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Yokota R, Ronchi FA, Fernandes FB, Jara ZP, Rosa RM, Leite APDO, Fiorino P, Farah V, do Nascimento NRF, Fonteles MC, Casarini DE. Intra-Renal Angiotensin Levels Are Increased in High-Fructose Fed Rats in the Extracorporeal Renal Perfusion Model. Front Physiol 2018; 9:1433. [PMID: 30364140 PMCID: PMC6191567 DOI: 10.3389/fphys.2018.01433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/20/2018] [Indexed: 11/13/2022] Open
Abstract
Overconsumption of fructose leads to metabolic syndrome as a result of hypertension, insulin resistance, and hyperlipidemia. In this study, the renal function of animals submitted to high fructose intake was analyzed from weaning to adulthood using in vivo and ex vivo methods, being compared with a normal control group. We investigated in ex vivo model of the role of the renin Angiotensin system (RAS) in the kidney. The use of perfused kidney from animals submitted to 8-week fructose treatment showed that high fructose intake caused metabolic and cardiovascular alterations that were consistent with other studies. Moreover, the isolated perfused kidneys obtained from rats under high fructose diet showed a 33% increase in renal perfusion pressure throughout the experimental period due to increased renal vascular resistance and a progressive fall in the glomerular filtration rate, which reached a maximum of 64% decrease. Analysis of RAS peptides in the high fructose group showed a threefold increase in the renal concentrations of angiotensin I (Ang I) and a twofold increase in angiotensin II (Ang II) levels, whereas no change in angiotensin 1-7 (Ang 1-7) was observed when compared with the control animals. We did not detect changes in angiotensin converting enzyme (ACE) activity in renal tissues, but there is a tendency to decrease. These observations suggest that there are alternative ways of producing Ang II in this model. Chymase the enzyme responsible for Ang II formation direct from Ang I was increased in renal tissues in the fructose group, confirming the alternative pathway for the formation of this peptide. Neprilysin (NEP) the Ang 1-7 forming showed a significant decrease in activity in the fructose vs. control group, and a tendency of reduction in ACE2 activity. Thus, these results suggest that the Ang 1-7 vasodilator peptide formation is impaired in this model contributing with the increase of blood pressure. In summary, rats fed high fructose affect renal RAS, which may contribute to several deleterious effects of fructose on the kidneys and consequently an increase in blood pressure.
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Affiliation(s)
- Rodrigo Yokota
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | | | | | - Zaira Palomino Jara
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Rodolfo Mattar Rosa
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | | | - Patricia Fiorino
- Laboratory of Renal, Cardiovascular, and Metabolic Physiopharmacology, Center for Health and Biological Sciences, Mackenzie Presbyterian University, São Paulo, Brazil
| | - Vera Farah
- Laboratory of Renal, Cardiovascular, and Metabolic Physiopharmacology, Center for Health and Biological Sciences, Mackenzie Presbyterian University, São Paulo, Brazil
| | | | - Manassés C Fonteles
- Laboratory of Renal, Cardiovascular, and Metabolic Physiopharmacology, Center for Health and Biological Sciences, Mackenzie Presbyterian University, São Paulo, Brazil.,Superior Institute of Biomedical Sciences, Ceará State University, Fortaleza, Brazil
| | - Dulce Elena Casarini
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil
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Joyce T, Chirino YI, Natalia MT, Jose PC. Renal damage in the metabolic syndrome (MetSx): Disorders implicated. Eur J Pharmacol 2018; 818:554-568. [DOI: 10.1016/j.ejphar.2017.11.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 02/08/2023]
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3
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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: 83] [Impact Index Per Article: 11.9] [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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4
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Nunes ADC, Souza APS, Macedo LM, Alves PH, Pedrino GR, Colugnati DB, Mendes EP, Santos RAS, Castro CH. Influence of antihypertensive drugs on aortic and coronary effects of Ang-(1-7) in pressure-overloaded rats. ACTA ACUST UNITED AC 2017; 50:e5520. [PMID: 28355350 PMCID: PMC5423743 DOI: 10.1590/1414-431x20165520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/20/2016] [Indexed: 01/03/2023]
Abstract
