atrial natriuretic peptide receptor atrial natriuretic peptide receptor an atrial natriuretic peptide receptor is a receptor for atrial natriuretic peptide. mechanism npra and nprb are linked to guanylyl cyclases, while nprc is g-protein-linked and is a "clearance receptor" that acts to internalise and destroy the ligand. anp activation of the anp catalytic receptor will stimulate its intracellular guanylyl cyclase activity to convert gtp to cgmp. cgmp will then stimulate cgmp-dependent protein kinase (pkg), which will then induce smooth muscle relaxation. this is particularly important in the vasculature, where vascular smooth muscle will bind anp released as a result of increasing right atrial pressure and will cause the walls of the vasculature to relax. this relaxation will decrease total peripheral resistance, which will in turn decrease venous return to the heart. the decrease in venous return to the heart will reduce the preload and will result in the heart's having to do less work. there is also a soluble guanylyl cyclase that cannot be stimulated by anp. instead, vascular endothelial cells will use l-arginine to make nitric oxide via nitric oxide synthase. the nitric oxide will then diffuse into the vascular smooth muscle and will activate the soluble guanylyl cyclase. the subsequent increase in cgmp will cause vasodilation with the same effects as described above. this is why nitroglycerine is given to a person having a heart attack. the nitroglycerine will be metabolized to nitric oxide, which will stimulate soluble guanylyl cyclase. this will result in a decrease in total peripheral resistance and a decrease in preload on the heart. as a result, work done by the heart will decrease and will allow the heart to contract less strongly. weaker contractions will lead to more blood flow in the coronary arteries, which will help the ischemic cardiac myocytes. types there are three distinct atrial natriuretic factor receptors identified so far in mammals: natriuretic peptide receptors 1, 2, and 3. natriuretic peptide receptor a/ guanylate cyclase a (atrionatriuretic peptide receptor a)identifierssymbolnpr1alt. symbolsanpra, nprancbi gene4881hgnc7943omim108960refseqnm_000906uniprotp16066other datalocuschr. 1 q21-q22search forstructuresswiss-modeldomainsinterpro natriuretic peptide receptor b/ guanylate cyclase b (atrionatriuretic peptide receptor b)identifierssymbolnpr2alt. symbolsanprb, nprbncbi gene4882hgnc7944omim108961refseqnm_003995uniprotp20594other datalocuschr. 9 p21-p12search forstructuresswiss-modeldomainsinterpro natriuretic peptide receptor c/ guanylate cyclase c (atrionatriuretic peptide receptor c)identifierssymbolnpr3alt. symbolsanprc, nprcncbi gene4883hgnc7945omim108962refseqnm_000908uniprotp17342other datalocuschr. 5 p14-p1search forstructuresswiss-modeldomainsinterpro