Preoptic neuronal circuit: atrial natriuretic peptide-containing neurons are sensitive to acute and chronic alterations in body fluid volume.
Atrial antriuretic peptide (ANP) concentrations were determined in rostral preoptic midline structures (organum vasculosum laminae terminalis, periventricular and medial preoptic nuclei) and in the subfornical organ by radioimmunoassay in rats with acute volume load and volume depletion, as well as during water deprivation. ANP-containing neuronal elements in all four areas (to a lesser extent in the medial preoptic nucleus) reacted very sensitively to acute and chronic changes in body fluid volume: volume load resulted in an elevation, volume depletion in a depletion in ANP concentrations. These alterations were significant and completely matched changes in plasma ANP concentrations. Water deprivation increased ANP levels on the first experimental day, followed by a marked depletion in the organum vasculosum laminae terminalis, subfornical organ and the periventricular preoptic nucleus. It is hypothesized that three major neuropeptides (angiotensin II, vasopressin, ANP) regulate body fluid volume through a close neuronal network along a subfornical organ-preoptic-hypothalamic axis. The subfornical organ, which is very rich in angiotensin II and ANP receptors, serves as an open gate for circulating hormones and is neuronally interconnected with volume-sensitive ANP neurons in the preoptic area (organum vasculosum laminae terminalis and preoptic periventricular nucleus). Neurons in the subfornical organ and the preoptic area project to the supraoptic and paraventricular nuclei and control the activity of vasopressin-synthesizing neurosecretory cells.
Palkovits
M
M
Laboratory of Neuromorphology, Semmelweis University Medical School, Budapest, Hungary.
Bahner
U
U
Geiger
H
H
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001826:Body Fluids / Q000502:physiology*; D001921:Brain / Q000378:metabolism; D007275:Injections, Intravenous; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D011301:Preoptic Area / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000494:pharmacology; D013356:Subfornical Organ / Q000378:metabolism; D014868:Water Deprivation / Q000502:physiology
D012965:Sodium Chloride; D009320:Atrial Natriuretic Factor