This study investigated the influence of antihypertensive drugs, such as angiotensin-converting enzyme inhibitors (ACEIs), AT1 receptor blockers (ARBs), voltage-gated L-type calcium channel blockers, and mineralocorticoid receptor antagonists (MRAs), on the effects of angiotensin-(1-7) [Ang-(1-7)] on aorta and coronary arteries from pressure-overloaded rats. Pressure overload was induced by abdominal aortic banding (AB). To evaluate the role of antihypertensive drugs on the effect of Ang-(1-7), AB male Wistar rats weighing 250–300 g were treated with vehicle or low doses (5 mg·kg-1·day-1, gavage) of losartan, captopril, amlodipine, or spironolactone. Isolated aortic rings and isolated perfused hearts under constant flow were used to evaluate the effect of Ang-(1-7) in thoracic aorta and coronary arteries, respectively. Ang-(1-7) induced a significant relaxation in the aorta of sham animals, but this effect was reduced in the aortas of AB rats. Chronic treatments with losartan, captopril or amlodipine, but not with spironolactone, restored the Ang-(1-7)-induced aorta relaxation in AB rats. The coronary vasodilatation evoked by Ang-(1-7) in sham rats was blunted in hypertrophic rats. Only the treatment with losartan restored the coronary vasodilatory effect of Ang-(1-7) in AB rat hearts. These data support a beneficial vascular effect of an association of Ang-(1-7) and some antihypertensive drugs. Thus, this association may have potential as a new therapeutic strategy for cardiovascular diseases.
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Affiliation(s)
- A D C Nunes
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - A P S Souza
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - L M Macedo
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - P H Alves
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - G R Pedrino
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - D B Colugnati
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - E P Mendes
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil.,Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica, Brasil
| | - R A S Santos
- Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica, Brasil.,Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - C H Castro
- Departamento de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil.,Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica, Brasil
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5
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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6
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Sampson AK, Andrews KL, Graham D, McBride MW, Head GA, Thomas MC, Chin-Dusting JPF, Dominiczak AF, Jennings GL. Origin of the Y chromosome influences intrarenal vascular responsiveness to angiotensin I and angiotensin (1-7) in stroke-prone spontaneously hypertensive rats. Hypertension 2014; 64:1376-83. [PMID: 25201895 DOI: 10.1161/hypertensionaha.114.03756] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The lineage of the Y chromosome accounts for up to 15 to 20 mm Hg in arterial pressure. Genes located on the Y chromosome from the spontaneously hypertensive rat (SHR) are associated with the renin-angiotensin system. Given the important role of the renin-angiotensin system in the renal regulation of fluid homeostasis and arterial pressure, we hypothesized that the origin of the Y chromosome influences arterial pressure via interaction between the intrarenal vasculature and the renin-angiotensin system. Sixteen-week-old normotensive rats (Wistar Kyoto [WKY]), spontaneously hypertensive stroke-prone rat (SHRSP), and 2 reciprocal Y consomic rat strains, 1 comprising the WKY autosomes and X chromosome with the Y chromosome from the hypertensive rat strain (WKY.SPGlaY) and vice versa (SP.WKYGlaY), were examined. SP.WKYGlaY had lower systolic blood pressure than SHRSP (195±5 versus 227±8 mm Hg; P<0.03), whereas WKY.SPGlaY had higher systolic blood pressure compared with WKY (157±3 versus 148±3 mm Hg; P<0.05), measured by radiotelemetry. Compared with WKY rats, SHRSP had higher plasma angiotensin(1-7) (Ang (1-7)):Ang II ratio (WKY: 0.13±0.01 versus SHRSP: 1.33±0.4; P<0.005), greater angiotensin II receptor type 2 and Mas receptor mRNA expression, and a blunted renal constrictor response to intrarenal Ang I and Ang(1-7) infusions. Introgression of the normotensive Y chromosome into the SHRSP background (SP.WKYGlaY) restored responses in the SHRSP to WKY levels, evidenced by a reduction in plasma Ang(1-7):Ang II ratio (SP.WKYGlaY: 0.24±0.02; P<0.01), angiotensin II receptor type 2, and Mas receptor mRNA expression and an increased vasoconstrictor response to intrarenal Ang I and Ang(1-7) infusion. This study demonstrates that the origin of the Y chromosome significantly impacts the renal vascular responsiveness and therefore may influence the long-term renal regulation of blood pressure.
