Differential effects of renal denervation on arterial baroreceptor function in Goldblatt hypertension model

Lincevicius, Gisele S.; Shimoura, Caroline Gusson; Nishi, Érika E.; Oliveira, Tales Lyra de; Cespedes, Juliana Garcia; Bergamaschi, Cássia T.; Campos, Rui

doi:10.1016/j.autneu.2017.06.002

Cited by 12 publications

(6 citation statements)

References 35 publications

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“…In these rats, the left kidney is exposed to high and the right kidney to low BP with putatively different degrees of renal inflammation. We also investigated DRG neuron samples from denervated and clipped left kidneys from 2K1C animals since renal denervation in animal models of renovascular hypertension suggests involvement of renal nerves in the pathophysiology of this form of secondary hypertension [30,31]. Even selective afferent denervation alone had a significant influence on experimental renovascular hypertension [33,36].…”

Section: Introductionmentioning

confidence: 99%

Responsiveness of afferent renal nerve units in renovascular hypertension in rats

Rodionova

Hilgers

Rafii-Tabrizi

et al. 2021

Pflugers Arch - Eur J Physiol

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Previous data suggest that renal afferent nerve activity is increased in hypertension exerting sympathoexcitatory effects. Hence, we wanted to test the hypothesis that in renovascular hypertension, the activity of dorsal root ganglion (DRG) neurons with afferent projections from the kidneys is augmented depending on the degree of intrarenal inflammation. For comparison, a nonhypertensive model of mesangioproliferative nephritis was investigated. Renovascular hypertension (2-kidney, 1-clip [2K1C]) was induced by unilateral clipping of the left renal artery and mesangioproliferative glomerulonephritis (anti-Thy1.1) by IV injection of a 1.75-mg/kg BW OX-7 antibody. Neuronal labeling (dicarbocyanine dye [DiI]) in all rats allowed identification of renal afferent dorsal root ganglion (DRG) neurons. A current clamp was used to characterize neurons as tonic (sustained action potential [AP] firing) or phasic (1–4 AP) upon stimulation by current injection. All kidneys were investigated using standard morphological techniques. DRG neurons exhibited less often tonic response if in vivo axonal input from clipped kidneys was received (30.4% vs. 61.2% control, p < 0.05). However, if the nerves to the left clipped kidneys were cut 7 days prior to investigation, the number of tonic renal neurons completely recovered to well above control levels. Interestingly, electrophysiological properties of neurons that had in vivo axons from the right non-clipped kidneys were not distinguishable from controls. Renal DRG neurons from nephritic rats also showed less often tonic activity upon current injection (43.4% vs. 64.8% control, p < 0.05). Putative sympathoexcitatory and impaired sympathoinhibitory renal afferent nerve fibers probably contribute to increased sympathetic activity in 2K1C hypertension.

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Section: Introductionmentioning

confidence: 99%

Responsiveness of afferent renal nerve units in renovascular hypertension in rats

Rodionova

Hilgers

Rafii-Tabrizi

et al. 2021

Pflugers Arch - Eur J Physiol

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“…In previous studies, we showed that DAx of the ischemic kidney reduced BP partially and decreased sympathetic hyperactivity to both the ischemic and contralateral kidneys (Lopes et al, 2020) and that the total renal denervation improved cardiac and renal, but not lumbar, baroreflex sensitivity in 2K1C rats (Lincevicius et al, 2017). Interestingly, in the present study, we show that renal DAx improves the reflex control of HR by arterial baroreceptors in the 2K1C model, potentially due to the modulatory influence of renal sensory fibers that project to regions involved in the control of baroreflex function, such as the nucleus tractus solitarii, PVN, and RVLM, differently influencing the control of sympathetic vasomotor outflow (Solano-Flores et al, 1997;Xu et al, 2015;Nishi et al, 2017).…”

Section: Discussionmentioning

confidence: 83%

“…and sodium nitroprusside (5, 12 e 20 μg/rat, i.v. ; Sigma Aldrich Co, St. Louis, MO, United States) were measured, as previously reported (Lincevicius et al, 2017). Cardiac baroreflex sensitivity was evaluated by the mean index relating changes in HR to the changes in MAP and expressed as beats per mmHg (bpm/ mmHg, baroreflex function sensitivity).…”

