© 2000 American Heart Association, Inc.
Integrative Physiology |
Inability to Induce Hypertension in Normotensive Rat Expressing AT1 Receptor Antisense
From the Hypertension and Vascular Disease Center (C.M.F.), Wake Forest University, Winston-Salem, NC, and the Departments of Physiology (H.-W.W., C.H.G., M.K.R.) and Pharmacodynamics (A.S.P., M.J.K.), University of Florida, Colleges of Medicine and Pharmacy, Gainesville, Fla.
Correspondence to Mohan K. Raizada, PhD, Department of Physiology, College of Medicine, University of Florida, Box 100274, Gainesville, FL 32610. E-mail mraizada{at}phys.med.ufl.edu
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Abstract |
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Abstract—Our previous studies have shown that neonatal delivery of angiotensin type 1 receptor antisense (AT1R-AS) in a retroviral vector prevents spontaneously hypertensive rats from developing hypertension for life but has no effect on blood pressure (BP) in normotensive animals. Based on these results, we hypothesized that AT1R-AS transduction in normotensive rats would protect them from developing experimental hypertension. The present study was designed to evaluate this hypothesis. A single intracardiac administration of AT1R-AS by a retroviral-mediated delivery system (LNSV-AT1R-AS) in 5-day-old normotensive Sprague-Dawley rats resulted in long-term expression of the AT1R-AS without an effect on basal BP. However, angiotensin II (Ang II)–induced BP, dipsogenic responses, and renovascular contractility were significantly attenuated in the LNSV–AT1R-AS–treated rats. Chronic infusion of low-dose Ang II (55 ng · kg-1 · min-1) in LNSV-alone–treated rats caused a modest increase in BP, profound increase in cardiac hypertrophy, and increased vascular contractility. In contrast, the LNSV-AT1R-AS–treated rats were protected from developing these changes after Ang II infusion. These data establish that LNSV-AT1R-AS pretreatment protects healthy rats from developing Ang II–dependent hypertension.
Key Words: angiotensin II • gene therapy • renin-angiotensin system • angiotensin type 1 receptor • hypertension
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The renin-angiotensin system (RAS) plays an important role in human primary hypertension. Inhibition of angiotensin II (Ang II) formation or interaction with the angiotensin type 1 receptor (AT1R) is important in controlling hypertension.1 2 3 Despite great success with traditional therapy, the cure for hypertension does not seem to be forthcoming. This may be because of many inherent disadvantages with treatment approach, including compliance, side effects, and lack of complete reversal of pathophysiological aspects of the disease.4 Previously, we explored the possibilities of genetic intervention in the expression of the RAS to control hypertension and circumvent these issues. This has proven to be highly successful at the conceptual level. Our studies demonstrated that a single intracardiac injection of a retroviral vector–containing AT1R-antisense (AT1R-AS) or angiotensin-converting enzyme (ACE)–antisense cDNA prevents the development of hypertension in the spontaneously hypertensive (SH) rat on a long-term basis.4 5 6 7 8 This sustained antihypertensive effect of antisense gene therapy was not accompanied by visual side effects and was associated with long-term expression of the AT1R-AS transcript and decreased numbers of AT1R in Ang II–targeted tissues.5 During the investigation, we noticed that despite a robust and comparable expression of AT1R-AS, this strategy had no effect on the basal blood pressure (BP) of normotensive rats,4 5 6 leading us to hypothesize that the involvement of the RAS in the control of normal BP is limited. However, the contribution of the RAS is of greater significance during the development, establishment, and maintenance of hypertension. If our hypothesis is correct, we argued, then one should expect that the AT1R-AS–expressing normotensive rat would be protected from hypertension. The objective of the present study was to evaluate our hypothesis with chronic low-dose Ang II infusion in a rat model of hypertension.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Treatment of Rats With LNSV-AT1R-AS
Pregnant female Sprague-Dawley (SD) rats were obtained from the breeding colony at Wake Forest University, Winston-Salem, NC. For the AT1R-AS study, female offspring were removed from their mothers 5 days after birth and divided into 3 groups: saline control, retroviral (LNSV) vector control, and LNSV vector containing AT1R-AS cDNA (LNSV-AT1R-AS), as previously described.5 6 AT1R-AS (nucleotides –132 to +1128) was chosen because previous studies demonstrated that it blocked the functional aspects of both AT1A and AT1B receptor subtypes.9 Intracardial delivery of LNSV-AT1R-AS, saline, or LNSV (viral control) was carried out in 5-day-old rats.4 5 6 At age 10 weeks, animals were ovariectomized and fitted with ALZET 2004 minipumps (ALZET Corporation). Animals were lightly anesthetized with methoxyflurane (Metofane, Mallinckrodt Veterinary, Inc), small incisions were made in the back, minipumps filled with physiological saline or Ang II were inserted just below the skin between the shoulder blades, and the incisions were closed with wound clips. Animals were then returned to their individual cages. The pumps delivered 0.25 µL/h for 4 weeks for a final dose of Ang II of 55 ng · kg-1 · min-1.
