title: Platelet-mediated vascular contractions: inhibition of the serotonergic component by ketanserin.
abstract: In vitro stimulation of washed rat platelets (2.5 X  10(10)/1) with thrombin (0.002 U/1) as well as their activation on de-endothelialized vascular preparations, produced a strong contraction of isolated rat caudal arteries. Pharmacodissection and specific measurements of various mediators (5-hydroxytryptamine, thromboxane B2, ATP) showed the platelet-mediated contraction to be mainly mediated by 5-hydroxytryptamine, either by its direct effect or through amplification of prostaglandin-effects at the level of the vessel or the platelets. Platelet-mediated vasospastic episodes were effectively reduced by ketanserin, a selective 5-HT2 receptor antagonist.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood; D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure; D003864:Depression, Chemical; D007650:Ketanserin; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000648:ultrastructure; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012702:Serotonin Antagonists / Q000494:pharmacology; D013496:Suprofen / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology
chemical_list: D001095:Arachidonic Acids; D010880:Piperidines; D012702:Serotonin Antagonists; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D007650:Ketanserin; D013496:Suprofen; D013917:Thrombin