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Sekyi MT, Feri M, Desfor S, Atkinson KC, Golestany B, Beltran F, Tiwari-Woodruff SK. Demyelination and neurodegeneration early in experimental autoimmune encephalomyelitis contribute to functional deficits in the anterior visual pathway. Sci Rep 2024; 14:24048. [PMID: 39402114 PMCID: PMC11473523 DOI: 10.1038/s41598-024-73792-z] [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: 05/09/2024] [Accepted: 09/20/2024] [Indexed: 10/17/2024] Open
Abstract
Impaired visual function is a prevalent feature of optic neuritis (ON) in multiple sclerosis (MS). Abnormal visual evoked potential (VEP) findings of increased latencies, reduced amplitudes and abnormal waveforms as well as decreased retinal nerve fiber layer (RNFL) assessed by optical coherence tomography (OCT) are hallmarks of ON-induced visual dysfunction. Here we utilized the experimental autoimmune encephalomyelitis (EAE) mouse model of MS to investigate the functional and pathological progression during early (before any clinical symptoms), peak (initial maximal clinical symptoms), and late (chronic disease for > 3 weeks) disease stages. Demyelination and initial stages of axon damage were observed in early EAE. Significant demyelination, inflammation, increased axon damage and impaired P1/N2 amplitudes and latencies by VEP were seen in middle and late EAE groups. A decrease in RNFL thickness by OCT was observed only during late EAE. NanoString analysis of optic nerves from late EAE indicated elevated inflammation-related genes, reduced myelin-related genes, and changes in axon degeneration-related genes. Early inflammatory demyelination and functional deficits of the visual pathway, if untreated, may lead to severe irrecoverable axon damage in EAE. These studies potentially help explain the progression of visual dysfunction during MS.
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Affiliation(s)
- Maria T Sekyi
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA
| | - Micah Feri
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA
| | - Shane Desfor
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA
| | - Kelley C Atkinson
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA
| | - Batis Golestany
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA
| | - Fernando Beltran
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA
| | - Seema K Tiwari-Woodruff
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Rm 3140, Multidisciplinary Research Building, 900 University Ave, Riverside, CA, 92521, USA.
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2
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MacIsaac AR, Wellington AJ, Filicetti K, Eggers ED. Impaired dopamine signaling in early diabetic retina: Insights from D1R and D4R agonist effects on whole retina responses. Exp Eye Res 2024; 247:110049. [PMID: 39151774 PMCID: PMC11392630 DOI: 10.1016/j.exer.2024.110049] [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: 06/07/2024] [Revised: 07/23/2024] [Accepted: 08/13/2024] [Indexed: 08/19/2024]
Abstract
The retina has low dopamine levels early in diabetes. To determine how low dopamine levels affected dopamine signaling, the effects of dopamine receptor agonists and mRNA localization were measured after 6 weeks of diabetes. Whole retina ex vivo electroretinogram (ERG) recordings were used to analyze how dopamine type 1 receptor (D1R) and type 4 (D4R) agonists change the light-evoked retinal responses of non-diabetic and 6-week diabetic (STZ injected) mouse retinas. Fluorescence in situ hybridization was utilized to analyze D4R and D1R mRNA locations and expression levels. D4R activation reduced A- and B-wave ERG amplitudes and increased B-wave implicit time and rise-time in the non-diabetic group without a corresponding change in the diabetic group. D1R activation increased B-wave rise-time and oscillatory potential peak time in the non-diabetic group also with no change in the diabetic group. The lack of responsivity to D1R or D4R agonists shows an impairment of dopamine signaling in the diabetic retina. D4R mRNA was found primarily in the outer nuclear layer where photoreceptor cell bodies reside. D1R mRNA was found in the inner nuclear layer and ganglion cell layer that contain bipolar, amacrine, horizontal and ganglion cells. There was no change in D4R or D1R mRNA expression between the non-diabetic and diabetic retinas. This suggests that the significant dopamine signaling changes observed were not from lower receptor expression levels but could be due to changes in dopamine receptor activity or protein levels. These studies show that changes in retinal dopamine signaling could be an important mechanism of diabetic retinal dysfunction.
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MESH Headings
- Animals
- Male
- Mice
- Diabetes Mellitus, Experimental/metabolism
- Diabetic Retinopathy/metabolism
- Dopamine/metabolism
- Dopamine Agonists/pharmacology
- Electroretinography
- In Situ Hybridization, Fluorescence
- Mice, Inbred C57BL
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D4/metabolism
- Receptors, Dopamine D4/genetics
- Receptors, Dopamine D4/agonists
- Retina/metabolism
- Retina/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Signal Transduction
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Affiliation(s)
- Angela R MacIsaac
- Department of Physiology, University of Arizona, Tucson, AZ, USA; Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA.
| | - Andrea J Wellington
- Department of Physiology, University of Arizona, Tucson, AZ, USA; Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA.
| | - Kyle Filicetti
- Department of Physiology, University of Arizona, Tucson, AZ, USA; Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA.
| | - Erika D Eggers
- Department of Physiology, University of Arizona, Tucson, AZ, USA; Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA.
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3
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Sanchez-Bretano A, Keeling E, Scott JA, Lynn SA, Soundara-Pandi SP, Macdonald SL, Newall T, Griffiths H, Lotery AJ, Ratnayaka JA, Self JE, Lee H. Human equivalent doses of L-DOPA rescues retinal morphology and visual function in a murine model of albinism. Sci Rep 2023; 13:17173. [PMID: 37821525 PMCID: PMC10567794 DOI: 10.1038/s41598-023-44373-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/07/2023] [Indexed: 10/13/2023] Open
Abstract
L-DOPA is deficient in the developing albino eye, resulting in abnormalities of retinal development and visual impairment. Ongoing retinal development after birth has also been demonstrated in the developing albino eye offering a potential therapeutic window in humans. To study whether human equivalent doses of L-DOPA/Carbidopa administered during the crucial postnatal period of neuroplasticity can rescue visual function, OCA C57BL/6 J-c2J OCA1 mice were treated with a 28-day course of oral L-DOPA/Carbidopa at 3 different doses from 15 to 43 days postnatal age (PNA) and for 3 different lengths of treatment, to identify optimum dosage and treatment length. Visual electrophysiology, acuity, and retinal morphology were measured at 4, 5, 6, 12 and 16 weeks PNA and compared to untreated C57BL/6 J (WT) and OCA1 mice. Quantification of PEDF, βIII-tubulin and syntaxin-3 expression was also performed. Our data showed impaired retinal morphology, decreased retinal function and lower visual acuity in untreated OCA1 mice compared to WT mice. These changes were diminished or eliminated when treated with higher doses of L-DOPA/Carbidopa. Our results demonstrate that oral L-DOPA/Carbidopa supplementation at human equivalent doses during the postnatal critical period of retinal neuroplasticity can rescue visual retinal morphology and retinal function, via PEDF upregulation and modulation of retinal synaptogenesis, providing a further step towards developing an effective treatment for albinism patients.
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Affiliation(s)
- Aida Sanchez-Bretano
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Jennifer A Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Sudha Priya Soundara-Pandi
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Sarah L Macdonald
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Tutte Newall
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Helen Griffiths
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK.
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK.
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4
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Abstract
Although diabetic retinopathy (DR) is clinically diagnosed as a vascular disease, many studies find retinal neuronal and visual dysfunction before the onset of vascular DR. This suggests that DR should be viewed as a neurovascular disease. Prior to the onset of DR, human patients have compromised electroretinograms that indicate a disruption of normal function, particularly in the inner retina. They also exhibit reduced contrast sensitivity. These early changes, especially those due to dysfunction in the inner retina, are also seen in rodent models of diabetes in the early stages of the disease. Rodent models of diabetes exhibit several neuronal mechanisms, such as reduced evoked GABA release, increased excitatory glutamate signaling, and reduced dopamine signaling, that suggest specific neuronal deficits. This suggests that understanding neuronal deficits may lead to early diabetes treatments to ameliorate neuronal dysfunction.
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Affiliation(s)
- Erika D Eggers
- Departments of Physiology and Biomedical Engineering, University of Arizona, Tucson, Arizona, USA;
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5
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Occelli LM, Zobel L, Stoddard J, Wagner J, Pasmanter N, Querubin J, Renner LM, Reynaga R, Winkler PA, Sun K, Marinho LFLP, O'Riordan CR, Frederick A, Lauer A, Tsang SH, Hauswirth WW, McGill TJ, Neuringer M, Michalakis S, Petersen-Jones SM. Development of a translatable gene augmentation therapy for CNGB1-retinitis pigmentosa. Mol Ther 2023; 31:2028-2041. [PMID: 37056049 PMCID: PMC10362398 DOI: 10.1016/j.ymthe.2023.04.005] [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: 01/19/2023] [Revised: 03/07/2023] [Accepted: 04/10/2023] [Indexed: 04/15/2023] Open
Abstract
In this study, we investigate a gene augmentation therapy candidate for the treatment of retinitis pigmentosa (RP) due to cyclic nucleotide-gated channel beta 1 (CNGB1) mutations. We use an adeno-associated virus serotype 5 with transgene under control of a novel short human rhodopsin promoter. The promoter/capsid combination drives efficient expression of a reporter gene (AAV5-RHO-eGFP) exclusively in rod photoreceptors in primate, dog, and mouse following subretinal delivery. The therapeutic vector (AAV5-RHO-CNGB1) delivered to the subretinal space of CNGB1 mutant dogs restores rod-mediated retinal function (electroretinographic responses and vision) for at least 12 months post treatment. Immunohistochemistry shows human CNGB1 is expressed in rod photoreceptors in the treated regions as well as restoration of expression and trafficking of the endogenous alpha subunit of the rod CNG channel required for normal channel formation. The treatment reverses abnormal accumulation of the second messenger, cyclic guanosine monophosphate, which occurs in rod photoreceptors of CNGB1 mutant dogs, confirming formation of a functional CNG channel. In vivo imaging shows long-term preservation of retinal structure. In conclusion, this study establishes the long-term efficacy of subretinal delivery of AAV5-RHO-CNGB1 to rescue the disease phenotype in a canine model of CNGB1-RP, confirming its suitability for future clinical development.
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Affiliation(s)
- Laurence M Occelli
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Lena Zobel
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany; Department of Ophthalmology, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Jonathan Stoddard
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA
| | - Johanna Wagner
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Nathaniel Pasmanter
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Janice Querubin
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Lauren M Renner
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA
| | - Rene Reynaga
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA
| | - Paige A Winkler
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Kelian Sun
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | - Luis Felipe L P Marinho
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA
| | | | - Amy Frederick
- Genomic Medicine Unit, Sanofi, 225 Second Avenue, Waltham, MA 02451, USA
| | - Andreas Lauer
- Casey Eye Institute, Oregon Health & Science University, 515 Campus Drive, Portland, OR 97239, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Columbia Stem Cell Initiative, Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - William W Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Box 100284 HSC, Gainesville, FL 32610, USA
| | - Trevor J McGill
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA; Casey Eye Institute, Oregon Health & Science University, 515 Campus Drive, Portland, OR 97239, USA
| | - Martha Neuringer
- Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185(th) Avenue, Beaverton, OR 97005, USA; Casey Eye Institute, Oregon Health & Science University, 515 Campus Drive, Portland, OR 97239, USA
| | - Stylianos Michalakis
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany; Department of Ophthalmology, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Simon M Petersen-Jones
- College of Veterinary Medicine, Michigan State University, 736 Wilson Road, East Lansing, MI 48864, USA.
