Fibrin(ogen)-derived peptide Bβ 30–43 increases coronary blood flow in the anesthetized dog

The hemodynamic effects of intracoronary administration of a fibrin (ogen)-derived peptide Bβ 30–43 (Arg-Pro-Ala-Pro-Pro-Pro-Ile-Ser-Gly-Gly-Gly-Tyr-Arg-Ala) were evaluated in open-chest anesthetized dogs. Coronary blood flow (CBF) increased and coronary vascular resistance (CVR) decreased with intracoronary administration of peptide Bβ 30–43. These changes were dependent on the amount of the peptide Bβ 30–43 administered. There were no significant effects of peptide Bβ 30–43 on aortic & left ventricular end-diastolic pressures. Plasma 6-keto-PGFl a (stable hydrolysis product of PGI 2) concentrations increased in coronary sinus blood samples in conjunction with increase in CBF. Intravenous administration of indomethacin (5 mg/kg) inhibited the release of PGI2and almost completely abolished the effects of the fibrin(ogen)-derived peptide on CBF. This study suggests that this fibrin (ogen)-derived peptide has potent effects on the coronary vascular bed of the dog, and that these effects are in large part mediated through PGI 2release. These coronary hemodynamic effects of fibrin(ogen)-derived products may have important autoregulatory effects in atheromatous coronary circulation, wherein thrombi may form spontaneously.