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Results 701 - 750 of 1435
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Gray S D - - 1994
Three types of hypertensive rats, and their normotensive controls, were assessed to determine the effects of high blood pressure on the contractile and fatigue properties of the soleus muscle. Spontaneously hypertensive rat (SHR) soleus developed less contractile force and fatigued more rapidly than normotensive Wistar-Kyoto (WKY) controls. In contrast, normotensive ...
O'Leary D S - - 1994
Spontaneously hypertensive rats (SHR) are more suitable to heat stroke than are normotensive controls. To determine whether hypertension impairs thermoregulatory reflex cutaneous vasodilation we observed the tail skin vasodilator responses to body heating in male SHR and normotensive Wistar-Kyoto rats (WKY) anesthetized with chloralose and urethan (80 mg/kg and 500 ...
Golden A L - - 1994
The primary objectives of this study were to determine if hypertrophied spontaneously hypertensive rat (SHR) hearts exhibited a greater increase in intracellular sodium (Na+i) compared with Wistar-Kyoto (WKY) control rats during low flow ischemia, and to determine whether Na+i accumulation in these hearts was associated with greater ischemic dysfunction and ...
Boone J B JB - - 1994
Enkephalins have been discovered in various regions of the brain involved in cardiovascular regulation. Sympathoadrenal hyperactivity and altered baroreflex activity have been implicated in the development of hypertension. The purpose of this investigation was to determine whether proenkephalin gene expression is altered in the arterial baroreceptor reflex region of the ...
Calhoun D A - - 1994
We have previously reported that high dietary salt exposure significantly increases daytime mean arterial pressure in spontaneously hypertensive rats (SHR) but not in normotensive Wistar-Kyoto (WKY) controls. In the present study, we used a telemetry monitoring system to evaluate the effects of high dietary salt exposure on diurnal variation of ...
Styƛ T - - 1994
In order to find out whether the pressor effect of arginine vasopressin (AVP) is limited by release of nitric oxide (NO) and whether it is altered in hypertension, blood pressure (MAP) and heart rate (HR) responses to i.v. administration of AVP were compared in conscious normotensive Wistar Kyoto (WKY) and ...
Rusch N J - - 1994
Rat arterial muscle cells show an elevated Ca(2+)-dependent K+ efflux during the established phase of hypertension. This association of enhanced K+ efflux with high arterial pressure implies that changes of in vivo blood pressure can alter the level of K+ channel current in arterial membranes. We directly tested this hypothesis ...
Thybo N K - - 1994
Long-term treatment of young spontaneously hypertensive rats (SHR) with angiotensin-converting enzyme (ACE) inhibitors has a persistent effect on blood pressure when treatment is withdrawn. The aim of the present study was to determine whether this effect could be mediated by the effect of treatment on resistance-artery structure. We determined the ...
Jelicks L A - - 1994
We have used 23Na nuclear magnetic resonance spectroscopy to examine the relationship between intracellular sodium and cardiac muscle alterations in genetic hypertension. In the spontaneously hypertensive rat (SHR) compared with the normotensive Wistar-Kyoto rat (WKY) (aged 15 to 19 weeks), mean systolic blood pressures (measured using the tail-cuff method) were ...
Schoemaker R G - - 1994
We evaluated, firstly, the sensitivity to cardiac ischemic ATP breakdown during the development of hypertension and cardiac hypertrophy in Spontaneously Hypertensive Rats (SHR) v Wistar Kyoto (WKY) controls, and secondly, the effects of short-term (8 days) and prolonged (3 months) antihypertensive treatment with the angiotensin converting enzyme inhibitor enalapril on ...
Januszewicz A - - 1994
The aim of the study was to investigate to what extent inhibition of nitric oxide (NO) formation, cyclooxygenase and converting enzyme activities and vasopressin V1 receptors blockade affects the cardiovascular system in conscious, freely moving normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. The experiments were performed on 33 WKY ...
Wang J Q - - 1994
Previous studies by us established that dynorphin A-(1-8) concentration in the hippocampal formation of spontaneously hypertensive rat (SHR) brain was much less than in the hippocampus of normotensive controls. The connection between low dynorphins and SHR hypertension was unclear. The object of the present study was to determine (1) whether ...
van den Buuse M - - 1994
Circadian rhythms of blood pressure, heart rate, and locomotor activity were measured with implanted radio-telemetry transmitters in conscious, unrestrained spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). During the light period (0600 to 1800 h) systolic, diastolic, and mean blood pressure, heart rate, and locomotor activity were lower than during ...
