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Favero AM, Rosales TO, Scheschowitsch K, Gonçalves MC, Benedet PO, Sordi R, Nardi GM, Assreuy J. Blockade of sympathetic ganglia improves vascular dysfunction in septic shock. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:6551-6562. [PMID: 38457039 DOI: 10.1007/s00210-024-03032-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 02/28/2024] [Indexed: 03/09/2024]
Abstract
Sepsis/septic shock activates the sympathetic nervous system (SNS) to deal with the infection stress. However, an imbalanced or maladaptive response due to excessive or uncontrolled activation characterizes autonomic dysfunction. Our hypothesis was that reducing this excessive activation of the autonomic nervous system would impact positively in sepsis. Using ganglionic blockers as a pharmacological approach, the main aim of the present report was to assess the role of ganglionic transmission in the vascular dysfunction associated with sepsis.Sepsis was induced in rats by cecal ligation and puncture (CLP). One hour after CLP surgery, rats were treated subcutaneously with hexamethonium (15 mg/kg; ganglionic blocker), pentolinium (5 mg/kg; a blocker with a higher selectivity for sympathetic ganglia compared to hexamethonium), or vehicle (PBS). Basal blood pressure and the response to adrenergic agonists were evaluated at 6 and 24 h after CLP surgery. Reactivity to vasoconstrictors, nitric oxide (NO) synthase 2 (NOS-2) expression, IL-1 and TNF plasma levels, and density of α1 adrenergic receptors were evaluated in the aorta 24 h after CLP.Septic shock resulted in hypotension and hyporesponsiveness to norepinephrine and phenylephrine, increased plasma cytokine levels and NOS-2 expression in the aorta, and decreased α1 receptor density in the same vessel. Pentolinium but not hexamethonium recovered responsiveness and α1 adrenergic receptor density in the aorta. Both blockers normalized the in vivo response to vasoconstrictors, and reduced plasma IL-1 and NOx levels and NOS-2 expression in the aorta.Blockade of ganglionic sympathetic transmission reduced the vascular dysfunction in experimental sepsis. This beneficial effect seems to be, at least in part, due to the preservation of α1 adrenergic receptor density and to reduced NOS-2 expression and may lead to adjuvant ways to treat human sepsis.
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MESH Headings
- Animals
- Shock, Septic/physiopathology
- Shock, Septic/drug therapy
- Shock, Septic/metabolism
- Male
- Ganglia, Sympathetic/drug effects
- Ganglia, Sympathetic/physiopathology
- Ganglia, Sympathetic/metabolism
- Ganglionic Blockers/pharmacology
- Rats, Wistar
- Nitric Oxide Synthase Type II/metabolism
- Rats
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-1/drug effects
- Blood Pressure/drug effects
- Tumor Necrosis Factor-alpha/metabolism
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- Ana Maria Favero
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | | | - Karin Scheschowitsch
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Muryel Carvalho Gonçalves
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Patricia Oliveira Benedet
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Regina Sordi
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Geisson Marcos Nardi
- Department of Morphological Sciences, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Jamil Assreuy
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil.
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2
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Jenkins ZM, Castle DJ, Eikelis N, Phillipou A, Lambert GW, Lambert EA. Autonomic nervous system function in women with anorexia nervosa. Clin Auton Res 2022; 32:29-42. [PMID: 34762216 DOI: 10.1007/s10286-021-00836-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/28/2021] [Indexed: 01/31/2023]
Abstract
PURPOSE Abnormalities in autonomic function have been observed in people with anorexia nervosa. However, the majority of investigations have utilised heart rate variability as the sole assessment of autonomic activity. The current study utilised a variety of methodologies to assess autonomic nervous system function in women with a current diagnosis of anorexia, a past diagnosis of anorexia who were weight-restored, and healthy controls. METHODS The sample included 37 participants: 10 participants with anorexia, 17 weight-restored participants (minimum body mass index > 18.5 for minimum of 12 months) and 10 controls. Assessments of autonomic function included muscle sympathetic nerve activity (MSNA) using microneurography, heart rate variability, baroreflex sensitivity, blood pressure variability, head-up tilt table test, sudomotor function and assessment of plasma catecholamines. RESULTS MSNA (bursts/min) was significantly decreased in both anorexia (10.22 ± 6.24) and weight-restored (17.58 ± 1.68) groups, as compared to controls (23.62 ± 1.01, p < 0.001 and p = 0.033, respectively). Participants with anorexia had a significantly lower standard deviation in heart rate, lower blood pressure variability and decreased sudomotor function as compared to controls. Weight-restored participants demonstrated decreased baroreflex sensitivity in response to head-up tilt as compared to controls. CONCLUSION Women with a current or previous diagnosis of anorexia have significantly decreased sympathetic activity, which may reflect a physiological response to decreased energy intake. During the state of starvation, women with anorexia also displayed decreased sudomotor function. The consequences of a sustained decrease in MSNA are unknown, and future studies should investigate autonomic function in long-term weight-restored participants to determine whether activity returns to normal.
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Affiliation(s)
- Zoe M Jenkins
- Iverson Health Innovation Research Institute and School of Health Sciences, Swinburne University of Technology, Melbourne, Australia. .,Department of Mental Health, St Vincent's Hospital Melbourne, PO Box 2900, Fitzroy, VIC, 3065, Australia. .,Department of Psychiatry, University of Melbourne, Melbourne, Australia.
