Interactions of prostanoids with the platelet activating factors.
The platelet-activating factor (PAF) induced a marked increase of the thromboxane (TX) B2-formation in the incubation medium of isolated myocardium and tissue from other organs. The content of the 6-oxo-prostaglandin (PG)F1 alpha, the inactive metabolite of PGI2, remained uninfluenced or showed a small decrease. PAF, given in a concentration of 2.10(-9) mol/l or a single dose of 100 ng, significantly reduced the contraction force and the coronary flow of isolated guinea-pig hearts. This effect was connected with a high efflux of TXA2. The PAF-antagonist, WEB 2086, nearly abolished the cardiac effects of PAF, and iloprost or a pretreatment with indomethacin markedly reduced the PAF-influence on the heart. The TXA2-antagonist BM 13177 was ineffective. The results indicate a close interaction between the myocardial PAF-effect and the TXA2-formation of the heart tissue, but gave no suggestion for a mediation of the PAF-effect by TXA2. The PAF-antagonistic action of WEB 2086, iloprost and indomethacin could be of some interest in the therapy of cardiovasculatory diseases.
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology; D016285:Iloprost / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D010477:Perfusion; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000502:physiology; D011453:Prostaglandins / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology; D013928:Thromboxane A2 / Q000037:antagonists & inhibitors; D013929:Thromboxane B2 / Q000096:biosynthesis; D014230:Triazoles / Q000494:pharmacology
D001381:Azepines; D010972:Platelet Activating Factor; D011453:Prostaglandins; D013449:Sulfonamides; D014230:Triazoles; C052518:WEB 2086; D013929:Thromboxane B2; D013928:Thromboxane A2; D015121:6-Ketoprostaglandin F1 alpha; C040624:sulotroban; D016285:Iloprost; D007213:Indomethacin