Sleep-waking pattern and body temperature in hypoxia at selected ambient temperatures

Hale, B.; Megirian, D.; Pollard, Marcus J.

doi:10.1152/jappl.1984.57.5.1564

Cited by 13 publications

(9 citation statements)

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“…Our observation of acute cold exposure suppression of sleep, EEG SWA, and body temperature in all 4 genotypes confirms prior observations in cats (31), rats (32)(33)(34), and mice (35). Cold-induced suppressed REMS is followed by rebound increases when mice (35) or rats (36,37) are returned to room temperature; we observed similar rebound increases in REMS.…”

Section: Discussionsupporting

confidence: 91%

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: Discussionsupporting

confidence: 91%

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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“…A pilot study (unpublished observations) showed that an ambient temperature of 29°C yielded the maximal amount of REM sleep in lean and obese Zucker rats, confirming earlier findings (19,24,28). Hale et al (9) showed that when rats breathe 10% O 2 at low ambient temperatures sleep organization is disrupted and body temperature (T b ) decreases. Furthermore, Pollard et al (19) next showed that rats, breathing even 15% O 2 , have their sleep organization altered without T b being affected.…”

supporting

confidence: 65%

Mechanism controlling sleep organization of the obese Zucker rats

Megirian

Dmochowski

Farkas

1998

Journal of Applied Physiology

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We tested the hypothesis that the obese (fa/fa) Zucker rat has a sleep organization that differs from that of lean Zucker rats. We used the polygraphic technique to identify and to quantify the distribution of the three main states of the rat: wakefulness (W), non-rapid-eye-movement (NREM), and rapid-eye movement (REM) sleep states. Assessment of states was made with light present (1000-1600), at the rats thermoneutral temperature of 29 degrees C. Obese rats, compared with lean ones, did not show significant differences in the total time spent in the three main states. Whereas the mean durations of W and REM states did not differ statistically, that of NREM did (P = 0.046). However, in the obese rats, the frequencies of switching from NREM sleep to W, which increased, and from NREM to REM sleep, which decreased, were statistically significantly different (P = 0.019). Frequency of switching from either REM or W state was not significantly different. We conclude that sleep organization differs between lean and obese Zucker rats and that it is due to a disparity in switching from NREM sleep to either W or REM sleep and the mean duration of NREM sleep.

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“…In keeping with the findings of Szymusiak and Satinoff (1981) and Hale et al (1984) in laboratory animals and with those of Haskell et al (1981) and Muzet et al (1983) obtained in humans the duration of REM sleep of our experimental piglets was markedly affected by thermal conditions. Under comfortable thermal conditions in our study REM sleep accounted for 20 % and 28 % of total sleeping time in 1-to 3-d old piglets and the two older age groups, respectively.…”

Section: Discussionsupporting

confidence: 91%

Thermal Environment, Sleep and Energy Metabolism in Piglets

Kotrbáček¹,

Hönig²

1989

Acta Vet. Brno

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Kotrbacek V., Z. Honig: Thermal Environment, Sleep and Energy Metabolism in Piglets. Acta vet. Bmo, 58, 1989: 185-195. Effects of different thermal conditions on rapid-eye-movement (REM) sleep and its influence on the level of energy metabolism in piglets are described.Heat production, respiratory quotient (RQ) and body temperature were measured in 1-to 9-d old piglets during the individual REM sleep episodes and compared with the respective values obtained in non-rapid-eye-movement (NREM) sleep. Two-hour measurements were carried out in· metabolic respiratory chambers under comfortable thermal conditions and upon exposure to cold.Thermal comfort was provided by heating the flocr to 37°C to 38 °C for 1-to 5-d old piglets and to 34°C to 36 °c for the older animals.The air temperature in the chamber ranged between 25°C and 26 0c.Exposure· to cold was produced by decreasing the floor temperature to 28 cc.Under cold exposure the total duration of REM sleep was reduced by 50 to 60 %. Both. the number of REM sleep episodes. and their duration were decreased. Heat production in REM sleep was invariably reduced. Under exposure to cold this decrease was highly significant (P < 0.01) owing to the disappearance of muscular tremor. However, concurrent decrease in body temperature, recorded in 1-to 3-d old piglets, was not significant.In the thermoneutral environment a significant (P < 0.05) decrease in heat production was observed during REM episodes occurring shortly after food intake. By depressing the postprandial thermogenesis, REM sleep contributes apparently to more effective utilization of the food energy.Lower RQ values observed in REM sleep are related to lower glucose oxidation under muscular atony. Sleep, thermal environment, oxygen consumption, RQ

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Sleep-waking pattern and body temperature in hypoxia at selected ambient temperatures

Cited by 13 publications

References 0 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

Mechanism controlling sleep organization of the obese Zucker rats

Thermal Environment, Sleep and Energy Metabolism in Piglets

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