Role of angiotensin II and oxidative stress on renal aquaporins expression in hypernatremic rats
J. physiol. biochem
; 70(2): 465-478, jun. 2014.
Article
em En
| IBECS
| ID: ibc-122967
Biblioteca responsável:
ES1.1
Localização: BNCS
ABSTRACT
The aim of this study was to assess whether endogenous Ang II and oxidative stress produced by acute hypertonic sodium overload may regulate the expression of aquaporin-1 (AQP-1) and aquaporin-2 (AQP-2) in the kidney. Groups of anesthetized male SpragueDawley rats were infused with isotonic saline solution (control) or with hypertonic saline solution (Na group, 1 M NaCl), either alone or with losartan (10 mg kg−1) or tempol (0.5 mg min−1 kg−1) during 2 h. Renal function parameters were measured. Groups of unanesthetized animals were injected intraperitoneally with hypertonic saline solution, with or without free access to water intake, Na+W, and Na−W, respectively. The expression of AQP-1, AQP-2, Ang II, eNOS, and NF-kB were evaluated in the kidney by Western blot and immunohistochemistry. AQP-2 distribution was assessed by immunofluorescence. Na group showed increased natriuresis and diuresis, and Ang II and NF-kB expression, but decreased eNOS expression. Losartan or tempol enhanced further the diuresis, and AQP-2 and eNOS expression, as well as decreased Ang II and NF-kB expression. Confocal immunofluorescence imaging revealed labeling of AQP-2 in the apical plasma membrane with less labeling in the intracellular vesicles than the apical membrane in kidney medullary collecting duct principal cells both in C and Na groups. Importantly, our data also show that losartan and tempol induces a predominantly accumulation of AQP-2 in intracellular vesicles. In unanesthetized rats, Na+W group presented increased diuresis, natriuresis, and AQP-2 expression (112 ± 25 vs 64 ± 16; *p < 0.05). Water deprivation increased plasma sodium and diuresis but decreased AQP-2 (46 ± 22 vs 112 ± 25; §p < 0.05) and eNOS expression in the kidney. This study is a novel demonstration that renal endogenous Ang II-oxidative stress, induced in vivo in hypernatremic rats by an acute sodium overload, regulates AQP-2 expression
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Coleções:
06-national
/
ES
Base de dados:
IBECS
Assunto principal:
Angiotensina II
/
Estresse Oxidativo
/
Aquaporinas
/
Hiponatremia
Limite:
Animals
Idioma:
En
Revista:
J. physiol. biochem
Ano de publicação:
2014
Tipo de documento:
Article