Time-dependent changes in autonomic control of splanchnic vascular resistance and heart rate in ANG II-salt hypertension

Kuroki, Marcos T.; Guzmán, P.; Fink, Gregory D.; Osborn, John W.

doi:10.1152/ajpheart.00930.2011

Cited by 29 publications

(44 citation statements)

References 27 publications

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“…5) has the disadvantage that arterial BP falls rapidly, producing changes in arterial diameter that are probably the result of both decreased SNA to the artery and decreased distending forces. In Ang II-salt hypertension also, an increased 'depressor' (decrease in mean arterial BP) response to systemic block of autonomic ganglionic transmission can be demonstrated (Kuroki et al 2012), suggesting increased SNA-induced vascular tone. In contrast, local application of sympathetic neurotransmitter receptor blockers (Figs.…”

Section: Sympathetic Nerve Activitymentioning

confidence: 97%

“…These results suggest that V 1A receptor activation by endogenous AVP had a negligible effect on the increased FA tone of Ang II-infused mice. Acute blockade of autonomic ganglionic transmission causes a larger fall in mean arterial BP, a 'depressor' response, in Ang II-infused animals compared to controls (Kuroki et al 2012). Thus, increased arterial pressure after Ang II treatment involves increased SNA, or increased efficacy of SNA, as might be the result of increased 'vascular reactivity' (Anning et al 2005;Touyz et al 2005;Ding et al 2007;Hercule et al 2007;Kirabo et al 2011;Kharade et al 2013).…”

Section: Local Vascular Ang II Receptor Activation Mediates a Small Cmentioning

confidence: 99%

“…Chronic systemic Ang II infusion induces experimental hypertension, which involves numerous changes in the CNS (Zimmerman et al 2004;Kuroki et al 2012;Young et al 2012), immune system (Guzik et al 2007;Marvar et al 2010), cardiovascular system (Kim & Iwao, 2000;Touyz et al 2005;Ding et al 2007;Hercule et al 2007;Kirabo et al 2011;Kharade et al 2013), and the peripheral salt and water regulation organs, including the kidneys (Kim & Iwao, 2000;Bek et al 2006;Gonzalez-Villalobos et al 2009;Navar, 2010). Increased central SNA has been implicated in various hypertension models, particularly in models involving Ang II (Zimmerman et al 2004;Marvar et al 2010;Yoshimoto et al 2010;Kuroki et al 2012;Young et al 2012). A vigorous debate has focused recently on the relative importance of the sympathetic nervous system vs. the kidneys (Esler et al 2010;Navar, 2010) in essential hypertension.…”

Section: Relation To Hypertensionmentioning

confidence: 99%

“…The increased SNA is thought to be region-specific, and to vary during experimental hypertension (Yoshimoto et al 2010;Kuroki et al 2012). Also, increased SNA has been postulated to be regulated by both fast and slow signalling pathways in Ang II/salt hypertensions Gabor & Leenen, 2012).…”

Section: Relation To Hypertensionmentioning

confidence: 99%

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Intravital Förster resonance energy transfer imaging reveals elevated [Ca²⁺]_i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Wang¹,

