Bioenergetic remodeling of heart during treatment of spontaneously hypertensive rats with enalapril

We used spontaneously hypertensive rats to study remodeling of cardiac bioenergetics associated with changes in blood pressure. Blood pressure was manipulated with aggressive antihypertensive treatment combining low dietary salt and the angiotensin-converting enzyme inhibitor enalapril. Successive c...

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Bibliographic Details
Published in:American journal of physiology. Heart and circulatory physiology 2002-08, Vol.52 (2), p.H540-H548
Main Authors: LEARY, S. C, MICHAUD, D, LYONS, C. N, HALE, T. M, BUSHFIELD, T. L, ADAMS, M. A, MOYES, C. D
Format: Article
Language:English
Subjects:
Antihypertensive agents
Biological and medical sciences
Blood pressure
Cardiology
Cardiovascular system
Drug therapy
Heart
Hypertension
Medical sciences
Pharmacology. Drug treatments
Rodents
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Summary:We used spontaneously hypertensive rats to study remodeling of cardiac bioenergetics associated with changes in blood pressure. Blood pressure was manipulated with aggressive antihypertensive treatment combining low dietary salt and the angiotensin-converting enzyme inhibitor enalapril. Successive cycles of 2 weeks on, 2 weeks off treatment led to rapid, reversible changes in left ventricular (LV) mass (30% change in less than 10 days). Despite changes in LV mass, specific activities of bioenergetic (cytochrome-c oxidase, citrate synthase, lactate dehydrogenase) and reactive oxygen species (ROS) (total cellular superoxide dismutase) enzymes were actively maintained within relatively narrow ranges regardless of treatment duration, organismal age, or transmural region. Although enalapril led to parallel declines in mitochondrial enzyme content and ventricular mass, total ventricular mtDNA content was unaffected. Altered enzymatic content occurred without significant changes in relevant mRNA and protein levels. Transcript levels of gene products involved in mtDNA maintenance (Tfam), mitochondrial protein degradation (LON protease), fusion (fuzzy onion homolog), and fission (dynamin-like protein, synaptojanin-2) were also unchanged. In contrast, enalapril-mediated ventricular and mitochondrial remodeling was accompanied by a twofold increase in specific activity of catalase, an indicator of oxidative stress, suggesting that rapid cardiac adaptation is accompanied by tight regulation of mitochondrial enzyme activities and increased ROS production.
ISSN:0363-6135
1522-1539