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Affiliation(s)
- Amanda K Sampson
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.).
| | - Karen L Andrews
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Delyth Graham
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Martin W McBride
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Geoffrey A Head
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Merlin C Thomas
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Jaye P F Chin-Dusting
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Anna F Dominiczak
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
| | - Garry L Jennings
- From the Director's Research Group (A.K.S., G.L.J.), Department of Vascular Pharmacology (A.K.S., K.L.A., J.P.F.C.-D.), Department of Neuropharmacology (G.A.H.), and Department of Diabetic Complications (M.C.T.), Baker IDI Heart and Diabetes Institute, Melbourne, Australia; and Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (D.G., M.W.M., A.F.D.)
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7
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Bi J, Contag SA, Carey LC, Tang L, Valego NK, Chappell MC, Rose JC. Antenatal betamethasone exposure alters renal responses to angiotensin-(1-7) in uninephrectomized adult male sheep. J Renin Angiotensin Aldosterone Syst 2013; 14:290-8. [PMID: 23161144 PMCID: PMC4020597 DOI: 10.1177/1470320312465217] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Antenatal corticosteroid exposure reduces renal function and alters the intrarenal renin-angiotensin system to favor angiotensin activation of angiotensin type 1 receptor (AT1R) mediated responses in ovine offspring. This study aimed to assess whether antenatal steroid exposure would affect renal responses to the direct intrarenal infusion of angiotensin-(1-7) in rams and the angiotensin receptors involved in mediating responses to the peptide. Adult, uninephrectomized rams exposed to either betamethasone or vehicle before birth received intrarenal angiotensin-(1-7) infusions (1 ng/kg/min) alone or in combination with antagonists to angiotensin receptors for 3 h. Basal sodium excretion (UNa) was significantly lower and mean arterial pressure was significantly higher in betamethasone- compared to the vehicle-treated sheep. Angiotensin-(1-7) decreased UNa more in betamethasone- than in vehicle-treated sheep. Candesartan reversed the response to angiotensin-(1-7) but D-Ala(7)-angiotensin-(1-7) did not. Angiotensin-(1-7) infusion decreased effective renal plasma flow in both groups to a similar extent and the response was reversed by candesartan, but was not blocked by D-Ala(7)-angiotensin-(1-7). Glomerular filtration rate increased significantly in both groups after 3 h infusion of angiotensin-(1-7) plus candesartan. These results suggest that antenatal exposure to a clinically relevant dose of betamethasone impairs renal function in rams. Moreover, angiotensin-(1-7) appears capable of activating the AT1R in uninephrectomized rams.
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Affiliation(s)
- Jianli Bi
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Stephen A. Contag
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Luke C. Carey
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Lijun Tang
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Nancy K. Valego
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Mark C. Chappell
- Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - James C. Rose
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
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8
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Abstract
Ang-(1-7) [angiotensin-(1-7)] is a biologically active heptapeptide component of the RAS (renin-angiotensin system), and is generated in the kidney at relatively high levels, via enzymatic pathways that include ACE2 (angiotensin-converting enzyme 2). The biological effects of Ang-(1-7) in the kidney are primarily mediated by interaction with the G-protein-coupled receptor Mas. However, other complex effects have been described that may involve receptor-receptor interactions with AT(1) (angiotensin II type 1) or AT(2) (angiotensin II type 2) receptors, as well as nuclear receptor binding. In the renal vasculature, Ang-(1-7) has vasodilatory properties and it opposes growth-stimulatory signalling in tubular epithelial cells. In several kidney diseases, including hypertensive and diabetic nephropathy, glomerulonephritis, tubulointerstitial fibrosis, pre-eclampsia and acute kidney injury, a growing body of evidence supports a role for endogenous or exogenous Ang-(1-7) as an antagonist of signalling mediated by AT(1) receptors and thereby as a protector against nephron injury. In certain experimental conditions, Ang-(1-7) appears to paradoxically exacerbate renal injury, suggesting that dose or route of administration, state of activation of the local RAS, cell-specific signalling or non-Mas receptor-mediated pathways may contribute to the deleterious responses. Although Ang-(1-7) has promise as a potential therapeutic agent in humans with kidney disease, further studies are required to delineate its signalling mechanisms in the kidney under physiological and pathophysiological conditions.
