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Foster RG. Introduction and reflections on the comparative physiology of sleep and circadian rhythms. J Comp Physiol B 2024; 194:225-231. [PMID: 38856727 PMCID: PMC11233284 DOI: 10.1007/s00360-024-01567-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 05/17/2024] [Indexed: 06/11/2024]
Abstract
Circadian rhythms and the sleep/wake cycle allows us, and most life on Earth, to function optimally in a dynamic world, adjusting all aspects of biology to the varied and complex demands imposed by the 24-hour rotation of the Earth upon its axis. A key element in understanding these rhythms, and the success of the field in general, has been because researchers have adopted a comparative approach. Across all taxa, fundamental questions relating to the generation and regulation of sleep and circadian rhythms have been address using biochemical, molecular, cellular, system and computer modelling techniques. Furthermore, findings have been placed into an ecological and evolutionary context. By addressing both the "How" - mechanistic, and "Why" - evolutionary questions in parallel, the field has achieved remarkable successes, including how circadian rhythms are generated and regulated by light. Yet many key questions remain. In this special issue on the Comparative Physiology of Sleep and Circadian Rhythms, celebrating the 100th anniversary of the Journal of Comparative Physiology, important new discoveries are detailed. These findings illustrate the power of comparative physiology to address novel questions and demonstrate that sleep and circadian physiology are embedded within the biological framework of an organism.
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Affiliation(s)
- Russell G Foster
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Parks Road, Oxford, OX1 3QU, UK.
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Dai M, Liang PJ. GABA receptors mediate adaptation and sensitization processes in mouse retinal ganglion cells. Cogn Neurodyn 2024; 18:1021-1032. [PMID: 38826663 PMCID: PMC11143098 DOI: 10.1007/s11571-023-09950-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 02/07/2023] [Accepted: 03/09/2023] [Indexed: 06/04/2024] Open
Abstract
Two coordinated dynamic properties (adaptation and sensitization) are observed in retinal ganglion cells (RGCs) under the contrast stimulation. During sustained high-contrast period, adaptation decreases RGCs' responses while sensitization increases RGCs' responses. In mouse retina, adaptation and sensitization respectively show OFF- and ON-pathway-dominance. However, the mechanisms which drive the differentiation between adaptation and sensitization remain unclear. In the present study, multi-electrode recordings were conducted on isolated mouse retina under full-field contrast stimulation. Dynamic property was quantified based on the trend of RGC's firing rate during high-contrast period, light sensitivity was estimated by linear-nonlinear analysis and coding ability was estimated through stimulus reconstruction algorism. γ-Aminobutyric acid (GABA) receptors were pharmacologically blocked to explore the relation between RGCs' dynamic property and the activity of GABA receptors. It was found that GABAA and GABAC receptors respectively mediated the adaptation and sensitization processes in RGCs' responses. RGCs' dynamic property changes occurred after the blockage of GABA receptors were related to the modulation of the cells' light sensitivity. Further, the blockage of GABAA (GABAC) receptor significantly decreased RGCs' overall coding ability and eliminated the functional benefits of adaptation (sensitization). Our work suggests that the dynamic property of individual RGC is related to the balance between its GABAA-receptor-mediated inputs and GABAC-receptor-mediated inputs. Blockage of GABA receptors breaks the balance of retinal circuitry for signal processing, and down-regulates the visual information coding ability. Supplementary Information The online version contains supplementary material available at 10.1007/s11571-023-09950-2.
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Affiliation(s)
- Min Dai
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China
| | - Pei-Ji Liang
- School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240 China
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Pan D, Wang Z, Chen Y, Cao J. Melanopsin-mediated optical entrainment regulates circadian rhythms in vertebrates. Commun Biol 2023; 6:1054. [PMID: 37853054 PMCID: PMC10584931 DOI: 10.1038/s42003-023-05432-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023] Open
Abstract
Melanopsin (OPN4) is a light-sensitive protein that plays a vital role in the regulation of circadian rhythms and other nonvisual functions. Current research on OPN4 has focused on mammals; more evidence is needed from non-mammalian vertebrates to fully assess the significance of the non-visual photosensitization of OPN4 for circadian rhythm regulation. There are species differences in the regulatory mechanisms of OPN4 for vertebrate circadian rhythms, which may be due to the differences in the cutting variants, tissue localization, and photosensitive activation pathway of OPN4. We here summarize the distribution of OPN4 in mammals, birds, and teleost fish, and the classical excitation mode for the non-visual photosensitive function of OPN4 in mammals is discussed. In addition, the role of OPN4-expressing cells in regulating circadian rhythm in different vertebrates is highlighted, and the potential rhythmic regulatory effects of various neuropeptides or neurotransmitters expressed in mammalian OPN4-expressing ganglion cells are summarized among them.
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Affiliation(s)
- Deng Pan
- Laboratory of Anatomy of Domestic Animals, National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Haidian, 100193, Beijing, China
| | - Zixu Wang
- Laboratory of Anatomy of Domestic Animals, National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Haidian, 100193, Beijing, China
| | - Yaoxing Chen
- Laboratory of Anatomy of Domestic Animals, National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Haidian, 100193, Beijing, China
| | - Jing Cao
- Laboratory of Anatomy of Domestic Animals, National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Haidian, 100193, Beijing, China.
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Karthikeyan R, Davies WI, Gunhaga L. Non-image-forming functional roles of OPN3, OPN4 and OPN5 photopigments. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
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Raja S, Milosavljevic N, Allen AE, Cameron MA. Burning the candle at both ends: Intraretinal signaling of intrinsically photosensitive retinal ganglion cells. Front Cell Neurosci 2023; 16:1095787. [PMID: 36687522 PMCID: PMC9853061 DOI: 10.3389/fncel.2022.1095787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 12/13/2022] [Indexed: 01/09/2023] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are photoreceptors located in the ganglion cell layer. They project to brain regions involved in predominately non-image-forming functions including entrainment of circadian rhythms, control of the pupil light reflex, and modulation of mood and behavior. In addition to possessing intrinsic photosensitivity via the photopigment melanopsin, these cells receive inputs originating in rods and cones. While most research in the last two decades has focused on the downstream influence of ipRGC signaling, recent studies have shown that ipRGCs also act retrogradely within the retina itself as intraretinal signaling neurons. In this article, we review studies examining intraretinal and, in addition, intraocular signaling pathways of ipRGCs. Through these pathways, ipRGCs regulate inner and outer retinal circuitry through both chemical and electrical synapses, modulate the outputs of ganglion cells (both ipRGCs and non-ipRGCs), and influence arrangement of the correct retinal circuitry and vasculature during development. These data suggest that ipRGC function plays a significant role in the processing of image-forming vision at its earliest stage, positioning these photoreceptors to exert a vital role in perceptual vision. This research will have important implications for lighting design to optimize the best chromatic lighting environments for humans, both in adults and potentially even during fetal and postnatal development. Further studies into these unique ipRGC signaling pathways could also lead to a better understanding of the development of ocular dysfunctions such as myopia.
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Affiliation(s)
- Sushmitha Raja
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Nina Milosavljevic
- Division of Neuroscience, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Annette E. Allen
- Division of Neuroscience, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Morven A. Cameron
- School of Medicine, Western Sydney University, Sydney, NSW, Australia,*Correspondence: Morven A. Cameron,
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Abstract
Our physiology and behavior follow precise daily programs that adapt us to the alternating opportunities and challenges of day and night. Under experimental isolation, these rhythms persist with a period of approximately one day (circadian), demonstrating their control by an internal autonomous clock. Circadian time is created at the cellular level by a transcriptional/translational feedback loop (TTFL) in which the protein products of the Period and Cryptochrome genes inhibit their own transcription. Because the accumulation of protein is slow and delayed, the system oscillates spontaneously with a period of ∼24 hours. This cell-autonomous TTFL controls cycles of gene expression in all major tissues and these cycles underpin our daily metabolic programs. In turn, our innumerable cellular clocks are coordinated by a central pacemaker, the suprachiasmatic nucleus (SCN) of the hypothalamus. When isolated in slice culture, the SCN TTFL and its dependent cycles of neural activity persist indefinitely, operating as "a clock in a dish". In vivo, SCN time is synchronized to solar time by direct innervation from specialized retinal photoreceptors. In turn, the precise circadian cycle of action potential firing signals SCN-generated time to hypothalamic and brain stem targets, which co-ordinate downstream autonomic, endocrine, and behavioral (feeding) cues to synchronize and sustain the distributed cellular clock network. Circadian time therefore pervades every level of biological organization, from molecules to society. Understanding its mechanisms offers important opportunities to mitigate the consequences of circadian disruption, so prevalent in modern societies, that arise from shiftwork, aging, and neurodegenerative diseases, not least Huntington's disease.
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Affiliation(s)
- Andrew P. Patton
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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Tir S, Steel LCE, Tam SKE, Semo M, Pothecary CA, Vyazovskiy VV, Foster RG, Peirson SN. Rodent models in translational circadian photobiology. PROGRESS IN BRAIN RESEARCH 2022; 273:97-116. [PMID: 35940726 DOI: 10.1016/bs.pbr.2022.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Over the last decades remarkable advances have been made in the understanding of the photobiology of circadian rhythms. The identification of a third photoreceptive system in the mammalian eye, in addition to the rods and cones that mediate vision, has transformed our appreciation of the role of light in regulating physiology and behavior. These photosensitive retinal ganglion cells (pRGCs) express the blue-light sensitive photopigment melanopsin and project to the suprachiasmatic nuclei (SCN)-the master circadian pacemaker-as well as many other brain regions. Much of our understanding of the fundamental mechanisms of the pRGCs, and the processes that they regulate, comes from mouse and other rodent models. Here we describe the contribution of rodent models to circadian photobiology, including both their strengths and limitations. In addition, we discuss how an appreciation of both rodent and human data is important for translational circadian photobiology. Such an approach enables a bi-directional flow of information whereby an understanding of basic mechanisms derived from mice can be integrated with studies from humans. Progress in this field is being driven forward at several levels of analysis, not least by the use of personalized light measurements and photoreceptor specific stimuli in human studies, and by studying the impact of environmental, rather than laboratory, lighting on different rodent models.
