This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by d’Uscio, L. V. Articles by Lüscher, T. F. Search for Related Content PubMed PubMed Citation Articles by d’Uscio, L. V. Articles by Lüscher, T. F. Related Collections Endothelium/vascular type/nitric oxide Hypertension - basic studies

(Hypertension. 2001;37:28.)
© 2001 American Heart Association, Inc.

Scientific Contributions

Vasopeptidase Inhibition Prevents Endothelial Dysfunction of Resistance Arteries in Salt-Sensitive Hypertension in Comparison With Single ACE Inhibition

Presented in part at the 53rd annual Fall Conference and Scientific Session of the Council for High Blood Pressure Research, Orlando, Fla.

Livius V. d’Uscio; Thomas Quaschning; John C. Burnett, Jr; Thomas F. Lüscher

From the Cardiovascular Research, Institute of Physiology, University Zürich, and Division of Cardiology, University Hospital (L.V.d’U., T.Q., T.F.L.), Zürich, Switzerland; and Cardiorenal Research Laboratory (J.C.B.), Mayo Clinic and Foundation, Rochester, Minn.

Correspondence to Thomas F. Lüscher, MD, FRCP, FACC, FESC, Cardiology, University Hospital Zürich, CH-8091 Zürich, Switzerland. E-mail cardiotfl{at}compuserve.com

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Abstract—To determine whether natriuretic peptides in addition to the renin-angiotensin system are involved in functional and structural vascular changes in salt-sensitive hypertension, we compared equipotent hypotensive treatment with the dual neutral endopeptidase/ACE inhibitor omapatrilat (35 mg · kg^-1 · d^-1) or the ACE inhibitor captopril (100 mg · kg^-1 · d^-1). The reactivity and geometry of mesenteric resistance arteries from Dahl salt-sensitive rats were studied in vitro under perfused and pressurized conditions. Chronic salt administration increased systolic blood pressure by 57±4 mm Hg, whereas concentrations of atrial natriuretic peptide were reduced in heart and in plasma (P<0.05). In addition, the medial cross-sectional area of small mesenteric arteries was increased and endothelium-dependent relaxation in response to acetylcholine and contraction in response to endothelin-1 were impaired in the mesenteric arteries of salt-sensitive rats on a high-salt diet (P<0.05). Concomitant treatment with either omapatrilat or captopril reduced the increase in systolic blood pressure and hypertrophic remodeling to a similar degree (P<0.05) but affected plasma and cardiac atrial natriuretic peptide levels differently (P<0.05). In addition, omapatrilat normalized endothelium-dependent relaxations to a greater extent than captopril (P<0.05). Furthermore, vasopeptidase inhibition increased cGMP levels compared with captopril (P<0.05). Contractions to endothelin-1 were normalized by either antihypertensive drug. These results suggest that in the Dahl rat, with similar reductions in systolic blood pressure, omapatrilat is superior to captopril in preventing impaired endothelial function in small resistance arteries. Thus, vasopeptidase inhibition may have therapeutic advantages of the prevention of changes in vascular function and structure in salt-sensitive forms of hypertension.

Key Words: resistance • arteries • nitric oxide • atrial natriuretic peptide • vasopeptidase • angiotensin-converting enzyme • rats, Dahl

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Natriuretic peptides and endothelium-derived vasoactive factors are important regulators of the cardiovascular system.^{1 2} The vascular endothelium is a source of vasoactive substances such as NO,³ as well as endothelin-1 (ET-1)⁴ and angiotensin,^{5 6} that modulate vascular smooth muscle cell (VSMC) tone and proliferation. NO is a potent vasodilator and is formed from L-arginine by endothelial NO synthase.⁷ Vasodilation in response to abluminal release of endothelium-derived NO is associated with an increase in cGMP in VSMCs.⁸

The natriuretic peptide family consists of 3 peptides: atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP).² ANP is a potent natriuretic and vasoactive peptide that is produced predominantly in the atrial myocytes; BNP is mainly produced by the left ventricle of the heart.^{9 10} Both peptides are released into the circulation and thus play an important role as autocrine mediators in the control of cardiorenal homeostasis and of vascular tone.¹¹ In contrast, CNP is of endothelial origin and plays a paracrine role in the regulation of vascular tone and structure.^{12 13 14} Natriuretic peptides are degraded by neutral endopeptidase (NEP), which is widely distributed in endothelial cells, VSMCs, cardiac myocytes, and renal epithelial cells.¹⁵