| | - David J Castle
- Department of Mental Health, St Vincent's Hospital Melbourne, PO Box 2900, Fitzroy, VIC, 3065, Australia.,Centre for Complex Interventions, Centre for Addictions and Mental Health, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Nina Eikelis
- Iverson Health Innovation Research Institute and School of Health Sciences, Swinburne University of Technology, Melbourne, Australia
| | - Andrea Phillipou
- Department of Mental Health, St Vincent's Hospital Melbourne, PO Box 2900, Fitzroy, VIC, 3065, Australia.,Department of Psychiatry, University of Melbourne, Melbourne, Australia.,Centre for Mental Health and School of Health Sciences, Swinburne University of Technology, Melbourne, Australia.,Department of Mental Health, Austin Health, Melbourne, Australia
| | - Gavin W Lambert
- Iverson Health Innovation Research Institute and School of Health Sciences, Swinburne University of Technology, Melbourne, Australia
| | - Elisabeth A Lambert
- Iverson Health Innovation Research Institute and School of Health Sciences, Swinburne University of Technology, Melbourne, Australia
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3
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Levi DI, Wyrosdic JC, Hicks AI, Andrade MA, Toney GM, Prager-Khoutorsky M, Bourque CW. High dietary salt amplifies osmoresponsiveness in vasopressin-releasing neurons. Cell Rep 2021; 34:108866. [PMID: 33730577 PMCID: PMC8049100 DOI: 10.1016/j.celrep.2021.108866] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/13/2020] [Accepted: 02/24/2021] [Indexed: 12/28/2022] Open
Abstract
High dietary salt increases arterial pressure partly through activation of magnocellular neurosecretory cells (MNCVP) that secrete the antidiuretic and vasoconstrictor hormone vasopressin (VP) into the circulation. Here, we show that the intrinsic and synaptic excitation of MNCVP caused by hypertonicity are differentially potentiated in two models of salt-dependent hypertension in rats. One model combined salty chow with a chronic subpressor dose of angiotensin II (AngII-salt), the other involved replacing drinking water with 2% NaCl (salt loading, SL). In both models, we observed a significant increase in the quantal amplitude of EPSCs on MNCVP. However, model-specific changes were also observed. AngII-salt increased the probability of glutamate release by osmoreceptor afferents and increased overall excitatory network drive. In contrast, SL specifically increased membrane stiffness and the intrinsic osmosensitivity of MNCVP. These results reveal that dietary salt increases the excitability of MNCVP through effects on the cell-autonomous and synaptic osmoresponsiveness of MNCVP.
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Affiliation(s)
- David I Levi
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada
| | - Joshua C Wyrosdic
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada
| | - Amirah-Iman Hicks
- Department of Physiology, McGill University, 3644 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada
| | - Mary Ann Andrade
- Department of Cellular and Integrative Physiology, University of Texas Health Sciences Centre San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, University of Texas Health Sciences Centre San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Masha Prager-Khoutorsky
- Department of Physiology, McGill University, 3644 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada.
| | - Charles W Bourque
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada.
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4
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Osborn JW, Tyshynsky R, Vulchanova L. Function of Renal Nerves in Kidney Physiology and Pathophysiology. Annu Rev Physiol 2021; 83:429-450. [PMID: 33566672 DOI: 10.1146/annurev-physiol-031620-091656] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Renal sympathetic (efferent) nerves play an important role in the regulation of renal function, including glomerular filtration, sodium reabsorption, and renin release. The kidney is also innervated by sensory (afferent) nerves that relay information to the brain to modulate sympathetic outflow. Hypertension and other cardiometabolic diseases are linked to overactivity of renal sympathetic and sensory nerves, but our mechanistic understanding of these relationships is limited. Clinical trials of catheter-based renal nerve ablation to treat hypertension have yielded promising results. Therefore, a greater understanding of how renal nerves control the kidney under physiological and pathophysiological conditions is needed. In this review, we provide an overview of the current knowledge of the anatomy of efferent and afferent renal nerves and their functions in normal and pathophysiological conditions. We also suggest further avenues of research for development of novel therapies targeting the renal nerves.
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Affiliation(s)
- John W Osborn
- Department of Surgery, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA;
| | - Roman Tyshynsky
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Lucy Vulchanova
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
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5
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Ahmari N, Hayward LF, Zubcevic J. The importance of bone marrow and the immune system in driving increases in blood pressure and sympathetic nerve activity in hypertension. Exp Physiol 2020; 105:1815-1826. [PMID: 32964557 DOI: 10.1113/ep088247] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/01/2020] [Indexed: 12/27/2022]
Abstract
NEW FINDINGS What is the topic of this review? This manuscript provides a review of the current understanding of the role of the sympathetic nervous system in regulation of bone marrow-derived immune cells and the effect that the infiltrating bone marrow cells may have on perpetuation of the sympathetic over-activation in hypertension. What advances does it highlight? We highlight the recent advances in understanding of the neuroimmune interactions both peripherally and centrally as they relate to blood pressure control. ABSTRACT The sympathetic nervous system (SNS) plays a crucial role in maintaining physiological homeostasis, in part by regulating, integrating and orchestrating processes between many physiological systems, including the immune system. Sympathetic nerves innervate all primary and secondary immune organs, and all cells of the immune system express β-adrenoreceptors. In turn, immune cells can produce cytokines, chemokines and neurotransmitters capable of modulating neuronal activity and, ultimately, SNS activity. Thus, the essential role of the SNS in the regulation of innate and adaptive immune functions is mediated, in part, via β-adrenoreceptor-induced activation of bone marrow cells by noradrenaline. Interestingly, both central and systemic inflammation are well-established hallmarks of hypertension and its co-morbidities, including an inflammatory process involving the transmigration and infiltration of immune cells into tissues. We propose that physiological states that prolong β-adrenoreceptor activation in bone marrow can disrupt neuroimmune homeostasis and impair communication between the immune system and SNS, leading to immune dysregulation, which, in turn, is sustained via a central mechanism involving neuroinflammation.
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Affiliation(s)
- Niousha Ahmari
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Linda F Hayward
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Jasenka Zubcevic
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
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6
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Abstract
Despite availability of effective drugs for hypertension therapy, significant numbers of hypertensive patients fail to achieve recommended blood pressure levels on ≥3 antihypertensive drugs of different classes. These individuals have a high prevalence of adverse cardiovascular events and are defined as having resistant hypertension (RHT) although nonadherence to prescribed antihypertensive medications is common in patients with apparent RHT. Furthermore, apparent and true RHT often display increased sympathetic activity. Based on these findings, technology was developed to treat RHT by suppressing sympathetic activity with electrical stimulation of the carotid baroreflex and catheter-based renal denervation (RDN). Over the last 15 years, experimental and clinical studies have provided better understanding of the physiological mechanisms that account for blood pressure lowering with baroreflex activation and RDN and, in so doing, have provided insight into which patients in this heterogeneous hypertensive population are most likely to respond favorably to these device-based therapies. Experimental studies have also played a role in modifying device technology after early clinical trials failed to meet key endpoints for safety and efficacy. At the same time, these studies have exposed potential differences between baroreflex activation and RDN and common challenges that will likely impact antihypertensive treatment and clinical outcomes in patients with RHT. In this review, we emphasize physiological studies that provide mechanistic insights into blood pressure lowering with baroreflex activation and RDN in the context of progression of clinical studies, which are now at a critical point in determining their fate in RHT management.
