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Herin Laetitia - - 2003
Rats of the Fischer 344 (F344) and Wistar Kyoto (WKY) strains are known to present differences in stimuli responses involving the renin-angiotensin system and in cardiovascular responses to an acoustic startle stimulus. Here we compared the vascular reactivity to angiotensin II (ANG II) of these normotensive, inbred rat strains. Blood ...
Danser A H Jan - - 2003
The concept of local renin-angiotensin systems has been introduced almost 20 years ago to explain the beneficial blood pressure-independent effects of ACE inhibitors and AT(1) receptor antagonists in cardiovascular diseases. In the past decade, research has focussed on the local effects of angiotensin II rather than on the mechanism(s) of ...
Engeli Stefan - - 2003
Overfeeding of rodents leads to increased local formation of angiotensin II due to increased secretion of angiotensinogen from adipocytes. Whereas angiotensin II promotes adipocyte growth and preadipocyte recruitment, increased secretion of angiotensinogen from adipocytes also directly contributes to the close relationship between adipose-tissue mass and blood pressure in mice. In ...
Slivkoff Mark D - - 2003
This study was undertaken to test the hypothesis that, in toads, the pressor effects of angiotensin II (ANG II) are partly due to the secondary effects of catecholamines. In Bufo marinus, blood pressure responses to bullfrog ([Val(5)]) ANG II administration were measured in animals pretreated (experimental group) and not pretreated ...
Barrett Carolyn J - - 2003
Increasing evidence suggests elevated sympathetic outflow may be important in the genesis of hypertension. It is thought that peripheral angiotensin II, in addition to its pressor actions, may act centrally to increase sympathetic nerve activity (SNA). Without direct long-term recordings of SNA, testing the involvement of neural mechanisms in angiotensin ...
Matsumoto Takehiro - - 2003
BACKGROUND: Angiotensin (Ang) II, which plays a crucial role in the cardiac remodeling process, is generated via angiotensin-converting enzyme (ACE); however, an alternative generation pathway, chymase, which is stored in the mast cells, also exists in the heart. Cardiac chymase is insensitive to ACE inhibitors (ACEIs), and heart chymase promotes ...
Chuang Yao-Chung - - 2003
Coenzyme Q10 (CoQ10, ubiquinone) is a highly mobile electron carrier in the mitochondrial respiratory chain that also acts as an antioxidant. We evaluated the neuroprotective efficacy of CoQ10 against fatality in an experimental model of endotoxemia that mimics systemic inflammatory response syndrome using a novel water-soluble formulation of this quinone ...
Morgan Trefor - - 2003
Angiotensin II and sodium balance affect the status of each other and both--either separately or together--can lead to an increase in blood pressure. They also can cause vascular and cardiac damage due to direct effects and effects mediated by the blood pressure increase. This paper reviews the important interactions among ...
Ullman J - - 2003
BACKGROUND: General anaesthesia may stimulate the renin-angiotensin system. Exogenous administration of angiotensin II elevates blood pressure mainly via increased total peripheral resistance caused by direct vasoconstrictor actions. It is also well established that the hypertensive effect of angiotensin II involves a cerebrally mediated component. The hypertensive effect of an intravascular ...
Veerasingham Shereeni J - - 2003
This review focuses on the dysfunction of the intrinsic brain renin-angiotensin system (RAS) in the pathogenesis of hypertension. Hyperactivity of the brain RAS plays a critical role in mediating hypertension in both humans and animal models of hypertension, including the spontaneously hypertensive rat (SHR). The specific mechanisms by which increased ...
de Wit Cor - - 2003
Gap-junctional communication coordinates the behavior of individual cells in arterioles. Gap junctions are formed by connexins 40 (Cx40), Cx43, Cx37, and Cx45 in the vasculature. Previously, we have shown that lack of Cx40 impairs conduction of dilatory signals along arterioles. Herein, we examined whether hypertension is present in conscious animals ...
De Smet H R - - 2003
1. Angiotensin (Ang) II causes cardiac hypertrophy in vitro and in vivo. It also stimulates the release of endothelin (ET)-1. Endothelin-1 induces hypertrophy of cardiomyocytes in vitro. 2. In the present study, we examined whether the cardiac hypertrophic action of AngII in vivo was mediated by ET-1 via ETA receptors. ...
Kashihara Koji - - 2003
Although the elevation of angiotensin II (Ang II) associated with cardiovascular diseases has been considered to suppress the arterial baroreflex function, how Ang II affects dynamic arterial pressure (AP) regulation remains unknown. The aim of the present study was to elucidate the acute effects of Ang II on dynamic AP ...