In human essential hypertension, excessive salt intake has been suggested as one of the contributing factors for the development of hypertension, in particular if associated with renal insufficiency.^{16 17} Dahl salt-sensitive (DS) rats with salt-induced hypertension exhibit vascular hypertrophy of mesenteric arteries¹⁸ and have reduced endothelium-dependent responses in the aorta¹⁹ and small mesenteric arteries.²⁰ Recently, it was shown that a dual NEP/ACE inhibitor is more effective as an antihypertensive in low-, normal-, and high-renin models of hypertension than those elicited through selective inhibition of either enzyme alone.^{21 22} However, the contribution of natriuretic peptides, in addition to that of the renin-angiotensin system, to functional and structural vascular alterations in salt-induced hypertension is not known. Therefore, we investigated the effects of chronic NEP/ACE inhibition with omapatrilat compared with single ACE inhibition captopril on salt-induced hypertension with a special emphasis on endothelium-dependent and -independent vascular reactivity and the vascular structure of small resistance arteries.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Animals
Male DS rats at 5 to 6 weeks of age were obtained from Charles River WIGA GmbH and held at the animal facilities of Institute of Physiology, University of Zürich, up to 4 weeks. Housing facilities and all experimental protocols were approved by the local authorities for animal research in Zürich, Switzerland. Rats were distributed in random order into 1 of 4 groups: (1) a control group (control; fed standard chow that contained 0.3% NaCl and water ad libitum), (2) a salt-treated group (salt; fed chow that contained 4% salt [special rat diet from Harlan]), (3) a salt-plus-omapatrilat group (salt 4% plus omapatrilat; 35 mg · kg^-1 · d^-1 omapatrilat), and (4) a salt-plus-captopril group (salt 4% plus captopril; 100 mg · kg^-1 · d^-1 captopril). The drugs were mixed with salted or normal powdered chow, and total chow intake was monitored every day. The dosages of omapatrilat and captopril were based on previous studies.^{21 22 23 24} Systolic arterial pressure and heart rate were measured according to the tail-cuff method with a pulse transducer (model LE 5000; Letica), and body weight of the rats was monitored before and after 2, 4, and 8 weeks of treatment.

Tissue Harvesting
The rats were anesthetized (thiopental 50 mg/kg body wt IP) and killed. A segment of a fourth branch of mesenteric artery (closest to ileum) was isolated and dissected free under a microscope (Leica Wild M3C) in cold (4°C) modified Krebs-Ringer bicarbonate solution composed of (in mmol/L) NaCl 118.6, KCl 4.8, CaCl₂ 2.5, MgSO₄ 1.2, KH₂PO₄ 1.2, NaHCO₃ 25.1, Ca²⁺-EDTA 0.026, and glucose 10.1.

Experimental Setup
Isolated mesenteric arteries were transferred to small vessel chambers (Living Systems Instrumentation), filled with Krebs-Ringer bicarbonate solution. The solutions circulating from a 250-mL reservoir at a flow rate of 50 mL/min were aerated continuously with 95% O₂ and 5% CO₂ gas and kept at 37°C. Proximal and distal ends of the small vessels were mounted and sutured onto 2 small glass microcannulas (inflow and outflow cannula, respectively) positioned in the vessel chamber. The axial length of the vessel was carefully adjusted longitudinally under a microscope by positioning the afferent cannula. The perfusion pressure was set at a level that has been previously shown to be optimal for contractions to norepinephrine (30 mm Hg).²⁰ The perfusion chamber was positioned on the stage of an inverted microscope (TSM-F; Nikon) with a video camera. The amplified image was transmitted to a monitor and a video dimension analyzer (V91; Living Systems Instrumentation) to allow measurements and recording of the lumen diameter and media thickness.

Protocols
Mesenteric arteries were equilibrated for 60 minutes and perfused intraluminally with Krebs’ solution containing 1% BSA. Between each protocol, the system was washed with Krebs’ solution and then equilibrated for 30 minutes. Concentration-response curve to norepinephrine (10^-9 to 3x10^-5 mol/L) were first obtained. Endothelium-dependent relaxations to acetylcholine (10^-9 to 3x10^-5 mol/L) after preincubation with or without N-nitro-L-arginine methyl ester (L-NAME; 10^-4 mol/L) alone for 30 minutes or in combination with indomethacin (10^-5 mol/L) for 20 minutes were obtained after stabilization of half-maximal contraction to norepinephrine. Finally, a concentration-response curve to ET-1 (10^-11 to 10^-7 mol/L) was constructed.

Drugs
The following drugs were used for in vitro experiments and were administered extraluminally in the circulating Krebs’ buffer solution: acetylcholine hydrochloride, L-norepinephrine bitartrate, L-NAME, and indomethacin (all from Sigma Chemical Co) and ET-1 (Novabiochem AG). Omapatrilat and captopril were from Bristol-Myers Squibb.

