title: Effects of ketanserin, a selective 5-HT2 serotonergic antagonist, on the secondary recruitment of human platelets in vitro.
abstract: Ketanserin, a selective 5-HT2 serotonergic receptor antagonist, reduces in vitro the release-associated human platelet aggregation induced by threshold concentrations of collagen and curtails the second wave of aggregation/release induced by critical concentrations of ADP in particular and, to a lesser extent, of 1-epinephrine. Its inhibitory effect on the second waves becomes more pronounced when the reaction is already attenuated by moderate cyclo-oxygenase inhibition with esculetin, by yohimbine or by propranolol. The first wave of aggregation induced by ADP or 1-epinephrine is not affected. Such an inhibition of secondary platelet recruitment by ketanserin in vitro may be due to an inhibition of the 5-HT2 receptor-mediated amplifying effects of platelet-released 5-HT or to a non-specific interference with the platelet membrane, reducing the release of mediators from the platelets. Reduction of the increased plasma BTG levels in patients after ketanserin may result from such release-inhibiting mechanisms.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000097:blood; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D007650:Ketanserin; D007700:Kinetics; D010880:Piperidines / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000097:blood; D012702:Serotonin Antagonists / Q000494:pharmacology*
chemical_list: D010880:Piperidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D003094:Collagen; D007650:Ketanserin; D004837:Epinephrine