Please use this identifier to cite or link to this item: http://repositorio.ufes.br/handle/10/586
Title: A low concentration of ouabain (0.18 µg/kg) enhances hypertension in spontaneously hypertensive rats by inhibiting the Na+ pump and activating the renin-angiotensin system
Authors: Siman, Fabiana Dayse Magalhaes
Stefanon, Ivanita
Vassallo, Dalton Valentim
Padilha, Alessandra Simão
Keywords: Ouabaína;Hipertensão;Sistema Renina-Angiotensina;Ouabain;Hypertension;Renin-angiotensin system
Issue Date: Aug-2010
Citation: SIMAN, F.D.M. et al. A low concentration of ouabain (0.18 µg/kg) enhances hypertension in spontaneously hypertensive rats by inhibiting the Na+ pump and activating the renin-angiotensin system. Braz J Med Biol Res, Ribeirão Preto, v. 43, n. 8, p. 767-776, ago. 2010. Disponível em: <http://www.scielo.br/pdf/bjmbr/v43n8/227.pdf>. Acesso em: 7 fev. 2011.
Abstract: We investigated the effects of low ouabain concentrations on systolic (SAP) and diastolic (DAP) arterial pressures and on pressor reactivity in 3-month-old male spontaneously hypertensive rats (SHR). Arterial blood pressure (BP) and pressor reactivity to phenylephrine (PHE) were investigated before and after 0.18 μg/kg ouabain administration (N = 6). The influence of hexamethonium (N = 6), canrenone (N = 6), enalapril (N = 6), and losartan (N = 6) on ouabain actions was evaluated. Ouabain increased BP (SAP: 137 ± 5.1 to 150 ± 4.7; DAP: 93.7 ± 7.7 to 116 ± 3.5 mmHg; P < 0.05) but did not change PHE pressor reactivity. Hexamethonium reduced basal BP in control but not in ouabain-treated rats. However, hexamethonium + ouabain increased DAP sensitivity to PHE. Canrenone did not affect basal BP but blocked ouabain effects on SAP. However, after canrenone + ouabain administration, DAP pressor reactivity to PHE still increased. Enalapril and losartan reduced BP and abolished SAP and DAP responses to ouabain. Enalapril + ouabain reduced DAP reactivity to PHE, while losartan + ouabain reduced SAP and DAP reactivity to PHE. In conclusion, a small dose of ouabain administered to SHR increased BP without altering PHE pressor reactivity. Although the renin-angiotensin system (RAS), Na+ pump and autonomic reflexes are involved in the effects of ouabain on PHE reactivity, central mechanisms might blunt the actions of ouabain on PHE pressor reactivity. The effect of ouabain on SAP seems to depend on the inhibition of both Na+ pump and RAS, whereas the effect on DAP seems to depend only on RAS.
URI: http://repositorio.ufes.br/handle/10/586
ISSN: 0100-879X
Appears in Collections:DCFSI - Artigos publicados em periódicos

Files in This Item:
File Description SizeFormat 
227.pdf609.08 kBAdobe PDFView/Open


This item is licensed under a Creative Commons License Creative Commons