Slow wave sleep, shallow torpor and hibernation: Homologous states of diminished metabolism and body temperature

Berger, Ralph J.

doi:10.1016/0301-0511(84)90045-0

Cited by 91 publications

(39 citation statements)

References 83 publications

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“…This phenomenon, often called torpor, is thought to be analogous to hibernation (27). It is an energy-conserving state characterized by the suppression of metabolic rate, heart rate, ventilation, and body temperature, and metabolism shifts from carbohydrate oxidation to lipid metabolism.…”

Section: Discussionmentioning

confidence: 99%

The preproghrelin gene is required for the normal integration of thermoregulation and sleep in mice

Szentirmai

Kapás

Sun

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Peptidergic mechanisms controlling feeding, metabolism, thermoregulation, and sleep overlap in the hypothalamus. Low ambient temperatures and food restriction induce hypothermic (torpor) bouts and characteristic metabolic and sleep changes in mice. We report that mice lacking the preproghrelin gene, but not those lacking the ghrelin receptor, have impaired abilities to manifest and integrate normal sleep and thermoregulatory responses to metabolic challenges. In response to fasting at 17°C (a subthermoneutral ambient temperature), preproghrelin knockout mice enter hypothermic bouts associated with reduced sleep, culminating in a marked drop in body temperature to near-ambient levels. Prior treatment with obestatin, another preproghrelin gene product, attenuates the hypothermic response of preproghrelin knockout mice. Results suggest that obestatin is a component in the coordinated regulation of metabolism and sleep during torpor.EEG ͉ ghrelin ͉ metabolism ͉ obestatin ͉ torpor N atural shortages of food and low environmental temperature are commonly encountered in the wild. Small rodents tolerate these conditions by exhibiting torpor, a regulated drop in body temperature associated with behavioral hyporesponsiveness. Hormones and neuropeptides, including ghrelin and obestatin, play an integral role in the regulation of metabolism and energy balance (1, 2). Ghrelin promotes positive energy balance by stimulating feeding and suppressing energy expenditure (3). The role of obestatin, a distinct product of the preproghrelin gene, in the regulation of feeding and metabolism is less clear. Several (2, 4-6) but not all (7, 8) studies suggest that obestatin suppresses appetite and enhances energy expenditure.Ghrelin and obestatin may also regulate sleep. Sleep deprivation induces increases in hypothalamic and plasma ghrelin levels (9). In rats, administration of ghrelin facilitates wakefulness (10, 11), whereas injection of obestatin facilitates sleep (12). Wakefulness and feeding may be parallel outputs of a hypothalamic circuitry that involves neuropeptide Y-, orexin-, and ghrelinergic neurons (10, 11, 13). Sleep-wake activity (14) and metabolism (15) of preproghrelin knockout (KO) mice (originally named ghrelin Ϫ/Ϫ mice) are, however, relatively normal if the animals are kept at thermoneutral ambient temperature (30°C Ϯ 1°C) with food provided ad libitum. Under nonstressed conditions, redundant regulatory systems likely compensate for the lack of the preproghrelin gene product(s). We hypothesized that in a negative metabolic state, such as torpor, preproghrelin gene products might be involved in the coordinated regulation of energy sources and vigilance.In the present experiments we studied sleep and thermoregulatory responses to 3 days of cold exposure (17°C) and to the combined challenge of cold environmental temperature and fasting in preproghrelin KO and ghrelin receptor KO mice. We report that the ability to mount normal body temperature and sleep response to a metabolic challenge is greatly impaired in preproghr...

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Section: Discussionmentioning

confidence: 99%

The preproghrelin gene is required for the normal integration of thermoregulation and sleep in mice

Szentirmai

Kapás

Sun

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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“…Some animal models of obesity, including the obese (ob/ob) mouse [52,53] and the Zucker fatty (fa/fa) rat [54], are hypothermic compared with lean controls. Hibernation and the lesser state of shallow torpor wherein the temperature falls at night are energy-saving adaptations used by a variety of mammals [55,56] and even some human populations such as the Australian Aboriginals [57]. A decrease in body temperature, in fact, occurs at night in relation to the sleep cycle in human populations [58,59].…”

Section: Metabolic Rate Measurements In the Obesementioning

confidence: 97%

Is obesity associated with lower body temperatures? Core temperature: a forgotten variable in energy balance

Landsberg¹,

Young²,

Leonard³

et al. 2009

Metabolism

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“…Hibernation and sleep share similar features, including reduced metabolic rate, decreased core T b , and energy conservation (2). To date, no definitive answer to why animals sleep has been found (40).…”

Section: Perspectives and Significancementioning

confidence: 99%

Preference of IRES-mediated initiation of translation during hibernation in golden-mantled ground squirrels, Spermophilus lateralis

Pan

Breukelen

2011

American Journal of Physiology-Regulatory, Integrative and Comp

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Slow wave sleep, shallow torpor and hibernation: Homologous states of diminished metabolism and body temperature

Cited by 91 publications

References 83 publications

The preproghrelin gene is required for the normal integration of thermoregulation and sleep in mice

The preproghrelin gene is required for the normal integration of thermoregulation and sleep in mice

Is obesity associated with lower body temperatures? Core temperature: a forgotten variable in energy balance

Preference of IRES-mediated initiation of translation during hibernation in golden-mantled ground squirrels, Spermophilus lateralis

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