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Affiliation(s)
- Thomas E Lohmeier
- From the Department of Physiology and Biophysics (T.E.L., J.E.H.), University of Mississippi Medical Center, Jackson
| | - John E Hall
- From the Department of Physiology and Biophysics (T.E.L., J.E.H.), University of Mississippi Medical Center, Jackson.,Mississippi Center for Obesity Research (J.E.H.), University of Mississippi Medical Center, Jackson
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7
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Yang T, Richards EM, Pepine CJ, Raizada MK. The gut microbiota and the brain-gut-kidney axis in hypertension and chronic kidney disease. Nat Rev Nephrol 2019; 14:442-456. [PMID: 29760448 DOI: 10.1038/s41581-018-0018-2] [Citation(s) in RCA: 410] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Crosstalk between the gut microbiota and the host has attracted considerable attention owing to its involvement in diverse diseases. Chronic kidney disease (CKD) is commonly associated with hypertension and is characterized by immune dysregulation, metabolic disorder and sympathetic activation, which are all linked to gut dysbiosis and altered host-microbiota crosstalk. In this Review, we discuss the complex interplay between the brain, the gut, the microbiota and the kidney in CKD and hypertension and explain our brain-gut-kidney axis hypothesis for the pathogenesis of these diseases. Consideration of the role of the brain-gut-kidney axis in the maintenance of normal homeostasis and of dysregulation of this axis in CKD and hypertension could lead to the identification of novel therapeutic targets. In addition, the discovery of unique microbial communities and their associated metabolites and the elucidation of brain-gut-kidney signalling are likely to fill fundamental knowledge gaps leading to innovative research, clinical trials and treatments for CKD and hypertension.
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Affiliation(s)
- Tao Yang
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Elaine M Richards
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Carl J Pepine
- Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mohan K Raizada
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA.
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8
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Schreier B, Hünerberg M, Mildenberger S, Rabe S, Bethmann D, Wickenhauser C, Gekle M. Deletion of the EGF receptor in vascular smooth muscle cells prevents chronic angiotensin II-induced arterial wall stiffening and media thickening. Acta Physiol (Oxf) 2018; 222. [PMID: 29152859 DOI: 10.1111/apha.12996] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 01/13/2023]
Abstract
AIM In vivo vascular smooth muscle cell (VSMC) EGF receptor (EGFR) contributes to acute angiotensin II (AII) effects on vascular tone and blood pressure. The ubiquitously expressed EGFR has been implicated in vascular remodelling preceding end-organ damage by pharmacological inhibition, and AII signalling in cultured vascular cells is partly EGFR-dependent. However, the role of VSMC-EGFR in vivo during AII-induced pathophysiological processes is not known. METHODS This study assesses the in vivo relevance of VSMC-EGFR during chronic AII challenge without further stressors, using a mouse model with inducible, VSMC-specific EGFR knock out (VSMC-EGFR-KO). In these mice functional and structural vascular, renal and cardiac effects or biomarkers were investigated in vivo and ex vivo. RESULTS Vascular smooth muscle cell-EGFR-KO prevented AII-induced media hypertrophy of mesenteric arteries, renal arterioles and the aorta, VSMC ERK1/2-phosphorylation as well as the impairment of vascular compliance. Furthermore, induction of vascular fibrosis, creatinineamia, renal interstitial fibrosis as well as the increase in fractional water excretion was prevented. AII-induced increase in systolic blood pressure was mitigated. By contrast, endothelial dysfunction, induction of vascular inflammatory marker mRNA and albuminuria were not inhibited. Cardiac and cardiomyocyte hypertrophy were also not prevented by VSMC-EGFR-KO. CONCLUSION Vascular smooth muscle cell-EGFRs are relevant for pathological AII action in vivo. Our data show in vivo and ex vivo the necessity of VSMC-EGFR for AII-induced structural and functional vascular remodelling, not including endothelial dysfunction. Hereby, VSMC-EGFR gains importance for complete AII-induced renal end-organ damage succeeding vascular remodelling.
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Affiliation(s)
- B. Schreier
- Julius-Bernstein-Institute of Physiology; Martin Luther University Halle-Wittenberg; Halle Germany
| | - M. Hünerberg
- Julius-Bernstein-Institute of Physiology; Martin Luther University Halle-Wittenberg; Halle Germany
| | - S. Mildenberger
- Julius-Bernstein-Institute of Physiology; Martin Luther University Halle-Wittenberg; Halle Germany
| | - S. Rabe
- Julius-Bernstein-Institute of Physiology; Martin Luther University Halle-Wittenberg; Halle Germany
| | - D. Bethmann
- Institute of Pathology; Martin Luther University Halle-Wittenberg; Halle Germany
| | - C. Wickenhauser
- Institute of Pathology; Martin Luther University Halle-Wittenberg; Halle Germany
| | - M. Gekle
- Julius-Bernstein-Institute of Physiology; Martin Luther University Halle-Wittenberg; Halle Germany
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9
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Hong MN, Li XD, Chen DR, Ruan CC, Xu JZ, Chen J, Wu YJ, Ma Y, Zhu DL, Gao PJ. Renal denervation attenuates aldosterone expression and associated cardiovascular pathophysiology in angiotensin II-induced hypertension. Oncotarget 2018; 7:67828-67840. [PMID: 27661131 PMCID: PMC5356522 DOI: 10.18632/oncotarget.12182] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/14/2016] [Indexed: 12/20/2022] Open
Abstract
The sympathetic nervous system interacts with the renin-angiotensin-aldosterone system (RAAS) contributing to cardiovascular diseases. In this study, we sought to determine if renal denervation (RDN) inhibits aldosterone expression and associated cardiovascular pathophysiological changes in angiotensin II (Ang II)-induced hypertension. Bilateral RDN or SHAM operation was performed before chronic 14-day Ang II subcutaneous infusion (200ng/kg/min) in male Sprague-Dawley rats. Bilateral RDN blunted Ang II-induced hypertension and ameliorated the mesenteric vascular dysfunction. Cardiovascular hypertrophy in response to Ang II was significantly attenuated by RDN as shown by histopathology and transthoracic echocardiography. Moreover, Ang II-induced vascular and myocardial inflammation and fibrosis were suppressed by RDN with concurrent decrease in fibronectin and collagen deposition, macrophage infiltration, and MCP-1 expression. Interestingly, RDN also inhibited Ang II-induced aldosterone expression in the plasma, kidney and heart. This was associated with the reduction of calcitonin gene-related peptide (CGRP) in the adrenal gland. Ang II promoted aldosterone secretion which was partly attenuated by CGRP in the adrenocortical cell line, suggesting a protective role of CGRP in this model. Activation of transforming growth factor-β (TGF-β)/Smad and mitogen-activated protein kinases (MAPKs) signaling pathway was both inhibited by RDN especially in the heart. These results suggest that the regulation of the renal sympathetic nerve in Ang II-induced hypertension and associated cardiovascular pathophysiological changes is likely mediated by aldosterone, with CGRP involvement.
