scholarly journals Intermedin in the Paraventricular Nucleus Attenuates Cardiac Sympathetic Afferent Reflex in Chronic Heart Failure Rats

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e94234 ◽  
Author(s):  
Xian-Bing Gan ◽  
Hai-Jian Sun ◽  
Dan Chen ◽  
Ling-Li Zhang ◽  
Hong Zhou ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Paraventricular Nucleus ◽  
Cardiac Sympathetic Afferent Reflex

AT1 receptor mRNA antisense normalizes enhanced cardiac sympathetic afferent reflex in rats with chronic heart failure

2004 ◽  
Vol 287 (4) ◽  
pp. H1828-H1835 ◽  
Author(s):  
Guo-Qing Zhu ◽  
Lie Gao ◽  
Yifan Li ◽  
Kaushik P. Patel ◽  
Irving H. Zucker ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Paraventricular Nucleus ◽  
Genetic Manipulation ◽  
Intracerebroventricular Administration ◽  
Renal Sympathetic Nerve Activity ◽  
Protein Levels ◽  
Coronary Ligation ◽  
Cardiac Sympathetic Afferent Reflex

Previous studies showed that the cardiac sympathetic afferent reflex (CSAR) is enhanced in dogs and rats with chronic heart failure (CHF) and that central ANG II type 1 receptors (AT1R) are involved in this augmented reflex. The aim of this study was to determine whether intracerebroventricular administration and microinjection of antisense oligodeoxynucleotides targeted to AT1R mRNA would attenuate the enhanced CSAR and decrease resting renal sympathetic nerve activity (RSNA) in rats with coronary ligation-induced CHF. The CSAR was elicited by application of bradykinin to the epicardial surface of the left ventricle. Reflex responses to epicardial administration of bradykinin were enhanced in rats with CHF. The response to bradykinin was determined every 50 min after intracerebroventricular administration (lateral ventricle) or microinjection (into paraventricular nucleus) of antisense or scrambled oligonucleotides to AT1R mRNA. AT1R mRNA and protein levels in the paraventricular nucleus were significantly reduced 5 h after administration of antisense. Antisense significantly decreased resting RSNA and normalized the enhanced CSAR responses to bradykinin in rats with CHF. Scrambled oligonucleotides did not alter resting RSNA or the enhanced responses to bradykinin in rats with CHF. No significant effects were found in sham-operated rats after administration of either antisense or scrambled oligonucleotides. These results strongly suggest that central AT1R mRNA antisense reduces expression of AT1R protein and normalizes the augmentation of this excitatory sympathetic reflex and that genetic manipulation of protein expression can be used to normalize the sympathetic enhancement in CHF.

scholarly journals Angiotensin-(1-7) in Paraventricular Nucleus Contributes to the Enhanced Cardiac Sympathetic Afferent Reflex and Sympathetic Activity in Chronic Heart Failure Rats

2017 ◽  
Vol 42 (6) ◽  
pp. 2523-2539 ◽  
Author(s):  
Xingsheng Ren ◽  
Feng Zhang ◽  
Mingxia Zhao ◽  
Zhenzhen Zhao ◽  
Shuo Sun ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Signaling Pathway ◽  
Paraventricular Nucleus ◽  
Superoxide Anion ◽  
Coronary Artery Ligation ◽  
Ang Ii ◽  
Sympathetic Activation ◽  
Mas Receptor ◽  
Cardiac Sympathetic Afferent Reflex

Background/Aims: Cardiac sympathetic afferent reflex (CSAR) enhancement contributes to exaggerated sympathetic activation in chronic heart failure (CHF). The current study aimed to investigate the roles of angiotensin (Ang)-(1-7) in CSAR modulation and sympathetic activation and Ang-(1-7) signaling pathway in paraventricular nucleus of CHF rats. Methods: CHF was induced by coronary artery ligation. Responses of renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) to epicardial application of capsaicin were used to evaluate CSAR in rats with anesthesia. Results: Ang-(1-7) increased RSNA, MAP, CSAR activity, cAMP level, NAD(P)H oxidase activity and superoxide anion level more significantly in CHF than in sham-operated rats, while Mas receptor antagonist A-779 had the opposite effects. Moreover, Ang-(1-7) augmented effects of Ang II in CHF rats. The effects of Ang-(1-7) were blocked by A-779, adenylyl cyclase inhibitor SQ22536, protein kinase A inhibitor Rp-cAMP, superoxide anion scavenger tempol and NAD(P)H oxidase inhibitor apocynin. Mas and AT1 receptor protein expressions, Ang-(1-7) and Ang II levels in CHF increased. Conclusions: These results indicate that Ang-(1-7) in paraventricular nucleus enhances CSAR and sympathetic output not only by exerting its own effects but also by augmenting the effects of Ang II through Mas receptor in CHF. Endogenous Ang-(1-7)/Mas receptor activity contributes to CSAR enhancement and sympathetic activation in CHF, and NAD(P)H oxidase-derived superoxide anions and the cAMP-PKA signaling pathway are involved in mediating the effects of Ang-(1-7) in CHF.