Physiological Measurements
Indirect BPs were monitored weekly for 4 weeks with the use of
the tail-cuff method.5 6 At the end of this time period,
the effect of Ang II on dipsogenic response was determined, as
previously described.5 Water intake was expressed as
milliliters consumed per kilogram of body weight.
Direct BP measurements were carried out in cannulated rats.5 6 The animals were anesthetized with a rodent cocktail containing ketamine (100 mg/mL) and xylazine (20 mg/mL), which was administered intramuscularly (0.7 mg/kg). Jugular vein and carotid artery were catheterized for direct BP measurements in free-moving, nonrestrained animals, with a pressure transducer coupled to a Digi-Med BP analyzer (Micro-Med). After a 30-minute equilibration period, the pressor response to Ang II (0.02 to 0.32 58 g/kg IV) was determined. The effect of losartan (10 mg/kg) on BP also was examined similarly. After the Ang II pressor response, cannula flushed with 0.9% physiological saline was administered intravenously as a control. Animals were then administered losartan intravenously, and the systolic BP was determined. Contractile responses of thoracic aorta and renal arterioles to Ang II were measured, as previously described.7
Biochemical Measurements
A semiquantitative reverse transcription–polymerase chain
reaction (RT-PCR) was used to measure the levels of
AT1R-AS transcript and the
NeoR gene in various Ang II target
tissues.5 6 Total RNA was subjected to a
reverse-transcription reaction with the use of an
AT1R sense primer
(5'-CTTTCTTCTCAATCTCGCCTTGG-3'). This procedure was followed by 33
cycles of PCR using both sense and antisense primer
(5'-CCAGAAAGCCGTAGAACAGAGGG-3'). PCR products were analyzed
by polyacrylamide gel electrophoresis. The sense primer used to
detect the NeoR gene expression was
5'-CGATCTGATCAAGAGACAGGAT-3' and the antisense primer was
5'-GCCACAGTCGATGAATCCAGAA-3'.
RNAse Protection Assay
RNAse protection assay was used to detect viral
AT1R-AS mRNA by synthesizing a sense probe using
AT1R cDNA following manufacturer’s protocol
(Ambion). Genomic DNA was isolated and purified, and a PCR step was
performed for generating a template for the synthesis of the labeled
probe by adding a T7 promoter sequence to a 5' upstream primer in the
following manner: 5'-GGATCCTAATACGACTCACTATAGGGAGATGGCCCTTAA-
CTCTT; 3'-CTGGCGTAGAGGTTGAAGCTCA. This step enabled the direct
incorporation of the T7-promoter sequence into the template. This
template was used in the in vitro reaction to synthesize the mRNA with
32P-CTP in the transcription reaction containing
unlabeled 10 mmol/L ATP, 10 mmol/L UTP, 10 mmol/L GTP,
and 100 µmol/L CTP and RNA polymerase. The reaction was
incubated at 37°C for 1 hour and then treated with DNAse I. The
labeled probe was then gel purified and used within 24 hours. In the
hybridization reaction, the labeled probe (4x104
cpm) was hybridized with 30 µg of various RNAs. The RNA was
precipitated with ammonium acetate followed by ethanol. Pelleted RNA
was dissolved in hybridization buffer and incubated overnight at
42°C. The next day, the reaction was treated with 1:100 dilution of
RNAseA/RNAseT1 mix in the digestion buffer. After
centrifugation, the pellet was dissolved in the
gel-loading buffer and ran on a 5% acrylamide gel. The gel
was then exposed to film overnight at –80°C.
