Disruption of circadian rhythms due to chronic constant light leads to depressive and anxiety-like behaviors in the rat

2013 ◽  
Vol 252 ◽  
pp. 1-9 ◽  
Author(s):  
Araceli Tapia-Osorio ◽  
Roberto Salgado-Delgado ◽  
Manuel Angeles-Castellanos ◽  
Carolina Escobar
Keyword(s):  
Circadian Rhythms ◽  
Constant Light

Photic Response Parameters of Circadian Rhythms in The Spinifex Hopping Mouse, Notomys alexis.

1996 ◽  
Vol 19 (1) ◽  
pp. 11
Author(s):  
A.J.P. Francis ◽  
G.J. Coleman
Keyword(s):  
Circadian Rhythms ◽  
Phase Relations ◽  
Constant Light ◽  
Constant Darkness ◽  
Biological Clocks ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Controlled Conditions ◽  
Australian Native Rodent ◽  
Photic Response

Circadian rhythms are generated endogenously by biological clocks or 'pacemakers', which are responsive to significant environmental stimuli termed zeitgebers. Interactions between pacemakers and zeitgebers provide the basis for synchronisation by light-dark (LD) cycles, and the characteristics of each of these elements determines the phase-relations maintained between an animal's circadian activity rhythms and the natural temporal environment. We report here the basic photic response parameters for an Australian native rodent, Notomys alexis. Under controlled conditions of constant darkness or constant light, N. alexis were found to 'free-run', and with periods different from 24 hours. Under LD cycles N. alexis were strictly nocturnal although, compared to other rodents, entrainment to LD cycles was relatively unstable. This may indicate that N. alexis are not strongly dependent on the LD cycle as a zeitgeber.

Monosodium glutamate modulates the circadian rhythms of biochemical variables and behavioral activity in rats under constant light

2012 ◽  
Vol 2 (3) ◽  
pp. 251 ◽  
Author(s):  
Perumal Subramanian ◽  
Selvaraju Subash ◽  
Natarajan Murugan ◽  
Palanisamy Kumaravel ◽  
KrishnamoorthySwarnam Seethalakshmi ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Monosodium Glutamate ◽  
Constant Light ◽  
Behavioral Activity ◽  
Biochemical Variables

scholarly journals The effects of Levilactobacillus brevis on the physiological parameters and gut microbiota composition of rats subjected to desynchronosis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Evgenii I. Olekhnovich ◽  
Ekaterina G. Batotsyrenova ◽  
Roman A. Yunes ◽  
Vadim A. Kashuro ◽  
Elena U. Poluektova ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Gut Microbiota ◽  
Relative Abundance ◽  
Reduced Glutathione ◽  
Physiological Parameters ◽  
Male Rats ◽  
Constant Light ◽  
Constant Darkness ◽  
Microbiota Composition ◽  
Gut Microbiota Composition

Abstract Background All living organisms have developed during evolution complex time-keeping biological clocks that allowed them to stay attuned to their environments. Circadian rhythms cycle on a near 24 h clock. These encompass a variety of changes in the body ranging from blood hormone levels to metabolism, to the gut microbiota composition and others. The gut microbiota, in return, influences the host stress response and the physiological changes associated with it, which makes it an important determinant of health. Lactobacilli are traditionally consumed for their prophylactic and therapeutic benefits against various diseases, namely, the inflammatory bowel syndrome, and even emerged recently as promising psychobiotics. However, the potential role of lactobacilli in the normalization of circadian rhythms has not been addressed. Results Two-month-old male rats were randomly divided into three groups and housed under three different light/dark cycles for three months: natural light, constant light and constant darkness. The strain Levilactobacillus brevis 47f was administered to rats at a dose of 0.5 ml per rat for one month and The rats were observed for the following two months. As a result, we identified the biomarkers associated with intake of L. brevis 47f. Changing the light regime for three months depleted the reserves of the main buffer in the cell—reduced glutathione. Intake of L. brevis 47f for 30 days restored cellular reserves of reduced glutathione and promoted redox balance. Our results indicate that the levels of urinary catecholamines correlated with light/dark cycles and were influenced by intake of L. brevis 47f. The gut microbiota of rats was also influenced by these factors. L. brevis 47f intake was associated with an increase in the relative abundance of Faecalibacterium and Roseburia and a decrease in the relative abundance of Prevotella and Bacteroides. Conclusions The results of this study show that oral administration of L. brevis 47f, for one month, to rats housed under abnormal lightning conditions (constant light or constant darkness) normalized their physiological parameters and promoted the gut microbiome's balance.

