Effects of prostacyclin on platelet aggregation as studied with "filter-loop" technique in the flowing blood of the dog.
Using Hornstra's "filter loop" technique for determination of platelet aggregation in the circulating blood, the role played by prostaglandin I2 (PGI2) in platelet aggregation was studied in the canine heart-lung preparation (HLP) supported by a donor. A dose-related aggregation of platelet was induced by close injection of ADP into the "filter loop". PGI2 induced a marked suppression of ADP-induced platelet aggregation. After indomethacin, ADP-induced platelet aggregation became very much protracted, but was promptly terminated by PGI2. Bradykinin produced an inhibition of platelet aggregation, while it produced an increase in the coronary blood flow (CBF). After indomethacin, the increase in CBF and the inhibition of ADP-induced platelet aggregation produced by bradykinin was greatly attenuated. Essentially similar results were obtained in the anesthetized closed-chest dogs. These findings strongly suggest that the transient nature of ADP-induced platelet aggregation in the flowing blood is due to the intervention of antiaggregatory PGI2.
D000244:Adenosine Diphosphate / Q000008:administration & dosage; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D011464:Epoprostenol / Q000494:pharmacology*; D005260:Female; D005374:Filtration; D006339:Heart Rate; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D011312:Pressure; D011453:Prostaglandins / Q000494:pharmacology*
D011453:Prostaglandins; D000244:Adenosine Diphosphate; D011464:Epoprostenol; D001920:Bradykinin; D007213:Indomethacin