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Sample records for cat retinal ganglion

  1. Three factors limiting the reliable detection of light by retinal ganglion cells of the cat

    PubMed Central

    Barlow, H. B.; Levick, W. R.

    1969-01-01

    1. Responses of cat retinal ganglion cells have been examined with a view to specifying the characteristics that limit the detection of light stimuli. 2. Threshold is defined as the weakest stimulus that can be reliably detected by examination of the output from a retinal ganglion cell; it depends upon (a) the quantum/spike ratio, which is the mean number of additional quantal absorptions required to produce an additional impulse, (b) the temporal course of the response, which determines the time interval within which the maintained discharge is modified, and (c) the statistical distribution of the number of impulses that occur in this time interval in the absence of the stimulus. 3. The quantum/spike ratio changes greatly when adapting luminance is changed, and this is the predominant factor accounting for changes in increment threshold. 4. The time course of the response changes with adaptation level and area of the stimulus. This may account for the changes in temporal integration that occur in analogous psychophysical experiments. 5. Changes in the irregularity of the maintained discharge also affect the threshold of single ganglion cells. This is only a minor factor in the conditions of most of our experiments, but it may be important when unstabilized images and non-equilibrium adaptation conditions are encountered. PMID:5761942

  2. Frequency transfer properties of the spike generating mechanism of cat retinal ganglion cells.

    PubMed

    Lankheet, M J; Molenaar, J; van de Grind, W A

    1989-01-01

    The dynamic properties of the spike generating (SG) mechanism of retinal ganglion cells have been studied from intracellular recordings in the cat eye. Intracellularly recorded light flicker responses were separated by computer into spike trains and corresponding generator potentials. Both the spike train and the generator potential responses to temporally modulated light spots were analysed in terms of amplitude and phase plots. The differences in dynamic properties between the two response measures reveal that the SG-mechanism affects the temporal frequency transfer properties of retinal ganglion cells to a considerable extent. With respect to the transfer of the amplitude of the first harmonic the SG-mechanism has differentiating (or high-pass) properties. This means that the responses to high temporal stimulus frequencies are amplified relatively much more than are the responses to lower frequencies. Furthermore, the SG-mechanism causes a phase lead of the spike train response relative to the generator potential by, on average, 37 degrees. The measured frequency responses, among other things, have been used to verify and to quantify the SG-model that we proposed in a previous paper (Lankheet, Molenaar & van de Grind, 1989). With this model it proved possible to reproduce the spike train responses as model output from the corresponding measured generator potentials as model input. A good qualitative and quantitative correspondence between model output and the measured spike trains was obtained for a wide range of stimulus frequencies and with fixed values of the model parameters. With parameter values that optimized this correspondence the model allowed us to investigate the dynamic behaviour of the SG-mechanism in more detail. It also provides a reliable and validated method to predict the shape of the generator potential from the spike train (the "inversion problem").

  3. Sustained and transient discharges of retinal ganglion cells during spontaneous eye movements of cat.

    PubMed

    Noda, H

    1975-02-14

    Discharges of 223 retinal ganglion cells during spontaneous eye movements (saccades) across a stationary grating pattern were studied in chronically prepared cats. Of these 83 showed sustained responses to local differences in luminance of the grating stripes (S-units); 84 showed transient responses to saccades and did not register local differences in luminance (T-units); and 56 showed mixed responses, i.e., transient responses to saccades and sustained firings in response to local luminance (M-units). When tested with diffuse light, 93.9% of the S-units showed either ON-sustained or OFF-sustained responses; 95.2% of the T-units showed either ON-transient, OFF-transient, or ON-OFF-transient responses; and 50% of the M-units showed ON-OFF responses. In the overall responses properties, most S-units corresponded to the X-cells, most T-units to the Y-cells of retinal ganglion cells previously known from acute experiments. Under normal conditions of active eye movements, the major function of the S-units would be to register the differences in luminance in their receptive fields, and subserve the mechansim of form recognition. The major function of the T-units would be to register information related to quick image motion, induced either by eye or object movements, and subserve the mechanism of detecting the dynamic aspects of visual stimuli. The other important functions of the T-units are their possible participation in the afferent routes for two recently proposed mechanisms; one for goal-directed saccades and the other for saccadic suppression. The M-units would possess the functions of both S- and T-units.

  4. Cat retinal ganglion cell receptive-field alterations after 6-hydroxydopamine induced dopaminergic amacrine cell lesions

    SciTech Connect

    Maguire, G.W.; Smith, E.L. III

    1985-06-01

    Optic tract single-unit recordings were used to study ganglion cell response functions of the intact cat eye after 6-hydroxydopamine (6-OHDA) lesioning of the dopaminergic amacrine cell (AC) population of the inner retina. The impairment of the dopaminergic AC was verified by high pressure-liquid chromatography with electrochemical detection of endogenous dopamine content and by (/sup 3/H)dopamine high-affinity uptake; the dopaminergic ACs of the treated eyes demonstrated reduced endogenous dopamine content and reduced (/sup 3/H)dopamine uptake compared with that of their matched controls. Normal appearing (/sup 3/H)GABA and (/sup 3/H)-glycine uptake in the treated retinas suggests the absence of any nonspecific action of the 6-OHDA on the neural retina. The impairment of the dopaminergic AC population was found to alter a number of response properties in off-center ganglion cells, but this impairment had only a modest effect on the on-center cells. An abnormally high proportion of the off-center ganglion cells in the 6-OHDA treated eyes possessed nonlinear, Y-type receptive fields. These cells also possessed shift-responses of greater than normal amplitude, altered intensity-response functions, reduced maintained activities, and more transient center responses. Of the on-center type cells, only the Y-type on-center cells were affected by 6-OHDA, possessing higher than normal maintained activities and altered intensity-response functions. The on-center X-cells were unaffected by 6-OHDA treatment. The dopaminergic AC of the photopically adapted cat retina therefore modulates a number of ganglion cell response properties and within the limits of this study is most prominent in off-center ganglion cell circuitry.

  5. Protective Effect of ALA in Crushed Optic Nerve Cat Retinal Ganglion Cells Using a New Marker RBPMS

    PubMed Central

    Wang, Yanling; Wang, Wenyao; Liu, Jessica; Huang, Xin; Liu, Ruixing; Xia, Huika; Brecha, Nicholas C.; Pu, Mingliang; Gao, Jie

    2016-01-01

    In this study we first sought to determine whether RNA-binding protein with multiple splicing (RBPMS) can serve as a specific marker for cat retina ganglion cells (RGCs) using retrograde labeling and immunohistochemistry staining. RBPM was then used as an RGC marker to study RGC survival after optic nerve crush (ONC) and alpha-lipoic acid (ALA) treatment in cats. ALA treatment yielded a peak density of RBPMS-alpha cells within the peak isodensity zone (>60/mm2) which did not differ from ONC retinas. The area within the zone was significantly enlarged (control: 2.3%, ONC: 0.06%, ONC+ALA: 0.1%). As for the 10-21/mm2 zone, ALA treatment resulted in a significant increase in area (control: 34.5%, ONC: 12.1%, ONC+ALA: 35.9%). ALA can alleviate crush-induced RGC injury. PMID:27504635

  6. Topography of ganglion cell production in the cat's retina

    SciTech Connect

    Walsh, C.; Polley, E.H.

    1985-03-01

    The ganglion cells of the cat's retina form several classes distinguishable in terms of soma size, axon diameter, dendritic morphology, physiological properties, and central connections. Labeling with (/sup 3/H)thymidine shows that the ganglion cells which survive in the adult are produced as several temporally shifted, overlapping waves: medium-sized cells are produced before large cells, whereas the smallest ganglion cells are produced throughout the period of ganglion cell generation. Large cells and medium-sized cells show the same distinctive pattern of production, forming rough spirals around the area centralis. The oldest cells tend to lie superior and nasal to the area centralis, whereas cells in the inferior nasal retina and inferior temporal retina are, in general, progressively younger. Within each retinal quadrant, cells nearer the area centralis tend to be older than cells in the periphery, but there is substantial overlap. The retinal raphe divides the superior temporal quadrant into two zones with different patterns of cell addition. Superior temporal retina near the vertical meridian adds cells only slightly later than superior nasal retina, whereas superior temporal retina near the horizontal meridian adds cells very late, contemporaneously with inferior temporal retina. The broader wave of production of smaller ganglion cells seems to follow this same spiral pattern at its beginning and end. The presence of the area centralis as a nodal point about which ganglion cell production in the retinal quadrants pivots suggests that the area centralis is already an important retinal landmark even at the earliest stages of retinal development.

  7. Taurine deficiency damages retinal neurones: cone photoreceptors and retinal ganglion cells.

    PubMed

    Gaucher, David; Arnault, Emilie; Husson, Zoé; Froger, Nicolas; Dubus, Elisabeth; Gondouin, Pauline; Dherbécourt, Diane; Degardin, Julie; Simonutti, Manuel; Fouquet, Stéphane; Benahmed, M A; Elbayed, K; Namer, Izzie-Jacques; Massin, Pascale; Sahel, José-Alain; Picaud, Serge

    2012-11-01

    In 1970s, taurine deficiency was reported to induce photoreceptor degeneration in cats and rats. Recently, we found that taurine deficiency contributes to the retinal toxicity of vigabatrin, an antiepileptic drug. However, in this toxicity, retinal ganglion cells were degenerating in parallel to cone photoreceptors. The aim of this study was to re-assess a classic mouse model of taurine deficiency following a treatment with guanidoethane sulfonate (GES), a taurine transporter inhibitor to determine whether retinal ganglion cells are also affected. GES treatment induced a significant reduction in the taurine plasma levels and a lower weight increase. At the functional level, photopic electroretinograms were reduced indicating a dysfunction in the cone pathway. A change in the autofluorescence appearance of the eye fundus was explained on histological sections by an increased autofluorescence of the retinal pigment epithelium. Although the general morphology of the retina was not affected, cell damages were indicated by the general increase in glial fibrillary acidic protein expression. When cell quantification was achieved on retinal sections, the number of outer/inner segments of cone photoreceptors was reduced (20 %) as the number of retinal ganglion cells (19 %). An abnormal synaptic plasticity of rod bipolar cell dendrites was also observed in GES-treated mice. These results indicate that taurine deficiency can not only lead to photoreceptor degeneration but also to retinal ganglion cell loss. Cone photoreceptors and retinal ganglion cells appear as the most sensitive cells to taurine deficiency. These results may explain the recent therapeutic interest of taurine in retinal degenerative pathologies.

  8. Ih without Kir in Adult Rat Retinal Ganglion Cells

    PubMed Central

    Lee, Sherwin C.; Ishida, Andrew T.

    2011-01-01

    Antisera directed against hyperpolarization-activated mixed-cation (“Ih”) and K+ (“Kir”) channels bind to some somata in the ganglion cell layer of rat and rabbit retina. Additionally, the termination of hyperpolarizing current injections can trigger spikes in some cat retinal ganglion cells, suggesting a rebound depolarization due to activation of Ih. However, patch-clamp studies have reported that rat ganglion cells lack inward rectification, or present an inwardly rectifying K+ current. We therefore tested whether hyperpolarization activates Ih in dissociated, adult rat retinal ganglion cell somata. We report here that while we found no inward rectification in some cells, and a Kir-like current in a few cells, hyperpolarization activated Ih in roughly 75% of the cells we recorded from in voltage clamp. We show that this current is blocked by Cs+ or ZD7288 and only slightly reduced by Ba2+, that the current amplitude and reversal potential are sensitive to extracellular Na+ and K+, and that we found no evidence of Kir in cells presenting Ih. In current clamp, injecting hyperpolarizing current induced a slowly relaxing membrane hyperpolarization that rebounded to a few action potentials when the hyperpolarizing current was stopped; both the membrane potential relaxation and rebound spikes were blocked by ZD7288. These results provide the first measurement of Ih in mammalian retinal ganglion cells, and indicate that the ion channels of rat retinal ganglion cells may vary in ways not expected from previous voltage and current recordings. PMID:17488978

  9. Intrinsically photosensitive retinal ganglion cells.

    PubMed

    Do, Michael Tri Hoang; Yau, King-Wai

    2010-10-01

    Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors.

  10. Changes in ganglion cells during retinal degeneration.

    PubMed

    Saha, Susmita; Greferath, Ursula; Vessey, Kirstan A; Grayden, David B; Burkitt, Anthony N; Fletcher, Erica L

    2016-08-04

    Inherited retinal degeneration such as retinitis pigmentosa (RP) is associated with photoreceptor loss and concomitant morphological and functional changes in the inner retina. It is not known whether these changes are associated with changes in the density and distribution of synaptic inputs to retinal ganglion cells (RGCs). We quantified changes in ganglion cell density in rd1 and age-matched C57BL/6J-(wildtype, WT) mice using the immunocytochemical marker, RBPMS. Our data revealed that following complete loss of photoreceptors, (∼3months of age), there was a reduction in ganglion cell density in the peripheral retina. We next examined changes in synaptic inputs to A type ganglion cells by performing double labeling experiments in mice with the ganglion cell reporter lines, rd1-Thy1 and age-matched wildtype-Thy1. Ribbon synapses were identified by co-labelling with CtBP2 (RIBEYE) and conventional synapses with the clustering molecule, gephyrin. ON RGCs showed a significant reduction in RIBEYE-immunoreactive synapse density while OFF RGCs showed a significant reduction in the gephyrin-immmunoreactive synapse density. Distribution patterns of both synaptic markers across the dendritic trees of RGCs were unchanged. The change in synaptic inputs to RGCs was associated with a reduction in the number of immunolabeled rod bipolar and ON cone bipolar cells. These results suggest that functional changes reported in ganglion cells during retinal degeneration could be attributed to loss of synaptic inputs. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. Morphological properties of mouse retinal ganglion cells.

    PubMed

    Coombs, J; van der List, D; Wang, G-Y; Chalupa, L M

    2006-06-19

    The mouse retina offers an increasingly valuable model for vision research given the possibilities for genetic manipulation. Here we assess how the structural properties of mouse retinal ganglion cells relate to the stratification pattern of the dendrites of these neurons within the inner plexiform layer. For this purpose, we used 14 morphological measures to classify mouse retinal ganglion cells parametrically into different clusters. Retinal ganglion cells were labeled in one of three ways: Lucifer Yellow injection, 'DiOlistics' or transgenic expression of yellow fluorescent protein. The resulting analysis of 182 cells revealed 10 clusters of monostratified cells, with dendrites confined to either On or Off sublaminae of the inner plexiform layer, and four clusters of bistratified cells, dendrites spanning the On and Off sublaminae. We also sought to establish how these parametrically identified retinal ganglion cell clusters relate to cell types identified previously on the basis of immunocytochemical staining and the expression of yellow fluorescent protein. Cells labeled with an antibody against melanopsin were found to be located within a single cluster, while those labeled with the SMI-32 antibody were in four different clusters. Yellow fluorescent protein expressing cells were distributed within 13 of the 14 clusters identified here, which demonstrates that yellow fluorescent protein expression is a useful method for labeling virtually the entire population of mouse retinal ganglion cells. Collectively, these findings provide a valuable baseline for future studies dealing with the effects of genetic mutations on the morphological development of these neurons.

  12. Morphology of retinal ganglion cells in the flying fox (Pteropus scapulatus): a lucifer yellow investigation.

    PubMed

    Dann, J F; Buhl, E H

    1990-11-15

    The morphology of retinal ganglion cells was determined in megachiroptera, commonly known as flying foxes. Retinal ganglion cells were intracellularly injected with the fluorescent dye Lucifer yellow in fixed retinae from adult little red flying foxes (Pteropus scapulatus) captured in their natural habitat. Ganglion cells closely resembled the three main classes of cat retinal ganglion cells, and therefore were classified into alpha-, beta-, and gamma-type cells. The size of the alpha- and beta-type somas and dendritic fields increased with increasing distance from the area centralis. However, this eccentricity dependence was not as pronounced as in the cat. The gamma-type cells were sub-divided into mono-, bi-, and diffusely stratified, in accordance with the ramification of their dendrites within the inner plexiform layer. The alpha- and beta-type cells were uni-stratified in either the sublamina of the inner plexiform layer closest to the ganglion cell layer or in that closest to the inner nuclear layer. These laminae correspond to those in the cat retina which contain the dendritic ramifications of ganglion cells whose central receptive fields respond best to onset of light (the "on-centre" cells), or to ganglion cells whose centres respond optimally to light being extinguished (the "off-centre" cells). Thus the flying fox retina contains a morphological correlate of the "on"/"off" dichotomy of alpha and beta cells in the cat retina. In general the flying fox retinal ganglion cells exhibit a degree of morphological complexity reminiscent of cat retinal cells and this may reflect similar functional properties.

  13. Dissociation of Retinal Ganglion Cells Without Enzymes

    PubMed Central

    Hayashida, Yuki; Partida, Gloria J.; Ishida, Andrew T.

    2011-01-01

    We describe here methods for dissociating retinal ganglion cells from adult goldfish and rat without proteolytic enzymes, and show responses of ganglion cells isolated this way to step-wise voltage changes and fluctuating current injections. Taking advantage of the laminar organization of vertebrate retinas, photoreceptors and other cells were lifted away from the distal side of freshly isolated goldfish retinas, after contact with pieces of membrane filter. Likewise, cells were sliced away from the distal side of freshly isolated rat retinas, after these adhered to a membrane filter. The remaining portions of retina were incubated in an enzyme-free, low Ca2+ solution, and triturated. After aliquots of the resulting cell suspension were plated, ganglion cells could be identified by dye retrogradely transported via the optic nerve. These cells showed no obvious morphological degeneration for several days of culture. Perforated-patch whole-cell recordings showed that the goldfish ganglion cells spike tonically in response to depolarizing constant current injections, that these spikes are temporally precise in response to fluctuating current injections, and that the largest voltage-gated Na+ currents of these cells were larger than those of ganglion cells isolated with a neutral protease. PMID:15196824

  14. Dissociation of retinal ganglion cells without enzymes.

    PubMed

    Hayashida, Yuki; Partida, Gloria J; Ishida, Andrew T

    2004-08-15

    We describe here methods for dissociating retinal ganglion cells from adult goldfish and rat without proteolytic enzymes, and show responses of ganglion cells isolated this way to step-wise voltage changes and fluctuating current injections. Taking advantage of the laminar organization of vertebrate retinas, photoreceptors and other cells were lifted away from the distal side of freshly isolated goldfish retinas, after contact with pieces of membrane filter. Likewise, cells were sliced away from the distal side of freshly isolated rat retinas, after these adhered to a membrane filter. The remaining portions of retina were incubated in an enzyme-free, low Ca2+ solution, and triturated. After aliquots of the resulting cell suspension were plated, ganglion cells could be identified by dye retrogradely transported via the optic nerve. These cells showed no obvious morphological degeneration for several days of culture. Perforated-patch whole-cell recordings showed that the goldfish ganglion cells spike tonically in response to depolarizing constant current injections, that these spikes are temporally precise in response to fluctuating current injections, and that the largest voltage-gated Na+ currents of these cells were larger than those of ganglion cells isolated with a neutral protease.

  15. Advances in retinal ganglion cell imaging

    PubMed Central

    Balendra, S I; Normando, E M; Bloom, P A; Cordeiro, M F

    2015-01-01

    Glaucoma is one of the leading causes of blindness worldwide and will affect 79.6 million people worldwide by 2020. It is caused by the progressive loss of retinal ganglion cells (RGCs), predominantly via apoptosis, within the retinal nerve fibre layer and the corresponding loss of axons of the optic nerve head. One of its most devastating features is its late diagnosis and the resulting irreversible visual loss that is often predictable. Current diagnostic tools require significant RGC or functional visual field loss before the threshold for detection of glaucoma may be reached. To propel the efficacy of therapeutics in glaucoma, an earlier diagnostic tool is required. Recent advances in retinal imaging, including optical coherence tomography, confocal scanning laser ophthalmoscopy, and adaptive optics, have propelled both glaucoma research and clinical diagnostics and therapeutics. However, an ideal imaging technique to diagnose and monitor glaucoma would image RGCs non-invasively with high specificity and sensitivity in vivo. It may confirm the presence of healthy RGCs, such as in transgenic models or retrograde labelling, or detect subtle changes in the number of unhealthy or apoptotic RGCs, such as detection of apoptosing retinal cells (DARC). Although many of these advances have not yet been introduced to the clinical arena, their successes in animal studies are enthralling. This review will illustrate the challenges of imaging RGCs, the main retinal imaging modalities, the in vivo techniques to augment these as specific RGC-imaging tools and their potential for translation to the glaucoma clinic. PMID:26293138

  16. Concerted Signaling by Retinal Ganglion Cells

    NASA Astrophysics Data System (ADS)

    Meister, Markus; Lagnado, Leon; Baylor, Denis A.

    1995-11-01

    To analyze the rules that govern communication between eye and brain, visual responses were recorded from an intact salamander retina. Parallel observation of many retinal ganglion cells with a microelectrode array showed that nearby neurons often fired synchronously, with spike delays of less than 10 milliseconds. The frequency of such synchronous spikes exceeded the correlation expected from a shared visual stimulus up to 20-fold. Synchronous firing persisted under a variety of visual stimuli and accounted for the majority of action potentials recorded. Analysis of receptive fields showed that concerted spikes encoded information not carried by individual cells; they may represent symbols in a multineuronal code for vision.

  17. Neurophysiology of central retinal degeneration in cat.

    PubMed

    Levick, W R; Thibos, L N

    1993-01-01

    Receptive fields of ganglion cells have been studied in cats possessing a chronic, arrested lesion of central retinal degeneration. Lesions were characterized by an ophthalmoscopically sharp border separating apparently normal retina from the region of the lesion. Under direct ophthalmoscopic guidance, a succession of recordings was obtained from ganglion cells having cell bodies at various positions relative to the lesion. Cells located more than 1 deg outside the ophthalmoscopic border had normal visual sensitivity as assessed by area-threshold experiments. Inside the lesion cells within 1 deg of the border had reduced sensitivity which often precluded functional classification by the usual visual tests. Ganglion cells located more than 1 deg inside the border of large lesions were blind and some had abnormal patterns of maintained discharge of action potentials. Nevertheless, the antidromic latencies of these blind cells fell into the familiar conduction groups (T1/T2/T3). Receptive-field maps of cells near the border of the lesion often appeared truncated, with the missing portion of the field covered by the lesion. These observations were consistent with the abnormal form of area-threshold curves. Although the responsiveness of cells near the lesion was abnormally low for grating stimuli, cutoff spatial frequency and orientation bias of these cells were within normal limits.

  18. Retinal intrinsic optical signals in a cat model of primary congenital glaucoma.

    PubMed

    Schallek, Jesse B; McLellan, Gillian J; Viswanathan, Suresh; Ts'o, Daniel Y

    2012-04-18

    To examine the impact of reduced inner retinal function and breed on intrinsic optical signals in cats. Retinal intrinsic optical signals were recorded from anesthetized cats with a modified fundus camera. Near infrared light (NIR, 700-900 nm) was used to illuminate the retina while a charge-coupled device (CCD) camera captured the NIR reflectance of the retina. Visible stimuli (540 nm) evoked patterned changes in NIR retinal reflectance. NIR intrinsic signals were compared across three subject groups: two Siamese cats with primary congenital glaucoma (PCG), a control Siamese cat without glaucoma, and a control group of seven normally pigmented cats. Intraocular pressure (IOP), pattern electroretinogram, and optical coherence tomography measurements were evaluated to confirm the inner retinal deficit in PCG cats. Stimulus-evoked, NIR retinal reflectance signals were observed in PCG cats despite severe degeneration of the nerve fiber layer and inner retinal function. The time course, spectral dependence, and spatial profile of signals imaged in PCG cats were similar to signals measured from normal and Siamese control cats. Despite increased IOP, reduced nerve fiber layer thickness and ganglion cell function, intrinsic optical signals persist in cats affected with PCG. The mechanisms giving rise to intrinsic signals remain despite inner retinal damage. Signal strength was reduced in all Siamese cats compared to controls, suggesting that reduced intrinsic signals in PCG cats represent a difference between breeds rather than loss of ganglion cells. These results corroborated previous findings that retinal ganglion cells are not the dominant source of intrinsic optical signals of the retina.

  19. Retinal Intrinsic Optical Signals in a Cat Model of Primary Congenital Glaucoma

    PubMed Central

    Schallek, Jesse B.; McLellan, Gillian J.; Viswanathan, Suresh; Ts'o, Daniel Y.

    2012-01-01

    Purpose. To examine the impact of reduced inner retinal function and breed on intrinsic optical signals in cats. Methods. Retinal intrinsic optical signals were recorded from anesthetized cats with a modified fundus camera. Near infrared light (NIR, 700–900 nm) was used to illuminate the retina while a charge-coupled device (CCD) camera captured the NIR reflectance of the retina. Visible stimuli (540 nm) evoked patterned changes in NIR retinal reflectance. NIR intrinsic signals were compared across three subject groups: two Siamese cats with primary congenital glaucoma (PCG), a control Siamese cat without glaucoma, and a control group of seven normally pigmented cats. Intraocular pressure (IOP), pattern electroretinogram, and optical coherence tomography measurements were evaluated to confirm the inner retinal deficit in PCG cats. Results. Stimulus-evoked, NIR retinal reflectance signals were observed in PCG cats despite severe degeneration of the nerve fiber layer and inner retinal function. The time course, spectral dependence, and spatial profile of signals imaged in PCG cats were similar to signals measured from normal and Siamese control cats. Conclusions. Despite increased IOP, reduced nerve fiber layer thickness and ganglion cell function, intrinsic optical signals persist in cats affected with PCG. The mechanisms giving rise to intrinsic signals remain despite inner retinal damage. Signal strength was reduced in all Siamese cats compared to controls, suggesting that reduced intrinsic signals in PCG cats represent a difference between breeds rather than loss of ganglion cells. These results corroborated previous findings that retinal ganglion cells are not the dominant source of intrinsic optical signals of the retina. PMID:22395886

  20. Evaluating retinal ganglion cell loss and dysfunction.

    PubMed

    Mead, Ben; Tomarev, Stanislav

    2016-10-01

    Retinal ganglion cells (RGC) bear the sole responsibility of propagating visual stimuli to the brain. Their axons, which make up the optic nerve, project from the retina to the brain through the lamina cribrosa and in rodents, decussate almost entirely at the optic chiasm before synapsing at the superior colliculus. For many traumatic and degenerative ocular conditions, the dysfunction and/or loss of RGC is the primary determinant of visual loss and are the measurable endpoints in current research into experimental therapies. To actually measure these endpoints in rodent models, techniques must ascertain both the quantity of surviving RGC and their functional capacity. Quantification techniques include phenotypic markers of RGC, retrogradely transported fluorophores and morphological measurements of retinal thickness whereas functional assessments include electroretinography (flash and pattern) and visual evoked potential. The importance of the accuracy and reliability of these techniques cannot be understated, nor can the relationship between RGC death and dysfunction. The existence of up to 30 types of RGC complicates the measuring process, particularly as these may respond differently to disease and treatment. Since the above techniques may selectively identify and ignore particular subpopulations, their appropriateness as measures of RGC survival and function may be further limited. This review discusses the above techniques in the context of their subtype specificity.

  1. Genetic Networks in Mouse Retinal Ganglion Cells

    PubMed Central

    Struebing, Felix L.; Lee, Richard K.; Williams, Robert W.; Geisert, Eldon E.

    2016-01-01

    Retinal ganglion cells (RGCs) are the output neuron of the eye, transmitting visual information from the retina through the optic nerve to the brain. The importance of RGCs for vision is demonstrated in blinding diseases where RGCs are lost, such as in glaucoma or after optic nerve injury. In the present study, we hypothesize that normal RGC function is transcriptionally regulated. To test our hypothesis, we examine large retinal expression microarray datasets from recombinant inbred mouse strains in GeneNetwork and define transcriptional networks of RGCs and their subtypes. Two major and functionally distinct transcriptional networks centering around Thy1 and Tubb3 (Class III beta-tubulin) were identified. Each network is independently regulated and modulated by unique genomic loci. Meta-analysis of publically available data confirms that RGC subtypes are differentially susceptible to death, with alpha-RGCs and intrinsically photosensitive RGCs (ipRGCs) being less sensitive to cell death than other RGC subtypes in a mouse model of glaucoma. PMID:27733864

  2. Polymodal Sensory Integration in Retinal Ganglion Cells.

    PubMed

    Križaj, David

    2016-01-01

    An animal's ability to perceive the external world is conditioned by its capacity to extract and encode specific features of the visual image. The output of the vertebrate retina is not a simple representation of the 2D visual map generated by photon absorptions in the photoreceptor layer. Rather, spatial, temporal, direction selectivity and color "dimensions" of the original image are distributed in the form of parallel output channels mediated by distinct retinal ganglion cell (RGC) populations. We propose that visual information transmitted to the brain includes additional, light-independent, inputs that reflect the functional states of the retina, anterior eye and the body. These may include the local ion microenvironment, glial metabolism and systemic parameters such as intraocular pressure, temperature and immune activation which act on ion channels that are intrinsic to RGCs. We particularly focus on light-independent mechanical inputs that are associated with physical impact, cell swelling and intraocular pressure as excessive mechanical stimuli lead to the counterintuitive experience of "pressure phosphenes" and/or debilitating blinding disease such as glaucoma and diabetic retinopathy. We point at recently discovered retinal mechanosensitive ion channels as examples through which molecular physiology brings together Greek phenomenology, modern neuroscience and medicine. Thus, RGC output represents a unified picture of the embodied context within which vision takes place.

  3. Phenotypic map of porcine retinal ganglion cells

    PubMed Central

    Veiga-Crespo, Patricia; del Río, Patricia; Blindert, Marcel; Ueffing, Marius; Hauck, Stefanie M.

    2013-01-01

    Purpose Porcine retina is an excellent model for studying diverse retinal processes and diseases. The morphologies of porcine retinal ganglion cells (RGCs) have, however, not yet been described comprehensively. The aim of the present study was to créate a classification of the RGCs using the 1, 1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) tracing method. Methods About 170 RGCs were retrogradely labeled by injecting DiI into the optic nerve of postmortem eyes and statistically analyzed by two different clustering methods: Ward’s algorithm and the K-means clustering. Major axis length of the soma, soma area size, and dendritic field area size were selected as main parameters for cluster classification. Results RGC distribution in clusters was achieved according to their morphological parameters. It was feasible to combine both statistical methods, thereby obtaining a robust clustering distribution. Morphological analysis resulted in a classification of RGCs in three groups according to the soma size and dendritic field: A (large somas and large dendritic fields), B (medium to large somas and medium to large dendritic fields), C (medium to small somas and medium to small dendritic fields). Within groups, fine clustering defined several subgroups according to dendritic arborization and level of stratification. Additionally, cells stratifying in two different levels of the inner plexiform layer were observed within the clusters. Conclusions This comprehensive study of RGC morphologies in the porcine retina provides fundamental knowledge about RGC cell types and provides a basis for functional studies toward selective RGC cell degeneration in retinal disorders. PMID:23687427

  4. Electrophysiological assessment of retinal ganglion cell function

    PubMed Central

    Porciatti, Vittorio

    2015-01-01

    The function of retinal ganglion cells (RGCs) can be non-invasively assessed in experimental and genetic models of glaucoma by means of variants of the ERG technique that emphasize the activity of inner retina neurons. The best understood technique is the Pattern Electroretinogram (PERG) in response to contrast-reversing gratings or checkerboards, which selectively depends on the presence of functional RGCs. In glaucoma models, the PERG can be altered before histological loss of RGCs; PERG alterations may be either reversed with moderate IOP lowering or exacerbated with moderate IOP elevation. Under particular luminance-stimulus conditions, the Flash-ERG displays components that may reflect electrical activity originating in the proximal retina and be altered in some experimental glaucoma models (positive Scotopic Threshold response, pSTR; negative Scotopic Threshold Response, nSTR; Photopic Negative Response, PhNR; Oscillatory Potentials, OPs; multifocal ERG, mfERG). It is not yet known which of these components is most sensitive to glaucomatous damage. Electrophysiological assessment of RGC function appears to be a necessary outcome measure in experimental glaucoma models, which complements structural assessment and may even predict it. Neuroprotective strategies could be tested based on enhancement of baseline electrophysiological function that results in improved RGC survival. The use of electrophysiology in glaucoma models may be facilitated by specifically designed instruments that allow high throughput, robust assessment of electrophysiological function. PMID:25998495

  5. Encoding Visual Information in Retinal Ganglion Cells with Prosthetic Stimulation

    PubMed Central

    Freeman, Daniel K; Rizzo, Joseph F; Fried, Shelley I

    2011-01-01

    Retinal prostheses aim to restore functional vision to those blinded by outer retinal diseases using electric stimulation of surviving retinal neurons. The ability to replicate the spatiotemporal pattern of ganglion cell spike trains present under normal viewing conditions is presumably an important factor for restoring high-quality vision. In order to replicate such activity with a retinal prosthesis, it is important to consider both how visual information is encoded in ganglion cell spike trains, and how retinal neurons respond to electric stimulation. The goal of the current review is to bring together these two concepts in order to guide the development of more effective stimulation strategies. We review the experiments to date that have studied how retinal neurons respond to electric stimulation and discuss these findings in the context of known retinal signaling strategies. The results from such in vitro studies reveal the advantages and disadvantages of activating the ganglion cell directly with the electric stimulus (direct activation) as compared to activation of neurons that are presynaptic to the ganglion cell (indirect activation). While direct activation allows high temporal but low spatial resolution, indirect activation yields improved spatial resolution but poor temporal resolution. Finally, we use knowledge gained from in vitro experiments to infer the patterns of elicited activity in ongoing human trials, providing insights into some of the factors limiting the quality of prosthetic vision. PMID:21593546

  6. THE MODULATORY ROLE OF TAURINE IN RETINAL GANGLION CELLS

    PubMed Central

    Jiang, Zheng; Bulley, Simon; Guzzone, Joseph; Ripps, Harris; Shen, Wen

    2017-01-01

    Taurine (2-aminoethylsuphonic acid) is present in nearly all animal tissues, and is the most abundant free amino acid in muscle, heart, CNS and retina. Although it is known to be a major cytoprotectant and essential for normal retinal development, its role in retinal neurotransmission and modulation is not well understood. We investigated the response of taurine in retinal ganglion cells, and its effect on synaptic transmission between ganglion cells and their pre-synaptic neurons. We find that taurine-elicited currents in ganglion cells could be fully blocked by both strychnine and SR95531, glycine and GABAA receptor antagonists, respectively. This suggests that taurine-activated receptors might share the antagonists with GABA and glycine receptors. The effect of taurine at micromolar concentrations can effectively suppress spontaneous vesicle release from the pre-synaptic neurons, but had limited effects on light-evoked synaptic signals in ganglion cells. We also describe a metabotropic effect of taurine in the suppression of light-evoked response in ganglion cells. Clearly, taurine acts in multiple ways to modulate synaptic signals in retinal output neurons, ganglion cells. PMID:23392924

  7. Ionic channel changes in glaucomatous retinal ganglion cells: multicompartment modeling.

    PubMed

    Maturana, Matias I; Turpin, Andrew; McKendrick, Allison M; Kameneva, Tatiana

    2014-01-01

    This research takes a step towards discovering underlying ionic channel changes in the glaucomatous ganglion cells. Glaucoma is characterized by a gradual death of retinal ganglion cells. In this paper, we propose a hypothesis that the ionic channel concentrations change during the progression of glaucoma. We use computer simulation of a multi-compartment morphologically correct model of a mouse retinal ganglion cell to verify our hypothesis. Using published experimental data, we alter the morphology of healthy ganglion cells to replicate glaucomatous cells. Our results suggest that in glaucomatous cell, the sodium channel concentration decreases in the soma by 30% and by 60% in the dendrites, calcium channel concentration decreases by 10% in all compartments, and leak channel concentration increases by 40% in the soma and by 100% in the dendrites.

  8. Hedgehogs and retinal ganglion cells: organizers of the mammalian retina.

    PubMed

    Dakubo, Gabriel D; Wallace, Valerie A

    2004-03-01

    The mature vertebrate retina develops from a population of multipotential neural progenitor cells that give rise to all of the retinal neurons and one glial cell type. Retinal histogenesis is regulated, in part, by cell extrinsic cues. A growing number of studies now implicate signaling by members of the Hedgehog (Hh) family of morphogens in vertebrate retinal development. In this review we will discuss the role of Hh signals from retinal ganglion cells (RGCs), the projection neurons of the retina, on proliferation, differentiation and lamination in the neural retina.

  9. Directional summation in non-direction selective retinal ganglion cells.

    PubMed

    Abbas, Syed Y; Hamade, Khaldoun C; Yang, Ellen J; Nawy, Scott; Smith, Robert G; Pettit, Diana L

    2013-01-01

    Retinal ganglion cells receive inputs from multiple bipolar cells which must be integrated before a decision to fire is made. Theoretical studies have provided clues about how this integration is accomplished but have not directly determined the rules regulating summation of closely timed inputs along single or multiple dendrites. Here we have examined dendritic summation of multiple inputs along On ganglion cell dendrites in whole mount rat retina. We activated inputs at targeted locations by uncaging glutamate sequentially to generate apparent motion along On ganglion cell dendrites in whole mount retina. Summation was directional and dependent13 on input sequence. Input moving away from the soma (centrifugal) resulted in supralinear summation, while activation sequences moving toward the soma (centripetal) were linear. Enhanced summation for centrifugal activation was robust as it was also observed in cultured retinal ganglion cells. This directional summation was dependent on hyperpolarization activated cyclic nucleotide-gated (HCN) channels as blockade with ZD7288 eliminated directionality. A computational model confirms that activation of HCN channels can override a preference for centripetal summation expected from cell anatomy. This type of direction selectivity could play a role in coding movement similar to the axial selectivity seen in locust ganglion cells which detect looming stimuli. More generally, these results suggest that non-directional retinal ganglion cells can discriminate between input sequences independent of the retina network.

  10. Directional Summation in Non-direction Selective Retinal Ganglion Cells

    PubMed Central

    Abbas, Syed Y.; Hamade, Khaldoun C.; Yang, Ellen J.; Nawy, Scott; Smith, Robert G.; Pettit, Diana L.

    2013-01-01

    Retinal ganglion cells receive inputs from multiple bipolar cells which must be integrated before a decision to fire is made. Theoretical studies have provided clues about how this integration is accomplished but have not directly determined the rules regulating summation of closely timed inputs along single or multiple dendrites. Here we have examined dendritic summation of multiple inputs along On ganglion cell dendrites in whole mount rat retina. We activated inputs at targeted locations by uncaging glutamate sequentially to generate apparent motion along On ganglion cell dendrites in whole mount retina. Summation was directional and dependent13 on input sequence. Input moving away from the soma (centrifugal) resulted in supralinear summation, while activation sequences moving toward the soma (centripetal) were linear. Enhanced summation for centrifugal activation was robust as it was also observed in cultured retinal ganglion cells. This directional summation was dependent on hyperpolarization activated cyclic nucleotide-gated (HCN) channels as blockade with ZD7288 eliminated directionality. A computational model confirms that activation of HCN channels can override a preference for centripetal summation expected from cell anatomy. This type of direction selectivity could play a role in coding movement similar to the axial selectivity seen in locust ganglion cells which detect looming stimuli. More generally, these results suggest that non-directional retinal ganglion cells can discriminate between input sequences independent of the retina network. PMID:23516351

  11. Dorsal raphe nucleus projecting retinal ganglion cells: Why Y cells?

    PubMed Central

    Pickard, Gary E.; So, Kwok-Fai; Pu, Mingliang

    2015-01-01

    Retinal ganglion Y (alpha) cells are found in retinas ranging from frogs to mice to primates. The highly conserved nature of the large, fast conducting retinal Y cell is a testament to its fundamental task, although precisely what this task is remained ill-defined. The recent discovery that Y-alpha retinal ganglion cells send axon collaterals to the serotonergic dorsal raphe nucleus (DRN) in addition to the lateral geniculate nucleus (LGN), medial interlaminar nucleus (MIN), pretectum and the superior colliculus (SC) has offered new insights into the important survival tasks performed by these cells with highly branched axons. We propose that in addition to its role in visual perception, the Y-alpha retinal ganglion cell provides concurrent signals via axon collaterals to the DRN, the major source of serotonergic afferents to the forebrain, to dramatically inhibit 5-HT activity during orientation or alerting/escape responses, which dis-facilitates ongoing tonic motor activity while dis-inhibiting sensory information processing throughout the visual system. The new data provide a fresh view of these evolutionarily old retinal ganglion cells. PMID:26363667

  12. Expression of Aquaporin-6 in Rat Retinal Ganglion Cells.

    PubMed

    Jang, Sun Young; Lee, Eung Suk; Ohn, Young-Hoon; Park, Tae Kwann

    2016-08-01

    Several aquaporins (AQPs) have been identified to be present in the eyes, and it has been suggested that they are involved in the movement of water and small solutes. AQP6, which has low water permeability and transports mainly anions, was recently discovered in the eyes. In the present study, we investigate the localization of AQP6 in the rat retina and show that AQP6 is selectively localized to the ganglion cell layer and the outer plexiform layer. Along with the gradual decrease in retinal ganglion cells after a crushing injury of optic nerve, immunofluorescence signals of AQP6 gradually decreased. Confocal microscope images confirmed AQP6 expression in retinal ganglion cells and Müller cells in vitro. Therefore, AQP6 might participate in water and anion transport in these cells.

  13. Sensitivity of Retinal Ganglion Cell Photoreceptors in Traumatic Brain Injury Patients with Photophobia

    DTIC Science & Technology

    2015-11-01

    AD_________________ Award Number: W81XWH-12-1-0434 TITLE: Sensitivity of retinal ganglion cell photoreceptors in traumatic brain injury patients...1Sep2012 - 31Aug2015 4. TITLE AND SUBTITLE Sensitivity of retinal ganglion cell photoreceptors in traumatic brain 5a. CONTRACT NUMBER W81XWH-12-1... sensitivity of melanopsin-containing retinal ganglion cells in subjects that have had a prior head injury. These intrinsically photosensitive retinal

  14. The circadian response of intrinsically photosensitive retinal ganglion cells.

    PubMed

    Zele, Andrew J; Feigl, Beatrix; Smith, Simon S; Markwell, Emma L

    2011-03-14

    Intrinsically photosensitive retinal ganglion cells (ipRGC) signal environmental light level to the central circadian clock and contribute to the pupil light reflex. It is unknown if ipRGC activity is subject to extrinsic (central) or intrinsic (retinal) network-mediated circadian modulation during light entrainment and phase shifting. Eleven younger persons (18-30 years) with no ophthalmological, medical or sleep disorders participated. The activity of the inner (ipRGC) and outer retina (cone photoreceptors) was assessed hourly using the pupil light reflex during a 24 h period of constant environmental illumination (10 lux). Exogenous circadian cues of activity, sleep, posture, caffeine, ambient temperature, caloric intake and ambient illumination were controlled. Dim-light melatonin onset (DLMO) was determined from salivary melatonin assay at hourly intervals, and participant melatonin onset values were set to 14 h to adjust clock time to circadian time. Here we demonstrate in humans that the ipRGC controlled post-illumination pupil response has a circadian rhythm independent of external light cues. This circadian variation precedes melatonin onset and the minimum ipRGC driven pupil response occurs post melatonin onset. Outer retinal photoreceptor contributions to the inner retinal ipRGC driven post-illumination pupil response also show circadian variation whereas direct outer retinal cone inputs to the pupil light reflex do not, indicating that intrinsically photosensitive (melanopsin) retinal ganglion cells mediate this circadian variation.

  15. Retinal ganglion cell adaptation to small luminance fluctuations.

    PubMed

    Freeman, Daniel K; Graña, Gilberto; Passaglia, Christopher L

    2010-08-01

    To accommodate the wide input range over which the visual system operates within the narrow output range of spiking neurons, the retina adjusts its sensitivity to the mean light level so that retinal ganglion cells can faithfully signal contrast, or relative deviations from the mean luminance. Given the large operating range of the visual system, the majority of work on luminance adaptation has involved logarithmic changes in light level. We report that luminance gain controls are recruited for remarkably small fluctuations in luminance as well. Using spike recordings from the rat optic tract, we show that ganglion cell responses to a brief flash of light are modulated in amplitude by local background fluctuations as little as 15% contrast. The time scale of the gain control is rapid (<125 ms), at least for on cells. The retinal locus of adaptation precedes the ganglion cell spike generator because response gain changes of on cells were uncorrelated with firing rate. The mechanism seems to reside within the inner retinal network and not in the photoreceptors, because the adaptation profiles of on and off cells differed markedly. The response gain changes follow Weber's law, suggesting that network mechanisms of luminance adaptation described in previous work modulates retinal ganglion cell sensitivity, not just when we move between different lighting environments, but also as our eyes scan a visual scene. Finally, we show that response amplitude is uniformly reduced for flashes on a modulated background that has spatial contrast, indicating that another gain control that integrates luminance signals nonlinearly over space operates within the receptive field center of rat ganglion cells.

  16. Retinal ganglion cell topography and spatial resolving power in penguins.

    PubMed

    Coimbra, João Paulo; Nolan, Paul M; Collin, Shaun P; Hart, Nathan S

    2012-01-01

    Penguins are a group of flightless seabirds that exhibit numerous morphological, behavioral and ecological adaptations to their amphibious lifestyle, but little is known about the topographic organization of neurons in their retinas. In this study, we used retinal wholemounts and stereological methods to estimate the total number and topographic distribution of retinal ganglion cells in addition to an anatomical estimate of spatial resolving power in two species of penguins: the little penguin, Eudyptula minor, and the king penguin, Aptenodytes patagonicus. The total number of ganglion cells per retina was approximately 1,200,000 in the little penguin and 1,110,000 in the king penguin. The topographic distribution of retinal ganglion cells in both species revealed the presence of a prominent horizontal visual streak with steeper gradients in the little penguin. The little penguin retinas showed ganglion cell density peaks of 21,867 cells/mm², affording spatial resolution in water of 17.07-17.46 cycles/degree (12.81-13.09 cycles/degree in air). In contrast, the king penguin showed a relatively lower peak density of ganglion cells of 14,222 cells/mm², but--due to its larger eye--slightly higher spatial resolution in water of 20.40 cycles/degree (15.30 cycles/degree in air). In addition, we mapped the distribution of giant ganglion cells in both penguin species using Nissl-stained wholemounts. In both species, topographic mapping of this cell type revealed the presence of an area gigantocellularis with a concentric organization of isodensity contours showing a peak in the far temporal retina of approximately 70 cells/mm² in the little penguin and 39 cells/mm² in the king penguin. Giant ganglion cell densities gradually fall towards the outermost isodensity contours revealing the presence of a vertically organized streak. In the little penguin, we confirmed our cytological characterization of giant ganglion cells using immunohistochemistry for microtubule

  17. Localised retinal vasculitis in cat scratch disease

    PubMed Central

    Jacobs, David Jonathan; Scott, Michele L; Slusher, M Madison

    2009-01-01

    We report an atypical presentation of ocular cat scratch disease (CSD) in an 8-year-old Caucasian male who presented with localised retinal arterial vasculitis and associated retinal oedema. His history of headaches, frequent contact with a kitten and a high Bartonella henslelae titre confirmed the diagnosis of CSD. Over an 18-month follow-up period, his best corrected visual acuity in the affected eye improved from 20/30−2 to 20/25+3 without treatment; however, the affected retinal artery remained sheathed. PMID:21686569

  18. Taurine prevents ultraviolet B induced apoptosis in retinal ganglion cells.

    PubMed

    Dayang, Wu; Dongbo, Pang

    2017-06-07

    Compatible osmolytes accumulation is an active resistance response in retina under ultraviolet radiation and hypertonicity conditions. The purpose of this research is to investigate the protective role of taurine on retina under ultraviolet B radiation. Osmolytes transporters was measured by quantitative realtime PCR. Osmolytes uptake was estimated by radioimmunoassay. Cell viability was caculated by MTT assay. Cell apoptosis was measured by flow cytometry analysis. Hypertonicity accelerated osmolytes uptake into retinal ganglion cells including taurine, betaine and myoinositol. Ultraviolet B radiation increased osmolytes transporter expression and osmolytes uptake. In addition, osmolyte taurine remarkably prevented ultraviolet B radiation induced cell apoptosis in retinal ganglion cells. The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.

  19. The functional diversity of retinal ganglion cells in the mouse.

    PubMed

    Baden, Tom; Berens, Philipp; Franke, Katrin; Román Rosón, Miroslav; Bethge, Matthias; Euler, Thomas

    2016-01-21

    In the vertebrate visual system, all output of the retina is carried by retinal ganglion cells. Each type encodes distinct visual features in parallel for transmission to the brain. How many such 'output channels' exist and what each encodes are areas of intense debate. In the mouse, anatomical estimates range from 15 to 20 channels, and only a handful are functionally understood. By combining two-photon calcium imaging to obtain dense retinal recordings and unsupervised clustering of the resulting sample of more than 11,000 cells, here we show that the mouse retina harbours substantially more than 30 functional output channels. These include all known and several new ganglion cell types, as verified by genetic and anatomical criteria. Therefore, information channels from the mouse eye to the mouse brain are considerably more diverse than shown thus far by anatomical studies, suggesting an encoding strategy resembling that used in state-of-the-art artificial vision systems.

  20. Synchronized Firing among Retinal Ganglion Cells Signals Motion Reversal

    PubMed Central

    Schwartz, Greg; Taylor, Sam; Fisher, Clark; Harris, Rob; Berry, Michael J.

    2011-01-01

    SUMMARY We show that when a moving object suddenly reverses direction, there is a brief, synchronous burst of firing within a population of retinal ganglion cells. This burst can be driven by either the leading or trailing edge of the object. The latency is constant for movement at different speeds, objects of different size, and bright versus dark contrasts. The same ganglion cells that signal a motion reversal also respond to smooth motion. We show that the brain can build a pure reversal detector using only a linear filter that reads out synchrony from a group of ganglion cells. These results indicate that not only can the retina anticipate the location of a smoothly moving object, but that it can also signal violations in its own prediction. We show that the reversal response cannot be explained by models of the classical receptive field and suggest that nonlinear receptive field subunits may be responsible. PMID:17880898

  1. A morphological study of the retinal ganglion cells of the Afghan pika (Ochotona rufescens).

    PubMed

    Akaishi, Y; Uchiyama, H; Ito, H; Shimizu, Y

    1995-03-01

    The distribution and morphology of the retinal ganglion cells was studied in a relative of the rabbit, the Afghan pika. The total number of retinal ganglion cells was approximately 170,000. The total number of optic nerve fibers was between 160,000 and 190,000, corresponding to the total number of retinal ganglion cells. Retinal ganglion cells were found to have a horizontal region of high-density. The maximum density was 5250 cells/mm2. This region was located in the central retina below the optic disc. This area contained numerous closely packed small ganglion cells, while the peripheral retina (especially in the dorsal periphery) contained large ganglion cells more loosely dispersed. The retinal ganglion cells labeled by horseradish peroxidase (HRP) were morphologically classified into three types based on dendritic length and ramification pattern.

  2. Morphology and distribution of neurons in the retinal ganglion cell layer of the adult tammar wallaby--Macropus eugenii.

    PubMed

    Wong, R O; Wye-Dvorak, J; Henry, G H

    1986-11-01

    The morphology of the ganglion cell layer of the adult tammar wallaby has been examined from Nissl-stained retinal flatmounts. From this material, neurons have been classed as ganglion cells or displaced amacrine cells according to the disposition of Nissl substance. A further subdivision of ganglion cells into a separate group of alphalike cells was assisted by determining the range of soma sizes in neurofibrillar-stained flatmounts, a method which, in the cat, has revealed the presence of alpha cells. Isodensity contour maps prepared from the Nissl-stained flatmounts show a well-developed visual streak and an area centralis in the total neuronal population. A similar pattern was also found in the ganglion cells, thus confirming Tancred's (J. Comp. Neurol. 196:585-603, '81) finding, and, as well, in the alphalike ganglion cells and the displaced amacrine cells. The relative proportions of ganglion cells to displaced amacrines (GC:DA) were evaluated from isodensity profiles drawn along and vertical to the visual streak for the two cell types and also from maps showing the variation in the GC:DA ratio throughout the retina. A comparison with results published for other species shows that the visual streak development in the tammar wallaby is consistent with the expectations of the "terrain" theory and that, in its relative proportion of displaced amacrines, the tammar closely resembles the rabbit but contrasts sharply with the cat, which has half as many ganglion cells and three times as many displaced amacrines as the other two species.

  3. Retinal ganglion cell axonal compression by retinal vessels in light-induced retinal degeneration

    PubMed Central

    García-Ayuso, Diego; Salinas-Navarro, Manuel; Agudo-Barriuso, Marta; Alarcón-Martínez, Luis; Vidal-Sanz, Manuel

    2011-01-01

    Purpose To analyze the damage produced by light in mydriatic and miotic albino retinas under two different sources of light. Methods Albino Sprague Dawley female rats were exposed to 3,000 lx during 48 h under two different light sources: linear and circular bulbs. Before exposure, their left pupils were dilated. Before and at different times after light exposure (ALE), electroretinographic signals were recorded. One week before processing, retinal ganglion cells (RGCs) were traced by applying fluorogold on the superior colliculi. Just before processing, some animals were intravenously injected with horseradish peroxidase to analyze retinal vascular leakage. At different times ALE, animals were sacrificed and their retinas dissected as whole mounts or cross-sections. Cross-sections were used to study the retinal degeneration and to detect apoptotic nuclei by the transferase dUTP nick end labeling (TUNEL) technique. Whole mounts were used to analyze vascular leakage; investigate the nerve fiber layer, identified by immunodetection of neurofilaments; and quantify the whole population of RGCs identified by fluorogold tracing and Brn3a immunodetection. With the quantitative data, detailed isodensity maps were generated to study the spatial loss of RGCs. Results Phototoxicity causes an immediate and permanent abolishment of the electroretinographic response. Early ALE, photoreceptors degenerate by apoptosis and this death is more severe in mydriatic conditions and under circular bulbs. Photoreceptor loss starts in an arciform dorsomedial retinal area, but at 3 months ALE has spread to the whole retina and there are no differences related to either pupil dilation or light source. Three months ALE, RGC axons show distorted trajectories and abnormal expression of neurofilaments. Six months or more ALE, there is significant death of RGCs caused by axonal strangulation by displaced inner retinal vessels. Topography of the surviving RGCs shows that their loss is not uniform

  4. High speed coding for velocity by archerfish retinal ganglion cells.

    PubMed

    Kretschmer, Viola; Kretschmer, Friedrich; Ahlers, Malte T; Ammermüller, Josef

    2012-06-18

    Archerfish show very short behavioural latencies in response to falling prey. This raises the question, which response parameters of retinal ganglion cells to moving stimuli are best suited for fast coding of stimulus speed and direction. We compared stimulus reconstruction quality based on the ganglion cell response parameters latency, first interspike interval, and rate. For stimulus reconstruction of moving stimuli using latency was superior to using the other stimulus parameters. This was true for absolute latency, with respect to stimulus onset, as well as for relative latency, with respect to population response onset. Iteratively increasing the number of cells used for reconstruction decreased the calculated error close to zero. Latency is the fastest response parameter available to the brain. Therefore, latency coding is best suited for high speed coding of moving objects. The quantitative data of this study are in good accordance with previously published behavioural response latencies.

