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Zhang C, Zhu Z, Zhao J, Li Y, Zhang Z, Zheng Y. Ubiquitous light-emitting diodes: Potential threats to retinal circadian rhythms and refractive development. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160809. [PMID: 36502986 DOI: 10.1016/j.scitotenv.2022.160809] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/08/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
The use of light-emitting diodes (LEDs) has increased considerably in the 21st century with humans living in a modern photoperiod with brighter nights and dimmer days. Prolonged exposure to LEDs, especially at night, is considered a new source of pollution because it may affect the synthesis and secretion of retinal melatonin and dopamine, resulting in negative impacts on retinal circadian clocks and potentially disrupting retinal circadian rhythms. The control of ocular refraction is believed to be related to retinal circadian rhythms. Moreover, the global prevalence of myopia has increased at an alarming rate in recent decades. The widespread use of LEDs and the rapid increase in the prevalence of myopia overlap, which is unlikely to be a coincidence. The connection among LEDs, retinal circadian rhythms, and refractive development is both fascinating and confusing. In this review, we aim to develop a systematic framework that includes LEDs, retinal circadian rhythms and refractive development. This paper summarizes the possible mechanisms by which LEDs may disrupt retinal circadian rhythms. We propose that prolonged exposure to LEDs may induce myopia by disrupting retinal circadian rhythms. Finally, we suggest several possible countermeasures to prevent LED interference on retinal circadian rhythms, with the hope of reducing the onset and progression of myopia.
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Affiliation(s)
- Chenchen Zhang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Zhe Zhu
- Department of Ophthalmology, Eye Hospital of Shandong First Medical University, Shandong Eye Institute, Jinan 250000, China
| | - Jing Zhao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Yanxia Li
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Zhaoying Zhang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Yajuan Zheng
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China.
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2
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Ziólkowska N, Chmielewska-Krzesinska M, Vyniarska A, Sienkiewicz W. Exposure to Blue Light Reduces Melanopsin Expression in Intrinsically Photoreceptive Retinal Ganglion Cells and Damages the Inner Retina in Rats. Invest Ophthalmol Vis Sci 2022; 63:26. [PMID: 35060997 PMCID: PMC8787613 DOI: 10.1167/iovs.63.1.26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Purpose The purpose of this study was to investigative the effects of blue light on intrinsically photoreceptive retinal ganglion cells (ipRGCs). Methods Brown Norway rats were used. Nine rats were continuously exposed to blue light (light emitting diodes [LEDs]: 463 nm; 1000 lx) for 2 days (acute exposure [AE]); 9 rats were exposed to 12 hours of blue light and 12 hours of darkness for 10 days (long-term exposure [LTE]); 6 control rats were exposed to 12 hours of white fluorescent light (1000 lx) and 12 hours of darkness for 10 days. Whole-mount retinas were immunolabelled with melanopsin antibodies; melanopsin-positive (MP) ipRGC somas and processes were counted and measured with Neuron J. To detect apoptosis, retinal cryo-sections were stained with terminal deoxynucleotidyl transferase dUTP nick-end labeling. Ultra-thin sections were visualized with transmission electron microscopy. Results The number of MP ipRGC somas was significantly lower in retinas from AE and LTE rats than in those from control rats (P < 0.001 and = 0.002, respectively). The mean length of MP areas of processes was significantly lower in AE rats (P < 0.001). AE rats had severe retinal damage and massive apoptosis in the outer nuclear layer; their mitochondria were damaged in the axons and dendrites of the nerve fiber layer and the inner plexiform layer. Retinal ganglion cells (RGCs) in AE rats appeared to have reduced amounts of free ribosomes and rough endoplasmic reticulum. Conclusions AE to blue light reduces melanopsin expression and damages RGCs, likely including ipRGCs. Changes in the axons and dendrites of RGCs suggest possible disruption of intraretinal and extraretinal signal transmission.
