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Chen H, Peng J, Wang T, Wen J, Chen S, Huang Y, Zhang Y. Counter-regulatory renin-angiotensin system in hypertension: Review and update in the era of COVID-19 pandemic. Biochem Pharmacol 2023; 208:115370. [PMID: 36481346 PMCID: PMC9721294 DOI: 10.1016/j.bcp.2022.115370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Cardiovascular disease is the major cause of mortality and disability, with hypertension being the most prevalent risk factor. Excessive activation of the renin-angiotensin system (RAS) under pathological conditions, leading to vascular remodeling and inflammation, is closely related to cardiovascular dysfunction. The counter-regulatory axis of the RAS consists of angiotensin-converting enzyme 2 (ACE2), angiotensin (1-7), angiotensin (1-9), alamandine, proto-oncogene Mas receptor, angiotensin II type-2 receptor and Mas-related G protein-coupled receptor member D. Each of these components has been shown to counteract the effects of the overactivated RAS. In this review, we summarize the latest insights into the complexity and interplay of the counter-regulatory RAS axis in hypertension, highlight the pathophysiological functions of ACE2, a multifunctional molecule linking hypertension and COVID-19, and discuss the function and therapeutic potential of targeting this counter-regulatory RAS axis to prevent and treat hypertension in the context of the current COVID-19 pandemic.
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Affiliation(s)
- Hongyin Chen
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen 518000, Guangdong, China
| | - Jiangyun Peng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong, China,Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan 528200, Guangdong, China
| | - Tengyao Wang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong, China,Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan 528200, Guangdong, China
| | - Jielu Wen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong, China,Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan 528200, Guangdong, China
| | - Sifan Chen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong, China,Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan 528200, Guangdong, China
| | - Yu Huang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China,Corresponding authors
| | - Yang Zhang
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen 518000, Guangdong, China,Corresponding authors
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Kangussu LM, Melo-Braga MN, de Souza Lima BS, Santos RAS, de Andrade HM, Campagnole-Santos MJ. Angiotensin-(1-7) Central Mechanisms After ICV Infusion in Hypertensive Transgenic (mRen2)27 Rats. Front Neurosci 2021; 15:624249. [PMID: 33967677 PMCID: PMC8102993 DOI: 10.3389/fnins.2021.624249] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/30/2021] [Indexed: 11/14/2022] Open
Abstract
Previous data showed hypertensive rats subjected to chronic intracerebroventricular (ICV) infusion of angiotensin-(1-7) presented attenuation of arterial hypertension, improvement of baroreflex sensitivity, restoration of cardiac autonomic balance and a shift of cardiac renin-angiotensin system (RAS) balance toward Ang-(1-7)/Mas receptor. In the present study, we investigated putative central mechanisms related to the antihypertensive effect induced by ICV Ang-(1-7), including inflammatory mediators and the expression/activity of the RAS components in hypertensive rats. Furthermore, we performed a proteomic analysis to evaluate differentially regulated proteins in the hypothalamus of these animals. For this, Sprague Dawley (SD) and transgenic (mRen2)27 hypertensive rats (TG) were subjected to 14 days of ICV infusion with Ang-(1-7) (200 ng/h) or 0.9% sterile saline (0.5 μl/h) through osmotic mini-pumps. We observed that Ang-(1-7) treatment modulated inflammatory cytokines by decreasing TNF-α levels while increasing the anti-inflammatory IL-10. Moreover, we showed a reduction in ACE activity and gene expression of AT1 receptor and iNOS. Finally, our proteomic evaluation suggested an anti-inflammatory mechanism of Ang-(1-7) toward the ROS modulators Uchl1 and Prdx1.
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Affiliation(s)
- Lucas M Kangussu
- National Institute of Science and Technology in Nanobiopharmaceutics (INCT-Nanobiofar), Federal University of Minas Gerais, Belo Horizonte, Brazil.,Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Marcella Nunes Melo-Braga
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Robson A S Santos
- National Institute of Science and Technology in Nanobiopharmaceutics (INCT-Nanobiofar), Federal University of Minas Gerais, Belo Horizonte, Brazil.,Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Maria José Campagnole-Santos
- National Institute of Science and Technology in Nanobiopharmaceutics (INCT-Nanobiofar), Federal University of Minas Gerais, Belo Horizonte, Brazil.,Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
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3
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Andrade-Franzé GMF, Pereira ED, Yosten GLC, Samson WK, Menani JV, De Luca LA, Andrade CAF. Blockade of ERK1/2 activation with U0126 or PEP7 reduces sodium appetite and angiotensin II-induced pressor responses in spontaneously hypertensive rats. Peptides 2021; 136:170439. [PMID: 33166587 DOI: 10.1016/j.peptides.2020.170439] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 01/06/2023]
Abstract
Spontaneously hypertensive rats (SHRs) have increased daily or induced sodium intake compared to normotensive rats. In normotensive rats, angiotensin II (ANG II)-induced sodium intake is blocked by the inactivation of p42/44 mitogen-activated protein kinase, also known as extracellular signal-regulated protein kinase1/2 (ERK1/2). Here we investigated if inhibition of ERK1/2 pathway centrally would change sodium appetite and intracerebroventricular (icv) ANG II-induced pressor response in SHRs. SHRs (280-330 g, n = 07-14/group) with stainless steel cannulas implanted in the lateral ventricle (LV) were used. Water and 0.3 M NaCl intake was induced by the treatment with the diuretic furosemide + captopril (angiotensin converting enzyme blocker) subcutaneously or 24 h of water deprivation (WD) followed by 2 h of partial rehydration with only water (PR). The blockade of ERK1/2 activation with icv injections of U0126 (MEK1/2 inhibitor, 2 mM; 2 μl) reduced 0.3 M NaCl intake induced by furosemide + captopril (5.0 ± 1.0, vs. vehicle: 7.3 ± 0.7 mL/120 min) or WD-PR (4.6 ± 1.3, vs. vehicle: 10.3 ± 1.4 mL/120 min). PEP7 (selective inhibitor of AT1 receptor-mediated ERK1/2 activation, 2 nmol/2 μL) icv also reduced WD-PR-induced 0.3 M NaCl (2.8 ± 0.7, vs. vehicle: 6.8 ± 1.4 mL/120 min). WD-PR-induced water intake was also reduced by U0126 or PEP7. In addition, U0126 or PEP7 icv reduced the pressor response to icv ANG II. Therefore, the present results suggest that central AT1 receptor-mediated ERK1/2 activation is part of the mechanisms involved in sodium appetite and ANG II-induced pressor response in SHRs.
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Affiliation(s)
- G M F Andrade-Franzé
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - E D Pereira
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - G L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - W K Samson
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - L A De Luca
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil.
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4
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Katsi V, Maragkoudakis S, Marketou M, Tsioufis C, Parthenakis F, Tousoulis D. The Role of Angiotensin-(1-7)/Mas Axis and Angiotensin Type 2 Receptors in the Central Nervous System in Cardiovascular Disease and Therapeutics: A Riddle to be Solved. Curr Vasc Pharmacol 2020; 17:319-325. [PMID: 30398116 DOI: 10.2174/1570161117666181105154843] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 09/27/2018] [Accepted: 10/31/2018] [Indexed: 12/18/2022]
Abstract
In recent years, the Angiotensin-(1-7)/Mas receptor [Ang-(1-7)/Mas] sub-branch of the Renin-Angiotensin System (RAS) in the brain, and Angiotensin Type 2 Receptors (AT2R), have attracted scientific interest, as there is evidence that they constitute an essential pathway in cardiovascular regulation, in health and in disease. By acting centrally, the Ang-(1-7)/Mas axis - that has been termed 'the axis of good'- can exert blood pressure-lowering effects, while also favourably altering baroreflex sensitivity and noradrenergic neurotransmission. Thus, research has focused on the possible neuro- and cardioprotective effects of this pathway in the setting of cardiovascular disease, ultimately aiming to evaluate the potential for development of novel therapeutic strategies based on its modulation. We summarize the available evidence from experimental studies in this context, aiming to assess current limits of scientific knowledge relevant to this newly-described 'player' in haemodynamic regulation, that may become a potential therapeutic target.
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Affiliation(s)
- Vasiliki Katsi
- First Department of Cardiology, 'Hippokration' Hospital of Athens, University of Athens, Medical School, Athens, Greece
| | | | - Maria Marketou
- Cardiology Department, University Hospital of Heraklion, Heraklion, Greece
| | - Costas Tsioufis
- First Department of Cardiology, 'Hippokration' Hospital of Athens, University of Athens, Medical School, Athens, Greece
| | | | - Dimitrios Tousoulis
- First Department of Cardiology, 'Hippokration' Hospital of Athens, University of Athens, Medical School, Athens, Greece
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5
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Costa-Ferreira W, Gomes-de-Souza L, Crestani CC. AT2 and MAS (but not AT1) angiotensinergic receptors in the medial amygdaloid nucleus modulate the baroreflex activity in rats. Pflugers Arch 2019; 471:1173-1182. [DOI: 10.1007/s00424-019-02301-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/26/2019] [Accepted: 08/01/2019] [Indexed: 01/27/2023]
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6
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Santos RAS, Sampaio WO, Alzamora AC, Motta-Santos D, Alenina N, Bader M, Campagnole-Santos MJ. The ACE2/Angiotensin-(1-7)/MAS Axis of the Renin-Angiotensin System: Focus on Angiotensin-(1-7). Physiol Rev 2018; 98:505-553. [PMID: 29351514 PMCID: PMC7203574 DOI: 10.1152/physrev.00023.2016] [Citation(s) in RCA: 722] [Impact Index Per Article: 120.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 05/09/2017] [Accepted: 06/18/2017] [Indexed: 12/16/2022] Open
Abstract
The renin-angiotensin system (RAS) is a key player in the control of the cardiovascular system and hydroelectrolyte balance, with an influence on organs and functions throughout the body. The classical view of this system saw it as a sequence of many enzymatic steps that culminate in the production of a single biologically active metabolite, the octapeptide angiotensin (ANG) II, by the angiotensin converting enzyme (ACE). The past two decades have revealed new functions for some of the intermediate products, beyond their roles as substrates along the classical route. They may be processed in alternative ways by enzymes such as the ACE homolog ACE2. One effect is to establish a second axis through ACE2/ANG-(1-7)/MAS, whose end point is the metabolite ANG-(1-7). ACE2 and other enzymes can form ANG-(1-7) directly or indirectly from either the decapeptide ANG I or from ANG II. In many cases, this second axis appears to counteract or modulate the effects of the classical axis. ANG-(1-7) itself acts on the receptor MAS to influence a range of mechanisms in the heart, kidney, brain, and other tissues. This review highlights the current knowledge about the roles of ANG-(1-7) in physiology and disease, with particular emphasis on the brain.
