Search Results
Results 451 - 500 of 1269
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Verma S - - 1999
The fructose-induced hypertensive rat is a widely used model to study the inter-relationship between hyperinsulinemia, insulin resistance and high blood pressure. Evidence suggests that hyperinsulinemia and insulin resistance may be pathogenic in the development of high blood pressure in this model. To determine the contribution of the sympathetic nervous system ...
Hügel S - - 1999
The purpose of this study was to define the dose-dependent effects of 17beta-estradiol on coronary flow and cardiac function in isolated rat hearts and to identify the mechanisms involved in its vasodilator action. Hearts from female and male Wistar rats were perfused at constant pressure (100 mm Hg). Stereoisomer specificity ...
Dobrian A - - 1999
We previously demonstrated remodeling of large and small arteries in angiotensin II-treated rats, paralleled by an increased expression of platelet-derived growth factor (PDGF)-A chain mRNA in large arteries. Both remodeling and PDGF-A expression were associated with elevation of blood pressure rather than a direct effect of angiotensin II. To further ...
Kaide J - - 1999
The importance of increased endogenous digitalis-like factor (EDLF) in volume-expanded hypertension has been generally agreed. To further clarify the role of EDLF on the development of hypertension and renal water-sodium handling in 5/6 reduced renal mass hypertensive rats (RRM), we studied the effects of acute administration of digoxin-specific antibody Fab ...
Rahmouni K - - 1999
Brain mineralocorticoid receptors appear to contribute to mineralocorticoid hypertension and may be involved in blood pressure control in normotensive rats. We examined the effect of blockade of central mineralocorticoid receptors with the use of a selective antagonist (RU28318) on cardiovascular and renal function in conscious normotensive rats. The contribution of ...
Witte K - - 1999
TGR(mREN2)27 (TGR) rats are transgenic animals with an additional mouse renin gene, which leads to overactivity of the renin-angiotensin system. Adult TGR rats are characterized by fulminant hypertension, hypertensive end-organ damage, and an inverse circadian blood pressure pattern. To study the ontogenetic development of cardiovascular circadian rhythms, telemetric blood pressure ...
Laurant P - - 1999
The purpose of this study was to determine the effect of dietary Mg deficiency (80 mg/kg versus control diet: 960 mg/kg) on blood pressure and mechanical properties of the rat common carotid artery. The internal diameter and intra-arterial pressure of carotid artery were measured continuously with an echo-tracking device. At ...
Wang J - - 1999
We tested whether ouabain, an inhibitor of the sodium pump, can lead to chronic hypertension in Long-Evans rats using sensitive 24-h measurements of blood pressure. After a control week of vehicle isotonic saline infusion (14.4 mL/day), ouabain was infused intravenously at 30 microg/kg/day in intact (2K) and uninephrectomized (1K) Long-Evans ...
Karson A B - - 1999
Gamma-aminobutyric acid (GABA) plays an important role in both central cardiovascular homeostasis and pathogenesis of epileptic seizures. Previous studies have indicated a critical role of the amygdala in the spread of seizures from brainstem to forebrain and in the regulation of autonomic responses such as blood pressure and heart rate. ...
Schinke M - - 1999
Angiotensin produced systemically or locally in tissues such as the brain plays an important role in the regulation of blood pressure and in the development of hypertension. We have established transgenic rats [TGR(ASrAOGEN)] expressing an antisense RNA against angiotensinogen mRNA specifically in the brain. In these animals, the brain angiotensinogen ...
Sitniewska E - - 1999
The present study was aimed to determine the cardiovascular effects of secretin in healthy rats and rats with streptozotocin-induced diabetes mellitus. In vivo studies involved measurements of the systolic and diastolic blood pressure, and heart rate of rats given secretin at the following doses: 0.75; 1.5; 3.0 mumol/kg. In vitro, ...
Ferrari P - - 1999
A genetic alteration in the adducin genes is associated with hypertension and up-regulation of the expression of renal Na, K-ATPase in Milan-hypertensive (MHS) rats, in which increased ouabain-like factor (OLF) levels are also observed. PST 2238, a new antihypertensive compound that antagonizes the pressor effect of ouabain in vivo and ...
Cicila G T - - 1999
Interval mapping was used to identify putative quantitative trait loci (QTL) for blood pressure and cardiac mass on Chromosome (Chr) 3 in F1(S x R) x S population of 150 rats raised on an 8% NaCl diet. Two genetic markers 95.7 cM apart, D3Wox3 and D3Mco5 (tightly linked to Edn3), ...
