Baroreflex Sensitivity Changes during the Development of Goldblatt Two-Kidney One-Clip Hypertension in Rats

1980 ◽  
Vol 59 (5) ◽  
pp. 347-352 ◽  
Author(s):  
J. V. Jones ◽  
J. S. Floras
Keyword(s):  
Renovascular Hypertension ◽  
Time Course ◽  
Baroreflex Sensitivity ◽  
Left Ventricular ◽  
Control Group ◽  
Internal Diameter ◽  
Hypertensive Rats ◽  
Male Wistar Rats ◽  
Baroreceptor Reflex Sensitivity ◽  
Sensitivity Changes

1. The time course of changes in baroreceptor reflex sensitivity during the development of renovascular hypertension was studied in male Wistar rats in which the left renal arteries were constricted by silver wire clips of 0.18 mm internal diameter. 2. Groups of animals were studied at 3, 7, 14 and 25 days after induction of renovascular hypertension. Rats of comparable ages were included as controls. There was a significant decrease in mean baroreflex sensitivity from 0.950 ± 0.157 ms/mmHg (n = 8) in the normal control group to 0.537 ± 0.105 ms/mmHg (n = 8) in the 3 day hypertensive group (P < 0.05). Baroreflex sensitivity in the 3 day hypertensive rats was independent of the level of arterial pressure achieved in individual animals. 3. These changes in baroreflex sensitivity at 3 days precede the development of left ventricular hypertrophy and, as previously shown in this model, also precede structural vascular adaptation and resetting of the carotid sinus baroreceptor threshold. 4. A further loss of baroreflex sensitivity, which may be structurally based, occurred later. Baroreflex sensitivity in the 14 day hypertensive rats fell to 0.182 ± 0.039 ms/mmHg (n = 8) compared with the 3 day hypertensive rats (P < 0.01).

Effects of hydralazine on blood pressure, pressor mechanisms, and cardiac hypertrophy in two-kidney, one-clip hypertensive rats

1986 ◽  
Vol 64 (12) ◽  
pp. 1528-1534 ◽  
Author(s):  
James Tsoporis ◽  
Frans H. H. Leenen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Time Course ◽  
Antihypertensive Effect ◽  
Plasma Catecholamines ◽  
Left Ventricular ◽  
Prolonged Treatment ◽  
Internal Diameter ◽  
Hypertensive Rats ◽  
Blood Volumes

In 2-kidney, 1-clip hypertensive rats, the time course of changes in blood pressure (BP), heart rate, activity of the sympathetic nervous system and the renin–angiotensin system, plasma and blood volumes, left ventricular (LV) and right ventricular (RV) weight, and LV dimensions were evaluated during treatment with hydralazine 80 and 120 mg/L drinking water for 2 days or 1, 2, 3, 5, and 8 weeks. Hydralazine induced initially a clear antihypertensive effect (mean BP from 170–180 down to 135–145 mmHg (1 mmHg = 133.32 Pa)), subsequently tolerance developed. Heart rate, plasma catecholamines, and the blood pressure response to hexamethonium were not affected by treatment. Significant increases in plasma renin activity occurred during the initial 1–3 weeks of treatment. Plasma and blood volumes showed only small increases with prolonged treatment. RV weight and LV internal diameter showed significant increases at 3, 5, and 8 weeks of treatment, LV weight at 5 and 8 weeks. LV wall thickness did not change significantly. Thus, treatment with the arterial vasodilator hydralazine causes both RV hypertrophy and eccentric LV hypertrophy. Intravascular volume expansion, associated possibly with redistribution of blood volume to the central compartment, may play a major role in these cardiac effects. Increased renin release but not a generalized increase in sympathetic tone may play a role in the development of tolerance to the antihypertensive effect.

