Daily restricted feeding resets the circadian clock in the suprachiasmatic nucleus of CS mice

Abe, Hiroshi; Honma, Sato; Honma, Ken‐ichi

doi:10.1152/ajpregu.00331.2006

Cited by 52 publications

(42 citation statements)

References 37 publications

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“…When rodents are subjected to a restricted feeding schedule, the patterns of diurnal variation of various physiological functions change; e.g., locomotory activity and plasma corticosterone levels increase before feeding time [21]. Recent studies have suggested that rhythms of clock gene expression in the SCN show a fixed phase-relationship with feeding time [22,23], indicating that the circadian pacemaker in the SCN can be entrained by the restricted feeding schedule. Thus these observations may support our conclusion that the SCN could form and retain a time memory and work as a timer for changing T cor in rats.…”

Section: Discussionmentioning

confidence: 99%

Contribution of the Suprachiasmatic Nucleus to the Formation of a Time Memory for Heat Exposure in Rats

et al. 2007

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Abstract:We have reported that after rats were acclimated to heat for about 5 h daily at a fixed time, the pattern of day-night variations of core temperature (T cor ) altered, i.e., their T cor fell, especially during the period when they had previously been exposed to heat. The suprachiasmatic nucleus (SCN) of the hypothalamus is known to be indispensable for the genesis of circadian rhythms of T cor . We therefore investigated the involvement of the SCN in the characteristic fall in T cor in heat-acclimated rats. The rats were exposed to an ambient temperature of 33°C only in the last half of the dark phase for 10 consecutive days. After the heat exposure schedule, the nocturnal pattern of T cor variations and Fos expression in the dorsomedial SCN altered so that the T cor and the number of Fos immunoreactive cells decreased in the last half of the dark phase. The bilateral lesions of the SCN of rats were made electrically, and the electrical lesions of the SCNs abolished the daily cycle of T cor . In the SCN-lesioned rats, theT cor levels were significantly lowered after the 10-day heat exposure schedule. However, their T cor did not specifically drop during the period when they had previously been exposed to heat. These findings suggest that the SCN is crucial for establishing a time memory for heat stress, and it plays a minimal role in heat acclimation-induced changes in T cor in rats.Key words: heat acclimation, circadian rhythm, core temperature, suprachiasmatic nucleus Acclimation to heat has been repeatedly shown to alter core temperature (T cor ) levels and to modify autonomic thermoregulatory functions in various species of animals. When rats are subjected to daily heat exposure limited to about 5 h at a fixed time and then transferred to a constant thermoneutral ambient temperature (T a ), the pattern of day-night variations in their T cor alters so that T cor falls for 3 to 4 h around the period when they were previously exposed to heat [1][2][3]. The newly established pattern of the T cor cycle has been shown to persist for 1, 3, and 6 days after the repetition of timed daily heat exposure for 5, 14, and 28 consecutive days, respectively, with no actual temperature stimuli or time cues [2]. Furthermore, heat acclimation-induced changes in thermoregulatory functions, such as downward shifts of thermoeffector thresholds [4], the enhancement of thermoregulatory responses to acute heat load, and reduced resting metabolic rate [5], were clearly seen during the period of the previous heat exposure time. From these observations, we have proposed that a time memory for heat exposure can be formed in rats as a result of repeated heat exposure limited to a fixed time once a day, and according to this memory, thermoregulatory systems may be activated during the specific period so that their heat tolerance improves [6]; however, the central mechanism for the formation and retention of such a time memory is totally unknown.It is well known that the suprachiasmatic nucleus (SCN) of the hypothalamus acts as an ...

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Section: Discussionmentioning

confidence: 99%

Contribution of the Suprachiasmatic Nucleus to the Formation of a Time Memory for Heat Exposure in Rats

et al. 2007

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“…Numerous studies have demonstrated entrainment of animal behavior by daily cycles of food availability in rats [11], mice [12], kowaris [13], sparrows [14], Kuzu rats [15], rabbits [16], squirrel monkeys [17], and other species. Because two separate behavioral components were observed when animals were exposed simultaneously to environmental cycles of light-darkness and food restriction, and because the so-called ''food anticipatory'' component persisted in constant darkness after the main circadian pacemaker in the hypothalamic suprachiasmatic nucleus had been ablated [18], some authors assumed the existence of distinct input pathways to a ''light-entrainable pacemaker'' and a ''food-entrainable pacemaker'' [19].…”

