Brachial Artery t-PA Release in Heart Transplant Recipients

Bradykinin stimulates t-PA release from intact vessels, but not from endothelial cells in culture. It has been proposed that the nerves of blood vessels are the source of bradykinin stimulated t-PA release. In order tho test this hypothesis, we intend to infuse bradykinin into the brachial (arm) artery and the coronary arteries of heart transplant recipients and control subjects. This is because heart transplant recipients do not have nerves to their coronary arteries. This protocol studies the effects of bradykinin on t-PA release in the forearm of transplant recipients. The brachial artery has intact nerves. Separate protocols address coronary artery infusions in healthy subjects and transplant recipients and forearm infusions in healthy subjects.