scholarly journals Circulation and metabolic rates in a natural hibernator: an integrative physiological model

2010 ◽  
Vol 299 (6) ◽  
pp. R1478-R1488 ◽  
Author(s):  
Marshall Hampton ◽  
Bethany T. Nelson ◽  
Matthew T. Andrews
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Core Body Temperature ◽  
Circulatory System ◽  
Physiological Model ◽  
Ground Squirrels ◽  
Metabolic Rates ◽  
Spermophilus Tridecemlineatus ◽  
Brown Adipose ◽  
Core Body

Small hibernating mammals show regular oscillations in their heart rate and body temperature throughout the winter. Long periods of torpor are abruptly interrupted by arousals with heart rates that rapidly increase from 5 beats/min to over 400 beats/min and body temperatures that increase by ∼30°C only to drop back into the hypothermic torpid state within hours. Surgically implanted transmitters were used to obtain high-resolution electrocardiogram and body temperature data from hibernating thirteen-lined ground squirrels ( Spermophilus tridecemlineatus ). These data were used to construct a model of the circulatory system to gain greater understanding of these rapid and extreme changes in physiology. Our model provides estimates of metabolic rates during the torpor-arousal cycles in different model compartments that would be difficult to measure directly. In the compartment that models the more metabolically active tissues and organs (heart, brain, liver, and brown adipose tissue) the peak metabolic rate occurs at a core body temperature of 19°C approximately midway through an arousal. The peak metabolic rate of the active tissues is nine times the normothermic rate after the arousal is complete. For the overall metabolic rate in all tissues, the peak-to-resting ratio is five. This value is high for a rodent, which provides evidence for the hypothesis that the arousal from torpor is limited by the capabilities of the cardiovascular system.

scholarly journals A refined method to monitor arousal from hibernation in the European hamster

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Fredrik A. F. Markussen ◽  
Vebjørn J. Melum ◽  
Béatrice Bothorel ◽  
David G. Hazlerigg ◽  
Valérie Simonneaux ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Behavioural Adaptation ◽  
Ventilation Frequency ◽  
Reduced Body ◽  
Brown Adipose ◽  
Invasive Method ◽  
Warming Rate ◽  
Core Body ◽  
Environmental Temperatures

Abstract Background Hibernation is a physiological and behavioural adaptation that permits survival during periods of reduced food availability and extreme environmental temperatures. This is achieved through cycles of metabolic depression and reduced body temperature (torpor) and rewarming (arousal). Rewarming from torpor is achieved through the activation of brown adipose tissue (BAT) associated with a rapid increase in ventilation frequency. Here, we studied the rate of rewarming in the European hamster (Cricetus cricetus) by measuring both BAT temperature, core body temperature and ventilation frequency. Results Temperature was monitored in parallel in the BAT (IPTT tags) and peritoneal cavity (iButtons) during hibernation torpor-arousal cycling. We found that increases in brown fat temperature preceded core body temperature rises by approximately 48 min, with a maximum re-warming rate of 20.9℃*h-1. Re-warming was accompanied by a significant increase in ventilation frequency. The rate of rewarming was slowed by the presence of a spontaneous thoracic mass in one of our animals. Core body temperature re-warming was reduced by 6.2℃*h-1 and BAT rewarming by 12℃*h-1. Ventilation frequency was increased by 77% during re-warming in the affected animal compared to a healthy animal. Inspection of the position and size of the mass indicated it was obstructing the lungs and heart. Conclusions We have used a minimally invasive method to monitor BAT temperature during arousal from hibernation illustrating BAT re-warming significantly precedes core body temperature re-warming, informing future study design on arousal from hibernation. We also showed compromised re-warming from hibernation in an animal with a mass obstructing the lungs and heart, likely leading to inefficient ventilation and circulation.

Relationship between metabolic rate and core body temperature during sleep in human

2015 ◽  
Vol 16 ◽  
pp. S186-S187 ◽  
Author(s):  
I. Park ◽  
M. Kayaba ◽  
K. Iwayama ◽  
H. Ogata ◽  
Y. Sengoku ◽  
...  
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Core Body Temperature ◽  
Core Body

scholarly journals Impaired Thermogenesis and a Molecular Signature for Brown Adipose Tissue inId2Null Mice

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Peng Zhou ◽  
Maricela Robles-Murguia ◽  
Deepa Mathew ◽  
Giles E. Duffield
Keyword(s):  
Adipose Tissue ◽  
Body Temperature ◽  
Brown Adipose Tissue ◽  
Energy Homeostasis ◽  
Core Body Temperature ◽  
Specific Pattern ◽  
Molecular Signature ◽  
Brown Adipose ◽  
Core Body ◽  
The Impact