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Affiliation(s)
- Robson Augusto Souza Santos
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Walkyria Oliveira Sampaio
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Andreia C Alzamora
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Daisy Motta-Santos
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Natalia Alenina
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Michael Bader
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
| | - Maria Jose Campagnole-Santos
- National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais , Belo Horizonte , Brazil ; Department of Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil ; Max-Delbrück-Center for Molecular Medicine (MDC), Berlin , Germany ; Berlin Institute of Health (BIH), Berlin , Germany ; Charité - University Medicine, Berlin , Germany ; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin , Germany ; Institute for Biology, University of Lübeck , Lübeck , Germany
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7
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Soares ER, Barbosa CM, Campagnole-Santos MJ, Santos RAS, Alzamora AC. Hypotensive effect induced by microinjection of Alamandine, a derivative of angiotensin-(1-7), into caudal ventrolateral medulla of 2K1C hypertensive rats. Peptides 2017; 96:67-75. [PMID: 28889964 DOI: 10.1016/j.peptides.2017.09.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/03/2017] [Accepted: 09/04/2017] [Indexed: 01/11/2023]
Abstract
In the present study we evaluated the cardiovascular effects produced by microinjection of the new component of the renin-angiotensin system, alamandine, into caudal ventrolateral medulla of urethane-anesthetized normotensive and hypertensive 2K1C rats. The participation of different angiotensin receptors in the effects of alamandine was also evaluated. Microinjection of angiotensin-(1-7) was used for comparison. The microinjection of 4, 40 and 140pmol of alamandine or angiotensin-(1-7) into caudal ventrolateral medulla induced similar hypotensive effects in Sham-operated rats. However, contrasting with angiotensin-(1-7), in 2K1C rats the MAP response to the highest dose of alamandine was similar to that observed with saline. The microinjection of A-779, a selective Mas receptor antagonist, blunted the angiotensin-(1-7) effects but did not block the hypotensive effect of alamandine in Sham or in 2K1C rats. However, microinjection of D-Pro7-angiotensin-(1-7), a Mas/MrgD receptor antagonist, blocked the hypotensive effect induced by both peptides. Furthermore, microinjection of PD123319, a putative AT2 receptor antagonist blocked the hypotensive effect of alamandine, but not of angiotensin-(1-7), in Sham and 2K1C rats. Microinjection of the AT1 receptor antagonist, losartan, did not alter the hypotensive effect of angiotensin-(1-7) or alamandine in both groups. These results provide new insights about the differential mechanisms participating in the central cardiovascular effects of alamandine and angiotensin-(1-7) in normotensive and 2K1C hypertensive rats.
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Affiliation(s)
- E R Soares
- Núcleo de Pesquisa em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Inovação Nanobiofarmacêutica, Brazil
| | - C M Barbosa
- Núcleo de Pesquisa em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Inovação Nanobiofarmacêutica, Brazil
| | - M J Campagnole-Santos
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Inovação Nanobiofarmacêutica, Brazil
| | - R A S Santos
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Inovação Nanobiofarmacêutica, Brazil.
| | - A C Alzamora
- Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil; Núcleo de Pesquisa em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil; Instituto Nacional de Ciência e Tecnologia em Inovação Nanobiofarmacêutica, Brazil.
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8
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Huber G, Schuster F, Raasch W. Brain renin-angiotensin system in the pathophysiology of cardiovascular diseases. Pharmacol Res 2017; 125:72-90. [PMID: 28687340 DOI: 10.1016/j.phrs.2017.06.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/28/2017] [Accepted: 06/28/2017] [Indexed: 02/07/2023]
Abstract
Cardiovascular diseases (CVD) are among the main causes of death globally and in this context hypertension represents one of the key risk factors for developing a CVD. It is well established that the peripheral renin-angiotensin system (RAS) plays an important role in regulating blood pressure (BP). All components of the classic RAS can also be found in the brain but, in contrast to the peripheral RAS, how the endogenous RAS is involved in modulating cardiovascular effects in the brain is not fully understood yet. It is a complex system that may work differently in diverse areas of the brain and is linked to the peripheral system by the circumventricular organs (CVO), which do not have a blood brain barrier (BBB). In this review, we focus on the brain angiotensin peptides, their interactions with each other, and the consequences in the central nervous system (CNS) concerning cardiovascular control. Additionally, we present potential drug targets in the brain RAS for the treatment of hypertension.
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Affiliation(s)
- Gianna Huber
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany; CBBM (Center of Brain, Behavior and Metabolism), Lübeck, Germany
| | - Franziska Schuster
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany; CBBM (Center of Brain, Behavior and Metabolism), Lübeck, Germany
| | - Walter Raasch
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany; CBBM (Center of Brain, Behavior and Metabolism), Lübeck, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.
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9
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Schütten MTJ, Houben AJHM, de Leeuw PW, Stehouwer CDA. The Link Between Adipose Tissue Renin-Angiotensin-Aldosterone System Signaling and Obesity-Associated Hypertension. Physiology (Bethesda) 2017; 32:197-209. [PMID: 28404736 DOI: 10.1152/physiol.00037.2016] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 11/22/2022] Open
Abstract
Obese individuals frequently develop hypertension, which is for an important part attributable to renin-angiotensin-aldosterone system (RAAS) overactivity. This review summarizes preclinical and clinical evidence on the involvement of dysfunctional adipose tissue in RAAS activation and on the renal, central, and vascular mechanisms linking RAAS components to obesity-associated hypertension.
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Affiliation(s)
- Monica T J Schütten
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Alfons J H M Houben
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Peter W de Leeuw
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Coen D A Stehouwer
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
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10
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Dartora DR, Irigoyen MC, Casali KR, Moraes-Silva IC, Bertagnolli M, Bader M, Santos RAS. Improved cardiovascular autonomic modulation in transgenic rats expressing an Ang-(1-7)-producing fusion protein. Can J Physiol Pharmacol 2017; 95:993-998. [PMID: 28459154 DOI: 10.1139/cjpp-2016-0557] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Angiotensin-(1-7) counterbalances angiotensin II cardiovascular effects. However, it has yet to be determined how cardiovascular autonomic modulation may be affected by chronic and acute elevation of Ang-(1-7). Hemodynamics and cardiovascular autonomic profile were evaluated in male Sprague-Dawley (SD) rats and transgenic rats (TGR) overexpressing Ang-(1-7) [TGR(A1-7)3292]. Blood pressure (BP) was directly measured while cardiovascular autonomic modulation was evaluated by spectral analysis. TGR received A-779 or vehicle and SD rats received Ang-(1-7) or vehicle and were monitored for 5 h after i.v. administration. In another set of experiments with TGR, A-779 was infused for 7 days using osmotic mini pumps. Although at baseline no differences were observed, acute administration of A-779 in TGR produced a marked long-lasting increase in BP accompanied by increased BP variability (BPV) and sympathetic modulation to the vessels. Likewise, chronic administration of A-779 with osmotic mini pumps in TGR increased heart rate, sympathovagal balance, BPV, and sympathetic modulation to the vessels. Administration of Ang-(1-7) to SD rats increased heart rate variability values in 88% accompanied by 8% of vagal modulation increase and 18% of mean BP reduction. These results show that both acute and chronic alteration in the Ang-(1-7)-Mas receptor axis may lead to important changes in the autonomic control of circulation, impacting either sympathetic and (or) parasympathetic systems.
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Affiliation(s)
- Daniela Ravizzoni Dartora
- a Cardiology Institute of Rio Grande do Sul/University Foundation of Cardiology, Porto Alegre, Rio Grande do Sul, Brazil
| | - Maria-Claudia Irigoyen
- a Cardiology Institute of Rio Grande do Sul/University Foundation of Cardiology, Porto Alegre, Rio Grande do Sul, Brazil.,b Heart Institute (InCor), University of São Paulo Medical School, São Paulo, São Paulo, Brazil
| | - Karina Rabello Casali
- a Cardiology Institute of Rio Grande do Sul/University Foundation of Cardiology, Porto Alegre, Rio Grande do Sul, Brazil.,c Federal University of São Paulo (UNIFESP), Science and Technology Institute (ICT), São José dos Campos, São Paulo, Brazil
| | - Ivana C Moraes-Silva
- b Heart Institute (InCor), University of São Paulo Medical School, São Paulo, São Paulo, Brazil
| | | | - Michael Bader
- e Max-Delbruck Center of Molecular Medicine (MDC), Berlin-Buch, Germany
| | - Robson A S Santos
- a Cardiology Institute of Rio Grande do Sul/University Foundation of Cardiology, Porto Alegre, Rio Grande do Sul, Brazil.,f National Institute of Science and Technology in Nanobiopharmaceutics, Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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11
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Sukumaran S, Patel HJ, Patel BM. Evaluation of role of telmisartan in combination with 5-fluorouracil in gastric cancer cachexia. Life Sci 2016; 154:15-23. [PMID: 27117583 DOI: 10.1016/j.lfs.2016.04.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/14/2016] [Accepted: 04/22/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND The objective of the present study was to evaluate the effect of combination of telmisartan with 5-flourouracil (5-FU) in gastric cancer cachexia induced by administering N-methyl-N'-methyl-N-nitrosoguanidine (MNNG). METHOD MNND was administered once daily by oral gavage for two weeks, and saturated NaCl (1ml per rat) was then given once every 3days for 4weeks. 5-FU (75mg/kg, i.v.) was administered once three weeks from 7th to 22nd week. From 7th to 22nd week, telmisartan (5mg/kg, p.o.) was also administered along with 5-FU. RESULT MNNG produced significant decrease in food intake, body weight, caused hyperglycemia, dyslipidemia, hypertension worsened hemodyanamics, increased cachexia markers and increased tumor markers like lactate dehydrogenase and γ-glutamyltransferase. MNNG also produced oxidative stress in the stomach tissue. Treatment with combination of telmisartan with 5-FU produced significant increase in food intake and body weight, controlled hyperglycemia and dyslipidemia, preserved hemodynamic function, and decreased the cachexia markers while 5-FU alone did not produce any such effects. Further, the combination of telmisartan with 5-FU significantly reduced tumor marker levels, oxidative stress and also significantly decreased the cell proliferation, apoptosis, hyperkeratosis, keratohyaline granules and invasive carcinoma of forestomach and reduced muscle atrophy in tibilias anterior skeletal muscle. CONCLUSION Our data suggests that combination of telmisartan with 5-FU treatment is beneficial in controlling cancer cachexia. Telmisartan can be used as an add-on therapy with 5-FU or other traditional chemotherapeutic agents.
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Exercise Training Improves the Altered Renin-Angiotensin System in the Rostral Ventrolateral Medulla of Hypertensive Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:7413963. [PMID: 26881037 PMCID: PMC4736418 DOI: 10.1155/2016/7413963] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 11/10/2015] [Accepted: 11/17/2015] [Indexed: 01/25/2023]
Abstract
The imbalance between angiotensin II (Ang II) and angiotensin 1-7 (Ang 1-7) in the brain has been reported to contribute to cardiovascular dysfunction in hypertension. Exercise training (ExT) is beneficial to hypertension and the mechanism is unclear. This study was aimed to determine if ExT improves hypertension via adjusting renin angiotensin system in cardiovascular centers including the rostral ventrolateral medulla (RVLM). Spontaneously hypertensive rats (SHR, 8 weeks old) were subjected to low-intensity ExT or kept sedentary (Sed) for 12 weeks. Blood pressure elevation coupled with increase in age was significantly decreased in SHR received ExT compared with Sed. The results in vivo showed that ExT significantly reduced or increased the cardiovascular responses to central application of sarthran (antagonist of Ang II) or A779 (antagonist of Ang 1-7), respectively. The protein expression of the Ang II acting receptor AT1R and the Ang 1-7 acting receptor Mas in the RVLM was significantly reduced and elevated in SHR following ExT, respectively. Moreover, production of reactive oxygen species in the RVLM was significantly decreased in SHR following ExT. The current data suggest that ExT improves hypertension via improving the balance of Ang II and Ang 1-7 and antioxidative stress at the level of RVLM.