  5. Taurine Provides Neuroprotection against Retinal Ganglion Cell Degeneration

    PubMed Central

    Froger, Nicolas; Cadetti, Lucia; Lorach, Henri; Martins, Joao; Bemelmans, Alexis-Pierre; Dubus, Elisabeth; Degardin, Julie; Pain, Dorothée; Forster, Valérie; Chicaud, Laurent; Ivkovic, Ivana; Simonutti, Manuel; Fouquet, Stéphane; Jammoul, Firas; Léveillard, Thierry; Benosman, Ryad; Sahel, José-Alain; Picaud, Serge

    2012-01-01

    Retinal ganglion cell (RGC) degeneration occurs in numerous retinal diseases leading to blindness, either as a primary process like in glaucoma, or secondary to photoreceptor loss. However, no commercial drug is yet directly targeting RGCs for their neuroprotection. In the 70s, taurine, a small sulfonic acid provided by nutrition, was found to be essential for the survival of photoreceptors, but this dependence was not related to any retinal disease. More recently, taurine deprivation was incriminated in the retinal toxicity of an antiepileptic drug. We demonstrate here that taurine can improve RGC survival in culture or in different animal models of RGC degeneration. Taurine effect on RGC survival was assessed in vitro on primary pure RCG cultures under serum-deprivation conditions, and on NMDA-treated retinal explants from adult rats. In vivo, taurine was administered through the drinking water in two glaucomatous animal models (DBA/2J mice and rats with vein occlusion) and in a model of Retinitis pigmentosa with secondary RGC degeneration (P23H rats). After a 6-day incubation, 1 mM taurine significantly enhanced RGCs survival (+68%), whereas control RGCs were cultured in a taurine-free medium, containing all natural amino-acids. This effect was found to rely on taurine-uptake by RGCs. Furthermore taurine (1 mM) partly prevented NMDA-induced RGC excitotoxicity. Finally, taurine supplementation increased RGC densities both in DBA/2J mice, in rats with vein occlusion and in P23H rats by contrast to controls drinking taurine-free water. This study indicates that enriched taurine nutrition can directly promote RGC survival through RGC intracellular pathways. It provides evidence that taurine can positively interfere with retinal degenerative diseases. PMID:23115615

  6. Taurine provides neuroprotection against retinal ganglion cell degeneration.

    PubMed

    Froger, Nicolas; Cadetti, Lucia; Lorach, Henri; Martins, Joao; Bemelmans, Alexis-Pierre; Dubus, Elisabeth; Degardin, Julie; Pain, Dorothée; Forster, Valérie; Chicaud, Laurent; Ivkovic, Ivana; Simonutti, Manuel; Fouquet, Stéphane; Jammoul, Firas; Léveillard, Thierry; Benosman, Ryad; Sahel, José-Alain; Picaud, Serge

    2012-01-01

    Retinal ganglion cell (RGC) degeneration occurs in numerous retinal diseases leading to blindness, either as a primary process like in glaucoma, or secondary to photoreceptor loss. However, no commercial drug is yet directly targeting RGCs for their neuroprotection. In the 70s, taurine, a small sulfonic acid provided by nutrition, was found to be essential for the survival of photoreceptors, but this dependence was not related to any retinal disease. More recently, taurine deprivation was incriminated in the retinal toxicity of an antiepileptic drug. We demonstrate here that taurine can improve RGC survival in culture or in different animal models of RGC degeneration. Taurine effect on RGC survival was assessed in vitro on primary pure RCG cultures under serum-deprivation conditions, and on NMDA-treated retinal explants from adult rats. In vivo, taurine was administered through the drinking water in two glaucomatous animal models (DBA/2J mice and rats with vein occlusion) and in a model of Retinitis pigmentosa with secondary RGC degeneration (P23H rats). After a 6-day incubation, 1 mM taurine significantly enhanced RGCs survival (+68%), whereas control RGCs were cultured in a taurine-free medium, containing all natural amino-acids. This effect was found to rely on taurine-uptake by RGCs. Furthermore taurine (1 mM) partly prevented NMDA-induced RGC excitotoxicity. Finally, taurine supplementation increased RGC densities both in DBA/2J mice, in rats with vein occlusion and in P23H rats by contrast to controls drinking taurine-free water. This study indicates that enriched taurine nutrition can directly promote RGC survival through RGC intracellular pathways. It provides evidence that taurine can positively interfere with retinal degenerative diseases.

  7. Interphase gap decreases electrical stimulation threshold of retinal ganglion cells.

    PubMed

    Weitz, A C; Behrend, M R; Humayun, M S; Chow, R H; Weiland, J D

    2011-01-01

    The most common electrical stimulation pulse used in retinal implants is a symmetric biphasic current pulse. Prior electrophysiological studies in peripheral nerve have shown that adding an interphase gap (IPG) between the two phases makes stimulation more efficient. We investigated the effect of IPG duration on retinal ganglion cell (RGC) electrical threshold. We used calcium imaging to measure the activity of RGCs in isolated retina in response to electrical stimulation. By varying IPG duration, we were able to examine the effect of duration on threshold. We further studied this effect by simulating RGC behavior with a Hodgkin-Huxley-type model. Our results indicate that the threshold for electrical activation of RGCs can be reduced by increasing the length of the IPG.

  8. Retinal Ganglion Cell Topography and Retinal Resolution in the Baikal Seal (Pusa sibirica).

    PubMed

    Mass, Alla M; Supin, Alexander Y

    2016-01-01

    The total number, size, topographic distribution, and cell density of ganglion cells were studied in retinal wholemounts of Baikal seals (Pusa sibirica). The ganglion cell size varied from 10 to 38 μm. A distinct cell group consisted of large ganglion cells of more than 30 μm in diameter. The topographic distribution of ganglion cells showed a definite area of high cell density similar to the area centralis of terrestrial carnivores. This area was located approximately 6-7 mm dorsotemporally of the geometric center of the wholemount. In this area, the peak cell densities in two wholemounts were 3,800 and 3,400 cells/mm2 (mean 3,600 cells/mm2). With a posterior nodal distance of 24 mm (underwater), this density corresponds to 631 cells/square degree. These values predict a retinal resolution of 2.4' in water and 3.0' in air. The topographic distribution of large cells featured the highest density in the same location as the total ganglion cell population.

  9. Diverse Central Projection Patterns of Retinal Ganglion Cells.

    PubMed

    Martersteck, Emily M; Hirokawa, Karla E; Evarts, Mariah; Bernard, Amy; Duan, Xin; Li, Yang; Ng, Lydia; Oh, Seung W; Ouellette, Benjamin; Royall, Joshua J; Stoecklin, Michelle; Wang, Quanxin; Zeng, Hongkui; Sanes, Joshua R; Harris, Julie A

    2017-02-21

    Understanding how >30 types of retinal ganglion cells (RGCs) in the mouse retina each contribute to visual processing in the brain will require more tools that label and manipulate specific RGCs. We screened and analyzed retinal expression of Cre recombinase using 88 transgenic driver lines. In many lines, Cre was expressed in multiple RGC types and retinal cell classes, but several exhibited more selective expression. We comprehensively mapped central projections from RGCs labeled in 26 Cre lines using viral tracers, high-throughput imaging, and a data processing pipeline. We identified over 50 retinorecipient regions and present a quantitative retina-to-brain connectivity map, enabling comparisons of target-specificity across lines. Projections to two major central targets were notably correlated: RGCs projecting to the outer shell or core regions of the lateral geniculate projected to superficial or deep layers within the superior colliculus, respectively. Retinal images and projection data are available online at http://connectivity.brain-map.org.

  10. Modeling the variability of firing rate of retinal ganglion cells.

    PubMed

    Levine, M W

    1992-12-01

    Impulse trains simulating the maintained discharges of retinal ganglion cells were generated by digital realizations of the integrate-and-fire model. If the mean rate were set by a "bias" level added to "noise," the variability of firing would be related to the mean firing rate as an inverse square root law; the maintained discharges of retinal ganglion cells deviate systematically from such a relationship. A more realistic relationship can be obtained if the integrate-and-fire mechanism is "leaky"; with this refinement, the integrate-and-fire model captures the essential features of the data. However, the model shows that the distribution of intervals is insensitive to that of the underlying variability. The leakage time constant, threshold, and distribution of the noise are confounded, rendering the model unspecifiable. Another aspect of variability is presented by the variance of responses to repeated discrete stimuli. The variance of response rate increases with the mean response amplitude; the nature of that relationship depends on the duration of the periods in which the response is sampled. These results have defied explanation. But if it is assumed that variability depends on mean rate in the way observed for maintained discharges, the variability of responses to abrupt changes in lighting can be predicted from the observed mean responses. The parameters that provide the best fits for the variability of responses also provide a reasonable fit to the variability of maintained discharges.

  11. Dynamic Characteristics of Retinal Ganglion Cell Responses in Goldfish

    PubMed Central

    Schellart, Nico A. M.; Spekreijse, Henk

    1972-01-01

    A cross-correlation technique has been applied to quantify the dependence of the dynamic characteristics of retinal ganglion cell responses in goldfish on intensity, wavelength, spatial configuration, and spot size. Both theoretical and experimental evidence justify the use of the cross-correlation procedure which allows the completion of rather extensive measurements in a relatively short time. The findings indicate the following. (a) The shape of the amplitude characteristics depends on the energy per unit of time (power) falling within the center of a receptive field rather than on the intensity of the stimulus spot. For spot diameters of up to 1 mm, identical amplitude characteristics can be obtained by interchanging area and intensity. Therefore the receptor processes do not contribute to the change in the amplitude characteristics as a function of the power of the stimulus light. (b) For high frequencies the amplitude characteristics obtained as a function of power join together in a common envelope if plotted on an absolute sensitivity scale. For spontaneous ganglion cells this envelope holds over a range of three log units and the shape is identical for central and peripheral processes. (c) The amplitude characteristics of the central and peripheral processes converging to a ganglion cell are identical, irrespective of the sign (on or off) and the spectral coding of the response. Therefore we have no evidence for interneurons in the goldfish retina unique to the periphery of the receptive field. PMID:5007262

  12. Oligomeric proanthocyanidin protects retinal ganglion cells against oxidative stress-induced apoptosis

    PubMed Central

    Wang, Hui; Zhang, Chanjuan; Lu, Dan; Shu, Xiaoming; Zhu, Lihong; Qi, Renbing; So, Kwok-Fai; Lu, Daxiang; Xu, Ying

    2013-01-01

    The death of retinal ganglion cells is a hallmark of many optic neurodegenerative diseases such as glaucoma and retinopathy. Oxidative stress is one of the major reasons to cause the cell death. Oligomeric proanthocyanidin has many health beneficial effects including antioxidative and neuroprotective actions. Here we tested whether oligomeric proanthocyanidin may protect retinal ganglion cells against oxidative stress induced-apoptosis in vitro. Retinal ganglion cells were treated with hydrogen peroxide with or without oligomeric proanthocyanidin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that treating retinal ganglion cell line RGC-5 cells with 20 μmol/L oligomeric proanthocyanidin significantly decreased the hydrogen peroxide (H2O2) induced death. Results of flow cytometry and Hoechst staining demonstrated that the death of RGC-5 cells was mainly caused by cell apoptosis. We further found that expression of pro-apoptotic Bax and caspase-3 were significantly decreased while anti-apoptotic Bcl-2 was greatly increased in H2O2 damaged RGC-5 cells with oligomeric proanthocyanidin by western blot assay. Furthermore, in retinal explant culture, the number of surviving retinal ganglion cells in H2O2-damaged retinal ganglion cells with oligomeric proanthocyanidin was significantly increased. Our studies thus demonstrate that oligomeric proanthocyanidin can protect oxidative stress-injured retinal ganglion cells by inhibiting apoptotic process. PMID:25206541

  13. Time-Lapse Retinal Ganglion Cell Dendritic Field Degeneration Imaged in Organotypic Retinal Explant Culture

    PubMed Central

    Johnson, Thomas V.; Oglesby, Ericka N.; Steinhart, Matthew R.; Cone-Kimball, Elizabeth; Jefferys, Joan; Quigley, Harry A.

    2016-01-01

    Purpose To develop an ex vivo organotypic retinal explant culture system suitable for multiple time-point imaging of retinal ganglion cell (RGC) dendritic arbors over a period of 1 week, and capable of detecting dendrite neuroprotection conferred by experimental treatments. Methods Thy1-YFP mouse retinas were explanted and maintained in organotypic culture. Retinal ganglion cell dendritic arbors were imaged repeatedly using confocal laser scanning microscopy. Maximal projection z-stacks were traced by two masked investigators and dendritic fields were analyzed for characteristics including branch number, size, and complexity. One group of explants was treated with brain derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) added to the culture media. Changes in individual dendritic fields over time were detected using pair-wise comparison testing. Results Retinal ganglion cells in mouse retinal explant culture began to degenerate after 3 days with 52.4% surviving at 7 days. Dendritic field parameters showed minimal change over 8 hours in culture. Intra- and interobserver measurements of dendrite characteristics were strongly correlated (Spearman rank correlations consistently > 0.80). Statistically significant (P < 0.001) dendritic tree degeneration was detected following 7 days in culture including: 40% to 50% decreases in number of branch segments, number of junctions, number of terminal branches, and total branch length. Scholl analyses similarly demonstrated a significant decrease in dendritic field complexity. Treatment of explants with BDNF+CNTF significantly attenuated dendritic field degeneration. Conclusions Retinal explant culture of Thy1-YFP tissue provides a useful model for time-lapse imaging of RGC dendritic field degeneration over a course of several days, and is capable of detecting neuroprotective amelioration of dendritic pruning within individual RGCs. PMID:26811145

  14. Melanopsin retinal ganglion cell loss in Alzheimer disease

    PubMed Central

    Ross‐Cisneros, Fred N.; Koronyo, Yosef; Hannibal, Jens; Gallassi, Roberto; Cantalupo, Gaetano; Sambati, Luisa; Pan, Billy X.; Tozer, Kevin R.; Barboni, Piero; Provini, Federica; Avanzini, Pietro; Carbonelli, Michele; Pelosi, Annalisa; Chui, Helena; Liguori, Rocco; Baruzzi, Agostino; Koronyo‐Hamaoui, Maya; Sadun, Alfredo A.; Carelli, Valerio

    2015-01-01

    Objective Melanopsin retinal ganglion cells (mRGCs) are photoreceptors driving circadian photoentrainment, and circadian dysfunction characterizes Alzheimer disease (AD). We investigated mRGCs in AD, hypothesizing that they contribute to circadian dysfunction. Methods We assessed retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) in 21 mild‐moderate AD patients, and in a subgroup of 16 we evaluated rest–activity circadian rhythm by actigraphy. We studied postmortem mRGCs by immunohistochemistry in retinas, and axons in optic nerve cross‐sections of 14 neuropathologically confirmed AD patients. We coimmunostained for retinal amyloid β (Aβ) deposition and melanopsin to locate mRGCs. All AD cohorts were compared with age‐matched controls. Results We demonstrated an age‐related optic neuropathy in AD by OCT, with a significant reduction of RNFL thickness (p = 0.038), more evident in the superior quadrant (p = 0.006). Axonal loss was confirmed in postmortem AD optic nerves. Abnormal circadian function characterized only a subgroup of AD patients. Sleep efficiency was significantly reduced in AD patients (p = 0.001). We also found a significant loss of mRGCs in postmortem AD retinal specimens (p = 0.003) across all ages and abnormal mRGC dendritic morphology and size (p = 0.003). In flat‐mounted AD retinas, Aβ accumulation was remarkably evident inside and around mRGCs. Interpretation We show variable degrees of rest–activity circadian dysfunction in AD patients. We also demonstrate age‐related loss of optic nerve axons and specifically mRGC loss and pathology in postmortem AD retinal specimens, associated with Aβ deposition. These results all support the concept that mRGC degeneration is a contributor to circadian rhythm dysfunction in AD. ANN NEUROL 2016;79:90–109 PMID:26505992

  15. Cannabinoids modulate spontaneous synaptic activity in retinal ganglion cells.

    PubMed

    Middleton, T P; Protti, D A

    2011-09-01

    The endocannabinoid (ECB) system has been found throughout the central nervous system and modulates cell excitability in various forms of short-term plasticity. ECBs and their receptors have also been localized to all retinal cells, and cannabinoid receptor activation has been shown to alter voltage-dependent conductances in several different retinal cell types, suggesting a possible role for cannabinoids in retinal processing. Their effects on synaptic transmission in the mammalian retina, however, have not been previously investigated. Here, we show that exogenous cannabinoids alter spontaneous synaptic transmission onto retinal ganglion cells (RGCs). Using whole-cell voltage-clamp recordings in whole-mount retinas, we measured spontaneous postsynaptic currents (SPSCs) in RGCs in adult and young (P14-P21) mice. We found that the addition of an exogenous cannabinoid agonist, WIN55212-2 (5 μM), caused a significant reversible reduction in the frequency of SPSCs. This change, however, did not alter the kinetics of the SPSCs, indicating a presynaptic locus of action. Using blockers to isolate inhibitory or excitatory currents, we found that cannabinoids significantly reduced the release probability of both GABA and glutamate, respectively. While the addition of cannabinoids reduced the frequency of both GABAergic and glutamatergic SPSCs in both young and adult mice, we found that the largest effect was on GABA-mediated currents in young mice. These results suggest that the ECB system may potentially be involved in the modulation of signal transmission in the retina. Furthermore, they suggest that it might play a role in the developmental maturation of synaptic circuits, and that exogenous cannabinoids are likely able to disrupt retinal processing and consequently alter vision.

  16. Inhibition of BDNF-AS Provides Neuroprotection for Retinal Ganglion Cells against Ischemic Injury

    PubMed Central

    Xu, Lifang; Zhang, Ziyin; Xie, Tianhua; Zhang, Xiaoyang; Dai, Tu

    2016-01-01

    Background: Brain-derived neurotrophic factor (BDNF) protects retinal ganglion cells against ischemia in ocular degenerative diseases. We aimed to determine the effect of BDNF-AS on the ischemic injury of retinal ganglion cells. Methods: The levels of BDNF and BDNF-AS were measured in retinal ganglion cells subjected to oxygen and glucose deprivation. The lentiviral vectors were constructed to either overexpress or knock out BDNF-AS. The luciferase reporter gene assay was used to determine whether BDNF-AS could target its seed sequence on BDNF mRNA. The methyl thiazolyl tetrazolium assay was used to determine cell viability, and TUNEL staining was used for cell apoptosis. Results: The levels of BDNF-AS were negatively correlated with BDNF in ischemic retinal ganglion cells. BDNF-AS directly targeted its complementary sequences on BDNF mRNA. BDNF-AS regulated the expression of BDNF and its related genes in retinal ganglion cells. Down-regulation of BDNF-AS increased cell viability and decreased the number of TUNEL-positive retinal ganglion cells under oxygen and glucose deprivation conditions. Conclusion: Inhibition of BDNF-AS protected retinal ganglion cells against ischemia by increasing the levels of BDNF. PMID:27935942

  17. Connexin43 mimetic peptide reduces vascular leak and retinal ganglion cell death following retinal ischaemia.

    PubMed

    Danesh-Meyer, Helen V; Kerr, Nathan M; Zhang, Jie; Eady, Elizabeth K; O'Carroll, Simon J; Nicholson, Louise F B; Johnson, Cameron S; Green, Colin R

    2012-02-01

    Connexin43 gap junction protein is expressed in astrocytes and the vascular endothelium in the central nervous system. It is upregulated following central nervous system injury and is recognized as playing an important role in modulating the extent of damage. Studies that have transiently blocked connexin43 in spinal cord injury and central nervous system epileptic models have reported neuronal rescue. The purpose of this study was to investigate neuronal rescue following retinal ischaemia-reperfusion by transiently blocking connexin43 activity using a connexin43 mimetic peptide. A further aim was to evaluate the effect of transiently blocking connexin43 on vascular permeability as this is known to increase following central nervous system ischaemia. Adult male Wistar rats were exposed to 60 min of retinal ischaemia. Treatment groups consisted of no treatment, connexin43 mimetic peptide and scrambled peptide. Retinas were then evaluated at 1-2, 4, 8 and 24 h, and 7 and 21 days post-ischaemia. Evans blue dye leak from retinal blood vessels was used to assess vascular leakage. Blood vessel integrity was examined using isolectin-B4 labelling. Connexin43 levels and astrocyte activation (glial fibrillary acidic protein) were assessed using immunohistochemistry and western blot analysis. Retinal whole mounts and retinal ganglion cell counts were used to quantify neurodegeneration. An in vitro cell culture model of endothelial cell ischaemia was used to assess the effect of connexin43 mimetic peptide on endothelial cell survival and connexin43 hemichannel opening using propidium iodide dye uptake. We found that retinal ischaemia-reperfusion induced significant vascular leakage and disruption at 1-2, 4 and 24 h following injury with a peak at 4 h. Connexin43 immunoreactivity was significantly increased at 1-2, 4, 8 and 24 h post ischaemia-reperfusion injury co-localizing with activated astrocytes, Muller cells and vascular endothelial cells. Connexin43 mimetic peptide

  18. Photon capture and signalling by melanopsin retinal ganglion cells

    PubMed Central

    Do, Michael Tri H.; Kang, Shin H.; Xue, Tian; Zhong, Haining; Liao, Hsi-Wen; Bergles, Dwight E.; Yau, King-Wai

    2009-01-01

    A subset of retinal ganglion cells has recently been discovered to be intrinsically photosensitive, with melanopsin as the pigment. These cells project primarily to brain centers for non-image-forming visual functions such as the pupillary light reflex and circadian photoentrainment. How well they signal intrinsic light absorption to drive behavior remains unclear. Here we report fundamental parameters governing their intrinsic light responses and associated spike generation. The membrane density of melanopsin is 104-fold lower than that of rod and cone pigments, resulting in a very low photon-catch and a phototransducing role only in relatively bright light. Nonetheless, each captured photon elicits a large and extraordinarily prolonged response, with a unique shape among known photoreceptors. Remarkably, like rods, these cells are capable of signalling single-photon absorption. A flash causing a few hundred isomerized melanopsin molecules in a retina is sufficient for reaching threshold for the pupillary light reflex. PMID:19118382

  19. Gene therapy for retinal ganglion cell neuroprotection in glaucoma.

    PubMed

    Wilson, A M; Di Polo, A

    2012-02-01

    Glaucoma is the leading cause of irreversible blindness worldwide. The primary cause of glaucoma is not known, but several risk factors have been identified, including elevated intraocular pressure and age. Loss of vision in glaucoma is caused by the death of retinal ganglion cells (RGCs), the neurons that convey visual information from the retina to the brain. Therapeutic strategies aimed at delaying or halting RGC loss, known as neuroprotection, would be valuable to save vision in glaucoma. In this review, we discuss the significant progress that has been made in the use of gene therapy to understand mechanisms underlying RGC degeneration and to promote the survival of these neurons in experimental models of optic nerve injury.

  20. Photon capture and signalling by melanopsin retinal ganglion cells.

    PubMed

    Do, Michael Tri H; Kang, Shin H; Xue, Tian; Zhong, Haining; Liao, Hsi-Wen; Bergles, Dwight E; Yau, King-Wai

    2009-01-15

    A subset of retinal ganglion cells has recently been discovered to be intrinsically photosensitive, with melanopsin as the pigment. These cells project primarily to brain centres for non-image-forming visual functions such as the pupillary light reflex and circadian photoentrainment. How well they signal intrinsic light absorption to drive behaviour remains unclear. Here we report fundamental parameters governing their intrinsic light responses and associated spike generation. The membrane density of melanopsin is 10(4)-fold lower than that of rod and cone pigments, resulting in a very low photon catch and a phototransducing role only in relatively bright light. Nonetheless, each captured photon elicits a large and extraordinarily prolonged response, with a unique shape among known photoreceptors. Notably, like rods, these cells are capable of signalling single-photon absorption. A flash causing a few hundred isomerized melanopsin molecules in a retina is sufficient for reaching threshold for the pupillary light reflex.

  1. FTY720 protects retinal ganglion cells in experimental glaucoma.

    PubMed

    You, Yuyi; Gupta, Vivek K; Li, Jonathan C; Al-Adawy, Nadia; Klistorner, Alexander; Graham, Stuart L

    2014-04-17

    To investigate the neuroprotective effects of sphingosine-1-phosphate (S1P) analogue fingolimod (FTY720) in experimental glaucoma in rats. A unilateral chronic ocular hypertensive model was established by injections of microbeads into the anterior eye chamber of adult Sprague-Dawley rats. Fingolimod was administered to one group of rats intraperitoneally every week for 3 months. The scotopic threshold response (STR) was recorded to assess the function of the inner retina. Changes in cell density in the ganglion cell layer (GCL) were evaluated by hematoxylin and eosin staining on retinal sections and axonal count of the optic nerve was performed using Bielschowsky's silver staining. Effects of drug treatment on activation of Akt and Erk1/2 were evaluated using Western blotting by assessing phosphorylation levels of these proteins. The expression of S1P receptors in the optic nerve head region was also evaluated using Western blotting and immunohistochemistry. Administration of FTY720 reduced the loss of STR amplitude in glaucomatous eyes (P < 0.05). Counting and plotting the cell numbers/axonal density showed significant neural preservation in the GCL and the optic nerve (P < 0.05). An increased phosphorylation level of Akt and Erk1/2 following FTY720 administration was observed. Both S1P1 and S1P5 receptors were found to be expressed in the retina and the expression of S1P1R was upregulated in experimentally-induced glaucoma. This study demonstrates, for the first time, that FTY720 could act as a neuroprotective agent to protect retinal ganglion cells in experimental glaucoma. Administration of this drug significantly reduces the structural and functional loss of the inner retina elicited indicating that it may potentially be used to attenuate neuronal loss and optic nerve damage in glaucomatous patients. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  2. Morphological properties of mouse retinal ganglion cells during postnatal development.

    PubMed

    Coombs, Julie L; Van Der List, Deborah; Chalupa, Leo M

    2007-08-20

    Quantitative methods were used to assess dendritic stratification and other structural features of developing mouse retinal ganglion cells from birth to after eye opening. Cells were labeled by transgenic expression of yellow fluorescent protein, DiOlistics or diffusion of DiI, and subsequently imaged in three dimensions on a confocal microscope followed by morphometric analysis of 13 different structural properties. At postnatal day 1 (P1), the dendrites of all cells ramified across the vertical extent of the inner plexiform layer (IPL). By P3/4, dendrites were largely confined to different strata of the IPL. The stratification of dendrites initially reflected a retraction of widely ramifying dendritic processes, but for the most part this was due to the subsequent vertical expansion of the IPL. By P8, distinct cell classes could be recognized, although these had not yet attained adult-like properties. The structural features differentiating cell classes were found to follow three different developmental trends. The mean values of one set of morphological parameters were essentially unchanged throughout postnatal development; another set of measures showed a rapid rise with age to adult values; and a third set of measures first increased with age and later decreased, with the regressive events initiated around the time of eye opening. These findings suggest that the morphological development of retinal ganglion cells is regulated by diverse factors operating during different but overlapping time periods. Our results also suggest that dendritic stratification may be more highly specified in the developing mammalian retina than has been previously realized.

  3. Inhibitory masking controls the threshold sensitivity of retinal ganglion cells.

    PubMed

    Pan, Feng; Toychiev, Abduqodir; Zhang, Yi; Atlasz, Tamas; Ramakrishnan, Hariharasubramanian; Roy, Kaushambi; Völgyi, Béla; Akopian, Abram; Bloomfield, Stewart A

    2016-11-15

    Retinal ganglion cells (RGCs) in dark-adapted retinas show a range of threshold sensitivities spanning ∼3 log units of illuminance. Here, we show that the different threshold sensitivities of RGCs reflect an inhibitory mechanism that masks inputs from certain rod pathways. The masking inhibition is subserved by GABAC receptors, probably on bipolar cell axon terminals. The GABAergic masking inhibition appears independent of dopaminergic circuitry that has been shown also to affect RGC sensitivity. The results indicate a novel mechanism whereby inhibition controls the sensitivity of different cohorts of RGCs. This can limit and thereby ensure that appropriate signals are carried centrally in scotopic conditions when sensitivity rather than acuity is crucial. The responses of rod photoreceptors, which subserve dim light vision, are carried through the retina by three independent pathways. These pathways carry signals with largely different sensitivities. Retinal ganglion cells (RGCs), the output neurons of the retina, show a wide range of sensitivities in the same dark-adapted conditions, suggesting a divergence of the rod pathways. However, this organization is not supported by the known synaptic morphology of the retina. Here, we tested an alternative idea that the rod pathways converge onto single RGCs, but inhibitory circuits selectively mask signals so that one pathway predominates. Indeed, we found that application of GABA receptor blockers increased the sensitivity of most RGCs by unmasking rod signals, which were suppressed. Our results indicate that inhibition controls the threshold responses of RGCs under dim ambient light. This mechanism can ensure that appropriate signals cross the bottleneck of the optic nerve in changing stimulus conditions. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  4. Retrograde degeneration of retinal ganglion cells in homonymous hemianopsia

    PubMed Central

    Herro, Angela M; Lam, Byron L

    2015-01-01

    Background The aim of this study was to demonstrate the relationship between topographic reduction in macular ganglion cell complex (GCC) thickness as detected with spectral-domain optical coherence tomography and visual field defects caused by ischemic occipital cortical injury. Methods This study was a retrospective review of all patients who presented to our eye institution between January 2012 and July 2014 with visual field defects secondary to ischemic cortical injury. The visual field defect pattern and mean deviation were analyzed. Retinal nerve fiber layer (RNFL) and macular GCC were both assessed with spectral-domain optical coherence tomography. Patients with any ocular pathology that could affect these measurements were excluded. The topographic relationship of visual field defect to reduction in GCC was specifically analyzed. Results Nine patients met the inclusion criteria. Their average age was 65 (57–73) years; eight were men and six had right hemianopsias. The laterality of the visual field defect was used to assign an affected and unaffected side of analysis for RNFL and GCC layer thickness. A right hemianopsia meant that the nasal fibers of the right eye and temporal fibers of the left eye were assigned as the “affected side”, and the temporal fibers of the right eye and nasal fibers of the left eye were assigned as “unaffected”. There was no statistically significant difference between affected and unaffected RNFL. However, there was a significant difference in GCC layer reduction between the affected and unaffected sides (P=0.029). Conclusion There is evidence of retrograde trans-synaptic retinal ganglion cell loss in patients with homonymous hemianopsias from cortical visual impairment. This relationship is reflected in thinning of the GCC and maintains the topographic relationship of the visual field defect. PMID:26089638

  5. Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): calculating visual resolution.

    PubMed

    Pettigrew, John D; Manger, Paul R

    2008-01-01

    A single right retina from a black rhinoceros was whole mounted, stained and analyzed to determine the visual resolution of the rhinoceros, an animal with reputedly poor eyesight. A range of small (15-microm diameter) to large (100-microm diameter) ganglion cell types was seen across the retina. We observed two regions of high density of retinal ganglion cells at either end of a long, but thin, horizontal streak. The temporal specialization, which receives light from the anterior visual field, exhibited a ganglion cell density of approximately 2000/mm2, while the nasal specialization exhibited a density of approximately 1500/mm2. The retina exhibited a ganglion cell density bias toward the upper half, especially so, the upper temporal quadrant, indicating that the rhinoceros would be processing visual information from the visual field below the anterior horizon for the most part. Our calculations indicate that the rhinoceros has a visual resolution of 6 cycles/degree. While this resolution is one-tenth that of humans (60 cycles/deg) and less than that of the domestic cat (9 cycles/deg), it is comparable to that of the rabbit (6 cycles/deg), and exceeds that seen in a variety of other mammals including seals, dolphins, microbats, and rats. Thus, the reputation of the rhinoceros as a myopic, weakly visual animal is not supported by our observations of the retina. We calculate that the black rhinoceros could readily distinguish a 30 cm wide human at a distance of around 200 m given the appropriate visual background.

  6. Specific inhibition of TRPV4 enhances retinal ganglion cell survival in adult porcine retinal explants.

    PubMed

    Taylor, Linnéa; Arnér, Karin; Ghosh, Fredrik

    2017-01-01

    Signaling through the polymodal cation channel Transient Receptor Potential Vanilloid 4 (TRPV4) has been implicated in retinal neuronal degeneration. To further outline the involvement of this channel in this process, we here explore modulation of Transient Receptor Potential Vanilloid 4 (TRPV4) activity on neuronal health and glial activation in an in vitro model of retinal degeneration. For this purpose, adult porcine retinal explants were cultured using a previously established standard protocol for up to 5 days with specific TRPV4 agonist GSK1016790A (GSK), or specific antagonist RN-1734, or culture medium only. Glial and neuronal cell health were evaluated by a battery of immunohistochemical markers, as well as morphological staining. Specific inhibition of TRPV4 by RN-1734 significantly enhanced ganglion cell survival, improved the maintenance of the retinal laminar architecture, reduced apoptotic cell death and attenuated the gliotic response as well as preserved the expression of TRPV4 in the plexiform layers and ganglion cells. In contrast, culture controls, as well as specimens treated with GSK, displayed rapid remodeling and neurodegeneration as well as a downregulation of TRPV4 and the Müller cell homeostatic mediator glutamine synthetase. Our results indicate that TRPV4 signaling is an important contributor to the retinal degeneration in this model, affecting neuronal cell health and glial homeostasis. The finding that pharmacological inhibition of the receptor significantly attenuates neuronal degeneration and gliosis in vitro, suggests that TRPV4 signaling may be an interesting pharmaceutical target to explore for treatment of retinal degenerative disease.

  7. Chapter XX: POLYMODAL SENSORY INTEGRATION IN RETINAL GANGLION CELLS

    PubMed Central

    Križaj, David

    2016-01-01

    An animal's ability to perceive the external world is conditioned by its capacity to extract and encode specific features of the visual image. The output of the vertebrate retina is not a simple representation of the 2D visual map generated by photon absorptions in the photoreceptor layer. Rather, spatial, temporal, direction selectivity and color “dimensions” of the original image are distributed in the form of parallel output channels mediated by distinct retinal ganglion cell (RGC) populations. We propose that visual information transmitted to the brain includes additional, light-independent, inputs that reflect the functional states of the retina, anterior eye and the body. These may include the local ion microenvironment, glial metabolism and systemic parameters such as intraocular pressure, temperature and immune activation which act on ion channels that are intrinsic to RGCs. We particularly focus on light-independent mechanical inputs that are associated with physical impact, cell swelling and intraocular pressure as excessive mechanical stimuli lead to the counterintuitive experience of “pressure phosphenes” and/or debilitating blinding disease such as glaucoma and diabetic retinopathy. We point at recently discovered retinal mechanosensitive ion channels as examples through which molecular physiology brings together Greek phenomenology, modern neuroscience and medicine. Thus, RGC output represents a unified picture of the embodied context within which vision takes place. PMID:26427477

  8. Enriched retinal ganglion cells derived from human embryonic stem cells

    PubMed Central

    Gill, Katherine P.; Hung, Sandy S. C.; Sharov, Alexei; Lo, Camden Y.; Needham, Karina; Lidgerwood, Grace E.; Jackson, Stacey; Crombie, Duncan E.; Nayagam, Bryony A.; Cook, Anthony L.; Hewitt, Alex W.; Pébay, Alice; Wong, Raymond C. B.

    2016-01-01

    Optic neuropathies are characterised by a loss of retinal ganglion cells (RGCs) that lead to vision impairment. Development of cell therapy requires a better understanding of the signals that direct stem cells into RGCs. Human embryonic stem cells (hESCs) represent an unlimited cellular source for generation of human RGCs in vitro. In this study, we present a 45-day protocol that utilises magnetic activated cell sorting to generate enriched population of RGCs via stepwise retinal differentiation using hESCs. We performed an extensive characterization of these stem cell-derived RGCs by examining the gene and protein expressions of a panel of neural/RGC markers. Furthermore, whole transcriptome analysis demonstrated similarity of the hESC-derived RGCs to human adult RGCs. The enriched hESC-RGCs possess long axons, functional electrophysiological profiles and axonal transport of mitochondria, suggestive of maturity. In summary, this RGC differentiation protocol can generate an enriched population of functional RGCs from hESCs, allowing future studies on disease modeling of optic neuropathies and development of cell therapies. PMID:27506453

  9. Selective retinal ganglion cell loss in familial dysautonomia.

    PubMed

    Mendoza-Santiesteban, Carlos E; Hedges Iii, Thomas R; Norcliffe-Kaufmann, Lucy; Axelrod, Felicia; Kaufmann, Horacio

    2014-04-01

    To define the retinal phenotype of subjects with familial dysautonomia (FD). A cross-sectional study was carried out in 90 subjects divided in three groups of 30 each (FD subjects, asymptomatic carriers and controls). The study was developed at the Dysautonomia Center, New York University Medical Center. All subjects underwent spectral domain optical coherence tomography (OCT) and full neuro-ophthalmic examinations. In a subset of affected subjects, visual evoked potentials and microperimetry were also obtained. We compared the retinal nerve fiber layer (RNFL) thickness from OCT between the three groups. OCT showed loss of the RNFL in all FD subjects predominantly in the maculopapillary region (63 % temporally, p < 0.0001; and 21 % nasally, p < 0.005). RNFL loss was greatest in older FD subjects and was associated with decreased visual acuity and color vision, central visual field defects, temporal optic nerve pallor, and delayed visual evoked potentials. Asymptomatic carriers of the FD gene mutation all had thinner RNFL (12 % globally, p < 0.005). OCT and clinical neuro-ophthalmological findings suggest that maculopapillary ganglion cells are primarily affected in FD subjects, leading to a specific optic nerve damage that closely resembles mitochondrial optic neuropathies. This raises the possibility that reduced IKAP levels may affect mitochondrial proteins and their function in the nervous system, particularly in the retina.

  10. Nicotinic Antagonists Enhance Process Outgrowth by Rat Retinal Ganglion Cells in Culture

    NASA Astrophysics Data System (ADS)

    Lipton, Stuart A.; Frosch, Matthew P.; Phillips, Micheal D.; Tauck, David L.; Aizenman, Elias

    1988-03-01

    Functional nicotinic cholinergic receptors are found on mammalian retinal ganglion cell neurons in culture. The neurotransmitter acetylcholine (ACh) can be detected in the medium of many of these retinal cultures, after release presumably from the choline acetyltransferase-positive amacrine cells. The postsynaptic effect of endogenous or applied ACh on the ganglion cells can be blocked with specific nicotinic antagonists. Here it is shown that within 24 hours of producing such a pharmacologic blockade, the retinal ganglion cells begin to sprout or regenerate neuronal processes. Thus, the growth-enhancing effect of nicotinic antagonists may be due to the removal of inhibition to growth by tonic levels of ACh present in the culture medium. Since there is a spontaneous leak of ACh in the intact retina, the effects of nicotinic cholinergic drugs on process outgrowth in culture may reflect a normal control mechanism for growth or regeneration of retinal ganglion cell processes that is exerted by ACh in vivo.

  11. An open-source computational tool to automatically quantify immunolabeled retinal ganglion cells.

    PubMed

    Dordea, Ana C; Bray, Mark-Anthony; Allen, Kaitlin; Logan, David J; Fei, Fei; Malhotra, Rajeev; Gregory, Meredith S; Carpenter, Anne E; Buys, Emmanuel S

    2016-06-01

    A fully automated and robust method was developed to quantify β-III-tubulin-stained retinal ganglion cells, combining computational recognition of individual cells by CellProfiler and a machine-learning tool to teach phenotypic classification of the retinal ganglion cells by CellProfiler Analyst. In animal models of glaucoma, quantification of immunolabeled retinal ganglion cells is currently performed manually and remains time-consuming. Using this automated method, quantifications of retinal ganglion cell images were accelerated tenfold: 1800 images were counted in 3 h using our automated method, while manual counting of the same images took 72 h. This new method was validated in an established murine model of microbead-induced optic neuropathy. The use of the publicly available software and the method's user-friendly design allows this technique to be easily implemented in any laboratory. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Retinal Waves Modulate an Intraretinal Circuit of Intrinsically Photosensitive Retinal Ganglion Cells

    PubMed Central

    Arroyo, David A.; Kirkby, Lowry A.

    2016-01-01

    Before the maturation of rod and cone photoreceptors, the developing retina relies on light detection by intrinsically photosensitive retinal ganglion cells (ipRGCs) to drive early light-dependent behaviors. ipRGCs are output neurons of the retina; however, they also form functional microcircuits within the retina itself. Whether ipRGC microcircuits exist during development and whether they influence early light detection remain unknown. Here, we investigate the neural circuit that underlies the ipRGC-driven light response in developing mice. We use a combination of calcium imaging, tracer coupling, and electrophysiology experiments to show that ipRGCs form extensive gap junction networks that strongly contribute to the overall light response of the developing retina. Interestingly, we found that gap junction coupling was modulated by spontaneous retinal waves, such that acute blockade of waves dramatically increased the extent of coupling and hence increased the number of light-responsive neurons. Moreover, using an optical sensor, we found that this wave-dependent modulation of coupling is driven by dopamine that is phasically released by retinal waves. Our results demonstrate that ipRGCs form gap junction microcircuits during development that are modulated by retinal waves; these circuits determine the extent of the light response and thus potentially impact the processing of early visual information and light-dependent developmental functions. SIGNIFICANCE STATEMENT Light-dependent functions in early development are mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). Here we show that ipRGCs form an extensive gap junction network with other retinal neurons, including other ipRGCs, which shapes the retina's overall light response. Blocking cholinergic retinal waves, which are the primary source of neural activity before maturation of photoreceptors, increased the extent of ipRGC gap junction networks, thus increasing the number of light

  13. Retinal Waves Modulate an Intraretinal Circuit of Intrinsically Photosensitive Retinal Ganglion Cells.

    PubMed

    Arroyo, David A; Kirkby, Lowry A; Feller, Marla B

    2016-06-29

    Before the maturation of rod and cone photoreceptors, the developing retina relies on light detection by intrinsically photosensitive retinal ganglion cells (ipRGCs) to drive early light-dependent behaviors. ipRGCs are output neurons of the retina; however, they also form functional microcircuits within the retina itself. Whether ipRGC microcircuits exist during development and whether they influence early light detection remain unknown. Here, we investigate the neural circuit that underlies the ipRGC-driven light response in developing mice. We use a combination of calcium imaging, tracer coupling, and electrophysiology experiments to show that ipRGCs form extensive gap junction networks that strongly contribute to the overall light response of the developing retina. Interestingly, we found that gap junction coupling was modulated by spontaneous retinal waves, such that acute blockade of waves dramatically increased the extent of coupling and hence increased the number of light-responsive neurons. Moreover, using an optical sensor, we found that this wave-dependent modulation of coupling is driven by dopamine that is phasically released by retinal waves. Our results demonstrate that ipRGCs form gap junction microcircuits during development that are modulated by retinal waves; these circuits determine the extent of the light response and thus potentially impact the processing of early visual information and light-dependent developmental functions. Light-dependent functions in early development are mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). Here we show that ipRGCs form an extensive gap junction network with other retinal neurons, including other ipRGCs, which shapes the retina's overall light response. Blocking cholinergic retinal waves, which are the primary source of neural activity before maturation of photoreceptors, increased the extent of ipRGC gap junction networks, thus increasing the number of light-responsive cells. We

  14. Distribution and morphology of retinal ganglion cells in the Japanese quail.

    PubMed

    Ikushima, M; Watanabe, M; Ito, H

    1986-06-25

    A ganglion cell density map was produced from the Nissl-stained retinal whole mount of the Japanese quail. Ganglion cell density diminished nearly concentrically from the central area toward the retinal periphery. The mean soma area of ganglion cells in isodensity zones increased as the cell density decreased. The histograms of soma areas in each zone indicated that a population of small-sized ganglion cells persists into the peripheral retina. The total number of ganglion cells was estimated at about 2.0 million. Electron microscopic examination of the optic nerve revealed thin unmyelinated axons to comprise 69% of the total fiber count (about 2.0 million). Since there was no discrepancy between both the total numbers of neurons in the ganglion cell layer and optic nerve fibers, it is inferred that displaced amacrine cells are few, if any. The spectrum in optic nerve fiber diameter showed a unimodal skewed distribution quite similar to the histogram of soma areas of ganglion cells in the whole retina. This suggests a close correlation between soma areas and axon diameters. Retinal ganglion cells filled from the optic nerve with horseradish peroxidase were classified into 7 types according to such morphological characteristics as size, shape and location of the soma, as well as dendritic arborization pattern. Taking into account areal ranges of somata of each cell type, it can be assumed that most of the ganglion cells in the whole retinal ganglion cell layer are composed of type I, II and III cells, and that the population of uniformly small-sized ganglion cells corresponds to type I cells and is an origin of unmyelinated axons in the optic nerve.

  15. Macro- and microstructure of the superior cervical ganglion in dogs, cats and horses during maturation.

    PubMed

    Fioretto, Emerson Ticona; de Abreu, Rogério Navarro; Castro, Marcelo Fernandes de Souza; Guidi, Wanderley Lima; Ribeiro, Antonio Augusto Coppi Maciel

    2007-01-01

    The superior cervical ganglion (SCG) provides sympathetic input to the head and neck, its relation with mandible, submandibular glands, eyes (second and third order control) and pineal gland being demonstrated in laboratory animals. In addition, the SCG's role in some neuropathies can be clearly seen in Horner's syndrome. In spite of several studies published involving rats and mice, there is little morphological descriptive and comparative data of SCG from large mammals. Thus, we investigated the SCG's macro- and microstructural organization in medium (dogs and cats) and large animals (horses) during a very specific period of the post-natal development, namely maturation (from young to adults). The SCG of dogs, cats and horses were spindle shaped and located deeply into the bifurcation of the common carotid artery, close to the distal vagus ganglion and more related to the internal carotid artery in dogs and horses, and to the occipital artery in cats. As to macromorphometrical data, that is ganglion length, there was a 23.6% increase from young to adult dogs, a 1.8% increase from young to adult cats and finally a 34% increase from young to adult horses. Histologically, the SCG's microstructure was quite similar between young and adult animals and among the 3 species. The SCG was divided into distinct compartments (ganglion units) by capsular septa of connective tissue. Inside each ganglion unit the most prominent cellular elements were ganglion neurons, glial cells and small intensely fluorescent cells, comprising the ganglion's morphological triad. Given this morphological arrangement, that is a summation of all ganglion units, SCG from dogs, cats and horses are better characterized as a ganglion complex rather than following the classical ganglion concept. During maturation (from young to adults) there was a 32.7% increase in the SCG's connective capsule in dogs, a 25.8% increase in cats and a 33.2% increase in horses. There was an age-related increase in the

  16. Homotypic constraints dominate positioning of on- and off-center beta retinal ganglion cells

    PubMed Central

    EGLEN, STEPHEN J.; DIGGLE, PETER J.; TROY, JOHN B.

    2006-01-01

    Beta retinal ganglion cells (RGCs) of the cat are classified as either on-center or off-center, according to their response to light. The cell bodies of these on- and off-center RGCs are spatially distributed into regular patterns, known as retinal mosaics. In this paper, we investigate the nature of spatial dependencies between the positioning of on- and off-center RGCs by analysing maps of RGCs and simulating these patterns. We introduce principled approaches to parameter estimation, along with likelihood-based techniques to evaluate different hypotheses. Spatial constraints between cells within-type and between-type are assumed to be controlled by two univariate interaction functions and one bivariate interaction function. By making different assumptions on the shape of the bivariate interaction function, we can compare the hypothesis of statistical independence against the alternative hypothesis of functional independence, where interactions between type are limited to preventing somal overlap. Our findings suggest that the mosaics of on- and off-center beta RGCs are likely to be generated assuming functional independence between the two types. By contrast, allowing a more general form of bivariate interaction function did not improve the likelihood of generating the observed maps. On- and off-center beta RGCs are therefore likely to be positioned subject only to homotypic constraints and the physical constraint that no two somas of opposite type can occupy the same position. PMID:16469193

  17. The molecular basis of retinal ganglion cell death in glaucoma.

    PubMed

    Almasieh, Mohammadali; Wilson, Ariel M; Morquette, Barbara; Cueva Vargas, Jorge Luis; Di Polo, Adriana

    2012-03-01

    Glaucoma is a group of diseases characterized by progressive optic nerve degeneration that results in visual field loss and irreversible blindness. A crucial element in the pathophysiology of all forms of glaucoma is the death of retinal ganglion cells (RGCs), a population of CNS neurons with their soma in the inner retina and axons in the optic nerve. Strategies that delay or halt RGC loss have been recognized as potentially beneficial to preserve vision in glaucoma; however, the success of these approaches depends on an in-depth understanding of the mechanisms that lead to RGC dysfunction and death. In recent years, there has been an exponential increase in valuable information regarding the molecular basis of RGC death stemming from animal models of acute and chronic optic nerve injury as well as experimental glaucoma. The emerging landscape is complex and points at a variety of molecular signals - acting alone or in cooperation - to promote RGC death. These include: axonal transport failure, neurotrophic factor deprivation, toxic pro-neurotrophins, activation of intrinsic and extrinsic apoptotic signals, mitochondrial dysfunction, excitotoxic damage, oxidative stress, misbehaving reactive glia and loss of synaptic connectivity. Collectively, this body of work has considerably updated and expanded our view of how RGCs might die in glaucoma and has revealed novel, potential targets for neuroprotection. Copyright © 2011. Published by Elsevier Ltd.

  18. Polarization and orientation of retinal ganglion cells in vivo

    PubMed Central

    Zolessi, Flavio R; Poggi, Lucia; Wilkinson, Christopher J; Chien, Chi-Bin; Harris, William A

    2006-01-01

    In the absence of external cues, neurons in vitro polarize by using intrinsic mechanisms. For example, cultured hippocampal neurons extend arbitrarily oriented neurites and then one of these, usually the one nearest the centrosome, begins to grow more quickly than the others. This neurite becomes the axon as it accumulates molecular components of the apical junctional complex. All the other neurites become dendrites. It is unclear, however, whether neurons in vivo, which differentiate within a polarized epithelium, break symmetry by using similar intrinsic mechanisms. To investigate this, we use four-dimensional microscopy of developing retinal ganglion cells (RGCs) in live zebrafish embryos. We find that the situation is indeed very different in vivo, where axons emerge directly from uniformly polarized cells in the absence of other neurites. In vivo, moreover, components of the apical complex do not localize to the emerging axon, nor does the centrosome predict the site of axon emergence. Mosaic analysis in four dimensions, using mutants in which neuroepithelial polarity is disrupted, indicates that extrinsic factors such as access to the basal lamina are critical for normal axon emergence from RGCs in vivo. PMID:17147778

  19. Effects of betaxolol on light responses and membrane conductance in retinal ganglion cells.

    PubMed

    Gross, R L; Hensley, S H; Gao, F; Yang, X L; Dai, S C; Wu, S M

    2000-03-01

    To examine the physiological effects of betaxolol, a beta1-adrenergic receptor blocker commonly used in the treatment of glaucoma, on retinal ganglion cells and to evaluate its potential to elicit responses consistent with a neuroprotective agent against ganglion cell degeneration. Single-unit extracellular recording, electroretinogram (ERG), intracellular and whole-cell patch-clamp recording techniques were made from flatmounted, isolated retina, superfused eyecup, and living retinal slice preparations of the larval tiger salamander. Bath application of 20 microM betaxolol reduced the glutamate-induced increase of spontaneous spike rate in retinal ganglion cell by approximately 30%. The glutamate-induced postsynaptic current recorded under voltage-clamp conditions was reduced by 50 microM betaxolol, and the difference current-voltage (I-V) relation (I(Control)-I(betaxolol)) was N-shaped and AP5-sensitive, characteristic of N-methyl-D-aspartate receptor-mediated current. Application of 50 microM betaxolol reversibly reduced the voltage-gated sodium and calcium currents by approximately one third of their peak amplitudes. The times-to-action of betaxolol on ganglion cells are long (15-35 minutes for 20-50 microM betaxolol), indicative of modulation through slow biochemical cascades. Betaxolol, up to 100 microM, exerted no effects on horizontal cells or the ERG, suggesting that the primary actions of this beta1 blocker are restricted to retinal ganglion cells. These physiological experiments provide supporting evidence that betaxolol acts in a manner consistent with preventing retinal ganglion cell death induced by elevated extracellular glutamate or by increased spontaneous spike rates under pathologic conditions. The physiological actions of betaxolol lead to reducing neurotoxic effects in ganglion cells, which are the most susceptible retinal neurons to glutamate-induced damages under ischemic and glaucomatous conditions. Therefore, betaxolol has the potential to

  20. Impairment of intrinsically photosensitive retinal ganglion cells associated with late stages of retinal degeneration.

    PubMed

    Esquiva, Gema; Lax, Pedro; Cuenca, Nicolás

    2013-07-10

    To evaluate quantitative and qualitative age-related changes in intrinsically photosensitive melanopsin-containing retinal ganglion cells (ipRGCs) in transgenic P23H rats, an animal model of autosomal dominant retinitis pigmentosa (RP) was examined. ipRGC density, morphology, and integrity were characterized by immunohistochemistry in retinas extracted from P23H and Sprague-Dawley (SD) rats aged 4, 12, and 18 months. Differences between SD and P23H rats throughout the experimental stages, as well as the interactions among them, were morphologically evaluated. In rat retinas, we have identified ipRGCs with dendrites stratifying in either the outer margin (M1) or inner side (M2) of the inner plexiform layer, and in both the outer and inner plexuses (M3). A small group of M1 cells had their somas located in the inner nuclear layer (M1d). In SD rats, ipRGCs showed no significant changes associated with age, in terms of either mean cell density or the morphologic parameters analyzed. However, the mean density of ipRGCs in P23H rats fell by approximately 67% between 4 and 18 months of age. Moreover, ipRGCs in these animals showed a progressive age-dependent decrease in the dendritic area, the number of branch points and terminal neurite tips per cell, and the Sholl area. In the P23H rat model of retinitis pigmentosa, density, wholeness, and dendritic arborization of melanopsin-containing ganglion cells decrease in advanced stages of the degenerative disease.