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Affiliation(s)
- Natalia Ziólkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Malgorzata Chmielewska-Krzesinska
- Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Alla Vyniarska
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Stepan Gzhytskyi National University of Veterinary and Biotechnologies, Lviv, Ukraine
| | - Waldemar Sienkiewicz
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
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3
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Markwell EL, Feigl B, Zele AJ. Intrinsically photosensitive melanopsin retinal ganglion cell contributions to the pupillary light reflex and circadian rhythm. Clin Exp Optom 2021; 93:137-49. [DOI: 10.1111/j.1444-0938.2010.00479.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Emma L Markwell
- Visual Science and Medical Retina Laboratory, Institute of Health and Biomedical Innovation and School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia
E‐mail:
| | - Beatrix Feigl
- Visual Science and Medical Retina Laboratory, Institute of Health and Biomedical Innovation and School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia
E‐mail:
| | - Andrew J Zele
- Visual Science and Medical Retina Laboratory, Institute of Health and Biomedical Innovation and School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia
E‐mail:
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4
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Meng Q, Jiang J, Hou X, Jia L, Duan X, Zhou W, Zhang Q, Cheng Z, Wang S, Xiao Q, Wei X, Hao W. Antidepressant Effect of Blue Light on Depressive Phenotype in Light-Deprived Male Rats. J Neuropathol Exp Neurol 2020; 79:1344-1353. [PMID: 33249495 DOI: 10.1093/jnen/nlaa143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Blue light has been previously reported to play a salient role in the treatment of seasonal affective disorder. The present study aimed to investigate whether blue light had antidepressant effect on light-deprivation-induced depression model, and the underlying visual neural mechanism. Blue light mitigated depression-like behaviors induced by light deprivation as measured by elevated sucrose preference and reduced immobility time. Blue light enhanced melanopsin expression and light responses in the retina. We also found the upregulation of serotonin and brain derived neurotrophic factor expression in the c-fos-positive areas of rats treated with blue light compared with those maintained in darkness. The species gap between nocturnal albino (Sprague-Dawley rat) and diurnal pigmented animals (human) might have influenced extrapolating data to humans. Blue light has antidepressant effect on light-deprived Sprague-Dawley rats, which might be related to activating the serotonergic system and neurotrophic activity via the retinoraphe and retinoamygdala pathways. Blue light is the effective component of light therapy for treatment of depression.
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Affiliation(s)
- Qinghe Meng
- From the Department of Toxicology, School of Public Health, Peking University.,Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing, China
| | - Jianjun Jiang
- From the Department of Toxicology, School of Public Health, Peking University.,Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing, China
| | - Xiaohong Hou
- From the Department of Toxicology, School of Public Health, Peking University
| | - Lixia Jia
- From the Department of Toxicology, School of Public Health, Peking University.,Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing, China
| | - Xiaoxiao Duan
- From the Department of Toxicology, School of Public Health, Peking University
| | - Wenjuan Zhou
- From the Department of Toxicology, School of Public Health, Peking University
| | - Qi Zhang
- From the Department of Toxicology, School of Public Health, Peking University
| | - Zhiyuan Cheng
- From the Department of Toxicology, School of Public Health, Peking University
| | - Siqi Wang
- From the Department of Toxicology, School of Public Health, Peking University
| | - Qianqian Xiao
- From the Department of Toxicology, School of Public Health, Peking University
| | - Xuetao Wei
- From the Department of Toxicology, School of Public Health, Peking University.,Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing, China
| | - Weidong Hao
- From the Department of Toxicology, School of Public Health, Peking University.,Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing, China
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5
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Non-visual Opsins and Novel Photo-Detectors in the Vertebrate Inner Retina Mediate Light Responses Within the Blue Spectrum Region. Cell Mol Neurobiol 2020; 42:59-83. [PMID: 33231827 DOI: 10.1007/s10571-020-00997-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023]
Abstract
In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G protein- coupled receptors, likely involved in a number of non-image-forming processes, have been identified and characterized in cells of the inner retina of vertebrates. It is now known that the vertebrate retina is composed of visual photoreceptor cones and rods responsible for diurnal/color and nocturnal/black and white vision, and cells like the intrinsically photosensitive retinal ganglion cells (ipRGCs) and photosensitive horizontal cells in the inner retina, both detecting blue light and expressing the photopigment melanopsin (Opn4). Remarkably, these non-visual photopigments can continue to operate even in the absence of vision under retinal degeneration. Moreover, inner retinal neurons and Müller glial cells have been shown to express other photopigments such as the photoisomerase retinal G protein-coupled receptor (RGR), encephalopsin (Opn3), and neuropsin (Opn5), all able to detect blue/violet light and implicated in chromophore recycling, retinal clock synchronization, neuron-to-glia communication, and other activities. The discovery of these new photopigments in the inner retina of vertebrates is strong evidence of novel light-regulated activities. This review focuses on the features, localization, photocascade, and putative functions of these novel non-visual opsins in an attempt to shed light on their role in the inner retina of vertebrates and in the physiology of the whole organism.