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Affiliation(s)
- Mo-Na Hong
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Xiao-Dong Li
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China.,Laboratory of Vascular Biology and Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dong-Rui Chen
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Cheng-Chao Ruan
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China.,Laboratory of Vascular Biology and Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian-Zhong Xu
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Jing Chen
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Yong-Jie Wu
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Yu Ma
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Ding-Liang Zhu
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China
| | - Ping-Jin Gao
- Department of Hypertension, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Hypertension, Shanghai, China.,Laboratory of Vascular Biology and Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai, China
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10
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Holbein WW, Blackburn MB, Andrade MA, Toney GM. Burst patterning of hypothalamic paraventricular nucleus-driven sympathetic nerve activity in ANG II-salt hypertension. Am J Physiol Heart Circ Physiol 2017; 314:H530-H541. [PMID: 29167122 DOI: 10.1152/ajpheart.00560.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
ANG II-salt hypertension selectively increases splanchnic sympathetic nerve activity (sSNA), but the extent to which this reflects increased respiratory versus cardiac rhythmic bursting is unknown. Here, integrated sSNA was elevated in ANG II-infused rats fed a high-salt (2% NaCl) diet (ANG II-HSD) compared with vehicle-infused rats fed a normal-salt (0.4% NaCl) diet (Veh-NSD; P < 0.01). Increased sSNA was not accompanied by increased inspiratory or expiratory bursting, consistent with no group difference in central inspiratory drive. Consistent with preserved inhibitory baroreflex entrainment of elevated sSNA in ANG II-HSD rats, the time integral ( P < 0.05) and amplitude ( P < 0.01) of cardiac rhythmic sSNA were increased. Consistent with activity of hypothalamic paraventricular nucleus (PVN) neurons supporting basal SNA in ANG II-salt hypertension, inhibition of PVN with the GABA-A receptor agonist muscimol reduced mean arterial pressure (MAP) and integrated sSNA only in the ANG II-HSD group ( P < 0.001). PVN inhibition had no effect on respiratory rhythmic sSNA bursting in either group but reduced cardiac rhythmic sSNA in ANG II-HSD rats only ( P < 0.01). The latter likely reflected reduced inhibitory baroreflex entrainment subsequent to the fall of MAP. Of note is that MAP as well as integrated and rhythmic burst patterns of sSNA were similar in vehicle-infused rats whether they were fed a normal or high-salt diet. Findings indicate that PVN neurons support elevated sSNA in ANG II-HSD rats by driving a tonic component of activity without altering respiratory or cardiac rhythmic bursting. Because sSNA was unchanged in Veh-HSD rats, activation of PVN-driven tonic sSNA appears to require central actions of ANG II. NEW & NOTEWORTHY ANG II-salt hypertension is strongly neurogenic and depends on hypothalamic paraventricular nucleus (PVN)-driven splanchnic sympathetic nerve activity (sSNA). Here, respiratory and cardiac bursts of sSNA were preserved in ANG II-salt rats and unaltered by PVN inhibition, suggesting that PVN neurons drive a tonic component of sSNA rather than modulating dominant patterns of burst discharge.
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Affiliation(s)
- Walter W Holbein
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Megan B Blackburn
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Mary Ann Andrade
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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11
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Schiller AM, Pellegrino PR, Zucker IH. Eppur Si Muove: The dynamic nature of physiological control of renal blood flow by the renal sympathetic nerves. Auton Neurosci 2017; 204:17-24. [PMID: 27514571 PMCID: PMC5290256 DOI: 10.1016/j.autneu.2016.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/11/2016] [Accepted: 08/01/2016] [Indexed: 02/06/2023]
Abstract
Tubuloglomerular feedback and the myogenic response are widely appreciated as important regulators of renal blood flow, but the role of the sympathetic nervous system in physiological renal blood flow control remains controversial. Where classic studies using static measures of renal blood flow failed, dynamic approaches have succeeded in demonstrating sympathetic control of renal blood flow under normal physiological conditions. This review focuses on transfer function analysis of renal pressure-flow, which leverages the physical relationship between blood pressure and flow to assess the underlying vascular control mechanisms. Studies using this approach indicate that the renal nerves are important in the rapid regulation of the renal vasculature. Animals with intact renal innervation show a sympathetic signature in the frequency range associated with sympathetic vasomotion that is eliminated by renal denervation. In conscious rabbits, this sympathetic signature exerts vasoconstrictive, baroreflex control of renal vascular conductance, matching well with the rhythmic, baroreflex-influenced control of renal sympathetic nerve activity and complementing findings from other studies employing dynamic approaches to study renal sympathetic vascular control. In this light, classic studies reporting that nerve stimulation and renal denervation do not affect static measures of renal blood flow provide evidence for the strength of renal autoregulation rather than evidence against physiological renal sympathetic control of renal blood flow. Thus, alongside tubuloglomerular feedback and the myogenic response, renal sympathetic outflow should be considered an important physiological regulator of renal blood flow. Clinically, renal sympathetic vasomotion may be important for solving the problems facing the field of therapeutic renal denervation.
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Affiliation(s)
- Alicia M Schiller
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States; US Army Institute of Surgical Research, JBSA Fort Sam Houston, TX, United States
| | - Peter Ricci Pellegrino
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States.
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Abstract
The objective of this review is to provide an in-depth evaluation of how renal nerves regulate renal and cardiovascular function with a focus on long-term control of arterial pressure. We begin by reviewing the anatomy of renal nerves and then briefly discuss how the activity of renal nerves affects renal function. Current methods for measurement and quantification of efferent renal-nerve activity (ERNA) in animals and humans are discussed. Acute regulation of ERNA by classical neural reflexes as well and hormonal inputs to the brain is reviewed. The role of renal nerves in long-term control of arterial pressure in normotensive and hypertensive animals (and humans) is then reviewed with a focus on studies utilizing continuous long-term monitoring of arterial pressure. This includes a review of the effect of renal-nerve ablation on long-term control of arterial pressure in experimental animals as well as humans with drug-resistant hypertension. The extent to which changes in arterial pressure are due to ablation of renal afferent or efferent nerves are reviewed. We conclude by discussing the importance of renal nerves, relative to sympathetic activity to other vascular beds, in long-term control of arterial pressure and hypertension and propose directions for future research in this field. © 2017 American Physiological Society. Compr Physiol 7:263-320, 2017.
