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Li S, Jin M. Ablation of Fatty Acid Transport Protein-4 Enhances Cone Survival, M-cone Vision, and Synthesis of Cone-Tropic 9- cis-Retinal in rd12 Mouse Model of Leber Congenital Amaurosis. J Neurosci 2024; 44:e1994232024. [PMID: 38811164 PMCID: PMC11223470 DOI: 10.1523/jneurosci.1994-23.2024] [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: 10/12/2023] [Revised: 12/03/2023] [Accepted: 05/22/2024] [Indexed: 05/31/2024] Open
Abstract
The canonical visual cycle employing RPE65 as the retinoid isomerase regenerates 11-cis-retinal to support both rod- and cone-mediated vision. Mutations of RPE65 are associated with Leber congenital amaurosis that results in rod and cone photoreceptor degeneration and vision loss of affected patients at an early age. Dark-reared Rpe65-/- mouse has been known to form isorhodopsin that employs 9-cis-retinal as the photosensitive chromophore. The mechanism regulating 9-cis-retinal synthesis and the role of the endogenous 9-cis-retinal in cone survival and function remain largely unknown. In this study, we found that ablation of fatty acid transport protein-4 (FATP4), a negative regulator of 11-cis-retinol synthesis catalyzed by RPE65, increased the formation of 9-cis-retinal, but not 11-cis-retinal, in a light-independent mechanism in both sexes of RPE65-null rd12 mice. Both rd12 and rd12;Fatp4-/- mice contained a massive amount of all-trans-retinyl esters in the eyes, exhibiting comparable scotopic vision and rod degeneration. However, expression levels of M- and S-opsins as well as numbers of M- and S-cones surviving in the superior retinas of rd12;Fatp4-/ - mice were at least twofold greater than those in age-matched rd12 mice. Moreover, FATP4 deficiency significantly shortened photopic b-wave implicit time, improved M-cone visual function, and substantially deaccelerated the progression of cone degeneration in rd12 mice, whereas FATP4 deficiency in mice with wild-type Rpe65 alleles neither induced 9-cis-retinal formation nor influenced cone survival and function. These results identify FATP4 as a new regulator of synthesis of 9-cis-retinal, which is a "cone-tropic" chromophore supporting cone survival and function in the retinas with defective RPE65.
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Affiliation(s)
- Songhua Li
- Neuroscience Center, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana 70112
| | - Minghao Jin
- Neuroscience Center, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana 70112
- Department of Ophthalmology, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana 70112
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Mouland JW, Watson AJ, Martial FP, Lucas RJ, Brown TM. Colour and melanopsin mediated responses in the murine retina. Front Cell Neurosci 2023; 17:1114634. [PMID: 36993934 PMCID: PMC10040579 DOI: 10.3389/fncel.2023.1114634] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/17/2023] [Indexed: 03/15/2023] Open
Abstract
Introduction: Intrinsically photosensitive retinal ganglion cells (ipRGCs) integrate melanopsin and rod/cone-mediated inputs to signal to the brain. Whilst originally identified as a cell type specialised for encoding ambient illumination, several lines of evidence indicate a strong association between colour discrimination and ipRGC-driven responses. Thus, cone-mediated colour opponent responses have been widely found across ipRGC target regions in the mouse brain and influence a key ipRGC-dependent function, circadian photoentrainment. Although ipRGCs exhibiting spectrally opponent responses have also been identified, the prevalence of such properties have not been systematically evaluated across the mouse retina or yet been found in ipRGC subtypes known to influence the circadian system. Indeed, there is still uncertainty around the overall prevalence of cone-dependent colour opponency across the mouse retina, given the strong retinal gradient in S and M-cone opsin (co)-expression and overlapping spectral sensitivities of most mouse opsins.Methods: To address this, we use photoreceptor isolating stimuli in multielectrode recordings from human red cone opsin knock-in mouse (Opn1mwR) retinas to systematically survey cone mediated responses and the occurrence of colour opponency across ganglion cell layer (GCL) neurons and identify ipRGCs based on spectral comparisons and/or the persistence of light responses under synaptic blockade.Results: Despite detecting robust cone-mediated responses across the retina, we find cone opponency is rare, especially outside of the central retina (overall ~3% of GCL neurons). In keeping with previous suggestions we also see some evidence of rod-cone opponency (albeit even more rare under our experimental conditions), but find no evidence for any enrichment of cone (or rod) opponent responses among functionally identified ipRGCs.Conclusion: In summary, these data suggest the widespread appearance of cone-opponency across the mouse early visual system and ipRGC-related responses may be an emergent feature of central visual processing mechanisms.
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Affiliation(s)
- Joshua W. Mouland
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- *Correspondence: Joshua W. Mouland
| | - Alex J. Watson
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Franck P. Martial
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Robert J. Lucas
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Timothy M. Brown
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
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Lindovsky J, Palkova M, Symkina V, Raishbrook MJ, Prochazka J, Sedlacek R. OCT and ERG Techniques in High-Throughput Phenotyping of Mouse Vision. Genes (Basel) 2023; 14:genes14020294. [PMID: 36833221 PMCID: PMC9956909 DOI: 10.3390/genes14020294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
The purpose of the study is to demonstrate coherent optical tomography and electroretinography techniques adopted from the human clinical practice to assess the morphology and function of the mouse retina in a high-throughput phenotyping environment. We present the normal range of wild-type C57Bl/6NCrl retinal parameters in six age groups between 10 and 100 weeks as well as examples of mild and severe pathologies resulting from knocking out a single protein-coding gene. We also show example data obtained by more detailed analysis or additional methods useful in eye research, for example, the angiography of a superficial and deep vascular complex. We discuss the feasibility of these techniques in conditions demanding a high-throughput approach such as the systemic phenotyping carried out by the International Mouse Phenotyping Consortium.
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Oosthuizen MK, Bennett NC. Clocks Ticking in the Dark: A Review of Biological Rhythms in Subterranean African Mole-Rats. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.878533] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biological rhythms are rhythmic fluctuations of biological functions that occur in almost all organisms and on several time scales. These rhythms are generated endogenously and entail the coordination of physiological and behavioural processes to predictable, external environmental rhythms. The light-dark cycle is usually the most prominent environmental cue to which animals synchronise their rhythms. Biological rhythms are believed to provide an adaptive advantage to organisms. In the present review, we will examine the occurrence of circadian and seasonal rhythms in African mole-rats (family Bathyergidae). African mole-rats are strictly subterranean, they very rarely emerge aboveground and therefore, do not have regular access to environmental light. A key adaptation to their specialised habitat is a reduction in the visual system. Mole-rats exhibit both daily and seasonal rhythmicity in a range of behaviours and physiological variables, albeit to different degrees and with large variability. We review previous research on the entire circadian system of African mole-rats and discuss output rhythms in detail. Laboratory experiments imply that light remains the strongest zeitgeber for entrainment but in the absence of light, animals can entrain to ambient temperature rhythms. Field studies report that rhythmic daily and seasonal behaviour is displayed in their natural habitat. We suggest that ambient temperature and rainfall play an important role in the timing of rhythmic behaviour in mole-rats, and that they likely respond directly to these zeitgebers in the field rather than exhibit robust endogenous rhythms. In the light of climate change, these subterranean animals are buffered from the direct and immediate effects of changes in temperature and rainfall, partly because they do not have robust circadian rhythms, however, on a longer term they are vulnerable to changes in their food sources and dispersal abilities.
