1
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Kumar D, Khan B, Okcay Y, Sis ÇÖ, Abdallah A, Murray F, Sharma A, Uemura M, Taliyan R, Heinbockel T, Rahman S, Goyal R. Dynamic endocannabinoid-mediated neuromodulation of retinal circadian circuitry. Ageing Res Rev 2024; 99:102401. [PMID: 38964508 DOI: 10.1016/j.arr.2024.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 06/05/2024] [Accepted: 06/28/2024] [Indexed: 07/06/2024]
Abstract
Circadian rhythms are biological rhythms that originate from the "master circadian clock," called the suprachiasmatic nucleus (SCN). SCN orchestrates the circadian rhythms using light as a chief zeitgeber, enabling humans to synchronize their daily physio-behavioral activities with the Earth's light-dark cycle. However, chronic/ irregular photic disturbances from the retina via the retinohypothalamic tract (RHT) can disrupt the amplitude and the expression of clock genes, such as the period circadian clock 2, causing circadian rhythm disruption (CRd) and associated neuropathologies. The present review discusses neuromodulation across the RHT originating from retinal photic inputs and modulation offered by endocannabinoids as a function of mitigation of the CRd and associated neuro-dysfunction. Literature indicates that cannabinoid agonists alleviate the SCN's ability to get entrained to light by modulating the activity of its chief neurotransmitter, i.e., γ-aminobutyric acid, thus preventing light-induced disruption of activity rhythms in laboratory animals. In the retina, endocannabinoid signaling modulates the overall gain of the retinal ganglion cells by regulating the membrane currents (Ca2+, K+, and Cl- channels) and glutamatergic neurotransmission of photoreceptors and bipolar cells. Additionally, endocannabinoids signalling also regulate the high-voltage-activated Ca2+ channels to mitigate the retinal ganglion cells and intrinsically photosensitive retinal ganglion cells-mediated glutamate release in the SCN, thus regulating the RHT-mediated light stimulation of SCN neurons to prevent excitotoxicity. As per the literature, cannabinoid receptors 1 and 2 are becoming newer targets in drug discovery paradigms, and the involvement of endocannabinoids in light-induced CRd through the RHT may possibly mitigate severe neuropathologies.
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Affiliation(s)
- Deepak Kumar
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
| | - Bareera Khan
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India
| | - Yagmur Okcay
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Çağıl Önal Sis
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Aya Abdallah
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Fiona Murray
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Ashish Sharma
- School of Medicine, Washington University, St. Louis, USA
| | - Maiko Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Rajeev Taliyan
- Department of Pharmacy, Birla Institute of Technology Science, Pilani, Rajasthan 333301, India.
| | - Thomas Heinbockel
- Howard University College of Medicine, Department of Anatomy, Washington, DC 20059, USA
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy South Dakota State University, Brookings, SD, USA.
| | - Rohit Goyal
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
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2
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Kalloniatis M, Loh CS, Acosta ML, Tomisich G, Zhu Y, Nivison‐smith L, Fletcher EL, Chua J, Sun D, Arunthavasothy N. Retinal amino acid neurochemistry in health and disease. Clin Exp Optom 2021; 96:310-32. [DOI: 10.1111/cxo.12015] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 07/01/2012] [Accepted: 07/17/2012] [Indexed: 12/25/2022] Open
Affiliation(s)
- Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Sydney, New South Wales, Australia,
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia,
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia,
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Chee Seang Loh
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Monica L Acosta
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Guido Tomisich
- Department of Optometry and Vision Science, The University of Melbourne, Parkville, Victoria, Australia,
| | - Yuan Zhu
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia,
| | - Lisa Nivison‐smith
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia,
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia,
| | - Jacqueline Chua
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Daniel Sun
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Niru Arunthavasothy
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
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3
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Keeley PW, Eglen SJ, Reese BE. From random to regular: Variation in the patterning of retinal mosaics. J Comp Neurol 2020; 528:2135-2160. [PMID: 32026463 DOI: 10.1002/cne.24880] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/07/2020] [Accepted: 01/31/2020] [Indexed: 12/23/2022]
Abstract
The various types of retinal neurons are each positioned at their respective depths within the retina where they are believed to be assembled as orderly mosaics, in which like-type neurons minimize proximity to one another. Two common statistical analyses for assessing the spatial properties of retinal mosaics include the nearest neighbor analysis, from which an index of their "regularity" is commonly calculated, and the density recovery profile derived from autocorrelation analysis, revealing the presence of an exclusion zone indicative of anti-clustering. While each of the spatial statistics derived from these analyses, the regularity index and the effective radius, can be useful in characterizing such properties of orderly retinal mosaics, they are rarely sufficient for conveying the natural variation in the self-spacing behavior of different types of retinal neurons and the extent to which that behavior generates uniform intercellular spacing across the mosaic. We consider the strengths and limitations of these and other spatial statistical analyses for assessing the patterning in retinal mosaics, highlighting a number of misconceptions and their frequent misuse. Rather than being diagnostic criteria for determining simply whether a population is "regular," they should be treated as descriptive statistics that convey variation in the factors that influence neuronal positioning. We subsequently apply multiple spatial statistics to the analysis of eight different mosaics in the mouse retina, demonstrating conspicuous variability in the degree of patterning present, from essentially random to notably regular. This variability in patterning has both a developmental as well as a functional significance, reflecting the rules governing the positioning of different types of neurons as the architecture of the retina is assembled, and the distinct mechanisms by which they regulate dendritic growth to generate their characteristic coverage and connectivity.
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Affiliation(s)
- Patrick W Keeley
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, California
| | - Stephen J Eglen
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - Benjamin E Reese
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, California.,Department of Psychological and Brain Sciences, University of California at Santa Barbara, Santa Barbara, California
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4
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Marc RE, Sigulinsky CL, Pfeiffer RL, Emrich D, Anderson JR, Jones BW. Heterocellular Coupling Between Amacrine Cells and Ganglion Cells. Front Neural Circuits 2018; 12:90. [PMID: 30487737 PMCID: PMC6247779 DOI: 10.3389/fncir.2018.00090] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/28/2018] [Indexed: 01/08/2023] Open
Abstract
All superclasses of retinal neurons, including bipolar cells (BCs), amacrine cells (ACs) and ganglion cells (GCs), display gap junctional coupling. However, coupling varies extensively by class. Heterocellular AC coupling is common in many mammalian GC classes. Yet, the topology and functions of coupling networks remains largely undefined. GCs are the least frequent superclass in the inner plexiform layer and the gap junctions mediating GC-to-AC coupling (GC::AC) are sparsely arrayed amidst large cohorts of homocellular AC::AC, BC::BC, GC::GC and heterocellular AC::BC gap junctions. Here, we report quantitative coupling for identified GCs in retinal connectome 1 (RC1), a high resolution (2 nm) transmission electron microscopy-based volume of rabbit retina. These reveal that most GC gap junctions in RC1 are suboptical. GC classes lack direct cross-class homocellular coupling with other GCs, despite opportunities via direct membrane contact, while OFF alpha GCs and transient ON directionally selective (DS) GCs are strongly coupled to distinct AC cohorts. Integrated small molecule immunocytochemistry identifies these as GABAergic ACs (γ+ ACs). Multi-hop synaptic queries of RC1 connectome further profile these coupled γ+ ACs. Notably, OFF alpha GCs couple to OFF γ+ ACs and transient ON DS GCs couple to ON γ+ ACs, including a large interstitial amacrine cell, revealing matched ON/OFF photic drive polarities within coupled networks. Furthermore, BC input to these γ+ ACs is tightly matched to the GCs with which they couple. Evaluation of the coupled versus inhibitory targets of the γ+ ACs reveals that in both ON and OFF coupled GC networks these ACs are presynaptic to GC classes that are different than the classes with which they couple. These heterocellular coupling patterns provide a potential mechanism for an excited GC to indirectly inhibit nearby GCs of different classes. Similarly, coupled γ+ ACs engaged in feedback networks can leverage the additional gain of BC synapses in shaping the signaling of downstream targets based on their own selective coupling with GCs. A consequence of coupling is intercellular fluxes of small molecules. GC::AC coupling involves primarily γ+ cells, likely resulting in GABA diffusion into GCs. Surveying GABA signatures in the GC layer across diverse species suggests the majority of vertebrate retinas engage in GC::γ+ AC coupling.
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Affiliation(s)
| | | | | | | | | | - Bryan William Jones
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, The University of Utah, Salt Lake City, UT, United States
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5
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Vinpocetine protects inner retinal neurons with functional NMDA glutamate receptors against retinal ischemia. Exp Eye Res 2018; 167:1-13. [DOI: 10.1016/j.exer.2017.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 07/31/2017] [Accepted: 10/08/2017] [Indexed: 11/21/2022]
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6
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Wilburn DB, Doty KA, Chouinard AJ, Eddy SL, Woodley SK, Houck LD, Feldhoff RC. Olfactory effects of a hypervariable multicomponent pheromone in the red-legged salamander, Plethodon shermani. PLoS One 2017; 12:e0174370. [PMID: 28358844 PMCID: PMC5373537 DOI: 10.1371/journal.pone.0174370] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 03/06/2017] [Indexed: 11/18/2022] Open
Abstract
Chemical communication via chemosensory signaling is an essential process for promoting and modifying reproductive behavior in many species. During courtship in plethodontid salamanders, males deliver a mixture of non-volatile proteinaceous pheromones that activate chemosensory neurons in the vomeronasal epithelium (VNE) and increase female receptivity. One component of this mixture, Plethodontid Modulating Factor (PMF), is a hypervariable pheromone expressed as more than 30 unique isoforms that differ between individual males-likely driven by co-evolution with female receptors to promote gene duplication and positive selection of the PMF gene complex. Courtship trials with females receiving different PMF isoform mixtures had variable effects on female mating receptivity, with only the most complex mixtures increasing receptivity, such that we believe that sufficient isoform diversity allows males to improve their reproductive success with any female in the mating population. The aim of this study was to test the effects of isoform variability on VNE neuron activation using the agmatine uptake assay. All isoform mixtures activated a similar number of neurons (>200% over background) except for a single purified PMF isoform (+17%). These data further support the hypothesis that PMF isoforms act synergistically in order to regulate female receptivity, and different putative mechanisms are discussed.
