Central angiotensin II induces sodium bicarbonate intake in the rat.
The aim of this work was to test mineral preference in hydrated rats that received a pulse intracerebroventricular (icv(p)) injection of ANG II at a dipsogenic dose (50 ng). The icv(p) ANG II induced a four-fold higher ingestion of 0.15M NaHCO(3) than of other mineral solutions at palatable concentrations (0.15M NaCl, 0.05 mM CaCl(2) and 0.01 M KCl) in a five-bottle test with water available in a fifth bottle; water intake was not consistently high in this test. Contrary to what is predicted by the mineralocorticoid/angiotensin II synergy hypothesis, the 0.15M NaCl intake in the five-bottle test was not enhanced by icv(p) ANG II preceded by deoxycorticosterone (DOCA) treatment (2.5mg/day for 3 days); neither was the NaHCO(3) intake. This result contrasted with the vigorous ingestion of both isotonic sodium solutions, but mostly of NaCl, rather than of other fluids, by sodium-depleted (furosemide 10mg sc+24h removal ambient sodium) rats in a sodium appetite test. The results suggest that mineralocorticoid combined to icv(p) ANG II does not simulate the sodium preference shown during sodium appetite. The results also show that a dipsogenic dose of central ANG II induces a reliable ingestion of isotonic sodium bicarbonate in the rat.
David
Richard B
RB
Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
Menani
José V
JV
De Luca
Laurival A
LA
D000804:Angiotensin II / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D011897:Random Allocation; D051381:Rats; D017693:Sodium Bicarbonate / Q000008:administration & dosage*; D014882:Water-Electrolyte Balance / Q000187:drug effects* / Q000502:physiology*
D000804:Angiotensin II; D017693:Sodium Bicarbonate