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Affiliation(s)
- Selma Tir
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Laura C E Steel
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - S K E Tam
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Ma'ayan Semo
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Carina A Pothecary
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Vladyslav V Vyazovskiy
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Russell G Foster
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Stuart N Peirson
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute (SCNi), Kavli Institute for NanoScience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
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Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) signal not only anterogradely to drive behavioral responses, but also retrogradely to some amacrine interneurons to modulate retinal physiology. We previously found that all displaced amacrine cells with spiking, tonic excitatory photoresponses receive gap-junction input from ipRGCs, but the connectivity patterns and functional roles of ipRGC-amacrine coupling remained largely unknown. Here, we injected PoPro1 fluorescent tracer into all six types of mouse ipRGCs to identify coupled amacrine cells, and analyzed the latter's morphological and electrophysiological properties. We also examined how genetically disrupting ipRGC-amacrine coupling affected ipRGC photoresponses. Results showed that ipRGCs couple with not just ON- and ON/OFF-stratified amacrine cells in the ganglion-cell layer as previously reported, but also OFF-stratified amacrine cells in both ganglion-cell and inner nuclear layers. M1- and M3-type ipRGCs couple mainly with ON/OFF-stratified amacrine cells, whereas the other ipRGC types couple almost exclusively with ON-stratified ones. ipRGCs transmit melanopsin-based light responses to at least 93% of the coupled amacrine cells. Some of the ON-stratifying ipRGC-coupled amacrine cells exhibit transient hyperpolarizing light responses. We detected bidirectional electrical transmission between an ipRGC and a coupled amacrine cell, although transmission was asymmetric for this particular cell pair, favoring the ipRGC-to-amacrine direction. We also observed electrical transmission between two amacrine cells coupled to the same ipRGC. In both scenarios of coupling, the coupled cells often spiked synchronously. While ipRGC-amacrine coupling somewhat reduces the peak firing rates of ipRGCs' intrinsic melanopsin-based photoresponses, it renders these responses more sustained and longer-lasting. In summary, ipRGCs' gap junctional network involves more amacrine cell types and plays more roles than previously appreciated.
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Pant M, Zele AJ, Feigl B, Adhikari P. Light adaptation characteristics of melanopsin. Vision Res 2021; 188:126-138. [PMID: 34315092 DOI: 10.1016/j.visres.2021.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/14/2021] [Accepted: 07/07/2021] [Indexed: 11/20/2022]
Abstract
Following photopigment bleaching, the rhodopsin and cone-opsins show a characteristic exponential regeneration in the dark with a photocycle dependent on the retinal pigment epithelium. Melanopsin pigment regeneration in animal models requires different pathways to rods and cones. To quantify melanopsin-mediated light adaptation in humans, we first estimated its photopigment regeneration kinetics through the photo-bleach recovery of the intrinsic melanopsin pupil light response (PLR). An intense broadband light (~120,000 Td) bleached 43% of melanopsin compared to 86% of the cone-opsins. Recovery from a 43% bleach was 3.4X slower for the melanopsin than cone-opsin. Post-bleach melanopsin regeneration followed an exponential growth with a 2.5 min time-constant (τ) that required 11.2 min for complete recovery; the half-bleaching level (Ip) was ~ 4.47 log melanopic Td (16.10 log melanopsin effective photons.cm-2.s-1; 8.25 log photoisomerisations.photoreceptor-1.s-1). The effect on the cone-directed PLR of the level of the melanopsin excitation during continuous light adaptation was then determined. We observed that cone-directed pupil constriction amplitudes increased by ~ 10% when adapting lights had a higher melanopic excitation but the same mean photometric luminance. Our findings suggest that melanopsin light adaptation enhances cone signalling along the non-visual retina-brain axis. Parameters τ and Ip will allow estimation of the level of melanopsin bleaching in any light units; the data have implications for quantifying the relative contributions of putative melanopsin pathways to regulate the post-bleach photopigment regeneration and adaptation.
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Affiliation(s)
- Mukund Pant
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia
| | - Andrew J Zele
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia
| | - Beatrix Feigl
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; Queensland Eye Institute, Brisbane, Australia
| | - Prakash Adhikari
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia.
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The Dynamics of Public Perceptions and Climate Change in Swat Valley, Khyber Pakhtunkhwa, Pakistan. SUSTAINABILITY 2021. [DOI: 10.3390/su13084464] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
With rising temperatures, developing countries are exposed to the horrors of climate change more than ever. The poor infrastructure and low adaptation capabilities of these nations are the prime concern of current studies. Pakistan is vulnerable to climate-induced hazards including floods, droughts, water shortages, shifts in weather patterns, loss of biodiversity, melting of glaciers, and more in the coming years. For marginal societies dependent on natural resources, adaptation becomes a challenge and the utmost priority. Within the above context, this study was designed to fill the existing research gap concerning public knowledge of climate vulnerabilities and respective adaptation strategies in the northern Hindukush–Himalayan region of Pakistan. Using the stratified sampling technique, 25 union councils (wards) were selected from the nine tehsils (sub-districts) of the study area. Using the quantitative method approach, structured questionnaires were employed to collect data from 396 respondents. The study reveals varying public perceptions about different factors contributing to the causes and impacts of climate change and the sources of information in the three zones of the study area. The primary causes of climate change are deforestation, industrial waste, anthropogenic impurities, natural causes, and the burning of fossil fuels exacerbated by increased population. Changes in temperature, erratic rainfalls, floods, droughts, receding glaciers, and extreme weather events are some of the impacts observed over the past decades. While limiting the indiscriminate use of fossil fuels combined with government-assisted rehabilitation of forests can help combat climate change, the lack of proper education and economic, social, and governance barriers are hindering the local adaptation strategies. In addition, reduce environmental pollution (air, water, soil, etc.) and plantation polluted areas with suitable plants, are the two main actions in combating climate change. This study recommends policy interventions to enhance local adaptation efforts through building capacity, equipping local environmental institutions, discouraging deforestation, and ensuring sustainable use of natural resources.
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Tabuchi M, Coates KE, Bautista OB, Zukowski LH. Light/Clock Influences Membrane Potential Dynamics to Regulate Sleep States. Front Neurol 2021; 12:625369. [PMID: 33854471 PMCID: PMC8039321 DOI: 10.3389/fneur.2021.625369] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
The circadian rhythm is a fundamental process that regulates the sleep-wake cycle. This rhythm is regulated by core clock genes that oscillate to create a physiological rhythm of circadian neuronal activity. However, we do not know much about the mechanism by which circadian inputs influence neurons involved in sleep-wake architecture. One possible mechanism involves the photoreceptor cryptochrome (CRY). In Drosophila, CRY is receptive to blue light and resets the circadian rhythm. CRY also influences membrane potential dynamics that regulate neural activity of circadian clock neurons in Drosophila, including the temporal structure in sequences of spikes, by interacting with subunits of the voltage-dependent potassium channel. Moreover, several core clock molecules interact with voltage-dependent/independent channels, channel-binding protein, and subunits of the electrogenic ion pump. These components cooperatively regulate mechanisms that translate circadian photoreception and the timing of clock genes into changes in membrane excitability, such as neural firing activity and polarization sensitivity. In clock neurons expressing CRY, these mechanisms also influence synaptic plasticity. In this review, we propose that membrane potential dynamics created by circadian photoreception and core clock molecules are critical for generating the set point of synaptic plasticity that depend on neural coding. In this way, membrane potential dynamics drive formation of baseline sleep architecture, light-driven arousal, and memory processing. We also discuss the machinery that coordinates membrane excitability in circadian networks found in Drosophila, and we compare this machinery to that found in mammalian systems. Based on this body of work, we propose future studies that can better delineate how neural codes impact molecular/cellular signaling and contribute to sleep, memory processing, and neurological disorders.
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Affiliation(s)
- Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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Harrison KR, Chervenak AP, Resnick SM, Reifler AN, Wong KY. Amacrine Cells Forming Gap Junctions With Intrinsically Photosensitive Retinal Ganglion Cells: ipRGC Types, Neuromodulator Contents, and Connexin Isoform. Invest Ophthalmol Vis Sci 2021; 62:10. [PMID: 33410914 PMCID: PMC7804497 DOI: 10.1167/iovs.62.1.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
Purpose Intrinsically photosensitive retinal ganglion cells (ipRGCs) signal not only centrally to non-image-forming visual centers of the brain but also intraretinally to amacrine interneurons through gap junction electrical coupling, potentially modulating image-forming retinal processing. We aimed to determine (1) which ipRGC types couple with amacrine cells, (2) the neuromodulator contents of ipRGC-coupled amacrine cells, and (3) whether connexin36 (Cx36) contributes to ipRGC-amacrine coupling. Methods Gap junction-permeable Neurobiotin tracer was injected into green fluorescent protein (GFP)-labeled ipRGCs in Opn4Cre/+; Z/EG mice to stain coupled amacrine cells, and immunohistochemistry was performed to reveal the neuromodulator contents of the Neurobiotin-stained amacrine cells. We also created Opn4Cre/+; Cx36flox/flox; Z/EG mice to knock out Cx36 in GFP-labeled ipRGCs and looked for changes in the number of ipRGC-coupled amacrine cells. Results Seventy-three percent of ipRGCs, including all six types (M1-M6), were tracer-coupled with amacrine somas 5.7 to 16.5 µm in diameter but not with ganglion cells. Ninety-two percent of the ipRGC-coupled somas were in the ganglion cell layer and the rest in the inner nuclear layer. Some ipRGC-coupled amacrine cells were found to accumulate serotonin or to contain nitric oxide synthase or neuropeptide Y. Knocking out Cx36 in M2 and M4 dramatically reduced the number of coupled somas. Conclusions Heterologous gap junction coupling with amacrine cells is widespread across mouse ipRGC types. ipRGC-coupled amacrine cells probably comprise multiple morphologic types and use multiple neuromodulators, suggesting that gap junctional ipRGC-to-amacrine signaling likely exerts diverse modulatory effects on retinal physiology. ipRGC-amacrine coupling is mediated partly, but not solely, by Cx36.