Mangos, George Jack
Models of steroid-induced hypertension in man and rat have been well characterized but the mechanisms by which ACTH and glucocorticoids raise blood pressure are not fully understood. Recently described paracrine (eg endothelial nitric oxide) and humoral (eg PHF) factors may be important in human essential hypertension. These factors were examined ...
Mori S - - 1999
The histopathological changes in denture-supporting tissues of streptozotocin-induced diabetes mellitus rat were studied in relation to continuous mechanical pressure exerted through an experimental denture base. The experimental dentures were designed to load continuous mechanical pressures (3.4, 1.5 or 0.5 kPa) to the hard palate of the molar region of a ...
Hashimoto M - - 1999
Fish oils have been shown to lower blood pressure in hypertensive subjects. To determine the mechanism of this hypotensive effect, we examined the effects of docosahexaenoic acid (DHA), one of the (n-3) polyunsaturated fatty acids in fish oil, on blood pressure and on the release of adenyl purines, such as ...
Törnig J - - 1999
Wall thickening of intramyocardial arteries in patients with chronic renal failure may contribute to the increased susceptibility of the uremic heart to ischemic injury. In this context, the following questions arise: (1) Is intramyocardial wall thickening in experimental renal failure due to hypertrophy, hyperplasia or both? (2) Which stimuli trigger ...
Marmarelis V Z - - 1999
This article presents results of the use of a novel methodology employing principal dynamic modes (PDM) for modeling the nonlinear dynamics of renal autoregulation in rats. The analyzed experimental data are broadband (0-0.5 Hz) blood pressure-flow data generated by pseudorandom forcing and collected in normotensive and hypertensive rats for two ...
Abete P - - 1999
Oxygen radical-mediated injury has been implicated in the process of cardiac aging. We investigated the tolerance to oxidative stress of hearts from rats of different age. Langendorff-perfused hearts from 3-12-month-old rats received a 30 min infusion of the reactive oxygen specie hydrogen peroxide (H2O2, 60 microM), followed by a 15 ...
Holemans K - - 1999
Food restriction during pregnancy in rats induces intrauterine growth retardation with consequences persisting into adulthood. In the present study we have investigated the hypothesis that malnutrition in pregnant rats may lead to altered cardiovascular function in adult female offspring. Perinatal growth retardation was induced by a 50% reduction of normal ...
Sharkey L C - - 1998
The importance of the loss of ovarian function to the progression of hypertension and heart disease in women is controversial. We investigated whether ovariectomy would accelerate development of hypertension, congestive heart failure, and neurohumoral activation in adult spontaneous hypertension heart failure (SHHF) rats, a genetic model of heart failure. Six ...
Schiffrin E L - - 1998
The endothelins (ET) are potent 21-amino-acid vasoconstrictor peptides produced in many different tissues, particularly in the endothelium of blood vessels. ET-1 is the main endothelin secreted by the endothelium, and acts in a paracrine or autocrine fashion on blood vessels by interacting with ETA or ETB receptors on smooth muscle ...
Martin D S - - 1998
Animals with bilateral cannulas in the paraventricular nucleus were made hypertensive by a one-kidney, figure eight renal wrap procedure or sham operated. Femoral artery and vein catheters were inserted for arterial pressure measurement and plasma catecholamine determination. After recovery and 4 days after hypertension surgery, bicuculline methiodide or muscimol was ...
Nakajima Y - - 1998
To gain better insights into the effect of dehydration on thermal and cardiovascular regulation during hyperthermia, we examined these regulatory responses during body heating in rats under isosmotic hypovolemia and hyperosmotic hypovolemia. Rats were divided into four groups: normovolemic and isosmotic (C), hypovolemic and isosmotic [L, plasma volume loss (DeltaPV) ...
Anderson I K - - 1998
The cardiovascular profile of the angiotensin AT1 receptor antagonist, GR138950, and the influence of potential compensatory homeostatic mechanisms on this profile, were investigated in renal artery ligated hypertensive (RALH) rats. GR138950 caused a marked reduction in blood pressure associated with immediate tachycardia in conscious RALH rats. The antihypertensive action of ...