Inhibitor of DNA binding 2 (ID2) is a helix-loop-helix transcriptional repressor rhythmically expressed in many adult tissues. Our previous studies have demonstrated thatId2null mice have sex-specific elevated glucose uptake in brown adipose tissue (BAT). Here we further explored the role ofId2in the regulation of core body temperature over the circadian cycle and the impact ofId2deficiency on genes involved in insulin signaling and adipogenesis in BAT. We discovered a reduced core body temperature inId2−/− mice. Moreover, inId2−/− BAT, 30 genes includingIrs1,PPARs, andPGC-1s were identified as differentially expressed in a sex-specific pattern. These data provide valuable insights into the impact ofId2deficiency on energy homeostasis of mice in a sex-specific manner.

scholarly journals Regulatory effects of brown adipose tissue thermogenesis on maternal metabolic adaptation, placental efficiency, and fetal growth in mice

2018 ◽  
Vol 315 (6) ◽  
pp. E1224-E1231 ◽  
Author(s):  
Liping Qiao ◽  
Samuel Lee ◽  
Amanda Nguyen ◽  
William W. Hay ◽  
Jianhua Shao
Keyword(s):  
Adipose Tissue ◽  
Body Temperature ◽  
Brown Adipose Tissue ◽  
Fetal Growth ◽  
Core Body Temperature ◽  
Metabolic Adaptation ◽  
Glucose Transporter 1 ◽  
Brown Adipose ◽  
Placental Efficiency ◽  
Core Body

To determine the role of UCP1-mediated thermogenesis in controlling maternal metabolic adaptation to pregnancy, energy metabolism of C57BL/6 wild-type (WT) and Ucp1 gene knockout ( Ucp1−/−) mice was studied during pregnancy. With the progression of pregnancy, maternal energy expenditure rates (EERs), expression of UCP1, and core body temperature steadily declined in WT dams. Despite no significant alterations in core body temperature and weight gain during pregnancy, Ucp1−/− dams exhibited lower rates in EER decline. High-fat (HF) feeding not only robustly increased maternal UCP1 expression and core body temperature but also abolished gestation-suppressed EER in WT dams. However, HF-increased EERs were significantly attenuated in Ucp1−/− dams. Significantly increased fetal body weights and fetal/placental weight ratio were detected in fetuses from Ucp1−/− dams compared with fetuses from WT dams. Markedly increased expression levels of glucose transporter 1 and amino acid transporters were also observed in placentas from Ucp1−/− dams. Furthermore, blood glucose concentrations of fetuses from Ucp1−/− dams were significantly higher than those of fetuses from WT dams, indicating that maternal UCP1 has an inhibitory effect on placental efficiency and fetal growth. Taken all together, this study demonstrated that maternal brown adipose tissue plays an important role in controlling maternal metabolic adaptation and placental nutrient transport.

scholarly journals Thermoregulatory inversion: a novel thermoregulatory paradigm

2017 ◽  
Vol 312 (5) ◽  
pp. R779-R786 ◽  
Author(s):  
Domenico Tupone ◽  
Georgina Cano ◽  
Shaun F. Morrison
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Neural Circuit ◽  
Core Body Temperature ◽  
Normal Body Temperature ◽  
Dorsomedial Hypothalamus ◽  
Pharmacological Mechanism ◽  
Brown Adipose ◽  
Skin Cooling ◽  
Core Body

To maintain core body temperature in mammals, the normal central nervous system (CNS) thermoregulatory reflex networks produce an increase in brown adipose tissue (BAT) thermogenesis in response to skin cooling and an inhibition of the sympathetic outflow to BAT during skin rewarming. In contrast, these normal thermoregulatory reflexes appear to be inverted in hibernation/torpor; thermogenesis is inhibited during exposure to a cold environment, allowing dramatic reductions in core temperature and metabolism, and thermogenesis is activated during skin rewarming, contributing to a return of normal body temperature. Here, we describe two unrelated experimental paradigms in which rats, a nonhibernating/torpid species, exhibit a “thermoregulatory inversion,” which is characterized by an inhibition of BAT thermogenesis in response to skin cooling, and a switch in the gain of the skin cooling reflex transfer function from negative to positive values. Either transection of the neuraxis immediately rostral to the dorsomedial hypothalamus in anesthetized rats or activation of A1 adenosine receptors within the CNS of free-behaving rats produces a state of thermoregulatory inversion in which skin cooling inhibits BAT thermogenesis, leading to hypothermia, and skin warming activates BAT, supporting an increase in core temperature. These results reflect the existence of a novel neural circuit that mediates inverted thermoregulatory reflexes and suggests a pharmacological mechanism through which a deeply hypothermic state can be achieved in nonhibernating/torpid mammals, possibly including humans.