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Tashiro JH, Ventura DF, Hauzman E. Morphological Plasticity of the Retina of Viperidae Snakes Is Associated With Ontogenetic Changes in Ecology and Behavior. Front Neuroanat 2022; 15:770804. [PMID: 35153683 PMCID: PMC8825375 DOI: 10.3389/fnana.2021.770804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
Snakes of the Viperidae family have retinas adapted to low light conditions, with high packaging of rod-photoreceptors containing the rhodopsin photopigment (RH1), and three types of cone-photoreceptors, large single and double cones with long-wavelength sensitive opsins (LWS), and small single cones with short-wavelength sensitive opsins (SWS1). In this study, we compared the density and distribution of photoreceptors and ganglion cell layer (GCL) cells in whole-mounted retinas of two viperid snakes, the lancehead Bothrops jararaca and the rattlesnake Crotalus durissus, and we estimated the upper limits of spatial resolving power based on anatomical data. The ground-dwelling C. durissus inhabits savannah-like habitats and actively searches for places to hide before using the sit-and-wait hunting strategy to ambush rodents. B. jararaca inhabits forested areas and has ontogenetic changes in ecology and behavior. Adults are terrestrial and use similar hunting strategies to those used by rattlesnakes to prey on rodents. Juveniles are semi-arboreal and use the sit-and-wait strategy and caudal luring to attract ectothermic prey. Our analyses showed that neuronal densities were similar for the two species, but their patterns of distribution were different between and within species. In adults and juveniles of C. durissus, cones were distributed in poorly defined visual streaks and rods were concentrated in the dorsal retina, indicating higher sensitivity in the lower visual field. In adults of B. jararaca, both cones and rods were distributed in poorly defined visual streaks, while in juveniles, rods were concentrated in the dorsal retina and cones in the ventral retina, enhancing sensitivity in the lower visual field and visual acuity in the upper field. The GCL cells had peak densities in the temporal retina of C. durissus and adults of B. jararaca, indicating higher acuity in the frontal field. In juveniles of B. jararaca, the peak density of GCL cells in the ventral retina indicates better acuity in the upper field. The estimated visual acuity varied from 2.3 to 2.8 cycles per degree. Our results showed interspecific differences and suggest ontogenetic plasticity of the retinal architecture associated with changes in the niche occupied by viperid snakes, and highlight the importance of the retinal topography for visual ecology and behavior of snakes.
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Tkatchenko TV, Tkatchenko AV. Genome-wide analysis of retinal transcriptome reveals common genetic network underlying perception of contrast and optical defocus detection. BMC Med Genomics 2021; 14:153. [PMID: 34107987 PMCID: PMC8190860 DOI: 10.1186/s12920-021-01005-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/04/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Refractive eye development is regulated by optical defocus in a process of emmetropization. Excessive exposure to negative optical defocus often leads to the development of myopia. However, it is still largely unknown how optical defocus is detected by the retina. METHODS Here, we used genome-wide RNA-sequencing to conduct analysis of the retinal gene expression network underlying contrast perception and refractive eye development. RESULTS We report that the genetic network subserving contrast perception plays an important role in optical defocus detection and emmetropization. Our results demonstrate an interaction between contrast perception, the retinal circadian clock pathway and the signaling pathway underlying optical defocus detection. We also observe that the relative majority of genes causing human myopia are involved in the processing of optical defocus. CONCLUSIONS Together, our results support the hypothesis that optical defocus is perceived by the retina using contrast as a proxy and provide new insights into molecular signaling underlying refractive eye development.
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Affiliation(s)
| | - Andrei V. Tkatchenko
- Department of Ophthalmology, Columbia University, New York, NY USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY USA
- Edward S. Harkness Eye Institute, Research Annex Room 415, 635 W. 165th Street, New York, NY 10032 USA
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7
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McNerney C, Johnston RJ. Thyroid hormone signaling specifies cone photoreceptor subtypes during eye development: Insights from model organisms and human stem cell-derived retinal organoids. VITAMINS AND HORMONES 2021; 116:51-90. [PMID: 33752828 DOI: 10.1016/bs.vh.2021.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Cones are the color-detecting photoreceptors of the vertebrate eye. Cones are specialized into subtypes whose functions are determined by the expression of color-sensitive opsin proteins. Organisms differ greatly in the number and patterning of cone subtypes. Despite these differences, thyroid hormone is an important regulator of opsin expression in most vertebrates. In this chapter, we outline how the timing of thyroid hormone signaling controls cone subtype fates during retinal development. We first examine our current understanding of cone subtype specification in model organisms and then describe advances in human stem cell-derived organoid technology that identified mechanisms controlling development of the human retina.
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Affiliation(s)
- Christina McNerney
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States.
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8
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Walbeek TJ, Harrison EM, Gorman MR, Glickman GL. Naturalistic Intensities of Light at Night: A Review of the Potent Effects of Very Dim Light on Circadian Responses and Considerations for Translational Research. Front Neurol 2021; 12:625334. [PMID: 33597916 PMCID: PMC7882611 DOI: 10.3389/fneur.2021.625334] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/06/2021] [Indexed: 12/16/2022] Open
Abstract
In this review, we discuss the remarkable potency and potential applications of a form of light that is often overlooked in a circadian context: naturalistic levels of dim light at night (nLAN), equivalent to intensities produced by the moon and stars. It is often assumed that such low levels of light do not produce circadian responses typically associated with brighter light levels. A solid understanding of the impacts of very low light levels is complicated further by the broad use of the somewhat ambiguous term “dim light,” which has been used to describe light levels ranging seven orders of magnitude. Here, we lay out the argument that nLAN exerts potent circadian effects on numerous mammalian species, and that given conservation of anatomy and function, the efficacy of light in this range in humans warrants further investigation. We also provide recommendations for the field of chronobiological research, including minimum requirements for the measurement and reporting of light, standardization of terminology (specifically as it pertains to “dim” light), and ideas for reconsidering old data and designing new studies.
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Affiliation(s)
- Thijs J Walbeek
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States.,Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR, United States
| | - Elizabeth M Harrison
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States
| | - Michael R Gorman
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States.,Department of Psychology, University of California, San Diego, San Diego, CA, United States
| | - Gena L Glickman
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, United States.,Departments of Psychiatry and Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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9
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Abstract
A retina completely devoid of topographic variations would be homogenous, encoding any given feature uniformly across the visual field. In a naive view, such homogeneity would appear advantageous. However, it is now clear that retinal topographic variations exist across mammalian species in a variety of forms and patterns. We briefly review some of the more established topographic variations in retinas of different mammalian species and focus on the recent discovery that cells belonging to a single neuronal subtype may exhibit distinct topographic variations in distribution, morphology, and even function. We concentrate on the mouse retina-originally viewed as homogenous-in which genetic labeling of distinct neuronal subtypes and other advanced techniques have revealed unexpected anatomical and physiological topographic variations. Notably, different subtypes reveal different patterns of nonuniformity, which may even be opposite or orthogonal to one another. These topographic variations in the encoding of visual space should be considered when studying visual processing in the retina and beyond.
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Affiliation(s)
- Alina Sophie Heukamp
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 7610001, Israel; , ,
| | - Rebekah Anne Warwick
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 7610001, Israel; , ,
| | - Michal Rivlin-Etzion
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 7610001, Israel; , ,
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10
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Nadal-Nicolás FM, Kunze VP, Ball JM, Peng BT, Krishnan A, Zhou G, Dong L, Li W. True S-cones are concentrated in the ventral mouse retina and wired for color detection in the upper visual field. eLife 2020; 9:e56840. [PMID: 32463363 PMCID: PMC7308094 DOI: 10.7554/elife.56840] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/28/2020] [Indexed: 12/25/2022] Open
Abstract
Color, an important visual cue for survival, is encoded by comparing signals from photoreceptors with different spectral sensitivities. The mouse retina expresses a short wavelength-sensitive and a middle/long wavelength-sensitive opsin (S- and M-opsin), forming opposing, overlapping gradients along the dorsal-ventral axis. Here, we analyzed the distribution of all cone types across the entire retina for two commonly used mouse strains. We found, unexpectedly, that 'true S-cones' (S-opsin only) are highly concentrated (up to 30% of cones) in ventral retina. Moreover, S-cone bipolar cells (SCBCs) are also skewed towards ventral retina, with wiring patterns matching the distribution of true S-cones. In addition, true S-cones in the ventral retina form clusters, which may augment synaptic input to SCBCs. Such a unique true S-cone and SCBC connecting pattern forms a basis for mouse color vision, likely reflecting evolutionary adaptation to enhance color coding for the upper visual field suitable for mice's habitat and behavior.