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6
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Do MTH. Melanopsin and the Intrinsically Photosensitive Retinal Ganglion Cells: Biophysics to Behavior. Neuron 2019; 104:205-226. [PMID: 31647894 PMCID: PMC6944442 DOI: 10.1016/j.neuron.2019.07.016] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/19/2019] [Accepted: 07/12/2019] [Indexed: 12/19/2022]
Abstract
The mammalian visual system encodes information over a remarkable breadth of spatiotemporal scales and light intensities. This performance originates with its complement of photoreceptors: the classic rods and cones, as well as the intrinsically photosensitive retinal ganglion cells (ipRGCs). IpRGCs capture light with a G-protein-coupled receptor called melanopsin, depolarize like photoreceptors of invertebrates such as Drosophila, discharge electrical spikes, and innervate dozens of brain areas to influence physiology, behavior, perception, and mood. Several visual responses rely on melanopsin to be sustained and maximal. Some require ipRGCs to occur at all. IpRGCs fulfill their roles using mechanisms that include an unusual conformation of the melanopsin protein, an extraordinarily slow phototransduction cascade, divisions of labor even among cells of a morphological type, and unorthodox configurations of circuitry. The study of ipRGCs has yielded insight into general topics that include photoreceptor evolution, cellular diversity, and the steps from biophysical mechanisms to behavior.
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Affiliation(s)
- Michael Tri H Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Center for Life Science 12061, 3 Blackfan Circle, Boston, MA 02115, USA.
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7
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Benedetto MM, Guido ME, Contin MA. Non-Visual Photopigments Effects of Constant Light-Emitting Diode Light Exposure on the Inner Retina of Wistar Rats. Front Neurol 2017; 8:417. [PMID: 28871236 PMCID: PMC5566984 DOI: 10.3389/fneur.2017.00417] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022] Open
Abstract
The retina is part of the central nervous system specially adapted to capture light photons and transmit this information to the brain through photosensitive retinal cells involved in visual and non-visual activities. However, excessive light exposure may accelerate genetic retinal diseases or induce photoreceptor cell (PRC) death, finally leading to retinal degeneration (RD). Light pollution (LP) caused by the characteristic use of artificial light in modern day life may accelerate degenerative diseases or promote RD and circadian desynchrony. We have developed a working model to study RD mechanisms in a low light environment using light-emitting diode (LED) sources, at constant or long exposure times under LP conditions. The mechanism of PRC death is still not fully understood. Our main goal is to study the biochemical mechanisms of RD. We have previously demonstrated that constant light (LL) exposure to white LED produces a significant reduction in the outer nuclear layer (ONL) by classical PRC death after 7 days of LL exposure. The PRCs showed TUNEL-positive labeling and a caspase-3-independent mechanism of cell death. Here, we investigate whether constant LED exposure affects the inner-retinal organization and structure, cell survival and the expression of photopigments; in particular we look into whether constant LED exposure causes the death of retinal ganglion cells (RGCs), of intrinsically photosensitive RGCs (ipRGCs), or of other inner-retinal cells. Wistar rats exposed to 200 lx of LED for 2 to 8 days (LL 2 and LL 8) were processed for histological and protein. The results show no differences in the number of nucleus or TUNEL positive RGCs nor inner structural damage in any of LL groups studied, indicating that LL exposure affects ONL but does not produce RGC death. However, the photopigments melanopsin (OPN4) and neuropsin (OPN5) expressed in the inner retina were seen to modify their localization and expression during LL exposure. Our findings suggest that constant light during several days produces retinal remodeling and ONL cell death as well as significant changes in opsin expression in the inner nuclear layer.
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Affiliation(s)
- María M Benedetto
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mario E Guido
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María A Contin
- Facultad de Ciencias Químicas, Departamento de Química Biológica "Dr. Ranwel Caputto", Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
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8
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Bonmati-Carrion MA, Arguelles-Prieto R, Martinez-Madrid MJ, Reiter R, Hardeland R, Rol MA, Madrid JA. Protecting the melatonin rhythm through circadian healthy light exposure. Int J Mol Sci 2014; 15:23448-500. [PMID: 25526564 PMCID: PMC4284776 DOI: 10.3390/ijms151223448] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/02/2014] [Accepted: 11/09/2014] [Indexed: 12/14/2022] Open
Abstract
Currently, in developed countries, nights are excessively illuminated (light at night), whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD), including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs) and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.
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Affiliation(s)
| | | | | | - Russel Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
| | - Ruediger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen 37073, Germany.