  1. A freely available semi-automated method for quantifying retinal ganglion cells in entire retinal flatmounts.

    PubMed

    Geeraerts, E; Dekeyster, E; Gaublomme, D; Salinas-Navarro, M; De Groef, L; Moons, L

    2016-06-01

    Glaucomatous optic neuropathies are characterized by progressive loss of retinal ganglion cells (RGCs), the neurons that connect the eye to the brain. Quantification of these RGCs is a cornerstone in experimental optic neuropathy research and commonly performed via manually quantifying parts of the retina. However, this is a time-consuming process subject to inter- and intra-observer variability. Here we present a freely available ImageJ script to semi-automatically quantify RGCs in entire retinal flatmounts after immunostaining for the RGC-specific transcription factor Brn3a. The blob-like signal of Brn3a-immunopositive RGCs is enhanced via eigenvalues of the Hessian matrix and the resulting local maxima are counted as RGCs. After the user has outlined the retinal flatmount area, the total RGC number and retinal area are reported and an isodensity map, showing the RGC density distribution across the retina, is created. The semi-automated quantification shows a very strong correlation (Pearson's r ≥ 0.99) with manual counts for both widefield and confocal images, thereby validating the data generated via the developed script. Moreover, application of this method in established glaucomatous optic neuropathy models such as N-methyl-D-aspartate-induced excitotoxicity, optic nerve crush and laser-induced ocular hypertension revealed RGC loss conform with literature. Compared to manual counting, the described automated quantification method is faster and shows user-independent consistency. Furthermore, as the script detects the RGC number in entire retinal flatmounts, the method allows detection of regional differences in RGC density. As such, it can help advance research investigating the degenerative mechanisms of glaucomatous optic neuropathies and the effectiveness of new neuroprotective treatments. Because the script is flexible and easy to optimize due to a low number of critical parameters, it can potentially be applied in combination with other tissues or

  2. Changes in ganglion cell physiology during retinal degeneration influence excitability by prosthetic electrodes

    PubMed Central

    Cho, Alice; Ratliff, Charles; Sampath, Alapakkam; Weiland, James

    2016-01-01

    Objective Here we investigate ganglion cell physiology in healthy and degenerating retina to test its influence on threshold to electrical stimulation. Approach Age-related Macular Degeneration and Retinitis Pigmentosa cause blindness via outer retinal degeneration. Inner retinal pathways that transmit visual information to the central brain remain intact, so direct electrical stimulation from prosthetic devices offers the possibility for visual restoration. Since inner retinal physiology changes during degeneration, we characterize physiological properties and responses to electrical stimulation in retinal ganglion cells of both wild type mice and the rd10 mouse model of retinal degeneration. Main results Our aggregate results support previous observations that elevated thresholds characterize diseased retinas. However, a physiology-driven classification scheme reveals distinct sub-populations of ganglion cells with thresholds either normal or strongly elevated compared to wild-type. When these populations are combined, only a weakly elevated threshold with large variance is observed. The cells with normal threshold are more depolarized at rest and exhibit periodic oscillations. Significance During degeneration, physiological changes in retinal ganglion cells affect the threshold stimulation currents required to evoke action potentials. PMID:26905177

  3. Selective degeneration of the parvocellular-projecting retinal ganglion cells in a New World monkey, Saimiri sciureus.

    PubMed

    Lynch, J J; Eskin, T A; Merigan, W H

    1989-10-16

    Selective degeneration of retinal ganglion cells projecting to parvocellular layers of the dorsal lateral geniculate nucleus (LGN) was observed in squirrel monkeys (Saimiri sciureus) exposed to a range of doses of acrylamide monomer. Similar acrylamide-induced neuronal loss has previously been reported in parvocellular-projecting ganglion cells of macaques, but no such selective degeneration has been found in acrylamide-dosed rats, squirrels, rabbits or cats. The extent of ganglion cell loss observed in the present study suggests that in the squirrel monkey, as in the macaque, a majority of ganglion cells project to parvocellular layers of the LGN. The locus of optic tract degeneration suggests that the squirrel monkey parvocellular pathway passes in dorsolateral optic tract, as does that of the macaque. Patterns of decreases in cytochrome oxidase activity confirm that, in both of these primates, geniculocortical pathways driven by these vulnerable neurons project to cortical layers 4A and 4C beta. These results suggest close parallels in the neuroanatomical projections and toxic vulnerability of the parvocellular-projecting pathway in New and Old World monkeys. They indicate that acrylamide intoxication can be used to selectively damage this pathway in order to study the functional roles of parallel visual pathways in both New and Old World monkeys.

  4. Methane rescues retinal ganglion cells and limits retinal mitochondrial dysfunction following optic nerve crush.

    PubMed

    Wang, Ruobing; Sun, Qinglei; Xia, Fangzhou; Chen, Zeli; Wu, Jiangchun; Zhang, Yuelu; Xu, Jiajun; Liu, Lin

    2017-06-01

    Secondary degeneration is a common event in traumatic central nervous system disorders, which involves neuronal apoptosis and mitochondrial dysfunction. Exogenous methane exerts the therapeutic effects in many organ injury. Our study aims to investigate the potential neuroprotection of methane in a rat model of optic nerve crush (ONC). Adult male Sprague-Dawley rats were subjected to ONC and administrated intraperitoneally with methane-saturated or normal saline (10 ml/kg) once per day for one week after ONC. The retinal ganglion cells (RGCs) density was assessed by hematoxylin and eosin staining and Fluoro-Gold retrogradely labeling. Visual function was evaluated by flash visual evoked potentials (FVEP). The retinal apoptosis was measured by terminal-deoxy-transferase-mediated dUTP nick end labeling (TUNEL) assay and the expression of apoptosis-related factors, such as phosphorylated Bcl-2-associated death promoter (pBAD), phosphorylated glycogen synthase kinase-3β (pGSK-3β), Bcl-2 associated X protein (Bax) and Bcl-2 extra large (Bcl-xL). Retinal mitochondrial function was assessed by the mRNA expressions of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), the mitochondrial DNA (mtDNA) copy number, citrate synthase activity and ATP content. Methane treatment significantly improved the RGC loss and visual dysfunction following ONC. As expected, methane also remarkably inhibited the retinal neural apoptosis, such as the fewer TUNEL-positive cells in ganglion cell layer, accompanied by the up-regulations of anti-apoptotic factors (pGSK-3β, pBAD, Bcl-xL) and the down-regulation of pro-apoptotic factor (Bax). Furthermore, methane treatment suppressed up-regulations of critical mitochondrial components (PGC-1α, NRF1 and TFAM) mRNA and mtDNA copy number, as well as improved the reduction of functional mitochondria markers, including citrate synthase

  5. Isolation of rod and cone contributions to cat ganglion cells by a method of light exchange.

    PubMed

    Rodieck, R W; Rushton, W A

    1976-01-01

    1. The great majority of cat retinal ganglion cells are known to receive signals from rods and from a single (green) cone type. The centre region of the receptive fields of these cells was stimulated by a spot that changed back and forth from orange to white. By adjusting the intensity of the white spot relative to that of the orange a condition could be established at which the photon-catch rate of the rods remained unchanged during the orange-white exchange. At this intensity setting, termed the rod isolept, rods are thus unstimulated by the exchange, however intense, and the ganglion-cell response was found to be due entirely to the green cones. At another intensity setting of the white spot relative to the orange (cone isolept), the photon catch of the green cones remained unchanged during the exchange and ganglion-cell responses were found to arise entirely from the rods. 2. A neutral wedge in the combined exchange beam (but not in the steady background that covered the whole receptive field) regulated the size of the exchange stimulus and thus the magnitude of the ganglion-cell discharge heard from a loud speaker to the exchange. Exchange threshold was the wedge setting at which this change in firing rate could only just be heard. 3. At the cone isolept, cones remain unstimulated however intense the exchange stimulus, and the rod increment threshold curve was determined over its full range from absolute threshold up to saturation. Likewise, at the rod isolept, the cone increment threshold curve was determined over the same intensity range as for the rods. Rod saturation was found to occur at the point where the cone increment threshold curve began to rise from its absolute threshold level toward its Weber region. 4. The exchange approach also enabled both rod and cone dark-adaptation curves following a strong bleaching exposure to be obtained in the same experiment by moving successively between the cone and rod isolepts. At the cone isolept the time course

  6. Estimating the Rate of Retinal Ganglion Cell Loss in Glaucoma

    PubMed Central

    Medeiros, Felipe A.; Zangwill, Linda M.; Anderson, Douglas R.; Liebmann, Jeffrey M.; Girkin, Christopher A; Harwerth, Ronald S.; Fredette, Marie-Josée; Weinreb, Robert N.

    2013-01-01

    Purpose To present and evaluate a new method of estimating rates of retinal ganglion cell (RGC) loss in glaucoma by combining structural and functional measurements. Design Observational cohort study Methods The study included 213 eyes of 213 glaucoma patients followed for an average of 4.5±0.8 years with standard automated perimetry (SAP) visual fields and optical coherence tomography (OCT). A control group of 33 eyes of 33 glaucoma patients had repeated tests over a short period of time to test the specificity of the method. An additional group of 52 eyes from 52 healthy subjects followed for an average of 4.0±0.7 years was used to estimate age-related losses of RGCs. Estimates of RGC counts were obtained from SAP and OCT and a weighted average was used to obtain a final estimate of the number of RGCs for each eye. The rate of RGC loss was calculated for each eye using linear regression. Progression was defined by a statistically significant slope faster than the age-expected loss of RGCs. Results From the 213 eyes, 47 (22.1%) showed rates of RGC loss that were faster than the age-expected decline. A larger proportion of glaucomatous eyes showed progression based on rates of RGC loss than based on isolated parameters from SAP (8.5%) or OCT (14.6%; P<0.01), while maintaining similar specificities in the stable group. Conclusion The rate of RGC loss estimated from combining structure and function performed better than either isolated structural or functional measures for detecting progressive glaucomatous damage. PMID:22840484

  7. Signalling by melanopsin (OPN4) expressing photosensitive retinal ganglion cells

    PubMed Central

    Hughes, S; Jagannath, A; Rodgers, J; Hankins, M W; Peirson, S N; Foster, R G

    2016-01-01

    Over the past two decades there have been significant advances in our understanding of both the anatomy and function of the melanopsin system. It has become clear that rather than acting as a simple irradiance detector the melanopsin system is in fact far more complicated. The range of behavioural systems known to be influenced by melanopsin activity is increasing with time, and it is now clear that melanopsin contributes not only to multiple non-image forming systems but also has a role in visual pathways. How melanopsin is capable of driving so many different behaviours is unclear, but recent evidence suggests that the answer may lie in the diversity of melanopsin light responses and the functional specialisation of photosensitive retinal ganglion cell (pRGC) subtypes. In this review, we shall overview the current understanding of the melanopsin system, and evaluate the evidence for the hypothesis that individual pRGC subtypes not only perform specific roles, but are functionally specialised to do so. We conclude that while, currently, the available data somewhat support this hypothesis, we currently lack the necessary detail to fully understand how the functional diversity of pRGC subtypes correlates with different behavioural responses, and ultimately why such complexity is required within the melanopsin system. What we are lacking is a cohesive understanding of how light responses differ between the pRGC subtypes (based not only on anatomical classification but also based on their site of innervation); how these diverse light responses are generated, and most importantly how these responses relate to the physiological functions they underpin. PMID:26768919

  8. Ketorolac Administration Attenuates Retinal Ganglion Cell Death After Axonal Injury.

    PubMed

    Nadal-Nicolás, Francisco M; Rodriguez-Villagra, Esther; Bravo-Osuna, Irene; Sobrado-Calvo, Paloma; Molina-Martínez, Irene; Villegas-Pérez, Maria Paz; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta; Herrero-Vanrell, Rocío

    2016-03-01

    To assess the neuroprotective effects of ketorolac administration, in solution or delivered from biodegradable microspheres, on the survival of axotomized retinal ganglion cells (RGCs). Retinas were treated intravitreally with a single injection of tromethamine ketorolac solution and/or with ketorolac-loaded poly(D,L-lactide-co-glycolide) (PLGA) microspheres. Ketorolac treatments were administered either 1 week before optic nerve crush (pre-ONC) or right after the ONC (simultaneous). In all cases, animals were euthanized 7 days after the ONC. As control, nonloaded microspheres or vehicle (balanced salt solution, BSS) were administered in parallel groups. All retinas were dissected as flat mounts; RGCs were immunodetected with brain-specific homeobox/POU domain protein 3A (Brn3a), and their number was automatically quantified. The percentage of Brn3a+RGCs was 36% to 41% in all control groups (ONC with or without BSS or nonloaded microparticles). Ketorolac solution administered pre-ONC resulted in 63% survival of RGCs, while simultaneous administration promoted a 53% survival. Ketorolac-loaded microspheres were not as efficient as ketorolac solution (43% and 42% of RGC survival pre-ONC or simultaneous, respectively). The combination of ketorolac solution and ketorolac-loaded microspheres did not have an additive effect (54% and 55% survival pre-ONC and simultaneous delivery, respectively). Treatment with the nonsteroidal anti-inflammatory drug ketorolac delays RGC death triggered by a traumatic axonal insult. Pretreatment seems to elicit a better output than simultaneous administration of ketorolac solution. This may be taken into account when performing procedures resulting in RGC axonal injury.

  9. Optical properties of retinal tissue and the potential of adaptive optics to visualize retinal ganglion cells in vivo.

    PubMed

    Prasse, Martina; Rauscher, Franziska Georgia; Wiedemann, Peter; Reichenbach, Andreas; Francke, Mike

    2013-08-01

    Many efforts have been made to improve the diagnostic tools used to identify and to estimate the progress of ganglion cell and nerve fibre degeneration in glaucoma. Imaging by optical coherence tomography and measurements of the dimensions of the optic nerve head and the nerve fibre layer in central retinal areas is currently used to estimate the grade of pathological changes. The visualization and quantification of ganglion cells and nerve fibres directly in patients would dramatically improve glaucoma diagnostics. We have investigated the optical properties of cellular structures of retinal tissue in order to establish a means of visualizing and quantifying ganglion cells in the living retina without staining. We have characterized the optical properties of retinal tissue in several species including humans. Nerve fibres, blood vessels, ganglion cells and their cell processes have been visualized at high image resolution by means of the reflection mode of a confocal laser scanning microscope. The potential of adaptive optics in current imaging systems and the possibilities of imaging single ganglion cells non-invasively in patients are discussed.

  10. Can Retinal Ganglion Cell Dipoles Seed Iso-Orientation Domains in the Visual Cortex?

    PubMed Central

    Schottdorf, Manuel; Eglen, Stephen J.; Wolf, Fred; Keil, Wolfgang

    2014-01-01

    It has been argued that the emergence of roughly periodic orientation preference maps (OPMs) in the primary visual cortex (V1) of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs). The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex. PMID:24475081

  11. Correlation in the Discharges of Neighboring Rat Retinal Ganglion Cells During Prenatal Life

    NASA Astrophysics Data System (ADS)

    Maffei, Lamberto; Galli-Resta, Lucia

    1990-04-01

    The spontaneous discharges of neighboring retinal ganglion cells were recorded simultaneously in anesthetized prenatal rats between embryonic days 18 and 21. We report here that in the majority of cases the firings of neighboring retinal ganglion cells are strongly correlated during prenatal life. Correlation in the discharges of neighboring cells during development has long been suggested as a way to consolidate synaptic connections with a target cell onto which they converge, a model first proposed by Hebb. Correlation in the activities of neighboring neurons in the retina could be the basis of developmental processes such as refinement of retinotopic maps in the brain and segregation of the inputs from the two eyes.

  12. Divisive suppression explains high-precision firing and contrast adaptation in retinal ganglion cells.

    PubMed

    Cui, Yuwei; Wang, Yanbin V; Park, Silvia J H; Demb, Jonathan B; Butts, Daniel A

    2016-11-14

    Visual processing depends on specific computations implemented by complex neural circuits. Here, we present a circuit-inspired model of retinal ganglion cell computation, targeted to explain their temporal dynamics and adaptation to contrast. To localize the sources of such processing, we used recordings at the levels of synaptic input and spiking output in the in vitro mouse retina. We found that an ON-Alpha ganglion cell's excitatory synaptic inputs were described by a divisive interaction between excitation and delayed suppression, which explained nonlinear processing that was already present in ganglion cell inputs. Ganglion cell output was further shaped by spike generation mechanisms. The full model accurately predicted spike responses with unprecedented millisecond precision, and accurately described contrast adaptation of the spike train. These results demonstrate how circuit and cell-intrinsic mechanisms interact for ganglion cell function and, more generally, illustrate the power of circuit-inspired modeling of sensory processing.

  13. Ganglion cell distribution and retinal resolution in the Florida manatee, Trichechus manatus latirostris.

    PubMed

    Mass, Alla M; Ketten, Darlene R; Odell, Daniel K; Supin, Alexander Ya

    2012-01-01

    The topographic organization of retinal ganglion cells was examined in the Florida manatee (Trichechus manatus latirostris) to assess ganglion cell size and distribution and to estimate retinal resolution. The ganglion cell layer of the manatee's retina was comprised primarily of large neurons with broad intercellular spaces. Cell sizes varied from 10 to 60 μm in diameter (mean 24.3 μm). The retinal wholemounts from adult animals measured 446-501 mm(2) in area with total ganglion cell counts of 62,000-81,800 (mean 70,200). The cell density changed across the retina, with the maximum in the area below the optic disc and decreasing toward the retinal edges and in the immediate vicinity of the optic disc. The maximum cell density ranged from 235 to 337 cells per millimeter square in the adult retinae. Two wholemounts obtained from juvenile animals were 271 and 282 mm(2) in area with total cell numbers of 70,900 and 68,700, respectively (mean 69,800), that is, nearly equivalent to those of adults, but juvenile retinae consequently had maximum cell densities that were higher than those of adults: 478 and 491 cells per millimeter square. Calculations indicate a retinal resolution of ∼19' (1.6 cycles per degree) in both adult and juvenile retinae. Copyright © 2011 Wiley Periodicals, Inc.

  14. Cyclic AMP and the regeneration of retinal ganglion cell axons.

    PubMed

    Hellström, Mats; Harvey, Alan R

    2014-11-01

    In this paper we present a brief review of studies that have reported therapeutic benefits of elevated cAMP on plasticity and regeneration after injury to the central nervous system (CNS). We also provide new data on the cellular mechanisms by which elevation of cyclic adenosine monophosphate (cAMP) promotes cytokine driven regeneration of adult CNS axons, using the visual system as the experimental model. cAMP is a second messenger for many intracellular signalling pathways. Elevation of cAMP in the eye by intravitreal injection of the cell permeant analogue (8-(4-chlorophenylthio)-adenosine-3',5'-cyclic monophosphate; CPT-cAMP), when added to recombinant ciliary neurotrophic factor (rCNTF), significantly enhances rCNTF-induced regeneration of adult rat retinal ganglion cell (RGC) axons into peripheral nerve (PN) grafted onto transected optic nerve. This effect is mediated to some extent by protein kinase A (PKA) signalling, but CPT-cAMP also acts via PI3K/Akt signalling to reduce suppressor of cytokine signalling protein 3 (SOCS3) activity in RGCs. Another target for cAMP is the exchange protein activated by cAMP (Epac), which can also mediate cAMP-induced axonal growth. Here we describe some novel results and discuss to what extent the pro-regenerative effects of CPT-cAMP on adult RGCs are mediated via Epac as well as via PKA-dependent pathways. We used the established PN-optic nerve graft model and quantified the survival and regenerative growth of adult rat RGCs after intravitreal injection of rCNTF in combination with a selective activator of PKA and/or a specific activator of Epac. Viable RGCs were identified by βIII-tubulin immunohistochemistry and regenerating RGCs retrogradely labelled and quantified after an injection of fluorogold into the distal end of the PN grafts, 4 weeks post-transplantation. The specific agonists of either PKA or Epac were both effective in enhancing the effects of rCNTF on RGC axonal regeneration, but interestingly, injections

  15. Displaced retinal ganglion cells in albino and pigmented rats

    PubMed Central

    Nadal-Nicolás, Francisco M.; Salinas-Navarro, Manuel; Jiménez-López, Manuel; Sobrado-Calvo, Paloma; Villegas-Pérez, María P.; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

    2014-01-01

    We have studied in parallel the population of displaced retinal ganglion cells (dRGCs) and normally placed (orthotopic RGCs, oRGCs) in albino and pigmented rats. Using retrograde tracing from the optic nerve, from both superior colliculi (SC) or from the ipsilateral SC in conjunction with Brn3 and melanopsin immunodetection, we report for the first time their total number and topography as well as the number and distribution of those dRGCs and oRGCs that project ipsi- or contralaterally and/or that express any of the three Brn3 isoforms or melanopsin. The total number of RGCs (oRGCs+dRGCs) is 84,706 ± 1249 in albino and 90,440 ± 2236 in pigmented, out of which 2383 and 2428 are melanopsin positive (m-RGCs), respectively. Regarding dRGCs: i/ albino rats have a significantly lower number of dRGCs than pigmented animals (0.5% of the total number of RGCs vs. 2.5%, respectively), ii/ dRGCs project massively to the contralateral SC, iii/ the percentage of ipsilaterality is higher for dRGCs than for oRGCs, iv/ a higher proportion of ipsilateral dRGCs is observed in albino than pigmented animals, v/ dRGC topography is very specific, they predominate in the equatorial temporal retina, being densest where the oRGCs are densest, vi/ Brn3a detects all dRGCs except half of the ipsilateral ones and those that express melanopsin, vii/ the proportion of dRGCs that express Brn3b or Brn3c is slightly lower than in the oRGC population, viii/ a higher percentage of dRGCs (13% albino, 9% pigmented) than oRGCs (2.6%) express melanopsin, ix/ few m-RGCs (displaced and orthotopic) project to the ipsilateral SC, x/ the topography of m-dRGCs does not resemble the general distribution of dRGCs, xi/ The soma size in m-oRGCs ranges from 10 to 21 μm and in m-dRGCs from 8 to 15 μm, xii/ oRGCs and dRGCs have the same susceptibility to axonal injury and ocular hypertension. Although the role of mammalian dRGCs remains to be determined, our data suggest that they are not misplaced by an

  16. Efficacy of electrical stimulation of retinal ganglion cells with temporal patterns resembling light-evoked spike trains.

    PubMed

    Wong, Raymond C S; Garrett, David J; Grayden, David B; Ibbotson, Michael R; Cloherty, Shaun L

    2014-01-01

    People with degenerative retinal diseases such as retinitis pigmentosa lose most of their photoreceptors but retain a significant proportion (~30%) of their retinal ganglion cells (RGCs). Microelectronic retinal prostheses aim to bypass the lost photoreceptors and restore vision by directly stimulating the surviving RGCs. Here we investigate the extent to which electrical stimulation of RGCs can evoke neural spike trains with statistics resembling those of normal visually-evoked responses. Whole-cell patch clamp recordings were made from individual cat RGCs in vitro. We first recorded the responses of each cell to short sequences of visual stimulation. These responses were converted to trains of electrical stimulation that we then presented to the same cell via an epiretinal stimulating electrode. We then quantified the efficacy of the electrical stimuli and the latency of the evoked spikes. In all cases, spikes were evoked with sub-millisecond latency (0.55 ms, median, ON cells, n = 8; 0.75 ms, median, OFF cells, n = 6) and efficacy ranged from 0.4-1.0 (0.79, median, ON cells; 0.97, median, OFF cells). These data demonstrate that meaningful spike trains, resembling normal responses of RGCs to visual stimulation, can be reliably evoked by epiretinal prostheses.

  17. Changes in ganglion cell physiology during retinal degeneration influence excitability by prosthetic electrodes

    NASA Astrophysics Data System (ADS)

    Cho, Alice; Ratliff, Charles; Sampath, Alapakkam; Weiland, James

    2016-04-01

    Objective. Here we investigate ganglion cell physiology in healthy and degenerating retina to test its influence on threshold to electrical stimulation. Approach. Age-related Macular Degeneration and Retinitis Pigmentosa cause blindness via outer retinal degeneration. Inner retinal pathways that transmit visual information to the central brain remain intact, so direct electrical stimulation from prosthetic devices offers the possibility for visual restoration. Since inner retinal physiology changes during degeneration, we characterize physiological properties and responses to electrical stimulation in retinal ganglion cells (RGCs) of both wild type mice and the rd10 mouse model of retinal degeneration. Main results. Our aggregate results support previous observations that elevated thresholds characterize diseased retinas. However, a physiology-driven classification scheme reveals distinct sub-populations of ganglion cells with thresholds either normal or strongly elevated compared to wild-type. When these populations are combined, only a weakly elevated threshold with large variance is observed. The cells with normal threshold are more depolarized at rest and exhibit periodic oscillations. Significance. During degeneration, physiological changes in RGCs affect the threshold stimulation currents required to evoke action potentials.

  18. An efficient method that reveals both the dendrites and the soma mosaics of retinal ganglion cells.

    PubMed

    Zhan, X J; Troy, J B

    1997-03-01

    A method of using neurobiotin to stain both the dendrites and the soma mosaics of retinal ganglion cells in fresh retinae is described. This method is simple to use and efficient in revealing morphological details for a large number of retinal ganglion cells. It has five advantages over currently available staining methods. (1) It stains all ganglion cells in the whole retina or in a selected retinal area, permitting ganglion cell distributions across the retina to be obtained. (2) It reveals cell dendrites in great detail, especially in regions outside the area centralis. The dendritic field mosaics and, therefore the dendritic field coverage factors, of different ganglion cell types across the whole retina can be obtained easily. (3) It works reliably, efficiently, and does not require the expensive set-up or the pains-taking work needed when staining cells through intracellular injection. (4) It works under both in vivo and in vitro settings, permitting the use of retinae from animals sacrificed for other purposes and the use of postmortem human retinae. (5) The end product of the visualization process is optically dark and electron dense, permitting specimens to be examined under both light and electron microscopes.

  19. Neuroprotective Effect of Tauroursodeoxycholic Acid on N-Methyl-D-Aspartate-Induced Retinal Ganglion Cell Degeneration.

    PubMed

    Gómez-Vicente, Violeta; Lax, Pedro; Fernández-Sánchez, Laura; Rondón, Netxibeth; Esquiva, Gema; Germain, Francisco; de la Villa, Pedro; Cuenca, Nicolás

    2015-01-01

    Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss.

  20. Neuroprotective Effect of Tauroursodeoxycholic Acid on N-Methyl-D-Aspartate-Induced Retinal Ganglion Cell Degeneration

    PubMed Central

    Fernández-Sánchez, Laura; Rondón, Netxibeth; Esquiva, Gema; Germain, Francisco; de la Villa, Pedro; Cuenca, Nicolás

    2015-01-01

    Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss. PMID:26379056

  1. Cross-correlation analysis of the maintained discharge of rabbit retinal ganglion cells.

    PubMed Central

    Arnett, D; Spraker, T E

    1981-01-01

    1. Simultaneous recordings were made from pairs of rabbit retinal ganglion cells. Physiological tests were used to classify the receptive field properties of each cell and the receptive field locations were mapped. 2. The statistical dependence between simultaneously recorded retinal ganglion cells was assessed by cross-correlating the maintained discharge of the simultaneously recorded cells. Cross-correlations from cell pairs in which the constituent cells had non-overlapping receptive field centres were statistically flat, reflecting no statistical dependence. 3. Most cell pairs consisting of transient and sustained concentric cells and having overlapping receptive field centres exhibited a correlated maintained discharge indicative of statistical dependence. The strength of the statistical dependence varied approximately inversely with the degree of overlap between the two cells comprising the cell pair. 4. Cell pairs consisting of two ON-centre cells or two OFF-centre cells and having overlapping receptive field centres possessed incremental cross-correlations which were characterized by a peak centred near zero. Cell pairs consisting of an ON-centre cell with an OFF-centre and having overlapping receptive field centres possessed decremental cross-correlations which were characterized by a valley centred near zero. 5. The results are consistent with the hypothesis that a noise source provides shared input to two or more retinal ganglion cells. Bipolar and photoreceptors are the most likely sources of noise responsible for the statistical dependency between retinal ganglion cells. PMID:7310736

  2. Electrical stimulation of retinal ganglion cells with diamond and the development of an all diamond retinal prosthesis.

    PubMed

    Hadjinicolaou, Alex E; Leung, Ronald T; Garrett, David J; Ganesan, Kumaravelu; Fox, Kate; Nayagam, David A X; Shivdasani, Mohit N; Meffin, Hamish; Ibbotson, Michael R; Prawer, Steven; O'Brien, Brendan J

    2012-08-01

    Electronic retinal implants for the blind are already a market reality. A world wide effort is underway to find the technology that offers the best combination of performance and safety for potential patients. Our approach is to construct an epi-retinally targeted device entirely encapsulated in diamond to maximise longevity and biocompatibility. The stimulating array of our device comprises a monolith of electrically insulating diamond with thousands of hermetic, microscale nitrogen doped ultra-nanocrystalline diamond (N-UNCD) feedthroughs. Here we seek to establish whether the conducting diamond feedthroughs of the array can be used as stimulating electrodes without further modification with a more traditional neural stimulation material. Efficacious stimulation of retinal ganglion cells was established using single N-UNCD microelectrodes in contact with perfused, explanted, rat retina. Evoked rat retinal ganglion cell action potentials were recorded by patch clamp recording from single ganglion cells, adjacent to the N-UNCD stimulating electrode. Separately, excellent electrochemical stability of N-UNCD was established by prolonged pulsing in phosphate buffered saline at increasing charge density up to the measured charge injection limit for the material.

  3. Background Light and the Contrast Gain of Primate P and M Retinal Ganglion Cells

    NASA Astrophysics Data System (ADS)

    Purpura, K.; Kaplan, E.; Shapley, R. M.

    1988-06-01

    Retinal ganglion cells projecting to the monkey lateral geniculate nucleus fall into two classes: those projecting to the magnocellular layers of the nucleus (M cells) have a higher contrast gain to luminance patterns at photopic levels of retinal illumination than those projecting to the parvocellular layers (P cells). We report here that this difference in luminance contrast gain between M and P cells is maintained at low levels of mean retinal illumination. In fact, our results suggest that in the mesopic and scotopic ranges of mean illumination, the M-cell/magnocellular pathway is the predominant conveyor of information about spatial contrast to the visual cortex.

  4. Retinal ganglion cell distribution and spatial resolving power in deep-sea lanternfishes (Myctophidae).

    PubMed

    de Busserolles, Fanny; Marshall, N Justin; Collin, Shaun P

    2014-01-01

    Topographic analyses of retinal ganglion cell density are very useful in providing information about the visual ecology of a species by identifying areas of acute vision within the visual field (i.e. areas of high cell density). In this study, we investigated the neural cell distribution in the ganglion cell layer of a range of lanternfish species belonging to 10 genera. Analyses were performed on wholemounted retinas using stereology. Topographic maps were constructed of the distribution of all neurons and both ganglion and amacrine cell populations in 5 different species from Nissl-stained retinas using cytological criteria. Amacrine cell distribution was also examined immunohistochemically in 2 of the 5 species using anti-parvalbumin antibody. The distributions of both the total neuron and the amacrine cell populations were aligned in all of the species examined, showing a general increase in cell density toward the retinal periphery. However, when the ganglion cell population was topographically isolated from the amacrine cell population, which comprised up to 80% of the total neurons within the ganglion cell layer, a different distribution was revealed. Topographic maps of the true ganglion cell distribution in 18 species of lanternfishes revealed well-defined specializations in different regions of the retina. Different species possessed distinct areas of high ganglion cell density with respect to both peak density and the location and/or shape of the specialized acute zone (i.e. elongated areae ventro-temporales, areae temporales and large areae centrales). The spatial resolving power was calculated to be relatively low (varying from 1.6 to 4.4 cycles per degree), indicating that myctophids may constitute one of the less visually acute groups of deep-sea teleosts. The diversity in retinal specializations and spatial resolving power within the family is assessed in terms of possible ecological functions and evolutionary history. © 2014 S. Karger AG, Basel.

  5. The distribution and significance of aberrant ganglion cells in the facial nerve trunk of the cat.

    PubMed

    Satomi, H; Takahashi, K

    1986-01-01

    The distribution and peripheral connections of aberrant ganglion cells in the facial nerve trunk of the cat were studied by means of Klüver-Barrera staining and retrograde transport of horseradish peroxidase (HRP). By the Klüver-Barrera staining, aberrant ganglion cells were observed in the facial nerve trunk between the geniculate ganglion and the junction of the auricular branch of the vagus with the facial nerve trunk, although the number varied considerably with each animal. These cells were generally medium-sized and of round or oval shape, with densely stained Nissl substance, the features of which were essentially similar to those of the geniculate ganglion. In cases where HRP injections were made into the anterior wall of the auricle, several HRP-labeled cells were found ipsilaterally in the facial nerve trunk in addition to cell labeling of the geniculate ganglion. The present study in the cat demonstrated that at least some of the aberrant ganglion cells scattered in the facial nerve trunk are parental to the axons to the auricle, subserving the cutaneous sensory function.

  6. Classification of retinal ganglion cells in the southern hemisphere lamprey Geotria australis (Cyclostomata).

    PubMed

    Fletcher, Lee Norman; Coimbra, João Paulo; Rodger, Jennifer; Potter, Ian C; Gill, Howard S; Dunlop, Sarah A; Collin, Shaun P

    2014-03-01

    Lampreys are one of two extant representatives of the earliest group of vertebrates, the agnathans or jawless fishes. The single species of the southern hemisphere lamprey family Geotriidae, Geotria australis, possesses the potential for pentachromatic color discrimination opposed to the mono- or dichromacy found in other lampreys. However, little is known of the retinal ganglion cell types that contribute to visual processing in G. australis. A quantitative morphological approach was used to distinguish and describe retinal ganglion cell types in G. australis. The morphology of retinal ganglion cells was revealed by retrograde biocytin labeling from the optic disc. Cells were digitally reconstructed, and somatic area and position and dendritic field size, density, tortuosity, and stratification were subjected to quantitative morphometric analyses. Cluster analysis, in conjunction with similarity profile analysis (SIMPROF), statistically identified five discrete monostratified retinal ganglion cell types, one of which may comprise two subtypes. Two bistratified types were identified separately, including a biplexiform and a bistratified subtype. The use of cluster analysis with SIMPROF provided a robust statistical technique for objectively identifying cell types whose characteristics were similar and significantly different from those of other types and thus provides an objective resolution of the problems posed by "lumpers vs. splitters" when designating cell types. The diversity of retinal ganglion cells suggests that visual information in the lamprey G. australis is processed in parallel streams, as in gnathostomes. These findings, together with the results of previous studies, indicate that the visual system of the lamprey G. australis represents the upper limit of visual complexity in extant agnathans. © 2013 Wiley Periodicals, Inc.

  7. Population activity changes during a trial-to-trial adaptation of bullfrog retinal ganglion cells.

    PubMed

    Ding, Wei; Xiao, Lei; Jing, Wei; Zhang, Pu-Ming; Liang, Pei-Ji

    2014-07-09

    A 'trial-to-trial adaptation' of bullfrog retinal ganglion cells in response to a repetitive light stimulus was investigated in the present study. Using the multielectrode recording technique, we studied the trial-to-trial adaptive properties of ganglion cells and explored the activity of population neurons during this adaptation process. It was found that the ganglion cells adapted with different degrees: their firing rates were decreased in different extents from early-adaptation to late-adaptation stage, and this was accompanied by a decrease in cross-correlation strength. In addition, adaptation behavior was different for ON-response and OFF-response, which implied that the mechanism of the trial-to-trial adaptation might involve bipolar cells and/or their synapses with other neurons and the stronger adaptation in the ganglion cells' OFF-responses might reflect the requirement to avoid possible saturation in the OFF circuit.

  8. Lens injury stimulates adult mouse retinal ganglion cell axon regeneration via both macrophage- and lens-derived factors.

    PubMed

    Lorber, Barbara; Berry, Martin; Logan, Ann

    2005-04-01

    In the present study the effects of lens injury on retinal ganglion cell axon/neurite re-growth were investigated in adult mice. In vivo, lens injury promoted successful regeneration of retinal ganglion cell axons past the optic nerve lesion site, concomitant with the invasion of macrophages into the eye and the presence of activated retinal astrocytes/Muller cells. In vitro, retinal ganglion cells from lens-lesioned mice grew significantly longer neurites than those from intact mice, which correlated with the presence of enhanced numbers of activated retinal astrocytes/Muller cells. Co-culture of retinal ganglion cells from intact mice with macrophage-rich lesioned lens/vitreous body led to increased neurite lengths compared with co-culture with macrophage-free intact lens/vitreous body, pointing to a neurotrophic effect of macrophages. Furthermore, retinal ganglion cells from mice that had no lens injury but had received intravitreal Zymosan injections to stimulate macrophage invasion into the eye grew significantly longer neurites compared with controls, as did retinal ganglion cells from intact mice co-cultured with macrophage-rich vitreous body from Zymosan-treated mice. The intact lens, but not the intact vitreous body, exerted a neurotrophic effect on retinal ganglion cell neurite outgrowth, suggesting that lens-derived neurotrophic factor(s) conspire with those derived from macrophages in lens injury-stimulated axon regeneration. Together, these results show that lens injury promotes retinal ganglion cell axon regeneration/neurite outgrowth in adult mice, an observation with important implications for axon regeneration studies in transgenic mouse models.

  9. Postconditioning with inhaled hydrogen promotes survival of retinal ganglion cells in a rat model of retinal ischemia/reperfusion injury.

    PubMed

    Wang, Ruobing; Wu, Jiangchun; Chen, Zeli; Xia, Fangzhou; Sun, Qinglei; Liu, Lin

    2016-02-01

    Retinal ischemia/reperfusion (I/R) injury plays a crucial role in the pathophysiology of various ocular diseases. Intraperitoneal injection or ocular instillation with hydrogen (H2)-rich saline was recently shown to be neuroprotective in the retina due to its anti-oxidative and anti-inflammatory effects. Our study aims to explore whether postconditioning with inhaled H2 can protect retinal ganglion cells (RGCs) in a rat model of retinal I/R injury. Retinal I/R injury was performed on the right eyes of rats and was followed by inhalation of 67% H2 mixed with 33% oxygen immediately after ischemia for 1h daily for one week. RGC density was counted using haematoxylin and eosin (HE) staining and retrograde labeling with cholera toxin beta (CTB). Visual function was assessed using flash visual evoked potentials (FVEP) and pupillary light reflex (PLR). Potential biomarkers of retinal oxidative stress and inflammatory responses were measured, including the expression of 4-Hydroxynonenalv (4-HNE), interleukin-1 beta (IL1-β) and tumor necrosis factor alpha (TNF-α). HE and CTB tracing showed that the survival rate of RGCs in the H2-treated group was significantly higher than the rate in the I/R group. Rats with H2 inhalation showed better visual function in assessments of FVEP and PLR. Moreover, H2 treatment significantly decreased the number of 4-HNE-stained cells in the ganglion cell layer and inhibited the retinal overexpression of IL1-β and TNF-α that was induced by retinal I/R injury. Our results demonstrate that postconditioning with inhaled high-dose H2 appears to confer neuroprotection against retinal I/R injury via anti-oxidative, anti-inflammatory and anti-apoptosis pathways.

  10. Msx2 alters the timing of retinal ganglion cells fate commitment and differentiation

    SciTech Connect

    Jiang, Shao-Yun; Wang, Jian-Tao

    2010-05-14

    Timing of cell fate commitment determines distinct retinal cell types, which is believed to be controlled by a tightly coordinated regulatory program of proliferation, cell cycle exit and differentiation. Although homeobox protein Msx2 could induce apoptosis of optic vesicle, it is unclear whether Msx2 regulates differentiation and cell fate commitment of retinal progenitor cells (RPCs) to retinal ganglion cells (RGCs). In this study, we show that overexpression of Msx2 transiently suppressed the expression of Cyclin D1 and blocked cell proliferation. Meanwhile, overexpression of Msx2 delayed the expression of RGC-specific differentiation markers (Math5 and Brn3b), which showed that Msx2 could affect the timing of RGCs fate commitment and differentiation by delaying the timing of cell cycle exit of retinal progenitors. These results indicate Msx2 possesses dual regulatory functions in controlling cell cycle progression of retinal RPCs and timing of RGCs differentiation.

  11. KR-31378, a potassium-channel opener, induces the protection of retinal ganglion cells in rat retinal ischemic models.

    PubMed

    Choi, Anho; Choi, Jun-Sub; Yoon, Yone-Jung; Kim, Kyung-A; Joo, Choun-Ki

    2009-04-01

    KR-31378 is a newly developed K(ATP)-channel opener. To investigate the ability of KR-31378 to protect retinal ganglion cells (RGC), experiments were conducted using two retinal ischemia models. Retinal ischemia was induced by transient high intraocular pressure (IOP) for acute ischemia and by three episcleral vein occlusion for chronic retinal ischemia. KR-31378 was injected intraperitoneally and administered orally in the acute and chronic ischemia models, respectively. Under the condition of chronic ischemia, RGC density in the KR-31378-treated group was statistically higher than that in the non-treated group, and IOP was reduced. In the acute retinal ischemia model, 90% of RGC were degenerated after one week in non-treated retina, but, RGC in KR-31378-treated retina were protected from ischemic damage in a dose-dependent manner and showed inhibited glial fibrillary acidic protein (GFAP) expression. Furthermore, the KR-31378 protective effect was inhibited by glibenclamide treatment in acute ischemia. These findings indicate that systemic KR-31378 treatment may protect against ischemic injury-induced ganglion cell loss in glaucoma.

  12. Plasticity in adult cat visual cortex (area 17) following circumscribed monocular lesions of all retinal layers

    PubMed Central

    Calford, M B; Wang, C; Taglianetti, V; Waleszczyk, W J; Burke, W; Dreher, B

    2000-01-01

    In eight adult cats intense, sharply circumscribed, monocular laser lesions were used to remove all cellular layers of the retina. The extents of the retinal lesions were subsequently confirmed with counts of α-ganglion cells in retinal whole mounts; in some cases these revealed radial segmental degeneration of ganglion cells distal to the lesion.Two to 24 weeks later, area 17 (striate cortex; V1) was studied electrophysiologically in a standard anaesthetized, paralysed (artificially respired) preparation. Recording single- or multineurone activity revealed extensive topographical reorganization within the lesion projection zone (LPZ).Thus, with stimulation of the lesioned eye, about 75 % of single neurones in the LPZ had ‘ectopic’ visual discharge fields which were displaced to normal retina in the immediate vicinity of the lesion.The sizes of the ectopic discharge fields were not significantly different from the sizes of the normal discharge fields. Furthermore, binocular cells recorded from the LPZ, when stimulated via their ectopic receptive fields, exhibited orientation tuning and preferred stimulus velocities which were indistinguishable from those found when the cells were stimulated via the normal eye.However, the responses to stimuli presented via ectopic discharge fields were generally weaker (lower peak discharge rates) than those to presentations via normal discharge fields, and were characterized by a lower-than-normal upper velocity limit.Overall, the properties of the ectopic receptive fields indicate that cortical mechanisms rather than a retinal ‘periphery’ effect underlie the topographic reorganization of area 17 following monocular retinal lesions. PMID:10767137

  13. Ocular anatomy, ganglion cell distribution and retinal resolution of a killer whale (Orcinus orca).

    PubMed

    Mass, Alla M; Supin, Alexander Y; Abramov, Andrey V; Mukhametov, Lev M; Rozanova, Elena I

    2013-01-01

    Retinal topography, cell density and sizes of ganglion cells in the killer whale (Orcinus orca) were analyzed in retinal whole mounts stained with cresyl violet. A distinctive feature of the killer whale's retina is the large size of ganglion cells and low cell density compared to terrestrial mammals. The ganglion cell diameter ranged from 8 to 100 µm, with the majority of cells within a range of 20-40 µm. The topographic distribution of ganglion cells displayed two spots of high cell density located in the temporal and nasal quadrants, 20 mm from the optic disk. The high-density areas were connected by a horizontal belt-like area passing below the optic disk of the retina. Peak cell densities in these areas were evaluated. Mean peak cell densities were 334 and 288 cells/mm(2) in the temporal and nasal high-density areas, respectively. With a posterior nodal distance of 19.5 mm, these high-density data predict a retinal resolution of 9.6' (3.1 cycles/deg.) and 12.6' (2.4 cycles/deg.) in the temporal and nasal areas, respectively, in water. Copyright © 2012 S. Karger AG, Basel.

  14. Is the capacity for optic nerve regeneration related to continued retinal ganglion cell production in the frog?

    PubMed

    Taylor, J S; Jack, J L; Easter, S S

    1989-01-01

    In the central nervous system of fish and frogs, some, but not all, axons can regenerate. Retinal ganglion cells are among those that can. The retinae of fish and frogs produce new retinal neurons, including ganglion cells, for months or years after hatching. We have evaluated the hypothesis that retinal axonal regeneration is obligatorily linked to continued production of new ganglion cells. We used bromodeoxyuridine immunocytochemistry to assess retinal neurogenesis in juvenile, yearling, and 10 year old Xenopus laevis. Retinal ganglion cell genesis was vigorous in the marginal retina of the juveniles, but in the yearlings and the 10 year olds, no new ganglion cells were produced there. Cellular proliferation in the central retina was evident at all three ages, but none of the cells produced centrally were in the ganglion cell layer. Regeneration was examined in vivo by cutting one optic nerve and then, weeks later, injecting the eye with tritiated proline. Autoradiographs of brain sections showed that the optic nerves of all three ages regenerated. Regeneration in vitro was assessed using retinal explants from frogs of all three ages. In all cases, the cultures produced neurites, with some age-specific differences in the patterns of outgrowth. We conclude that retinal axonal regeneration is not linked obligatorily to maintained neurogenesis.

  15. Internalization and synaptogenic effect of GH in retinal ganglion cells (RGCs).

    PubMed

    Fleming, Thomas; Martínez-Moreno, Carlos G; Mora, Janeth; Aizouki, Miray; Luna, Maricela; Arámburo, Carlos; Harvey, Steve

    2016-08-01

    In the chicken embryo, GH gene expression occurs in the neural retina and retinal GH promotes cell survival and induces axonal growth of retinal ganglion cells. Neuroretinal GH is therefore of functional importance before the appearance of somatotrophs and the onset of pituitary GH secretion to the peripheral plasma (at ED15-17). Endocrine actions of pituitary GH in the development and function of the chicken embryo eye are, however, unknown. This possibility has therefore been investigated in ED15 embryos and using the quail neuroretinal derived cell line (QNR/D). During this research, we studied for the first time, the coexistence of exogenous (endocrine) and local GH (autocrine/paracrine) in retinal ganglion cells (RGCs). In ovo systemic injections of Cy3-labeled GH demonstrated that GH in the embryo bloodstream was translocated into the neural retina and internalized into RGC's. Pituitary GH may therefore be functionally involved in retinal development during late embryogenesis. Cy3-labelled GH was similarly internalized into QNR/D cells after its addition into incubation media. The uptake of exogenous GH was by a receptor-mediated mechanism and maximal after 30-60min. The exogenous (endocrine) GH induced STAT5 phosphorylation and increased growth associated protein 43 (GAP43) and SNAP-25 immunoreactivity. Ex ovo intravitreal injections of Cy3-GH in ED12 embryos resulted in GH internalization and STAT5 activation. Interestingly, the CY3-labeled GH accumulated in perinuclear regions of the QNR/D cells, but was not found in the cytoplasm of neurite outgrowths, in which endogenous retinal GH is located. This suggests that exogenous (endocrine) and local (autocrine/paracrine) GH are both involved in retinal function in late embryogenesis but they co-exist in separate intracellular compartments within retinal ganglion cells.

  16. Effect of Stimulus Waveform of Biphasic Current Pulse on Retinal Ganglion Cell Responses in Retinal Degeneration (rd1) mice

    PubMed Central

    Ahn, Kun No; Ahn, Jeong Yeol; Kim, Jae-hyung; Cho, Kyoungrok; Koo, Kyo-in; Senok, Solomon S.

    2015-01-01

    A retinal prosthesis is being developed for the restoration of vision in patients with retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Determining optimal electrical stimulation parameters for the prosthesis is one of the most important elements for the development of a viable retinal prosthesis. Here, we investigated the effects of different charge-balanced biphasic pulses with regard to their effectiveness in evoking retinal ganglion cell (RGC) responses. Retinal degeneration (rd1) mice were used (n=17). From the ex-vivo retinal preparation, retinal patches were placed ganglion cell layer down onto an 8×8 multielectrode array (MEA) and RGC responses were recorded while applying electrical stimuli. For asymmetric pulses, 1st phase of the pulse is the same with symmetric pulse but the amplitude of 2nd phase of the pulse is less than 10 µA and charge balanced condition is satisfied by lengthening the duration of the pulse. For intensities (or duration) modulation, duration (or amplitude) of the pulse was fixed to 500 µs (30 µA), changing the intensities (or duration) from 2 to 60 µA (60 to 1000 µs). RGCs were classified as response-positive when PSTH showed multiple (3~4) peaks within 400 ms post stimulus and the number of spikes was at least 30% more than that for the immediate pre-stimulus 400 ms period. RGC responses were well modulated both with anodic and cathodic phase-1st biphasic pulses. Cathodic phase-1st pulses produced significantly better modulation of RGC activity than anodic phase-1st pulses regardless of symmetry of the pulse. PMID:25729279

  17. Use of an Adult Rat Retinal Explant Model for Screening of Potential Retinal Ganglion Cell Neuroprotective Therapies

    PubMed Central

    Bull, Natalie D.; Johnson, Thomas V.; Welsapar, Guncha; DeKorver, Nicholas W.; Tomarev, Stanislav I.

    2011-01-01

    Purpose. To validate an established adult organotypic retinal explant culture system for use as an efficient medium-throughput screening tool to investigate novel retinal ganglion cell (RGC) neuroprotective therapies. Methods. Optimal culture conditions for detecting RGC neuroprotection in rat retinal explants were identified. Retinal explants were treated with various recognized, or purported, neuroprotective agents and cultured for either 4 or 7 days ex vivo. The number of cells surviving in the RGC layer (RGCL) was quantified using histologic and immunohistochemical techniques, and statistical analyses were applied to detect neuroprotective effects. Results. The ability to replicate previously reported in vivo RGC neuroprotection in retinal explants was verified by demonstrating that caspase inhibition, brain-derived neurotrophic factor treatment, and stem cell transplantation all reduced RGCL cell loss in this model. Further screening of potential neuroprotective pharmacologic agents demonstrated that betaxolol, losartan, tafluprost, and simvastatin all alleviated RGCL cell loss in retinal explants, supporting previous reports. However, treatment with brimonidine did not protect RGCL neurons from death in retinal explant cultures. Explants cultured for 4 days ex vivo proved most sensitive for detecting neuroprotection. Conclusions. The current adult rat retinal explant culture model offers advantages over other models for screening potential neuroprotective drugs, including maintenance of neurons in situ, control of environmental conditions, and dissociation from other factors such as intraocular pressure. Verification that neuroprotection by previously identified RGC-protective therapies could be replicated in adult retinal explant cultures suggests that this model could be used for efficient medium-throughput screening of novel neuroprotective therapies for retinal neurodegenerative disease. PMID:21345987

  18. Nitric oxide differentially modulates ON and OFF responses of retinal ganglion cells.

    PubMed

    Wang, Guo-Yong; Liets, Lauren C; Chalupa, Leo M

    2003-08-01

    Several lines of evidence suggest that nitric oxide (NO) can regulate diverse retinal functions, but whether this gas is capable of modulating the visual responses of retinal output neurons has not been established. In the present study the effects of NO on rod-driven responses of retinal ganglion cells were tested by making whole cell patch-clamp recordings from morphologically identified ganglion cells in the isolated ferret retina. Bath application of L-arginine, the substrate of nitric oxide synthase, and S-nitroso-N-acetylpenicillamine, the NO donor, was found to differentially affect on and off discharge patterns. The introduction of these drugs significantly decreased visual responses of retinal ganglion cells, but the effects were more pronounced on off than on on discharges. The peak discharge rates of on responses were usually reduced by about 40%, but not completely blocked. In contrast, off responses were completely blocked in most cells. These differential effects were observed in on-off cells as well as in cells that yielded just on or off discharges. The off responses that were blocked by NO were also blocked by DL-2-amino-phosphonobutyric acid (APB) and strychnine, suggesting the involvement of the APB-sensitive rod pathway.

  19. Autophagy promotes survival of retinal ganglion cells after optic nerve axotomy in mice

    PubMed Central

    Rodríguez-Muela, N; Germain, F; Mariño, G; Fitze, P S; Boya, P

    2012-01-01

    Autophagy is an essential recycling pathway implicated in neurodegeneration either as a pro-survival or a pro-death mechanism. Its role after axonal injury is still uncertain. Axotomy of the optic nerve is a classical model of neurodegeneration. It induces retinal ganglion cell death, a process also occurring in glaucoma and other optic neuropathies. We analyzed autophagy induction and cell survival following optic nerve transection (ONT) in mice. Our results demonstrate activation of autophagy shortly after axotomy with autophagosome formation, upregulation of the autophagy regulator Atg5 and apoptotic death of 50% of the retinal ganglion cells (RGCs) after 5 days. Genetic downregulation of autophagy using knockout mice for Atg4B (another regulator of autophagy) or with specific deletion of Atg5 in retinal ganglion cells, using the Atg5flox/flox mice reduces cell survival after ONT, whereas pharmacological induction of autophagy in vivo increases the number of surviving cells. In conclusion, our data support that autophagy has a cytoprotective role in RGCs after traumatic injury and may provide a new therapeutic strategy to ameliorate retinal diseases. PMID:21701497

  20. Neuroprotective Effect of Lutein on NMDA-Induced Retinal Ganglion Cell Injury in Rat Retina.

    PubMed

    Zhang, Chanjuan; Wang, Zhen; Zhao, Jiayi; Li, Qin; Huang, Cuiqin; Zhu, Lihong; Lu, Daxiang

    2016-05-01

    Lutein injection is a possible therapeutic approach for retinal diseases, but the molecular mechanism of its neuroprotective effect remains to be elucidated. The aim of this study was to investigate its protective effects in retinal ganglion cells (RGCs) against N-methyl-D-aspartate (NMDA)-induced retinal damage in vivo. Retinal damage was induced by intravitreal NMDA injection in rats. Each animal was given five daily intraperitoneal injections of Lutein or vehicle along with intravitreal NMDA injections. Electroretinograms were recorded. The number of viable RGCs was quantified using the retinal whole-mount method by immunofluorescence. Proteins were measured by Western blot assays. Lutein reduced the retinal damage and improved the response to light, as shown by an animal behavior assay (the black-and-white box method) in rats. Furthermore, Lutein treatment prevented the NMDA-induced reduction in phNR wave amplitude. Lutein increased RGC number after NMDA-induced retina damage. Most importantly, Bax, cytochrome c, p-p38 MAPK, and p-c-Jun were all upregulated in rats injected with NMDA, but these expression patterns were reversed by continuous Lutein uptake. Bcl-2, p-GSK-3β, and p-Akt in the Lutein-treated eyes were increased compared with the NMDA group. Lutein has neuroprotective effects against retinal damage, its protective effects may be partly mediated by its anti-excitability neurotoxicity, through MAPKs and PI3K/Akt signaling, suggesting a potential approach for suppressing retinal neural damage.

