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Endogenous hydrogen peroxide in paraventricular nucleus mediates sympathetic activation and enhanced cardiac sympathetic afferent reflex in renovascular hypertensive rats.
Exp Physiol. 2011 Dec; 96(12):1282-92.EP

Abstract

An enhancement of the cardiac sympathetic afferent reflex (CSAR) contributes to sympathetic activation in renovascular hypertension. Angiotensin II in the paraventricular nucleus (PVN) augments the CSAR and increases sympathetic outflow and blood pressure. The present study aimed to determine whether endogenous hydrogen peroxide in the PVN mediated the enhanced CSAR, sympathetic activity and the effects of angiotensin II in the PVN in renovascular hypertension induced by the two-kidney, one-clip method (2K1C) in rats. At the end of the fourth week, the rats underwent sino-aortic and vagal denervation under general anaesthesia with urethane and α-chloralose. Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded. The CSAR was evaluated by the RSNA response to epicardial application of bradykinin. Microinjection of polyethylene glycol-catalase (PEG-CAT), an analogue of endogenous catalase, into the PVN decreased the RSNA and MAP and abolished the CSAR in both sham-operated and 2K1C rats. Microinjection into the PVN of the catalase inhibitor, aminotriazole, increased the RSNA and MAP and enhanced the CSAR. The effects of PEG-CAT or aminotriazole were greater in 2K1C rats than in sham-operated animals. The effects of angiotensin II in the PVN were abolished by pretreatment with PEG-CAT in both sham-operated and 2K1C rats; however, aminotriazole failed to potentiate the effects of angiotensin II. The catalase activity was decreased but the H(2)O(2) levels were increased in the PVN of 2K1C rats. These results indicate that endogenous H(2)O(2) in the PVN not only mediates the enhanced sympathetic activity and CSAR, but also the effects of angiotensin II in the PVN in renovascular hypertensive rats.

Authors+Show Affiliations

Department of Physiology, Nanjing Medical University, Nanjing 210029, China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21890522

Citation

Xu, Yao, et al. "Endogenous Hydrogen Peroxide in Paraventricular Nucleus Mediates Sympathetic Activation and Enhanced Cardiac Sympathetic Afferent Reflex in Renovascular Hypertensive Rats." Experimental Physiology, vol. 96, no. 12, 2011, pp. 1282-92.
Xu Y, Gao Q, Gan XB, et al. Endogenous hydrogen peroxide in paraventricular nucleus mediates sympathetic activation and enhanced cardiac sympathetic afferent reflex in renovascular hypertensive rats. Exp Physiol. 2011;96(12):1282-92.
Xu, Y., Gao, Q., Gan, X. B., Chen, L., Zhang, L., Zhu, G. Q., & Gao, X. Y. (2011). Endogenous hydrogen peroxide in paraventricular nucleus mediates sympathetic activation and enhanced cardiac sympathetic afferent reflex in renovascular hypertensive rats. Experimental Physiology, 96(12), 1282-92. https://doi.org/10.1113/expphysiol.2011.059733
Xu Y, et al. Endogenous Hydrogen Peroxide in Paraventricular Nucleus Mediates Sympathetic Activation and Enhanced Cardiac Sympathetic Afferent Reflex in Renovascular Hypertensive Rats. Exp Physiol. 2011;96(12):1282-92. PubMed PMID: 21890522.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Endogenous hydrogen peroxide in paraventricular nucleus mediates sympathetic activation and enhanced cardiac sympathetic afferent reflex in renovascular hypertensive rats. AU - Xu,Yao, AU - Gao,Qing, AU - Gan,Xian-Bing, AU - Chen,Lei, AU - Zhang,Lei, AU - Zhu,Guo-Qing, AU - Gao,Xing-Ya, Y1 - 2011/09/02/ PY - 2011/9/6/entrez PY - 2011/9/6/pubmed PY - 2012/3/23/medline SP - 1282 EP - 92 JF - Experimental physiology JO - Exp. Physiol. VL - 96 IS - 12 N2 - An enhancement of the cardiac sympathetic afferent reflex (CSAR) contributes to sympathetic activation in renovascular hypertension. Angiotensin II in the paraventricular nucleus (PVN) augments the CSAR and increases sympathetic outflow and blood pressure. The present study aimed to determine whether endogenous hydrogen peroxide in the PVN mediated the enhanced CSAR, sympathetic activity and the effects of angiotensin II in the PVN in renovascular hypertension induced by the two-kidney, one-clip method (2K1C) in rats. At the end of the fourth week, the rats underwent sino-aortic and vagal denervation under general anaesthesia with urethane and α-chloralose. Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded. The CSAR was evaluated by the RSNA response to epicardial application of bradykinin. Microinjection of polyethylene glycol-catalase (PEG-CAT), an analogue of endogenous catalase, into the PVN decreased the RSNA and MAP and abolished the CSAR in both sham-operated and 2K1C rats. Microinjection into the PVN of the catalase inhibitor, aminotriazole, increased the RSNA and MAP and enhanced the CSAR. The effects of PEG-CAT or aminotriazole were greater in 2K1C rats than in sham-operated animals. The effects of angiotensin II in the PVN were abolished by pretreatment with PEG-CAT in both sham-operated and 2K1C rats; however, aminotriazole failed to potentiate the effects of angiotensin II. The catalase activity was decreased but the H(2)O(2) levels were increased in the PVN of 2K1C rats. These results indicate that endogenous H(2)O(2) in the PVN not only mediates the enhanced sympathetic activity and CSAR, but also the effects of angiotensin II in the PVN in renovascular hypertensive rats. SN - 1469-445X UR - https://www.unboundmedicine.com/medline/citation/21890522/Endogenous_hydrogen_peroxide_in_paraventricular_nucleus_mediates_sympathetic_activation_and_enhanced_cardiac_sympathetic_afferent_reflex_in_renovascular_hypertensive_rats_ L2 - https://doi.org/10.1113/expphysiol.2011.059733 DB - PRIME DP - Unbound Medicine ER -