Statistics
All results are expressed as mean±SE. Indirect BP measurements
were analyzed by repeated-measures ANOVA. Direct mean BPs were
analyzed by ANOVA. Values of P
0.05 were considered
statistically significant. All experiments had n=7 per group, unless
otherwise indicated.
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Results |
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Characterization of AT1R-AS–Treated SD Rats
Administration of LNSV-AT1R-AS viral particles to 5-day-old SD rats resulted in the expression of AT1R-AS transcript as early as 10 days after injection.5 6 This expression was maintained in various Ang II target tissues throughout the duration of the experiment because it was apparent at 100 days after injection. Representative RT-PCR data from a 14-week-old SD rat are presented in Figure 1
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Expression of the AT1R-AS and the
NeoR gene transcript was found in the various
peripheral tissues, as shown in Figures 1A and 1B,
respectively. Expression of the AT1R-AS and
NeoR gene transcripts were also observed in
several brain areas, including the cerebrum, hypothalamus, and
brainstem (Figures 1C and 1D). These observations show that a
single intracardiac administration of
LNSV-AT1R-AS in a 5-day-old rat causes high
levels of AT1R-AS transduction in both the
periphery and the brain throughout life. RNAse protection assay was
used to confirm RT-PCR data. Figure 2
demonstrates a 
350-bp band corresponding to a protected
AT1R-AS transcript. 3T3 cells infected with the
LNSV-AT1R-AS (positive control) demonstrated a
robust expression of the transcript, whereas control cells did not show
this band.
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Despite the long-term expression of the AT1R-AS,
no significant difference was observed between basal BP in
LNSV-AT1R-AS–treated rats (105±2.0 mm Hg)
and control rats (saline or LNSV, 109±1.0 mm Hg; Figure 3A). Previous studies have implicated a
protective role of estrogens on the BP.10 11 12
Additionally, the estrous cycle influences the responsiveness to Ang
II.13 14 15 Therefore, we ovariectomized female rats to
eliminate such a protective effect and the cyclic response to Ang II.
Figure 3B shows that ovariectomy in adulthood has no effect on
basal BP in either LNSV-treated or
LNSV-AT1R-AS–treated rats. Thus, all subsequent
AT1R-AS experiments were performed in
ovariectomized rats.
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Next, we studied the physiological consequence of
AT1R-AS expression. Ang II is a potent dipsogenic
hormone, and a single subcutaneous dose of Ang II (150 µg/kg) in
LNSV-treated control rats caused an average water intake of 11±1.5
mL · kg-1 ·
h-1 (n=7) compared with an
intake of 4.5±1.5 mL ·
kg-1 ·
h-1 after administration
of saline. The drinking response to the same concentration of Ang II
was 4.4±1.5 mL ·
kg-1 ·
h-1 (n=7) in the
LNSV-AT1R-AS–treated rats, indicating a complete
attenuation of the dipsogenic response by the antisense treatment
(Figure 4). Amount of water intake was
not different from the amount observed in the same animals after saline
administration (1 µL/kg).
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Figure 5 represents the effect of
acute Ang II administration on changes in systolic BP.
Increasing doses of Ang II caused a significantly greater change in
systolic BP in LNSV-treated rats compared with
LNSV-AT1R-AS–treated rats, demonstrating the
reduced response to acute peripheral Ang II. This
difference was more pronounced at lower doses of Ang II than at higher
doses. The in vitro vascular response demonstrated a similar
attenuation to Ang II. Ang II caused a dose-dependent increase in
contraction of both thoracic aorta and renal arterioles with a similar
EC50 of 43 nmol/L in the LNSV-treated and
LNSV-AT1R-AS–treated rats (Figure 6). However, the maximal contraction was
decreased by 40% in LNSV-AT1R-AS–treated rats
(Figure 6). Specificity of the Ang II effect is shown by the
fact that KCl- or phenylephrine-induced contraction and
acetylcholine-mediated relaxation were not different between the
tissues from the LNSV-treated and
LNSV-AT1R-AS–treated rats (data not shown).
