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Author Jan Stenvers, D.; van Dorp, R.; Foppen, E.; Mendoza, J.; Opperhuizen, A.-L.; Fliers, E.; Bisschop, P.H.; Meijer, J.H.; Kalsbeek, A.; Deboer, T.
Title Dim light at night disturbs the daily sleep-wake cycle in the rat Type Journal Article
Year 2016 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 6 Issue Pages (down) 35662
Keywords Animals
Abstract Exposure to light at night (LAN) is associated with insomnia in humans. Light provides the main input to the master clock in the hypothalamic suprachiasmatic nucleus (SCN) that coordinates the sleep-wake cycle. We aimed to develop a rodent model for the effects of LAN on sleep. Therefore, we exposed male Wistar rats to either a 12 h light (150-200lux):12 h dark (LD) schedule or a 12 h light (150-200 lux):12 h dim white light (5 lux) (LDim) schedule. LDim acutely decreased the amplitude of daily rhythms of REM and NREM sleep, with a further decrease over the following days. LDim diminished the rhythms of 1) the circadian 16-19 Hz frequency domain within the NREM sleep EEG, and 2) SCN clock gene expression. LDim also induced internal desynchronization in locomotor activity by introducing a free running rhythm with a period of ~25 h next to the entrained 24 h rhythm. LDim did not affect body weight or glucose tolerance. In conclusion, we introduce the first rodent model for disturbed circadian control of sleep due to LAN. We show that internal desynchronization is possible in a 24 h L:D cycle which suggests that a similar desynchronization may explain the association between LAN and human insomnia.
Address Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:27762290 Approved no
Call Number LoNNe @ kyba @ Serial 1547
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Author Raap, T.; Casasole, G.; Costantini, D.; AbdElgawad, H.; Asard, H.; Pinxten, R.; Eens, M.
Title Artificial light at night affects body mass but not oxidative status in free-living nestling songbirds: an experimental study Type Journal Article
Year 2016 Publication Scientific Reports Abbreviated Journal Sci. Rep.
Volume 6 Issue Pages (down) 35626
Keywords Animals
Abstract Artificial light at night (ALAN), termed light pollution, is an increasingly important anthropogenic environmental pressure on wildlife. Exposure to unnatural lighting environments may have profound effects on animal physiology, particularly during early life. Here, we experimentally investigated for the first time the impact of ALAN on body mass and oxidative status during development, using nestlings of a free-living songbird, the great tit (Parus major), an important model species. Body mass and blood oxidative status were determined at baseline (=13 days after hatching) and again after a two night exposure to ALAN. Because it is very difficult to generalise the oxidative status from one or two measures we relied on a multi-biomarker approach. We determined multiple metrics of both antioxidant defences and oxidative damage: molecular antioxidants GSH, GSSG; antioxidant enzymes GPX, SOD, CAT; total non-enzymatic antioxidant capacity and damage markers protein carbonyls and TBARS. Light exposed nestlings showed no increase in body mass, in contrast to unexposed individuals. None of the metrics of oxidative status were affected. Nonetheless, our study provides experimental field evidence that ALAN may negatively affect free-living nestlings’ development and hence may have adverse consequences lasting throughout adulthood.
Address
Corporate Author Thesis
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1543
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Author Flores, D.E.F.L.; Jannetti, M.G.; Valentinuzzi, V.S.; Oda, G.A.
