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Sympathetic Modulation Decreases in Rats with Renovascular Hypertension Treated with Chronic Administration of Catalase Inhibitor
Author(s) -
Lauar Mariana Ruiz,
De Luca Laurival Antonio,
De Paula Patricia Maria,
Colombari Débora S A,
Colombari Eduardo,
Andrade Carina A F,
Menani José Vanderlei
Publication year - 2016
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.30.1_supplement.731.2
Subject(s) - saline , blood pressure , renovascular hypertension , mean arterial pressure , endocrinology , medicine , renin–angiotensin system , chemistry , heart rate
Previous studies have shown that the increase of endogenous hydrogen peroxide (H 2 O 2 ) with the administration of the catalase inhibitor 3‐amino‐1,2,4‐triazol (ATZ) intravenously acutely reduced mean arterial pressure (MAP) and the pressor response induced by angiotensin II intracerebroventricularly in renal hypertensive rats. Recent data have also shown that chronic subcutaneous (sc) administration of ATZ reduced MAP in 2‐kidneys, 1‐clip (2K1C) hypertensive rats. In the present study, we analyzed the autonomic modulation of cardiovascular function in 2K1C hypertensive rats treated with chronic sc injection of ATZ. Male Holtzman rats (initial weight 150–180 g, n=7–11/group) received a silver clip around the left renal artery to generate 2K1C hypertension. After 6 weeks of the surgery, rats were treated with ATZ or saline for 7 days before the recording of arterial pressure and the analysis of systolic blood pressure (SBP) and pulse interval (PI) variability using power spectral analysis. Baseline MAP was increased in 2K1C rats compared to sham (207 ± 9, vs. 100 ± 2 mmHg, respectively). ATZ (600 mg/kg/day) in 2K1C rats reduced MAP (162 ± 10 vs. saline 209 ± 5 mmHg), the low frequency (LF) of SBP (3.3 ± 0.5, vs. saline 7.6±1.5 mmHg 2 ) and LF of PI (14.6±3, vs. saline: 31±3 normalized units). ATZ also increased high frequency (HF) of PI (85±3, vs. saline: 68±3 normalized units) and improved the sympathovagal balance calculated for LF/HF ratio of PI variability (0.2±0.05, vs. saline: 0.52±0.09). The results suggest that the treatment with ATZ reduces MAP in 2K1C hypertensive rats by reducing the modulation of sympathetic activity. Support or Funding Information FAPESP, CNPq and PROPE/FUNDUNESP.