Collectively, these observations demonstrate that
AT1R-AS expression in SD rats reduced Ang
II–induced physiological responses without any
influence on basal BP. This reduced physiological
responsiveness may be associated with a decrease in the
AT1R number, which has previously been shown in
AT1R-AS–treated rats.6
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Effect of Chronic Ang II Infusion in
LNSV-AT1R-AS–Treated Rats
Because acute Ang II–induced BP and dipsogenic responses were
significantly attenuated with antisense treatment, we investigated
whether Ang II–induced hypertension would also be affected in the
LNSV-AT1R-AS–treated rat. Figure 7 shows that 55 ng ·
kg-1 ·
min-1 infusion of Ang II
caused a gradual increase in BP, which reached a maximum of 128±5
mm Hg in 4 weeks in LNSV-treated rats (Figure 7A). However, the
Ang II infusion failed to increase BP in
LNSV-AT1R-AS–treated rats, with BP similar to
that observed in the ovariectomized control without the Ang II pump. A
similar difference in the effect of Ang II was observed when direct BP
was measured; ie, BP in LNSV-AT1R-AS–treated
rats was significantly lower than in LNSV-treated rats and controls
(Figure 7B). Intravenous administration of
losartan (10 mg/kg) in chronically Ang II–treated rats caused
a 13±4 mm Hg decrease in BP in LNSV-treated rats, whereas
the same dose of losartan resulted in a 6±2 mm Hg decrease in
the BP of LNSV-AT1R-AS–treated rats (Figure 7C).
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Cardiac hypertrophy is a hallmark of hypertension. Ang
II–infused LNSV-treated rats showed a 65% increase in the ratio of
heart weight to body weight (HW/BW; Figure 8). This hypertrophy was
significantly reduced in the
LNSV-AT1R-AS–treated rats. Ang II–induced
contraction of the renal artery was increased in LNSV-treated rats
after chronic Ang II infusion. This increase was attenuated in the
LNSV-AT1R-AS–treated rats such that it was
comparable to renal artery of control rats that were not infused with
Ang II (data not shown). These observations demonstrate that, in
addition to protection from high BP, there was a significant
improvement in cardiac and renovascular responsiveness in the
AT1R-AS–treated rats.
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Discussion |
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The most significant finding of the present study is that pretreatment with antisense targeting the RAS protects normotensive rats from developing Ang II–dependent hypertension. As a result, the antisense gene therapy strategy proves useful in the treatment and prevention of hypertension. Our studies previously demonstrated that interruption in the expression of ACE or the AT1R prevents the SH rat from developing long-term hypertension.4 5 6 7 8 In addition, the antisense strategy transiently reversed hypertension in the adult SH rat once it was established.16 What is unique about the results of the present study is that targeting of the RAS by a single neonatal injection of the retroviral vector containing AT1R-AS had little or no effect on basal BP, other cardiovascular functions, or behavioral aspects in the normotensive rat despite a long-term, robust expression of the antisense transcript. However, it did protect normotensive rats from developing hypertension and associated cardiac and renovascular pathophysiology.
Ovariectomized SD female rats were used for most of this study to minimize the influence of well-studied involvement of sex steroids in BP and cardiovascular-system regulation.10 11 12 Our results demonstrate that in vivo pressor and dipsogenic and in vitro vascular responsiveness to exogenous Ang II were significantly attenuated in adult animals that were neonatally treated with single injections of AT1R-AS.
