Adaptive Changes in the Thermogenesis of Rats by Cold Acclimation and Deacclimation.

Hori, Kazuko; Ishigaki, T.; Koyama, Katsuhiro; Kaya, Mehmet; Tsujita, Junzo; Hori, Seiki

doi:10.2170/jjphysiol.48.505

Cited by 18 publications

(21 citation statements)

References 8 publications

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“…The growthrelated gain of body weight was significantly inhibited by cold exposure in the current study. Similar results were also reported elsewhere [2,9]. The inhibition of growth may be closely associated with the stress indicated by the atrophy of the thymus and the hypertrophy ( pϾ0.05) of adrenal observed in the cold-ex-Cold Exposure Changes Muscle Function posed rats.…”

Section: Discussionsupporting

confidence: 88%

“…The inhibition of growth may be closely associated with the stress indicated by the atrophy of the thymus and the hypertrophy ( pϾ0.05) of adrenal observed in the cold-ex-Cold Exposure Changes Muscle Function posed rats. Hori et al [2] suggested that the lower body weight in the cold-exposed rat was caused by a greater thermoregulatory thermogenesis in a cold environment. The increased weight of brown adipose tissue also suggests the enhanced thermogenesis and metabolic rate [23].…”

Section: Discussionmentioning

confidence: 99%

“…Five-week-old male Wistar rats (Kyudo, Kumamoto, Japan) with body weight of 91.3Ϯ4.6 g (meanϮSEM) were used in this investigation. The rats were randomly divided into 2 groups: (1) normal cage control (nϭ10) and (2) cold exposure (nϭ10). Both groups were pair-fed powdered diets (CE-2, Nihon CLEA, Tokyo).…”

Section: Animal Care and Experimental Proceduresmentioning

confidence: 99%

“…

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confidence: 99%

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Effects of Long-Term Cold Exposure on Contractile Properties in Slow- and Fast-Twitch Muscles of Rats.

Nomura¹,

Kawano²,

Kang³

et al. 2002

JJP

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Mechanical properties of skeletal muscles or motor performance in mammals [1][2][3][4][5][6][7][8][9], frogs [10,11], and fishes [12][13][14][15] are influenced by changes in environmental temperatures. For example, the maximum velocity of shortening and the maximum rate of tension development decreased at a low temperature in the soleus and extensor digitorum longus (EDL) muscles of rats [4]. Further, Faulkner et al. [1] reported that the maximum and sustained powers in mice EDL muscle were reduced by 40 and 62%, respectively, at 25°C compared to those at 35°C, though the isometric force remained constant. On the contrary, the maximum tetanic tension of rat soleus and EDL was increased steadily when the temperature was elevated from 6 to 30-38°C [3]. It is also reported that the average absolute force in skinned fibers of both soleus Japanese Journal of Physiology, 52, 85-93, 2002 Key words: cold exposure of rat, soleus, extensor digitorum longus, contractile properties, plasma hormones. Abstract:The effects of 20-week cold exposure on contractile properties of soleus and extensor digitorum longus (EDL) muscles and plasma hormone levels were studied in rats. Twenty male Wistar rats (5 week old) were randomly divided into 2 groups (nϭ10 each): cagecontrol and cold-exposed. The rats in the coldexposed group were immersed in shoulder-deep water (ϳ18°C) for 1 h/d, 5 d/week, for 20 weeks. The temperature and humidity of the animal room with 12:12 h light-dark cycle were maintained at ϳ23°C and 55%, respectively. The rats were pair-fed powdered diets. The electromyogram activities in soleus and EDL were elevated by cold exposure. The body weight and absolute soleus wet weight of the cold-exposed group were significantly less than controls at the end of experiment. The one-half relaxation time and contraction time of EDL were significantly longer in the cold-exposed group than in the control group. The rate of twitch tension development, normalized by the maximum twitch tension, in EDL of the cold-exposed group was less than in the control group. Further, the fatigue resistance of EDL, but not of soleus, in response to train stimulation at 10 Hz was improved by cold exposure. The plasma levels of thyroid hormones, 3,5,3Ј-triiodothyronine and thyroxine, were significantly greater in cold-exposed group. Similar changes were also seen in the plasma catecholamine levels in the cold-exposed group ( pϾ0.05). It is suggested that long-term cold exposure causes a shift of the contractile properties of fast-twitch EDL muscle toward the slow-twitch type. The results also indicated that the characteristics of muscles responded more strongly to an increased activity level than to the elevation of plasma hormones.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Animal Care and Experimental Proceduresmentioning

confidence: 99%

“…

…”

mentioning

confidence: 99%

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Effects of Long-Term Cold Exposure on Contractile Properties in Slow- and Fast-Twitch Muscles of Rats.

Nomura¹,

Kawano²,

Kang³

et al. 2002

JJP

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“…In the present study, significantly elevated levels of NE in the VMH were detected in the 7D, 14D and 28D groups. Experimental observations have indicated that chronic infusion of NE into the VMH increases BAT weight (Cincotta et al, 2000), and development of BAT thermogenesis (Himms-Hagen, 1984) and masses (Hori et al, 1998) were observed after several weeks of cold exposure in rats. Thus, activation of neurons in the VMH seems to require a few weeks of cold exposure, and NE in this region may be associated with enhancement of activity of BAT thermogenesis.…”

Section: Article In Pressmentioning

confidence: 99%

Changes in monoamines in rat hypothalamus during cold acclimation

Saito

Ishiwata

Hasegawa

et al. 2005

Journal of Thermal Biology

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Tail position affects the body temperature of rats during cold exposure in a low-energy state

et al. 2011

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Rats place their tails underneath their body trunks when cold (tail-hiding behavior). The aim of the present study was to determine whether this behavior is necessary to maintain body temperature. Male Wistar rats were divided into 'fed' and '42-h fasting' groups. A one-piece tail holder (8.4 cm in length) that prevented the tail-hiding behavior or a three-piece tail holder (2.8 cm in length) that allowed for the tail-hiding behavior was attached to the tails of the rats. The rats were exposed to 27°C for 180 min or to 20°C for 90 min followed by 15°C for 90 min with continuous body temperature and oxygen consumption measurements. Body temperature decreased by -1.0 ± 0.1°C at 15°C only in the rats that prevented tail-hiding behavior of the 42-h fasting group, and oxygen consumption increased at 15°C in all animals. Oxygen consumption was not different between the rats that prevented tail-hiding behavior and the rats that allowed the behavior in the fed and 42-h fasting groups under ambient conditions. These results show that the tail-hiding behavior is involved in thermoregulation in the cold in fasting rats.

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Adaptive Changes in the Thermogenesis of Rats by Cold Acclimation and Deacclimation.

Cited by 18 publications

References 8 publications

Effects of Long-Term Cold Exposure on Contractile Properties in Slow- and Fast-Twitch Muscles of Rats.

Effects of Long-Term Cold Exposure on Contractile Properties in Slow- and Fast-Twitch Muscles of Rats.

Changes in monoamines in rat hypothalamus during cold acclimation

Tail position affects the body temperature of rats during cold exposure in a low-energy state

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