scholarly journals Locomotor activity, core body temperature, and circadian rhythms in mice selected for high or low heat loss.

2001 ◽  
Vol 79 (4) ◽  
pp. 861 ◽  
Author(s):  
M R Mousel ◽  
W W Stroup ◽  
M K Nielsen
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Core Body

scholarly journals Elevated body temperature during sleep in orexin knockout mice

2006 ◽  
Vol 291 (3) ◽  
pp. R533-R540 ◽  
Author(s):  
Takatoshi Mochizuki ◽  
Elizabeth B. Klerman ◽  
Takeshi Sakurai ◽  
Thomas E. Scammell
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Biological Rhythms ◽  
Physiological Factors ◽  
Sustained Activity ◽  
Recovery Sleep ◽  
Core Body ◽  
Elevated Body Temperature

Core body temperature (Tb) is influenced by many physiological factors, including behavioral state, locomotor activity, and biological rhythms. To determine the relative roles of these factors, we examined Tb in orexin knockout (KO) mice, which have a narcolepsy-like phenotype with severe sleep-wake fragmentation. Because orexin is released during wakefulness and is thought to promote heat production, we hypothesized that orexin KO mice would have lower Tb while awake. Surprisingly, Tb was the same in orexin KO mice and wild-type (WT) littermates during sustained wakefulness. Orexin KO mice had normal diurnal variations in Tb, but the ultradian rhythms of Tb, locomotor activity, and wakefulness were markedly reduced. During the first 15 min of spontaneous sleep, the Tb of WT mice decreased by 1.0°C, but Tb in orexin KO mice decreased only 0.4°C. Even during intense recovery sleep after 8 h of sleep deprivation, the Tb of orexin KO mice remained 0.7°C higher than in WT mice. This blunted fall in Tb during sleep may be due to inadequate activation of heat loss mechanisms or sustained activity in heat-generating systems. These observations reveal an unexpected role for orexin in thermoregulation. In addition, because heat loss is an essential aspect of sleep, the blunted fall in Tb of orexin KO mice may provide an explanation for the fragmented sleep of narcolepsy.

Temporal phasing of locomotor activity, heart rate rhythmicity, and core body temperature is disrupted in VIP receptor 2-deficient mice

2011 ◽  
Vol 300 (3) ◽  
pp. R519-R530 ◽  
Author(s):  
Jens Hannibal ◽  
Hansen M. Hsiung ◽  
Jan Fahrenkrug
Keyword(s):  
Heart Rate ◽  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Wheel Running ◽  
Core Body Temperature ◽  
Running Activity ◽  
Wheel Running Activity ◽  
Core Body ◽  
Deficient Mice

Neurons of the brain's biological clock located in the hypothalamic suprachiasmatic nucleus (SCN) generate circadian rhythms of physiology (core body temperature, hormone secretion, locomotor activity, sleep/wake, and heart rate) with distinct temporal phasing when entrained by the light/dark (LD) cycle. The neuropeptide vasoactive intestinal polypetide (VIP) and its receptor (VPAC2) are highly expressed in the SCN. Recent studies indicate that VIPergic signaling plays an essential role in the maintenance of ongoing circadian rhythmicity by synchronizing SCN cells and by maintaining rhythmicity within individual neurons. To further increase the understanding of the role of VPAC2 signaling in circadian regulation, we implanted telemetric devices and simultaneously measured core body temperature, spontaneous activity, and heart rate in a strain of VPAC2-deficient mice and compared these observations with observations made from mice examined by wheel-running activity. The study demonstrates that VPAC2 signaling is necessary for a functional circadian clock driving locomotor activity, core body temperature, and heart rate rhythmicity, since VPAC2-deficient mice lose the rhythms in all three parameters when placed under constant conditions (of either light or darkness). Furthermore, although 24-h rhythms for three parameters are retained in VPAC2-deficient mice during the LD cycle, the temperature rhythm displays markedly altered time course and profile, rising earlier and peaking ∼4–6 h prior to that of wild-type mice. The use of telemetric devices to measure circadian locomotor activity, temperature, and heart rate, together with the classical determination of circadian rhythms of wheel-running activity, raises questions about how representative wheel-running activity may be of other behavioral parameters, especially when animals have altered circadian phenotype.

Ambulatory Estimation of Circadian Rhythms Shows Core Body Temperature Phase Precedes Slow Wave Sleep Phase in the Normal Elderly

2020 ◽  
Vol 87 (9) ◽  
pp. S251
Author(s):  
Esther Blessing ◽  
Ankit Paresh ◽  
Arleener Turner ◽  
Andrew Varga ◽  
David Rapoport ◽  
...  
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Slow Wave ◽  
Slow Wave Sleep ◽  
Core Body Temperature ◽  
Temperature Phase ◽  
Sleep Phase ◽  
Core Body

Infrared thermal imaging as a method to study thermogenesis in the neonatal lamb

2014 ◽  
Vol 54 (9) ◽  
pp. 1497 ◽  
Author(s):  
S. A. McCoard ◽  
H. V. Henderson ◽  
F. W. Knol ◽  
S. K. Dowling ◽  
J. R. Webster
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Cold Exposure ◽  
Thermal Imaging ◽  
Core Body Temperature ◽  
Recovery Period ◽  
Exposure Period ◽  
Skin Surface ◽  
Infrared Thermal Imaging ◽  
Core Body