  1. Effects of low level laser treatment on the survival of axotomized retinal ganglion cells in adult Hamsters

    PubMed Central

    So, Kwok-Fai; Leung, Mason Chin Pang; Cui, Qi

    2014-01-01

    Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate. It is known that optic nerve transection close to the eye in rodents leads to a loss of about half of retinal ganglion cells in 1 week and about 90% in 2 weeks. Using low level laser treatment in the present study, we demonstrated that treatment with helium-neon (660 nm) laser with 15 mW power could delay retinal ganglion cell death after optic nerve axotomy in adult hamsters. The effect was most apparent in the first week with a short period of treatment time (5 minutes) in which 65–66% of retinal ganglion cells survived the optic nerve axotomy whereas 45–47% of retinal ganglion cells did so in optic nerve axotomy controls. We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy. These findings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal ganglion cells. PMID:25558230

  2. Retinal ganglion cell projections to the hamster suprachiasmatic nucleus, intergeniculate leaflet, and visual midbrain: bifurcation and melanopsin immunoreactivity

    NASA Technical Reports Server (NTRS)

    Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio

    2003-01-01

    The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.

  3. Retinal ganglion cell projections to the hamster suprachiasmatic nucleus, intergeniculate leaflet, and visual midbrain: bifurcation and melanopsin immunoreactivity

    NASA Technical Reports Server (NTRS)

    Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio

    2003-01-01

    The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.

  4. Imaging individual neurons in the retinal ganglion cell layer of the living eye

    PubMed Central

    Rossi, Ethan A.; Granger, Charles E.; Yang, Qiang; Saito, Kenichi; Schwarz, Christina; Walters, Sarah; Nozato, Koji; Zhang, Jie; Kawakami, Tomoaki; Fischer, William; Latchney, Lisa R.; Hunter, Jennifer J.; Chung, Mina M.; Williams, David R.

    2017-01-01

    Although imaging of the living retina with adaptive optics scanning light ophthalmoscopy (AOSLO) provides microscopic access to individual cells, such as photoreceptors, retinal pigment epithelial cells, and blood cells in the retinal vasculature, other important cell classes, such as retinal ganglion cells, have proven much more challenging to image. The near transparency of inner retinal cells is advantageous for vision, as light must pass through them to reach the photoreceptors, but it has prevented them from being directly imaged in vivo. Here we show that the individual somas of neurons within the retinal ganglion cell (RGC) layer can be imaged with a modification of confocal AOSLO, in both monkeys and humans. Human images of RGC layer neurons did not match the quality of monkey images for several reasons, including safety concerns that limited the light levels permissible for human imaging. We also show that the same technique applied to the photoreceptor layer can resolve ambiguity about cone survival in age-related macular degeneration. The capability to noninvasively image RGC layer neurons in the living eye may one day allow for a better understanding of diseases, such as glaucoma, and accelerate the development of therapeutic strategies that aim to protect these cells. This method may also prove useful for imaging other structures, such as neurons in the brain. PMID:28049835

  5. The Effect of Cochlear-Implant-Mediated Electrical Stimulation on Spiral Ganglion Cells in Congenitally Deaf White Cats

    PubMed Central

    Chen, Iris; Limb, Charles J.

    2010-01-01

    It has long been observed that loss of auditory receptor cells is associated with the progressive degeneration of spiral ganglion cells. Chronic electrical stimulation via cochlear implantation has been used in an attempt to slow the rate of degeneration in cats neonatally deafened by ototoxic agents but with mixed results. The present study examined this issue using white cats with a history of hereditary deafness as an alternative animal model. Nineteen cats provided new data for this study: four normal-hearing cats, seven congenitally deaf white cats, and eight congenitally deaf white cats with unilateral cochlear implants. Data from additional cats were collected from the literature. Electrical stimulation began at 3 to 4 or 6 to 7 months after birth, and cats received stimulation for approximately 7 h a day, 5 days a week for 12 weeks. Quantitative analysis of spiral ganglion cell counts, cell density, and cell body size showed no marked improvement between cochlear-implanted and congenitally deaf subjects. Average ganglion cell size from cochlear-implanted and congenitally deaf cats was statistically similar and smaller than that of normal-hearing cats. Cell density from cats with cochlear implants tended to decrease within the upper basal and middle cochlear turns in comparison to congenitally deaf cats but remained at congenitally deaf levels within the lower basal and apical cochlear turns. These results provide no evidence that chronic electrical stimulation enhances spiral ganglion cell survival, cell density, or cell size compared to that of unstimulated congenitally deaf cats. Regardless of ganglion neuron status, there is unambiguous restoration of auditory nerve synapses in the cochlear nucleus of these cats implanted at the earlier age. PMID:20821032

  6. Visual Field Defects and Retinal Ganglion Cell Losses in Human Glaucoma Patients

    PubMed Central

    Harwerth, Ronald S.; Quigley, Harry A.

    2007-01-01

    Objective The depth of visual field defects are correlated with retinal ganglion cell densities in experimental glaucoma. This study was to determine whether a similar structure-function relationship holds for human glaucoma. Methods The study was based on retinal ganglion cell densities and visual thresholds of patients with documented glaucoma (Kerrigan-Baumrind, et al.) The data were analyzed by a model that predicted ganglion cell densities from standard clinical perimetry, which were then compared to histologic cell counts. Results The model, without free parameters, produced accurate and relatively precise quantification of ganglion cell densities associated with visual field defects. For 437 sets of data, the unity correlation for predicted vs. measured cell densities had a coefficient of determination of 0.39. The mean absolute deviation of the predicted vs. measured values was 2.59 dB, the mean and SD of the distribution of residual errors of prediction was -0.26 ± 3.22 dB. Conclusions Visual field defects by standard clinical perimetry are proportional to neural losses caused by glaucoma. Clinical Relevance The evidence for quantitative structure-function relationships provides a scientific basis of interpreting glaucomatous neuropathy from visual thresholds and supports the application of standard perimetry to establish the stage of the disease. PMID:16769839

  7. Electrical Stimulation of Mammalian Retinal Ganglion Cells Using Dense Arrays of Small-Diameter Electrodes

    NASA Astrophysics Data System (ADS)

    Sekirnjak, Chris; Hottowy, Pawel; Sher, Alexander; Dabrowski, Wladyslaw; Litke, Alan M.; Chichilnisky, E. J.

    Current epiretinal implants contain a small number of electrodes with diameters of a few hundred microns. Smaller electrodes are desirable to increase the spatial resolution of artificial sight. To lay the foundation for the next generation of retinal prostheses, we assessed the stimulation efficacy of micro-fabricated arrays of 61 platinum disk electrodes with diameters 8-12 μm, spaced 60 μm apart. Isolated pieces of rat, guinea pig, and monkey retina were placed on the multi-electrode array ganglion cell side down and stimulated through individual electrodes with biphasic, charge-balanced current pulses. Spike responses from retinal ganglion cells were recorded either from the same or a neighboring electrode. Most pulses evoked only 1-2 spikes with short latencies (0.3-10 ms), and rarely was more than one recorded ganglion cell stimulated. Threshold charge densities for eliciting spikes in ganglion cells were typically below 0.15 mC/cm2 for pulse durations between 50 and 200 μs, corresponding to charge thresholds of ˜ 100 pC. Stimulation remained effective after several hours and at frequencies up to 100 Hz. Application of cadmium chloride did not abolish evoked spikes, implying direct activation. Thus, electrical stimulation of mammalian retina with small-diameter electrodes is achievable, providing high temporal and spatial precision with low charge densities.

  8. Moniliform Deformation of Retinal Ganglion Cells by Formaldehyde-Based Fixatives

    PubMed Central

    Stradleigh, Tyler W.; Greenberg, Kenneth P.; Partida, Gloria J.; Pham, Aaron; Ishida, Andrew T.

    2014-01-01

    Protocols for characterizing cellular phenotypes commonly use chemical fixatives to preserve anatomical features, mechanically stabilize tissue, and stop physiological responses. Formaldehyde, diluted in either phosphate-buffered saline or phosphate buffer, has been widely used in studies of neurons, especially in conjunction with dyes and antibodies. However, previous studies have reported that these fixatives induce the formation of bead-like varicosities in the dendrites and axons of brain and spinal cord neurons. We report here that these formaldehyde formulations can induce bead formation in the dendrites and axons of adult rat and rabbit retinal ganglion cells, and that retinal ganglion cells differ from hippocampal, cortical, cerebellar, and spinal cord neurons in that bead formation is not blocked by glutamate receptor antagonists, a voltage-gated Na+ channel toxin, extracellular Ca2+ ion exclusion, or temperature shifts. Moreover, we describe a modification of formaldehyde-based fixatives that prevents bead formation in retinal ganglion cells visualized by green fluorescent protein expression and by immunohistochemistry. PMID:25283775

  9. Ganglion cells density and retinal resolution in the sea otter, Enhydra lutris.

    PubMed

    Mass, A M; Supin, A Y

    2000-03-01

    The topographic distribution, density, and size of ganglion cells were studied in retinal wholemounts of the sea otter, Enhydra lutris. The cell distribution showed a well defined horizontal streak of higher cell density, and within this streak, a narrow area of the highest cell density. The peak cell density in this area ranged from 4050 to 4400 cells/mm(2), with a mean of 4225 cells/mm(2). The ganglion cell size ranged from 7 microm to 47 microm but the majority of cells were 7 to 30 microm. Cell size distribution revealed three size groups: 7-16, 17-28, and 29-47 microm. The highest-density area contained mainly small (7-16 microm) cells. The cell-density data predict a retinal resolution around 7' in water. Retinal organization in the sea otter exhibits more properties common with terrestrial rather than aquatic mammals, both in terms of ganglion cell characteristics and in terms of their topographic distribution.

  10. Functional segregation of retinal ganglion cell projections to the optic tectum of rainbow trout

    PubMed Central

    Wachowiak, Matt

    2015-01-01

    The interpretation of visual information relies on precise maps of retinal representation in the brain coupled with local circuitry that encodes specific features of the visual scenery. In nonmammalian vertebrates, the main target of ganglion cell projections is the optic tectum. Although the topography of retinotectal projections has been documented for several species, the spatiotemporal patterns of activity and how these depend on background adaptation have not been explored. In this study, we used a combination of electrical and optical recordings to reveal a retinotectal map of ganglion cell projections to the optic tectum of rainbow trout and characterized the spatial and chromatic distribution of ganglion cell fibers coding for increments (ON) and decrements (OFF) of light. Recordings of optic nerve activity under various adapting light backgrounds, which isolated the input of different cone mechanisms, yielded dynamic patterns of ON and OFF input characterized by segregation of these two fiber types. Chromatic adaptation decreased the sensitivity and response latency of affected cone mechanisms, revealing their variable contributions to the ON and OFF responses. Our experiments further demonstrated restricted input from a UV cone mechanism to the anterolateral optic tectum, in accordance with the limited presence of UV cones in the dorsotemporal retina of juvenile rainbow trout. Together, our findings show that retinal inputs to the optic tectum of this species are not homogeneous, exhibit highly dynamic activity patterns, and are likely determined by a combination of biased projections and specific retinal cell distributions and their activity states. PMID:26334009

  11. Moniliform deformation of retinal ganglion cells by formaldehyde-based fixatives.

    PubMed

    Stradleigh, Tyler W; Greenberg, Kenneth P; Partida, Gloria J; Pham, Aaron; Ishida, Andrew T

    2015-03-01

    Protocols for characterizing cellular phenotypes commonly use chemical fixatives to preserve anatomical features, mechanically stabilize tissue, and stop physiological responses. Formaldehyde, diluted in either phosphate-buffered saline or phosphate buffer, has been widely used in studies of neurons, especially in conjunction with dyes and antibodies. However, previous studies have found that these fixatives induce the formation of bead-like varicosities in the dendrites and axons of brain and spinal cord neurons. We report here that these formaldehyde formulations can induce bead formation in the dendrites and axons of adult rat and rabbit retinal ganglion cells, and that retinal ganglion cells differ from hippocampal, cortical, cerebellar, and spinal cord neurons in that bead formation is not blocked by glutamate receptor antagonists, a voltage-gated Na(+) channel toxin, extracellular Ca(2+) ion exclusion, or temperature shifts. Moreover, we describe a modification of formaldehyde-based fixatives that prevents bead formation in retinal ganglion cells visualized by green fluorescent protein expression and by immunohistochemistry. © 2014 Wiley Periodicals, Inc.

  12. Allogeneic Transplantation of Müller-Derived Retinal Ganglion Cells Improves Retinal Function in a Feline Model of Ganglion Cell Depletion.

    PubMed

    Becker, Silke; Eastlake, Karen; Jayaram, Hari; Jones, Megan F; Brown, Robert A; McLellan, Gillian J; Charteris, David G; Khaw, Peng T; Limb, G Astrid

    2016-02-01

    Human Müller glia with stem cell characteristics (hMGSCs) have been shown to improve retinal function upon transplantation into rat models of retinal ganglion cell (RGC) depletion. However, their translational potential may depend upon successful engraftment and improvement of retinal function in experimental models with anatomical and functional features resembling those of the human eye. We investigated the effect of allogeneic transplantation of feline Müller glia with the ability to differentiate into cells expressing RGC markers, following ablation of RGCs by N-methyl-d-aspartate (NMDA). Unlike previous observations in the rat, transplantation of hMGSC-derived RGCs into the feline vitreous formed aggregates and elicited a severe inflammatory response without improving visual function. In contrast, allogeneic transplantation of feline MGSC (fMGSC)-derived RGCs into the vitrectomized eye improved the scotopic threshold response (STR) of the electroretinogram (ERG). Despite causing functional improvement, the cells did not attach onto the retina and formed aggregates on peripheral vitreous remnants, suggesting that vitreous may constitute a barrier for cell attachment onto the retina. This was confirmed by observations that cellular scaffolds of compressed collagen and enriched preparations of fMGSC-derived RGCs facilitated cell attachment. Although cells did not migrate into the RGC layer or the optic nerve, they significantly improved the STR and the photopic negative response of the ERG, indicative of increased RGC function. These results suggest that MGSCs have a neuroprotective ability that promotes partial recovery of impaired RGC function and indicate that cell attachment onto the retina may be necessary for transplanted cells to confer neuroprotection to the retina. Significance: Müller glia with stem cell characteristics are present in the adult human retina, but they do not have regenerative ability. These cells, however, have potential for

  13. Allogeneic Transplantation of Müller-Derived Retinal Ganglion Cells Improves Retinal Function in a Feline Model of Ganglion Cell Depletion

    PubMed Central

    Becker, Silke; Eastlake, Karen; Jayaram, Hari; Jones, Megan F.; Brown, Robert A.; McLellan, Gillian J.; Charteris, David G.; Khaw, Peng T.

    2016-01-01

    Human Müller glia with stem cell characteristics (hMGSCs) have been shown to improve retinal function upon transplantation into rat models of retinal ganglion cell (RGC) depletion. However, their translational potential may depend upon successful engraftment and improvement of retinal function in experimental models with anatomical and functional features resembling those of the human eye. We investigated the effect of allogeneic transplantation of feline Müller glia with the ability to differentiate into cells expressing RGC markers, following ablation of RGCs by N-methyl-d-aspartate (NMDA). Unlike previous observations in the rat, transplantation of hMGSC-derived RGCs into the feline vitreous formed aggregates and elicited a severe inflammatory response without improving visual function. In contrast, allogeneic transplantation of feline MGSC (fMGSC)-derived RGCs into the vitrectomized eye improved the scotopic threshold response (STR) of the electroretinogram (ERG). Despite causing functional improvement, the cells did not attach onto the retina and formed aggregates on peripheral vitreous remnants, suggesting that vitreous may constitute a barrier for cell attachment onto the retina. This was confirmed by observations that cellular scaffolds of compressed collagen and enriched preparations of fMGSC-derived RGCs facilitated cell attachment. Although cells did not migrate into the RGC layer or the optic nerve, they significantly improved the STR and the photopic negative response of the ERG, indicative of increased RGC function. These results suggest that MGSCs have a neuroprotective ability that promotes partial recovery of impaired RGC function and indicate that cell attachment onto the retina may be necessary for transplanted cells to confer neuroprotection to the retina. Significance Müller glia with stem cell characteristics are present in the adult human retina, but they do not have regenerative ability. These cells, however, have potential for

  14. Degeneration stage-specific response pattern of retinal ganglion cell spikes in rd10 mouse retina.

    PubMed

    Park, D J; Senok, S S; Goo, Y S

    2015-01-01

    It is known that with retinal degeneration there is rewiring of retinal networks. Consequently, electrical stimulation of the degenerating retina produces responses that differ according to the stage of retinal degeneration. We sought to delineate a degeneration stage-specific parameter for the response pattern of retinal ganglion cell (RGC) spikes as a strategy for stage-specific electrical stimulation for perceptual efficiency of prosthetic vision devices. Electrically-evoked RGC spikes were recorded at different degeneration stages in the rd10 mouse model for human retinitis pigmentosa (RP). Retinal explants mounted on an 8×8 multi-electrode array were stimulated by applying 1 Hz cathodic-phase first biphasic current pulses. RGC firing rate during the first 100 ms post-stimulus was compared to that during the 100-1000 ms period and a response ratio of 100 ms (RR100 ms) was calculated through the different postnatal weeks. Our results show that during post-stimulus 100-1000 ms, the degree of correlation between pulse amplitude and evoked RGC spikes drastically decreases at PNW 4.5. This pattern was closely matched by the RR100 ms curve at this stage. We conclude that the RR100 ms might be a good indicator of the therapeutic potential of a retinal electrical prosthesis.

  15. Ganglion cyst arising from the composite occipito-atlanto-axial joint cavity in a cat.

    PubMed

    Aikawa, T; Sadahiro, S; Nishimura, M; Miyazaki, Y; Shibata, M

    2014-01-01

    A four-year-old, female spayed Domestic Longhaired cat was referred for evaluation with a two month history of initial inability to jump progressing to ambulatory tetraparesis. Magnetic resonance imaging studies demonstrated a cystic lesion arising from the composite occipito-atlanto-axial joint cavity and extending to the region of the occipital bone and the axis. The lesion surrounded the spinal canal, causing moderate dorsal spinal cord compression at the atlanto-occipital joint. A dynamic myelographic study demonstrated attenuation of the dorsal contrast column at the atlanto-occipital joint when the cervical spine was positioned in extension. Partial excision of the cyst capsule by a ventral approach resulted in long-term (64 months) resolution of clinical signs. Histological evaluation was consistent with a ganglion cyst. An intra-spinal ganglion cyst arising from the composite occipito-atlanto-axial joint cavity may be considered as an uncommon differential diagnosis for cats with cervical myelopathy.

  16. Divisive suppression explains high-precision firing and contrast adaptation in retinal ganglion cells

    PubMed Central

    Cui, Yuwei; Wang, Yanbin V; Park, Silvia J H; Demb, Jonathan B; Butts, Daniel A

    2016-01-01

    Visual processing depends on specific computations implemented by complex neural circuits. Here, we present a circuit-inspired model of retinal ganglion cell computation, targeted to explain their temporal dynamics and adaptation to contrast. To localize the sources of such processing, we used recordings at the levels of synaptic input and spiking output in the in vitro mouse retina. We found that an ON-Alpha ganglion cell's excitatory synaptic inputs were described by a divisive interaction between excitation and delayed suppression, which explained nonlinear processing that was already present in ganglion cell inputs. Ganglion cell output was further shaped by spike generation mechanisms. The full model accurately predicted spike responses with unprecedented millisecond precision, and accurately described contrast adaptation of the spike train. These results demonstrate how circuit and cell-intrinsic mechanisms interact for ganglion cell function and, more generally, illustrate the power of circuit-inspired modeling of sensory processing. DOI: http://dx.doi.org/10.7554/eLife.19460.001 PMID:27841746

  17. Suppressive actions of betaxolol on ionic currents in retinal ganglion cells may explain its neuroprotective effects.

    PubMed

    Hirooka, K; Kelly, M E; Baldridge, W H; Barnes, S

    2000-05-01

    Betaxolol, a beta 1-selective adrenoceptor antagonist, is widely used in the treatment of glaucoma. In addition to its ocular hypotensive effects, betaxolol has been suggested to act as a retinal neuroprotective agent (Osborne et al., 1997). To investigate possible mechanisms underlying the neuroprotective effects, we tested the actions of betaxolol on ion channels and calcium signaling in isolated retinal ganglion cells. Betaxolol (50 microM) reduced by about 20% the high-voltage-activated (HVA) Ca channel currents in ganglion cells isolated from tiger salamander retina. In contrast, the beta 1-adrenoceptor antagonists propranolol (10 microM) and timolol (50 microM) had no inhibitory actions on HVA Ca channel currents. The L-type Ca channel antagonist, nisoldipine, blocked the HVA Ca channel current partially and the remaining current was not inhibited by betaxolol. Outward current was inhibited in the presence of betaxolol. Both iberiotoxin (IBTX; 10 nM), a selective inhibitor of large-conductance Ca-activated K channels, and Cd2+ (100 microM), which suppresses Ca-activated K channels subsequent to its block of Ca channels, reduced outward current and the remaining current was not blocked significantly with betaxolol. In the presence of betaxolol, Na channel currents were reduced by about 20%, as were currents evoked by glutamate (10 mM) and GABA (1 mM). Current clamp recordings from isolated ganglion cells showed that betaxolol had several effects on excitability: spike height decreased, repetitive spike activity was suppressed, spike width increased and hyperpolarization following spikes was reduced. Calcium imaging in isolated rat retinal ganglion cells revealed that betaxolol inhibited glutamate-induced increases in [Ca2+]i. These results suggest that betaxolol has a diversity of suppressive actions on ganglion cell ion channels and that, as a consequence, one of the net actions of the drug is to reduce Ca2+ influx. The subsequent reduction in [Ca2+]i may

  18. Dopamine modulates carotid nerve responses induced by acetylcholine on the cat petrosal ganglion in vitro.

    PubMed

    Alcayaga, J; Varas, R; Arroyo, J; Iturriaga, R; Zapata, P

    1999-06-12

    We have recently reported that application of acetylcholine (ACh) or nicotine to the petrosal ganglion-the sensory ganglion of the glossopharyngeal nerve-elicits a burst of discharges in the carotid nerve branch, innervating the carotid body and sinus, but not in the glossopharyngeal branch, innervating the tongue and pharynx. Thus, the perikarya of sensory neurons for the carotid bifurcation exhibit selective cholinosensitivity. Since dopamine (DA) modulates carotid nerve chemosensory activity, we searched for the presence of DA sensitivity at the perikarya of these neurons in the cat petrosal ganglion superfused in vitro. Applications of DA in doses of up to 5 mg to the ganglion did not modify the rate of spontaneous discharges in the carotid nerve. However, if DA was applied 30 s before ACh injections, ACh-evoked reactions were modified: low doses of DA enhanced the subsequent responses to ACh, while high doses of DA depressed the responses to ACh. This depressant effect of DA on ACh responses was partially antagonized by adding spiroperone to the superfusate. Our results show that the response to ACh of petrosal ganglion neurons projecting through the carotid nerve is modulated by DA acting on D(2) receptors located in the somata of these neurons. Thus, dopaminergic modulation of cholinosensitivity could be shared also by the membranes of peripheral endings and perikarya of primary sensory neurons involved in arterial chemoreception.

  19. Structural analysis of retinal photoreceptor ellipsoid zone and postreceptor retinal layer associated with visual acuity in patients with retinitis pigmentosa by ganglion cell analysis combined with OCT imaging

    PubMed Central

    Liu, Guodong; Li, Hui; Liu, Xiaoqiang; Xu, Ding; Wang, Fang

    2016-01-01

    Abstract The aim of this study was to examine changes in photoreceptor ellipsoid zone (EZ) and postreceptor retinal layer in retinitis pigmentosa (RP) patients by ganglion cell analysis (GCA) combined with optical coherence tomography (OCT) imaging to evaluate the structure–function relationships between retinal layer changes and best corrected visual acuity (BCVA). Sixty-eight eyes of 35 patients with RP and 65 eyes of 35 normal controls were analyzed in the study. The average length of EZ was 911.1 ± 208.8 μm in RP patients, which was shortened with the progression of the disease on the OCT images. The average ganglion cell–inner plexiform layer thickness (GCIPLT) was 54.7 ± 18.9 μm in RP patients, while in normal controls it was 85.6 ± 6.8 μm. The GCIPLT in all quarters became significantly thinner along with outer retinal thinning. There was a significantly positive correlation between BCVA and EZ (r = −0.7622, P < 0.001) and GCIPLT (r = −0.452, P < 0.001). Therefore, we assess the retinal layer changes from a new perspective in RP patients, which suggests that EZ and GCIPLT obtained by GCA combined with OCT imaging are the direct and valid indicators to diagnosis and predict the pathological process of RP. PMID:28033301

  20. Activation of retinal ganglion cells following epiretinal electrical stimulation with hexagonally arranged bipolar electrodes

    NASA Astrophysics Data System (ADS)

    Abramian, Miganoosh; Lovell, Nigel H.; Morley, John W.; Suaning, Gregg J.; Dokos, Socrates

    2011-06-01

    We investigated retinal ganglion cell (RGC) responses to epiretinal electrical stimulation delivered by hexagonally arranged bipolar (Hex) electrodes, in order to assess the feasibility of this electrode arrangement for future retinal implant devices. In vitro experiments were performed using rabbit retinal preparations, with results compared to a computational model of axonal stimulation. Single-unit RGC responses to electrical stimulation were recorded with extracellular microelectrodes. With 100 µs/phase biphasic pulses, the threshold charge densities were 24.0 ± 11.2 and 7.7 ± 3.2 µC cm-2 for 50 and 125 µm diameter Hex electrodes, respectively. Threshold profiles and response characteristics strongly suggested that RGC axons were the neural activation site. Both the model and in vitro data indicated that localized tissue stimulation is achieved with Hex electrodes.

  1. Scene from above: retinal ganglion cell topography and spatial resolving power in the giraffe (Giraffa camelopardalis).

    PubMed

    Coimbra, João Paulo; Hart, Nathan S; Collin, Shaun P; Manger, Paul R

    2013-06-15

    The giraffe (Giraffa camelopardalis) is a browser that uses its extensible tongue to selectively collect leaves during foraging. As the tallest extant terrestrial mammal, its elevated head height provides panoramic surveillance of the environment. These aspects of the giraffe's ecology and phenotype suggest that vision is of prime importance. Using Nissl-stained retinal wholemounts and stereological methods, we quantitatively assessed the retinal specializations in the ganglion cell layer of the giraffe. The mean total number of retinal ganglion cells was 1,393,779 and their topographic distribution revealed the presence of a horizontal visual streak and a temporal area. With a mean peak of 14,271 cells/mm(2), upper limits of spatial resolving power in the temporal area ranged from 25 to 27 cycles/degree. We also observed a dorsotemporal extension (anakatabatic area) that tapers toward the nasal retina giving rise to a complete dorsal arch. Using neurofilament-200 immunohistochemistry, we also detected a dorsal arch formed by alpha ganglion cells with density peaks in the temporal (14-15 cells/mm(2)) and dorsonasal (10 cells/mm(2)) regions. As with other artiodactyls, the giraffe shares the presence of a horizontal streak and a temporal area which, respectively, improve resolution along the horizon and in the frontal visual field. The dorsal arch is related to the giraffe's head height and affords enhanced resolution in the inferior visual field. The alpha ganglion cell distribution pattern is unique to the giraffe and enhances acquisition of motion information for the control of tongue movement during foraging and the detection of predators.

  2. Seasonally Changing Cryptochrome 1b Expression in the Retinal Ganglion Cells of a Migrating Passerine Bird

    PubMed Central

    Nießner, Christine; Gross, Julia Christina; Denzau, Susanne; Peichl, Leo; Fleissner, Gerta; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2016-01-01

    Cryptochromes, blue-light absorbing proteins involved in the circadian clock, have been proposed to be the receptor molecules of the avian magnetic compass. In birds, several cryptochromes occur: Cryptochrome 2, Cryptochrome 4 and two splice products of Cryptochrome 1, Cry1a and Cry1b. With an antibody not distinguishing between the two splice products, Cryptochrome 1 had been detected in the retinal ganglion cells of garden warblers during migration. A recent study located Cry1a in the outer segments of UV/V-cones in the retina of domestic chickens and European robins, another migratory species. Here we report the presence of cryptochrome 1b (eCry1b) in retinal ganglion cells and displaced ganglion cells of European Robins, Erithacus rubecula. Immuno-histochemistry at the light microscopic and electron microscopic level showed eCry1b in the cell plasma, free in the cytosol as well as bound to membranes. This is supported by immuno-blotting. However, this applies only to robins in the migratory state. After the end of the migratory phase, the amount of eCry1b was markedly reduced and hardly detectable. In robins, the amount of eCry1b in the retinal ganglion cells varies with season: it appears to be strongly expressed only during the migratory period when the birds show nocturnal migratory restlessness. Since the avian magnetic compass does not seem to be restricted to the migratory phase, this seasonal variation makes a role of eCry1b in magnetoreception rather unlikely. Rather, it could be involved in physiological processes controlling migratory restlessness and thus enabling birds to perform their nocturnal flights. PMID:26953690

  3. Inhibition of Adult Rat Retinal Ganglion Cells by D1-type Dopamine Receptor Activation

    PubMed Central

    Hayashida, Yuki; Rodríguez, Carolina Varela; Ogata, Genki; Partida, Gloria J.; Oi, Hanako; Stradleigh, Tyler W.; Lee, Sherwin C.; Colado, Anselmo Felipe; Ishida, Andrew T.

    2011-01-01

    The spike output of neural pathways can be regulated by modulating output neuron excitability and/or their synaptic inputs. Dopaminergic interneurons synapse onto cells that route signals to mammalian retinal ganglion cells, but it is unknown whether dopamine can activate receptors in these ganglion cells and, if it does, how this affects their excitability. Here, we show D1a-receptor-like immunoreactivity in ganglion cells identified in adult rats by retrogradely transported dextran, and that dopamine, D1-type receptor agonists, and cAMP analogs inhibit spiking in ganglion cells dissociated from adult rats. These ligands curtailed repetitive spiking during constant current injections, and reduced the number and rate of rise of spikes elicited by fluctuating current injections without significantly altering the timing of the remaining spikes. Consistent with mediation by D1-type receptors, SCH-23390 reversed the effects of dopamine on spikes. Contrary to a recent report, spike inhibition by dopamine was not precluded by blocking Ih. Consistent with the reduced rate of spike rise, dopamine reduced voltage-gated Na+ current (INa) amplitude and tetrodotoxin, at doses that reduced INa as moderately as dopamine, also inhibited spiking. These results provide the first direct evidence that D1-type dopamine receptor activation can alter mammalian retinal ganglion cell excitability, and demonstrate that dopamine can modulate spikes in these cells by a mechanism different from the pre- and postsynaptic means proposed by previous studies. To our knowledge, our results also provide the first evidence that dopamine receptor activation can reduce excitability without altering the temporal precision of spike firing. PMID:19940196

  4. Impulse encoding across the dendritic morphologies of retinal ganglion cells.

    PubMed

    Sheasby, B W; Fohlmeister, J F

    1999-04-01

    Nerve impulse entrainment and other excitation and passive phenomena are analyzed for a morphologically diverse and exhaustive data set (n = 57) of realistic (3-dimensional computer traced) soma-dendritic tree structures of ganglion cells in the tiger salamander (Ambystoma tigrinum) retina. The neurons, including axon and an anatomically specialized thin axonal segment that is observed in every ganglion cell, were supplied with five voltage- or ligand-gated ion channels (plus leakage), which were distributed in accordance with those found in a recent study that employed an equivalent dendritic cylinder. A wide variety of impulse-entrainment responses was observed, including regular low-frequency firing, impulse doublets, and more complex patterns involving impulse propagation failures (or aborted spikes) within the encoder region, all of which have been observed experimentally. The impulse-frequency response curves of the cells fell into three groups called FAST, MEDIUM, and SLOW in approximate proportion as seen experimentally. In addition to these, a new group was found among the traced cells that exhibited an impulse-frequency response twice that of the FAST category. The total amount of soma-dendritic surface area exhibited by a given cell is decisive in determining its electrophysiological classification. On the other hand, we found only a weak correlation between the electrophysiological group and the morphological classification of a given cell, which is based on the complexity of dendritic branching and the physical reach or "receptive field" area of the cell. Dendritic morphology determines discharge patterns to dendritic (synaptic) stimulation. Orthodromic impulses can be initiated on the axon hillock, the thin axonal segment, the soma, or even the proximal axon beyond the thin segment, depending on stimulus magnitude, soma-dendritic membrane area, channel distribution, and state within the repetitive impulse cycle. Although a sufficiently high dendritic

  5. Response variability to high rates of electric stimulation in retinal ganglion cells

    PubMed Central

    Cai, Changsi; Ren, Qiushi; Desai, Neal J.; Rizzo, Joseph F.

    2011-01-01

    To improve the quality of prosthetic vision, it is important to understand how retinal neurons respond to electric stimulation. Previous studies present conflicting reports as to the maximum rate at which retinal ganglion cells can “follow” pulse trains, i.e., generate one spike for each pulse of the train. In the present study, we measured the response of 5 different types of rabbit retinal ganglion cells to pulse trains of 100–700 Hz. Surprisingly, we found significant heterogeneity in the ability of different types to follow pulse trains. For example, brisk transient (BT) ganglion cells could reliably follow pulse rates up to 600 pulses per second (PPS). In contrast, other types could not even follow rates of 200 PPS. There was additional heterogeneity in the response patterns across those types that could not follow high-rate trains. For example, some types generated action potentials in response to approximately every other pulse, whereas other types generated one spike per pulse for a few consecutive pulses and then did not generate any spikes in response to the next few pulses. Interestingly, in the types that could not follow high-rate trains, we found a second type of response: many pulses of the train elicited a biphasic waveform with an amplitude much smaller than that of standard action potentials. This small waveform was often observed following every pulse for which a standard spike was not elicited. A possible origin of the small waveform and its implication for effective retinal stimulation are discussed. PMID:21490287

  6. Influence of the sodium channel band on retinal ganglion cell excitation during electric stimulation - A modeling study

    PubMed Central

    Werginz, P.; Fried, S. I.; Rattay, F.

    2015-01-01

    Electric stimulation using retinal implants allows blind people to re-experience a rudimentary kind of vision. The elicited percepts or so called ’phosphenes’ are highly inconstant and therefore do not restore vision properly. The better knowledge of how retinal neurons, especially retinal ganglion cells, respond to electric stimulation will help to develop more sophisticated stimulation strategies. Special anatomic and physiologic properties like a band of highly dense sodium channels in retinal ganglion cells may help to achieve a focal activation of target cells and as a result better restoration of vision. A portion of retinal ganglion cell axons, about 40 μm from the soma and between 25 and 40μm in length, shows a specific biophysical property. Electrode locations close to a band of highly dense sodium channels which was identified immunochemically show lowest thresholds during electric stimulation. The (modeled) thresholds for this kind of structure result in lowest thresholds as well. The influence on the location where action potentials are generated within the axon is far reaching. When a stimulating electrode is positioned far outside the actual band region the site of spike initiation still remains within the sodium channel band. These findings suggest to further examine the key mechanisms of activation for retinal ganglion cells because focal activation without influencing passing axons of neurons located far away can improve the outcome of electric stimulation and therefore the development of retinal implants. PMID:24560986

  7. A computational model of electrical stimulation of the retinal ganglion cell.

    PubMed

    Greenberg, R J; Velte, T J; Humayun, M S; Scarlatis, G N; de Juan, E

    1999-05-01

    Localized retinal electrical stimulation in blind volunteers results in discrete round visual percepts corresponding to the location of the stimulating electrode. The success of such an approach to provide useful vision depends on elucidating the neuronal target of surface electrical stimulation. To determine if electrodes preferentially stimulate ganglion cells directly below them or passing fibers from distant ganglion cells, we developed a compartmental model for electric field stimulation of the retinal ganglion cell (RGC). In this model a RGC is stimulated by extracellular electrical fields with active channels and realistic cell morphology derived directly from a neuronal tracing. Three membrane models were applied: a linear passive model, a Hodgkin-Huxley model with passive dendrites (HH), and a model composed of all active compartments (FCM) with five nonlinear ion channels. Idealized monopolar point and disk stimulating electrodes were positioned above the cell. For the HH and FCM models, the position of lowest cathodal threshold to propagate an action potential was over the soma. Brief (100 microseconds) cathodic stimuli were 20% (HH with disk electrode) to 73% (FCM with point-source) more effective over the soma than over the axon. In the passive model, the axon is preferentially stimulated versus the soma. Although it may be possible to electrically stimulate RGC's near their cell body at lower thresholds than at their axon, these differences are relatively small. Alternative explanations should be sought to explain the focal perceptions observed in previously reported patient trials.

  8. The sensitivity of light-evoked responses of retinal ganglion cells is decreased in nitric oxide synthase gene knockout mice.

    PubMed

    Wang, Guo-Yong; van der List, Deborah A; Nemargut, Joseph P; Coombs, Julie L; Chalupa, Leo M

    2007-11-30

    We have shown previously that increasing the production of nitric oxide (NO) results in a dampening of visual responses of retinal ganglion cells (G. Y. Wang, L. C. Liets, & L. M. Chalupa, 2003). To gain further insights into the role of NO in retinal function, we made whole-cell patch clamp recordings from ganglion cells of neural type nitric oxide synthase (nNOS) gene knockout mice. Here we show that in the dark-adapted state, the sensitivity of retinal ganglion cell to light stimulation is decreased in nNOS knockout animals. The lowest light intensities required to evoke optimal responses and the average intensities that evoked half-maximal responses were significantly higher in nNOS knockouts than in normal mice. Retinal histology and other features of light-evoked responses of ganglion cells in nNOS mice appeared to be indistinguishable from those of normal mice. Collectively, these results, in conjunction with our previous work, provide evidence that increasing levels of NO dampen visual responses of ganglion cells, while a lack of nNOS decreases the sensitivity of these neurons to light. Thus, NO levels in the retina are capable of modulating the information that ganglion cells convey to the visual centers of the brain.

  9. Human amniotic fluid promotes retinal pigmented epithelial cells' trans-differentiation into rod photoreceptors and retinal ganglion cells.

    PubMed

    Ghaderi, Shima; Soheili, Zahra-Soheila; Ahmadieh, Hamid; Davari, Maliheh; Jahromi, Fatemeh Sanie; Samie, Shahram; Rezaie-Kanavi, Mozhgan; Pakravesh, Jalil; Deezagi, Abdolkhalegh

    2011-09-01

    To evaluate the effect of human amniotic fluid (HAF) on retinal pigmented epithelial cells growth and trans-differentiation into retinal neurons, retinal pigmented epithelium (RPE) cells were isolated from neonatal human cadaver eye globes and cultured in Dulbecco's modified Eagle's medium-F12 supplemented with 10% fetal bovine serum (FBS). Confluent monolayer cultures were trypsinized and passaged using FBS-containing or HAF-containing media. Amniotic fluid samples were received from pregnant women in the first trimester of gestation. Cell proliferation and death enzyme-linked immunosorbent assays were performed to assess the effect of HAF on RPE cell growth. Trans-differentiation into rod photoreceptors and retinal ganglion cells was also studied using immunocytochemistry and real-time polymerase chain reaction techniques. Primary cultures of RPE cells were successfully established under FBS-containing or HAF-containing media leading to rapid cell growth and proliferation. When RPE cells were moved to in vitro culture system, they began to lose their differentiation markers such as pigmentation and RPE65 marker and trans-differentiated neural-like cells followed by spheroid colonies pertaining to stem/progenitor cells were morphologically detected. Immunocytochemistry (ICC) analysis of HAF-treated cultures showed a considerable expression of Rhodopsin gene (30% Rhodopsin-positive cells) indicating trans-differentiation of RPE cells to rod photoreceptors. Real-time polymerase chain reaction revealed an HAF-dose-dependant expression of Thy-1 gene (RGC marker) and significant promoting effect of HAF on RGCs generation. The data presented here suggest that HAF possesses invaluable stimulatory effect on RPE cells growth and trans-differentiation into retinal neurons. It can be regarded as a newly introduced enriched supplement in serum-free kinds of media used in neuro-retinal regeneration studies.

  10. Activity of retinal ganglion cells following intense, nanosecond laser flashes. Final report, 1983-1986

    SciTech Connect

    Glickman, R.D.

    1989-01-01

    The effects of intense, but nonlesion-producing, laser exposures of 20-ns duration were determined on the light responses and spontaneous activity of retinal ganglion cells recorded in situ from the rhesus monkey. (Following a single, 20-ns exposure centered on its receptive field, a ganglion cell produced an 'afterdischarge' of maintained action potentials). The duration of the afterdischarge depended on the diameter of the laser beam on the retina and on the beam's intensity. Laser exposures subtending 0.5 to 2.0 deg, and delivering 45 to 60% of the maximum permissible exposure, elicited afterdischarges that lasted up to 80 s. When the beam diameter was decreased to 0.25 deg, the afterdischarge was reduced to 30 s, and to less than 5 s with the 0.12-deg beam. Light sensitivity after the laser exposure recovered rapidly during the first 10 s and then more slowly, but exponentially, until it reached the preflash level. Color-opponent ganglion cells exhibited a phenomenon called 'response-reversal' after the laser exposure, presumably due to selective adaptation of a mid-wavelength cone-input. Because a 20-ns exposure, regardless of intensity, is likely to photoregenerate more than half of the available visual pigment, the effects of ganglion cell response described here are not likely to be due solely to pigment bleaching.

  11. Somatic tetraploidy in specific chick retinal ganglion cells induced by nerve growth factor

    PubMed Central

    Morillo, Sandra M.; Escoll, Pedro; de la Hera, Antonio; Frade, José M.

    2009-01-01

    A subset of neurons in the normal vertebrate nervous system contains double the normal amount of DNA in their nuclei. These neurons are all thought to derive from aberrant mitoses in neuronal precursor cells. Here we show that endogenous NGF induces DNA replication in a subpopulation of differentiating chick retinal ganglion cells that express both the neurotrophin receptor p75 and the E2F1 transcription factor, but that lack the retinoblastoma protein. Many of these neurons avoid G2/M transition and remain alive in the retina as tetraploid cells with large cell somas and extensive dendritic trees, and most of them express β2 nicotinic acetylcholine receptor subunits, a specific marker of retinal ganglion cells innervating lamina F in the stratum-griseum-et-fibrosum-superficiale of the tectal cortex. Tetraploid neurons were also observed in the adult mouse retina. Thus, a developmental program leading to somatic tetraploidy in specific retinal neurons exists in vertebrates. This program might occur in other vertebrate neurons during normal or pathological situations. PMID:20018664

  12. The sodium channel band shapes the response to electric stimulation in retinal ganglion cells

    PubMed Central

    Jeng, J; Tang, S; Molnar, A; Desai, N J; Fried, S I

    2011-01-01

    To improve the quality of prosthetic vision, it is desirable to understand how targeted retinal neurons respond to stimulation. Unfortunately, the factors that shape the response of a single neuron to stimulation are not well understood. A dense band of voltage gated sodium channels within the proximal axon of retinal ganglion cells is the site most sensitive to electric stimulation, suggesting that band properties are likely to influence the response to stimulation. Here, we examined how three band properties influence sensitivity using a morphologically realistic ganglion cell model in NEURON. Longer bands were more sensitive to short-duration pulses than shorter bands and increasing the distance between band and soma also increased sensitivity. Simulations using the known limits of band length and location resulted in a sensitivity difference of approximately two. Additional simulations tested how changes to sodium channel conductance within the band influenced threshold and found that the sensitivity difference increased to a factor of nearly three. This is close to the factor of 5 difference measured in physiological studies suggesting that band properties contribute significantly to the sensitivity differences found between different types of retinal neurons. PMID:21558602

  13. The sodium channel band shapes the response to electric stimulation in retinal ganglion cells

    NASA Astrophysics Data System (ADS)

    Jeng, J.; Tang, S.; Molnar, A.; Desai, N. J.; Fried, S. I.

    2011-06-01

    To improve the quality of prosthetic vision, it is desirable to understand how targeted retinal neurons respond to stimulation. Unfortunately, the factors that shape the response of a single neuron to stimulation are not well understood. A dense band of voltage-gated sodium channels within the proximal axon of retinal ganglion cells is the site most sensitive to electric stimulation, suggesting that band properties are likely to influence the response to stimulation. Here, we examined how three band properties influence sensitivity using a morphologically realistic ganglion cell model in NEURON. Longer bands were more sensitive to short-duration pulses than shorter bands and increasing the distance between band and soma also increased sensitivity. Simulations using the known limits of band length and location resulted in a sensitivity difference of approximately 2. Additional simulations tested how changes to sodium channel conductance within the band influenced threshold and found that the sensitivity difference increased to a factor of nearly 3. This is close to the factor of 5 difference measured in physiological studies suggesting that band properties contribute significantly to the sensitivity differences found between different types of retinal neurons.

  14. Calpain Inhibition Attenuates Apoptosis of Retinal Ganglion Cells in Acute Optic Neuritis

    PubMed Central

    Smith, Amena W.; Das, Arabinda; Guyton, M. Kelly; Ray, Swapan K.; Rohrer, Baerbel

    2011-01-01

    Purpose. Optic neuritis (ON), inflammation of the optic nerve, is strongly associated with the pathogenesis of multiple sclerosis (MS) and is initiated by the attack of autoreactive T cells against self-myelin antigens, resulting in demyelination, degeneration of retinal ganglion cells (RGCs), and cumulative visual impairment. Methods. Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats on day 0, and animals received daily intraperitoneal injections of calpain inhibitor (calpeptin) or vehicle from day 1 until killed. Retinal cell death was analyzed by DNA fragmentation, and surviving ganglion cells were quantified after double labeling of retinal tissue with TUNEL and Brn3a. The expression of apoptotic and inflammatory proteins was determined by Western blotting. Results. It was demonstrated that calpain inhibition downregulates expression of proapoptotic proteins and the proinflammatory molecule nuclear factor-kappa B (NF-κB) in the retina of Lewis rats with acute EAE. Immunofluorescent labeling revealed that apoptotic cells in the RGC layer of vehicle-treated EAE animals were Brn3a positive, and a moderate dose of calpeptin dramatically reduced the frequency of apoptotic RGCs. Conclusions. These results suggest that calpain inhibition might be a useful supplement to immunomodulatory therapies such as corticosteroids in ON, due to its neuroprotective effect on RGCs. PMID:21613375

  15. Topographic prominence discriminator for the detection of short-latency spikes of retinal ganglion cells.

    PubMed

    Choi, Myoung-Hwan; Ahn, Jungryul; Park, Dae Jin; Lee, Sang Min; Kim, Kwangsoo; Cho, Dong-Il Dan; Senok, Solomon S; Koo, Kyo-In; Goo, Yong Sook

    2017-02-01

    Direct stimulation of retinal ganglion cells in degenerate retinas by implanting epi-retinal prostheses is a recognized strategy for restoration of visual perception in patients with retinitis pigmentosa or age-related macular degeneration. Elucidating the best stimulus-response paradigms in the laboratory using multielectrode arrays (MEA) is complicated by the fact that the short-latency spikes (within 10 ms) elicited by direct retinal ganglion cell (RGC) stimulation are obscured by the stimulus artifact which is generated by the electrical stimulator. We developed an artifact subtraction algorithm based on topographic prominence discrimination, wherein the duration of prominences within the stimulus artifact is used as a strategy for identifying the artifact for subtraction and clarifying the obfuscated spikes which are then quantified using standard thresholding. We found that the prominence discrimination based filters perform creditably in simulation conditions by successfully isolating randomly inserted spikes in the presence of simple and even complex residual artifacts. We also show that the algorithm successfully isolated short-latency spikes in an MEA-based recording from degenerate mouse retinas, where the amplitude and frequency characteristics of the stimulus artifact vary according to the distance of the recording electrode from the stimulating electrode. By ROC analysis of false positive and false negative first spike detection rates in a dataset of one hundred and eight RGCs from four retinal patches, we found that the performance of our algorithm is comparable to that of a generally-used artifact subtraction filter algorithm which uses a strategy of local polynomial approximation (SALPA). We conclude that the application of topographic prominence discrimination is a valid and useful method for subtraction of stimulation artifacts with variable amplitudes and shapes. We propose that our algorithm may be used as stand-alone or supplementary to

  16. Topographic prominence discriminator for the detection of short-latency spikes of retinal ganglion cells

    NASA Astrophysics Data System (ADS)

    Choi, Myoung-Hwan; Ahn, Jungryul; Park, Dae Jin; Lee, Sang Min; Kim, Kwangsoo; Cho, Dong-il Dan; Senok, Solomon S.; Koo, Kyo-in; Goo, Yong Sook

    2017-02-01

    Objective. Direct stimulation of retinal ganglion cells in degenerate retinas by implanting epi-retinal prostheses is a recognized strategy for restoration of visual perception in patients with retinitis pigmentosa or age-related macular degeneration. Elucidating the best stimulus-response paradigms in the laboratory using multielectrode arrays (MEA) is complicated by the fact that the short-latency spikes (within 10 ms) elicited by direct retinal ganglion cell (RGC) stimulation are obscured by the stimulus artifact which is generated by the electrical stimulator. Approach. We developed an artifact subtraction algorithm based on topographic prominence discrimination, wherein the duration of prominences within the stimulus artifact is used as a strategy for identifying the artifact for subtraction and clarifying the obfuscated spikes which are then quantified using standard thresholding. Main results. We found that the prominence discrimination based filters perform creditably in simulation conditions by successfully isolating randomly inserted spikes in the presence of simple and even complex residual artifacts. We also show that the algorithm successfully isolated short-latency spikes in an MEA-based recording from degenerate mouse retinas, where the amplitude and frequency characteristics of the stimulus artifact vary according to the distance of the recording electrode from the stimulating electrode. By ROC analysis of false positive and false negative first spike detection rates in a dataset of one hundred and eight RGCs from four retinal patches, we found that the performance of our algorithm is comparable to that of a generally-used artifact subtraction filter algorithm which uses a strategy of local polynomial approximation (SALPA). Significance. We conclude that the application of topographic prominence discrimination is a valid and useful method for subtraction of stimulation artifacts with variable amplitudes and shapes. We propose that our algorithm

  17. Selective activation of carotid nerve fibers by acetylcholine applied to the cat petrosal ganglion in vitro.

    PubMed

    Alcayaga, J; Iturriaga, R; Varas, R; Arroyo, J; Zapata, P

    1998-03-09

    The petrosal ganglion innervates carotid body chemoreceptors through the carotid (sinus) nerve. These primary sensory neurons are activated by transmitters released from receptor (glomus) cells, acetylcholine (ACh) having been proposed as one of the transmitters involved in this process. Since the perikarya of primary sensory neurons share several properties with peripheral sensory endings, we studied the electrical responses of the carotid nerve and glossopharyngeal branch to ACh locally applied to the cat petrosal ganglion superfused in vitro. Ganglionar applications of AChCl (1 microg-1 mg) generated bursts of action potentials conducted along the carotid nerve, while only a few spikes were exceptionally recorded from the glossopharyngeal branch in response to the largest doses. Carotid nerve responses to ACh were dose-dependent, the higher doses inducing transient desensitization. Application of nicotine to the petrosal ganglion also evoked dose-dependent excitatory responses in the carotid nerve. Responses to ACh were reversibly antagonized by adding hexamethonium to the superfusate, more intense and prolonged block of ACh responses being produced by mecamylamine. Ganglionar applications of gamma-amino butyric acid and serotonin, in doses of up to 5 mg, did not induce firing of action potentials in any of the branches of the glossopharyngeal nerve. Our results indicate that petrosal ganglion neurons projecting through the carotid nerve are selectively activated by ACh acting on nicotinic ACh receptors located in the somata of these neurons. Thus, cholinosensitivity would be shared by the membranes of peripheral endings and perikarya of primary sensory neurons involved in arterial chemoreception.

  18. Spontaneous Oscillatory Rhythms in the Degenerating Mouse Retina Modulate Retinal Ganglion Cell Responses to Electrical Stimulation.

    PubMed

    Goo, Yong Sook; Park, Dae Jin; Ahn, Jung Ryul; Senok, Solomon S

    2015-01-01

    Characterization of the electrical activity of the retina in the animal models of retinal degeneration has been carried out in part to understand the progression of retinal degenerative diseases like age-related macular degeneration (AMD) and retinitis pigmentosa (RP), but also to determine optimum stimulus paradigms for use with retinal prosthetic devices. The models most studied in this regard have been the two lines of mice deficient in the β-subunit of phosphodiesterase (rd1 and rd10 mice), where the degenerating retinas exhibit characteristic spontaneous hyperactivity and oscillatory local field potentials (LFPs). Additionally, there is a robust ~10 Hz rhythmic burst of retinal ganglion cell (RGC) spikes on the trough of the oscillatory LFP. In rd1 mice, the rhythmic burst of RGC spikes is always phase-locked with the oscillatory LFP and this phase-locking property is preserved regardless of postnatal ages. However, in rd10 mice, the frequency of the oscillatory rhythm changes according to postnatal age, suggesting that this rhythm might be a marker of the stage of degeneration. Furthermore when a biphasic current stimulus is applied to rd10 mice degenerate retina, distinct RGC response patterns that correlate with the stage of degeneration emerge. This review also considers the significance of these response properties.