Measurement of Plasma and Heart Concentrations of Natriuretic Peptides
Blood samples were obtained through puncture of the right ventricle. The blood was immediately transferred to a tube that contained EDTA and centrifuged at 4°C for 10 minutes. Plasma was separated immediately at 4°C and kept at -80°C until assayed. Rat heart was placed in 4°C Krebs’ solution, the blood was rinsed out, and the heart was kept at -80°C. Plasma and heart ANP, BNP, and CNP immunoreactivities were determined with a double-antibody radioimmunoassay as previously described.^{11 25 26} Protein assay was conducted with a DC Protein assay kit (BioRad).

Measurements of cGMP and cAMP
First- to fourth-order branches of the mesenteric arterial tree were dissected free from surrounding tissue 4°C in Krebs’ solution and were kept at -80°C until assayed. Tissue was minced in a grinding tube (Duall 20; Kontes Glass Co) and suspended in 25 mmol/L Tris buffer, pH 7.4, as described previously.²⁷ cGMP and cAMP radioimmunoassay kits (Amersham) were used to perform the measurements, and total protein was determined with the BioRad kit. The results are expressed as pmol/mg protein.

Data Analysis
For statistical analysis, sensitivity of the vessels to different drugs was expressed as negative logarithm of the concentration that caused half-maximal relaxation or contraction (pD₂ value). In addition, maximal contraction or relaxation (expressed as percentage of the decrease in the basal intraluminal diameter or of the increase in intraluminal diameter from the diameter obtained after precontraction, respectively) was determined for each concentration-response curve through nonlinear regression analysis with MatLab software. Arterial cross-sectional area and remodeling index were calculated as described elsewhere.²⁸ All results are given as mean±SEM. In all experiments, n indicates the number of rats. Single values were compared by 1-way ANOVA with Bonferroni’s correction for multiple comparisons.²⁹ The concentration-response curves of the different groups were compared by ANOVA for repeated measurements, with Bonferroni’s correction to compare the different groups. Where appropriate, a paired or unpaired t test was used. A value of P<0.05 was considered significant.

	Results

Top Abstract Introduction Methods Results Discussion References

 
Systolic Blood Pressure, Heart Rate, and Body Weight
Systolic blood pressure was increased by chronic salt administration in DS rats compared with control baseline (P<0.05, n=7, Figure 1A, Table 1). Concomitant treatment with omapatrilat or captopril prevented part of the salt-induced pressure rise (P<0.05 versus salt DS, n=6 or 7, Figure 1). The heart rate did not change during treatment with different regimens (Table 1). Before treatment, the mean body weight did not differ between groups. After 8 weeks, the body weight increased in all groups. However, in the salt-fed DS group, the weight gain was less (P<0.05 versus control, Table 1) and was normalized by either omapatrilat or captopril (P<0.05 versus salt group).

View larger version (23K): [in this window] [in a new window]   Figure 1. Systolic blood pressure changes after 8 weeks of treatment in Dahl salt-sensitive rats. Results are shown as mean±SEM (n=6 or 7). *P<0.05 vs control. P<0.05 vs salt-treated group (ANOVA plus Bonferroni’s).

View this table: [in this window] [in a new window]   Table 1. Characteristics of the Dahl Rats Before and During the Treatment Period

Levels of Natriuretic Peptides in Plasma and Heart
After chronic salt treatment, the plasma levels of ANP were markedly decreased (P<0.05, Figure 2A). After concomitant treatment with omapatrilat, concentrations of the peptide were increased (P<0.05 versus salt group). However, captopril further decreased ANP (P<0.05 versus salt-plus-omapatrilat group, Figure 2A). Plasma BNP and CNP levels were unchanged (Figure 2A).

View larger version (39K): [in this window] [in a new window]   Figure 2. Plasma levels of ANP, BNP, and CNP (A) and concentrations of ANP and BNP in the heart (B) of Dahl salt-sensitive rats with salt-induced hypertension. Results are shown as mean±SEM (n=5 to 7 per group). *P<0.05 vs control. P<0.05 vs salt-treated group. #P<0.05 vs salt-plus-omapatrilat (Omap) group (ANOVA plus Bonferroni’s). Capt indicates captopril.

Cardiac ANP and BNP levels were reduced in DS rats on the high-salt diet (P<0.05, Figure 2B). Omapatrilat and captopril normalized BNP levels compared with the salt group (P<0.05), whereas only captopril increased tissue ANP levels in the heart (P<0.05 versus salt-plus-omapatrilat group, Figure 2B).

