Abolition of long-term vascular influence of renin-angiotensin system

1990 ◽  
Vol 259 (2) ◽  
pp. H543-H553
Author(s):  
R. D. Randall ◽  
B. G. Zimmerman
Keyword(s):  
Blood Pressure ◽  
Vascular Tissue ◽  
Renin Angiotensin System ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Flow Measurements ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Normal Controls

Rabbits were bilaterally nephrectomized for 24 h or received an angiotensin-converting enzyme (ACE) inhibitor chronically (5 days) before an acute experiment. Conductance responses to sympathetic nerve stimulation (SNS) (0.25, 0.75, and 2.25 Hz) and norepinephrine (NE) administration (0.2, 0.6, and 1.8 micrograms ia) were determined from simultaneous blood pressure and iliac blood flow measurements. Conductance responses to SNS were significantly reduced in nephrectomized (44, 26, and 20%) and chronic ACE inhibition (39, 31, and 24%) groups compared with normal controls, whereas conductance responses to NE were unchanged. Continuous infusion of angiotensin II (ANG II) for 24 h restored the depressed responses to SNS in nephrectomized and chronic ACE inhibition groups compared with normal controls but did not change conductance responses to NE. Acute ACE inhibition did not affect the conductance responses to SNS or NE compared with controls. Vascular tissue ACE activity was inhibited to a similar degree (50%) in both acute and chronic ACE inhibition groups compared with normal rabbits. Sodium depletion increased the conductance responses to SNS (30 and 24% at 0.25 and 0.75 Hz, respectively), but responses to NE were not affected. Chronic ACE inhibition significantly attenuated the conductance responses to SNS and slightly decreased responses to NE in sodium-depleted rabbits. Thus, in the anesthetized rabbit, the renin-angiotensin system potentiates the effect of SNS, presumably by ANG II acting at a prejunctional site, and this effect of ANG II appears to be long term in nature. Therefore, the renin-angiotensin system exerts a physiological role in the control of blood pressure in addition to the ability of this system to support arterial pressure in pathophysiological states.

Abstract 227: The Protective Effect of Kidney-Specific ACE Inhibition Against Chronic Angiotensin II Infusions is Associated with Blunted Intrarenal Renin-Angiotensin System Activation

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Jorge F Giani ◽  
Tea Djandjoulia ◽  
Nicholas Fetcher ◽  
Sebastien Fuchs ◽  
Dale M Seth ◽  
...  
Keyword(s):  
Renin Angiotensin System ◽  
Fold Increase ◽  
Ace Inhibition ◽  
Sham Operation ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Intrarenal Ras ◽  
Failed Induction

Introduction: The responses to chronic angiotensin (Ang) II infusions of gene-targeted mice lacking kidney angiotensin-converting enzyme (ACE), in terms of intrarenal Ang II accumulation, hypertension, sodium and water retention are all blunted or absent. The objective of this study was to determine if these reduced responses were associated with changes in the intrarenal renin-angiotensin system (RAS). METHODS: Mice lacking intrarenal ACE (ACE10/10) were generated by targeted homologous recombination placing the expression of ACE only in macrophages. As a result, these mice have normal circulating ACE levels, but no kidney ACE. Wild-type (WT) mice of the same background (C57Bl/J) served as controls. Mice were subjected to sham-operation or subcutaneous infusion of Ang II for two weeks (n=6-10, 400 ng/kg/min via osmotic minipump). Mean arterial pressure (MAP) was followed by telemetry. At the end of the experiment, the kidneys were collected for analysis. Ang II content was measured by RIA. Renal abundance of ACE, angiotensinogen (AGT) and Ang II receptor type 1 (AT1R) were determined by Western Blot in total kidney homogenates. Results: At baseline, the MAP of WT and ACE 10/10 mice was similar 110 ± 4 mmHg vs. 109 ± 3 mmHg respectively (p>0.05). However, when subjected to chronic Ang II infusions, the hypertensive response was blunted in ACE 10/10 mice (129 ± 6 mmHg) vs. WT (146 ± 5 mmHg; P<0.05). Also, intrarenal Ang II accumulation was lower in ACE10/10 mice (724 ± 81 fmol/g) vs. WT (1130 ± 105 fmol/g, p<0.05). In non-treated mice, intrarenal RAS components analysis revealed that the absence of ACE in ACE10/10 mice was accompanied by a significant reduction in AGT (0.41 ± 0.06) and increased AT1R expression (1.32 ± 0.05) when compared to WT (normalized to 1.00, p<0.05 in both instances). Importantly, after chronic Ang II infusions, AGT, ACE and AT1R expression increased in WT (1.36, 1.26 and 1.17 fold increase respectively compared to non-treated WT, p<0.05) but not in the ACE10/10 mice (1.19, 1.06, 0.89 fold increase respectively compared to non-treated ACE10/10, p>0.05). Conclusion: The blunted hypertension and Ang II accumulation of mice devoid of kidney ACE in response to Ang II infusions is associated with a failed induction of renal AGT and the AT1R.

