Central regulation of temperature in hibernation and normothermia

Mills, Steven H.; South, Frank E.

doi:10.1016/0011-2240(72)90156-3

Cited by 24 publications

(4 citation statements)

References 20 publications

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“…While arctic ground squirrels' T b during torpor remained relatively constant with decreasing T a , abdominal T b in golden-mantled ground squirrels increased by ∼0.97C between T a 's of 247 and 287C (from 20.087 5 0.167C to 0.957 5 0.257C, P p 0.08). Throughout the hibernation cycle, T b is closely monitored and regulated by the hypothalamus; as the hypothalamus is heated or cooled, the MR of the animal is suppressed or increased, ensuring that hypothalamic temperature does not deviate significantly from its setpoint (Heller and Hammel 1972;Mills and South 1972;Florant and Heller 1977). However, thermogenic animals exhibit regional heterothermy during torpor (Barnes 1989), and therefore it is unclear whether the observed difference in abdominal T b reflects a difference in hypothalamic set-point or was due to differences in heat transfer from the brown adipose tissue in the thoracic region.…”

Section: Discussionmentioning

confidence: 99%

Thermogenic Capacity at Subzero Temperatures: How Low Can a Hibernator Go?

Richter¹,

Williams²,

Lee³

et al. 2015

Physiological and Biochemical Zoology

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Hibernation in mammals is a physiological and behavioral adaptation to survive intervals of low resource availability through profound decreases in metabolic rate (MR), core body temperature (Tb), and activity. Most small mammalian hibernators thermoconform, with Tb approximating ambient temperature (Ta); arctic species are an exception, since they must actively defend what can be large thermal gradients between Tb and Ta. Here we compare the thermogenic capacity of the arctic ground squirrel (Urocitellus parryii) to that of the golden-mantled ground squirrel (Callospermophilus lateralis), a temperate-zone montane hibernator. We allowed animals to reenter torpor at sequentially lower Ta's and found that arctic ground squirrels maintained steady state torpor at Ta's as low as -26°C, through a 36-fold increase in torpid MR (TMR), compared to their minimum TMR, exhibited at a Ta of 0°C. Golden-mantled ground squirrels are able to maintain steady state torpor at Ta's at least as low as -8°C, through a 13.5-fold increase in MR, compared to their minimum TMR at a Ta of 2°C. In a second experiment, torpid animals were exposed to continuously decreasing Ta's (0.25°C/30 min); individuals of both species increased their metabolism while remaining torpid at low Ta's (as low as -30°C for arctic ground squirrels and -10°C for golden-mantled ground squirrels). Although the capacity to hibernate at subfreezing Ta's is not unique to arctic ground squirrels, their large body size, greater torpid metabolic scope, and previously ascribed capacity to supercool allow them to occupy much colder hibernacula for prolonged seasons of hibernation.

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Section: Discussionmentioning

confidence: 99%

Thermogenic Capacity at Subzero Temperatures: How Low Can a Hibernator Go?

Richter¹,

Williams²,

Lee³

et al. 2015

Physiological and Biochemical Zoology

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“…It seems clear that thermoreceptivity of CNS persists during hibernation. Hibernating animals increased oxygen consumption and maintained body temperature without arousal in response to cold stimulation (Lyman and O'Brien, 1972;Mills and South, 1972;Hammel et al, 1973;Heller and Colliver, 1974;Weidler et al, 1974). Whether NST contributes to temperature control during the maintenance stage of hibernation is unknown.…”

Section: Cns Control Of Nst During Hibernationmentioning

confidence: 99%

Arousal from hibernation and BAT thermogenesis against cold: central mechanism and molecular basis

Hashimoto

Gao

Kikuchi-Utsumi

et al. 2002

Journal of Thermal Biology

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“…Because of the well-known energetic benefits of social thermoregulation (Madison 1984), it would be expected that animals in large groups lose less mass. Low T, should affect the small infants more than older animals because of their more adverse surface/volume relationship and hence proportionally higher heat loss to the environment (Mills and South 1972;Thfiti 1978). However, a large group size mainly due to the presence of many infants increased mass loss (Fig.…”

Section: Discussionmentioning

confidence: 99%

The evolution of marmot sociality: II. Costs and benefits of joint hibernation

Arnold

1990

Behav Ecol Sociobiol

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Central regulation of temperature in hibernation and normothermia

Cited by 24 publications

References 20 publications

Thermogenic Capacity at Subzero Temperatures: How Low Can a Hibernator Go?

Thermogenic Capacity at Subzero Temperatures: How Low Can a Hibernator Go?

Arousal from hibernation and BAT thermogenesis against cold: central mechanism and molecular basis

The evolution of marmot sociality: II. Costs and benefits of joint hibernation

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