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Author |
Bedrosian, T.A.; Weil, Z.M.; Nelson, R.J. |
Title |
Chronic dim light at night provokes reversible depression-like phenotype: possible role for TNF |
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Journal Article |
Year |
2013 |
Publication |
Molecular Psychiatry |
Abbreviated Journal |
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18 |
Issue |
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Pages |
930-936 |
Keywords |
Animals |
Abstract |
The prevalence of major depression has increased in recent decades and women are twice as likely as men to develop the disorder. Recent environmental changes almost certainly have a role in this phenomenon, but a complete set of contributors remains unspecified. Exposure to artificial light at night (LAN) has surged in prevalence during the past 50 years, coinciding with rising rates of depression. Chronic exposure to LAN is linked to increased risk of breast cancer, obesity and mood disorders, although the relationship to mood is not well characterized. In this study, we investigated the effects of chronic exposure to 5 lux LAN on depression-like behaviors in female hamsters. Using this model, we also characterized hippocampal brain-derived neurotrophic factor expression and hippocampal dendritic morphology, and investigated the reversibility of these changes 1, 2 or 4 weeks following elimination of LAN. Furthermore, we explored the mechanism of action, focusing on hippocampal proinflammatory cytokines given their dual role in synaptic plasticity and the pathogenesis of depression. Using reverse transcription-quantitative PCR, we identified a reversible increase in hippocampal tumor necrosis factor (TNF), but not interleukin-1β, mRNA expression in hamsters exposed to LAN. Direct intracerebroventricular infusion of a dominant-negative inhibitor of soluble TNF, XPro1595, prevented the development of depression-like behavior under LAN, but had no effect on dendritic spine density in the hippocampus. These results indicate a partial role for TNF in the reversible depression-like phenotype observed under chronic dim LAN. Recent environmental changes, such as LAN exposure, may warrant more attention as possible contributors to rising rates of mood disorders. |
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LoNNe @ christopher.kyba @ |
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386 |
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Byrkjedal, I.; Lislevand, T.; Vogler, S. |
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Do passerine birds utilise artificial light to prolong their diurnal activity during winter at northern latitudes? |
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Journal Article |
Year |
2014 |
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Ornis Norvegica |
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37 |
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LoNNe @ christopher.kyba @ |
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387 |
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Einfalt, L.M.; Grace, E.J.; Wahl, D.H. |
Title |
Effects of simulated light intensity, habitat complexity and forage type on predatorâprey interactions in walleye Sander vitreus |
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Journal Article |
Year |
2012 |
Publication |
Ecology of Freshwater Fish |
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21 |
Issue |
4 |
Pages |
560â569 |
Keywords |
Animals; habitat; light intensity; predatorâprey interactions; walleye |
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Predator-prey interactions can be influenced by the behaviour of individual species as well as environmental factors. We conducted laboratory experiments to test for the influences of two abiotic factors (light intensity and habitat complexity) on predatorâprey interactions between walleye Sander vitreus and two prey species, bluegill Lepomis macrochirus and golden shiner Notemigonus crysoleucas. Three light intensities were simulated (day, twilight and night) in the presence or absence of simulated vegetation. Observations of predator behaviour indicated that walleye increased activity and foraging success with decreasing light levels and had most success capturing dispersed, closer prey. While schooling could not be maintained as light levels diminished, prey decreased predation vulnerability by moving into vegetation or higher in the water column. Throughout all treatments, bluegill were more evasive to capture as the number of strikes was similar on both prey but capture rates were higher for golden shiner. Although light intensity and simulated habitat complexity affected predator and prey behaviour, these factors did not interact to influence foraging success of walleye. To fully understand predator and prey behaviours in fishes, an understanding of species-specific responses to abiotic and biotic factors is necessary. |
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LoNNe @ christopher.kyba @ |
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388 |
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Kate, N.N.; Chandrasekhar, M.; Kondam, A.; Kayalvizhi, E.; Suresh, M.; Kavitha, U. |
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A study on effect of altered circadian rhythm in the development of obesity |
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Journal Article |
Year |
2012 |
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Int J Biol Med Res |
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3 |
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2 |
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1595 â 1601 |
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Animals |
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Background: Most living things have a daily cycle that reflects the rising and setting of the sun. A variety of studies have demonstrated that retinal light exposure can increase alertness at night. The global increase in the prevalence of obesity and metabolic disorders coincides with the increase of exposure to light at night (LAN) and shift work. The circadian clock prepares individuals for predictable events such as food availability and sleep, and disruption of clock function causes circadian and metabolic disturbances. Aim: To determine whether a causal relationship exists between night time light exposure behavioral changes and obesity. Methods: In this experiment 18 Swissâalbino male mice were divided into three groups i.e. Continuous light exposure (CL), light at night (LAN), standard (LD) light/dark cycle (control) and the effect of altered circadian rhythm on development of obesity and behavioral changes is seen. The body mass was assessed at the end of eight weeks to find out whether there was any correlation between the three variants. Results: Mice housed in continuous light (CL) or LAN have significantly increased body mass and increased prevalence of day time eating and altered behavioral pattern than mice in a standard (LD) light/dark cycle. Conclusion: These results suggest that light at night disrupt the timing of food intake and other metabolic signals, leading to excess weight gain. Melatonin is vital to this process, mediating the seasonal photoperiodic information through the clock system. Disrupting the melatonin signal or increasing the duration of light leads to changes in metabolism and adiposity consistent with fat storage and insulin resistance. These data are relevant to the coincidence between increasing use of light at night and obesity in humans (night shift worker). |
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LoNNe @ christopher.kyba @ |
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390 |
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La, V.T. |
Title |
Diurnal and Nocturnal Birds Vocalize at Night: A Review. |
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Journal Article |
Year |
2012 |
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The Condor |
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114 |
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245-257 |
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LoNNe @ christopher.kyba @ |
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391 |
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