Search Results
Results 351 - 400 of 1444
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Kishi Takuya - - 2002
We have previously demonstrated that the overexpression of endothelial NO synthase (eNOS) in the rostral ventrolateral medulla (RVLM) decreases blood pressure, heart rate, and sympathetic nerve activity via an increase in gamma-amino butyric acid release in normotensive Wistar-Kyoto rats (WKY). Stroke-prone spontaneously hypertensive rats (SHRSP) appear to have reductions of ...
Sipola Marika - - 2002
The effect of long-term intake of two fermented milk products on the development of hypertension was compared in young spontaneously hypertensive rats (SHR). The products contained tripeptides isoleucine-proline-proline (IPP) and valine-proline-proline (VPP), which have been shown to possess angiotensin converting enzyme (ACE) inhibitory activity. Six-week-old SHR were divided into four ...
Raasch Walter - - 2002
Since agmatine has been identified as a clonidine displacing substance (CDS), the aim of this study was to investigate whether agmatine can mimic CDS-induced cardiovascular reactions in organ bath experiments, pithed spontaneously hypertensive rats (SHR) and anaesthetized SHR. Intravenously-administered agmatine significantly reduced the blood pressure and heart rate of anaesthetized ...
Christiansen Rolf E F - - 2002
BACKGROUND/AIMS: Cross-transplantation studies between animals with genetic hypertension and normotensive animals indicate a key role of the kidney in development of hypertension, and studies in young spontaneously hypertensive rats (SHR) have shown reduced glomerular filtration rate (GFR) and renal blood flow (RBF) for a short period at the age of ...
Sabbatini Maurizio - - 2002
The effects of hypertension and of treatment with dihydropyridine-type Ca2+ antagonists and the vasodilator hydralazine on renal arterial tree were investigated in spontaneously hypertensive rats (SHR) with quantitative microanatomical techniques. Pharmacological treatment decreased to a similar extent systolic blood pressure values in SHR. Increased thickness of the tunica media of ...
Sato Minoru - - 2002
AIM: The angiotensin-I-converting enzyme (ACE) inhibitory and antihypertensive activities of wakame hydrolysates have been investigated in several studies. METHODS: Wakame (Undaria pinnatifida) was hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for ACE was measured. Of these hydrolysates 4 with potent ACE inhibitory activity were ...
Han Shaojie - - 2002
Chronic treatment with Salvia Miltiorrhiza preventing left ventricular hypertrophy (LVH) and its possible mechanism--inhibiting the action of cardiac aldosterone in spontaneously hypertensive rats (SHR) were investigated. Normotensive Wistar-kyoto (WKY) rats and SHRs were used. Part of SHRs was treated with Salvia Miltiorrhiza for 12 weeks. Systolic blood pressure (SBP) and ...
Mizutani Ken-ichi - - 2002
The rostral ventrolateral medulla (RVLM) plays a critical role in the tonic and reflexive regulation of arterial blood pressure. Recent studies have demonstrated that injection of kynurenic acid (KYN) into the RVLM of spontaneously hypertensive rats (SHR) decreases arterial blood pressure. We hypothesized that a relative increase in the excitatory ...
Kim Choong-Yong CY Laboratory Animal Science, Asan Institute for Life Sciences, University of Ulsan, 388-1 Poongnap-dong, Songpa-ku, Seoul 138-736, - - 2002
Effects of maternal-melatonin treatment in spontaneously hypertensive rats (SHR) were investigated in their offspring. Pregnant SHR were given drinking water with/without melatonin (20 micrograms melatonin/ml tap water) during pregnancy and the lactation period. Maternal-melatonin treatment did not cause changes in body weights during 7 to 27 weeks. Melatonin administration up ...
Safar M - - 2001
In rats, removal of the carotid arterial or abdominal aortic endothelium results in an acute increase of diameter and compliance. In humans, acute local administration of a specific NO synthase inhibitor increases radial artery compliance but not the diameter. The purpose of this review is to determine whether in spontaneously ...
Susic D - - 2001
This study was designed to examine the preventability of progressive deterioration of cardiovascular structure and function in very old Wistar-Kyoto (WKY) rats with isolated systolic hypertension (ISH). To this end, male 18-month-old normotensive WKY rats were given either placebo or L-arginine (70 mg. kg(-1). d(-1)) and an ACE inhibitor (enalapril, ...
Fang Z - - 2001
In women, arterial pressure generally increases after menopause, but several studies suggest that women who eat large amounts of plant estrogens (phytoestrogens) experience a slower rise in the incidence of postmenopausal hypertension. This suggests that both ovarian hormones (principally estrogen) and phytoestrogens may protect at least some women from hypertension. ...
