Relationship between structure and function of liver mitochondria from hibernating and active ground squirrels, Citellus undulatus

Brustovetsky, N.N.; Mv, Egorova; Iljasova, E.N.; Bakeeva, L. E.

doi:10.1016/0305-0491(93)90017-y

Cited by 16 publications

(11 citation statements)

References 8 publications

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“…The values reported in this study, however, are similar to those from dwarf Siberian hamster liver mitochondria measured using the same techniques (Brown et al, 2007). Brustovetsky and colleagues (Brustovetsky et al, 1993) claim that, in S. undulatus, the liver mitochondrial volume decreases in hibernation (although the actual volume change was not quantified), whereas Martin and colleagues (Martin et al, 1999) reported no volume change with hibernation in S. lateralis. Volume changes are thought to have minimal impact when TPP + is used to estimate ΔΨ m (Rottenberg, 1984).…”

Section: Kinetics Of Proton Leaksupporting

confidence: 65%

Effects of dietary polyunsaturated fatty acids on mitochondrial metabolism in mammalian hibernation

Gerson

Brown

Thomas

et al. 2008

Journal of Experimental Biology

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SUMMARYThirteen-lined ground squirrels (Spermophilus tridecemlineatus) were fed one of four isocaloric, isolipemic diets containing 16, 22, 35 or 55 mg linoleic acid (18:2n-6) per gram. Mitochondrial properties were compared between hibernating and summer active states, and between diet groups. As in other studies, state 3 respiration was significantly reduced in hibernation, but only in animals fed the 22 mg g -1 18:2 diet. In the other diet groups, there was no difference in state 3 respiration between the hibernating and summer active groups. In the 22 mg g -1 18:2 diet group, there was no difference in mitochondrial proton conductance between hibernating and summer active animals, again in agreement with earlier studies. However, for all other diet groups, mitochondrial proton conductance was significantly reduced during hibernation. Mitochondrial phospholipid fatty acids changed significantly with hibernation, including increases in unsaturation indices and n-6/n-3, but no differences were found among diet groups. Mitochondrial proton conductance in hibernation showed a positive correlation with the content of linoleic acid (18:2) and arachidonic acid (20:4) in mitochondrial phospholipids. Lipid peroxidation was higher in mitochondria from hibernating animals, probably due to higher unsaturation, but there was no effect of dietary 18:2 on this pattern. Despite the dietary effects on mitochondrial metabolism, all animals hibernated with no differences in bout durations, body temperatures or whole-animal metabolic rates among the diet groups. The reduced mitochondrial proton leak in the 15, 35 and 55 mg g -1 18:2 diet groups might compensate for the inability to suppress respiration, permitting whole-animal energy savings over the hibernation season.

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Section: Kinetics Of Proton Leaksupporting

confidence: 65%

Effects of dietary polyunsaturated fatty acids on mitochondrial metabolism in mammalian hibernation

Gerson

Brown

Thomas

et al. 2008

Journal of Experimental Biology

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“…they have reduced coupling efficiency compared with their active counterparts. During dormancy rates of ATP synthesis are decreased; however, proton leak rates remain at pre-hibernation levels (Liu et al, 1969;Pehowich and Wang, 1984;Gehnrich and Aprille, 1988;Brustovetsky et al, 1989;Brustovetsky et al, 1990;Brustovetsky et al, 1993;Martin et al, 1999). While this seems counterintuitive to the animal's need to conserve energy stores, it is likely that due to the endothermic nature of mammalian hibernators, proton leak is maintained to preserve a basal level of metabolism and heat production.…”

Section: Discussionmentioning

confidence: 99%

“…Because mitochondrial function underlies not only cellular but also tissue and whole organism aerobic metabolic rate, a reduction in mitochondrial oxygen consumption would result in significant energy savings during metabolic depression. Indeed, in hibernating and aestivating animals, rates of mitochondrial oxygen consumption decrease during dormancy (Pehowich and Wang, 1984;Gehnrich and Aprille, 1988;Brustovetsky et al, 1990;Brustovetsky et al, 1993;Martin et al, 1999;Bishop and Brand, 2000;Bishop et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Surviving the drought: burrowing frogs save energy by increasing mitochondrial coupling