Section: Direct Measurement Of Blood Pressure and Heart Rate And Baromentioning

confidence: 99%

Renal Sensory Activity Regulates the γ-Aminobutyric Acidergic Inputs to the Paraventricular Nucleus of the Hypothalamus in Goldblatt Hypertension

et al. 2020

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Renal sensory activity is centrally integrated within brain nuclei involved in the control of cardiovascular function, suggesting that renal afferents regulate basal and reflex sympathetic vasomotor activity. Evidence has shown that renal deafferentation (DAx) evokes a hypotensive and sympathoinhibitory effect in experimental models of cardiovascular diseases; however, the underlying mechanisms involved in this phenomenon need to be clarified, especially those related to central aspects. We aimed to investigate the role of renal afferents in the control of γ-aminobutyric acid (GABA)ergic inputs to the paraventricular nucleus (PVN) of the hypothalamus in renovascular hypertensive (2K1C) rats and their influence in the regulation of cardiovascular function. Hypertension was induced by clipping the left renal artery. After 4 weeks, renal DAx was performed by exposing the left renal nerve to a 33 mM capsaicin solution for 15 min. After 2 weeks of DAx, microinjection of muscimol into the PVN was performed in order to evaluate the influence of GABAergic activity in the PVN and its contribution to the control of renal sympathetic nerve activity (rSNA) and blood pressure (BP). Muscimol microinjected into the PVN triggered a higher drop in BP and rSNA in the 2K1C rats and renal DAx mitigated these responses. These results suggest that renal afferents are involved in the GABAergic changes found in the PVN of 2K1C rats. Although the functional significance of this phenomenon needs to be clarified, it is reasonable to speculate that GABAergic alterations occur to mitigate microglia activation-induced sympathoexcitation in the PVN of 2K1C rats.

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“…Additional evidence that suggests a relation between apneainduced hypoxia and hypertension and sympathetic activation comes from the finding that acute hyperoxia reduces blood pressure and sympathetic activity in apnea patients but not in obese normotensive controls (25). However, arterial chemoreflexes are also increased in hypertensive patients that do not have OSA (37).…”

Section: Discussionmentioning

confidence: 99%

“…The background noise was then subtracted from the rectified and integrated signal, and the baseline value for each animal was set at 100% (18,40). To quantify the spike rate at rest, we used the average number of spikes per second from a 60-s segment of the raw signal and counted the number of spikes above the level of the background noise with the spike histogram module from LabChart (version 8.0.2) (25,47). To examine cardiac coupling of sympathetic activity at rest, we used a power spectrum analysis (3,27).…”

Section: Analysis Of Sympathetic Nerve Activitymentioning

confidence: 99%

Increased sympathetic responses induced by chronic obstructive sleep apnea are caused by sleep fragmentation

Ferreira

Schoorlemmer

Rocha

et al. 2020

Journal of Applied Physiology

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Obstructive sleep apnea causes a hyperactive chemoreflex, with increased sympathetic activation. However, it is not clear whether this pathophysiologic mechanism is due to repeated hypoxia or to sleep disruption. The present study suggests that sleep fragmentation contributes importantly to increased sympathetic activation after chemoreceptor stimulation. This suggests that sleep fragmentation has an important role in the sympathetic activation seen in sleep apnea patients.

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Differential effects of renal denervation on arterial baroreceptor function in Goldblatt hypertension model

Cited by 12 publications

References 35 publications

Responsiveness of afferent renal nerve units in renovascular hypertension in rats

Responsiveness of afferent renal nerve units in renovascular hypertension in rats

Renal Sensory Activity Regulates the γ-Aminobutyric Acidergic Inputs to the Paraventricular Nucleus of the Hypothalamus in Goldblatt Hypertension

Increased sympathetic responses induced by chronic obstructive sleep apnea are caused by sleep fragmentation

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