Testosterone reduces metabolic brown fat activity in male mice

2021 ◽  
Author(s):  
Marta Lantero Rodriguez ◽  
Maaike Schilperoort ◽  
Inger Johansson ◽  
Elin Svedlund Eriksson ◽  
Vilborg Palsdottir ◽  
...  
Keyword(s):  
Body Temperature ◽  
Core Body Temperature ◽  
Negative Regulator ◽  
Acid Uptake ◽  
Male Mice ◽  
Brown Adipocytes ◽  
Bat Activity ◽  
Brown Adipose ◽  
Core Body

Brown adipose tissue (BAT) burns substantial amounts of mainly lipids to produce heat. Some studies indicate that BAT activity and core body temperature are lower in males than females. Here we investigated the role of testosterone and its receptor (the androgen receptor; AR) in metabolic BAT activity in male mice. Castration, which renders mice testosterone deficient, slightly promoted the expression of thermogenic markers in BAT, decreased BAT lipid content, and increased basal lipolysis in isolated brown adipocytes. Further, castration increased the core body temperature. Triglyceride-derived fatty acid uptake, a proxy for metabolic BAT activity in vivo, was strongly increased in BAT from castrated mice (4.5-fold increase vs. sham-castrated mice) and testosterone replacement reversed the castration-induced increase in metabolic BAT activity. BAT-specific AR deficiency did not mimic the castration effects in vivo and AR agonist treatment did not diminish the activity of cultured brown adipocytes in vitro, suggesting that androgens do not modulate BAT activity via a direct, AR-mediated pathway. In conclusion, testosterone is a negative regulator of metabolic BAT activity in male mice. Our findings provide new insight into the metabolic actions of testosterone.

scholarly journals Food Intake and Core Body Temperature of Pups and Adults in a db Mouse Line Deficient in the Long Form of the Leptin Receptor without Misty Mutation

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Wijang Pralampita Pulong ◽  
Miharu Ushikai ◽  
Emi Arimura ◽  
Masaharu Abe ◽  
Hiroaki Kawaguchi ◽  
...  
Keyword(s):  
Food Intake ◽  
Body Temperature ◽  
Leptin Receptor ◽  
Uncoupling Protein ◽  
Core Body Temperature ◽  
Mrna Levels ◽  
Mouse Line ◽  
Brown Adipose ◽  
Long Form ◽  
Core Body

Different involvement of leptin signaling in food intake (FI) and body temperature (BT) in pups and adults has been suggested. However, the leptin receptor (Lepr) long-form-deficient (db) mouse line has not been fully examined in pups. In the most available db mouse line, wild-type (WT) mice have a mutation in the dedicator of cytokinesis 7 gene, named misty, which was recently revealed to be involved in neuronal development. Therefore, we established a line of db mice without the misty mutation using natural mating. Adult (8 weeks of age) homozygous db/db mice displayed significantly higher core body weight (BW) and FI and significantly lower core BT than WT mice. However, postnatal (2 weeks of age) db/db mice displayed similar BW and milk intake and significantly lower core BT than WT mice. Correspondingly, adult and postnatal db/db mice exhibited altered mRNA levels of hypothalamic orexigenic and anorexigenic peptide in adults but not in pups. Additionally, db/db mice displayed significantly lower mRNA levels of brown adipose tissue uncoupling protein 1 at both ages. In conclusion, the db mouse line without the misty mutation clearly showed the different involvements of the Lepr long form in FI and BT in pups and adults.

scholarly journals Contribution of nucleus raphe magnus to thermoregulation

2020 ◽  
Vol 24 (3) ◽  
pp. 165-173
Author(s):  
Masoumeh Kourosh Arami ◽  
◽  
Alireza Komaki ◽  
Shahriar Gharibzadeh ◽  
◽  
...  
Keyword(s):  
Body Temperature ◽  
Energy Homeostasis ◽  
Core Body Temperature ◽  
Nucleus Raphe Magnus ◽  
Brown Adipose ◽  
Raphe Magnus ◽  
Blood Flow Control ◽  
Core Body ◽  
Homeostatic Response ◽  
Cutaneous Vasoconstriction

Thermoregulation is the maintenance of the core body temperature. The regulation of body temperature is one of the most important functions of the nervous system. Nucleus raphe magnus, as a central circuit coordinates the homeostatic response and maintains body temperature during environmental temperature challenges and adjusts body temperature during the inflammatory response and behavioral states and in response to decreasing energy homeostasis. Our aim in this review is the understanding of thermoregulation by raphe magnus in mammals. This review summarizes the basic concepts of thermoregulation and subsequently assesses the physiological responses to cold stress, including skin blood flow control, sweating, sympathetic-derived cutaneous vasoconstriction and peripheral thermoregulatory control in brown adipose tissue.

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