| | - Maria Angeles Rol
- Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Juan Antonio Madrid
- Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
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9
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Georg B, Rask L, Hannibal J, Fahrenkrug J. The Light-InducedFOSResponse in Melanopsin Expressing HEK-293 Cells is Correlated with Melanopsin Quantity and Dependent on Light Duration and Irradiance. Photochem Photobiol 2014; 90:1069-76. [DOI: 10.1111/php.12298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/29/2014] [Indexed: 01/26/2023]
Affiliation(s)
- Birgitte Georg
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| | - Lene Rask
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
| | - Jan Fahrenkrug
- Department of Clinical Biochemistry; Faculty of Health Sciences; Bispebjerg Hospital; University of Copenhagen; Copenhagen NV Denmark
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10
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McMahon DG, Iuvone PM, Tosini G. Circadian organization of the mammalian retina: from gene regulation to physiology and diseases. Prog Retin Eye Res 2013; 39:58-76. [PMID: 24333669 DOI: 10.1016/j.preteyeres.2013.12.001] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/27/2013] [Accepted: 12/01/2013] [Indexed: 01/27/2023]
Abstract
The retinal circadian system represents a unique structure. It contains a complete circadian system and thus the retina represents an ideal model to study fundamental questions of how neural circadian systems are organized and what signaling pathways are used to maintain synchrony of the different structures in the system. In addition, several studies have shown that multiple sites within the retina are capable of generating circadian oscillations. The strength of circadian clock gene expression and the emphasis of rhythmic expression are divergent across vertebrate retinas, with photoreceptors as the primary locus of rhythm generation in amphibians, while in mammals clock activity is most robust in the inner nuclear layer. Melatonin and dopamine serve as signaling molecules to entrain circadian rhythms in the retina and also in other ocular structures. Recent studies have also suggested GABA as an important component of the system that regulates retinal circadian rhythms. These transmitter-driven influences on clock molecules apparently reinforce the autonomous transcription-translation cycling of clock genes. The molecular organization of the retinal clock is similar to what has been reported for the SCN although inter-neural communication among retinal neurons that form the circadian network is apparently weaker than those present in the SCN, and it is more sensitive to genetic disruption than the central brain clock. The melatonin-dopamine system is the signaling pathway that allows the retinal circadian clock to reconfigure retinal circuits to enhance light-adapted cone-mediated visual function during the day and dark-adapted rod-mediated visual signaling at night. Additionally, the retinal circadian clock also controls circadian rhythms in disk shedding and phagocytosis, and possibly intraocular pressure. Emerging experimental data also indicate that circadian clock is also implicated in the pathogenesis of eye disease and compelling experimental data indicate that dysfunction of the retinal circadian system negatively impacts the retina and possibly the cornea and the lens.
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Affiliation(s)
- Douglas G McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, 30310 GA, USA.
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11
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Ramsey DJ, Ramsey KM, Vavvas DG. Genetic advances in ophthalmology: the role of melanopsin-expressing, intrinsically photosensitive retinal ganglion cells in the circadian organization of the visual system. Semin Ophthalmol 2013; 28:406-21. [PMID: 24010846 DOI: 10.3109/08820538.2013.825294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Daily changes in the light-dark cycle are the principal environmental signal that enables organisms to synchronize their internal biology with the 24-hour day-night cycle. In humans, the visual system is integral to photoentrainment and is primarily driven by a specialized class of intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin (OPN4) in the inner retina. These cells project through the retinohypothalamic tract (RHT) to the suprachiasmatic nuclei (SCN) of the hypothalamus, which serves as the body's master biological clock. At the same time, the retina itself possesses intrinsic circadian oscillations, exemplified by diurnal fluctuations in visual sensitivity, neurotransmitter levels, and outer segment turnover rates. Recently, it has been noted that both central and peripheral oscillators share a molecular clock consisting of an endogenous, circadian-driven, transcription-translation feedback loop that cycles with a periodicity of approximately 24 hours. This review will cover the role that melanopsin and ipRGCs play in the circadian organization of the visual system.
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Affiliation(s)
- David J Ramsey
- Retina Service, Harvard Medical School, Massachusetts Eye and Ear Infirmary and Mass General Hospital , Boston, Massachusetts , USA
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12
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Hannibal J, Georg B, Fahrenkrug J. Differential expression of melanopsin mRNA and protein in Brown Norwegian rats. Exp Eye Res 2013. [DOI: 10.1016/j.exer.2012.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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13
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Roecklein KA, Wong PM, Miller MA, Donofry SD, Kamarck ML, Brainard GC. Melanopsin, photosensitive ganglion cells, and seasonal affective disorder. Neurosci Biobehav Rev 2012; 37:229-39. [PMID: 23286902 DOI: 10.1016/j.neubiorev.2012.12.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/05/2012] [Accepted: 12/21/2012] [Indexed: 02/05/2023]
Abstract
In two recent reports, melanopsin gene variations were associated with seasonal affective disorder (SAD), and in changes in the timing of sleep and activity in healthy individuals. New studies have deepened our understanding of the retinohypothalamic tract, which translates environmental light received by the retina into neural signals sent to a set of nonvisual nuclei in the brain that are responsible for functions other than sight including circadian, neuroendocrine and neurobehavioral regulation. Because this pathway mediates seasonal changes in physiology, behavior, and mood, individual variations in the pathway may explain why approximately 1-2% of the North American population develops mood disorders with a seasonal pattern (i.e., Major Depressive and Bipolar Disorders with a seasonal pattern, also known as seasonal affective disorder/SAD). Components of depression including mood changes, sleep patterns, appetite, and cognitive performance can be affected by the biological and behavioral responses to light. Specifically, variations in the gene sequence for the retinal photopigment, melanopsin, may be responsible for significant increased risk for mood disorders with a seasonal pattern, and may do so by leading to changes in activity and sleep timing in winter. The retinal sensitivity of SAD is hypothesized to be decreased compared to controls, and that further decrements in winter light levels may combine to trigger depression in winter. Here we outline steps for new research to address the possible role of melanopsin in seasonal affective disorder including chromatic pupillometry designed to measure the sensitivity of melanopsin containing retinal ganglion cells.
