Thrombin receptor activating peptide-induced cellular effects: comparative studies on human platelet activation and endothelium-dependent relaxation of porcine pulmonary arteries.

Abstract

The thrombin receptor activating peptides with 6 and 14 amino acids (TRAP-6,TRAP-14) caused aggregation of washed platelets as well as of platelets in citrated and hirudin plasma. Stimulation of platelets was associated with an increase in cytosolic Ca2+ and formation of thromboxane. In porcine pulmonary arteries they induced reversible endothelium-dependent relaxation of precontracted vessels via release of endothelium-derived nitric oxide. TRAP-6 and TRAP-14 did not differ in their intrinsic activity. Both peptides possess thrombin-like activity, but their potency is more than three orders of magnitude lower than that of thrombin.