Al-Shafei A I - - 2001
Right ventricular structure and function were characterized in spontaneously hypertensive rats (SHR) using non-invasive magnetic resonance imaging (MRI) techniques. These studies therefore complement previous reports preoccupied with left ventricular changes associated with this condition. Eight SHR and eight control normotensive Wistar-Kyoto (WKY) rats were each subdivided into equal age-matched groups ...
Ayada Y - - 2001
Biglycan mRNA expression in rat myocardium after abdominal aortic banding with renal ischemia was examined. The Northern blot analysis demonstrated that expression of biglycan mRNA in the pressure-overloaded hearts on days 2, 7, 14 and 28 was 2.88 +/- 0.89, 2.32 +/- 0.49, 2.17 +/- 0.57 and 1.81 +/- 0.46-fold ...
Calhoun D A - - 2001
OBJECTIVE: We have reported that acute administration of enalaprilat, an angiotensin converting enzyme inhibitor, induces less reflexive increase in lumbar sympathetic nerve activity in spontaneously hypertensive rats (SHRs) than nicardipine, a dihydropyridine calcium-channel blocker. The current study was conducted to determine if angiotensin converting enzyme inhibitors likewise suppress cardiac sympathetic ...
Seyedabadi M - - 2001
Spontaneously hypertensive rats (SHR) are characterized by extreme elevations of blood pressure. The genetic factors underlying this are yet to be identified. Here we demonstrate, in vivo, that in SHR and normotensive Wistar-Kyoto rats (WKY), injection of the mitogen-activated protein kinase inhibitor PD 098,059 bilaterally into the rostral ventrolateral medulla ...
Bund S J - - 2001
This investigation related arterial structure to myogenic (pressure-dependent) contractile responses in resistance arteries from spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) normotensive control rats under pressurized conditions in vitro. Femoral and mesenteric resistance arteries from either strain were cannulated and pressurized in an arteriograph for the determination of pressure-diameter relationships ...
Yamamoto K - - 2001
The effects of NG-nitro-L-arginine (L-NNA) on blood pressure of various strains of spontaneously hypertensive rats were studied. Blood pressure of the rats was higher in the order of WKY, SHR, SHRSP, M-SHRSP. L-NNA caused an elevation of the blood pressure, which was greatest in SHR and smallest in WKY and ...
Osanai T - - 2001
We demonstrated recently that coupling factor 6, an essential component of the energy-transducing stalk of mitochondrial ATP synthase, suppresses the synthesis of prostacyclin in vascular endothelial cells. Here, we tested the hypothesis that coupling factor 6 is present on the cell surface and is involved in the regulation of systemic ...
Wold L E - - 2001
Diabetes and hypertension both produce myocardial dysfunction that accelerates cardiovascular morbidity and mortality. Coexistence of the two often results in a more severe cardiomyopathy than either process alone. The purpose of this study was to characterize the contractile function of diabetic hypertensive cardiomyopathy at the single myocyte level. Adult spontaneously ...
Overcast J D - - 2001
The pharmacology of selenium is of much interest because selenium deficiency has been linked to cardiovascular diseases, cancer, and arthritis, and selenoenzymes are critical cellular antioxidants. We have previously reported that phenyl-2-aminoethylselenide (PAESe) and its derivatives represent a novel class of selenium-based antihypertensive agents that exhibit unique biochemical and pharmacologic ...
Takai S - - 2001
It remains to be clarified whether ACE Inhibitors extend the lifespan in cases of severe hypertension. In the present study, we examined whether inhibition of angiotensin-converting enzyme (ACE) would affect mortality in a very severe hypertensive model. Twelve-week-old stroke-prone spontaneously hypertensive rats (SHR-SP) and Wistar-Kyoto rats (WKY) were used, and ...
Kett M M - - 2001
OBJECTIVE: To characterize the in vivo vascular properties of the spontaneously hypertensive rat (SHR) renal vascular bed by examining vascular conductance/resistance responsiveness to vasoactive agents in vivo and determining whether the filtration surface area of glomerular capillaries is reduced. DESIGN AND METHODS: in vivo renal blood flow responses to intrarenally ...
Guan Y - - 2001
In order to investigate the effects of antihypertensive drugs on blood pressure and gamma-amino butyric acid (GABA) content in the hypothalamus and the possible relationship between blood pressure decrease and GABA content changes, blood pressure and GABA contents after chronic (20 weeks) treatments of nitrendipine, atenolol, captopril, hydrochlorothiazide, dihydralazine and ...
