Differential regulation of angiotensin-(1-12) in plasma and cardiac tissue in response to bilateral nephrectomy

We examined the effects of 48 h bilateral nephrectomy on plasma and cardiac tissue expression of angiotensin-(1-12) [ANG-(1-12)], ANG I, and ANG II in adult Wistar-Kyoto rats to evaluate functional changes induced by removing renal renin. The goal was to expand the evidence of ANG-(1-12) being an alternate renin-independent, angiotensin-forming substrate. Nephrectomy yielded divergent effects on circulating and cardiac angiotensins. Significant decreases in plasma ANG-(1-12), ANG I, and ANG II levels postnephrectomy accompanied increases in cardiac ANG-(1-12), ANG I, and ANG II concentrations compared with controls. Plasma ANG-(1-12) decreased 34% following nephrectomy, which accompanied 78 and 66% decreases in plasma ANG I and ANG II, respectively ( P < 0.05 vs. controls). Contrastingly, cardiac ANG-(1-12) in anephric rats averaged 276 ± 24 fmol/mg compared with 144 ± 20 fmol/mg in controls ( P < 0.005). Cardiac ANG I and ANG II values were 300 ± 15 and 62 ± 7 fmol/mg, respectively, in anephric rats compared with 172 ± 8 fmol/mg for ANG I and 42 ± 4 fmol/mg for ANG II in controls ( P < 0.001). Quantitative immunofluorescence revealed significant increases in average grayscale density for cardiac tissue angiotensinogen, ANG I, ANG II, and AT1 receptors of WKY rats postnephrectomy. Faint staining of cardiac renin, unchanged by nephrectomy, was associated with an 80% decrease in cardiac renin mRNA. These changes were accompanied by significant increases in p47phox, Rac1, and Nox4 isoform expression. In conclusion, ANG-(1-12) may be a functional precursor for angiotensin peptide formation in the absence of circulating renin.

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Localization of angiotensin peptide-forming enzymes of 3T3-F442A adipocytes

AJP Cell Physiology ◽

10.1152/ajpcell.1993.264.6.c1570 ◽

1993 ◽

Vol 264 (6) ◽

pp. C1570-C1576 ◽

Cited By ~ 49

Author(s):

J. A. Saye ◽

N. V. Ragsdale ◽

R. M. Carey ◽

M. J. Peach

Keyword(s):

Northern Blot Analysis ◽

Cell System ◽

Chain Reaction ◽

Peptide Formation ◽

Renin Mrna ◽

Sensitive Polymerase Chain Reaction ◽

The Media ◽

Angiotensin Peptide ◽

Polymerase Chain ◽

Hydrolysis Of

We have demonstrated that angiotensinogen is synthesized by 3T3-F442A cells and is hydrolyzed to angiotensins I and II (ANG I and II) by this model adipocyte system. This study was designed to determine whether ANG I is generated by renin or some other enzyme and where the formation of ANG I and/or II occurs in 3T3-F442A cells. Renin mRNA was not detected by Northern blot analysis of poly(A)(+)-selected RNA from cultures of fully differentiated adipocytes nor by the more sensitive polymerase chain reaction, implying that renin is not synthesized in this model adipocyte system. Hydrolysis of angiotensinogen to ANG I and II was demonstrated to be associated with the cell but not the media. Inhibitors, including EDTA, aimed at inactivating enzymes belonging to the serine, acid, or aspartyl proteases, and metalloproteases were ineffective in preventing the formation of either ANG I or II. Therefore the model adipocyte 3T3-F442A cell system forms ANG I and II in the absence of renin and angiotensin-converting enzyme. The unidentified enzymes responsible for peptide formation are associated with the cell itself.

