Platelet aggregation induced by ether-linked phospholipids. 1. Inhibitory actions of bovine serum albumin and structural analogues of platelet activating factor.
Ether-linked lysophosphatidic acid was able to induce aggregation of platelets from various animals. Feline platelets were the most sensitive followed in decreasing order by human, bovine and rabbit platelets. ONO-6240 and CV-3988, which are antagonists of platelet activating factor, did not inhibit aggregation of feline platelets induced by ether-linked lysophosphatidic acid, indicating that the aggregation induced by the lysophosphatidic acid did not involve receptors for platelet activating factor. An addition of bovine serum albumin caused dose-dependent inhibitions on the aggregation of platelets by both ether-linked lysophosphatidic acid and platelet activating factor. Moreover, 0.5% bovine serum albumin reversed platelet aggregation by the active phospholipid before this aggregation reached a maximum. These results suggest that the lysophosphatidic acid exerts its stimulatory action extracellularly, probably by interacting with specific sites on the surface of platelet.
D000818:Animals; D002415:Cats; D002417:Cattle; D004987:Ethers; D006801:Humans; D008246:Lysophospholipids; D010712:Phosphatidic Acids / Q000494:pharmacology*; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D011817:Rabbits; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000494:pharmacology
D004987:Ethers; D008246:Lysophospholipids; D010712:Phosphatidic Acids; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor; D013844:Thiazoles; D012710:Serum Albumin, Bovine; C037913:CV 3988; C048549:ONO 6240