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Results 801 - 850 of 1435
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Wåhlander H - - 1992
Myocardial capillary exchange capacity was investigated by stereologic and functional techniques in parallel during pressure-overload cardiac hypertrophy and after long-term antihypertensive therapy with the vasodilator felodipine. In 26-week-old female spontaneously hypertensive rats (SHR) blood pressure increased by 25% and left ventricular weight (LVW/BW) increased by 18% compared to Wistar-Kyoto rats ...
Friberg P - - 1992
The present study was designed to explore to what extent pressure reduction by antihypertensive therapy and pressure elevation by renal hypertension are able to affect structural vascular and cardiac changes in young spontaneously hypertensive rats (SHR). Pressure elevation in SHR was induced by means of superimposing 2 kidney, 1 clip ...
Chiu E K - - 1992
Mean arterial pressure (mmHg (1 mmHg = 133.322 Pa)), sodium excretion rate (mumol.kg-1.min-1), and urine flow (microL.kg-1.min-1) were measured in conscious unrestrained spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) before, during, and after a 3-h intravenous infusion of arginine vasopressin (20 ng.kg-1.min-1), an equipressor dose of phenylephrine, or ...
Harada S - - 1992
To investigate dynamic or frequency-dependent characteristics of arterial baroreflex control of efferent sympathetic nerve activity in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY), we assessed the transfer function from aortic pressure (AP) to renal sympathetic nerve activity (RSNA) using a "white-noise technique." In pentobarbital sodium-anesthetized rats, we recorded RSNA ...
Jin H - - 1992
Our previous studies have suggested that atrial natriuretic peptide in the caudal nucleus tractus solitarii is involved in the centrally mediated regulation of blood pressure in the salt-sensitive spontaneously hypertensive rat (SHR). The current study tested the hypothesis that endogenous atrial natriuretic peptide in the caudal nucleus tractus solitarii participates ...
Monopoli A - - 1992
SCH 34826, i.e., (S)-N-(N-(2,2[(2,2-dimethyl-1,3-dioxolan-4- yl)methoxy]-2-oxo-1-(phenyl-methyl)ethyl)-phenylalanyl)-beta-alanine, is a potent and selective inhibitor of neutral endopeptidase 24.11 (NEP), an enzyme that degrades the atrial natriuretic peptide (ANP). The effects of SCH 34826 on hypertension and left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHRs) were evaluated following 1 month of treatment by ...
Ohno A - - 1992
OBJECTIVE: Studies were undertaken to clarify the pathophysiologic significance of endogenous endothelin in the control of blood pressure and renal hemodynamics in spontaneously hypertensive rats (SHR). DESIGN: The technique of passive immunization was used to neutralize endogenous endothelin in order to estimate the contribution of endothelin to the in vivo ...
Benetos A - - 1992
AIM: To measure the mechanical properties of the rat carotid artery as affected by physiological and pharmacological changes. METHODS: We used an in situ measurement method that did not affect the anatomy, vascularization or innervation of the carotid artery, in normotensive and in spontaneously hypertensive rats (SHR), to evaluate the ...
Sen S - - 1992
INTRODUCTION: Myosin isozymes have been known to become altered during the development and regression of myocardial hypertrophy, but the mechanism by which the shifting takes place is not known. The present paper describes the effects of antihypertensive drugs, with a known mechanism of action, upon myocardial mass, blood pressure and ...
Janssen B J - - 1992
In models that describe the homeostasis of the circulation, arterial blood pressure is usually expressed as a single value, which is regarded as the set point in such systems. The aim of the study was to identify in rats from 24-h beat-to-beat recordings the value of blood pressure that describes ...
Yamashita Y - - 1992
OBJECTIVE AND DESIGN: The present study was designed to determine whether increases in sodium concentration in the cerebrospinal fluid (CSF) play a role in the augmented hypertension induced by long-term salt loading in spontaneously hypertensive rats (SHR), and whether the enhanced arginine vasopressin (AVP) activity and/or the sympathetic nervous system ...
Caputo L - - 1992
OBJECTIVE: To compare the mechanical properties of carotid arteries from normotensive and spontaneously hypertensive rats. DESIGN: The pressure-diameter relationships of carotid arteries from nine normotensive adult Wistar-Kyoto (WKY) and nine spontaneously hypertensive rats (SHR) were measured in vitro under control conditions and after poisoning the smooth muscle cells with potassium ...