Vascular Structure
In small mesenteric arteries, chronic salt administration increased media thickness and media-to-lumen ratio (P<0.05 compared with control, Table 2). These changes were accompanied by a decrease in lumen diameter and an increase in cross-sectional area of the media due to hypertrophic remodeling (P<0.05 versus control, Table 2). However, the alteration of vascular geometry was also in part accompanied by a rearrangement of vascular tissue around a smaller lumen (calculated remodeling index 54%). Both omapatrilat and captopril normalized medial thickness and media-to-lumen ratio to similar degrees (P<0.05 versus salt group, Table 2). The external diameter was unchanged (Table 2).

View this table: [in this window] [in a new window]   Table 2. Morphological Characteristics of Small Arteries From Dahl Rats Measured Under Perfused and Pressurized Conditions

Endothelium-Dependent Relaxations
In small mesenteric arteries from salt-sensitive rats, endothelium-dependent relaxations to acetylcholine were impaired by the high-salt diet (P<0.05, Figure 3A). Both omapatrilat and captopril significantly improved responses to acetylcholine (P<0.05 versus salt-treated group for maximal relaxation). However, maximal relaxations in the captopril group were still impaired (P<0.05 versus salt-plus-omapatrilat group, n=6 or 7, Figure 3A). Preincubation of L-NAME shifted the relaxation response curve 10-fold to the right in all groups of treated rats, but maximal relaxations were not different in either group (data not shown; n=5 or 6). Indomethacin had no additional effect on acetylcholine-induced relaxations (data not shown, n=4).

View larger version (26K): [in this window] [in a new window]   Figure 3. Endothelium-dependent relaxation in response to acetylcholine (A) and tissue cGMP (B) levels in small mesenteric arteries of Dahl salt-sensitive rats with salt-induced hypertension. Results are shown as mean±SEM (n=6 or 7 per group), and relaxations are expressed as percent of the increase in intraluminal diameter from precontraction with norepinephrine. *P<0.05 vs control. P<0.05 vs salt-treated group. #P<0.05 vs salt-plus-omapatrilat group (ANOVA plus Bonferroni’s).

Tissue cGMP and cAMP Levels
Basal cGMP level was slightly increased in mesenteric arteries from the salt-treated group compared with control (P<0.05, Figure 3B). Concomitant treatment with omapatrilat, but not captopril, further increased cGMP concentrations (P<0.05 versus salt-plus-captopril group). In contrast, basal cAMP levels did not differ among control (4.9±0.6 pmol/mg), the salt group (5.6±1.0 pmol/mg), the salt-plus-omapatrilat group (6.3±1.1 pmol/mg), and the salt-plus-captopril group (6.1±0.5 pmol/mg).

Vascular Contractions
The contractions to norepinephrine and ET-1 were reduced in mesenteric arteries of salt-treated DS (P<0.05 versus control DS, Figure 3A). This attenuation was normalized in salt-treated DS rats receiving either omapatrilat or captopril (P<0.05, n=6 or 7, Figure 4).

View larger version (24K): [in this window] [in a new window]   Figure 4. Concentration-dependent contractions to norepinephrine (A) and ET-1 (B) in mesenteric arteries of Dahl rats with salt-induced hypertension. Results are shown as mean±SEM (n=6 or 7 per group), and contractions are expressed as percent of decrease in basal intraluminal diameter. *P<0.05 vs control. P<0.05 vs salt-treated group (ANOVA plus Bonferroni’s).

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
The present study shows that dual ACE/NEP inhibition with omapatrilat normalized impaired endothelium-dependent relaxations to acetylcholine in the microcirculation to a greater extent than with equipotent antihypertensive treatment with the ACE inhibitor captopril in DS rats on the high-salt diet. In addition, omapatrilat, but not captopril, increased cGMP levels in small mesenteric arteries. On the other hand, both omapatrilat and captopril normalized vascular structure and contractions to norepinephrine and ET-1, but they affected on reduced plasma ANP and heart ANP and BNP concentrations differently in salt-sensitive hypertension.

Vasopeptidase inhibition is a new concept in cardiovascular therapy.³⁰ It involves simultaneous inhibition with a single molecule of 2 key enzymes, NEP and ACE, which are both involved in the regulation of cardiovascular homeostasis. It has been shown that omapatrilat exhibits greater antihypertensive effects than those elicited by the selective inhibition of either enzyme alone.^{21 22} However, in the present study, we simultaneously compared omapatrilat and captopril regarding endothelium-dependent relaxations and vascular structure. To exclude a contribution of hemodynamic effects, equally antihypertensive dosages of both drugs were selected.