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9
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Zhuo JL, Li XC. New insights and perspectives on intrarenal renin-angiotensin system: focus on intracrine/intracellular angiotensin II. Peptides 2011; 32:1551-65. [PMID: 21699940 PMCID: PMC3137727 DOI: 10.1016/j.peptides.2011.05.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/05/2011] [Accepted: 05/09/2011] [Indexed: 02/06/2023]
Abstract
Although renin, the rate-limiting enzyme of the renin-angiotensin system (RAS), was first discovered by Robert Tigerstedt and Bergman more than a century ago, the research on the RAS still remains stronger than ever. The RAS, once considered to be an endocrine system, is now widely recognized as dual (circulating and local/tissue) or multiple hormonal systems (endocrine, paracrine and intracrine). In addition to the classical renin/angiotensin I-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II receptor (AT₁/AT₂) axis, the prorenin/(Pro)renin receptor (PRR)/MAP kinase axis, the ACE2/Ang (1-7)/Mas receptor axis, and the Ang IV/AT₄/insulin-regulated aminopeptidase (IRAP) axis have recently been discovered. Furthermore, the roles of the evolving RAS have been extended far beyond blood pressure control, aldosterone synthesis, and body fluid and electrolyte homeostasis. Indeed, novel actions and underlying signaling mechanisms for each member of the RAS in physiology and diseases are continuously uncovered. However, many challenges still remain in the RAS research field despite of more than one century's research effort. It is expected that the research on the expanded RAS will continue to play a prominent role in cardiovascular, renal and hypertension research. The purpose of this article is to review the progress recently being made in the RAS research, with special emphasis on the local RAS in the kidney and the newly discovered prorenin/PRR/MAP kinase axis, the ACE2/Ang (1-7)/Mas receptor axis, the Ang IV/AT₄/IRAP axis, and intracrine/intracellular Ang II. The improved knowledge of the expanded RAS will help us better understand how the classical renin/ACE/Ang II/AT₁ receptor axis, extracellular and/or intracellular origin, interacts with other novel RAS axes to regulate blood pressure and cardiovascular and kidney function in both physiological and diseased states.
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Affiliation(s)
- Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, the University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
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Yang R, Smolders I, Dupont AG. Blood pressure and renal hemodynamic effects of angiotensin fragments. Hypertens Res 2011; 34:674-83. [PMID: 21412242 DOI: 10.1038/hr.2011.24] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Angiotensin (Ang) II, the main effector peptide of the renin-Ang system, increases arterial blood pressure through Ang II type 1A (AT(1a)) receptor-dependent arterial vasoconstriction and by decreasing renal salt and water excretion through extrarenal and intrarenal mechanisms. AT(2) receptors are assumed to oppose these responses mediated by AT(1) receptors, thereby attenuating the pressor effects of Ang II. Nevertheless, a possible role of AT(2) receptors in the regulation of renal hemodynamics and sodium homeostasis remains to be unclear. Several other Ang fragments such as Ang III, Ang IV, Ang-(1-7) and Ang A have also been shown to display biological activity. In this review, we focus on the effects of these Ang on blood pressure, renal hemodynamics and sodium water handling, and discuss the receptors involved in these actions.
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Affiliation(s)
- Rui Yang
- Department of Pharmacology, Brussels, Belgium
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11
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Dupont AG, Yang R, Smolders I, Vanderheyden P. IRAP and AT(1) receptor mediated effects of angiotensin IV. J Intern Med 2009; 265:401-3; author reply 404-5. [PMID: 19207373 DOI: 10.1111/j.1365-2796.2008.02027.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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12
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The importance of the intrarenal renin-angiotensin system. ACTA ACUST UNITED AC 2008; 5:89-100. [PMID: 19065132 DOI: 10.1038/ncpneph1015] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 10/29/2008] [Indexed: 12/17/2022]
Abstract
Evidence suggests that virtually every organ system in the human body possesses a local renin-angiotensin system (RAS). These local systems seem to be independently regulated and compartmentalized from the plasma circulation, perhaps with the exception of the vascular endothelial system, which is responsible for maintaining physiological plasma levels of RAS components. Among these local RASs, the kidney RAS--the focus of this Review--seems to be of critical importance for the regulation of blood pressure and salt balance. Indeed, overactivation of the intrarenal RAS in certain disease states constitutes a pathogenic mechanism that leads to tissue injury, proliferation, fibrosis and ultimately, end-organ damage. Intrarenal levels of angiotensin peptides are considerably higher than those in plasma or any other organ tissue. Moreover, the kidney has a unique capacity to degrade angiotensin peptides, perhaps to maintain its intrinsic homeostasis. Interestingly, each local RAS has a distinct enzymatic profile resulting in different patterns of angiotensin fragment generation in different tissues. A better understanding of the autocrine and paracrine mechanisms involved in the renal RAS and other local RASs might direct future organ-specific therapy.
