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Author Figueiro, M.G.; Rea, M.S.
Title The effects of red and blue lights on circadian variations in cortisol, alpha amylase, and melatonin Type Journal Article
Year 2010 Publication International Journal of Endocrinology Abbreviated Journal Int J Endocrinol
Volume 2010 Issue Pages 829351
Keywords blue light; red light; circadian rhythm; cortisol; alpha amylase; melatonin; photobiology; suprachiasmatic nuclei; endocrinology
Abstract The primary purpose of the present study was to expand our understanding of the impact of light exposures on the endocrine and autonomic systems as measured by acute cortisol, alpha amylase, and melatonin responses. We utilized exposures from narrowband long-wavelength (red) and from narrow-band short-wavelength (blue) lights to more precisely understand the role of the suprachiasmatic nuclei (SCN) in these responses. In a within-subjects experimental design, twelve subjects periodically received one-hour corneal exposures of 40 lux from the blue or from the red lights while continuously awake for 27 hours. Results showed-that, as expected, only the blue light reduced nocturnal melatonin. In contrast, both blue and red lights affected cortisol levels and, although less clear, alpha amylase levels as well. The present data bring into question whether the nonvisual pathway mediating nocturnal melatonin suppression is the same as that mediating other responses to light exhibited by the endocrine and the autonomic nervous systems.
Address Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, 3rd Floor, Troy, New York, NY 12180, USA
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 1687-8337 ISBN Medium
Area Expedition Conference
Notes PMID:20652045; PMCID:PMC2905913 Approved no
Call Number IDA @ john @ Serial 291
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Author Ikeno, T.; Weil, Z.M.; Nelson, R.J.
Title Dim light at night disrupts the short-day response in Siberian hamsters Type Journal Article
Year 2014 Publication General and Comparative Endocrinology Abbreviated Journal Gen Comp Endocrinol
Volume 197 Issue Pages 56-64
Keywords 2,4-dinitro-1-flourobenzene; Dnfb; Dth; Eya3; Eyes absent 3; GnIH; GnRH; Immune function; Ld; Lps; Light pollution; Pt; Pelage; Per1; Period1; Photoperiodism; Rfrp; RFamide-related peptide; Scn; Sd; Seasonality; Tsh; TSH receptor; Tshr; dLAN; delayed-type hypersensitivity; dim light at night; gonadotropin-inhibiting hormone; gonadotropin-releasing hormone; lipopolysaccharide; long days; pars tuberalis; short days; suprachiasmatic nuclei; thyroid-stimulating hormone
Abstract Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response.
Address Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA. Electronic address: randy.nelson@osumc.edu
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 0016-6480 ISBN Medium
Area Expedition Conference
Notes PMID:24362257 Approved no
Call Number IDA @ john @ Serial 82
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Author van Diepen, H.C.; Foster, R.G.; Meijer, J.H.
Title A colourful clock Type Journal Article
Year 2015 Publication PLoS Biology Abbreviated Journal PLoS Biol
Volume 13 Issue 5 Pages e1002160
Keywords Animals; Commentary; *Circadian Rhythm; suprachiasmatic nuclei; melanopsin; retinal ganglion cells; entrainment; photoperiod
Abstract Circadian rhythms are an essential property of life on Earth. In mammals, these rhythms are coordinated by a small set of neurons, located in the suprachiasmatic nuclei (SCN). The environmental light/dark cycle synchronizes (entrains) the SCN via a distinct pathway, originating in a subset of photosensitive retinal ganglion cells (pRGCs) that utilize the photopigment melanopsin (OPN4). The pRGCs are also innervated by rods and cones and, so, are both endogenously and exogenously light sensitive. Accumulating evidence has shown that the circadian system is sensitive to ultraviolet (UV), blue, and green wavelengths of light. However, it was unclear whether colour perception itself can help entrain the SCN. By utilizing both behavioural and electrophysiological recording techniques, Walmsley and colleagues show that multiple photic channels interact and enhance the capacity of the SCN to synchronize to the environmental cycle. Thus, entrainment of the circadian system combines both environmental irradiance and colour information to ensure that internal and external time are appropriately aligned.
Address Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University medical School, Leiden, The Netherlands
Corporate Author Thesis
Publisher PLOS Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1544-9173 ISBN Medium
Area Expedition Conference
Notes PMID:25996907; PMCID:PMC4440787 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 1183
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