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High Salt Dietary Increases Reactive Oxygen Species Generation in the Brain and Contributes to the Development of Central Activation of the Sympathetic Nervous System in Spontaneously Hypertensive Rats
Author(s) -
Koga Yasuaki,
Hirooka Yoshioka,
Nozoe Masatsugu,
Sagara Yoji,
Sunagawa Kenji
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.a358-c
Subject(s) - rostral ventrolateral medulla , medicine , endocrinology , sympathetic nervous system , tbars , reactive oxygen species , central nervous system , blood pressure , norepinephrine , hypothalamus , chemistry , medulla oblongata , oxidative stress , lipid peroxidation , biochemistry , dopamine
High dietary sodium causes sympathetic hyperactivity and increases resting blood pressure (BP) in spontaneously hypertensive rats (SHR). However, the mechanisms involved in such changes in activation of the sympathetic nervous system are not fully understood. The aim of the present study is thus to examine whether reactive oxygen species (ROS) of SHR on a high salt dietary increases in the rostral ventrolateral medulla (RVLM) where the vasomotor center is located. Male SHR (6‐week‐old) were fed with high salt diet (8% NaCl) or low salt diet (0.5% NaCl) for 6 weeks. BP was significantly higher in high salt diet than low salt group from 9‐week‐ old. We evaluated ROS in the brain (cortex, cerebellum, hypothalamus, and RVLM) by thiobarbituric acid‐reactive substances (TBARS) at 12‐week‐old. Urinary norepinephrine excretion in high salt diet group was significantly higher than that of low salt diet group at 12‐week‐old. To confirm the role of ROS in the RVLM in blood pressure regulation, tempol was microinjected bilaterally into the RVLM in high and low salt groups at 12‐week‐old. A greater depressor response was observed in the high salt group than in the low salt group. These results suggest that the salt‐induced increases in ROS in the RVLM of SHR is involved in further activation of sympathetic nervous system in this genetically hypertensive model.