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6
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Bhatt Y, Hunt DM, Carvalho LS. The origins of the full-field flash electroretinogram b-wave. Front Mol Neurosci 2023; 16:1153934. [PMID: 37465364 PMCID: PMC10351385 DOI: 10.3389/fnmol.2023.1153934] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 06/12/2023] [Indexed: 07/20/2023] Open
Abstract
The electroretinogram (ERG) measures the electrical activity of retinal neurons and glial cells in response to a light stimulus. Amongst other techniques, clinicians utilize the ERG to diagnose various eye diseases, including inherited conditions such as cone-rod dystrophy, rod-cone dystrophy, retinitis pigmentosa and Usher syndrome, and to assess overall retinal health. An ERG measures the scotopic and photopic systems separately and mainly consists of an a-wave and a b-wave. The other major components of the dark-adapted ERG response include the oscillatory potentials, c-wave, and d-wave. The dark-adapted a-wave is the initial corneal negative wave that arises from the outer segments of the rod and cone photoreceptors hyperpolarizing in response to a light stimulus. This is followed by the slower, positive, and prolonged b-wave, whose origins remain elusive. Despite a large body of work, there remains controversy around the mechanisms involved in the generation of the b-wave. Several hypotheses attribute the origins of the b-wave to bipolar or Müller glial cells or a dual contribution from both cell types. This review will discuss the current hypothesis for the cellular origins of the dark-adapted ERG, with a focus on the b-wave.
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Affiliation(s)
- Yashvi Bhatt
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA, Australia
- Lions Eye Institute Ltd., Nedlands, WA, Australia
| | - David M. Hunt
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA, Australia
- Lions Eye Institute Ltd., Nedlands, WA, Australia
| | - Livia S. Carvalho
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA, Australia
- Lions Eye Institute Ltd., Nedlands, WA, Australia
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7
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Haq W, Zrenner E, Ueffing M, Paquet-Durand F. Using Micro-Electrode-Array Recordings and Retinal Disease Models to Elucidate Visual Functions: Simultaneous Recording of Local Electroretinograms and Ganglion Cell Action Potentials Reveals the Origin of Retinal Oscillatory Potentials. Bioengineering (Basel) 2023; 10:725. [PMID: 37370656 DOI: 10.3390/bioengineering10060725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND The electroretinogram (ERG) is an essential diagnostic tool for visual function, both in clinical and research settings. Here, we establish an advanced in vitro approach to assess cell-type-specific ERG signal components. METHODS Retinal explant cultures, maintained under entirely controlled conditions, were derived from wild-type mice and rd10 rod- and cpfl1 cone-degeneration mouse models. Local micro-ERG (µERG) and simultaneous ganglion cell (GC) recordings were obtained from the retinal explants using multi-electrode arrays. Band-pass filtering was employed to distinguish photoreceptor, bipolar cell, amacrine cell (AC), and GC responses. RESULTS Scotopic and photopic stimulation discriminated between rod and cone responses in wild-type and mutant retina. The 25 kHz sampling rate allowed the visualization of oscillatory potentials (OPs) in extraordinary detail, revealing temporal correlations between OPs and GC responses. Pharmacological isolation of different retinal circuits found that OPs are generated by inner retinal AC electrical synapses. Importantly, this AC activity helped synchronise GC activity. CONCLUSION Our µERG protocol simultaneously records the light-dependent activities of the first-, second-, and third-order neurons within the native neuronal circuitry, providing unprecedented insights into retinal physiology and pathophysiology. This method now also enables complete in vitro retinal function testing of therapeutic interventions, providing critical guidance for later in vivo investigations.
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Affiliation(s)
- Wadood Haq
- Centre for Ophthalmology, Institute for Ophthalmic Research, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
| | - Eberhart Zrenner
- Centre for Ophthalmology, Institute for Ophthalmic Research, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
| | - Marius Ueffing
- Centre for Ophthalmology, Institute for Ophthalmic Research, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
| | - François Paquet-Durand
- Centre for Ophthalmology, Institute for Ophthalmic Research, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
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8
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Vincent A, Ahmed K, Hussein R, Berberovic Z, Tumber A, Zhao X, Minassian BA. Retinal Phenotyping of a Murine Model of Lafora Disease. Genes (Basel) 2023; 14:genes14040854. [PMID: 37107612 PMCID: PMC10137594 DOI: 10.3390/genes14040854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023] Open
Abstract
Lafora disease (LD) is a progressive neurologic disorder caused by biallelic pathogenic variants in EPM2A or EPM2B, leading to tissue accumulation of polyglucosan aggregates termed Lafora bodies (LBs). This study aimed to characterize the retinal phenotype in Epm2a−/− mice by examining knockout (KO; Epm2a−/−) and control (WT) littermates at two time points (10 and 14 months, respectively). In vivo exams included electroretinogram (ERG) testing, optical coherence tomography (OCT) and retinal photography. Ex vivo retinal testing included Periodic acid Schiff Diastase (PASD) staining, followed by imaging to assess and quantify LB deposition. There was no significant difference in any dark-adapted or light-adapted ERG parameters between KO and WT mice. The total retinal thickness was cFigure mparable between the groups and the retinal appearance was normal in both groups. On PASD staining, LBs were observed in KO mice within the inner and outer plexiform layers and in the inner nuclear layer. The average number of LBs within the inner plexiform layer in KO mice were 1743 ± 533 and 2615 ± 915 per mm2, at 10 and 14 months, respectively. This is the first study to characterize the retinal phenotype in an Epm2a−/− mouse model, demonstrating significant LB deposition in the bipolar cell nuclear layer and its synapses. This finding may be used to monitor the efficacy of experimental treatments in mouse models.
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Affiliation(s)
- Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada
| | - Kashif Ahmed
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Rowaida Hussein
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | | | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Xiaochu Zhao
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Berge A. Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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9
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Lee PY, Zhao D, Wong VHY, Hoang A, Tran KKN, van Koeverden AK, Afiat BC, Nguyen CTO, Bui BV. Measuring the Full-Field Electroretinogram in Rodents. Methods Mol Biol 2023; 2708:131-140. [PMID: 37558967 DOI: 10.1007/978-1-0716-3409-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Electroretinography allows for noninvasive functional assessment of the retina and is a mainstay for preclinical studies of retinal function in health and disease. The full-field electroretinogram is useful for a variety of applications as it returns a functional readout from each of the major cell classes within the retina: photoreceptors, bipolar cells, amacrine cells, and retinal ganglion cells. Rodent models are commonly employed in ocular degeneration studies due to the fast throughput of these mammalian species and the conservation of the electroretinogram from the preclinic to the clinic. Here we describe approaches for in vivo electroretinography in rodent models.
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Affiliation(s)
- Pei Ying Lee
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Anh Hoang
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Katie K N Tran
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Anna K van Koeverden
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Brianna C Afiat
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia.
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10
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Pasmanter N, Petersen-Jones SM. Characterization of scotopic and mesopic rod signaling pathways in dogs using the On-Off electroretinogram. BMC Vet Res 2022; 18:422. [PMID: 36463174 PMCID: PMC9719241 DOI: 10.1186/s12917-022-03505-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/07/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The On-Off, or long flash, full field electroretinogram (ERG) separates retinal responses to flash onset and offset. Depending on degree of dark-adaptation and stimulus strength the On and Off ERG can be shaped by rod and cone photoreceptors and postreceptoral cells, including ON and OFF bipolar cells. Interspecies differences have been shown, with predominantly positive Off-response in humans and other primates and a negative Off-response in rodents and dogs. However, the rod signaling pathways that contribute to these differential responses have not been characterized. In this study, we designed a long flash protocol in the dog that varied in background luminance and stimulus strength allowing for some rod components to be present to better characterize how rod pathways vary from scotopic to mesopic conditions. RESULTS With low background light the rod a-wave remains while the b-wave is significantly reduced resulting in a predominantly negative waveform in mesopic conditions. Through modeling and subtraction of the rod-driven response, we show that rod bipolar cells saturate with dimmer backgrounds than rod photoreceptors, resulting in rod hyperpolarization contributing to a large underlying negativity with mesopic backgrounds. CONCLUSIONS Reduction in rod bipolar cell responses in mesopic conditions prior to suppression of rod photoreceptor responses may reflect the changes in signaling pathway of rod-driven responses needed to extend the range of lighting conditions over which the retina functions.
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Affiliation(s)
- Nate Pasmanter
- grid.17088.360000 0001 2150 1785Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D208 East Lansing, MI USA
| | - Simon M. Petersen-Jones
- grid.17088.360000 0001 2150 1785Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D208 East Lansing, MI USA
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11
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Overexpression of Neuregulin-1 Type III Has Impact on Visual Function in Mice. Int J Mol Sci 2022; 23:ijms23094489. [PMID: 35562880 PMCID: PMC9104020 DOI: 10.3390/ijms23094489] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/16/2022] [Accepted: 04/17/2022] [Indexed: 12/05/2022] Open
Abstract
Schizophrenia is associated with several brain deficits, including abnormalities in visual processes. Neuregulin-1 (Nrg1) is a family of trophic factors containing an epidermal growth factor (EGF)-like domain. It is thought to play a role in neural development and has been linked to neuropsychiatric disorders. Abnormal Nrg1 expression has been observed in schizophrenia in clinical studies. Moreover, in schizophrenia, there is more and more evidence found about pathological changes of the retina regarding structural, neurochemical and physiological parameters. However, mechanisms of these changes are not well known. To investigate this, we analysed the function of the visual system using electroretinography (ERG) and the measurement of visual evoked potentials (VEP) in transgenic mice overexpressing Nrg1 type III of three different ages (12 weeks, 24 weeks and 55 weeks). ERG amplitudes tended to be higher in transgenic mice than in control mice in 12-week old mice, whereas the amplitudes were almost similar in older mice. VEP amplitudes were larger in transgenic mice at all ages, with significant differences at 12 and 55 weeks (p values between 0.003 and 0.036). Latencies in ERG and VEP measurements did not differ considerably between control mice and transgenic mice at any age. Our data show for the first time that overexpression of Nrg1 type III changed visual function in transgenic mice. Overall, this investigation of visual function in transgenic mice may be helpful to understand corresponding changes that occur in schizophrenia, as they may find use as biomarkers for psychiatric disorders as well as a potential tool for diagnosis in psychiatry.