Role of sympathetic nerves during developing cardiac hypertrophy in Grollman hypertensive rats

1987 ◽  
Vol 253 (4) ◽  
pp. H818-H825
Author(s):  
R. J. Tomanek ◽  
D. W. Carlson ◽  
P. J. Palmer ◽  
R. K. Bhatnagar
Keyword(s):  
Cardiac Hypertrophy ◽  
Renovascular Hypertension ◽  
Volume Expansion ◽  
Peripheral Resistance ◽  
Sympathetic Nerves ◽  
Left Ventricular ◽  
Lv Function ◽  
Hypertensive Rats ◽  
Anterior Portion ◽  
Mitochondrial Volume

Peak left ventricular (LV) function, during rapid volume expansion, and cardiocyte structure were studied in rats with developing cardiac hypertrophy in response to Grollman hypertension (1 kidney, 1 figure 8) after chemical sympathectomy with 6-hydroxydopamine. This form of renovascular hypertension led to the same magnitude of hypertrophy in rats with or without sympathectomy. Indices of peak LV function, measured during acute volume expansion, tended to be normal or slightly higher in hypertensive rats than in controls. Sympathectomy in rats with hypertension significantly improved cardiac and stroke indices while decreasing total peripheral resistance at peak cardiac output. Despite similar magnitudes of LV hypertrophy (LVH) in the two hypertensive groups, cardiocytes in sympathectomized rats had higher mitochondrial volume densities and slightly lower myofibrillar volume densities. After regional sympathectomy of the anterior portion of the LV with phenol, mitochondrial volume density increased by 21% in hypertensive rats with LVH. These data indicate that, during the development of LVH in response to renovascular hypertension, sympathetic nerves do not contribute to the magnitude of LVH but may limit improvement in peak LV performance in response to increased preload. However, sympathetic nerves do play a role in the regulation of mitochondrial and myofibril growth.

scholarly journals Valsartan Reduces Left Ventricular Hypertrophy in Ovariectomized Spontaneous Hypertensive Rats

2020 ◽  
Vol 33 (4) ◽  
pp. 371-371
Author(s):  
Hong Ding ◽  
Ning-ying Li ◽  
Xiang Zhang ◽  
Pan-pan Zhang ◽  
Jing Yu
Keyword(s):  
Oxidative Stress ◽  
Wall Thickness ◽  
Interventricular Septum ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Ovariectomized Rats ◽  
Control Group ◽  
Hypertensive Rats ◽  
Sham Control ◽  
Ovx Rats

Abstract Objective To investigate the effects of valsartan on left ventricular mass, function, and oxidative stress in ovariectomized spontaneous hypertensive rats (SHR). Methods Twelve-week-old female SHRs were randomly divided into ovariectomy (OVX) control (n = 12), OVX + valsartan (n = 12), sham control (Sham, n = 13), and Sham + valsartan (n = 14) groups. Valsartan (30 mg/kg/day) or double-distilled water was given by oral gavage. After 12 weeks of valsartan or water treatment, left ventricular wall thickness and function, superoxide dismutase (SOD), glutathione peroxidase (GSH), and 8-hydroxydeoxyguanosine (8-OHdG) were assessed. Results There was a significant interaction between ovariectomy and valsartan on interventricular end-diastolic septum thickness (IVSTd), end-systolic interventricular septum thickness (IVSTs), left ventricular end-diastolic posterior wall thickness (LVPWTd), and left ventricular end diastolic diameter (LVEDD) (P &lt; 0.05). Valsartan treatment in OVX rats decreased IVSTd, IVSTs, LVPWTd, and LVPWTs compared to OVX control (P &lt; 0.05). Compared with Sham + control group, LVESP and ±dP/dt of LV were decreased while LVEDP was increased in OVX + control group (all P &lt; 0.05). After valsartan treatment, LVESP and ±dP/dt of LV were increased and LVEDP was decreased in ovariectomized rats (all P &lt; 0.05). Ovariectomy decreased GSH and SOD levels and increased 8-OHdG levels, which were reversed by valsartan treatment (all P &lt; 0.05). Conclusion Valsartan treatment decreases oxidative stress, reduces LV hypertrophy, and improves cardiac function in overiectomized SHR.

