title: Platelet aggregation in the Asian elephant is not dependent on thromboxane B2 production.
abstract: 1. The platelet aggregation response to several known platelet agonists was evaluated in four Asian elephants. The platelets were highly responsive to stimulation with platelet-activating factor (PAF) and collagen, less responsive to adenosine diphosphate (ADP) and non-responsive to arachidonic acid, serotonin and epinephrine. 2. Arachidonic acid (1 x 10(-4) M), while inducing no aggregation, caused the release of 1248 +/- 1147 pg/ul (mean +/- SD) of thromboxane B2 (TXB2), the stable metabolite of thromboxane A2 from stimulated platelet. The addition of 1 x 10(-4) M ADP to platelets caused suboptimal aggregation and the release of only 25 +/- 10 pg TXB2/microliters. 3. The calcium channel blocker, verapamil, produced a dose-dependent inhibition of PAF-induced but not collagen-induced aggregation. The cyclooxygenase inhibitor, acetylsalicylic acid, produced no inhibition of either collagen- or PAF-induced aggregation.
authors.affiliation: Department of Biomedical Science, Ontario Veterinary College, University of Guelph, Canada.
authors.forename: P A
authors.initials: PA
authors.lastname: Gentry
authors.forename: C
authors.initials: C
authors.lastname: Niemuller
authors.forename: M L
authors.initials: ML
authors.lastname: Ross
authors.forename: R M
authors.initials: RM
authors.lastname: Liptrap
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology; D004606:Elephants / Q000097:blood*; D005260:Female; D008297:Male; D010972:Platelet Activating Factor / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D013929:Thromboxane B2 / Q000097:blood*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D001095:Arachidonic Acids; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D016718:Arachidonic Acid; D013929:Thromboxane B2; D000244:Adenosine Diphosphate; D003094:Collagen; D014700:Verapamil; D001241:Aspirin