Cardiac Contractile Reserve in Spontaneously Hypertensive Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 365s-368s ◽  
Author(s):  
M. A. Saragoca ◽  
R. C. Tarazi
Keyword(s):  
Relaxation Rate ◽  
Spontaneously Hypertensive Rats ◽  
Wistar Rats ◽  
Left Ventricular ◽  
Contractile Reserve ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Ventricular Relaxation ◽  
Cardiac Contractile ◽  
Response To Stress

1. In response to graded infusions of isoprenaline, adult spontaneously hypertensive rats (20-24 weeks old) showed diminished responses of left ventricular contractile indices, diminished chronotropic responses and impairment of left ventricular relaxation rate as compared with matched Kyoto-Wistar rats. 2. These findings suggest reduced capacity to increase contractility in response to stress.

Ranolazine improves diastolic function in spontaneously hypertensive rats

2014 ◽  
Vol 306 (6) ◽  
pp. H867-H881 ◽  
Author(s):  
Sarah Williams ◽  
Marc Pourrier ◽  
Donald McAfee ◽  
Shunping Lin ◽  
David Fedida
Keyword(s):  
Diastolic Dysfunction ◽  
Diastolic Function ◽  
Spontaneously Hypertensive Rats ◽  
Heart Function ◽  
Sodium Current ◽  
Left Ventricular ◽  
Hypertensive Rats ◽  
Late Sodium Current ◽  
Spontaneously Hypertensive ◽  
Ventricular Relaxation

Diastolic dysfunction can lead to heart failure with preserved ejection fraction, for which there is no effective therapeutic. Ranolazine has been reported to reduce diastolic dysfunction, but the specific mechanisms of action are unclear. The effect of ranolazine on diastolic function was examined in spontaneously hypertensive rats (SHRs), where left ventricular relaxation is impaired and stiffness increased. The objective of this study was to determine whether ranolazine improves diastolic function in SHRs and identify the mechanism(s) by which improvement is achieved. Specifically, to test the hypothesis that ranolazine, by inhibiting late sodium current, reduces Ca2+ overload and promotes ventricular relaxation and reduction in diastolic stiffness, the effects of ranolazine or vehicle on heart function and the response to dobutamine challenge were evaluated in aged male SHRs and Wistar-Kyoto rats by echocardiography and pressure-volume loop analysis. The effects of ranolazine and the more specific sodium channel inhibitor tetrodotoxin were determined on the late sodium current, sarcomere length, and intracellular calcium in isolated cardiomyocytes. Ranolazine reduced the end-diastolic pressure-volume relationship slope and improved diastolic function during dobutamine challenge in the SHR. Ranolazine and tetrodotoxin also enhanced cardiomyocyte relaxation and reduced myoplasmic free Ca2+ during diastole at high-stimulus rates in the SHR. The density of the late sodium current was elevated in SHRs. In conclusion, ranolazine was effective in reducing diastolic dysfunction in the SHR. Its mechanism of action, at least in part, is consistent with inhibition of the increased late sodium current in the SHR leading to reduced Ca2+ overload.

Haemodynamic and Neurohumoral Changes in Spontaneously Hypertensive Rats with Aortocaval Fistulae

1993 ◽  
Vol 84 (5) ◽  
pp. 531-535 ◽  
Author(s):  
Tamiko Oka ◽  
Hikaru Nishimura ◽  
Masakuni Ueyama ◽  
Jiro Kubota ◽  
Keishiro Kawamura
Keyword(s):  
Heart Failure ◽  
Spontaneously Hypertensive Rats ◽  
Wistar Rats ◽  
Left Ventricular ◽  
Heart Weight ◽  
Stroke Index ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
High Output Heart Failure ◽  
High Output

1. Our aim was to evaluate the effects of an aortocaval fistula (1 mm) on cardiorenal haemodynamics, cardiac hypertrophy and neurohumoral factors in spontaneously hypertensive rats and to compare the results with those observed in Wistar rats at 2 weeks after fistulae placement. Sham-operated spontaneously hypertensive rats and Wistar rats served as controls. 2. Heart weight was significantly increased in spontaneously hypertensive rats (34%) and in Wistar rats (43%) at 2 weeks after fistula creation. Left ventricular systolic pressure and dp/dtmax. were significantly decreased (both P <0.01) in spontaneously hypertensive rats with fistulae which had higher left ventricular end-diastolic pressure than Wistar rats with fistulae (P <0.01). Signs of circulatory congestion (ascites, tachypnoea, prostration) were observed only in the overloaded spontaneously hypertensive rats (45%). Cardiac index was comparably increased in both fistulae groups due to an increase in stroke index, since heart rate was not increased. 3. Fistulae placement decreased renal blood flow and kidney weight, and increased blood urea nitrogen to a greater degree in spontaneously hypertensive rats (all P <0.05); serum creatinine levels were unaltered. Plasma noradrenaline concentration was increased in spontaneously hypertensive rats with fistulae (P <0.05), whereas plasma renin activity was not changed. 4. Thus, spontaneously hypertensive rats with fistulae developed overt haemodynamic signs of high-output heart failure with frequent ascites and dyspnoea, whereas most of these findings were milder or absent in Wistar rats. This model provides an opportunity to evaluate the pathophysiological and pharmacological responses in high-output heart failure.