Shimizu Toshihiro - - 2003
OBJECTIVE: Coronary microcirculation plays an important role in the progression of cardiac remodeling. Among angiogenic factors, it has been reported that angiotensin II may contribute to neovascularization. However, it is unknown whether inhibition of the renin-angiotensin system suppresses angiogenesis, especially within the heart. Our aim was to evaluate the effects ...
Reckelhoff Jane F - - 2003
Infusion of ANG II at a rate not sufficient to evoke an immediate vasoconstrictor response, produces a slow increase in blood pressure. Circulating levels of ANG II may be within ranges found in normotensive individuals, although inappropriately high with respect to sodium intake. When ANG II levels are dissociated from ...
Ferrario Carlos M - - 2003
Increased understanding of the contribution of angiotensin peptides to the physiologic control of arterial pressure and cardiovascular regulation has been made possible with the introduction of agents that either inhibit the activity of angiotensins forming enzymes or block the action of the peptides at their specific receptor subtypes. This review ...
Asiedu-Gyekye Isaac Julius - - 2003
BACKGROUND: The purpose of this study was to ascertain the effect of Losartan, a non-peptide angiotensin II receptor antagonist used for the treatment of hypertension, on the movement of proteins and fluids across the vascular compartment in ischemic cat brains. MATERIAL/METHODS: The experiments were carried out on anesthetized cats under ...
Fuchsjäger-Mayrl Gabriele - - 2003
PURPOSE: There is evidence that the choroid has some autoregulatory capacity in response to changes in ocular perfusion pressure (OPP). The mediators of this response are hitherto unidentified. The hypothesis for the current study was that endothelin (ET)-1 and/or angiotensin (ANF)-II may be involved in choroidal vasoconstriction during an increase ...
Hassan Ghada S - - 2003
Recent studies have shown that the vasoactive peptide urotensin-II (U-II) exerts a wide range of action on the cardiovascular system of various species. In the present study, we determined the in vivo effects of U-II on basal hemodynamics and cardiac function in the anesthetized intact rat. Intravenous bolus injection of ...
Vittorio Timothy J - - 2003
A synergistic interaction between the angiotensin II (Ang II) type 1 receptor and alpha1-adrenergic receptors has been described. We hypothesized that the nonselective beta-antagonist carvedilol, through its alpha1-adrenergic blocking properties, may modulate vascular reactivity to Ang II in patients with chronic heart failure (CHF). Accordingly, we compared the vasopressor response ...
Pamidimukkala Jaya - - 2003
It has been suggested that estrogen modulates baroreflex regulation of autonomic function. The present study evaluated the effects of estrogen on baroreflex regulation of heart rate in response to changes in blood pressure with phenylephrine (PE), ANG II, and sodium nitroprusside (SNP) in a conscious mouse model. Males and ovariectomized ...
Neves Mario Fritsch - - 2003
BACKGROUND: Angiotensin (Ang) II stimulates aldosterone production, which may mediate some of the effects of Ang II. OBJECTIVE: To test whether Ang II-induced structural and mechanical changes in resistance arteries may be prevented by the non-selective aldosterone receptor blocker, spironolactone, independently of reduction in blood pressure. METHODS: Male Sprague-Dawley rats ...
Takai Shinji - - 2003
NK3201 is an orally active chymase inhibitor. Its inhibitory activity leads to formation of acyl-intermediate between active serine residue of the enzyme and di-ketone structure of NK3201. NK3201 inhibits human, dog and hamster chymases with IC(50) of 2.5, 1.2, and 28 nM, respectively. On the other hand, NK3201 does not ...
Blake Duncan W - - 2003
1. The effects of thoracic intrathecal doses (1 microg/kg) of the alpha2-adrenoceptor agonist dexmedetomidine and omega-conotoxins MVIIA and CVID on vasoconstrictor and heart rate responses to acute central hypovolaemia were studied in seven chronically instrumented rabbits. 2. Gradual inflation of an inferior vena cava cuff to reduce cardiac index (CI) ...
Nakamura Shigefumi - - 2003
This study evaluated the contribution of angiotensin peptides acting at various receptor subtypes to the arterial pressure and heart rate of adult 9-wk-old male conscious salt-depleted spontaneously hypertensive rats (SHR). Plasma ANG II and ANG I in salt-depleted SHR were elevated sevenfold compared with peptide levels measured in sodium-replete SHR, ...
Lin Yingzi - - 2003
OBJECTIVE: To examine the central cardiovascular action of urotensin II in conscious rats. METHODS: Intracerebroventricular (ICV) injections of urotensin II (1 and 10 nmol) were carried out in conscious Wistar rats. The effects of intravenous (i.v.) urotensin II (10 nmol) were also determined. RESULTS: The ICV injection of urotensin II ...