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Affiliation(s)
- Damien B. Wilburn
- Dept of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
- Dept of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Kari A. Doty
- Dept of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Adam J. Chouinard
- Dept of Zoology, Oregon State University, Corvallis, Oregon, United States of America
| | - Sarah L. Eddy
- Dept of Zoology, Oregon State University, Corvallis, Oregon, United States of America
| | - Sarah K. Woodley
- Dept of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, United States of America
| | - Lynne D. Houck
- Dept of Zoology, Oregon State University, Corvallis, Oregon, United States of America
| | - Richard C. Feldhoff
- Dept of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
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7
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Nivison-Smith L, Khoo P, Acosta ML, Kalloniatis M. Pre-treatment with vinpocetine protects against retinal ischemia. Exp Eye Res 2016; 154:126-138. [PMID: 27899287 DOI: 10.1016/j.exer.2016.11.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/17/2016] [Accepted: 11/22/2016] [Indexed: 01/15/2023]
Abstract
Vinpocetine has been shown to have beneficial effects for tissues of the central nervous system subjected to ischemia and other related metabolic insults. We recently showed vinpocetine promotes glucose availability, prevents unregulated cation channel permeability and regulates glial reactivity when present during retinal ischemia. Less is known however about the ability of vinpocetine to protect against future ischemic insults. This study explores the effect of vinpocetine when used as a pre-treatment in an ex vivo model for retinal ischemia using cation channel permeability of agmatine (AGB) combined with immunohistochemistry as a measure for cell functionality. We found that vinpocetine pre-treatment reduced cation channel permeability and apoptotic marker immunoreactivity in the GCL and increased parvalbumin immunoreactivity of inner retinal neurons in the inner nuclear layer following ischemic insult. Vinpocetine pre-treatment also reduced Müller cell reactivity following ischemic insults of up to 120 min compared to untreated controls. Many of vinpocetine's effects however were transient in nature suggesting the drug can protect retinal neurons against future ischemic damage but may have limited long-term applications.
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Affiliation(s)
- Lisa Nivison-Smith
- Centre for Eye Health, University of New South Wales, Sydney, 2052, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, 2052, Australia.
| | - Pauline Khoo
- School of Optometry and Vision Science, University of New South Wales, Sydney, 2052, Australia
| | - Monica L Acosta
- School of Optometry and Vision Science, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Sydney, 2052, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, 2052, Australia; School of Optometry and Vision Science, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand
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8
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Lauritzen JS, Sigulinsky CL, Anderson JR, Kalloniatis M, Nelson NT, Emrich DP, Rapp C, McCarthy N, Kerzner E, Meyer M, Jones BW, Marc RE. Rod-cone crossover connectome of mammalian bipolar cells. J Comp Neurol 2016; 527:87-116. [PMID: 27447117 PMCID: PMC5823792 DOI: 10.1002/cne.24084] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 06/08/2016] [Accepted: 06/30/2016] [Indexed: 11/11/2022]
Abstract
The basis of cross-suppression between rod and cone channels has long been an enigma. Using rabbit retinal connectome RC1, we show that all cone bipolar cell (BC) classes inhibit rod BCs via amacrine cell (AC) motifs (C1-6); that all cone BC classes are themselves inhibited by AC motifs (R1-5, R25) driven by rod BCs. A sparse symmetric AC motif (CR) is presynaptic and postsynaptic to both rod and cone BCs. ON cone BCs of all classes drive inhibition of rod BCs via motif C1 wide-field GABAergic ACs (γACs) and motif C2 narrow field glycinergic ON ACs (GACs). Each rod BC receives ≈10 crossover AC synapses and each ON cone BC can target ≈10 or more rod BCs via separate AC processes. OFF cone BCs mediate monosynaptic inhibition of rod BCs via motif C3 driven by OFF γACs and GACs and disynaptic inhibition via motifs C4 and C5 driven by OFF wide-field γACs and narrow-field GACs, respectively. Motifs C4 and C5 form halos of 60-100 inhibitory synapses on proximal dendrites of AI γACs. Rod BCs inhibit surrounding arrays of cone BCs through AII GAC networks that access ON and OFF cone BC patches via motifs R1, R2, R4, R5 and a unique ON AC motif R3 that collects rod BC inputs and targets ON cone BCs. Crossover synapses for motifs C1, C4, C5, and R3 are 3-4× larger than typical feedback synapses, which may be a signature for synaptic winner-take-all switches. J. Comp. Neurol. 527:87-116, 2019. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.
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Affiliation(s)
| | - Crystal L Sigulinsky
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - James R Anderson
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Michael Kalloniatis
- Department of Optometry and Vision Science and Centre for Eye Health, University of New South Wales, Sydney, Australia
| | - Noah T Nelson
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Daniel P Emrich
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Christopher Rapp
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Nicholas McCarthy
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Ethan Kerzner
- Scientific Computing and Imaging Institute, University of Utah School of Computing, Salt Lake City Utah, USA
| | - Miriah Meyer
- Scientific Computing and Imaging Institute, University of Utah School of Computing, Salt Lake City Utah, USA
| | - Bryan W Jones
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Robert E Marc
- Department of Ophthalmology, John A. Moran Vision Institute, University of Utah School of Medicine, Salt Lake City, Utah, USA
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9
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Jones BW, Pfeiffer RL, Ferrell WD, Watt CB, Marmor M, Marc RE. Retinal remodeling in human retinitis pigmentosa. Exp Eye Res 2016; 150:149-65. [PMID: 27020758 DOI: 10.1016/j.exer.2016.03.018] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 02/23/2016] [Accepted: 03/18/2016] [Indexed: 12/11/2022]
Abstract
Retinitis Pigmentosa (RP) in the human is a progressive, currently irreversible neural degenerative disease usually caused by gene defects that disrupt the function or architecture of the photoreceptors. While RP can initially be a disease of photoreceptors, there is increasing evidence that the inner retina becomes progressively disorganized as the outer retina degenerates. These alterations have been extensively described in animal models, but remodeling in humans has not been as well characterized. This study, using computational molecular phenotyping (CMP) seeks to advance our understanding of the retinal remodeling process in humans. We describe cone mediated preservation of overall topology, retinal reprogramming in the earliest stages of the disease in retinal bipolar cells, and alterations in both small molecule and protein signatures of neurons and glia. Furthermore, while Müller glia appear to be some of the last cells left in the degenerate retina, they are also one of the first cell classes in the neural retina to respond to stress which may reveal mechanisms related to remodeling and cell death in other retinal cell classes. Also fundamentally important is the finding that retinal network topologies are altered. Our results suggest interventions that presume substantial preservation of the neural retina will likely fail in late stages of the disease. Even early intervention offers no guarantee that the interventions will be immune to progressive remodeling. Fundamental work in the biology and mechanisms of disease progression are needed to support vision rescue strategies.
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Affiliation(s)
- B W Jones
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA.
| | - R L Pfeiffer
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
| | - W D Ferrell
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
| | - C B Watt
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
| | - M Marmor
- Dept. Ophthalmology, Stanford University, USA
| | - R E Marc
- Dept. Ophthalmology, Moran Eye Center, University of Utah, USA
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10
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Kalloniatis M, Nivison-Smith L, Chua J, Acosta ML, Fletcher EL. Using the rd1 mouse to understand functional and anatomical retinal remodelling and treatment implications in retinitis pigmentosa: A review. Exp Eye Res 2015; 150:106-21. [PMID: 26521764 DOI: 10.1016/j.exer.2015.10.019] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 12/31/2022]
Abstract
Retinitis Pigmentosa (RP) reflects a range of inherited retinal disorders which involve photoreceptor degeneration and retinal pigmented epithelium dysfunction. Despite the multitude of genetic mutations being associated with the RP phenotype, the clinical and functional manifestations of the disease remain the same: nyctalopia, visual field constriction (tunnel vision), photopsias and pigment proliferation. In this review, we describe the typical clinical phenotype of human RP and review the anatomical and functional remodelling which occurs in RP determined from studies in the rd/rd (rd1) mouse. We also review studies that report a slowing down or show an acceleration of retinal degeneration and finally we provide insights on the impact retinal remodelling may have in vision restoration strategies.
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Affiliation(s)
- M Kalloniatis
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia; School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia; School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia.
| | - L Nivison-Smith
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia; School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - J Chua
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - M L Acosta
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - E L Fletcher
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
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11
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Nivison-Smith L, O'Brien BJ, Truong M, Guo CX, Kalloniatis M, Acosta ML. Vinpocetine modulates metabolic activity and function during retinal ischemia. Am J Physiol Cell Physiol 2015; 308:C737-49. [PMID: 25696811 DOI: 10.1152/ajpcell.00291.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 02/17/2015] [Indexed: 12/18/2022]
Abstract
Vinpocetine protects against a range of degenerative conditions and insults of the central nervous system via multiple modes of action. Little is known, however, of its effects on metabolism. This may be highly relevant, as vinpocetine is highly protective against ischemia, a process that inhibits normal metabolic function. This study uses the ischemic retina as a model to characterize vinpocetine's effects on metabolism. Vinpocetine reduced the metabolic demand of the retina following ex vivo hypoxia and ischemia to normal levels based on lactate dehydrogenase activity. Vinpocetine delivered similar effects in an in vivo model of retinal ischemia-reperfusion, possibly through increasing glucose availability. Vinpocetine's effects on glucose also appeared to improve glutamate homeostasis in ischemic Müller cells. Other actions of vinpocetine following ischemia-reperfusion, such as reduced cell death and improved retinal function, were possibly a combination of the drug's actions on metabolism and other retinal pathways. Vinpocetine's metabolic effects appeared independent of its other known actions in ischemia, as it recovered retinal function in a separate metabolic model where the glutamate-to-glutamine metabolic pathway was inhibited in Müller cells. The results of this study indicate that vinpocetine mediates ischemic damage partly through altered metabolism and has potential beneficial effects as a treatment for ischemia of neuronal tissues.
