ORCID Profile
0000-0002-2937-575X
Current Organisations
University of Tennessee Health Science Center
,
Universidade Federal de São Paulo
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2017
Publisher: American Physiological Society
Date: 08-2019
DOI: 10.1152/AJPREGU.00228.2018
Abstract: Catheter-based renal denervation (RDN) was introduced as a treatment for resistant hypertension. There remain critical questions regarding the physiological mechanisms underlying the hypotensive effects of catheter-based RDN. Previous studies indicate that surgical denervation reduces renin and the natriuretic response to saline loading however, the effects on these variables of catheter-based RDN, which does not yield complete denervation, are largely unknown. The aim of this study was to investigate the effects of catheter-based RDN on glomerular-associated renin and regulation of fluid and sodium homeostasis in response to physiological challenges. First, immunohistochemical staining for renin was performed in normotensive sheep (
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2021
DOI: 10.1161/HYPERTENSIONAHA.120.16054
Abstract: A growing number of clinical studies suggest that in heart failure renal denervation (RDN) has beneficial effects on the autonomic control of the heart. There is also experimental evidence that surgical RDN improves sodium handling and clearance in heart failure. The aim of this study was to determine the effects of catheter-based RDN on the sympathetic and parasympathetic control of the heart, and salt and water handling capacity of the kidneys, in sheep with established heart failure. A randomized, controlled study was conducted in 10 sheep with heart failure (ejection fraction %) induced by rapid ventricular pacing. Sheep underwent either bilateral RDN using the Symplicity denervation system or sham denervation and were studied 1 and 6 weeks after RDN. In established ovine heart failure, at 6 weeks after catheter-based RDN, heart rate significantly decreased, estimates of resting and maximal parasympathetic control of heart rate increased, and cardiac sympathetic nerve activity decreased. Compared with sham denervation, there was an increase in the resting sodium and water excretion 6 weeks after catheter-RDN and an improved ability of the kidneys to excrete a nonhypertensive saline load. After catheter-based RDN, renal norepinephrine levels were reduced by 70% compared with sham denervation. In established heart failure, RDN induced a beneficial shift in both arms of the autonomic nervous control of the heart and improved the ability of the kidneys to excrete sodium and water. Thus, effective catheter-based RDN may be beneficial to both the heart and kidneys in heart failure.
Publisher: American Physiological Society
Date: 15-04-2015
DOI: 10.1152/AJPRENAL.00515.2014
Abstract: Renal nerve stimulation at a low frequency (below 2 Hz) causes water and sodium reabsorption via α 1 -adrenoreceptor tubular activation, a process independent of changes in systemic blood pressure, renal blood flow, or glomerular filtration rate. However, the underlying mechanism of the reabsorption of sodium is not fully understood. Since the sympathetic nervous system and intrarenal ANG II appear to act synergistically to mediate the process of sodium reabsorption, we hypothesized that low-frequency acute electrical stimulation of the renal nerve (ESRN) activates NHE3-mediated sodium reabsorption via ANG II AT 1 receptor activation in Wistar rats. We found that ESRN significantly increased urinary angiotensinogen excretion and renal cortical ANG II content, but not the circulating angiotensinogen levels, and also decreased urinary flow and pH and sodium excretion via mechanisms independent of alterations in creatinine clearance. Urinary cAMP excretion was reduced, as was renal cortical PKA activity. ESRN significantly increased NHE3 activity and abundance in the apical microvillar domain of the proximal tubule, decreased the ratio of phosphorylated NHE3 at serine 552/total NHE3, but did not alter total cortical NHE3 abundance. All responses mediated by ESRN were completely abolished by a losartan-mediated AT 1 receptor blockade. Taken together, our results demonstrate that higher NHE3-mediated proximal tubular sodium reabsorption induced by ESRN occurs via intrarenal renin angiotensin system activation and triggering of the AT 1 receptor/inhibitory G-protein signaling pathway, which leads to inhibition of cAMP formation and reduction of PKA activity.
