Reactive oxygen species in the paraventricular nucleus mediate the cardiac sympathetic afferent reflex in chronic heart failure rats.
The aim of this study was to determine whether reactive oxygen species (ROS) in the paraventricular nucleus (PVN) mediate both the cardiac sympathetic afferent reflex (CSAR) and angiotensin II-induced CSAR enhancement in chronic heart failure (CHF) rats. CSAR was evaluated from the responses of renal sympathetic nerve activity (RSNA) to epicardial application of bradykinin. In both CHF and sham-operated rats, PVN microinjection of the superoxide anion scavengers tempol or tiron almost abolished the CSAR, but the superoxide dismutase inhibitor DETC potentiated the CSAR. PVN pretreatment with tempol or tiron abolished, whereas DETC augmented, the angiotensin II-induced CSAR enhancement. In CHF rats, superoxide anion and malondialdehyde (MDA) levels in the PVN were increased, but were normalized by the AT(1) receptor antagonist losartan. PVN microinjection of tempol decreased superoxide anion and MDA levels, but epicardial application of bradykinin or PVN microinjection of angiotensin II increased superoxide anion and MDA to higher levels in CHF rats than in sham-operated rats. These results indicate that ROS in the PVN mediates the CSAR and the effect of angiotensin II in the PVN on the CSAR in both CHF and sham-operated rats. Increased ROS in the PVN are involved in the enhanced CSAR in CHF.
Han
Ying
Y
Department of Physiology, Nanjing Medical University, Nanjing 210029, China.
Shi
Zhen
Z
Zhang
Feng
F
Yu
Yang
Y
Zhong
Ming-Kui
MK
Gao
Xing-Ya
XY
Wang
Wei
W
Zhu
Guo-Qing
GQ
D000344:Afferent Pathways / Q000187:drug effects*; D000804:Angiotensin II / Q000502:physiology*; D047228:Angiotensin II Type 1 Receptor Blockers; D000818:Animals; D006321:Heart / Q000294:innervation*; D006333:Heart Failure / Q000503:physiopathology*; D019808:Losartan / Q000494:pharmacology; D008297:Male; D023421:Models, Animal; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species; D044140:Receptor, Angiotensin, Type 1 / Q000187:drug effects; D011945:Receptors, Angiotensin; D013481:Superoxides; D013564:Sympathetic Nervous System; D014662:Vasoconstrictor Agents
D047228:Angiotensin II Type 1 Receptor Blockers; D017382:Reactive Oxygen Species; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin; D014662:Vasoconstrictor Agents; D013481:Superoxides; D000804:Angiotensin II; D019808:Losartan