Chen

Wier³

et al. 2013

The Journal of Physiology

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Key points• It is desirable to study altered artery function in hypertension in living animals, where factors influencing artery function are intact.• We infused 'biosensor' mice chronically with angiotensin II to produce hypertension, and used intravital Förster resonance energy transfer microscopy to measure, simultaneously, [Ca 2+ ] i and artery diameter in vivo.• Femoral arteries in hypertensive mice had increased basal (resting) [Ca 2+ ] i and were more constricted than femoral arteries in saline-infused mice. These differences were abolished by blocking (1) all peripheral sympathetic nerve activity (SNA), or (2) vascular α 1 -adrenoceptors, but not by blocking vascular angiotensin II or arginine vasopressin receptors.• Neither contractility nor structural changes were found in femoral arteries of angiotensin II-infused mice.• The results support previous suggestions that angiotensin II infusion raises blood pressure by acting on the CNS to increase SNA, which increases smooth muscle [Ca 2+ ] i . Infused angiotensin II does not act directly on arterial angiotensin II receptors.Abstract Artery narrowing in hypertension can only result from structural remodelling of the artery, or increased smooth muscle contraction. The latter may occur with, or without, increases in [Ca 2+ ] i . Here, we sought to measure, in living hypertensive mice, possible changes in artery dimensions and/or [Ca 2+ ] i , and to determine some of the mechanisms involved. Ca 2+ /calmodulin biosensor (Förster resonance energy transfer-based) mice were made hypertensive by S.C. infusion of angiotensin II (Ang II, 400 ng kg −1 min −1 , 2-3 weeks). Intravital fluorescence microscopy was used to determine [Ca 2+ ] i and outer diameter of surgically exposed, intact femoral artery (FA) of anaesthetized mice. Active contractile FA 'tone' was calculated from the basal-state diameter and the passive (i.e. Ca 2+ -free) diameter (PD). Compared to saline control, FAs of Ang II-infused mice had (1) ∼21% higher active tone and (2) ∼78 nM higher smooth muscle [Ca 2+ ] i , but (3)

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Section: Sympathetic Nerve Activitymentioning

confidence: 97%

Section: Local Vascular Ang II Receptor Activation Mediates a Small Cmentioning

confidence: 99%

Section: Relation To Hypertensionmentioning

confidence: 99%

Section: Relation To Hypertensionmentioning

confidence: 99%

See 2 more Smart Citations

Intravital Förster resonance energy transfer imaging reveals elevated [Ca²⁺]_i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Wang¹,

Chen

Wier³

et al. 2013

The Journal of Physiology

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“…Emerging evidence suggests that chronic activation of the sympathetic nervous system can occur in a disease-specific pattern or sympathetic signature (33). For example, in the ovine pacing-induced model of heart failure, sympathetic activity to the heart is increased, but rSNA is normal (44).…”

Section: Effect Of Organ/region-specific Denervation On the Pressor Rmentioning

confidence: 99%

Effect of global and regional sympathetic blockade on arterial pressure during water deprivation in conscious rats

Veitenheimer

Engeland²,

Guzmán

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

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Veitenheimer BJ, Engeland WC, Guzman PA, Fink GD, Osborn JW. Effect of global and regional sympathetic blockade on arterial pressure during water deprivation in conscious rats. Am J Physiol Heart Circ Physiol 303: H1022-H1034, 2012. First published August 17, 2012; doi:10.1152/ajpheart.00413.2012.-Forty-eight hours of water deprivation (WD) in conscious rats results in a paradoxical increase in mean arterial pressure (MAP). Previous studies suggest this may be due to increased sympathetic nerve activity (SNA). However, this remains to be investigated in conscious, freely behaving animals. The purpose of this study was to determine, in conscious rats, the role of the sympathetic nervous system (SNS) in mediating WD-induced increases in MAP and to identify which vascular beds are targeted by increased SNA. Each rat was chronically instrumented with a radiotelemetry transmitter to measure MAP and heart rate (HR) and an indwelling venous catheter for plasma sampling and/or drug delivery. MAP and HR were continuously measured during a 2-day baseline period followed by 48 h of WD and then a recovery period. By the end of the WD period, MAP increased by ϳ15 mmHg in control groups, whereas HR did not change significantly. Chronic blockade of ␣ 1/␤1-adrenergic receptors significantly attenuated the WD-induced increase in MAP, suggesting a role for global activation of the SNS. However, the MAP response to WD was unaffected by selective denervations of the hindlimb, renal, or splanchnic vascular beds, or by adrenal demedullation. In contrast, complete adrenalectomy (with corticosterone and aldosterone replaced) significantly attenuated the MAP response to WD in the same time frame as ␣ 1/␤1-adrenergic receptor blockade. These results suggest that, in conscious water-deprived rats, the SNS contributes to the MAP response and may be linked to release of adrenocortical hormones. Finally, this sympathetically mediated response is not dependent on increased SNA to one specific vascular bed. osmolality; sympathetic nerve activity; water deprivation; denervation; adrenal cortex WATER DEPRIVATION (WD) over long periods of time increases plasma osmolality and decreases blood volume. Despite the hypovolemia induced by WD, it has been reported that mean arterial pressure (MAP) is not only maintained but actually increases in conscious rats (4,8,46). The mechanisms mediating this paradoxical increase in MAP are not clear, but previous studies have shown that WD is accompanied by elevations in the renin-angiotensin-aldosterone system (4, 14, 16), plasma vasopressin and corticosterone (14,17,32), and sympathetic nerve activity (SNA) (10,53,55,56). In this study, we investigated the sympathetic component of the MAP response to WD.Although it is generally accepted that the sympathetic nervous system is activated during WD to support MAP, the evidence supporting this is not entirely conclusive. Studies in which plasma norepinephrine was measured as an indicator of global sympathetic activity have been inconsistent, with some showing no ch...