Kayes

Cramp

Hudson

et al. 2009

Journal of Experimental Biology

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SUMMARYDuring dormancy energy conservation is a key priority and as such dormant animals undergo a major metabolic depression to conserve their limited endogenous fuel supplies. Mitochondrial coupling efficiency, the efficiency with which mitochondria convert oxygen into ATP, significantly affects aerobic metabolism and thus to maximise energy savings during dormancy it has been hypothesised that coupling efficiency should increase. However, previous studies have shown coupling efficiency to be maintained or even to decrease. In this study we measured state 3 and state 4 mitochondrial respiration in the muscle of the burrowing frog, Cyclorana alboguttata and calculated the respiratory control ratio as a measure of coupling efficiency. After 7 months in aestivation, C. alboguttata significantly reduced oxygen consumption of isolated mitochondria by 83% and, unlike other dormant animals, the frogs appeared to decrease rates of proton leak to a greater extent than ATP synthesis, consistent with an increase in mitochondrial coupling efficiency. The significant energy savings observed at the mitochondrial level were reflected at higher levels of biological organisation, with tissue oxygen consumption depressed by as much as 81% and whole animal metabolic rate by 82%. Cyclorana alboguttata can survive in a dormant state for several years and we propose the hypothesis that energy efficiency is increased during aestivation.

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“…I therefore suggest that during hibernation, only some part of the mitochondria which have the orthodox configuration, make an essential contribution to the respiration. Important results were obtained by parallel recording of the oxygen consumption and analysis of the mitochondrial ultrastructure [35]. It was found that mitochondria from both active and hibernating animals were in the condensed configuration after their isolation and storing in the cold.…”

Section: Insight Into Nature Of Liver Mitochondrial Energetics Duringmentioning

confidence: 99%

Living unicellular eukaryote Tetrahymena pyriformis as a model for study

Mokhova¹

2011

Nature Precedings

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Some animals are able to survive for long time under conditions of drastically reduced oxidative metabolism, called metabolic depression. The most investigated type of the metabolic depression is hibernation. Research into the basic properties of liver mitochondria energetics during hibernation is essential for fundamental biology and medicine. However, the absence of the suitable hepatocyte culture makes it impossible to study the characteristic features of mitochondrial metabolic states in living cells during hibernation. We proposed that under selected conditions, the unicellular eukaryote Tetrahymena pyriformis resembles hepatocytes under hibernation, as (i) both cell types survive under condition of restricted food supply, hypoxia, and accumulation of toxic products of metabolism; (ii) the mechanisms for survival during drastically reduced oxidative metabolism probably developed in the ancestors of the eukaryote mitochondria and may be conserved, in somewhat modified forms, in mitochondria of the ciliates and mammalian cells; (iii) mitochondria isolated from rat liver and Tetrahymena pyriformis are similar in their energetics properties The already published results of experiments with Tetrahymena pyriformis and with mitochondria isolated from the liver of hibernating animals are considered. In this paper to support and develop this suggestion. Sharp decrease in the maximal uncoupler-stimulated respiration rates in liver mitochondria isolated from the hibernating animals was described in many publications. The respiration recordings and Mito Tracker Red fluorescence observations in the ciliates were tentatively explained by low ∆Ψ and high ∆pH. Prior to this study the strong decline in ∆Ψ and the subsequent remodeling of mitochondria into the condensed configuration was found during earlier apoptosis induced by suppression of the respiratory activity. On the grounds of these and other data, a hypothesis is put forward that the prerequisite for reducing the oxidative metabolism and mitochondrial transition to hibernation resembles the early apoptosis, with initial ∆Ψ decline with following mitochondrial matrix transition to a condense configuration. Correct comparison of ∆Ψ of mitochondria isolated from liver of the active and hibernating animals is difficult as probably they have different matrix volumes and energy-independent binding with the ∆Ψ probes.

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Relationship between structure and function of liver mitochondria from hibernating and active ground squirrels, Citellus undulatus

Cited by 16 publications

References 8 publications

Effects of dietary polyunsaturated fatty acids on mitochondrial metabolism in mammalian hibernation

Effects of dietary polyunsaturated fatty acids on mitochondrial metabolism in mammalian hibernation

Surviving the drought: burrowing frogs save energy by increasing mitochondrial coupling

Living unicellular eukaryote Tetrahymena pyriformis as a model for study

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