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Hooper JS, Hadley SH, Morris KF, Breslin JW, Dean JB, Taylor-Clark TE. Characterization of cardiovascular reflexes evoked by airway stimulation with allylisothiocyanate, capsaicin, and ATP in Sprague-Dawley rats. J Appl Physiol (1985) 2015; 120:580-91. [PMID: 26718787 DOI: 10.1152/japplphysiol.00944.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/25/2015] [Indexed: 12/17/2022] Open
Abstract
Acute inhalation of airborne pollutants alters cardiovascular function and evidence suggests that pollutant-induced activation of airway sensory nerves via the gating of ion channels is critical to these systemic responses. Here, we have investigated the effect of capsaicin [transient receptor potential (TRP) vanilloid 1 (TRPV1) agonist], AITC [TRP ankyrin 1 (TRPA1) agonist], and ATP (P2X2/3 agonist) on bronchopulmonary sensory activity and cardiovascular responses of conscious Sprague-Dawley (SD) rats. Single fiber recordings show that allyl isothiocyanate (AITC) and capsaicin selectively activate C fibers, whereas subpopulations of both A and C fibers are activated by stimulation of P2X2/3 receptors. Inhalation of the agonists by conscious rats caused significant bradycardia, atrioventricular (AV) block, and prolonged PR intervals, although ATP-induced responses were lesser than those evoked by AITC or capsaicin. Responses to AITC were inhibited by the TRP channel blocker ruthenium red and the muscarinic antagonist atropine. AITC inhalation also caused a biphasic blood pressure response: a brief hypertensive phase followed by a hypotensive phase. Atropine accentuated the hypertensive phase, while preventing the hypotension. AITC-evoked bradycardia was not abolished by terazosin, the α1-adrenoceptor inhibitor, which prevented the hypertensive response. Anesthetics had profound effects on AITC-evoked bradycardia and AV block, which was abolished by urethane, ketamine, and isoflurane. Nevertheless, AITC inhalation caused bradycardia and AV block in paralyzed and ventilated rats following precollicular decerebration. In conclusion, we provide evidence that activation of ion channels expressed on nociceptive airway sensory nerves causes significant cardiovascular effects in conscious SD rats via reflex modulation of the autonomic nervous system.
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Affiliation(s)
- J S Hooper
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - S H Hadley
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - K F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - J W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - J B Dean
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - T E Taylor-Clark
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
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Kangussu LM, Guimaraes PS, Nadu AP, Melo MB, Santos RAS, Campagnole-Santos MJ. Activation of angiotensin-(1-7)/Mas axis in the brain lowers blood pressure and attenuates cardiac remodeling in hypertensive transgenic (mRen2)27 rats. Neuropharmacology 2015; 97:58-66. [PMID: 25983274 DOI: 10.1016/j.neuropharm.2015.04.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/20/2015] [Accepted: 04/30/2015] [Indexed: 11/27/2022]
Abstract
Activation of the peripheral angiotensin-(1-7)/Mas axis of the renin-angiotensin system produces important cardioprotective actions, counterbalancing the deleterious actions of an overactivity of Ang II/AT1 axis. In the present study we evaluated whether the chronic increase in Ang-(1-7) levels in the brain could ameliorate cardiac disorders observed in transgenic (mRen2)27 hypertensive rats through actions on Mas receptor. Sprague Dawley (SD) and transgenic (mRen2)27 hypertensive rats, instrumented with telemetry probe for arterial pressure (AP) measurement were subjected to 14 days of ICV infusion of Ang-(1-7) (200 ng/h) or Ang-(1-7) associated with Mas receptor antagonist (A779, 1 μg/h) or 0.9% sterile saline (0.5 μl/h) through osmotic mini-pumps. Ang-(1-7) infusion in (mRen2)27 rats reduced blood pressure, normalized the baroreflex control of HR, restored cardiac autonomic balance, reduced cardiac hypertrophy and pre-fibrotic alterations and decreased the altered imbalance of Ang II/Ang-(1-7) in the heart. In addition, there was an attenuation of the increased levels of atrial natriuretic peptide, brain natriuretic peptide, collagen I, fibronectin and TGF-β in the heart of (mRen2)27 rats. Furthermore, most of these effects were mediated in the brain by Mas receptor, since were blocked by its selective antagonist, A779. These data indicate that increasing Ang-(1-7) levels in the brain can attenuate cardiovascular disorders observed in (mRen2)27 hypertensive rats, probably by improving the autonomic balance to the heart due to centrally-mediated actions on Mas receptor.
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Affiliation(s)
- Lucas M Kangussu
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Priscila S Guimaraes
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Paula Nadu
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marcos B Melo
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Robson A S Santos
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Maria Jose Campagnole-Santos
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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Abstract
The RAS (renin-angiotensin system) is composed of two arms: the pressor arm containing AngII (angiotensin II)/ACE (angiotensin-converting enzyme)/AT1Rs (AngII type 1 receptors), and the depressor arm represented by Ang-(1-7) [angiotensin-(1-7)]/ACE2/Mas receptors. All of the components of the RAS are present in the brain. Within the brain, Ang-(1-7) contributes to the regulation of BP (blood pressure) by acting at regions that control cardiovascular function such that, when Ang-(1-7) is injected into the nucleus of the solitary tract, caudal ventrolateral medulla, paraventricular nucleus or anterior hypothalamic area, a reduction in BP occurs; however, when injected into the rostral ventrolateral medulla, Ang-(1-7) stimulates an increase in BP. In contrast with AngII, Ang-(1-7) improves baroreflex sensitivity and has an inhibitory neuromodulatory role in hypothalamic noradrenergic neurotransmission. Ang-(1-7) not only exerts effects related to BP regulation, but also acts as a cerebroprotective component of the RAS by reducing cerebral infarct size and neuronal apoptosis. In the present review, we provide an overview of effects elicited by Ang-(1-7) in the brain, which suggest a potential role for Ang-(1-7) in controlling the central development of hypertension.
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Jiang F, Yang J, Zhang Y, Dong M, Wang S, Zhang Q, Liu FF, Zhang K, Zhang C. Angiotensin-converting enzyme 2 and angiotensin 1-7: novel therapeutic targets. Nat Rev Cardiol 2014; 11:413-26. [PMID: 24776703 PMCID: PMC7097196 DOI: 10.1038/nrcardio.2014.59] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Angiotensin-converting enzyme (ACE) 2 and its product angiotensin 1–7 are thought to have effects that counteract the adverse actions of other, better-known renin–angiotensin system (RAS) components Numerous experimental studies have suggested that ACE2 and angiotensin 1–7 have notable protective effects in the heart and blood vessels ACE2-mediated catabolism of angiotensin II is likely to have a major role in cardiovascular protection, whereas the functional importance and signalling mechanisms of angiotensin-1–7-induced actions remain unclear New pharmacological interventions targeting ACE2 are expected to be useful in clinical treatment of cardiovascular disease, especially those associated with overactivation of the conventional RAS More studies, especially randomized controlled clinical trials, are needed to clearly delineate the benefits of therapies targeting angiotensin 1–7 actions
Angiotensin-converting enzyme 2, and its product angiotensin 1–7, are thought to have counteracting effects against the adverse actions of the better-known members of the renin–angiotensin system and might, therefore, be useful therapeutic targets in patients with cardiovascular disease. Professor Jiang and colleagues review the evidence for the potential roles of these proteins in various cardiovascular conditions, including hypertension, atherosclerosis, myocardial remodelling, heart failure, ischaemic stroke, and diabetes. The renin–angiotensin system (RAS) has pivotal roles in the regulation of normal physiology and the pathogenesis of cardiovascular disease. Angiotensin-converting enzyme (ACE) 2, and its product angiotensin 1–7, are thought to have counteracting effects against the adverse actions of other, better known and understood, members of the RAS. The physiological and pathological importance of ACE2 and angiotensin 1–7 in the cardiovascular system are not completely understood, but numerous experimental studies have indicated that these components have protective effects in the heart and blood vessels. Here, we provide an overview on the basic properties of ACE2 and angiotensin 1–7 and a summary of the evidence from experimental and clinical studies of various pathological conditions, such as hypertension, atherosclerosis, myocardial remodelling, heart failure, ischaemic stroke, and diabetes mellitus. ACE2-mediated catabolism of angiotensin II is likely to have a major role in cardiovascular protection, whereas the relevant functions and signalling mechanisms of actions induced by angiotensin 1–7 have not been conclusively determined. The ACE2–angiotensin 1–7 pathway, however, might provide a useful therapeutic target for the treatment of cardiovascular disease, especially in patients with overactive RAS.
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Affiliation(s)
- Fan Jiang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Jianmin Yang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Yongtao Zhang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Mei Dong
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Shuangxi Wang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Qunye Zhang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Fang Fang Liu
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Kai Zhang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
| | - Cheng Zhang
- Key Laboratory of Cardiovascular Remodelling and Function Research, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan 250012, Shandong Province, China
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Wainford RD. Angiotensin AT2 receptors and the baroreflex control of renal sympathetic nerve activity. Acta Physiol (Oxf) 2014; 210:714-6. [PMID: 24447624 DOI: 10.1111/apha.12240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. D. Wainford
- Department of Pharmacology & Experimental Therapeutics; Boston University School of Medicine; Boston MA USA
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Abdulla MH, Johns EJ. Nitric oxide impacts on angiotensin AT2 receptor modulation of high-pressure baroreflex control of renal sympathetic nerve activity in anaesthetized rats. Acta Physiol (Oxf) 2014; 210:832-44. [PMID: 24279649 PMCID: PMC3992911 DOI: 10.1111/apha.12207] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 09/30/2013] [Accepted: 11/19/2013] [Indexed: 11/28/2022]
Abstract
Aim Nitric oxide (NO) interacts with the local brain renin-angiotensin system to modulate sympathetic outflow and cardiovascular homoeostasis. This study investigated whether NO influenced the ability of angiotensin AT2 receptor activation to modify the high-pressure baroreceptor regulation of renal sympathetic nerve activity (RSNA) and heart rate (HR). Methods Anaesthetized (chloralose/urethane) rats were prepared to allow generation of baroreflex gain curves for RSNA or HR following intracerebroventricular (I.C.V.) CGP42112 (AT2 receptor agonist), PD123319 (AT2 receptor antagonist) or losartan (AT1 receptor antagonist), and then in combination with L-NAME (NO synthase inhibitor). Results I.C.V. PD123319, CGP42112, and Losartan did not change baseline mean arterial pressure, HR or RSNA. Baroreflex sensitivities for RSNA and HR were increased following AT2 receptor activation with CGP42112 by 112 and 157%, respectively, but were reduced following PD123319 by 20% (all P < 0.05). L-NAME alone increased baroreflex sensitivity for both RSNA and HR, by 62 and 158%, respectively, but when co-infused with either CGP42112 or PD123319, the baroreflex sensitivity fell to values comparable to those obtained during I.C.V. saline infusion. The baroreflex sensitivities for RSNA and HR were increased by losartan by 92% and 192%, respectively, but in the presence of L-NAME were no different from those obtained during I.C.V. saline infusion. Conclusion There is an important facilitatory role for AT2 receptors in the high-pressure baroreflex regulation of RSNA and HR which is dependent on a functional NO/NOS system. Conversely, AT1 receptors have an inhibitory effect on the baroreflex, an action that relies on a tonic inhibition of NO.
