Murine Cardiac Function

Kass, David A.; Hare, Joshua M.; Georgakopoulos, Dimitrios

doi:10.1161/01.res.82.4.519

Cited by 158 publications

(115 citation statements)

References 34 publications

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“…These values compare with in situ left ventricular pressures of -1 10 mmHg (Georgakopoulos et al 1998), and +dPldt values L 8000 mmHg s-' (Hoit et al 1997;Georgakopoulos et al 1998). Prior estimates of contractility are therefore as low as 10% of in situ values.…”

Section: Normoxic Function and Stabilitymentioning

confidence: 58%

Functional properties and responses to ischaemia‐reperfusion in Langendorff perfused mouse heart

Headrick¹,

Peart²,

Hack³

et al. 2001

Experimental Physiology

112

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Despite minimal model characterisation Langendorff perfused murine hearts are increasingly employed in cardiovascular research, and particularly in studies of myocardial ischaemia and reperfusion. Reported contractility remains poor and ischaemic recoveries variable. We characterised function in C57/BL6 mouse hearts using a ventricular balloon or apicobasal displacement and assessed responses to 10-30 min global ischaemia. We examined the functional effects of pacing, ventricular balloon design, perfusate filtration, [Ca"] and temperature. Contractility was high in isovolumically functioning mouse hearts (measured as the change in pressure with time (+dP/dt), 6000-7000 mmHg s-I) and was optimal at a heart rate of -420 beats min-', with the vasculature sub-maximally dilated, and the cellular energy state high. Post-ischaemic recovery (after 40 min reperfusion) was related to the ischaemic duration: developed pressure recovered by 82 f YO, 73 f 4u/, 68 f 3%, 57 f 2% and 41 f 5% after 10, 15, 20, 25 and 30 min ischaemia, respectively. Ventricular compliance and elastance were both reduced post-ischaemia. Post-ischaemic recoveries were lower in the apicobasal model (80 +-4 YO, 58 k 7 YO, 40 +-3 %, 32 +-7 % and 25 2 5 YO) despite greater reflow and lower metabolic rate (pre-ischaemic myocardial O2 consumption (Vo2,,,,) 127 f 15 vs. 198 k 17 p l O2 min-' g-'), contracture, enzyme and purine efflux. Electrical pacing slowed recovery in both models, small ventricular balloons (unpressurised volumes C 50-60 p1) artificially depressed ventricular function and recovery from ischaemia, and failure to filter the perfusion fluid to C 0.45 pm depressed pre-and post-ischaemic function. With attention to these various experimental factors, the buffer perfused isovolumically contracting mouse heart is shown to be stable and highly energised, and to possess a high level of contractility, The isovolumic model is more reliable in assessing ischaemic responses than the commonly employed apicobasal model. Experimental Physiology (200 1) 86.6, 703-7 16.

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Section: Normoxic Function and Stabilitymentioning

confidence: 58%

Functional properties and responses to ischaemia‐reperfusion in Langendorff perfused mouse heart

Headrick¹,

Peart²,

Hack³

et al. 2001

Experimental Physiology

112

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“…These results are consistent with the hypothesis that the intact CD-1 murine heart functions near maximal contractility in the basal state and thus does not have a large cardiac reserve. 5 Alvarez et al 12 and Cingolani and coworkers 13 demonstrated that mechanical stretch produces autocrine release of angiotensin II, which via stimulation of AT 1 receptors induces the formation and release of endothelin. Endothelin stimulates the Na ϩ -H ϩ exchanger, increasing intracellular Na ϩ , which in turn activates the Na ϩ -Ca 2ϩ exchanger, with subsequent elevation in intracellular Ca 2ϩ and augmented contractile performance.…”

Section: Discussionmentioning

confidence: 99%

“…3,4 These findings have led to the hypothesis that the intact murine heart functions at or near maximal contractility in the basal state, such that there is an inherently limited cardiac reserve. 5 If this hypothesis is correct, extrapolation of results on ventricular function of genetically altered mice to other species must be made with caution.…”

mentioning

confidence: 99%

Enhancement of Contractility With Sustained Afterload in the Intact Murine Heart

et al. 2003

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Background-It has been hypothesized that because of its rapid heart rate, the intact murine heart functions near maximal contractility in the basal state. If this hypothesis is correct, then the fast and slow components of myocardial length-dependent activation should be blunted compared with larger mammals. Methods and Results-Mice (nϭ24) were anesthetized, and via an open chest, LV pressure-volume relationships were determined by a dual-frequency conductance catheter system. Baseline pressure-volume relationships were determined during transient occlusion of the inferior vena cava, and repeat measurements were made after 1 (nϭ10) and 7 (nϭ21) minutes of sustained aortic occlusion. Control experiments were performed in a subset of mice (nϭ3

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“…Há uma série de diferenças entre o sistema cardiovascular de mamíferos de grande porte, incluindo humanos, e pequenos mamíferos, além disto, a resposta a xenobióticos também (Swynghedauwn et al, 1997b;Kass et al, 1998;Gehrmann et al, 2000;Routledge et al, 2002).…”

Section: Discussionunclassified

Efeitos cardiopulmonares da exposição ao material particulado fino (MP2,5) proveniente do concentrador de partículas ambientais (CPA) na hipertrofia ventricular esquerda de ratos wistar

Belotti¹

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Aos amigos Luiz Afonso Pires, Mac Gayver da Silva Castro e RobsonSeriani pela amizade e companheirismo durante o todo o período de estudo e divertimento.Ao Guilherme, Gabriel e Laís minha sincera gratidão pela ajuda e dedicação que foram oferecidas neste trabalho. Epidemiological and experimental studies have consistently shown that both short-and long-term exposures to air pollution are associated with a variety of cardiovascular diseases. Air pollution is composed by a mixture of noxious substance including particles and gases. The cardiovascular adverse effects are more commonly attributed to particles and toxicological experiments have demonstrated several mechanisms by which particle exposure may trigger these effects. In this study we investigated the effects of time (7, 15 and 21 days) of exposure to concentrated ambient particles (dose = 600 µg/m³) on morphofunctional parameters of the heart in normal and rats with left ventricular hypertrophy (LVH) induced by isoproterenol (nonselective β-adrenergic agonist with direct action) (1.2 mg/kg). The use of LVH rats was motivated by the fact that individuals with cardiovascular diseases are considered at higher risk for effect of ambient PM. Our data have shown that time is an important factor on the magnitude of the effects of concentrated ambient particles on heart function and morphology, as shown by increased HRV (heart rate variability), decreased heart rate and increased volume of connective tissue in left ventricle myocardium. LVH rats presented similar outcomes but more severe effects on the heart which included decreased blood pressure and increased cardiomyocyte hypertrophy compared to non-exposed LVH rats. In conclusion, our results corroborate with previous findings that particulate air pollution induces changes in the autonomic control of the heart and that individual with previous cardiovascular disease are more affected than normal ones. We have further shown that concentrated ambient particles are capable of inducing changes in the microstructure of the myocardium depending on accumulated dose of exposure. SUMÁRIO Lista de quadros

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Murine Cardiac Function

Cited by 158 publications

References 34 publications

Functional properties and responses to ischaemia‐reperfusion in Langendorff perfused mouse heart

Functional properties and responses to ischaemia‐reperfusion in Langendorff perfused mouse heart

Enhancement of Contractility With Sustained Afterload in the Intact Murine Heart

Efeitos cardiopulmonares da exposição ao material particulado fino (MP2,5) proveniente do concentrador de partículas ambientais (CPA) na hipertrofia ventricular esquerda de ratos wistar

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