Waeber B - - 1992
AIM: These studies were undertaken in intact spontaneously hypertensive rats (SHR) to assess whether the elastic behavior of conduit arteries changes as a function of age. METHODS: We studied 16-week-old (n = 10) and 36-week-old (n = 10) SHR under fluothane anesthesia. Diameter-, compliance-, and distensibility-pressure curves were established non-invasively ...
Thiel M A - - 1992
Intraluminal pressure may affect vascular contractility in both normotension and hypertension. To test this hypothesis, we studied mesenteric resistance arteries from normotensive humans as well as normotensive (WKY) and spontaneously hypertensive (SHR) rats (internal diameter 214 +/- 27, 201 +/- 6, and 172 +/- 6 microns, mean +/- SEM at ...
Head G A - - 1992
1. We have examined the baroreceptor-heart rate (HR) reflex in weight-matched conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats during development. 2. Graded steady-state changes in mean arterial pressure (MAP) and the corresponding HR responses before and after vagal blockade with methylatropine were fitted to an S-shaped logistic ...
Beilin L J - - 1992
OBJECTIVE: Clarification of the effect of chronic ethanol consumption upon cardiovascular reactivity in rats. DESIGN: Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) normotensive rats were randomly allocated in groups of 10 to ethanol in tap water [20% (v:v) after the first week or tap water for 7-12 weeks]. METHODS: Intra-arterial ...
Gaballa M A - - 1992
To characterize the interaction between mechanical and fluid transport properties in hypertension, we measured in vivo elastic material constants and hydraulic conductivity in intact segments of carotid arteries in normal and spontaneously hypertensive rats (SHR). With the use of a finite element model, the arterial wall was modeled as a ...
Hayoz D - - 1992
METHODOLOGY: A new non-invasive ultrasonic device was developed to characterize the biomechanical properties of medium and large peripheral arteries. Simultaneous recordings of internal diameter and blood pressure over the whole cardiac cycle are used to establish compliance-pressure curves. Since blood pressure, which is an inherent co-determinant of arterial compliance, is ...
Fragman S - - 1992
Adrenalectomized, spontaneously hypertensive rats (SHR) were used to test the hypertensinogenic property of recently synthesized 18,19-dihydroxycorticosterone (18,19-Di-OH-B). The steroid was given via Alzet miniosmotic pump, with and without aldosterone. Neither 18,19-Di-OH-B (5 micrograms) nor aldosterone (5 micrograms) increased blood pressure in SHR when given alone; when administered together they resulted ...
Arnolda L - - 1992
There is compelling evidence for the participation of excitatory and inhibitory amino acids in the neural regulation of blood pressure in the normotensive rat. This is most clearly evident in the neural pathways which form the baroreceptor reflex arc. Excitatory amino acids are contained in baroreceptor afferents, neurons in the ...
Fujii K - - 1992
The goal of the current study was to determine whether treatment of hypertension reduces cerebral infarction after occlusion of the middle cerebral artery in stroke-prone spontaneously hypertensive rats (SHRSPs). Three-month-old SHRSPs received untreated drinking water or drinking water containing cilazapril, an angiotensin converting enzyme inhibitor, or hydralazine and hydrochlorothiazide. After ...
Mizuno K - - 1992
MK 954 (DuP 753), a recently developed angiotensin II (Ang II) receptor antagonist, was administered orally for 2 weeks to spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY). Whereas the basal levels of plasma Ang II were lower in SHR than in WKY, treatment with MK 954 markedly reduced blood pressure ...
Paulson D J - - 1992
The purpose of the present study was to determine whether 15 weeks of dietary fish oil supplementation to Wistar Kyoto (WKY) and stroke-prone spontaneously hypertensive rats (SP-SHR) would alter cardiac contractile performance. Isolated perfused working hearts were used to determine the effects of varying left atrial filling pressures on cardiac ...
Nishimura H - - 1992
OBJECTIVE: Left ventricular function (LVF) after reversal of left ventricular hypertrophy (LVH) with antihypertensive therapy is still controversial. The present study was undertaken in spontaneously hypertensive rats (SHR) to determine whether LVF of the regressed heart with lisinopril is normally maintained. DESIGN: We compared cardiac function of SHR after reversal ...
Nordlander M - - 1992
To investigate if blood pressure reduction per se may prevent progressive renal disease in aging spontaneously hypertensive rats (SHR), 15-month-old SHR were treated with the calcium antagonist felodipine, with the beta-blocker metoprolol or with the combination for six months. The combined regimen caused the greatest blood pressure reduction over time, ...