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12
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Yan J, Li Y, Zhang T, Shen Y. Numb deficiency impairs retinal structure and visual function in mice. Exp Eye Res 2022; 219:109066. [DOI: 10.1016/j.exer.2022.109066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/20/2022] [Accepted: 04/02/2022] [Indexed: 11/25/2022]
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13
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Retinal Degeneration in a Murine Model of Retinal Ischemia by Unilateral Common Carotid Artery Occlusion. BIOMED RESEARCH INTERNATIONAL 2022; 2021:7727648. [PMID: 35005021 PMCID: PMC8741345 DOI: 10.1155/2021/7727648] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 01/21/2023]
Abstract
Retinal degeneration is a progressive retinal damage in ocular vascular diseases. There are several reasons for this, such as occlusion of arteries or veins, diabetic retinopathy, or hereditary retinal diseases. To study pathological mechanisms of retinal degeneration, it is required to develop experimentally reproducible and clinically relevant models. In our previous studies, we developed a murine model of retinal hypoperfusion by unilateral common carotid artery occlusion (UCCAO) which mimics the pathophysiology of ocular ischemic syndrome (OIS) in humans, and described broad pathological mechanisms in the retina after UCCAO. However, there still remain missing pieces of the ocular pathologic process by UCCAO. In this study, we examined those unfound mechanisms. UCCAO was performed on adult mice. Ocular dysfunctions, histological deficits, and inflammation were examined after UCCAO, compared with sham-operated mice. Evaluation values were analyzed by electrophysiological, histological, and molecular biological methods. Eyelid drooping was permanently seen after UCCAO. Induction time point of acute reversible cataract under anesthesia was shortened. Retinal/visual dysfunctions were detected 2-4 weeks after UCCAO. Specifically, scotopic b-wave was more affected than a-wave, with the dysfunction of photopic b-wave. Impaired oscillatory potentials and visual evoked potential were constantly observed. Pathological Müller gliosis/inflammation was featured with NeuN-positive cell loss in the ganglion cell layer. Axial length, intraocular pressure, pupillary light reflex, and retinal pigment epithelium/choroidal thickness were not changed by UCCAO. A murine model of retinal ischemia by UCCAO can be useful for studying a series of degenerative process in the ischemic retina.
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14
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ERG assessment of altered retinal function in canine models of retinitis pigmentosa and monitoring of response to translatable gene augmentation therapy. Doc Ophthalmol 2021; 143:171-184. [PMID: 33818677 DOI: 10.1007/s10633-021-09832-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE To analyze ERG responses from two dog models of retinitis pigmentosa, one due to a PDE6A mutation and the other a CNGB1 mutation, both to assess the effect of these mutations on retinal function and the ability of gene augmentation therapy to restore normal function. METHODS Scotopic and photopic ERGs from young affected and normal control dogs and affected dogs following AAV-mediated gene augmentation therapy were analyzed. Parameters reflecting rod and cone function were collected by modeling the descending slope of the a-wave to measure receptor response and sensitivity. Rod-driven responses were further assessed by Naka-Rushton fitting of the first limb of the scotopic b-wave luminance-response plot. RESULTS PDE6A-/- dogs showed a dramatic decrease in rod-driven responses with very reduced rod maximal responses and sensitivity. There was a minor reduction in the amplitude of maximal cone responses. In contrast, CNGB1-/- dogs had some residual rod responses with reduced amplitude and sensitivity and normal cone responses. Following gene augmentation therapy, rod parameters were substantially improved in both models with restoration of sensitivity parameters log S and log K and a large increase in log Rmax in keeping with rescue of normal rod phototransduction in the treated retinal regions. CONCLUSIONS Modeling of rod and cone a-waves and the luminance-response function of the scotopic b-wave characterized the loss of rod photoreceptor function in two dog models of retinitis pigmentosa and showed the effectiveness of gene augmentation therapy in restoring normal functional parameters.
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Abstract
Diabetic retinopathy is now well understood as a neurovascular disease. Significant deficits early in diabetes are found in the inner retina that consists of bipolar cells that receive inputs from rod and cone photoreceptors, ganglion cells that receive inputs from bipolar cells, and amacrine cells that modulate these connections. These functional deficits can be measured in vivo in diabetic humans and animal models using the electroretinogram (ERG) and behavioral visual testing. Early effects of diabetes on both the human and animal model ERGs are changes to the oscillatory potentials that suggest dysfunctional communication between amacrine cells and bipolar cells as well as ERG measures that suggest ganglion cell dysfunction. These are coupled with changes in contrast sensitivity that suggest inner retinal changes. Mechanistic in vitro neuronal studies have suggested that these inner retinal changes are due to decreased inhibition in the retina, potentially due to decreased gamma aminobutyric acid (GABA) release, increased glutamate release, and increased excitation of retinal ganglion cells. Inner retinal deficits in dopamine levels have also been observed that can be reversed to limit inner retinal damage. Inner retinal targets present a promising new avenue for therapies for early-stage diabetic eye disease.
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16
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Pasmanter N, Petersen-Jones SM. A review of electroretinography waveforms and models and their application in the dog. Vet Ophthalmol 2020; 23:418-435. [PMID: 32196872 DOI: 10.1111/vop.12759] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 02/04/2023]
Abstract
Electroretinography (ERG) is a commonly used technique to study retinal function in both clinical and research ophthalmology. ERG responses can be divided into component waveforms, analysis of which can provide insight into the health and function of different types and populations of retinal cells. In dogs, ERG has been used in the characterization of normal retinal function, as well as the diagnosis of retinal diseases and measuring effects of treatment. While many components of the recorded waveform are similar across species, dogs have several notable features that should be differentiated from the responses in humans and other animals. Additionally, modifications of standard protocols, such as changing flash frequency and stimulus color, and mathematical models of ERG waveforms have been used in studies of human retinal function but have been infrequently applied to visual electrophysiology in dogs. This review provides an overview of the origins and applications of ERG in addition to potential avenues for further characterization of responses in the dog.
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Affiliation(s)
- Nathaniel Pasmanter
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
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17
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Chan K, Hoon M, Pattnaik BR, Ver Hoeve JN, Wahlgren B, Gloe S, Williams J, Wetherbee B, Kiland JA, Vogel KR, Jansen E, Salomons G, Walters D, Roullet JB, Gibson K M, McLellan GJ. Vigabatrin-Induced Retinal Functional Alterations and Second-Order Neuron Plasticity in C57BL/6J Mice. Invest Ophthalmol Vis Sci 2020; 61:17. [PMID: 32053727 PMCID: PMC7326505 DOI: 10.1167/iovs.61.2.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/07/2019] [Indexed: 12/13/2022] Open
Abstract
Purpose Vigabatrin (VGB) is an effective antiepileptic that increases concentrations of inhibitory γ-aminobutyric acid (GABA) by inhibiting GABA transaminase. Reports of VGB-associated visual field loss limit its clinical usefulness, and retinal toxicity studies in laboratory animals have yielded conflicting results. Methods We examined the functional and morphologic effects of VGB in C57BL/6J mice that received either VGB or saline IP from 10 to 18 weeks of age. Retinal structure and function were assessed in vivo by optical coherence tomography (OCT), ERG, and optomotor response. After euthanasia, retinas were processed for immunohistochemistry, and retinal GABA, and VGB quantified by mass spectrometry. Results No significant differences in visual acuity or total retinal thickness were identified between groups by optomotor response or optical coherence tomography, respectively. After 4 weeks of VGB treatment, ERG b-wave amplitude was enhanced, and amplitudes of oscillatory potentials were reduced. Dramatic rod and cone bipolar and horizontal cell remodeling, with extension of dendrites into the outer nuclear layer, was observed in retinas of VGB-treated mice. VGB treatment resulted in a mean 3.3-fold increase in retinal GABA concentration relative to controls and retinal VGB concentrations that were 20-fold greater than brain. Conclusions No evidence of significant retinal thinning or ERG a- or b-wave deficits were apparent, although we describe significant alterations in ERG b-wave and oscillatory potentials and in retinal cell morphology in VGB-treated C57BL/6J mice. The dramatic concentration of VGB in retina relative to the target tissue (brain), with a corresponding increase in retinal GABA, offers insight into the pathophysiology of VGB-associated visual field loss.
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Affiliation(s)
- Kore Chan
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Mrinalini Hoon
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Bikash R. Pattnaik
- McPherson Eye Research Institute, Madison, Wisconsin, United States
- Pediatrics Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - James N. Ver Hoeve
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Brad Wahlgren
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Shawna Gloe
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Jeremy Williams
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Brenna Wetherbee
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Julie A. Kiland
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Kara R. Vogel
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Erwin Jansen
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Gajja Salomons
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Dana Walters
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - Jean-Baptiste Roullet
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - K Michael Gibson
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - Gillian J. McLellan
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
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18
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Joachimsthaler A, Kremers J. Mouse Cones Adapt Fast, Rods Slowly In Vivo. Invest Ophthalmol Vis Sci 2019; 60:2152-2164. [PMID: 31100107 DOI: 10.1167/iovs.18-26356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To study rod- and cone-driven adaptation dynamics separately, we used the silent substitution technique to selectively stimulate rods or cones in the Opn1lwLIAIS (LIAIS) mouse, in which the native M-cone pigment is replaced by a human L-cone pigment (L*). Methods ERG recordings were performed on anesthetized LIAIS mice. ERG stimuli were sinusoidally modulated. After 10 minutes of adaptation to 0.4 candela per square meter (cd/m2) ERGs were measured, followed by 11-minute adaptation to 8.8 cd/m2 background and recordings directly after the luminance increase and every second minute. Finally, during adaptation to 0.4 cd/m2 for 32 minutes, ERG responses were recorded directly after the change in background and every second minute. This protocol was repeated with rod-isolating stimuli (8 Hz; 75% rod contrast), L*-cone-isolating stimuli (12 Hz; 55% cone contrast) and white light (8 Hz and 12 Hz; 100% Michelson contrast). Results At 8.8 cd/m2, responses directly displayed photopic response properties without further changes in either cone or white light responses. Rod-driven responses were very small. After the return to 0.4 cd/m2, both rod-driven and white light responses increased over a time course of about 30 minutes. Cone-driven responses were very small. Response phases changed directly after a change in background without further alterations. Conclusions Rod- and cone-driven signal pathways display strongly different adaptation characteristics: adaptation of cone-driven responses to photopic conditions is very fast, whereas rod-driven responses change with a time course up to 30 minutes during scotopic conditions. Luminance responses are cone-driven at 8.8 cd/m2 and rod-driven at 0.4 cd/m2.
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Affiliation(s)
- Anneka Joachimsthaler
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.,Animal Physiology, Department of Biology, FAU Erlangen-Nürnberg, Erlangen, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.,Department of Anatomy II, FAU Erlangen-Nürnberg, Erlangen, Germany.,School of Optometry and Vision Science, University of Bradford, Bradford, United Kingdom
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19
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Lee H, Scott J, Griffiths H, Self JE, Lotery A. Oral levodopa rescues retinal morphology and visual function in a murine model of human albinism. Pigment Cell Melanoma Res 2019; 32:657-671. [PMID: 30851223 PMCID: PMC6766973 DOI: 10.1111/pcmr.12782] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/07/2019] [Accepted: 03/04/2019] [Indexed: 01/10/2023]
Abstract
Albinism is a group of disorders characterized by pigment deficiency and abnormal retinal development. Despite being a common cause for visual impairment worldwide, there is a paucity of treatments and patients typically suffer lifelong visual disability. Residual plasticity of the developing retina in young children with albinism has been demonstrated, suggesting a post-natal window for therapeutic rescue. L-3, 4 dihydroxyphenylalanine (L-DOPA), a key signalling molecule which is essential for normal retinal development, is known to be deficient in albinism. In this study, we demonstrate for the first time that post-natal L-DOPA supplementation can rescue retinal development, morphology and visual function in a murine model of human albinism, but only if administered from birth or 15 days post-natal age.
