Cold Acclimation-Associated Changes in Brown Adipose Tissue do Not Necessarily Indicate an Increase of Nonshivering Thermogenesis in C57BL/6J Mice

Talan, Mark I.; Kirov, S. A.; Clow, Lori A; Kosheleva, Nadejda A.

doi:10.1016/s0031-9384(96)00256-9

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…Bat species, experimental group and interaction were used as between‐factor terms, and time was used as within‐factor term. To compensate for possible lack of compound symmetry in the repeated measures anova , Huynh‐Feldt adjustment of the degrees of freedom in the within‐factor (time) analysis was used (Glantz & Slinker 1991; Talan et al . 1996; Zar 1999).…”

Section: Methodsmentioning

confidence: 99%

Differential species‐specific ectoparasitic mite intensities in two intimately coexisting sibling bat species: resource‐mediated host attractiveness or parasite specialization?

Christe

Giorgi

Vogel

et al. 2003

Journal of Animal Ecology

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Summary1. The mechanisms underlying host choice strategies by parasites remain poorly understood. We address two main questions: (i) do parasites prefer vulnerable or well-fed hosts, and (ii) to what extent is a parasite species specialized towards a given host species? 2. To answer these questions, we investigated, both in the field and in the lab, a hostparasite system comprising one ectoparasitic mite ( Spinturnix myoti ) and its major hosts, two sibling species of bats ( Myotis myotis and M. blythii ), which coexist intimately in colonial nursery roosts. We exploited the close physical associations between host species in colonial roosts as well as naturally occurring annual variation in food abundance to investigate the relationships between parasite intensities and (i) host species and (ii) individual nutritional status. 3. Although horizontal transmission of parasites was facilitated by the intimate aggregation of bats within their colonial clusters, we found significant interspecific differences in degree of infestation throughout the 6 years of the study, with M. myotis always more heavily parasitized than M. blythii . This pattern was replicated in a laboratory experiment in which any species-specific resistance induced by exploitation of different trophic niches in nature was removed. 4. Within both host species, S. myoti showed a clear preference for individuals with higher nutritional status. In years with high resource abundance, both bat hosts harboured more parasites than in low-resource years, although the relative difference in parasite burden across species was maintained. This pattern of host choice was also replicated in the laboratory. When offered a choice, parasites always colonized better-fed individuals. 5. These results show first that host specialization in our study system occurred. Second, immediate parasite choice clearly operated towards the selection of hosts in good nutritional state.

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Section: Methodsmentioning

confidence: 99%

Differential species‐specific ectoparasitic mite intensities in two intimately coexisting sibling bat species: resource‐mediated host attractiveness or parasite specialization?

Christe

Giorgi

Vogel

et al. 2003

Journal of Animal Ecology

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“…For such response, the circadian system is important. To support this result, the expression of uncoupling protein 1 (UCP1) mRNA [45][46][47] in the interscapular brown adipose tissue (iBAT, one of the effector organs for thermoregulatory heat production)…”

Section: Role Of the Circadian System And Associated Brain Areas In Cmentioning

confidence: 99%

Circadian Body Temperature Rhythm and the Interaction with Energy State

Nagashima¹,

Tokizawa²,

Marui³

et al. 2019

Homeostasis - An Integrated Vision

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We have revealed that circadian body temperature (T b) rhythm is significantly influenced by fasting/fasting-related hormones. The effect of circadian mechanism and fasting/fasting-related hormones on thermoregulation was examined. Fasting decreases T b during the light phase in rodents. For the regulation, the suprachiasmatic nucleus (SCN) and clock genes, such as Cry and Clock, are necessary. In addition, ghrelin and several hypothalamic nuclei, that is, the medial preoptic area, paraventricular nucleus (PVN), and arcuate nucleus (ARC), play a key role in the T b rhythm. During the light phase, fasting and ghrelin affect the hypothalamic areas. The activity of the SCN increases and that of the ARC decreases. The SCN sends inhibitory signals to the PVN, which may result in a lower heat production in the interscapular brown adipose tissue (iBAT) and T b. By contrast, during the dark phase, the activity of the SCN decreases and that of the ARC increases. The inhibitory signal from the SCN is less, and the PVN is activated. Heat production of the iBAT increases and T b is maintained. There are functional and anatomical connections between the circadian and thermoregulation systems. The circadian system modulates thermoregulatory response to hypothermia and/or cold depending on time and feeding condition.

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“…It is therefore interesting that the reduction in BAT mass and thermogenin was not accompanied by a reduced thermogenic capacity, which, in fact, we found to be unaltered in the prenatal-hypoxia group and increased in the postnatalhypoxia group. Previously, in mice chronically exposed to cold, it was noticed that the characteristic increases in BAT mass and thermogenin were not necessarily parallelled by an increase in the V O 2 response to cold (32). A mismatch between anatomic and biochemical changes of BAT and whole-organism thermogenic capacity reflects the multifaceted action of a prolonged stimulus.…”

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confidence: 99%

Thermogenesis in newborn rats after prenatal or postnatal hypoxia

Mortola

Naso

1998

Journal of Applied Physiology

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Oxygen consumption (VO2) was measured in normoxia as ambient temperature (Ta) was lowered from 40 to 15 degrees C, at the rate of 0.5 degrees C/min (thermoneutrality approximately 33 degrees C). In 2-day-old rats born in hypoxia after hypoxic gestation, the Ta-VO2 relationship was as in controls; their interscapular brown adipose tissue (IBAT) was hypoplastic (less proteins and DNA), with lower concentration of the mitochondrial uncoupling protein thermogenin. In 8-day-old rats exposed to hypoxia postnatally (day 2 to day 8), at any Ta below thermoneutrality VO2 was higher than in controls; also, in this group IBAT was hypoplastic with decreased thermogenin. Additional measurements under various experimental conditions indicated that the increased thermogenic capacity was not explained by the smaller body mass and increased blood oxygen content or by the eventuality of intermittent cold stimuli during the chronic hypoxia. On the other hand, chronic hypercapnia (3% CO2 in normoxia, from day 2 to day 8) also resulted in increased normoxic thermogenesis. We conclude that chronic hypoxia in the perinatal period 1) reduces IBAT mass and thermogenin concentration and 2) can increase the newborn's thermogenic capacity because of stress-related mechanisms not specific to hypoxia.

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Cold Acclimation-Associated Changes in Brown Adipose Tissue do Not Necessarily Indicate an Increase of Nonshivering Thermogenesis in C57BL/6J Mice

Cited by 4 publications

References 23 publications

Differential species‐specific ectoparasitic mite intensities in two intimately coexisting sibling bat species: resource‐mediated host attractiveness or parasite specialization?

Differential species‐specific ectoparasitic mite intensities in two intimately coexisting sibling bat species: resource‐mediated host attractiveness or parasite specialization?

Circadian Body Temperature Rhythm and the Interaction with Energy State

Thermogenesis in newborn rats after prenatal or postnatal hypoxia

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