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Physical (in)activity‐dependent structural plasticity in bulbospinal catecholaminergic neurons of rat rostral ventrolateral medulla

Mischel

Llewellyn‐Smith

Mueller

2013

J of Comparative Neurology

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Increased activity of the sympathetic nervous system is thought to play a role in the development and progression of cardiovascular disease. Recent work has shown that physical inactivity versus activity alters neuronal structure in brain regions associated with cardiovascular regulation. Our physiological studies suggest that neurons in the rostral ventrolateral medulla (RVLM) are more responsive to excitation in sedentary versus physically active animals. We hypothesized that enhanced functional responses in the RVLM may be due, in part, to changes in the structure of RVLM neurons that control sympathetic activity. We used retrograde tracing and immunohistochemistry for tyrosine hydroxylase (TH) to identify bulbospinal catecholaminergic (C1) neurons in sedentary and active rats after chronic voluntary wheel-running exercise. We then digitally reconstructed their cell bodies and dendrites at different rostrocaudal levels. The dendritic arbors of spinally-projecting TH neurons from sedentary rats were more branched than those of physically active rats (p<0.05). In sedentary rats, dendritic branching was greater in more rostral versus more caudal bulbospinal C1 neurons whereas, in physically active rats, dendritic branching was consistent throughout the RVLM. In contrast, cell body size and the number of primary dendrites did not differ between active and inactive animals. We suggest that these structural changes provide an anatomical underpinning for the functional differences observed in our in vivo studies. These inactivity-related structural and functional changes enhance the overall sensitivity of RVLM neurons to excitatory stimuli and may contribute to an increased risk of cardiovascular disease in sedentary individuals.

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Time-dependent changes in autonomic control of splanchnic vascular resistance and heart rate in ANG II-salt hypertension

Cited by 29 publications

References 27 publications

Intravital Förster resonance energy transfer imaging reveals elevated [Ca²⁺]_i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Intravital Förster resonance energy transfer imaging reveals elevated [Ca²⁺]_i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Effect of global and regional sympathetic blockade on arterial pressure during water deprivation in conscious rats

Physical (in)activity‐dependent structural plasticity in bulbospinal catecholaminergic neurons of rat rostral ventrolateral medulla

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Time-dependent changes in autonomic control of splanchnic vascular resistance and heart rate in ANG II-salt hypertension

Cited by 29 publications

References 27 publications

Intravital Förster resonance energy transfer imaging reveals elevated [Ca2+]i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Intravital Förster resonance energy transfer imaging reveals elevated [Ca2+]i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Effect of global and regional sympathetic blockade on arterial pressure during water deprivation in conscious rats

Physical (in)activity‐dependent structural plasticity in bulbospinal catecholaminergic neurons of rat rostral ventrolateral medulla

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Intravital Förster resonance energy transfer imaging reveals elevated [Ca²⁺]_i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice

Intravital Förster resonance energy transfer imaging reveals elevated [Ca²⁺]_i and enhanced sympathetic tone in femoral arteries of angiotensin II‐infused hypertensive biosensor mice