Pharmacology and receptor binding of atrial natriuretic factor in vascular smooth muscle

Characterization of the vascular pharmacology and receptor binding of atrial natriuretic factor (ANF) has been achieved utilizing a synthetic peptide which contains the sequence and biological activity of ANF. The synthetic ANF (sANF) relaxes aortic segments contracted by agonists or by low (15 to 20 mM) but not high (greater than or equal to 40 mM) concentrations of K+. The relaxation to sANF is well maintained, reversible, independent of the vascular endothelium and correlated with increases in cyclic GMP (with no change in cyclic AMP). Plasma membranes prepared from rabbit aorta and kidney possess high affinity (Kd = 100 pM) specific binding sites for sANF. An excellent correlation exists between the receptor binding and pharmacology for several synthetic analogs of ANF. The presence of these receptors appears consistent with the activation of particulate (but not soluble) guanylate cyclase by sANF. sANF does exhibit a profound regional vasodilator selectivity which can be explained, in part, by changes in receptor density.