  19. Spontaneous Oscillatory Rhythms in the Degenerating Mouse Retina Modulate Retinal Ganglion Cell Responses to Electrical Stimulation

    PubMed Central

    Goo, Yong Sook; Park, Dae Jin; Ahn, Jung Ryul; Senok, Solomon S.

    2016-01-01

    Characterization of the electrical activity of the retina in the animal models of retinal degeneration has been carried out in part to understand the progression of retinal degenerative diseases like age-related macular degeneration (AMD) and retinitis pigmentosa (RP), but also to determine optimum stimulus paradigms for use with retinal prosthetic devices. The models most studied in this regard have been the two lines of mice deficient in the β-subunit of phosphodiesterase (rd1 and rd10 mice), where the degenerating retinas exhibit characteristic spontaneous hyperactivity and oscillatory local field potentials (LFPs). Additionally, there is a robust ~10 Hz rhythmic burst of retinal ganglion cell (RGC) spikes on the trough of the oscillatory LFP. In rd1 mice, the rhythmic burst of RGC spikes is always phase-locked with the oscillatory LFP and this phase-locking property is preserved regardless of postnatal ages. However, in rd10 mice, the frequency of the oscillatory rhythm changes according to postnatal age, suggesting that this rhythm might be a marker of the stage of degeneration. Furthermore when a biphasic current stimulus is applied to rd10 mice degenerate retina, distinct RGC response patterns that correlate with the stage of degeneration emerge. This review also considers the significance of these response properties. PMID:26793063

  20. Extrasynaptic glutamate and inhibitory neurotransmission modulate ganglion cell participation during glutamatergic retinal waves.

    PubMed

    Firl, Alana; Sack, Georgeann S; Newman, Zachary L; Tani, Hiroaki; Feller, Marla B

    2013-04-01

    During the first 2 wk of mouse postnatal development, transient retinal circuits give rise to the spontaneous initiation and lateral propagation of depolarizations across the ganglion cell layer (GCL). Glutamatergic retinal waves occur during the second postnatal week, when GCL depolarizations are mediated by ionotropic glutamate receptors. Bipolar cells are the primary source of glutamate in the inner retina, indicating that the propagation of waves depends on their activation. Using the fluorescence resonance energy transfer-based optical sensor of glutamate FLII81E-1μ, we found that retinal waves are accompanied by a large transient increase in extrasynaptic glutamate throughout the inner plexiform layer. Using two-photon Ca(2+) imaging to record spontaneous Ca(2+) transients in large populations of cells, we found that despite this spatially diffuse source of depolarization, only a subset of neurons in the GCL and inner nuclear layer (INL) are robustly depolarized during retinal waves. Application of the glutamate transporter blocker dl-threo-β-benzyloxyaspartate (25 μM) led to a significant increase in cell participation in both layers, indicating that the concentration of extrasynaptic glutamate affects cell participation in both the INL and GCL. In contrast, blocking inhibitory transmission with the GABAA receptor antagonist gabazine and the glycine receptor antagonist strychnine increased cell participation in the GCL without significantly affecting the INL. These data indicate that during development, glutamate spillover provides a spatially diffuse source of depolarization, but that inhibitory circuits dictate which neurons within the GCL participate in retinal waves.

  1. Retinal ganglion cell distribution and visual acuity in alpacas (Vicugna pacos).

    PubMed

    Wang, Hsiao-Hui; Gallagher, Shannon K; Byers, Stacey R; Madl, James E; Gionfriddo, Juliet R

    2015-01-01

    To investigate the distribution of retinal ganglion cells (RGCs) and visual acuity in alpacas (Vicugna pacos) through Brn-3a immunofluorescent labeling. Five eyes from four healthy alpacas with normal ophthalmic examination findings were included in the study. The axial length of the globes was measured before fixation. All five retinas were treated with Brn-3a antibodies to label RGCs. Images taken with a fluorescent microscope were used for RGC counting. RGC density maps were reconstructed by computer software. Visual acuity was estimated based on the results of peak RGC density and ocular anatomical parameters. The reconstructed retinal maps from Brn-3a labeling showed a horizontal streak across the retinal meridian superior to the optic nerve head with a temporal, upward extension. The highest RGC densities were in the temporal retinas. The maximal visual acuity was located in the temporal retina and was estimated to range between 12.5 and 13.4 cycles per degree. Alpacas have a horizontal streak across the retinal meridian superior to the optic disk with a temporal, upward extension based on the Brn-3a labeling of RGCs. The maximal visual acuity was located in the temporal retina. The reconstructed retinal maps indicate the RGC topography of alpacas is similar to that of other herbivores, but is different from that of dromedary camels. © 2013 American College of Veterinary Ophthalmologists.

  2. Uniformity detector retinal ganglion cells fire complex spikes and receive only light-evoked inhibition

    PubMed Central

    Sivyer, Benjamin; Taylor, W. Rowland; Vaney, David I.

    2010-01-01

    Retinal ganglion cells convey information by increasing their firing in response to an optimal visual stimulus or “trigger feature.” However, one class of ganglion cell responds to changes in the visual scene by decreasing its firing. These cells, termed uniformity detectors in the rabbit retina, are encountered only rarely and the synaptic mechanisms underlying their unusual responses have not been investigated. In this study, patch-clamp recordings of uniformity detectors show that the action potentials underlying the maintained firing arise within “complex spikes.” Both ON and OFF visual stimuli elicit only inhibitory synaptic input, the immediate effect of which is to suppress the maintained firing. However, this inhibition also alters the properties of the “renascent” spiking by increasing the amplitude of the spikes within each burst, suggesting that the effect may increase the efficacy of spike propagation and transmission. PMID:20212117

  3. Uniformity detector retinal ganglion cells fire complex spikes and receive only light-evoked inhibition.

    PubMed

    Sivyer, Benjamin; Taylor, W Rowland; Vaney, David I

    2010-03-23

    Retinal ganglion cells convey information by increasing their firing in response to an optimal visual stimulus or "trigger feature." However, one class of ganglion cell responds to changes in the visual scene by decreasing its firing. These cells, termed uniformity detectors in the rabbit retina, are encountered only rarely and the synaptic mechanisms underlying their unusual responses have not been investigated. In this study, patch-clamp recordings of uniformity detectors show that the action potentials underlying the maintained firing arise within "complex spikes." Both ON and OFF visual stimuli elicit only inhibitory synaptic input, the immediate effect of which is to suppress the maintained firing. However, this inhibition also alters the properties of the "renascent" spiking by increasing the amplitude of the spikes within each burst, suggesting that the effect may increase the efficacy of spike propagation and transmission.

  4. Delayed rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells

    PubMed Central

    Weick, Michael; Demb, Jonathan B.

    2011-01-01

    SUMMARY Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5–10 mV) also suppressed firing during subsequent depolarization. This suppression was sensitive selectively to blockers of delayed-rectifier K channels (KDR). Somatic membrane patches showed TEA-sensitive KDR currents with activation near −25 mV and removal of inactivation at voltages negative to Vrest. Brief periods of hyperpolarization apparently remove KDR inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. PMID:21745646

  5. Neuroprotective effects of antibodies on retinal ganglion cells in an adolescent retina organ culture.

    PubMed

    Bell, Katharina; Wilding, Corina; Funke, Sebastian; Perumal, Natarajan; Beck, Sabine; Wolters, Dominik; Holz-Müller, Jana; Pfeiffer, Norbert; Grus, Franz H

    2016-10-01

    Glaucoma, a neurodegenerative disease, is characterized by a progressive loss of retinal ganglion cells (rgc). Up- and down-regulated autoantibody immunoreactivities in glaucoma patients have been demonstrated. Previous studies showed protective effects of down-regulated antibodies [gamma (γ)-synuclein and glial fibrillary acidic protein [GFAP]) on neuroretinal cells. The aim of this study was to test these protective antibody effects on rgc in an organ culture model and to get a better understanding of cell-cell interactions of the retina in the context of the protective effect. We used an adolescent retinal organ culture (pig) with an incubation time of up to 4 days. Retinal explants were incubated with different antibodies for 24 h (anti-GFAP, anti-γ-synuclein and anti-myoglobin antibody as a control). Brn3a and TUNEL staining were performed. We also conducted glutamine synthetase staining and quantification of the retinal explants. Mass spectrometry analyses were performed as well as protein analyses via microarray. We detected a continuous decrease of rgc/mm in the retinal explants throughout the 4 days of incubation with increased TUNEL rgc staining. Immunohistochemical analyses showed a protective effect of anti-γ-synuclein (increased rgc/mm of 41%) and anti-GFAP antibodies (increased rgc/mm of 37%). Mass spectrometric, microarray and immunohistochemical analyses demonstrated Müller cell involvement and decreased endoplasmic reticulum stress response in the antibody-treated retinae. We could detect that the tested antibodies have a protective effect on rgc which seems to be the result of reduced stress levels in the retina as well as a shift of glutamine synthetase localization in the endfeet of the Müller cells towards the inner retinal layer. Loss of retinal ganglion cells (rgc) in glaucoma leads to blindness. Several antibodies are down-regulated in glaucoma patients. Our aim was to test if these antibodies have a protective effect of rgc in a

  6. Retinal ganglion cell topography and spatial resolving power in the river hippopotamus (Hippopotamus amphibius).

    PubMed

    Coimbra, João Paulo; Bertelsen, Mads F; Manger, Paul R

    2017-08-01

    The river hippopotamus (Hippopotamus amphibius), one of the closest extant relatives to cetaceans, is a large African even-toed ungulate (Artiodactyla) that grazes and has a semiaquatic lifestyle. Given its unusual phenotype, ecology, and evolutionary history, we sought to measure the topographic distribution of retinal ganglion cell density using stereology and retinal wholemounts. We estimated a total of 243,000 ganglion cells of which 3.4% (8,300) comprise alpha cells. The topographic distribution of both total and alpha cells reveal a dual topographic organization of a temporal and nasal area embedded within a well-defined horizontal streak. Using maximum density of total ganglion cells and eye size (35 mm, axial length), we estimated upper limits of spatial resolving power of 8 cycles/deg (temporal area, 1,800 cells/mm(2) ), 7.7 cycles/deg (nasal area, 1,700 cells/mm(2) ), and 4.2 cycles/deg (horizontal streak, 250 cells/mm(2) ). Enhanced resolution of the temporal area toward the frontal visual field may facilitate grazing, while resolution of the horizontal streak and nasal area may help the discrimination of objects (predators, conspecifics) in the lateral and posterior visual fields, respectively. Given the presumed role of alpha cells to detect brisk transient stimuli, their similar distribution to the total ganglion cell population may facilitate the detection of approaching objects in equivalent portions of the visual field. Our finding of a nasal area in the river hippopotamus retina supports the notion that this specialization may enhance visual sampling in the posterior visual field to compensate for limited neck mobility as suggested for rhinoceroses and cetaceans. © 2017 Wiley Periodicals, Inc.

  7. Effects of cholinergic drugs on receptive field properties of rabbit retinal ganglion cells

    PubMed Central

    Ariel, M.; Daw, N. W.

    1982-01-01

    1. Retinal ganglion cells were recorded extracellularly from the rabbit's eye in situ to study the effects of cholinergic drugs on receptive field properties. Physostigmine, an acetylcholinesterase inhibitor, and nicotine increased the spontaneous activity of nearly all retinal ganglion cell types. The effectiveness of physostigmine was roughly correlated with the neurone's inherent level of spontaneous activity. Brisk cells, having high rates of spontaneous firing, showed large increases in their maintained discharge, whereas sluggish cells, with few or no spontaneous spikes, showed small and sometimes transient increases in spontaneous activity during physostigmine. 2. The sensitivity of ganglion cells to spots of optimal size and position did not change substantially during the infusion of physostigmine. However, the responsiveness to light (number of spikes per stimulus above the spontaneous level) increased. This effect occurred with sluggish and more complex cells, rarely with brisk cells. 3. Another effect of physostigmine on sluggish and more complex cells was to make these cells `on—off'. The additional response to the inappropriate change in contrast had a long latency and lacked an initial transient burst. 4. Complex receptive field properties such as orientation sensitivity, radial grating inhibition, speed tuning and size specificity were also examined. These inhibitory properties were still present during infusion of physostigmine and, in most cases, the trigger feature of each cell type remained. 5. These results are consistent with pharmacological results on ACh release from the retina. There appear to be two types of release of ACh, having their most powerful influences on separate classes of cells. One release (transient), occurs at light onset and offset and acts primarily on sluggish and more complex ganglion cells; the other release (tonic) is not light-modulated and acts primarily on brisk cells. A wiring diagram for the ACh cells is

  8. Channelrhodopsin-2 gene transduced into retinal ganglion cells restores functional vision in genetically blind rats.

    PubMed

    Tomita, Hiroshi; Sugano, Eriko; Isago, Hitomi; Hiroi, Teru; Wang, Zhuo; Ohta, Emi; Tamai, Makoto

    2010-03-01

    To test the hypothesis that transduction of the channelrhodopsin-2 (ChR2) gene, a microbial-type rhodopsin gene, into retinal ganglion cells of genetically blind rats will restore functional vision, we recorded visually evoked potentials and tested the experimental rats for the presence of optomotor responses. The N-terminal fragment of the ChR2 gene was fused to the fluorescent protein Venus and inserted into an adeno-associated virus to make AAV2-ChR2V. AAV2-ChR2V was injected intravitreally into the eyes of 6-month-old dystrophic RCS (rdy/rdy) rats. Visual function was evaluated six weeks after the injection by recording visually evoked potentials (VEPs) and testing optomotor responses. The expression of ChR2V in the retina was investigated histologically. We found that VEPs could not be recorded from 6-month-old dystrophic RCS rats that had not been injected with AAV2-ChR2V. In contrast, VEPs were elicited from RCS rats six weeks after injection with AAV2-ChR2V. The VEPs were recorded at stimulation rates <20Hz, which was the same as that of normal rats. Optomotor responses were also significantly better after the AAV2-ChR2V injection. Expression of ChR2V was observed mainly in the retinal ganglion cells. These findings demonstrate that visual function can be restored in blind rats by transducing the ChR2V gene into retinal ganglion cells.

  9. The trophic effect of ouabain on retinal ganglion cells is mediated by IL-1β and TNF-α

    SciTech Connect

    Salles von-Held-Ventura, Juliana; Mázala-de-Oliveira, Thalita; Cândida da Rocha Oliveira, Amanda; Granja, Marcelo Gomes; Giestal-de-Araujo, Elizabeth

    2016-09-09

    Ouabain is a steroid hormone that binds to the enzyme Na{sup +}, K{sup +} – ATPase and stimulates different intracellular pathways controlling growth, proliferation and cell survival. IL-1β and TNF-α are pleiotropic molecules, conventionally regarded as pro-inflammatory cytokines with well-known effects in the immune system. In addition, IL-1β and TNF-α also play important roles in the nervous system including neuroprotective effects. Previous data from our group showed that ouabain treatment is able to induce an increase in retinal ganglion cell survival kept in mixed retinal cell cultures. The aim of this work was to investigate if IL-1β and TNF-α could be mediating the trophic effect of ouabain on retinal ganglion cells. Our results show that the trophic effect of ouabain on retinal ganglion cell was inhibited by either anti-IL-1β or anti-TNF-α antibodies. In agreement, IL-1β or TNF-α increased the retinal ganglion cells survival in a dose-dependent manner. Accordingly, ouabain treatment induces a temporal release of TNF-α and IL-1β from retinal cell cultures. Interestingly, TNF-α and IL-1β regulate each other intracellular levels. Our results suggest that ouabain treatment triggers the activation of TNF-α and IL-1β signaling pathways leading to an increase in retinal ganglion cell survival. - Highlights: • Pro-inflammatory cytokines regulates the ouabain effect on RGC survival. • Ouabain treatment modulates the intracellular levels of TNF-α and IL-1β. • Ouabain induces the release of TNF-α and IL-1β in retinal cell cultures.

  10. Effect of stimulation of trigeminal ganglion on regional cerebral blood flow in cats

    SciTech Connect

    Goadsby, P.J.; Duckworth, J.W. )

    1987-08-01

    Regional cerebral blood flow was studied in the cat, with and without trigeminal ganglion stimulation, by the intravenous injection of the tracer ({sup 14}C)iodoantipyrine and subsequent regional brain dissection. Electrical activation of the trigeminal ganglion led to a selective increase in regional blood flow in the frontal and parietal cortex that was bilateral without change in the posterior cortex, deep cerebral nuclei, white matter, or brain stem. Unilateral intracranial section of the facial nerve blocked the response in the ipsilateral frontal and parietal cortex, whereas bilateral facial nerve section blocked the contralateral frontal cortical response. The contralateral parietal cortical increase in blood flow was not affected by facial nerve section and may thus represent the result of metabolic activation of sensory cortex.

  11. The pattern of retinal ganglion cell dysfunction in Leber hereditary optic neuropathy.

    PubMed

    Majander, A; Robson, A G; João, C; Holder, G E; Chinnery, P F; Moore, A T; Votruba, M; Stockman, A; Yu-Wai-Man, P

    2017-09-01

    Leber inherited optic neuropathy (LHON) is characterized by subacute bilateral loss of central vision due to dysfunction and loss of retinal ganglion cells (RGCs). Comprehensive visual electrophysiological investigations (including pattern reversal visual evoked potentials, pattern electroretinography and the photopic negative response) performed on 13 patients with acute and chronic LHON indicate early impairment of RGC cell body function and severe axonal dysfunction. Temporal, spatial and chromatic psychophysical tests performed on 7 patients with acute LHON and 4 patients with chronic LHON suggest severe involvement or loss of the midget, parasol and bistratified RGCs associated with all three principal visual pathways. Copyright © 2017. Published by Elsevier B.V.

  12. Selective labeling of retinal ganglion cells with calcium indicators by retrograde loading in vitro

    PubMed Central

    Behrend, Matthew R.; Ahuja, Ashish K.; Humayun, Mark S.; Weiland, James D.; Chow, Robert H.

    2012-01-01

    Here we present a retrograde loading technique that makes it possible for the first time to rapidly load a calcium indicator in the majority of retinal ganglion cells (RGCs) in salamander retina, and then to observe physiological activity of these dye-loaded cells. Dextran-conjugated calcium indicator, dissolved in water, was applied to the optic nerve stump. Following dye loading, the isolated retina was mounted on a microelectrode array to demonstrate that electrical activity and calcium activity were preserved, as the retina responded to electrical stimuli. PMID:19428523

  13. Selective labeling of retinal ganglion cells with calcium indicators by retrograde loading in vitro.

    PubMed

    Behrend, Matthew R; Ahuja, Ashish K; Humayun, Mark S; Weiland, James D; Chow, Robert H

    2009-05-15

    Here we present a retrograde loading technique that makes it possible for the first time to rapidly load a calcium indicator in the majority of retinal ganglion cells (RGCs) in salamander retina, and then to observe physiological activity of these dye-loaded cells. Dextran-conjugated calcium indicator, dissolved in water, was applied to the optic nerve stump. Following dye loading, the isolated retina was mounted on a microelectrode array to demonstrate that electrical activity and calcium activity were preserved, as the retina responded to electrical stimuli.

  14. Melanopsin-expressing retinal ganglion-cell photoreceptors: cellular diversity and role in pattern vision

    PubMed Central

    Ecker, Jennifer L.; Dumitrescu, Olivia N.; Wong, Kwoon Y.; Alam, Nazia M.; Chen, Shih-Kuo; LeGates, Tara; Renna, Jordan M.; Prusky, Glen T.; Berson, David M.; Hattar, Samer

    2010-01-01

    Using the photopigment melanopsin, intrinsically photosensitive retinal ganglion cells (ipRGCs) respond directly to light to drive circadian clock resetting and pupillary constriction. We now report that ipRGCs are more abundant and diverse than previously appreciated, project more widely within the brain, and can support spatial visual perception. A Cre-based melanopsin reporter mouse line revealed at least five subtypes of ipRGCs with distinct morphological and physiological characteristics. Collectively, these cells project beyond the known brain targets of ipRGCs to heavily innervate the superior colliculus and dorsal lateral geniculate nucleus, retinotopically-organized nuclei mediating object localization and discrimination. Mice lacking classical rod-cone photoreception, and thus entirely dependent on melanopsin for light detection, were able to discriminate grating stimuli from equiluminant gray, and had measurable visual acuity. Thus, non-classical retinal photoreception occurs within diverse cell types, and influences circuits and functions encompassing luminance as well as spatial information. PMID:20624591

  15. Neuronal Transcriptional Repressor REST Suppresses an Atoh7-Independent Program for Initiating Retinal Ganglion Cell Development

    PubMed Central

    Mao, Chai-An; Tsai, Wen-Wei; Cho, Jang-Hyeon; Pan, Ping; Barton, Michelle Craig; Klein, William H.

    2010-01-01

    As neuronal progenitors differentiate into neurons, they acquire a unique set of transcription factors. The transcriptional repressor REST prevents progenitors from undergoing differentiation. Notably, REST binding sites are often associated with retinal ganglion cell (RGC) genes whose expression in the retina is positively controlled by Atoh7, a factor essential for RGC formation. The key regulators that enable a retinal progenitor cell (RPC) to commit to an RGC fate have not been identified. We show here that REST suppresses RGC gene expression in RPCs. REST inactivation causes aberrant expression of RGC transcription factors in proliferating RPCs, independent of Atoh7, resulting in increased RGC formation. Strikingly, inactivating REST in Atoh7-null retinas restores transcription factor expression, which partially activates downstream RGC genes but is insufficient to prevent RGC loss. Our results demonstrate an Atoh7-independent program for initial activation of RGC genes and suggest a novel role for REST in preventing premature expression in RPCs. PMID:20969844

  16. Retinal ganglion cells in the Pacific redfin, Tribolodon brandtii dybowski, 1872: morphology and diversity.

    PubMed

    Pushchin, Igor; Karetin, Yuriy

    2014-04-15

    We studied the morphology and diversity of retinal ganglion cells in the Pacific redfin, Tribolodon brandtii. These cells were retrogradely labeled with horseradish peroxidase and examined in retinal whole mounts. A sample of 203 cells was drawn with a camera lucida. A total of 19 structural parameters were estimated for each cell, and a variety of clustering algorithms were used to classify the cells. The optimal solution was determined by using silhouette analysis. It was based on three variables associated with dendritic field size and dendrite stratification in the retina. Kruskal-Wallis ANOVA-on-ranks with post hoc Mann-Whitney U tests showed significant pairwise between-cluster differences in two or more of the original variables. In total, eight cell types were discovered. The advantages and drawbacks of the methodology adopted are discussed. The present classification is compared with classifications proposed for other teleosts.

  17. [The advances in research on precisely inducing retinal ganglion cells from stem cells].

    PubMed

    Li, K J; Zhu, M Y; Ge, J

    2017-05-11

    The injury and repair of retinal neurons is a common scientific problem in the occurrence, development and prognosis of neuronal visual impairment. Transplant of retinal ganglion cells (RGCs) differentiated from stem cells opens a new avenue for treatment of glaucoma and optic neuronal degenerative diseases. For the goal to explore the optimal method for RGCs replacement, this review summarizes the current information regarding the classification and application of stem cells, the growth characteristics of RGCs and the precise methods to induce RGCs, and discusses some important issues that need resolving and are related to RGCs transplantation. It is hoped that this article will provide useful theoretical basis for the research of this field. (Chin J Ophthalmol, 2017, 53: 381-385).

  18. Aberrant synaptic input to retinal ganglion cells varies with morphology in a mouse model of retinal degeneration

    PubMed Central

    Yee, Christopher W; Toychiev, Abduqodir H; Ivanova, Elena; Sagdullaev, Botir T

    2014-01-01

    Retinal degeneration describes a group of disorders which lead to progressive photoreceptor cell death, resulting in blindness. As this occurs, retinal ganglion cells (RGCs) begin to develop oscillatory physiological activity. Here, we studied the morphological and physiological properties of RGCs in rd1 mice, aged 30–60 days, to determine how this aberrant activity correlates with morphology. Patch-clamp recordings of excitatory and inhibitory currents were performed, then dendritic structures were visualized by infusion of fluorescent dye. Only RGCs with oscillatory activity were selected for further analysis. Oscillatory frequency and power were calculated using power spectral density analysis of recorded currents. Dendritic arbor stratification, total length, and area were measured from confocal microscope image stacks. These measurements were used to sort RGCs by cluster analysis using Ward’s method. This resulted in a total of 10 clusters, with monostratified and bistratified cells having 5 clusters each. Both populations exhibited correlations between arbor stratification and aberrant inhibitory input, while excitatory input did not vary with arbor distribution. These findings illustrate the relationship between aberrant activity and RGC morphology at early stages of retinal degeneration. PMID:25099614

  19. Caffeine administration prevents retinal neuroinflammation and loss of retinal ganglion cells in an animal model of glaucoma.

    PubMed

    Madeira, Maria H; Ortin-Martinez, Arturo; Nadal-Nícolas, Francisco; Ambrósio, António F; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta; Santiago, Ana Raquel

    2016-06-08

    Glaucoma is the second leading cause of blindness worldwide, being characterized by progressive optic nerve damage and loss of retinal ganglion cells (RGCs), accompanied by increased inflammatory response involving retinal microglial cells. The etiology of glaucoma is still unknown, and despite elevated intraocular pressure (IOP) being a major risk factor, the exact mechanisms responsible for RGC degeneration remain unknown. Caffeine, which is an antagonist of adenosine receptors, is the most widely consumed psychoactive drug in the world. Several evidences suggest that caffeine can attenuate the neuroinflammatory responses and afford protection upon central nervous system (CNS) injury. We took advantage of a well characterized animal model of glaucoma to investigate whether caffeine administration controls neuroinflammation and elicits neuroprotection. Caffeine or water were administered ad libitum and ocular hypertension (OHT) was induced by laser photocoagulation of the limbal veins in Sprague Dawley rats. Herein, we show that caffeine is able to partially decrease the IOP in ocular hypertensive animals. More importantly, we found that drinking caffeine prevented retinal microglia-mediated neuroinflammatory response and attenuated the loss of RGCs in animals with ocular hypertension (OHT). This study opens the possibility that caffeine or adenosine receptor antagonists might be a therapeutic option to manage RGC loss in glaucoma.

  20. Caffeine administration prevents retinal neuroinflammation and loss of retinal ganglion cells in an animal model of glaucoma

    PubMed Central

    Madeira, Maria H.; Ortin-Martinez, Arturo; Nadal-Nícolas, Francisco; Ambrósio, António F.; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta; Santiago, Ana Raquel

    2016-01-01

    Glaucoma is the second leading cause of blindness worldwide, being characterized by progressive optic nerve damage and loss of retinal ganglion cells (RGCs), accompanied by increased inflammatory response involving retinal microglial cells. The etiology of glaucoma is still unknown, and despite elevated intraocular pressure (IOP) being a major risk factor, the exact mechanisms responsible for RGC degeneration remain unknown. Caffeine, which is an antagonist of adenosine receptors, is the most widely consumed psychoactive drug in the world. Several evidences suggest that caffeine can attenuate the neuroinflammatory responses and afford protection upon central nervous system (CNS) injury. We took advantage of a well characterized animal model of glaucoma to investigate whether caffeine administration controls neuroinflammation and elicits neuroprotection. Caffeine or water were administered ad libitum and ocular hypertension (OHT) was induced by laser photocoagulation of the limbal veins in Sprague Dawley rats. Herein, we show that caffeine is able to partially decrease the IOP in ocular hypertensive animals. More importantly, we found that drinking caffeine prevented retinal microglia-mediated neuroinflammatory response and attenuated the loss of RGCs in animals with ocular hypertension (OHT). This study opens the possibility that caffeine or adenosine receptor antagonists might be a therapeutic option to manage RGC loss in glaucoma. PMID:27270337

  1. Retinal ganglion cell layer of the Caspian seal Pusa caspica: topography and localization of the high-resolution area.

    PubMed

    Mass, Alla M; Supin, A Y

    2010-01-01

    Retinal topography, cell density and sizes of ganglion cells in the Caspian seal (Pusa caspica) were analyzed in retinal whole mounts stained with cresyl-violet. The topographic distribution of ganglion cells displayed an area of high cell density located in the temporal quadrant of the retina and was similar to the area centralis of terrestrial carnivores. It extended nasally, above the optic disk, as a streak of increased cell density. In different whole mounts, the peak cell density in the high-density area ranged from 1,684 to 1,844 cells/mm² (mean 1,773 cells/mm²). The cell density data predict a retinal resolution of around 8.5 cycles/degree in water. A distinctive feature of the Caspian seal's retina is the large size of ganglion cells and the low cell density compared to terrestrial mammals. The ganglion cell diameter ranged from 10 to 58 μm. Cell size histograms featured bimodal patterns with groups of small and large ganglion cells. The large cells appeared similar to α-cells of terrestrial mammals and constituted 7% of the total ganglion cell population.

  2. Retinal Ganglion Cell Topography of Five Species of Ground-Foraging Birds

    PubMed Central

    Dolan, Tracy; Fernández-Juricic, Esteban

    2010-01-01

    Birds that forage on the ground have been studied extensively in relation to behavioral trade-offs between foraging and scanning for predators; however, we know little about the topography of their retinas, which can influence how they gather visual information. We characterized the density of retinal ganglion cells across the retina and estimated visual acuity of four Passeriformes (European starling Sturnus vulgaris, brown-headed cowbird Molothrus ater, house sparrow Passer domesticus, house finch Carpodacus mexicanus) and one Columbiforme (mourning dove Zenaida macroura) that forage on the ground. We used cresyl violet to stain retinal ganglion cells and estimated visual acuity based on cell density and eye size. All species contained a single area centralis, where cell densities were >20,000 cells/mm2. The proportion of the retina that fell in each of five cell density ranges varied between species. European starlings and house finches had the largest area of high cell density, mourning doves had the smallest. The largest proportion of the retina (>35%) of brown-headed cowbird and house sparrow was in the second-lowest cell density range. Considering the 25th percentile of highest cell densities, house finches and European starlings showed the highest cell densities and mourning doves the lowest. Estimated visual acuity increased from house finch, house sparrow, brown-headed cowbird, European starling to mourning dove, and was associated with both retinal area and cell density. Our findings suggest that these ground foragers do not have highly specialized retinas in relation to other types of foragers (e.g. tree foragers), probably because foraging on seeds and insects from the ground is not as visually demanding; however, the studied species showed variability in retinal topography that may be related to foraging techniques, eye size constraints, and size of the area centralis. PMID:20516656

  3. The structure of the terminal arborizations of physiologically identified retinal ganglion cell Y axons in the kitten.

    PubMed Central

    Friedlander, M J; Martin, K A; Vahle-Hinz, C

    1985-01-01

    Retinal ganglion cell (r.g.c.) axons (n = 17) in the optic tract of 4-5 week-old kittens and adult cats (n = 4, this study, n = 27 from other reports) were studied both physiologically and morphologically. Axons were initially classified during extracellular recording with a battery of physiological tests that included Fourier analysis of the response to a sinusoidally counterphased sine-wave grating. Y axons had a significant second harmonic response component (greater than twice the fundamental) present independent of the spatial phase position of the grating. These axons were then recorded from intracellularly and subsequently filled ionophoretically with horseradish peroxidase (HRP). The HRP filled the axons' terminal arborizations in the dorsal lateral geniculate nucleus (l.g.n.). The innervation pattern and and structure of the terminal arborizations of the kitten r.g.c. Y axons were compared to those of the adult. The kitten Y axons innervated the l.g.n. in a pattern similar to that of the adult (individual branches from a single axon always innervated lamina A or A1 and may also have innervated lamina C, the medial interlaminar nucleus (m.i.n.) and/or sent branches that coursed medial to the l.g.n.). Fourteen of seventeen of these Y axons in the kitten innervated either of the A-laminae heavily (greater than 200 terminal boutons per axon). The remaining three r.g.c. Y axons in the kitten had only small arborizations within lamina A (less than fifty terminal boutons per axon) but heavily innervated lamina C. The structure of the terminal boutons on the kitten r.g.c. Y axons was highly variable when compared to axons of adult cats. Some of the boutons were spherical or crenulated as in the adult. Many others had filopodia and growth cone-like terminals with fine extensions. This variable maturation of terminal boutons was seen both between axons and on individual axons. The number of boutons on the kitten r.g.c. Y axons in the A-laminae was significantly less

  4. Differential gene expression profiling of large and small retinal ganglion cells

    PubMed Central

    Ivanov, Dmitry; Dvoriantchikova, Galina; Barakat, David J.; Nathanson, Lubov; Shestopalov, Valery I.

    2014-01-01

    Different sub-populations of retinal ganglion cells (RGCs) vary in their sensitivity to pathological conditions such as retinal ischemia, diabetic retinopathy and glaucoma. Comparative transcriptomic analysis of such groups will likely reveal molecular determinants of differential sensitivity to stress. However, gene expression profiling of primary neuronal sub-populations represent a challenge due to the cellular heterogeneity of retinal tissue. In this manuscript, we report the use of a fluorescent neural tracer to specifically label and selectively isolate RGCs with different soma sizes by fluorescence-activated cell sorting (FACS) for the purpose of differential gene expression profiling. We identified 145 genes that were more active in the large RGCs and 312 genes in the small RGCs. Differential data were validated by quantitative RT-PCR, several corresponding proteins were confirmed by immunohistochemistry. Functional characterization revealed differential activity of genes implicated in synaptic transmission, neurotransmitter secretion, axon guidance, chemotaxis, ion transport and tolerance to stress. An in silico reconstruction of cellular networks suggested that differences in pathway activity between the two sub-populations of RGCs are controlled by networks interconnected by SP-1, Erk2(MAPK1), Egr1, Egr2 and, potentially, regulated via transcription factors C/EBPbeta, HSF1, STAT1- and c-Myc. The results show that FACS-aided purification of retrogradely labeled cells can be effectively utilized for transcriptional profiling of adult retinal neurons. PMID:18640154

  5. Expression and regulated nuclear transport of transducers of regulated CREB 1 in retinal ganglion cells.

    PubMed

    Deng, J; Zhang, X-L; Wang, J-W; Teng, L-L; Ge, J; Takemori, H; Xiong, Z-Q; Zhou, Y

    2009-03-31

    Calcium- and cAMP-dependent activation of CREB and transcription of cAMP-responsive element (CRE)-target genes play critical roles in various physiological and pathological conditions. TORCs (transducers of regulated CREB) represent a new family of conserved CREB coactivators that function as intracellular calcium- and cAMP-sensitive coincidence detectors, controlling the kinetics of CRE-mediated responses and long-term potentiation of synaptic transmission. Here we examined the expression and activity-dependent translocation of TORCs in adult retinal ganglion cells (RGCs), the primary target of acute retinal ischemic injury as well as chronic retinal degenerative diseases. We found that both mRNAs of TORC1 and TORC2, but not TORC3, were enriched in adult rat retina. Comparing with TORC2, TORC1 protein was highly and selectively expressed in RGCs. At resting condition, TORC1 protein was localized in the cytoplasm but not nucleus of RGCs. Activation of N-methyl-D-aspartate (NMDA) receptors by intravitreous injection of NMDA or increase of cAMP signaling by administration of forskolin triggered nuclear accumulation of TORC1. Furthermore, transient retinal ischemic injury resulted in peri-nuclear and nuclear accumulation of TORC1 as well as transcription of BDNF in RGCs. Our results demonstrate that TORC1 is enriched in RGCs and its subcellular location could be regulated by Ca(2+) and cAMP, suggesting that manipulation of TORC1 activity may promote survival of RGCs in some optic disease conditions.

  6. Gene delivery into mouse retinal ganglion cells by in utero electroporation

    PubMed Central

    Garcia-Frigola, Cristina; Carreres, Maria Isabel; Vegar, Celia; Herrera, Eloisa

    2007-01-01

    Background The neural retina is a highly structured tissue of the central nervous system that is formed by seven different cell types that are arranged in layers. Despite much effort, the genetic mechanisms that underlie retinal development are still poorly understood. In recent years, large-scale genomic analyses have identified candidate genes that may play a role in retinal neurogenesis, axon guidance and other key processes during the development of the visual system. Thus, new and rapid techniques are now required to carry out high-throughput analyses of all these candidate genes in mammals. Gene delivery techniques have been described to express exogenous proteins in the retina of newborn mice but these approaches do not efficiently introduce genes into the only retinal cell type that transmits visual information to the brain, the retinal ganglion cells (RGCs). Results Here we show that RGCs can be targeted for gene expression by in utero electroporation of the eye of mouse embryos. Accordingly, using this technique we have monitored the morphology of electroporated RGCs expressing reporter genes at different developmental stages, as well as their projection to higher visual targets. Conclusion Our method to deliver ectopic genes into mouse embryonic retinas enables us to follow the course of the entire retinofugal pathway by visualizing RGC bodies and axons. Thus, this technique will permit to perform functional studies in vivo focusing on neurogenesis, axon guidance, axon projection patterning or neural connectivity in mammals. PMID:17875204

  7. Blockade of pathological retinal ganglion cell hyperactivity improves optogenetically evoked light responses in rd1 mice

    PubMed Central

    Barrett, John M.; Degenaar, Patrick; Sernagor, Evelyne

    2015-01-01

    Retinitis pigmentosa (RP) is a progressive retinal dystrophy that causes visual impairment and eventual blindness. Retinal prostheses are the best currently available vision-restoring treatment for RP, but only restore crude vision. One possible contributing factor to the poor quality of vision achieved with prosthetic devices is the pathological retinal ganglion cell (RGC) hyperactivity that occurs in photoreceptor dystrophic disorders. Gap junction blockade with meclofenamic acid (MFA) was recently shown to diminish RGC hyperactivity and improve the signal-to-noise ratio (SNR) of RGC responses to light flashes and electrical stimulation in the rd10 mouse model of RP. We sought to extend these results to spatiotemporally patterned optogenetic stimulation in the faster-degenerating rd1 model and compare the effectiveness of a number of drugs known to disrupt rd1 hyperactivity. We crossed rd1 mice with a transgenic mouse line expressing the light-sensitive cation channel channelrhodopsin2 (ChR2) in RGCs, allowing them to be stimulated directly using high-intensity blue light. We used 60-channel ITO multielectrode arrays to record ChR2-mediated RGC responses from wholemount, ex-vivo retinas to full-field and patterned stimuli before and after application of MFA, 18-β-glycyrrhetinic acid (18BGA, another gap junction blocker) or flupirtine (Flu, a Kv7 potassium channel opener). All three drugs decreased spontaneous RGC firing, but 18BGA and Flu also decreased the sensitivity of RGCs to optogenetic stimulation. Nevertheless, all three drugs improved the SNR of ChR2-mediated responses. MFA also made it easier to discern motion direction of a moving bar from RGC population responses. Our results support the hypothesis that reduction of pathological RGC spontaneous activity characteristic in retinal degenerative disorders may improve the quality of visual responses in retinal prostheses and they provide insights into how best to achieve this for optogenetic prostheses

  8. Central projections of intrinsically photosensitive retinal ganglion cells in the macaque monkey.

    PubMed

    Hannibal, J; Kankipati, L; Strang, C E; Peterson, B B; Dacey, D; Gamlin, P D

    2014-07-01

    Circadian rhythms generated by the suprachiasmatic nucleus (SCN) are entrained to the environmental light/dark cycle via intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin and the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP). The ipRGCs regulate other nonimage-forming visual functions such as the pupillary light reflex, masking behavior, and light-induced melatonin suppression. To evaluate whether PACAP-immunoreactive retinal projections are useful as a marker for central projection of ipRGCs in the monkey brain, we characterized the occurrence of PACAP in melanopsin-expressing ipRGCs and in the retinal target areas in the brain visualized by the anterograde tracer cholera toxin subunit B (CtB) in combination with PACAP staining. In the retina, PACAP and melanopsin were found to be costored in 99% of melanopsin-expressing cells characterized as inner and outer stratifying melanopsin RGCs. Two macaque monkeys were anesthetized and received a unilateral intravitreal injection of CtB. Bilateral retinal projections containing colocalized CtB and PACAP immunostaining were identified in the SCN, the lateral geniculate complex including the pregeniculate nucleus, the pretectal olivary nucleus, the nucleus of the optic tract, the brachium of the superior colliculus, and the superior colliculus. In conclusion, PACAP-immunoreactive projections with colocalized CtB represent retinal projections of ipRGCs in the macaque monkey, supporting previous retrograde tracer studies demonstrating that melanopsin-containing retinal projections reach areas in the primate brain involved in both image- and nonimage-forming visual processing.

  9. Muscarinic acetylcholine receptor-mediated stimulation of retinal ganglion cell photoreceptors.

    PubMed

    Sodhi, Puneet; Hartwick, Andrew T E

    2016-09-01

    Melanopsin-dependent phototransduction in intrinsically photosensitive retinal ganglion cells (ipRGCs) involves a Gq-coupled phospholipase C (PLC) signaling cascade. Acetylcholine, released in the mammalian retina by starburst amacrine cells, can also activate Gq-PLC pathways through certain muscarinic acetylcholine receptors (mAChRs). Using multielectrode array recordings of rat retinas, we demonstrate that robust spiking responses can be evoked in neonatal and adult ipRGCs after bath application of the muscarinic agonist carbachol. The stimulatory action of carbachol on ipRGCs was a direct effect, as confirmed through calcium imaging experiments on isolated ipRGCs in purified cultures. Using flickering (6 Hz) yellow light stimuli at irradiances below the threshold for melanopsin activation, spiking responses could be elicited in ipRGCs that were suppressed by mAChR antagonism. Therefore, this work identified a novel melanopsin-independent pathway for stimulating sustained spiking in ganglion cell photoreceptors. This mAChR-mediated pathway could enhance ipRGC spiking responses in conditions known to evoke retinal acetylcholine release, such as those involving flickering or moving visual stimuli. Furthermore, this work identifies a pharmacological approach for light-independent ipRGC stimulation that could be targeted by mAChR agonists.

  10. THE INJURY RESISTANT ABILITY OF MELANOPSIN-EXPRESSING INTRINSICALLY PHOTOSENSITIVE RETINAL GANGLION CELLS

    PubMed Central

    Cui, Q.; Ren, C.; Sollars, P. J.; Pickard, G. E.; So, K.-F.

    2015-01-01

    Neurons in the mammalian retina expressing the photopigment melanopsin have been identified as a class of intrinsically photosensitive retinal ganglion cells (ipRGCs). This discovery more than a decade ago has opened up an exciting new field of retinal research, and following the initial identification of photosensitive ganglion cells, several subtypes have been described. A number of studies have shown that ipRGCs subserve photoentrainment of circadian rhythms. They also influence other non-image forming functions of the visual system, such as the pupillary light reflex, sleep, cognition, mood, light aversion and development of the retina. These novel photosensitive neurons also influence form vision by contributing to contrast detection. Furthermore, studies have shown that ipRGCs are more injury-resistant following optic nerve injury, in animal models of glaucoma, and in patients with mitochondrial optic neuropathies, i.e., Leber’s hereditary optic neuropathy and dominant optic atrophy. There is also an indication that these cells may be resistant to glutamate-induced excitotoxicity. Herein we provide an overview of ipRGCs and discuss the injury-resistant character of these neurons under certain pathological and experimental conditions. PMID:25446359

  11. Edible wild vegetable, Gymnaster koraiensis protects retinal ganglion cells against oxidative stress.

    PubMed

    Kim, Kyung-A; Kang, Kui Dong; Lee, Eun Ha; Nho, Chu Won; Jung, Sang Hoon

    2011-09-01

    This study was conducted to determine whether Gymnaster koraiensis is effective at blunting the negative influence of N-methyl-D-aspartate (NMDA) on the retinas of rats and on oxidative stress induced cell death in transformed retinal ganglion cells (RGC-5). The ethyl acetate fraction of G. koraiensis (EAGK) and the isolated compound, 3,5-di-O-caffeoylquinic acid (3,5-DCQA), were shown to significantly attenuate the negative effect of H(2)O(2) on the RGC-5 cells tested by various procedures. The inclusion of EAGK or 3,5-DCQA in the culture reduced the reactive oxygen species (ROS) and replenished the reduced glutathione levels caused by various radical species such as H(2)O(2,) O(2)()(-) or ()OH. Moreover, EAGK or 3,5-DCQA inhibited lipid peroxidation caused by sodium nitroprusside (SNP) in rat brain homogenates. From in vivo experiments, the presence of NMDA in the retina affected the thickness of the inner plexiform layer (IPL) and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) in positive ganglion cells. EAGK or 3,5-DCQA protected the thinning of the IPL and increased TUNEL positive cells in the ganglion cell layer (GCL). Our results clearly demonstrate the neuroprotective effect of EAGK both in vitro and in vivo. Moreover, 3,5-DCQA is suggested to be the active compound of EAGK. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Transcriptome of Atoh7 retinal progenitor cells identifies new Atoh7-dependent regulatory genes for retinal ganglion cell formation.

    PubMed

    Gao, Zhiguang; Mao, Chai-An; Pan, Ping; Mu, Xiuqian; Klein, William H

    2014-11-01

    The bHLH transcription factor ATOH7 (Math5) is essential for establishing retinal ganglion cell (RGC) fate. However, Atoh7-expressing retinal progenitor cells (RPCs) can give rise to all retinal cell types, suggesting that other factors are involved in specifying RGCs. The basis by which a subpopulation of Atoh7-expressing RPCs commits to an RGC fate remains uncertain but is of critical importance to retinal development since RGCs are the earliest cell type to differentiate. To better understand the regulatory mechanisms leading to cell-fate specification, a binary genetic system was generated to specifically label Atoh7-expressing cells with green fluorescent protein (GFP). Fluorescence-activated cell sorting (FACS)-purified GFP(+) and GFP(-) cells were profiled by RNA-seq. Here, we identify 1497 transcripts that were differentially expressed between the two RPC populations. Pathway analysis revealed diminished growth factor signaling in Atoh7-expressing RPCs, indicating that these cells had exited the cell cycle. In contrast, axon guidance signals were enriched, suggesting that axons of Atoh7-expressing RPCs were already making synaptic connections. Notably, many genes enriched in Atoh7-expressing RPCs encoded transcriptional regulators, and several were direct targets of ATOH7, including, and unexpectedly, Ebf3 and Eya2. We present evidence for a Pax6-Atoh7-Eya2 pathway that acts downstream of Atoh7 but upstream of differentiation factor Pou4f2. EYA2 is a protein phosphatase involved in protein-protein interactions and posttranslational regulation. These properties, along with Eya2 as an early target gene of ATOH7, suggest that EYA2 functions in RGC specification. Our results expand current knowledge of the regulatory networks operating in Atoh7-expressing RPCs and offer new directions for exploring the earliest aspects of retinogenesis. © 2014 Wiley Periodicals, Inc.

  13. A retinal ganglion cell that can signal irradiance continuously for 10 hours.

    PubMed

    Wong, Kwoon Y

    2012-08-15

    A recently discovered type of mammalian retinal ganglion cell encodes environmental light intensity and mediates non-image-forming visual behaviors, such as the pupillary reflex and circadian photoentrainment. These intrinsically photosensitive retinal ganglion cells (ipRGCs) generate endogenous, melanopsin-based photoresponses as well as extrinsic, rod/cone-driven responses. Because the ipRGCs' light responses and the behaviors they control are both remarkably tonic, these cells have been hypothesized to be capable of irradiance detection lasting throughout the day. I tested this hypothesis by obtaining multielectrode-array recordings from ipRGCs in a novel rat eyecup preparation that enhances the regeneration of rod/cone photopigments. I found that 10 h constant light could continuously evoke action potentials in these ganglion cells under conditions that stimulated (1) only melanopsin, (2) mainly the rod input, and (3) both intrinsic and extrinsic responses. In response to a 10 h stimulus with gradual intensity changes to simulate sunrise and sunset, ipRGC firing rates slowly increased during the "sunrise" phase and slowly decreased during the "sunset" phase. Furthermore, I recorded from putative ipRGCs of melanopsin-knock-out mice and found that these cells retained the ability to respond in a sustained fashion to 20 min light steps, indicating that melanopsin is not required for such tonic responses. In conclusion, ipRGCs can signal light continuously for at least 10 h and can probably track gradual irradiance changes over the course of the day. These results further suggest that the photoreceptors and ON bipolar cells presynaptic to ipRGCs may be able to respond to light continuously for 10 h.

  14. Distribution of mesencephalic nucleus and trigeminal ganglion mechanoreceptors in the periodontal ligament of the cat.

    PubMed Central

    Linden, R W; Scott, B J

    1989-01-01

    1. In anaesthetized cats recordings have been made in the mesencephalic nucleus of the fifth cranial nerve and the trigeminal ganglion from neurones that respond when forces are applied to the mandibular canine tooth. The site of the mechanoreceptors in the periodontal ligament and their distribution around the tooth root have been determined. 2. Receptors with their cell bodies in the mesencephalic nucleus were found to be situated in the periodontal ligament in a discrete area intermediate between the fulcrum and apex of the tooth, while those in the trigeminal ganglion were situated in the whole area of the periodontal ligament between the fulcrum and apex of the tooth. 3. All of the located mechanoreceptors responded maximally when that part of the ligament in which they lay was put under tension. 4. The directional sensitivities of the mechanoreceptors suggested that there was an uneven distribution around the tooth root of receptors with cell bodies in the mesencephalic nucleus. In contrast mechanoreceptors with cell bodies in the trigeminal ganglion were distributed more equally around the tooth root. The rationale for the differences requires further investigation. PMID:2795482

  15. The course of post-ganglionic sympathetic fibres distributed with the trigeminal nerve in the cat.

    PubMed Central

    Matthews, B; Robinson, P P

    1980-01-01

    1. The course of post-ganglionic sympathetic fibres to the jaws, face and eye was investigated in cats by observing the effects of nerve sections on responses evoked by stimulation of the cervical sympathetic trunk. 2. Sympathetic fibres were present in the infraorbital and inferior alveolar nerves. From the superior cervical ganglion, all of these fibres travelled in the internal carotid nerve and all but a few passed through the foramen lacerum and joined the trigeminal nerve at its ganglion. 3. Compound action potentials were recorded from sympathetic fibres in six out of twenty-seven teeth. These fibres followed the route described above. 4. Sympathetic fibres to the pupil and levator palpebrae superioris passed from the internal carotid nerve to the eye via the foramen lacerum and the superior orbital fissure. Some fibres causing piloerection in front of the ear travelled by the same route and some travelled with the maxillary division of the trigeminal nerve. 5. Sympathetic fibres to the nictitating membrane followed a similar route to those supplying the pupil except that they entered the cranial vault through the pterygoid foramen. 6. The secretomotor fibres to the submandibular salivary gland and some vasoconstrictor fibres to the lip did not travel with the internal carotid nerve or major branches of the trigeminal nerve. PMID:7431241

  16. Retinal Arterial Occlusive Disease in a Young Patient with Cat Scratch Disease

    PubMed Central

    Batsos, Georgios; Kabanarou, Stamatina A.; Fotiou, Pantelis; Rouvas, Alexandros; Xirou, Tina

    2013-01-01

    Purpose To report an unusual case of a branch retinal arterial occlusion and bilateral multifocal retinitis in a young woman with cat scratch disease. Methods A 23-year-old woman was referred to our clinic complaining of a sudden scotoma in the upper part of the visual field of her left eye. Fundoscopy revealed occlusion of an inferior temporal branch of the retinal artery in the left eye and bilateral multifocal retinitis, which was confirmed by fluorescein angiography. Subsequent indocyanine angiography did not reveal choroidal involvement. Laboratory analysis showed rising IgG titers for Bartonella henselae. Results Cat scratch disease was diagnosed, and a 4-week course of doxycycline was initiated. The patient responded well to the antibiotics. Both retinitis and arterial occlusion were resolved, the visual field was regained and the patient reported elimination of her symptoms. Conclusions Cat scratch disease should be considered in the differential diagnosis in young patients with retinal occlusive disease. PMID:24019792

  17. Retinal arterial occlusive disease in a young patient with cat scratch disease.

    PubMed

    Batsos, Georgios; Kabanarou, Stamatina A; Fotiou, Pantelis; Rouvas, Alexandros; Xirou, Tina

    2013-01-01

    To report an unusual case of a branch retinal arterial occlusion and bilateral multifocal retinitis in a young woman with cat scratch disease. A 23-year-old woman was referred to our clinic complaining of a sudden scotoma in the upper part of the visual field of her left eye. Fundoscopy revealed occlusion of an inferior temporal branch of the retinal artery in the left eye and bilateral multifocal retinitis, which was confirmed by fluorescein angiography. Subsequent indocyanine angiography did not reveal choroidal involvement. Laboratory analysis showed rising IgG titers for Bartonella henselae. Cat scratch disease was diagnosed, and a 4-week course of doxycycline was initiated. The patient responded well to the antibiotics. Both retinitis and arterial occlusion were resolved, the visual field was regained and the patient reported elimination of her symptoms. Cat scratch disease should be considered in the differential diagnosis in young patients with retinal occlusive disease.

  18. Morphological diversity of displaced retinal ganglion cells in the rat: a lucifer yellow study.

    PubMed

    Buhl, E H; Dann, J F

    1988-03-08

    Displaced retinal ganglion cells (DRGCs) were retrogradely labelled by injections of the fluorescent dye Fast Blue into the superior colliculi of pigmented rats. Following fixation these cells were intracellularly injected with Lucifer Yellow to determine their dendritic morphology and distribution. Graphic reconstruction of Lucifer Yellow-filled prelabelled neurones revealed a heterogeneous population of DRGCs. Their stratification within the inner plexiform layer was diverse and cells were classified according to their dendritic morphology. The present sample consists largely of unistratifying neurones, the dendrites of which arborized within a narrow sublamina of the inner plexiform layer. They were characterized by a centrally located soma and densely branched dendritic network with little overlap within the branching pattern. In contrast, bistratifying DRGCs possessed a loose and sparsely branched dendritic structure, while diffusely stratifying neurones contained a high degree of dendritic crossing, culminating in a complex network, in which the soma position was biased toward the periphery. One type of DRGC bore a striking resemblance to type 1 neurones (Perry, 1979; Proc. R. Soc. Lond. [Biol.] 204:363-375) in the ganglion cell layer. They were characterized by a large soma (15.5 micron +/- 2.2 micron s.d.) and a dendritic field diameter averaging 288 micron (s.d. +/- 62 micron) and were on average larger than the rest of the displaced population but smaller than type 1 cells in the ganglion cell layer. Since the stratification patterns of the displaced and nondisplaced type 1 neurones were indistinguishable, it is reasonable to assume that the Lucifer Yellow-filled cells in the present study represent the displaced counterpart of regular type 1 ganglion cells.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Estimation of Retinal Ganglion Cell Loss in Glaucomatous Eyes With a Relative Afferent Pupillary Defect

    PubMed Central

    Tatham, Andrew J.; Meira-Freitas, Daniel; Weinreb, Robert N.; Marvasti, Amir H.; Zangwill, Linda M.; Medeiros, Felipe A.