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Effects of dietary salt changes on renal renin-angiotensin system in rats

AJP Renal Physiology ◽

10.1152/ajprenal.00321.2001 ◽

2002 ◽

Vol 283 (5) ◽

pp. F995-F1002 ◽

Cited By ~ 48

Author(s):

Catherine Ingert ◽

Michèle Grima ◽

Catherine Coquard ◽

Mariette Barthelmebs ◽

Jean-Louis Imbs

Keyword(s):

Renal Cortex ◽

Salt Content ◽

Renin Angiotensin System ◽

Fold Increase ◽

Kidney Cortex ◽

Ang Ii ◽

Dietary Salt ◽

High Sodium ◽

Ace Activity ◽

Wistar Kyoto

Renin (RA) and angiotensin-converting enzyme (ACE) activities and angiotensinogen, ANG I, and ANG II levels were measured in the kidney (cortex and medulla) and plasma of Wistar-Kyoto rats on a low-sodium (LS; 0.025% NaCl; n= 8), normal-sodium (NS; 1% NaCl; n = 7), or high-sodium (HS; 8% NaCl; n = 7) diet for 21 days. RA, ANG I, and ANG II levels increased in a manner inversely related to sodium content of the diet in both plasma and renal tissues. The LS diet resulted in a 16-, 2.8-, and 1.8-fold increase in plasma RA, ANG I, and ANG II levels, respectively, compared with those in HS rats. In the renal cortex and medulla, RA, ANG I, and ANG II levels were also increased by diminution of dietary salt content but, in contrast to plasma, ANG II levels increased much more than RA or ANG I levels [5.4 (cortex)- and 4.7 (medulla)-fold compared with HS rats]. In summary, we demonstrated variations of ANG II levels in the kidney during dietary salt modifications. Our results confirm that RA and ACE activity are not the steps limiting intrarenal ANG II levels. Nevertheless, despite RA and ACE activity differences between renal cortex and medulla, ANG I and ANG II levels are equivalent in these two tissues; these results argue against a compartmentalization of RAS in these two intrarenal areas.

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Vasopressin/V2 receptor stimulates renin synthesis in the collecting duct

AJP Renal Physiology ◽

10.1152/ajprenal.00360.2015 ◽

2016 ◽

Vol 310 (4) ◽

pp. F284-F293 ◽

Cited By ~ 18

Author(s):

Alexis A. Gonzalez ◽

Flavia Cifuentes-Araneda ◽

Cristobal Ibaceta-Gonzalez ◽

Alex Gonzalez-Vergara ◽

Leonardo Zamora ◽

...

Keyword(s):

Collecting Duct ◽

Critical Role ◽

Combined Treatment ◽

Receptor Activation ◽

Ang Ii ◽

Principal Cells ◽

Protein Levels ◽

Renin Synthesis ◽

Renin Mrna ◽

Creb Pathway

Renin is synthesized in the principal cells of the collecting duct (CD), and its production is increased via cAMP in angiotensin (ANG) II-dependent hypertension, despite suppression of juxtaglomerular (JG) renin. Vasopressin, one of the effector hormones of the renin-angiotensin system (RAS) via the type 2-receptor (V2R), activates the cAMP/PKA/cAMP response element-binding protein (CREB) pathway and aquaporin-2 expression in principal cells of the CD. Accordingly, we hypothesized that activation of V2R increases renin synthesis via PKA/CREB, independently of ANG II type 1 (AT1) receptor activation in CD cells. Desmopressin (DDAVP; 10−6 M), a selective V2R agonist, increased renin mRNA (∼3-fold), prorenin (∼1.5-fold), and renin (∼2-fold) in cell lysates and cell culture media in the M-1 CD cell line. Cotreatment with DDAVP+H89 (PKA inhibitor) or CREB short hairpin (sh) RNA prevented this response. H89 also blunted DDAVP-induced CREB phosphorylation and nuclear localization. In 48-h water-deprived (WD) mice, prorenin-renin protein levels were increased in the renal inner medulla (∼1.4- and 1.8-fold). In WD mice treated with an ACE inhibitor plus AT1 receptor blockade, renin mRNA and prorenin protein levels were still higher than controls, while renin protein content was not changed. In M-1 cells, ANG II or DDAVP increased prorenin-renin protein levels; however, there were no further increases by combined treatment. These results indicate that in the CD the activation of the V2R stimulates renin synthesis via the PKA/CREB pathway independently of RAS, suggesting a critical role for vasopressin in the regulation of renin in the CD.