Paull J R - - 2001
It is generally accepted that short-term (4 weeks) inhibition of the renin-angiotensin system (RAS) of young spontaneously hypertensive rats (SHR) in their prehypertensive phase confers long-lasting protection from fully hypertensive levels in adulthood. However, there is very little data pertaining to the effects of such treatment in adult SHR with ...
Mujumdar V S - - 2001
Previous studies demonstrated that transition from compensatory pressure overload hypertrophy to decompensatory volume overload heart failure is associated with decreased cardiac tensile strength and activation of matrix metalloproteinase (MMP) in spontaneously hypertensive rat (SHR). To test the hypothesis that in the absence of nitric oxide activation of MMP during cardiac ...
Mokuno S - - 2001
In the current study, we investigated the NO-generation pathway in response to mechanical stimuli in SHR at the prehypertensive stage. To examine the role of NO in coronary autoregulation, we evaluated the effects of L-NAME on the coronary flow in SHR at both the prehypertensive and hypertensive stages. Isolated perfused ...
Köhler R R Department of Nephrology, University Hospital Benjamin Franklin, Freie Universität Berlin, - - 2001
The pressure-activated cation channel (PAC), a novel type of mechanosensitive channel, has been suggested to act as a mechanosensor in aortic endothelium. In experimental hypertension, PAC function was up-regulated in the established phase of high blood pressure. This association of altered PAC function and elevated arterial pressure suggests that PAC ...
Makulska-Nowak H E - - 2001
The effects of intracerebroventricular (icv) administration of endomorphin-2 (E2) on arterial blood pressure and pain threshold in spontaneously hypertensive rats (SHR) and modification of these effects by K [OP2] and mu [OP3] opioid receptors antagonists were investigated. Endomorphin-2 administrated icv in doses of 8, 16 and 32 mcg produced dose-dependent ...
Eyal S - - 2001
Hypertension is a very frequent disease, known to trigger a range of severe cardiovascular problems. The elucidation of its pathophysiology requires investigation of the mechanisms responsible for the maintenance of blood pressure in the normal system, and their possible failure in hypertension. Some of these control mechanisms display nonlinear features, ...
Sabbatini M - - 2001
Hypertension is the main cause of stroke that represents the second most common cause of death in the industrialized world and a leading cause of inability of the elderly. Lowering blood pressure reduces cerebrovascular morbidity and mortality, but it is still controversial if blood pressure should be lowered in elderly ...
Carlson S H - - 2001
The central and peripheral nervous system is typically considered to be a short-term modifier of sympathetic nervous system activity, but several lines of evidence suggest that they contribute to chronic elevation of arterial pressure in at least some forms of hypertension. Our studies focus on the mechanisms underlying NaCl-sensitive hypertension ...
Nagaya N - - 2001
To investigate hemodynamic and hormonal effects of ghrelin, a novel growth hormone (GH)-releasing peptide, we gave six healthy men an intravenous bolus of human ghrelin (10 microg/kg) or placebo and vice versa 1-2 wk apart in a randomized fashion. Ghrelin elicited a marked increase in circulating GH (15-fold). The elevation ...
Guarino N - - 2001
PURPOSE: The form and function of the heart are the final result of an integration of cells, tissues, and extracellular material. The extracellular matrix (ECM) is a complex array of different molecular components, and it plays an important role for the transfer of mechanical force in both contraction and relaxation ...
Khokhlova O N - - 2001
Local injection of 4 nmol moxonidine (unilaterally) into the rostroventrolateral medulla of spontaneously hypertensive rats (SHR-SP) decreased mean blood pressure and heart rate by 24+/-3 and 3+/-4%, respectively. Pretreatment with the I1/alpha2-receptor antagonist efaroxan abolished the moxonidine-induced decrease in mean blood pressure, but had no effect on heart rate. Yohimbine ...
Welch W J - - 2001
The tubuloglomerular feedback (TGF) responses of the spontaneously hypertensive rat (SHR) are under exaggerated regulation by angiotensin II (Ang II) type 1 receptors (AT1-R). Since AT1-Rs enhance oxygen radical (O2-) generation, we tested the hypothesis that the exaggerated TGF was due to a diminished blunting by macula densa (MD)-derived nitric ...
Taylor B K - - 2001
Many studies indicate that blood pressure control systems can attenuate pain (hypoalgesia) of short duration; however, we recently found exaggerated nociceptive responses (hyperalgesia) of persistent duration in the spontaneously hypertensive rat (SHR). Here, we used SHR, Dahl Salt-Sensitive (SS), and normotensive control rats to evaluate the contribution of sustained elevations ...