scholarly journals Involvement of the Intrarenal Renin-Angiotensin System in Experimental Models of Glomerulonephritis

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Maki Urushihara ◽  
Yukiko Kinoshita ◽  
Shuji Kondo ◽  
Shoji Kagami
Keyword(s):  
Blood Pressure ◽  
Intracellular Signaling ◽  
Renin Angiotensin System ◽  
Experimental Models ◽  
At1 Receptor ◽  
Biologically Active ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Proinflammatory Mediators

The intrarenal renin-angiotensin system (RAS) has several pathophysiologic functions not only in blood pressure regulation but also in the development of glomerulonephritis (GN). Angiotensin II (Ang II) is the biologically active product of the RAS. Locally produced Ang II induces inflammation, renal cell growth, mitogenesis, apoptosis, migration, and differentiation, regulates the gene expression of bioactive substances, and activates multiple intracellular signaling pathways, leading to tissue damage. Activation of the Ang II type 1 (AT1) receptor pathway results in the production of proinflammatory mediators, cell proliferation, and extracellular matrix synthesis, which facilitates glomerular injury. Previous studies have shown that angiotensin-converting enzyme inhibitors and/or AT1 receptor blockers have beneficial effects in experimental GN models and humans with various types of GN, and that these effects are more significant than their suppressive effects on blood pressure. In this paper, we focus on intrarenal RAS activation in the pathophysiology of experimental models of GN.

scholarly journals Role of neurons and glia in the CNS actions of the renin-angiotensin system in cardiovascular control

2015 ◽  
Vol 309 (5) ◽  
pp. R444-R458 ◽  
Author(s):  
Annette D. de Kloet ◽  
Meng Liu ◽  
Vermalí Rodríguez ◽  
Eric G. Krause ◽  
Colin Sumners
Keyword(s):  
Blood Pressure ◽  
Glial Cell ◽  
Renin Angiotensin System ◽  
Cardiovascular Control ◽  
Health Concern ◽  
Ang Ii ◽  
Ongoing Research ◽  
Angiotensin System ◽  
Renin Angiotensin

Despite tremendous research efforts, hypertension remains an epidemic health concern, leading often to the development of cardiovascular disease. It is well established that in many instances, the brain plays an important role in the onset and progression of hypertension via activation of the sympathetic nervous system. Further, the activity of the renin-angiotensin system (RAS) and of glial cell-mediated proinflammatory processes have independently been linked to this neural control and are, as a consequence, both attractive targets for the development of antihypertensive therapeutics. Although it is clear that the predominant effector peptide of the RAS, ANG II, activates its type-1 receptor on neurons to mediate some of its hypertensive actions, additional nuances of this brain RAS control of blood pressure are constantly being uncovered. One of these complexities is that the RAS is now thought to impact cardiovascular control, in part, via facilitating a glial cell-dependent proinflammatory milieu within cardiovascular control centers. Another complexity is that the newly characterized antihypertensive limbs of the RAS are now recognized to, in many cases, antagonize the prohypertensive ANG II type 1 receptor (AT1R)-mediated effects. That being said, the mechanism by which the RAS, glia, and neurons interact to regulate blood pressure is an active area of ongoing research. Here, we review the current understanding of these interactions and present a hypothetical model of how these exchanges may ultimately regulate cardiovascular function.

