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Author Bedrosian, T.A. (ed)
Title Circadian Disruption by Light at Night: Implications for Mood Type Book Whole
Year 2013 Publication Abbreviated Journal (up)
Volume Issue Pages
Keywords circadian disruption; sleep; light at night; melanopsin; mood; mental health; Mood Disorders; epigenetics; red light
Abstract Life on Earth has adapted to a consistent 24-h solar cycle. Circadian rhythms in physiology and behavior remain synchronized to the environment using light as the most potent entraining cue. During the past century, however, the widespread adoption of electric light has led to `round-the-clock’ societies. Instead of aligning with the environment, individuals follow artificial and often erratic light cycles created by social and work schedules. In particular, exposure to artificial light at night (LAN), termed “light pollution”, has become pervasive over the past 100 years. Virtually every individual living in the U.S. and Europe experiences this aberrant light exposure, and moreover about 20% of the population performs shift work. LAN may disrupt physiological timekeeping, leading to dysregulation of internal processes and misalignment between behavior and the environment. Recent evidence suggests that individuals exposed to excessive LAN, such as night shift workers, have increased risk for depressive disorders, but the biological mechanism remains unspecified. In mammals, intrinsically photosensitive retinal ganglion cells (ipRGCs) project light information to (1) the suprachiasmatic nucleus (SCN) in the hypothalamus, regulating circadian rhythms, and (2) to limbic regions, putatively regulating mood. Thus, LAN has the potential to affect both circadian timekeeping and mood. In this dissertation, I present evidence from rodent studies supporting the novel hypothesis that night-time exposure to light disrupts circadian organization and contributes to depressed mood. First, I consider the physiological and behavioral consequences associated with unnatural exposure to LAN. The effects of LAN on circadian output are considered in terms of locomotor activity, the diurnal cortisol rhythm, and diurnal clock protein expression in the brain in Chapter 2. The influence of LAN on behavior and brain plasticity is discussed, with particular focus on depressive-like behavior (Chapter 3) and effects of SSRI treatment (Chapter 4). Effects of LAN on structural plasticity and gene expression in the brain are described, with emphasis on potential correlates of the depressive-like behavior observed under LAN in Chapter 5. Given the prevalence of LAN exposure and its importance, strategies for reversing the effects are offered. Specifically, eliminating LAN quickly reverses behavioral and physiological effects of exposure as described in Chapter 5. In Chapter 6 I report that administration of a pharmacological cytokine inhibitor prevents depressive-like behaviors in LAN, implicating brain inflammation in the behavioral effect. Finally, I demonstrate in Chapter 7 that exposure to red wavelength LAN reduces the effects on brain and behavior, suggesting that LAN acts through specific retinal pathways involving melanopsin. Taken together, these studies demonstrate the consequences of LAN, but also outline potential avenues for prevention or intervention.
Address Department of Neuroscience and The Institute for Behavioral Medicine Research The Ohio State University
Corporate Author Thesis Ph.D. thesis
Publisher Place of Publication Editor Bedrosian, T.A.
Language Summary Language Original Title
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Notes Approved no
Call Number IDA @ john @ Serial 323
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Author Fuller, G. (ed)
Title The Night Shift: Lighting and Nocturnal Strepsirrhine Care in Zoos Type Book Whole
Year 2013 Publication Abbreviated Journal (up)
Volume Issue Pages
Keywords zoos; light at night; circadian disruption; strepsirrhines; primates; lorises; pottos; lighting design
Abstract Over billions of years of evolution, light from the sun, moon, and stars has provided

organisms with reliable information about the passage of time. Photic cues entrain

the circadian system, allowing animals to perform behaviors critical for survival and

reproduction at optimal times. Modern artificial lighting has drastically altered

environmental light cues. Evidence is accumulating that exposure to light at night

(particularly blue wavelengths) from computer screens, urban light pollution, or as

an occupational hazard of night-shift work has major implications for human health.

Nocturnal animals are the shift workers of zoos; they are generally housed on

reversed light cycles so that daytime visitors can observe their active behaviors. As a

result, they are exposed to artificial light throughout their subjective night. The goal

of this investigation was to examine critically the care of nocturnal strepsirrhine

primates in North American zoos, focusing on lorises (Loris and Nycticebus spp.) and pottos (Perodicticus potto). The general hypothesis was that exhibit lighting design affects activity patterns and circadian physiology in nocturnal strepsirrhines. The

first specific aim was to assess the status of these populations. A multi-institutional husbandry survey revealed little consensus among zoos in lighting design, with both red and blue light commonly used for nocturnal illumination. A review of medical records also revealed high rates of neonate mortality. The second aim was to

develop methods for measuring the effects of exhibit lighting on behavior and

health. The use of actigraphy for automated activity monitoring was explored.

Methods were also developed for measuring salivary melatonin and cortisol as

indicators of circadian disruption. Finally, a multi-institutional study was conducted

comparing behavioral and endocrine responses to red and blue dark phase lighting.