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Affiliation(s)
- Francisco M Nadal-Nicolás
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Vincent P Kunze
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - John M Ball
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Brian T Peng
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Akshay Krishnan
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Gaohui Zhou
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Lijin Dong
- Genetic Engineering Facility, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of HealthBethesdaUnited States
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Eldred KC, Avelis C, Johnston RJ, Roberts E. Modeling binary and graded cone cell fate patterning in the mouse retina. PLoS Comput Biol 2020; 16:e1007691. [PMID: 32150546 PMCID: PMC7082072 DOI: 10.1371/journal.pcbi.1007691] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 03/19/2020] [Accepted: 01/27/2020] [Indexed: 12/20/2022] Open
Abstract
Nervous systems are incredibly diverse, with myriad neuronal subtypes defined by gene expression. How binary and graded fate characteristics are patterned across tissues is poorly understood. Expression of opsin photopigments in the cone photoreceptors of the mouse retina provides an excellent model to address this question. Individual cones express S-opsin only, M-opsin only, or both S-opsin and M-opsin. These cell populations are patterned along the dorsal-ventral axis, with greater M-opsin expression in the dorsal region and greater S-opsin expression in the ventral region. Thyroid hormone signaling plays a critical role in activating M-opsin and repressing S-opsin. Here, we developed an image analysis approach to identify individual cone cells and evaluate their opsin expression from immunofluorescence imaging tiles spanning roughly 6 mm along the D-V axis of the mouse retina. From analyzing the opsin expression of ~250,000 cells, we found that cones make a binary decision between S-opsin only and co-expression competent fates. Co-expression competent cells express graded levels of S- and M-opsins, depending nonlinearly on their position in the dorsal-ventral axis. M- and S-opsin expression display differential, inverse patterns. Using these single-cell data, we developed a quantitative, probabilistic model of cone cell decisions in the retinal tissue based on thyroid hormone signaling activity. The model recovers the probability distribution for cone fate patterning in the mouse retina and describes a minimal set of interactions that are necessary to reproduce the observed cell fates. Our study provides a paradigm describing how differential responses to regulatory inputs generate complex patterns of binary and graded cell fates. The development of a cell in a mammalian tissue is governed by a complex regulatory network that responds to many input signals to give the cell a distinct identity, a process referred to as cell-fate specification. Some of these cell fates have binary on-or-off gene expression patterns, while others have graded gene expression that changes across the tissue. Differentiation of the photoreceptor cells that sense light in the mouse retina provides a good example of this process. Here, we explore how complex patterns of cell fates are specified in the mouse retina by building a computational model based on analysis of a large number of photoreceptor cells from microscopy images of whole retinas. We use the data and the model to study what exactly it means for a cell to have a binary or graded cell fate and how these cell fates can be distinguished from each other. Our study shows how tens-of-thousands of individual photoreceptor cells can be patterned across a complex tissue by a regulatory network, creating a different outcome depending upon the received inputs.
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Affiliation(s)
- Kiara C. Eldred
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Cameron Avelis
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Robert J. Johnston
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (RJJ); (ER)
| | - Elijah Roberts
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (RJJ); (ER)
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12
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The topography of rods, cones and intrinsically photosensitive retinal ganglion cells in the retinas of a nocturnal (Micaelamys namaquensis) and a diurnal (Rhabdomys pumilio) rodent. PLoS One 2018; 13:e0202106. [PMID: 30092025 PMCID: PMC6084985 DOI: 10.1371/journal.pone.0202106] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 07/28/2018] [Indexed: 11/19/2022] Open
Abstract
We used immunocytochemistry to determine the presence and topographical density distributions of rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) in the four-striped field mouse (Rhabdomys pumilio) and the Namaqua rock mouse (Micaelamys namaquensis). Both species possessed duplex retinas that were rod dominated. In R. pumilio, the density of both cones and rods were high (cone to rod ratio: 1:1.23) and reflected the species' fundamentally diurnal, but largely crepuscular lifestyle. Similarly, the ratio of cones to rods in M. namaquensis (1:12.4) reflected its nocturnal lifestyle. Similar rod density peaks were observed (R. pumilio: ~84467/mm2; M. namaquensis: ~81088/mm2), but a density gradient yielded higher values in the central (~56618/mm2) rather than in the peripheral retinal region (~32689/mm2) in R. pumilio. Two separate cone types (S-cones and M/L-cones) were identified implying dichromatic color vision in the study species. In M. namaquensis, both cone populations showed a centro-peripheral density gradient and a consistent S- to M/L-cone ratio (~1:7.8). In R. pumilio, S cones showed a centro-peripheral gradient (S- to M/L-cone ratio; central: 1:7.8; peripheral: 1:6.8) which appeared to form a visual streak, and a specialized area of M/L-cones (S- to M/L-cone ratio: 1:15) was observed inferior to the optic nerve. The number of photoreceptors per linear degree of visual angle, estimated from peak photoreceptor densities and eye size, were four cones and 15 rods per degree in M. namaquensis and 11 cones and 12 rods per degree in R. pumilio. Thus, in nocturnal M. namaquensis rods provide much finer image sampling than cones, whereas in diurnal/crepuscular R. pumilio both photoreceptor types provide fine image sampling. IpRGCs were comparably sparse in R. pumilio (total = 1012) and M. namaquensis (total = 862), but were homogeneously distributed in M. namaquensis and densest in the dorso-nasal quadrant in R. pumilio. The adaptive significance of the latter needs further investigation.
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Variation in opsin transcript expression explains intraretinal differences in spectral sensitivity of the northern anchovy. Vis Neurosci 2018; 35:E005. [DOI: 10.1017/s0952523818000019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractVertebrate retinal photoreceptors house visual pigments that absorb light to begin the process of vision. The light absorbed by a visual pigment depends on its two molecular components: protein (opsin) and chromophore (a vitamin A derivative). Although an increasing number of studies show intraretinal variability in visual pigment content, it is only for two mammals (human and mouse) and two birds (chicken and pigeon) that such variability has been demonstrated to underlie differences in spectral sensitivity of the animal. Here, we show that the spectral sensitivity of the northern anchovy varies with retinal quadrant and that this variability can be explained by differences in the expression of opsin transcripts. Retinal (vitamin A1) was the only chromophore detected in the retina, ruling out this molecular component as a source of variation in spectral sensitivity. Chromatic adaptation experiments further showed that the dorsal retina had the capacity to mediate color vision. Together with published results for the ventral retina, this study is the first to demonstrate that intraretinal opsin variability in a fish drives corresponding variation in the animal’s spectral sensitivity.
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Zukoshi R, Savelli I, Novales Flamarique I. Foraging performance of two fishes, the threespine stickleback and the Cumaná guppy, under different light backgrounds. Vision Res 2018; 145:31-38. [DOI: 10.1016/j.visres.2018.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 03/24/2018] [Accepted: 03/26/2018] [Indexed: 10/16/2022]
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15
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Zhao X, Wong KY, Zhang DQ. Mapping physiological inputs from multiple photoreceptor systems to dopaminergic amacrine cells in the mouse retina. Sci Rep 2017; 7:7920. [PMID: 28801634 PMCID: PMC5554153 DOI: 10.1038/s41598-017-08172-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/07/2017] [Indexed: 01/28/2023] Open
Abstract
In the vertebrate retina, dopamine is synthesized and released by a specialized type of amacrine cell, the dopaminergic amacrine cell (DAC). DAC activity is stimulated by rods, cones, and melanopsin-expressing intrinsically photosensitive retinal ganglion cells upon illumination. However, the relative contributions of these three photoreceptor systems to the DAC light-induced response are unknown. Here we found that rods excite dark-adapted DACs across a wide range of stimulation intensities, primarily through connexin-36-dependent rod pathways. Similar rod-driven responses were observed in both ventral and dorsal DACs. We further found that in the dorsal retina, M-cones and melanopsin contribute to dark-adapted DAC responses with a similar threshold intensity. In the ventral retina, however, the threshold intensity for M-cone-driven responses was two log units greater than that observed in dorsal DACs, and melanopsin-driven responses were almost undetectable. We also examined the DAC response to prolonged adapting light and found such responses to be mediated by rods under dim lighting conditions, rods/M-cones/melanopsin under intermediate lighting conditions, and cones and melanopsin under bright lighting conditions. Our results elucidate the relative contributions of the three photoreceptor systems to DACs under different lighting conditions, furthering our understanding of the role these cells play in the visual system.
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Affiliation(s)
- Xiwu Zhao
- Eye Research Institute, Oakland University, Rochester, MI, United States.,Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Kwoon Y Wong
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States.,Department of Molecular, Cellular & Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Dao-Qi Zhang
- Eye Research Institute, Oakland University, Rochester, MI, United States.