Title Entrainment of circadian rhythms to irregular light/dark cycles: a subterranean perspective Type Journal Article
Year 2016 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 6 Issue Pages (down) 34264
Keywords Animals
Abstract Synchronization of biological rhythms to the 24-hour day/night has long been studied with model organisms, under artificial light/dark cycles in the laboratory. The commonly used rectangular light/dark cycles, comprising hours of continuous light and darkness, may not be representative of the natural light exposure for most species, including humans. Subterranean rodents live in dark underground tunnels and offer a unique opportunity to investigate extreme mechanisms of photic entrainment in the wild. Here, we show automated field recordings of the daily light exposure patterns in a South American subterranean rodent, the tuco-tuco (Ctenomys aff. knighti ). In the laboratory, we exposed tuco-tucos to a simplified version of this natural light exposure pattern, to determine the minimum light timing information that is necessary for synchronization. As predicted from our previous studies using mathematical modeling, the activity rhythm of tuco-tucos synchronized to this mostly simplified light/dark regimen consisting of a single light pulse per day, occurring at randomly scattered times within a day length interval. Our integrated semi-natural, lab and computer simulation findings indicate that photic entrainment of circadian oscillators is robust, even in face of artificially reduced exposure and increased phase instability of the synchronizing stimuli.
Address Institute of Biosciences, Department of Physiology, University of Sao Paulo; Sao Paulo, Sao Paulo, 05508-900; Brazil
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:27698436 Approved no
Call Number LoNNe @ kyba @ Serial 1539
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Author Cho, C.-H.; Moon, J.-H.; Yoon, H.-K.; Kang, S.-G.; Geum, D.; Son, G.-H.; Lim, J.-M.; Kim, L.; Lee, E.-I.; Lee, H.-J.
Title Molecular circadian rhythm shift due to bright light exposure before bedtime is related to subthreshold bipolarity Type Journal Article
Year 2016 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 6 Issue Pages (down) 31846
Keywords Human Health
Abstract This study examined the link between circadian rhythm changes due to bright light exposure and subthreshold bipolarity. Molecular circadian rhythms, polysomnography, and actigraphy data were studied in 25 young, healthy male subjects, divided into high and low mood disorder questionnaire (MDQ) score groups. During the first 2 days of the study, the subjects were exposed to daily-living light (150 lux) for 4 hours before bedtime. Saliva and buccal cells were collected 5 times a day for 2 consecutive days. During the subsequent 5 days, the subjects were exposed to bright light (1,000 lux), and saliva and buccal cell samples were collected in the same way. Molecular circadian rhythms were analyzed using sine regression. Circadian rhythms of cortisol (F = 16.956, p < 0.001) and relative PER1/ARNTL gene expression (F = 122.1, p < 0.001) showed a delayed acrophase in both groups after bright light exposure. The high MDQ score group showed a significant delay in acrophase compared to the low MDQ score group only in salivary cortisol (F = 8.528, p = 0.008). The high MDQ score group showed hypersensitivity in cortisol rhythm shift after bright light exposure, suggesting characteristic molecular circadian rhythm changes in the high MDQ score group may be related to biological processes downstream from core circadian clock gene expression.
Address Department of Biomedical Science, Korea University College of Medicine, Seoul, South Korea
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:27545669 Approved no
Call Number LoNNe @ kyba @ Serial 1513
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Author Spitschan, M.; Aguirre, G.K.; Brainard, D.H.; Sweeney, A.M.
Title Variation of outdoor illumination as a function of solar elevation and light pollution Type Journal Article
Year 2016 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 6 Issue Pages (down) 26756
Keywords Skyglow; Measurements; light pollution; daylight; twilight; sky brightness; spectral irradiance; CIE
Abstract The illumination of the environment undergoes both intensity and spectral changes during the 24 h cycle of a day. Daylight spectral power distributions are well described by low-dimensional models such as the CIE (Commission Internationale de l'Eclairage) daylight model, but the performance of this model in non-daylight regimes is not characterised. We measured downwelling spectral irradiance across multiple days in two locations in North America: One rural location (Cherry Springs State Park, PA) with minimal anthropogenic light sources, and one city location (Philadelphia, PA). We characterise the spectral, intensity and colour changes and extend the existing CIE model for daylight to capture twilight components and the spectrum of the night sky.
Address Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
Corporate Author Thesis
Publisher Nature Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:27272736 Approved no
Call Number IDA @ john @ Serial 1464
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