The combination of heat generation and reducing heat loss from the skin surface is important for maintaining core body temperature in a neonate. Thermogenesis studies traditionally focus on measurement of core body temperature but not the contribution of radiated heat loss at the skin surface. This study aimed to evaluate the utility of using thermal imaging to measure radiated heat loss in newborn lambs. Continuous thermal images of newborn lambs were captured for 30 min each during the baseline (11−18°C), cold-exposure (0°C) and recovery (11−18°C) periods by using an infrared camera. Core body temperature measured by rectal thermometer was also recorded at the end of each period. In all, 7 of the 10 lambs evaluated had reduced rectal temperatures (0.4−1°C) between the baseline and recovery periods, while three maintained body temperature despite cold exposure. During the baseline period, infrared heat loss was relatively stable, followed by a rapid decrease of 5°C within 5 min of cold exposure. Heat loss continued to decrease linearly in the cold-exposure period by a further 10°C, but increased rapidly to baseline levels during the recovery period. A temperature change of between 20°C and 35°C was observed during the study, which was likely to be due to changes in vasoconstriction in the skin to conserve heat. The present study has highlighted the sensitivity of infrared thermal imaging to estimate heat loss from the skin in the newborn lamb and shown that rapid changes in heat loss occur in response to cold exposure.

scholarly journals Masking Effects of Posture and Sleep Onset on Core Body Temperature Have Distinct Circadian Rhythms: Results from a 90-Min/Day Protocol

2002 ◽  
Vol 17 (5) ◽  
pp. 447-462 ◽  
Author(s):  
Douglas E. Moul ◽  
Hernando Ombao ◽  
Timothy H. Monk ◽  
Qingxia Chen ◽  
Daniel J. Buysse
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Core Body Temperature ◽  
Sleep Onset ◽  
Core Body

scholarly journals Long-Term Bed Rest Delays the Circadian Phase of Core Body Temperature

2021 ◽  
Vol 12 ◽  
Author(s):  
Stefan Mendt ◽  
Katharina Brauns ◽  
Anika Friedl-Werner ◽  
Daniel L. Belavy ◽  
Mathias Steinach ◽  
...  
Keyword(s):  
Physical Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Core Body Temperature ◽  
Bed Rest ◽  
Phase Delay ◽  
Activity Levels ◽  
Physical Activity Levels ◽  
Core Body

Spaceflight can be associated with sleep loss and circadian misalignment as a result of non-24 h light-dark cycles, operational shifts in work/rest cycles, high workload under pressure, and psychological factors. Head-down tilt bed rest (HDBR) is an established model to mimic some of the physiological and psychological adaptions observed in spaceflight. Data on the effects of HDBR on circadian rhythms are scarce. To address this gap, we analyzed the change in the circadian rhythm of core body temperature (CBT) in two 60-day HDBR studies sponsored by the European Space Agency [n = 13 men, age: 31.1 ± 8.2 years (M ± SD)]. CBT was recorded for 36 h using a non-invasive and validated dual-sensor heatflux technology during the 3rd and the 8th week of HDBR. Bed rest induced a significant phase delay from the 3rd to the 8th week of HDBR (16.23 vs. 16.68 h, p = 0.005, g = 0.85) irrespective of the study site (p = 0.416, g = −0.46), corresponding to an average phase delay of about 0.9 min per day of HDBR. In conclusion, long-term bed rest weakens the entrainment of the circadian system to the 24-h day. We attribute this effect to the immobilization and reduced physical activity levels associated with HDBR. Given the critical role of diurnal rhythms for various physiological functions and behavior, our findings highlight the importance of monitoring circadian rhythms in circumstances in which gravity or physical activity levels are altered.

scholarly journals Circadian desynchronization of core body temperature and sleep stages in the rat

2007 ◽  
Vol 104 (18) ◽  
pp. 7634-7639 ◽  
Author(s):  
Trinitat Cambras ◽  
John R. Weller ◽  
Montserrat Anglès-Pujoràs ◽  
Michael L. Lee ◽  
Andrea Christopher ◽  
...  
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Slow Wave Sleep ◽  
Paradoxical Sleep ◽  
Core Body Temperature ◽  
The Other ◽  
Sleep Stages ◽  
Physical And Mental Health ◽  
Free Running ◽  
Core Body

Proper functioning of the human circadian timing system is crucial to physical and mental health. Much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. We have developed an animal model of human internal desynchrony in which rats are exposed to artificially short (22-h) light–dark cycles. Under these conditions, locomotor activity, sleep–wake, and slow-wave sleep (SWS) exhibit two rhythms within individual animals, one entrained to the 22-h light–dark cycle and the other free-running with a period >24 h (τ>24 h). Whereas core body temperature showed two rhythms as well, further analysis indicates this variable oscillates more according to the τ>24 h rhythm than to the 22-h rhythm, and that this oscillation is due to an activity-independent circadian regulation. Paradoxical sleep (PS), on the other hand, shows only one free-running rhythm. Our results show that, similarly to humans, (i) circadian rhythms can be internally dissociated in a controlled and predictable manner in the rat and (ii) the circadian rhythms of sleep–wake and SWS can be desynchronized from the rhythms of PS and core body temperature within individual animals. This model now allows for a deeper understanding of the human timekeeping mechanism, for testing potential therapies for circadian dysrhythmias, and for studying the biology of PS and SWS states in a neurologically intact model.

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