Brown Fat: Thermogenic Effect during Arousal from Hibernation in the Bat

Smalley, Robert L.; Dryer, Robert L.

doi:10.1126/science.140.3573.1333

Cited by 155 publications

(26 citation statements)

References 4 publications

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“…Zirm (1956) found that after excision of 50 % of the brown adipose tissue hedgehogs died during hibernation if exposed to very low environmental temperatures. Recently it has been shown that brown adipose tissue in hibernating animals during arousal (Smith & Hock, 1963;Smalley & Dryer, 1963) and in the adult rat on exposure to cold (Donhoffer, Sardy, Szegvari, 1964) is a site of heat production. However, the contribution of brown adipose tissue to the total heat production of either the rat on cold exposure or the hibernating animal during arousal is not known.…”

Section: Discussionmentioning

confidence: 99%

The contribution of brown adipose tissue to heat production in the new‐born rabbit.

Hull¹,

Segall²

1965

The Journal of Physiology

131

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Section: Discussionmentioning

confidence: 99%

The contribution of brown adipose tissue to heat production in the new‐born rabbit.

Hull¹,

Segall²

1965

The Journal of Physiology

131

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“…The importance of BAT thermogenesis produced by norepinephrine when animals arouse from hibernation or recover from severe hypothermia has been extensively discussed (31,32). It has been reported that the ␣ 1 -adrenergic receptor mediates thermogenesis in rats (1) and potentiates ␤ 3 -action (43).…”

Section: In Vivo Experimentsmentioning

confidence: 99%

Increased thermogenic capacity of brown adipose tissue under low temperature and its contribution to arousal from hibernation in Syrian hamsters

Kitao

Hashimoto

2012

American Journal of Physiology-Regulatory, Integrative and Comp

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Kitao N, Hashimoto M. Increased thermogenic capacity of brown adipose tissue under low temperature and its contribution to arousal from hibernation in Syrian hamsters. Am J Physiol Regul Integr Comp Physiol 302: R118 -R125, 2012. First published October 12, 2011 doi:10.1152/ajpregu.00053.2011.-Brown adipose tissue (BAT) is thought to play a significant physiological role during arousal when body temperature rises from the extremely low body temperature that occurs during hibernation. The dominant pathway of BAT thermogenesis occurs through the ␤3-adrenergic receptor. In this study, we investigated the role of the ␤3-adrenergic system in BAT thermogenesis during arousal from hibernation both in vitro and in vivo. Syrian hamsters in the hibernation group contained BAT that was significantly greater in overall mass, total protein, and thermogenic uncoupling protein-1 than BAT from the warm-acclimated group. Although the ability of the ␤3-agonist CL316,243 to induce BAT thermogenesis at 36°C was no different between the hibernation and warm-acclimated groups, its maximum ratio over the basal value at 12°C in the hibernation group was significantly larger than that in the warmacclimated group. Forskolin stimulation at 12°C produced equivalent BAT responses in these two groups. In vivo thermogenesis was assessed with the arousal time determined by the time course of BAT temperature or heart rate. Stimulation of BAT by CL316,243 significantly shortened the time of arousal from hibernation compared with that induced by vehicle alone, and it also induced arousal in deep hibernating animals. The ␤3-antagonist SR59230A inhibited arousal from hibernation either in part or completely. These results suggest that BAT in hibernating animals has potent thermogenic activity with a highly effective ␤3-receptor mechanism at lower temperatures. adaptation; ␤ 3-adrenoceptor mechanism HIBERNATION IS CHARACTERIZED by the depression of energy expenditure and body temperature. Arousing from a hypothermic state requires extensive thermogenesis in the period of a few hours (28), and the mechanism of thermogenesis during this process has been the subject of intense investigation. Increased muscle action potential during arousal from hibernation and lowered arousal rate by curarization suggest that shivering partly but significantly contributes to thermogenesis (12,17,22). It is now widely recognized that brown adipose tissue (BAT) plays a physiologically dominant role in nonshivering thermogenesis (NST) when body temperature rises from an extremely low level during arousal from hibernation (7, 10 -13, 31, 32). Thermogenesis in BAT is physiologically stimulated by norepinephrine released from sympathetic nerve terminals. Transduction of the thermogenic signal occurs mainly through ␤ 3 -adrenergic receptors on the membrane of brown adipocytes and is coupled by adenylyl cyclase activation, resulting in increased cytosolic cAMP levels (44, 45). Increased cAMP then induces hydrolysis of stored triacylglycerol by activating cAMP-dependent PKA....

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“…Since the early 1900s, BAT has been extensively investigated using a range of mammalian hibernators, such as ground squirrels, hamsters, marmots, bats and dormice (e.g. Barger et al, 2006;Burlington et al, 1969;Chaffee et al, 1964Chaffee et al, , 1966Hook and Barron, 1941;Malatesta et al, 2001;Rémillard, 1958;Sheldon, 1924;Smalley and Dryer, 1963;Smith, 1964;Smith and Hock, 1963;Smith and Horwitz, 1969;Wells et al, 1965;Yan et al, 2006). BAT function is uniquely regulated in hibernators through the interplay of ambient temperature (T a ) and body temperature (T b ).…”

Section: Introductionmentioning

confidence: 99%

Nature's fat-burning machine: brown adipose tissue in a hibernating mammal

Ballinger

Andrews

2018

Journal of Experimental Biology

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Brown adipose tissue (BAT) is a unique thermogenic tissue in mammals that rapidly produces heat via nonshivering thermogenesis. Small mammalian hibernators have evolved the greatest capacity for BAT because they use it to rewarm from hypothermic torpor numerous times throughout the hibernation season. Although hibernator BAT physiology has been investigated for decades, recent efforts have been directed toward understanding the molecular underpinnings of BAT regulation and function using a variety of methods, from mitochondrial functional assays to 'omics' approaches. As a result, the inner-workings of hibernator BAT are now being illuminated. In this Review, we discuss recent research progress that has identified players and pathways involved in brown adipocyte differentiation and maturation, as well as those involved in metabolic regulation. The unique phenotype of hibernation, and its reliance on BAT to generate heat to arouse mammals from torpor, has uncovered new molecular mechanisms and potential strategies for biomedical applications.

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Brown Fat: Thermogenic Effect during Arousal from Hibernation in the Bat

Abstract: In the bat Eptesicus fuscus the temperature of brown fat exceeded that of other tissues by about 3 degrees C during the late stages of arousal from hibernation. Heat production seems to be a major function of brown fat in the hibernating mammal.

Cited by 155 publications

References 4 publications

The contribution of brown adipose tissue to heat production in the new‐born rabbit.

The contribution of brown adipose tissue to heat production in the new‐born rabbit.

Increased thermogenic capacity of brown adipose tissue under low temperature and its contribution to arousal from hibernation in Syrian hamsters

Nature's fat-burning machine: brown adipose tissue in a hibernating mammal

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