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Affiliation(s)
- M. H. Abdulla
- Department of Physiology Western Gateway Building University College Cork Cork Ireland
| | - E. J. Johns
- Department of Physiology Western Gateway Building University College Cork Cork Ireland
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Rosiglitazone increases cerebral klotho expression to reverse baroreflex in type 1-like diabetic rats. BIOMED RESEARCH INTERNATIONAL 2014; 2014:309151. [PMID: 24683546 PMCID: PMC3943406 DOI: 10.1155/2014/309151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 01/07/2014] [Indexed: 11/23/2022]
Abstract
Reduced baroreflex sensitivity (BRS) is widely observed in diabetic human and animals. Rosiglitazone is one of the clinically used thiazolidinediones (TZD) known as PPARγ agonist. Additionally, the klotho protein produced from choroid plexus in the central nervous system is regulated by PPARγ. In an attempt to develop the new therapeutic strategy, we treated streptozotocin-induced diabetic rats (STZ) with rosiglitazone (STZ + TZD) orally at 10 mg/kg for 7 days. Also, STZ rats were subjected to intracerebroventricular (ICV) infusion of recombinant klotho at a dose of 3 μg/2.5 μL via syringe pump (8 μg/hr) daily for 7 days. The BRS and heart rate variability were then estimated under challenge with a depressor dose of sodium nitroprusside (50 μg/kg) or a pressor dose of phenylephrine (8 μg/kg) through an intravenous injection. Lower expression of klotho in medulla oblongata of diabetic rats was identified. Cerebral infusion of recombinant klotho or oral administration of rosiglitazone reversed BRS in diabetic rats. In conclusion, recovery of the decreased klotho in brain induced by rosiglitazone may restore the impaired BRS in diabetic rats. Thus, rosiglitazone is useful to reverse the reduced BRS through increasing cerebral klotho in diabetic disorders.
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Combination of telmisartan with cisplatin controls oral cancer cachexia in rats. BIOMED RESEARCH INTERNATIONAL 2013; 2013:642848. [PMID: 24381940 PMCID: PMC3870111 DOI: 10.1155/2013/642848] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/09/2013] [Accepted: 09/01/2013] [Indexed: 12/28/2022]
Abstract
The objective of the present investigation was to study the effect of combination of telmisartan with cisplatin in oral cancer cachexia induced by applying 0.5% 4-nitroquinoline-1-oxide (4-NQO) in propylene glycol to tongue, thrice a week for 8 weeks. From 8th to 22nd week, cisplatin (0.23 mg/kg, i.v.) was administered once in three weeks and telmisartan (5 mg/kg/day, p.o.) was administered daily. 4-NQO produced significant decrease in food intake, body weight, hyperglycemia, dyslipidemia, hypertension, and bradycardia, worsened hemodyanamics, increased cachexia markers like insulin, C-reactive protein, and interleukin-6, and increased tumor markers like lactate dehydrogenase and γ-glutamyl transferase.Treatment with combination of telmisartan with cisplatin produced significant increase in food intake and body weight and controlled hyperglycaemia and dyslipidemia, preserved hemodynamic function, and decreased the cachexia markers while cisplatin alone did not produce any increase in food intake and body weight. Further, the combination of telmisartan with cisplatin significantly reduced tumor marker levels. Combination of telmisartan with cisplatin prevented 4-NQO induced oxidative stress, hyperplasia and hyperkeratosis, premalignant dysplasia, and invasive squamous cell carcinoma in the tongue. Our data suggests that combination of telmisartan with cisplatin treatment is beneficial in controlling cancer cachexia. Telmisartan can be used as an add-on therapy with cisplatin or other traditional chemotherapeutic agents.
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Marshall AC, Shaltout HA, Pirro NT, Rose JC, Diz DI, Chappell MC. Antenatal betamethasone exposure is associated with lower ANG-(1-7) and increased ACE in the CSF of adult sheep. Am J Physiol Regul Integr Comp Physiol 2013; 305:R679-88. [PMID: 23948771 PMCID: PMC3798802 DOI: 10.1152/ajpregu.00321.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/07/2013] [Indexed: 01/03/2023]
Abstract
Antenatal betamethasone (BM) therapy accelerates lung development in preterm infants but may induce early programming events with long-term cardiovascular consequences. To elucidate these events, we developed a model of programming whereby pregnant ewes are administered BM (2 doses of 0.17 mg/kg) or vehicle at the 80th day of gestation and offspring are delivered at term. BM-exposed (BMX) offspring develop elevated blood pressure; decreased baroreflex sensitivity; and alterations in the circulating, renal, and brain renin-angiotensin systems (RAS) by 6 mo of age. We compared components of the choroid plexus fourth ventricle (ChP4) and cerebral spinal fluid (CSF) RAS between control and BMX male offspring at 6 mo of age. In the choroid plexus, high-molecular-weight renin protein and ANG I-intact angiotensinogen were unchanged between BMX and control animals. Angiotensin-converting enzyme 2 (ACE2) activity was threefold higher than either neprilysin (NEP) or angiotensin 1-converting enzyme (ACE) in control and BMX animals. Moreover, all three enzymes were equally enriched by approximately 2.5-fold in ChP4 brush-border membrane preparations. CSF ANG-(1-7) levels were significantly lower in BMX animals (351.8 ± 76.8 vs. 77.5 ± 29.7 fmol/mg; P < 0.05) and ACE activity was significantly higher (6.6 ± 0.5 vs. 8.9 ± 0.5 fmol·min(-1)·ml(-1); P < 0.05), whereas ACE2 and NEP activities were below measurable limits. A thiol-sensitive peptidase contributed to the majority of ANG-(1-7) metabolism in the CSF, with higher activity in BMX animals. We conclude that in utero BM exposure alters CSF but not ChP RAS components, resulting in lower ANG-(1-7) levels in exposed animals.
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Affiliation(s)
- Allyson C Marshall
- Hypertension and Vascular Research Center, Wake Forest School of Medicine, Winston Salem, North Carolina
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Abstract
Aging is associated with an imbalance in sympathetic and parasympathetic outflow to cardiovascular effector organs. This autonomic imbalance contributes to the decline in cardiovagal baroreceptor reflex function during aging, which allows for unrestrained activation of the sympathetic nervous system to negatively impact resting systolic blood pressure and its variability. Further, impaired baroreflex function can contribute to the development of insulin resistance and other features of the metabolic syndrome during aging through overlap in autonomic neural pathways that regulate both cardiovascular and metabolic functions. Increasing evidence supports a widespread influence of the renin-angiotensin system (RAS) on both sympathetic and parasympathetic activity through receptors distributed to peripheral and central sites of action. Indeed, therapeutic interventions to block the RAS are well established for the treatment of hypertension in elderly patients, and reduce the incidence of new-onset diabetes in clinical trials. Further, RAS blockade increases lifespan and improves numerous age-related pathologies in rodents, often independent of blood pressure. The beneficial effects of these interventions are at least in part attributed to suppression of angiotensin II formed locally within the brain. In particular, recent insights from transgenic rodents provide evidence that long-term alteration in the brain RAS modulates the balance between angiotensin II and angiotensin-(1-7), and related intracellular signaling pathways, to influence cardiovascular and metabolic function in the context of hypertension and aging.
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Protein phosphatase 1b in the solitary tract nucleus is necessary for normal baroreflex function. J Cardiovasc Pharmacol 2012; 59:472-8. [PMID: 22569287 DOI: 10.1097/fjc.0b013e31824ba490] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Despite positive metabolic effects, genetic deletion of protein phosphatase 1b (PTP1b) results in sympathetically mediated elevations in arterial pressure (AP) in mice. Because several PTP1b-regulated peptides also impair the baroreflex sensitivity (BRS) for control of heart rate (HR), we hypothesized that PTP1b in the solitary tract nucleus (NTS) participates in the maintenance of resting baroreflex function. To test this hypothesis, we performed acute bilateral microinjection of an allosteric PTP1b inhibitor (100 nM/120 nL) in the NTS of urethane/chloralose anesthetized Sprague-Dawley rats and assessed the BRS, responses to cardiac vagal chemosensitive fiber activation, and resting AP and HR before and after the injection. PTP1b inhibition impaired the BRS for bradycardia (n = 6; 0.93 ± 0.14 baseline vs. 0.48 ± 0.04 at 10 minutes vs. 0.49 ± 0.04 millisecond/mm Hg at 60 minutes; P < 0.01), with no significant effect on the BRS for tachycardia (0.30 ± 0.16 baseline vs. 0.24 ± 0.08 at 10 minutes vs. 0.24 ± 0.12 millisecond/mm Hg at 60 minutes). The reduced BRS for bradycardia was associated with a significant decrease in alpha-adrenergic responsiveness to phenylephrine at 60 minutes after PTP1b inhibition. Injection of the PTP1b inhibitor in the NTS elicited transient decreases in AP and HR in these animals. However, there was no effect of the inhibitor on depressor or bradycardic responses elicited by activation of cardiac vagal chemosensitive fibers, which converge with baroreceptor afferents in the NTS. These results suggest that PTP1b within the NTS may be a novel molecular mechanism for preservation of resting baroreflex function and provides further evidence for deleterious cardiovascular effects associated with PTP1b inhibition.
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Arnold AC, Sakima A, Kasper SO, Vinsant S, Garcia-Espinosa MA, Diz DI. The brain renin-angiotensin system and cardiovascular responses to stress: insights from transgenic rats with low brain angiotensinogen. J Appl Physiol (1985) 2012; 113:1929-36. [PMID: 22984245 DOI: 10.1152/japplphysiol.00569.2012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renin-angiotensin system (RAS) has been identified as an attractive target for the treatment of stress-induced cardiovascular disorders. The effects of angiotensin (ANG) peptides during stress responses likely result from an integration of actions by circulating peptides and brain peptides derived from neuronal and glial sources. The present review focuses on the contribution of endogenous brain ANG peptides to pathways involved in cardiovascular responses to stressors. During a variety of forms of stress, neuronal pathways in forebrain areas containing ANG II or ANG-(1-7) are activated to stimulate descending angiotensinergic pathways that increase sympathetic outflow to increase blood pressure. We provide evidence that glia-derived ANG peptides influence brain AT(1) receptors. This appears to result in modulation of the responsiveness of the neuronal pathways activated during stressors that elevate circulating ANG peptides to activate brain pathways involving descending hypothalamic projections. It is well established that increased cardiovascular reactivity to stress is a significant predictor of hypertension and other cardiovascular diseases. This review highlights the importance of understanding the impact of RAS components from the circulation, neurons, and glia on the integration of cardiovascular responses to stressors.