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Rhim I, Coello-Reyes G, Ko HK, Nauhaus I. Maps of cone opsin input to mouse V1 and higher visual areas. J Neurophysiol 2017; 117:1674-1682. [PMID: 28100658 DOI: 10.1152/jn.00849.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/18/2016] [Accepted: 01/18/2017] [Indexed: 11/22/2022] Open
Abstract
Studies in the mouse retina have characterized the spatial distribution of an anisotropic ganglion cell and photoreceptor mosaic, which provides a solid foundation to study how the cortex pools from afferent parallel color channels. In particular, the mouse's retinal mosaic exhibits a gradient of wavelength sensitivity along its dorsoventral axis. Cones at the ventral extreme mainly express S opsin, which is sensitive to ultraviolet (UV) wavelengths. Then, moving toward the retina's dorsal extreme, there is a transition to M-opsin dominance. Here, we tested the hypothesis that the retina's opsin gradient is recapitulated in cortical visual areas as a functional map of wavelength sensitivity. We first identified visual areas in each mouse by mapping retinotopy with intrinsic signal imaging (ISI). Next, we measured ISI responses to stimuli along different directions of the S- and M-color plane to quantify the magnitude of S and M input to each location of the retinotopic maps in five visual cortical areas (V1, AL, LM, PM, and RL). The results illustrate a significant change in the S:M-opsin input ratio along the axis of vertical retinotopy that is consistent with the gradient along the dorsoventral axis of the retina. In particular, V1 populations encoding the upper visual field responded to S-opsin contrast with 6.1-fold greater amplitude than to M-opsin contrast. V1 neurons encoding lower fields responded with 4.6-fold greater amplitude to M- than S-opsin contrast. The maps in V1 and higher visual areas (HVAs) underscore the significance of a wavelength sensitivity gradient for guiding the mouse's behavior.NEW & NOTEWORTHY Two elements of this study are particularly novel. For one, it is the first to quantify cone inputs to mouse visual cortex; we have measured cone input in five visual areas. Next, it is the first study to identify a feature map in the mouse visual cortex that is based on well-characterized anisotropy of cones in the retina; we have identified maps of opsin selectivity in five visual areas.
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Affiliation(s)
- Issac Rhim
- Center for Perceptual Systems, University of Texas, Austin, Texas.,Department of Psychology, University of Texas, Austin, Texas; and
| | - Gabriela Coello-Reyes
- Center for Perceptual Systems, University of Texas, Austin, Texas.,Department of Psychology, University of Texas, Austin, Texas; and.,Department of Neuroscience, University of Texas, Austin, Texas
| | - Hee-Kyoung Ko
- Center for Perceptual Systems, University of Texas, Austin, Texas.,Department of Psychology, University of Texas, Austin, Texas; and.,Department of Neuroscience, University of Texas, Austin, Texas
| | - Ian Nauhaus
- Center for Perceptual Systems, University of Texas, Austin, Texas; .,Department of Psychology, University of Texas, Austin, Texas; and.,Department of Neuroscience, University of Texas, Austin, Texas
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17
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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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18
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Abstract
ABSTRACT
Ultraviolet (UV) light occupies the spectral range of wavelengths slightly shorter than those visible to humans. Because of its shorter wavelength, it is more energetic (and potentially more photodamaging) than ‘visible light’, and it is scattered more efficiently in air and water. Until 1990, only a few animals were recognized as being sensitive to UV light, but we now know that a great diversity, possibly even the majority, of animal species can visually detect and respond to it. Here, we discuss the history of research on biological UV photosensitivity and review current major research trends in this field. Some animals use their UV photoreceptors to control simple, innate behaviors, but most incorporate their UV receptors into their general sense of vision. They not only detect UV light but recognize it as a separate color in light fields, on natural objects or living organisms, or in signals displayed by conspecifics. UV visual pigments are based on opsins, the same family of proteins that are used to detect light in conventional photoreceptors. Despite some interesting exceptions, most animal species have a single photoreceptor class devoted to the UV. The roles of UV in vision are manifold, from guiding navigation and orientation behavior, to detecting food and potential predators, to supporting high-level tasks such as mate assessment and intraspecific communication. Our current understanding of UV vision is restricted almost entirely to two phyla: arthropods and chordates (specifically, vertebrates), so there is much comparative work to be done.
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Affiliation(s)
- Thomas W. Cronin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Michael J. Bok
- Lund University, Department of Biology, Sölvegatan 35, Lund 223 62, Sweden
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19
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Abstract
The mouse has become an important model for understanding the neural basis of visual perception. Although it has long been known that mouse lens transmits ultraviolet (UV) light and mouse opsins have absorption in the UV band, little is known about how UV visual information is processed in the mouse brain. Using a custom UV stimulation system and in vivo calcium imaging, we characterized the feature selectivity of layer 2/3 neurons in mouse primary visual cortex (V1). In adult mice, a comparable percentage of the neuronal population responds to UV and visible stimuli, with similar pattern selectivity and receptive field properties. In young mice, the orientation selectivity for UV stimuli increased steadily during development, but not direction selectivity. Our results suggest that, by expanding the spectral window through which the mouse can acquire visual information, UV sensitivity provides an important component for mouse vision.
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20
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Vlasits AL, Bos R, Morrie RD, Fortuny C, Flannery JG, Feller MB, Rivlin-Etzion M. Visual stimulation switches the polarity of excitatory input to starburst amacrine cells. Neuron 2014; 83:1172-84. [PMID: 25155960 PMCID: PMC4161675 DOI: 10.1016/j.neuron.2014.07.037] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2014] [Indexed: 11/22/2022]
Abstract
Direction-selective ganglion cells (DSGCs) are tuned to motion in one direction. Starburst amacrine cells (SACs) are thought to mediate this direction selectivity through precise anatomical wiring to DSGCs. Nevertheless, we previously found that visual adaptation can reverse DSGCs's directional tuning, overcoming the circuit anatomy. Here we explore the role of SACs in the generation and adaptation of direction selectivity. First, using pharmacogenetics and two-photon calcium imaging, we validate that SACs are necessary for direction selectivity. Next, we demonstrate that exposure to an adaptive stimulus dramatically alters SACs' synaptic inputs. Specifically, after visual adaptation, On-SACs lose their excitatory input during light onset but gain an excitatory input during light offset. Our data suggest that visual stimulation alters the interactions between rod- and cone-mediated inputs that converge on the terminals of On-cone BCs. These results demonstrate how the sensory environment can modify computations performed by anatomically defined neuronal circuits.
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Affiliation(s)
- Anna L Vlasits
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Rémi Bos
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ryan D Morrie
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Cécile Fortuny
- Vision Science Graduate Program, University of California, Berkeley, Berkeley, CA 94720, USA
| | - John G Flannery
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Vision Science Graduate Program, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Marla B Feller
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Michal Rivlin-Etzion
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, 76100, Israel.
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21
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Baden T, Schubert T, Chang L, Wei T, Zaichuk M, Wissinger B, Euler T. A Tale of Two Retinal Domains: Near-Optimal Sampling of Achromatic Contrasts in Natural Scenes through Asymmetric Photoreceptor Distribution. Neuron 2013; 80:1206-17. [DOI: 10.1016/j.neuron.2013.09.030] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2013] [Indexed: 01/10/2023]
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22
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Abstract
AbstractS cones expressing the short wavelength-sensitive type 1 (SWS1) class of visual pigment generally form only a minority type of cone photoreceptor within the vertebrate duplex retina. Hence, their primary role is in color vision, not in high acuity vision. In mammals, S cones may be present as a constant fraction of the cones across the retina, may be restricted to certain regions of the retina or may form a gradient across the retina, and in some species, there is coexpression of SWS1 and the long wavelength-sensitive (LWS) class of pigment in many cones. During retinal development, SWS1 opsin expression generally precedes that of LWS opsin, and evidence from genetic studies indicates that the S cone pathway may be the default pathway for cone development. With the notable exception of the cartilaginous fishes, where S cones appear to be absent, they are present in representative species from all other vertebrate classes. S cone loss is not, however, uncommon; they are absent from most aquatic mammals and from some but not all nocturnal terrestrial species. The peak spectral sensitivity of S cones depends on the spectral characteristics of the pigment present. Evidence from the study of agnathans and teleost fishes indicates that the ancestral vertebrate SWS1 pigment was ultraviolet (UV) sensitive with a peak around 360 nm, but this has shifted into the violet region of the spectrum (>380 nm) on many separate occasions during vertebrate evolution. In all cases, the shift was generated by just one or a few replacements in tuning-relevant residues. Only in the avian lineage has tuning moved in the opposite direction, with the reinvention of UV-sensitive pigments.
