Atrial natriuretic peptide in brain preoptic areas: implications for fluid and salt homeostasis

The influence of adrenalectomy and mineralocorticoid and glucocorticoid treatment on atrial natriuretic peptide (ANP) concentration of 18 microdissected rat brain nuclei was investigated. Adrenalectomy increased ANP levels highly in those brain areas that control water intake (the subfornical organ and supraoptic nucleus) and in the drinking center (the perifornical nucleus and the lateral hypothalamus). In all of these brain regions, aldosterone elevated ANP levels in intact animals. Adrenalectomy decreased ANP levels markedly in the OVLT and preoptic periventricular nucleus, which constitute the so-called AV3V region. The ANP level of these two brain areas was nearly restored to baseline levels both after administration of sodium chloride and after replacement of aldosterone, whereas dexamethasone treatment failed to have any effect.