Atrial natriuretic peptide (ANP) as a neuropeptide: interaction with angiotensin II on volume control and renal sodium handling.

1. Angiotensin II (ANG II) and atrial natriuretic peptide (ANP) are functionally antagonistic circulating hormones involved in blood pressure and body fluid regulation. An inappropriate atrial secretion of ANP has been implicated in the pathogenesis of hypertension, but clinical and experimental results on the role of ANP in hypertension are still conflicting. 2. In the brain both peptides have been localized in close proximity, preferentially in areas involved in central cardiovascular, electrolyte and volume control. ANP was shown to inhibit ANG II-induced drinking, release of pituitary hormones and natriuresis, and to induce sodium retention when given alone. 3. These findings suggest that also in the brain ANG II and ANP exert functionally antagonistic effects. However, in contrast to their peripheral effects, ANG II induces natriuresis while ANP appears to cause antinatriuresis in the brain.