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23
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Guimarães-Souza EM, Calaza KC. Selective activation of group III metabotropic glutamate receptor subtypes produces different patterns of γ-aminobutyric acid immunoreactivity and glutamate release in the retina. J Neurosci Res 2012; 90:2349-61. [PMID: 22987212 DOI: 10.1002/jnr.23123] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/10/2012] [Accepted: 07/16/2012] [Indexed: 11/06/2022]
Affiliation(s)
- E M Guimarães-Souza
- Neurobiology of the Retina Laboratory, Neuroscience Program and Departament of Neurobiology, Biology Institute, Federal Fluminense University, Rio de Janeiro, Brazil
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24
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Kawakami K, Xiao B, Ohno RI, Ferdaus MZ, Tongu M, Yamada K, Yamada T, Nomura M, Kobayashi Y, Nabika T. Color Preferences of Laboratory Mice for Bedding Materials: Evaluation Using Radiotelemetry. Exp Anim 2012; 61:109-17. [DOI: 10.1538/expanim.61.109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Kohei Kawakami
- Department of Experimental Animals, Center for Integrated Research in Science, Shimane University
| | - Bing Xiao
- Department of Functional Pathology, Faculty of Medicine, Shimane University
| | - Rei-ichiro Ohno
- Department of Experimental Animals, Center for Integrated Research in Science, Shimane University
| | | | - Miki Tongu
- Department of Experimental Animals, Center for Integrated Research in Science, Shimane University
| | - Kazuo Yamada
- Department of Biochemistry, Faculty of Medicine, Shimane University
| | - Takaya Yamada
- Department of Experimental Animals, Center for Integrated Research in Science, Shimane University
| | - Masato Nomura
- Department of Biotechnology and Chemistry, Faculty of Engineering, Kinki University
| | - Yuta Kobayashi
- Department of Experimental Animals, Center for Integrated Research in Science, Shimane University
| | - Toru Nabika
- Department of Functional Pathology, Faculty of Medicine, Shimane University
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25
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Huberman AD, Niell CM. What can mice tell us about how vision works? Trends Neurosci 2011; 34:464-73. [PMID: 21840069 DOI: 10.1016/j.tins.2011.07.002] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 06/28/2011] [Accepted: 07/05/2011] [Indexed: 11/15/2022]
Abstract
Understanding the neural basis of visual perception is a long-standing fundamental goal of neuroscience. Historically, most vision studies were carried out on humans, macaques and cats. Over the past 5 years, however, a growing number of researchers have begun using mice to parse the mechanisms underlying visual processing; the rationale is that, despite having relatively poor acuity, mice are unmatched in terms of the variety and sophistication of tools available to label, monitor and manipulate specific cell types and circuits. In this review, we discuss recent advances in understanding the mouse visual system at the anatomical, receptive field and perceptual level, focusing on the opportunities and constraints those features provide toward the goal of understanding how vision works.
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Affiliation(s)
- Andrew D Huberman
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA.
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26
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Spectral and temporal sensitivity of cone-mediated responses in mouse retinal ganglion cells. J Neurosci 2011; 31:7670-81. [PMID: 21613480 DOI: 10.1523/jneurosci.0629-11.2011] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The retina uses two photoreceptor types to encode the wide range of light intensities in the natural environment. Rods mediate vision in dim light, whereas cones mediate vision in bright light. Mouse photoreceptors include only 3% cones, and the majority of these coexpress two opsins (short- and middle-wavelength sensitive, S and M), with peak sensitivity to either ultraviolet (360 nm) or green light (508 nm). The M/S-opsin ratio varies across the retina but has not been characterized functionally, preventing quantitative study of cone-mediated vision. Furthermore, physiological and behavioral measurements suggested that mouse retina supports relatively slow temporal processing (peak sensitivity, ∼ 2-5 Hz) compared to primates; however, past studies used visible wavelengths that are inefficient at stimulating mouse S-opsin. Here, we measured the M/S-opsin expression ratio across the mouse retina, as reflected by ganglion cell responses in vitro, and probed cone-mediated ganglion cell temporal properties using ultraviolet light stimulation and linear systems analysis. From recordings in mice lacking rod function (Gnat1(-/-), Rho(-/-)), we estimate ∼ 70% M-opsin expression in far dorsal retina, dropping to <5% M-opsin expression throughout ventral retina. In mice lacking cone function (Gnat2(cpfl3)), light-adapted rod-mediated responses peaked at ∼ 5-7 Hz. In wild-type mice, cone-mediated responses peaked at ∼ 10 Hz, with substantial responsiveness up to ∼ 30 Hz. Therefore, despite the small percentage of cones, cone-mediated responses in mouse ganglion cells are fast and robust, similar to those in primates. These measurements enable quantitative analysis of cone-mediated responses at all levels of the visual system.
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27
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Hogg C, Neveu M, Stokkan KA, Folkow L, Cottrill P, Douglas R, Hunt DM, Jeffery G. Arctic reindeer extend their visual range into the ultraviolet. J Exp Biol 2011; 214:2014-9. [DOI: 10.1242/jeb.053553] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The Arctic has extreme seasonal changes in light levels and is proportionally UV-rich because of scattering of the shorter wavelengths and their reflection from snow and ice. Here we show that the cornea and lens in Arctic reindeer do not block all UV and that the retina responds electrophysiologically to these wavelengths. Both rod and cone photoreceptors respond to UV at low-intensity stimulation. Retinal RNA extraction and in vitro opsin expression show that the response to UV is not mediated by a specific UV photoreceptor mechanism. Reindeer thus extend their visual range into the short wavelengths characteristic of the winter environment and periods of extended twilight present in spring and autumn. A specific advantage of this short-wavelength vision is the use of potential information caused by differential UV reflections known to occur in both Arctic vegetation and different types of snow. UV is normally highly damaging to the retina, resulting in photoreceptor degeneration. Because such damage appears not to occur in these animals, they may have evolved retinal mechanisms protecting against extreme UV exposure present in the daylight found in the snow-covered late winter environment.
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Affiliation(s)
| | - Magella Neveu
- Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK
| | - Karl-Arne Stokkan
- Department of Arctic and Marine Biology, University of Tromsø, 9037 Tromsø, Norway
| | - Lars Folkow
- Department of Arctic and Marine Biology, University of Tromsø, 9037 Tromsø, Norway
| | - Phillippa Cottrill
- Department of Optometry and Visual Science, City University London, Northampton Square, London EC1V 0HB, UK
| | - Ronald Douglas
- Department of Optometry and Visual Science, City University London, Northampton Square, London EC1V 0HB, UK
| | - David M. Hunt
- Institute of Ophthalmology University College London, 11-43 Bath Street, London EC1V 9EL, UK
- School of Animal Biology and Oceans Institute, University of Western Australia, Crawley, Perth, Western Australia 6009, Australia
| | - Glen Jeffery
- Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK
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Why different regions of the retina have different spectral sensitivities: A review of mechanisms and functional significance of intraretinal variability in spectral sensitivity in vertebrates. Vis Neurosci 2011; 28:281-93. [DOI: 10.1017/s0952523811000113] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractVision is used in nearly all aspects of animal behavior, from prey and predator detection to mate selection and parental care. However, the light environment typically is not uniform in every direction, and visual tasks may be specific to particular parts of an animal’s field of view. These spatial differences may explain the presence of several adaptations in the eyes of vertebrates that alter spectral sensitivity of the eye in different directions. Mechanisms that alter spectral sensitivity across the retina include (but are not limited to) variations in: corneal filters, oil droplets, macula lutea, tapeta, chromophore ratios, photoreceptor classes, and opsin expression. The resultant variations in spectral sensitivity across the retina are referred to as intraretinal variability in spectral sensitivity (IVSS). At first considered an obscure and rare phenomenon, it is becoming clear that IVSS is widespread among all vertebrates, and examples have been found from every major group. This review will describe the mechanisms mediating differences in spectral sensitivity, which are in general well understood, as well as explore the functional significance of intraretinal variability, which for the most part is unclear at best.