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Brain and peripheral angiotensin II type 1 receptors mediate renal vasoconstrictor and blood pressure responses to angiotensin IV in the rat. J Hypertens 2008; 26:998-1007. [DOI: 10.1097/hjh.0b013e3282f5ed58] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Effects of angiotensin II and its metabolites in the rat coronary vascular bed: is angiotensin III the preferred ligand of the angiotensin AT2 receptor? Eur J Pharmacol 2008; 588:286-93. [PMID: 18511032 DOI: 10.1016/j.ejphar.2008.04.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 03/12/2008] [Accepted: 04/17/2008] [Indexed: 01/06/2023]
Abstract
Aminopeptidases metabolize angiotensin II to angiotensin-(2-8) (=angiotensin III) and angiotensin-(3-8) (=angiotensin IV), and carboxypeptidases generate angiotensin-(1-7) from angiotensin I and II. Angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin II type 1 (AT1) receptor blockers affect the concentrations of these metabolites, and they may thus contribute to the beneficial effects of these drugs, possibly through stimulation of non-classical angiotensin AT receptors. Here, we investigated the effects of angiotensin II, angiotensin III, angiotensin IV and angiotensin-(1-7) in the rat coronary vascular bed, with or without angiotensin AT1 - or angiotensin II type 2 (AT2) receptor blockade. Results were compared to those in rat iliac arteries and abdominal aortas. Angiotensin II, angiotensin III and angiotensin IV constricted coronary arteries via angiotensin AT1 receptor stimulation, angiotensin III and angiotensin IV being approximately 20- and approximately 8000-fold less potent than angiotensin II. The angiotensin AT2 receptor antagonist PD123319 greatly enhanced the constrictor effects of angiotensin III, starting at angiotensin III concentrations in the low nanomolar range. PD123319 enhanced the angiotensin II-induced constriction at submicromolar angiotensin II concentrations only. Angiotensin-(1-7) exerted no effects in the coronary circulation, although, at micromolar concentrations, it blocked angiotensin AT1 receptor-induced constriction. Angiotensin AT2 receptor-mediated relaxation did not occur in iliac arteries and abdominal aortas, and the constrictor effects of the angiotensin metabolites in these vessels were identical to those in the coronary vascular bed. In conclusion, angiotensin AT2 receptor activation in the rat coronary vascular bed results in vasodilation, and angiotensin III rather than angiotensin II is the preferred endogenous agonist of these receptors. Angiotensin II, angiotensin III, angiotensin IV and angiotensin-(1-7) do not exert effects through non-classical angiotensin AT receptors in the rat coronary vascular bed, iliac artery or aorta.
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Wright JW, Yamamoto BJ, Harding JW. Angiotensin receptor subtype mediated physiologies and behaviors: new discoveries and clinical targets. Prog Neurobiol 2008; 84:157-81. [PMID: 18160199 PMCID: PMC2276843 DOI: 10.1016/j.pneurobio.2007.10.009] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 08/17/2007] [Accepted: 10/24/2007] [Indexed: 10/22/2022]
Abstract
The renin-angiotensin system (RAS) mediates several classic physiologies including body water and electrolyte homeostasis, blood pressure, cyclicity of reproductive hormones and sexual behaviors, and the regulation of pituitary gland hormones. These functions appear to be mediated by the angiotensin II (AngII)/AT(1) receptor subtype system. More recently, the angiotensin IV (AngIV)/AT(4) receptor subtype system has been implicated in cognitive processing, cerebroprotection, local blood flow, stress, anxiety and depression. There is accumulating evidence to suggest an inhibitory influence by AngII acting at the AT(1) subtype, and a facilitory role by AngIV acting at the AT(4) subtype, on neuronal firing rate, long-term potentiation, associative and spatial learning, and memory. This review initially describes the biochemical pathways that permit synthesis and degradation of active angiotensin peptides and three receptor subtypes (AT(1), AT(2) and AT(4)) thus far characterized. There is vigorous debate concerning the identity of the most recently discovered receptor subtype, AT(4). Descriptions of classic and novel physiologies and behaviors controlled by the RAS are presented. This review concludes with a consideration of the emerging therapeutic applications suggested by these newly discovered functions of the RAS.