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Affiliation(s)
- Kathryn A Roecklein
- Department of Psychology, University of Pittsburgh, 3500 Sennott Square, 210 South Bouquet St., Pittsburgh, PA 15260, USA.
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14
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Roecklein KA, Wong PM, Franzen PL, Hasler BP, Wood-Vasey WM, Nimgaonkar VL, Miller MA, Kepreos KM, Ferrell RE, Manuck SB. Melanopsin gene variations interact with season to predict sleep onset and chronotype. Chronobiol Int 2012; 29:1036-47. [PMID: 22881342 DOI: 10.3109/07420528.2012.706766] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The human melanopsin gene has been reported to mediate risk for seasonal affective disorder (SAD), which is hypothesized to be caused by decreased photic input during winter when light levels fall below threshold, resulting in differences in circadian phase and/or sleep. However, it is unclear if melanopsin increases risk of SAD by causing differences in sleep or circadian phase, or if those differences are symptoms of the mood disorder. To determine if melanopsin sequence variations are associated with differences in sleep-wake behavior among those not suffering from a mood disorder, the authors tested associations between melanopsin gene polymorphisms and self-reported sleep timing (sleep onset and wake time) in a community sample (N = 234) of non-Hispanic Caucasian participants (age 30-54 yrs) with no history of psychological, neurological, or sleep disorders. The authors also tested the effect of melanopsin variations on differences in preferred sleep and activity timing (i.e., chronotype), which may reflect differences in circadian phase, sleep homeostasis, or both. Daylength on the day of assessment was measured and included in analyses. DNA samples were genotyped for melanopsin gene polymorphisms using fluorescence polarization. P10L genotype interacted with daylength to predict self-reported sleep onset (interaction p < .05). Specifically, sleep onset among those with the TT genotype was later in the day when individuals were assessed on longer days and earlier in the day on shorter days, whereas individuals in the other genotype groups (i.e., CC and CT) did not show this interaction effect. P10L genotype also interacted in an analogous way with daylength to predict self-reported morningness (interaction p < .05). These results suggest that the P10L TT genotype interacts with daylength to predispose individuals to vary in sleep onset and chronotype as a function of daylength, whereas other genotypes at P10L do not seem to have effects that vary by daylength. A better understanding of how melanopsin confers heightened responsivity to daylength may improve our understanding of a broad range of behavioral responses to light (i.e., circadian, sleep, mood) as well as the etiology of disorders with seasonal patterns of recurrence or exacerbation.
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Affiliation(s)
- Kathryn A Roecklein
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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15
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Glickman G, Webb IC, Elliott JA, Baltazar RM, Reale ME, Lehman MN, Gorman MR. Photic Sensitivity for Circadian Response to Light Varies with Photoperiod. J Biol Rhythms 2012; 27:308-18. [DOI: 10.1177/0748730412450826] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The response of the circadian system to light varies markedly depending on photic history. Under short day lengths, hamsters exhibit larger maximal light-induced phase shifts as compared with those under longer photoperiods. However, effects of photoperiod length on sensitivity to subsaturating light remain unknown. Here, Syrian hamsters were entrained to long or short photoperiods and subsequently exposed to a 15-min light pulse across a range of irradiances (0-68.03 µW/cm2) to phase shift activity rhythms. Phase advances exhibited a dose response, with increasing irradiances eliciting greater phase resetting in both conditions. Photic sensitivity, as measured by the half-saturation constant, was increased 40-fold in the short photoperiod condition. In addition, irradiances that generated similar phase advances under short and long days produced equivalent phase delays, and equal photon doses produced larger delays in the short photoperiod condition. Mechanistically, equivalent light exposure induced greater pERK, PER1, and cFOS immunoreactivity in the suprachiasmatic nuclei of animals under shorter days. Patterns of immunoreactivity in all 3 proteins were related to the size of the phase shift rather than the intensity of the photic stimulus, suggesting that photoperiod modulation of light sensitivity lies upstream of these events within the signal transduction cascade. This modulation of light sensitivity by photoperiod means that considerably less light is necessary to elicit a circadian response under the relatively shorter days of winter, extending upon the known seasonal changes in sensitivity of sensory systems. Further characterizing the mechanisms by which photoperiod alters photic response may provide a potent tool for optimizing light treatment for circadian and affective disorders in humans.
