Different time course of atrial natriuretic factor-induced relaxation in rabbit aorta and portal vein

Atrial natriuretic factor (ANF) and nitroglycerine were tested in superfused rabbit aorta and portal vein strips precontracted with norepinephrine. The ANF dose-response curves were similar in both tissues, however, relaxation was fast and transient in portal veins whereas it was sustained and of slow onset in aortas. Nitroglycerine was more potent in portal veins than in aortas but relaxation was fast and transient in both tissues. The results suggest that the time course of ANF-induced relaxation in different vessels may be of relevance to the overall hemodynamic profile of this peptide in intact animals.