Premium
Oxidative stress mediates the pressor response to acute environmental stress in Dahl salt‐sensitive rats
Author(s) -
D’Angelo Gerard,
Pollock David M,
Pollock Jennifer S
Publication year - 2006
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.20.4.a357-c
Subject(s) - oxidative stress , medicine , endocrinology , heart rate , epinephrine , blood pressure , superoxide dismutase , isoprostane , mean arterial pressure , chemistry , lipid peroxidation
Elevated superoxide has been shown to cause an increase in vasoconstrictor sensitivity, and to contribute to the development of hypertension in Dahl salt‐sensitive (DS) rats. Therefore we tested the hypothesis that tempol, a superoxide dismutase mimetic, inhibits the pressor response to acute environmental stress in DS rats. Stress was induced by restraint and administration of air jet pulses (3 minutes) in rats maintained on a normal salt diet before and after 3‐day treatment with tempol (1mM) in the drinking water. Mean arterial pressure (MAP) and heart rate (HR) were monitored by telemetry. Tempol had no effect on 24‐hour MAP, but caused a small, but significant decrease in baseline HR (411±3 vs. 397±3 beats/min, p<0.05). Baseline plasma 8‐isoprostane, endothelin‐1 (ET‐1), and epinephrine (Epi) concentrations were not changed by tempol treatment. Acute stress produced an increase in blood pressure; however, the integrated response (area under the curve) was significantly reduced in tempol‐treated rats (22.3±3.2 vs. 13.6±3.1 mmHg x 3 min, p<0.05). Moreover, tempol abolished the stress‐induced rise in 8‐isoprostane (1.85±0.32 vs. 1.01±0.07 fold change, p<0.05), and significantly reduced the stress‐mediated increases in Epi (548±49 vs. 385±46 pg/ml, p<0.05) and HR (515±8 vs. 487±9 beats/min, p<0.05); tempol had no effect on the stress‐induced rise in ET‐1. These data demonstrate that oxidative stress contributes to the pressor response to acute stress in DS rats independent of ET‐1. We conclude that tempol suppresses the pressor response by reducing sympathetic activation of the heart. [Supported by AHA‐0530361N, HL‐69999]