In DS rats, hypertension is associated with a reduction in body weight gain after long-term treatment with a high-salt diet.¹⁹ The inadequate weight gain may be due to reduced appetite, renal failure, or both. Indeed, it was shown that a profound glomerular injury is present in hypertensive DS rats.^{23 31} As a consequence of progressive renal failure, increased natriuresis occurs, which may contribute to the body weight loss. Moreover, plasma ANP levels, which in DS rats are markedly higher than those of other natriuretic peptides, were decreased in salt-induced hypertension. Hence, ANP may be unable to regulate body fluid to reduce cardiac preload and afterload in this form of hypertension. Accordingly, ANP and BNP production of cardiac origin was also reduced. Interestingly, in salt-sensitive black patients with essential hypertension, plasma concentrations of ANP are also reduced in response to a high-salt diet.³² In addition, in deoxycorticosterone acetate-salt hypertensive rats, gene expression of renal ANP mRNA is blunted.³³ In our study, concomitant treatment with omapatrilat, but not captopril, increased plasma levels of ANP, whereas opposite effects of the antihypertensive drugs on tissue ANP were found in the heart. The exact mechanisms of these differential effects remain to be determined.

Consistent with previous reports, the present study showed that the salt diet impaired endothelium-dependent relaxation in response to acetylcholine in mesenteric arteries.²⁰ Because the response to acetylcholine was decreased by the NO inhibitor L-NAME, impaired endothelial production of NO or reduced bioavailability of NO, or both, must be involved in the blunted endothelium-dependent relaxations in hypertensive DS rats.^{34 35} Boegehold et al³⁶ demonstrated that NO-mediated relaxation was also impaired in the arterioles of salt-resistant rats on a high-salt diet, indicating that salt per se may in part have an effect on vasodilator responses independent of an elevation in blood pressure. However, this observation contrasts with results obtained by our group.²⁰ Furthermore, a direct effect of salt, if present, would not affect the results and conclusions reached in the present study, because both groups (those receiving omapatrilat or captopril) were exposed to the same salt diet.

Omapatrilat and captopril prevented morphological alterations in mesenteric arteries of hypertensive DS rats to a similar degree. Interestingly, treatment with the dual NEP/ACE inhibitor normalized endothelium-dependent relaxations to a greater extent than equipotent hypotensive dosages of the ACE inhibitor captopril, although systolic blood pressure was only in part reduced by both drugs as previously reported with other agents.^{20 37} The mechanism of these differential effects of omapatrilat and captopril is not entirely clear. However, because ACE and NEP are involved in the metabolism of several peptides, such as natriuretic peptides, bradykinin, substance P, angiotensin, and ET,^{15 38 39} clearance of the peptides from the circulation may play an important role,⁴⁰ and thus, the remaining peptides may be determinants of these vascular protective effects. In addition, differences in plasma ANP levels in the omapatrilat and captopril groups may contribute to the improvement of endothelium-dependent relaxations. Accordingly, a recent study showed that ANP enhances NOS activity and NO production, suggesting that the NO pathway may be a second messenger for ANP.⁴¹

The observed altered vascular responses could be related not only to a reduced production of NO but also to an altered responsiveness of VSMCs to NO due to an impaired activation of second messengers such as cGMP.⁸ However, we found that basal cGMP levels were slightly increased in mesenteric arteries of DS rats on a high-salt diet, demonstrating that impaired endothelial function is not related to the altered VSMC reactivity to NO. Interestingly, omapatrilat, but not captopril, further increased cGMP production, which may reflect the normalization of endothelial function. Indeed, natriuretic peptides have been shown to stimulate cGMP production in cultured endothelial cells and VSMCs,^{42 43} again suggesting that the increase in ANP by omapatrilat may be relevant for impaired endothelial function. The failure of captopril to normalize relaxations to acetylcholine may also be due to suppression of the renin-angiotensin system in this rat model of hypertension.^{17 44}

ET-1–induced contractions were reduced in mesenteric arteries of DS rats on a high-salt diet as previously reported.²⁰ This may be due to the receptor downregulation and/or alteration in signal transduction pathways. Interestingly, chronic inhibition with either omapatrilat or captopril improved the responses to the peptides to a comparable degree, suggesting that the effects of omapatrilat are unlikely to involve the ET system in this model.

In conclusion, the present results demonstrate that long-term salt treatment in DS rats with equihypotensive dosages of omapatrilat and captopril significantly affects endothelium-dependent relaxations and tissue cGMP levels in small mesenteric arteries differently. Thus, chronic combined NEP/ACE inhibition with omapatrilat may represent an interesting alternative not only to lower systolic blood pressure but also, in particular, to improve vascular function and structure, and in turn clinical outcome, in salt-dependent forms of hypertension.