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Affiliation(s)
- John W Wright
- Department of Psychology, Washington State University, P.O. Box 644820, Pullman, WA 99164-4820, USA.
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Involvement of insulin-regulated aminopeptidase in the effects of the renin–angiotensin fragment angiotensin IV: a review. Heart Fail Rev 2007; 13:321-37. [DOI: 10.1007/s10741-007-9062-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
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van Rodijnen WF, Korstjens IJ, Legerstee N, Ter Wee PM, Tangelder GJ. Direct vasoconstrictor effect of prostaglandin E2on renal interlobular arteries: role of the EP3 receptor. Am J Physiol Renal Physiol 2007; 292:F1094-101. [PMID: 17148783 DOI: 10.1152/ajprenal.00351.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Evidence indicates that prostaglandin E2(PGE2) preferentially affects preglomerular renal vessels. However, whether this is limited to small-caliber arterioles or whether larger vessels farther upstream also respond to PGE2is currently unclear. In the present study, we first investigated the effects of PGE2along the preglomerular vascular tree and subsequently focused on proximal interlobular arteries (ILAs). Proximal ILAs in hydronephrotic rat kidneys as well as isolated vessels from normal kidneys constricted in response to PGE2, both under basal conditions and after the induction of vascular tone. By contrast, smaller vessels, i.e., distal ILAs and afferent arterioles, exhibited PGE2-induced vasodilation. Endothelium removal and pretreatment of single, isolated proximal ILAs with an EP1 receptor blocker (SC51322, 1 μmol/l) or a thromboxane A2receptor blocker (SQ29548, 1 μmol/l) did not prevent vasoconstriction to PGE2. Furthermore, in the presence of SC51322, responses of these vessels to PGE2and the EP1/EP3 agonist sulprostone were superimposable, indicating that PGE2-induced vasoconstriction is mediated by EP3 receptors on smooth muscle cells. Immunohistochemical staining of proximal ILAs confirmed the presence of EP3 receptor protein on these cells and the endothelium. Adding PGE2to normal isolated kidneys induced a biphasic flow response, i.e., an initial flow increase at PGE2concentrations ≤0.1 μmol/l followed by a flow decrease at 1 μmol/l PGE2. Thus our results demonstrate that PGE2affects multiple segments of the preglomerular vascular tree in a different way. At the level of the proximal ILAs, PGE2had a direct vasoconstrictor action mediated by EP3 receptors.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Arteries/drug effects
- Arteries/physiology
- Arteries/physiopathology
- Bridged Bicyclo Compounds, Heterocyclic
- Dinoprostone/analogs & derivatives
- Dinoprostone/pharmacology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Endothelium, Vascular/physiopathology
- Fatty Acids, Unsaturated
- Hydrazines/pharmacology
- Hydronephrosis/physiopathology
- In Vitro Techniques
- Kidney Cortex/blood supply
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Muscle, Smooth, Vascular/physiopathology
- Norepinephrine/pharmacology
- Perfusion
- Rats
- Rats, Sprague-Dawley
- Receptors, Prostaglandin E/analysis
- Receptors, Prostaglandin E/antagonists & inhibitors
- Receptors, Prostaglandin E/physiology
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Renal Circulation/drug effects
- Vasoconstriction/drug effects
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- William F van Rodijnen
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