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An Energetic Approach to Modeling Cytoskeletal Architecture in Maturing Cardiomyocytes

Journal of Biomechanical Engineering ◽

10.1115/1.4052112 ◽

2021 ◽

Author(s):

William F Sherman ◽

Mira Asad ◽

Anna Grosberg

Keyword(s):

Cardiac Tissue ◽

Length Scales ◽

Functional Changes ◽

Physical Constraints ◽

Scale Parameters ◽

Structure And Dynamics ◽

Energetic Approach ◽

Cytoskeletal Network ◽

Multiple Length Scales ◽

Potential Factors

Abstract Through a variety of mechanisms, a healthy heart is able to regulate its structure and dynamics across multiple length scales. Disruption of these mechanisms can have a cascad- ing effect, resulting in severe structural and/or functional changes that permeate across different length scales. Due to this hierarchical structure, there is interest in understand- ing how the components at the various scales coordinate and influence each other. However, much is unknown regarding how myofibril bundles are organized within a densely packed cell and the influence of the subcellular components on the architecture that is formed. To elucidate potential factors influencing cytoskeletal development, we proposed a compu- tational model that integrated interactions at both the cel- lular and subcelluar scale to predict the location of indi- vidual myofibril bundles that contributed to the formation of an energetically favorable cytoskeletal network. Our model was tested and validated using experimental metrics derived from analyzing single cell cardiomyocytes. We demonstrated that our model-generated networks were capable of repro- ducing the variation observed in experimental cells at different length scales as a result of the stochasticity inher- ent in the different interaction between the various cellu- lar components. Additionally, we showed that incorporat- ing length-scale parameters resulted in physical constraints that directed cytoskeletal architecture towards a structurally consistent motif. Understanding the mechanisms guiding the formation and organization of the cytoskeleton in individual cardiomyocytes can aid tissue engineers towards developing functional cardiac tissue.

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Abstract 261: Endothelial Cells Contribute to RAS Activation in Microvascular Smooth Muscle Cells

Circulation Research ◽

10.1161/res.111.suppl_1.a261 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Kayoko Miyata ◽

Ryousuke Satou ◽

L Gabriel Navar

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Mrna Expression ◽

Culture Medium ◽

Primary Cultures ◽

Mrna Levels ◽

Ang Ii ◽

Relative Ratio ◽

Renin Mrna ◽

Afferent Arterioles

Introduction: We have demonstrated that Ang II augments angiotensinogen (AGT) expression in rat preglomerular vascular smooth muscle cells (VSMCs). However, it is unclear if endothelial cells (ECs) are involved in augmentation of AGT in renal afferent arterioles. Hypothesis: We assessed the hypothesis that the ECs respond to paracrine signals that Ang II contribute to AGT augmentation in VSMCs. Objective: We established primary cultures of preglomerular ECs and examined the effects of Ang II and/or culture medium from ECs on AGT expression in preglomerular VSMCs. Methods and Results: We established primary cultures of preglomerular ECs, isolated from afferent arterioles of Sprague-Dawley rats. The cells were identified as ECs by being positive for a marker, CD34 and endothelial NOS and negative for alpha-SMA (a marker for VSMCs) and P4H-b (a marker for Fibroblasts) by immnostaining. The expression levels of AGT mRNA and renin mRNA in preglomerular ECs were examined by real-time RT-PCR. Ang II (100 pmol/L) increased AGT mRNA levels (1.34 +/- 0.16, by 100 pmol/L, N=4) and Renin mRNA levels (6.16 +/- 0.96, by 100 nmol/L, N=4) in ECs. On the other hand, the same dose of Ang II suppressed Renin mRNA expression in isolated Juxtaglomerular cells (JGs). These results indicate that preglomerular ECs are respond to Ang II and exclude the possible contamination of JGs into ECs. 100 pmol/L of Ang II increased AGT mRNA expression levels (1.37 +/- 0.03, relative ratio, N=4) in preglomerular VSMCs and the culture medium of ECs without Ang II treatment also more increased AGT mRNA expression (1.62 +/- 0.13, relative ratio, N=4) in preglomerular VSMCs. The AGT mRNA expression augmentation was enhanced when preglomerular VSMCs were treated with culture medium of Ang II-treated preglomerular ECs (2.39 +/- 0.41, relative ratio, N=4). The synergistic effects of Ang II and preglomerular ECs were also observed in PAI-1 expression in preglomerular VSMCs. Conclusion: These data demonstrate that preglomerular ECs contribute to Ang II-upregulation of AGT in renal afferent arterioles leading to further Ang II augmentation, which leads to increases in inflammatory and sclerotic factors in preglomerular VSMCs.