	Acknowledgments

 
This study was supported by the Swiss National Foundation (grant 32-51069.97 to Dr Lüscher), National Institutes of Health (grant HL-36634 to Dr Burnett), and Bristol-Myers Squibb (Princeton, NJ). Dr d’Uscio is a recipient of a stipend from the ADUMED Foundation and Novartis Foundation. The Deutscher Akademischer Austauschdienst (DAAD) supported Dr Quaschning. Dr Jim Powell (Bristol-Myers Squibb) kindly supplied omapatrilat and captopril and helped to design the protocol. The authors thank Denise Heublein for the measurement of natriuretic peptides and Dr Christian Binggeli for his excellent support in software programming.

Received December 20, 2000; first decision January 6, 2000; accepted July 28, 2000.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Lüscher TF, Vanhoutte PM. The Endothelium: Modulator of Cardiovascular Function. Boca Raton, Fla: CRC Press; 1990.
2. Levin ER, Gardner DG, Samson WK. Natriuretic peptides. N Engl J Med. 1998;339:321–328.[Free Full Text]
3. Palmer RMJ, Ferrige AG, Moncada S. Nitric oxide release accounts for the biological activity of endothelium-derived relaxing factor. Nature. 1987;327:524–526.[Medline] [Order article via Infotrieve]
4. Yanagisawa M, Kurihara H, Kimura S, Tomobe Y, Kobayashi M, Mitsui Y, Yazaki Y, Goto K, Masaki T. A novel potent vasoconstrictor peptide produced by vascular endothelial cells. Nature. 1988;332:411–415.[Medline] [Order article via Infotrieve]
5. Lee MA, Böhm M, Paul M, Ganten D. Tissue renin-angiotensin systems: their role in cardiovascular disease. Circulation. 1993;87:IV7-IV13.
6. Dzau VJ. Local expression and pathophysiological role of renin-angiotensin in the blood vessels and heart. In: Grobecker H, Heusch G, Strauer BE, eds. Angiotensin and the Heart. Darmstadt, Germany: Steinkopff Verlag; 1993:1–14.
7. Palmer RMJ, Ashton DS, Moncada S. Vascular endothelial cells synthesize nitric oxide from L-arginine. Nature. 1988;333:664–666.[Medline] [Order article via Infotrieve]
8. Rapoport RM, Draznin MB, Murad F. Endothelium-dependent relaxation in rat aorta may be mediated through cyclic GMP-dependent protein phosphorylation. Nature. 1983;306:174–176.[Medline] [Order article via Infotrieve]
9. de Bold AJ. Atrial natriuretic factor: a hormone produced by the heart. Science. 1985;230:767–770.[Abstract/Free Full Text]
10. La Villa G, Bisi G, Lazzeri C, Fronzaroli C, Stefani L, Barletta G, Del Bene R, Messeri G, Strazzulla G, Franchi F. Cardiovascular effects of brain natriuretic peptide in essential hypertension. Hypertension. 1995;25:1053–1057.[Abstract/Free Full Text]
11. Burnett JC, Jr, Kao PC, Hu DC, Heser DW, Heublein D, Granger JP, Opgenorth TJ, Reeder GS. Atrial natriuretic peptide elevation in congestive heart failure in the human. Science. 1986;231:1145–1147.[Abstract/Free Full Text]
12. Wei CM, Kim CH, Khraibi AA, Miller VM, Burnett JC Jr. Atrial natriuretic peptide and C-type natriuretic peptide in spontaneously hypertensive rats and their vasorelaxing actions in vitro. Hypertension. 1994;23:903–907.[Abstract/Free Full Text]
13. Clavell AL, Stingo AJ, Wei CM, Heublein DM, Burnett JCJ. C-type natriuretic peptide: a selective cardiovascular peptide. Am J Physiol. 1993;264:R290–R295.[Abstract/Free Full Text]
14. Nazario B, Hu RM, Pedram A, Prins B, Levin ER. Atrial and brain natriuretic peptides stimulate the production and secretion of C-type natriuretic peptide from bovine aortic endothelial cells. J Clin Invest. 1995;95:1151–1157.
15. Erdos EG, Skidgel RA. Neutral endopeptidase 24.11 (enkephalinase) and related regulators of peptide hormones. FASEB J. 1989;3:145–151.[Abstract]
16. Dahl LK, Heine M, Tassinair L. Effects of chronic excess salt ingestion: evidence that genetic factors play an important role in susceptibility to experimental hypertension. J Exp Med. 1962;115:1173–1190.[Abstract]
17. Rapp JP. Dahl salt-susceptible and salt-resistant rats. Hypertension. 1982;4:753–763.[Free Full Text]
18. Lee RMKW, Triggle CR. Morphometric study of mesenteric arteries from genetically hypertensive Dahl strain rats. Blood Vessels. 1986;23:199–224.[Medline] [Order article via Infotrieve]
19. Lüscher TF, Raij L, Vanhoutte PM. Endothelium-derived vascular responses in normotensive and hypertensive Dahl rats. Hypertension. 1987;9:157–163.[Abstract/Free Full Text]
20. d’Uscio LV, Barton M, Shaw S, Moreau P, Lüscher TF. Structure and function of small arteries in salt-induced hypertension: effects of chronic endothelin-subtype-A receptor blockade. Hypertension. 1997;30:905–911.[Abstract/Free Full Text]
21. Trippodo NC, Robl JA, Asaad MM, Fox M, Panchal BC, Schaeffer TR. Effects of omapatrilat in low, normal, and high renin experimental hypertension. Am J Hypertens. 1998;11:363–372.[Medline] [Order article via Infotrieve]