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Affiliation(s)
- Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Jennifer Scott
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK
| | - Helen Griffiths
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Andrew Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
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20
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Yu M, Peachey NS. Use of Direct Current Electroretinography for Analysis of Retinal Pigment Epithelium Function in Mouse Models. Methods Mol Biol 2019; 1753:103-113. [PMID: 29564784 DOI: 10.1007/978-1-4939-7720-8_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
A monolayer of pigmented epithelial cells, the retinal pigment epithelium (RPE), supports photoreceptor function in many ways. Consistent with these roles, RPE dysfunction underlies a number of hereditary retinal disorders. To monitor RPE function in vivo models for these conditions, we adapted an electroretinographic (ERG) technique based on direct current amplification (DC-ERG). This chapter describes the main features of this approach and its application to mouse models involving the RPE.
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Affiliation(s)
- Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA. .,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
| | - Neal S Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
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21
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Eriksen AZ, Eliasen R, Oswald J, Kempen PJ, Melander F, Andresen TL, Young M, Baranov P, Urquhart AJ. Multifarious Biologic Loaded Liposomes that Stimulate the Mammalian Target of Rapamycin Signaling Pathway Show Retina Neuroprotection after Retina Damage. ACS NANO 2018; 12:7497-7508. [PMID: 30004669 PMCID: PMC6117751 DOI: 10.1021/acsnano.8b00596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 07/13/2018] [Indexed: 05/08/2023]
Abstract
A common event in optic neuropathies is the loss of axons and death of retinal ganglion cells (RGCs) resulting in irreversible blindness. Mammalian target of rapamycin (mTOR) signaling pathway agonists have been shown to foster axon regeneration and RGC survival in animal models of optic nerve damage. However, many challenges remain in developing therapies that exploit cell growth and tissue remodeling including (i) activating/inhibiting cell pathways synergistically, (ii) avoiding tumorigenesis, and (iii) ensuring appropriate physiological tissue function. These challenges are further exacerbated by the need to overcome ocular physiological barriers and clearance mechanisms. Here we present liposomes loaded with multiple mTOR pathway stimulating biologics designed to enhance neuroprotection after retina damage. Liposomes were loaded with ciliary neurotrophic factor, insulin-like growth factor 1, a lipopeptide N-fragment osteopontin mimic, and lipopeptide phosphatase tension homologue inhibitors for either the ATP domain or the c-terminal tail. In a mouse model of N-methyl-d-aspartic acid induced RGC death, a single intravitreal administration of liposomes reduced both RGC death and loss of retina electrophysiological function. Furthermore, combining liposomes with transplantation of induced pluripotent stem cell derived RGCs led to an improved electrophysiological outcome in mice. The results presented here show that liposomes carrying multiple signaling pathway modulators can facilitate neuroprotection and transplant electrophysiological outcome.
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Affiliation(s)
- Anne Z. Eriksen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Rasmus Eliasen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Julia Oswald
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Paul J. Kempen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Fredrik Melander
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Thomas L. Andresen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Michael Young
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Petr Baranov
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Andrew J. Urquhart
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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22
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Wei W, Liu B, Jiang H, Jin K, Xiang M. Requirement of the Mowat-Wilson Syndrome Gene Zeb2 in the Differentiation and Maintenance of Non-photoreceptor Cell Types During Retinal Development. Mol Neurobiol 2018; 56:1719-1736. [PMID: 29922981 DOI: 10.1007/s12035-018-1186-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/07/2018] [Indexed: 12/01/2022]
Abstract
Mutations in the human transcription factor gene ZEB2 cause Mowat-Wilson syndrome, a congenital disorder characterized by multiple and variable anomalies including microcephaly, Hirschsprung disease, intellectual disability, epilepsy, microphthalmia, retinal coloboma, and/or optic nerve hypoplasia. Zeb2 in mice is involved in patterning neural and lens epithelia, neural tube closure, as well as in the specification, differentiation and migration of neural crest cells and cortical neurons. At present, it is still unclear how Zeb2 mutations cause retinal coloboma, whether Zeb2 inactivation results in retinal degeneration, and whether Zeb2 is sufficient to promote the differentiation of different retinal cell types. Here, we show that during mouse retinal development, Zeb2 is expressed transiently in early retinal progenitors and in all non-photoreceptor cell types including bipolar, amacrine, horizontal, ganglion, and Müller glial cells. Its retina-specific ablation causes severe loss of all non-photoreceptor cell types, cell fate switch to photoreceptors by retinal progenitors, and elevated apoptosis, which lead to age-dependent retinal degeneration, optic nerve hypoplasia, synaptic connection defects, and impaired ERG (electroretinogram) responses. Moreover, overexpression of Zeb2 is sufficient to promote the fate of all non-photoreceptor cell types at the expense of photoreceptors. Together, our data not only suggest that Zeb2 is both necessary and sufficient for the differentiation of non-photoreceptor cell types while simultaneously inhibiting the photoreceptor cell fate by repressing transcription factor genes involved in photoreceptor specification and differentiation, but also reveal a necessity of Zeb2 in the long-term maintenance of retinal cell types. This work helps to decipher the etiology of retinal atrophy associated with Mowat-Wilson syndrome and hence will impact on clinical diagnosis and management of the patients suffering from this syndrome.
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Affiliation(s)
- Wen Wei
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Bin Liu
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China.,Institute for Metabolic and Neuropsychiatric Disorders, Binzhou Medical University Hospital, Binzhou, China
| | - Haisong Jiang
- Center for Advanced Biotechnology and Medicine and Department of Pediatrics, Rutgers University-Robert Wood Johnson Medical School, 679 Hoes Lane West, Piscataway, NJ, 08854, USA
| | - Kangxin Jin
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China.
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China. .,Center for Advanced Biotechnology and Medicine and Department of Pediatrics, Rutgers University-Robert Wood Johnson Medical School, 679 Hoes Lane West, Piscataway, NJ, 08854, USA. .,Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.
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23
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Zhang Y, Zhao L, Wang X, Ma W, Lazere A, Qian HH, Zhang J, Abu-Asab M, Fariss RN, Roger JE, Wong WT. Repopulating retinal microglia restore endogenous organization and function under CX3CL1-CX3CR1 regulation. SCIENCE ADVANCES 2018; 4:eaap8492. [PMID: 29750189 PMCID: PMC5943055 DOI: 10.1126/sciadv.aap8492] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 02/12/2018] [Indexed: 05/30/2023]
Abstract
Microglia have been discovered to undergo repopulation following ablation. However, the functionality of repopulated microglia and the mechanisms regulating microglia repopulation are unknown. We examined microglial homeostasis in the adult mouse retina, a specialized neural compartment containing regular arrays of microglia in discrete synaptic laminae that can be directly visualized. Using in vivo imaging and cell-fate mapping techniques, we discovered that repopulation originated from residual microglia proliferating in the central inner retina that subsequently spread by centrifugal migration to fully recapitulate pre-existing microglial distributions and morphologies. Repopulating cells fully restored microglial functions including constitutive "surveying" process movements, behavioral and physiological responses to retinal injury, and maintenance of synaptic structure and function. Microglial repopulation was regulated by CX3CL1-CX3CR1 signaling, slowing in CX3CR1 deficiency and accelerating with exogenous CX3CL1 administration. Microglial homeostasis following perturbation can fully recover microglial organization and function under the regulation of chemokine signaling between neurons and microglia.
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Affiliation(s)
- Yikui Zhang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical University, Wenzhou 325027, China
| | - Lian Zhao
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xu Wang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wenxin Ma
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Adam Lazere
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hao-hua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jun Zhang
- Synaptic Physiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mones Abu-Asab
- Section on Histopathology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert N. Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jerome E. Roger
- Centre d’Etude et de Recherche Thérapeutique en Ophtalmologie (CERTO), Retina France, Orsay, France
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Wai T. Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Orexin-B modulates synaptic transmission of rod bipolar cells in rat retina. Neuropharmacology 2018; 133:38-50. [PMID: 29325900 DOI: 10.1016/j.neuropharm.2018.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/31/2017] [Accepted: 01/04/2018] [Indexed: 12/16/2022]
Abstract
Orexin-A, -B play a crucial role in arousal and feeding by activating two G-protein-coupled receptors: orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R). Orexins, along with orexin receptors, are expressed in retinal neurons, and they have been shown to differentially modulate excitatory AMPA receptors of amacrine and ganglion cells in the inner retina. In this work we report that orexin-B modulates the activity of rod bipolar cells (RBCs) located in the outer retina of rat. Intravitreal injection of orexin-B increased the amplitude of the scotopic electroretinographic b-wave, a reflection of RBC activity, recorded in vivo. Patch clamp recordings in rat retinal slices showed that orexin-B did not change glutamatergic excitatory component of the RBC response driven by photoreceptors. Effects of orexin-B on GABA receptor-mediated synaptic transmission of RBCs were then examined. In retinal slice preparations orexin-B suppressed GABA receptor-mediated inhibitory postsynaptic currents of RBCs in the inner plexiform layer. Furthermore, using whole-cell recordings in isolated RBCs it was shown that orexin-B suppressed GABAC receptor-, but not GABAA receptor-, mediated currents of the RBCs, an effect that was blocked by OX1R and OX2R antagonists. The orexin-B-induced inhibition of GABAC currents was likely mediated by a Gi/o/PC-PLC/Ca2+-independent PKC signaling pathway, as such inhibition was absent when each step of the above-pathway was blocked with GDP-β-S/pertussis toxin (for Gi/o), D609 (for PLC), bisindolylmaleimide IV (for PKC)/rottlerin (for PKCδ), respectively. The orexin-B-induced potentiation of RBC activity may improve visual acuity and contrast sensitivity of the animal during the dark period (wake phase).
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Dopamine-Dependent Sensitization of Rod Bipolar Cells by GABA Is Conveyed through Wide-Field Amacrine Cells. J Neurosci 2017; 38:723-732. [PMID: 29217689 DOI: 10.1523/jneurosci.1994-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 11/15/2017] [Accepted: 11/21/2017] [Indexed: 11/21/2022] Open
Abstract
The vertebrate retina has the remarkable ability to support visual function under conditions of limited illumination, including the processing of signals evoked by single photons. Dim-light vision is regulated by several adaptive mechanisms. The mechanism explored in this study is responsible for increasing the light sensitivity and operational range of rod bipolar cells, the retinal neurons operating immediately downstream of rod photoreceptors. This sensitization is achieved through the sustained dopamine-dependent GABA release from other retinal neurons. Our goals were to identify the cell type responsible for the GABA release and the site of its modulation by dopamine. Previous studies have suggested the involvement of amacrine and/or horizontal cells. We now demonstrate, using mice of both sexes, that horizontal cells do not participate in this mechanism. Instead, sustained GABA input is provided by a subpopulation of wide-field amacrine cells, which stimulate the GABAC receptors at rod bipolar cell axons. We also found that dopamine does not act directly on either of these cells. Rather, it suppresses inhibition imposed on these wide-field cells by another subpopulation of upstream GABAergic amacrine cells, thereby sustaining the GABAC receptor activation required for rod bipolar cell sensitization.SIGNIFICANCE STATEMENT The vertebrate retina has an exquisite ability to adjust information processing to ever-changing conditions of ambient illumination, from bright sunlight to single-photon counting under dim starlight. Operation under each of these functional regimes requires an engagement of specific adaptation mechanisms. Here, we describe a mechanism optimizing the performance of the dim-light channel of vision, which consists of sensitizing rod bipolar cells by a sustained GABAergic input originating from a population of wide-field amacrine cells. Wide-field amacrine cells span large segments of the retina, making them uniquely equipped to normalize and optimize response sensitivity across distant receptive fields and preclude any bias toward local light-intensity fluctuations.
