Atrial Natriuretic Peptide Regulation of Vertebrate Intestinal Ion Transport

Atrial natriuretic peptide (ANP), in spite of its name, is synthesizedand secreted in vertebrates by both the atria and the ventriclesand also a number of extracardiac tissues. Likewise, the listof putative targets of ANP is large and includes, in additionto the kidney and vascular smooth muscle, the ion- and water-transportingintestine. Immunohistochemical staining of the intestine ofthe euryhaline marine goby Gillichthys mirabilis demonstratesthe presence of ANP-ergic neurons in the submucosa suggestingparacrine delivery to intestinal epithelial and smooth musclecells. ANP inhibits ion absorption across the goby intestine,supportingan osmoregulatory role for ANP.