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Affiliation(s)
- Gena Glickman
- Center for Chronobiology and Department of Psychology, University of California, San Diego, CA
| | - Ian C. Webb
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Jeffrey A. Elliott
- Center for Chronobiology and Department of Psychology, University of California, San Diego, CA
| | - Ricardo M. Baltazar
- Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry University of Western Ontario, London, Ontario, Canada
| | - Meghan E. Reale
- Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry University of Western Ontario, London, Ontario, Canada
| | - Michael N. Lehman
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Michael R. Gorman
- Center for Chronobiology and Department of Psychology, University of California, San Diego, CA
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Differential expression of melanopsin isoforms Opn4L and Opn4S during postnatal development of the mouse retina. PLoS One 2012; 7:e34531. [PMID: 22496826 PMCID: PMC3320640 DOI: 10.1371/journal.pone.0034531] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 03/01/2012] [Indexed: 11/27/2022] Open
Abstract
Photosensitive retinal ganglion cells (pRGCs) respond to light from birth and represent the earliest known light detection system to develop in the mouse retina. A number of morphologically and functionally distinct subtypes of pRGCs have been described in the adult retina, and have been linked to different physiological roles. We have previously identified two distinct isoforms of mouse melanopsin, Opn4L and Opn4S, which are generated by alternate splicing of the Opn4 locus. These isoforms are differentially expressed in pRGC subtypes of the adult mouse retina, with both Opn4L and Opn4S detected in M1 type pRGCs, and only Opn4L detected in M2 type pRGCs. Here we investigate the developmental expression of Opn4L and Opn4S and show a differential profile of expression during postnatal development. Opn4S mRNA is detected at relatively constant levels throughout postnatal development, with levels of Opn4S protein showing a marked increase between P0 and P3, and then increasing progressively over time until adult levels are reached by P10. By contrast, levels of Opn4L mRNA and protein are low at birth and show a marked increase at P14 and P30 compared to earlier time points. We suggest that these differing profiles of expression are associated with the functional maturation of M1 and M2 subtypes of pRGCs. Based upon our data, Opn4S expressing M1 type pRGCs mature first and are the dominant pRGC subtype in the neonate retina, whereas increased expression of Opn4L and the maturation of M2 type pRGCs occurs later, between P10 and P14, at a similar time to the maturation of rod and cone photoreceptors. We suggest that the distinct functions associated with these cell types will develop at different times during postnatal development.
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17
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Zele AJ, Feigl B, Smith SS, Markwell EL. The circadian response of intrinsically photosensitive retinal ganglion cells. PLoS One 2011; 6:e17860. [PMID: 21423755 PMCID: PMC3056772 DOI: 10.1371/journal.pone.0017860] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 02/10/2011] [Indexed: 11/18/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGC) signal environmental
light level to the central circadian clock and contribute to the pupil light
reflex. It is unknown if ipRGC activity is subject to extrinsic (central) or
intrinsic (retinal) network-mediated circadian modulation during light
entrainment and phase shifting. Eleven younger persons (18–30 years) with
no ophthalmological, medical or sleep disorders participated. The activity of
the inner (ipRGC) and outer retina (cone photoreceptors) was assessed hourly
using the pupil light reflex during a 24 h period of constant environmental
illumination (10 lux). Exogenous circadian cues of activity, sleep, posture,
caffeine, ambient temperature, caloric intake and ambient illumination were
controlled. Dim-light melatonin onset (DLMO) was determined from salivary
melatonin assay at hourly intervals, and participant melatonin onset values were
set to 14 h to adjust clock time to circadian time. Here we demonstrate in
humans that the ipRGC controlled post-illumination pupil response has a
circadian rhythm independent of external light cues. This circadian variation
precedes melatonin onset and the minimum ipRGC driven pupil response occurs post
melatonin onset. Outer retinal photoreceptor contributions to the inner retinal
ipRGC driven post-illumination pupil response also show circadian variation
whereas direct outer retinal cone inputs to the pupil light reflex do not,
indicating that intrinsically photosensitive (melanopsin) retinal ganglion cells
mediate this circadian variation.