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Joachimsthaler A, Tsai TI, Kremers J. Electrophysiological Studies on The Dynamics of Luminance Adaptation in the Mouse Retina. Vision (Basel) 2017; 1:vision1040023. [PMID: 31740648 PMCID: PMC6835873 DOI: 10.3390/vision1040023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/11/2017] [Accepted: 10/15/2017] [Indexed: 12/31/2022] Open
Abstract
To date, most studies involving in vivo electroretinography in mice are performed on steady state adapted animals. In this study, we focused on the dynamics of adaptation to high and low light levels in the mouse retina. Two flash electroretinogram (ERG) protocols and one flicker ERG protocol were employed. In the two flash ERG protocols, the animals were adapted to either 25 or 40 cd/m2 white light and ERGs were recorded for up to 15 min of adaptation. Afterwards, flash ERGs were recorded for up to 45 min of dark adaptation. Amplitudes of the flash ERG increased during light adaptation, while implicit times of the different wave components decreased. During subsequent dark adaptation, the amplitudes further increased. The increase in a-to-b-wave ratio indicated adaptational processes at the photoreceptor synapse. In the flicker ERG protocol, the responses to 12 Hz sinusoidal luminance modulation during the adaptation to 25 cd/m2 and a 1 cd/m2 mean luminances were recorded. The amplitudes of the first harmonic components in the flicker protocol decreased during light adaptation but increased during dark adaptation. This is at odds with the changes in the flash ERG, indicating that adaptation may be different in different retinal pathways.
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Affiliation(s)
- Anneka Joachimsthaler
- Department of Ophthamlology, University Hospital Erlangen, 91054 Erlangen, Germany
- Department of Biology, Animal Physiology, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Tina I. Tsai
- Department of Ophthamlology, University Hospital Erlangen, 91054 Erlangen, Germany
- Department of Biology, Animal Physiology, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Jan Kremers
- Department of Ophthamlology, University Hospital Erlangen, 91054 Erlangen, Germany
- Correspondence:
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Dai J, He J, Wang G, Wang M, Li S, Yin ZQ. Contribution of GABAa, GABAc and glycine receptors to rat dark-adapted oscillatory potentials in the time and frequency domain. Oncotarget 2017; 8:77696-77709. [PMID: 29100418 PMCID: PMC5652335 DOI: 10.18632/oncotarget.20770] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/29/2017] [Indexed: 02/02/2023] Open
Abstract
Retinal oscillatory potentials (OPs) consist of a series of relatively high-frequency rhythmic wavelets, superimposed onto the ascending phase of the b-wave of the electroretinogram (ERG). However, the origin of OPs is uncertain and methods of measurement of OPs are diverse. In this study, we first isolated OPs from the rat ERG and fitted them with Gabor functions and found that the envelope of the OP contained information about maximum amplitude and time-to-peak to enable satisfactory quantification of the later OPs. And the OP/b-wave ratio should be evaluated to exclude an effect of the b-wave on the OPs. Next, we recorded OPs after intravitreal injection of 2-amino-4-phosphonobutyric acid (APB), tetrodotoxin (TTX), γ-aminobutyric acid (GABA), strychnine (STR), SR95531 (SR), isoguvacine (ISO), (1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA) and GABA+TPMPA. We showed that GABA and APB only removed the later OPs, when compared to control eyes. TTX delayed the peak time, and STR, SR and ISO reduced the amplitude of OPs. TPMPA delayed the peak time but increased the ratio of OPs to b-wave. Furthermore, administration of combined GABA and TPMPA caused the later OPs to increase in amplitude with time, compared with those after delivery of GABA alone. Finally, we observed that GABAc and glycine receptors contributed to a low-frequency component of the OPs, while GABAa contributed to both components. These results suggest that the early components of the OPs are mainly generated by the photoreceptors, whilst the later components are mainly regulated by GABAa, GABAc and glycine receptors.
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Affiliation(s)
- Jiaman Dai
- College of Bioengineering, Chongqing University, Chongqing 400030, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China
| | - Juncai He
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China
| | - Gang Wang
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China
| | - Min Wang
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China
| | - Shiying Li
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China
| | - Zheng Qin Yin
- College of Bioengineering, Chongqing University, Chongqing 400030, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing 400038, China.,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China
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Dai J, Fu Y, Zeng Y, Li S, Qin Yin Z. Improved retinal function in RCS rats after suppressing the over-activation of mGluR5. Sci Rep 2017; 7:3546. [PMID: 28615682 PMCID: PMC5471183 DOI: 10.1038/s41598-017-03702-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/03/2017] [Indexed: 01/09/2023] Open
Abstract
Müller cells maintain retinal synaptic homeostasis by taking up glutamate from the synaptic cleft and transporting glutamine back to the neurons. To study the interaction between Müller cells and photoreceptors, we injected either DL-α-aminoadipate or L-methionine sulfoximine–both inhibitors of glutamine synthetase–subretinally in rats. Following injection, the a-wave of the electroretinogram (ERG) was attenuated, and metabotropic glutamate receptor 5 (mGluR5) was activated. Selective antagonism of mGluR5 by 2-methyl-6-(phenylethynyl)-pyridine increased the ERG a-wave amplitude and also increased rhodopsin expression. Conversely, activation of mGluR5 by the agonist, (R,S)-2-chloro-5-hydroxyphenylglycine, decreased both the a-wave amplitude and rhodopsin expression, but upregulated expression of Gq alpha subunit and phospholipase C βIII. Overexpression of mGluR5 reduced the inward-rectifying potassium ion channel (Kir) current and decreased the expression of Kir4.1 and aquaporin-4 (AQP4). Further experiments indicated that mGluR5 formed a macromolecular complex with these two membrane channels. Lastly, increased expression of mGluR5 was found in Royal College of Surgeons rats–a model of retinitis pigmentosa (RP). Inhibition of mGluR5 in this model restored the amplitude of ERG features, and reduced the expression of glial fibrillary acidic protein. These results suggest that mGluR5 may be worth considering as a potential therapeutic target in RP.
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Affiliation(s)
- Jiaman Dai
- Bioengineering College, Chongqing University, Chongqing, 400040, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China
| | - Yan Fu
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China
| | - Yuxiao Zeng
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China.,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China
| | - Shiying Li
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China. .,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China.
| | - Zheng Qin Yin
- Bioengineering College, Chongqing University, Chongqing, 400040, China. .,Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China. .,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, 400038, China.
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Asteriti S, Gargini C, Cangiano L. Connexin 36 expression is required for electrical coupling between mouse rods and cones. Vis Neurosci 2017; 34:E006. [PMID: 28965521 DOI: 10.1017/s0952523817000037] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Rod-cone gap junctions mediate the so-called "secondary rod pathway", one of three routes that convey rod photoreceptor signals across the retina. Connexin 36 (Cx36) is expressed at these gap junctions, but an unidentified connexin protein also seems to be expressed. Cx36 knockout mice have been used extensively in the quest to dissect the roles in vision of all three pathways, with the assumption, never directly tested, that rod-cone electrical coupling is abolished by deletion of this connexin isoform. We previously showed that when wild type mouse cones couple to rods, their apparent dynamic range is extended toward lower light intensities, with the appearance of large responses to dim flashes (up to several mV) originating in rods. Here we recorded from the cones of Cx36del[LacZ]/del[LacZ] mice and found that dim flashes of the same intensity evoked at most small sub-millivolt responses. Moreover, these residual responses originated in the cones themselves, since: (i) their spectral preference matched that of the recorded cone and not of rods, (ii) their time-to-peak was shorter than in coupled wild type cones, (iii) a pharmacological block of gap junctions did not reduce their amplitude. Taken together, our data show that rod signals are indeed absent in the cones of Cx36 knockout mice. This study is the first direct demonstration that Cx36 is crucial for the assembly of functional rod-cone gap junctional channels, implying that its genetic deletion is a reliable experimental approach to eliminate rod-cone coupling.
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Affiliation(s)
- Sabrina Asteriti
- Department of Translational Research,University of Pisa,Pisa,Italy
| | | | - Lorenzo Cangiano
- Department of Translational Research,University of Pisa,Pisa,Italy
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The Shift of ERG B-Wave Induced by Hours' Dark Exposure in Rodents. PLoS One 2016; 11:e0161010. [PMID: 27517462 PMCID: PMC4982619 DOI: 10.1371/journal.pone.0161010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/28/2016] [Indexed: 11/29/2022] Open
Abstract
Purpose Dark adaptation can induce a rapid functional shift in the retina, and after that, the retinal function is believed to remain stable during the continuous dark exposure. However, we found that electroretinograms (ERG) b-waves gradually shifted during 24 hours’ dark exposure in rodents. Detailed experiments were designed to explore this non-classical dark adaptation. Methods In vivo ERG recording in adult and developing rodents after light manipulations. Results We revealed a five-fold decrease in ERG b-waves in adult rats that were dark exposed for 24 hours. The ERG b-waves significantly increased within the first hour’s dark exposure, but after that decreased continuously and finally attained steady state after 1 day’s dark exposure. After 3 repetitive, 10 minutes’ light exposure, the dark exposed rats fully recovered. This recovery effect was eye-specific, and light exposure to one eye could not restore the ERGs in the non-exposed eye. The prolonged dark exposure-induced functional shift was also reflected in the down-regulation on the amplitude of intensity-ERG response curve, but the dynamic range of the responsive light intensity remained largely stable. Furthermore, the ERG b-wave shifts occurred in and beyond classical critical period, and in both rats and mice. Importantly, when ERG b-wave greatly shifted, the amplitude of ERG a-wave did not change significantly after the prolonged dark exposure. Conclusions This rapid age-independent ERG change demonstrates a generally existing functional shift in the retina, which is at the entry level of visual system.
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31
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Chavda S, Luthert PJ, Salt TE. P2X 7R modulation of visually evoked synaptic responses in the retina. Purinergic Signal 2016; 12:611-625. [PMID: 27393519 PMCID: PMC5123999 DOI: 10.1007/s11302-016-9522-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 06/24/2016] [Indexed: 10/29/2022] Open
Abstract
P2X7Rs are distributed throughout all layers of the retina, and thus, their localisation on various cell types puts into question their specific site(s) of action. Using a dark-adapted, ex vivo mouse retinal whole mount preparation, the present study aimed to characterise the effect of P2X7R activation on light-evoked, excitatory RGC ON-field excitatory post-synaptic potentials (fEPSPs) and on outer retinal electroretinogram (ERG) responses under comparable conditions. The pharmacologically isolated NMDA receptor-mediated RGC ON-fEPSP was reduced in the presence of BzATP, an effect which was significantly attenuated by A438079 and other selective P2X7R antagonists A804598 or AF27139. In physiological Krebs medium, BzATP induced a significant potentiation of the ERG a-wave, with a concomitant reduction in the b-wave and the power of the oscillatory potentials. Conversely, in the pharmacologically modified Mg2+-free perfusate, BzATP reduced both the a-wave and b-wave. The effects of BzATP on the ERG components were suppressed by A438079. A role for P2X7R function in visual processing in both the inner and outer retina under physiological conditions remains controversial. The ON-fEPSP was significantly reduced in the presence of A804598 but not by A438079 or AF27139. Furthermore, A438079 did not have any effect on the ERG components in physiological Krebs but potentiated and reduced the a-wave and b-wave, respectively, when applied to the pharmacologically modified medium. Therefore, activation of P2X7Rs affects the function in the retinal ON pathway. The presence of a high concentration of extracellular ATP would most likely contribute to the modulation of visual transmission in the retina in the pathophysiological microenvironment.