Masilamani S - - 1998
With advancing age, there is a generalized reduction in the ability of the kidney to generate a natriuretic response and, in addition, the incidence of salt-sensitive hypertension increases. One event that could link these changes is a defect that develops in the pressure natriuresis response of the old kidney. To ...
Zimmer H G - - 1998
After a brief historical account of the methods for pressure measurements in the cardiovascular system, the basic structural elements of a new generation of miniaturized catheter pressure transducers are described. These catheters have an outside diameter at the tip of 0.9 mm (3 French) and have been routinely applied in ...
Talmor D - - 1998
Phenylephrine-induced hypertension (increase of 30-35 mm Hg for 15 min) is reported to increase cerebral perfusion pressure and collateral flow to ischemic areas of the brain in a rat model of focal cerebral ischemia. In the present study, we examined whether phenylephrine-induced hypertension of similar magnitude and duration was beneficial ...
Amann K - - 1998
BACKGROUND: In view of the high rate of cardiac death in renal failure, the factors involved in the genesis of structural changes in the heart are of obvious interest. The present study addresses the issue whether growth factors known to be involved in cardiac remodelling are abnormally expressed in rats ...
Van Bergen P - - 1998
In conscious rats, gamma2-melanocyte-stimulating hormone (gamma2-MSH) dose-dependently increases blood pressure and heart rate, whereas adrenocorticotropin-(1-24) [ACTH-(1-24)] dose-dependently decreases blood pressure, an effect which was accompanied by a reflectory tachycardia. As the exact mechanism involved in these cardiovascular effects of the two melanocortins is as yet not known, we undertook a ...
Lee R J - - 1998
Atrioventricular (AV) block is a useful substrate for the study of cardiac physiology. The objective of this investigation was to develop a straightforward and reproducible model of permanent AV block in rats. Working through a sternotomy, we used an epicardial fat pad between the aortic root and the right atrial ...
Chang K C - - 1998
This study was designed to explore the changes of mechanical properties in the rat's arterial system at different ages by using the exponentially tapered T-tube model. Long-Evans male rats at the ages of 6, 12, and 18 months were anesthetized and thoractomized. Rats at the ages of 6, 12, and ...
Chang K C - - 1998
Methoxamine, a specific alpha1-selective adrenoceptor agonist, has proven to be useful in the treatment of hypotension, especially hypotension due to failure of the sympathetic nervous system. This study is to explore the vascular dynamic response to methoxamine in Wistar-Kyoto rats, based on the exponentially tapered T-tube model. The pulsatile aortic ...
Synnerstad I - - 1998
BACKGROUND & AIMS: The gastroprotective properties of prostaglandins in low concentrations are still unclear. In this study, we investigated the effects of prostaglandin E2 (PGE2), indomethacin, and intraluminally applied HCl or ethanol on intraglandular pressure, mucus thickness, acid secretion, and gastric mucosal blood flow. METHODS: Glandular pressure and mucous gel ...
Ye S - - 1998
Previously, we have shown that an acute injury to the kidney produced by an intrarenal injection of phenol causes an immediate increase in blood pressure and in norepinephrine (NE) secretion from the posterior hypothalamus. The studies suggest that in this model afferent impulses from the kidney to central integrative structures ...
Sharifi A M - - 1998
OBJECTIVES: To determine whether an angiotensin converting enzyme inhibitor, enalapril, and a dihydropyridine calcium channel antagonist, amlodipine, regress the altered structure, media composition, and vascular relaxation of small arteries of spontaneously hypertensive rats. METHODS: Spontaneously hypertensive rats aged 10 weeks were treated for 12 weeks with 10 mg/kg per day ...
Mok S L - - 1998
Intravenous injection of the aspidofractinine alkaloid, kopsingine (1, 0.2-10.0 mg/kg) from Kopsia teoi, produced dose-related decreases in the mean arterial blood pressure and heart rate in anesthetized spontaneously hypertensive rats, which were similar to those seen in normotensive controls. Minor modifications in the molecular structure of kopsingine, as in kopsaporine ...
Takizawa H - - 1998
Lipoxygenase inhibitors reduce blood pressure in hypertensive rats. The vasodepressor effect of lipoxygenase inhibitors may be related to increased production of prostaglandin (PG) I2 since lipoxygenase-derived fatty acid hydroperoxides inhibit PGI2 synthase. This hypothesis was examined in rats made hypertensive by infusion of angiotensin II (200 ng/min i.p.) for 12 ...
