title: Mechanisms of altered sodium excretion after preoptic hypothalamic lesions.
abstract: These experiments investigated cardiovascular and hormonal responses during the natriuresis and subsequent sodium retention following electrolytic lesions of the periventricular tissue surrounding the anteroventral third ventricle (AV3V-X) in the rat. Four hours following treatment, AV3V-X resulted in a significant increase in blood pressure (18 +/- 3 mmHg), bradycardia (-68 +/- 20 beats/min), and natriuresis (212 +/- 36 mu eq/h), compared with control-operated (control: 2 +/- 4 mmHg, -14 +/- 18 beats/min, 89 +/- 34 mu eq/h) and unanesthetized control (UC) animals (-1 +/- 3 mmHg, -5 +/- 12 beats/min, 74 +/- 25 mu eq/h). Preventing the hypertensive response in AV3V-X rats abolished the natriuresis. Twenty-four hours after treatment, blood pressure, heart rate, urine flow, and sodium excretion were similar between experimental groups. However, sodium excretion by AV3V-X rats was significantly smaller than control 24-48 h following treatment. AV3V-X rats had significantly elevated plasma concentrations of aldosterone and corticosterone 4, 24, and 48 h and increased plasma renin 24 and 48 h after treatment. These data suggest that the acute natriuresis following AV3V-X is mediated by increased arterial blood pressure, whereas the subsequent sodium retention could be due to activation of the renin-aldosterone system.
authors.affiliation: Department of Physiology and Biophysics, University of Tennesse, Memphis 38163.
authors.forename: S L
authors.initials: SL
authors.lastname: Bealer
authors.forename: R W
authors.initials: RW
authors.lastname: Caldwell
authors.forename: E
authors.initials: E
authors.lastname: Songu-Mize
mesh_terms: D000450:Aldosterone / Q000097:blood; D000818:Animals; D003345:Corticosterone / Q000097:blood; D004326:Drinking; D007031:Hypothalamus / Q000502:physiology*; D008297:Male; D009318:Natriuresis; D011301:Preoptic Area / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood
chemical_list: D000450:Aldosterone; D012083:Renin; D003345:Corticosterone