Stepniakowski K - - 1994
The purpose of the present study was to compare influence of central arginine vasopressin (AVP) and of atrial natriuretic peptide (ANP) on control of arterial blood pressure (MAP) and heart rate (HR) in normotensive (WKY) and spontaneously hypertensive (SHR) rats. Three series of experiments were performed on 30 WKY and ...
Kost C K CK - - 1994
The two aims of the present study were to: 1) explore the hypothesis that the kidneys of spontaneously hypertensive rats (SHR) are more responsive to angiotensin II (Ang II) than are the kidneys of normotensive Wistar Kyoto rats (WKY) and 2) determine whether other vascular beds of SHR exhibit enhanced ...
Ellstrom D R - - 1994
Na+/H+ exchange differs kinetically in mesenteric arteries from spontaneously hypertensive rats (SHR). Both the maximal transport rate and the sensitivity to [H+]i are greater in SHR than in Wistar Kyoto (WKY) rats. Kinetic changes are not seen in prehypertensive SHR or in SHR rendered normotensive by captopril therapy. Thus, blood ...
Xie L D - - 1994
Fifty-eight spontaneously hypertensive rats (SHR) at 12 wk of age were divided into 3 groups: A) captopril (Cap) 20 mg.kg-1.d-1; B) clonidine (Clo) 30 micrograms.kg-1.d-1; C) Clo 30 micrograms.kg-1.d-1 + Cap 20 mg.kg-1.d-1 orally for 24 wk. Concomitant administration of Cap and Clo did not result in more lowering of ...
Schork N J - - 1994
Blood pressure and body weight rise with age, and hypertension is hypothesized to result from an early disorder of growth. We used the statistical technique of spline fitting to examine patterns of growth and rising blood pressure in individual inbred rats of the Wistar-Kyoto, spontaneously hypertensive (SHR), and stroke-prone SHR ...
Ohlstein E H - - 1994
The effects of carvedilol, a novel cardiovascular agent, were evaluated in developing spontaneously hypertensive rats (SHR) for effects on hemodynamics, and the ability to effect the development of left ventricular, and vascular hypertrophy associated with chronic hypertension. Chronic oral administration of low dose carvedilol (20 mg/kg/day) was initiated when rats ...
Schraeger J A - - 1994
We wished to determine whether (a) left ventricular (LV) diastolic chamber compliance and tissue elastic modulus were decreased with hypertrophy and improved after reversal of hypertension and regression of hypertrophy and whether collagen concentration was a major determinant of LV chamber compliance during hypertrophy or aging. Spontaneously hypertensive rats (SHR) ...
Januszewicz A - - 1994
The aim of the study was to investigate blood pressure responses and changes in heart rate after bolus administration of endothelin-3 [ET-3] in conscious, freely moving SHR and WKY rats and DOCA-salt hypertensive and normotensive Wistar rats. The effect of ET-3 on blood pressure and heart rats was investigated for ...
Bexis S - - 1994
In the present study, we compared the blood pressure in the SHR-SP and in the spontaneously hypertensive rat (SHR) after dietary administration of fish oil from 4 to 17 weeks of age. The retarding influence of dietary fish oils on the development of hypertension was prominent in the SHR (26 ...
Hirata Y - - 1994
OBJECTIVE: To study the possible involvement of intrarenal endothelial dysfunction in the modulation of the pressure-natriuresis curve in spontaneously hypertensive rats (SHR). METHODS: We examined the effect of endothelin on pressure natriuresis in isolated perfused kidneys from 16-week-old SHR and Wistar-Kyoto (WKY) rats. Plasma and urinary endothelin levels in intact ...
Harrap S B - - 1994
1. Brief treatment with angiotensin-converting enzyme (ACE) inhibitors in young spontaneously hypertensive rats (SHR) causes a persistent reduction in blood pressure associated with a relatively selective reduction in renal vascular resistance. 2. To study the possible role of the kidney in this long-term hypotensive effect, we transplanted kidneys from untreated ...
Vincent M - - 1994
We investigated the involvement of loci on the sex chromosomes in the hypertension of the spontaneously hypertensive rat (SHR) by studying male F1 and F2 generation rats derived from reciprocal crosses of SHR with Wistar-Kyoto (WKY) rats (cross 1: WKY female x SHR male; cross 2: SHR female x WKY ...