scholarly journals Hyperbaric Oxygen Preconditioning Upregulates Heme OxyGenase-1 and Anti-Apoptotic Bcl-2 Protein Expression in Spontaneously Hypertensive Rats with Induced Postischemic Acute Kidney Injury

2021 ◽  
Vol 22 (3) ◽  
pp. 1382
Author(s):  
Jelena Nesovic Ostojic ◽  
Milan Ivanov ◽  
Nevena Mihailovic-Stanojevic ◽  
Danijela Karanovic ◽  
Sanjin Kovacevic ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Protein Expression ◽  
Hyperbaric Oxygen ◽  
Heme Oxygenase ◽  
Spontaneously Hypertensive Rats ◽  
Wistar Rats ◽  
Kidney Injury ◽  
Heme Oxygenase 1 ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive

Renal ischemia and reperfusion (I/R) injury is the most common cause of acute kidney injury (AKI). Pathogenesis of postischemic AKI involves hemodynamic changes, oxidative stress, inflammation process, calcium ion overloading, apoptosis and necrosis. Up to date, therapeutic approaches to treat AKI are extremely limited. Thus, the aim of this study was to evaluate the effects of hyperbaric oxygen (HBO) preconditioning on citoprotective enzyme, heme oxygenase-1 (HO-1), pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins expression, in postischemic AKI induced in normotensive Wistar and spontaneously hypertensive rats (SHR). The animals were randomly divided into six experimental groups: SHAM-operated Wistar rats (W-SHAM), Wistar rats with induced postischemic AKI (W-AKI) and Wistar group with HBO preconditioning before AKI induction (W-AKI + HBO). On the other hand, SHR rats were also divided into same three groups: SHR-SHAM, SHR-AKI and SHR-AKI + HBO. We demonstrated that HBO preconditioning upregulated HO-1 and anti-apoptotic Bcl-2 protein expression, in both Wistar and SH rats. In addition, HBO preconditioning improved glomerular filtration rate, supporting by significant increase in creatinine, urea and phosphate clearances in both rat strains. Considering our results, we can also say that even in hypertensive conditions, we can expect protective effects of HBO preconditioning in experimental model of AKI.

Abstract 408: Thioredoxin-1 Gene Delivery Induces Hemeoxygenase-1 Mediated Myocardial Preservation after Chronic Infarction in Spontaneously Hypertensive Rats

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
SureshVarma Penumathsa ◽  
Srikanth Koneru ◽  
Mahesh Thirunavukkarasu ◽  
Lijun Zhan ◽  
Nilanjana Maulik
Keyword(s):  
Left Ventricle ◽  
Western Blot ◽  
Infarct Size ◽  
Blot Analysis ◽  
Spontaneously Hypertensive Rats ◽  
Left Ventricular ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Thioredoxin 1 ◽  
Lac Z

Hypertension the major risk factor for many cardiovascular diseases is a result of multiple causes along with excessive generation of reactive oxygen species resulting in imbalance of redox status. Thioredoxin-1 (Trx-1) is a redox regulatory multifunctional protein with anti-inflammatory, anti-apoptotic and antioxidant effects. In the present study we investigated the therapeutic potential of Adeno-Trx-1 in spontaneously hypertensive rats (SHR). The rats were assigned to four different groups (n = 24) such as (1) normotensive Wistar Kyoto (WKY) (2) SHR (3) SHR +Adeno-Lac-Z (SHRLac-Z) and (4) SHR +Adeno-Trx-1 (SHRTrx-1). Echo-guided gene delivery to the anterior wall of left ventricle was performed using 1x109 pfu of adenovirus constructed with Trx-1 and Lac-Z. Two days after injection of adeno virus, the hearts were subjected to permanent left anterior descending coronary artery occlusion (MI). Left ventricular functions by Echocardiography were examined after 30 days of MI as the significant changes in left ventricle were observed after 4 weeks of MI. Decreased left ventricular inner diameter (7 vs 9 mm) and increased ejection fraction (52 vs 42 %), fractional shortening (28 vs 22 %) was observed in SHRTrx-1 compared to SHR. Infarct size, cardiomyocyte apoptosis and protein expression profiles (by Confocal and Western blot analysis) were observed at predetermined time points i.e after 24 and 48 hours of MI respectively. Decreased infarct size (52% vs 67%), cardiomyocyte apoptosis by TUNEL assay (161 vs 240) and increased expression of Trx-1 and HO-1 were observed in SHRTrx-1 compared to SHR. Confocal results were also confirmed by Western blot analysis. Results documented increased expression of Trx-1 (1.8 fold) and HO-1 (1.4 fold) in SHRTrx-1 as compared to SHR. In addition, we have also observed increased expression of anti-apoptotic protein Bcl-2 (1.7 fold) in SHRTrx-1 treated group compared SHR. Thus our results demonstrate for the first time that the cardioprotective effect of Adeno-Trx-1 therapy in SHR is Trx-1/HO-1/Bcl-2 mediated and may represent a novel mechanism for therapy against hypertension induced post infarction heart failure.

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