Harrap S B - - 1992
The higher blood pressures of male compared with female spontaneously hypertensive rats (SHR) are the result of the inheritance of different sex chromosomes, although the pathophysiology has not been defined clearly. The reported hypertensive effect of kidneys transplanted from male SHR raises the possibility of a sex-specific renal abnormality, but ...
Head G A - - 1992
In the present study, we examined whether antihypertensive treatment of young and adult hypertensive rats with the angiotensin-converting enzyme (ACE) inhibitor perindopril could restore the baroreflex vagal deficit and whether this was related to prevention of cardiac or vascular hypertrophy. Spontaneously hypertensive (SHR), stroke-prone spontaneously hypertensive (SHR-SP), and Wistar-Kyoto (WKY) ...
McCarty R - - 1992
Over the past 20 years, laboratory studies of genetically defined animal models of human essential hypertension have provided valuable information on the pathophysiology of this disturbance in cardiovascular regulation. Relatively fewer studies have examined the impact of preweaning factors on the developing cardiovascular system of hypertensive animals. In our laboratory ...
Horinaka S - - 1992
OBJECTIVE: The effects of a new beta 1 adrenergic receptor blocking agent with beta 2 receptor agonistic properties on cardiovascular mass, left ventricular function, and aortic distensibility were studied in Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. METHODS: 20 male SHR and 20 male WKY rats (10 treated and 10 ...
DiPette D J - - 1992
Hypertension is often accompanied by abnormalities of calcium homeostasis, including hyperparathyroidism with reduced target organ responses to PTH in kidney and bone. Due to this association between PTH and hypertension and since PTH and the paracrine factor PTH-related protein (PTHrp) have both been shown to exert marked changes in cardiovascular ...
Chiu E K - - 1992
The importance of the autonomic nervous system (ANS) in the withdrawal-induced antihypertensive phenomenon (WAP) to arginine-vasopressin (AVP) in the spontaneously hypertensive rat (SHR) was investigated by studying the response to AVP infusion and withdrawal in the presence and absence of ganglionic blockade. In the absence of autonomic blockade, AVP infusion ...
Contreras R J - - 1992
Our prior study showed that the basal blood pressure level and pressor response to peripheral angiotensin II of adult Sprague-Dawley rats were enhanced by perinatal exposure to a high NaCl diet. The purpose of the present study was to assess further the relationship between NaCl-sensitivity of blood pressure and perinatal ...
Neves F A - - 1992
We studied the importance of genetic predisposition in the development of stress-induced hypertension in the spontaneously hypertensive rat (SHR), Wistar-Kyoto (WKY) rat, and borderline hypertensive rat (BHR; first-generation offspring of SHR and WKY). Rats were submitted to seven 72-hour sessions of rapid eye movement sleep deprivation (REM-sd) every other week ...
St Louis C - - 1992
The effects of chronic treatments of adult (aged 16-17 weeks) spontaneously hypertensive rats (SHRs) with different doses of gamma-linolenic acid (GLA) on blood pressure, heart rate, and body weight were studied. Twice-daily injection of SHRs with GLA lowered systolic blood pressure from 175 +/- 4 to 145 +/- 4 mm ...
Herrmann H J - - 1992
The existence of structural reactions of the microvasculature of spontaneously hypertensive rats (SHR) and the underlying causal mechanisms are generally controversially discussed. Ninety-two male SHR aged 3-52 weeks and 118 normotensive age and sex matched controls were investigated. A new histomorphometric procedure was applied that ascertains structural changes in microvessels ...
Ito S - - 1992
In uncomplicated essential hypertension, renal blood flow, glomerular filtration rate, and glomerular capillary pressure are within the normal range despite elevated renal perfusion pressure, suggesting abnormally high resistance of the preglomerular vessels. Among various preglomerular vascular segments, the afferent arteriole (Af-Art) is thought to be the site responsible for most ...
Amann K - - 1992
Light and electron microscopic stereological studies were performed on the myocardium of spontaneously hypertensive rats (SHR-SP) before and after treatment with nifedipine (27 mg/kg body weight/day) and the antisympathotonic agent moxonidine (8 mg/kg body weight/day). The treated groups were compared with nontreated SHR-SP and normotensive WKY (n = 10 in ...
Hayashi K - - 1992
We recently demonstrated that the interlobular artery (ILA) constricts in response to elevating renal arterial pressure (RAP), suggesting that the ILA contributes to renal autoregulation. In the present study, we examined the segmental myogenic responsiveness of the ILA in kidneys from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The ...