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Affiliation(s)
- John W Osborn
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jason D Foss
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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Shimoura CG, Lincevicius GS, Nishi EE, Girardi ACC, Simon KA, Bergamaschi CT, Campos RR. Increased Dietary Salt Changes Baroreceptor Sensitivity and Intrarenal Renin-Angiotensin System in Goldblatt Hypertension. Am J Hypertens 2017; 30:28-36. [PMID: 27629265 DOI: 10.1093/ajh/hpw107] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 08/18/2016] [Accepted: 08/19/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Renovascular hypertension (2-kidney 1-clip model (2K1C)) is characterized by renin-angiotensin system (RAS) activation. Increased Angiotensin II (AngII) leads to sympathoexcitation, oxidative stress, and alterations in sodium and water balance. AIM The aim of this study was to evaluate whether a discrete increase in sodium chloride intake in 2K1C rats leads to changes in cardiovascular and autonomic function, oxidative stress, and renin angiotensin aldosterone system. METHODS After 4 weeks of induction of hypertension, rats were fed a normal sodium diet (0.4% NaCl) or a high-sodium diet (2% NaCl) for 2 consecutive weeks. Experiments were carried out for 6 weeks after clipping. Mean arterial pressure (MAP), renal sympathetic nerve activity (rSNA), arterial baroreflex control of rSNA, and heart rate (HR) were assessed. Thiobarbituric acid reactive substances and glutathione were measured as indicators of systemic oxidative stress. Angiostensin-converting enzyme (ACE), ACE2, and angiotensinogen were evaluated in clipped and unclipped kidneys as also urinary angiotensinogen and plasma renin activity. Angiotensinogen, plasma renin activity (PRA) and angiotensin-converting enzyme (ACE) and ACE2 in clipped and unclipped kidneys were evaluated. RESULTS High-sodium diet did not change systemic oxidative stress, and basal values of MAP, HR, or rSNA; however, increased renal (-0.7±0.2 vs. -1.5±0.1 spikes/s/mm Hg) and cardiac (-0.9±0.14 vs. -1.5±0.14 bpm/mm Hg) baroreceptor reflex sensitivity in 2K1C rats. Although there was no alteration in PRA, a high-salt diet significantly decreased urinary angiotensinogen, ACE, and ACE2 expressions in the clipped and unclipped kidneys. CONCLUSIONS Increased arterial baroreceptor control associated with a suppression of the intrarenal RAS in the 2K1C rats on high-salt diet provide a salt-resistant effect on hypertension and sympathoexcitation in renovascular hypertensive rats.
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Affiliation(s)
- Caroline G Shimoura
- Cardiovascular Division-Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Gisele S Lincevicius
- Cardiovascular Division-Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Erika E Nishi
- Cardiovascular Division-Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Adriana C C Girardi
- Heart Institute (InCor) University of São Paulo Medical School, São Paulo, São Paulo, Brazil
| | - Karin A Simon
- Department of Biological Sciences, Universidade Federal de São Paulo, Diadema, Brazil
| | - Cassia T Bergamaschi
- Cardiovascular Division-Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ruy R Campos
- Cardiovascular Division-Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil;
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Abstract
Resistant hypertension defined as requiring 3 or more complementary antihypertensive drugs at maximally tolerated doses accounts for approximately 3% to 4% of all cases of hypertension. Its increased incidence over the past decade is related to the increase in obesity in the Western world. There are a number of dietary factors that affect sympathetic tone including sodium intake apart from increased body mass. This article discusses the mechanisms of sympathetic stimulation and activation in the context of animal models and human studies. In addition, there is a review of clinical trials with and without device therapy that summarizes the clinical findings. Effective management should be based on pathophysiologic principles and a focus on blood pressure reduction to levels well below 150/90 mm Hg because outcome trial evidence and Food and Drug Administration guidance supports this construct. The key to success of device-based therapy depends on identifying the cohort with true resistant hypertension that can benefit from therapies that are adjuncts to pharmacotherapy. Physicians need to concentrate on educating the patient on lifestyle modifications and themselves on use of proper combinations of antihypertensive medications. If this approach fails to result in a safe level of blood pressure then the patient should be referred to a board-certified clinical hypertension specialist.
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Combined Aliskiren and L-arginine treatment reverses renovascular hypertension in an animal model. Hypertens Res 2015; 38:471-7. [PMID: 25740291 DOI: 10.1038/hr.2015.16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 01/12/2015] [Accepted: 01/25/2015] [Indexed: 11/08/2022]
Abstract
Renovascular hypertension is characterized by increased renal sympathetic activity, angiotensin II and by endothelial dysfunction. The purpose of this study was to determine the role of renal sympathetic nerve activity (RSNA) in mediating the anti-hypertensive effects of aliskiren (ALSK) and L-arginine (L-ARG) in a rat renovascular hypertension model. Hypertension was induced by clipping the right renal artery, and the following five groups were divided: SHAM operated; 2-kidney, 1-clip (2K1C); 2K1C plus ALSK; 2K1C plus L-ARG; and 2K1C plus ALSK+ L-ARG. The systolic blood pressure (SBP) of 2K1C rats increased from 114.4±5.2 to 204±12.7 mm Hg (P<0.05) and was only reduced by ALSK+L-ARG treatment (138.4±4.37 mm Hg). The 2K1C hypertension increased the baseline RSNA (SHAM: 62.4±6.39 vs. 2K1C: 97.4±8.43%). L-ARG or ALSK+L-ARG treatment significantly decreased baseline RSNA (2K1C L-ARG:70.7±2.39; 2K1C ALSK+L-ARG: 69.3±4.23%), but ALSK treatment alone did not (2K1C ALSK: 84.2±2.5%). Urinary water, Na(+), Cl(-) and urea excretion were similar in the 2K1C L-ARG, 2K1C ALSK+L-ARG and SHAM groups. The combination of ALSK+L-ARG restored urine flow and increased the glomerular filtration rate. The nNOS expression in the non clipped kidney was significantly increased in 2K1C ALSK+L-ARG rats. In conclusion, combined ALSK+L-ARG treatment normalizes SBP and prevents renal dysfunction in 2K1C hypertensive rats.