González Arantxa - - 2002
Collagen types I and III (Col I and Col III) are the major fibrillar collagens produced by fibroblasts and myofibroblasts in the adult heart. Fibrillar collagen of the heart provides the structural scaffolding for cardiomyocytes and coronary vessels and imparts cardiac tissue with physical properties that include stiffness and resistance ...
Rocha Ricardo R Pharmacia Corporation, Cardiovascular and Metabolic Diseases, Skokie, Illinois 60077 and St. Louis, Missouri 63167, USA. - - 2002
We studied the role of aldosterone (aldo) in myocardial injury in a model of angiotensin (Ang) II-hypertension. Wistar rats were given 1% NaCl (salt) to drink and randomized into one of the following groups (n = 10; treatment, 21 d): 1) vehicle control (VEH); 2) Ang II infusion (25 ng/min, ...
Affolter Jonathan T JT Clinical Research Centre, Department of Medical Sciences, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, - - 2002
In rodent and primate studies, urotensin II is an extremely potent vasoconstrictor peptide with effects in the central aortic and arterial vasculature as well as on cardiac function. The aim of the present study was to assess systemic haemodynamic responses to intravenous urotensin II infusion in humans. In 10 healthy ...
Xue Baojian - - 2003
This study reports the effects of angiotensin II (ANG II), arginine vasopression (AVP), phenylephrine (PE), and sodium nitroprusside (SNP) on baroreflex control of heart rate in the presence and absence of the area postrema (AP) in conscious mice. In intact, sham-lesioned mice, baroreflex-induced decreases in heart rate due to increases ...
Alzamora A C - - 2002
The objective of the present study was to determine the contribution of the autonomic nervous system and nitric oxide to the depressor effect produced by unilateral microinjection of ANG-(1-7) and ANG II into the caudal ventrolateral medulla (CVLM). Unilateral microinjection of ANG-(1-7), ANG II (40 pmol), or saline (100 nl) ...
Booz George W - - 2002
Recent studies have shown that the JAK-STAT signaling pathway plays a central role in cardiac pathophysiology. JAK-STAT signaling has been implicated in pressure overload-induced cardiac hypertrophy and remodeling, ischemic preconditioning, and ischemia/reperfusion-induced cardiac dysfunction. The different STAT family members expressed in cardiac myocytes appear to be linked to different, and ...
Bealer Steven L - - 2003
Increased dietary sodium enhances both excitatory and inhibitory blood pressure responses to stimulation of the central sympathetic nervous system (SNS) centers. In addition, long-term (hours to days) administration of ANG II increases blood pressure by activation of the SNS. These studies investigated the effects of increased dietary sodium on SNS ...
Andersen Niels Holmark - - 2002
Several treatment guidelines have made strong recommendations to physicians that treatment of nephropathy and hypertension should be based on the use of a long-acting angiotensin converting enzyme (ACE) inhibitor if tolerated. The recently published clinical trials, based on angiotensin II receptor blockers' effects on diabetic nephropathy and essential hypertension, have ...
Lameris Thomas W - - 2002
Studies on the effect of angiotensin II on norepinephrine release from sympathetic nerve terminals through stimulation of presynaptic angiotensin II type 1 receptors are equivocal. Furthermore, evidence that angiotensin II activates the cardiac sympathetic nervous system in vivo is scarce or indirect. In the intact porcine heart, we investigated whether ...
Wilfert K - - 2002
Atherosclerosis is associated with increased angiotensin II AT1-receptor expression and vascular hyperresponsiveness to angiotensin II. Nevertheless, atherosclerosis is often not accompanied by hypertension. We studied if the hypertensive effect of angiotensin II is more pronounced in atherosclerosis. Rabbits were fed a high-cholesterol diet (n = 10) for 12 weeks, followed ...
Leong Patrick K K - - 2002
Acute hypertension inhibits proximal tubule (PT) fluid reabsorption. The resultant increase in end proximal flow rate provides the error signal to mediate tubuloglomerular feedback autoregulation of renal blood flow and glomerular filtration rate and suppresses renal renin secretion. To test whether the suppression of the renin-angiotensin system during acute hypertension ...
Ramchandra Rohit - - 2002
1. Chronic administration of angiotensin (Ang) II causes an increase in blood pressure via a multitude of actions, including direct vasoconstriction, hypertrophy and increased sympathetic nerve activity. In the present study, we assessed whether the hypertension resulting from chronic Ang II alters the ability of the renal vasculature to respond ...