22. Tikkanen T, Tikkanen I, Rockell MD, Allen TJ, Johnston CI, Cooper ME, Burrell LM. Dual inhibition of neutral endopeptidase and angiotensin-converting enzyme in rats with hypertension and diabetes mellitus. Hypertension. 1998;32:778–785.[Abstract/Free Full Text]
23. Tolins JP, Raij L. Comparison of converting enzyme inhibitor and calcium channel blocker in hypertensive glomerular injury. Hypertension. 1990;16:452–461.[Abstract/Free Full Text]
24. Wang DH, Prewitt RL. Longitudinal effect of captopril on aortic and arteriolar development in normotensive rats. Am J Physiol. 1991;260:H1959–H1965.[Abstract/Free Full Text]
25. Clavell AL, Stingo AJ, Aarhus LL, Burnett JC Jr. Biological actions of brain natriuretic peptide in thoracic inferior vena caval constriction. Am J Physiol. 1993;265:R1416–R1422.[Abstract/Free Full Text]
26. Stingo AJ, Clavell AL, Heublein DM, Wei CM, Pittelkow MR, Burnett JC Jr. Presence of C-type natriuretic peptide in cultured human endothelial cells and plasma. Am J Physiol. 1992;263:H1318–H1321.[Abstract/Free Full Text]
27. Grantham JA, Borgeson DD, Burnett JC Jr. BNP: pathophysiological and potential therapeutic roles in acute congestive heart failure. Am J Physiol. 1997;272:R1077–R1083.[Abstract/Free Full Text]
28. Heagerty AM, Aalkjær C, Bund SJ, Korsgaard N, Mulvany MJ. Small artery structure in hypertension: dual processes of remodeling and growth. Hypertension. 1993;21:391–397.[Free Full Text]
29. Wallenstein S, Zucker CL, Fleiss J. Some statistical methods useful in Circulation Research. Circ Res. 1980;47:1–9.[Abstract/Free Full Text]
30. Burnett JC Jr. Vasopeptidase inhibition: a new concept in blood pressure management. J Hypertens Suppl. 1999;17:S37–S43.
31. Raij L, Azar S, Keane W. Mesangial immune injury, hypertension, and progressive glomerular damage in Dahl rats. Kidney Int. 1984;26:137–143.[Medline] [Order article via Infotrieve]
32. Campese VM, Tawadrous M, Bigazzi R, Bianchi S, Mann AS, Oparil S, Raij L. Salt intake and plasma atrial natriuretic peptide and nitric oxide in hypertension. Hypertension. 1996;28:335–340.[Abstract/Free Full Text]
33. Ogawa T, Linz W, Scholkens BA, de Bold AJ. Variable renal atrial natriuretic factor gene expression in hypertension. Hypertension. 1999;33:1342–1347.[Abstract/Free Full Text]
34. Hayakawa H, Raij L. The link among nitric oxide synthase activity, endothelial function, and aortic and ventricular hypertrophy in hypertension. Hypertension. 1997;29:235–241.[Abstract/Free Full Text]
35. Swei A, Lacy F, DeLano FA, Schmid-Schonbein GW. Oxidative stress in the Dahl hypertensive rat. Hypertension. 1997;30:1628–1633.[Abstract/Free Full Text]
36. Boegehold MA. Effect of dietary salt on arteriolar nitric oxide in striated muscle of normotensive rats. Am J Physiol. 1993;264:H1810–H1816.[Abstract/Free Full Text]
37. Dohi Y, Criscione L, Pfeiffer K, Lüscher TF. Angiotensin blockade or calcium antagonists improve endothelial dysfunction in hypertension: studies in perfused mesenteric resistance arteries. J Cardiovasc Pharmacol. 1994;24:372–379.[Medline] [Order article via Infotrieve]
38. Stephenson SL, Kenny AJ. Metabolism of neuropeptides: hydrolysis of the angiotensins, bradykinin, substance P and oxytocin by pig kidney microvillar membranes. Biochem J. 1987;241:237–247.[Medline] [Order article via Infotrieve]
39. Roques BP. Cell surface metallopeptidases involved in blood pressure regulation: structure, inhibition and clinical perspectives. Pathol Biol (Paris). 1998;46:191–200.[Medline] [Order article via Infotrieve]
40. Asaad MM, Dorso CR, Moreland SM. Effects of neutral endopeptidase inhibition on the clearance of exogenously administered endothelin in Sprague-Dawley rats. J Cardiovasc Pharmacol. 1993;21:633–636.[Medline] [Order article via Infotrieve]
41. Costa M, Bosc LV, Majowicz MP, Vidal NA, Balaszczuk AM, Arranz CT. Atrial natriuretic peptide modifies arterial blood pressure through nitric oxide pathway in rats. Hypertension. 2000;35:1119–1123.[Abstract/Free Full Text]
42. Porter JG, Catalano R, McEnroe G, Lewicki JA, Protter AA. C-type natriuretic peptide inhibits growth factor-dependent DNA synthesis in smooth muscle cells. Am J Physiol. 1992;263:C1001–C1006.[Abstract/Free Full Text]
43. Marumo T, Nakaki T, Hishikawa K, Hirahashi J, Suzuki H, Kato R, Saruta T. Natriuretic peptide-augmented induction of nitric oxide synthase through cyclic guanosine 3',5'-monophosphate elevation in vascular smooth muscle cells. Endocrinology. 1995;136:2135–2142.[Abstract]
44. Rapp JP, McPartland RP, Sustarsic DL. A qualitative difference in plasma renin activity in Dahl rats susceptible or resistant to salt induced hypertension. Biochem Genet. 1980;18:1087–1096.[Medline] [Order article via Infotrieve]