Beneficial effect of simvastatin and pravastatin treatment on adverse cardiac remodelling and glomeruli loss in spontaneously hypertensive rats

2005 ◽  
Vol 108 (4) ◽  
pp. 349-355 ◽  
Author(s):  
Daniele G. BEZERRA ◽  
Carlos A. MANDARIM-de-LACERDA
Keyword(s):  
Left Ventricle ◽  
Spontaneously Hypertensive Rats ◽  
Renal Cortex ◽  
Interstitial Fibrosis ◽  
Treated Group ◽  
Left Ventricular ◽  
Control Group ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Significant Difference

The aim of the present study was to investigate the possibility of different effects of the hydrophobic statin simvastatin and the hydrophilic statin pravastatin on the remodelling process in the overloaded left ventricle and renal cortex of SHRs (spontaneously hypertensive rats). Fifteen SHRs were treated for 40 days with simvastatin, pravastatin or placebo (water) via orogastric administration. Left ventricle and renal cortex were examined by light microscopy and stereology. LV (left ventricular) cardiomyocyte nuclei (N[cmn]) and glomeruli (N[gl]) numbers were estimated by the dissector method. BP (blood pressure) and serum triacylglycerols (triglycerides) were lower in the statin-treated groups than in the untreated control group. The volume density of the interstitial connective tissue was smaller and length density of the intramyocardial arteries, as well as the arteries/cardiomyocyte ratio, was greater in the statin-treated groups than in the control group. No difference was observed between the two statin-treated groups. The cross-sectional cardiomyocyte area was significantly smaller in the simvastatin-treated group than in the control or pravastatin-treated groups, and it was smaller in the pravastatin-treated group than in the control group. N[cmn] and N[gl] were greater in the two statin-treated groups than in the control group, but no significant difference was observed between the two statin-treated groups. In conclusion, administration of the statins simvastatin and pravastatin to SHRs effectively prevented the elevation in BP and serum triaclyglycerols, and also attenuated adverse cardiac and kidney remodelling by preventing LV hypertrophy, enhancing myocardial vascularization with the decrease in interstitial fibrosis and attenuating cardiomyocyte and glomerular loss.

scholarly journals l-Arginine attenuates cardiovascular impairment in DOCA-salt hypertensive rats

2005 ◽  
Vol 289 (4) ◽  
pp. H1408-H1416 ◽  
Author(s):  
Andrew Fenning ◽  
Glenn Harrison ◽  
Roselyn Rose’meyer ◽  
Andrew Hoey ◽  
Lindsay Brown
Keyword(s):  
Blood Vessels ◽  
Chronic Administration ◽  
Normal Function ◽  
Left Ventricular ◽  
Internal Diameter ◽  
Hypertensive Rats ◽  
Functional Changes ◽  
Isolated Hearts ◽  
Ventricular Wall Thickness ◽  
And Function

Nitric oxide (NO) is essential for normal function of the cardiovascular system. This study has determined whether chronic administration of l-arginine, the biological precursor of NO, attenuates the development of structural and functional changes in hearts and blood vessels of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Uninephrectomized rats treated with DOCA (25 mg every 4th day sc) and 1% NaCl in the drinking water for 4 wk were treated with l-arginine (5% in food, 3.4 ± 0.3 g·kg body wt−1·day−1). Changes in cardiovascular structure and function were determined by echocardiography, microelectrode studies, histology, and studies in isolated hearts and thoracic aortic rings. DOCA-salt hypertensive rats developed hypertension, left ventricular hypertrophy with increased left ventricular wall thickness and decreased ventricular internal diameter, increased inflammatory cell infiltration, increased ventricular interstitial and perivascular collagen deposition, increased passive diastolic stiffness, prolonged action potential duration, increased oxidative stress, and inability to increase purine efflux in response to an increased workload. l-Arginine markedly attenuated or prevented these changes and also normalized the reduced efficacy of norepinephrine and acetylcholine in isolated thoracic aortic rings of DOCA-salt hypertensive rats. This study suggests that a functional NO deficit in blood vessels and heart due to decreased NO synthase activity or increased release of reactive oxygen species such as superoxide may be a key change initiating many aspects of the cardiovascular impairment observed in DOCA-salt hypertensive rats. These changes can be prevented or attenuated by administration of l-arginine.

scholarly journals Pressure Overload Selectively Increases n-3 PUFA in Myocardial Phospholipids During Early Postnatal Period

2012 ◽  
pp. S155-S163
Author(s):  
F. NOVÁK ◽  
F. KOLÁŘ ◽  
Š. VOCŮ ◽  
M. VECKA ◽  
O. NOVÁKOVÁ
Keyword(s):  
Time Course ◽  
Ventricular Myocytes ◽  
Pressure Overload ◽  
Postnatal Period ◽  
Left Ventricular ◽  
Early Postnatal Development ◽  
Abdominal Aortic ◽  
Male Wistar Rats ◽  
Accelerated Growth ◽  
Striking Effect