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Affiliation(s)
- Krystal R. Harrison
- Department of Molecular, Cellular, & Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
| | - Andrew P. Chervenak
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Sarah M. Resnick
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Aaron N. Reifler
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Kwoon Y. Wong
- Department of Molecular, Cellular, & Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
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de Melo Reis RA, Freitas HR, de Mello FG. Cell Calcium Imaging as a Reliable Method to Study Neuron-Glial Circuits. Front Neurosci 2020; 14:569361. [PMID: 33122991 PMCID: PMC7566175 DOI: 10.3389/fnins.2020.569361] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/24/2020] [Indexed: 12/12/2022] Open
Abstract
Complex dynamic cellular networks have been studied in physiological and pathological processes under the light of single-cell calcium imaging (SCCI), a method that correlates functional data based on calcium shifts operated by different intracellular and extracellular mechanisms integrated with their cell phenotypes. From the classic synaptic structure to tripartite astrocytic model or the recent quadripartite microglia added ensemble, as well as other physiological tissues, it is possible to follow how cells signal spatiotemporally to cellular patterns. This methodology has been used broadly due to the universal properties of calcium as a second messenger. In general, at least two types of receptor operate through calcium permeation: a fast-acting ionotropic receptor channel and a slow-activating metabotropic receptor, added to exchangers/transporters/pumps and intracellular Ca2+ release activated by messengers. These prototypes have gained an enormous amount of information in dynamic signaling circuits. SCCI has also been used as a method to associate phenotypic markers during development and stage transitions in progenitors, stem, vascular cells, neuro- and glioblasts, neurons, astrocytes, oligodendrocytes, and microglia that operate through ion channels, transporters, and receptors. Also, cancer cells or inducible cell lines from human organoids characterized by transition stages are currently being used to model diseases or reconfigure healthy cells in terms of the expression of calcium-binding/permeable molecules and shed light on therapy.
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Affiliation(s)
- Ricardo Augusto de Melo Reis
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hércules Rezende Freitas
- Department of Pathology and Laboratory Medicine, MIND Institute, University of California, Davis, Sacramento, CA, United States
| | - Fernando Garcia de Mello
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Todd WD. Potential Pathways for Circadian Dysfunction and Sundowning-Related Behavioral Aggression in Alzheimer's Disease and Related Dementias. Front Neurosci 2020; 14:910. [PMID: 33013301 PMCID: PMC7494756 DOI: 10.3389/fnins.2020.00910] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/06/2020] [Indexed: 12/19/2022] Open
Abstract
Patients with Alzheimer's disease (AD) and related dementias are commonly reported to exhibit aggressive behavior and other emotional behavioral disturbances, which create a tremendous caretaker burden. There has been an abundance of work highlighting the importance of circadian function on mood and emotional behavioral regulation, and recent evidence demonstrates that a specific hypothalamic pathway links the circadian system to neurons that modulate aggressive behavior, regulating the propensity for aggression across the day. Such shared circuitry may have important ramifications for clarifying the complex interactions underlying "sundowning syndrome," a poorly understood (and even controversial) clinical phenomenon in AD and dementia patients that is characterized by agitation, aggression, and delirium during the late afternoon and early evening hours. The goal of this review is to highlight the potential output and input pathways of the circadian system that may underlie circadian dysfunction and behavioral aggression associated with sundowning syndrome, and to discuss possible ways these pathways might inform specific interventions for treatment. Moreover, the apparent bidirectional relationship between chronic disruptions of circadian and sleep-wake regulation and the pathology and symptoms of AD suggest that understanding the role of these circuits in such neurobehavioral pathologies could lead to better diagnostic or even preventive measures.
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Affiliation(s)
- William D Todd
- Program in Neuroscience, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, United States
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Foster RG, Hughes S, Peirson SN. Circadian Photoentrainment in Mice and Humans. BIOLOGY 2020; 9:biology9070180. [PMID: 32708259 PMCID: PMC7408241 DOI: 10.3390/biology9070180] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 12/26/2022]
Abstract
Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.
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Abstract
At the core of human thought, for the majority of individuals in the developed nations at least, there is the tacit assumption that as a species we are unfettered by the demands imposed by our biology and that we can do what we want, at whatever time we choose, whereas in reality every aspect of our physiology and behaviour is constrained by a 24 h beat arising from deep within our evolution. Our daily circadian rhythms and sleep/wake cycle allow us to function optimally in a dynamic world, adjusting our biology to the demands imposed by the day/night cycle. The themes developed in this review focus upon the growing realization that we ignore the circadian and sleep systems at our peril, and this paper considers the mechanisms that generate and regulate circadian and sleep systems; what happens mechanistically when these systems collapse as a result of societal pressures and disease; how sleep disruption and stress are linked; why sleep disruption and mental illness invariably occur together; and how individuals and employers can attempt to mitigate some of the problems associated with working against our internal temporal biology. While some of the health costs of sleep disruption can be reduced, in the short-term at least, there will always be significant negative consequences associated with shift work and sleep loss. With this in mind, society needs to address this issue and decide when the consequences of sleep disruption are justified in the workplace.
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Affiliation(s)
- Russell G. Foster
- Sleep and Circadian Neuroscience Institute (SCNi) and Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, OMPI, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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17
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The Role of Purinergic Receptors in the Circadian System. Int J Mol Sci 2020; 21:ijms21103423. [PMID: 32408622 PMCID: PMC7279285 DOI: 10.3390/ijms21103423] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 12/24/2022] Open
Abstract
The circadian system is an internal time-keeping system that synchronizes the behavior and physiology of an organism to the 24 h solar day. The master circadian clock, the suprachiasmatic nucleus (SCN), resides in the hypothalamus. It receives information about the environmental light/dark conditions through the eyes and orchestrates peripheral oscillators. Purinergic signaling is mediated by extracellular purines and pyrimidines that bind to purinergic receptors and regulate multiple body functions. In this review, we highlight the interaction between the circadian system and purinergic signaling to provide a better understanding of rhythmic body functions under physiological and pathological conditions.
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Eleftheriou CG, Wright P, Allen AE, Elijah D, Martial FP, Lucas RJ. Melanopsin Driven Light Responses Across a Large Fraction of Retinal Ganglion Cells in a Dystrophic Retina. Front Neurosci 2020; 14:320. [PMID: 32317928 PMCID: PMC7147324 DOI: 10.3389/fnins.2020.00320] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/18/2020] [Indexed: 02/02/2023] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and project to central targets, allowing them to contribute to both image-forming and non-image forming vision. Recent studies have highlighted chemical and electrical synapses between ipRGCs and neurons of the inner retina, suggesting a potential influence from the melanopsin-born signal to affect visual processing at an early stage of the visual pathway. We investigated melanopsin responses in ganglion cell layer (GCL) neurons of both intact and dystrophic mouse retinas using 256 channel multi-electrode array (MEA) recordings. A wide 200 μm inter-electrode spacing enabled a pan-retinal visualization of melanopsin's influence upon GCL activity. Upon initial stimulation of dystrophic retinas with a long, bright light pulse, over 37% of units responded with an increase in firing (a far greater fraction than can be expected from the anatomically characterized number of ipRGCs). This relatively widespread response dissipated with repeated stimulation even at a quite long inter-stimulus interval (ISI; 120 s), to leave a smaller fraction of responsive units (<10%; more in tune with the predicted number of ipRGCs). Visually intact retinas appeared to lack such widespread melanopsin responses indicating that it is a feature of dystrophy. Taken together, our data reveal the potential for anomalously widespread melanopsin responses in advanced retinal degeneration. These could be used to probe the functional reorganization of retinal circuits in degeneration and should be taken into account when using retinally degenerate mice as a model of disease.
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Affiliation(s)
- Cyril G. Eleftheriou
- Burke Neurological Institute at Weill Cornell Medicine, White Plains, NY, United States
| | - Phillip Wright
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Annette E. Allen
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Daniel Elijah
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Franck P. Martial
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Robert J. Lucas
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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19
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Lewis P, Oster H, Korf HW, Foster RG, Erren TC. Food as a circadian time cue - evidence from human studies. Nat Rev Endocrinol 2020; 16:213-223. [PMID: 32055029 DOI: 10.1038/s41574-020-0318-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/06/2020] [Indexed: 12/28/2022]
Abstract
Meal timing and composition are frequently reported in the literature as zeitgebers (that is, time cues) for the circadian system of humans and animal models, albeit secondary to light. Although widely assumed to be true, evidence for food zeitgeber effects specific to humans is notably scarce. Fostering zeitgeber hygiene in the general population as the development and practice of healthy use of zeitgebers could potentially reduce chronobiological strain, which is defined as disruption or misalignment within the circadian system. Such chronobiological strain is associated with modern 24/7 lifestyles (for example, shift work) and several negative health outcomes. Adjustments to meal timing and composition are an attractive strategy to synchronize circadian rhythms and develop zeitgeber hygiene. Thus, clarifying the actual effect of meal timing and composition on the human circadian system is a crucial piece of the human chronobiology puzzle. This Review weighs the evidence from human studies pertaining to the hypothesis that food is a circadian zeitgeber by comparing findings against formal zeitgeber criteria put forward by Jürgen Aschoff in the 1950s.
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Affiliation(s)
- Philip Lewis
- Institute and Policlinic for Occupational Medicine, Environmental Medicine and Prevention Research, University Hospital of Cologne, University of Cologne, Cologne, Germany.
| | - Henrik Oster
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany
| | - Horst W Korf
- Institute of Anatomy I, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Thomas C Erren
- Institute and Policlinic for Occupational Medicine, Environmental Medicine and Prevention Research, University Hospital of Cologne, University of Cologne, Cologne, Germany
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20
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Kwon J, Ko S, Lee J, Na J, Sung J, Lee HJ, Lee S, Chung S, Choi HJ. Nanoelectrode-mediated single neuron activation. NANOSCALE 2020; 12:4709-4718. [PMID: 32049079 DOI: 10.1039/c9nr10559j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Elucidating cellular dynamics at the level of a single neuron and its associated role within neuronal circuits is essential for interpreting the complex nature of the brain. To investigate the operation of neural activity within its network, it is necessary to precisely manipulate the activation of each neuron and verify its propagation path via the synaptic connection. In this study, by exploiting the intrinsic physical and electrical advantages of a nanoelectrode, a vertical nanowire multi electrode array (VNMEA) is developed as a neuronal activation platform presenting the spatially confined effect on the intracellular space of individual cells. VNMEA makes a distinct difference between the interior and exterior cell potential and the current density, deriving the superior effects on activating Ca2+ responses compared to extracellular methods under the same conditions, with about 2.9-fold higher amplitude of Ca2+ elevation and a 2.6-fold faster recovery rate. Moreover, the synchronized propagation of evoked activities is shown in connected neurons implying cell-to-cell communications following the intracellular stimulation. The simulation and experimental consequences prove the outstanding property of temporal/spatial confinement of VNMEA-mediated intracellular stimulation to activate a single neuron and show its potential in localizing spiking neurons within neuronal populations, which may be utilized to reveal the connection and activation modalities of neural networks.