scholarly journals Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels

2011 ◽  
Vol 8 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Cory T. Williams ◽  
Brian M. Barnes ◽  
C. Loren Buck
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Ground Squirrels ◽  
The Arctic ◽  
Constant Light ◽  
Polar Regions ◽  
Free Living ◽  
Active Season ◽  
Temperature Rhythms ◽  
Arctic Ground Squirrels

In indigenous arctic reindeer and ptarmigan, circadian rhythms are not expressed during the constant light of summer or constant dark of winter, and it has been hypothesized that a seasonal absence of circadian rhythms is common to all vertebrate residents of polar regions. Here, we show that, while free-living arctic ground squirrels do not express circadian rhythms during the heterothermic and pre-emergent euthermic intervals of hibernation, they display entrained daily rhythms of body temperature ( T b ) throughout their active season, which includes six weeks of constant sun. In winter, ground squirrels are arrhythmic and regulate core body temperatures to within ±0.2°C for up to 18 days during steady-state torpor. In spring, after the use of torpor ends, male but not female ground squirrels, resume euthermic levels of T b in their dark burrows but remain arrhythmic for up to 27 days. However, once activity on the surface begins, both sexes exhibit robust 24 h cycles of body temperature. We suggest that persistence of nycthemeral rhythms through the polar summer enables ground squirrels to minimize thermoregulatory costs. However, the environmental cues (zeitgebers) used to entrain rhythms during the constant light of the arctic summer in these semi-fossorial rodents are unknown.

Continuous light or darkness and circadian periodic mitosis and metabolism in C and D8 mice

1961 ◽  
Vol 201 (2) ◽  
pp. 227-230 ◽  
Author(s):  
Franz Halberg ◽  
Cyrus P. Barnum
Keyword(s):  
Cell Division ◽  
Circadian Rhythms ◽  
Deoxyribonucleic Acid ◽  
Acid Metabolism ◽  
Specific Activity ◽  
Continuous Light ◽  
Liver Parenchyma ◽  
Constant Light ◽  
Constant Darkness ◽  
Spot Check

In immature C mice exposed first to alternating 12 hr of light and 12 hr of darkness (LD), and maintained thereafter in constant darkness for several days, the circadian rhythms in hepatic and pinnal mitosis are demonstrable by spot checks made at the approximate times of LD-synchronized peak and trough. Spot checks at same times in mice of same stock and age, kept for several days in constant light, reveal the cell division rhythm of liver parenchyma, but not that of pinnal epidermis. In immature D8 mice kept for several days in constant darkness, rhythms in hepatic mitosis, phospholipid, ribonucleic and deoxyribonucleic acid metabolism persist, while cell division rhythm in ear pinna of same animals is not detectable with the particular spot check used. In mice of same stock and age, on the 4th day in constant light, a significant rhythm persists in the relative specific activity of the hepatic phospholipid; timing of this metabolic cellular rhythm is drastically desynchronized from the reference standard of a 24-hr clock. Data reveal persistence of some mitotic and metabolic circadian rhythms under conditions studied, with phase drifts or phase shifts of these rhythms occurring both in relation to the 24-hr clock and among the rhythms themselves. These changes in external and internal timing of a circadian system are more extensive in constant light than in constant darkness.

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