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29
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Carmona FD, Glösmann M, Ou J, Jiménez R, Collinson JM. Retinal development and function in a 'blind' mole. Proc Biol Sci 2009; 277:1513-22. [PMID: 20007180 DOI: 10.1098/rspb.2009.1744] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Animals adapted to dark ecotopes may experience selective pressure for retinal reduction. No previous studies have explicitly addressed the molecular basis of retinal development in any fossorial mammal. We studied retinal development and function in the Iberian mole Talpa occidentalis, which was presumed to be blind because of its permanently closed eyes. Prenatal retina development was relatively normal, with specification of all cell types and evidence of dorsoventral regionalization. Severe developmental defects occurred after birth, subsequent to lens abnormalities. 'Blind' Iberian moles had rods, cones and rod nuclear ultrastructure typical of diurnal mammals. DiI staining revealed only contralateral projections through the optic chiasm. Y-maze experiments demonstrated that moles retain a photoavoidance response. Over-representation of melanopsin-positive retinal ganglion cells that mediate photoperiodicity was observed. Hence, molecular pathways of eye development in Iberian moles retain the adaptive function of rod/cone primary vision and photoperiodicity, with no evidence that moles are likely to completely lose their eyes on an evolutionary time scale.
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Affiliation(s)
- F David Carmona
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
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30
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The topography of cone photoreceptors in the retina of a diurnal rodent, the agouti (Dasyprocta aguti). Vis Neurosci 2009; 26:167-75. [PMID: 19250601 DOI: 10.1017/s095252380808098x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The presence, density distribution, and mosaic regularity of cone types were studied in the retina of the diurnal agouti, Dasyprocta aguti. Longwave-sensitive (L-) and shortwave-sensitive (S-) cones were detected by antibodies against the respective cone opsins. L- and S-cones were found to represent around 90 and 10% of the cone population, respectively. There was no evidence for L- and S-opsin coexpression in agouti cones. L-cone densities were highest, up to 14,000/mm2, along a horizontal visual streak located about 2-3 mm dorsal to the optic nerve, and the L-cone distribution showed a dorsoventral asymmetry with higher densities in ventral (about 10,000/mm2) than in dorsal (about 4000/mm2) retinal regions. This L-cone topography parallels the agouti's ganglion cell topography. S-cones had a peak density of 1500-2000/mm2 in the central retinal region but did not form a visual streak. Their distribution also showed a dorsoventral asymmetry with densities around 600/mm2 in dorsal and around 1000/mm2 in ventral retinal regions. The patterning of cone arrays was assessed by the density recovery profile analysis. At all eccentricities evaluated, the S-cone mosaic less efficiently packed than the L-cone mosaic. Rod densities ranged from 47,000/mm2 in peripheral to 64,000/mm2 in central retina, and rod:cone ratios were 4:1-9:1. The comparatively low rod density and high cone proportion appear well adapted to the diurnal lifestyle of the agouti.
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32
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Williams GA, Jacobs GH. Cone-based vision in the aging mouse. Vision Res 2007; 47:2037-46. [PMID: 17509638 PMCID: PMC2049007 DOI: 10.1016/j.visres.2007.03.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 03/21/2007] [Accepted: 03/22/2007] [Indexed: 11/27/2022]
Abstract
People often experience age-related declines in cone-based visual capacities despite an absence of apparent visual pathology. Although mice are used as models of human visual pathologies associated with aging, little is known about how age impacts vision in animals with disease-free retinas since most studies have heretofore examined relatively young mice. We examined the effects of age on cone-based vision by assessing opsin gene transcription, cone densities, the flicker electroretinogram (ERG), and behavioral increment thresholds in mice. ERG measurements of cone function showed age-related declines in maximum voltage (Vmax), while opsin gene transcription, cone density, and increment thresholds were unchanged even in extremely old mice. The age-related decline in Vmax seen in mice is qualitatively similar to that documented for human subjects. It is notable that Vmax, a commonly used index of ERG activity, does not predict behavioral performance in the mouse.
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Affiliation(s)
- Gary A Williams
- Neuroscience Research Institute and Department of Psychology, University of California, Santa Barbara, CA 93106, USA.
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33
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Yin L, Smith RG, Sterling P, Brainard DH. Chromatic properties of horizontal and ganglion cell responses follow a dual gradient in cone opsin expression. J Neurosci 2006; 26:12351-61. [PMID: 17122060 PMCID: PMC1815484 DOI: 10.1523/jneurosci.1071-06.2006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In guinea pig retina, immunostaining reveals a dual gradient of opsins: cones expressing opsin sensitive to medium wavelengths (M) predominate in the upper retina, whereas cones expressing opsin sensitive to shorter wavelengths (S) predominate in the lower retina. Whether these gradients correspond to functional gradients in postreceptoral neurons is essentially unknown. Using monochromatic flashes, we measured the relative weights with which M, S, and rod signals contribute to horizontal cell responses. For a background that produced 4.76 log10 photoisomerizations per rod per second (Rh*/rod/s), mean weights in superior retina were 52% (M), 2% (S), and 46% (rod). Mean weights in inferior retina were 9% (M), 50% (S), and 41% (rod). In superior retina, cone opsin weights agreed quantitatively with relative pigment density estimates from immunostaining. In inferior retina, cone opsin weights agreed qualitatively with relative pigment density estimates, but quantitative comparison was impossible because individual cones coexpress both opsins to varying and unquantifiable degrees. We further characterized the functional gradients in horizontal and brisk-transient ganglion cells using flickering stimuli produced by various mixtures of blue and green primary lights. Cone weights for both cell types resembled those obtained for horizontal cells using monochromatic flashes. Because the brisk-transient ganglion cell is thought to mediate behavioral detection of luminance contrast, our results are consistent with the hypothesis that the dual gradient of cone opsins assists achromatic contrast detection against different spectral backgrounds. In our preparation, rod responses did not completely saturate, even at background light levels typical of outdoor sunlight (5.14 log10 Rh*/rod/s).
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Affiliation(s)
- Lu Yin
- Departments of Neuroscience and
| | | | | | - David H. Brainard
- Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Ahnelt PK, Schubert C, Kübber-Heiss A, Schiviz A, Anger E. Independent variation of retinal S and M cone photoreceptor topographies: A survey of four families of mammals. Vis Neurosci 2006; 23:429-35. [PMID: 16961976 DOI: 10.1017/s095252380623342x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 12/26/2005] [Indexed: 11/07/2022]
Abstract
In mammals, cone photoreceptor subtypes are thought to establish topographies that reflect the species-relevant properties of the visual environment. Middle- to long-wavelength-sensitive (M) cones are the dominant population and in most species they form an area centralis at the visual axis. Short-wavelength-sensitive (S) cone topographies do not always match this pattern. We here correlate the interrelationship of S and M cone topographies in representatives of several mammalian orders with different visual ecology, including man, cheetah, cat, Eurasian lynx, African lion, wild hog, roe deer, and red deer. Retinas were labeled with opsin antisera and S and M cone distributions as well as S/M cone ratios were mapped. We find that species inhabiting open environments show M cone horizontal streaks (cheetah, pig, deer). Species living in structured habitats (tiger, lynx, red deer) have increased S cone densities along the retinal margin. In species with active vision (cheetah, bear, tiger, man), S cone distributions are more likely to follow the centripetal M cone gradients. Small species show a ventral bias of peak S cone density which either matches the peak of M cone density in a temporal area centralis (diurnal sciurid rodents, tree shrews) or not (cat, manul, roe deer). Thus, in addition to habitat structure, physical size and specific lifestyle patterns (e.g. food acquisition) appear to underlie the independent variations of M and S cone topographies.
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Affiliation(s)
- Peter Kurt Ahnelt
- Department of Physiology, Unit of Physiology and Pathophysiology, Medical University of Vienna, Vienna, Austria.
