Heart is no longer considered only as an efficient pump but also as an important endocrine organ,becausre the heart generates and secretes atrial natriuretic peptide (ANP).It is well known that ANP have important biological effects,such as diuresis and natriuresis,modulating blood pressure and cardiovascular homeostasis by combining with natriuretic peptide receptors.ANP binds to NPR-A receptor which is a member of the membrane-bound guanylyl cyclase family and exerts its biological effects by increasing cGMP levels.