Differential effect of tetradecythioacetic acid on the renin-angiotensin system and blood pressure in SHR and 2-kidney, 1-clip hypertension

2007 ◽  
Vol 293 (3) ◽  
pp. F839-F845 ◽  
Author(s):  
Liliana Monica Bivol ◽  
Rolf Kristian Berge ◽  
Bjarne Magnus Iversen
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Reduction ◽  
Kidney Tissue ◽  
Renin Angiotensin System ◽  
Minor Effect ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Blood Pressure Lowering Effect ◽  
Angiotensin System ◽  
Renin Angiotensin

The tetradecythioacetic acid (TTA) is a modified fatty acid known to exhibit pleiotropic effects. First, we compared the effect of TTA on the blood pressure in spontaneously hypertensive rats (SHR) with two-kidney, one-clip (2K1C)-hypertensive rats. Second, we examined mechanisms involved in the blood pressure reduction. TTA had minor effect on systolic blood pressure (SBP) in young SHR up to 8 wk of age. In 2K1C we confirmed the blood pressure-lowering effect of TTA (SBP: 173 ± 4 before vs. 138 ± 3 mmHg after TTA, P < 0.001). No effect on SBP was seen in Wistar-Kyoto rat (WKY) controls. Plasma renin activity (PRA) was low in SHR and WKY controls and TTA did not change it. PRA decreased from 22.9 ± 1.3 to 16.2 ± 2.2 ng·ml−1·h−1 ( P = 0.02) in 2K1C. Plasma ANG II concentration declined from 101 ± 3 to 81 ± 5 fmol/l after TTA treatment ( P = 0.005). In the clipped kidney, tissue ANG I concentration decreased from 933 ± 68 to 518 ± 60 fmol/g tissue ( P = 0.001), and ANG II decreased from 527 ± 38 to 149 ± 21 fmol/g tissue ( P < 0.001) after TTA treatment. In the nonclipped kidney, TTA did not change ANG I and moderately reduced ANG II levels. The renal blood flow response to injection of ANG II into the nonclipped kidney was blunted compared with controls and normalized with TTA treatment (10 ± 2 before vs. 20 ± 2%, P < 0.001). The results indicate that TTA downregulates the renin-angiotensin system in high renin animals but has no effect in low renin models.

scholarly journals Intrarenal mouse renin-angiotensin system during ANG II-induced hypertension and ACE inhibition

2010 ◽  
Vol 298 (1) ◽  
pp. F150-F157 ◽  
Author(s):  
Romer A. Gonzalez-Villalobos ◽  
Ryousuke Satou ◽  
Naro Ohashi ◽  
Laura C. Semprun-Prieto ◽  
Akemi Katsurada ◽  
...  
Keyword(s):  
Renin Angiotensin System ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Male Mice ◽  
Rt Pcr ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Induced Hypertension ◽  
Angiotensin Type

Angiotensin-converting enzyme (ACE) inhibition (ACEi) ameliorates the development of hypertension and the intrarenal ANG II augmentation in ANG II-infused mice. To determine if these effects are associated with changes in the mouse intrarenal renin-angiotensin system, the expression of angiotensinogen (AGT), renin, ACE, angiotensin type 1 receptor (AT1R) mRNA (by quanitative RT-PCR) and protein [by Western blot (WB) and/or immunohistochemistry (IHC)] were analyzed. C57BL/6J male mice (9–12 wk old) were distributed as controls ( n = 10), ANG II infused (ANG II = 8, 400 ng·kg−1·min−1 for 12 days), ACEi only (ACEi = 10, lisinopril, 100 mg/l), and ANG II infused + ACEi (ANG II + ACEi = 11). When compared with controls (1.00), AGT protein (by WB) was increased by ANG II (1.29 ± 0.13, P < 0.05), and this was not prevented by ACEi (ACEi + ANG II, 1.31 ± 0.14, P < 0.05). ACE protein (by WB) was increased by ANG II (1.21 ± 0.08, P < 0.05), and it was reduced by ACEi alone (0.88 ± 0.07, P < 0.05) or in combination with ANG II (0.80 ± 0.07, P < 0.05). AT1R protein (by WB) was increased by ANG II (1.27 ± 0.06, P < 0.05) and ACEi (1.17 ± 0.06, P < 0.05) but not ANG II + ACEi [1.15 ± 0.06, not significant (NS)]. Tubular renin protein (semiquantified by IHC) was increased by ANG II (1.49 ± 0.23, P < 0.05) and ACEi (1.57 ± 0.15, P < 0.05), but not ANG II + ACEi (1.10 ± 0.15, NS). No significant changes were observed in AGT, ACE, or AT1R mRNA. In summary, reduced responses of intrarenal tubular renin, ACE, and the AT1R protein to the stimulatory effects of chronic ANG II infusions, in the presence of ACEi, are associated with the effects of this treatment to ameliorate augmentations in blood pressure and intrarenal ANG II content during ANG II-induced hypertension.

