title: Evidence that brain angiotensin II is involved in both thirst and sodium appetite in baboons.
abstract: The roles of ANG II in the brain mechanisms subserving thirst and Na appetite in baboons were investigated by chronic intracerebroventricular infusions of ANG II and AT1-receptor antagonists using subcutaneous miniosmotic pumps and by oral administration of captopril. ANG II at 3 or 5 micrograms/h for 7 days increased water intake from 2,455 +/- 107 to 7,052 +/- 562 ml/day by day 6 and 300 mM NaCl intake from 8.3 +/- 1.1 to 275 +/- 87 mmol/day by day 5. Concurrent intracerebroventricular losartan (300 micrograms/h) did not substantially reduce these responses, but they were abolished by intracerebroventricular ZD-7155 (50 micrograms/h). The increase of 300 mM NaCl intake when it was offered after intramuscular injection of furosemide, 2 mg . kg-1 . day-1 for 3 days, was unaltered by intracerebroventricular losartan (300 micrograms/h) but was reduced by intracerebroventricular ZD-7155 (50 micrograms/h) infused throughout Na depletion/repletion; oral captopril (1 g, 3 and 18 h before access to 300 mM NaCl) also reduced NaCl intake. Restriction of water intake to 25% of daily intake for 3 days caused a high intake of water on day 4, and this was reduced by intracerebroventricular losartan (300 micrograms/h) infused throughout the period of water restriction/rehydration. These novel results in a primate species suggest that brain ANG II is involved in both thirst and Na appetite, acting via AT1 receptors.
authors.affiliation: Southwest Foundation for Biomedical Research, San Antonio, Texas 78245-0549, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Blair-West
authors.forename: K D
authors.initials: KD
authors.lastname: Carey
authors.forename: D A
authors.initials: DA
authors.lastname: Denton
authors.forename: R S
authors.initials: RS
authors.lastname: Weisinger
authors.forename: R E
authors.initials: RE
authors.lastname: Shade
mesh_terms: D000284:Administration, Oral; D000804:Angiotensin II / Q000502:physiology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001066:Appetite / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D002216:Captopril / Q000008:administration & dosage; D004326:Drinking / Q000502:physiology; D007276:Injections, Intraventricular; D019808:Losartan / Q000008:administration & dosage; D008297:Male; D009287:Naphthyridines / Q000008:administration & dosage; D010215:Papio; D011945:Receptors, Angiotensin / Q000502:physiology*; D012982:Sodium, Dietary / Q000008:administration & dosage
chemical_list: D057911:Angiotensin Receptor Antagonists; D009287:Naphthyridines; D011945:Receptors, Angiotensin; D012982:Sodium, Dietary; C095905:ZD 7155; D000804:Angiotensin II; D002216:Captopril; D019808:Losartan