    2014-01-01

    Purpose. To estimate retinal ganglion cell (RGC) losses associated with a relative afferent pupillary defect (RAPD) in glaucoma. Methods. A cross-sectional study was conducted including both eyes of 103 participants from the Diagnostic Innovations in Glaucoma Study. A total of 77 subjects had glaucoma in at least one eye and 26 were healthy. Pupil responses were assessed using an automated pupillometer that records the magnitude of RAPD as an “RAPD score.” Standard automated perimetry (SAP) and optical coherence tomography (OCT) also were performed. Retinal ganglion cell counts were estimated using empirical formulas that combine estimates from SAP and OCT. The estimated percentage RGC loss was calculated using the combined structure function index (CSFI). Results. There was good correlation between RAPD magnitude and intereye differences in estimated RGCs (R2 = 0.492, P < 0.001), mean deviation (R2 = 0.546, P < 0.001), retinal nerve fiber layer thickness (R2 = 0.362, P < 0.001), and CSFI (R2 = 0.484, P < 0.001). Therefore, a high RAPD score is likely to indicate large asymmetric RGC losses. The relationship between intereye difference in RGC counts and RAPD score was described best by the formula; RGC difference = 21,896 + 353,272 * RAPD score. No healthy subjects had an absolute RAPD score > 0.3, which was associated with asymmetry of 105,982 cells (or 12%). Conclusions. Good correlation between the magnitude of RAPD and intereye differences in mean deviation and estimated RGC counts suggests pupillometry may be useful for quantifying asymmetric damage in glaucoma. (ClinicalTrials.gov number, NCT00221897.) PMID:24282221

  20. Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.

    PubMed

    Lampert, E J; Andorra, M; Torres-Torres, R; Ortiz-Pérez, S; Llufriu, S; Sepúlveda, M; Sola, N; Saiz, A; Sánchez-Dalmau, B; Villoslada, P; Martínez-Lapiscina, Elena H

    2015-11-01

    Multiple Sclerosis (MS) results in color vision impairment regardless of optic neuritis (ON). The exact location of injury remains undefined. The objective of this study is to identify the region leading to dyschromatopsia in MS patients' NON-eyes. We evaluated Spearman correlations between color vision and measures of different regions in the afferent visual pathway in 106 MS patients. Regions with significant correlations were included in logistic regression models to assess their independent role in dyschromatopsia. We evaluated color vision with Hardy-Rand-Rittler plates and retinal damage using Optical Coherence Tomography. We ran SIENAX to measure Normalized Brain Parenchymal Volume (NBPV), FIRST for thalamus volume and Freesurfer for visual cortex areas. We found moderate, significant correlations between color vision and macular retinal nerve fiber layer (rho = 0.289, p = 0.003), ganglion cell complex (GCC = GCIP) (rho = 0.353, p < 0.001), thalamus (rho = 0.361, p < 0.001), and lesion volume within the optic radiations (rho = -0.230, p = 0.030). Only GCC thickness remained significant (p = 0.023) in the logistic regression model. In the final model including lesion load and NBPV as markers of diffuse neuroaxonal damage, GCC remained associated with dyschromatopsia [OR = 0.88 95 % CI (0.80-0.97) p = 0.016]. This association remained significant when we also added sex, age, and disease duration as covariates in the regression model. Dyschromatopsia in NON-eyes is due to damage of retinal ganglion cells (RGC) in MS. Color vision can serve as a marker of RGC damage in MS.

  1. Epigenetic intervention with a BET inhibitor ameliorates acute retinal ganglion cell death in mice

    PubMed Central

    Li, Jun; Zhao, Lei; Urabe, Go; Fu, Yingmei

    2017-01-01

    Purpose The bromo and extraterminal (BET) epigenetic “reader” family is becoming an appealing new therapeutic target for several common diseases, yet little is known of its role in retinal neurodegeneration. We explored the potential of BET inhibition in the protection of retinal ganglion cells (RGCs). Methods To test the therapeutic effect of JQ1, an inhibitor highly selective for the BET family of proteins, we used an acute RGC damage model induced by N-methyl-D-aspartic acid (NMDA) excitotoxicity. Adult C57BL/6 mice received an intravitreal injection of NMDA with (or without) JQ1 in one eye and vehicle control in the contralateral eye; RGC loss was assessed on retinal sections and whole mounts. Gene expression and apoptosis were analyzed by quantitative real time (RT)-PCR and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), respectively. For counting RGCs, immunostaining of the marker protein BRN3A was performed on whole mounts. Results NMDA treatment eliminated RGCs (day 7 and day 14 post injection) and diminished the expression (mRNAs) of RGC-selective genes, including Thy1, Nrn1, Sncg, and Nfl (day 3 and day 7). In contrast, co-injection with JQ1 maintained the number and gene expression of RGCs at ~2 fold of the control (NMDA only, no JQ1), and it decreased NMDA-induced TUNEL-positive cells in the RGC layer by 35%. While NMDA treatment dramatically upregulated mRNAs of inflammatory cytokines (TNFα, IL-1β, MCP-1, RANTES) in retinal homogenates, co-injection with JQ1 suppressed their upregulation by ~50%. Conclusions Intravitreal injection of a BET inhibitor (JQ1) ameliorates NMDA-induced RGC death, revealing the RGC-protective potential of pharmacological blockage of the BET family. This new strategy of epigenetic intervention may be extended to other retinal degenerative conditions. PMID:28356707

  2. Stage-specific differentiation of iPSCs toward retinal ganglion cell lineage

    PubMed Central

    Deng, Fei; Chen, Mengfei; Liu, Ying; Hu, Huiling; Xiong, Yunfan; Xu, Chaochao; Liu, Yuchun; Li, Kangjun; Zhuang, Jing

    2016-01-01

    Purpose As an alternative and desirable approach for regenerative medicine, human induced pluripotent stem cell (hiPSC) technology raises the possibility of developing patient-tailored cell therapies to treat intractable degenerative diseases in the future. This study was undertaken to guide human Tenon’s capsule fibroblasts-derived iPSCs (TiPSCs) to differentiate along the retinal ganglion cell (RGC) lineage, aiming at producing appropriate cellular material for RGC regeneration. Methods By mimicking RGC genesis, we deliberately administered the whole differentiation process and directed the stage-specific differentiation of human TiPSCs toward an RGC fate via manipulation of the retinal inducers (DKK1+Noggin+Lefty A) alongside master gene (Atoh7) sequentially. Throughout this stepwise differentiation process, changes in primitive neuroectodermal, eye field, and RGC marker expression were monitored with quantitative real-time PCR (qRT-PCR), immunocytochemistry, and/or flow cytometry. Results Upon retinal differentiation, a large fraction of the cells developed characteristics of retinal progenitor cells (RPCs) in response to simulated environment signaling (DKK1+Noggin+Lefty A), which was selectively recovered with manual isolation approaches and then maintained in the presence of mitogen for multiple passages. Thereafter, overexpression of ATOH7 further promoted RGC specification in TiPSC-derived RPCs. A subset of transfected cells displayed RGC-specific expression patterns, including Brn3b, iSlet1, calretinin, and Tuj, and approximately 23% of Brn3b-positive RGC-like cells were obtained finally. Conclusions Our DKK1+Noggin+Lefty A/Atoh7-based RGC-induction regime could efficiently direct TiPSCs to differentiate along RGC lineage in a stage-specific manner, which may provide a benefit to develop possible cell therapies to treat retinal degenerative diseases such as glaucoma. PMID:27293372

  3. Human organotypic retinal cultures (HORCs) as a chronic experimental model for investigation of retinal ganglion cell degeneration.

    PubMed

    Osborne, Andrew; Hopes, Marina; Wright, Phillip; Broadway, David C; Sanderson, Julie

    2016-02-01

    There is a growing need for models of human diseases that utilise native, donated human tissue in order to model disease processes and develop novel therapeutic strategies. In this paper we assessed the suitability of adult human retinal explants as a potential model of chronic retinal ganglion cell (RGC) degeneration. Our results confirmed that RGC markers commonly used in rodent studies (NeuN, βIII Tubulin and Thy-1) were appropriate for labelling human RGCs and followed the expected differential expression patterns across, as well as throughout, the macular and para-macular regions of the retina. Furthermore, we showed that neither donor age nor post-mortem time (within 24 h) significantly affected the initial expression levels of RGC markers. In addition, the feasibility of using human post mortem donor tissue as a long-term model of RGC degeneration was determined with RGC protein being detectable up to 4 weeks in culture with an associated decline in RGC mRNA and significant, progressive, apoptotic labelling of NeuN(+) cells. Differences in RGC apoptosis might have been influenced by medium compositions indicating that media constituents could play a role in supporting axotomised RGCs. We propose that using ex vivo human explants may prove to be a useful model for testing the effectiveness of neuroprotective strategies.

  4. The ciliary margin zone of the mammalian retina generates retinal ganglion cells

    PubMed Central

    Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol

    2016-01-01

    Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

  5. Pan-retinal characterisation of Light Responses from Ganglion Cells in the Developing Mouse Retina

    PubMed Central

    Hilgen, Gerrit; Pirmoradian, Sahar; Pamplona, Daniela; Kornprobst, Pierre; Cessac, Bruno; Hennig, Matthias H.; Sernagor, Evelyne

    2017-01-01

    We have investigated the ontogeny of light-driven responses in mouse retinal ganglion cells (RGCs). Using a large-scale, high-density multielectrode array, we recorded from hundreds to thousands of RGCs simultaneously at pan-retinal level, including dorsal and ventral locations. Responses to different contrasts not only revealed a complex developmental profile for ON, OFF and ON-OFF responses, but also unveiled differences between dorsal and ventral RGC responses. At eye-opening, dorsal RGCs of all types were more responsive to light, perhaps indicating an environmental priority to nest viewing for pre-weaning pups. The developmental profile of ON and OFF responses exhibited antagonistic behaviour, with the strongest ON responses shortly after eye-opening, followed by an increase in the strength of OFF responses later on. Further, we found that with maturation receptive field (RF) center sizes decrease, spike-triggered averaged responses to white noise become stronger, and centers become more circular while maintaining differences between RGC types. We conclude that the maturation of retinal functionality is not spatially homogeneous, likely reflecting ecological requirements that favour earlier maturation of the dorsal retina. PMID:28186129

  6. Methylprednisolone fails to preserve retinal ganglion cells and visual function after ocular ischemia in rats.

    PubMed

    Dimitriu, Cornelia; Bach, Michael; Lagrèze, Wolf A; Jehle, Thomas

    2008-11-01

    Methylprednisolone (MP) is commonly used to treat traumatic optic neuropathy and optic neuritis, but its benefit in terms of neuronal survival remains controversial. The aim of this study was to investigate the effects of MP on retinal ganglion cell (RGC) survival and visual function after ischemia in rats. Ocular ischemia was induced by elevated intraocular pressure. Rats were treated with NaCl, 1 mg/kg/d, or 30 mg/kg/d intraperitoneal MP over 3 days. RGCs were labeled retrogradely 4 days after ischemia and were quantified 6 days later. Post-ischemic retinal function was assessed by scotopic and photopic electroretinography (ERG). Optic nerve function was investigated on days 4 and 10 after ischemia by visual evoked potentials (VEPs). Compared with nonischemic eyes, ischemia reduced RGCs with NaCl to 47% +/- 3% (mean +/- SEM) and to 46% +/- 3% and 43% +/- 6% with 1 mg/kg/d and 30 mg/kg/d MP. ERG did not differ significantly for any parameter among the three groups. Four days after ischemia, the VEPs of rats receiving any dose of MP were significantly higher than the control. VEPs in both steroid groups fell to control levels 10 days after ischemia. Treatment with MP did not improve RGC survival or retinal function. The VEP showed a short-term benefit because of steroids.

  7. Decoding of retinal ganglion cell spike trains evoked by temporally patterned electrical stimulation.

    PubMed

    Ryu, Sang Baek; Ye, Jang Hee; Goo, Yong Sook; Kim, Chi Hyun; Kim, Kyung Hwan

    2010-08-12

    For successful restoration of vision by retinal prostheses, the neural activity of retinal ganglion cells (RGCs) evoked by electrical stimulation should represent the information of spatiotemporal patterns of visual input. We propose a method to evaluate the effectiveness of stimulation pulse trains so that the crucial temporal information of a visual input is accurately represented in the RGC responses as the amplitudes of pulse trains are modulated according to the light intensity. This was enabled by spike train decoding. The effectiveness of the stimulation was evaluated by the accuracy of decoding pulse amplitude from the RGC spike train, i.e., by the similarity between the original and the decoded pulse amplitude time series. When the parameters of stimulation were suitably determined, the RGC responses were reliably modulated by varying the amplitude of electrical pulses. Accordingly, the temporal pattern of pulse amplitudes could be successfully decoded from multiunit RGC spike trains. The range of pulse amplitude and the pulse rate were critical for accurate representation of input information in RGC responses. These results suggest that pulse amplitude modulation is a feasible means to encode temporal visual information by RGC spike trains and thus to implement stimulus encoding strategies for retinal prostheses.

  8. Longitudinal In Vivo Imaging of Retinal Ganglion Cells and Retinal Thickness Changes Following Optic Nerve Injury in Mice

    PubMed Central

    Chauhan, Balwantray C.; Stevens, Kelly T.; Levesque, Julie M.; Nuschke, Andrea C.; Sharpe, Glen P.; O'Leary, Neil; Archibald, Michele L.; Wang, Xu

    2012-01-01

    Background Retinal ganglion cells (RGCs) die in sight-threatening eye diseases. Imaging RGCs in humans is not currently possible and proof of principle in experimental models is fundamental for future development. Our objective was to quantify RGC density and retinal thickness following optic nerve transection in transgenic mice expressing cyan fluorescent protein (CFP) under control of the Thy1 promoter, expressed by RGCs and other neurons. Methodology/Principal Findings A modified confocal scanning laser ophthalmoscopy (CSLO)/spectral-domain optical coherence tomography (SD-OCT) camera was used to image and quantify CFP+ cells in mice from the B6.Cg-Tg(Thy1-CFP)23Jrs/J line. SD-OCT circle (1 B-scan), raster (37 B-scans) and radial (24 B-scans) scans of the retina were also obtained. CSLO was performed at baseline (n = 11) and 3 (n = 11), 5 (n = 4), 7 (n = 10), 10 (n = 6), 14 (n = 7) and 21 (n = 5) days post-transection, while SD-OCT was performed at baseline and 7, 14 and 35 days (n = 9) post-transection. Longitudinal change in CFP+ cell density and retinal thickness were computed. Compared to baseline, the mean (SD) percentage CFP+ cells remaining at 3, 5, 7, 10, 14 and 21 days post-transection was 86 (9)%, 63 (11)%, 45 (11)%, 31 (9)%, 20 (9)% and 8 (4)%, respectively. Compared to baseline, the mean (SD) retinal thickness at 7 days post-transection was 97 (3)%, 98 (2)% and 97 (4)% for the circle, raster and radial scans, respectively. The corresponding figures at 14 and 35 days post-transection were 96 (3)%, 97 (2)% and 95 (3)%; and 93 (3)%, 94 (3)% and 92 (3)%. Conclusions/Significance Longitudinal imaging showed an exponential decline in CFP+ cell density and a small (≤8%) reduction in SD-OCT measured retinal thickness post-transection. SD-OCT is a promising tool for detecting structural changes in experimental optic neuropathy. These results represent an important step towards translation for clinical use. PMID:22768284

  9. A method for electrophysiological characterization of hamster retinal ganglion cells using a high-density CMOS microelectrode array

    PubMed Central

    Jones, Ian L.; Russell, Thomas L.; Farrow, Karl; Fiscella, Michele; Franke, Felix; Müller, Jan; Jäckel, David; Hierlemann, Andreas

    2015-01-01

    Knowledge of neuronal cell types in the mammalian retina is important for the understanding of human retinal disease and the advancement of sight-restoring technology, such as retinal prosthetic devices. A somewhat less utilized animal model for retinal research is the hamster, which has a visual system that is characterized by an area centralis and a wide visual field with a broad binocular component. The hamster retina is optimally suited for recording on the microelectrode array (MEA), because it intrinsically lies flat on the MEA surface and yields robust, large-amplitude signals. However, information in the literature about hamster retinal ganglion cell functional types is scarce. The goal of our work is to develop a method featuring a high-density (HD) complementary metal-oxide-semiconductor (CMOS) MEA technology along with a sequence of standardized visual stimuli in order to categorize ganglion cells in isolated Syrian Hamster (Mesocricetus auratus) retina. Since the HD-MEA is capable of recording at a higher spatial resolution than most MEA systems (17.5 μm electrode pitch), we were able to record from a large proportion of RGCs within a selected region. Secondly, we chose our stimuli so that they could be run during the experiment without intervention or computation steps. The visual stimulus set was designed to activate the receptive fields of most ganglion cells in parallel and to incorporate various visual features to which different cell types respond uniquely. Based on the ganglion cell responses, basic cell properties were determined: direction selectivity, speed tuning, width tuning, transience, and latency. These properties were clustered to identify ganglion cell types in the hamster retina. Ultimately, we recorded up to a cell density of 2780 cells/mm2 at 2 mm (42°) from the optic nerve head. Using five parameters extracted from the responses to visual stimuli, we obtained seven ganglion cell types. PMID:26528115

  10. Topographic specializations in the retinal ganglion cell layer correlate with lateralized visual behavior, ecology, and evolution in cockatoos.

    PubMed

    Coimbra, João Paulo; Collin, Shaun P; Hart, Nathan S

    2014-10-15

    Cockatoos are a unique avian group inhabiting a diversity of arboreal and terrestrial microhabitats. Most species display strong lateralized visual behaviors using their left eye/foot to assist with food manipulation during foraging. In this study, we used retinal wholemounts and stereological methods to investigate whether the topographic distribution of retinal ganglion cells in cockatoos reflects their lateralized behaviors and microhabitat diversity. We found that all species studied possess a horizontal visual streak and a shallow central fovea that afford increased spatial resolution in the lateral visual field. Arboreal cockatoos have a well-defined dorsotemporal area, in contrast to terrestrial cockatoos, in which this specialization is inconspicuous or absent. Terrestrial cockatoos also have a triangular extension of increased ganglion cell density directed toward the dorsotemporal retinal periphery. Both the dorsotemporal area and the triangular extension enhance spatial resolution in the frontal and inferior visual fields, which potentially assists with binocular coordination during foraging. We found significantly higher ganglion cell densities in the left (52,000-72,000 cells/mm2) compared with the right (42,500-50,000 cells/mm2) perifoveal region of species that have strong left eye-left foot lateralized behaviors. In contrast, cockatoo species that show no lateralized behaviors have equivalent retinal ganglion cell densities in both left and right perifoveal regions (42,500-52,500 cells/mm2). Retinal ganglion cell peak densities in the dorsotemporal area showed no significant difference between left and right eyes for any species, suggesting that cockatoos use both eyes to extract information in the binocular visual field, independent of the degree of lateralization.

  11. A Thy1-CFP DBA/2J mouse line with cyan fluorescent protein expression in retinal ganglion cells

    PubMed Central

    RAYMOND, IONA D.; POOL, ANGELA L.; VILA, ALEJANDRO; BRECHA, NICHOLAS C.

    2013-01-01

    A DBA/2J (D2) transgenic mouse line with cyan fluorescent protein (CFP) reporter expression in ganglion cells was developed for the analysis of ganglion cells during progressive glaucoma. The Thy1-CFP D2 (CFP-D2) line was created by congenically breeding the D2 line, which develops pigmentary glaucoma, and the Thy1-CFP line, which expresses CFP in ganglion cells. Microsatellite marker analysis of CFP-D2 progeny verified the genetic inclusion of the D2 isa and ipd loci. Specific mutations within these loci lead to dysfunctional melanosomal proteins and glaucomatous phenotype in D2 mice. Polymerase chain reaction analysis confirmed the inclusion of the Thy1-CFP transgene. CFP-fluorescent ganglion cells, 6–20 μm in diameter, were distributed in all retinal regions, CFP processes were throughout the inner plexiform layer, and CFP-fluorescent axons were in the fiber layer and optic nerve head. Immunohistochemistry with antibodies to ganglion cell markers NF-L, NeuN, Brn3a, and SMI32 was used to confirm CFP expression in ganglion cells. Immunohistochemistry with antibodies to amacrine cell markers HPC-1 and ChAT was used to confirm weak CFP expression in cholinergic amacrine cells. CFP-D2 mice developed a glaucomatous phenotype, including iris disease, ganglion cell loss, attrition of the fiber layer, and elevated intraocular pressure. A CFP-D2 transgenic line with CFP-expressing ganglion cells was developed, which has (1) a predominantly D2 genetic background, (2) CFP-expressing ganglion cells, and (3) age-related progressive glaucoma. This line will be of value for experimental studies investigating ganglion cells and their axons in vivo and in vitro during the progressive development of glaucoma. PMID:19930759

  12. Role of C/EBP Homologous Protein in Retinal Ganglion Cell Death After Ischemia/Reperfusion Injury

    PubMed Central

    Nashine, Sonali; Liu, Yang; Kim, Byung-Jin; Clark, Abbot F.; Pang, Iok-Hou

    2015-01-01

    Purpose. To investigate the role of C/EBP homologous protein (CHOP), a proapoptotic protein, and the unfolded protein response (UPR) marker that is involved in endoplasmic reticulum (ER) stress-mediated apoptosis in mouse retinal ganglion cell (RGC) death following ischemia/reperfusion (I/R) injury. Methods. Retinal I/R injury was induced in adult C57BL/6J wild-type (WT) and CHOP knockout (Chop−/−) mice by raising IOP to 120 mm Hg for 60 minutes. Expression of CHOP and other UPR markers was studied by Western blot and immunohistochemistry. Retinal ganglion cell counts were performed in retinal flat mounts stained with an RGC marker. Retinal ganglion cell function was evaluated by scotopic threshold response (STR) electroretinography. Results. In WT mice, retinal CHOP was upregulated by 30% in I/R-injured eyes compared to uninjured eyes 3 days after injury (P < 0.05). Immunohistochemistry confirmed CHOP upregulation specifically in RGCs. CHOP knockout did not affect baseline RGC density or STR amplitude. Ischemia/reperfusion injury decreased RGC densities and STR amplitudes in both WT and Chop−/− mice. However, survival of RGCs in I/R-injured Chop−/− mouse was 48% higher (P < 0.05) than that in I/R-injured WT mouse 3 days after I/R injury. Similarly, RGC density was significantly higher in Chop−/− eyes at 7, 14, and 28 days after I/R injury. Scotopic threshold response amplitudes of Chop−/− mice were significantly higher at 3 and 7 days after I/R than those of WT mice. Conclusions. Absence of CHOP partially protects against RGC loss and reduction in retinal function after I/R injury, indicating that CHOP and, thus, ER stress play an important role in RGC apoptosis in retinal I/R injury. PMID:25414185

  13. Role of C/EBP homologous protein in retinal ganglion cell death after ischemia/reperfusion injury.

    PubMed

    Nashine, Sonali; Liu, Yang; Kim, Byung-Jin; Clark, Abbot F; Pang, Iok-Hou

    2014-11-20

    To investigate the role of C/EBP homologous protein (CHOP), a proapoptotic protein, and the unfolded protein response (UPR) marker that is involved in endoplasmic reticulum (ER) stress-mediated apoptosis in mouse retinal ganglion cell (RGC) death following ischemia/reperfusion (I/R) injury. Retinal I/R injury was induced in adult C57BL/6J wild-type (WT) and CHOP knockout (Chop(-/-)) mice by raising IOP to 120 mm Hg for 60 minutes. Expression of CHOP and other UPR markers was studied by Western blot and immunohistochemistry. Retinal ganglion cell counts were performed in retinal flat mounts stained with an RGC marker. Retinal ganglion cell function was evaluated by scotopic threshold response (STR) electroretinography. In WT mice, retinal CHOP was upregulated by 30% in I/R-injured eyes compared to uninjured eyes 3 days after injury (P < 0.05). Immunohistochemistry confirmed CHOP upregulation specifically in RGCs. CHOP knockout did not affect baseline RGC density or STR amplitude. Ischemia/reperfusion injury decreased RGC densities and STR amplitudes in both WT and Chop(-/-) mice. However, survival of RGCs in I/R-injured Chop(-/-) mouse was 48% higher (P < 0.05) than that in I/R-injured WT mouse 3 days after I/R injury. Similarly, RGC density was significantly higher in Chop(-/-) eyes at 7, 14, and 28 days after I/R injury. Scotopic threshold response amplitudes of Chop(-/-) mice were significantly higher at 3 and 7 days after I/R than those of WT mice. Absence of CHOP partially protects against RGC loss and reduction in retinal function after I/R injury, indicating that CHOP and, thus, ER stress play an important role in RGC apoptosis in retinal I/R injury. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  14. Ocular hypertension impairs optic nerve axonal transport leading to progressive retinal ganglion cell degeneration.

    PubMed

    Salinas-Navarro, Manuel; Alarcón-Martínez, Luis; Valiente-Soriano, Francisco J; Jiménez-López, Manuel; Mayor-Torroglosa, Sergio; Avilés-Trigueros, Marcelino; Villegas-Pérez, María Paz; Vidal-Sanz, Manuel

    2010-01-01

    Ocular hypertension (OHT) is the main risk factor of glaucoma, a neuropathy leading to blindness. Here we have investigated the effects of laser photocoagulation (LP)-induced OHT, on the survival and retrograde axonal transport (RAT) of adult rat retinal ganglion cells (RGC) from 1 to 12 wks. Active RAT was examined with fluorogold (FG) applied to both superior colliculi (SCi) 1 wk before processing and passive axonal diffusion with dextran tetramethylrhodamine (DTMR) applied to the optic nerve (ON) 2 d prior to sacrifice. Surviving RGCs were identified with FG applied 1 wk pre-LP or by Brn3a immunodetection. The ON and retinal nerve fiber layer were examined by RT97-neurofibrillar staining. RGCs were counted automatically and color-coded density maps were generated. OHT retinas showed absence of FG+ or DTMR+RGCs in focal, pie-shaped and diffuse regions of the retina which, by two weeks, amounted to, approximately, an 80% of RGC loss without further increase. At this time, there was a discrepancy between the total number of surviving FG-prelabelled RGCs and of DMTR+RGCs, suggesting that a large proportion of RGCs had their RAT impaired. This was further confirmed identifying surviving RGCs by their Brn3a expression. From 3 weeks onwards, there was a close correspondence of DTMR+RGCs and FG+RGCs in the same retinal regions, suggesting axonal constriction at the ON head. Neurofibrillar staining revealed, in ONs, focal degeneration of axonal bundles and, in the retinal areas lacking backlabeled RGCs, aberrant staining of RT97 characteristic of axotomy. LP-induced OHT results in a crush-like injury to ON axons leading to the anterograde and protracted retrograde degeneration of the intraocular axons and RGCs.

  15. Retinal ganglion cells in the eastern newt Notophthalmus viridescens: topography, morphology, and diversity.

    PubMed

    Pushchin, Igor I; Karetin, Yuriy A

    2009-10-20

    The topography and morphology of retinal ganglion cells (RGCs) in the eastern newt were studied. Cells were retrogradely labeled with tetramethylrhodamine-conjugated dextran amines or horseradish peroxidase and examined in retinal wholemounts. Their total number was 18,025 +/- 3,602 (mean +/- SEM). The spatial density of RGCs varied from 2,100 cells/mm(2) in the retinal periphery to 4,500 cells/mm(2) in the dorsotemporal retina. No prominent retinal specializations were found. The spatial resolution estimated from the spatial density of RGCs varied from 1.4 cycles per degree in the periphery to 1.95 cycles per degree in the region of the peak RGC density. A sample of 68 cells was camera lucida drawn and subjected to quantitative analysis. A total of 21 parameters related to RGC morphology and stratification in the retina were estimated. Partitionings obtained by using different clustering algorithms combined with automatic variable weighting and dimensionality reduction techniques were compared, and an effective solution was found by using silhouette analysis. A total of seven clusters were identified and associated with potential cell types. Kruskal-Wallis ANOVA-on-Ranks with post hoc Mann-Whitney U tests showed significant pairwise between-cluster differences in one or more of the clustering variables. The average silhouette values of the clusters were reasonably high, ranging from 0.52 to 0.79. Cells assigned to the same cluster displayed similar morphology and stratification in the retina. The advantages and limitations of the methodology adopted are discussed. The present classification is compared with known morphological and physiological RGC classifications in other salamanders.

  16. JUN is important for ocular hypertension-induced retinal ganglion cell degeneration.

    PubMed

    Syc-Mazurek, Stephanie B; Fernandes, Kimberly A; Libby, Richard T

    2017-07-20

    Ocular hypertension, a major risk factor for glaucoma, is thought to trigger glaucomatous neurodegeneration through injury to retinal ganglion cell (RGC) axons. The molecular signaling pathway leading from ocular hypertension to RGC degeneration, however, is not well defined. JNK signaling, a component of the mitogen-activated protein kinase (MAPK) family, and its canonical target, the transcription factor JUN, have been shown to regulate neurodegeneration in many different systems. JUN is expressed after glaucoma-relevant injuries and Jun deficiency protects RGCs after mechanical injury to the optic nerve. Here, we tested the importance of JNK-JUN signaling for RGC death after ocular hypertensive axonal injury in an age-related, mouse model of ocular hypertension. Immunohistochemistry was performed to evaluate JUN expression in ocular hypertensive DBA/2J mice. JUN was expressed in a temporal and spatial pattern consistent with a role in glaucomatous injury. To determine the importance of JUN in ocular hypertension-induced RGC death, a floxed allele of Jun and a retinal expressed cre recombinase (Six3-cre) were backcrossed onto the DBA/2J background. Intraocular pressure (IOP) and gross morphology of the retina and optic nerve head were assessed to determine whether removing Jun from the developing retina altered IOP elevation or retinal development. Jun deficiency in the retina did not alter DBA/2J IOP elevation or retinal development. Optic nerves and retinas were assessed at ages known to have glaucomatous damage in DBA/2J mice. Jun deficiency protected RGC somas from ocular hypertensive injury, but did not protect RGC axons from glaucomatous neurodegeneration. Jun is a major regulator of RGC somal degeneration after glaucomatous ocular hypertensive injury. These results suggest in glaucomatous neurodegeneration, JNK-JUN signaling has a major role as a pro-death signaling pathway between axonal injury and somal degeneration.

  17. In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

    PubMed Central

    Petros, Timothy J; Rebsam, Alexandra; Mason, Carol A

    2009-01-01

    The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell differentiation, axon guidance, retinotopic organization and synapse formation[1]. One drawback is the inability to efficiently and reliably manipulate gene expression in RGCs in vivo, especially in the otherwise accessible murine visual pathways. Transgenic mice can be used to manipulate gene expression, but this approach is often expensive, time consuming, and can produce unwanted side effects. In chick, in ovo electroporation is used to manipulate gene expression in RGCs for examining retina and RGC development. Although similar electroporation techniques have been developed in neonatal mouse pups[2], adult rats[3], and embryonic murine retinae in vitro[4], none of these strategies allow full characterization of RGC development and axon projections in vivo. To this end, we have developed two applications of electroporation, one in utero and the other ex vivo, to specifically target embryonic murine RGCs[5, 6]. With in utero retinal electroporation, we can misexpress or downregulate specific genes in RGCs and follow their axon projections through the visual pathways in vivo, allowing examination of guidance decisions at intermediate targets, such as the optic chiasm, or at target regions, such as the lateral geniculate nucleus. Perturbing gene expression in a subset of RGCs in an otherwise wild-type background facilitates an understanding of gene function throughout the retinal pathway. Additionally, we have developed a companion technique for analyzing RGC axon growth in vitro. We electroporate embryonic heads ex vivo, collect and incubate the whole retina, then prepare explants from these retinae several days later. Retinal explants can be used in a variety of in vitro assays in order to examine the response of electroporated RGC axons to guidance cues or other factors. In sum, this set of techniques enhances

  18. Responses of rabbit retinal ganglion cells to electrical stimulation with an epiretinal electrode

    NASA Astrophysics Data System (ADS)

    Jensen, Ralph J.; Ziv, Ofer R.; Rizzo, Joseph F.

    2005-03-01

    Rational selection of electrical stimulus parameters for an electronic retinal prosthesis requires knowledge of the electrophysiological responses of retinal neurons to electrical stimuli. In this study, we examined the effects of cathodal and anodal current pulses on the extracellularly recorded responses of OFF and ON rabbit retinal ganglion cells (RGCs) in an in vitro preparation. Current pulses (1 msec duration), delivered by a 125 µm electrode placed on the inner retinal surface within the receptive field of a RGC, produced both short-latency (<=5 msec) and long-latency (8-60 msec) responses. The long-latency responses, but not the short-latency responses, were abolished upon application of the glutamate receptor antagonists CNQX and NBQX, thus indicating that the long-latency responses of RGCs are due to activation of presynaptic neurons in the retina. The latency of the long-latency response depended upon the polarity of the stimulus. For OFF RGCs, the average latency was 11 msec for a cathodal stimulus and 24 msec for an anodal stimulus. For ON RGCs, the average latency was 25 msec for a cathodal stimulus and 16 msec for an anodal stimulus. The threshold current also depended upon the polarity of the stimulus, at least for OFF RGCs. The average threshold current for evoking a long-latency response in OFF RGCs was 10 µA for a cathodal stimulus and 21 µA for an anodal stimulus. In ON RGCs, the average threshold current was 13 µA for a cathodal stimulus and 15 µA for an anodal stimulus.

  19. Synchronized Firings in Retinal Ganglion Cells in Response to Natural Stimulation

    NASA Astrophysics Data System (ADS)

    Zhang, Ying-Ying; Xiao, Lei; Liu, Wen-Zhong; Gong, Hai-Qing; Liang, Pei-Ji

    2011-02-01

    The response of synchronously firing groups of population retinal ganglion cells (RGCs) to natural movies (NMs) and pseudo-random white-noise checker-board flickering (CB, as control) are investigated using an information-theoretic algorithm. The main results are: (1) the population RGCs tend to fire in synchrony far more frequently than expected by chance during both NM and CB stimulation; (2) more synchronous groups could be formed and each group contains more neurons under NM than CB stimulation; (3) the individual neurons also participate in more groups and have more distinct partners in NM than CB stimulation. All these results suggest that the synchronized firings in RGCs are more extensive and diverse, which may account for more effective information processing in representing the natural visual environment.

  20. Imaging light responses of retinal ganglion cells in the living mouse eye

    PubMed Central

    Yin, Lu; Geng, Ying; Osakada, Fumitaka; Sharma, Robin; Cetin, Ali H.; Callaway, Edward M.; Williams, David R.

    2013-01-01

    This study reports development of a novel method for high-resolution in vivo imaging of the function of individual mouse retinal ganglion cells (RGCs) that overcomes many limitations of available methods for recording RGC physiology. The technique combines insertion of a genetically encoded calcium indicator into RGCs with imaging of calcium responses over many days with FACILE (functional adaptive optics cellular imaging in the living eye). FACILE extends the most common method for RGC physiology, in vitro physiology, by allowing repeated imaging of the function of each cell over many sessions and by avoiding damage to the retina during removal from the eye. This makes it possible to track changes in the response of individual cells during morphological development or degeneration. FACILE also overcomes limitations of existing in vivo imaging methods, providing fine spatial and temporal detail, structure-function comparison, and simultaneous analysis of multiple cells. PMID:23407356

  1. Dendritic and synaptic protection: is it enough to save the retinal ganglion cell body and axon?

    PubMed

    Morquette, Junie Barbara; Di Polo, Adriana

    2008-06-01

    Glaucoma and other optic neuropathies have been traditionally viewed as diseases of the optic nerve that lead to retinal ganglion cell (RGC) degeneration. Accordingly, the primary aim of neuroprotective strategies has been to preserve RGC axons and soma. RGCs are complex and highly polarized central neurons, and their pathologic response in disease is likely to be an integration of signals from all cellular compartments-axons, soma, dendrites, and synaptic contacts. We focus on the role of dendrites and dendritic spines in normal neuronal function, neurologic disorders, and glaucoma. The need to understand the mechanisms underlying RGC dendrite and synapse degeneration in glaucoma and other optic neuropathies is compelling, as it may provide insight into novel therapeutic strategies to prevent vision loss.

  2. Optic neuropathies: characteristic features and mechanisms of retinal ganglion cell loss.

    PubMed

    You, Yuyi; Gupta, Vivek K; Li, Jonathan C; Klistorner, Alexander; Graham, Stuart L

    2013-01-01

    Optic neuropathy refers to dysfunction and/or degeneration of axons of the optic nerve with subsequent optic nerve atrophy. A common feature of different optic neuropathies is retinal ganglion cell (RGC) apoptosis and axonal damage. Glaucoma and optic neuritis are the two major degenerative causes of optic nerve damage. Here, we review the anatomy and pathology of the optic nerve, and etiological categories of optic neuropathies, and discuss rodent models that can mimic these conditions. Electrophysiology can reveal signature features of RGC damage using the pattern electroretinogram (PERG), scotopic threshold response (STR) and photopic negative response (PhNR). The amplitude of the visual evoked potential (VEP) also reflects RGC axonal damage. The neurotrophin-mediated survival pathways, as well as the extrinsic and intrinsic cell apoptotic pathways, play a critical role in the pathogenesis of RGC loss. Finally, promising neuroprotective approaches based on the molecular signaling are analyzed for the treatment of optic neuropathies.

  3. Regenerative Responses and Axon Pathfinding of Retinal Ganglion Cells in Chronically Injured Mice

    PubMed Central

    Yungher, Benjamin J.; Ribeiro, Márcio; Park, Kevin K.

    2017-01-01

    Purpose Enhanced regeneration of retinal ganglion cell (RGC) axons can be achieved by modification of numerous neuronal-intrinsic factors. However, axon growth initiation and the pathfinding behavior of these axons after traumatic injury remain poorly understood outside of acute injury paradigms, despite the clinical relevance of more chronic settings. We therefore examined RGC axon regeneration following therapeutic delivery that is postponed until 2 months after optic nerve crush injury. Methods Optic nerve regeneration was induced by virally mediated (adeno-associated virus) ciliary neurotrophic factor (AAV-CNTF) administered either immediately or 56 days after optic nerve crush in wild-type or Bax knockout (KO) mice. Retinal ganglion nerve axon regeneration was assessed 21 and 56 days after viral injection. Immunohistochemical analysis of RGC injury signals and extrinsic factors in the optic nerve were also examined at 5 and 56 days post crush. Results In addition to sustained expression of injury response proteins in surviving RGCs, we observe axon regrowth in wild-type and apoptosis-deficient Bax KO mice following AAV-CNTF treatment. Fewer instances of aberrant axon growth are seen, at least in the area near the lesion site, in animals given treatment 56 days after crush injury compared to the animals given treatment immediately after injury. We also find evidence of long distance growth into a visual target in Bax KO mice despite postponed initiation of this regenerative program. Conclusions These studies provide evidence against an intrinsic critical period for RGC axon regeneration or degradation of injury signals. Regeneration results from Bax KO mice imply highly sustained regenerative capacity in RGCs, highlighting the importance of long-lasting neuroprotective strategies as well as of RGC axon guidance research in chronically injured animals. PMID:28324115

  4. Retinal Ganglion Cell Damage in an Experimental Rodent Model of Blast-Mediated Traumatic Brain Injury

    PubMed Central

    Mohan, Kabhilan; Kecova, Helga; Hernandez-Merino, Elena; Kardon, Randy H.; Harper, Matthew M.

    2013-01-01

    Purpose. To evaluate retina and optic nerve damage following experimental blast injury. Methods. Healthy adult mice were exposed to an overpressure blast wave using a custom-built blast chamber. The effects of blast exposure on retina and optic nerve function and structure were evaluated using the pattern electroretinogram (pERG), spectral domain optical coherence tomography (OCT), and the chromatic pupil light reflex. Results. Assessment of the pupil response to light demonstrated decreased maximum pupil constriction diameter in blast-injured mice using red light or blue light stimuli 24 hours after injury compared with baseline in the eye exposed to direct blast injury. A decrease in the pupil light reflex was not observed chronically following blast exposure. We observed a biphasic pERG decrease with the acute injury recovering by 24 hours postblast and the chronic injury appearing at 4 months postblast injury. Furthermore, at 3 months following injury, a significant decrease in the retinal nerve fiber layer was observed using OCT compared with controls. Histologic analysis of the retina and optic nerve revealed punctate regions of reduced cellularity in the ganglion cell layer and damage to optic nerves. Additionally, a significant upregulation of proteins associated with oxidative stress was observed acutely following blast exposure compared with control mice. Conclusions. Our study demonstrates that decrements in retinal ganglion cell responses can be detected after blast injury using noninvasive functional and structural tests. These objective responses may serve as surrogate tests for higher CNS functions following traumatic brain injury that are difficult to quantify. PMID:23620426

  5. Rescuing axons from degeneration does not affect retinal ganglion cell death

    PubMed Central

    de Lima, S.; Mietto, B.S.; Paula, C.; Muniz, T.; Martinez, A.M.B.; Gardino, P.F.

    2016-01-01

    After a traumatic injury to the central nervous system, the distal stumps of axons undergo Wallerian degeneration (WD), an event that comprises cytoskeleton and myelin breakdown, astrocytic gliosis, and overexpression of proteins that inhibit axonal regrowth. By contrast, injured neuronal cell bodies show features characteristic of attempts to initiate the regenerative process of elongating their axons. The main molecular event that leads to WD is an increase in the intracellular calcium concentration, which activates calpains, calcium-dependent proteases that degrade cytoskeleton proteins. The aim of our study was to investigate whether preventing axonal degeneration would impact the survival of retinal ganglion cells (RGCs) after crushing the optic nerve. We observed that male Wistar rats (weighing 200-400 g; n=18) treated with an exogenous calpain inhibitor (20 mM) administered via direct application of the inhibitor embedded within the copolymer resin Evlax immediately following optic nerve crush showed a delay in the onset of WD. This delayed onset was characterized by a decrease in the number of degenerated fibers (P<0.05) and an increase in the number of preserved fibers (P<0.05) 4 days after injury. Additionally, most preserved fibers showed a normal G-ratio. These results indicated that calpain inhibition prevented the degeneration of optic nerve fibers, rescuing axons from the process of axonal degeneration. However, analysis of retinal ganglion cell survival demonstrated no difference between the calpain inhibitor- and vehicle-treated groups, suggesting that although the calpain inhibitor prevented axonal degeneration, it had no effect on RGC survival after optic nerve damage. PMID:27007653

  6. Absence of galectin-3 promotes neuroprotection in retinal ganglion cells after optic nerve injury.

    PubMed

    Abreu, Carla Andreia; De Lima, Silmara Veline; Mendonça, Henrique Rocha; Goulart, Camila de Oliveira; Martinez, Ana Maria Blanco

    2017-03-01

    A trauma to the mature central nervous system (CNS) often leads to persistent deficits, due to the inability of axons to regenerate after being injured. Increasing evidence suggests that pro-inflammatory and pro-apoptotic genes can present a major obstacle to promoting neuroprotection of retinal ganglion cells and consequently succeed in axonal regeneration. This study evaluated the effect of the absence of galectin-3 (Gal-3) on retinal ganglion cells (RGC) survival and axonal regeneration/degeneration after optic nerve crush injury. Two weeks after crush there was a 2.6 fold increase in the rate of cell survival in Gal-3-/- mice (1283±79.15) compared to WT animals (495.4±53.96). However, no regeneration was observed in the Gal-3-/- mice two weeks after lesion. Furthermore, axonal degeneration presented a particular pattern on those mice; Electron Microscopy (EM) analysis showed incomplete axon degeneration while the WT mice presented an advanced stage of degeneration. This suggests that the removal of the nerve fibers in the Gal 3-/- mice could be deficient and this would cause a delay in the process of Wallerian degeneration once there is a decrease in the number of macrophages/microglia in the nerve. This study demonstrates how the absence of Gal-3 can affect RGC survival and optic nerve regeneration/degeneration after lesion. Our results suggest that the absence of Gal-3 plays an important role in the survival of RGC and thus can be a potential target for therapeutic intervention in RGC neuroprotection.

  7. Retinal ganglion cell neuroprotection induced by activation of alpha7 nicotinic acetylcholine receptors

    PubMed Central

    Mata, David; Linn, David M.

    2015-01-01

    The α7nAChR agonist, PNU-282987, has previously been shown to have a neuroprotective effect against loss of retinal ganglion cells (RGCs) in an in vivo glaucoma model when the agent was injected into the vitreous chamber of adult Long Evans rat eyes. Here, we characterized the neuroprotective effect of PNU-282987 at the nerve fiber and retinal ganglion cell layer, determined that neuroprotection occurred when the agonist was applied as eye drops and verified detection of the agonist in the retina, using LC/MS/MS. To induce glaucoma-like conditions in adult Long Evans rats, hypertonic saline was injected into the episcleral veins to induce scar tissue and increase intraocular pressure. Within one month, this procedure produced significant loss of RGCs compared to untreated conditions. RGCs were quantified after immunostaining with an antibody against Thy 1.1 and imaged using a confocal microscope. In dose-response studies, concentrations of PNU-282987 were applied to the animal’s right eye two times each day, while the left eye acted as an internal control. Eye drops of PNU-282987 resulted in neuroprotection against RGC loss in a dose-dependent manner using concentrations between 100 µM and 2 mM PNU-282987. LC/MS/MS results demonstrated that PNU-282987 was detected in the retina when applied as eye drops, relatively small amounts of PNU-282987 were measured in blood plasma and no PNU-282987 was detected in cardiac tissue. These results support the hypothesis that eye drop application of PNU-282987 can prevent loss of RGCs associated with glaucoma, which can lead to neuroprotective treatments for diseases that involve α7nAChRs. PMID:26239818

  8. Separability of stimulus parameter encoding by on-off directionally selective rabbit retinal ganglion cells

    PubMed Central

    Nowak, Przemyslaw; Dobbins, Allan C.; Gawne, Timothy J.; Grzywacz, Norberto M.

    2011-01-01

    The ganglion cell output of the retina constitutes a bottleneck in sensory processing in that ganglion cells must encode multiple stimulus parameters in their responses. Here we investigate encoding strategies of On-Off directionally selective retinal ganglion cells (On-Off DS RGCs) in rabbits, a class of cells dedicated to representing motion. The exquisite axial discrimination of these cells to preferred vs. null direction motion is well documented: it is invariant with respect to speed, contrast, spatial configuration, spatial frequency, and motion extent. However, these cells have broad direction tuning curves and their responses also vary as a function of other parameters such as speed and contrast. In this study, we examined whether the variation in responses across multiple stimulus parameters is systematic, that is the same for all cells, and separable, such that the response to a stimulus is a product of the effects of each stimulus parameter alone. We extracellularly recorded single On-Off DS RGCs in a superfused eyecup preparation while stimulating them with moving bars. We found that spike count responses of these cells scaled as independent functions of direction, speed, and luminance. Moreover, the speed and luminance functions were common across the whole sample of cells. Based on these findings, we developed a model that accurately predicted responses of On-Off DS RGCs as products of separable functions of direction, speed, and luminance (r = 0.98; P < 0.0001). Such a multiplicatively separable encoding strategy may simplify the decoding of these cells' outputs by the higher visual centers. PMID:21325684

  9. Observations on the mode of action of some central depressant drugs on transmission through the cat superior cervical ganglion

    PubMed Central

    Brown, D. A.; Quilliam, J. P.

    1964-01-01

    Methylpentynol, paraldehyde, amylobarbitone and procainamide blocked transmission through the cat superior cervical ganglion, and antagonized the ganglion-stimulating actions of acetylcholine and carbachol injected intra-arterially to the ganglion. Comparison with the effects of tetraethylammonium indicated that the impaired response to acetylcholine could not wholly account for the failure of transmission, which suggested that an impaired release of transmitter substance was a contributory factor. Methylpentynol, paraldehyde and procainamide also blocked the ganglion-stimulating action of potassium chloride. In contrast, amylobarbitone and pentobarbitone did not block the stimulating action of potassium chloride, but antagonized specifically the actions of acetylcholine and carbachol. The anti-acetylcholine activities of the two barbiturate drugs at this site accord with their relative ganglion-blocking activities. It is concluded that the ganglion-blocking action of methylpentynol, paraldehyde and procainamide arises from a nonspecific depression of both presynaptic and postsynaptic elements in the ganglion, but that barbiturate compounds act more specifically on the acetylcholine receptor. PMID:14228128

  10. Coding Properties of Three Intrinsically Distinct Retinal Ganglion Cells under Periodic Stimuli: A Computational Study

    PubMed Central

    Wang, Lei; Qiu, Yi-Hong; Zeng, Yanjun

    2016-01-01

    As the sole output neurons in the retina, ganglion cells play significant roles in transforming visual information into spike trains, and then transmitting them to the higher visual centers. However, coding strategies that retinal ganglion cells (RGCs) adopt to accomplish these processes are not completely clear yet. To clarify these issues, we investigate the coding properties of three types of RGCs (repetitive spiking, tonic firing, and phasic firing) by two different measures (spike-rate and spike-latency). Model results show that for periodic stimuli, repetitive spiking RGC and tonic RGC exhibit similar spike-rate patterns. Their spike- rates decrease gradually with increased stimulus frequency, moreover, variation of stimulus amplitude would change the two RGCs' spike-rate patterns. For phasic RGC, it activates strongly at medium levels of frequency when the stimulus amplitude is low. While if high stimulus amplitude is applied, phasic RGC switches to respond strongly at low frequencies. These results suggest that stimulus amplitude is a prominent factor in regulating RGCs in encoding periodic signals. Similar conclusions can be drawn when analyzes spike-latency patterns of the three RGCs. More importantly, the above phenomena can be accurately reproduced by Hodgkin's three classes of neurons, indicating that RGCs can perform the typical three classes of firing dynamics, depending on the distinctions of ion channel densities. Consequently, model results from the three RGCs may be not specific, but can also applicable to neurons in other brain regions which exhibit part(s) or all of the Hodgkin's three excitabilities. PMID:27721751

  11. Upregulation of Gem relates to retinal ganglion cells apoptosis after optic nerve crush in adult rats.

    PubMed

    Xu, Fan; Huang, Hui; Wu, Yu; Lu, Lu; Jiang, Li; Chen, Lifei; Zeng, Siming; Li, Li; Li, Min

    2014-10-01

    GTP-binding protein Gem, a member protein of the Ras superfamily, can regulate actin cytoskeleton reorganization mediated by Rho-associated coiled-coil-containing protein kinase (ROCK). One attractive activity of the ROCK is playing a potential role in physiological and pathological process in retinal ganglion cells (RGCs) apoptosis. However, the function of Gem in retina is still with limited understanding. To investigate whether Gem is involved in optic nerve injury, we performed an optic nerve crush (ONC) model in adult rats. Western blot analysis indicated that Gem was significantly increased in the retina at the 3rd day after ONC. Meanwhile, double-immunofluorescent staining showed that Gem expression was mainly up-regulated in ganglion cell layer and co-localized with NeuN (a marker of RGCs). Additionally, the co-localizations of Gem/active-caspase-3 and Gem/TUNEL-positive cells were detected in RGCs. Furthermore, the expression of active-caspase-3 and TUNEL-positive cells was parallel with that of Gem. Finally, expression pattern of ROCK family (only ROCK2 but not ROCK1) was increased in the differentiated process, which was collected with the expression of GEM and active-caspase-3. Based on the present results, it is suggested that Gem might play a crucial role in RGCs apoptosis after ONC, which might be involved in ROCK pathway.

  12. Visual pattern discrimination by population retinal ganglion cells' activities during natural movie stimulation.

    PubMed

    Zhang, Ying-Ying; Wang, Ru-Bin; Pan, Xiao-Chuan; Gong, Hai-Qing; Liang, Pei-Ji

    2014-02-01

    In the visual system, neurons often fire in synchrony, and it is believed that synchronous activities of group neurons are more efficient than single cell response in transmitting neural signals to down-stream neurons. However, whether dynamic natural stimuli are encoded by dynamic spatiotemporal firing patterns of synchronous group neurons still needs to be investigated. In this paper we recorded the activities of population ganglion cells in bullfrog retina in response to time-varying natural images (natural scene movie) using multi-electrode arrays. In response to some different brief section pairs of the movie, synchronous groups of retinal ganglion cells (RGCs) fired with similar but different spike events. We attempted to discriminate the movie sections based on temporal firing patterns of single cells and spatiotemporal firing patterns of the synchronous groups of RGCs characterized by a measurement of subsequence distribution discrepancy. The discrimination performance was assessed by a classification method based on Support Vector Machines. Our results show that different movie sections of the natural movie elicited reliable dynamic spatiotemporal activity patterns of the synchronous RGCs, which are more efficient in discriminating different movie sections than the temporal patterns of the single cells' spike events. These results suggest that, during natural vision, the down-stream neurons may decode the visual information from the dynamic spatiotemporal patterns of the synchronous group of RGCs' activities.

  13. ADAM10 mediates N-cadherin ectodomain shedding during retinal ganglion cell differentiation in primary cultured retinal cells from the developing chick retina.

    PubMed

    Paudel, Sharada; Kim, Yeoun-Hee; Huh, Man-Il; Kim, Song-Ja; Chang, Yongmin; Park, Young Jeung; Lee, Kyoo Won; Jung, Jae-Chang

    2013-04-01

    Here, we examined the role of ADAM10 during retinal cell differentiation in retinal sections and in vitro cultures of developing chick retinal cells from embryonic day 6 (ED6). Immunohistochemistry showed that ADAM10 is abundantly expressed in the inner zone of neuroblastic layer at ED5, and it becomes more highly expressed in the ganglion cell layer at ED7 and ED9. Western blotting confirmed that ADAM10 was expressed as an inactive pro-form that was processed to a shorter, active form in control cultured cells, but in cultures treated with an ADAM10 inhibitor (GI254023X) and ADAM10-specific siRNA, the level of mature ADAM10 decreased. Phase-contrast microscopy showed that long neurite extensions were present in untreated cultures 24 h after plating, whereas cultures treated with GI254023X showed significant decreases in neurite extension. Immunofluorescence staining revealed that there were far fewer differentiated ganglion cells in ADAM10 siRNA and GI254023X-treated cultures compared to controls, whereas the photoreceptor cells were unaltered. The Pax6 protein was more strongly detected in the differentiated ganglion cells of control cultures compared to ADAM10 siRNA and GI254023X-treated cultures. N-cadherin ectodomain shedding was apparent in control cultures after 24 h, when ganglion cell differentiation was observed, but ADAM10 siRNA and GI254023X treatment inhibited these processes. In contrast, N-cadherin staining was strongly detected in photoreceptor cells regardless of ADAM10 siRNA and GI254023X treatment. Taken together, these data indicate that the inhibition of ADAM10 can inhibit Pax6 expression and N-cadherin ectodomain shedding in retinal cells, possibly affecting neurite outgrowth and ganglion cell differentiation.