Increasing hemodynamic load during early postnatal development leads to rapid growth of the left ventricular (LV) myocardium, which is associated with membrane phospholipid (PL) remodeling characterized by n-3 polyunsaturated fatty acids (PUFA) accumulation. The aim of this study was to examine the influence of additional workload imposed early after birth when ventricular myocytes are still able to proliferate. Male Wistar rats were subjected to abdominal aortic constriction (AC) at postnatal day 2. Concentrations of PL and their fatty acid (FA) profiles in the LV were analyzed in AC, sham-operated (SO) and intact animals on postnatal days 2 (intact only), 5 and 10. AC resulted in LV enlargement by 22 % and 67 % at days 5 and 10, respectively, compared with age-matched SO littermates. Concentrations of phosphatidylcholine, cardiolipin, phosphatidylinositol, phosphatidylethanolamine, phosphatidylserine and sphingomyelin decreased in AC myocardium, albeit with different time course and extent. The main effect of AC on FA remodeling consisted in the accumulation of n-3 PUFA in PL. The most striking effect of AC on FA composition was observed in phosphatidylinositol and cardiolipin. We conclude that excess workload imposed by AC inhibited the normal postnatal increase of PL concentration while further potentiating the accumulation of n-3 PUFA as an adaptive response of the developing myocardium to accelerated growth.

scholarly journals Carotid Occlusion Accentuates Aortic Stenosis and Cardiac Remodeling With Preserved Systolic Function in LDL Receptor-Deficient Mice

2021 ◽  
Vol 11 ◽  
Author(s):  
Yandong Liu ◽  
Jiawei Cai ◽  
Lefeng Qu
Keyword(s):  
Aortic Stenosis ◽  
Ventricular Remodeling ◽  
Systolic Function ◽  
Ldl Receptor ◽  
Left Ventricular ◽  
Carotid Occlusion ◽  
Plaque Burden ◽  
Control Group ◽  
Internal Diameter ◽  
And Function

Background: Carotid atherosclerotic disease is associated with aortic stenosis and reduced cardiac function. The causality between carotid and cardiac pathologies is unknown. We aim to explore the effects of carotid stenosis or occlusion on cardiac pathology and function.Methods and Results: We produced carotid obstruction or stenosis in 36 atherogenic mice with 150- or 300-μm tandem surgery or sham surgery. The structure and function of the heart were assessed by histology and animal ultrasound. The 150-μm group had larger plaque burden and thicker valve leaflets in the aortic root than did the control group. Also, the two surgery groups had a thicker left ventricular posterior wall and smaller internal diameter compared with controls. Increased myocardial fibrosis was also found in the 150-μm group compared with controls, although the surgery groups had preserved systolic function compared with that of controls.Conclusions: In a mouse model, carotid occlusion accentuated the formation of aortic stenosis and promoted ventricular remodeling without impairing systolic function. Carotid atherosclerotic plaque may be a pathogenic factor for aortic stenosis and ventricular remodeling.

Adrenomedullin gene delivery attenuates renal damage and cardiac hypertrophy in Goldblatt hypertensive rats

2001 ◽  
Vol 280 (6) ◽  
pp. F964-F971 ◽  
Author(s):  
Cindy Wang ◽  
Eric Dobrzynski ◽  
Julie Chao ◽  
Lee Chao
Keyword(s):  
Blood Pressure ◽  
Gene Delivery ◽  
Renovascular Hypertension ◽  
Protective Role ◽  
Left Ventricular ◽  
Heart Weight ◽  
Glomerular Sclerosis ◽  
Lacz Gene ◽  
Hypertensive Rats ◽  
Beneficial Effects

