Stored in secretory granules of atrial granular cells and released into hemolymph after electrostimulation of the heart nerve. Highly expressed in atrium. Moderately expressed in the pericardium, pulmonary vein, nephridium, arteria anterior, ovotestis and connective tissue. Low expression found in intestine, lung plexus, diaphragm, subesophageal ganglion, ventricle and digestive gland. Very low expression found in columellar retractor, pedal nerves and cerebral ganglion. Not expressed in hemocytes. Expressed in newborn snails as well as adults. N-glycosylated. Non-glycosylated.