Heterogeneity in vasorelaxant effects of alpha-human atrial natriuretic polypeptide in the dog

Effects of alpha-human natriuretic polypeptide (ANP) on isolated canine vascular strips were examined in 6 arteries and 5 veins. Under the preconstriction with either methoxamine, prostaglandin F2 alpha or KCl, ANP relaxed the vascular strips to various degrees, depending on the region removed from the circulatory system. The largest relaxation was obtained in the pulmonary artery, suggesting that the pulmonary artery may be an important site of action of ANP.