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Kuroki MT, Fink GD, Osborn JW. Comparison of arterial pressure and plasma ANG II responses to three methods of subcutaneous ANG II administration. Am J Physiol Heart Circ Physiol 2014; 307:H670-9. [PMID: 24993045 DOI: 10.1152/ajpheart.00922.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Angiotensin II (ANG II)-induced hypertension is a commonly studied model of experimental hypertension, particularly in rodents, and is often generated by subcutaneous delivery of ANG II using Alzet osmotic minipumps chronically implanted under the skin. We have observed that, in a subset of animals subjected to this protocol, mean arterial pressure (MAP) begins to decline gradually starting the second week of ANG II infusion, resulting in a blunting of the slow pressor response and reduced final MAP. We hypothesized that this variability in the slow pressor response to ANG II was mainly due to factors unique to Alzet pumps. To test this, we compared the pressure profile and changes in plasma ANG II levels during subcutaneous ANG II administration (150 ng·kg(-1)·min(-1)) using either Alzet minipumps, iPrecio implantable pumps, or a Harvard external infusion pump. At the end of 14 days of ANG II, MAP was highest in the iPrecio group (156 ± 3 mmHg) followed by Harvard (140 ± 3 mmHg) and Alzet (122 ± 3 mmHg) groups. The rate of the slow pressor response, measured as daily increases in pressure averaged over days 2-14 of ANG II, was similar between iPrecio and Harvard groups (2.7 ± 0.4 and 2.2 ± 0.4 mmHg/day) but was significantly blunted in the Alzet group (0.4 ± 0.4 mmHg/day) due to a gradual decline in MAP in a subset of rats. We also found differences in the temporal profile of plasma ANG II between infusion groups. We conclude that the gradual decline in MAP observed in a subset of rats during ANG II infusion using Alzet pumps is mainly due to pump-dependent factors when applied in this particular context.
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Affiliation(s)
- Marcos T Kuroki
- Graduate Program in Neuroscience and Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota; and
| | - Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - John W Osborn
- Graduate Program in Neuroscience and Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota; and
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17
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Isaksson GL, Stubbe J, Lyngs Hansen P, Jensen BL, Bie P. Salt sensitivity of renin secretion, glomerular filtration rate and blood pressure in conscious Sprague-Dawley rats. Acta Physiol (Oxf) 2014; 210:446-54. [PMID: 24188244 DOI: 10.1111/apha.12191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 10/15/2013] [Accepted: 10/30/2013] [Indexed: 12/20/2022]
Abstract
AIM We hypothesized that in normal rats in metabolic steady state, (i) the plasma renin concentration (PRC) is log-linearly related to Na(+) intake (NaI), (ii) the concurrent changes in mean arterial pressure (MABP) and glomerular filtration rate (GFR) are negligible and (iii) the function PRC = f(NaI) is altered by β₁-adrenoceptor blockade (metoprolol) and surgical renal denervation (DNX). METHODS In catheterized, conscious rats on low-Na(+) diet (0.004% Na(+)), NaI was increased by up to 120-fold, in four 3-day steps, by intravenous saline infusion. MABP was recorded continuously, PRC measured in arterial blood, and GFR estimated by inulin clearance. RESULTS Steady states were achieved within 3 days. PRC [mIU L(-1)] was log-linearly related to NaI [mmol kg(-1) day(-1)]: PRC = -9.9 log (NaI) + 22. Set point (22 mIU L(-1) at NaI = 1) and slope (9.9 mIU per decade NaI) were independent of metoprolol administration and DNX. MABP and GFR were markedly salt-sensitive: MABP [mmHg] = 4.9 log (NaI) + 99 (P < 0.01), and GFR [mL min(-1)] = 1.4 log (NaI) + 8.3 (P < 0.01). MABP increased similarly (approx. 10%, P < 0.001) irrespective of pre-treatment. Metoprolol, but not DNX, reduced MABP, HR, and GFR (all P < 0.01). Salt sensitivity of GFR was not observed in DNX rats. CONCLUSION Log-linear relations to sodium intake exist not only for PRC, but also for MABP and GFR, which per 10-fold increase in sodium intake rose by 5 mmHg and 1.4 mL min(-1) respectively. Steady-state levels of PRC appear independent of renal nerves. MABP and GFR seem markedly salt sensitive in normal rats.
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Affiliation(s)
- G. L. Isaksson
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - J. Stubbe
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - P. Lyngs Hansen
- Department of Physics, Chemistry and Pharmacy; University of Southern Denmark; Odense Denmark
| | - B. L. Jensen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - P. Bie
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
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18
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Guild SJ, McBryde FD, Malpas SC, Barrett CJ. High Dietary Salt and Angiotensin II Chronically Increase Renal Sympathetic Nerve Activity. Hypertension 2012; 59:614-20. [DOI: 10.1161/hypertensionaha.111.180885] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Sarah-Jane Guild
- From the Circulatory Control Laboratory, Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Fiona D. McBryde
- From the Circulatory Control Laboratory, Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Simon C. Malpas
- From the Circulatory Control Laboratory, Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Carolyn J. Barrett
- From the Circulatory Control Laboratory, Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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Abstract
Hypertension is one of the leading causes of disability or death due to stroke, heart attack and kidney failure. Because the etiology of essential hypertension is not known and may be multifactorial, the use of experimental animal models has provided valuable information regarding many aspects of the disease, which include etiology, pathophysiology, complications and treatment. The models of hypertension are various, and in this review, we provide a brief overview of the most widely used animal models, their features and their importance.