Rizzoni D - - 1994
The time-course of the development of vascular and cardiac hypertrophy, as well as of arterial dysfunction, in human and experimental hypertension is still unclear. Moreover, the interrelationships between structural and functional vascular alterations are presently under debate. The aim of this study was to assess the arteriolar wall thickness and ...
Benetos A - - 1994
The aim of this study was to assess life survival, and arterial and cardiac structural changes following chronic selective beta-blockade in spontaneously hypertensive rats (SHR). Twenty-two SHR aged 3 months and 20 SHR aged 18 months were treated with the beta 1-blocking agent bisoprolol (10 mg/kg/day) or placebo for a ...
Harrap S B - - 1994
1. Brief treatment with angiotensin-converting enzyme (ACE) inhibitors in young spontaneously hypertensive rats (SHR) causes a reduction in blood pressure that persists into maturity. The lifetime effects of such treatment have not been studied. 2. Nineteen male SHR were treated with either water (n = 9) or perindopril (3 mg/kg ...
Gairard A - - 1994
Several reports suggested an involvement of parathyroid function in blood pressure regulation in animals and humans: hyperparathyroid subjects frequently display an elevated systolic blood pressure and young mild hypertensive patients show enhanced serum PTH levels. Moreover, removal of parathyroid glands (PTX) in young rats attenuates and delays the development of ...
Cheng J T - - 1994
The effects of geraniin, one of the ellagitannins purified from the leaves of Sapium sebiferum, on blood pressure were investigated in the spontaneously hypertensive rat (SHR). A single intravenous bolus injection of geraniin into anaesthetized SHRs lowered the arterial mean blood pressure in a dose-dependent manner without affecting the heart ...
Vulpis V - - 1994
The ACE inhibitors cilazapril and captopril were administered at 10 and 100 mg/day, respectively, to spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats (WKY) from the 12th to the 22nd week of life. Both drugs produced statistically significant reductions in systolic and diastolic blood pressure, left-ventricular mass and index of left-ventricular ...
Ferrante F - - 1994
The purpose of this study was to ascertain if Isradipine treatment in spontaneously hypertensive rats (SHR) decreased hypertension-dependent left ventricular and coronary vascular hypertrophy. Twelve week male SHR were used in this study; one group of SHR was treated with Isradipine while the control group of SHR was left untreated. ...
Kohno I - - 1994
Blood pressure, heart rate and physical activity in spontaneously hypertensive rats (SHR) were measured and compared with those of Wistar Kyoto rats (WKY) to see how these parameters vary with age and whether we can find a marker of essential hypertension among these variables. An automatic telemetric system was employed ...
Huang C - - 1994
1. This investigation examined the autoregulatory efficiency of different vascular regions of the normotensive and stroke prone-spontaneously hypertensive rat (SP-SHR) kidney and determined how these myogenic responses were dependent upon extracellular calcium. In acute studies, renal autoregulatory blood perfusion curves for cortex and papilla were generated, autoregulatory indices (AI's) calculated ...
Nishimura H - - 1994
The effects of angiotensin-converting enzyme (ACE) inhibitors in high-output heart failure have not yet been well established. We evaluated the effects of lisinopril (3 mg/kg/day) on hemodynamics, neurohormones, and survival in 10-week-old spontaneously hypertensive rats (SHR) with aortocaval fistula. Sham-operated treated and untreated SHR served as controls. Cardiac output (CO) ...
Leenen F H - - 1994
BACKGROUND: In contrast to studies in isolated blood vessels, results from whole-animal studies are ambiguous regarding differences in pressor responsiveness between spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats, possibly related to the measurement of blood pressure instead of total peripheral resistance (TPR) and to differences in compensatory mechanisms. OBJECTIVE ...
Amrani F C - - 1994
The effects of trandolapril, a converting enzyme inhibitor (CEI), on left ventricular (LV) diastolic stiffness and coronary vascular resistance (CVR), were studied with an isolated heart preparation in 15-month-old spontaneously hypertensive rats (SHR). The hypertensive animals were treated for 3 months with trandolapril (0.3 mg/kg/day) (SHRT), and compared with untreated ...
Madeddu P - - 1994
We studied the role of brain kinins in the regulation of cardiovascular function. Intracerebroventricular injection of 380 pmol bradykinin increased mean blood pressure by 20 +/- 2 mm Hg (P < .01) in normotensive Wistar-Kyoto (WKY) rats. Complete inhibition of this effect was achieved with intracerebroventricular administration of the newly ...