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Affiliation(s)
- Lisa Nivison-Smith
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Brendan J O'Brien
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Mai Truong
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Cindy X Guo
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Michael Kalloniatis
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia; Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; Centre for Eye Health, University of New South Wales, Sydney, Australia; and
| | - Monica L Acosta
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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12
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Nivison-Smith L, Sun D, Fletcher EL, Marc RE, Kalloniatis M. Mapping kainate activation of inner neurons in the rat retina. J Comp Neurol 2014; 521:2416-38. [PMID: 23348566 DOI: 10.1002/cne.23305] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/06/2012] [Accepted: 01/17/2013] [Indexed: 11/10/2022]
Abstract
Kainate receptors mediate fast, excitatory synaptic transmission for a range of inner neurons in the mammalian retina. However, allocation of functional kainate receptors to known cell types and their sensitivity remains unresolved. Using the cation channel probe 1-amino-4-guanidobutane agmatine (AGB), we investigated kainate sensitivity of neurochemically identified cell populations within the structurally intact rat retina. Most inner retinal neuron populations responded to kainate in a concentration-dependent manner. OFF cone bipolar cells demonstrated the highest sensitivity of all inner neurons to kainate. Immunocytochemical localization of AGB and macromolecular markers confirmed that type 2 bipolar cells were part of this kainate-sensitive population. The majority of amacrine (ACs) and ganglion cells (GCs) showed kainate responses with different sensitivities between major neurochemical classes (γ-aminobutyric acid [GABA]/glycine ACs > glycine ACs > GABA ACs; glutamate [Glu]/weakly GABA GCs > Glu GCs). Conventional and displaced cholinergic ACs were highly responsive to kainate, whereas dopaminergic ACs do not appear to express functional kainate receptors. These findings further contribute to our understanding of neuronal networks in complex multicellular tissues.
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Affiliation(s)
- Lisa Nivison-Smith
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, 2052, Australia
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13
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Vinpocetine regulates cation channel permeability of inner retinal neurons in the ischaemic retina. Neurochem Int 2014; 66:1-14. [DOI: 10.1016/j.neuint.2014.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/09/2013] [Accepted: 01/04/2014] [Indexed: 11/23/2022]
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Lauritzen JS, Anderson JR, Jones BW, Watt CB, Mohammed S, Hoang JV, Marc RE. ON cone bipolar cell axonal synapses in the OFF inner plexiform layer of the rabbit retina. J Comp Neurol 2013; 521:977-1000. [PMID: 23042441 DOI: 10.1002/cne.23244] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 10/03/2012] [Accepted: 10/04/2012] [Indexed: 11/07/2022]
Abstract
Analysis of the rabbit retinal connectome RC1 reveals that the division between the ON and the OFF inner plexiform layer (IPL) is not structurally absolute. ON cone bipolar cells make noncanonical axonal synapses onto specific targets and receive amacrine cell synapses in the nominal OFF layer, creating novel motifs, including inhibitory crossover networks. Automated transmission electron microscopic imaging, molecular tagging, tracing, and rendering of ~400 bipolar cells reveals axonal ribbons in 36% of ON cone bipolar cells, throughout the OFF IPL. The targets include γ-aminobutyrate (GABA)-positive amacrine cells (γACs), glycine-positive amacrine cells (GACs), and ganglion cells. Most ON cone bipolar cell axonal contacts target GACs driven by OFF cone bipolar cells, forming new architectures for generating ON-OFF amacrine cells. Many of these ON-OFF GACs target ON cone bipolar cell axons, ON γACs, and/or ON-OFF ganglion cells, representing widespread mechanisms for OFF to ON crossover inhibition. Other targets include OFF γACs presynaptic to OFF bipolar cells, forming γAC-mediated crossover motifs. ON cone bipolar cell axonal ribbons drive bistratified ON-OFF ganglion cells in the OFF layer and provide ON drive to polarity-appropriate targets such as bistratified diving ganglion cells (bsdGCs). The targeting precision of ON cone bipolar cell axonal synapses shows that this drive incidence is necessarily a joint distribution of cone bipolar cell axonal frequency and target cell trajectories through a given volume of the OFF layer. Such joint distribution sampling is likely common when targets are sparser than sources and when sources are coupled, as are ON cone bipolar cells.
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Affiliation(s)
- J Scott Lauritzen
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah 84132, USA
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15
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Mapping cation entry in photoreceptors and inner retinal neurons during early degeneration in the P23H-3 rat retina. Vis Neurosci 2013; 30:65-75. [PMID: 23557623 DOI: 10.1017/s0952523813000047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The proline-23-histidine line 3 (P23H-3) transgenic rat carries a human opsin gene mutation leading to progressive photoreceptor loss characteristic of human autosomal dominant retinitis pigmentosa. The aim of the present study was to evaluate neurochemical modifications in the P23H-3 retina as a function of development and degeneration. Specifically, we investigated the ion channel permeability of photoreceptors by tracking an organic cation, agmatine (1-amino-4-guanidobutane, AGB), which permeates through nonspecific cation channels. We also investigated the activity of ionotropic glutamate receptors in distinct populations of bipolar, amacrine, and ganglion cells using AGB tracking in combination with macromolecular markers. We found elevated cation channel permeation in photoreceptors as early as postnatal day 12 (P12) suggesting that AGB labeling is an early indicator of impending photoreceptor degeneration. However, bipolar, amacrine, or ganglion cells displayed normal responses secondary to ionotropic glutamate receptor activation even at P138 when about one half of the photoreceptor layer was lost and apoptosis and gliosis were observed. These results suggest that possible therapeutic windows as downstream neurons in inner retina appear to retain normal function with regard to AGB permeation when photoreceptors are significantly reduced but not lost.
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Nivison-Smith L, Collin SP, Zhu Y, Ready S, Acosta ML, Hunt DM, Potter IC, Kalloniatis M. Retinal amino acid neurochemistry of the southern hemisphere lamprey, Geotria australis. PLoS One 2013; 8:e58406. [PMID: 23516473 PMCID: PMC3596384 DOI: 10.1371/journal.pone.0058406] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 02/04/2013] [Indexed: 01/01/2023] Open
Abstract
Lampreys are one of the two surviving groups of the agnathan (jawless) stages in vertebrate evolution and are thus ideal candidates for elucidating the evolution of visual systems. This study investigated the retinal amino acid neurochemistry of the southern hemisphere lamprey Geotria australis during the downstream migration of the young, recently-metamorphosed juveniles to the sea and during the upstream migration of the fully-grown and sexually-maturing adults to their spawning areas. Glutamate and taurine were distributed throughout the retina, whilst GABA and glycine were confined to neurons of the inner retina matching patterns seen in most other vertebrates. Glutamine and aspartate immunoreactivity was closely matched to Müller cell morphology. Between the migratory phases, few differences were observed in the distribution of major neurotransmitters i.e. glutamate, GABA and glycine, but changes in amino acids associated with retinal metabolism i.e. glutamine and aspartate, were evident. Taurine immunoreactivity was mostly conserved between migrant stages, consistent with its role in primary cell functions such as osmoregulation. Further investigation of glutamate signalling using the probe agmatine (AGB) to map cation channel permeability revealed entry of AGB into photoreceptors and horizontal cells followed by accumulation in inner retinal neurons. Similarities in AGB profiles between upstream and downstream migrant of G. australis confirmed the conservation of glutamate neurotransmission. Finally, calcium binding proteins, calbindin and calretinin were localized to the inner retina whilst recoverin was localized to photoreceptors. Overall, conservation of major amino acid neurotransmitters and calcium-associated proteins in the lamprey retina confirms these elements as essential features of the vertebrate visual system. On the other hand, metabolic elements of the retina such as neurotransmitter precursor amino acids and Müller cells are more sensitive to environmental changes associated with migration.
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Affiliation(s)
- Lisa Nivison-Smith
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Shaun P. Collin
- School of Animal Biology and the University of Western Australia Oceans Institute, University of Western Australia, Crawley, Western Australia, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Yuan Zhu
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Sarah Ready
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Monica L. Acosta
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - David M. Hunt
- School of Animal Biology and the University of Western Australia Oceans Institute, University of Western Australia, Crawley, Western Australia, Australia
| | - Ian C. Potter
- School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, Western Australia, Australia
| | - Michael Kalloniatis
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
- Centre for Eye Health, University of New South Wales, Sydney, New South Wales, Australia
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17
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Seiler MJ, Jones BW, Aramant RB, Yang PB, Keirstead HS, Marc RE. Computational molecular phenotyping of retinal sheet transplants to rats with retinal degeneration. Eur J Neurosci 2012; 35:1692-704. [PMID: 22594836 DOI: 10.1111/j.1460-9568.2012.08078.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Retinal progenitor sheet transplants have been shown to extend neuronal processes into a degenerating host retina and to restore visual responses in the brain. The aim of this study was to identify cells involved in transplant signals to retinal degenerate hosts using computational molecular phenotyping (CMP). S334ter line 3 rats received fetal retinal sheet transplants at the age of 24-40 days. Donor tissues were incubated with slow-releasing microspheres containing brain-derived neurotrophic factor or glial cell-derived neurotrophic factor. Up to 265 days after surgery, eyes of selected rats were vibratome-sectioned through the transplant area (some slices stained for donor marker human placental alkaline phosphatase), dehydrated and embedded in Eponate, sectioned into serial ultrathin datasets and probed for rhodopsin, cone opsin, CRALBP (cellular retinaldehyde binding protein), l-glutamate, l-glutamine, glutathione, glycine, taurine, γ-aminobutyric acid (GABA) and DAPI (4',6-diamidino-2-phenylindole). In large transplant areas, photoreceptor outer segments in contact with host retinal pigment epithelium revealed rod and cone opsin immunoreactivity whereas no such staining was found in the degenerate host retina. Transplant photoreceptor layers contained high taurine levels. Glutamate levels in the transplants were higher than in the host retina whereas GABA levels were similar. The transplant inner nuclear layer showed some loss of neurons, but amacrine cells and horizontal cells were not reduced. In many areas, glial hypertrophy between the host and transplant was absent and host and transplant neuropil appeared to intermingle. CMP data indicate that horizontal cells and both glycinergic and GABAergic amacrine cells are involved in a novel circuit between transplant and host, generating alternative signal pathways between transplant and degenerating host retina.