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Affiliation(s)
- Amy C Arnold
- The Hypertension & Vascular Research Center and the Departments of General Surgery and Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157-1032, USA
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Guimaraes PS, Santiago NM, Xavier CH, Velloso EPP, Fontes MAP, Santos RAS, Campagnole-Santos MJ. Chronic infusion of angiotensin-(1-7) into the lateral ventricle of the brain attenuates hypertension in DOCA-salt rats. Am J Physiol Heart Circ Physiol 2012; 303:H393-400. [DOI: 10.1152/ajpheart.00075.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Angiotensin-(ANG)-(1-7) is known by its central and peripheral actions, which mainly oppose the deleterious effects induced by accumulation of ANG II during pathophysiological conditions. In the present study we evaluated whether a chronic increase in ANG-(1-7) levels in the brain would modify the progression of hypertension. After DOCA-salt hypertension was induced for seven days, Sprague-Dawley rats were subjected to 14 days of intracerebroventricular (ICV) infusion of ANG-(1-7) (200 ng/h, DOCA-A7) or 0.9% sterile saline. As expected, on the 21st day, DOCA rats presented increased mean arterial pressure (MAP) (≈40%), and impaired baroreflex control of heart rate (HR) and baroreflex renal sympathetic nerve activity (RSNA) in comparison with that in normotensive control rats (CTL). These changes were followed by an overactivity of the cardiac sympathetic tone and reduction of the cardiac parasympathetic tone, and exaggerated mRNA expression of collagen type I (≈9-fold) in the left ventricle. In contrast, DOCA rats treated with ANG-(1-7) ICV had an improvement of baroreflex control of HR, which was even higher than that in CTL, and a restoration of the baroreflex control of RSNA, the balance of cardiac autonomic tone, and normalized mRNA expression of collagen type I in the left ventricle. Furthermore, DOCA-A7 had MAP lowered significantly. These effects were not accompanied by significant circulating or cardiac changes in angiotensin levels. Taken together, our data show that chronic increase in ANG-(1-7) in the brain attenuates the development of DOCA-salt hypertension, highlighting the importance of this peptide in the brain for the treatment of cardiovascular diseases.
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Affiliation(s)
- Priscila S. Guimaraes
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
| | - Nivia M. Santiago
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
| | - Carlos H. Xavier
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
| | - Elizabeth P. P. Velloso
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
| | - Marco A. P. Fontes
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
| | - Robson A. S. Santos
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
| | - Maria Jose Campagnole-Santos
- National Institute of Science and Technology-Nanobiofar, Department of Physiology and Biophysics, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, MG
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Perindopril protects against streptozotocin-induced hyperglycemic myocardial damage/alterations. Hum Exp Toxicol 2012; 31:1132-43. [DOI: 10.1177/0960327112446817] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
High blood pressure, obesity, abnormal lipid profile, which often coexist with diabetes, tend to be associated with preclinical cardiovascular abnormalities and may contribute to the association of diabetes with cardiovascular events. Many studies have proved that streptozotocin (STZ) is responsible for type-2-diabetes-induced cardiovascular complications. Long-term perindopril therapy in patients with hypertension and diabetes has been observed to correct carotid remodeling by reducing hypertrophy. We studied the effect of perindopril (1 mg/kg/d orally [po]) on cardiovascular complications in neonatal model of rats, which was induced by administering STZ (90 mg/kg, intraperitoneally [ip]), in 5-d-old wistar rats and cardiac hypertrophy induced by isoprenaline (ISO; 5 mg/kg, ip) for 10 d. Various biochemical, cardiac, and hemodynamic parameters were measured at the end of 8 weeks of treatment in diabetes model and 10 d in hypertrophy model. STZ produced hyperglycemia, hyperinsulinemia, dyslipidemia, hypertension, bradycardia, increased creatinine kinase (CK-MB), lactate dehydrogenase enzymes (LDH) and C-reactive protein (CRP) levels, cardiac hypertrophy, and oxidative stress. Chronic treatment with perindopril significantly prevented STZ-induced hyperglycemia and hyperinsulinemia and controlled dyslipdemia in diabetic rats. Further, perindopril produced a significant reduction in elevated levels of CRP, LDH, and CK. STZ-induced hypertension and bradycardia were also prevented by perindopril treatment. Perindopril also produced beneficial effect by preventing cardiac hypertrophy as evident from cardiac hypertrophy index and left ventricular hypertrophic index. Perindopril also prevented STZ-induced oxidative stress. Similar results were obtained in ISO-induced cardiac hypertrophic model, which confirms the beneficial role of perindopril in cardiac hypertrophy. In conclusion, our data from both studies suggest that perindopril produced beneficial effect on cardiac complications.
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Murça TM, Almeida TCS, Raizada MK, Ferreira AJ. Chronic activation of endogenous angiotensin-converting enzyme 2 protects diabetic rats from cardiovascular autonomic dysfunction. Exp Physiol 2012; 97:699-709. [PMID: 22286369 DOI: 10.1113/expphysiol.2011.063461] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this study, we evaluated whether the activation of endogenous angiotensin-converting enzyme 2 (ACE2) would improve the cardiovascular autonomic dysfunction of diabetic rats. Ten days after induction of type 1 diabetes (streptozotocin, 50 mg kg(-1) i.v.), the rats were treated orally with 1-[(2-dimethylamino)ethylamino]-4-(hydroxymethyl)-7-[(4-methylphenyl) sulfonyl oxy]-9H-xanthene-9-one (XNT), a newly discovered ACE2 activator (1 mg kg(-1) day(-1)), or saline (equivalent volume) for 30 days. Autonomic cardiovascular parameters were evaluated in conscious animals, and an isolated heart preparation was used to analyse cardiac function. Diabetes induced a significant decrease in the baroreflex bradycardia sensitivity, as well as in the chemoreflex chronotropic response and parasympathetic tone. The XNT treatment improved these parameters by ≈ 76% [0.82 ± 0.09 versus 1.44 ± 0.17 Ratio between changes in pulse interval and changes in mean arterial pressure (ΔPI/ΔmmHg)], ∼85% (-57 ± 9 versus -105 ± 10 beats min(-1)) and ≈ 205% (22 ± 2 versus 66 ± 12 beats min(-1)), respectively. Also, XNT administration enhanced the bradycardia induced by the chemoreflex activation by v 74% in non-diabetic animals (-98 ± 16 versus -170 ± 9 Δbeats min(-1)). No significant changes were observed in the mean arterial pressure, baroreflex tachycardia sensitivity, chemoreflex pressor response and sympathetic tone among any of the groups. Furthermore, chronic XNT treatment ameliorated the cardiac function of diabetic animals. However, the coronary vasoconstriction observed in diabetic rats was unchanged by ACE2 activation. These findings indicate that XNT protects against the autonomic and cardiac dysfunction induced by diabetes. Thus, our results provide evidence for the viability and effectiveness of oral administration of an ACE2 activator for the treatment of the cardiovascular autonomic dysfunction caused by diabetes.
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Affiliation(s)
- Tatiane M Murça
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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Huang BS, White RA, Bi L, Leenen FHH. Central infusion of aliskiren prevents sympathetic hyperactivity and hypertension in Dahl salt-sensitive rats on high salt intake. Am J Physiol Regul Integr Comp Physiol 2012; 302:R825-32. [PMID: 22262304 DOI: 10.1152/ajpregu.00368.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Central infusion of an angiotensin type 1 (AT(1)) receptor blocker prevents sympathetic hyperactivity and hypertension in Dahl salt-sensitive (S) rats on high salt. In the present study, we examined whether central infusion of a direct renin inhibitor exerts similar effects. Intracerebroventricular infusion of aliskiren at the rate of 0.05 mg/day markedly inhibited the increase in ANG II levels in the cerebrospinal fluid and in blood pressure (BP) caused by intracerebroventricular infusion of rat renin. In Dahl S rats on high salt, intracerebroventricular infusion of aliskiren at 0.05 and 0.25 mg/day for 2 wk similarly decreased resting BP in Dahl S rats on high salt. In other groups of Dahl S rats, high salt intake for 2 wk increased resting BP by ∼25 mmHg, enhanced pressor and sympathoexcitatory responses to air-stress, and desensitized arterial baroreflex function. All of these effects were largely prevented by intracerebroventricular infusion of aliskiren at 0.05 mg/day. Aliskiren had no effects in rats on regular salt. Neither high salt nor aliskiren affected hypothalamic ANG II content. These results indicate that intracerebroventricular infusions of aliskiren and an AT(1) receptor blocker are similarly effective in preventing salt-induced sympathetic hyperactivity and hypertension in Dahl S rats, suggesting that renin in the brain plays an essential role in the salt-induced hypertension. The absence of an obvious increase in hypothalamic ANG II by high salt, or decrease in ANG II by aliskiren, suggests that tissue levels do not reflect renin-dependent ANG II production in sympathoexcitatory angiotensinergic neurons.
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Affiliation(s)
- Bing S Huang
- Hypertension Unit, Univ. of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Nakagaki T, Hirooka Y, Ito K, Kishi T, Hoka S, Sunagawa K. Role of angiotensin-(1-7) in rostral ventrolateral medulla in blood pressure regulation via sympathetic nerve activity in Wistar-Kyoto and spontaneous hypertensive rats. Clin Exp Hypertens 2011; 33:223-30. [PMID: 21699448 DOI: 10.3109/10641963.2011.583967] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Angiotensin (Ang)-(1-7) Ang-(1-7) is formed from angiotensin II by angiotensin-converting enzyme 2 (ACE2) and modulates the renin-angiotensin system. We evaluated whether the Ang-(1-7)-Mas axis in the rostral ventrolateral medulla (RVLM) contributes to neural mechanisms of blood pressure (BP) regulation. We microinjected Ang-(1-7), Ang-(1-7)-Mas receptor antagonist A-779, and ACE2 inhibitor DX600 into the RVLM of anesthetized Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHRs). Unilateral Ang-(1-7) microinjection induced a significantly greater increase in AP (arterial blood pressure) in SHR than in WKY. Bilateral A-779 microinjection induced a significantly greater decrease in AP and renal sympathetic nerve activity in SHR than in WKY. Bilateral DX600 microinjection induced a significantly greater decrease in AP in SHR than in WKY. Our results suggest that endogenous Ang-(1-7) in the RVLM contributes to maintain AP and renal sympathetic nerve activity both in SHR and WKY and that its activity might be enhanced in SHR.