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ACE inhibitors and cardiac ACE mRNA in volume overload-induced cardiac hypertrophy

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.273.2.h641 ◽

1997 ◽

Vol 273 (2) ◽

pp. H641-H646 ◽

Cited By ~ 6

Author(s):

W. Lear ◽

M. Ruzicka ◽

F. H. Leenen

Keyword(s):

Cardiac Hypertrophy ◽

Ace Inhibitors ◽

Cardiac Tissue ◽

Ace Inhibitor ◽

Internal Standard ◽

Phosphoglycerate Kinase ◽

Volume Overload ◽

Ang Ii ◽

Aortocaval Shunt

Quinapril, an angiotensin-converting enzyme (ACE) inhibitor with high affinity for cardiac ACE, prevents increases in both plasma and cardiac angiotensin II (ANG II) and development of cardiac hypertrophy after aortocaval shunt in rats. In contrast, enalapril, an ACE inhibitor with low affinity for cardiac ACE, only prevents the increase in plasma ANG II. In the present study, we assessed whether these differences between enalapril and quinapril reflect different inhibition of cardiac tissue ACE and local ANG II by measuring their effects on cardiac ACE mRNA. Treatment with enalapril (250 mg/l) and quinapril (200 mg/l in drinking water) was started 3 days before the shunt and sham surgery. After 1 wk of aortocaval shunt, the hearts were excised and the left ventricle and right ventricle were weighed and used for reverse transcriptase-polymerase chain reaction (RT-PCR) assays for ACE and phosphoglycerate kinase-1 (internal standard). Quinapril, but not enalapril, inhibited the development of cardiac hypertrophy by aortocaval shunt. The shunt increased ACE mRNA in both left and right ventricles about twofold. In animals with aortocaval shunt, quinapril markedly further upregulated ACE mRNA in both ventricles, whereas enalapril did not cause significant changes. In sham rats, both ACE inhibitors increased ACE mRNA, but the increase was more pronounced by treatment with quinapril. These studies show that in vivo ACE inhibitors with low (enalapril) vs. high (quinapril) affinity for cardiac ACE differ in their effects on cardiac ACE mRNA. This difference is more pronounced in volume overload-induced cardiac hypertrophy, presumably reflecting their different effects on cardiac ANG II.

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Renal cytochrome P-450-arachidonic acid metabolism: localization and hormonal regulation in SHR

AJP Renal Physiology ◽

10.1152/ajprenal.1992.262.4.f591 ◽

1992 ◽

Vol 262 (4) ◽

pp. F591-F599 ◽

Cited By ~ 29

Author(s):

K. Omata ◽

N. G. Abraham ◽

M. L. Schwartzman

Keyword(s):