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van der Wouden EA, Ochodnický P, van Dokkum RP, Roks AJ, Deelman LE, de Zeeuw D, Henning RH. The role of angiotensin(1-7) in renal vasculature of the rat. J Hypertens 2007; 24:1971-8. [PMID: 16957556 DOI: 10.1097/01.hjh.0000244945.42169.c0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Angiotensin(1-7) is an active component of the renin-angiotensin-aldosterone system. Its exact role in renal vascular function is unclear. We therefore studied the effects of angiotensin(1-7) on the renal vasculature in vitro and in vivo. METHODS Isolated small renal arteries were studied in an arteriograph system by constructing concentration-response curves to angiotensin II, without and with angiotensin(1-7). In isolated perfused kidneys, the response of angiotensin II on renal vascular resistance was measured without and with angiotensin(1-7). The influence of angiotensin(1-7) on angiotensin II-induced glomerular afferent and efferent constriction was assessed with intravital microscopy in vivo under anaesthesia. In freely moving rats, we studied the effect of angiotensin(1-7) on angiotensin II-induced reduction of renal blood flow with an electromagnetic flow probe. RESULTS Angiotensin(1-7) alone had no effect on the renal vasculature in any of the experiments. In vitro, angiotensin(1-7) antagonized angiotensin-II-induced constriction of isolated renal arteries (9.71 +/- 1.21 and 3.20 +/- 0.57%, for control and angiotensin(1-7) pre-treated arteries, respectively; P < 0.0005). In isolated perfused kidneys, angiotensin(1-7) reduced the angiotensin II response (100 +/- 16.6 versus 72.6 +/- 15.6%, P < 0.05) and shifted the angiotensin II dose-response curve rightward (pEC50, 6.69 +/- 0.19 and 6.26 +/- 0.12 for control and angiotensin(1-7) pre-treated kidneys, respectively; P < 0.05). Angiotensin(1-7), however, was devoid of effects on angiotensin-II-induced constriction of glomerular afferent and efferent arterioles and on angiotensin-II-induced renal blood flow reduction in freely moving rats in vivo. CONCLUSION Angiotensin(1-7) antagonizes angiotensin II in renal vessels in vitro, but does not appear to have a major function in normal physiological regulation of renal vascular function in vivo.
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Affiliation(s)
- Els A van der Wouden
- Department of Clinical Pharmacology, Groningen University Institute for Drug Exploration, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Esch JHV, Danser AJ. Local Angiotensin Generation and AT2 Receptor Activation. FRONTIERS IN RESEARCH OF THE RENIN-ANGIOTENSIN SYSTEM ON HUMAN DISEASE 2007. [PMCID: PMC7119946 DOI: 10.1007/978-1-4020-6372-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Roos MH, van Rodijnen WF, van Lambalgen AA, ter Wee PM, Tangelder GJ. Renal microvascular constriction to membrane depolarization and other stimuli: pivotal role for rho-kinase. Pflugers Arch 2006; 452:471-7. [PMID: 16523358 DOI: 10.1007/s00424-006-0053-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 01/20/2006] [Accepted: 02/08/2006] [Indexed: 01/14/2023]
Abstract
Contraction of vascular smooth muscle is determined not only by levels of intracellular free calcium but also by the sensitivity of its contractile apparatus. A potential modulator of the latter is rho-kinase. We addressed the question of a possible central role for rho-kinase in the regulation of periglomerular microvascular tone. In the rat hydronephrotic kidney model, diameter changes of distal interlobular arteries, afferent and efferent arterioles were measured using three distinctly different stimuli: intravascular pressure changes, angiotensin II (AngII) and membrane depolarization, which is a physiological component of many signaling pathways, as evoked in two ways. Two selective, structurally different rho-kinase inhibitors, Y-27632 and HA-1077, were employed, as well as a selective protein kinase C alpha inhibitor. Preglomerular vasoconstriction induced by direct membrane depolarization, increases in pressure or AngII all depended for their effect on rho-kinase. A differing role for rho-kinase in efferent arteriolar constriction to AngII as compared to preglomerular microvessels was not found. In conclusion, our data indicate that in the kidney, rho-kinase is involved in a variety of signaling pathways leading to microvascular constriction. It plays a pivotal role not only in preglomerular but also in postglomerular tone.