  14. Alkaline Phosphatase distribution in the inferior vagal ganglion of the cat following vagotomy: a chronological study.

    PubMed

    Glover, R A

    1976-10-07

    The object of this study was to demonstrate sites of alkaline phosphatase activity within the cellular elements of the inferior vagal (nodosal) ganglion of the cat and chronologically observe and describe alterations in enzyme activity following vagotomy. In control tissues alkaline phosphatase activity was localized to the wall of perineuronal blood vessels and the satellite cell cytoplasm which envelops the neuronal perikarya. In the experimental tissues alkaline phosphatase activity was increased in the above locations during the first 20 days following vagotomy then gradually declined to approximate control levels by 60 days post-operatively. The functional significance of changes in alkaline phosphatase activity occurring within an altered metabolic environment induced by vagotomy is discussed.

  15. Endothelins in the cat petrosal ganglion and carotid body: effects and immunolocalization.

    PubMed

    Rey, Sergio; Del Rio, Rodrigo; Alcayaga, Julio; Iturriaga, Rodrigo

    2006-01-19

    In response to hypoxia, chemoreceptor cells of the carotid body (CB) release transmitters, which acting on the petrosal ganglion (PG) neuron terminals, increase the chemoafferent discharge. Additionally, vasoactive molecules produced within the CB may modulate hypoxic chemoreception by controlling blood flow and tissue PO2. Endothelin-1 (ET-1) increases basal CB chemosensory discharges in situ, probably due to its vasoconstrictor action. However, the actions of ET-1 on PG neurons or its expression in the PG are not known. Using immunohistochemistry, we found that endothelin-like peptides are expressed in the cat PG and CB under normoxic conditions. Exogenous applications of ET-1 increased the chemosensory activity in the vascularly perfused CB but were ineffective on either the CB or PG superfused preparations, both of which are devoid of vascular control. Thus, our data indicate that the excitatory effect of ET-1 in the carotid chemoreceptor system appears to be mainly due to a vasoconstrictor effect in the CB blood vessels.

  16. Gender difference in the neuroprotective effect of rat bone marrow mesenchymal cells against hypoxia-induced apoptosis of retinal ganglion cells.

    PubMed

    Yuan, Jing; Yu, Jian-Xiong

    2016-05-01

    Bone marrow mesenchymal stem cells can reduce retinal ganglion cell death and effectively prevent vision loss. Previously, we found that during differentiation, female rhesus monkey bone marrow mesenchymal stem cells acquire a higher neurogenic potential compared with male rhesus monkey bone marrow mesenchymal stem cells. This suggests that female bone marrow mesenchymal stem cells have a stronger neuroprotective effect than male bone marrow mesenchymal stem cells. Here, we first isolated and cultured bone marrow mesenchymal stem cells from female and male rats by density gradient centrifugation. Retinal tissue from newborn rats was prepared by enzymatic digestion to obtain primary retinal ganglion cells. Using the transwell system, retinal ganglion cells were co-cultured with bone marrow mesenchymal stem cells under hypoxia. Cell apoptosis was detected by flow cytometry and caspase-3 activity assay. We found a marked increase in apoptotic rate and caspase-3 activity of retinal ganglion cells after 24 hours of hypoxia compared with normoxia. Moreover, apoptotic rate and caspase-3 activity of retinal ganglion cells significantly decreased with both female and male bone marrow mesenchymal stem cell co-culture under hypoxia compared with culture alone, with more significant effects from female bone marrow mesenchymal stem cells. Our results indicate that bone marrow mesenchymal stem cells exert a neuroprotective effect against hypoxia-induced apoptosis of retinal ganglion cells, and also that female cells have greater neuroprotective ability compared with male cells.

  17. Norrin treatment improves ganglion cell survival in an oxygen-induced retinopathy model of retinal ischemia.

    PubMed

    Dailey, Wendy A; Drenser, Kimberly A; Wong, Sui Chien; Cheng, Mei; Vercellone, Joseph; Roumayah, Kevin K; Feeney, Erin V; Deshpande, Mrinalini; Guzman, Alvaro E; Trese, Michael; Mitton, Kenneth P

    2017-08-18

    Treatment of a mouse model of oxygen-induced retinopathy (OIR) with recombinant human Norrin (Norrie Disease Protein, gene: NDP) accelerates regrowth of the microvasculature into central ischemic regions of the neural retina, which are generated after treatment with 75% oxygen. While this reduces the average duration and severity of ischemia overall, we do not know if this accelerated recovery of the microvasculature results in any significant survival of retinal ganglion cells (RGCs). The purpose of this study was to investigate ganglion cell survival with and without the intravitreal injection of Norrin in the murine model of oxygen induced retinopathy (OIR), using two strains of mice: C57BL/6J and Thy1-YFP mice. Intravitreal injections of Norrin or vehicle were done after five days of exposure to 75% oxygen from ages P7 to P12. The C57BL/J mice were followed by Spectral-Domain Optical Coherence Tomography (SD-OCT), and the average nerve fiber layer (NFL) and inner-plexiform layer (IPL) thicknesses were measured at twenty-four locations per retina at P42. Additionally, some C57BL/J retinas were flat mounted and immunostained for the RGC marker, Brn3a, to compare the population density of surviving retinal ganglion cells. Using homozygous Thy1-YFP mice, single intrinsically fluorescent RGCs were imaged in live animals with a Micron-III imaging system at ages P21, 28 and P42. The relative percentage of YFP-fluorescent RGCs with dendritic arbors were compared. At age P42, the NFL was thicker in Norrin-injected OIR eyes, 14.4 μm, compared to Vehicle-injected OIR eyes, 13.3 μm (p = 0.01). In the superior retina, the average thickness of the IPL was greater in Norrin-injected OIR eyes, 37.7 μm, compared to Vehicle-injected OIR eyes, 34.6 μm (p = 0.04). Retinas from Norrin injected OIR mice had significantly more surviving RGCs (p = 0.03) than vehicle-injected mice. Based upon NFL thickness and counts of RGCs, we conclude that Norrin treatment, early in

  18. Effect of alpha lipoic acid on retinal ganglion cell survival in an optic nerve crush model

    PubMed Central

    Liu, Ruixing; Wang, Yanling; Pu, Mingliang

    2016-01-01

    Purpose This study was conducted to determine whether alpha lipoic acid (ALA) promotes the survival of retinal ganglion cells (RGCs) in a rat model of optic nerve crush (ONC) injury and to investigate the neuroprotective mechanisms of ALA in the retina in this ONC injury model. Methods Adult male Sprague-Dawley rats (180–220 g) were subjected to ONC injury surgery. ALA (63 mg/kg) was injected intravenously 1 day before or after the ONC injury. Animals were euthanized after 10 days, and the number of ganglion cells positive for RNA-binding protein with multiple splicing (Rbpms), which is an RGC marker, were counted on the whole mount retinas. In addition, immunofluorescence and immunoblotting were performed to examine the localization and levels of erythropoietin receptor (EPOR) and neurotrophin-4/5 (NT4/5) in the retinas in all experimental groups. To determine whether the EPO/EPOR signaling pathway was involved in the ALA antioxidant pathway, the rats were subjected to ruxolitinib (INCB018424, 0.25 mg/kg, bid, intraperitoneal, i.p.) treatment after the animals were injected intravenously with ALA 1 day before ONC injury. Results The average number of Rbpms-positive cells/mm2 in the control group (sham-operated group), the ONC group, the ALA-ONC group, and the ONC-ALA group retinas was 2219±28, 418±8, 848±22, and 613±18/mm2, respectively. The ALA-ONC and ONC-ALA groups showed a statistically significantly increased RGC survival rate compared to the ONC group. There were statistical differences in the RGC survival rates between the ALA-ONC (39%) and ONC-ALA groups (28%; p<0.05). Immunofluorescent labeling showed that EPOR and NT4/5 expression was significant in the retinal ganglion cell layer (GCL). At the same time, western blot analysis revealed that ALA induced upregulation of EPOR protein and NT4/5 protein expression in the retina after ONC injury. However, INCB018424 reversed the protective effects of ALA on the ONC retinas. Conclusions ALA has

  19. Intravitreal injection of forskolin, homotaurine, and L-carnosine affords neuroprotection to retinal ganglion cells following retinal ischemic injury

    PubMed Central

    Adornetto, Annagrazia; Cavaliere, Federica; Varano, Giuseppe Pasquale; Rusciano, Dario; Morrone, Luigi Antonio; Corasaniti, Maria Tiziana; Bagetta, Giacinto; Nucci, Carlo

    2015-01-01

    Purpose Retinal ganglion cell (RGC) death is the final event leading to visual impairment in glaucoma; therefore, identification of neuroprotective strategies able to slow down or prevent the process is one of the main challenges for glaucoma research. The purpose of this study was to evaluate the neuroprotective potential of RGC death induced by the in vivo transient increase in intraocular pressure (IOP) of a combined treatment with forskolin, homotaurine, and L-carnosine. Forskolin (7beta-acetoxy-8, 13-epoxy-1a, 6β, 9a-trihydroxy-labd-14-en-11-one) is an activator of adenylate cyclase that decreases IOP by reducing aqueous humor production and functions as a neuroprotector due to its neurotrophin-stimulating activity. Homotaurine is a natural aminosulfonate compound endowed with neuromodulatory effects, while the dipeptide L-carnosine is known for its antioxidant properties. Methods Retinal ischemia was induced in the right eye of adult male Wistar rats by acutely increasing the IOP. Forskolin, homotaurine, and L-carnosine were intravitreally injected and RGC survival evaluated following retrograde labeling with FluoroGold. Total and phosphorylated Akt and glycogen synthase kinase-3β (GSK-3β) protein levels, as well as calpain activity, were analyzed with western blot. Protein kinase A (PKA) was inhibited by intravitreal injection of H89. Results A synergic neuroprotective effect on RGC survival was observed following the combined treatment with forskolin, homotaurine, and L-carnosine compared to forskolin alone. The observed neuroprotection was associated with reduced calpain activity, upregulation of phosphoinositide 3-kinase (PI3K)/Akt pathway, and inhibition of GSK-3β but was independent from PKA activation and distinct from the hypotensive effects of forskolin. Conclusions A multidrug/multitarget approach, by interfering with several pathways involved in RGC degeneration, may be promising to achieve glaucoma neuroprotection. PMID:26167113

  20. Ephrin-B2 elicits differential growth cone collapse and axon retraction in retinal ganglion cells from distinct retinal regions

    PubMed Central

    Petros, Timothy J.; Bryson, J. Barney; Mason, Carol

    2010-01-01

    The circuit for binocular vision and stereopsis is established at the optic chiasm, where retinal ganglion cell (RGC) axons diverge into the ipsilateral and contralateral optic tracts. In the mouse retina, ventrotemporal (VT) RGCs express the guidance receptor EphB1, which interacts with the repulsive guidance cue ephrin-B2 on radial glia at the optic chiasm to direct VT RGC axons ipsilaterally. RGCs in the ventral retina also express EphB2, which interacts with ephrin-B2, whereas dorsal RGCs express low levels of EphB receptors. To investigate how growth cones of RGCs from different retinal regions respond upon initial contact with ephrin-B2, we utilized time-lapse imaging to characterize the effects of ephrin-B2 on growth cone collapse and axon retraction in real time. We demonstrate that bath application of ephrin-B2 induces rapid and sustained growth cone collapse and axon retraction in VT RGC axons, whereas contralaterally-projecting dorsotemporal RGCs display moderate growth cone collapse and little axon retraction. Dose response curves reveal that contralaterally-projecting ventronasal axons are less sensitive to ephrin-B2 treatment compared to VT axons. Additionally, we uncovered a specific role for Rho kinase signaling in the retraction of VT RGC axons but not in growth cone collapse. The detailed characterization of growth cone behavior in this study comprises an assay for the study of Eph signaling in RGCs, and provides insight into the phenomena of growth cone collapse and axon retraction in general. PMID:20629048

  1. Ipsilateral and Contralateral Retinal Ganglion Cells Express Distinct Genes during Decussation at the Optic Chiasm

    PubMed Central

    Marcucci, Florencia; Cerullo, Isadora

    2016-01-01

    The increasing availability of transcriptomic technologies within the last decade has facilitated high-throughput identification of gene expression differences that define distinct cell types as well as the molecular pathways that drive their specification. The retinal projection neurons, retinal ganglion cells (RGCs), can be categorized into distinct morphological and functional subtypes and by the laterality of their projections. Here, we present a method for purifying the sparse population of ipsilaterally projecting RGCs in mouse retina from their contralaterally projecting counterparts during embryonic development through rapid retrograde labeling followed by fluorescence-activated cell sorting. Through microarray analysis, we uncovered the distinct molecular signatures that define and distinguish ipsilateral and contralateral RGCs during the critical period of axonal outgrowth and decussation, with more than 300 genes differentially expressed within these two cell populations. Among the differentially expressed genes confirmed through in vivo expression validation, several genes that mark “immaturity” are expressed within postmitotic ipsilateral RGCs. Moreover, at least one complementary pair, Igf1 and Igfbp5, is upregulated in contralateral or ipsilateral RGCs, respectively, and may represent signaling pathways that determine ipsilateral versus contralateral RGC identity. Importantly, the cell cycle regulator cyclin D2 is highly expressed in peripheral ventral retina with a dynamic expression pattern that peaks during the period of ipsilateral RGC production. Thus, the molecular signatures of ipsilateral and contralateral RGCs and the mechanisms that regulate their differentiation are more diverse than previously expected. PMID:27957530

  2. Elevated intracranial pressure causes optic nerve and retinal ganglion cell degeneration in mice

    PubMed Central

    Nusbaum, Derek M.; Wu, Samuel M.; Frankfort, Benjamin J.

    2015-01-01

    The purpose of this study was to develop a novel experimental system for the modulation and measurement of intracranial pressure (ICP), and to use this system to assess the impact of elevated ICP on the optic nerve and retinal ganglion cells (RGCs) in CD1 mice. This system involved surgical implantation of an infusion cannula and a radiowave based pressure monitoring probe through the skull and into the subarachnoid space. The infusion cannula was used to increase ICP, which was measured by the probe and transmitted to a nearby receiver. The system provided robust and consistent ICP waveforms, was well tolerated, and was stable over time. ICP was elevated to approximately 30 mmHg for one week, after which we assessed changes in optic nerve structure with transmission electron microscopy in cross section and RGC numbers with antibody staining in retinal flat mounts. ICP elevation resulted in optic nerve axonal loss and disorganization, as well as RGC soma loss. We conclude that the controlled manipulation of ICP in active, awake mice is possible, despite their small size. Furthermore, ICP elevation results in visual system phenotypes of optic nerve and RGC degeneration, suggesting that this model can be used to study the impact of ICP on the visual system. Potentially, this model can also be used to study the relationship between ICP and IOP, as well diseases impacted by ICP variation such as glaucoma, idiopathic intracranial hypertension, and the spaceflight-related visual impairment intracranial pressure syndrome. PMID:25912998

  3. Retinal Ganglion Cell Loss is Delayed Following Optic Nerve Crush in NLRP3 Knockout Mice

    PubMed Central

    Puyang, Zhen; Feng, Liang; Chen, Hui; Liang, Peiji; Troy, John B.; Liu, Xiaorong

    2016-01-01

    The NLRP3 inflammasome, a sensor for a variety of pathogen- and host-derived threats, consists of the adaptor ASC (Apoptosis-associated Speck-like protein containing a Caspase Activation and Recruitment Domain (CARD)), pro-caspase-1, and NLRP3 (NOD-Like Receptor family Pyrin domain containing 3). NLRP3-induced neuroinflammation is implicated in the pathogenesis and progression of eye diseases, but it remains unclear whether activation of NLRP3 inflammasome contributes to retinal ganglion cell (RGC) death. Here we examined NLRP3-induced neuroinflammation and RGC survival following partial optic nerve crush (pONC) injury. We showed that NLRP3 was up-regulated in retinal microglial cells following pONC, propagating from the injury site to the optic nerve head and finally the entire retina within one day. Activation of NLRP3-ASC inflammasome led to the up-regulation of caspase-1 and a proinflammatory cytokine, interleukin-1β (IL-1β). In NLRP3 knockout mice, up-regulation of ASC, caspase-1, and IL-1β were all reduced, and, importantly, RGC and axon loss was substantially delayed following pONC injury. The average survival time of RGCs in NLRP3 knockout mice was about one week longer than for control animals. Taken together, our study demonstrated that ablating the NLRP3 gene significantly reduced neuroinflammation and delayed RGC loss after optic nerve crush injury. PMID:26893104

  4. Dendritic Morphology of Caudal Periaqueductal Gray Projecting Retinal Ganglion Cells in Mongolian Gerbil (Meriones unguiculatus)

    PubMed Central

    Ren, Chaoran; Pu, Mingliang; Cui, Qi; So, Kwok-Fai

    2014-01-01

    In this study we investigated the morphological features of the caudal periaqueductal gray (cPAG)-projecting retinal ganglion cells (RGCs) in Mongolian gerbils using retrograde labeling, in vitro intracellular injection, confocal microscopy and three-dimensional reconstruction approaches. cPAG-projecting RGCs exhibit small somata (10–17 µm) and irregular dendritic fields (201–298 µm). Sizes of somata and dendritic fields do not show obvious variation at different distance from the optic disk (eccentricity). Dendrites are moderately branched. Morphological analysis (n = 23) reveals that cPAG-projecting RGCs ramified in sublamina a and b in the inner plexiform layer. These cells exhibit different stratification patterns based on the thickness of dendritic bands in sublaminas a and b: majority of analyzed cells (16 out of 23) have two bands of arborizations share similar thickness. The rest of analyzed cells (7 out of 23) exhibit thinner band in sublamina a than in sublamina b. Together, the present study suggests that cPAG of Mongolian gerbil could receive direct retinal inputs from two types of bistratified RGCs. Furthermore, a small subset of melanopsin-expressing RGCs (total 41 in 6 animals) is shown to innervate the rostral PAG (rPAG). Functional characteristics of these non-visual center projecting RGCs remain to be determined. PMID:25054882

  5. Trimetazidine protects retinal ganglion cells from acute glaucoma via the Nrf2/Ho-1 pathway.

    PubMed

    Wan, Peixing; Su, Wenru; Zhang, Yingying; Li, Zhidong; Deng, Caibin; Zhuo, Yehong

    2017-09-15

    Acute glaucoma is one of the leading causes of irreversible vision impairment characterized by the rapid elevation of intraocular pressure (IOP) and consequent retinal ganglion cell (RGC) death. Oxidative stress and neuroinflammation have been considered critical for the pathogenesis of RGC death in acute glaucoma. Trimetazidine (TMZ), an anti-ischemic drug, possesses antioxidative and anti-inflammatory properties, contributing to its therapeutic potential in tissue damage. However, the role of TMZ in acute glaucoma and the underlying molecular mechanisms remain elusive. Here, we report that treatment with TMZ significantly attenuated retinal damage and RGC death in mice with acute glaucoma, with a significant decrease in reactive oxygen species (ROS) and inflammatory cytokine production in the retina. Furthermore, TMZ treatment directly decreased ROS production and rebalanced the intracellular redox state, thus contributing to the survival of RGCs in vitro TMZ treatment also reduced the production of inflammatory cytokines in vitro Mechanistically, the TMZ-mediated inhibition of apoptosis and inflammatory cytokine production in RGCs occurred via the regulation of the nuclear factor erythroid 2-related factor 2/heme oxygenase 1/caspase-8 pathway. Moreover, the TMZ-mediated neuroprotection in acute glaucoma was abrogated when an HO-1 inhibitor, SnPP, was used. Our findings identify potential mechanisms of RGC apoptosis and propose a novel therapeutic agent, TMZ, which exerts a precise neuroprotective effect against acute glaucoma. © 2017 The Author(s).

  6. Imaging of single retinal ganglion cell with differential interference contrast microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Oh, Juyeong; Kim, Yu Jeong; Kim, Chul-Ki; Lee, Taik Jin; Seo, Mina; Lee, Seok; Woo, Deok Ha; Jun, Seong Chan; Park, Ki-Ho; Kim, Seok Hwan; Kim, Jae Hun

    2017-02-01

    Glaucoma is a progressive optic neuropathy, characterized by the selective loss of retinal ganglion cells (RGCs). Therefore, monitoring the change of number or morphology of RGC is essential for the early detection as well as investigation of pathophysiology of glaucoma. Since RGC layer is transparent and hyporeflective, the direct optical visualization of RGCs has not been successful so far. Therefore, glaucoma evaluation mostly depends on indirect diagnostic methods such as the evaluation of optic disc morphology or retinal nerve fiber layer thickness measurement by optical coherence tomography. We have previously demonstrated single photoreceptor cell imaging with differential interference contrast (DIC) microscopy. Herein, we successfully visualized single RGC using DIC microscopy. Since RGC layer is much less reflective than photoreceptor layer, various techniques including the control of light wavelength and bandwidth using a tunable band pass filter were adopted to reduce the chromatic aberration in z-axis for higher and clearer resolution. To verify that the imaged cells were the RGCs, the flat-mounted retina of Sprague-Dawley rat, in which the RGCs were retrogradely labeled with fluorescence, was observed by both fluorescence and DIC microscopies for direct comparison. We have confirmed that the cell images obtained by fluorescence microscopy were perfectly matched with cell images by DIC microscopy. As conclusion, we have visualized single RGC with DIC microscopy, and confirmed with fluorescence microscopy.

  7. The retinal projectome reveals brain-area-specific visual representations generated by ganglion cell diversity.

    PubMed

    Robles, Estuardo; Laurell, Eva; Baier, Herwig

    2014-09-22

    Visual information is transmitted to the vertebrate brain exclusively via the axons of retinal ganglion cells (RGCs). The functional diversity of RGCs generates multiple representations of the visual environment that are transmitted to several brain areas. However, in no vertebrate species has a complete wiring diagram of RGC axonal projections been constructed. We employed sparse genetic labeling and in vivo imaging of the larval zebrafish to generate a cellular-resolution map of projections from the retina to the brain. Our data define 20 stereotyped axonal projection patterns, the majority of which innervate multiple brain areas. Morphometric analysis of pre- and postsynaptic RGC structure revealed more than 50 structural RGC types with unique combinations of dendritic and axonal morphologies, exceeding current estimates of RGC diversity in vertebrates. These single-cell projection mapping data indicate that specific projection patterns are nonuniformly specified in the retina to generate retinotopically biased visual maps throughout the brain. The retinal projectome also successfully predicted a functional subdivision of the pretectum. Our data indicate that RGC projection patterns are precisely coordinated to generate brain-area-specific visual representations originating from RGCs with distinct dendritic morphologies and topographic distributions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. A morphological classification of retinal ganglion cells in the Japanese catshark Scyliorhinus torazame.

    PubMed

    Muguruma, Kaori; Stell, William K; Yamamoto, Naoyuki

    2014-01-01

    Retinal ganglion cells (GCs) in the Japanese catshark Scyliorhinus torazame were labeled retrogradely with biotinylated dextran amine (BDA3000). First the labeled cells were classified into 5 morphological types (types I-III: small GCs; types IV and V: large GCs) according to the size of the soma and the dendritic arborization pattern as seen in retinal wholemounts. Type I cells were stellate, with dendrites radiating in different directions. Type II cells had bipolar dendritic trees, with 2 primary dendrites extending in opposite directions. Type III cells had a single thick primary dendrite. Type IV cells were stellate, with dendrites covering a large area centered on the cell body. Type V cells were asymmetric, with most dendrites extending opposite to the axon as a large, fan-shaped dendritic field. Subsequently a wholemount was cross-sectioned, and we classified cells further into multiple subtypes according to the level of dendritic arborization within the inner plexiform layer. The present results suggest the existence of many types of GCs in elasmobranchs in addition to the 3 types of large GCs that have been characterized previously. Some of the newly described GC subtypes in the catshark retina appear to be similar to some of those reported in actinopterygians.

  9. An invertebrate-like phototransduction cascade mediates light detection in the chicken retinal ganglion cells.

    PubMed

    Contin, Maria Ana; Verra, Daniela M; Guido, Mario E

    2006-12-01

    Prebilaterian animals perceived ambient light through nonvisual rhabdomeric photoreceptors (RPs), which evolved as support of the chordate visual system. In vertebrates, the identity of nonvisual photoreceptors and the phototransduction cascade involved in nonimage forming tasks remain uncertain. We investigated whether chicken retinal ganglion cells (RGCs) could be nonvisual photoreceptors and the nature of the photocascade involved. We found that primary cultures of chicken embryonic RGCs express such RP markers as transcription factors Pax6 and Brn3, photopigment melanopsin, and G-protein q but not markers for ciliary photoreceptors (alpha-transducin and Crx). To investigate the photoreceptive capability of RGCs, we assessed the direct effect of light on 3H-melatonin synthesis in RGC cultures synchronized to 12:12 h light-dark cycles. In constant dark, RGCs displayed a daily variation in 3H-melatonin levels peaking at subjective day, which was significantly inhibited by light. This light effect was further increased by the chromophore all-trans-retinal and suppressed by specific inhibitors of the invertebrate photocascade involving phosphoinositide hydrolysis (100 microM neomycin; 5 microM U73122) and Ca2+ mobilization (10 mM BAPTA; 1 mM lanthanum). The results demonstrate that chicken RGCs are intrinsically photosensitive RPs operating via an invertebrate-like phototransduction cascade, which may be responsible for early detection of light before vision occurs.

  10. A general principle governs vision-dependent dendritic patterning of retinal ganglion cells.

    PubMed

    Xu, Hong-Ping; Sun, Jin Hao; Tian, Ning

    2014-10-15

    Dendritic arbors of retinal ganglion cells (RGCs) collect information over a certain area of the visual scene. The coverage territory and the arbor density of dendrites determine what fraction of the visual field is sampled by a single cell and at what resolution. However, it is not clear whether visual stimulation is required for the establishment of branching patterns of RGCs, and whether a general principle directs the dendritic patterning of diverse RGCs. By analyzing the geometric structures of RGC dendrites, we found that dendritic arbors of RGCs underwent a substantial spatial rearrangement after eye-opening. Light deprivation blocked both the dendritic growth and the branch patterning, suggesting that visual stimulation is required for the acquisition of specific branching patterns of RGCs. We further showed that vision-dependent dendritic growth and arbor refinement occurred mainly in the middle portion of the dendritic tree. This nonproportional growth and selective refinement suggest that the late-stage dendritic development of RGCs is not a passive stretching with the growth of eyes, but rather an active process of selective growth/elimination of dendritic arbors of RGCs driven by visual activity. Finally, our data showed that there was a power law relationship between the coverage territory and dendritic arbor density of RGCs on a cell-by-cell basis. RGCs were systematically less dense when they cover larger territories regardless of their cell type, retinal location, or developmental stage. These results suggest that a general structural design principle directs the vision-dependent patterning of RGC dendrites.

  11. Qualitative and quantitative ultrastructural observations on retinal ganglion cell layer of rat after intraorbital optic nerve crush.

    PubMed

    Barron, K D; Dentinger, M P; Krohel, G; Easton, S K; Mankes, R

    1986-06-01

    Rat retinal ganglion cell layer (GCL) was examined ultrastructurally 1-180 days after intraorbital crushing of one optic nerve. It was confirmed quantitatively that axotomized ganglion cells lost cisternal membranes of the rough endoplasmic reticulum (RER) and showed disintegration of Nissl bodies and ribosomal rosettes 3 days postoperatively. Between 60 and 180 days after neurotomy there was partial reversion of the RER towards normal. At postoperative intervals of 14-60 days, chromatin aggregation became conspicuous and some nuclei were prominently furrowed and contained electron-dense inclusions. Concurrently, profiles of dead ganglion cells were encountered. Mean mitochondrial area increased in axotomized neurons but mitochondrial density declined, while the Golgi apparatus, lamellar specializations of the RER and the size of nuclei did not change significantly. Cytoplasmic atrophy was profound, however. Small nerve cells of the GCL appeared morphologically distinct from ganglion cells and did not undergo appreciable alteration. A decline in neuronal density, approximating 35%, occurred between the third and seventh postoperative day and progressed slowly thereafter. Neuronal density was 32% of normal 180 days postoperatively. A temporary increase in glial density 3-28 days after operation was due to microglial hyperplasia. Müller cell and astrocytic processes hypertrophied, infiltrated nerve fibre bundles, and surrounded and intruded into neuronal somata. Bundles of unmyelinated small axons, invested by astrocytes and basal lamina, were present within the necrotic cavity of the lesioned nerve 28-90 days postoperatively and had cytologic features of regenerative axonal sprouts. We conclude that intraorbital optic nerve crush is followed by a noteworthy degree of regenerative axonal sprouting which occurs and persists against a background of slow but relentless decline in the retinal ganglion cell population. This slow decline follows a rapidly-sustained loss

  12. Optimal voltage stimulation parameters for network-mediated responses in wild type and rd10 mouse retinal ganglion cells.

    PubMed

    Jalligampala, Archana; Sekhar, Sudarshan; Zrenner, Eberhart; Rathbun, Daniel L

    2017-04-01

    To further improve the quality of visual percepts elicited by microelectronic retinal prosthetics, substantial efforts have been made to understand how retinal neurons respond to electrical stimulation. It is generally assumed that a sufficiently strong stimulus will recruit most retinal neurons. However, recent evidence has shown that the responses of some retinal neurons decrease with excessively strong stimuli (a non-monotonic response function). Therefore, it is necessary to identify stimuli that can be used to activate the majority of retinal neurons even when such non-monotonic cells are part of the neuronal population. Taking these non-monotonic responses into consideration, we establish the optimal voltage stimulation parameters (amplitude, duration, and polarity) for epiretinal stimulation of network-mediated (indirect) ganglion cell responses. We recorded responses from 3958 mouse retinal ganglion cells (RGCs) in both healthy (wild type, WT) and a degenerating (rd10) mouse model of retinitis pigmentosa-using flat-mounted retina on a microelectrode array. Rectangular monophasic voltage-controlled pulses were presented with varying voltage, duration, and polarity. We found that in 4-5 weeks old rd10 mice the RGC thresholds were comparable to those of WT. There was a marked response variability among mouse RGCs. To account for this variability, we interpolated the percentage of RGCs activated at each point in the voltage-polarity-duration stimulus space, thus identifying the optimal voltage-controlled pulse (-2.4 V, 0.88 ms). The identified optimal voltage pulse can activate at least 65% of potentially responsive RGCs in both mouse strains. Furthermore, this pulse is well within the range of stimuli demonstrated to be safe and effective for retinal implant patients. Such optimized stimuli and the underlying method used to identify them support a high yield of responsive RGCs and will serve as an effective guideline for future in vitro investigations of

  13. Optimal voltage stimulation parameters for network-mediated responses in wild type and rd10 mouse retinal ganglion cells

    NASA Astrophysics Data System (ADS)

    Jalligampala, Archana; Sekhar, Sudarshan; Zrenner, Eberhart; Rathbun, Daniel L.

    2017-04-01

    To further improve the quality of visual percepts elicited by microelectronic retinal prosthetics, substantial efforts have been made to understand how retinal neurons respond to electrical stimulation. It is generally assumed that a sufficiently strong stimulus will recruit most retinal neurons. However, recent evidence has shown that the responses of some retinal neurons decrease with excessively strong stimuli (a non-monotonic response function). Therefore, it is necessary to identify stimuli that can be used to activate the majority of retinal neurons even when such non-monotonic cells are part of the neuronal population. Taking these non-monotonic responses into consideration, we establish the optimal voltage stimulation parameters (amplitude, duration, and polarity) for epiretinal stimulation of network-mediated (indirect) ganglion cell responses. We recorded responses from 3958 mouse retinal ganglion cells (RGCs) in both healthy (wild type, WT) and a degenerating (rd10) mouse model of retinitis pigmentosa—using flat-mounted retina on a microelectrode array. Rectangular monophasic voltage-controlled pulses were presented with varying voltage, duration, and polarity. We found that in 4–5 weeks old rd10 mice the RGC thresholds were comparable to those of WT. There was a marked response variability among mouse RGCs. To account for this variability, we interpolated the percentage of RGCs activated at each point in the voltage-polarity-duration stimulus space, thus identifying the optimal voltage-controlled pulse (‑2.4 V, 0.88 ms). The identified optimal voltage pulse can activate at least 65% of potentially responsive RGCs in both mouse strains. Furthermore, this pulse is well within the range of stimuli demonstrated to be safe and effective for retinal implant patients. Such optimized stimuli and the underlying method used to identify them support a high yield of responsive RGCs and will serve as an effective guideline for future in vitro investigations

  14. Retinal Ganglion Cell Count Estimates Associated with Early Development of Visual Field Defects in Glaucoma

    PubMed Central

    Medeiros, Felipe A.; Lisboa, Renato; Weinreb, Robert N.; Liebmann, Jeffrey M.; Girkin, Christopher; Zangwill, Linda M.

    2013-01-01

    Purpose To estimate retinal ganglion cell (RGC) losses associated with the earliest development of visual field defects in glaucoma. Design Observational cohort study. Participants The study group included 53 eyes of 53 patients suspected of having glaucoma who were followed as part of the Diagnostic Innovations in Glaucoma (DIGS) study. These eyes had normal standard automated perimetry (SAP) visual fields at baseline and developed repeatable (3 consecutive) abnormal tests during a median follow-up of 6.7 years. An age-matched control group of 124 eyes of 124 healthy subjects recruited from the general population was included. Methods Estimates of RGC counts were obtained using a previously published model which combines estimates of RGC numbers from SAP sensitivity thresholds and retinal nerve fiber layer (RNFL) thickness measurements with spectral domain optical coherence tomography (SDOCT). For eyes converting to glaucoma, estimates of RGC counts were obtained at the time (within ± 3 months) of the first abnormal visual field, representing the time of earliest detection of visual field losses. Main Outcome Measures Estimates of RGC counts in eyes converting to glaucoma versus healthy eyes. Results The average RGC count estimate in the eyes with early visual field defects was 652057 ± 115829 cells, which was significantly lower than the average of 910584 ± 142412 cells found in healthy eyes (P<0.001). Compared to the average number of RGCs in the healthy group, glaucoma eyes had an average RGC loss of 28.4%, ranging from 6% to 57%, at the time of the earliest visual field defect on SAP. RGC counts performed significantly better than the SDOCT average RNFL thickness parameter in discriminating glaucomatous from healthy eyes with ROC curve areas of 0.95 ± 0.02 versus 0.88 ±0.03, respectively (P=0.001). Conclusion Glaucomatous eyes with the earliest detectable visual field loss on automated perimetry may already show substantial loss of retinal ganglion cells

  15. Early macular retinal ganglion cell loss in dominant optic atrophy: genotype-phenotype correlation.

    PubMed

    Barboni, Piero; Savini, Giacomo; Cascavilla, Maria Lucia; Caporali, Leonardo; Milesi, Jacopo; Borrelli, Enrico; La Morgia, Chiara; Valentino, Maria Lucia; Triolo, Giacinto; Lembo, Andrea; Carta, Arturo; De Negri, Annamaria; Sadun, Federico; Rizzo, Giovanni; Parisi, Vincenzo; Pierro, Luisa; Bianchi Marzoli, Stefania; Zeviani, Massimo; Sadun, Alfredo A; Bandello, Francesco; Carelli, Valerio

    2014-09-01

    To assess the peripapillary retinal nerve fiber and macular retinal ganglion cell (RGC) loss in patients with dominant optic atrophy (DOA) stratified by OPA1 mutation type. Cross-sectional study. We studied 39 patients from 28 pedigrees with DOA harboring heterozygous mutations in the OPA1 gene along with 45 age-matched healthy subjects. The retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) of patients with DOA were evaluated by optical coherence tomography (OCT) and compared to those of controls. Patients' eyes were divided into 4 groups based on increasing severity of visual loss (DOA1 to DOA4) and were stratified by OPA1 mutation type. The average thicknesses of the RNFL and GC-IPL were smaller in patients with DOA than in healthy controls (P < 0.0001). RNFL analysis showed a significant reduction of the average, superior and inferior quadrants thicknesses in the DOA4 group compared to the DOA1 group (P = 0.001, P = 0.002 and P = 0.001, respectively). GC-IPL analysis showed a significant thinning in the superotemporal and superior sectors in the patients with DOA2 compared to those with DOA1 (P = 0.046 and P = 0.04, respectively). Stratifying by mutation type, average, superior and nasal RNFL thinning was significantly more severe in missense mutations and had a presumed dominant-negative effect compared to mutations causing haploinsufficiency. The present study demonstrates that in DOA, loss of macular RGCs is the earliest pathologic event, better reflected by GC-IPL measurements, whereas RNFL thickness is a measure of spared axons in late stages of the disease. Thus, mild cases (DOA2) show significant macular RGC loss as opposed to substantial maintenance of RNFL thickness, which is significantly decreased only in severe cases (DOA4). A clear genotype/phenotype correlation emerged, stratifying OCT measures by OPA1 mutation type, missense mutations being the most severe. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Genetically Identified Suppressed-by-Contrast Retinal Ganglion Cells Reliably Signal Self-Generated Visual Stimuli

    PubMed Central

    Tien, Nai-Wen; Pearson, James T.; Heller, Charles R.; Demas, Jay

    2015-01-01

    Spike trains of retinal ganglion cells (RGCs) are the sole source of visual information to the brain; and understanding how the ∼20 RGC types in mammalian retinae respond to diverse visual features and events is fundamental to understanding vision. Suppressed-by-contrast (SbC) RGCs stand apart from all other RGC types in that they reduce rather than increase firing rates in response to light increments (ON) and decrements (OFF). Here, we genetically identify and morphologically characterize SbC-RGCs in mice, and target them for patch-clamp recordings under two-photon guidance. We find that strong ON inhibition (glycine > GABA) outweighs weak ON excitation, and that inhibition (glycine > GABA) coincides with decreases in excitation at light OFF. These input patterns explain the suppressive spike responses of SbC-RGCs, which are observed in dim and bright light conditions. Inhibition to SbC-RGC is driven by rectified receptive field subunits, leading us to hypothesize that SbC-RGCs could signal pattern-independent changes in the retinal image. Indeed, we find that shifts of random textures matching saccade-like eye movements in mice elicit robust inhibitory inputs and suppress spiking of SbC-RGCs over a wide range of texture contrasts and spatial frequencies. Similarly, stimuli based on kinematic analyses of mouse blinking consistently suppress SbC-RGC spiking. Receiver operating characteristics show that SbC-RGCs are reliable indicators of self-generated visual stimuli that may contribute to central processing of blinks and saccades. SIGNIFICANCE STATEMENT This study genetically identifies and morphologically characterizes suppressed-by-contrast retinal ganglion cells (SbC-RGCs) in mice. Targeted patch-clamp recordings from SbC-RGCs under two-photon guidance elucidate the synaptic mechanisms mediating spike suppression to contrast steps, and reveal that SbC-RGCs respond reliably to stimuli mimicking saccade-like eye movements and blinks. The similarity of

  17. Correspondence between visual and electrical input filters of ON and OFF mouse retinal ganglion cells

    NASA Astrophysics Data System (ADS)

    Sekhar, S.; Jalligampala, A.; Zrenner, E.; Rathbun, D. L.

    2017-08-01

    Objective. Over the past two decades retinal prostheses have made major strides in restoring functional vision to patients blinded by diseases such as retinitis pigmentosa. Presently, implants use single pulses to activate the retina. Though this stimulation paradigm has proved beneficial to patients, an unresolved problem is the inability to selectively stimulate the on and off visual pathways. To this end our goal was to test, using white noise, voltage-controlled, cathodic, monophasic pulse stimulation, whether different retinal ganglion cell (RGC) types in the wild type retina have different electrical input filters. This is an important precursor to addressing pathway-selective stimulation. Approach. Using full-field visual flash and electrical and visual Gaussian noise stimulation, combined with the technique of spike-triggered averaging (STA), we calculate the electrical and visual input filters for different types of RGCs (classified as on, off or on-off based on their response to the flash stimuli). Main results. Examining the STAs, we found that the spiking activity of on cells during electrical stimulation correlates with a decrease in the voltage magnitude preceding a spike, while the spiking activity of off cells correlates with an increase in the voltage preceding a spike. No electrical preference was found for on-off cells. Comparing STAs of wild type and rd10 mice revealed narrower electrical STA deflections with shorter latencies in rd10. Significance. This study is the first comparison of visual cell types and their corresponding temporal electrical input filters in the retina. The altered input filters in degenerated rd10 retinas are consistent with photoreceptor stimulation underlying visual type-specific electrical STA shapes in wild type retina. It is therefore conceivable that existing implants could target partially degenerated photoreceptors that have only lost their outer segments, but not somas, to selectively activate the on and off

  18. A dedicated circuit links direction-selective retinal ganglion cells to the primary visual cortex.

    PubMed

    Cruz-Martín, Alberto; El-Danaf, Rana N; Osakada, Fumitaka; Sriram, Balaji; Dhande, Onkar S; Nguyen, Phong L; Callaway, Edward M; Ghosh, Anirvan; Huberman, Andrew D

    2014-03-20

    How specific features in the environment are represented within the brain is an important unanswered question in neuroscience. A subset of retinal neurons, called direction-selective ganglion cells (DSGCs), are specialized for detecting motion along specific axes of the visual field. Despite extensive study of the retinal circuitry that endows DSGCs with their unique tuning properties, their downstream circuitry in the brain and thus their contribution to visual processing has remained unclear. In mice, several different types of DSGCs connect to the dorsal lateral geniculate nucleus (dLGN), the visual thalamic structure that harbours cortical relay neurons. Whether direction-selective information computed at the level of the retina is routed to cortical circuits and integrated with other visual channels, however, is unknown. Here we show that there is a di-synaptic circuit linking DSGCs with the superficial layers of the primary visual cortex (V1) by using viral trans-synaptic circuit mapping and functional imaging of visually driven calcium signals in thalamocortical axons. This circuit pools information from several types of DSGCs, converges in a specialized subdivision of the dLGN, and delivers direction-tuned and orientation-tuned signals to superficial V1. Notably, this circuit is anatomically segregated from the retino-geniculo-cortical pathway carrying non-direction-tuned visual information to deeper layers of V1, such as layer 4. Thus, the mouse harbours several functionally specialized, parallel retino-geniculo-cortical pathways, one of which originates with retinal DSGCs and delivers direction- and orientation-tuned information specifically to the superficial layers of the primary visual cortex. These data provide evidence that direction and orientation selectivity of some V1 neurons may be influenced by the activation of DSGCs.

  19. Differential responses to high-frequency electrical stimulation in ON and OFF retinal ganglion cells

    NASA Astrophysics Data System (ADS)

    Twyford, Perry; Cai, Changsi; Fried, Shelley

    2014-04-01

    Objective. The field of retinal prosthetics for artificial vision has advanced considerably in recent years, however clinical outcomes remain inconsistent. The performance of retinal prostheses is likely limited by the inability of electrical stimuli to preferentially activate different types of retinal ganglion cell (RGC). Approach. Here we examine the response of rabbit RGCs to high-frequency stimulation, using biphasic pulses applied at 2000 pulses per second. Responses were recorded using cell-attached patch clamp methods, and stimulation was applied epiretinally via a small cone electrode. Main results. When prolonged stimulus trains were applied to OFF-brisk transient (BT) RGCs, the cells exhibited a non-monotonic relationship between response strength and stimulus amplitude; this response pattern was different from those elicited previously by other electrical stimuli. When the amplitude of the stimulus was modulated transiently from a non-zero baseline amplitude, ON-BT and OFF-BT cells exhibited different activity patterns: ON cells showed an increase in activity while OFF cells exhibited a decrease in activity. Using a different envelope to modulate the amplitude of the stimulus, we observed the opposite effect: ON cells exhibited a decrease in activity while OFF cells show an increase in activity. Significance. As ON and OFF RGCs often exhibit opposing activity patterns in response to light stimulation, this work suggests that high-frequency electrical stimulation of RGCs may be able to elicit responses that are more physiological than traditional pulsatile stimuli. Additionally, the prospect of an electrical stimulus capable of cell-type specific selective activation has broad applications throughout the fields of neural stimulation and neuroprostheses.

  20. Reprogramming amacrine and photoreceptor progenitors into retinal ganglion cells by replacing Neurod1 with Atoh7.

    PubMed

    Mao, Chai-An; Cho, Jang-Hyeon; Wang, Jing; Gao, Zhiguang; Pan, Ping; Tsai, Wen-Wei; Frishman, Laura J; Klein, William H

    2013-02-01

    The specification of the seven retinal cell types from a common pool of retina progenitor cells (RPCs) involves complex interactions between the intrinsic program and the environment. The proneural basic helix-loop-helix (bHLH) transcriptional regulators are key components for the intrinsic programming of RPCs and are essential for the formation of the diverse retinal cell types. However, the extent to which an RPC can re-adjust its inherent program and the mechanisms through which the expression of a particular bHLH factor influences RPC fate is unclear. Previously, we have shown that Neurod1 inserted into the Atoh7 locus activates the retinal ganglion cell (RGC) program in Atoh7-expressing RPCs but not in Neurod1-expressing RPCs, suggesting that Atoh7-expressing RPCs are not able to adopt the cell fate determined by Neurod1, but rather are pre-programmed to produce RGCs. Here, we show that Neurod1-expressing RPCs, which are destined to produce amacrine and photoreceptor cells, can be re-programmed into RGCs when Atoh7 is inserted into the Neurod1 locus. These results suggest that Atoh7 acts dominantly to convert a RPC subpopulation not destined for an RGC fate to adopt that fate. Thus, Atoh7-expressing and Neurod1-expressing RPCs are intrinsically different in their behavior. Additionally, ChIP-Seq analysis identified an Atoh7-dependent enhancer within the intronic region of Nrxn3. The enhancer recognized and used Atoh7 in the developing retina to regulate expression of Nrxn3, but could be forced to use Neurod1 when placed in a different regulatory context. The results indicate that Atoh7 and Neurod1 activate distinct sets of genes in vivo, despite their common DNA-binding element.

  1. Transplantation of Human Neural Progenitor Cells Expressing IGF-1 Enhances Retinal Ganglion Cell Survival

    PubMed Central

    Guo, Caiwei; Sun, Yu; Liao, Tiffany; Beattie, Ursula; López, Francisco J.; Chen, Dong Feng; Lashkari, Kameran

    2015-01-01

    We have previously characterized human neuronal progenitor cells (hNP) that can adopt a retinal ganglion cell (RGC)-like morphology within the RGC and nerve fiber layers of the retina. In an effort to determine whether hNPs could be used a candidate cells for targeted delivery of neurotrophic factors (NTFs), we evaluated whether hNPs transfected with an vector that expresses IGF-1 in the form of a fusion protein with tdTomato (TD), would increase RGC survival in vitro and confer neuroprotective effects in a mouse model of glaucoma. RGCs co-cultured with hNPIGF-TD cells displayed enhanced survival, and increased neurite extension and branching as compared to hNPTD or untransfected hNP cells. Application of various IGF-1 signaling blockers or IGF-1 receptor antagonists abrogated these effects. In vivo, using a model of glaucoma we showed that IOP elevation led to reductions in retinal RGC count. In this model, evaluation of retinal flatmounts and optic nerve cross sections indicated that only hNPIGF-TD cells effectively reduced RGC death and showed a trend to improve optic nerve axonal loss. RT-PCR analysis of retina lysates over time showed that the neurotrophic effects of IGF-1 were also attributed to down-regulation of inflammatory and to some extent, angiogenic pathways. This study shows that neuronal progenitor cells that hone into the RGC and nerve fiber layers may be used as vehicles for local production and delivery of a desired NTF. Transplantation of hNPIGF-TD cells improves RGC survival in vitro and protects against RGC loss in a rodent model of glaucoma. Our findings have provided experimental evidence and form the basis for applying cell-based strategies for local delivery of NTFs into the retina. Application of cell-based delivery may be extended to other disease conditions beyond glaucoma. PMID:25923430

  2. Protective effects of triptolide on retinal ganglion cells in a rat model of chronic glaucoma

    PubMed Central

    Yang, Fan; Wang, Dongmei; Wu, Lingling; Li, Ying

    2015-01-01

    Purpose To study the effects of triptolide, a Chinese herb extract, on retinal ganglion cells (RGCs) in a rat model of chronic glaucoma. Methods Eighty Wistar rats were randomly divided into triptolide group (n=40) and normal saline (NS) group (n=40). Angle photocoagulation was used to establish the model of glaucoma, with right eye as laser treated eye and left eye as control eye. Triptolide group received triptolide intraperitoneally daily, while NS group received NS. Intraocular pressure (IOP), anti-CD11b immunofluorescent stain in retina and optic nerve, RGCs count with Nissel stain and microglia count with anti-CD11b immunofluorescence stain in retina flat mounts, retinal tumor necrosis factor (TNF)-α mRNA detection by reverse transcription–polymerase chain reaction, and double immunofluorescent labeling with anti-TNF-α and anti-CD11b in retinal frozen section were performed. Results Mean IOP of the laser treated eyes significantly increased 3 weeks after photocoagulation (P<0.05), with no statistical difference between the two groups (P>0.05). RGCs survival in the laser treated eyes was significantly improved in the triptolide group than the NS group (P<0.05). Microglia count in superficial retina of the laser treated eyes was significantly less in the triptolide group (30.40±4.90) than the NS group (35.06±7.59) (P<0.05). TNF-α mRNA expression in the retina of the laser treated eyes in the triptolide group decreased by 60% compared with that in the NS group (P<0.01). The double immunofluorescent labeling showed that TNF-α was mainly distributed around the microglia. Conclusion Triptolide improved RGCs survival in this rat model of chronic glaucoma, which did not depend on IOP decrease but might be exerted by inhibiting microglia activities and reducing TNF-α secretion. PMID:26604697

  3. Effects of p-xylene inhalation on axonal transport in the rat retinal ganglion cells

    SciTech Connect

    Padilla, S.S.; Lyerly, D.P. )

    1989-12-01

    Although the solvent xylene is suspected of producing nervous system dysfunction in animals and humans, little is known regarding the neurochemical consequences of xylene inhalation. The intent of this study was to determine the effect of intermittent, acute, and subchronic p-xylene exposure on the axonal transport of proteins and glycoproteins within the rat retinofugal tract. A number of different exposure regimens were tested ranging from 50 ppm for a single 6-hr exposure to 1600 ppm 6 hr/day, 5 days/week, for a total of 8 exposure days. Immediately following removal from the inhalation chambers rats were injected intraocularly with (35S)methionine and (3H)fucose (to label retinal proteins and glycoproteins, respectively) and the axonal transport of labeled macromolecules to axons (optic nerve and optic tract) and nerve endings (lateral geniculate body and superior colliculus) was examined 20 hr after precursor injection. Only relatively severe exposure regimens (i.e., 800 or 1600 ppm 6 hr/day, 5 days/week, for 1.5 weeks) produced significant reductions in axonal transport; there was a moderate reduction in the axonal transport of 35S-labeled proteins in the 800-ppm-treated group which was more widespread in the 1600 ppm-treated group. Transport of 3H-labeled glycoproteins was less affected. Assessment of retinal metabolism immediately after isotope injection indicated that the rate of precursor uptake was not reduced in either treatment group. Furthermore, rapid transport was still substantially reduced in animals exposed to 1600 ppm p-xylene and allowed a 13-day withdrawal period. These data indicate that p-xylene inhalation decreases rapid axonal transport supplied to the projections of the rat retinal ganglion cells immediately after cessation of inhalation exposure and that this decreased transport is still apparent 13 days after the last exposure.

  4. Pushing the envelope of retinal ganglion cell genesis: context dependent function of Math5 (Atoh7)

    PubMed Central

    Prasov, Lev; Glaser, Tom

    2012-01-01

    The basic-helix-loop helix factor Math5 (Atoh7) is required for retinal ganglion cell (RGC) development. However, only 10% of Math5-expressing cells adopt the RGC fate, and most become photoreceptors. In principle, Math5 may actively bias progenitors towards RGC fate or passively confer competence to respond to instructive factors. To distinguish these mechanisms, we misexpressed Math5 in a wide population of precursors using a Crx BAC or 2.4 kb promoter, and followed cell fates with Cre recombinase. In mice, the Crx cone-rod homeobox gene and Math5 are expressed shortly after cell cycle exit, in temporally distinct, but overlapping populations of neurogenic cells that give rise to 85% and 3% of the adult retina, respectively. The Crx > Math5 transgenes did not stimulate RGC fate or alter the timing of RGC births. Likewise, retroviral Math5 overexpression in retinal explants did not bias progenitors towards the RGC fate or induce cell cycle exit. The Crx>Math5 transgene did reduce the abundance of early-born (E15.5) photoreceptors two-fold, suggesting a limited cell fate shift. Nonetheless, retinal histology was grossly normal, despite widespread persistent Math5 expression. In an RGC-deficient (Math5 knockout) environment, Crx>Math5 partially rescued RGC and optic nerve development, but the temporal envelope of RGC births was not extended. The number of early-born RGCs (before E13) remained very low, and this was correlated with axon pathfinding defects and cell death. Together, these results suggest that Math5 is not sufficient to stimulate RGC fate. Our findings highlight the robust homeostatic mechanisms, and role of pioneering neurons in RGC development. PMID:22609278

  5. A novel system for the classification of diseased retinal ganglion cells.

    PubMed

    Tribble, James R; Cross, Stephen D; Samsel, Paulina A; Sengpiel, Frank; Morgan, James E

    2014-11-01

    Retinal ganglion cell (RGC) dendritic atrophy is an early feature of many forms of retinal degeneration, providing a challenge to RGC classification. The characterization of these changes is complicated by the possibility that selective labeling of any particular class can confound the estimation of dendritic remodeling. To address this issue we have developed a novel, robust, and quantitative RGC classification based on proximal dendritic features which are resistant to early degeneration. RGCs were labeled through the ballistic delivery of DiO and DiI coated tungsten particles to whole retinal explants of 20 adult Brown Norway rats. RGCs were grouped according to the Sun classification system. A comprehensive set of primary and secondary dendrite features were quantified and a new classification model derived using principal component (PCA) and discriminant analyses, to estimate the likelihood that a cell belonged to any given class. One-hundred and thirty one imaged RGCs were analyzed; according to the Sun classification, 24% (n = 31) were RGCA, 29% (n = 38) RGCB, 32% (n = 42) RGCC, and 15% (n = 20) RGCD. PCA gave a 3 component solution, separating RGCs based on descriptors of soma size and primary dendrite thickness, proximal dendritic field size and dendritic tree asymmetry. The new variables correctly classified 73.3% (n = 74) of RGCs from a training sample and 63.3% (n = 19) from a hold out sample indicating an effective model. Soma and proximal dendritic tree morphological features provide a useful surrogate measurement for the classification of RGCs in disease. While a definitive classification is not possible in every case, the technique provides a useful safeguard against sample bias where the normal criteria for cell classification may not be reliable.