Abstract 15532: Altered Ubiquitination and Stability of Protein Inhibitor of Neuronal Nitric Oxide Synthase in the Paraventricular Nucleus of Chronic Heart Failure Rats: Role of Angiotensin II

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Neeru Sharma ◽  
Xuefei Liu ◽  
Hong Zheng ◽  
Kaushik Patel
Keyword(s):  
Nitric Oxide ◽  
Heart Failure ◽  
Angiotensin Ii ◽  
Chronic Heart Failure ◽  
Paraventricular Nucleus ◽  
Neuronal Nitric Oxide Synthase ◽  
Ang Ii ◽  
Protein Inhibitor ◽  
Ubiquitin Proteasome ◽  
Oxide Synthase

Introduction and Hypothesis: Expression of neuronal nitric oxide synthase (nNOS) is decreased in the paraventricular nucleus (PVN) of rats with chronic heart failure (CHF), however the underlying molecular mechanism/s remain unclear. Recently, we demonstrated, Angiotensin II (Ang II) mediated increase in PIN: protein inhibitor of nNOS (0.76±0.10 Sham vs 1.12±0.09* CHF) which is known to down-regulate nNOS through disruption of active dimers (~60% decrease in dimer/monomer ratio) in the PVN of rats with CHF. Functionally impeded monomeric enzyme is degraded by ubiquitin proteasome system. Interestingly, PIN transcript levels remain unchanged in the PVN in CHF (1.00±0.23 Sham vs. 1.1±0.28 CHF). This observation prompted us to elucidate the molecular mechanism for the accumulation of PIN post-transcriptionally in the PVN in CHF Methods and Results: We used coronary artery ligation model of CHF in rats (6-8 weeks past ligation) and neuronal NG108-15 hybrid cell line. PIN translation was inhibited using cyclohexamide (CHX) for 0-4h after 20h of pretreatment with Ang II in NG108 cells. CHX mediated decrease in PIN expression was ameliorated with Ang II (0.19±0.04 vs 0.41±0.06* 4h). Proteasome inhibitor lactacystin (LC) treatment dramatically elevates PIN level suggesting the involvement of proteasome system in PIN regulation. Immunoprecipitation with ubiquitin antibody showed decrease PIN-Ub conjugates in Ang II-treated cells (1.04 ± 0.05 LC vs. 0.62 ± 0.07* LC AngII). In vitro ubiquitination assay in cells transfected with pCMV-(HA-Ub)8 vector revealed reduction of HA-Ub-PIN conjugates after Ang II treatment (9.2 ± 2.2 LC vs. 4.5 ± 0.6* LC Ang II). Furthermore, there was decreased accumulation of PIN-Ub conjugates in the PVN of CHF rats compared to Sham as revealed by immunohistochemistry. Conclusions: Taken together, our studies revealed that PIN is targeted for rapid degradation by the ubiquitin-proteasome pathway and Ang II delays the rate of degradation resulting in accumulation of PIN. We conclude that post-translational accumulation of PIN, mediated by Ang II, leads to a decrease in the dimeric active form of nNOS as well as protein levels of nNOS, which may lead to reduced nitric oxide resulting in over-activation of sympathetic drive during CHF.

ANG II in the paraventricular nucleus potentiates the cardiac sympathetic afferent reflex in rats with heart failure

2004 ◽  
Vol 97 (5) ◽  
pp. 1746-1754 ◽  
Author(s):  
Guo-Qing Zhu ◽  
Lie Gao ◽  
Kuashik P. Patel ◽  
Irving H. Zucker ◽  
Wei Wang
Keyword(s):  
Heart Failure ◽  
Electrical Stimulation ◽  
Paraventricular Nucleus ◽  
Sham Group ◽  
Ang Ii ◽  
Renal Sympathetic Nerve Activity ◽  
Afferent Nerves ◽  
Coronary Ligation ◽  
Cardiac Sympathetic Afferent Reflex ◽  
Renal Sympathetic

Chronic heart failure (CHF) is characterized by sympathoexcitation, and the cardiac sympathetic afferent reflex (CSAR) is a sympathoexcitatory reflex. Our previous studies have shown that the CSAR was enhanced in CHF. In addition, central angiotensin II (ANG II) is an important modulator of this reflex. This study was performed to determine whether the CSAR evoked by stimulation of cardiac sympathetic afferent nerves (CSAN) in rats with coronary ligation-induced CHF is enhanced by ANG II in the paraventricular nucleus (PVN). Under α-chloralose and urethane anesthesia, renal sympathetic nerve activity (RSNA) was recorded. The RSNA responses to electrical stimulation (5, 10, 20, and 30 Hz) of the CSAN were evaluated. Bilateral microinjection of the AT1-receptor antagonist losartan (50 nmol) into the PVN had no significant effects in the sham group, but it abolished the enhanced RSNA response to stimulation in the CHF group. Unilateral microinjection of three doses of ANG II (0.03, 0.3, and 3 nmol) into the PVN resulted in dose-related increases in the RSNA responses to stimulation. Although ANG II also potentiated the RSNA response to electrical stimulation in sham rats, the RSNA responses to stimulation after ANG II into the PVN in rats with CHF were much greater than in sham rats. The effects of ANG II were prevented by pretreatment with losartan into the PVN in CHF rats. These results suggest that the central gain of the CSAR is enhanced in rats with coronary ligation-induced CHF and that ANG II in the PVN augments the CSAR evoked by CSAN, which is mediated by the central angiotensin AT1 receptors in rats with CHF.

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