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Affiliation(s)
- M J Seiler
- Anatomy & Neurobiol/Reeve-Irvine Research Center, UC Irvine, Irvine, CA 92697-4265, USA
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18
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de Souza CF, Kalloniatis M, Polkinghorne PJ, McGhee CN, Acosta ML. Functional and anatomical remodeling in human retinal detachment. Exp Eye Res 2012; 97:73-89. [DOI: 10.1016/j.exer.2012.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 02/01/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
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Wirsig-Wiechmann CR, Colvard J, Aston CE, Dighe R, Houck LD, Feldhoff PW, Feldhoff RC. Gonadotropin-Releasing Hormone Modulates Vomeronasal Neuron Response to Male Salamander Pheromone. J Exp Neurosci 2012. [DOI: 10.4137/jen.s8414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Electrophysiological studies have shown that gonadotropin-releasing hormone (GnRH) modifies chemosensory neurons responses to odors. We have previously demonstrated that male Plethodon shermani pheromone stimulates vomeronasal neurons in the female conspecific. In the present study we used agmatine uptake as a relative measure of the effects of GnRH on this pheromone-induced neural activation of vomeronasal neurons. Whole male pheromone extract containing 3 millimolar agmatine with or without 10 micromolar GnRH was applied to the nasolabial groove of female salamanders for 45 minutes. Immunocytochemical procedures were conducted to visualize and quantify relative agmatine uptake as measured by labeling density of activated vomeronasal neurons. The relative number of labeled neurons did not differ between the two groups: pheromone alone or pheromone-GnRH. However, vomeronasal neurons exposed to pheromone-GnRH collectively demonstrated higher labeling intensity, as a percentage above background (75%) as compared with neurons exposed to pheromone alone (63%, P < 0.018). Since the labeling intensity of agmatine within neurons signifies the relative activity levels of the neurons, these results suggest that GnRH increases the response of female vomeronasal neurons to male pheromone.
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Affiliation(s)
- Celeste R. Wirsig-Wiechmann
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 S.L. Young Boulevard, Oklahoma City, OK 73104
| | - Justin Colvard
- Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, New Orleans, LA 70112
| | - Christopher E. Aston
- Department of Pediatrics, University of Oklahoma Health Sciences Center, 1122 N.E. 13th Street, Oklahoma City, OK 73117
| | - Radhika Dighe
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 S.L. Young Boulevard, Oklahoma City, OK 73104
| | - Lynne D. Houck
- Department of Zoology, Oregon State University, Corvallis, Or 97331-2914
| | - Pamela W. Feldhoff
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, KY 40292
| | - Richard C. Feldhoff
- Department of Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, Louisville, KY 40292
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20
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de Souza CF, Kalloniatis M, Polkinghorne PJ, McGhee CN, Acosta ML. Functional activation of glutamate ionotropic receptors in the human peripheral retina. Exp Eye Res 2012; 94:71-84. [DOI: 10.1016/j.exer.2011.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 10/22/2011] [Accepted: 11/15/2011] [Indexed: 10/15/2022]
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Jones BW, Kondo M, Terasaki H, Watt CB, Rapp K, Anderson J, Lin Y, Shaw MV, Yang JH, Marc RE. Retinal remodeling in the Tg P347L rabbit, a large-eye model of retinal degeneration. J Comp Neurol 2011; 519:2713-33. [PMID: 21681749 DOI: 10.1002/cne.22703] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Retinitis pigmentosa (RP) is an inherited blinding disease characterized by progressive loss of retinal photoreceptors. There are numerous rodent models of retinal degeneration, but most are poor platforms for interventions that will translate into clinical practice. The rabbit possesses a number of desirable qualities for a model of retinal disease including a large eye and an existing and substantial knowledge base in retinal circuitry, anatomy, and ophthalmology. We have analyzed degeneration, remodeling, and reprogramming in a rabbit model of retinal degeneration, expressing a rhodopsin proline 347 to leucine transgene in a TgP347L rabbit as a powerful model to study the pathophysiology and treatment of retinal degeneration. We show that disease progression in the TgP347L rabbit closely tracks human cone-sparing RP, including the cone-associated preservation of bipolar cell signaling and triggering of reprogramming. The relatively fast disease progression makes the TgP347L rabbit an excellent model for gene therapy, cell biological intervention, progenitor cell transplantation, surgical interventions, and bionic prosthetic studies.
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Affiliation(s)
- B W Jones
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah 84132, USA.
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22
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Chen YP, Chiao CC. Functional expression of ionotropic glutamate receptors in the rabbit retinal ganglion cells. Brain Res 2011; 1427:10-22. [PMID: 22071563 DOI: 10.1016/j.brainres.2011.10.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Revised: 09/15/2011] [Accepted: 10/09/2011] [Indexed: 11/24/2022]
Abstract
It has been known that retinal ganglion cells (RGCs) with distinct morphologies have different physiological properties. It was hypothesized that different functions of RGCs may in part result from various expressions of N-methyl-d-aspartate (NMDA), α-amino-3-hydroxyl-5-methyl-isoxazole-4-propinoic acid (AMPA), and kainic acid (KA) receptors on their dendrites. In the present study, we aimed to characterize the functional expression of AMPA and NMDA receptors of morphologically identified RGCs in the wholemount rabbit retina. The agmatine (AGB) activation assay was used to reveal functional expression of ionotropic glutamate receptors after the RGCs were targeted by injecting Neurobiotin. To examine the excitability of these glutamate receptors in an agonist specific manner, the lower concentrations of AMPA (2 μM) and NMDA (100 μM) were chosen to examine G7 (ON-OFF direction selective ganglion cells) and G11 (alpha ganglion cells) types of RGCs. We found that less than 40% of G7 type RGCs had salient AGB activation when incubated with 2 μM AMPA or 100 μM NMDA. The G11 type RGCs also showed similar activation frequencies, except that all of the OFF subtype examined had no AGB permeation under the same AMPA concentration. These results suggest that RGCs with large somata (G7 and G11 types) may express various heterogeneous functional ionotropic glutamate receptors, thus in part rendering their functional diversity.
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Affiliation(s)
- Yin-Peng Chen
- Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 30013, Taiwan
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23
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Chua J, Fletcher EL, Kalloniatis M. Functional remodeling of glutamate receptors by inner retinal neurons occurs from an early stage of retinal degeneration. J Comp Neurol 2009; 514:473-91. [PMID: 19350664 DOI: 10.1002/cne.22029] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Retinitis pigmentosa reflects a family of diseases that result in retinal photoreceptor death and functional blindness. The natural course of retinal changes secondary to photoreceptor degeneration involves anatomical remodeling (cell process alterations and soma displacement) and neurochemical remodeling. Anatomical remodeling predominantly occurs late in the disease process and cannot explain the significant visual deficits that occur very early in the disease process. Neurochemical remodeling includes modified glutamate receptor disposition and altered responses secondary to functional activation of glutamate receptors. We investigated the neurochemical remodeling of retinal neurons in the rd/rd (rd1) mouse retina by tracking the functional activation of glutamate receptors with a cation probe, agmatine. We provide evidence that bipolar cells and amacrine cells undergo selective remodeling of glutamate receptors during the early phases of retinal degeneration. These early neurochemical changes in the rd/rd mouse retina include the expression of aberrant functional ionotropic glutamate receptors on the cone ON bipolar cells from postnatal day 15 (P15), poor functional activation of metabotropic glutamate receptors on both rod and cone ON bipolar cells throughout development/degeneration, and poor functional activation of N-methyl-D-aspartate receptors on amacrine cells from P15. Our results suggest that major neurochemical remodeling occurs prior to anatomical remodeling, and likely accounts for the early visual deficits in the rd/rd mouse retina.
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Affiliation(s)
- Jacqueline Chua
- Department of Optometry and Vision Science, University of Auckland, Private Bag 92010, Auckland, New Zealand
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24
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Du Y, Hirooka K, Miyamoto O, Itano T, Tokuda M, Shiraga F. Both amacrine and bipolar cells release glutamate in the rat retina after ischemia/reperfusion insult in vitro. Curr Eye Res 2008; 33:782-8. [PMID: 18798081 DOI: 10.1080/02713680802334600] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE To investigate which cells in the inner nuclear layer release glutamate after exposure through the use of a model mimicking rat retina ischemia/reperfusion induced by glucose/oxygen deprivation in vitro. METHODS An in vitro retinal ischemia model was used to monitor the release of glutamate by staining with diaminobenzidine hydrochloride. Immunocytochemistry was used to identify the cells releasing glutamate during ischemic/reperfusion injury. RESULTS On immunocytochemistry, double-labeling of some amacrine and bipolar cells was observed, with somata being stained blue by GABA and two portions of the processes labeled brown due to glutamate reactivity. Some somata of amacrine cells were double-labeled with calbindin, while horizontal cells were single-labeled with calbindin. CONCLUSIONS During ischemia/reperfusion injury in vitro, both amacrine and bipolar cells release glutamate. These results may be related to the patterns of apoptotic cell death seen in the inner retina.
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Affiliation(s)
- Yinghua Du
- Department of Ophthalmology, Kagawa University Faculty of Medicine, Kagawa, Japan
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25
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Hu RG, Lim J, Donaldson PJ, Kalloniatis M. Characterization of the cystine/glutamate transporter in the outer plexiform layer of the vertebrate retina. Eur J Neurosci 2008; 28:1491-502. [DOI: 10.1111/j.1460-9568.2008.06435.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Mobley AS, Michel WC, Lucero MT. Odorant responsiveness of squid olfactory receptor neurons. Anat Rec (Hoboken) 2008; 291:763-74. [PMID: 18484602 DOI: 10.1002/ar.20704] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In the olfactory organ of the squid, Lolliguncula brevis there are five morphological types of olfactory receptor neurons (ORNs). Previous work to characterize odor sensitivity of squid ORNs was performed on only two of the five types in dissociated primary cell cultures. Here, we sought to establish the odorant responsiveness of all five types. We exposed live squid or intact olfactory organs to excitatory odors plus the activity marker, agmatine (AGB), an arginine derivative that enters cells through nonselective cation channels. An antibody against AGB was used to identify odorant-activated neurons. We were able to determine the ORN types of AGB-labeled cells based on their location in the epithelium, morphology and immunolabeling by a set of metabolites: arginine, aspartate, glutamate, glycine, and glutathione. Of 389 neurons identified from metabolite-labeled tissue, 3% were type 1, 32% type 2, 33% type 3, 15% type 4, and 17% type 5. Each ORN type had different odorant specificity with type 3 cells showing the highest percentages of odorant-stimulated AGB labeling. Type 1 cells were rare and none of the identified type 1 cells responded to the tested odorants, which included glutamate, alanine and AGB. Glutamate is a behaviorally attractive odorant and elicited AGB labeling in types 2 and 3. Glutamate-activated AGB labeling was significantly reduced in the presence of the adenylate cyclase inhibitor, SQ22536 (80 microM). These data suggest that the five ORN types differ in their relative abundance and odor responsiveness and that the adenylate cyclase pathway is involved in squid olfactory transduction.