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Affiliation(s)
- Juyoung Kwon
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Sukjin Ko
- Brain Korea 21 Plus Project for Medical Science, Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
| | - Jaejun Lee
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Jukwan Na
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Jaesuk Sung
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Hyo-Jung Lee
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Seonghyeon Lee
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Seungsoo Chung
- Brain Korea 21 Plus Project for Medical Science, Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
| | - Heon-Jin Choi
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
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21
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Sondereker KB, Stabio ME, Renna JM. Crosstalk: The diversity of melanopsin ganglion cell types has begun to challenge the canonical divide between image-forming and non-image-forming vision. J Comp Neurol 2020; 528:2044-2067. [PMID: 32003463 DOI: 10.1002/cne.24873] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 12/15/2022]
Abstract
Melanopsin ganglion cells have defied convention since their discovery almost 20 years ago. In the years following, many types of these intrinsically photosensitive retinal ganglion cells (ipRGCs) have emerged. In the mouse retina, there are currently six known types (M1-M6) of melanopsin ganglion cells, each with unique morphology, mosaics, connections, physiology, projections, and functions. While melanopsin-expressing cells are usually associated with behaviors like circadian photoentrainment and the pupillary light reflex, the characterization of multiple types has demonstrated a reach that may extend far beyond non-image-forming vision. In fact, studies have shown that individual types of melanopsin ganglion cells have the potential to impact image-forming functions like contrast sensitivity and color opponency. Thus, the goal of this review is to summarize the morphological and functional aspects of the six known types of melanopsin ganglion cells in the mouse retina and to highlight their respective roles in non-image-forming and image-forming vision. Although many melanopsin ganglion cell types do project to image-forming brain targets, it is important to note that this is only the first step in determining their influence on image-forming vision. Even so, the visual system has canonically been divided into these two functional realms and melanopsin ganglion cells have begun to challenge the boundary between them, providing an overlap of visual information that is complementary rather than redundant. Further studies on these ganglion cell photoreceptors will no doubt continue to illustrate an ever-expanding role for melanopsin ganglion cells in image-forming vision.
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Affiliation(s)
| | - Maureen E Stabio
- Department of Cell & Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
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22
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Kusumoto J, Takeo M, Hashikawa K, Komori T, Tsuji T, Terashi H, Sakakibara S. OPN4 belongs to the photosensitive system of the human skin. Genes Cells 2020; 25:215-225. [DOI: 10.1111/gtc.12751] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/18/2020] [Accepted: 01/21/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Junya Kusumoto
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
- Department of Oral and Maxillofacial Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Makoto Takeo
- Laboratory for Organ Regeneration RIKEN Center for Biosystems Dynamics Research Kobe Japan
| | - Kazunobu Hashikawa
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Takahide Komori
- Department of Oral and Maxillofacial Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Takashi Tsuji
- Laboratory for Organ Regeneration RIKEN Center for Biosystems Dynamics Research Kobe Japan
| | - Hiroto Terashi
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
| | - Shunsuke Sakakibara
- Department of Plastic Surgery Kobe University Graduate School of Medicine Kobe Japan
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23
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Gong X, Wu XH, Liu AL, Qian KW, Li YY, Ma YY, Huang F, Wang Q, Wu H, Zhou X, Qu J, Yuan F, Zhong YM, Yang XL, Weng SJ. Optic nerve crush modulates refractive development of the C57BL/6 mouse by changing multiple ocular dimensions. Brain Res 2019; 1726:146537. [PMID: 31672473 DOI: 10.1016/j.brainres.2019.146537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/17/2019] [Accepted: 10/26/2019] [Indexed: 01/16/2023]
Abstract
Higher visual centers could modulate visually-guided ocular growth, in addition to local mechanisms intrinsic to the eye. There is evidence that such central modulations could be species (even subspecies)-dependent. While the mouse has recently become an important experimental animal in myopia studies, it remains unclear whether and how visual centers modulate refractive development in mice, an issue that was examined in the present study. We found that optic nerve crush (ONC), performed at P18, could modify normal refractive development in the C57BL/6 mouse raised in normal visual environment. Unexpectedly, sham surgery caused a steeper cornea, leading to a modest myopic refractive shift, but did not induce significant changes in ocular axis length. ONC caused corneal flattening and re-calibrated the refractive set-point in a bidirectional manner, causing significant myopic (<-3 D, 54.5%) or hyperopic (>+3 D, 18.2%) shifts in refractive error in most (totally 72.7%) animals, both due to changes in ocular axial length. ONC did not change the density of dopaminergic amacrine cells, but increased retinal levels of dopamine and DOPAC. We conclude that higher visual centers are likely to play a role in fine-tuning of ocular growth, thus modifying refractive development in the C57BL/6 mouse. The changes in refractive error induced by ONC are accounted for by alternations in multiple ocular dimensions, including corneal curvature and axial length.
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Affiliation(s)
- Xue Gong
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiao-Hua Wu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China; Discipline of Neuroscience and Department of Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ai-Lin Liu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Kang-Wei Qian
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yun-Yun Li
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuan-Yuan Ma
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Furong Huang
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qiongsi Wang
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Hao Wu
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiangtian Zhou
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jia Qu
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Fei Yuan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yong-Mei Zhong
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiong-Li Yang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Shi-Jun Weng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurology and Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China.
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24
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Felder-Schmittbuhl MP, Buhr ED, Dkhissi-Benyahya O, Hicks D, Peirson SN, Ribelayga CP, Sandu C, Spessert R, Tosini G. Ocular Clocks: Adapting Mechanisms for Eye Functions and Health. Invest Ophthalmol Vis Sci 2019; 59:4856-4870. [PMID: 30347082 PMCID: PMC6181243 DOI: 10.1167/iovs.18-24957] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Vision is a highly rhythmic function adapted to the extensive changes in light intensity occurring over the 24-hour day. This adaptation relies on rhythms in cellular and molecular processes, which are orchestrated by a network of circadian clocks located within the retina and in the eye, synchronized to the day/night cycle and which, together, fine-tune detection and processing of light information over the 24-hour period and ensure retinal homeostasis. Systematic or high throughput studies revealed a series of genes rhythmically expressed in the retina, pointing at specific functions or pathways under circadian control. Conversely, knockout studies demonstrated that the circadian clock regulates retinal processing of light information. In addition, recent data revealed that it also plays a role in development as well as in aging of the retina. Regarding synchronization by the light/dark cycle, the retina displays the unique property of bringing together light sensitivity, clock machinery, and a wide range of rhythmic outputs. Melatonin and dopamine play a particular role in this system, being both outputs and inputs for clocks. The retinal cellular complexity suggests that mechanisms of regulation by light are diverse and intricate. In the context of the whole eye, the retina looks like a major determinant of phase resetting for other tissues such as the retinal pigmented epithelium or cornea. Understanding the pathways linking the cell-specific molecular machineries to their cognate outputs will be one of the major challenges for the future.
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Affiliation(s)
- Marie-Paule Felder-Schmittbuhl
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Ethan D Buhr
- Department of Ophthalmology, University of Washington Medical School, Seattle, Washington, United States
| | - Ouria Dkhissi-Benyahya
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - David Hicks
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Christophe P Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States
| | - Cristina Sandu
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
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25
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Hastings MH, Maywood ES, Brancaccio M. The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker. BIOLOGY 2019; 8:E13. [PMID: 30862123 PMCID: PMC6466121 DOI: 10.3390/biology8010013] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 11/16/2022]
Abstract
The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants (Arabidopsis), insects (Drosophila) and mammals (mouse and humans), a common mechanistic motif of delayed negative feedback has emerged as the Deus ex machina for the cellular definition of ca. 24 h cycles. This review will consider, briefly, comparative circadian clock biology and will then focus on the mammalian circadian system, considering its molecular genetic basis, the properties of the suprachiasmatic nucleus (SCN) as the principal circadian clock in mammals and its role in synchronising a distributed peripheral circadian clock network. Finally, it will consider new directions in analysing the cell-autonomous and circuit-level SCN clockwork and will highlight the surprising discovery of a central role for SCN astrocytes as well as SCN neurons in controlling circadian behaviour.
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Affiliation(s)
- Michael H Hastings
- MRC Laboratory of Molecular Biology, Division of Neurobiology, CB2 0QH Cambridge, UK.
| | - Elizabeth S Maywood
- MRC Laboratory of Molecular Biology, Division of Neurobiology, CB2 0QH Cambridge, UK.
| | - Marco Brancaccio
- UK Dementia Research Institute at Imperial College London, Division of Brain Sciences, Department of Medicine, W12 0NN London, UK.
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26
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Palumaa T, Gilhooley MJ, Jagannath A, Hankins MW, Hughes S, Peirson SN. Melanopsin: photoreceptors, physiology and potential. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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27
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Katz B, Minke B. The Drosophila light-activated TRP and TRPL channels - Targets of the phosphoinositide signaling cascade. Prog Retin Eye Res 2018; 66:200-219. [DOI: 10.1016/j.preteyeres.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/29/2018] [Accepted: 05/02/2018] [Indexed: 01/28/2023]
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28
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Hayter EA, Brown TM. Additive contributions of melanopsin and both cone types provide broadband sensitivity to mouse pupil control. BMC Biol 2018; 16:83. [PMID: 30064443 PMCID: PMC6066930 DOI: 10.1186/s12915-018-0552-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/20/2018] [Indexed: 01/13/2023] Open
Abstract
Background Intrinsically photosensitive retinal ganglion cells (ipRGCs) drive an array of non-image-forming (NIF) visual responses including circadian photoentrainment and the pupil light reflex. ipRGCs integrate extrinsic (rod/cone) and intrinsic (melanopsin) photoreceptive signals, but the contribution of cones to ipRGC-dependent responses remains incompletely understood. Given recent data revealing that cone-derived colour signals influence mouse circadian timing and pupil responses in humans, here we set out to investigate the role of colour information in pupil control in mice. Results We first recorded electrophysiological activity from the pretectal olivary nucleus (PON) of anaesthetised mice with a red-shifted cone population (Opn1mwR) and mice lacking functional cones (Cnga3−/−) or melanopsin (Opn1mwR; Opn4−/−). Using multispectral stimuli to selectively modulate the activity of individual opsin classes, we show that PON cells which receive ipRGC input also exhibit robust S- and/or L-cone opsin-driven activity. This population includes many cells where the two cone opsins drive opponent responses (most commonly excitatory/ON responses to S-opsin stimulation and inhibitory/OFF responses to L-opsin stimulation). These cone inputs reliably tracked even slow (0.025 Hz) changes in illuminance/colour under photopic conditions with melanopsin contributions becoming increasingly dominant for higher-contrast/lower temporal frequency stimuli. We also evaluated consensual pupil responses in awake animals and show that, surprisingly, this aspect of physiology is insensitive to chromatic signals originating with cones. Instead, by contrast with the situation in humans, signals from melanopsin and both cone opsins combine in a purely additive manner to drive pupil constriction in mice. Conclusion Our data reveal a key difference in the sensory control of the mouse pupil relative to another major target of ipRGCs—the circadian clock. Whereas the latter uses colour information to help estimate time of day, the mouse pupil instead sums signals across cone opsin classes to provide broadband spectral sensitivity to changes in illumination. As such, while the widespread co-occurrence of chromatic responses and melanopsin input in the PON supports a close association between colour discrimination mechanisms and NIF visual processing, our data suggest that colour opponent PON cells in the mouse contribute to functions other than pupil control. Electronic supplementary material The online version of this article (10.1186/s12915-018-0552-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Edward A Hayter
- Faculty of Biology, Medicine and Health, University of Manchester, AV Hill Building, Oxford Road, Manchester, M13 9PT, UK
| | - Timothy M Brown
- Faculty of Biology, Medicine and Health, University of Manchester, AV Hill Building, Oxford Road, Manchester, M13 9PT, UK.