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Affiliation(s)
- Toshiaki Nakagaki
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
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Goyal BR, Parmar K, Goyal RK, Mehta AA. Beneficial role of telmisartan on cardiovascular complications associated with STZ-induced type 2 diabetes in rats. Pharmacol Rep 2011; 63:956-66. [DOI: 10.1016/s1734-1140(11)70611-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 02/18/2011] [Indexed: 12/26/2022]
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Yang RF, Yin JX, Li YL, Zimmerman MC, Schultz HD. Angiotensin-(1-7) increases neuronal potassium current via a nitric oxide-dependent mechanism. Am J Physiol Cell Physiol 2010; 300:C58-64. [PMID: 20980550 DOI: 10.1152/ajpcell.00369.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Actions of angiotensin-(1-7) [Ang-(1-7)], a heptapeptide of the renin-angiotensin system, in the periphery are mediated, at least in part, by activation of nitric oxide (NO) synthase (NOS) and generation NO(·). Studies of the central nervous system have shown that NO(·) acts as a sympathoinhibitory molecule and thus may play a protective role in neurocardiovascular diseases associated with sympathoexcitation, such as hypertension and heart failure. However, the contribution of NO in the intraneuronal signaling pathway of Ang-(1-7) and the subsequent modulation of neuronal activity remains unclear. Here, we tested the hypothesis that neuronal NOS (nNOS)-derived NO(·) mediates changes in neuronal activity following Ang-(1-7) stimulation. For these studies, we used differentiated catecholaminergic (CATH.a) neurons, which we show express the Ang-(1-7) receptor (Mas R) and nNOS. Stimulation of CATH.a neurons with Ang-(1-7) (100 nM) increased intracellular NO levels, as measured by 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM) fluorescence and confocal microscopy. This response was significantly attenuated in neurons pretreated with the Mas R antagonist (A-779), a nonspecific NOS inhibitor (nitro-L-arginine methyl ester), or an nNOS inhibitor (S-methyl-L-thiocitrulline, SMTC), but not by endothelial NOS (eNOS) or inhibitory NOS (iNOS) inhibition {L-N-5-(1-iminoethyl)ornithine (L-NIO) and 1400W, respectively}. To examine the effect of Ang-(1-7)-NO(·) signaling on neuronal activity, we recorded voltage-gated outward K(+) current (I(Kv)) in CATH.a neurons using the whole cell configuration of the patch-clamp technique. Ang-(1-7) significantly increased I(Kv), and this response was inhibited by A-779 or S-methyl-L-thiocitrulline, but not L-NIO or 1400W. These findings indicate that Ang-(1-7) is capable of increasing nNOS-derived NO(·) levels, which in turn, activates hyperpolarizing I(Kv) in catecholaminergic neurons.
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Affiliation(s)
- Rui-Fang Yang
- University of Nebraska Medical Center, Omaha, 68198-5850, USA
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32
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de Moura MM, dos Santos RAS, Campagnole-Santos MJ, Todiras M, Bader M, Alenina N, Haibara AS. Altered cardiovascular reflexes responses in conscious Angiotensin-(1-7) receptor Mas-knockout mice. Peptides 2010; 31:1934-9. [PMID: 20603170 DOI: 10.1016/j.peptides.2010.06.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 06/23/2010] [Accepted: 06/24/2010] [Indexed: 11/21/2022]
Abstract
This study evaluated the physiological importance of Angiotensin-(1-7) receptor Mas on reflex control of circulation. Experiments were performed in male Mas-knockout (Mas-KO) and Wild Type (WT) conscious mice (12-20 wk of age). Baroreceptor reflex was evaluated by the bradycardic response induced by phenylephrine (0.25 μg/5 μl, i.v.). Bezold-Jarisch reflex was evaluated by phenylbiguanide (0.5 μg/5 μl, i.v.) and chemoreflex by potassium cyanide (2.5 μg/5 μl, i.v.). Baseline mean arterial pressure was higher in Mas-KO (n=14) as compared with WT mice (n=18) (118±1 mmHg vs. 109±2 mmHg); however, heart rate was similar in both strains (615±30 bpm vs. 648±13 bpm). Baroreflex bradycardia was lower (0.78±0.44 ms/mmHg vs. 1.30±0.14 ms/mmHg) in Mas-KO compared with WT mice. The depressor (-17±5 mmHg vs. -45±6 mmHg) and bradycardic (-212±36 bpm vs. -391±29 bpm) components of the Bezold-Jarisch reflex were also lower in Mas-KO mice. In addition, chemoreflex pressor response (+20±3 mmHg vs. +12±0.8 mmHg) and bradycardic response (-250±74 bpm vs. -52±26 bpm) were significantly higher in Mas-KO. These results further advances previous studies by showing that the lack of Mas receptor induced important imbalance in the neural control of blood pressure, altering not only the baroreflex but also the chemo- and Bezold-Jarisch reflexes.
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Arnold AC, Isa K, Shaltout HA, Nautiyal M, Ferrario CM, Chappell MC, Diz DI. Angiotensin-(1-12) requires angiotensin converting enzyme and AT1 receptors for cardiovascular actions within the solitary tract nucleus. Am J Physiol Heart Circ Physiol 2010; 299:H763-71. [PMID: 20562338 DOI: 10.1152/ajpheart.00345.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The novel peptide, angiotensin (ANG)-(1-12), elicits a systemic pressor response and vasoconstriction. These effects are blocked by ANG converting enzyme (ACE) inhibitors or AT(1) receptor antagonists, suggesting a role as an ANG II precursor. However, ANG-(1-12) can serve as a substrate for either ANG II or ANG-(1-7) formation, depending on the local tissue enzymes. Although levels of ANG-(1-12) are higher than ANG I or ANG II in brain, the role and processing of this peptide for autonomic control of heart rate (HR) has yet to be considered. Thus we examined the effects of nucleus tractus solitarii (NTS) microinjection of ANG-(1-12) on baroreflex sensitivity for control of HR, resting arterial pressure (AP) and HR, and indexes of sympathovagal balance in urethane/chloralose anesthetized Sprague-Dawley rats. NTS injection of ANG-(1-12) (144 fmol/120 nl) significantly impaired the evoked baroreflex sensitivity to increases in AP [n = 7; 1.06 +/- 0.06 baseline vs. 0.44 +/- 0.07 ms/mmHg after ANG-(1-12)], reduced the vagal component of spontaneous baroreflex sensitivity and HR variability, and elicited a transient depressor response (P < 0.05). NTS pretreatment with an AT(1) receptor antagonist or ACE inhibitor prevented ANG-(1-12)-mediated autonomic and depressor responses. ANG-(1-12) immunostaining was observed in cells within the NTS of Sprague-Dawley rats, providing a potential intracellular source for the peptide. However, acute NTS injection of an ANG-(1-12) antibody did not alter resting baroreflex sensitivity, AP, or HR in these animals. Collectively, these findings suggest that exogenous ANG-(1-12) is processed to ANG II for cardiovascular actions at AT(1) receptors within the NTS. The lack of acute endogenous ANG-(1-12) tone for cardiovascular regulation in Sprague-Dawley rats contrasts with chronic immunoneutralization in hypertensive rats, suggesting that ANG-(1-12) may be activated only under hypertensive conditions.
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Affiliation(s)
- Amy C Arnold
- Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1032, USA
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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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Cangussu LM, de Castro UGM, do Pilar Machado R, Silva ME, Ferreira PM, dos Santos RAS, Campagnole-Santos MJ, Alzamora AC. Angiotensin-(1-7) antagonist, A-779, microinjection into the caudal ventrolateral medulla of renovascular hypertensive rats restores baroreflex bradycardia. Peptides 2009; 30:1921-7. [PMID: 19577603 DOI: 10.1016/j.peptides.2009.06.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 06/24/2009] [Accepted: 06/24/2009] [Indexed: 12/17/2022]
Abstract
In the present study we evaluated the effect of caudal ventrolateral medulla (CVLM) microinjection of the main angiotensin (Ang) peptides, Ang II and Ang-(1-7), and their selective antagonists on baseline arterial pressure (AP) and on baroreceptor-mediated bradycardia in renovascular hypertensive rats (2K1C). Microinjection of Ang II and Ang-(1-7) into the CVLM of 2K1C rats produced similar decrease in AP as observed in Sham rats. In both Sham and 2K1C, the hypotensive effect of Ang II and Ang-(1-7) at the CVLM was blocked, for up to 30 min, by previous CVLM microinjection of the Ang II AT1 receptor antagonist, Losartan, and Ang-(1-7) Mas antagonist, A-779, respectively. As expected, the baroreflex bradycardia was lower in 2K1C in comparison to Sham rats. CVLM microinjection of A-779 improved the sensitivity of baroreflex bradycardia in 2K1C hypertensive rats. In contrast, Losartan had no effect on the baroreflex bradycardia in either 2K1C or Sham rats. These results suggest that Ang-(1-7) at the CVLM may contribute to the low sensitivity of the baroreflex control of heart rate in renovascular hypertensive rats.
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Affiliation(s)
- Luiza Michelle Cangussu
- Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
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Angiotensin-(1-7) and baroreflex function in nucleus tractus solitarii of (mRen2)27 transgenic rats. J Cardiovasc Pharmacol 2008; 51:542-8. [PMID: 18475201 DOI: 10.1097/fjc.0b013e3181734a54] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Endogenous angiotensin (Ang)-(1-7) enhances, while Ang II attenuates, baroreceptor sensitivity (BRS) for reflex control of heart rate (HR) in Sprague-Dawley (SD) rats. In (mRen2)27 renin transgenic rats [(mRen2)], there is overexpression of the mouse Ren2 gene in brain, leading to elevated Ang II and reduced Ang-(1-7) in brain medullary, and associated with hypertension and impaired BRS. METHODS We therefore tested the contribution of endogenous Ang-(1-7) to BRS for control of HR and responses to cardiac vagal chemosensitive afferent fiber activation (CVA) with phenylbiguanide (PBG) in anesthetized SD and (mRen2) 27 rats before and after bilateral nucleus of the solitary tract (nTS) injection of the Ang-(1-7) receptor antagonist (D-Ala7)-Ang-(1-7). RESULTS (mRen2) 27 rats exhibited a approximately 50% impairment in BRS as compared with SD (P < 0.05). (D-Ala7)-Ang-(1-7) attenuated BRS by approximately 50% in SD rats, but was without effect in (mRen2) 27 rats. (D-Ala7)-Ang-(1-7) did not alter the responses to CVA by PBG (iv bolus) in either strain. There were no differences in the depressor effects of Ang-(1-7) injected into the nTS, nor were levels of mRNA different for angiotensin-converting enzyme, angiotensin-converting enzyme 2, neprilysin, or the mas receptor in medullary tissue from SD versus (mRen2)27 rats. CONCLUSION Endogenous Ang-(1-7) does not provide tonic input in the nTS to modulate BRS for control of HR in (mRen2)27 rats, which may contribute to impairment of BRS in these animals.
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Varagic J, Trask AJ, Jessup JA, Chappell MC, Ferrario CM. New angiotensins. J Mol Med (Berl) 2008; 86:663-71. [PMID: 18437333 PMCID: PMC2713173 DOI: 10.1007/s00109-008-0340-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 02/28/2008] [Accepted: 02/29/2008] [Indexed: 12/22/2022]
Abstract
Accumulation of a large body of evidence during the past two decades testifies to the complexity of the renin–angiotensin system (RAS). The incorporation of novel enzymatic pathways, resulting peptides, and their corresponding receptors into the biochemical cascade of the RAS provides a better understanding of its role in the regulation of cardiovascular and renal function. Hence, in recent years, it became apparent that the balance between the two opposing effector peptides, angiotensin II and angiotensin-(1-7), may have a pivotal role in determining different cardiovascular pathophysiologies. Furthermore, our recent studies provide evidence for the functional relevance of a newly discovered rat peptide, containing two additional amino acid residues compared to angiotensin I, first defined as proangiotensin-12 [angiotensin-(1-12)]. This review focuses on angiotensin-(1-7) and its important contribution to cardiovascular function and growth, while introducing angiotensin-(1-12) as a potential novel angiotensin precursor.