Garcia G E - - 1994
Although the structure of chromogranin A (CgA) is now known, its ultimate physiological role remains elusive. Recently, an interior fragment of CgA [CgA(124-143)], also called chromostatin, was reported to suppress catecholamine release from chromaffin cells in vitro. We therefore explored chromostatin's biological actions when administered in vivo to anesthetized rodents ...
Yongue B G - - 1993
Several characteristics of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY), make these homozygous strains particularly well suited for investigating the interactions of salt appetite, blood pressure control, and their neuroendocrine substrates. Appropriate genetic and developmental investigations of sources of variation in salt appetite, blood pressure, and their putative ...
Traub O - - 1993
Studies have shown that angiotensin-converting enzyme (ACE) inhibitor treatment in young genetically hypertensive rats prevents the full expression of blood pressure and vascular abnormalities in the adult. This model provides unique conditions with which to study the pathogenesis of altered Ca++ regulation. Normotensive (WKY) rats and stroke-prone spontaneously hypertensive rats ...
Tsoporis J - - 1993
OBJECTIVE AND DESIGN: In spontaneously hypertensive rats (SHR) arterial vasodilators do not cause regression and might cause further progression of cardiac hypertrophy. To assess whether these effects extend to the vasculature, and to examine the possible mechanisms involved, cardiac and mesenteric arterial structure was evaluated with respect to changes in ...
Huang A - - 1993
To elucidate the underlying reason or reasons for the increased peripheral resistance in hypertension, we investigated the pressure-diameter relation--the myogenic response--of isolated, cannulated arterioles (approximately 50 microns) of cremaster muscle of 12-week-old Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHR), and normal Wistar (NW) rats. All arterioles constricted in response to ...
Grassi de Gende A O - - 1993
This study describes the relationship between left ventricular mass and systolic arterial pressure (SAP) in normotensive and hypertensive rats. The genetically hypertensive rats (SHR) were stratified according to their SAP values in to hypertensive (SHRH) and normotensive (SHRN) subgroups. Males and females of both subgroups exhibited biventricular hypertrophy and the ...
Vacher E - - 1993
The effects of long-term oral administration of quinapril on the occurrence of stroke and on mortality were investigated in young salt-loaded stroke-prone spontaneously hypertensive rats (SHR-SPs) during the treatment period (8th-34th week of age) and up to 6 weeks thereafter. Simultaneously, blood pressure, saline intake, diuresis, and proteinuria were investigated ...
Bukoski R D - - 1993
The effect of long-term daily injection of 1,25 (OH)2 vitamin D3 on blood pressure and contractile force generation by subsequently isolated mesenteric resistance arteries was examined using the spontaneously hypertensive rat (SHR) model of genetic hypertension. Beginning at 6 weeks of age, male SHR were given daily intraperitoneal injections of ...
Katayama S - - 1993
A study was designed to clarify the effects of captopril (CAP) or nitrendipine (NITR) on cardiac hypertrophy and left ventricular expression of the laminin B2 or collagen (COL) gene in spontaneously hypertensive rats (SHRs). Cardiac weight was significantly increased in 20-week-old SHRs. Gene expression of the alpha 1 chain of ...
Falloon B J - - 1993
To examine the function of resistance-sized arteries in hypertension under in vitro conditions that approximate in vivo conditions as much as possible, we mounted segments of second-order mesenteric resistance arteries from spontaneously hypertensive rats (SHR) and Wistar-Kyoto normotensive control rats aged 12 to 13 weeks in a perfusion myograph and ...
Engler M M - - 1993
The effects of oils enriched with gamma-linolenic acid (GLA) on blood pressure and pressor responses were examined in spontaneously hypertensive rats (SHR). Rats were fed purified diets containing evening primrose (EPO), black currant (BCO), borage (BOR) or fungal (FGO) oils for 7 weeks. Significant reductions in blood pressure were obtained ...
Cai Y - - 1993
The mechanism of hypoxic moderation of systemic systolic blood pressure was investigated in spontaneously hypertensive rats (SHR). Male SHR rats were divided into hypoxic (H, 5000 m for 15 d) and normoxic (N) groups. The systemic blood pressure of SHR-H (24.9 +/- 1.2 kPa) was found to be 3 kPa ...
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