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Affiliation(s)
- Waleska C Dornas
- Research in Biological Sciences-NUPEB, School of Nutrition, Ouro Preto University, Minas Gerais, Brazil
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21
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Kuroki MT, Guzman PA, Fink GD, Osborn JW. Time-dependent changes in autonomic control of splanchnic vascular resistance and heart rate in ANG II-salt hypertension. Am J Physiol Heart Circ Physiol 2011; 302:H763-9. [PMID: 22114134 DOI: 10.1152/ajpheart.00930.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies suggest that ANG II-induced hypertension in rats fed a high-salt (HS) diet (ANG II-salt hypertension) has a neurogenic component dependent on an enhanced sympathetic tone to the splanchnic veins and independent from changes in sympathetic nerve activity to the kidney or hind limb. The purpose of this study was to extend these findings and test whether altered autonomic control of splanchnic resistance arteries and the heart also contributes to the neurogenic component. Mean arterial pressure (MAP), heart rate (HR), superior mesenteric artery blood flow, and mesenteric vascular resistance (MVR) were measured during 4 control days, 14 days of ANG II delivered subcutaneously (150 ng·kg(-1)·min(-1)), and 4 days of recovery in conscious rats fed a HS (2% NaCl) or low-salt (LS; 0.1% NaCl) diet. Autonomic effects on MAP, HR, and MVR were assessed by acute ganglionic blockade with hexamethonium (20 mg/kg iv) on day 3 of control, days 1, 3, 5, 7, 10, and 13 of ANG II, and day 4 of recovery. MVR increased during ANG II infusion in HS and LS rats but remained elevated only in HS rats. Additionally, the MVR response to hexamethonium was enhanced on days 10 and 13 of ANG II selectively in HS rats. Compared with LS rats, HR in HS rats was higher during the 2nd wk of ANG II, and its response to hexamethonium was greater on days 7, 10, and 13 of ANG II. These results suggest that ANG II-salt hypertension is associated with delayed changes in autonomic control of splanchnic resistance arteries and the heart.
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Affiliation(s)
- Marcos T Kuroki
- Dept. of Integrative Biology and Physiology, 321 Church St. SE, Rm. 6-125 Jackson Hall, Minneapolis, MN 55455, USA
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Chen AD, Zhang SJ, Yuan N, Xu Y, De W, Gao XY, Zhu GQ. Angiotensin AT1receptors in paraventricular nucleus contribute to sympathetic activation and enhanced cardiac sympathetic afferent reflex in renovascular hypertensive rats. Exp Physiol 2011; 96:94-103. [DOI: 10.1113/expphysiol.2010.054353] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Malpas SC. Sympathetic nervous system overactivity and its role in the development of cardiovascular disease. Physiol Rev 2010; 90:513-57. [PMID: 20393193 DOI: 10.1152/physrev.00007.2009] [Citation(s) in RCA: 431] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
This review examines how the sympathetic nervous system plays a major role in the regulation of cardiovascular function over multiple time scales. This is achieved through differential regulation of sympathetic outflow to a variety of organs. This differential control is a product of the topographical organization of the central nervous system and a myriad of afferent inputs. Together this organization produces sympathetic responses tailored to match stimuli. The long-term control of sympathetic nerve activity (SNA) is an area of considerable interest and involves a variety of mediators acting in a quite distinct fashion. These mediators include arterial baroreflexes, angiotensin II, blood volume and osmolarity, and a host of humoral factors. A key feature of many cardiovascular diseases is increased SNA. However, rather than there being a generalized increase in SNA, it is organ specific, in particular to the heart and kidneys. These increases in regional SNA are associated with increased mortality. Understanding the regulation of organ-specific SNA is likely to offer new targets for drug therapy. There is a need for the research community to develop better animal models and technologies that reflect the disease progression seen in humans. A particular focus is required on models in which SNA is chronically elevated.
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Affiliation(s)
- Simon C Malpas
- Department of Physiology and the Auckland Bioengineering Institute, University of Auckland and Telemetry Research Ltd., Auckland, New Zealand.
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24
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Castrop H, Höcherl K, Kurtz A, Schweda F, Todorov V, Wagner C. Physiology of Kidney Renin. Physiol Rev 2010; 90:607-73. [PMID: 20393195 DOI: 10.1152/physrev.00011.2009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Klaus Höcherl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Vladimir Todorov
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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Evans RG, Head GA, Eppel GA, Burke SL, Rajapakse NW. Angiotensin II and neurohumoral control of the renal medullary circulation. Clin Exp Pharmacol Physiol 2010; 37:e58-69. [DOI: 10.1111/j.1440-1681.2009.05233.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Enhanced responses to ganglion blockade do not reflect sympathetic nervous system contribution to angiotensin II-induced hypertension. J Hypertens 2009; 27:1838-48. [PMID: 19512943 DOI: 10.1097/hjh.0b013e32832dd0d8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We examined whether a specific increase in sympathetic nervous system (SNS) activity accounts for the enhanced depressor response to ganglion blockade in angiotensin II (AngII)-induced hypertension in rabbits or whether it reflects a general increased sensitivity of arterial pressure to vasodilatation. METHODS Rabbits were renal denervated or sham-operated and 2 weeks later AngII (50 ng/kg per min) infusion commenced. Mean arterial pressure (MAP) responses to ganglion blockade (pentolinium) and vasodilators nitroprusside and adenosine were measured 2-4 weeks later. RESULTS Basal MAP was 74 +/- 2 mmHg and maximum hypotensive responses to pentolinium, nitroprusside and adenosine were -17 +/- 2, -17 +/- 1 and -21 +/- 2 mmHg. AngII increased MAP similarly in intact and renal denervated rabbits (+25 +/- 4 mmHg and +31 +/- 4 mmHg, respectively). In intact rabbits, depressor responses to pentolinium were augmented by 75% during AngII infusion but responses to vasodilators also increased by 73-106% suggesting general augmentation of vascular reactivity rather than a specific increase in SNS neural activity. Consistent with this notion, total noradrenaline spillover was similar in normal and AngII-treated rabbits. In renal denervated rabbits, AngII enhanced depressor responses to vasodilators but not pentolinium, suggesting that sympathetic activity may be reduced by AngII hypertension when renal nerves are absent. In anaesthetized rabbits, methoxamine-induced decreases in hindlimb vascular conductance were greater in hypertensive than normotensive rabbits suggesting the presence of vascular hypertrophy of sufficient magnitude to explain increased responses to ganglion blockade and vasodilators. CONCLUSION Enhanced depressor responses to ganglion blockade in AngII hypertension do not reflect augmented SNS activity, but rather, augmented sympathetic vasoconstriction mediated by a vascular amplifier effect.