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Affiliation(s)
- Jasmina Varagic
- The Hypertension and Vascular Research Center, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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38
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Effect of telmisartan on cardiovascular complications associated with streptozotocin diabetic rats. Mol Cell Biochem 2008; 314:123-31. [DOI: 10.1007/s11010-008-9772-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 04/07/2008] [Indexed: 10/22/2022]
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Caligiorne SM, Silva AQG, Fontes MAP, Silva JR, Baltatu O, Bader M, Santos RAS, Campagnole-Santos MJ. Baroreflex control of heart rate and renal sympathetic nerve activity in rats with low brain angiotensinogen. Neuropeptides 2008; 42:159-68. [PMID: 18242696 DOI: 10.1016/j.npep.2007.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 12/13/2007] [Accepted: 12/15/2007] [Indexed: 01/30/2023]
Abstract
The main objective of the present study was to evaluate baroreceptor control of heart rate (HR) and renal sympathetic nerve activity (RSNA) in transgenic rats (TG) with low angiotensinogen production in glial cells, TGR(ASrAogen)-680. In addition, the sympathetic and vagal autonomic tonus to the heart was investigated. As previously shown, TG rats presented a lower arterial pressure (AP) and HR. However, TG rats had decreased AP variability during the night (8.9+/-0.4 mmHg vs 9.8+/-0.3 mmHg, in SD) accompanied by an increase in HR variability (39+/-1 beats/min vs 35+/-1 beats/min, in SD) and augmented locomotor activity during the night (3.5+/-0.3 counts/min vs 2.5+/-0.2 counts/min, in SD). In addition, TG rats presented increased baroreflex sensitivity for the RSNA (slope of line that correlates decreases in RSNA and increases in AP=1.36+/-0.18 vs 0.77+/-0.1, in SD) and an increased sensitivity for both the baroreflex bradycardia (0.79+/-0.04 ms/mmHg vs 0.52+/-0.04 ms/mmHg, in SD) and tachycardia (1.46+/-0.1 ms/mmHg vs 0.93+/-0.01 ms/mmHg, in SD). Further, TG rats had increased vagal tonus (25+/-3 beats/min vs 11+/-4 beats/min in SD) without significant change in the sympathetic tonus to the heart. These results confirm and extend previous observations showing that glial angiotensinogen, the main source of brain RAS peptides, importantly modulates sympathetic tonus, at least to the renal nerve, and vagal tonus to the heart.
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Affiliation(s)
- Sordaini M Caligiorne
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627-ICB, 31270-901 Belo Horizonte, MG, Brazil
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40
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Diz DI, Garcia-Espinosa MA, Gegick S, Tommasi EN, Ferrario CM, Ann Tallant E, Chappell MC, Gallagher PE. Injections of angiotensin-converting enzyme 2 inhibitor MLN4760 into nucleus tractus solitarii reduce baroreceptor reflex sensitivity for heart rate control in rats. Exp Physiol 2008; 93:694-700. [PMID: 18356558 DOI: 10.1113/expphysiol.2007.040261] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Injections of the angiotensin(1-7) [Ang(1-7)] antagonist [d-Ala7]-Ang(1-7) into the nucleus of the solitary tract (NTS) of Sprague-Dawley rats reduce baroreceptor reflex sensitivity (BRS) for control of heart rate by approximately 40%, whereas injections of the angiotensin II (Ang II) type 1 receptor antagonist candesartan increase BRS by 40% when reflex bradycardia is assessed. The enzyme angiotensin-converting enzyme 2 (ACE2) is known to convert Ang II to Ang(1-7). We report that ACE2 activity, as well as ACE and neprilysin activities, are present in plasma membrane fractions of the dorsomedial medulla of Sprague-Dawley rats. Moreover, we show that BRS for reflex bradycardia is attenuated (1.16 +/- 0.29 ms mmHg-1 before versus 0.33 +/- 0.11 ms mmHg-1 after; P < 0.05; n = 8) 30-60 min following injection of the selective ACE2 inhibitor MLN4760 (12 pmol in 120 nl) into the NTS. These findings support the concept that within the NTS, local synthesis of Ang(1-7) from Ang II is required for normal sensitivity for the baroreflex control of heart rate in response to increases in arterial pressure.
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Affiliation(s)
- Debra I Diz
- The Hypertension & Vascular Research Center, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1032, USA.
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41
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Gao XY, Huang XL, Wang HJ, Zhou LM, Xu Y, Wang W, Zhu GQ. Depressor effect of closed-loop chip system in spontaneously hypertensive rats. Auton Neurosci 2007; 137:84-91. [PMID: 17913591 DOI: 10.1016/j.autneu.2007.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 09/02/2007] [Accepted: 09/04/2007] [Indexed: 11/25/2022]
Abstract
We previously reported that a closed-loop chip system was designed to decrease arterial pressure in normal rabbits and rats. In the present study, the depressor effects of the chip system were investigated in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). The arterial pressure was recorded, sampled, operated and processed in the chip system. The chip system instantaneously controlled arterial pressure by stimulating the left aortic depressor nerve according to the feedback signals of arterial pressure. The closed-loop chip system effectively decreased mean arterial pressure (MAP) and heart rate (HR) in both SHR and WKY rats. It decreased the duration and the maximal MAP level of the pressor response evoked by either intravenous injection of phenylephrine or cutaneous nociceptive stimulation in SHR, but had no significant effect on the magnitude of the increase in MAP. Furthermore, the chip system significantly increased the baroreflex gain in SHR, but not in normal WKY rats. These results suggest that the closed-loop chip system effectively decreases the arterial pressure and increases baroreflex gain in SHR. The chip system does not abolish the arterial pressure responses to accidental pressor events, but decreases the duration and the maximal MAP level of the pressor responses.
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Affiliation(s)
- Xing-Ya Gao
- Department of Physiology, Nanjing Medical University, Nanjing 210029, China
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42
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Trask AJ, Ferrario CM. Angiotensin-(1-7): pharmacology and new perspectives in cardiovascular treatments. ACTA ACUST UNITED AC 2007; 25:162-74. [PMID: 17614938 DOI: 10.1111/j.1527-3466.2007.00012.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Many advances have been made in the cardiovascular field in the last several decades. Among them is the progress completed to date on the heptapeptide member of the renin-angiotensin system (RAS), angiotensin-(1-7) [Ang-(1-7)]. The peptide's beneficial actions against pathophysiological processes, such as cardiac arrhythmia, heart failure, hypertension, renal disease, preeclampsia, and even cancer are continuously being uncovered. This review encompasses the pharmacology of Ang-(1-7) and expounds upon the peptide's potential as a therapeutic agent against pathological processes both within and outside the cardiovascular continuum.
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Affiliation(s)
- Aaron J Trask
- The Hypertension and Vascular Research Center, Wake Forest University Health Science Center, Winston-Salem, North Carolina 27157, USA.
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Sakima A, Averill DB, Kasper SO, Jackson L, Ganten D, Ferrario CM, Gallagher PE, Diz DI. Baroreceptor reflex regulation in anesthetized transgenic rats with low glia-derived angiotensinogen. Am J Physiol Heart Circ Physiol 2006; 292:H1412-9. [PMID: 17085537 DOI: 10.1152/ajpheart.00984.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endogenous angiotensin (ANG) II and ANG-(1-7) act at the nucleus tractus solitarius (NTS) to differentially modulate neural control of the circulation. The role of these peptides endogenous to NTS on cardiovascular reflex function was investigated in transgenic rats with low brain angiotensinogen (Aogen) due to glial overexpression of an antisense to Aogen (ASrAOGEN) and in Sprague-Dawley (SD) rats. Arterial baroreceptor reflex sensitivity (BRS) for control of heart rate (HR) in response to increases in mean arterial pressure (MAP) was tested before and after bilateral microinjection of the angiotensin type 1 (AT(1)) receptor blocker candesartan or the ANG-(1-7) receptor blocker (d-Ala(7))-ANG-(1-7) into the NTS of urethane-chloralose-anesthetized ASrAOGEN and SD rats. Baseline MAP was higher in ASrAOGEN than in SD rats under anesthesia (P < 0.01). Injection of candesartan or (d-Ala(7))-ANG-(1-7) decreased MAP (P < 0.01) and HR (P < 0.05) in ASrAOGEN, but not SD, rats. The BRS at baseline was similar in ASrAOGEN and SD rats. Candesartan increased BRS by 41% in SD rats (P < 0.01) but was without effect in ASrAOGEN rats. In contrast, the reduction in BRS after (d-Ala(7))-ANG-(1-7) administration was comparable in SD (31%) and ASrAOGEN rats (34%). These findings indicate that the absence of glia-derived Aogen is associated with 1) an increase in MAP under anesthesia mediated via AT(1) and ANG-(1-7) receptors within the NTS, 2) the absence of an endogenous ANG II contribution to tonic inhibition of BRS, and 3) a continued contribution of endogenous ANG-(1-7) to tonic enhancement of BRS.
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Affiliation(s)
- Atsushi Sakima
- Hypertension & Vascular Disease Center, Wake Forest Univ School of Medicine, Winston-Salem, NC 27157-1032, USA
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Doobay MF, Talman LS, Obr TD, Tian X, Davisson RL, Lazartigues E. Differential expression of neuronal ACE2 in transgenic mice with overexpression of the brain renin-angiotensin system. Am J Physiol Regul Integr Comp Physiol 2006; 292:R373-81. [PMID: 16946085 PMCID: PMC1761128 DOI: 10.1152/ajpregu.00292.2006] [Citation(s) in RCA: 313] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiotensin-converting enzyme 2 (ACE2) is a newly discovered carboxy-peptidase responsible for the formation of vasodilatory peptides such as angiotensin-(1-7). We hypothesized that ACE2 is part of the brain renin-angiotensin system, and its expression is regulated by the other elements of this system. ACE2 immunostaining was performed in transgenic mouse brain sections from neuron-specific enolase-AT(1A) (overexpressing AT(1A) receptors), R(+)A(+) (overexpressing angiotensinogen and renin), and control (nontransgenic littermates) mice. Results show that ACE2 staining is widely distributed throughout the brain. Using cell-type-specific antibodies, we observed that ACE2 staining is present in the cytoplasm of neuronal cell bodies but not in glial cells. In the subfornical organ, an area lacking the blood-brain barrier and sensitive to blood-borne angiotensin II, ACE2 was significantly increased in transgenic mice. Interestingly, ACE2 mRNA and protein expression were inversely correlated in the nucleus of tractus solitarius/dorsal motor nucleus of the vagus and the ventrolateral medulla, when comparing transgenic to nontransgenic mice. These results suggest that ACE2 is localized to the cytoplasm of neuronal cells in the brain and that ACE2 levels appear highly regulated by other components of the renin-angiotensin system, confirming its involvement in this system. Moreover, ACE2 expression in brain structures involved in the control of cardiovascular function suggests that the carboxypeptidase may have a role in the central regulation of blood pressure and diseases involving the autonomic nervous system, such as hypertension.
