BACKGROUND Despite 5-7 months of physical inactivity during hibernation, brown bears (Ursus arctos) are able to cope with physiological conditions that would be detrimental to humans. During hibernation, the tissue metabolic demands fall to 25% of the active state. Our objective was to assess cardiac function associated with metabolic depression in the hibernating vs. active states in free-rang...

Hibernation is a strategy used by some mammals to survive a cold winter. Small hibernating mammals, such as squirrels and hamsters, use species- and tissue-specific antioxidant defenses to cope with oxidative insults during hibernation. Little is known about antioxidant responses and their regulatory mechanisms in hibernating bats. We found that the total level of reactive oxygen species (ROS) ...

Hibernation is an energy-saving strategy adopted by a wide range of mammals to survive highly seasonal or unpredictable environments. Arctic ground squirrels living in Alaska provide an extreme example, with 6- to 9-mo-long hibernation seasons when body temperature alternates between levels near 0 degrees C during torpor and 37 degrees C during arousal episodes. Heat production during hibernati...

Currently, it is believed that toad oocyte maturation is dependent on the physiological conditions of winter hibernation. Previous antibody-blocking experiments have demonstrated that toad ubiquitin carboxyl-terminal hydrolase L1 (tUCHL1) is necessary for germinal vesicle breakdown during toad oocyte maturation. In this paper, we first supply evidence that tUCHL1 is highly evolutionarily conser...

We suggest new evolutionary scenarios for non-magnetic short orbital period CVs. The first model is the analogy of the 'hibernation scenario' or the 'modern hibernation scenario'. The second one is an extension of Mukai & Naylor (1995) ideas. All models imply a tight connection between permanent superhump systems and classical novae. We highlight the significance of the observed evolution of V1...

We consider accretion onto the white dwarfs in cataclysmic variables in relation to nova eruptions, dwarf nova outbursts, hibernation and non-radial oscillations.

Reduced skeletal loading typically leads to bone loss because bone formation and bone resorption become unbalanced. Hibernation is a natural model of musculoskeletal disuse because hibernating animals greatly reduce weight-bearing activity, and therefore, they would be expected to lose bone. Some evidence suggests that small mammals like ground squirrels, bats, and hamsters do lose bone during ...

Some mammals hibernate in response to harsh environments. Although hibernating mammals may metabolize proteins, the nitrogen metabolic pathways commonly activated during hibernation are not fully characterized. In contrast to the hypothesis of amino acid preservation, we found evidence of amino acid metabolism as three of five key enzymes, including phenylalanine hydroxylase (PAH), homogentisat...