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Oxidative stress in the sympathetic premotor neurons contributes to sympathetic activation in renovascular
Author(s) -
OliveiraSales Elizabeth Barbosa,
Nishi Erika Emy,
Carillo Bruno Arruda,
Boim Mirian Aparecida,
Dolnikoff Miriam Sterman,
Bergamaschi Cássia Toledo,
Campos Ruy R
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb52
Subject(s) - rostral ventrolateral medulla , medicine , endocrinology , hypothalamus , oxidative stress , nadph oxidase , receptor , superoxide , chemistry , renovascular hypertension , sympathetic nervous system , medulla oblongata , blood pressure , central nervous system , enzyme , biochemistry
Based on previous data, we hypothesized that an increase of Ang II ‐ via the AT‐1 receptor ‐ in the rostral ventrolateral medulla (RVLM) and the paraventricular nucleus of the hypothalamus (PVN) could activate NAD(P)H oxidase that will produce superoxides resulting in increased sympathetic activity and hypertension. The mRNA expression of AT‐1 receptors, NAD(P)H oxidase subunits (p47phox and gp91phox) and CuZnSOD were analyzed in the RVLM and PVN of male Wistar rats (Goldblatt hypertension model ‐ 2K‐1C). Additionally, we administered Tempol‐1 and 5 nmol into the RVLM, PVN or systemically. The mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) were analyzed. The AT‐1 mRNA expression and NAD(P)H oxidase subunits was greater in the RVLM and PVN in 2K‐1C compared to the control group. Furthermore, the CuZnSOD expression was similar in both groups. Tempol‐1nmol into the RVLM reduced MAP (15 ± 1%) and RSNA (11± 2%) only in 2K‐1C rats. Tempol (5 nmol) in the same region decreased the MAP (12± 4%) and RSNA (20 ±7%) respectively, only in 2K‐1C. In the PVN, Tempol‐5nmol resulted in a significant fall in the MAP (24 ± 1%) and in the RSNA (7.9 ± 2%) only in the 2K‐1C. Acute IV infusion of Tempol decreased MAP and RSNA in the 2K‐1C but not in the control rats. The data suggest that the hypertension and sympathoexcitation in 2K‐1C rats were associated with an increase in oxidative stress within the RVLM, the PVN and systemically. Supported by FAPESP.