Longitudinal studies on the effect of hypertension on circadian hemodynamic and autonomic rhythms in telemetered rats

El‐Mas, Mahmoud M.; Abdel‐Rahman, Abdel A.

doi:10.1016/j.lfs.2004.10.002

Cited by 28 publications

(17 citation statements)

References 42 publications

(79 reference statements)

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“…At 11 and 27 weeks of age, unrestrained unanesthetized male SHRs have a 24-h mean arterial pressure (MAP) of 135 and 150 mmHg, respectively, in contrast to 100 and 105 mmHg for the normal WKY at these two ages [71][72][73]. At 18-24 months of age, 57% of male SHRs have been shown to progress from hypertension-induced compensated hypertrophy to decompensated HF, with 13% surviving without HF and 30% dying or euthanized due to non-cardiac reasons (e.g., stroke, tumor, or debilitation) [74].…”

Section: Genetic Modelsmentioning

confidence: 99%

Merits of Non-Invasive Rat Models of Left Ventricular Heart Failure

et al. 2011

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Heart failure (HF) is characterized as a limitation to cardiac output that prevents the heart from supplying tissues with adequate oxygen and predisposes individuals to pulmonary edema. Impaired cardiac function is secondary to either decreased contractility reducing ejection (systolic failure), diminished ventricular compliance preventing filling (diastolic failure), or both. To study HF etiology, many different techniques have been developed to elicit this condition in experimental animals, with varying degrees of success. Among rats, surgically induced HF models are the most prevalent, but they bear several shortcomings, including high mortality rates and limited recapitulation of the pathophysiology, etiology, and progression of human HF. Alternatively, a number of non-invasive HF induction methods avoid many of these pitfalls, and their merits in technical simplicity, reliability, survivability, and comparability to the pathophysiologic and pathogenic characteristics of HF are reviewed herein. In particular, this review focuses on the primary pathogenic mechanisms common to genetic strains (spontaneously hypertensive and spontaneously hypertensive heart failure), pharmacological models of toxic cardiomyopathy (doxorubicin and isoproterenol), and dietary salt models, all of which have been shown to induce left ventricular HF in the rat. Additional non-invasive techniques that may potentially enable the development of new HF models are also discussed.

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Section: Genetic Modelsmentioning

confidence: 99%

Merits of Non-Invasive Rat Models of Left Ventricular Heart Failure

et al. 2011

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“…The SHRs have extensively been explored in chronobiological aspect [9][10][11] . Experimental data have shown abnormality of the hippocampal structure, neurochemistry and behavior in SHRs [12][13][14] .…”

Section: Expert Hypothesismentioning

confidence: 99%

“…The disturbances of physiological circadian rhythms underline a number of impaired processes characteristic for epileptic state as well. At twenty weeks of age, SHRs compared to WKY, are characterized by alterations in circadian autonomic profile, inverted diurnal patterns of heart rate, locomotor activity and respiration [9] . As concerns circadian fluctuations of blood pressure in SHRs, experimental data are controversial [9,10,21] though altered function of the suprachiasmatic nuclei (SCN) might explain disturbed diurnal activity rhythm of SHRs [10,22] .…”

Section: Expert Hypothesismentioning

confidence: 99%

“…At twenty weeks of age, SHRs compared to WKY, are characterized by alterations in circadian autonomic profile, inverted diurnal patterns of heart rate, locomotor activity and respiration [9] . As concerns circadian fluctuations of blood pressure in SHRs, experimental data are controversial [9,10,21] though altered function of the suprachiasmatic nuclei (SCN) might explain disturbed diurnal activity rhythm of SHRs [10,22] . Our previous finding showing higher locomotion of intact SHRs compared to normotensive Wistar rats at selected time points [18] are in line with the suggested dysfunction of the SCN.…”

Section: Expert Hypothesismentioning

confidence: 99%

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Finding a model for comorbidity between attention deficit hyperactivity disorder and epilepsy

2014

Mol Cell Epilepsy

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Close relationships between attention deficit hyperactivity disorder (ADHD) and epilepsy has been suggested due to prevalence of ADHD symptoms among patients with epilepsy than in the general population. Like epilepsy-depression connection, bi-directional relationships are suggested to underlie the predisposition of patients with ADHD to epilepsy and vice versa. Spontaneously hypertensive rats (SHRs) are characterized with typical behavioral symptoms such as hyperactivity, an attention deficit and impulsiveness, deficient sustained attention and decreased monoamine functioning. Our experimental findings suggest that SHRs might be used as a relevant model of comorbidity between ADHD and epilepsy. Spontaneously hypertensive rats demonstrate abnormal electrophysiological and behavioral characteristics as well as monoamine deficit in the frontal cortex and the hippocampus, which are also evident in epileptic rats. In addition, SHRs shows higher seizure susceptibility in models of temporal lobe epilepsy and disturbed circadian rhythms. Taken together, experimental findings suggest that SHRs could be used to explore the mechanism underlying bi-directional link of ADHD and epilepsy and as a screening method for mechanism-driven therapeutic approaches.

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“…Measurement of blood pressure and heart rate using telemetry system The telemetry system (Data Sciences International, St. Paul, MN) was used to measure mean arterial pressure (MAP), systolic blood pressure (SBP) and heart rate (HR) as described previously (El-Mas and Abdel-Rahman 2005). This blood pressure monitoring system consists of an implantable transmitter (radio frequency transducer model TA11PA C40), radio receiver panel, consolidation matrix, and personal computer-based data acquisition system.…”

Section: Animalsmentioning

confidence: 99%

Synergistic decrease in blood pressure by captopril combined with losartan in spontaneous hypertensive rats

Shin

Choi

et al. 2009

Arch. Pharm. Res.

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This study was designed to examine the anti-hypertensive effect of the combination therapy of captopril with losartan by oral administration using both independent and cross-over experimental protocols. In independent experimental protocols, four different groups of spontaneous hypertensive rats (SHR) were treated for 1 or 2 weeks: control, captopril (20 mg/kg/day), losartan (20 mg/kg/day), and combination captopril (10 mg/kg/day) with losartan (10 mg/kg/day). In cross-over protocols, each SHR received all four treatments for 1 or 3 days with an interval of several days between each injection for washing-out and return to high blood pressure (BP) levels. BP and heart rate (HR) were measured in conscious telemetered SHR. According to the results from the independent protocol, regardless of a 1- or 2-week administration period, combination therapy with low doses of captopril and losartan had a greater anti-hypertensive effect than individual high-dose monotherapy. Similarly, results from the cross-over protocol showed that regardless of 1-day or 3-day administration, the decrease in BP in the 11(th) and 12(th) hour after administration was greatest with the combination of low-dose captopril and losartan. Therefore, combination therapy with low doses of captopril with losartan lowered BP to a greater extent than a high dose of either individual monotherapy.

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Longitudinal studies on the effect of hypertension on circadian hemodynamic and autonomic rhythms in telemetered rats

Cited by 28 publications

References 42 publications

Merits of Non-Invasive Rat Models of Left Ventricular Heart Failure

Merits of Non-Invasive Rat Models of Left Ventricular Heart Failure

Finding a model for comorbidity between attention deficit hyperactivity disorder and epilepsy

Synergistic decrease in blood pressure by captopril combined with losartan in spontaneous hypertensive rats

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