2007
DOI: 10.1016/j.ejheart.2007.07.004
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Reactive oxygen species in the paraventricular nucleus mediate the cardiac sympathetic afferent reflex in chronic heart failure rats

Abstract: 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 shamoperated rats, PVN microinjection of the superoxide anion scavengers tempol or tiron almost abolished the CSAR, but th… Show more

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Cited by 46 publications
(88 citation statements)
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“…We further hypothesize that tempol decreases blood pressure in S6c-induced hypertension by reducing ROS levels in sympathetic ganglia and thereby postganglionic sympathetic nerve activity. Previous studies have shown that tempol is, in fact, sympathoinhibitory in hypertensive rats (17,24). A caveat to this conclusion, however, is that tempol also has other pharmacological effects [e.g., opening large conductance, calcium activated potassium channels (64)] and sites of action (e.g., blood vessels, kidney or brain) that could attenuate sympathetic activity and/or hypertension.…”
Section: Discussionmentioning
confidence: 68%
“…We further hypothesize that tempol decreases blood pressure in S6c-induced hypertension by reducing ROS levels in sympathetic ganglia and thereby postganglionic sympathetic nerve activity. Previous studies have shown that tempol is, in fact, sympathoinhibitory in hypertensive rats (17,24). A caveat to this conclusion, however, is that tempol also has other pharmacological effects [e.g., opening large conductance, calcium activated potassium channels (64)] and sites of action (e.g., blood vessels, kidney or brain) that could attenuate sympathetic activity and/or hypertension.…”
Section: Discussionmentioning
confidence: 68%
“…The increased AT 1 receptors in the PVN were involved in the excessive sympathetic activation in CHF [40]. The super- oxide anions in the PVN mediated the effects Ang II in the PVN on sympathetic activation and the enhanced CSAR that partially contributes to the sympathetic activation in acute experiment of CHF rats [19]. Excessive production of superoxide anions and activation of the redox-regulated transcription factor activator protein-1 (AP-1) in the PVN implicated as key mediators in the pathogenesis of renovascular hypertension [2].…”
Section: Discussionmentioning
confidence: 95%
“…Microinjection of tempol, a superoxide dismutase (SOD) mimic, into the PVN inhibits the excessive sympathetic activation and CSAR in the acute experiment of rats with CHF [19]. The central SOD1, an antioxidant isoenzyme, which catalyzes the conversion of superoxide anions into hydrogen peroxides, plays an important role in the modulation of sympathetic nerve activity [17].…”
Section: Introductionmentioning
confidence: 99%
“…administration of losartan, an angiotensin II (Ang II) AT1 receptor antagonist, triggers a selective increase in sensitivity for renal sympathoinhibitory reflex responses in the renovascular hypertension model (Campos et al, 2017). The production of Ang II-mediated ROS is widely described in the literature (Seshiah et al, 2002;Han et al, 2007), therefore, it is reasonable to hypothesize that the baroreceptor dysfunction found in the respective hypertension model is evoked, in part, by a prooxidative spinal angiotensinergic action. However, further studies are needed to clarify the origin of spinal ROS, its topographic location, as well as the precursor agents involved in its synthesis.…”
Section: Effects Of Intrathecal Administration Of Tempolmentioning
confidence: 99%
“…Previous studies point to the involvement of reactive oxygen species (ROS) in cardiovascular diseases, and it seems to be an important molecular target to attenuate the systemic effects evoked by such disorders (Han et al, 2007;Nishi et al, 2013). Furthermore, evidence indicates that ROS, when in excess on the system, have the ability to influence baroreflex by attenuating the mechanism sensitivity, suggesting that the existence of oxidative balance is crucial for normal reflex activity Campos et al, 2015).…”
Section: Introduction Spinal Reactive Oxygen Species Contributes To Rmentioning
confidence: 99%