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Saito M, Miyamoto K, Uchiyama Y, Murakami I. Invisible light inside the natural blind spot alters brightness at a remote location. Sci Rep 2018; 8:7540. [PMID: 29765135 PMCID: PMC5954096 DOI: 10.1038/s41598-018-25920-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/05/2018] [Indexed: 12/13/2022] Open
Abstract
The natural blind spot in the visual field has been known as a large oval region that cannot receive any optical input because it corresponds to the retinal optic disk containing no rod/cone-photoreceptors. Recently, stimulation inside the blind spot was found to enhance, but not trigger, the pupillary light reflex. However, it is unknown whether blind-spot stimulation also affects visual perception. We addressed this question using psychophysical brightness-matching experiments. We found that a test stimulus outside the blind spot was judged as darker when it was accompanied by a consciously unexperienced blue oval inside the blind spot; moreover, the pupillary light reflex was enhanced. These findings suggested that a photo-sensitive mechanism inside the optic disk, presumably involving the photopigment melanopsin, contributes to our image-forming vision and provides a ‘reference’ for calibrating the perceived brightness of visual objects.
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Affiliation(s)
- Marina Saito
- Department of Psychology, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Kentaro Miyamoto
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, 113-0033, Japan.,Department of Experimental Psychology, University of Oxford, Oxford, OX1 3UD, United Kingdom.,Japan Society for the Promotion of Science, Tokyo, 102-8472, Japan
| | - Yusuke Uchiyama
- Department of Psychology, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Ikuya Murakami
- Department of Psychology, The University of Tokyo, Tokyo, 113-0033, Japan.
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30
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Zele AJ, Adhikari P, Feigl B, Cao D. Cone and melanopsin contributions to human brightness estimation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B19-B25. [PMID: 29603934 DOI: 10.1364/josaa.35.000b19] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/17/2017] [Indexed: 06/08/2023]
Abstract
We determined the contributions of cone and melanopsin luminance signaling to human brightness perception. The absolute brightness of four narrowband primary lights presented in a full-field Ganzfeld was estimated in two conditions, either cone luminance-equated (186.7-1,867.0 cd·m-2) or melanopsin luminance-equated (31.6-316.3 melanopsin cd·m-2). We show that brightness estimations for each primary light follow an approximately linear increase with increasing cone or melanopsin luminance (in log units), but are not equivalent for primary lights equated with either cone or melanopsin luminance. Instead, brightness estimations result from a combined interaction between cone and melanopsin signaling. Analytical modeling with wavelength-dependent coefficients signifies that melanopsin luminance positively correlates with brightness magnitudes, and the cone luminance has two contribution components, one that is additive to melanopsin luminance and a second that is negative, implying an adaptation process. These results provide a new framework for evaluating the physiological basis of brightness perception and have direct practical applications for the development of energy-efficient light sources.
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31
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Wong JCY, Smyllie NJ, Banks GT, Pothecary CA, Barnard AR, Maywood ES, Jagannath A, Hughes S, van der Horst GTJ, MacLaren RE, Hankins MW, Hastings MH, Nolan PM, Foster RG, Peirson SN. Differential roles for cryptochromes in the mammalian retinal clock. FASEB J 2018; 32:4302-4314. [PMID: 29561690 PMCID: PMC6071063 DOI: 10.1096/fj.201701165rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cryptochromes 1 and 2 (CRY1/2) are key components of the negative limb of the mammalian circadian clock. Like many peripheral tissues, Cry1 and -2 are expressed in the retina, where they are thought to play a role in regulating rhythmic physiology. However, studies differ in consensus as to their localization and function, and CRY1 immunostaining has not been convincingly demonstrated in the retina. Here we describe the expression and function of CRY1 and -2 in the mouse retina in both sexes. Unexpectedly, we show that CRY1 is expressed throughout all retinal layers, whereas CRY2 is restricted to the photoreceptor layer. Retinal period 2::luciferase recordings from CRY1-deficient mice show reduced clock robustness and stability, while those from CRY2-deficient mice show normal, albeit long-period, rhythms. In functional studies, we then investigated well-defined rhythms in retinal physiology. Rhythms in the photopic electroretinogram, contrast sensitivity, and pupillary light response were all severely attenuated or abolished in CRY1-deficient mice. In contrast, these physiological rhythms are largely unaffected in mice lacking CRY2, and only photopic electroretinogram rhythms are affected. Together, our data suggest that CRY1 is an essential component of the mammalian retinal clock, whereas CRY2 has a more limited role.—Wong, J. C. Y., Smyllie, N. J., Banks, G. T., Pothecary, C. A., Barnard, A. R., Maywood, E. S., Jagannath, A., Hughes, S., van der Horst, G. T. J., MacLaren, R. E., Hankins, M. W., Hastings, M. H., Nolan, P. M., Foster, R. G., Peirson, S. N. Differential roles for cryptochromes in the mammalian retinal clock.
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Affiliation(s)
- Jovi C Y Wong
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | - Nicola J Smyllie
- Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Gareth T Banks
- Medical Research Council (MRC) Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Carina A Pothecary
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Elizabeth S Maywood
- Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Aarti Jagannath
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | - Steven Hughes
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | | | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Mark W Hankins
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | - Michael H Hastings
- Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Patrick M Nolan
- Medical Research Council (MRC) Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
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32
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De Silva SR, Barnard AR, Hughes S, Tam SKE, Martin C, Singh MS, Barnea-Cramer AO, McClements ME, During MJ, Peirson SN, Hankins MW, MacLaren RE. Long-term restoration of visual function in end-stage retinal degeneration using subretinal human melanopsin gene therapy. Proc Natl Acad Sci U S A 2017; 114:11211-11216. [PMID: 28973921 PMCID: PMC5651734 DOI: 10.1073/pnas.1701589114] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Optogenetic strategies to restore vision in patients who are blind from end-stage retinal degenerations aim to render remaining retinal cells light sensitive once photoreceptors are lost. Here, we assessed long-term functional outcomes following subretinal delivery of the human melanopsin gene (OPN4) in the rd1 mouse model of retinal degeneration using an adeno-associated viral vector. Ectopic expression of OPN4 using a ubiquitous promoter resulted in cellular depolarization and ganglion cell action potential firing. Restoration of the pupil light reflex, behavioral light avoidance, and the ability to perform a task requiring basic image recognition were restored up to 13 mo following injection. These data suggest that melanopsin gene therapy via a subretinal route may be a viable and stable therapeutic option for the treatment of end-stage retinal degeneration in humans.
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Affiliation(s)
- Samantha R De Silva
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Shu K E Tam
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Chris Martin
- Department of Psychology, The University of Sheffield, Sheffield S1 2LT, United Kingdom
| | - Mandeep S Singh
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Alona O Barnea-Cramer
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | | | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom;
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, National Institute for Health Research Biomedical Research Centre, Oxford OX3 9DU, United Kingdom;
- Moorfields Eye Hospital, National Institute for Health Research Biomedical Research Centre, London EC1V 2PD, United Kingdom
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33
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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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34
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Peirson SN, Brown LA, Pothecary CA, Benson LA, Fisk AS. Light and the laboratory mouse. J Neurosci Methods 2017; 300:26-36. [PMID: 28414048 PMCID: PMC5909038 DOI: 10.1016/j.jneumeth.2017.04.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 02/06/2023]
Abstract
Light exerts widespread effects on physiology and behaviour. As well as the widely-appreciated role of light in vision, light also plays a critical role in many non-visual responses, including regulating circadian rhythms, sleep, pupil constriction, heart rate, hormone release and learning and memory. In mammals, responses to light are all mediated via retinal photoreceptors, including the classical rods and cones involved in vision as well as the recently identified melanopsin-expressing photoreceptive retinal ganglion cells (pRGCs). Understanding the effects of light on the laboratory mouse therefore depends upon an appreciation of the physiology of these retinal photoreceptors, including their differing sens itivities to absolute light levels and wavelengths. The signals from these photoreceptors are often integrated, with different responses involving distinct retinal projections, making generalisations challenging. Furthermore, many commonly used laboratory mouse strains carry mutations that affect visual or non-visual physiology, ranging from inherited retinal degeneration to genetic differences in sleep and circadian rhythms. Here we provide an overview of the visual and non-visual systems before discussing practical considerations for the use of light for researchers and animal facility staff working with laboratory mice.
