Signal Transduction of Mineralocorticoid and Angiotensin II Receptors in the Central Control of Sodium Appetite: A Narrative Review

Abstract

Sodium appetite is an innate behavior occurring in response to sodium depletion that induces homeostatic responses such as the secretion of the mineralocorticoid hormone aldosterone from the zona glomerulosa of the adrenal cortex and the stimulation of the peptide hormone angiotensin II (ANG II). The synergistic action of these hormones signals to the brain the sodium appetite that represents the increased palatability for salt intake. This narrative review summarizes the main data dealing with the role of mineralocorticoid and ANG II receptors in the central control of sodium appetite. Appropriate keywords and MeSH terms were identified and searched in PubMed. References to original articles and reviews were examined, selected, and discussed. Several brain areas control sodium appetite, including the nucleus of the solitary tract, which contains aldosterone-sensitive HSD2 neurons, and the organum vasculosum lamina terminalis (OVLT) that contains ANG II-sensitive neurons. Furthermore, sodium appetite is under the control of signaling proteins such as mitogen-activated protein kinase (MAPK) and inositol 1,4,5-thriphosphate (IP3). ANG II stimulates salt intake via MAPK, while combined ANG II and aldosterone action induce sodium intake via the IP3 signaling pathway. Finally, aldosterone and ANG II stimulate OVLT neurons and suppress oxytocin secretion inhibiting the neuronal activity of the paraventricular nucleus, thus disinhibiting the OVLT activity to aldosterone and ANG II stimulation.

From Living in Saltwater to a Scarcity of Salt and Water, and Then an Overabundance of Salt—The Biological Roller Coaster to Which the Renin–Angiotensin System Has Had to Adapt: An Editorial

“…It is also a neural transmitter. In the brain stem, diencephalon and limbic system neural circuits controlling salt and water balance even behavior elements containing Ang II-releasing neurons [5,6]. These complex actions are very far from the original epithelial salt-conserving function of this archaic agonist.…”

“…Several mammals have a salt appetite, and humans are among them. A salt appetite might have had an additional advantage in early humans turning hunters: even unsalted meat has a fairly salty taste [5,6].…”