Chronic infusion of Ang II has been used as an animal model that seems
to mimic human primary hypertension. Both are characterized by a
gradual increase in BP and are associated with structural and
pathophysiological changes in various
cardiovascular-relevant organs.17
Therefore, chronic Ang II infusion represents a valuable model
to dissect the mechanisms underlying hypertension. It is well-known
that Ang II has a dose-dependent effect on BP in the Ang II infusion
model of hypertension. In our unpublished findings, we observed that a
higher dose of Ang II (150 ng ·
kg-1 ·
min-1) results in an
increase of 45 mm Hg over 4 weeks. Published studies have also
demonstrated a similar phenomenon,17 18 19 20 with infusion of
a higher dose of Ang II for a much shorter duration resulting in a
similar 45- to 60-mm Hg dose-dependent increase in BP. We decided to
use a low subpressor dose for a longer time period to allow observation
of any effects of the antisense in this model and to mimic as closely
as possible the development of Ang II–dependent human hypertension.
Ang II infusion resulted in a 20- to 30-mm Hg increase in BP from the
start of infusion in ovariectomized SD females. This increase was
prevented completely in ovariectomized SD females treated with
AT1R-AS.
Losartan and ACE inhibitors have been shown to cause regression or prevention of cardiac hypertrophy.18 In the present study, single administration of a bolus of LNSV-AT1R-AS in a 5-day-old rat resulted in a significant level of AT1R-AS expression, as measured by both RT-PCR and RNAse protection assay in various Ang II target tissues, such as heart, adrenal, kidney, and liver, an observation consistent with our previous data.5 6 The AT1R-AS expression seems to be associated with an inability of Ang II to induce high BP, an increase in HW/BW ratio, and a renovascular response to Ang II. An interesting aspect of these results is that despite modest increase in BP, low-dose Ang II infusion caused a significant increase in cardiac hypertrophy. This increase was prevented completely by LNSV-AT1R-AS treatment. It is worth pointing out that the level of hypertrophy was much more pronounced in our study than in similar studies.20 21 This may be due to the prolonged (4-week) infusion of Ang II in our study. It is also tempting to suggest that changes in BP alone could not be responsible for such a severe increase in cardiac hypertrophy, and direct hypertrophic effects of Ang II in cardiac tissue remodeling may contribute to this observation. Evidence in support of this view includes the following: (1) the degree of increase in HW/BW ratio in the chronic Ang II–infused model is similar to the degree of increase observed in the SH rat, even though the SH rat expresses considerably higher BP4 ; (2) subpressor doses of Ang II infusion cause a profound change in HW/BW ratio comparable to the change seen in the SH rat; and (3) AT1Rs are present in the cardiac tissue, and their blocking by losartan prevents hypertrophy.22 Therefore, it may be possible to separate BP effects from direct Ang II–induced effects on cardiac hypertrophy. These observations, taken together, give additional support to the notion that high BP and tissue remodeling, 2 hallmarks of hypertension, are independently controlled. The former may be a result of endocrine RAS, and the latter may be a result of regulation of the tissue RAS.17 23 24
Chronic infusion of subpressor doses of Ang II has been shown to cause an increase in AT1Rs, a phenomenon termed autopotentiation effect.25 26 As a result, there is an increased sensitivity to Ang II on BP, which may be attributable to increase in the AT1Rs.25 Our studies demonstrate that AT1R-AS treatment completely prevents the autopotentiation effect. The mechanism of autopotentiation and its resistance in the AT1R-AS–treated rats remains unelucidated, but it may be related to a decrease in the levels of AT1Rs in Ang II target tissues.
The mechanisms of hypertension caused by chronic Ang II infusion are not completely understood. The increase in BP can be mediated by a direct action on the vascular smooth muscle to increase total peripheral resistance, actions on the kidney to promote sodium retention, and resistance changes that are mediated by central effects of Ang II. Several investigators have demonstrated that hypertension induced by the use of chronic low-dose Ang II may be mediated through the CNS pathway.27 28 Although our experiments were not designed to identify the precise mechanism of Ang II–dependent hypertension, this study demonstrates for the first time that a systemic administration of AT1R-AS by a retroviral vector results in its transduction into the brain. Lack of a tight blood-brain barrier in neonatal rats may explain this observation. Expression of the AT1R-AS transcript was detected in several brain areas, including the hypothalamus, which is known to regulate Ang II–induced dipsogenic response. The dipsogenic response was significantly attenuated in the AT1R-AS–treated animals, which may be due to a decrease in central AT1R number.