Adrenomedullin (AM) is a potent vasodilator and natriuretic peptide that plays an important role in cardiovascular function. In this study, we employed a somatic gene delivery approach to explore its potential protective role in renovascular hypertension. A single tail vein injection of adenovirus harboring the human AM gene significantly blunted a blood pressure increase that lasted for more than 3 wk in two-kidney one-clip (2K1C) hypertensive rats. The expression of human AM mRNA was detected in the kidney, adrenal gland, heart, lung, and liver, and immunoreactive human AM was detected in the plasma and urine of 2K1C rats after human AM gene delivery. A maximal blood pressure difference of 28 mmHg was observed 10 days after AM gene delivery, compared with that in rats injected with the control virus carrying the LacZ gene. Human AM gene delivery significantly attenuated increases in the ratio of left ventricular weight to heart weight, cardiomyocyte diameter, and fibrosis in the heart, as well as glomerular sclerosis, tubular injuries, and protein casts in the kidney. The beneficial effects of AM gene delivery were accompanied by increased urinary cAMP levels, indicating activation of AM receptors. These findings provide new insights into the role of AM in renovascular hypertension and may have significance in therapeutic applications in cardiovascular diseases.

scholarly journals Comparative study of the antihypertensive effects of hexane, chloroform and methanol fractions of essential oil of Alpinia zerumbet in rats Wistar

2016 ◽  
Vol 18 (1) ◽  
pp. 113-124 ◽  
Author(s):  
G.H. CUNHA ◽  
F.V. FECHINE ◽  
F.A. FROTA BEZERRA ◽  
M.O. MORAES ◽  
E.R. SILVEIRA ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Reactivity ◽  
Antihypertensive Effect ◽  
Negative Control Group ◽  
Negative Control ◽  
Control Group ◽  
Resonance Spectroscopy ◽  
Hypertensive Rats ◽  
Male Wistar Rats ◽  
Main Components

ABSTRACT The aim of this study was to characterize components of the EOAz and its hexane (HFEOAz), chloroform (CFEOAz) and methanol (MFEOAz) fractions, and its antihypertensive effect. EOAz was extracted from leaves by hydrodistillation. Aliquot was subjected to selective desorption with silica gel column and eluted with hexane, chloroform and methanol. The components of the EOAz and fractions were analyzed by gas chromatography coupled with mass spectrometry and nuclear magnetic resonance spectroscopy of hydrogen. Experiments of vascular reactivity were performed with isolated aortic rings of male Wistar rats. Antihypertensive effect was evaluated in hypertensive rats submitted to the inhibition of synthesis of nitric oxide. Blood pressure was measured indirectly by tail plethysmography. MFEOAz showed the lowest EC50 (150.45 µg/mL), 1,8-cineole (27.81%) and terpinen-4-ol (57.35%) as main components. Single administration by nasogastric tube of EOAz, fractions and captopril significantly reduced the blood pressure of hypertensive rats, when compared to animals of the negative control group with distilled water. In conclusion, the potency of the MFEOAz was higher than that of EOAz and other fractions. The antihypertensive effect of EOAz and fractions was similar, higher than the negative control and lower than that of captopril.

Assessment of cardiac indices using M-mode echocardiography in horse with tachycardia

2019 ◽  
Vol 20 (1) ◽  
pp. 1-5
Author(s):  
Mohamed Youssef ◽  
Medhat Nassif ◽  
Sabry El-khodery ◽  
Maged El-ashker ◽  
Alshimaa Farag
Keyword(s):  
Abdominal Pain ◽  
Clinical Signs ◽  
Posterior Wall ◽  
Ventricular Volume ◽  
Left Ventricular ◽  
Control Group ◽  
Internal Diameter ◽  
Cardiac Functions ◽  
Septal Thickness ◽  
Cardiac Indices

The aim of this study was to assess the effect of tachycardia associated with abdominal pain in horse with colic on echocardiographic measurements. For this purpose, 20 horses were selected for this study; from which 10 healthy horses were randomly selected (control group), and 10 diseased horses exhibiting the clinical signs of flatulent colic referred to the hospital of Faculty of Veterinary Medicine, Mansoura University, Egypt. Cardiac functions were evaluated using M- mode echocardiography for measurement of the cardiac indices and functions. In horses with flatulent colic, there was a significant (P < 0.05) decrease in interventricular septal thickness at end- systole (IVSTs), left ventricular internal diameter at end- diastole (LVIDd), left ventricular posterior wall at end-diastole (LVPWd), stroke volume (SV), and ejection fraction (EF) compared with control group. However, there was a significant (P < 0.05) increase in left ventricular volume at end- systole (ESV) in comparison with control group. The results of the present study indicate that evaluation of cardiac indices and functions via echocardiography may be of great benefit for evaluation of clinical outcome of tachycardia associated with abdominal pain in horses.

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