title: The interaction of platelets with aortic subendothelium: inhibition of adhesion and secretion by prostaglandin I2.
abstract: We have studied the effect of prostaglandin I2 on platelet turnover, attachment to the subendothelium, and secretion following balloon deendothelialization of the rabbit aorta. Survival of 51Cr-labeled platelets in the balloon-injured animals remained normal. Thirty minutes after injury, there were 4.52 X 10(6) platelets/sq cm attached to the aortic surface, which was 87% covered by platelets. Although plasma platelet factor 4, as measured by radioimmunoassay, did not rise above the normal level of 6.8 +/- 2.6 ng/ml (mean +/- SEM) during the first hour after balloon injury, platelet factor 4 antigen was detected within the vessel wall by direct immunofluorescence within 30 min of injury. An infusion of 650-850 ng/kg/min prostaglandin I2 completely inhibited platelet aggregation and reduced surface coverage by 84% and platelet attachment by 63%. Animals given 50-100 ng/kg/min prostaglandin I2, which only partially inhibited platelet aggregation, had 70% of the aortic surface covered by platelets. Platelet factor 4 antigen was also detected within the aortic wall. Platelet attachment was normal in animals that had been given 850 ng/kg/min prostaglandin I2 prior to balloon injury but sacrificed after the infusion was stopped and ex vivo platelet aggregation had returned to normal.
mesh_terms: D000818:Animals; D001011:Aorta / Q000293:injuries / Q000473:pathology* / Q000648:ultrastructure; D001792:Blood Platelets / Q000378:metabolism; D002448:Cell Adhesion; D002470:Cell Survival; D004727:Endothelium / Q000473:pathology; D011464:Epoprostenol / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D007700:Kinetics; D008297:Male; D010978:Platelet Factor 4 / Q000276:immunology; D011453:Prostaglandins / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D011453:Prostaglandins; D010978:Platelet Factor 4; D011464:Epoprostenol