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Freeruns
Published in Sue Binkley, Biological Clocks, 2020
In a light–dark cycle, a nocturnal animal, such as a hamster or mouse, is usually active (runs its wheel, eats, mates, etc.) in the dark. When the animals are placed in constant dark (DD), the activity time is usually longer than it is for hamsters placed in constant light.
Role of vitamin B12 on behavioral changes in SHRSP
Published in H. Saito, Y. Yamori, M. Minami, S.H. Parvez, New Advances in SHR Research –, 2020
Masaru Minami, Shin-Ichi Kimura, Ken-Ichi Ueno, Toru Endo, Yoshio Monma, Hiroko Togashi, Machiko Matsumoto, Mitsuhiro Yoshioka, Hideya Saito, Hasan S. Parvez
Activity counts of ambulation in the dark phase were higher than those in the light phase. Thus, a pattern typical of nocturnal animals were observed. With age, 24 h ambulatory activity counts tended to decrease in both WKY and SHRSP. Ambulatory counts of SHRSP were significantly higher than those of WKY at all ages. Figure 1 indicates the change of the ambulatory activity after methylcobalamine administration throughout the life-span of SHRSP. Ambulatory activity of SHRSP was decreased with age. After stroke, the ambulation of SHRSP was increased. However, 24-h ambulatory activity was not different from that of younger age.
What Actually Is Sleep?
Published in Zippi Dolev, Mordechai Zalesch, Judy Kupferman, Sleep and Women's Health, 2019
Zippi Dolev, Mordechai Zalesch, Judy Kupferman
Since life on earth began about 4 billion years ago, plants, animals, and humans have adjusted to the hours of day and night by creating an internal mechanism (biological clock) with electrical activity that has cycles of about 24 hours (circadian) and correlates physiological activities with the daily cycle of day and night. Most of our bodily systems undergo changes during these 24 hours—changes in blood pressure, hormone release, heartbeat, and more. These changes are called circadian rhythms and they include regulation of sleep and wakefulness. Normally, in humans, sleep coincides with nighttime and wakefulness with daytime (Figure 2.3). In nocturnal animals, of course, it is the opposite.
Effect of periodic social interaction and odour presentation of same and opposite-sex conspecifics on free-running mice
Published in Chronobiology International, 2021
Pratishtha Sonker, Rajeev Cherukalady, Muniyandi Singaravel
Circadian rhythms are ~24 h rhythms in physiology and behavior that are generated endogenously and found ubiquitously in a wide variety of organisms (Takahashi 2015). The endogenous circadian rhythm is synchronized by external cyclic cues, resulting in cyclic changes in behavioral and physiological functions (Barak and Kronfeld-Schor 2013). Photic cue such as periodic alteration in the light intensity (Davidson and Menaker 2003), and non-photic cues such as temperature cycles (Buhr et al. 2010), social interactions (Mistlberger and Skene 2004), and the daily cycle of the food availability (Frisch and Aschoff 1987) act as temporal cues to synchronize the phase relationship of endogenous rhythm with the surrounding environment. These environmental cues are also capable to modulate the rhythm of oscillations with or without causing the entrainment, commonly referred to as masking (Aschoff 1960). Masking confines animals to their suitable temporal niche and helps in fine-tuning their activity patterns by regulating the circadian clock (Redlin 2001). Further, light pulse, dark pulse and temperature are often documented for the masking (Aschoff and von Goetz 1989, 1988a; DeCoursey 1960). Diurnal animals are generally more active in response to light whereas nocturnal animals show more activity in response to darkness (Aschoff and von Goetz 1988a; Shuboni et al. 2012). However, only a few studies have examined the effect of social cues on the masking of the circadian rhythm.
Circadian rhythmicity of body temperature and metabolism
Published in Temperature, 2020
Bed rest cannot be used with animals – because they do not comply with requests for voluntary rest – but one can look at the day-night difference in the correlation between the rhythms of activity and temperature. It has been found that, although nocturnal animals are generally more active at night than during the day, their body temperature is higher at night regardless of the actual activity level [628–632]. Conversely, the body temperature of diurnal animals is higher during the day regardless of the actual activity level [306,633]. These relationships are illustrated in Figure 6 for four different species of small mammals. Notice that, for the nocturnal animals (golden hamster and fat-tailed gerbil), body temperature is higher at night for all levels of activity, even though there is a small effect of activity level on body temperature. For the diurnal animals (13-lined ground squirrel and tree shrew), body temperature is higher during the day for all levels of activity [633]. Thus, it can be inferred that the body temperature rhythm in animals, as in humans, is not caused by the activity rhythm. That is, the body temperature rhythm is not a side effect of the metabolism rhythm associated with changes in activity. This conclusion brings us back to the question of whether the body generates (or attempts to generate) a temperature rhythm as a fundamental process of life.
Transcriptional Profiling of Daily Patterns of mRNA Expression in the C57BL/6J Mouse Cornea
Published in Current Eye Research, 2019
Xinwei Jiao, Mingjuan Wu, Dingli Lu, Jianqin Gu, Zhijie Li
We found that most of the rhythm genes in the cornea oscillate with a 24-h period. GO analysis and KEGG enrichment analysis for these cycling genes show that the main pathways and biological processes of these genes are related to the basic activities of corneal cells, such as growth, proliferation, metabolism, and immunity. This conclusion is consistent with a recent study on the diurnal transcriptome of a primate and the nocturnal transcriptome of mice across major neural and peripheral tissues.47 In addition, the peak gene number in the dark cycle is higher than that in the light cycle. This is consistent with the physiological behavior of mice as nocturnal animals,48 characterized by being active at night and sleeping in the day.