Hormonal Regulation ◽

Distribution Patterns ◽

Arachidonic Acid Metabolism ◽

Proximal Tubules ◽

Ang Ii ◽

Spontaneously Hypertensive ◽

Nephron Segments ◽

Wistar Kyoto ◽

Cytochrome P 450 ◽

Stimulation Of

Epoxygenase and omega- and omega-1-hydroxylases are the major cytochrome P-450-arachidonate (P-450-AA) metabolizing enzymes in renal tissues. We measured P-450-AA metabolism in single nephron segments and determined the tubular localization of this activity in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Formation of 20-hydroxyeicosatetraenoic acid (20-HETE), the product of AA omega-hydroxylase was specifically localized in the entire proximal tubules (S1, S2, and S3 segments), whereas formation of 19-HETE, the product of omega-1-hydroxylase and epoxyeicosatrienoic acids (EETs), products of AA epoxygenase, was demonstrable throughout the tubule. Although distribution patterns were similar in SHR and WKY, formation of 19- and 20-HETE in the proximal tubules was higher in SHR, whereas the formation of EETs was not different between the two strains. In the proximal tubules, angiotensin II (ANG II) significantly stimulated epoxygenase activity (EETs formation), whereas parathyroid hormone (PTH) and epidermal growth factor (EGF) had no effect on epoxygenase but significantly stimulated omega-hydroxylase activity (20-HETE formation). Because P-450-AA metabolites have a wide and contrasting spectrum of biological and renal effects, from vasodilation to vasoconstriction and from inhibition to stimulation of Na(+)-K(+)-adenosinetriphosphatase, their localization to the specific nephron segments and differential stimulation of their formation by ANG II, PTH, and EGF may contribute not only to renal hemodynamics and blood pressure regulation but also to the regulation of renal sodium and water balance.

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Localization of the novel angiotensin peptide, angiotensin-(1-12), in heart and kidney of hypertensive and normotensive rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.91521.2007 ◽

2008 ◽

Vol 294 (6) ◽

pp. H2614-H2618 ◽

Cited By ~ 57

Author(s):

Jewell A. Jessup ◽

Aaron J. Trask ◽

Mark C. Chappell ◽

Sayaka Nagata ◽

Johji Kato ◽

...

Keyword(s):

Ventricular Myocytes ◽

Renal Tubules ◽

Uptake Mechanism ◽

Spontaneously Hypertensive ◽

Wky Rats ◽

Angiotensin Peptide ◽

Wistar Kyoto ◽

Renal Tubular ◽

Alternate Substrate ◽

First Time

A low expression of angiotensinogen in the heart has been construed as indicating a circulating uptake mechanism to explain the local effects of angiotensin II on tissues. The recent identification of angiotensin-(1-12) in an array of rat organs suggests this propeptide may be an alternate substrate for local angiotensin production. To test this hypothesis, tissues from 11-wk-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats ( n = 14) were stained with purified antibodies directed to the COOH terminus of angiotensin-(1-12). Robust angiotensin-(1-12) staining was predominantly found in ventricular myocytes with less staining found in the medial layer of intracoronary arteries and vascular endothelium. In addition, angiotensin-(1-12) immunoreactivity was present in the proximal, distal, and collecting renal tubules within the deep cortical and outer medullary zones in both strains. Preadsorption of the antibody with angiotensin-(1-12) abolished staining in both tissues. Corresponding tissue measurements by radioimmunoassay showed 47% higher levels of angiotensin-(1-12) in the heart of SHR compared with WKY rats ( P < 0.05). In contrast, renal angiotensin-(1-12) levels were 16.5% lower in SHR compared with the WKY rats ( P < 0.05). This study shows for first time the localization of angiotensin-(1-12) in both cardiac myocytes and renal tubular components of WKY and SHR. In addition, we show that increased cardiac angiotensin-(1-12) concentrations in SHR is associated with a small, but statistically significant, reduction in renal angiotensin-(1-12) levels.

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CCN2 (Cellular Communication Network Factor 2) Deletion Alters Vascular Integrity and Function Predisposing to Aneurysm Formation

Hypertension ◽

10.1161/hypertensionaha.121.18201 ◽

2021 ◽

Author(s):

R. Rodrigues-Díez Raul ◽

Antonio Tejera-Muñoz ◽

Vanesa Esteban ◽

B. Steffensen Lasse ◽

Raquel Rodrigues-Díez ◽

...