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Affiliation(s)
- Seetal Chavda
- Visual Neuroscience, UCL Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Philip J Luthert
- Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, EC1V 9EL, UK.,NIHR Biomedical Research Centre in Ophthalmology, London, EC1V 9EL, UK
| | - Thomas E Salt
- Visual Neuroscience, UCL Institute of Ophthalmology, London, EC1V 9EL, UK.
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Toluene inhalation exposure for 13 weeks causes persistent changes in electroretinograms of Long-Evans rats. Neurotoxicology 2016; 53:257-270. [PMID: 26899397 DOI: 10.1016/j.neuro.2016.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/12/2016] [Accepted: 02/15/2016] [Indexed: 11/22/2022]
Abstract
Studies of humans chronically exposed to volatile organic solvents have reported impaired visual functions, including low contrast sensitivity and reduced color discrimination. These reports, however, lacked confirmation from controlled laboratory experiments. To address this question experimentally, we examined visual function by recording visual evoked potentials (VEP) and/or electroretinograms (ERG) from four sets of rats exposed repeatedly to toluene. In addition, eyes of the rats were examined with an ophthalmoscope and some of the retinal tissues were evaluated for rod and M-cone photoreceptor immunohistochemistry. The first study examined rats following exposure to 0, 10, 100 or 1000ppm toluene by inhalation (6hr/d, 5d/wk) for 13 weeks. One week after the termination of exposure, the rats were implanted with chronically indwelling electrodes and the following week pattern-elicited VEPs were recorded. VEP amplitudes were not significantly changed by toluene exposure. Four to five weeks after completion of exposure, rats were dark-adapted overnight, anesthetized, and several sets of electroretinograms (ERG) were recorded. In dark-adapted ERGs recorded over a 5-log (cd-s/m(2)) range of flash luminance, b-wave amplitudes were significantly reduced at high stimulus luminance values in rats previously exposed to 1000ppm toluene. A second set of rats, exposed concurrently with the first set, was tested approximately one year after the termination of 13 weeks of exposure to toluene. Again, dark-adapted ERG b-wave amplitudes were reduced at high stimulus luminance values in rats previously exposed to 1000ppm toluene. A third set of rats was exposed to the same concentrations of toluene for only 4 weeks, and a fourth set of rats exposed to 0 or 1000ppm toluene for 4 weeks were tested approximately 1year after the completion of exposure. No statistically significant reductions of ERG b-wave amplitude were observed in either set of rats exposed for 4 weeks. No significant changes were observed in ERG a-wave amplitude or latency, b-wave latency, UV- or green-flicker ERGs, or in photopic flash ERGs. There were no changes in the density of rod or M-cone photoreceptors. The ERG b-wave reflects the firing patterns of on-bipolar cells. The reductions of b-wave amplitude after 13 weeks of exposure and persisting for 1year suggest that alterations may have occurred in the inner nuclear layer of the retina, where the bipolar cells reside, or the outer or inner plexiform layers where the bipolar cells make synaptic connections. These data provide experimental evidence that repeated exposure to toluene may lead to subtle persistent changes in visual function. The fact that toluene affected ERGs, but not VEPs, suggests that elements in the rat retina may be more sensitive to organic solvent exposure than the rat visual cortex.
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In vivo electroretinographic studies of the role of GABAC receptors in retinal signal processing. Exp Eye Res 2015; 139:48-63. [PMID: 26164072 DOI: 10.1016/j.exer.2015.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 06/09/2015] [Accepted: 07/07/2015] [Indexed: 11/23/2022]
Abstract
All three classes of receptors for the inhibitory neurotransmitter GABA (GABAR) are expressed in the retina. This study investigated roles of GABAR, especially GABACR (GABA(A)-ρ), in retinal signaling in vivo by studying effects on the mouse electroretinogram (ERG) of genetic deletion of GABACR versus pharmacological blockade using receptor antagonists. Brief full-field flash ERGs were recorded from anesthetized GABACR(-/-) mice, and WT C57BL/6 (B6) mice, before and after intravitreal injection of GABACR antagonists, TPMPA, 3-APMPA, or the more recently developed 2-AEMP; GABAAR antagonist, SR95531; GABABR antagonist, CGP, and agonist, baclofen. Intravitreal injections of TPMPA and SR95531 were also made in Brown Norway rats. The effect of 2-AEMP on GABA-induced current was tested directly in isolated rat rod bipolar cells, and 2-AEMP was found to preferentially block GABACR in those cells. Maximum amplitudes of dark (DA) and light-adapted (LA) ERG b-waves were reduced in GABACR(-/-) mice, compared to B6 mice, by 30-60%; a-waves were unaltered and oscillatory potential amplitudes were increased. In B6 mice, after injection of TPMPA (also in rats), 3-APMPA or 2-AEMP, ERGs became similar to ERGs of GABACR(-/-) mice. Blockade of GABAARs and GABABRs, or agonism of GABABRs did not alter B6 DA b-wave amplitude. The negative scotopic threshold response (nSTR) was slightly less sensitive in GABACR(-/-) than in B6 mice, and unaltered by 2-AEMP. However, amplitudes of nSTR and photopic negative response (PhNR), both of which originate from inner retina, were enhanced by TPMPA and 3-APMPA, each of which has GABAB agonist properties, and further increased by baclofen. The finding that genetic deletion of GABACR, the GABACR antagonist 2-AEMP, and other antagonists all reduced ERG b-wave amplitude, supports a role for GABACR in determining the maximum response amplitude of bipolar cells contributing to the b-wave. GABACR antagonists differed in their effects on nSTR and PhNR; antagonists with GABAB agonist properties enhanced light-driven responses whereas 2-AEMP did not.
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Park JC, Cao D, Collison FT, Fishman GA, McAnany JJ. Rod and cone contributions to the dark-adapted 15-Hz flicker electroretinogram. Doc Ophthalmol 2015; 130:111-9. [PMID: 25579805 DOI: 10.1007/s10633-015-9480-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 01/05/2015] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate rod and cone contributions to the dark-adapted 15-Hz flicker electroretinogram (ERG) across a broad range of stimulus luminances by comparing rod-isolating (ERGR), cone-isolating (ERGC), and non-receptor-specific (ERGR+C) responses. METHODS Dark-adapted, full-field 15-Hz ERGs were obtained from four normally sighted subjects (ages 29-36 years) using a four-primary LED-based stimulating system. The primaries were either modulated sinusoidally in phase (ERGR+C) or were modulated in counter-phase to achieve rod isolation (ERGR) or cone isolation (ERGC) by means of triple silent substitution. Measurements were made for a broad range of luminances (-2.5 to 1.8 log scot. cd/m(2) in 0.2 log unit steps). Fourier analysis was used to obtain the amplitude and phase of the fundamental response component at each stimulus luminance. RESULTS Stimulus luminance had different effects on response amplitudes and phases under the three paradigms. Specifically, ERGC amplitude and phase increased monotonically as luminance increased. The effects on ERGR+C and ERGR were complex: ERGR+C and ERGR amplitude was small and the phase decreased for low luminances, whereas amplitude and phase increased sharply at moderate luminances. For high luminances, ERGR+C amplitude and phase increased, whereas ERGR amplitude decreased and phase was approximately constant. CONCLUSIONS At low luminances, the ERGR+C and ERGR functions can be attributed to interactions between two rod pathways. At high luminances, the functions can be accounted for by interactions between rod and cone pathways (ERGR+C) or rod insensitivity (ERGR). The ERGR paradigm minimizes cone intrusion, permitting assessment of rod function over a large range of luminance levels.
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Affiliation(s)
- Jason C Park
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St., Chicago, IL, 60612, USA
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Liu C, Cao L, Yang S, Xu L, Liu P, Wang F, Xu D. Subretinal injection of amyloid-β peptide accelerates RPE cell senescence and retinal degeneration. Int J Mol Med 2014; 35:169-76. [PMID: 25385658 DOI: 10.3892/ijmm.2014.1993] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/30/2014] [Indexed: 11/06/2022] Open
Abstract
Drusen are considered a hallmark characteristic of age-related macular degeneration (AMD). In our previous study, we found that amyloid-β (Aβ) peptide, a component of drusen, induced the cells of the retinal pigment epithelium (RPE; RPE cells) to enter senescence; however, its effects in vivo remain unknown. Thus, the present study was carried out to explore the in vivo effects of Aβ peptide on RPE cell senescence and senescence-associated inflammation in C57BL/6 mice. C57BL/6 mice received a subretinal injection of Aβ(1-42) peptide; on day 7 post-injection, the mice were anesthetized and subjected to whole-body perfusion with 4% paraformaldehyde (PFA) in PBS and the whole eyes were then enucleated. Retinal function was assessed by electroretinography (ERG), and the morphological characteristics of the retina were examined by light and electron microscopy. Fundus autofluorescence (FAF) was examined by confocal scanning laser ophthalmoscopy (cSLO). The expression of p16INK4a, a marker of cellular senescence, was examined by immunofluorescence staining and western blot analysis. The RPE-choroid was analyzed for cytokine expression by RT-PCR. In Aβ(1-42)-injected mice, scotopic ERG responses declined. Degenerative alterations, including the disruption of the inner segment (IS)/outer segment (OS) junction and extensive vacuolation and thickness of Bruch's membrane (BrM) were observed under a a light microscope. The accumulation of vacuoles and the loss of basal infoldings in the RPE were identified using an electron microscope. FAF and p16INK4a expression increased in Aβ(1-42)-injected mice. In addition, Aβ(1-42) upregulated interleukin (IL)-6 and IL-8 gene expression in the RPE-choroid. In conclusion, our results confirm the effects of Aβ(1-42) peptide on RPE senescence in vivo. The Aβ-injected mice developed AMD-like ocular pathology. It is thus suggested that RPE cell senescence is a potential mechanistic link between inflammation and retinal degeneration.
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Affiliation(s)
- Chaoqi Liu
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Lining Cao
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Shuai Yang
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Linxinyu Xu
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Pei Liu
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Fang Wang
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
| | - Ding Xu
- Department of Ophthalmology, Shanghai Tenth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai 200072, P.R. China
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Popova E. Ionotropic GABA Receptors and Distal Retinal ON and OFF Responses. SCIENTIFICA 2014; 2014:149187. [PMID: 25143858 PMCID: PMC4131092 DOI: 10.1155/2014/149187] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/24/2014] [Accepted: 05/27/2014] [Indexed: 05/27/2023]
Abstract
In the vertebrate retina, visual signals are segregated into parallel ON and OFF pathways, which provide information for light increments and decrements. The segregation is first evident at the level of the ON and OFF bipolar cells in distal retina. The activity of large populations of ON and OFF bipolar cells is reflected in the b- and d-waves of the diffuse electroretinogram (ERG). The role of gamma-aminobutyric acid (GABA), acting through ionotropic GABA receptors in shaping the ON and OFF responses in distal retina, is a matter of debate. This review summarized current knowledge about the types of the GABAergic neurons and ionotropic GABA receptors in the retina as well as the effects of GABA and specific GABAA and GABAC receptor antagonists on the activity of the ON and OFF bipolar cells in both nonmammalian and mammalian retina. Special emphasis is put on the effects on b- and d-waves of the ERG as a useful tool for assessment of the overall function of distal retinal ON and OFF channels. The role of GABAergic system in establishing the ON-OFF asymmetry concerning the time course and absolute and relative sensitivity of the ERG responses under different conditions of light adaptation in amphibian retina is also discussed.