In conclusion, our studies indicate that pretreatment with the LNSV-AT1R-AS protects normotensive rats from developing Ang II–induced hypertension. In addition, our data demonstrate that viral vector can transport the AT1R-AS across the poorly defined blood-brain barrier in neonates for its robust and long-term expression in the brain. Thus, these studies provide additional support to our view that antisense gene therapy that targets the RAS is a conceptually sound strategy for the prevention and possible cure of hypertension.
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Acknowledgments |
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This work was supported by grants from the National Institutes of Health (HL56912 and HL52189). A.S.P. is a predoctoral fellow of the American Heart Association Florida Affiliate.
Received September 29, 1999; accepted April 17, 2000.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
1. MacGregor GA. Blood pressure, angiotensin-converting enzyme inhibitors and the kidney. Am J Med. 1992;92:205–275.
2. Kang PM, Landau AJ, Eberhardt RJ, Frishman WH. Angiotensin II receptor antagonists: a new approach to blockade of the renin-angiotensin system. Am Heart J. 1994;127:1388–1401.[Medline] [Order article via Infotrieve]
3. van Zwieten PA. Development and trends in the drug treatment of essential hypertension. J Hypertens. 1992;10:S1–S12.
4.
Martens JR, Reaves PY, Lu D, Katovich MJ, Berecek KH,
Bishop SP, Raizada MK, Gelband CH. Prevention of renovascular and
cardiac pathophysiological changes in hypertension
by angiotensin II type 1 receptor antisense gene therapy.
Proc Natl Acad Sci U S A. 1998;95:2664–2669.
5.
Lu D, Raizada MK, Iyer S, Reaves P, Yang H, Katovich
MJ. Losartan versus gene therapy: chronic control of high blood
pressure in spontaneously hypertensive rats. Hypertension. 1997;30:363–370.
6.
Iyer SN, Lu D, Katovich MJ, Raizada MK. Chronic
control of high blood pressure in the spontaneously hypertensive rat by
delivery of angiotensin type I receptor antisense.
Proc Natl Acad Sci U S A.. 1996;93:9960–9965.
7.
Gelband CH, Reaves PY, Evans J, Wang H, Katovich MJ,
Raizada MK. Angiotensin II type 1 receptor antisense gene
therapy prevents altered renal vascular calcium homeostasis in
hypertension. Hypertension. 1999;33:360–365.
8. Wang H, Katovich MJ, Gelband CH, Reaves PY, Phillips MI, Raizada MK. Sustained inhibition of angiotensin I–converting enzyme (ACE) expression and long-term antihypertensive action by virally mediated delivery of ACE antisense cDNA. Circ Res. 1999:85;614–622.
9.
Lu D, Yu K, Raizada MK. Retrovirus-mediated transfer
of an angiotensin type I receptor
(AT1R) antisense sequence decreases
AT2Rs and angiotensin II action in
astroglial and neuronal cells in primary cultures from the brain.
Proc Natl Acad Sci U S A.. 1995;92:2914–2918.
10. Mercuro G, Zoncu S, Piano D, Pilia I, Lao A, Melis GB, Cherchi A. Estradiol-17ß reduces blood pressure and restores normal amplitude of circadian blood pressure rhythm in postmenopausal hypertension. Am J Hypertens. 1998;11:909–913.[Medline] [Order article via Infotrieve]
11. Mercuro G, Zoncu S, Pilia I, Lao A, Melis GB, Cherchi A. Effects of acute administration of transdermal estrogen on postmenopausal women with systemic hypertension. Am J Cardiol. 1997;80:652–655.[Medline] [Order article via Infotrieve]
12.
Cagnacci A, Rovati L, Zanni A, Malmussi S, Facchinetti
F, Volpe A. Physiological doses of estradiol
decrease nocturnal blood pressure in normotensive postmenopausal women.