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27
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Hartwick ATE, Hamilton CM, Baldridge WH. Glutamatergic calcium dynamics and deregulation of rat retinal ganglion cells. J Physiol 2008; 586:3425-46. [PMID: 18483069 DOI: 10.1113/jphysiol.2008.154609] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A rise in intracellular calcium levels ([Ca(2+)](i)) is a key trigger for the lethal effects of the excitatory neurotransmitter glutamate in various central neurons, but a consensus has not been reached on the pathways that mediate glutamate-dependent increases of [Ca(2+)](i) in retinal ganglion cells (RGCs). Using Ca(2+) imaging techniques we demonstrated that, in the absence of external Mg(2+), the Ca(2+) signal evoked by glutamate was predominantly mediated by NMDA-type glutamate receptors (NMDA-Rs) in immunopanned RGCs isolated from neonatal or adult rats. Voltage-gated Ca(2+) channels and AMPA/kainate-Rs contributed a smaller portion of the Ca(2+) response at saturating concentrations of glutamate. Consistent with NMDA-R involvement, extracellular Mg(2+) inhibited RGC glutamate responses, while glycine had a potentiating effect. With Mg(2+) present externally, the effect of AMPA/kainate-R antagonists was enhanced and both NMDA- and AMPA/kainate-R antagonists greatly reduced the glutamate-induced increases of RGC [Ca(2+)](i). This finding indicates that the primary contribution of AMPA/kainate-Rs to RGC glutamatergic Ca(2+) dynamics is through the depolarization-dependent relief of the Mg(2+) block of NMDA-R channels. The effect of glutamate receptor antagonists on glutamatergic Ca(2+) signals from RGCs in adult rat retinal wholemounts yielded results similar to those obtained using immunopanned RGCs. Additional experiments on isolated RGCs revealed that during a 1 h glutamate (10-1000 microm) exposure, 18-28% of RGCs exhibited delayed Ca(2+) deregulation (DCD) and the RGCs that underwent DCD were positive for the death marker annexin V. RGCs with larger glutamate-evoked Ca(2+) signals were more likely to undergo DCD, and NMDA-R blockade significantly reduced the occurrence of DCD. Identifying the mechanisms underlying RGC excitotoxicity aids in our understanding of the pathophysiology of retinal ischaemia, and this work establishes a major role for NMDA-R-mediated increases in [Ca(2+)](i) in glutamate-related RGC death.
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Affiliation(s)
- Andrew T E Hartwick
- Retina and Optic Nerve Research Laboratory, Department of Anatomy & Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada
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28
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Sun D, Bui BV, Vingrys AJ, Kalloniatis M. Alterations in photoreceptor-bipolar cell signaling following ischemia/reperfusion in the rat retina. J Comp Neurol 2008; 505:131-46. [PMID: 17729268 DOI: 10.1002/cne.21470] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Studies of retinal ischemia/reperfusion indicate a disparity between the anatomical and functional results; while a large number of rod bipolar cells remain postischemia, there is a significant reduction in the amplitude of the scotopic b-wave of the electroretinogram (ERG). We investigated the alterations in photoreceptor-bipolar cell signaling following ischemia/reperfusion and suggest a mechanism for the decrease in b-wave amplitude. A cation channel probe (agmatine, 1-amino-4-guanidobutane, AGB) was used to assess cellular ion channel activity in neurochemically identified cells secondary to endogenous glutamate release or pharmacological manipulations. By applying the "neurochemical truth point" principle (Sun et al. [2007a] J Comp Neurol, this issue), we have been able to confirm the loss of specific subpopulations of neurons. ERG was used to assess gross retinal function, with parameters of the ERG model providing insight into changes in the phototransduction cascade and sensitivity of postreceptoral glutamate receptors. Following ischemia/reperfusion, rod bipolar cells maintained 2-amino-4-phosphonobutyric acid-responsive metabotropic glutamate receptors and displayed no change in sensitivity to flashes of light as assessed by ERG. Therefore, the loss in b-wave amplitude is likely due to alterations in photoreceptoral glutamate release detected as a change in postsynaptic AGB permeation into rod bipolar cells. Bipolar cell to amacrine cell signaling was also altered. The robust AGB entry into cholinergic amacrine cells was virtually absent in retinas that had undergone ischemia/reperfusion but remained in the AII amacrine cells. Such results suggest a loss of glutamate receptors and/or a change in receptor subunit expression in subpopulations of inner retinal neurons. Although many cells retain their characteristic neurochemical labeling following ischemia/reperfusion, caution should be used when assuming cells participate in functional retinal circuits based solely on the persistence of neurochemical labeling.
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Affiliation(s)
- Daniel Sun
- Department of Optometry and Vision Science, University of Auckland, New Zealand
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29
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Sun D, Vingrys AJ, Kalloniatis M. Metabolic and functional profiling of the ischemic/reperfused rat retina. J Comp Neurol 2008; 505:114-30. [PMID: 17729266 DOI: 10.1002/cne.21481] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We quantitatively tracked the recovery in amino acid labeling and cation channel functionality within distinct retinal elements for up to 2 weeks after an ischemic insult. Pattern recognition analysis of multiple amino acid and agmatine (a cation channel probe; 1-amino-4-guanidobutane; AGB) immunocytochemical patterns was used to classify all neural elements within the retina. This classification was spatially complete and with single-cell resolution. By 48 hours of reperfusion the amino acid labeling pattern of virtually all cell populations had returned to near preischemic levels, with the exception of glutamine and alanine levels, which remained significantly higher in many cell populations. Classification resulted in a total of 18 statistically separable theme classes (including neurons, glia, and extraretinal classes), a reduction of 10 theme classes from the normal retina (Sun et al. [ 2007a, b] J Comp Neurol, this issue). In addition to the known selective losses of amacrine cell types within the inner nuclear layer, we now demonstrate a selective loss of theme classes representing cone bipolar cells within the bipolar cell population. While there was a recovery in the amino acid labeling pattern, there were persistent cation channel gating anomalies (as reflected by AGB labeling) within several theme classes, including the theme class representing all the remaining rod bipolar cells, suggesting aberrant neuronal function secondary to metabolic insult.
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Affiliation(s)
- Daniel Sun
- Department of Optometry and Vision Science, University of Auckland, New Zealand
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30
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Edwards JG, Greig A, Sakata Y, Elkin D, Michel WC. Cholinergic innervation of the zebrafish olfactory bulb. J Comp Neurol 2008; 504:631-45. [PMID: 17722029 DOI: 10.1002/cne.21480] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A number of fish species receive forebrain cholinergic input but two recent reports failed to find evidence of cholinergic cell bodies or fibers in the olfactory bulbs (OBs) of zebrafish. In the current study we sought to confirm these findings by examining the OBs of adult zebrafish for choline acetyltransferase (ChAT) immunoreactivity. We observed a diffuse network of varicose ChAT-positive fibers associated with the nervus terminalis ganglion innervating the mitral cell/glomerular layer (MC/GL). The highest density of these fibers occurred in the anterior region of the bulb. The cellular targets of this cholinergic input were identified by exposing isolated OBs to acetylcholine receptor (AChR) agonists in the presence of agmatine (AGB), a cationic probe that permeates some active ion channels. Nicotine (50 microM) significantly increased the activity-dependent labeling of mitral cells and juxtaglomerular cells but not of tyrosine hydroxlase-positive dopaminergic neurons (TH(+) cells) compared to control preparations. The nAChR antagonist mecamylamine, an alpha7-nAChR subunit-specific antagonist, calcium-free artificial cerebrospinal fluid, or a cocktail of ionotropic glutamate receptor (iGluR) antagonists each blocked nicotine-stimulated labeling, suggesting that AGB does not enter the labeled neurons through activated nAChRs but rather through activated iGluRs following ACh-stimulated glutamate release. Deafferentation of OBs did not eliminate nicotine-stimulated labeling, suggesting that cholinergic input is primarily acting on bulbar neurons. These findings confirm the presence of a functioning cholinergic system in the zebrafish OB.
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Affiliation(s)
- Jeffrey G Edwards
- University of Utah School of Medicine, Department of Physiology, Salt Lake City, Utah 84108-1297, USA
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31
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Yu TY, Acosta ML, Ready S, Cheong YL, Kalloniatis M. Light exposure causes functional changes in the retina: increased photoreceptor cation channel permeability, photoreceptor apoptosis, and altered retinal metabolic function. J Neurochem 2007; 103:714-24. [PMID: 17623037 DOI: 10.1111/j.1471-4159.2007.04766.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Light exposure induces retinal photoreceptor degeneration and retinal remodeling in both the normal rat retina and in animal models of retinal degeneration. Although cation entry is one of the triggers leading to apoptosis, it is unclear if this event occurs in isolation, or whether a number of pathways lead to photoreceptor apoptosis following light exposure. Following light exposure, we investigated the characteristics of cation entry, apoptotic markers [using terminal deoxynucleotidyl transferase (EC 2.7.7.31) dUTP nick-end labeling (TUNEL) labeling] and metabolic properties of retina from Sprague-Dawley (SD) rats and a rat model of retinitis pigmentosa [proline-23-histidine (P23H) rat]. Assessment of cation channel permeability using agmatine (AGB) labeling showed that excessive cation gating accompanied the series of anomalies that occur prior to photoreceptor loss. Increased AGB labeling in photoreceptors was seen in parallel with the appearance of apoptotic photoreceptors detected by TUNEL labeling with only a smaller proportion of cells colocalizing both markers. However, SD and P23H retinal photoreceptors differed in the amounts and colocalization of AGB gating and TUNEL labeling as a function of light exposure. Finally, reduced retinal lactate dehydrogenase levels were found in SD and P23H rat retinas after a 24-h light exposure period. Short-term (2 h) exposure of the P23H rat retina caused an increase in lactate dehydrogenase activity suggesting increased metabolic demand. These results suggest that energy availability may be exacerbated during the early stages of light exposure in susceptible retinas. Also, the concomitant observation of increased ion gating and TUNEL labeling suggest the existence of at least two possible mechanisms in light-damaged retinas in both SD and the P23H rat retina.
