A comparison of endothelium-derived relaxing factor activity in the coronary and renal arteries of the pig.

A cascade bioassay system has been used to quantify the basal and receptor-mediated endothelium-derived relaxing factor (EDRF) activity of pig coronary artery and pig renal artery. When exposed to EDRF released from a common donor vessel, pig coronary artery smooth muscle showed a greater sensitivity to EDRF than pig renal artery, and these differences were paralleled by differential responses to sodium nitroprusside. When mounted as donors in the bioassay, and EDRF detected using a common recipient, pig coronary artery and renal artery endothelium showed similar basal EDRF release rates. EDRF release in response to substance P was greater from pig coronary artery donors, but EDRF release in response to bradykinin was greater from pig renal artery donors. The data indicate that differences in EDRF response and EDRF release occur in different vessels, and that certain EDRF-releasing agents may exert regional vasodilator effects.