Publisher: Canadian Science Publishing
Date: 02-2012
DOI: 10.1139/Y11-120
Abstract: The birdseed Phalaris canariensis (Pc) is popularly used as an antihypertensive agent. The aqueous extract of Pc (AEPc) was administered in adult normotensive Wistar rats and spontaneously hypertensive rats (SHR) and in prehypertensive young SHR (SHR Y , 3 weeks old). Animals received AEPc (400 mg·kg –1 ·day –1 , by gavage) for 30 days, then groups were ided into 2 subgroups: one was treated for another 30 days and the other received water instead of AEPc for 30 days. AEPc reduced systolic blood pressure (SBP) in both adult groups however, treatment interruption was followed by a gradual return of the SBP to baseline levels. SHR Y became hypertensive 30 days after weaning. AEPc minimized the increase in SBP in SHR Y , but blood pressure rose to levels similar to those in the untreated group with treatment interruption. There were no changes in renal function, diuresis, or Na + excretion. Pc is rich in tryptophan, and the inhibition of the metabolism of tryptophan to kynurenine, a potential vasodilator factor, prevented the blood pressure reducing effect of AEPc. Moreover, AEPc significantly reduced sympathoexcitation. Data indicate that the metabolic derivative of tryptophan, kinurenine, may be a mediator of the volume-independent antihypertensive effect of Pc, which was at least in part mediated by suppression of the sympathetic tonus.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.AUTNEU.2017.01.003
Abstract: Presympathetic neurons in the rostral ventrolateral medulla (RVLM) including the adrenergic cell groups play a major role in the modulation of several reflexes required for the control of sympathetic vasomotor tone and blood pressure (BP). Moreover, sympathetic vasomotor drive to the kidneys influence natriuresis and diuresis by inhibiting the cAMP/PKA pathway and redistributing the Na
Publisher: Nativa
Date: 15-07-2021
DOI: 10.31413/NATIVA.V9I3.10141
Abstract: Uma técnica muito utilizada para recuperação de áreas degradadas é o plantio de mudas, uma espécie que apresenta um grande potencial é o Mulungu. Além disso, na recuperação de áreas degradadas se faz necessário o uso de fertilizantes para o solo, assim a produção de fertilizantes por meio de compostagem, mostra-se uma técnica sustentável e de baixo custo. O objetivo deste trabalho foi analisar a eficiência da fertilização pelo material proveniente de compostagem seguido por vermicompostagem no cultivo de plantas de Mulungu. Realizou-se um experimento, na casa de vegetação do IFCE c us Maracanaú, utilizando diferentes substratos: 100% areia (em volume), 50% húmus comercial, 100% húmus comercial, 50% composto orgânico, 75% composto orgânico e 100% composto orgânico. As plantas foram coletadas e foram analisadas: as produções de matéria fresca e seca e a quantificação dos teores de solutos orgânicos. Verificou-se que o crescimento das plantas e a produção de solutos orgânicos estão ligados diretamente ao teor de nitrogênio no solo, de forma que a escassez de nitrogênio é um fator limitante para o adequado crescimento do Mulungu. Nas condições experimentais empregadas, verificou-se que o tratamento contendo 75% composto orgânico ocasionou o maior crescimento das plantas de Mulungu.Palavras-chave: nutrientes, nitrogênio, solutos orgânicos, matéria fresca, matéria seca.
Publisher: Wiley
Date: 07-2019
DOI: 10.14814/PHY2.14183
Publisher: Canadian Science Publishing
Date: 08-2021
Abstract: Chronic nicotine exposure may increase cardiovascular risk by impairing the cardiac autonomic function. Besides, physical exercise (PE) has shown to improve cardiovascular health. Thus, we aimed to investigate the effects of PE on baroreflex sensitivity (BRS), heart rate variability (HRV), and sympathetic nerve activity (SNA) in chronically nicotine-exposed rats. Male Wistar rats were assigned to four independent groups: Control (treated with saline solution), Control+Ex (treated with saline and submitted to treadmill training), Nicotine (treated with Nicotine), and Nicotine+Ex (treated with nicotine and submitted to treadmill training). Nicotine (1 mg·kg −1 ) was administered daily for 28 consecutive days. PE consisted of running exercise (60%–70% of maximal aerobic capacity) for 45 min, 5 days per week, for 4 weeks. At the end of the protocol, cardiac BRS, HRV, renal SNA (rSNA), and renal BRS were assessed. Nicotine treatment decreased absolute values of HRV indexes, increased low frequency/high frequency ratio of HRV, reduced the bradycardic and sympatho-inhibitory baroreceptor reflex responses, and reduced the rSNA. PE effectively restored time-domain HRV indexes, the bradycardic and sympatho-inhibitory reflex responses, and the rSNA in chronic nicotine-treated rats. PE was effective in preventing the deterioration of time-domain parameters of HRV, arterial baroreceptor dysfunction, and the rSNA after nicotine treatment.