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Affiliation(s)
- Tzu-Ying Yu
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
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32
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Puller C, Haverkamp S, Grünert U. OFF midget bipolar cells in the retina of the marmoset, Callithrix jacchus, express AMPA receptors. J Comp Neurol 2007; 502:442-54. [PMID: 17366611 DOI: 10.1002/cne.21315] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent studies suggested that different types of OFF bipolar cells express specific types of ionotropic (AMPA or kainate) glutamate receptors (GluRs) at their contacts with cone pedicles. However, the question of which GluR type is expressed by which type of OFF bipolar cell in primate retina is still open. In this study, the expression of AMPA and kainate receptor subunits at the dendritic tips of flat (OFF) midget bipolar (FMB) cells was analyzed in the retina of the common marmoset, Callithrix jacchus. We used preembedding electron microscopy and double immunofluorescence with subunit-specific antibodies. The FMB cells were labeled with antibodies against the carbohydrate epitope CD15. Cone pedicles were identified with peanut agglutinin. Immunoreactivity for the GluR1 subunit and for CD15 is preferentially located at triad-associated flat contacts. Furthermore, the large majority of GluR1 immunoreactive puncta is localized at the dendritic tips of FMB cells. These results suggest that FMB cells express the AMPA receptor subunit GluR1. In contrast, the kainate receptor subunit GluR5 is not colocalized with the dendritic tips of FMB cells or with the GluR1 subunit. Immunoreactive puncta for the GluR1 subunit are found at all M/L-cone pedicles but are only rarely associated with S-cone pedicles. This is consistent with our recent findings in marmoset retina that FMB cells do not contact S-cone pedicles. The presence of GluR5 clusters at S-cone pedicles indicates that in primate retinas OFF bipolar cells expressing kainate receptor subunits receive some S-cone input.
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Affiliation(s)
- Christian Puller
- Department of Neuroanatomy, Max-Planck-Institute for Brain Research, D-60528 Frankfurt/Main, Germany
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33
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Kwon OJ, Kim MS, Kim TJ, Jeon CJ. Identification of synaptic pattern of kainate glutamate receptor subtypes on direction-selective retinal ganglion cells. Neurosci Res 2007; 58:255-64. [PMID: 17466402 DOI: 10.1016/j.neures.2007.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Revised: 03/19/2007] [Accepted: 03/20/2007] [Indexed: 11/24/2022]
Abstract
In this article we investigate the distributions of kainate glutamate receptor subtypes GluR5-7 and KA1, 2 on the dendritic arbors of direction-selective (DS) retinal ganglion cells (RGCs) of the rabbit retina to search for anisotropies, which might contribute to a directional preference of DS RGCs. The distribution of the kainate receptor subunits on the DS RGCs was determined using antibody immunocytochemistry. DS RGCs were injected with Lucifer yellow and the cells were identified by their characteristic morphology. The double-labeled images of dendrites and receptors were visualized using confocal microscopy and were reconstructed from high-resolution confocal images. We found no evidence of asymmetry in any of the kainate receptor subunits examined on the dendritic arbors of both On and Off layers of DS RGCs. Our results indicate that direction selectivity appears to lie in the neuronal circuitry afferent to the ganglion cell.
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Affiliation(s)
- Oh-Ju Kwon
- Neuroscience Lab, Department of Biology, College of Natural Sciences, Kyungpook National University, 1370 Sankyuk-dong, Daegu 702-701, South Korea
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34
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Acosta ML, Bumsted O'Brien KM, Tan SS, Kalloniatis M. Emergence of cellular markers and functional ionotropic glutamate receptors on tangentially dispersed cells in the developing mouse retina. J Comp Neurol 2007; 506:506-23. [DOI: 10.1002/cne.21561] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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35
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Sun D, Vingrys AJ, Kalloniatis M. Metabolic and functional profiling of the normal rat retina. J Comp Neurol 2007; 505:92-113. [PMID: 17729258 DOI: 10.1002/cne.21478] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We established a metabolic and functional profile map of the normal rat retina, given the premise that: 1) amino acid neurochemistry reflects metabolic integrity and cellular identity, and 2) the permeation of a cation channel probe, agmatine (1-amino-4-guanidobutane, AGB), reflects cation channel functionality. The purpose was to provide a unique method of simultaneously assessing the metabolic and functional characteristics of the normal retina, upon which a comparison can be made to disease models. Quantitative pattern recognition analysis of overlapping amino acid and AGB expression profiles was used to provide a statistically robust classification of all neural elements according to their metabolic and functional characteristics. This classification was spatially complete and with single-cell resolution. The resulting classification demonstrated 28 statistically separable theme classes dominated by characteristic glutamate, GABA, glycine, and/or taurine profiles, with each of the neuronal theme classes containing further subtypes. The inclusion of a functional parameter (AGB mapping) in the classification process nearly doubled the number of neural elements that could be ascribed a neurochemical/cation profile, compared to when amino acid labeling was used alone. Strong endogenous glutamate gated AGB labeling was observed in horizontal cells, rod bipolar cells, cholinergic amacrine cells, and AII amacrine cells. The resulting amino acid and AGB profile matrix constitutes a nomogram for assessing cellular responses to experimental challenges in models of ocular disease.
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Affiliation(s)
- Daniel Sun
- Department of Optometry and Vision Science, University of Auckland, New Zealand
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36
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Dumitrescu ON, Protti DA, Majumdar S, Zeilhofer HU, Wässle H. Ionotropic glutamate receptors of amacrine cells of the mouse retina. Vis Neurosci 2006; 23:79-90. [PMID: 16597352 DOI: 10.1017/s0952523806231079] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 09/15/2005] [Indexed: 11/06/2022]
Abstract
The mammalian retina contains approximately 30 different morphological types of amacrine cells, receiving glutamatergic input from bipolar cells. In this study, we combined electrophysiological and pharmacological techniques in order to study the glutamate receptors expressed by different types of amacrine cells. Whole-cell currents were recorded from amacrine cells in vertical slices of the mouse retina. During the recordings the cells were filled with Lucifer Yellow/Neurobiotin allowing classification as wide-field or narrow-field amacrine cells. Amacrine cell recordings were also carried out in a transgenic mouse line whose glycinergic amacrine cells express enhanced green fluorescent protein (EGFP). Agonist-induced currents were elicited by exogenous application of NMDA, AMPA, and kainate (KA) while holding cells at −75 mV. Using a variety of specific agonists and antagonists (NBQX, AP5, cyclothiazide, GYKI 52466, GYKI 53655, SYM 2081) responses mediated by AMPA, KA, and NMDA receptors could be dissected. All cells (n= 300) showed prominent responses to non-NMDA agonists. Some cells expressed AMPA receptors exclusively and some cells expressed KA receptors exclusively. In the majority of cells both receptor types could be identified. NMDA receptors were observed in about 75% of the wide-field amacrine cells and in less than half of the narrow-field amacrine cells. Our results confirm that different amacrine cell types express distinct sets of ionotropic glutamate receptors, which may be critical in conferring their unique temporal responses to this diverse neuronal class.
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Affiliation(s)
- Olivia N Dumitrescu
- Department of Neuroanatomy, Max-Planck-Institute for Brain Research, Frankfurt/Main, Germany
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37
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Acosta ML, Chua J, Kalloniatis M. Functional activation of glutamate ionotropic receptors in the developing mouse retina. J Comp Neurol 2006; 500:923-41. [PMID: 17177257 DOI: 10.1002/cne.21225] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ionotropic glutamate receptors have been associated with early development of the visual process by regulating cell differentiation, cell motility, and synaptic contacts. We determined the expression of functional ionotropic glutamate receptors during development of the mouse retina by assessing 1-amino-4-guanidobutane (agmatine; AGB) immunolabelling after application of a range of glutamate analogs. Colocalization of AGB with calretinin and islet-1 allowed the identification of functional receptors in neurochemically defined neurons. Activation with kainate (KA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and N-methyl-D-aspartate (NMDA) resulted in AGB entry into neurons consistent with that found previous receptor subunit localization studies in the developing retina. Temporal analysis revealed that application of 50 microM KA activated receptors as early as embryonic day 18 in the ventricular zone and in the ganglion cell layer, whereas 30 muM AMPA activated cells predominantly in the ganglion cell layer. Cholinergic amacrine cells showed functional KA and AMPA receptors upon their insertion into the conventional amacrine cell layer from postnatal day 1 (P1). OFF cone bipolar cells showed functional KA receptors from P6, at a developmental age when they are known to make contact with ganglion cells. NMDA activation led to diffuse AGB labeling at birth among cells in the ganglion cell layer, whereas, at P1, regularly spaced cholinergic amacrine cells in the conventional amacrine cell layer started to be responsive to NMDA. Non-NMDA receptors were first to show functional activation in the developing retina, and cholinergic amacrine cells displayed functional ionotropic glutamate receptors after reaching their final destination.
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Affiliation(s)
- Monica L Acosta
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
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38
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Marc RE, Kalloniatis M, Jones BW. Excitation mapping with the organic cation AGB2+. Vision Res 2005; 45:3454-68. [PMID: 16139860 DOI: 10.1016/j.visres.2005.07.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 07/22/2005] [Accepted: 07/25/2005] [Indexed: 11/26/2022]
Abstract
Excitation mapping is a method of visualizing the signaling history of neurons with permeant organic cations. It is compatible with high-resolution imaging, allowing concurrent visualization of all neuronal classes and their glutamate-gated excitation histories. Excitation mapping documents the stability and precision of neuronal signaling within a given neuronal class, arguing that single unit electrophysiological sampling accurately reflects neuronal diversity. We here review the theory of excitation mapping, provide methods and protocol links; outline imaging concepts; provide parametric data on the temporal range and physiological sensitivity of excitation mapping; and show that immunocytochemical methods for macromolecules are compatible with excitation mapping.
