Life on Low Flame in Hibernation

  title={Life on Low Flame in Hibernation},
  author={Gerhard Heldmaier},
  pages={866 - 867}
In hibernating black bears, changes in metabolic rate and core body temperature occur independently. Do bears really hibernate? Their high body temperature during winter dormancy has raised some doubt about this behavior, as it is unlike the pronounced decreases observed in small mammals that enter this nonactive state. On page 906 of this issue, Tøien et al. (1) show that bears do indeed hibernate. Through continuous measurement of oxygen consumption, body temperature, and heart, muscle, and… 

Life in the fat lane: seasonal regulation of insulin sensitivity, food intake, and adipose biology in brown bears

Hibernating bears remained euglycemic, possibly due to hyperinsulinemia and hyperglucagonemia, and adipokine concentrations were relatively low throughout the active season but peaked in mid-October prior to hibernation when fat content was greatest.

Seasonal changes in eicosanoid metabolism in the brown bear

It is suggested that hibernation in bears is associated with a depressed state of the eicosanoid cascade, and plasma and muscle concentrations of the products of all pathways decreased significantly, or remained unchanged, independent of their pro- or anti-inflammatory properties.

Induction of Hypometabolism as a Novel Strategy to Minimize Ischemia Reperfusion Injury in Renal Reconstruction Surgeries

It is concluded that reprogramming of the kidney metabolism to a hypometabolic state before ischemia may protect the organ from oxidative damage and reduce ischemic/reperfusion injury.

Is metabolic rate a universal ‘pacemaker’ for biological processes?

  • D. S. Glazier
  • Biology
    Biological reviews of the Cambridge Philosophical Society
  • 2015
It is argued that a comprehensive understanding of the pace of life must include how biological activities depend on both energy and information and their environmentally sensitive interaction, supported by extensive evidence showing that hormones and other regulatory factors and signalling systems coordinate the processes of growth, metabolism and food intake in adaptive ways that are responsive to an organism's internal and external conditions.

On the Dissimilarity of 5′-AMP Induced Hypothermia and Torpor in Mice

Fundamental differences between 5′-AMP induced hypothermia and natural torpor are suggested, limiting the validity of the paradigm to the study of effects of hypothermic conditions and temperature related metabolic effects.

Neuronal plasticity in hibernation and the proposed role of the microtubule-associated protein tau as a "master switch" regulating synaptic gain in neuronal networks.

  • T. ArendtT. Bullmann
  • Biology
    American journal of physiology. Regulatory, integrative and comparative physiology
  • 2013
The concept that phosphorylation of tau is a neuroprotective mechanism to escape NMDA-mediated hyperexcitability of neurons that would otherwise occur during slow gradual cooling of the brain is put forward.

Hypometabolism as the ultimate defence in stress response: how the comparative approach helps understanding of medically relevant questions

  • T. Gorr
  • Biology
    Acta physiologica
  • 2017
An up‐to‐date survey of concepts and applications of a coordinated and reversibly down‐regulated metabolic rate as the ultimate defence in stress responses is presented.

Metabolic Scaling in Complex Living Systems

This heuristic attempt at building a unifying theory of metabolic scaling will not only stimulate further testing of all of the various subtheories composing it, but also foster an appreciation that many current models are, at least in part, complementary or even synergistic, rather than antagonistic.

Wärmehaushalt: Adaptation und Regulation

Es ist daher nicht verwunderlich, dass die Reaktionsgeschwindigkeiten (bio-)chemischer Reaktionen temperaturabhangig sind.



Hibernation in Black Bears: Independence of Metabolic Suppression from Body Temperature

The pronounced reduction and delayed recovery of metabolic rate in hibernating bears suggest that the majority of metabolic suppression during hibernation is independent of lowered body temperature.

Energetics of tropical hibernation

Tropical hibernation in C. medius is an effective, well-regulated adaptive response to survive unfavourable seasons, and the choice of the hibernaculum does not seem to be of energetic importance.

Advances in molecular biology of hibernation in mammals

  • M. Andrews
  • Biology
    BioEssays : news and reviews in molecular, cellular and developmental biology
  • 2007
The molecular events involved with remodeling metabolism, inducing hypothermia and maintaining organ function are discussed and considered with respect to analogous processes in non‐hibernating mammals such as mice and humans.

Mammalian hibernation: cellular and molecular responses to depressed metabolism and low temperature.

Detailed understanding of hibernation from the molecular to organismal levels should enable the translation of this information to the development of a variety of hypothermic and hypometabolic strategies to improve outcomes for human and animal health.

Mitochondrial metabolism in hibernation and daily torpor: a review

Respiratory suppression depends on in vitro assay temperature (no suppression is evident below ~30°C) and (at least in hibernation) dietary polyunsaturated fats, suggesting effects on inner mitochondrial membrane phospholipids.

Hibernation versus Daily Torpor in Mammals and Birds: Physiological Variables and Classification of Torpor Patterns

Comparisons of several physiological variables appear to justify a distinction between the two torpor patterns, but of all variables tested, only the frequency distributions of maximum torpor bout duration and the minimum V̇o2 showed a clear gap between daily heterotherms and hibernators.

Reversible depression of transcription during hibernation

It appears that hibernators are not specifically adapted to continue transcription during torpor, because of a moderate depression of initiation and a more severe inhibition of elongation due to temperature effects.

Mammalian hibernation: differential gene expression and novel application of epigenetic controls.

This review highlights current information about the regulatory mechanisms that govern gene expression during mammalian hibernation and proposes that epigenetic mechanisms such as DNA methylation, histone modification, SUMOylation and the actions of sirtuins play crucial roles in transcriptional suppression during torpor.

The Physiological Link between Metabolic Rate Depression and Tau Phosphorylation in Mammalian Hibernation

It is shown that in black bears hibernation is associated with conformational changes of highly phosphorylated tau protein that are typically related to neuropathological alterations, which might indicate a transitional state of a physiological process.