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Nikonov SS, Kholodenko R, Lem J, Pugh EN. Physiological features of the S- and M-cone photoreceptors of wild-type mice from single-cell recordings. ACTA ACUST UNITED AC 2006; 127:359-74. [PMID: 16567464 PMCID: PMC2151510 DOI: 10.1085/jgp.200609490] [Citation(s) in RCA: 224] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cone cells constitute only 3% of the photoreceptors of the wild-type (WT) mouse. While mouse rods have been thoroughly investigated with suction pipette recordings of their outer segment membrane currents, to date no recordings from WT cones have been published, likely because of the rarity of cones and the fragility of their outer segments. Recently, we characterized the photoreceptors of Nrl−/− mice, using suction pipette recordings from their “inner segments” (perinuclear region), and found them to be cones. Here we report the use of this same method to record for the first time the responses of single cones of WT mice, and of mice lacking the α-subunit of the G-protein transducin (Gtα−/−), a loss that renders them functionally rodless. Most cones were found to functionally co-express both S- (λmax = 360 nm) and M- (λmax = 508 nm) cone opsins and to be maximally sensitive at 360 nm (“S-cones”); nonetheless, all cones from the dorsal retina were found to be maximally sensitive at 508 nm (“M-cones”). The dim-flash response kinetics and absolute sensitivity of S- and M-cones were very similar and not dependent on which of the coexpressed cone opsins drove transduction; the time to peak of the dim-flash response was ∼70 ms, and ∼0.2% of the circulating current was suppressed per photoisomerization. Amplification in WT cones (A ∼4 s−2) was found to be about twofold lower than in rods (A ∼8 s−2). Mouse M-cones maintained their circulating current at very nearly the dark adapted level even when >90% of their M-opsin was bleached. S-cones were less tolerant to bleached S-opsin than M-cones to bleached M-opsin, but still far more tolerant than mouse rods to bleached rhodopsin, which exhibit persistent suppression of nearly 50% of their circulating current following a 20% bleach. Thus, the three types of mouse opsin appear distinctive in the degree to which their bleached, unregenerated opsins generate “dark light.”
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Affiliation(s)
- Sergei S Nikonov
- FM Kirby Center for Molecular Ophthalmology, Department of Ophthalmology, School of Medicine, University of Pennsylvania, Philadelphia, 19104, USA
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36
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Pinto LH, Vitaterna MH, Siepka SM, Shimomura K, Lumayag S, Baker M, Fenner D, Mullins RF, Sheffield VC, Stone EM, Heffron E, Takahashi JS. Results from screening over 9000 mutation-bearing mice for defects in the electroretinogram and appearance of the fundus. Vision Res 2005; 44:3335-45. [PMID: 15536001 PMCID: PMC3756145 DOI: 10.1016/j.visres.2004.07.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2004] [Revised: 07/14/2004] [Indexed: 10/26/2022]
Abstract
Random mutagenesis combined with phenotypic screening using carefully crafted functional tests has successfully led to the discovery of genes that are essential for a number of functions. This approach does not require prior knowledge of the identity of the genes that are involved and is a way to ascribe function to the nearly 6000 genes for which knowledge of the DNA sequence has been inadequate to determine the function of the gene product. In an effort to identify genes involved in the visual system via this approach, we have tested over 9000 first and third generation offspring of mice treated with the mutagen N-ethyl-N-nitrosourea (ENU) for visual defects, as evidenced by abnormalities in the electroretinogram and appearance of the fundus. We identified 61 putative mutations with this procedure and outline the steps needed to identify the affected genes.
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Affiliation(s)
- Lawrence H Pinto
- Department of Neurobiology and Physiology and Center for Functional Genomics, Northwestern University, 2205 Tech Drive, Hogan Hall 2-140, Evanston, IL 60208, USA.
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Jacobs GH, Williams GA, Fenwick JA. Influence of cone pigment coexpression on spectral sensitivity and color vision in the mouse. Vision Res 2004; 44:1615-22. [PMID: 15135998 DOI: 10.1016/j.visres.2004.01.016] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 01/26/2004] [Indexed: 11/30/2022]
Abstract
The mouse retina contains both middle-wavelength-sensitive (M) and ultraviolet-sensitive (UV) photopigments that are coexpressed in cones. To examine some potential visual consequences of cone pigment coexpression, spectral sensitivity functions were measured in mice (Mus musculus) using both the flicker electroretinogram (ERG) and behavioral discrimination tests. Discrimination tests were also employed to search for the presence of color vision in the mouse. Spectral sensitivity functions for the mouse obtained from ERG measurements and from psychophysical tests each reveal contributions from two classes of cone having peak sensitivities (lambda(max)) of approximately 360 and 509-512 nm. The relative contributions of the two pigment types to spectral sensitivity differ significantly in the two types of measurements with a relationship reversed from that often seen in mammals. Mice were capable of discriminating between some pairs of spectral stimuli under test conditions where luminance-related cues were irrelevant. Since mice can make dichromatic color discriminations, their visual systems must be able to exploit differences in the spectral absorption properties among the cones. Complete selective segregation of opsins into individual photoreceptors is apparently not a prerequisite for color vision.
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Affiliation(s)
- Gerald H Jacobs
- Neuroscience Research Institute and Department of Psychology, University of California, Santa Barbara, CA 93106-5060, USA.
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Latham N, Mason G. From house mouse to mouse house: the behavioural biology of free-living Mus musculus and its implications in the laboratory. Appl Anim Behav Sci 2004. [DOI: 10.1016/j.applanim.2004.02.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Peichl L, Nemec P, Burda H. Unusual cone and rod properties in subterranean African mole-rats (Rodentia, Bathyergidae). Eur J Neurosci 2004; 19:1545-58. [PMID: 15066151 DOI: 10.1111/j.1460-9568.2004.03263.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have determined the presence of spectral cone types, and the population densities of cones and rods, in subterranean mole-rats of the rodent family Bathyergidae, for which light and vision seems of little importance. Most mammals have two spectral cone types, a majority of middle- to long-wave-sensitive (L-) cones, and a minority of short-wave-sensitive (S-)cones. We were interested to see whether the subterranean bathyergids show the same pattern. In three species, Ansell's mole-rat Cryptomys anselli, the giant mole-rat Cryptomys mechowi and the naked mole-rat Heterocephalus glaber, spectral cone types and rods were assessed immunocytochemically with opsin-specific antibodies. All three species had rod-dominated retinae but possessed significant cone populations. A quantitative assessment in C. anselli and C. mechowi revealed surprisingly low photoreceptor densities of 100 000-150 000/mm(2), and high cone proportions, approximately 10% (8000-15 000/mm(2)). In all three species, the vast majority of the cones were strongly S-opsin-immunoreactive; L-opsin immunoreactivity was much fainter. In C. anselli, approximately 20% of the cones showed exclusive S-opsin label, approximately 10% exclusive L-opsin label and approximately 70% strong S-opsin and faint L-opsin double label (potential dual-pigment cones). This is the first observation in any mammal of an S-opsin dominance and low levels of L-opsin across the entire retina. It contrasts starkly with the situation in the muroid blind mole-rat Spalax ehrenbergi, which has been reported to possess L-opsin but no S-opsin. Evidently, within rodents an adaptation to subterranean life is compatible with very different spectral cone properties.
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Affiliation(s)
- Leo Peichl
- Max Planck Institute for Brain Research, Deutschordenstr. 46, D-60528 Frankfurt a. M., Germany.
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41
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Understanding behaviour: the relevance of ethological approaches in laboratory animal science. Appl Anim Behav Sci 2003. [DOI: 10.1016/s0168-1591(02)00285-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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42
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Abstract
A microelectrode was used to detect local visually evoked potentials from clusters of neurons in the murine superior colliculus. Chromatic stimuli and selective chromatic adaptation were used to identify responses of UV and middle-wavelength-sensitive (M) cones and/or rods. Three types of evoked potentials were found: those driven by UV and M cones and/or rods and those driven only by UV cone or only by M cones and/or rods. UV cone responses were more frequent in the medial and those from M cones more common in the lateral part of the superior colliculus. All three responses were found in the same area. UV cones provide a significant input to the murine superior colliculus. The spatial distribution of these responses in the superior colliculus reflects the organization of UV cones in the retina. Although synergistic inputs from UV- and M-cone and/or rod inputs appear to mix in local evoked responses in the superior colliculus, some areas are found to transmit only UV- or only M-cone and/or rod responses, indicating that there cannot be a widespread mixing of UV- and M-cone opsins in all murine cones.
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Affiliation(s)
- B Ekesten
- Unit for Ophthalmology, Swedish University of Agricultural Sciences, P.O. Box 7018, Uppsala, Sweden.