Pivotal role of the renin-angiotensin system in Lyon hypertensive rats

1997 ◽  
Vol 273 (5) ◽  
pp. R1793-R1799 ◽  
Author(s):  
Pierre Lantelme ◽  
Ming Lo ◽  
Laurent Luttenauer ◽  
Jean Sassard
Keyword(s):  
Renin Angiotensin System ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Adult Age ◽  
Enhanced Sensitivity ◽  
Regional Hemodynamics ◽  
Renal Vascular

We assessed the role of the renin-angiotensin system (RAS) in Lyon genetically hypertensive (LH) and normotensive (LN) rats by measuring 1) kidney renin and prorenin contents; 2) effects of early, prolonged angiotensin-converting enzyme (ACE) inhibition on blood pressure (BP) and regional hemodynamics; and 3) acute and chronic responses to angiotensin II (ANG II) and norepinephrine (NE). At the adult age, LH rats differed from LN rats by elevated BP, left ventricle weight, and vascular resistances, especially in the kidneys, associated with lower kidney renin and prorenin contents. ACE inhibition (perindopril, 3 mg ⋅ kg−1 ⋅ 24 h−1 orally from 3 to 15 wk of age) suppressed the development of hypertension, cardiac hypertrophy, and the increase in renal vascular resistances. No specific hypersensitivity to ANG II could be disclosed in acute conditions. In perindopril-treated LH rats, a 4-wk infusion of ANG II (200 ng ⋅ kg−1 ⋅ min−1) but not of NE (1,000 ng ⋅ kg−1 ⋅ min−1) restored hypertension, mimicked the hemodynamic alterations seen in untreated LH rats, and produced a brief sodium retention. It is concluded that in LH rats, despite a low basal renin secretion, hypertension and hemodynamic abnormalities 1) are fully dependent on an active RAS and 2) may involve an enhanced sensitivity to the chronic effects of ANG II.

scholarly journals From Rat to Human: Regulation of Renin-Angiotensin System Genes by Sry

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jeremy W. Prokop ◽  
Ingrid Kazue Mizuno Watanabe ◽  
Monte E. Turner ◽  
Adam C. Underwood ◽  
Almir S. Martins ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Amino Acid ◽  
Promoter Activity ◽  
Renin Angiotensin System ◽  
Pressure Variation ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Blood Pressure Variation ◽  
Testis Determination

The testis determining protein, Sry, has functions outside of testis determination. Multiple Sry loci are found on the Y-chromosome. Proteins from these loci have differential activity on promoters of renin-angiotensin system genes, possibly contributing to elevation of blood pressure. Variation at amino acid 76 accounts for the majority of differential effects by rat proteins Sry1 and Sry3. Human SRY regulated rat promoters in the same manner as rat Sry, elevatingAgt, Ren, andAcepromoter activity while downregulatingAce 2. Human SRY significantly regulated human promoters ofAGT, REN, ACE2, AT2,andMAScompared to control levels, elevatingAGTandRENpromoter activity while decreasingACE2, AT2,andMAS. While the effect of human SRY on individual genes is often modest, we show that many different genes participating in the renin-angiotensin system can be affected by SRY, apparently in coordinated fashion, to produce more Ang II and less Ang-(1–7).

Role of the renin-angiotensin system in the systemic microvascular inflammation of alveolar hypoxia

2007 ◽  
Vol 292 (5) ◽  
pp. H2285-H2294 ◽  
Author(s):  
Norberto C. Gonzalez ◽  
Julie Allen ◽  
Eric J. Schmidt ◽  
Alfred J. Casillan ◽  
Teresa Orth ◽  
...  
Keyword(s):  
Ace Inhibitor ◽  
Renin Angiotensin System ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Alveolar Hypoxia ◽  
Microvascular Inflammation

Alveolar hypoxia (AH) induces widespread systemic inflammation. Previous studies have shown dissociation between microvascular Po2 and inflammation. Furthermore, plasma from AH rats (PAHR) induces mast cell (MC) activation, inflammation, and vasoconstriction in normoxic cremasters, while plasma from normoxic rats does not produce these responses. These results suggest that inflammation of AH is triggered by a blood-carried agent. This study investigated the involvement of the renin-angiotensin system (RAS) in the inflammation of AH. Both an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II (ANG II) receptor blocker (ANG II RB) inhibited the leukocyte-endothelial adherence produced by AH, as well as the inflammation produced by PAHR in normoxic rat cremasters. MC stabilization with cromolyn blocked the effects of PAHR but not those of topical ANG II on normoxic cremasters, suggesting ANG II generation via MC activation by PAHR. This was supported by the observation that ACE inhibition and ANG II RB blocked the leukocyte-endothelial adherence produced by the MC secretagogue compound 48/80. These results suggest that the intermediary agent contained in PAHR activates MC and stimulates the RAS, leading to inflammation, and imply an RAS role in AH-induced inflammation.

