Endogenous hydrogen peroxide in paraventricular nucleus mediating cardiac sympathetic afferent reflex and regulating sympathetic activity.
We previously reported that reactive oxygen species (ROS) in paraventricular nucleus (PVN) mediated cardiac sympathetic afferent reflex (CSAR). The present study investigated the role of endogenous hydrogen peroxide (H(2)O(2)), a ROS, in the PVN in mediating the CSAR and regulating sympathetic activity. The CSAR was evaluated by the response of renal sympathetic nerve activity (RSNA) to epicardial application of bradykinin (BK) in rats. Bilateral microinjection of polyethylene glycol-catalase (PEG-CAT, an analogue of endogenous catalase) or polyethylene glycol-superoxide dismutase (PEG-SOD, an analogue of endogenous superoxide dismutase) into the PVN abolished the CSAR, decreased baseline RSNA and mean arterial pressure (MAP). Moreover, pretreatment with PEG-CAT or PEG-SOD blocked the enhanced CSAR and RSNA responses induced by exogenous angiotensin II (Ang II) in the PVN. Aminotriazole (ATZ, a catalase inhibitor) alone potentiated the CSAR, increased RSNA and MAP, but failed to augment the Ang II-induced CSAR enhancement responses. Pretreated with PEG-SOD, ATZ still increased baseline RSNA and MAP but inhibited the CSAR and Ang II-induced CSAR and RSNA enhancement responses. These results suggested that endogenous H(2)O(2) in the PVN mediated both the CSAR and Ang II-induced CSAR enhancement responses. H(2)O(2) in the PVN were involved in regulating sympathetic activity and arterial pressure.
Yu
Yang
Y
Department of Physiology, Nanjing Medical University, Nanjing 210029, China.
Zhong
Ming-Kui
MK
Li
Jing
J
Sun
Xiu-Lan
XL
Xie
Gui-Qing
GQ
Wang
Wei
W
Zhu
Guo-Qing
GQ
D000640:Amitrole / Q000494:pharmacology; D000804:Angiotensin II / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002374:Catalase / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006321:Heart / Q000294:innervation*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007668:Kidney / Q000294:innervation; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*
D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; C070295:catalase-polyethylene glycol; D000804:Angiotensin II; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; C063471:polyethylene glycol-superoxide dismutase; D000640:Amitrole