This article has been cited by other articles:

				F. Vargas, J. M. Moreno, R. Wangensteen, I. Rodriguez-Gomez, and J. Garcia-Estan The endocrine system in chronic nitric oxide deficiency Eur. J. Endocrinol., January 1, 2007; 156(1): 1 - 12. [Abstract] [Full Text] [PDF]

				R. S Garcha and A. D Hughes CNP, but not ANP or BNP, Relax Human Isolated Subcutaneous Resistance Arteries by an Action Involving Cyclic GMP and BKCa Channels Journal of Renin-Angiotensin-Aldosterone System, June 1, 2006; 7(2): 87 - 91. [Abstract] [PDF]

				J. Varagic, D. Susic, M. Slama, and E. D. Frohlich Omapatrilat Induces Profound Renal Vasodilation but Does Not Affect Coronary Hemodynamics Journal of Cardiovascular Pharmacology and Therapeutics, June 1, 2003; 8(2): 167 - 174. [Abstract] [PDF]

				A. A. Elmarakby, P. Morsing, and D. M. Pollock Regulation of Cardiovascular Signaling by Kinins and Products of Similar Converting-Enzyme Systems: Enalapril attenuates endothelin-1-induced hypertension via increased kinin survival Am J Physiol Heart Circ Physiol, June 1, 2003; 284(6): H1899 - H1903. [Abstract] [Full Text] [PDF]

				M. Azizi, M. Lamarre-Cliche, A. Labatide-Alanore, A. Bissery, T. T. Guyene, and J. Menard Physiologic Consequences of Vasopeptidase Inhibition in Humans: Effect of Sodium Intake J. Am. Soc. Nephrol., October 1, 2002; 13(10): 2454 - 2463. [Abstract] [Full Text] [PDF]

				R. Corti, J. C. Burnett Jr, J. L. Rouleau, F. Ruschitzka, and T. F. Luscher Vasopeptidase Inhibitors: A New Therapeutic Concept in Cardiovascular Disease? Circulation, October 9, 2001; 104(15): 1856 - 1862. [Abstract] [Full Text] [PDF]

				T. Quaschning, L. V. d'Uscio, S. Shaw, H. Viswambharan, F. T. Ruschitzka, and T. F. Luscher Chronic vasopeptidase inhibition restores endothelin-converting enzyme activity and normalizes endothelin levels in salt-induced hypertension Nephrol. Dial. Transplant., June 1, 2001; 16(6): 1176 - 1182. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by d’Uscio, L. V. Articles by Lüscher, T. F. Search for Related Content PubMed PubMed Citation Articles by d’Uscio, L. V. Articles by Lüscher, T. F. Related Collections Endothelium/vascular type/nitric oxide Hypertension - basic studies