Blank S D - - 1998
BACKGROUND: Although cardioplegic protection of the hypertrophied heart remains a clinical challenge, we have previously observed enhanced recovery in rat hearts with pressure-overload hypertrophy induced by aortic banding. We investigated whether this unexpected result is found in other models of hypertrophy. METHODS: Hearts with hypertrophy induced by aortic banding or ...
Michael O'Donnell J - - 1998
31P-NMR was used to monitor myocardial bioenergetics in compensated and failing SHHF/MCC-fa(cp) (SHF) rat hearts. The SHHF/Mcc-fa(cp) (spontaneous hypertension and heart failure) rat is a relatively new genetic model in which all individuals spontaneously develop congestive heart failure, most during the second year of life. Failing SHF rat hearts displayed ...
Brouwer, Marie Christine
The aim of this project is the design of a proficient replacement of the live-lab animal experiment 'blood pressure regulation in the rat' with special attention to the teaching of ethical conscuouscness. ... Zie: Introduction
Richey J M - - 1998
We demonstrated that the fructose-induced hypertensive rat, representative of the principal metabolic abnormalities found in a majority of hypertensive patients, i.e. hypertriglyceridemia, hyperinsulinemia and insulin resistance (Syndrome X), is associated with an impaired response to endothelium-dependent vasodilators and that fructose may directly contribute to this impairment. Twelve male Wistar rats ...
Molino P - - 1998
A windkessel model was applied on a beat-to-beat basis to evaluate the arterial mechanical characteristics in seven conscious rats. Ascending aortic arterial pressure (AP) and blood flow were recorded during steady-state in basal conditions, during infusions of isoprenaline, sodium nitroprusside, and phenylephrine, and after intravenous atenolol injection. For each cardiac ...
Supowit S C - - 1998
We previously demonstrated that the neuronal expression of calcitonin gene-related peptide (CGRP), a potent vasodilator, is increased in deoxycorticosterone-salt-induced hypertension where it acts as a compensatory vasodilator to attenuate the elevated blood pressure. To determine whether CGRP is playing a similar role in subtotal nephrectomy-salt-induced hypertension, hypertension was induced in ...
Somody L - - 1998
The way in which the cardiovascular system adapts to weightlessness is still under discussion. No data are yet available on the responses of rats during space flight, although this animal is commonly used in simulation studies. We have designed and tested a protocol to study the short term responses of ...
Hashimoto M - - 1998
Fish oils have been shown to lower blood pressure in hypertensive subjects. All-cis-5,8,11,14,17-icosapentaenoate (EPA), one of the omega-3 polyunsaturated fatty acids, is known to be one of the major active components in fish oil that has beneficial effects on the cardiovascular system. However, little is known about the antihypertensive effect ...
Zhang Z B - - 1998
AIM: To investigate the effects of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino) propane hydrochloride (DDPH) on cardiac systolic and diastolic function, lactate dehydrogenase (LDH) activity, and LDH isoenzymes in rats with cardiac hypertrophy. METHODS: The cardiac hypertrophy of rats was induced by partly occluding abdominal aorta. The rats were given i.g. DDPH for 8 wk ...
Kim S Y - - 1997
Mivazerol, 3-[1(H-imidazol-4-yl)methyl]-2-hydroxybenzamide hydrochloride, is a selective alpha 2-adrenoceptor agonist designed for the prevention of myocardial infarction in perioperative patients. Because unintended hypothermia occurs frequently during surgery, we were interested, in this study, to examine the relationship between body temperature and the bradycardic response induced by mivazerol. Experiments were carried out ...
Capers Q Q - - 1997
Monocyte chemoattractant protein-1 (MCP-1), a potent monocyte chemoattractant synthesized by vascular cells and monocytes, has been proposed to be an important mediator of inflammatory responses in the arterial vasculature. It was recently demonstrated that hypertension is associated with an inflammatory response in the arterial wall. To determine the effect of ...
Cicila G T - - 1997
11 beta-hydroxylase (Cyp11b1) mutations were previously linked to altered steroid biosynthesis and blood pressure in Dahl salt-resistant (R) and Dahl salt-sensitive (S) rats. In the present work, interval mapping identified a putative blood pressure quantitative trait locus (QTL) near Cyp11b1 in an F1(SxR)xS population (LOD = 2.0). Congenic rats (Designated ...
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