Circadian blood pressure variation in transgenic hypertensive rats.

Lemmer, Björn; Mattes, Andreas; Böhm, M; Ganten, Detlev

doi:10.1161/01.hyp.22.1.97

Cited by 180 publications

(92 citation statements)

References 11 publications

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“…Accordingly, a lower glomerular filtration rate and/or sodium reabsorption in mice compared with rats could contribute to lower Epo production and reduced Hct. In male rats raised at altitude, f H was around 500 beats min −1 , whereas normal sea level values of f H are around 250-300 beats min −1 during daytime and 350-400 beats min −1 during night-time (Lemmer et al, 1993). However, it is not possible from our data to elucidate whether the elevated f H effectively increases cardiac output or compensates for a reduced stroke volume.…”

Section: Discussionmentioning

confidence: 57%

Divergent physiological responses in laboratory rats and mice raised at high altitude

Jochmans-Lemoine

Villalpando

Gonzales

et al. 2015

Journal of Experimental Biology

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Ecological studies show that mice can be found at high altitude (HAup to 4000 m) while rats are absent at these altitudes, and there are no data to explain this discrepancy. We used adult laboratory rats and mice that have been raised for more than 30 generations in La Paz, Bolivia (3600 m), and compared their hematocrit levels, right ventricular hypertrophy (index of pulmonary hypertension) and alveolar surface area in the lungs. We also used whole-body plethysmography, indirect calorimetry and pulse oxymetry to measure ventilation, metabolic rate (O 2 consumption and CO 2 production), heart rate and pulse oxymetry oxygen saturation (p O2,sat ) under ambient conditions, and in response to exposure to sea level P O2 (32% O 2 =160 mmHg for 10 min) and hypoxia (18% and 15% O 2 =90 and 75 mmHg for 10 min each). The variables used for comparisons between species were corrected for body mass using standard allometric equations, and are termed mass-corrected variables. Under baseline, compared with rats, adult mice had similar levels of p O2,sat , but lower hematocrit and hemoglobin levels, reduced right ventricular hypertrophy and higher mass-corrected alveolar surface area, tidal volume and metabolic rate. In response to sea level P O2 and hypoxia, mice and rats had similar changes of ventilation, but metabolic rate decreased much more in hypoxia in mice, while p O2,sat remained higher in mice. We conclude that laboratory mice and rats that have been raised at HA for >30 generations have different physiological responses to altitude. These differences might explain the different altitude distribution observed in wild rats and mice.

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Section: Discussionmentioning

confidence: 57%

Divergent physiological responses in laboratory rats and mice raised at high altitude

Jochmans-Lemoine

Villalpando

Gonzales

et al. 2015

Journal of Experimental Biology

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“…Cosinor or spectral methods 11,12 are designed to identify the major frequency components of oscillatory behavior, and are therefore extremely powerful for studies in which this is the main feature of interest. Lemmer et al 11 used the former method to demonstrate differences between the circadian rhythms of Wistar-Kyoto (WKY), Sprague-Dawley, spontaneously hypertensive (SHR) and TGR[mRen-2]27 transgenic rats.…”

Section: Discussionmentioning

confidence: 99%

Telemetry for Cardiovascular Monitoring in a Pharmacological Study

et al. 1999

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Abstract-Radio-telemetry systems offer the ability to measure blood pressure and heart rate in experimental models of hypertension without the stress artifacts induced by some other methods. We therefore aimed to develop improved, nonparametric regression methods for radio-telemetry data and to use these to assess the effects of pharmacological interventions on cardiac and vascular hypertrophy in the stroke-prone spontaneously hypertensive rat. One control group and 5 groups treated either with losartan (alone or in combination with N G -nitro-L-arginine methyl ester [ L-NAME]), perindopril (also alone or in combination with L-NAME), or hydralazine plus hydrochlorothiazide were monitored for 4 weeks. Cardiac hypertrophy was assessed by the left ventricle plus septum weight to body weight ratio and vascular hypertrophy by flow-cytometry analysis of vascular smooth muscle cell polyploidy. Hemodynamic series were split into trend and cyclic components by the seasonal and trend decomposition procedure based on Loess and compared between groups by Loess regression modeling. Systolic and diastolic blood pressures were reduced systematically by losartan and perindopril (PϽ10 Ϫ10) but to a lesser extent by hydralazine plus hydrochlorothiazide (PϽ10 Ϫ8 ), and diurnal variation was reduced in the latter group (PϽ10 Ϫ6). L-NAME significantly reduced the hypotensive effect only of losartan. Vascular and cardiac hypertrophy were significantly attenuated with losartan or perindopril, but were unchanged with other treatments. The new analysis proposed here identifies differential effects on trends and cyclic variation and associations with regression of end-organ damage for losartan and perindopril compared with hydralazine plus hydrochlorothiazide. The method offers a powerful tool for detailed investigation of radio-telemetry data. Key Words: telemetry Ⅲ statistics Ⅲ hypertension, genetic Ⅲ hypertrophy, cardiac Ⅲ rats M onitoring of blood pressure and heart rate in experimental models of hypertension has played an important part in the study of cardiovascular physiology, pharmacology, and more recently in the genetics of hypertension. 1Ϫ3 A wide variety of techniques have been used to obtain these measurements. Anesthesia is the simplest method but it affects normal physiological regulation and thus measurements from conscious animals are preferred. 4 The most common techniques for monitoring conscious animals use tethers or restraining devices with measurements taken via indwelling exteriorized vascular catheters or blood pressure cuffs. 5 This use of restraints and tethers introduces a significant stress artifact with well-documented elevations of plasma catecholamines and cortisol. 6 In addition, the so called noninvasive tail-cuff measurements require both warming and restraint, thus producing several stressful stimuli.Radio-telemetry provides an alternative means of obtaining blood pressure and heart rate measurements from freely moving conscious animals. It provides the ability to collect data around the clock without ...

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“…In addition to the investigation of the diurnal rhythm, 49,54,55 radiotelemetry has been used to determine the effects of locomotor activity on blood pressure. A recent study in endothelial nitric oxide synthase (eNOS) knockout mice demonstrated that the size of the activity effect (23 mm Hg in controls, 33 mm Hg in eNOS knockouts) was far greater than the day-night difference in BP, or even the effect of knocking out the eNOS gene itself.…”

Section: Advantages and Applicationsmentioning

confidence: 99%

Recommendations for Blood Pressure Measurement in Humans and Experimental Animals

Kurtz¹,

Griffin²,

Bidani³

et al. 2005

Hypertension

256

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Abstract-In experimental animals, as in humans, techniques for measuring blood pressure (BP) have improved considerably over the past decade. In this document, we present recommendations for measuring BP in experimental animals with the goal of helping investigators select optimal methods for BP monitoring in the research laboratory. The advantages and disadvantages of various BP measurement methods are discussed and specific recommendations are provided for selecting the optimal technique depending on the study objective. Although indirect techniques that permit only sporadic measurements of BP may be suitable for some purposes, methods for directly measuring BP are generally preferred because of their ability to monitor the highly dynamic nature of BP in a comprehensive fashion. Selection of the methods to be used should ultimately be guided by the study objectives to insure that the techniques chosen are appropriate for the experimental questions being explored.

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Circadian blood pressure variation in transgenic hypertensive rats.

Cited by 180 publications

References 11 publications

Divergent physiological responses in laboratory rats and mice raised at high altitude

Divergent physiological responses in laboratory rats and mice raised at high altitude

Telemetry for Cardiovascular Monitoring in a Pharmacological Study

Recommendations for Blood Pressure Measurement in Humans and Experimental Animals

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