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Affiliation(s)
- Andrew J. Zele
- Institute of Health and Biomedical Innovation,
Queensland University of Technology, Brisbane, Australia
- School of Optometry, Queensland University of
Technology, Brisbane, Australia
- * E-mail: (AJZ); (BF)
| | - Beatrix Feigl
- Institute of Health and Biomedical Innovation,
Queensland University of Technology, Brisbane, Australia
- School of Optometry, Queensland University of
Technology, Brisbane, Australia
- * E-mail: (AJZ); (BF)
| | - Simon S. Smith
- Institute of Health and Biomedical Innovation,
Queensland University of Technology, Brisbane, Australia
- Centre for Accident Research and Road Safety
Queensland, Queensland University of Technology, Brisbane, Australia
| | - Emma L. Markwell
- Institute of Health and Biomedical Innovation,
Queensland University of Technology, Brisbane, Australia
- School of Optometry, Queensland University of
Technology, Brisbane, Australia
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18
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Abstract
Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors.
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Affiliation(s)
- Michael Tri Hoang Do
- Solomon H. Snyder Department of Neuroscience and Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
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19
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González-Menéndez I, Contreras F, Cernuda-Cernuda R, Provencio I, García-Fernández JM. Postnatal development and functional adaptations of the melanopsin photoreceptive system in the albino mouse retina. Invest Ophthalmol Vis Sci 2010; 51:4840-7. [PMID: 20435589 DOI: 10.1167/iovs.10-5253] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To study the melanopsin system of the albino CD1 mouse retina during postnatal development. METHODS Pups were kept under different ambient conditions: light/dark (LD) cycles, constant light (LL), constant darkness (DD), LL followed by LD, and DD followed by LL. Using immunohistochemistry, melanopsin-expressing cells were classified as M1 or M2 according to the location of their somata and dendritic processes and were counted. RESULTS Under LD cycles an increase in the number of immunoreactive cells was observed within the first week of postnatal development. When mice were maintained in DD, the increase in the number of immunopositive cells detected was significantly higher than that in LD. On the contrary, when mice were exposed to LL within the same period, no increase was detected. To determine whether the effect of LL during the early postnatal period was reversible, the authors studied animals born in LL and subsequently maintained under LD cycles. After 3 days in LD, these animals showed a significant increase in melanopsin cell number. However, after 1 month in LD, the number was similar to that of the LD controls. Surprisingly, when mice born in DD were exposed to LL, no decrease was detected, though the immunostaining was of low intensity. CONCLUSIONS The amount of melanopsin protein per cell varies, depending on ambient light conditions. Periods of darkness or, more likely, the sequence of light and dark periods occurring under the daily cycles might be necessary for the normal development of the melanopsin system.
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20
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Moldrup ML, Georg B, Falktoft B, Mortensen R, Hansen JL, Fahrenkrug J. Light inducesFosexpression via extracellular signal-regulated kinases 1/2 in melanopsin-expressing PC12 cells. J Neurochem 2010; 112:797-806. [DOI: 10.1111/j.1471-4159.2009.06504.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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21
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Abstract
The circadian clock is an evolutionarily, highly conserved feature of most organisms. This internal timing mechanism coordinates biochemical, physiological and behavioral processes to maintain synchrony with the environmental cycles of light, temperature and nutrients. Several studies have shown that light is the most potent cue used by most organisms (humans included) to synchronize daily activities. In mammals, light perception occurs only in the retina; three different types of photoreceptors are present within this tissue: cones, rods and the newly discovered intrinsically photosensitive retinal ganglion cells (ipRGCs). Researchers believe that the classical photoreceptors (e.g., the rods and the cones) are responsible for the image-forming vision, whereas the ipRGCs play a key role in the non-image forming vision. This non-image-forming photoreceptive system communicates not only with the master circadian pacemaker located in the suprachiasmatic nuclei of the hypothalamus, but also with many other brain areas that are known to be involved in the regulation of several functions; thus, this non-image forming system may also affect several aspects of mammalian health independently from the circadian system.
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Affiliation(s)
- Ketema N Paul
- Circadian Rhythms and Sleep Disorders Program, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
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22
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Ingham ES, Günhan E, Fuller PM, Fuller CA. Immunotoxin-induced ablation of melanopsin retinal ganglion cells in a non-murine mammalian model. J Comp Neurol 2009; 516:125-40. [PMID: 19575450 DOI: 10.1002/cne.22103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In mammals, non-image-forming visual functions, including circadian photoentrainment and the pupillary light reflex, are thought to be mediated by the combination of rods, cones, and the melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs). Although several genetic models have been developed to clarify the individual roles of the rod, cone, and ipRGC systems in mediating non-image visual function, assessing the in vivo role(s) of the ipRGCs has been complicated by the possibility of ontogenetic issues in these genetically modified animal models. In the present study, we describe the development and validation of an immunotoxin that specifically targets the ipRGC population in the mature mammalian retina. This ipRGC immunotoxin, consisting of saporin conjugated to a melanopsin polyclonal antibody, was evaluated with respect to its effectiveness and specificity in depleting the ipRGC population in the fully developed rat retina. The results showed that the ipRGC toxin rapidly and permanently depleted approximately 70% of the ipRGC population, without inducing appreciable changes in the cell number or morphology of any of the non-melanopsin-containing retinal cell populations investigated. These findings suggest that the newly developed ipRGC immunotoxin provides a potent method for achieving relatively rapid, permanent, and selective depletion of the ipRGC population in a non-murine model system. The development of this ipRGC-ablation method is the next step in elucidating the role of ipRGCs in mediating non-visual and circadian light-resetting responses in a wide range of non-murine mammalian models.