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Affiliation(s)
- Marjon H Roos
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Van der Boechorstraat 7, 1081 BT, Amsterdam, The Netherlands
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Li XC, Campbell DJ, Ohishi M, Yuan S, Zhuo JL. AT1 receptor-activated signaling mediates angiotensin IV-induced renal cortical vasoconstriction in rats. Am J Physiol Renal Physiol 2005; 290:F1024-33. [PMID: 16380463 PMCID: PMC2276856 DOI: 10.1152/ajprenal.00221.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Angiotensin IV (ANG IV), an active ANG II fragment, has been shown to induce systemic and renal cortical effects by binding to ANG IV (AT(4)) receptors and activating unique signaling transductions unrelated to classical type 1 (AT(1)) or type 2 (AT(2)) receptors. We tested whether ANG IV exerts systemic and renal cortical effects on blood pressure, renal microvascular smooth muscle cells (VSMCs), and glomerular mesangial cells (MC) and, if so, whether AT(1) receptor-activated signaling is involved. In anesthetized rats, systemic infusion of ANG II, ANG III, or ANG IV (0.01, 0.1, and 1.0 nmol.kg(-1).min(-1) iv) caused dose-dependent increases in mean arterial pressure (MAP) and decreases in renal cortical blood flow (CBF; P < 0.01). ANG II also induced dose-dependent reductions in renal medullary blood flow (P < 0.01), whereas ANG IV did not. ANG IV-induced pressor and renal cortical vasoconstriction were completely abolished by AT(1) receptor blockade with losartan (5 mg/kg iv; P < 0.05). When ANG IV (1 nmol.kg(-1).min(-1)) was infused directly in the renal artery, CBF was reduced by >30%, and the response was also blocked by losartan (P < 0.01). In the renal cortex, unlabeled ANG IV displaced (125)I-labeled [Sar(1),Ile(8)]ANG II binding, whereas unlabeled ANG II (10 microM) inhibited (125)I-labeled Nle(1)-ANG IV (AT(4)) binding in a concentration-dependent manner (P < 0.01). In freshly isolated renal VSMCs, ANG IV (100 nM) increased intracellular Ca(2+) concentration, and the effect was blocked by losartan and U-73122, a selective inhibitor of phospholipase C/inositol trisphosphate/Ca(2+) signaling (1 microM). In cultured rat MCs, ANG IV (10 nM) induced mitogen-activated protein kinase extracellular/signal-regulated kinase 1/2 phosphorylation via AT(1) receptor- and phospholipase C-activated signaling. These results suggest that, at nanomolar concentrations, ANG IV can increase MAP and induce renal cortical effects by interacting with AT(1) receptor-activated signaling.
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Affiliation(s)
- Xiao C Li
- Laboratory of Receptor and Signal Transduction, Division of Hypertension and Vascular Research, Henry Ford Hospital, 2799 West Grand Blvd., Detroit, MI 48202, USA
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Haulica I, Bild W, Mihaila CN, Ionita T, Boisteanu CP, Neagu B. Biphasic effects of angiotensin (1-7) and its interactions with angiotensin II in rat aorta. J Renin Angiotensin Aldosterone Syst 2003; 4:124-8. [PMID: 12806596 DOI: 10.3317/jraas.2003.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Using isolated rat aortic rings perfused with Krebs-Henseleit saline, the vascular effects of angiotensin (1-7) (Ang [1-7]) and its interactions with angiotensin II (Ang II) were investigated. Ang (1-7) induced endothelium-dependent relaxation and vasodilating effects in preparations precontracted with phenylephrine. Without preconstriction, Ang (1-7) at high doses (10(-6) 10(-5) M) produced either a significant inhibition of Ang II-induced vasoconstriction or a non-tachyphylactic vasopressor response. While losartan inhibited the vasoconstriction induced by Ang (1-7), A779 blocked only its relaxation. Unlike losartan, blockade of AT(2)-receptors with PD 123319 had no effect. Taking into account the biphasic effects of angiotensin (1-7), we propose that it is one of the active components of the renin-angiotensin system, which is involved as a modulator both in the counter-regulatory actions of Ang II and in the self-regulation of its own vasodilating effects.
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Affiliation(s)
- Ion Haulica
- Labroatory of Experimental and Applied Physiology, The Romanian Academy Iasi, Iasi, Romania.
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