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Affiliation(s)
- Marc F. Doobay
- Departments of Anatomy & Cell Biology The University of Iowa, Iowa City, IA
| | - Lauren S. Talman
- Departments of Anatomy & Cell Biology The University of Iowa, Iowa City, IA
| | - Teresa D. Obr
- Departments of Anatomy & Cell Biology The University of Iowa, Iowa City, IA
| | - Xin Tian
- Departments of Anatomy & Cell Biology The University of Iowa, Iowa City, IA
| | - Robin L. Davisson
- Departments of Anatomy & Cell Biology The University of Iowa, Iowa City, IA
- Departments The Cardiovascular Center, Carver College of Medicine, The University of Iowa, Iowa City, IA
| | - Eric Lazartigues
- Departments of Anatomy & Cell Biology The University of Iowa, Iowa City, IA
- Departments Pharmacology & Experimental Therapeutics Louisiana State University Health Sciences Center, New Orleans, LA, USA
- Departments Cardiovascular Center, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Marangoni RA, Carmona AK, Passaglia RCAT, Nigro D, Fortes ZB, de Carvalho MHC. Role of the kallikrein-kinin system in Ang-(1-7)-induced vasodilation in mesenteric arterioles of Wistar rats studied in vivo-in situ. Peptides 2006; 27:1770-5. [PMID: 16595159 DOI: 10.1016/j.peptides.2006.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 02/01/2006] [Accepted: 02/03/2006] [Indexed: 11/17/2022]
Abstract
Angiotensin-(1-7) [Ang-(1-7)], exerts a variety of actions in the cardiovascular system, with an important effect being vasodilation. In this work, we investigated the relationship between the vasodilatory activity of Ang-(1-7) and the kallikrein-kinin system. Intravital microscopy was used to study the vasodilation caused by Ang-(1-7) in the mesenteric vascular bed of anesthetized Wistar rats. The topical application of Ang-(1-7) caused vasodilation of mesenteric arterioles that was reduced by A-779, JE 049 and peptidase inhibitors (aprotinin, SBTI, PKSI 527, E-64, PMSF). These results indicated that the vasodilation induced by Ang-(1-7) in the mesenteric arterioles of Wistar rats was heavily dependent on the activation of kallikrein and subsequent kinin formation.
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Affiliation(s)
- Rossana Anderson Marangoni
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), Av. Prof. Lineu Prestes 1524, Cidade Universitária, 05508-900 São Paulo, SP, Brazil
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46
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Alzamora AC, Santos RAS, Campagnole-Santos MJ. Baroreflex modulation by angiotensins at the rat rostral and caudal ventrolateral medulla. Am J Physiol Regul Integr Comp Physiol 2006; 290:R1027-34. [PMID: 16306161 DOI: 10.1152/ajpregu.00852.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We determined the effect of microinjection of ANG-(1–7) and ANG II into two key regions of the medulla that control the circulation [rostral and caudal ventrolateral medulla (RVLM and CVLM, respectively)] on baroreflex control of heart rate (HR) in anesthetized rats. Reflex bradycardia and tachycardia were induced by increases and decreases in mean arterial pressure produced by intravenous phenylephrine and sodium nitroprusside, respectively. The pressor effects of ANG-(1–7) and ANG II (25 pmol) after RVLM microinjection (11 ± 0.8 and 10 ± 2 mmHg, respectively) were not accompanied by consistent changes in HR. In addition, RVLM microinjection of these angiotensin peptides did not alter the bradycardic or tachycardic component of the baroreflex. CVLM microinjections of ANG-(1–7) and ANG II produced hypotension (−11 ± 1.5 and −11 ± 1.9 mmHg, respectively) that was similarly not accompanied by significant changes in HR. However, CVLM microinjections of angiotensins induced differential changes in the baroreflex control of HR. ANG-(1–7) attenuated the baroreflex bradycardia (0.26 ± 0.06 ms/mmHg vs. 0.42 ± 0.08 ms/mmHg before treatment) and facilitated the baroreflex tachycardia (0.86 ± 0.19 ms/mmHg vs. 0.42 ± 0.10 ms/mmHg before treatment); ANG II produced the opposite effect, attenuating baroreflex tachycardia (0.09 ± 0.06 ms/mmHg vs. 0.31 ± 0.07 ms/mmHg before treatment) and facilitating the baroreflex bradycardia (0.67 ± 0.16 ms/mmHg vs. 0.41 ± 0.05 ms/mmHg before treatment). The modulatory effect of ANG II and ANG-(1–7) on baroreflex sensitivity was completely abolished by peripheral administration of methylatropine. These results suggest that ANG II and ANG-(1–7) at the CVLM produce a differential modulation of the baroreflex control of HR, probably through distinct effects on the parasympathetic drive to the heart.
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Affiliation(s)
- Andréia C Alzamora
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627-ICB, UFMG, 31270-901, Belo Horizonte, MG, Brasil
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Santos RAS, Ferreira AJ, Pinheiro SVB, Sampaio WO, Touyz R, Campagnole-Santos MJ. Angiotensin-(1-7) and its receptor as a potential targets for new cardiovascular drugs. Expert Opin Investig Drugs 2005; 14:1019-31. [PMID: 16050794 DOI: 10.1517/13543784.14.8.1019] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The identification of novel biochemical components of the renin-angiotensin system (RAS) has added a further layer of complexity to the classical concept of this cardiovascular regulatory system. It is now clear that there is a counter-regulatory arm within the RAS that is mainly formed by the angiotensin-converting enzyme 2-angiotensin (1-7)-receptor Mas axis. The functions of this axis are often opposite to those attributed to the major component of the RAS, angiotensin II. This review will highlight the current knowledge concerning the cardiovascular effects of angiotensin-(1-7) through a direct interaction with its receptor Mas or through an indirect interplay with the kallikrein-kinin system. In addition, there will be a discussion of its role in the beneficial effects of angiotensin-converting enzyme inhibitors and angio-tensin receptor type 1 (AT1) antagonists, and the potential of this peptide and its receptor as a novel targets for new cardiovascular drugs.
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Affiliation(s)
- Robson A S Santos
- Departamento de Fisiologia e Biofísica, Avenue Antônio Carlos, 6627-ICB-UFMG, 31 270-901-Belo Horizonte, MG, Brazil
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48
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Santos RAS, Ferreira AJ, Nadu AP, Braga ANG, de Almeida AP, Campagnole-Santos MJ, Baltatu O, Iliescu R, Reudelhuber TL, Bader M. Expression of an angiotensin-(1-7)-producing fusion protein produces cardioprotective effects in rats. Physiol Genomics 2004; 17:292-9. [PMID: 15039487 DOI: 10.1152/physiolgenomics.00227.2003] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiotensin-(1-7) [ANG-(1-7)] is a recently described heptapeptide product of the renin-angiotensin system. Because biosynthesis of ANG-(1-7) increases in animals treated with cardioprotective drugs and inactivation of the gene for angiotensin converting enzyme 2 [an enzyme involved in the biosynthesis of ANG-(1-7)] leads to the development of cardiac dysfunction, it has been suggested that ANG-(1-7) has cardioprotective properties. To directly test this possibility, we have generated transgenic rats that chronically overproduce ANG-(1-7) by using a novel fusion protein methodology. TGR(A1-7)3292 rats show testicular-specific expression of a cytomegalovirus promoter-driven transgene, resulting in a doubling of circulating ANG-(1-7) compared with nontransgenic control rats. Radiotelemetry hemodynamic measurements showed that transgenic rats presented a small but significant increase in daily and nocturnal heart rate and a slight but significant increase in daily and nocturnal cardiac contractility estimated by dP/d t measurements. Strikingly, TGR(A1-7)3292 rats were significantly more resistant than control animals to induction of cardiac hypertrophy by isoproterenol. In addition, transgenic rats showed a reduced duration of reperfusion arrhythmias and an improved postischemic function in isolated Langendorff heart preparations. These results support a cardioprotective role for circulating ANG-(1-7) and provide a novel tool for evaluating the functional role of ANG-(1-7).
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Affiliation(s)
- Robson A S Santos
- Laboratory of Hypertension, Department of Physiology and Biophysics, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901 Brazil.
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Veerasingham SJ, Raizada MK. Brain renin-angiotensin system dysfunction in hypertension: recent advances and perspectives. Br J Pharmacol 2003; 139:191-202. [PMID: 12770924 PMCID: PMC1573858 DOI: 10.1038/sj.bjp.0705262] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2003] [Accepted: 02/27/2003] [Indexed: 11/08/2022] Open
Abstract
This review focuses on the dysfunction of the intrinsic brain renin-angiotensin system (RAS) in the pathogenesis of hypertension. Hyperactivity of the brain RAS plays a critical role in mediating hypertension in both humans and animal models of hypertension, including the spontaneously hypertensive rat (SHR). The specific mechanisms by which increased brain RAS activity results in hypertension are not well understood but include increases in sympathetic vasomotor tone and impaired arterial baroreflex function. We discuss the contribution of endogenous angiotensin (Ang) II actions on presympathetic vasomotor rostral ventrolateral medulla neurons to enhance sympathetic activity and maintain hypertension. In addition, we discuss Ang II-induced attenuation of afferent baroreceptor feedback within the nucleus tractus solitarius and its relevance to the development of hypertension. We also outline the cellular and molecular mechanisms of Ang II signal transduction that may be critical for the initiation and establishment of hypertension. In particular, we present evidence for a phosphoinositide-3-kinase-dependent signaling pathway that appears to contribute to hypertension in the SHR, possibly via augmented Ang II-induced increases in neuronal firing rate and enhanced transcriptional noradrenaline neuromodulation. Finally, we outline future directions in utilizing our understanding of the brain RAS dysfunction in hypertension for the development of improved therapeutic intervention in hypertension.
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Affiliation(s)
| | - Mohan K Raizada
- Department of Physiology and Functional Genomics, University of Florida, U.S.A
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Neves LAA, Averill DB, Ferrario CM, Chappell MC, Aschner JL, Walkup MP, Brosnihan KB. Characterization of angiotensin-(1-7) receptor subtype in mesenteric arteries. Peptides 2003; 24:455-62. [PMID: 12732345 DOI: 10.1016/s0196-9781(03)00062-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mesenteric arteries from male Sprague-Dawley rats were mounted in a pressurized myograph system. Ang-(1-7) concentration-dependent responses were determined in arteries preconstricted with endothelin-1 (10(-7)M). The receptor(s) mediating the Ang-(1-7) evoked dilation were investigated by pretreating the mesenteric arteries with specific antagonists of Ang-(1-7), AT(1) or AT(2) receptors. The effects of Ang-(3-8) and Ang-(3-7) were also determined. Ang-(1-7) caused a concentration-dependent dilation (EC(50): 0.95 nM) that was blocked by the selective Ang-(1-7) receptor antagonist D-[Ala(7)]-Ang-(1-7). Administration of a specific antagonist to the AT(2) receptor (PD123319) had no effect. On the other hand, losartan and CV-11974 attenuated the Ang-(1-7) effect. These results demonstrate that Ang-(1-7) elicits potent dilation of mesenteric resistance vessels mediated by a D-[Ala(7)]-Ang-(1-7) sensitive site that is also sensitive to losartan and CV-11974.
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Affiliation(s)
- Liomar A A Neves
- The Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1932, USA
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