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Affiliation(s)
- E. Popova
- Department of Physiology, Medical Faculty, Medical University, 1431 Sofia, Bulgaria
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Bakhshandeh Bali MK, Otaghsara SMT, Soltansanjari M, Sadighi N, Nasehi MM, Ashrafi MR, Karimzadeh P, Taghdiri MM, Ghofrani M. Electroretinographic responses in epileptic children treated with vigabatrin. J Child Neurol 2014; 29:765-8. [PMID: 23748200 DOI: 10.1177/0883073813490073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/21/2013] [Indexed: 11/17/2022]
Abstract
Vigabatrin is an antiepileptic drug that results in higher gamma-aminobutyrate levels in the brain and retina. Vigabatrin-induced visual field defects are usually asymptomatic and only detectable by perimetry. Further, perimetry requires good cooperation, and children aged under 10 years cannot do it. Electroretinogram response amplitude to full-field 30-Hz flicker shine has been offered to be more specific in predicting visual field defects. This study is scheduled to investigate the vigabatrin-associated visual complications in 67 epileptic children taking vigabatrin using full-field electroretinogram. Electroretinographic surveys showed normal range parameters despite 3 months of vigabatrin treatment, and just 3 (4.47%) children had been visually impaired at the end of 6-month treatment. Among these 3 cases, 1 patient had persistent electroretinogram abnormality despite vigabatrin discontinuation. Our study suggests that vigabatrin is secure for short-term pediatric antiepileptic treatment, with few cases of visual impairments and that are often reversible.
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Affiliation(s)
- M K Bakhshandeh Bali
- Pediatric Neurology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - S M Taheri Otaghsara
- Brain and Spinal Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mostafa Soltansanjari
- Eye Research Center, Rasool Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Nadia Sadighi
- Eye Research Center, Rasool Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Mahdi Nasehi
- Department of Pediatric Neurology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Parvaneh Karimzadeh
- Department of Pediatric Neurology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Mahdi Taghdiri
- Department of Pediatric Neurology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Ghofrani
- Department of Pediatric Neurology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Adekeye A, Haeri M, Solessio E, Knox BE. Ablation of the proapoptotic genes CHOP or Ask1 does not prevent or delay loss of visual function in a P23H transgenic mouse model of retinitis pigmentosa. PLoS One 2014; 9:e83871. [PMID: 24523853 PMCID: PMC3921110 DOI: 10.1371/journal.pone.0083871] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/08/2013] [Indexed: 11/19/2022] Open
Abstract
The P23H mutation in rhodopsin (Rho(P23H)) is a prevalent cause of autosomal dominant retinitis pigmentosa. We examined the role of the ER stress proteins, Chop and Ask1, in regulating the death of rod photoreceptors in a mouse line harboring the Rho(P23H) rhodopsin transgene (GHL(+)). We used knockout mice models to determine whether Chop and Ask1 regulate rod survival or retinal degeneration. Electrophysiological recordings showed similar retinal responses and sensitivities for GHL(+), GHL(+)/Chop(-/-) and GHL(+)/Ask1(-/-) animals between 4-28 weeks, by which time all three mouse lines exhibited severe loss of retinal function. Histologically, ablation of Chop and Ask1 did not rescue photoreceptor loss in young animals. However, in older mice, a regional protective effect was observed in the central retina of GHL(+)/Chop(-/-) and GHL(+)/Ask1(-/-), a region that was severely degenerated in GHL(+) mice. Our results show that in the presence of the Rho(P23H) transgene, the rate of decline in retinal sensitivity is similar in Chop or Ask1 ablated and wild-type retinas, suggesting that these proteins do not play a major role during the acute phase of photoreceptor loss in GHL(+) mice. Instead they may be involved in regulating secondary pathological responses such as inflammation that are upregulated during later stages of disease progression.
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Affiliation(s)
- Adeseye Adekeye
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Mohammad Haeri
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Eduardo Solessio
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Barry E. Knox
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
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Smith BJ, Tremblay F, Côté PD. Voltage-gated sodium channels contribute to the b-wave of the rodent electroretinogram by mediating input to rod bipolar cell GABAc receptors. Exp Eye Res 2013; 116:279-90. [DOI: 10.1016/j.exer.2013.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/23/2013] [Accepted: 09/10/2013] [Indexed: 11/26/2022]
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Baba K, Benleulmi-Chaachoua A, Journé AS, Kamal M, Guillaume JL, Dussaud S, Gbahou F, Yettou K, Liu C, Contreras-Alcantara S, Jockers R, Tosini G. Heteromeric MT1/MT2 melatonin receptors modulate photoreceptor function. Sci Signal 2013; 6:ra89. [PMID: 24106342 DOI: 10.1126/scisignal.2004302] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The formation of G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor (GPCR) heteromers enables signaling diversification and holds great promise for improved drug selectivity. Most studies of these oligomerization events have been conducted in heterologous expression systems, and in vivo validation is lacking in most cases, thus questioning the physiological significance of GPCR heteromerization. The melatonin receptors MT1 and MT2 exist as homomers and heteromers when expressed in cultured cells. We showed that melatonin MT1/MT2 heteromers mediated the effect of melatonin on the light sensitivity of rod photoreceptors in mice. This effect of melatonin involved activation of the heteromer-specific phospholipase C and protein kinase C (PLC/PKC) pathway and was abolished in MT1(-/-) or MT2(-/-) mice, as well as in mice overexpressing a nonfunctional MT2 mutant that interfered with the formation of functional MT1/MT2 heteromers in photoreceptor cells. Not only does this study establish an essential role of melatonin receptor heteromers in retinal function, it also provides in vivo support for the physiological importance of GPCR heteromerization. Thus, the MT1/MT2 heteromer complex may provide a specific pharmacological target to improve photoreceptor function.
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Affiliation(s)
- Kenkichi Baba
- 1Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, GA 30310, USA
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Identifying cell class specific losses from serially generated electroretinogram components. BIOMED RESEARCH INTERNATIONAL 2013; 2013:796362. [PMID: 24089688 PMCID: PMC3781995 DOI: 10.1155/2013/796362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/08/2013] [Indexed: 11/18/2022]
Abstract
Purpose. Processing of information through the cellular layers of the retina occurs in a serial manner. In the electroretinogram (ERG), this complicates interpretation of inner retinal changes as dysfunction may arise from “upstream” neurons or may indicate a direct loss to that neural generator. We propose an approach that addresses this issue by defining ERG gain relationships. Methods. Regression analyses between two serial ERG parameters in a control cohort of rats are used to define gain relationships. These gains are then applied to two models of retinal disease. Results. The PIIIamp to PIIamp gain is unity whereas the PIIamp to pSTRamp and PIIamp to nSTRamp gains are greater than unity, indicating “amplification” (P < 0.05). Timing relationships show amplification between PIIIit to PIIit and compression for PIIit to pSTRit and PIIit to nSTRit, (P < 0.05). Application of these gains to ω-3-deficiency indicates that all timing changes are downstream of photoreceptor changes, but a direct pSTR amplitude loss occurs (P < 0.05). Application to diabetes indicates widespread inner retinal dysfunction which cannot be attributed to outer retinal changes (P < 0.05). Conclusions. This simple approach aids in the interpretation of inner retinal ERG changes by taking into account gain characteristics found between successive ERG components of normal animals.
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Wu F, Li R, Umino Y, Kaczynski TJ, Sapkota D, Li S, Xiang M, Fliesler SJ, Sherry DM, Gannon M, Solessio E, Mu X. Onecut1 is essential for horizontal cell genesis and retinal integrity. J Neurosci 2013; 33:13053-65, 13065a. [PMID: 23926259 PMCID: PMC3735885 DOI: 10.1523/jneurosci.0116-13.2013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 06/24/2013] [Accepted: 07/01/2013] [Indexed: 01/03/2023] Open
Abstract
Horizontal cells are interneurons that synapse with photoreceptors in the outer retina. Their genesis during development is subject to regulation by transcription factors in a hierarchical manner. Previously, we showed that Onecut 1 (Oc1), an atypical homeodomain transcription factor, is expressed in developing horizontal cells (HCs) and retinal ganglion cells (RGCs) in the mouse retina. Herein, by knocking out Oc1 specifically in the developing retina, we show that the majority (∼80%) of HCs fail to form during early retinal development, implying that Oc1 is essential for HC genesis. However, no other retinal cell types, including RGCs, were affected in the Oc1 knock-out. Analysis of the genetic relationship between Oc1 and other transcription factor genes required for HC development revealed that Oc1 functions downstream of FoxN4, in parallel with Ptf1a, but upstream of Lim1 and Prox1. By in utero electroporation, we found that Oc1 and Ptf1a together are not only essential, but also sufficient for determination of HC fate. In addition, the synaptic connections in the outer plexiform layer are defective in Oc1-null mice, and photoreceptors undergo age-dependent degeneration, indicating that HCs are not only an integral part of the retinal circuitry, but also are essential for the survival of photoreceptors. In sum, these results demonstrate that Oc1 is a critical determinant of HC fate, and reveal that HCs are essential for photoreceptor viability, retinal integrity, and normal visual function.
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Affiliation(s)
- Fuguo Wu
- Department of Ophthalmology/Ross Eye Institute and
- Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, New York 14203
- SUNY Eye Institute, Buffalo, New York 14203
| | - Renzhong Li
- Department of Ophthalmology/Ross Eye Institute and
- Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, New York 14203
- SUNY Eye Institute, Buffalo, New York 14203
| | - Yumiko Umino
- SUNY Eye Institute, Buffalo, New York 14203
- Department of Ophthalmology, Upstate Medical University, Syracuse, New York 13210
| | - Tadeusz J. Kaczynski
- Department of Ophthalmology/Ross Eye Institute and
- Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, New York 14203
- SUNY Eye Institute, Buffalo, New York 14203
| | - Darshan Sapkota
- Department of Ophthalmology/Ross Eye Institute and
- Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, New York 14203
- SUNY Eye Institute, Buffalo, New York 14203
| | - Shengguo Li
- Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Mengqing Xiang
- Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Steven J. Fliesler
- Department of Ophthalmology/Ross Eye Institute and
- SUNY Eye Institute, Buffalo, New York 14203
- Research Service, Veterans Administration Western New York Healthcare System, Buffalo, New York 14215
| | - David M. Sherry
- Department of Cell Biology, Oklahoma Center for Neurosciences and Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73126, and
| | - Maureen Gannon
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Eduardo Solessio
- SUNY Eye Institute, Buffalo, New York 14203
- Department of Ophthalmology, Upstate Medical University, Syracuse, New York 13210
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute and
- Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, New York 14203
- SUNY Eye Institute, Buffalo, New York 14203
- CCSG Genetics Program, Roswell Park Cancer Institute, Buffalo, New York 14263
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Mao CA, Cho JH, Wang J, Gao Z, Pan P, Tsai WW, Frishman LJ, Klein WH. Reprogramming amacrine and photoreceptor progenitors into retinal ganglion cells by replacing Neurod1 with Atoh7. Development 2013; 140:541-51. [PMID: 23293286 DOI: 10.1242/dev.085886] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The specification of the seven retinal cell types from a common pool of retina progenitor cells (RPCs) involves complex interactions between the intrinsic program and the environment. The proneural basic helix-loop-helix (bHLH) transcriptional regulators are key components for the intrinsic programming of RPCs and are essential for the formation of the diverse retinal cell types. However, the extent to which an RPC can re-adjust its inherent program and the mechanisms through which the expression of a particular bHLH factor influences RPC fate is unclear. Previously, we have shown that Neurod1 inserted into the Atoh7 locus activates the retinal ganglion cell (RGC) program in Atoh7-expressing RPCs but not in Neurod1-expressing RPCs, suggesting that Atoh7-expressing RPCs are not able to adopt the cell fate determined by Neurod1, but rather are pre-programmed to produce RGCs. Here, we show that Neurod1-expressing RPCs, which are destined to produce amacrine and photoreceptor cells, can be re-programmed into RGCs when Atoh7 is inserted into the Neurod1 locus. These results suggest that Atoh7 acts dominantly to convert a RPC subpopulation not destined for an RGC fate to adopt that fate. Thus, Atoh7-expressing and Neurod1-expressing RPCs are intrinsically different in their behavior. Additionally, ChIP-Seq analysis identified an Atoh7-dependent enhancer within the intronic region of Nrxn3. The enhancer recognized and used Atoh7 in the developing retina to regulate expression of Nrxn3, but could be forced to use Neurod1 when placed in a different regulatory context. The results indicate that Atoh7 and Neurod1 activate distinct sets of genes in vivo, despite their common DNA-binding element.