These results showed greater activity levels in strepsirrhines housed under red light than blue. Salivary melatonin concentrations in pottos suggested that blue light

suppressed nocturnal melatonin production at higher intensities, but evidence for

circadian disruption was equivocal. These results add to the growing body of

evidence on the detrimental effects of blue light at night and are a step towards

empirical recommendations for nocturnal lighting design in zoos.
Address Department of Biology, Case Western Reserve University
Corporate Author Thesis Ph.D. thesis
Publisher Place of Publication Editor Fuller, G.
Language Summary Language Original Title
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Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 327
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Author Anisimov, V.N.; Vinogradova, I.A.; Panchenko, A.V.; Popovich, I.G.; Zabezhinskii, M.A.
Title Light-at-Night-Induced Circadian Disruption, Cancer and Aging Type Journal Article
Year 2012 Publication Current Aging Science Abbreviated Journal (up)
Volume 5 Issue 3 Pages 170-177
Keywords Animals; Light-at-night; aging; cancer; cardiovascular diseases; circadian; circadian rhythm; diabetes; disruption; melatonin; shift-work
Abstract Light-at-night has become an increasing and essential part of the modern lifestyle and leads to a number of health problems, including excessive body mass index, cardiovascular diseases, diabetes, and cancer. The International Agency for Research on Cancer (IARC) Working Group concluded that “shift-work that involves circadian disruption is probably carcinogenic to humans” (Group 2A) [1]. According to the circadian disruption hypothesis, light-at-night might disrupt the endogenous circadian rhythm and specifically suppress nocturnal production of the pineal hormone melatonin and its secretion into the blood. We evaluated the effect of various light/dark regimens on the survival, life span, and spontaneous and chemical carcinogenesis in rodents. Exposure to constant illumination was followed by accelerated aging and enhanced spontaneous tumorigenesis in female CBA and transgenic HER-2/neu mice. In male and female rats maintained at various light/dark regimens (standard 12:12 light/dark [LD], the natural light [NL] of northwestern Russia, constant light [LL], and constant darkness [DD]) from the age of 25 days until natural death, it was found that exposure to NL and LL regimens accelerated age-related switch-off of the estrous function (in females), induced development of metabolic syndrome and spontaneous tumorigenesis, and shortened life span both in male and females rats compared to the standard LD regimen. Melatonin given in nocturnal drinking water prevented the adverse effect of the constant illumination (LL) and natural light (NL) regimens on the homeostasis, life span, and tumor development both in mice and rats. The exposure to the LL regimen accelerated colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in rats, whereas the treatment with melatonin alleviated the effects of LL. The maintenance of rats at the DD regimen inhibited DMH-induced carcinogenesis. The LL regimen accelerated, whereas the DD regimen inhibited both mammary carcinogenesis induced by N-nitrosomethylurea and transplacental carcinogenesis induced by N-nitrosoethylurea in rats. Treatment with melatonin prevented premature aging and tumorigenesis in rodents. The data found in the literature and our observations suggest that the use of melatonin would be effective for cancer prevention in humans at risk as a result of light pollution.
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Call Number LoNNe @ christopher.kyba @ Serial 377
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Author Reiter, R.J.; Rosales-Corral, S.; Coto-Montes, A.; Antonio Boga, J.; Tan, D.X.; Davis, J.M.; Konturek, P.C.; Konturek, S.J.; Brzozowski, T.
Title The photoperiod, circadian regulation and chronodisruption: the requisite interplay between the suprachiasmatic nuclei and the pineal and gut melatonin. Type Journal Article
Year 2011 Publication Journal of Physiology and Pharmacology Abbreviated Journal (up)
Volume 62 Issue Pages 269-274
Keywords Human Health; biological clock; chronodisruption; circadian rhythm; gastrointestinal melatonin; peptic ulcer; pineal gland; suprachiasmatic nucleus
Abstract Biological rhythms are essential for optimal health (1, 2). Throughout the course of human evolution, hominids were exposed to regularly alternating periods of light and dark during every 24-hour period. This evolutionary period, which for humans may have lasted for three million or more years, allowed species to take advantage of the light:dark cycle to adjust their physiology and to synchronize it with the prevailing light:dark environment. To take advantage of this information, vertebrates, including hominids, evolved a group of neurons to monitor the photoperiodic environment and to adjust organismal, organ and cellular function accordingly.

This paired group of light-responsive neurons is located in the mediobasal preoptic area at the diencephalic-telencephalic junction just anterior to the hypothalamus. Since these neurons lie immediately above the decussating axons of the optic nerve, i.e., the optic chiasma, they are named the suprachiasmatic nuclei (SCN) (3, 4). The SCN orchestrate all known circadian rhythms in vertebrates and are referred to as the master biological clock or the central rhythm generator.
Address
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 522
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Author Landgraf, D.; McCarthy, M.J.; Welsh, D.K.
Title The role of the circadian clock in animal models of mood disorders Type Journal Article
Year 2014 Publication Behavioral Neuroscience Abbreviated Journal (up) Behav Neurosci
Volume 128 Issue 3 Pages 344-359
Keywords *Circadian Rhythm; mood; mood disorders; circadian disruption
Abstract An association between circadian clock function and mood regulation is well established and has been proposed as a factor in the development of mood disorders. Patients with depression or mania suffer disturbed sleep-wake cycles and altered rhythms in daily activities. Environmentally disrupted circadian rhythms increase the risk of mood disorders in the general population. However, proof that a disturbance of circadian rhythms is causally involved in the development of psychiatric disorders remains elusive. Using clock gene mutants, manipulations of sleep-wake and light-dark cycles, and brain lesions affecting clock function, animal models have been developed to investigate whether circadian rhythm disruptions alter mood. In this review, selected animal models are examined to address the issue of causality between circadian rhythms and affective behavior.
Address Research Service, Veterans Affairs San Diego Healthcare System
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 0735-7044 ISBN Medium
Area Expedition Conference
Notes PMID:24660657 Approved no
Call Number IDA @ john @ Serial 316
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