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Reduced reactive oxygen species generation in rostral ventrolateral medulla suppresses the pressor response induced by the excitation of the paraventricular nucleus of the hypothalamus in spontaneously hypertensive rats
Author(s) -
Nishihara Masaaki,
Hirooka Yoshitaka,
Matsukawa Ryuuichi,
Ito Koji,
Kishi Takuya,
Sunagawa Kenji
Publication year - 2010
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.24.1_supplement.1019.8
Subject(s) - rostral ventrolateral medulla , medicine , microinjection , endocrinology , excitatory postsynaptic potential , chemistry , hypothalamus , nucleus , medulla oblongata , angiotensin ii , receptor , central nervous system , neuroscience , biology
Background Increased generation of reactive oxygen species (ROS) in the rostral ventrolateral medulla (RVLM) contribute to the neural mechanism of hypertension. The RVLM receives excitatory synaptic inputs from the paraventricular nucleus (PVN). It is also suggested that the angiotensin II type 1 receptors in the RVLM are activated by the PVN stimulation. Therefore, we examined whether the excitatory synaptic inputs derived from the PVN mediate the ROS in the RVLM or not. Methods and Results We used 14 to 18‐week‐old male Wistar‐Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). We transfected adenovirus vectors encoding manganese superoxide dismutase gene (AdMnSOD) into the bilateral RVLM. Then, we microinjected bicuculline (BIC) (100pmol) into the unilateral PVN on day 7 after gene transfer. Microinjection of BIC into the PVN increased mean arterial blood pressure (MAP) in both SHR and MnSOD‐transfected SHR, however, the pressor response was significantly attenuated in MnSOD‐transfected SHR (SHR: 33±2 mmHg; MnSOD‐transfected SHR: 20±1 mmHg, n=5, P<0.05). Overexpression of MnSOD in the RVLM did not suppress BIC‐elicited MAP elevation in WKY rats (WKY rats: 14±1 mmHg; MnSOD‐transfected WKY rats: 13±1 mmHg, n=3). Conclusion Excitatory synaptic inputs arising from activation of the PVN to the RVLM are mediated, at least in part, by ROS generation in SHR, but not in WKY.