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McBryde FD, Malpas SC, Guild SJ, Barrett CJ. A high-salt diet does not influence renal sympathetic nerve activity: a direct telemetric investigation. Am J Physiol Regul Integr Comp Physiol 2009; 297:R396-402. [DOI: 10.1152/ajpregu.90741.2008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The importance of dietary salt in the development of hypertension has long been a source of controversy. Recent studies suggest a combination of high-salt and ANG II infusion may increase sympathetic drive; however, the effect of a change in dietary salt alone is unclear. Using telemetry, we recorded renal sympathetic nerve activity (RSNA), arterial pressure (MAP), and heart rate (HR) in seven New Zealand white rabbits before and during a 6-day period of increased salt intake (normal NaCl 0.5 g·kg−1·day−1, high NaCl 2.5 g·kg−1·day−1) and a second group of seven rabbits with normal salt intake throughout. The responses to stressful stimuli encountered in the laboratory were recorded and compared with rest in control and high-salt groups. Resting MAP, HR, and RSNA were not significantly altered with high salt intake [88 ± 5 vs. 91 ± 6 mmHg; 251 ± 8 vs. 244 ± 9 beats per minute (bpm); 9.7 ± and 1.2 vs. 10.8 ± 1.7 normalized units (nu)] despite significant reductions in plasma renin activity (1.88 ± 0.18 vs. 1.27 ± 0.15 nmol ANG I·l−1·h−1; P < 0.05) and ANG II (7.5 ± 1.2 vs. 4.3 ± 0.8 pmol/l). Increasing levels of stressful stimuli (resting in home cage, containment in box, handling, and nasopharyngeal activation) in animals on a normal salt diet caused graded increases in MAP (89 ± 2 mmHg, 95 ± 2 mmHg, 107 ± 4 mmHg, and 122 ± 5 mmHg, respectively) and RSNA (9.7 ± 0.9 nu; 11.8 ± 2.7 nu; 31.4 ± 3.7 nu; 100 nu) but not HR (245 ± 8 bpm; 234 ± 8 bpm; 262 ± 9 bpm; 36 ± 5 bpm). High dietary salt did not significantly alter the responses to stress. We conclude that a 6-day period of high salt intake does not alter the level of RSNA, with non-neural mechanisms primarily responsible for the observed renin-angiotensin system suppression.
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Burke SL, Evans RG, Moretti JL, Head GA. Levels of Renal and Extrarenal Sympathetic Drive in Angiotensin II–Induced Hypertension. Hypertension 2008; 51:878-83. [DOI: 10.1161/hypertensionaha.107.100800] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We examined the contribution of the renal nerves to mean arterial pressure (MAP) during 5-week chronic infusion of angiotensin II (Ang II; 50 ng/kg per minute SC) in conscious rabbits. Basal MAP was 68±1 mm Hg, and the maximum depressor response to ganglion blockade was −20±2 mm Hg. MAP increased by 25±2 mm Hg after 1 week and remained stable over the next 4 weeks. Depressor responses to pentolinium (6 mg/kg IV) were similar to control during the first week of hypertension but thereafter became increasingly greater in Ang II–treated rabbits but not vehicle-treated rabbits. After 5 weeks, the fall in MAP was 54% greater in Ang II- than in vehicle-treated rabbits (−34±2 versus −22±2 mm Hg), but renal sympathetic nerve activity was similar in both groups. Renal denervation produced a small fall in MAP in all of the vehicle-treated rabbits after 4 days (−6±2 mm Hg;
P
=0.01), but there was no consistent effect in hypertensive rabbits. The depressor response to ganglion blockade was enhanced in vehicle-treated but not Ang II–treated rabbits. The finding that renal sympathetic nerve activity is not altered by Ang II hypertension nor is the hypertension altered by renal denervation suggests that renal sympathetic nerves do not contribute to the hypertension. The greater depressor effect of acute ganglion blockade in hypertensive rabbits suggests that the sympathetic nervous system exerts increased vasoconstriction in the peripheral vasculature in Ang II–induced hypertension.
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Affiliation(s)
- Sandra L. Burke
- From the Neuropharmacology Laboratory (S.L.B., J.-L.M., G.A.H.), Baker Heart Research Institute, Melbourne, Australia; and the Department of Physiology (R.G.E.), Monash University, Victoria, Australia
| | - Roger G. Evans
- From the Neuropharmacology Laboratory (S.L.B., J.-L.M., G.A.H.), Baker Heart Research Institute, Melbourne, Australia; and the Department of Physiology (R.G.E.), Monash University, Victoria, Australia
| | - John-Luis Moretti
- From the Neuropharmacology Laboratory (S.L.B., J.-L.M., G.A.H.), Baker Heart Research Institute, Melbourne, Australia; and the Department of Physiology (R.G.E.), Monash University, Victoria, Australia
| | - Geoffrey A. Head
- From the Neuropharmacology Laboratory (S.L.B., J.-L.M., G.A.H.), Baker Heart Research Institute, Melbourne, Australia; and the Department of Physiology (R.G.E.), Monash University, Victoria, Australia
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King AJ, Novotny M, Swain GM, Fink GD. Whole body norepinephrine kinetics in ANG II-salt hypertension in the rat. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1262-7. [PMID: 18256139 DOI: 10.1152/ajpregu.00819.2007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The purpose of this study was to investigate total body norepinephrine (NE) kinetics as an index of global sympathetic nervous system (SNS) outflow in a rat model of chronic ANG II-salt hypertension. Male Sprague-Dawley rats fed a 0.4% (normal salt, NS) or 2% (HS) NaCl diet were instrumented with arterial and venous catheters. After 5 days of recovery and a 3-day control period, ANG II (150 ng.kg(-1).min(-1)) was given subcutaneously by minipump for 14 days. Plasma NE levels and total body NE spillover and clearance were determined on control day 3 and ANG II infusion days 7 and 14 using radioisotope dilution principles. To perform this analysis, 3H-NE and NE were measured in arterial plasma after a 90-min infusion of tracer amounts of 3H-NE. Mean arterial pressure (MAP) was similar during the control period in NS and HS rats; however, MAP increased to a higher level in HS rats. During the control period, plasma NE tended to be lower in rats on HS, whereas NE clearance tended to be higher in HS rats. As a result NE spillover was similar in NS and HS rats during the control period. In NS rats, plasma NE, NE spillover, and NE clearance were unchanged by ANG II. In contrast, in rats on the HS diet, plasma NE and NE spillover increased during ANG II infusion, whereas NE clearance was unchanged. In conclusion, a HS diet alone or ANG II infusion in animals fed NS do not affect global sympathetic outflow. However, the additional hypertensive response to ANG II in animals fed HS is accompanied by SNS activation.
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Affiliation(s)
- Andrew J King
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
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