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Affiliation(s)
- Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom.
| | - Laurence A Brown
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| | - Carina A Pothecary
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| | - Lindsay A Benson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
| | - Angus S Fisk
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, United Kingdom
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35
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Yasin B, Kohn E, Peters M, Zaguri R, Weiss S, Schopf K, Katz B, Huber A, Minke B. Ectopic Expression of Mouse Melanopsin in Drosophila Photoreceptors Reveals Fast Response Kinetics and Persistent Dark Excitation. J Biol Chem 2017; 292:3624-3636. [PMID: 28119450 PMCID: PMC5339748 DOI: 10.1074/jbc.m116.754770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 01/19/2017] [Indexed: 01/10/2023] Open
Abstract
The intrinsically photosensitive M1 retinal ganglion cells (ipRGC) initiate non-image-forming light-dependent activities and express the melanopsin (OPN4) photopigment. Several features of ipRGC photosensitivity are characteristic of fly photoreceptors. However, the light response kinetics of ipRGC is much slower due to unknown reasons. Here we used transgenic Drosophila, in which the mouse OPN4 replaced the native Rh1 photopigment of Drosophila R1-6 photoreceptors, resulting in deformed rhabdomeric structure. Immunocytochemistry revealed OPN4 expression at the base of the rhabdomeres, mainly at the rhabdomeral stalk. Measurements of the early receptor current, a linear manifestation of photopigment activation, indicated large expression of OPN4 in the plasma membrane. Comparing the early receptor current amplitude and action spectra between WT and the Opn4-expressing Drosophila further indicated that large quantities of a blue absorbing photopigment were expressed, having a dark stable blue intermediate state. Strikingly, the light-induced current of the Opn4-expressing fly photoreceptors was ∼40-fold faster than that of ipRGC. Furthermore, an intense white flash induced a small amplitude prolonged dark current composed of discrete unitary currents similar to the Drosophila single photon responses. The induction of prolonged dark currents by intense blue light could be suppressed by a following intense green light, suggesting induction and suppression of prolonged depolarizing afterpotential. This is the first demonstration of heterologous functional expression of mammalian OPN4 in the genetically emendable Drosophila photoreceptors. Moreover, the fast OPN4-activated ionic current of Drosophila photoreceptors relative to that of mouse ipRGC, indicates that the slow light response of ipRGC does not arise from an intrinsic property of melanopsin.
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Affiliation(s)
- Bushra Yasin
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
| | - Elkana Kohn
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
| | - Maximilian Peters
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
| | - Rachel Zaguri
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
| | - Shirley Weiss
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
| | - Krystina Schopf
- the Department of Biosensorics, Institute of Physiology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Ben Katz
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
| | - Armin Huber
- the Department of Biosensorics, Institute of Physiology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Baruch Minke
- From the Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel and
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36
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Aptel F, Weinreb RN, Chiquet C, Mansouri K. 24-h monitoring devices and nyctohemeral rhythms of intraocular pressure. Prog Retin Eye Res 2016; 55:108-148. [PMID: 27477112 DOI: 10.1016/j.preteyeres.2016.07.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/07/2016] [Accepted: 07/12/2016] [Indexed: 01/26/2023]
Abstract
Intraocular pressure (IOP) is not a fixed value and varies over both the short term and periods lasting several months or years. In particular, IOP is known to vary throughout the 24-h period of a day, defined as a nyctohemeral rhythm in humans. In clinical practice, it is crucial to evaluate the changes in IOP over 24 h in several situations, including the diagnosis of ocular hypertension and glaucoma (IOP is often higher at night) and to optimize the therapeutic management of glaucoma. Until recently, all evaluations of 24-h IOP rhythm were performed using repeated IOP measurements, requiring individuals to be awakened for nocturnal measurements. This method may be imperfect, because it is not physiologic and disturbs the sleep architecture, and also because it provides a limited number of time point measurements not sufficient to finely asses IOP changes. These limitations may have biased previous descriptions of physiological IOP rhythm. Recently, extraocular and intraocular devices integrating a pressure sensor for continuous IOP monitoring have been developed and are available for use in humans. The objective of this article is to present the contributions of these new 24-h monitoring devices for the study of the nyctohemeral rhythms. In healthy subjects and untreated glaucoma subjects, a nyctohemeral rhythm is consistently found and frequently characterized by a mean diurnal IOP lower than the mean nocturnal IOP, with a diurnal bathyphase - usually in the middle or at the end of the afternoon - and a nocturnal acrophase, usually in the middle or at the end of the night.
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Affiliation(s)
- Florent Aptel
- Inserm U1042, Hypoxia and Physiopathology Laboratory, University Grenoble Alpes, Grenoble, France; Department of Ophthalmology, University Hospital, CHU Grenoble, Grenoble, France
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Center and Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA
| | - Christophe Chiquet
- Inserm U1042, Hypoxia and Physiopathology Laboratory, University Grenoble Alpes, Grenoble, France; Department of Ophthalmology, University Hospital, CHU Grenoble, Grenoble, France
| | - Kaweh Mansouri
- Glaucoma Center, Montchoisi Clinic, Swiss Vision Network, Lausanne, Switzerland; Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO, USA.
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37
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Arroyo DA, Kirkby LA, Feller MB. Retinal Waves Modulate an Intraretinal Circuit of Intrinsically Photosensitive Retinal Ganglion Cells. J Neurosci 2016; 36:6892-905. [PMID: 27358448 PMCID: PMC4926237 DOI: 10.1523/jneurosci.0572-16.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/11/2016] [Accepted: 05/16/2016] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Before the maturation of rod and cone photoreceptors, the developing retina relies on light detection by intrinsically photosensitive retinal ganglion cells (ipRGCs) to drive early light-dependent behaviors. ipRGCs are output neurons of the retina; however, they also form functional microcircuits within the retina itself. Whether ipRGC microcircuits exist during development and whether they influence early light detection remain unknown. Here, we investigate the neural circuit that underlies the ipRGC-driven light response in developing mice. We use a combination of calcium imaging, tracer coupling, and electrophysiology experiments to show that ipRGCs form extensive gap junction networks that strongly contribute to the overall light response of the developing retina. Interestingly, we found that gap junction coupling was modulated by spontaneous retinal waves, such that acute blockade of waves dramatically increased the extent of coupling and hence increased the number of light-responsive neurons. Moreover, using an optical sensor, we found that this wave-dependent modulation of coupling is driven by dopamine that is phasically released by retinal waves. Our results demonstrate that ipRGCs form gap junction microcircuits during development that are modulated by retinal waves; these circuits determine the extent of the light response and thus potentially impact the processing of early visual information and light-dependent developmental functions. SIGNIFICANCE STATEMENT Light-dependent functions in early development are mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). Here we show that ipRGCs form an extensive gap junction network with other retinal neurons, including other ipRGCs, which shapes the retina's overall light response. Blocking cholinergic retinal waves, which are the primary source of neural activity before maturation of photoreceptors, increased the extent of ipRGC gap junction networks, thus increasing the number of light-responsive cells. We determined that this modulation of ipRGC gap junction networks occurs via dopamine released by waves. These results demonstrate that retinal waves mediate dopaminergic modulation of gap junction networks to regulate pre-vision light responses.
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Affiliation(s)
| | | | - Marla B Feller
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California-Berkeley, Berkeley, California 94720-3200
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38
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Thompson CL, Selby CP, Van Gelder RN, Blaner WS, Lee J, Quadro L, Lai K, Gottesman ME, Sancar A. Effect of Vitamin A Depletion on Nonvisual Phototransduction Pathways in Cryptochromeless Mice. J Biol Rhythms 2016; 19:504-17. [PMID: 15523112 DOI: 10.1177/0748730404270519] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mice exhibit multiple nonvisual responses to light, including 1) photoentrainment of circadian rhythm; 2) “masking,” which refers to the acute effect of light on behavior, either negative (activity suppressing) or positive (activity inducing); and 3) pupillary constriction. In mammals, the eye is the sole photosensory organ for these responses, and it contains only 2 known classes of pigments: opsins and cryptochromes. No individual opsin or cryptochrome gene is essential for circadian photoreception, gene photoinduction, or masking. Previously, the authors found that mice lacking retinol-binding protein, in which dietary depletion of ocular retinaldehyde can be achieved, had normal light signaling to the SCN, as determined by per gene photoinduction. In the present study, the authors analyzed phototransduction to the SCN in vitamin A-replete and vitamin A-depleted rbp-/- and rbp-/-cry1-/-cry2-/- mice using molecular and behavioral end points. They found that vitamin A-depleted rbp-/- mice exhibit either normal photoentrainment or become diurnal. In contrast, while vitamin A-replete rbp-/-cry1-/-cry2-/- mice are light responsive (with reduced sensitivity), vitamin A-depleted rbp-/-cry1-/-cry2-/- mice, which presumably lack functional opsins and cryptochromes, lose most behavioral and molecular responses to light. These data demonstrate that both cryptochromes and opsins regulate nonvisual photoresponses.
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Affiliation(s)
- Carol L Thompson
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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39
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Meyer A, Tetenborg S, Greb H, Segelken J, Dorgau B, Weiler R, Hormuzdi SG, Janssen-Bienhold U, Dedek K. Connexin30.2: In Vitro Interaction with Connexin36 in HeLa Cells and Expression in AII Amacrine Cells and Intrinsically Photosensitive Ganglion Cells in the Mouse Retina. Front Mol Neurosci 2016; 9:36. [PMID: 27303262 PMCID: PMC4882342 DOI: 10.3389/fnmol.2016.00036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/09/2016] [Indexed: 11/13/2022] Open
Abstract
Electrical coupling via gap junctions is an abundant phenomenon in the mammalian retina and occurs in all major cell types. Gap junction channels are assembled from different connexin subunits, and the connexin composition of the channel confers specific properties to the electrical synapse. In the mouse retina, gap junctions were demonstrated between intrinsically photosensitive ganglion cells and displaced amacrine cells but the underlying connexin remained undetermined. In the primary rod pathway, gap junctions play a crucial role, coupling AII amacrine cells among each other and to ON cone bipolar cells. Although it has long been known that connexin36 and connexin45 are necessary for the proper functioning of this most sensitive rod pathway, differences between homocellular AII/AII gap junctions and AII/ON bipolar cell gap junctions suggested the presence of an additional connexin in AII amacrine cells. Here, we used a connexin30.2-lacZ mouse line to study the expression of connexin30.2 in the retina. We show that connexin30.2 is expressed in intrinsically photosensitive ganglion cells and AII amacrine cells. Moreover, we tested whether connexin30.2 and connexin36-both expressed in AII amacrine cells-are able to interact with each other and are deposited in the same gap junctional plaques. Using newly generated anti-connexin30.2 antibodies, we show in HeLa cells that both connexins are indeed able to interact and may form heteromeric channels: both connexins were co-immunoprecipitated from transiently transfected HeLa cells and connexin30.2 gap junction plaques became significantly larger when co-expressed with connexin36. These data suggest that connexin36 is able to form heteromeric gap junctions with another connexin. We hypothesize that co-expression of connexin30.2 and connexin36 may endow AII amacrine cells with the means to differentially regulate its electrical coupling to different synaptic partners.