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Brainard GC, Hanifin JP, Barker FM, Sanford B, Stetson MH. Influence of near-ultraviolet radiation on reproductive and immunological development in juvenile male Siberian hamsters. J Exp Biol 2001; 204:2535-41. [PMID: 11511669 DOI: 10.1242/jeb.204.14.2535] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The aim of this study was to characterize the lenticular ultraviolet transmission of the Siberian hamster (Phodopus sungorus) and to probe the range of near-ultraviolet (UV-A, 315–400nm) and visible wavelengths (400–760nm) for modulating the photoperiodic regulation of its reproductive and immune systems. Ocular lenses from adult hamsters were found to transmit UV-A wavelengths at similar levels to visible wavelengths, with a short-wavelength cut-off of 300nm. Five separate studies compared the responses of juvenile male hamsters to long photoperiods (16h:8h L:D), short photoperiods (10h:14h L:D) and short photoperiods interrupted by an equal photon pulse of monochromatic light of 320, 340, 360, 500 or 725nm during the night. The results show that UV-A wavelengths at 320, 340 and 360nm can regulate both reproductive and immune short-photoperiod responses as effectively as visible monochromatic light at 500nm. In contrast, long-wavelength visible light at 725nm did not block the short-photoperiod responses. These results suggest that both wavelengths in the visible spectrum, together with UV-A wavelengths, contribute to hamster photoperiodism in natural habitats.
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Affiliation(s)
- G C Brainard
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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Linberg K, Cuenca N, Ahnelt P, Fisher S, Kolb H. Comparative anatomy of major retinal pathways in the eyes of nocturnal and diurnal mammals. PROGRESS IN BRAIN RESEARCH 2001; 131:27-52. [PMID: 11420947 DOI: 10.1016/s0079-6123(01)31006-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- K Linberg
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
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Abstract
PURPOSE To define the physiological and structural changes that may accompany aging in the normal mouse retina. METHODS C57BL/6 mice were maintained under cyclic light for either 2, 6, or 12 months. After rod- and cone-mediated corneal electroretinograms (ERG's) were recorded from anesthetized animals, the retinal structure was quantitatively examined. Photoreceptor cell density was measured within 100-microm regions of the central superior and inferior retina. Cone photoreceptor subtypes were identified by immunocytochemistry. RESULTS The amplitudes of rod- and cone-mediated ERG's were reduced in older mice, although the overall ERG wave-form did not change appreciably and implicit times were not changed in an age-dependent fashion. In comparison, there was no significant age-related decline in rod or cone photoreceptor density. CONCLUSIONS The amplitude of the mouse ERG declines with age. This change does not appear to reflect a change in the structural integrity of the photoreceptor cells. In functional studies of murine models of late-onset retinal disorders, it will be important to take these changes into consideration.
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Affiliation(s)
- C Li
- Department of Biological Sciences, University of Illinois at Chicago, USA
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Lowrey PL, Takahashi JS. Genetics of the mammalian circadian system: Photic entrainment, circadian pacemaker mechanisms, and posttranslational regulation. Annu Rev Genet 2001; 34:533-562. [PMID: 11092838 DOI: 10.1146/annurev.genet.34.1.533] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During the past four years, significant progress has been made in identifying the molecular components of the mammalian circadian clock system. An autoregulatory transcriptional feedback loop similar to that described in Drosophila appears to form the core circadian rhythm generating mechanism in mammals. Two basic helix-loop-helix (bHLH) PAS (PER-ARNT-SIM) transcription factors, CLOCK and BMAL1, form the positive elements of the system and drive transcription of three Period and two Cryptochrome genes. The protein products of these genes are components of a negative feedback complex that inhibits CLOCK and BMAL1 to close the circadian loop. In this review, we focus on three aspects of the circadian story in mammals: the genetics of the photic entrainment pathway; the molecular components of the circadian pacemaker in the hypothalamic suprachiasmatic nucleus; and the role of posttranslational regulation of circadian elements. A molecular description of the mammalian circadian system has revealed that circadian oscillations may be a fundamental property of many cells in the body and that a circadian hierarchy underlies the temporal organization of animals.
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Affiliation(s)
- P L Lowrey
- Howard Hughes Medical Institute, Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA.
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Abstract
Unlike in birds and cold-blooded vertebrates' retinas, the photoreceptors of mammalian retinas were long supposed to be morphologically uniform and difficult to distinguish into subtypes. A number of new techniques have now begun to overcome the previous limitations. A hitherto unexpected variability of spectral and morphological subtypes and topographic patterns of distribution in the various retinas are being revealed. We begin to understand the design of the photoreceptor mosaics, the constraints of evolutionary history and the ecological specialization of these mosaics in all the mammalian subgroups. The review discusses current cytological identification of mammalian photoreceptor types and speculates on the likely "bottleneck-scenario" for the origin of the basic design of the mammalian retina. It then provides a brief synopsis of current data on the photoreceptors in the various mammalian orders and derives some trends for phenomena such as rod/cone dualism, spectral range, preservation or loss of double cones and oil droplets, photopigment co-expression and mono- and tri-chromacy. Finally, we attempt to demonstrate that, building on the limits of an ancient rod dominant (probably dichromatic) model, mammalian retinas have developed considerable radiation. Comparing the nonprimate models with the intensively studied primate model should provide us with a deeper understanding of the basic design of the mammalian retina.
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Affiliation(s)
- P K Ahnelt
- Institut für Physiologie, Medizinische Fakultät, Universität Wien, Wien, Austria.
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Abstract
Responses of single retinal ganglion cells in different areas of mouse retina were studied to determine their cone inputs, using spectral sensitivity functions and chromatic adaptation. Spectral sensitivity curves were based on threshold response criteria to full field stimulation. The retina of the mouse was viewed through a dilated pupil with a surgical microscope. Ganglion cells were classified into three groups: one receiving inputs from short wave sensitive cones, a second receiving inputs from only middle wavelength sensitive cones and a third receiving inputs from both of these types of cones. The ventral retina, contained a large fraction of the first group of ganglion cells. The dorsal retina and the border between these two areas contained relatively more of the latter two groups. A small fraction of cells were found which displayed antagonistic-like interactions between photoreceptor systems. The results demonstrate that single ganglion cells in mouse retina can select responses from only one of the two cone mechanisms present in this retina, even in areas containing both types of cones.
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Affiliation(s)
- B Ekesten
- Unit for Ophthalmology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Mice lacking G-protein receptor kinase 1 have profoundly slowed recovery of cone-driven retinal responses. J Neurosci 2000. [PMID: 10704496 DOI: 10.1523/jneurosci.20-06-02209.2000] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
G-Protein receptor kinase 1 (GRK1) ("rhodopsin kinase") is necessary for the inactivation of photoactivated rhodopsin, the light receptor of the G-protein transduction cascade of rod photoreceptors. GRK1 has also been reported to be present in retinal cones in which its function is unknown. To examine the role of GRK1 in retinal cone signaling pathways, we measured in mice having null mutations of GRK1 (GRK1 -/-) cone-driven electroretinographic (ERG) responses, including an a-wave component identified as the field potential generated by suppression of the circulating current of the cone photoreceptors. Dark-adapted GRK1 -/- animals generated cone-driven ERGs having saturating amplitudes and sensitivities in both visible and UV spectral regions similar to those of wild-type (WT) mice. However, after exposure to a bright conditioning flash, the cone-driven ERGs of GRK1 -/- animals recovered 30-50 times more slowly than those of WT mice and similarly slower than the cone-driven ERGs of mice homozygously null for arrestin (Arrestin -/-), whose cone (but not rod) response recoveries were found to be as rapid as those of WT. Our observations argue that GRK1 is essential for normal deactivation of murine cone phototransduction and provide the first functional evidence for a major role of a specific GRK in the inactivation of vertebrate cone phototransduction.
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Szél A, Lukáts A, Fekete T, Szepessy Z, Röhlich P. Photoreceptor distribution in the retinas of subprimate mammals. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2000; 17:568-579. [PMID: 10708038 DOI: 10.1364/josaa.17.000568] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Relevant data on the distribution of color cones are summarized, with special emphasis on the marked dorsoventral asymmetries observed in a number of mammalian species. In addition, an overview is given of studies that demonstrate the coexistence of two visual pigments within the same cone cell. The biological significance of these phenomena is discussed in conjunction with comparative immunocytochemical analyses of subprimate retinas. Based on various cone distribution patterns and temporal and spatial visual pigment coexpression, two models of cone photoreceptor differentiation are suggested.
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Affiliation(s)
- A Szél
- Department of Human Morphology, Semmelweis University of Medicine, Budapest, Hungary.
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