Hibernation as a Model for Studies on Thermogenesis and its Control

Малан, А.

doi:10.1007/978-3-0348-5559-4_35

Cited by 15 publications

(3 citation statements)

References 28 publications

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“…Under natural short photoperiods, there is a reduction in food availability that is associated with many physiological changes (e.g. decreased body temperature and metabolic state, and weight loss; Malan, 1978; Pévet, 1987; Goldman, 2001). Moreover, torpor produces changes in SCN clock genes in Siberian hamsters (Herwig et al ., 2006) and its occurrence can be increased by food restriction (Paul et al ., 2004).…”

Section: Discussionmentioning

confidence: 99%

Circadian and photic regulation of clock and clock‐controlled proteins in the suprachiasmatic nuclei of calorie‐restricted mice

Mendoza

Pévet

Challet

2007

Eur J of Neuroscience

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In mammals, behavioural and physiological rhythms as well as clock gene expression in the central suprachiasmatic clock (SCN) are phase-shifted by a timed calorie restriction (T-CR; animals receiving at midday 66% of their daily food intake). The molecular mechanism of SCN depends on feedback loops involving clock genes and their protein products. To understand how T-CR mediates its synchronizing effects, we examined the rhythmic expression of three clock proteins, PERIOD (PER) 1, 2 and CLOCK, and one clock-controlled protein (i.e. vasopressin; AVP) in the SCN of mice either fed ad libitum (AL) or with T-CR. Moreover, we evaluated expression of these proteins in the SCN of AL and T-CR mice following a 1-h light pulse. The results indicate that, while PER1 and AVP rhythms were phase-advanced in T-CR mice, the PER2 rhythm showed an increased amplitude. CLOCK was expressed constitutively in AL mice while in T-CR it was significantly reduced, especially after feeding time. A light pulse produced a delayed increase in PER1 and a larger increase in PER2 expression in the SCN of T-CR mice than in AL animals. In addition, light exposure triggered an increase in AVP-ir cells in both AL and T-CR mice, and also of CLOCK expression but in T-CR mice only. The circadian changes in clock and clock-controlled proteins and their acute responses to light in the SCN of T-CR mice demonstrate that metabolic cues induced by a calorie restriction modulate the translational regulation of the SCN clock.

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Section: Discussionmentioning

confidence: 99%

Circadian and photic regulation of clock and clock‐controlled proteins in the suprachiasmatic nuclei of calorie‐restricted mice

Mendoza

Pévet

Challet

2007

Eur J of Neuroscience

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“…One might ask whether this change is a direct or an indirect result of hibernation. However, since the intracellular pH of the heart is not changed during hibernation (9), and prolonged cold exposure does not affect the electrical characteristics of mammalian myocardium (10), some possibilities for an indirect influence of hibernation can be eliminated. Although the precise explanation of this mechanism is not clear, it is interesting that in one animal myocardial properties can be exchanged in accordance with environmental changes.…”

mentioning

confidence: 99%

“…A number of the transforming genes molecularly cloned from human tumors and tumor cell lines have been shown to be cellular homologs of the oncogenes of the Harvey (rasH) and Kirsten (rasK) sarcoma viruses (4)(5)(6)(7)(8)(9). An additional ras-related cellular genetic locus, rasN, has been identified by transfer to NIH 3T3 cells with the use of DNA from the SK-N-SH neuroblastoma cell line (10).…”

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confidence: 99%

Calcium Source for Excitation-Contraction Coupling in Myocardium of Nonhibernating and Hibernating Chipmunks

Kondo

Shibata

1984

Science

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The amplitude of the early plateau phase of the action potential and the slow action potential of cardiac muscle were much lower in hibernating chipmunks than in nonhibernating chipmunks. The frequency-dependent contraction was decreased in hibernating animals but increased in nonhibernating animals. Caffeine caused a negative inotropic effect in hibernating animals but a positive inotropic effect in nonhibernating animals. Ryanodine caused greater inhibition in hibernating animals than in nonhibernating animals. These results suggest that the respective roles of the sources of calcium for cardiac excitation-contraction coupling are changed during hibernation.

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Energy expenditure and testosterone in free‐living male yellow‐pine chipmunks

et al. 2002

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The onset of mating in yellow-pine chipmunks (Tamias amoenus) follows emergence from a prolonged period of energy conservation during hibernation. Energy expenditures are greatly accelerated to meet the demands of the reproductive season. When emerging from hibernation, typical male chipmunks (breeders) have enlarged testes and a high level of plasma testosterone (T). However, certain males that do not participate in reproduction (nonbreeders) maintain small testes and low plasma T levels and emerge several weeks later than the breeders. The timing of the terminal arousal from hibernation and onset of mating are associated with increased plasma T levels. Experimental elevation of T levels in T. amoenus outside the mating season has been associated with a decrease in body mass, further suggesting an effect of T on energy balance. To test this hypothesis, we measured daily energy expenditure (DEE) in free-living, nonbreeding male chipmunks in the presence and absence of a T-implant. We also measured DEE in breeding males when endogenous T levels were high. DEE of the nonbreeders was not affected by our manipulation of plasma T, and the DEE of breeding males did not differ from that of nonbreeders. We conclude that energy expenditure on a daily basis in male yellow-pine chipmunks is not influenced by levels of T. However, on a seasonal basis, the earlier emergence from hibernation by breeding males, which appears to be influenced by T, represents an overall seasonal energy expenditure that exceeds that of nonbreeding males.

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Hibernation as a Model for Studies on Thermogenesis and its Control

Cited by 15 publications

References 28 publications

Circadian and photic regulation of clock and clock‐controlled proteins in the suprachiasmatic nuclei of calorie‐restricted mice

Circadian and photic regulation of clock and clock‐controlled proteins in the suprachiasmatic nuclei of calorie‐restricted mice

Calcium Source for Excitation-Contraction Coupling in Myocardium of Nonhibernating and Hibernating Chipmunks

Energy expenditure and testosterone in free‐living male yellow‐pine chipmunks

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