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Affiliation(s)
- Arndt Meyer
- Department of Neuroscience and Neurobiology, University of Oldenburg Oldenburg, Germany
| | - Stephan Tetenborg
- Department of Neuroscience and Neurobiology, University of Oldenburg Oldenburg, Germany
| | - Helena Greb
- Department of Neuroscience and Neurobiology, University of Oldenburg Oldenburg, Germany
| | - Jasmin Segelken
- Department of Neuroscience and Neurobiology, University of Oldenburg Oldenburg, Germany
| | - Birthe Dorgau
- Department of Neuroscience and Neurobiology, University of Oldenburg Oldenburg, Germany
| | - Reto Weiler
- Department of Neuroscience and Neurobiology, University of OldenburgOldenburg, Germany; Research Center Neurosensory Science, University of OldenburgOldenburg, Germany
| | | | - Ulrike Janssen-Bienhold
- Department of Neuroscience and Neurobiology, University of OldenburgOldenburg, Germany; Research Center Neurosensory Science, University of OldenburgOldenburg, Germany
| | - Karin Dedek
- Department of Neuroscience and Neurobiology, University of OldenburgOldenburg, Germany; Research Center Neurosensory Science, University of OldenburgOldenburg, Germany
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Shirzad-Wasei N, DeGrip WJ. Heterologous expression of melanopsin: Present, problems and prospects. Prog Retin Eye Res 2016; 52:1-21. [DOI: 10.1016/j.preteyeres.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/25/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022]
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Spoida K, Eickelbeck D, Karapinar R, Eckhardt T, Mark MD, Jancke D, Ehinger BV, König P, Dalkara D, Herlitze S, Masseck OA. Melanopsin Variants as Intrinsic Optogenetic On and Off Switches for Transient versus Sustained Activation of G Protein Pathways. Curr Biol 2016; 26:1206-12. [PMID: 27068418 DOI: 10.1016/j.cub.2016.03.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/09/2016] [Accepted: 03/01/2016] [Indexed: 10/22/2022]
Abstract
G-protein-coupled receptors (GPCRs) represent the major protein family for cellular modulation in mammals. Therefore, various strategies have been developed to analyze the function of GPCRs involving pharmaco- and optogenetic approaches [1, 2]. However, a tool that combines precise control of the activation and deactivation of GPCR pathways and/or neuronal firing with limited phototoxicity is still missing. We compared the biophysical properties and optogenetic application of a human and a mouse melanopsin variant (hOpn4L and mOpn4L) on the control of Gi/o and Gq pathways in heterologous expression systems and mouse brain. We found that GPCR pathways can be switched on/off by blue/yellow light. The proteins differ in their kinetics and wavelength dependence to activate and deactivate G protein pathways. Whereas mOpn4L is maximally activated by very short light pulses, leading to sustained G protein activation, G protein responses of hOpn4L need longer light pulses to be activated and decline in amplitude. Based on the different biophysical properties, brief light activation of mOpn4L is sufficient to induce sustained neuronal firing in cerebellar Purkinje cells (PC), whereas brief light activation of hOpn4L induces AP firing, which declines in frequency over time. Most importantly, mOpn4L-induced sustained firing can be switched off by yellow light. Based on the biophysical properties, hOpn4L and mOpn4L represent the first GPCR optogenetic tools, which can be used to switch GPCR pathways/neuronal firing on an off with temporal precision and limited phototoxicity. We suggest to name these tools moMo and huMo for future optogenetic applications.
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Affiliation(s)
- Katharina Spoida
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Dennis Eickelbeck
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Raziye Karapinar
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Tobias Eckhardt
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Melanie D Mark
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Dirk Jancke
- Optical Imaging Group, Institut für Neuroinformatik, NB 2/27, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Benedikt Valerian Ehinger
- Institute of Cognitive Science, University of Osnabrück, Albrechtstrasse 28, 49076 Osnabrück, Germany
| | - Peter König
- Institute of Cognitive Science, University of Osnabrück, Albrechtstrasse 28, 49076 Osnabrück, Germany; Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Deniz Dalkara
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Institut de la Vision, 17 Rue Moreau, 75012 Paris, France
| | - Stefan Herlitze
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany.
| | - Olivia A Masseck
- Department of General Zoology and Neurobiology, ND 7/31, Ruhr University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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Hughes S, Jagannath A, Rodgers J, Hankins MW, Peirson SN, Foster RG. Signalling by melanopsin (OPN4) expressing photosensitive retinal ganglion cells. Eye (Lond) 2016; 30:247-54. [PMID: 26768919 DOI: 10.1038/eye.2015.264] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 11/23/2015] [Indexed: 12/17/2022] Open
Abstract
Over the past two decades there have been significant advances in our understanding of both the anatomy and function of the melanopsin system. It has become clear that rather than acting as a simple irradiance detector the melanopsin system is in fact far more complicated. The range of behavioural systems known to be influenced by melanopsin activity is increasing with time, and it is now clear that melanopsin contributes not only to multiple non-image forming systems but also has a role in visual pathways. How melanopsin is capable of driving so many different behaviours is unclear, but recent evidence suggests that the answer may lie in the diversity of melanopsin light responses and the functional specialisation of photosensitive retinal ganglion cell (pRGC) subtypes. In this review, we shall overview the current understanding of the melanopsin system, and evaluate the evidence for the hypothesis that individual pRGC subtypes not only perform specific roles, but are functionally specialised to do so. We conclude that while, currently, the available data somewhat support this hypothesis, we currently lack the necessary detail to fully understand how the functional diversity of pRGC subtypes correlates with different behavioural responses, and ultimately why such complexity is required within the melanopsin system. What we are lacking is a cohesive understanding of how light responses differ between the pRGC subtypes (based not only on anatomical classification but also based on their site of innervation); how these diverse light responses are generated, and most importantly how these responses relate to the physiological functions they underpin.
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Affiliation(s)
- S Hughes
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - A Jagannath
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - J Rodgers
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - M W Hankins
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - S N Peirson
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - R G Foster
- Nuffield Laboratory of Ophthalmology (Nuffield Department of Clinical Neurosciences), Sleep and Circadian Neuroscience Institute, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Poletini MO, Moraes MN, Ramos BC, Jerônimo R, Castrucci AMDL. TRP channels: a missing bond in the entrainment mechanism of peripheral clocks throughout evolution. Temperature (Austin) 2015; 2:522-34. [PMID: 27227072 PMCID: PMC4843991 DOI: 10.1080/23328940.2015.1115803] [Citation(s) in RCA: 260] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/10/2015] [Accepted: 10/29/2015] [Indexed: 11/03/2022] Open
Abstract
Circadian rhythm may be understood as a temporal organization that works to orchestrate physiological processes and behavior in a period of approximately 24 h. Because such temporal organization has evolved in the presence of predictable environmental clues, such as day length, tides, seasons, and temperature, the organism has confronted the natural selection in highly precise intervals of opportunities and risks, generating temporal programs and resetting mechanisms, which are well conserved among different taxa of animals. The present review brings some evidence of how these programs may have co-evolved in systems able to deal with 2 or more environmental clues, and how they similarly function in different group of animals, stressing how important temperature and light were to establish the temporal organizations. For example, melanopsin and rhodopsin, photopigments present respectively in circadian and visual photoreceptors, are required for temperature discrimination in Drosophila melanogaster. These pigments may signal light and temperature via activation of cationic membrane channel, named transient-receptor potential channel (TRP). In fact, TRPs have been suggested to function as thermal sensor for various groups of animals. Another example is the clock machinery at the molecular level. A set of very-well conserved proteins, known as clock proteins, function as transcription factors in positive and negative auto-regulatory loops generating circadian changes of their expression, and of clock-controlled genes. Similar molecular machinery is present in organisms as diverse as cyanobacteria (Synechococcus), fungi (Neurospora), insects (Drosophila), and vertebrates including humans.
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Affiliation(s)
- Maristela O Poletini
- Department of Physiology and Biophysics; Institute of Biological Sciences; Federal University of Minas Gerais ; Belo Horizonte, Brazil
| | - Maria Nathália Moraes
- Department of Physiology; Institute of Biosciences; University of Sao Paulo ; São Paulo, Brazil
| | - Bruno César Ramos
- Department of Physiology; Institute of Biosciences; University of Sao Paulo ; São Paulo, Brazil
| | - Rodrigo Jerônimo
- Department of Physiology; Institute of Biosciences; University of Sao Paulo ; São Paulo, Brazil
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Díaz NM, Morera LP, Guido ME. Melanopsin and the Non-visual Photochemistry in the Inner Retina of Vertebrates. Photochem Photobiol 2015; 92:29-44. [DOI: 10.1111/php.12545] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/09/2015] [Indexed: 01/28/2023]
Affiliation(s)
- Nicolás M. Díaz
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
| | - Luis P. Morera
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
| | - Mario E. Guido
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
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45
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All spiking, sustained ON displaced amacrine cells receive gap-junction input from melanopsin ganglion cells. Curr Biol 2015; 25:2763-2773. [PMID: 26441349 DOI: 10.1016/j.cub.2015.09.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/15/2015] [Accepted: 09/05/2015] [Indexed: 11/22/2022]
Abstract
Retinal neurons exhibit sustained versus transient light responses, which are thought to encode low- and high-frequency stimuli, respectively. This dichotomy has been recognized since the earliest intracellular recordings from the 1960s, but the underlying mechanisms are not yet fully understood. We report that in the ganglion cell layer of rat retinas, all spiking amacrine interneurons with sustained ON photoresponses receive gap-junction input from intrinsically photosensitive retinal ganglion cells (ipRGCs), recently discovered photoreceptors that specialize in prolonged irradiance detection. This input presumably allows ipRGCs to regulate the secretion of neuromodulators from these interneurons. We have identified three morphological varieties of such ipRGC-driven displaced amacrine cells: (1) monostratified cells with dendrites terminating exclusively in sublamina S5 of the inner plexiform layer, (2) bistratified cells with dendrites in both S1 and S5, and (3) polyaxonal cells with dendrites and axons stratifying in S5. Most of these amacrine cells are wide field, although some are medium field. The three classes respond to light differently, suggesting that they probably perform diverse functions. These results demonstrate that ipRGCs are a major source of tonic visual information within the retina and exert widespread intraretinal influence. They also add to recent evidence that ganglion cells signal not only to the brain.
