Day—Night changes of body temperature and feeding activity in heat-acclimated rats

Shido, Osamu; Sakurada, Sotaro; Kohda, Wataru; Nagasaka, Tetsuo

doi:10.1016/0031-9384(94)90082-5

Cited by 27 publications

(22 citation statements)

References 21 publications

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“…The present findings confirmed previous observations, which showed that in rats subjected to daily heat exposure for about 5 h limited to a fixed time, T cor fell, especially during the same period as that during which they had been previously exposed to heat [1][2][3]. Such a fall in T cor observed around the period of the previous heat exposure period was consistent even when daily heat exposure was limited to about 1.5 and 3 h. It was therefore suggested that a time memory for heat exposure in rats could be formed when the duration of each heat exposure was relatively short, and that the period of hypothermia induced by repeated daily heat exposure depended on the duration of timed daily heat exposure.…”

supporting

confidence: 93%

“…limited to about 5 h at a fixed time of the day, then transferred to a constant thermoneutral ambient temperature (T a ), the pattern of nycthemeral variations in their core temperature (T cor ) was altered so that T cor fell significantly for 3 to 4 h during the period when they had previously been exposed to heat [1][2][3]. The newly established pattern of the T cor cycle persisted for 1, 3, and 6 d after the repetition of timed daily heat exposure for 5, 14, and 28 consecutive days, respectively, with no actual temperature stimuli [2].…”

mentioning

confidence: 99%

“…The fall in T cor in rats exposed to repeated daily heat exposure has been shown to be associated with reductions in spontaneous thermogenic behaviors, such as feeding and locomotor activities [3]. The behavioral changes should contribute to the maintenance of T cor at a low level by depressing metabolic heat production.…”

mentioning

confidence: 99%

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Anticipatory Fall in Core Temperature in Rats Acclimated to Heat Given for Various Hours at a Fixed Daily Time.

Hara

Yamasaki²,

Hashimoto³

et al. 2001

JJP

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supporting

confidence: 93%

mentioning

confidence: 99%

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Anticipatory Fall in Core Temperature in Rats Acclimated to Heat Given for Various Hours at a Fixed Daily Time.

Hara

Yamasaki²,

Hashimoto³

et al. 2001

JJP

Self Cite

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“…As no direct evidence for heat acclimation was taken in the present study, we are cautious to claim that our results relate to a heat exposure protocol and not heat acclimation per se. The heat exposure protocol adopted, however, is similar to others that have shown evidence for heat acclimation (Shido et al 1991(Shido et al , 1994 and we believe it is likely that a level of heat acclimation occurred.…”

Section: Discussionmentioning

confidence: 81%

“…Similar heat exposure protocols elicit evidence of heat acclimation in rats (e.g. Shido et al 1994;Shido et al 1991). At all other times animals were kept at 20°C.…”

Section: Methodsmentioning

confidence: 99%

Heat exposure does not alter eccentric exercise-induced increases in mitochondrial calcium and respiratory dysfunction

et al. 2011

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Eccentric exercise can lead to muscle damage including dramatic changes to mitochondrial calcium content (MCC) and impaired respiratory function. Heat acclimation can create a cross-tolerance to a number of stresses including eccentric exercise but little is known about any protection to mitochondria. We hypothesised that intermittent heat exposure will lead to improved control of MCC and to preserved mitochondrial function following eccentric exercise. Sprague-Dawley rats were exposed to 3 weeks of intermittent heat exposure (36°C, 40% relative humidity, 6 h/day, 5 days a week) or kept in cool conditions (20°C). Animals were then assigned to a control or exercise group (-14°C decline treadmill exercise for 90 min). MCC, mitochondrial respiration and mitochondrial permeability transition pore opening (mPTP) were measured in mitochondria isolated from the red quadriceps in animals killed immediately, 2 h and 48 h post-exercise. Results showed that heat exposure was associated with lower plasma creatine kinase levels (p < 0.05) post-exercise suggesting lower levels of muscle damage. There was a significant (~500%) rise in MCC (p < 0.001) and a reduction in mitochondrial respiratory control ratio (p < 0.001) 48 h post-exercise. mPTP displayed increased (p < 0.05) sensitivity to calcium immediately and 48 h post-exercise. Thus, decline running led to significant impairment of mitochondria respiration and calcium loading which was more pronounced 48 h post-exercise compared with earlier time points. MCC levels and mitochondrial function were not altered by heat exposure. In conclusion, intermittent heat exposure does not appear to provide protection against mitochondrial dysfunction resulting from eccentric exercise.

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Integration of Biological Clocks and Rhythms

Refinetti

2012

Comprehensive Physiology

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Animals, plants, and microorganisms exhibit numerous biological rhythms that are generated by numerous biological clocks. This article summarizes experimental data pertinent to the often-ignored issue of integration of multiple rhythms. Five contexts of integration are discussed: (i) integration of circadian rhythms of multiple processes within an individual organism, (ii) integration of biological rhythms operating in different time scales (such as tidal, daily, and seasonal), (iii) integration of rhythms across multiple species, (iv) integration of rhythms of different members of a species, and (v) integration of rhythmicity and physiological homeostasis. Understanding of these multiple rhythmic interactions is an important first step in the eventual thorough understanding of how organisms arrange their vital functions temporally within and without their bodies.

show abstract

Day—Night changes of body temperature and feeding activity in heat-acclimated rats

Cited by 27 publications

References 21 publications

Anticipatory Fall in Core Temperature in Rats Acclimated to Heat Given for Various Hours at a Fixed Daily Time.

Anticipatory Fall in Core Temperature in Rats Acclimated to Heat Given for Various Hours at a Fixed Daily Time.

Heat exposure does not alter eccentric exercise-induced increases in mitochondrial calcium and respiratory dysfunction

Integration of Biological Clocks and Rhythms

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