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Affiliation(s)
- Robert E Marc
- John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, 84132, USA.
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39
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Jones BW, Marc RE. Retinal remodeling during retinal degeneration. Exp Eye Res 2005; 81:123-37. [PMID: 15916760 DOI: 10.1016/j.exer.2005.03.006] [Citation(s) in RCA: 304] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2005] [Accepted: 03/17/2005] [Indexed: 11/28/2022]
Abstract
Retinal degenerations, regardless of the initiating event or gene defect, often result in a loss of photoreceptors. This formal deafferentation of the neural retina eliminates the intrinsic glutamatergic drive of the sensory retina and, perhaps more importantly, removes coordinated Ca++-coupled signaling to the neural retina. As in other central nervous system degenerations, deafferentation activates remodeling. Neuronal remodeling is the common fate of all photoreceptor degenerations.
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Affiliation(s)
- Bryan W Jones
- Moran Eye Center, 75 North Medical Drive, Rm 3339A, Salt Lake City, UT 84132, USA.
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40
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Eldred WD, Blute TA. Imaging of nitric oxide in the retina. Vision Res 2005; 45:3469-86. [PMID: 16171845 PMCID: PMC1464841 DOI: 10.1016/j.visres.2005.07.033] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 07/22/2005] [Accepted: 07/25/2005] [Indexed: 11/18/2022]
Abstract
Nitric oxide (NO) is the most widespread signaling molecule found in the retina in that it can be made by every retinal cell type. NO is able to influence a wide variety of synaptic mechanisms ranging from increasing or decreasing neurotransmitter release to the modulation of gap junction conductivity. Although biochemical methods can analyze overall levels of NO, such methods cannot indicate the specific cell types involved. In the last few years, fluorescent imaging methods utilizing diaminofluorescein have allowed the real-time visualization of neurochemically or light stimulated NO-induced fluorescence (NO-IF) in specific retinal cells. Recent experiments have shown that this NO-IF can be stabilized using paraformaldehyde fixation. This aldehyde stabilization has allowed the imaging of NO production in the dark and in response to light, as well as the neurochemical modulation of light stimulated NO production. The results of these studies indicate that NO is not always freely diffusible and that NO is largely retained in many cells which make it. The NO production in retina is highly damped in that in the absence of stimulation, the endogenous levels of NO production are extremely low. Finally, different neurochemical or light stimulation protocols activate NO production in specific cells and subcellular compartments. Therefore, although the NO signaling is widespread in retina, it is very selectively activated and has different functions in specific retinal cell types. The use of NO imaging will continue to play a critical role in future studies of the function of NO in retina and other neural systems.
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Affiliation(s)
- William D Eldred
- Laboratory of Visual Neurobiology, Department of Biology, Boston University, MA 02215, USA.
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41
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Kalloniatis M, Sun D, Foster L, Haverkamp S, Wässle H. Localization of NMDA receptor subunits and mapping NMDA drive within the mammalian retina. Vis Neurosci 2005; 21:587-97. [PMID: 15595182 DOI: 10.1017/s0952523804214080] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Glutamate is a major neurotransmitter in the retina and other parts of the central nervous system, exerting its influence through ionotropic and metabotropic receptors. One ionotropic receptor, the N-methyl-D-aspartate(NMDA) receptor, is central to neural shaping, but also plays a major role during neuronal development and in disease processes. We studied the distribution pattern of different subunits of the NMDA receptor within the rat retina including quantifying the pattern of labelling for all the NRI splice variants, the NR2A and NR2B subunits. The labelling pattern for the subunits was confined predominantly in the outer two-thirds of the inner plexiform layer. We also wanted to probe NMDA receptor function using an organic cation, agmatine (AGB); a marker for cation channel activity. Although there was an NMDA concentration-dependent increase in AGB labelling of amacrine cells and ganglion cells, we found no evidence of functional NMDA receptors on horizontal cells in the peripheral rabbit retina, nor in the visual streak where the type A horizontal cell was identified by GABA labelling. Basal AGB labelling within depolarizing bipolar cells was also noted. This basal bipolar cell AGB labelling was not modulated by NMDA and was completely abolished by the use of L-2-amino-4-phosphono-butyric acid,which is known to hyperpolarize retinal depolarizing bipolar cells. AGB is therefore not only useful as a probe of ligand-gated drive, but can also identify neurons that have constitutively open cationic channels. In combination,the NMDA receptor subunit distribution pattern and the AGB gating experiments strongly suggests that this ionotropic glutamate receptor is functional in the cone-driven pathway of the inner retina.
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Affiliation(s)
- Michael Kalloniatis
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.
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42
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Sun D, Kalloniatis M. Mapping glutamate responses in immunocytochemically identified neurons of the mouse retina. J Comp Neurol 2005; 494:686-703. [PMID: 16374798 DOI: 10.1002/cne.20813] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The mammalian retina contains as many as 50-60 unique cell types, many of which have been identified using various neurochemical markers. Retinal neurons express N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxyl-5-methylisoxazole-4-propionic acid (AMPA), and kainic acid (KA) receptor subunits in various mixtures, densities, and spatial distributions. Ionotropic glutamatergic drive in retinal neurons can be mapped using a cation channel permeant guanidinium analog called agmatine (1-amino-4-guanidobutane; AGB). This alternative approach to physiologically characterize neurons in the retina was introduced by Marc (1999, J Comp Neurol 407:47-64, 407:65-76), and allows the simultaneous mapping of responses of glutamate receptor-gated channels from an entire population of neurons. Unlike previous AGB studies, we colocalized AGB with various macromolecular markers using direct and indirect immunofluorescence to characterize the glutamate agonist sensitivities of specific cell types. Activation with NMDA, AMPA, and KA resulted in AGB entry into neurons in a dose-dependent manner and was consistent with previous receptor subunit localization studies. Consistent with the various morphological phenotypes encompassed by the calbindin and calretinin immunoreactive cells, we observed various functional phenotypes revealed by AGB labeling. Not all calbindin or calretinin immunoreactive cells showed ligand-evoked AGB permeation. A small proportion either did not possess functional glutamate receptors, required higher activation thresholds, or express functional channels impermeable to AGB. AMPA and KA activation of bipolar cells resulted in AGB permeation into the hyperpolarizing variety only. We also studied the glutamate ligand-gating properties of 3[alpha1-3]-fucosyl-N-acetyl-lactosamine (CD15) immunoreactive cells and show functional responses consistent with receptor subunit gene expression patterns. CD15-immunoreactive bipolar cells only responded to AMPA but not KA. The CD15 immunoreactive amacrine cells demonstrated an identical selectivity to AMPA activation, but were also responsive to NMDA. Finally, localization of AGB secondary to glutamate receptor activation was visualized with a permanent reaction product.
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Affiliation(s)
- Daniel Sun
- Department of Optometry and Vision Science, University of Auckland, Auckland 1020, New Zealand
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43
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Blaszczyk WM, Telkes I, Distler C. GABA-immunoreactive starburst amacrine cells in pigmented and albino rats. Eur J Neurosci 2004; 20:3195-8. [PMID: 15579175 DOI: 10.1111/j.1460-9568.2004.03761.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this study we tested whether the critical anatomical substrate for retinal direction selectivity is altered in albino mammals. We used dual immunostaining for GABA and choline acetyltransferase and quantitatively analyzed the number of double-labelled starburst amacrine cells in wild-type and albino rats. In albino rats, the percentage of ON-amacrine cells with high GABA content was significantly lower than in pigmented animals. OFF-amacrines did not significantly differ between the two rat strains. Thus, the decreased GABA content in ON-amacrine cells could reflect an altered neuronal substrate for retinal direction selectivity. These results are discussed in relation to the optokinetic deficits described in albino mammals.
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Affiliation(s)
- W M Blaszczyk
- Allgemeine Zoologie und Neurobiologie, Ruhr-Universität Bochum, Postfach 102148, D-44780 Bochum, Germany
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44
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Rohrer B, Blanco R, Marc RE, Lloyd MB, Bok D, Schneeweis DM, Reichardt LF. Functionally intact glutamate-mediated signaling in bipolar cells of the TRKB knockout mouse retina. Vis Neurosci 2004; 21:703-13. [PMID: 15683558 PMCID: PMC2710101 DOI: 10.1017/s095252380421505x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2004] [Indexed: 01/19/2023]
Abstract
In the juvenile trkB knockout (trkB−/−) mouse, retina synaptic communication from rods to bipolar cells is severely compromised as evidenced by a complete absence of electroretinogram (ERG)b-wave, even though the inner retina appears anatomically normal (Rohrer et al., 1999). Since it is well known that theb-wave reflects light-dependent synaptic activation of ON bipolar cellsviatheir metabotropic glutamate receptor, mGluR6, we sought to analyze the anatomical and functional integrity of the glutamatergic synapses at these and other bipolar cells in thetrkB−/−mouse. Although rod bipolar cells from wild-type juvenile mice were determined to be immunopositive for trkB, postsynaptic metabotropic and ionotropic glutamate receptor-mediated pathways in ON and OFF bipolar cells were found to be functionally intact, based on patch electrode recordings, using brief applications (“puffs”) of glutamate or its analog, 2-amino-4-phosphonobutyric acid (APB), a selective agonist for mGluR6 receptors. Ionotropic glutamate receptor function was assayed in OFF-cone bipolar and horizontal cells by applying exogenous glutamatergic agonists in the presence of the channel-permeant guanidinium analogue, 1-amino-4-guanidobutane (AGB). Electron-microscopic analysis revealed that the ribbon synapses between rods and postsynaptic rod bipolar and horizontal cells were formed at the appropriate age and appear to be structurally intact, and immunohistochemical analysis did not detect profound defects in the expression of excitatory amino acid transporters involved in glutamate clearance from the synaptic cleft. These data indicate that there does not appear to be evidence for postsynaptic deficits in glutamatergic signaling in the ON and OFF bipolar cells of mice lacking trkB.
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Affiliation(s)
- Baerbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charlston, SC 29425, USA.
