Myocardial ultrastructure of rats differing in resistance to hypoxia, after acute and periodic exposure to it

Luk’yanova, L. D.; Kleimenova, N. N.; Arefolov, V. N.; Dudchenko, A. M.

doi:10.1007/bf00839550

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“…Long-term (LT) adaptation of animals to hypoxia has been shown to cause mitochondrial hyperplasia [4,15], activate protein synthesis [7,11], and raise mitochondrial cytochrome c [19] and cytochrome c oxidase levels [15] and the concentration of functional respiratory units [18] in the myocardium. Such changes may boost the power of the cardiac energysynthesizing system, reduce the ATP and creatine phosphate deficits in the cardiac tissue [7,13], and mitigate the damaging effects of hypoxia on the functional and metabolic homeostasis of cardiac cells.…”

Section: Abstract: Adaptation; Hypoxia; Cytochromes; Brain; Liver; Imentioning

confidence: 99%

Effects of adaptation to hypoxia on cytochrome levels in the brain and liver of rats

Dudchenko

Luk’yanova

1995

Bull Exp Biol Med

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After a prolonged (for 30 days) adaptation of rats to intermittent hypoxia, their brains contained lowered levels of mitochondrial cytochromes, despite an increase in the number of mitochondria in the brain tissue mass, along with similar levels of high-energy compounds and more protein as compaired to the brains of unadapted controls. A mitochondrial population with novel properties presumably emerged in the brain. These effects were all more strongly marked in rats with an initially low resistance to hypoxia. In the liver of hypoxiaadapted animals, unlike in their brain, cytochrome levels in the mitochondrial and microsomal redox chains were lowered and the biogenesis of mitochondria was much less intensive. Key Words: adaptation; hypoxia; cytochromes; brain; liver; individual resistanceLong-term (LT) adaptation of animals to hypoxia has been shown to cause mitochondrial hyperplasia [4,15], activate protein synthesis [7,11], and raise mitochondrial cytochrome c [19] and cytochrome c oxidase levels [15] and the concentration of functional respiratory units [18] in the myocardium. Such changes may boost the power of the cardiac energysynthesizing system, reduce the ATP and creatine phosphate deficits in the cardiac tissue [7,13], and mitigate the damaging effects of hypoxia on the functional and metabolic homeostasis of cardiac cells. As regards brain and liver cells, the existing information on changes which their mitochondrial enzyme systems undergo during LT adaptation to hypoxia is highly inconclusive [1,15], probably because the respiratory chain in animals with an initially low resistance to hypoxia works differently than in highly resistant animals [5], making it hard to unravel the mechanisms by which adaptive changes occur in the energy-synthesizing system of the brain and liver. In view of this, the purpose of the present study was to examine and compare the effects of LT adaptation to intermittent hypoxia on respiratory chain cytoIxaboratory of Bioenergetics, Institute of Pharmacology, Russian Academy of Medical Sciences, Moscow chromes and on cytochromes of other redox chains in rats with high and low resistance to acute hypoxia. MATERIALS AND METHODSThe study was conducted on random-bred male rats (body weight 180-200 g) pretested for responsiveness to acute hypobaric hypoxia in a pressure chamber (at an "altitude" of 11,000 m) [5] and considered, on the basis of test results, to be highly resistant (HR) or lowresistant (LR) to acute hypoxia. Thereafter, a proportion of rats from both groups were adapted, in daily 5-h sessions for a total of 30 days, to an "altitude" of 5000 m in the pressure chamber; after 25 days of the adaptation period, they were retested for their ability to survive at 11,000 m. The remaining HR and LR rats served as unadapted controls. One day after the last session, all rats were sacrificed to remove the brain and liver and obtain material for assays. These were run separately in homogenates and in isolated mitochondrial and microsomal fractions because, as shown earlier [16],...

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Section: Abstract: Adaptation; Hypoxia; Cytochromes; Brain; Liver; Imentioning

confidence: 99%

Effects of adaptation to hypoxia on cytochrome levels in the brain and liver of rats

Dudchenko

Luk’yanova

1995

Bull Exp Biol Med

Self Cite

View full text Add to dashboard Cite

show abstract

Myocardial ultrastructure of rats differing in resistance to hypoxia, after acute and periodic exposure to it

Cited by 1 publication

References 0 publications

Effects of adaptation to hypoxia on cytochrome levels in the brain and liver of rats

Effects of adaptation to hypoxia on cytochrome levels in the brain and liver of rats

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