scholarly journals Mediation of humoral catecholamine secretion by the renin-angiotensin system in hypotensive rainbow trout (Oncorhynchus mykiss)

1999 ◽  
Vol 160 (3) ◽  
pp. 351-363 ◽  
Author(s):  
NJ Bernier ◽  
H Kaiya ◽  
Y Takei ◽  
SF Perry
Keyword(s):  
Blood Pressure ◽  
Rainbow Trout ◽  
Enzyme Inhibitor ◽  
Plasma Concentrations ◽  
Plasma Catecholamines ◽  
Renin Angiotensin System ◽  
Adrenergic System ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin

The individual contributions of, and potential interactions between, the renin-angiotensin system (RAS) and the humoral adrenergic stress response to blood pressure regulation were examined in rainbow trout. Intravenous injection of the smooth muscle relaxant, papaverine (10 mg/kg), elicited a transient decrease in dorsal aortic blood pressure (PDA) and systemic vascular resistance (RS), and significant increases in plasma angiotensin II (Ang II) and catecholamine concentrations. Blockade of alpha-adrenoceptors before papaverine treatment prevented PDA and RS recovery, had no effect on the increase in plasma catecholamines, and resulted in greater plasma Ang II concentrations. Administration of the angiotensin-converting enzyme inhibitor, lisinopril (10(-4) mol/kg), before papaverine treatment attenuated the increases in the plasma concentrations of Ang II, adrenaline, and noradrenaline by 90, 79, and 40%, respectively and also prevented PDA and RS recovery. By itself, lisinopril treatment caused a gradual and sustained decrease in PDA and RS, and reductions in basal plasma Ang II and adrenaline concentrations. Bolus injection of a catecholamine cocktail (4 nmol/kg noradrenaline plus 40 nmol/kg adrenaline) in the lisinopril+papaverine-treated trout, to supplement their circulating catecholamine concentrations and mimic those observed in fish treated only with papaverine, resulted in a temporary recovery in PDA and RS. These results indicate that the RAS and the acute humoral adrenergic response are both recruited during an acute hypotensive stress, and have important roles in the compensatory response to hypotension in rainbow trout. However, whereas the contribution of the RAS to PDA recovery is largely indirect and relies on an Ang II-mediated secretion of catecholamines, the contribution from the adrenergic system is direct and relies at least in part on plasma catecholamines.

Role of the renin-angiotensin system in the development of thyroxine-induced hypertension

1997 ◽  
Vol 136 (6) ◽  
pp. 656-660 ◽  
Author(s):  
Cipriano Garcia del Rio ◽  
María Rosario R Moreno ◽  
Antonio Osuna ◽  
Juan de Dios Luna ◽  
Joaquín García-Estañ ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Tap Water ◽  
Weight Ratio ◽  
Renin Angiotensin System ◽  
Control Group ◽  
Angiotensin System ◽  
Renin Angiotensin

Abstract Objective: We evaluated the influence of chronic blockade of the renin-angiotensin system on hypertension induced by long-term thyroxine (T4) administration. To this end, we determined the effects of chronic treatment with captopril on blood pressure, cardiac hypertrophy and other renal and metabolic variables of hypertensive hyperthyroid rats. Methods: T4 was administered s.c. at 0·38 μmol/kg per day and captopril was given in the drinking water (1·38 mmol/l). Both treatments were maintained for 6 weeks. Control rats received tap water. After the treatment period, the rats were placed in metabolic cages. Later, blood pressure was measured in conscious rats by intra-arterial determination. Results: T4-treated rats showed an increased mean arterial pressure (MAP) whereas, in rats treated with T4 plus captopril, MAP was similar to that of the control group. Captopril did not affect the increased heart rate or ventricular weight/body weight ratio of hyperthyroid rats, but it improved the reduced creatinine clearance of these animals. Conclusions: The elevation in blood pressure produced by long-term T4 administration was prevented by chronic blockade of the renin-angiotensin system. Captopril improved the renal function of hyperthyroid rats, but did not affect the relative cardiac hypertrophy of these animals. European Journal of Endocrinology 136 656–660

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