Keyword(s):

Communication Network ◽

Rapid Development ◽

Cellular Communication ◽

Aortic Aneurysms ◽

Matricellular Protein ◽

Ang Ii ◽

Mineralocorticoid Receptor Antagonist ◽

Functional Changes ◽

Aneurysm Formation ◽

Cellular Communication Network

Background: CCN2 (cellular communication network factor 2) is a matricellular protein involved in cell communication and microenvironmental signaling responses. CCN2 is known to be overexpressed in several cardiovascular diseases, but its role is not completely understood. Methods: Here, CCN2 involvement in aortic wall homeostasis and response to vascular injury was investigated in inducible Ccn2 -deficient mice, with induction of vascular damage by infusion of Ang II (angiotensin II; 15 days), which is known to upregulate CCN2 expression in the aorta. Results: Ang II infusion in CCN2-silenced mice lead to 60% mortality within 10 days due to rapid development and rupture of aortic aneurysms, as evidenced by magnetic resonance imaging, echography, and histological examination. Ccn2 deletion decreased systolic blood pressure and caused aortic structural and functional changes, including elastin layer disruption, smooth muscle cell alterations, augmented distensibility, and increased metalloproteinase activity, which were aggravated by Ang II administration. Gene ontology analysis of RNA sequencing data identified aldosterone biosynthesis as one of the most enriched terms in CCN2-deficient aortas. Consistently, treatment with the mineralocorticoid receptor antagonist spironolactone before and during Ang II infusion reduced aneurysm formation and mortality, underscoring the importance of the aldosterone pathway in Ang II–induced aorta pathology. Conclusions: CCN2 is critically involved in the functional and structural homeostasis of the aorta and in maintenance of its integrity under Ang II–induced stress, at least, in part, by disruption of the aldosterone pathway. Thus, this study opens new avenues to future studies in disorders associated to vascular pathologies.

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Abstract P152: Aminopeptidase A in the Brain Exerts Cardiovascular Action via Degradation of Kallidin to Bradykinin

Hypertension ◽

10.1161/hyp.68.suppl_1.p152 ◽

2016 ◽

Vol 68 (suppl_1) ◽

Author(s):

Takuto Nakamura ◽

Masanobu Yamazato ◽

Yusuke Ohya

Keyword(s):

Blood Pressure ◽

Pressor Response ◽

Cardiovascular Regulation ◽

Receptor Blocker ◽

Ang Ii ◽

Aminopeptidase A ◽

Hoe 140 ◽

Wistar Kyoto ◽

The Brain

Objective: Aminopeptidase A (APA) degrades of various sympathomodulatory peptides such as angiotensin (Ang) II, cholecystkinin-8, neurokinin B and kallidin. APA activity is increased in the brain of hypertensive rats. A centrally acting APA inhibitor prodrug is currently under investigation in clinical trial for treatment of hypertension. In previous reports, a role of APA in the brain on cardiovascular regulation was researched focus on only renin-angiotensin system. We previously reported that intracerebroventricular(icv) administration of APA increased blood pressure and that this pressor response was partially blocked by angiotensin receptor blocker. In this study, we evaluated a role of APA on cardiovascular regulation focusing on peptides other than Ang II. Method: Eleven weeks old Wistar Kyoto rats were used. We icv administrated 800 ng/8 μL of APA after pretreatment of following drugs, i) 8μL of artificial cerebrospinal fluid (aCSF) as a control, ii) 80 nmol/8 μL of amastatin which is a non-specific aminopeptidase inhibitor, iii) 1 nmol/8 μL of HOE-140 which is a bradykinin receptor blocker to evaluate the involvement of degradation of kallidin to bradykinin by APA. Result: i) Icv administration of APA after pretreatment of aCSF increased blood pressure rapidly. Blood pressure reached a peak within 1 minute. The elevated blood pressure decreased gradually and reached baseline blood pressure in 10 minutes. A peak pressor response is 25.5±1.4 mmHg (n=5). ii) Icv pretreatment of amastatin or HOE-140 did not change the blood pressure. A peak pressor response induced by APA is 13.1±4.1 mmHg (n=6, p<0.05 vs aCSF). iii) Icv pretreatment of HOE-140 did not change the blood pressure. A peak pressor response induced by APA is 21.2±1.8 mmHg (n=4, p<0.05 vs aCSF). Conclusion: 1) Icv administration of APA increased blood pressure by APA enzymatic activity. 2) Cardiovascular regulation of APA in the brain is due to not only degradation of Ang II to Ang III but also degradation of kallidin to bradykinin. Clinical implication: We think inhibition of APA in the brain may be a unique therapeutic target which affects several cardiovascular peptides in the brain.

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