Supowit S C - - 2001
Calcitonin gene-related peptide (CGRP) expression is markedly reduced in dorsal root ganglia neurons in the spontaneously hypertensive rat (SHR). This decrease in such a potent vasodilator may contribute to the elevated blood pressure. Therefore, the purpose of this study was to determine whether stimulation of neuronal CGRP expression in SHR, ...
Hamilton C A - - 2001
There is evidence in humans that hypertension and aging similarly impair endothelial function, although the mechanism remains unclear. Superoxide anion (O(2)(-)) is a major determinant of nitric oxide (NO) bioavailability and thus endothelial function. We sought to determine the relationship between endothelial function, O(2)(-), and age in normotensive Wistar-Kyoto (WKY) ...
Vasdev S - - 2001
In spontaneously hypertensive rats (SHRs) excess endogenous aldehydes bind sulfhydryl groups of membrane proteins, altering membrane Ca2+ channels and increasing cytosolic free calcium and blood pressure. The thiol compound, N-acetyl cysteine, normalizes elevated blood pressure in SHRs by binding excess endogenous aldehydes. Vitamin C can increase tissue cysteine and glutathione ...
Verhagen A M - - 2001
Chronic nitric oxide (NO) synthase (NOS) inhibition results in renal injury. Hypertension is an important risk factor for renal injury. We studied the influence of preexistent hypertension on the sensitivity for renal injury induced by chronic NOS inhibition in rats. Spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were treated ...
Tipnis U R - - 2001
Polyamines (putrescine, spermidine and spermine) play an important role in the development of hypertension and in the expression of atrial natriuretic peptide (ANP), a cardiac hormone involved in the regulation of blood pressure. Wistar Kyoto normotensive (WKY) and spontaneously hypertensive rats (SHR) were given spermine in drinking water (0.5%) for ...
Wang M H - - 2001
The cytochrome P-450 4A (CYP4A)-derived arachidonic acid metabolite 20-hydroxyeicosatetraenoic acid (20-HETE) affects renal tubular and vascular functions and has been implicated in the control of arterial pressure. We examined the effect of antisense oligonucleotide (ODN) to CYP4A1, the low K(m) arachidonic acid omega-hydroxylating isoform, on vascular 20-HETE synthesis, vascular reactivity, ...
Paull Jeremy R. A. - - 2001
-The present study investigated the pharmacodynamic contribution of AT(1) receptor blockade to the regional hemodynamic effects of long-term treatment with the AT(1) receptor antagonist candesartan cilexetil in adult spontaneously hypertensive rats (SHR). Blood pressure and Doppler flowmetry measurements were made during and after withdrawal of candesartan cilexetil, representing times of ...
Yu Z - - 2000
The cytochrome P450-derived epoxyeicosatrienoic acids (EETs) have potent effects on renal vascular reactivity and tubular sodium and water transport; however, the role of these eicosanoids in the pathogenesis of hypertension is controversial. The current study examined the hydrolysis of the EETs to the corresponding dihydroxyeicosatrienoic acids (DHETs) as a mechanism ...
Amaral S L - - 2000
OBJECTIVE: To investigate mechanisms underlying the training-induced blood pressure-lowering effect we analyzed the hemodynamic responses and morphometric changes of the skeletal muscle microcirculation of spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats during an exercise training program. DESIGN TRAINING: (50-60% VO2 max) was performed on a treadmill for 13 weeks ...
Tanabe A - - 2000
Although evidence has been accumulated to support a role of endothelin-1 (ET-1) in cardiac hypertrophy, details of the pathophysiological significance of ET-1 in cardiac hypertrophy remain to be elucidated. In the present study, we investigated the effects of the vasodilator hydralazine on the blood pressure, cardiac hypertrophy and ET-1 gene ...
Wallen W J - - 2000
Echocardiographic studies suggest that women appear to exhibit a greater degree of myocardial hypertrophy in response to increased afterload than men. Therefore, gender differences and the role of estrogen and testosterone in the development of myocardial hypertrophy were studied in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Male ...
Hixon M L - - 2000
Vascular smooth muscle cells (VSMCs) at capacitance arteries of hypertensive individuals and animals undergo marked age- and blood pressure-dependent polyploidization and hypertrophy. We show here that VSMCs at capacitance arteries of rat models of hypertension display high levels of Akt1/PKB protein and activity. Gene transfer of Akt1 to VSMCs isolated ...
Cicogna A C - - 2000
BACKGROUND: The effect of food restriction (FR) on myocardial performance has been studied in normal hearts. Few experiments analyzed the effects of undernutrition on hearts subjected to cardiac overload. The aim of this study was to determine whether chronic FR promotes more significant changes in hypertrophied hearts than in normal ...
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