Singewald N - - 1992
Inactivation of GABA was inhibited by gamma-vinyl GABA (GVG) and the effects of the increased GABA level in the brain on blood pressure and body weight of spontaneously hypertensive rats (SHR) and normotensive rats (WKY) were investigated. When started at the age of 8 weeks or 5 weeks, treatment of ...
Okuda S - - 1992
The accumulation of extracellular matrix (ECM) is an important feature of most forms of progressive glomerular diseases. In order to examine the relationship between ECM synthesis and glomerulosclerosis, we evaluated fibronectin synthesis by glomeruli with the immunoprecipitation of conditioned media from isolated glomeruli in 5/6 nephrectomized spontaneously hypertensive rats (5/6N-SHR). ...
Wuorela H - - 1992
The effects of oral calcium loading on the development of hypertension were studied in spontaneously hypertensive rats (SHR). Forty-eight male SHR were divided into four groups according to treatment: control, calcium, deoxycorticosterone (DOC) and DOC + calcium. Both calcium groups received ad libitum 1.5% CaCl2 as drinking fluid. The DOC ...
Randall O S - - 1992
Invasive hemodynamic measurements were performed on 14 normotensive Wistar-Kyoto (WKY) rats and 15 spontaneously hypertensive rats (SHRs) to test the hypothesis that SHRs have lower total arterial compliance than WKY rats. Ascending aortic pressure was measured with a catheter-tip manometer, and aortic flow was measured with an electromagnetic flow probe. ...
Meldrum M J - - 1992
The potassium-induced release of 3H-norepinephrine (3H-NE) was examined in the rat caudal artery. A simple and reliable method was developed to examine stimulated neurotransmitter release from this highly innervated resistance vessel. The potassium-induced release of 3H-NE was dose- and calcium-dependent. Stimulated 3H-NE release was elevated in the spontaneously hypertensive (SHR) ...
Criscione L - - 1992
The vasoconstrictor effects of endothelin-1 were studied in perfused mesenteric vascular beds (MVB) and aortic rings of 4-week-old spontaneously hypertensive rats (SHR) and age-matched Wistar Kyoto rats (WKY). Mean blood pressure (124 +/- 4 vs. 97 +/- 3 mmHg) and initial perfusion pressure in the MVBs (25 +/- 2 vs. ...
Yoshimoto R - - 1992
Antihypertensive effects of FRC-8653, a new 1,4-dihydropyridine derivative, and its combined effects with an angiotensin converting enzyme (ACE) inhibitor, a diuretic, and a beta-adrenergic blocking agent were examined in conscious spontaneously hypertensive rats (SHR). When administered intravenously to SHR (10, 30 micrograms/kg), FRC-8653 lowered blood pressure more slowly and sustained ...
Fior D R - - 1992
The intracerebral administration of kininase inhibitors produced an increase in arterial pressure of the SHR but not in normotensive animals. The SHR were several fold more sensitive to the pressor response elicited by the intracerebral injection of bradykinin, however SHR with low blood pressure showed decreased sensitivity to the bradykinin ...
Harrap S B - - 1992
1. Certain genes drive the blood pressure of young spontaneously hypertensive rats (SHR) to stable hypertensive levels in adulthood. 2. Relatively brief blockade of the renin-angiotensin system in young SHR can reset the track of SHR pressure to a lower level for the life of the animal. This effect appears ...
Tipton C M - - 1991
Studies with male spontaneously hypertensive rats (SHR) were initiated to determine the hemodynamic relationships associated with the lower resting caudal artery systolic blood pressure (SBP) of endurance-trained SHR populations. After assignment into nontrained (NT, n = 38) and trained (T, n = 38) groups, the T animals were exercised 5 ...
Blizard D A - - 1991
We compared the ability of a high-NaCl diet to produce blood pressure elevation in spontaneously hypertensive rats (SHR) from the major North American commercial suppliers (Harlan, Taconic Farms, Charles River) and SHR and stroke-prone SHR (SHRSP) from the National Institutes of Health (NIH). Animals were raised on a low-NaCl diet ...
Korner P I - - 1991
We have recently modeled the structural factors responsible for the increased slope of the dose-vascular resistance response curves in the hindquarter bed under both in vitro and in vivo conditions. Slope increases when the ratio of wall thickness to internal radius (ri) increases and when ri decreases, but the slope ...
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