Endothelin does not affect aggregation of human platelets.
Endothelin (ET-1) is a recently discovered endothelial-derived peptide with pronounced vasoconstrictor activity. The present study addressed whether ET-1, in analogy with several other vasoactive agents, can induce or modulate aggregation of human platelets in vitro. Venous blood from healthy donors was collected in citrate or heparin and platelet-rich plasma (PRP) was prepared. Portions of the PRP were added to drugs, and platelet aggregation was recorded according to Born & Cross (1963). ET-1 added to the PRP (final concentrations 1-100 nM) did not induce aggregation of platelets, either in citrate- or heparin-containing plasma. Adenosine-diphosphate (0.5-2 microM) or thrombin (0.1-0.4 NIH units ml-1) induced dose-dependent aggregation of platelets in citrate- or heparin-containing PRP; such aggregation was, however, not affected by ET-1 (1-100 microM) either. We conclude that ET-1, in contrast to other endothelial-derived vasoactive agents, lacks direct effect on platelet aggregation in vitro.
Edlund
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Department of Clinical Physiology, Huddinge Hospital, Sweden.
Wennmalm
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D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000863:Antacids / Q000494:pharmacology; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D016232:Endothelins / Q000494:pharmacology*; D005260:Female; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D013917:Thrombin / Q000494:pharmacology
D000863:Antacids; D002951:Citrates; D016232:Endothelins; D019343:Citric Acid; D000244:Adenosine Diphosphate; D006493:Heparin; D013917:Thrombin