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Silva-Urra JA, Núñez-Espinosa CA, Niño-Mendez OA, Gaitán-Peñas H, Altavilla C, Toro-Salinas A, Torrella JR, Pagès T, Javierre CF, Behn C, Viscor G. Circadian and Sex Differences After Acute High-Altitude Exposure: Are Early Acclimation Responses Improved by Blue Light? Wilderness Environ Med 2015; 26:459-71. [PMID: 26254125 DOI: 10.1016/j.wem.2015.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 04/30/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The possible effects of blue light during acute hypoxia and the circadian rhythm on several physiological and cognitive parameters were studied. METHODS Fifty-seven volunteers were randomly assigned to 2 groups: nocturnal (2200-0230 hours) or diurnal (0900-1330 hours) and exposed to acute hypoxia (4000 m simulated altitude) in a hypobaric chamber. The participants were illuminated by blue LEDs or common artificial light on 2 different days. During each session, arterial oxygen saturation (Spo2), blood pressure, heart rate variability, and cognitive parameters were measured at sea level, after reaching the simulated altitude of 4000 m, and after 3 hours at this altitude. RESULTS The circadian rhythm caused significant differences in blood pressure and heart rate variability. A 4% to 9% decrease in waking nocturnal Spo2 under acute hypoxia was observed. Acute hypoxia also induced a significant reduction (4%-8%) in systolic pressure, slightly more marked (up to 13%) under blue lighting. Women had significantly increased systolic (4%) and diastolic (12%) pressures under acute hypoxia at night compared with daytime pressure; this was not observed in men. Some tendencies toward better cognitive performance (d2 attention test) were seen under blue illumination, although when considered together with physiological parameters and reaction time, there was no conclusive favorable effect of blue light on cognitive fatigue suppression after 3 hours of acute hypobaric hypoxia. CONCLUSIONS It remains to be seen whether longer exposure to blue light under hypobaric hypoxic conditions would induce favorable effects against fatigue.
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Affiliation(s)
- Juan A Silva-Urra
- Departamento Biomédico, Universidad de Antofagasta, Antofagasta, Chile
| | | | - Oscar A Niño-Mendez
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona, Spain
| | | | | | | | | | | | - Casimiro F Javierre
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona, Spain
| | - Claus Behn
- Laboratorio de Ambientes Extremos (ICBM), Universidad de Chile, Santiago de Chile, Chile
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Procyk CA, Eleftheriou CG, Storchi R, Allen AE, Milosavljevic N, Brown TM, Lucas RJ. Spatial receptive fields in the retina and dorsal lateral geniculate nucleus of mice lacking rods and cones. J Neurophysiol 2015; 114:1321-30. [PMID: 26084909 PMCID: PMC4725120 DOI: 10.1152/jn.00368.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 06/12/2015] [Indexed: 02/06/2023] Open
Abstract
In advanced retinal degeneration loss of rods and cones leaves melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) as the only source of visual information. ipRGCs drive non-image-forming responses (e.g., circadian photoentrainment) under such conditions but, despite projecting to the primary visual thalamus [dorsal lateral geniculate nucleus (dLGN)], do not support form vision. We wished to determine what precludes ipRGCs supporting spatial discrimination after photoreceptor loss, using a mouse model (rd/rd cl) lacking rods and cones. Using multielectrode arrays, we found that both RGCs and neurons in the dLGN of this animal have clearly delineated spatial receptive fields. In the retina, they are typically symmetrical, lack inhibitory surrounds, and have diameters in the range of 10-30° of visual space. Receptive fields in the dLGN were larger (diameters typically 30-70°) but matched the retinotopic map of the mouse dLGN. Injections of a neuroanatomical tracer (cholera toxin β-subunit) into the dLGN confirmed that retinotopic order of ganglion cell projections to the dLGN and thalamic projections to the cortex is at least superficially intact in rd/rd cl mice. However, as previously reported for deafferented ipRGCs, onset and offset of light responses have long latencies in the rd/rd cl retina and dLGN. Accordingly, dLGN neurons failed to track dynamic changes in light intensity in this animal. Our data reveal that ipRGCs can convey spatial information in advanced retinal degeneration and identify their poor temporal fidelity as the major limitation in their ability to provide information about spatial patterns under natural viewing conditions.
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Affiliation(s)
| | - Cyril G Eleftheriou
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Riccardo Storchi
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Annette E Allen
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Nina Milosavljevic
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Timothy M Brown
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Robert J Lucas
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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Tan K, An L, Wang SM, Wang XD, Zhang ZN, Miao K, Sui LL, He SZ, Nie JZ, Wu ZH, Tian JH. Actin Disorganization Plays a Vital Role in Impaired Embryonic Development of In Vitro-Produced Mouse Preimplantation Embryos. PLoS One 2015; 10:e0130382. [PMID: 26076347 PMCID: PMC4468147 DOI: 10.1371/journal.pone.0130382] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/19/2015] [Indexed: 02/04/2023] Open
Abstract
Assisted reproductive technology (ART) is being increasingly applied to overcome infertility. However, the in vitro production process, the main procedure of ART, can lead to aberrant embryonic development and health-related problems in offspring. Understanding the mechanisms underlying the ART-induced side effects is important to improve the ART process. In this study, we carried out comparative transcriptome profiling between in vivo- (IVO) and in vitro- produced (IVP) mouse blastocysts. Our results suggested that aberrant actin organization might be a major factor contributing to the impaired development of IVP embryos. To test this, we examined the effect of actin disorganization on the development of IVP preimplantation embryos. Specific disruption of actin organization by cytochalasin B (CB) indicated that well-organized actin is essential for in vitro embryonic development. Supplementing the culture medium with 10–9 M melatonin, a cytoskeletal modulator in adult somatic cells, significantly reversed the disrupted expression patterns of genes related to actin organization, including Arhgef2, Bcl2, Coro2b, Flnc, and Palld. Immunofluorescence analysis showed that melatonin treatment of IVP embryos significantly improved the distribution and organization of actin filaments (F-actin) from the 8-cell stage onwards. More importantly, we found that melatonin alleviated the CB-mediated aberrant F-actin distribution and organization and rescued CB-induced impaired embryonic development. This is the first study to indicate that actin disorganization is implicated in impaired development of IVP embryos during the preimplantation stage. We also demonstrated that improving actin organization is a promising strategy to optimize existing IVP systems.
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Affiliation(s)
- Kun Tan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Lei An
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Shu-Min Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Xiao-Dong Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Zhen-Ni Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Kai Miao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Lin-Lin Sui
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Shu-Zhi He
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Jing-Zhou Nie
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Zhong-Hong Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
| | - Jian-Hui Tian
- Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China
- * E-mail:
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49
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García-Fernández JM, Cernuda-Cernuda R, Davies WIL, Rodgers J, Turton M, Peirson SN, Follett BK, Halford S, Hughes S, Hankins MW, Foster RG. The hypothalamic photoreceptors regulating seasonal reproduction in birds: a prime role for VA opsin. Front Neuroendocrinol 2015; 37:13-28. [PMID: 25448788 DOI: 10.1016/j.yfrne.2014.11.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 10/25/2014] [Accepted: 11/02/2014] [Indexed: 01/30/2023]
Abstract
Extraretinal photoreceptors located within the medio-basal hypothalamus regulate the photoperiodic control of seasonal reproduction in birds. An action spectrum for this response describes an opsin photopigment with a λmax of ∼ 492 nm. Beyond this however, the specific identity of the photopigment remains unresolved. Several candidates have emerged including rod-opsin; melanopsin (OPN4); neuropsin (OPN5); and vertebrate ancient (VA) opsin. These contenders are evaluated against key criteria used routinely in photobiology to link orphan photopigments to specific biological responses. To date, only VA opsin can easily satisfy all criteria and we propose that this photopigment represents the prime candidate for encoding daylength and driving seasonal breeding in birds. We also show that VA opsin is co-expressed with both gonadotropin-releasing hormone (GnRH) and arginine-vasotocin (AVT) neurons. These new data suggest that GnRH and AVT neurosecretory pathways are endogenously photosensitive and that our current understanding of how these systems are regulated will require substantial revision.
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Affiliation(s)
- José M García-Fernández
- Departamento de Morfología y Biología Celular, Universidad de Oviedo, INEUROPA (Instituto de Neurociencias del Principado de Asturias), Spain
| | - Rafael Cernuda-Cernuda
- Departamento de Morfología y Biología Celular, Universidad de Oviedo, INEUROPA (Instituto de Neurociencias del Principado de Asturias), Spain
| | - Wayne I L Davies
- School of Animal Biology and University of Western Australia Oceans Institute, University of Western Australia, Perth, Western Australia, Australia
| | - Jessica Rodgers
- Sleep and Circadian Neuroscience Institute, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Michael Turton
- Sleep and Circadian Neuroscience Institute, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Brian K Follett
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.eNuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Steven Hughes
- Sleep and Circadian Neuroscience Institute, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Mark W Hankins
- Sleep and Circadian Neuroscience Institute, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom
| | - Russell G Foster
- Sleep and Circadian Neuroscience Institute, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, United Kingdom.
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Hughes S, Jagannath A, Hankins MW, Foster RG, Peirson SN. Photic regulation of clock systems. Methods Enzymol 2014; 552:125-43. [PMID: 25707275 DOI: 10.1016/bs.mie.2014.10.018] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Circadian rhythms in physiology and behavior provide a selective advantage by enabling organisms to anticipate rhythmic changes in their environment. These rhythms are based upon a molecular clock generated via an intracellular transcriptional-translational feedback loop involving a number of key clock genes. However, to be of practical use, circadian rhythms need to be entrained to the external environment. In mammals, the primary signal for entrainment is light detected by the photoreceptors of the eye. Research on the mechanisms of photic entrainment has identified a novel photoreceptor system in the retina, consisting of photosensitive retinal ganglion cells expressing the photopigment melanopsin. Light input from these retinal photoreceptors reaches the master circadian pacemaker in the suprachiasmatic nuclei (SCN) via the retinohypothalamic tract, where it then interacts with the molecular clock to bring about entrainment. This chapter focuses on the retinal photoreceptors mediating entrainment, and how light information from the retina is transmitted to the SCN, before detailing recent advances in our understanding of how the molecular clock within the SCN is regulated by light input. Finally, the primary assays that have been used to measure photic entrainment are described.
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Affiliation(s)
- Steven Hughes
- Sleep and Circadian Institute (SCNi), Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Oxford, United Kingdom
| | - Aarti Jagannath
- Sleep and Circadian Institute (SCNi), Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Oxford, United Kingdom
| | - Mark W Hankins
- Sleep and Circadian Institute (SCNi), Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Oxford, United Kingdom
| | - Russell G Foster
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
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