Publisher: Grupo Verde de Agroecologia e Abelhas
Date: 10-2019
DOI: 10.18378/RVADS.V14I4.6735
Abstract: O percolado de aterro sanitário é um líquido produzido a partir de processos físicos, químicos e biológicos aos quais os resíduos sólidos urbanos são submetidos nos aterros sanitários. Apresenta uma composição físico-química variável e pode conter altos teores de nutrientes, sendo assim empregado na fertilização de plantas. Por isso, objetivou-se avaliar o crescimento de plantas de girassol irrigadas com água de moderada salinidade e com suplementação nutricional com percolado de aterro sanitário. O experimento foi conduzido em área experimental com cobertura de nylon (sombrite), sob delineamento inteiramente casualizado em um fatorial 4 x 2, sendo [1: 100% de areia de granulometria fina - NBR 6502 2: areia + adubo/fertilizante orgânico misto (mistura de bagaço de cana, esterco bovino, esterco de galinha, serragem de madeira e gesso agrícola) e 80 kg de N ha-1, 3: areia + percolado de aterro sanitário e 80 kg de N ha-1 e 4: areia + percolado de aterro sanitário e 160 kg de N ha-1] e duas concentrações salinas da água de irrigação [irrigação com água destilada ou solução de NaCl a 60 mM], com 10 repetições, em vasos de 12 L. Foram realizadas análises de crescimento (altura, diâmetro do coleto, número de folhas), teores relativos de clorofila e diâmetro dos capítulos. Nas condições experimentais empregadas, substrato arenoso, as concentrações de percolado de aterro sanitário utilizadas promoveram incrementos em todas as variáveis de crescimento analisadas nas plântulas de girassol, especialmente a 80 Kg N ha-1. A irrigação com solução de NaCl a 60 mM não ocasionou efeitos negativos nas variáveis de crescimento, demonstrando assim a tolerância moderada das plantas de girassol à salinidade em substrato arenoso.
Publisher: MDPI AG
Date: 26-12-2022
DOI: 10.3390/IJMS24010349
Abstract: We examined the effects of an acute increase in blood pressure (BP) and renal sympathetic nerve activity (rSNA) induced by bicuculline (Bic) injection in the paraventricular nucleus of hypothalamus (PVN) or the effects of a selective increase in rSNA induced by renal nerve stimulation (RNS) on the renal excretion of sodium and water and its effect on sodium-hydrogen exchanger 3 (NHE3) activity. Uninephrectomized anesthetized male Wistar rats were ided into three groups: (1) Sham (2) Bic PVN: (3) RNS + Bic injection into the PVN. BP and rSNA were recorded, and urine was collected prior and after the interventions in all groups. RNS decreased sodium (58%) and water excretion (53%) independently of BP changes (p 0.05). However, after Bic injection in the PVN during RNS stimulation, the BP and rSNA increased by 30% and 60% (p 0.05), respectively, diuresis (5-fold) and natriuresis (2.3-fold) were increased (p 0.05), and NHE3 activity was significantly reduced, independently of glomerular filtration rate changes. Thus, an acute increase in the BP overcomes RNS, leading to diuresis, natriuresis, and NHE3 activity inhibition.
Publisher: Springer Science and Business Media LLC
Date: 17-07-2019
DOI: 10.1038/S41440-019-0301-Z
Abstract: Sympathetic overactivation contributes to the pathogenesis of both experimental and human hypertension. We have previously reported that oxidative stress in sympathetic premotor neurons leads to arterial baroreflex dysfunction and increased sympathetic drive to the kidneys in an experimental model of neurogenic hypertension. In this study, we hypothesized that melatonin, a potent antioxidant, may be protective in the brainstem regions involved in the tonic and reflex control of blood pressure (BP) in renovascular hypertensive rats. Neurogenic hypertension was induced by placing a silver clip (gap of 0.2 mm) around the left renal artery, and after 5 weeks of renal clip placement, the rats were treated orally with melatonin (30 mg/kg/day) by gavage for 15 days. At the end of melatonin treatment, we evaluated baseline mean arterial pressure (MAP), renal sympathetic nerve activity (rSNA), and the baroreflex control of heart rate (HR) and rSNA. Reactive oxygen species (ROS) were detected within the brainstem regions by dihydroethidium staining. Melatonin treatment effectively reduced baseline MAP and sympathoexcitation to the ischemic kidney in renovascular hypertensive rats. The baroreflex control of HR and rSNA were improved after melatonin treatment in the hypertensive group. Moreover, there was a preferential decrease in ROS within the rostral ventrolateral medulla (RVLM) and the nucleus of the solitary tract (NTS). Therefore, our study indicates that melatonin is effective in reducing renal sympathetic overactivity associated with decreased ROS in brainstem regions that regulate BP in an experimental model of neurogenic hypertension.
Publisher: Elsevier BV
Date: 09-2023
Publisher: Wiley
Date: 05-2015
DOI: 10.1113/EP085075
Publisher: Public Library of Science (PLoS)
Date: 25-02-2016
Location: United States of America
Location: Brazil
Location: United States of America
Start Date: 2016
End Date: 2016
Funder: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
View Funded ActivityStart Date: 2017
End Date: 2020
Funder: Fundação de Amparo à Pesquisa do Estado de São Paulo
View Funded ActivityStart Date: 2017
End Date: 2018
Funder: Fundação de Amparo à Pesquisa do Estado de São Paulo
View Funded Activity