Section: Introductionmentioning

confidence: 99%

Comparison of light, food, and temperature as environmental synchronizers of the circadian rhythm of activity in mice

Refinetti

2015

J Physiol Sci

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Although entrainment (and masking) of circadian rhythms by light has been extensively studied, much less attention has been given to other environmental cycles that can modulate circadian rhythms in mammals. In this study in mice, the entraining strength of different environmental cycles was compared. Running-wheel activity was monitored before, after, and while the animals were under one of four environmental cycles: a full light-dark cycle with 12 h of light and 12 h of darkness each day, a cycle of 1 h of light per day, a cycle of food availability consisting of 80% of the baseline free-feeding amount presented once a day, and an ambient temperature cycle consisting of 23 h at 24 °C and 1 h at 12 °C each day. Four measures of zeitgeber strength were used: percentage of animals that entrained, rhythm robustness in the entrained state, stability of activity onsets, and stability of acrophases. The results indicate that, at least in mice, a full light-dark cycle is the most powerful modulator of the circadian rhythm of locomotor activity, as a consequence of both entrainment and masking. When entrainment alone is considered, temperature seems to be as strong a modulator as light, while food restriction is a weaker modulator and affects primarily a food-anticipatory component of the activity rhythm.

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“…The effects of daytime RF are well documented in the literature in a number of species, including nocturnal rodents, such as Mus musculus and Rattus norvegicus (Abe et al, 1989(Abe et al, , 2007Boulos et al, 1980;Castillo et al, 2004;Challet et al, 1997;Marchant & Mistlberger, 1997;Rosenwasser et al, 1981). Animals adapt to conditions of limited food availability by increasing food-seeking behavior, or FAA, in the hours preceding food presentation.…”

Section: Discussionmentioning

confidence: 99%

Scheduled Feeding Alters the Timing of the Suprachiasmatic Nucleus Circadian Clock in Dexras1-Deficient Mice

Bouchard-Cannon

Cheng

2012

Chronobiology International

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Restricted feeding (RF) schedules are potent zeitgebers capable of entraining metabolic and hormonal rhythms in peripheral oscillators in anticipation of food. Behaviorally, this manifests in the form of food anticipatory activity (FAA) in the hours preceding food availability. Circadian rhythms of FAA are thought to be controlled by a food-entrainable oscillator (FEO) outside of the suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals. Although evidence suggests that the FEO and the SCN are capable of interacting functionally under RF conditions, the genetic basis of these interactions remains to be defined. In this study, using dexras1-deficient (dexras1 −/− ) mice, the authors examined whether Dexras1, a modulator of multiple inputs to the SCN, plays a role in regulating the effects of RF on activity rhythms and gene expression in the SCN. Daytime RF under 12L:12D or constant darkness (DD) resulted in potentiated (but less stable) FAA expression in dexras1 −/− mice compared with wild-type (WT) controls. Under these conditions, the magnitude and phase of the SCN-driven activity component were greatly perturbed in the mutants. Restoration to ad libitum (AL) feeding revealed a stable phase displacement of the SCN-driven activity component of dexras1 −/− mice by ~2 h in advance of the expected time. RF in the late night/early morning induced a long-lasting increase in the period of the SCN-driven activity component in the mutants but not the WT. At the molecular level, daytime RF advanced the rhythm of PER1, PER2, and pERK expression in the mutant SCN without having any effect in the WT. Collectively, these results indicate that the absence of Dexras1 sensitizes the SCN to perturbations resulting from restricted feeding.

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Daily restricted feeding resets the circadian clock in the suprachiasmatic nucleus of CS mice

Cited by 52 publications

References 37 publications

Contribution of the Suprachiasmatic Nucleus to the Formation of a Time Memory for Heat Exposure in Rats

Contribution of the Suprachiasmatic Nucleus to the Formation of a Time Memory for Heat Exposure in Rats

Comparison of light, food, and temperature as environmental synchronizers of the circadian rhythm of activity in mice

Scheduled Feeding Alters the Timing of the Suprachiasmatic Nucleus Circadian Clock in Dexras1-Deficient Mice

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