Effect of aspirin on local prostaglandin production and serotonin accumulation in a canine model with coronary cyclic flow variations or thrombosis

We have reported that thromboxane A 2 and serotonin are two important mediators of coronary cyclic flow variations (CFVs) caused by recurrent platelet aggregation and dislodgement on a stenosed coronary arterial wall with endothelial injury. To test the hypothesis that blocking the synthesis of thromboxane A 2 would not prevent serotonin release, 1.1, 4.6, and 9.2 mg/kg of aspirin were administered through the left atrium to 27 dogs with CFVs. The CFV elimination rate was 70% in the aspirin-treated dogs. Thromboxane B 2 and serotonin concentrations were measured in different coronary arterial segments. There were significantly lower thromboxane B 2 and 6-keto-PFG 1a levels in the stenosed left arterior descending (LAD) segments with increasing dosage of aspirin-208 ± 36, 24 ± 31, 50 ± 6 ng/g ( P