ABSTRACT
Atrial natriuretic peptides (ANP) are a family of different peptides originally identified in the heart. Three distinct peptides may be distinguished at present: ANP, brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). Since the discovery of ANP, it has become apparent that this family of peptides has actions which suggest that they may act as physiological antagonists of angiotensin II (AngII). Initial observations showed that ANP relaxed blood vessels contracted by AngII. The nature of the interaction between ANP and AngII in the adrenal cortex has been the subject of a number of studies yielding controversial data and remains unexplained. There is little doubt that ANP increases cyclic guanosine monophosphate in the adrenal and that AngII stimulates phospholipase C, calcium release, and calcium entry into the adrenal cell. An antagonistic relationship between brain AngII and ANP is also evident in the modulation of sodium appetite. In sodium-depleted rats sodium appetite can be significantly blunted by icv ANP.
