre-1 or 13.6 mmol litre-1, or heparin 2 u. ml-1 and for platelets separated from plasma by albumin density gradient centrifugation and requiring no anticoagulant. By maintaining exposure and assay temperature at 37 degrees C, maintaining physiological pH, avoiding age-related deterioration and using an atraumatic equilibration method, no inhibition was found at clinical concentrations of halothane and 50% inhibition required greater than halothane 10%. Sodium citrate, a calcium chelating anticoagulant, was found to enhance halothane inhibition.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology*; D002951:Citrates / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006221:Halothane / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D013997:Time Factors
chemical_list: D002951:Citrates; D000244:Adenosine Diphosphate; D006221:Halothane