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45
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Farajian R, Raven MA, Cusato K, Reese BE. Cellular positioning and dendritic field size of cholinergic amacrine cells are impervious to early ablation of neighboring cells in the mouse retina. Vis Neurosci 2004; 21:13-22. [PMID: 15137578 DOI: 10.1017/s0952523804041021] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have examined the role of neighbor relationships between cholinergic amacrine cells upon their positioning and dendritic field size by producing partial ablations of this population of cells during early development. We first determined the effectiveness of L-glutamate as an excitotoxin for ablating cholinergic amacrine cells in the developing mouse retina. Subcutaneous injections (4 mg/g) made on P-3 and thereafter were found to produce a near-complete elimination, while injections at P-2 were ineffective. Lower doses on P-3 produced only partial reductions, and were subsequently used to examine the effect of partial ablation upon mosaic organization and dendritic growth of the remaining cells. Four different Voronoi-based measures of mosaic geometry were examined in L-glutamate-treated and normal (saline-treated) retinas. Partial depletions of around 40% produced cholinergic mosaics that, when scaled for density, approximated the mosaic geometry of the normal retina. Separate comparisons simulating a 40% random deletion of the normal retina produced mosaics that were no different from those experimentally depleted retinas. Consequently, no evidence was found for positional regulation in the absence of normal neighbor relationships. Single cells in the ganglion cell layer were intracellularly filled with Lucifer Yellow to examine the morphology and dendritic field extent following partial ablation of the cholinergic amacrine cells. No discernable effect was found on their starburst morphology, and total dendritic field area, number of primary dendrites, and branch frequency were not significantly different. Cholinergic amacrine cells normally increase their dendritic field area after P-3 in excess of retinal expansion; despite this, the present results show that this growth is not controlled by the density of neighboring processes.
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Affiliation(s)
- Reza Farajian
- Neuroscience Research Institute, Department of Psychology, University of California at Santa Barbara, Santa Barbara 93106-5060, USA
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46
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Lindsay SM, Riordan TJ, Forest D. Identification and activity-dependent labeling of peripheral sensory structures on a spionid polychaete. THE BIOLOGICAL BULLETIN 2004; 206:65-77. [PMID: 15111361 DOI: 10.2307/1543537] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In marine sedimentary habitats, chemoreception is thought to coordinate feeding in many deposit-feeding invertebrates such as polychaetes, snails, and clams. Relatively little is known, however, about the chemosensory structures and mechanism of signal transduction in deposit feeders. Using electron microscopy, confocal laser scanning microscopy (CLSM), and immunohistochemistry, we investigated the structure and function of putative chemosensory cells on the feeding appendages of a deposit-feeding polychaete species, Dipolydora quadrilobata. Tufts of putative sensory cilia were distributed over the prostomium and feeding palps and typically occurred next to pores. Examination of these regions with transmission electron microscopy revealed multiciliated cells with adjacent glandular cells beneath the pores. The sensory cells of prostomium and palps were similar, displaying an abundance of apical mitochondria and relatively short ciliary rootlets. Staining with antiserum against acetylated alpha-tubulin was examined by CLSM, and revealed axonal processes from putative sensory tufts on the palp surface to palp nerves, as well as many free nerve endings. Activity-dependent cell labeling experiments were used to test the sensitivity of putative sensory cells on the palps to an amino acid mixture that elicited feeding in previous behavioral experiments. In static exposures, the number of lateral and abfrontal cells labeled in response to the amino acid mixture was significantly greater than in the controls. Ultrastructural, positional, and now physiological evidence strongly suggests that spionid feeding palps are equipped with sensory cells, at least some of which function as chemoreceptors.
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Affiliation(s)
- Sara M Lindsay
- School of Marine Sciences, 5751 Murray Hall, University of Maine, Orono, Maine 04469, USA.
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Abstract
During development, retinal ganglion cells undergo conspicuous structural remodeling as they gradually attain their mature morphology and connectivity. Alterations in their dendritic organization and in their axonal projections can also be achieved following early insult to their targets or their afferents. Other retinal cell types are thought not to display this same degree of developmental plasticity. The present review will consider the evidence, drawn largely from recent experimental studies in the carnivore retina, that photoreceptors also undergo structural remodeling, extending their terminals transiently into inner plexiform layer before retracting to the outer plexiform layer. The determinants of this transient targeting to the inner plexiform layer are considered, and the role of cholinergic amacrine cells is discussed. The factors triggering this retraction are also considered, including the concurrent maturational changes in outer segment formation and in the differentiation of the outer plexiform layer. These results provide new insight into the life history of the photoreceptor cell and its connectivity, and suggest a transient role for the photoreceptors in the circuitry of the inner retina during early development, prior to the onset of phototransduction.
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Affiliation(s)
- Benjamin E Reese
- Neuroscience Research Institute, Department of Psychology, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, USA.
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Osborne NN, Casson RJ, Wood JPM, Chidlow G, Graham M, Melena J. Retinal ischemia: mechanisms of damage and potential therapeutic strategies. Prog Retin Eye Res 2004; 23:91-147. [PMID: 14766318 DOI: 10.1016/j.preteyeres.2003.12.001] [Citation(s) in RCA: 737] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Retinal ischemia is a common cause of visual impairment and blindness. At the cellular level, ischemic retinal injury consists of a self-reinforcing destructive cascade involving neuronal depolarisation, calcium influx and oxidative stress initiated by energy failure and increased glutamatergic stimulation. There is a cell-specific sensitivity to ischemic injury which may reflect variability in the balance of excitatory and inhibitory neurotransmitter receptors on a given cell. A number of animal models and analytical techniques have been used to study retinal ischemia, and an increasing number of treatments have been shown to interrupt the "ischemic cascade" and attenuate the detrimental effects of retinal ischemia. Thus far, however, success in the laboratory has not been translated to the clinic. Difficulties with the route of administration, dosage, and adverse effects may render certain experimental treatments clinically unusable. Furthermore, neuroprotection-based treatment strategies for stroke have so far been disappointing. However, compared to the brain, the retina exhibits a remarkable natural resistance to ischemic injury, which may reflect its peculiar metabolism and unique environment. Given the increasing understanding of the events involved in ischemic neuronal injury it is hoped that clinically effective treatments for retinal ischemia will soon be available.
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Affiliation(s)
- Neville N Osborne
- Nuffield Laboratory of Ophthalmology, University of Oxford, Walton Street, Oxford OX2 6AW, UK.
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FIRTH SALLYI, LI WEI, MASSEY STEPHENC, MARSHAK DAVIDW. AMPA receptors mediate acetylcholine release from starburst amacrine cells in the rabbit retina. J Comp Neurol 2003; 466:80-90. [PMID: 14515241 PMCID: PMC3341736 DOI: 10.1002/cne.10880] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The light response of starburst amacrine cells is initiated by glutamate released from bipolar cells. To identify the receptors that mediate this response, we used a combination of anatomical and physiological techniques. An in vivo, rabbit eyecup was preloaded with [(3)H]-choline, and the [(3)H]-acetylcholine (ACh) released into the superfusate was monitored. A photopic, 3 Hz flashing light increased ACh release, and the selective AMPA receptor antagonist, GYKI 53655, blocked this light-evoked response. Nonselective AMPA/kainate agonists increased the release of ACh, but the specific kainate receptor agonist, SYM 2081, did not increase ACh release. Selective AMPA receptor antagonists, GYKI 53655 or GYKI 52466, also blocked the responses to agonists. We conclude that the predominant excitatory input to starburst amacrine cells is mediated by AMPA receptors. We also labeled lightly fixed rabbit retinas with antisera to choline acetyltransferase (ChAT), AMPA receptor subunits GluR1, GluR2/3, or GluR4, and kainate receptor subunits GluR6/7 and KA2. Labeled puncta were observed in the inner plexiform layer with each of these antisera to glutamate receptors, but only GluR2/3-IR puncta and GluR4-IR puncta were found on the ChAT-IR processes. The same was true of starburst cells injected intracellularly with Neurobiotin, and these AMPA receptor subunits were localized to two populations of puncta. The AMPA receptors are expected to desensitize rapidly, enhancing the sensitivity of starburst amacrine cells to moving or other rapidly changing stimuli.
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Affiliation(s)
- SALLY I. FIRTH
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, Texas, 77225
| | - WEI LI
- Department of Ophthalmology and Visual Sciences, University of Texas Medical School, Houston, Texas 77225
- Graduate School of Biomedical Sciences, University of Texas Health Sciences Center, Houston, Texas 77225
| | - STEPHEN C. MASSEY
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, Texas, 77225
- Department of Ophthalmology and Visual Sciences, University of Texas Medical School, Houston, Texas 77225
| | - DAVID W. MARSHAK
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, Texas, 77225
- Department of Ophthalmology and Visual Sciences, University of Texas Medical School, Houston, Texas 77225
- Correspondence to: David W. Marshak, Department of Neurobiology and Anatomy, University of Texas, Houston Medical School, 6431 Fannin St., Houston, TX 77030.
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Kim D, Kim MJ, Lee JH, Im JO, Won YJ, Yoon SY, Hong HN. Concomitant distribution shift of glial GABA transporter and S100 calcium-binding proteins in the rat retina after kainate-induced excitotoxic injury. Neurosci Lett 2003; 353:17-20. [PMID: 14642427 DOI: 10.1016/j.neulet.2003.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The goal of this study was to elucidate the involvement of neuronal and glial calcium-binding proteins in the stimulation of gamma-aminobutyric acid (GABA) transport system by kainate-induced excitotoxicity in the rat retina. We used immunohistochemical method to assess the localization of GABA reuptake and calcium-binding proteins. After systemic administration of kainate, the neuronal GABA transporter does not show an association with calbindin D-28K. However, the localization of the GAT-3 transport system in Müller glial cells is closely correlated with the S100 proteins interacting with glial fibrillary acidic protein (GFAP) in response to kainate injury. Furthermore, we demonstrate that kainate-mediated excitotoxicity induced concomitant distribution shift of glial GABA transporter, S100 proteins and GFAP in the distal processes and endfeet of glial cells during the first 48 h.
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Affiliation(s)
- Donghou Kim
- Department of Anatomy and Cell Biology, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, South Korea
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