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Affiliation(s)
- Elizabeth S Ingham
- Department of Neurobiology, Physiology & Behavior, University of California, Davis, California 95616, USA
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23
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Smith MR, Eastman CI. Phase delaying the human circadian clock with blue-enriched polychromatic light. Chronobiol Int 2009; 26:709-25. [PMID: 19444751 DOI: 10.1080/07420520902927742] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The human circadian system is maximally sensitive to short-wavelength (blue) light. In a previous study we found no difference between the magnitude of phase advances produced by bright white versus bright blue-enriched light using light boxes in a practical protocol that could be used in the real world. Since the spectral sensitivity of the circadian system may vary with a circadian rhythm, we tested whether the results of our recent phase-advancing study hold true for phase delays. In a within-subjects counterbalanced design, this study tested whether bright blue-enriched polychromatic light (17000 K, 4000 lux) could produce larger phase delays than bright white light (4100 K, 5000 lux) of equal photon density (4.2x10(15) photons/cm(2)/sec). Healthy young subjects (n = 13) received a 2 h phase delaying light pulse before bedtime combined with a gradually delaying sleep/dark schedule on each of 4 consecutive treatment days. On the first treatment day the light pulse began 3 h after the dim light melatonin onset (DLMO). An 8 h sleep episode began at the end of the light pulse. Light treatment and the sleep schedule were delayed 2 h on each subsequent treatment day. A circadian phase assessment was conducted before and after the series of light treatment days to determine the time of the DLMO and DLMOff. Phase delays in the blue-enriched and white conditions were not significantly different (DLMO: -4.45+/-2.02 versus -4.48+/-1.97 h; DLMOff: -3.90+/-1.97 versus -4.35+/-2.39 h, respectively). These results indicate that at light levels commonly used for circadian phase shifting, blue-enriched polychromatic light is no more effective than the white polychromatic lamps of a lower correlated color temperature (CCT) for phase delaying the circadian clock.
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Affiliation(s)
- Mark R Smith
- Rush University Medical Center, Chicago, Illinois 60612, USA
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24
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González-Menéndez I, Contreras F, Cernuda-Cernuda R, García-Fernández JM. Daily rhythm of melanopsin-expressing cells in the mouse retina. Front Cell Neurosci 2009; 3:3. [PMID: 19562086 PMCID: PMC2701677 DOI: 10.3389/neuro.03.003.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 06/05/2009] [Indexed: 11/13/2022] Open
Abstract
In addition to some other functions, melanopsin-expressing retinal ganglion cells (RGCs) constitute the principal mediators of the circadian photoentrainment, a process by which the suprachiasmatic nucleus (the central clock of mammals), adjusts daily to the external day/night cycle. In the present study these RGCs were immunohistochemically labelled using a specific polyclonal antiserum raised against mouse melanopsin. A daily oscillation in the number of immunostained cells was detected in mice kept under a light / dark (LD) cycle. One hour before the lights were on (i.e., the end of the night period) the highest number of immunopositive cells was detected while the lowest was seen 4 h later (i.e., within the first hours of the light period). This finding suggests that some of the melanopsin-expressing RGCs “turn on” and “off” during the day/night cycle. We have also detected that these daily variations already occur in the early postnatal development, when the rod/cone photoreceptor system is not yet functional. Two main melanopsin-expressing cell subpopulations could be found within the retina: M1 cells showed robust dendritic arborization within the OFF sublamina of the inner plexiform layer (IPL), whilst M2 cells had fine dendritic processes within the ON sublamina of the IPL. These two cell subpopulations also showed different daily oscillations throughout the LD cycle. In order to find out whether or not the melanopsin rhythm was endogenous, other mice were maintained in constant darkness for 6 days. Under these conditions, no defined rhythm was detected, which suggests that the daily oscillation detected either is light-dependent or is gradually lost under constant conditions. This is the first study to analyze immunohistochemically the daily oscillation of the number of melanopsin-expressing cells in the mouse retina.
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