THE INTERACTION OF PLATELETS WITH AORTIC SUBENDOTHELIUM - INHIBITION OF ADHESION AND SECRETION BY PROSTAGLANDIN I2

  • 1 January 1981
    • journal article
    • research article
    • Vol. 58  (2) , 198-205
Abstract
The effect of prostaglandin I2 on platelet turnover, attachment to the subendothelium and secretion following balloon deendothelialization of the rabbit aorta was studied. Survival of 51Cr-labeled platelets in the balloon-injured animals remained normal. Thirty minutes after injury, there were 4.52 .times. 106 platelets/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 [standard error of mean]) during the 1st hour after balloon injury, platelet factor 4 antigen was detected within the vessel wall by indirect immunofluorescence within 30 min of injury. An infusion of 650-850 ng/kg per min prostaglandin I2 completely inhibited platelet aggregation, and reduced surface coverage by 84% and platelet attachment by 63%. Animals given 50-100 ng/kg per 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 per min prostaglandin I2 prior to balloon injury, but sacrificed after the infusion was stopped and ex vivo platelet aggregation had returned to normal.