Am J Physiol. 1999;276:H1355–H1360.
13.
Kisley LR, Sakai RR, Ma LY, Fluharty SJ.
Ovarian steroid regulation of angiotensin
II–induced water intake in the rat. Am J Physiol. 1999;276:R90–R96.
14. Ghazi N, Grove KL, Wright JW, Phillips MI, Speth RC. Variations in angiotensin-II release from the rat brain during the estrous cycle. Endocrinology. 1994;135:1945–1950.[Abstract]
15. Seltzer A, Pinto JE, Viglione PN, Correa FM, Libertun C, Tsutsumi K, Steele MK, Saavedra JM. Estrogens regulate angiotensin-converting enzyme and angiotensin receptors in female rat anterior pituitary. Neuroendocrinology. 1992;55:460–467.[Medline] [Order article via Infotrieve]
16.
Katovich MJ, Gelband CH, Reaves P, Wang HW, Raizada MK.
Reversal of hypertension by angiotensin II type 1 receptor
antisense gene therapy in the adult SHR. Am J Physiol. 1999;277:H1260–H1264.
17. Schelling P, Fischer H, Ganten D. Angiotensin and cell growth: a link to cardiovascular hypertrophy? J Hypertens. 1991;9:3–15.[Medline] [Order article via Infotrieve]
18.
Kim S, Ohta K, Hamaguchi A, Yukimura T, Miura K, Iwao
H. Angiotensin II induces cardiac phenotypic modulation and
remodeling in vivo in rats. Hypertension. 1995;25:1252–1259.
19. Lijnen P, Petrov V. Renin-angiotensin system, hypertrophy and gene expression in cardiac myocytes. J Mol Cell Cardiol. 1999;31:949–970.[Medline] [Order article via Infotrieve]
20.
Pasquie JL, Herizi A, Jover B, Mimran A. Chronic
bradykinin infusion and receptor blockade in angiotensin II
hypertension in rats. Hypertension. 1999;33:830–834.
21.
Brink M, Chrast J, Price SR, Mitch WE, Delafontaine P.
Hypertension. 1999;34:1053–1059.
22.
Li J, Touyz R, Schiffrin EL. Effects of
AT1 and AT2
angiotensin receptor antagonists in
angiotensin II–infused rats. Hypertension. 1998;31:487–492.
23. Makino N, Sugano M, Hata T, Taguchi S, Yanaga T. Chronic low-dose treatment with enalapril induced cardiac regression of left ventricular hypertrophy. Mol Cell Biochem. 1996;163–164:239–245.
24. Paul M, Stoll M, Kreutz R, Fernandez-Alfonso MS. The cellular basis of angiotensin converting enzyme mRNA expression in rat heart. Basic Res Cardiol. 1996;91(suppl 2):57–63.
25. Abraham G, Simon G. Autopotentiation of pressor responses by subpressor angiotensin II in rats. Am J Hypertens. 1994;7:269–275.[Medline] [Order article via Infotrieve]
26. Cserep G, Abraham G, Tolins JP, Simon G. Different vascular responses to subpressor angiotensin II administration in the mesenteric and renal circulation of rats. Am J Hypertens.. 1996;9:385–392.[Medline] [Order article via Infotrieve]
27. Fink GD, Haywood JR, Bryan WJ, Packwood W, Brody MJ. Central site for pressor action of blood-borne angiotensin in rats. Am J Physiol. 1980;239:R358–R361.
28.
Li Q, Dale WE, Hasser EM, Blaine EH. Acute and chronic
angiotensin hypertension: neural and nonneural components,
time course, and dose dependency. Am J Physiol. 1996;271:R200–R207.
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 S. C. FRANCIS, M. K. RAIZADA, A. A. MANGI, L. G. MELO, V. J. DZAU, P. R. VALE, J. M. ISNER, D. W. LOSORDO, J. CHAO, M. J. KATOVICH, et al. Genetic targeting for cardiovascular therapeutics: are we near the summit or just beginning the climb? Physiol Genomics, December 21, 2001; 7(2): 79 - 94. [Abstract] [Full Text] [PDF]
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