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Affiliation(s)
- Chai-An Mao
- Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Sustained and Transient Contributions to the Rat Dark-Adapted Electroretinogram b-Wave. J Ophthalmol 2013; 2013:352917. [PMID: 23533706 PMCID: PMC3606803 DOI: 10.1155/2013/352917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/31/2013] [Indexed: 11/23/2022] Open
Abstract
The most dominant feature of the electroretinogram, the b-wave, is thought to reflect ON-bipolar cell responses. However, a number of studies suggest that the b-wave is made up of several components. We consider the composition of the rat b-wave by subtracting corneal negative components obtained using intravitreal application of pharmacological agents to remove postreceptoral responses. By analyzing the intensity-response characteristic of the PII across a range of fixed times during and after a light step, we find that the rat isolated PII has 2 components. The first has fast rise and decay characteristics with a low sensitivity to light. GABAc-mediated inhibitory pathways enhance this transient-ON component to manifest increased and deceased sensitivity to light at shorter (<160 ms) and longer times, respectively. The second component has slower temporal characteristics but is more sensitive to light. GABAc-mediated inhibition enhances this sustained-ON component but has little effect on its sensitivity to light. After stimulus offset, both transient and sustained components return to baseline, and a long latency sustained positive component becomes apparent. The light sensitivities of transient-ON and sustained-OFF components are consistent with activity arising from cone ON- and OFF-bipolar cells, whereas the sustained-ON component is likely to arise from rod bipolar cells.
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46
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Lei B. Rod-driven OFF pathway responses in the distal retina: dark-adapted flicker electroretinogram in mouse. PLoS One 2012; 7:e43856. [PMID: 22937111 PMCID: PMC3427186 DOI: 10.1371/journal.pone.0043856] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 07/30/2012] [Indexed: 01/10/2023] Open
Abstract
Purpose The rodent retina does not exhibit a positive OFF-response in the electroretinogram (ERG), which makes it difficult to evaluate its OFF-pathway functions in vivo. We studied the rod-driven OFF pathway responses by using a dark-adapted 10-Hz flicker ERG procedure in mouse. Materials and Methods Conventional ERGs and 10-Hz dark-adapted flicker ERGs were obtained in wild-type mice (C57BL/6), in mice with pure rod (cpfl1) or pure cone (rho−/−) function, and in nob1 mice which have a selective ON-pathway defect. To isolate the response from ON or OFF pathway, glutamate analogs 2-amino-4-phosphobutyric acid (APB, an ON pathway blocker) and cis-2, 3-piperidine-dicarboxylic acid (PDA, an OFF pathway blocker), were injected intravitreally. Results The amplitude-intensity profile of the dark-adapted 10-Hz flicker ERG in the wild-type mice exhibits two peaks at middle and high light intensities. The two peaks represent rod- and cone-driven responses respectively. In APB-treated C57BL/6 mice and in nob1 mice, the dark-adapted ERG b-waves were absent. However, both rod- and cone-driven OFF pathway responses were evident with flicker ERG recording. At middle light intensities that activate only rod system, the flicker ERG responses in saline-injected nob1 mice were similar to those in APB-injected cpfl1 mice and wild-type mice. These responses are sensitive to PDA. The amplitudes of these rod-driven OFF pathway responses were approximately 20% of the total rod-driven flicker ERG responses. Conclusion We demonstrate that the rod-OFF bipolar cell pathway is functional in the outer retina. The dark-adapted flicker ERG is practical for the evaluation of rod- and cone-driven responses, and the residual OFF pathway signals in subjects with ON pathway defects.
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Affiliation(s)
- Bo Lei
- Department of Ophthalmology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing, China.
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Cangiano L, Asteriti S, Cervetto L, Gargini C. The photovoltage of rods and cones in the dark-adapted mouse retina. J Physiol 2012; 590:3841-55. [PMID: 22641773 DOI: 10.1113/jphysiol.2011.226878] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Research on photoreceptors has led to important insights into how light signals are detected and processed in the outer retina. Most information about photoreceptor function, however, comes from lower vertebrates. The large majority of mammalian studies are based on suction pipette recordings of outer segment currents, a technique that doesn't allow examination of phenomena occurring downstream of phototransduction. Only a small number of whole-cell recordings have been made, mainly in the macaque. Due to the growing importance of the mouse in vision research, we have optimized a retinal slice preparation that allows the reliable collection of perforated-patch recordings from light responding rods and cones. Unexpectedly, the frequency of cone recordings was much higher than their numeric proportion of ∼3%. This allowed us to obtain direct functional evidence suggestive of rod–cone coupling in the mouse. Moreover, rods had considerably larger single photon responses than previously published for mammals (3.44 mV, SD 1.37, n = 19 at 24°C; 2.46 mV, SD 1.08, n = 10 at 36°C), and a relatively high signal/noise ratio (6.4, SD 1.8 at 24°C; 6.8, SD 2.8 at 36°C). Both findings imply a more favourable transmission at the rod–rod bipolar cell synapse. Accordingly, relatively few photoisomerizations were sufficient to elicit a half-maximal response (6.7, SD 2.7, n = 5 at 24°C; 10.6, SD 1.7, n = 3 at 36°C), leading to a narrow linear response range. Our study demonstrates new features of mammalian photoreceptors and opens the way for further investigations into photoreceptor function using retinas from mutant mouse models.
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Affiliation(s)
- Lorenzo Cangiano
- Department of Physiological Sciences, University of Pisa, Via San Zeno 31, I-56123 Pisa, Italy.
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48
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Gap-junctional coupling of mammalian rod photoreceptors and its effect on visual detection. J Neurosci 2012; 32:3552-62. [PMID: 22399777 DOI: 10.1523/jneurosci.2144-11.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The presence of gap junctions between rods in mammalian retina suggests a role for rod-rod coupling in human vision. Rod coupling is known to reduce response variability, but because junctional conductances are not known, the downstream effects on visual performance are uncertain. Here we assessed rod coupling in guinea pig retina by measuring: (1) the variability in responses to dim flashes, (2) Neurobiotin tracer coupling, and (3) junctional conductances. Results were consolidated into an electrical network model and a model of human psychophysical detection. Guinea pig rods form tracer pools of 1 to ∼20 rods, with junctional conductances averaging ∼350 pS. We calculate that coupling will reduce human dark-adapted sensitivity ∼10% by impairing the noise filtering of the synapse between rods and rod bipolar cells. However, coupling also mitigates synaptic saturation and is thus calculated to improve sensitivity when stimuli are spatially restricted or are superimposed over background illumination.
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Moskowitz A, Hansen RM, Eklund SE, Fulton AB. Electroretinographic (ERG) responses in pediatric patients using vigabatrin. Doc Ophthalmol 2012; 124:197-209. [PMID: 22426576 DOI: 10.1007/s10633-012-9320-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/02/2012] [Indexed: 11/30/2022]
Abstract
The antiepileptic drug vigabatrin is known to cause retinal and visual dysfunction, particularly visual field defects, in some patients. Electroretinography (ERG) is used in an attempt to identify adverse effects of vigabatrin (VGB) in patients who are not candidates for conventional perimetry. We report data from 114 pediatric patients taking VGB referred for clinical evaluation; median age at test was 22.9 (2.4 to 266.1) months, and median duration of VGB use was 9.7 (0.3 to 140.7) months. Twenty-seven of them were tested longitudinally (3 to 12 ERG tests). ERG responses to full-field stimuli were recorded in scotopic and photopic conditions, and results were compared to responses from healthy control subjects. We found that abnormalities of photoreceptor and post-receptor ERG responses are frequent in these young patients. The most frequently abnormal scotopic parameter was post-receptor sensitivity, log σ, derived from the b-wave stimulus-response function; the most frequently abnormal photopic parameter was the implicit time of the OFF response (d-wave) to a long (150 ms) flash. Abnormal 30-Hz flicker response amplitude, previously reported to be a predictor of visual field loss, occurred infrequently. For the group as a whole, none of the ERG parameters changed significantly with increasing duration of VGB use. Four of the 27 patients tested longitudinally showed systematic worsening of log σ with duration of VGB use. In a subset of patients who underwent perimetry (N = 39), there was no significant association of any ERG parameter with visual field defects. We cannot determine whether the ERG abnormalities we found were due solely to the effects of VGB. We caution against over-reliance on the ERG to monitor pediatric patients for VGB toxicity and recommend further development of a reliable test of peripheral vision to supplant ERG testing.
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Affiliation(s)
- Anne Moskowitz
- Department of Ophthalmology, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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50
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Herrmann R, Heflin SJ, Hammond T, Lee B, Wang J, Gainetdinov RR, Caron MG, Eggers ED, Frishman LJ, McCall MA, Arshavsky VY. Rod vision is controlled by dopamine-dependent sensitization of rod bipolar cells by GABA. Neuron 2011; 72:101-10. [PMID: 21982372 DOI: 10.1016/j.neuron.2011.07.030] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2011] [Indexed: 11/19/2022]
Abstract
Dark and light adaptation of retinal neurons allow our vision to operate over an enormous light intensity range. Here we report a mechanism that controls the light sensitivity and operational range of rod-driven bipolar cells that mediate dim-light vision. Our data indicate that the light responses of these cells are enhanced by sustained chloride currents via GABA(C) receptor channels. This sensitizing GABAergic input is controlled by dopamine D1 receptors, with horizontal cells serving as a plausible source of GABA release. Our findings expand the role of dopamine in vision from its well-established function of suppressing rod-driven signals in bright light to enhancing the same signals under dim illumination. They further reveal a role for GABA in sensitizing the circuitry for dim-light vision, thereby complementing GABA's traditional role in providing dynamic feedforward and feedback inhibition in the retina.
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Affiliation(s)
- Rolf Herrmann
- Albert Eye Research Institute, Duke University, Durham, NC 27710, USA
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