Smith David H G - - 2002
The continued poor rates of blood pressure (BP) control to the recommended target BP of <140/90 mm Hg in patients with hypertension indicate a persistent need for improved antihypertensive therapy. Angiotensin II receptor blockers (ARBs) constitute the newest approved class of antihypertensive agents. As with angiotensin converting enzyme inhibitors, ARBs ...
Ferrario Carlos M CM The Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, - - 2002
Omapatrilat, a new vasopeptidase inhibitor, inhibits the activity of angiotensin-converting enzyme (ACE) and neutral endopeptidase 24.11 (NEP). Because these two enzymes participate in the degradation of the vasodilator and natriuretic peptide, angiotensin-(1-7) [Ang-(1-7)], we assessed whether omapatrilat treatment is associated with changes in the plasma and urinary excretion rates of ...
Lu Yang - - 2002
It has been shown that intracerebroventricular injection of urotensin II (UII)-induced hypotensive and bradycardiac responses. Here, we tested the cardiovascular roles of UII in different brain areas by microinjection of UII into the A1 and A2 areas (noradrenergic cells found in the lower part of the medulla that have been ...
Abrahamsen Christian T - - 2002
The role of angiotensin II (AII) and angiotensin IV (AIV) as inducers of PAI-1 expression during hypertension was studied in vivo. A 2-week infusion of AII (300 ng/kg/min) via an osmotic pump increased systolic blood pressure (171 +/- 2 vs. 138 +/- 6 mm Hg), urinary protein excretion (32 +/- ...
Velaphi Sithembiso C - - 2002
Angiotensin II (ANG II) increases blood pressure (MAP) via specific ANG II receptors (AT) and is considered important in regulating MAP after birth. In adult animals, AT(1) receptors predominate in vascular smooth muscle (VSM) and mediate vasoconstriction. In newborn sheep, AT(2) receptors, which do not mediate vasoconstriction, predominate in vascular ...
Li Peng - - 2002
The role of a dual angiotensin (Ang) II-forming pathway from the local renin angiotensin system (RAS) of the cardiac tissue was determined in a hamster model of cardiac hypertrophy. Time-dependent expressions of chymase and angiotensin converting enzyme (ACE) genes and their enzymes activities, and Ang II levels were measured in ...
Harada Sanae - - 2002
This study was designed to test the hypothesis that increased pressure itself could cause endothelial dysfunction and lead to decreased nitric oxide (NO) release, partly through effects on the tissue renin angiotensin system in hypertension. Cultured endothelial cells (ECs) isolated from the aortas of WKY rats were continuously exposed to ...
Ferreira A J - - 2002
We evaluated the effects of angiotensin-(1-7) (Ang-(1-7)) on post-ischemic function in isolated hearts from adult male Wistar rats perfused according to the Langendorff technique. Local ischemia was induced by coronary ligation for 15 min. After ischemia, hearts were reperfused for 30 min. Addition of angiotensin II (Ang II) (0.20 nM, ...
Sadjadi Javid - - 2002
The mechanism by which hypertension is maintained in renovascular hypertension remains poorly defined. Because plasma angiotensin II does not correlate with blood pressure in RVH, we postulated that activation of tissue-specific autocrine-paracrine renin-angiotensin systems may upregulate local production of angiotensin II and maintain hypertension in chronic RVH. RVH was induced ...
Thavarajah Sumeska - - 2002
Both basic and experimental data indicate that the renin-angiotensin system through angiotensin II mediates its classic hemodynamic role, but also has a significant deleterious role in a number of cardiac, vascular, and renal disorders. Indeed, evidence indicates that angiotensin II negatively impacts endothelial function, cardiac remodeling, vessel wall hypertrophy, atherosclerosis, ...
Abdelrahman Aly M - - 2002
This study examined if the nitric oxide (NO)/L-arginine pathway participates in and if the sympathetic nervous system attenuates the depressor action of human urotensin II. I.V. bolus injections of human urotensin II (0.1-30 nmol/kg) caused dose-dependent decreases in mean arterial pressure (MAP, EC(50) = 2.09 +/- 0.8 nmol/kg; Emax = ...
Mayan Haim - - 2002
Mutations in WNK kinases cause pseudohypoaldosteronism type II (PHA II) and may represent a novel signaling pathway regulating blood pressure and K(+) and H(+) homeostasis. PHA II is an autosomal dominant disorder characterized by hypertension, hyperkalemia, and metabolic acidosis, with normal glomerular filtration rate. Thiazide diuretics correct all abnormalities. Inactivating ...
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