  6. A dedicated circuit links direction-selective retinal ganglion cells to the primary visual cortex

    NASA Astrophysics Data System (ADS)

    Cruz-Martín, Alberto; El-Danaf, Rana N.; Osakada, Fumitaka; Sriram, Balaji; Dhande, Onkar S.; Nguyen, Phong L.; Callaway, Edward M.; Ghosh, Anirvan; Huberman, Andrew D.

    2014-03-01

    How specific features in the environment are represented within the brain is an important unanswered question in neuroscience. A subset of retinal neurons, called direction-selective ganglion cells (DSGCs), are specialized for detecting motion along specific axes of the visual field. Despite extensive study of the retinal circuitry that endows DSGCs with their unique tuning properties, their downstream circuitry in the brain and thus their contribution to visual processing has remained unclear. In mice, several different types of DSGCs connect to the dorsal lateral geniculate nucleus (dLGN), the visual thalamic structure that harbours cortical relay neurons. Whether direction-selective information computed at the level of the retina is routed to cortical circuits and integrated with other visual channels, however, is unknown. Here we show that there is a di-synaptic circuit linking DSGCs with the superficial layers of the primary visual cortex (V1) by using viral trans-synaptic circuit mapping and functional imaging of visually driven calcium signals in thalamocortical axons. This circuit pools information from several types of DSGCs, converges in a specialized subdivision of the dLGN, and delivers direction-tuned and orientation-tuned signals to superficial V1. Notably, this circuit is anatomically segregated from the retino-geniculo-cortical pathway carrying non-direction-tuned visual information to deeper layers of V1, such as layer 4. Thus, the mouse harbours several functionally specialized, parallel retino-geniculo-cortical pathways, one of which originates with retinal DSGCs and delivers direction- and orientation-tuned information specifically to the superficial layers of the primary visual cortex. These data provide evidence that direction and orientation selectivity of some V1 neurons may be influenced by the activation of DSGCs.

  7. ATP- and ACh-induced responses in isolated cat petrosal ganglion neurons.

    PubMed

    Alcayaga, Carmen; Varas, Rodrigo; Valdés, Viviana; Cerpa, Verónica; Arroyo, Jorge; Iturriaga, Rodrigo; Alcayaga, Julio

    2007-02-02

    Chemoreceptor (glomus) cells of the carotid body are synaptically connected to the sensory nerve endings of petrosal ganglion (PG) neurons. In response to natural stimuli, the glomus cells release transmitters, which acting on the nerve terminals of petrosal neurons increases the chemosensory afferent discharge. Among several transmitter molecules present in glomus cells, acetylcholine (ACh) and adenosine 5'-triphosphate (ATP) are considered to act as excitatory transmitter in this synapse. To test if ACh and ATP play a role as excitatory transmitters in the cat CB, we recorded the electrophysiological responses from PG neurons cultured in vitro. Under voltage clamp, ATP induces a concentration-dependent inward current that partially desensitizes during 20-30 s application pulses. The ATP-induced current has a threshold near 100 nM and saturates between 20-50 muM. ACh induces a fast, inactivating inward current, with a threshold between 10-50 muM, and saturates around 1 mM. A large part of the population of PG neurons (60%) respond to both ATP and ACh. Present results support the hypothesis that ACh and ATP act as excitatory transmitters between cat glomus cells and PG neurons.

  8. FGF-2 modulates expression and distribution of GAP-43 in frog retinal ganglion cells after optic nerve injury.

    PubMed

    Soto, Ileana; Marie, Bruno; Baro, Deborah J; Blanco, Rosa E

    2003-08-15

    Basic fibroblast growth factor (bFGF or FGF-2) has been implicated as a trophic factor that promotes survival and neurite outgrowth of neurons. We found previously that application of FGF-2 to the proximal stump of the injured axon increases retinal ganglion cell (RGC) survival. We determine here the effect of FGF-2 on expression of the axonal growth-associated phosphoprotein (GAP)-43 in retinal ganglion cells and tectum of Rana pipiens during regeneration of the optic nerve. In control retinas, GAP-43 protein was found in the optic fiber layer and in optic nerve; mRNA levels were low. After axotomy, mRNA levels increased sevenfold and GAP-43 protein was significantly increased. GAP-43 was localized in retinal axons and in a subset of RGC cell bodies and dendrites. This upregulation of GAP-43 was sustained through the period in which retinal axons reconnect with their target in the tectum. FGF-2 application to the injured nerve, but not to the eyeball, increased GAP-43 mRNA in the retina but decreased GAP-43 protein levels and decreased the number of immunopositive cell bodies. In the tectum, no treatment affected GAP-43 mRNA but FGF-2 application to the axotomized optic nerve increased GAP-43 protein in regenerating retinal projections. We conclude that FGF-2 upregulates the synthesis and alters the distribution of the axonal growth-promoting protein GAP-43, suggesting that it may enhance axonal regrowth.

  9. An AD-related neuroprotector rescues transformed rat retinal ganglion cells from CoCl₂-induced apoptosis.

    PubMed

    Men, Jie; Zhang, Xiaohui; Yang, Yang; Gao, Dianwen

    2012-05-01

    Some ocular diseases characterized by apoptotic death of retinal ganglion cells (RGCs) and Alzheimer's disease (AD) are chronic neurodegenerative disorders and have similarities in neuropathology. Humanin (HN) is known for its ability to suppress neuronal death induced by AD-related insults. In present study, we investigated the neuroprotective effects of HN on hypoxia-induced toxicity in RGC-5 cells. Hypoxia mimetic compound cobalt chloride (CoCl₂) could increase the cell viability loss and apoptosis, whereas HN can significantly attenuate these effects. This finding may provide new therapeutics for the retinal neurodegenerative diseases targeting neuroprotection.

  10. Early nuclear exclusion of the transcription factor max is associated with retinal ganglion cell death independent of caspase activity.

    PubMed

    Petrs-Silva, Hilda; de Freitas, Fabíola G; Linden, Rafael; Chiarini, Luciana B

    2004-02-01

    We examined the behavior of the transcription factor Max during retrograde neuronal degeneration of retinal ganglion cells. Using immunohistochemistry, we found a progressive redistribution of full-length Max from the nucleus to the cytoplasm and dendrites of the ganglion cells following axon damage. Then, the axotomized cells lose all their content of Max, while undergoing nuclear pyknosis and apoptotic cell death. After treatment of retinal explants with either anisomycin or thapsigargin, the rate of nuclear exclusion of Max accompanied the rate of cell death as modulated by either drug. Treatment with a pan-caspase inhibitor abolished both TUNEL staining and immunoreactivity for activated caspase-3, but did not affect the subcellular redistribution of Max immunoreactivity after axotomy. The data show that nuclear exclusion of the transcription factor Max is an early event, which precedes and is independent of the activation of caspases, during apoptotic cell death in the central nervous system.

  11. Epibatidine application in vitro blocks retinal waves without silencing all retinal ganglion cell action potentials in developing retina of the mouse and ferret.

    PubMed

    Sun, Chao; Speer, Colenso M; Wang, Guo-Yong; Chapman, Barbara; Chalupa, Leo M

    2008-12-01

    Epibatidine (EPI), a potent cholinergic agonist, disrupts acetylcholine-dependent spontaneous retinal activity. Early patch-clamp recordings in juvenile ferrets suggested that EPI blocks all retinal ganglion cell (RGC) action potentials when applied to the retina. In contrast, recent experiments on the developing mouse that relied on multielectrode array (MEA) recordings reported that EPI application decorrelates the activity of neighboring RGCs and eliminates retinal waves while preserving the spiking activity of many neurons. The different techniques used in previous studies raise the question of whether EPI has different effects on RGC activity in mouse compared with that in ferret. A resolution of this issue is essential for interpreting the results of developmental studies that relied on EPI to manipulate retinal activity. Our goal was to compare the effects of EPI on the spontaneous discharges of RGCs in mouse and ferret using 60-electrode MEA as well as patch-clamp recordings during the developmental stage when retinal waves are driven by acetylcholine in both species. We found that in both mouse and ferret EPI decorrelates RGC activity and eliminates retinal waves. However, EPI does not block all spontaneous activity in either species. Instead, our whole cell recordings reveal that EPI silences more than half of all RGCs while significantly increasing the activity of the remainder. These results have important implications for interpreting the results of previous studies that relied on this cholinergic agonist to perturb retinal activity.

  12. Pharmacological Inhibition of Caspase-2 Protects Axotomised Retinal Ganglion Cells from Apoptosis in Adult Rats

    PubMed Central

    Vigneswara, Vasanthy; Berry, Martin; Logan, Ann; Ahmed, Zubair

    2012-01-01

    Severing the axons of retinal ganglion cells (RGC) by crushing the optic nerve (ONC) causes the majority of RGC to degenerate and die, primarily by apoptosis. We showed recently that after ONC in adult rats, caspase-2 activation occurred specifically in RGC while no localisation of caspase-3 was observed in ganglion cells but in cells of the inner nuclear layer. We further showed that inhibition of caspase-2 using a single injection of stably modified siRNA to caspase-2 protected almost all RGC from death at 7 days, offering significant protection for up to 1 month after ONC. In the present study, we confirmed that cleaved caspase-2 was localised and activated in RGC (and occasional neurons in the inner nuclear layer), while TUNEL+ RGC were also observed after ONC. We then investigated if suppression of caspase-2 using serial intravitreal injections of the pharmacological inhibitor z-VDVAD-fmk (z-VDVAD) protected RGC from death for 15 days after ONC. Treatment of eyes with z-VDVAD suppressed cleaved caspase-2 activation by >85% at 3–4 days after ONC. Increasing concentrations of z-VDVAD protected greater numbers of RGC from death at 15 days after ONC, up to a maximum of 60% using 4000 ng/ml of z-VDVAD, compared to PBS treated controls. The 15-day treatment with 4000 ng/ml of z-VDVAD after ONC suppressed levels of cleaved caspase-2 but no significant changes in levels of cleaved caspase-3, -6, -7 or -8 were detected. Although suppression of caspase-2 protected 60% of RGC from death, RGC axon regeneration was not promoted. These results suggest that caspase-2 specifically mediates death of RGC after ONC and that suppression of caspase-2 may be a useful therapeutic strategy to enhance RGC survival not only after axotomy but also in diseases where RGC death occurs such as glaucoma and optic neuritis. PMID:23285297

  13. Retinal ganglion cell distribution and spatial resolving power in the Japanese catshark Scyliorhinus torazame.

    PubMed

    Muguruma, Kaori; Takei, Shiro; Yamamoto, Naoyuki

    2013-01-01

    Topographic distribution of retinal ganglion cells (GCs) is linked with the visual capabilities and behavioral ecology of vertebrates. Studies on the distribution of different types of GCs, however, have been conducted in only a few species of elasmobranchs. In the present study, the distribution and peak cell density of GCs, and spatial resolving power (SRP) were examined in the Japanese catshark, Scyliorhinus torazame. Distinct populations of GCs were identified in the ganglion cell layer of S. torazame based on soma size: small and large GCs, which showed different spatial distribution patterns. A horizontal streak of high cell density was recognized in the dorsal retina for small GCs. The highest cell density occurred within the streak, and the peak SRPs of the three fish investigated in the present study were 2.32, 2.64, and 3.01 cycles/deg. In contrast, two spots of high cell density, or areae gigantocellulares, were identified for large GCs, one in the temporal and the other in the nasal retina. The highest cell density occurred in the temporal or nasal area gigantocellularis (SRP: 1.36, 1.55 and 1.83 cycles/deg). This is the first study reporting an elasmobranch species with a horizontal visual streak of small GCs and two areae gigantocellulares. The horizontal streak of small GCs in the dorsal retina, which serves for the inferior visual field, is likely important for food search on the bottom, and the areae gigantocellulares may be important to the detection of prey and/or predators approaching from the front or behind the catshark.

  14. Synaptic pathways that shape the excitatory drive in an OFF retinal ganglion cell.

    PubMed

    Buldyrev, Ilya; Puthussery, Theresa; Taylor, W Rowland

    2012-04-01

    Different types of retinal ganglion cells represent distinct spatiotemporal filters that respond selectively to specific features in the visual input. Much about the circuitry and synaptic mechanisms that underlie such specificity remains to be determined. This study examines how N-methyl-d-aspartate (NMDA) receptor signaling combines with other excitatory and inhibitory mechanisms to shape the output of small-field OFF brisk-sustained ganglion cells (OFF-BSGCs) in the rabbit retina. We used voltage clamp to separately resolve NMDA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and inhibitory inputs elicited by stimulation of the receptive field center. Three converging circuits were identified. First is a direct glutamatergic input, arising from OFF cone bipolar cells (CBCs), which is mediated by synaptic NMDA and AMPA receptors. The NMDA input was saturated at 10% contrast, whereas the AMPA input increased monotonically up to 60% contrast. We propose that NMDA inputs selectively enhance sensitivity to low contrasts. The OFF bipolar cells, mediating this direct excitatory input, express dendritic kainate (KA) receptors, which are resistant to the nonselective AMPA/KA receptor antagonist, 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide disodium salt (NBQX), but are suppressed by a GluK1- and GluK3-selective antagonist, (S)-1-(2-amino-2-carboxyethyl)-3-(2-carboxy-thiophene-3-yl-methyl)-5-methylpyrimidine-2,4-dione (UBP-310). The second circuit entails glycinergic crossover inhibition, arising from ON-CBCs and mediated by AII amacrine cells, which modulate glutamate release from the OFF-CBC terminals. The third circuit also comprises glycinergic crossover inhibition, which is driven by the ON pathway; however, this inhibition impinges directly on the OFF-BSGCs and is mediated by an unknown glycinergic amacrine cell that expresses AMPA but not KA receptors.

  15. Distribution and function of polycystin-2 in mouse retinal ganglion cells

    PubMed Central

    Kaja, Simon; Mafe, Oloruntoyin A.; Parikh, Ruby A.; Kandula, Prasanthi; Reddy, Chanakyaram A.; Gregg, Elaine V.; Xin, Hua; Mitchell, Peter; Grillo, Michael A.; Koulen, Peter

    2011-01-01

    The polycystin family of transient receptor potential (TRP) channels form Ca2+ regulated cation channels with distinct subcellullar localizations and functions. As part of heteromultimeric channels and multi-protein complexes, polycystins control intracellular Ca2+ signals and more generally the translation of extracellular signals and stimuli to intracellular responses. Polycystin-2 channels have been cloned from retina, but their distribution and function in retinal ganglion cells (RGCs) have not yet been established. In the present study, we determined cellular and subcellular localization as well as functional properties of polycystin-2 channels in RGCs. Polycystin-2 expression and distribution in RGCs was assessed by immunohistochemistry on vertical cryostat section of mouse retina as well as primary cultured mouse RGCs, using fluorescence microscopy. Biophysical and pharmacological properties of polycystin-2 channels isolated from primary cultured RGCs were determined using planar lipid bilayer electrophysiology. We detected polycystin-2 immunoreactivity both in the ganglion cell layer as well as in primary cultured RGCs. Subcellular analysis revealed strong cytosolic localization pattern of polycystin-2. Polycystin-2 channel current was Ca2+ activated, had a maximum slope conductance of 114 pS and could be blocked in a dose-dependent manner by increasing concentrations of Mg2+. The cytosolic localization of polycystin-2 in RGCs is in accordance with its function as intracellular Ca2+ release channel. We conclude that polycystin-2 forms functional channels in RGCs, of which biophysical and pharmacological properties are similar to polycystin-2 channels reported for other tissues and organisms. Our data suggest a potential role for polycystin-2 in RGC Ca2+ signaling. PMID:22155264

  16. Axonal Degeneration in Retinal Ganglion Cells Is Associated with a Membrane Polarity-Sensitive Redox Process

    PubMed Central

    Catrinescu, Maria-Magdalena; Binan, Loïc; Costantino, Santiago

    2017-01-01

    Axonal degeneration is a pathophysiological mechanism common to several neurodegenerative diseases. The slow Wallerian degeneration (WldS) mutation, which results in reduced axonal degeneration in the central and peripheral nervous systems, has provided insight into a redox-dependent mechanism by which axons undergo self-destruction. We studied early molecular events in axonal degeneration with single-axon laser axotomy and time-lapse imaging, monitoring the initial changes in transected axons of purified retinal ganglion cells (RGCs) from wild-type and WldS rat retinas using a polarity-sensitive annexin-based biosensor (annexin B12-Cys101,Cys260-N,N′-dimethyl-N-(iodoacetyl)-N′-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) ethylenediamine). Transected axons demonstrated a rapid and progressive change in membrane phospholipid polarity, manifested as phosphatidylserine externalization, which was significantly delayed and propagated more slowly in axotomized WldS RGCs compared with wild-type axons. Delivery of bis(3-propionic acid methyl ester)phenylphosphine borane complex, a cell-permeable intracellular disulfide-reducing drug, slowed the onset and velocity of phosphatidylserine externalization in wild-type axons significantly, replicating the WldS phenotype, whereas extracellular redox modulation reversed the WldS phenotype. These findings are consistent with an intra-axonal redox mechanism for axonal degeneration associated with the initiation and propagation of phosphatidylserine externalization after axotomy. SIGNIFICANCE STATEMENT Axonal degeneration is a neuronal process independent of somal apoptosis, the propagation of which is unclear. We combined single-cell laser axotomy with time-lapse imaging to study the dynamics of phosphatidylserine externalization immediately after axonal injury in purified retinal ganglion cells. The extension of phosphatidylserine externalization was slowed and delayed in Wallerian degeneration slow (WldS) axons and this phenotype could

  17. Inner nuclear layer thickening is inversley proportional to retinal ganglion cell loss in optic neuritis.

    PubMed

    Kaushik, Megha; Wang, Chen Yu; Barnett, Michael H; Garrick, Raymond; Parratt, John; Graham, Stuart L; Sriram, Prema; Yiannikas, Con; Klistorner, Alexandr

    2013-01-01

    To examine the relationship between retinal ganglion cell loss and changes in the inner nuclear layer (INL) in optic neuritis (ON). 36 multiple sclerosis (MS) patients with a history of ON and 36 age and sex-matched controls underwent Optical Coherence Tomography. The paramacular retinal nerve fiber layer (RNFL), combined ganglion cell and inner plexiform layers (GCL/IPL) and inner nuclear layer (INL) thickness were measured at 36 points around the fovea. To remove inter-subject variability, the difference in thickness of each layer between the ON and fellow eye of each patient was calculated. A topographic analysis was conducted. The INL of the ON patients was thicker than the controls (42.9µm versus 39.6µm, p=0.002). ON patients also had a thinner RNFL (27.8µm versus 32.2µm, p<0.001) and GCL/IPL (69.3µm versus 98.1µm, p<0.001). Among the controls, there was no correlation between RNFL and GCL/IPL as well as RNFL and INL, but a positive correlation was seen between GCL/IPL and INL (r=0.65, p<0.001). In the ON group, there was a positive correlation between RNFL and GCL/IPL (r=0.80, p<0.001) but a negative correlation between RNFL and INL (r=-0.61, p<0.001) as well as GCL/IPL and INL (r=-0.44, p=0.007). The negative correlation between GCL/IPL and INL strengthened in the ON group when inter-subject variability was removed (r=-0.75, p<0.001). Microcysts within the INL were present in 5 ON patients, mainly in the superior and infero-nasal paramacular regions. While patients with microcysts lay at the far end of the correlation curve between GCL/IPL and INL (i.e. larger INL and smaller GCL/IPL compared to other patients), their exclusion did not affect the correlation (r= -0.76, p<0.001). INL enlargement in MS-related ON is associated with the severity of GCL loss. This is a continuous relationship and patients with INL microcysts may represent the extreme end of the scale.

  18. Inner Nuclear Layer Thickening Is Inversley Proportional to Retinal Ganglion Cell Loss in Optic Neuritis

    PubMed Central

    Kaushik, Megha; Wang, Chen Yu; Barnett, Michael H.; Garrick, Raymond; Parratt, John; Graham, Stuart L.; Sriram, Prema; Yiannikas, Con; Klistorner, Alexandr

    2013-01-01

    Aim To examine the relationship between retinal ganglion cell loss and changes in the inner nuclear layer (INL) in optic neuritis (ON). Methods 36 multiple sclerosis (MS) patients with a history of ON and 36 age and sex-matched controls underwent Optical Coherence Tomography. The paramacular retinal nerve fiber layer (RNFL), combined ganglion cell and inner plexiform layers (GCL/IPL) and inner nuclear layer (INL) thickness were measured at 36 points around the fovea. To remove inter-subject variability, the difference in thickness of each layer between the ON and fellow eye of each patient was calculated. A topographic analysis was conducted. Results The INL of the ON patients was thicker than the controls (42.9µm versus 39.6µm, p=0.002). ON patients also had a thinner RNFL (27.8µm versus 32.2µm, p<0.001) and GCL/IPL (69.3µm versus 98.1µm, p<0.001). Among the controls, there was no correlation between RNFL and GCL/IPL as well as RNFL and INL, but a positive correlation was seen between GCL/IPL and INL (r=0.65, p<0.001). In the ON group, there was a positive correlation between RNFL and GCL/IPL (r=0.80, p<0.001) but a negative correlation between RNFL and INL (r=-0.61, p<0.001) as well as GCL/IPL and INL (r=-0.44, p=0.007). The negative correlation between GCL/IPL and INL strengthened in the ON group when inter-subject variability was removed (r=-0.75, p<0.001). Microcysts within the INL were present in 5 ON patients, mainly in the superior and infero-nasal paramacular regions. While patients with microcysts lay at the far end of the correlation curve between GCL/IPL and INL (i.e. larger INL and smaller GCL/IPL compared to other patients), their exclusion did not affect the correlation (r= -0.76, p<0.001). Conclusions INL enlargement in MS-related ON is associated with the severity of GCL loss. This is a continuous relationship and patients with INL microcysts may represent the extreme end of the scale. PMID:24098599

  19. Changes in axonally transported proteins during axon regeneration in toad retinal ganglion cells

    PubMed Central

    1981-01-01

    In an effort to understand the regulation of the transition of a mature neuron to the growth, or regenerating, state we have analyzed the composition of the axonally transported proteins in the retinal ganglion cells of the toad Bufo marinus after inducing axon regeneration by crushing the optic nerve. At increasing intervals after axotomy, we labeled the retinal ganglion cells with [35S]methionine and subsequently analyzed the labeled transported polypeptides in the crushed optic nerve by means of one- and two-dimensional electrophoretic techniques. The most significant conclusion from these experiments is that, while the transition from the mature to the regenerating state does not require a gross qualitative alteration in the composition of axonally transported proteins, the relative labeling of a small subset of rapidly transported proteins is altered dramatically (changes of more than 20-fold) and reproducibly (more than 30 animals) by axotomy. One of these growth-associated proteins (GAPs) was soluble in an aqueous buffer, while three were associated with a crude membrane fraction. The labeling of all three of the membrane- associated GAPs increased during the first 8 d after axotomy, and they continued to be labeled for at least 4 wk. The modulation of these proteins after axotomy is consistent with the possibility that they are involve in growth-specific functions and that the altered expression of a small number of genes is a crucial regulatory event in the transition of a mature neuron to a growth state. In addition to these selective changes in rapidly transported proteins, we observed the following more general metabolic correlates of the regeneration process: The total radioactive label associated with the most rapidly transported proteins (groups I and II) increased three to fourfold during the first 8 d after the nerve was crushed, while the total label associated with more slowly moving proteins (group IV) increased about 10-fold during this same

  20. GAP-43 expression is upregulated in retinal ganglion cells after ischemia/reperfusion-induced damage.

    PubMed

    Dijk, Frederike; Bergen, Arthur A B; Kamphuis, Willem

    2007-05-01

    In response to injury, the adult mammalian retina shows signs of structural remodeling, possibly in an attempt to preserve or regain some of its functional neural connections. In order to study the mechanisms involved in injury-induced plasticity, we have studied changes in growth associated protein 43 (GAP-43) after retinal ischemia/reperfusion in the rat. GAP-43 is a marker for neuronal remodeling and is involved in synapse formation. Ischemic injury of the rat retina was induced by 60 min of ischemia followed by reperfusion times varying from 2h up to 4 weeks. GAP-43 mRNA levels were significantly increased between 12h and 72 h reperfusion with a peak around 24h. GAP-43 specific antibodies showed that the total amount of GAP-43 labeling in the inner plexiform layer was diminished after 12h of reperfusion by approximately 35% and remained at this level up to 1 week postischemia despite the reduction in thickness of this layer during this period resulting from the ischemia-induced cell loss. At 2 and 4 weeks reperfusion, the amount of labeling was reduced by 70%, simultaneously with a decrease of GAP-43 transcript level. Between 72 h up to 2 weeks postischemia, the induction of intense GAP-43 labeling was observed in NeuN- and beta-tubulin-positive ganglion cell somata and in horizontally and vertically oriented processes in the inner plexiform layer. Ischemia also induced GAP-43 expression in some GFAP-positive Müller cells. Double-labeling showed that in controls and after ischemia GAP-43 was expressed by some amacrine cells of the glycinergic (glycine transporter 1), calretinin-positive, and dopaminergic (tyrosine hydroxylase) subpopulations. No increase of GAP-43 expression levels was found in these amacrine cells. The results demonstrate that ganglion cells show an elevated expression of GAP-43 after ischemia-inflicted damage. These findings suggest a temporal window during which ganglion cells may remodel their neuronal network in the damaged retina.

  1. Ontogenetic changes in retinal ganglion cell distribution and spatial resolving power in the brown-banded bamboo shark Chiloscyllium punctatum (Elasmobranchii).

    PubMed

    Harahush, Blake K; Hart, Nathan S; Collin, Shaun P

    2014-01-01

    The development of the visual system in anamniotic vertebrates is a continual process, allowing for ontogenetic changes in retinal topography and spatial resolving power. We examined the number and distribution of retinal ganglion cells in wholemounted retinae throughout the protracted embryonic development (∼5 months) of a chondrichthyan, i.e. the brown-banded bamboo shark Chiloscyllium punctatum, from the beginning of retinal cell differentiation (approximately halfway through embryogenesis) to adulthood. We also identified and quantified the number of apoptosed cells within the ganglion cell layer to evaluate the contribution of apoptosis to changes in retinal topography. C. punctatum undergoes rapid changes in ganglion cell distribution during embryogenesis, where high levels of apoptosis, especially around the retinal periphery, result in relative increases in ganglion cell density in the central retina which progressively extend nasally and temporally to form a meridional band at hatching. After hatching, C. punctatum forms and maintains a horizontal streak, showing only minor changes in topography during growth, with basal levels of apoptosis. The total number of retinal ganglion cells reaches 547,881 in adult sharks, but the mean (3,228 cells·mm(-2)) and peak (4,983 cells·mm(-2)) retinal ganglion cell densities are highest around the time of hatching. Calculated estimates of spatial resolving power, based on ganglion cell spacing (assuming a hexagonal mosaic) and assessment of the focal length from cryosections of the eye, increase from 1.47 cycles·degree(-1) during embryogenesis to 4.29 cycles·degree(-1) in adults. The increase in spatial resolving power across the retinal meridian would allow this species to hunt and track faster, more mobile prey as it reaches maturity.

  2. Transient ipsilateral retinal ganglion cell projections to the brain: Extent, targeting and disappearance

    PubMed Central

    Soares, Célia A.; Mason, Carol A.

    2015-01-01

    During development of the mammalian eye, the first retinal ganglion cells (RGCs) that extend to the brain are located in the dorsocentral retina. These RGCs extend to either ipsilateral or contralateral targets, but the ipsilateral projections do not survive into postnatal periods. The function and means of disappearance of the transient ipsilateral projection are not known. We have followed the course of this transient early ipsilateral cohort of RGCs, paying attention to how far they extend, whether they enter targets and if so, which ones, and the time course of their disappearance. The dorsocentral ipsilateral RGC axons were traced using DiI labeling at E13.5 and 15.5 to compare the proportion of ipsi-versus contralateral projections during the first period of growth. In utero electroporation of E12.5 retina with GFP constructs was used to label axons that could be visualized at succeeding time points into postnatal ages. Our results show that the earliest ipsilateral axons grow along the cellular border of the brain, and are segregated from the laterally-postioned contralateral axons from the same retinal origin. In agreement with previous reports, although many early RGCs extend ipsilaterally, after E16 their number rapidly declines. Nonetheless, some ipsilateral axons from the dorsocentral retina enter the superior colliculus (SC) and arborize minimally, but very few enter the dorsal lateral geniculate nucleus (dLGN) and those that do extend only short branches. While the mechanism of selective axonal disappearance remains elusive, these data give further insight into establishment of the visual pathways. PMID:25788284

  3. Melatonin potentiates glycine currents through a PLC/PKC signalling pathway in rat retinal ganglion cells.

    PubMed

    Zhao, Wen-Jie; Zhang, Min; Miao, Yanying; Yang, Xiong-Li; Wang, Zhongfeng

    2010-07-15

    In vertebrate retina, melatonin regulates various physiological functions. In this work we investigated the mechanisms underlying melatonin-induced potentiation of glycine currents in rat retinal ganglion cells (RGCs). Immunofluorescence double labelling showed that rat RGCs were solely immunoreactive to melatonin MT(2) receptors. Melatonin potentiated glycine currents of RGCs, which was reversed by the MT(2) receptor antagonist 4-P-PDOT. The melatonin effect was blocked by intracellular dialysis of GDP-beta-S. Either preincubation with pertussis toxin or application of the phosphatidylcholine (PC)-specific phospholipase C (PLC) inhibitor D609, but not the phosphatidylinositol (PI)-PLC inhibitor U73122, blocked the melatonin effect. The protein kinase C (PKC) activator PMA potentiated the glycine currents and in the presence of PMA melatonin failed to cause further potentiation of the currents, whereas application of the PKC inhibitor bisindolylmaleimide IV abolished the melatonin-induced potentiation. The melatonin effect persisted when [Ca(2+)](i) was chelated by BAPTA, and melatonin induced no increase in [Ca(2+)](i). Neither cAMP-PKA nor cGMP-PKG signalling pathways seemed to be involved because 8-Br-cAMP or 8-Br-cGMP failed to cause potentiation of the glycine currents and both the PKA inhibitor H-89 and the PKG inhibitor KT5823 did not block the melatonin-induced potentiation. In consequence, a distinct PC-PLC/PKC signalling pathway, following the activation of G(i/o)-coupled MT(2) receptors, is most likely responsible for the melatonin-induced potentiation of glycine currents of rat RGCs. Furthermore, in rat retinal slices melatonin potentiated light-evoked glycine receptor-mediated inhibitory postsynaptic currents in RGCs. These results suggest that melatonin, being at higher levels at night, may help animals to detect positive or negative contrast in night vision by modulating inhibitory signals largely mediated by glycinergic amacrine cells in the inner

  4. Estimating the rate of retinal ganglion cell loss to detect glaucoma progression

    PubMed Central

    Hirooka, Kazuyuki; Izumibata, Saeko; Ukegawa, Kaori; Nitta, Eri; Tsujikawa, Akitaka

    2016-01-01

    Abstract This study aimed to evaluate the relationship between glaucoma progression and estimates of the retinal ganglion cells (RGCs) obtained by combining structural and functional measurements in patients with glaucoma. In the present observational cohort study, we examined 116 eyes of 62 glaucoma patients. Using Cirrus optical coherence tomography (OCT), a minimum of 5 serial retinal nerve fiber layer (RNFL) measurements were performed in all eyes. There was a 3-year separation between the first and last measurements. Visual field (VF) testing was performed on the same day as the RNFL imaging using the Swedish Interactive Threshold Algorithm Standard 30–2 program of the Humphrey Field Analyzer. Estimates of the RGC counts were obtained from standard automated perimetry (SAP) and OCT, with a weighted average then used to determine a final estimate of the number of RGCs for each eye. Linear regression was used to calculate the rate of the RGC loss, and trend analysis was used to evaluate both serial RNFL thicknesses and VF progression. Use of the average RNFL thickness parameter of OCT led to detection of progression in 14 of 116 eyes examined, whereas the mean deviation slope detected progression in 31 eyes. When the rates of RGC loss were used, progression was detected in 41 of the 116 eyes, with a mean rate of RGC loss of −28,260 ± 8110 cells/year. Estimation of the rate of RGC loss by combining structural and functional measurements resulted in better detection of glaucoma progression compared to either OCT or SAP. PMID:27472691

  5. Tetramethylpyrazine nitrone protects retinal ganglion cells against N-methyl-d-aspartate-induced excitotoxicity.

    PubMed

    Luo, Xiaopeng; Yu, Yankun; Xiang, Zongqin; Wu, Huisu; Ramakrishna, Seeram; Wang, Yuqiang; So, Kwok-Fai; Zhang, Zaijun; Xu, Ying

    2017-02-03

    Adding a free radical-scavenging nitrone moiety on tetramethylpyrazine, we have previously synthesized a chemical named 2-[[(1,1-dimethylethyl)oxidoimino]-methyl]-3,5,6-trimethylpyrazine (tetramethylpyrazine nitrone, or TBN) and proved its neuroprotective effect but with limited understanding of its mechanism. Here we ask if TBN protects retinal ganglion cells (RGCs) against excitotoxicity induced by NMDA and explore the underlying mechanism. NMDA was intravitreally injected to induce RGC injury in rats, followed by daily intraperitoneal administrations of TBN. Measurements of TBN concentration at different times after intraperitoneal administration showed that more than 200 μM TBN reached the aqueous humor quickly. Then RGCs' survival was evaluated by quantifying Brn3-positive cells, and retinal functions were examined by electroretinogram and visual behaviors. TBN significantly increased the survival of RGCs after NMDA insult, recovered the amplitude of photopic negative responses to flash, and restored the visual behavior. Furthermore, TBN inhibited the apoptotic process, as indicated by the elevated ratios of cleaved caspase-3/caspase-3 and of Bax/Bcl-2, and decreased the level of reactive oxygen species. Moreover, TBN reduced RGC's calcium overload induced by NMDA or by KCl. Whole-cell patch recording from RGCs further showed that TBN slightly but significantly inhibited L-type calcium channels, but had little effect on T-type calcium channel or NMDA-, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid(AMPA)-induced current. Thus our data indicate that TBN alleviates NMDA-elicited injury of rat RGCs both morphologically and functionally, possibly by inhibiting the L-type calcium channel thus reducing Ca(2+) overload and by directly scavenging free radicals. Therefore, TBN may be a novel candidate for treating excitotoxicity-related visual disorders such as glaucoma.

  6. Neuroprotection by GH against excitotoxic-induced cell death in retinal ganglion cells.

    PubMed

    Martínez-Moreno, Carlos G; Ávila-Mendoza, José; Wu, Yilun; Arellanes-Licea, Elvira Del Carmen; Louie, Marcela; Luna, Maricela; Arámburo, Carlos; Harvey, Steve

    2016-08-01

    Retinal growth hormone (GH) has been shown to promote cell survival in retinal ganglion cells (RGCs) during developmental waves of apoptosis during chicken embryonic development. The possibility that it might also against excitotoxicity-induced cell death was therefore examined in the present study, which utilized quail-derived QNR/D cells as an in vitro RGC model. QNR/D cell death was induced by glutamate in the presence of BSO (buthionine sulfoxamide) (an enhancer of oxidative stress), but this was significantly reduced (P<0.01) in the presence of exogenous recombinant chicken GH (rcGH). Similarly, QNR/D cells that had been prior transfected with a GH plasmid to overexpress secreted and non-secreted GH. This treatment reduced the number of TUNEL-labeled cells and blocked their release of lactate dehydrogenase (LDH). In a further experiment with dissected neuroretinal explants from ED (embryonic day) 10 embryos, rcGH treatment of the explants also reduced (P<0.01) the number of glutamate-BSO-induced apoptotic cells and blocked the explant release of LDH. This neuroprotective action was likely mediated by increased STAT5 phosphorylation and increased bcl-2 production, as induced by exogenous rcGH treatment and the media from GH-overexpressing QNR/D cells. As rcGH treatment and GH-overexpression cells also increased the content of IGF-1 and IGF-1 mRNA this neuroprotective action of GH is likely to be mediated, at least partially, through an IGF-1 mechanism. This possibility is supported by the fact that the siRNA knockdown of GH or IGF-1 significantly reduced QNR/D cell viability, as did the immunoneutralization of IGF-1. GH is therefore neuroprotective against excitotoxicity-induced RGC cell death by anti-apoptotic actions involving IGF-1 stimulation.

  7. Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma

    PubMed Central

    Pitha, Ian F.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary Ellen; Oglesby, Ericka N.; Berlinicke, Cynthia A.; Mitchell, Katherine L.; Kim, Jessica; Jefferys, Joan J.

    2015-01-01

    Purpose To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice. Methods We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Results Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP. Conclusions The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes

  8. Transient ipsilateral retinal ganglion cell projections to the brain: Extent, targeting, and disappearance.

    PubMed

    Soares, Célia A; Mason, Carol A

    2015-12-01

    During development of the mammalian eye, the first retinal ganglion cells (RGCs) that extend to the brain are located in the dorsocentral (DC) retina. These RGCs extend to either ipsilateral or contralateral targets, but the ipsilateral projections do not survive into postnatal periods. The function and means of disappearance of the transient ipsilateral projection are not known. We have followed the course of this transient early ipsilateral cohort of RGCs, paying attention to how far they extend, whether they enter targets and if so, which ones, and the time course of their disappearance. The DC ipsilateral RGC axons were traced using DiI labeling at E13.5 and E15.5 to compare the proportion of ipsi- versus contralateral projections during the first period of growth. In utero electroporation of E12.5 retina with GFP constructs was used to label axons that could be visualized at succeeding time points into postnatal ages. Our results show that the earliest ipsilateral axons grow along the cellular border of the brain, and are segregated from the laterally positioned contralateral axons from the same retinal origin. In agreement with previous reports, although many early RGCs extend ipsilaterally, after E16 their number rapidly declines. Nonetheless, some ipsilateral axons from the DC retina enter the superior colliculus and arborize minimally, but very few enter the dorsal lateral geniculate nucleus and those that do extend only short branches. While the mechanism of selective axonal disappearance remains elusive, these data give further insight into establishment of the visual pathways.

  9. Retinal Ganglion Cell Morphology after Optic Nerve Crush and Experimental Glaucoma

    PubMed Central

    Kalesnykas, Giedrius; Oglesby, Ericka N.; Zack, Donald J.; Cone, Frances E.; Steinhart, Matthew R.; Tian, Jing; Pease, Mary E.; Quigley, Harry A.

    2012-01-01

    Purpose. To study sequential changes in retinal ganglion cell (RGC) morphology in mice after optic nerve crush and after induction of experimental glaucoma. Methods. Nerve crush or experimental glaucoma was induced in mice that selectively express yellow fluorescent protein (YFP) in RGCs. Mice were euthanized 1, 4, and 9 days after crush and 1, 3, and 6 weeks after induction of glaucoma by bead injection. All YFP-RGCs were identified in retinal whole mounts. Then confocal images of randomly selected RGCs were quantified for somal fluorescence brightness, soma size, neurite outgrowth, and dendritic complexity (Sholl analysis). Results. By 9 days after crush, 98% of RGC axons died and YFP-RGCs decreased by 64%. After 6 weeks of glaucoma, 31% of axons died, but there was no loss of YFP-RGC bodies. All crush retinas combined had significant decreases in neurite outgrowth parameters (P ≤ 0.036, generalized estimating equation [GEE] model) and dendritic complexity was lower than controls (P = 0.017, GEE model). There was no change in RGC soma area after crush. In combined glaucoma data, the RGC soma area was larger than control (P = 0.04, GEE model). At 3 weeks, glaucoma RGCs had significantly larger values for dendritic structure and complexity than controls (P = 0.044, GEE model), but no statistical difference was found at 6 weeks. Conclusions. After nerve crush, RGCs and axons died rapidly, and dendritic structure decreased moderately in remaining RGCs. Glaucoma caused an increase in RGC dendrite structure and soma size at 3 weeks. PMID:22589442

  10. Retinal Ganglion Cell Dysfunction in Asymptomatic G11778A: Leber Hereditary Optic Neuropathy

    PubMed Central

    Guy, John; Feuer, William J.; Porciatti, Vittorio; Schiffman, Joyce; Abukhalil, Fawzi; Vandenbroucke, Ruth; Rosa, Potyra R.; Lam, Byron L.

    2014-01-01

    Purpose. To report the serial evaluation of asymptomatic eyes of subjects with mutated G11778A mitochondrial DNA. Methods. Forty-five asymptomatic G11778A Leber hereditary optic neuropathy (LHON) carriers and two patients with the mutation who developed unilateral visual loss underwent testing that included visual acuity, automated visual field, pattern electroretinogram (PERG), and spectral-domain optical coherence tomography every 6 months between September 2008 and March 2012. Results. Visual acuity, visual fields, and retinal nerve fiber layer thickness remained stable within the normal range. Mean PERG amplitudes of carriers dropped progressively by ∼40% from baseline to 36 months. In addition, comparisons with the fellow eyes of patients with unilateral optic neuritis revealed a 3.4 ETDRS (Early Treatment Diabetic Retinopathy Study) letter loss in the LHON carriers. A single carrier developed visual loss, with PERG amplitudes dropping by half. In one of two LHON cases who presented with unilateral visual loss, visual acuity in the asymptomatic eye was ∼20/40 at baseline. The PERG amplitude of this eye was reduced to ∼30% of normal. Six months later, his visual acuity had dropped to ∼20/500. A second patient who was ∼20/20 and had a visual field defect in the asymptomatic eye at baseline remained at this level for the 18 months of follow-up. His PERG amplitudes were similar to those of asymptomatic carriers, with 0.78 μV at baseline that did not decline with follow-up. Conclusions. Declines of the PERG amplitude suggest subclinical retinal ganglion cell dysfunction in asymptomatic G11778A subjects, which is progressive. PMID:24398093

  11. Synaptic inputs to retinal ganglion cells that set the circadian clock

    PubMed Central

    Perez-Leon, Jorge Alberto; Warren, Erin J.; Allen, Charles N.; Robinson, David W.; Brown, R. Lane

    2008-01-01

    Melanopsin-containing retinal ganglion cells (RGCs) project to the suprachiasmatic nuclei (SCN) and mediate photoentrainment of the circadian system. Melanopsin is a novel retinal-based photopigment that renders these cells intrinsically photosensitive (ip). Although genetic ablation of melanopsin abolishes the intrinsic light response, it has a surprisingly minor effect on circadian photoentrainment. This and other non-visual responses to light are lost only when the melanopsin deficiency is coupled with mutations that disable classical rod and cone photoreceptors, suggesting that melanopsin-containing RGCs also receive rod- and cone-driven synaptic inputs. Using whole-cell patch-clamp recording, we demonstrate that light triggers synaptic currents in ipRGCs via activation of ionotropic glutamate and γ-aminobutyric acid (GABA) receptors. Miniature postsynaptic currents (mPSCs) were clearly observed in ipRGCs, although they were less robust and were seen less frequently than those seen in non-ip cells. Pharmacological treatments revealed that the majority of ipRGCs receive excitatory glutamatergic inputs that were blocked by DNQX and/or kynurenic acid, as well as inhibitory GABAergic inputs that were blocked by bicuculline. Other ipRGCs received either glutamatergic or GABAergic inputs nearly exclusively. Although strychnine (Strych)-sensitive mPSCs were evident on many non-ipRGCs, indicating the presence of glycinergic inputs, we saw no evidence of Strych-sensitive events in ipRGCs. Based on these results, it is clear that SCN-projecting RGCs can respond to light both via an intrinsic melanopsin-based signaling cascade and via a synaptic pathway driven by classical rod and/or cone photoreceptors. It remains to be determined how the ipRGCs integrate these temporally distinct inputs to generate the signals that mediate circadian photoentrainment and other non-visual responses to light. PMID:16930437

  12. Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma.

    PubMed

    Quigley, Harry A; Pitha, Ian F; Welsbie, Derek S; Nguyen, Cathy; Steinhart, Matthew R; Nguyen, Thao D; Pease, Mary Ellen; Oglesby, Ericka N; Berlinicke, Cynthia A; Mitchell, Katherine L; Kim, Jessica; Jefferys, Joan J; Kimball, Elizabeth C

    2015-01-01

    To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice. We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP. The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes in the sclera expressed at the

  13. Topography and morphology of retinal ganglion cells in Falconiforms: a study on predatory and carrion-eating birds.

    PubMed

    Inzunza, O; Bravo, H; Smith, R L; Angel, M

    1991-02-01

    The topographic distribution of retinal ganglion cells and their cell body size have been studied in five Falconiform species, including predatory (chilean eagle Buteo fuscenses australis, and sparrow hawk Falco sparverius) and carrion-eating (chimango caracara Milvago chimango; condor Vultur gryphus, and black vulture Coragyps atratus) birds. All these species had a well defined nasal fovea and a horizontal streak. Instead of a temporal fovea as in eagles and hawks, an afoveate temporal area is present in chimango, condor, and vulture. The highest ganglion cell density was found in the nasal fovea of Falco and Buteo with 65,000 and 62,000 cells/mm2, respectively. A negative correlation between ganglion cell density and cell body size was found in all the species studied. The specializations of the temporal retina showed a rather homogenous population of medium sized neurons, while the nasal foveas showed a homogeneous population of smaller ganglion cells. Finally, the peripheral retina showed a heterogeneous population of large, medium, and small ganglion cells. Predatory behavior appears to be closely related to foveal specializations, and is best exemplified in the eagle and hawk and to a lesser extent in the chimango.

  14. Apelin-36 is protective against N-methyl-D-aspartic-acid-induced retinal ganglion cell death in the mice.

    PubMed

    Sakamoto, Kenji; Murakami, Yuta; Sawada, Shohei; Ushikubo, Hiroko; Mori, Asami; Nakahara, Tsutomu; Ishii, Kunio

    2016-11-15

    Retinal ganglion cell death in glaucoma is caused at least in part by a large Ca(2+) influx through N-methyl-D-aspartic acid (NMDA) receptors. Apelin is a peptide originally found in the tissue extracts of bovine stomach. Recent studies have been shown that apelin protects against the ischemic-reperfused injury in the brain. We examined whether apelin had protective effects on the NMDA-induced retinal ganglion cell (RGC) death using B6.Cg-TgN(Thy1-CFP)23Jrs/J transgenic mice, which express the enhanced cyan fluorescent protein in RGCs in the retina, in vivo. The mice were anesthetized by ketamine and xylazine, and NMDA (40 nmol/eye) was intravitreally injected. We evaluated the effects of apelin-13, [Glp(1)]-apelin-13, a potent agonist of apelin receptor, and apelin-36 on the NMDA-induced retinal ganglion cell death. NMDA-induced retinal ganglion cell loss was clearly seen 7 days after NMDA injection. Intravitreal apelin-36 (0.33 nmol/eye), but not apelin-13 (1 nmol/eye) nor [Glp(1)]-apelin-13 (1 nmol/eye), simultaneously injected with NMDA significantly reduced the cell loss. The protective effect of apelin-36 was not reduced by ML221 (0.1 nmol/eye; 5-[(4-Nitrobenzoyl)oxy]-2-[(2-pyrimidinylthio)methyl]-4H-pyran-4-one), an apelin receptor antagonist, GF109203X (0.03 nmol/eye), a protein kinase C inhibitor, U0126 (0.2 nmol/eye), a MAPK/ERK kinase inhibitor, LY294002 (0.1 nmol/eye), a phosphoinositide 3-kinase inhibitor, Akti 1/2 (0.05 nmol/eye), an Akt inhibitor, or 4,5,6,7-tetrabromobenzotriazole (0.2 nmol/eye), a casein kinase-2 inhibitor. In addition, human apelin-36 did not affect the kainic-acid (20 nmol/eye)-induced ganglion cell death. The present study suggests that apelin-36 protects against the NMDA-induced ganglion cell death independently of the activation of apelin receptor in the murine retina in vivo.

  15. Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

    PubMed Central

    Han, Ming-lei; Liu, Guo-hua; Guo, Jin; Yu, Shu-juan; Huang, Jing

    2016-01-01

    Retinal ganglion cell (RGC) degeneration is irreversible in glaucoma and tyrosine kinase receptor B (TrkB)-associated signaling pathways have been implicated in the process. In this study, we attempted to examine whether imipramine, a tricyclic antidepressant, may protect hydrogen peroxide (H2O2)-induced RGC degeneration through the activation of the TrkB pathway in RGC-5 cell lines. RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H2O2. Western blot assay showed that in H2O2 -damaged RGC-5 cells, imipramine activated TrkB pathways through extracellular signal-regulated protein kinase/TrkB phosphorylation. TUNEL staining assay also demonstrated that imipramine ameliorated H2O2 -induced apoptosis in RGC-5 cells. Finally, TrkB-IgG intervention was able to reverse the protective effect of imipramine on H2O2 -induced RGC-5 apoptosis. Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the TrkB signaling pathway. PMID:27127489

  16. Effect of ATF3-deletion on apoptosis of cultured retinal ganglion cells

    PubMed Central

    Sun, Ming-Ming; Wang, Ya-Chen; Li, Yi; Guo, Xiao-Dan; Chen, Yan-Ming; Zhang, Zhong-Zhi

    2017-01-01

    AIM To investigate the effect of activating transcription factor-3 (ATF3)-deletion on apoptosis of cultured retinal ganglion cells (RGCs). METHODS Three ATF3 siRNA (ATF3-rat-651, ATF3-rat-319, ATF3-rat-520) were constructed, and were transiently transfected into RGC-5 cells. Quantitative real-time polymerase chain reaction (PCR) was used to examine ATF3 expression and the most effective ATF3 siRNA was selected for further studies. Flow cytometry was applied to investigate the effects of ATF3 deletion on RGC-5 apoptosis under elevated hydrostatic pressure. Quantitative real-time PCR and Western blot were performed to validate differentially expressed genes and proteins in ATF3-knockdown RGC-5 cells. RESULTS ATF3 specific siRNA effectively down-regulated ATF3 expression and significantly inhibited cell apoptosis in RGC-5 cells. Quantitative real-time PCR and Western blot confirmed that ATF3 knockdown remarkably decreased Jun-B and increased c-Jun at both mRNA and protein levels in RGC-5 cells. CONCLUSION ATF/cAMP-response element-binding family of transcription factors may be involved in the development of glaucoma and could be novel treatment targets for glaucoma. PMID:28546922

  17. Melanopsin-encoded response properties of intrinsically photosensitive retinal ganglion cells

    PubMed Central

    Mure, Ludovic S.; Hatori, Megumi; Zhu, Quansheng; Demas, James; Kim, Irene M.; Nayak, Surendra K.; Panda, Satchidananda

    2016-01-01

    SUMMARY Melanopsin photopigment expressed in intrinsically photosensitive retinal ganglion cells (ipRGCs) plays a crucial role in the adaptation of mammals to their ambient light environment through both image-forming and non-image-forming (NIF) visual responses. ipRGCs are structurally and functionally distinct from classical rod/cone photoreceptors and have unique properties including single-photon response, long response latency, photon integration over time, and slow deactivation. Here we discovered that amino-acid sequence features of melanopsin protein contribute to the functional properties of the ipRGCs. Phosphorylation of a cluster of Ser/Thr residues in the C-terminal cytoplasmic region of melanopsin contributes to deactivation, which in turn determines response latency and threshold sensitivity of the ipRGCs. The poorly conserved region distal to phosphorylation cluster inhibits functional role of phosphorylation, thereby constituting a unique delayed-deactivation mechanism. Concerted action of both regions sustains responses to dim light, allows for the integration of light over time, and results in precise signal duration. PMID:27181062

  18. Apigenin prevents TNF-α induced apoptosis of primary rat retinal ganglion cells.

    PubMed

    Fu, M-S; Zhu, B-J; Luo, D-W

    2014-11-25

    TNF-α has recently been identified to be a mediator of retinal ganglion cell (RGC) death, while glial cells are relatively protected against this death stimulus. Exposure of RGCs to TNF-α is thought to contribute to RGC apoptosis. Apigenin is a flavone with powerful anti-inflammatory properties that exists naturally in various plants and Chinese medicine. In our study, MTT assays showed that apigenin significantly inhibited the decrease of RGC viability induced by TNF-α in a dose-dependent manner. Pretreatment with apigenin prevented TNF-α-induced apoptosis in a dose-dependent manner as shown by flow cytometry. The production of ATP and the total oxygen uptake were also promoted after apigenin administration. TNF-α stimulation led to a significant reduction of bcl-2 and enhancement of bax, which was reversed by apigenin treatment. Apigenin treatment also alleviated the increased caspase-3 activity induced by TNF-α. Moreover, luciferase reporter assay indicated that apigenin dose-dependently decreased NF-κB activation induced by TNF-α, but had no significant effect on activation of AP-1. Collectively, these data demonstrated that apigenin alleviated TNF-α-induced apoptosis through inhibition of caspase-dependent apoptotic pathway and activation of nuclear factor-kappaB. Therefore, apigenin may be developed as an anti-apoptotic drug to treat retinopathy.

  19. Enhanced Retinal Ganglion Cell Survival in Glaucoma by Hypoxic Postconditioning After Disease Onset.

    PubMed

    Gidday, Jeffrey M; Zhang, Lihong; Chiang, Chia-Wen; Zhu, Yanli

    2015-04-01

    The neuroprotective efficacy of adaptive epigenetics, wherein beneficial gene expression changes are induced by nonharmful "conditioning" stimuli, is now well established in several acute, preclinical central nervous system injury models. Recently, in a mouse model of glaucoma, we demonstrated retinal ganglion cell (RGC) protection by repetitively "preconditioning" with hypoxia prior to disease onset, indicating an epigenetic approach may also yield benefits in chronic neurodegenerative disease. Herein, we determined whether presenting the repetitive hypoxic stimulus after disease initiation [repetitive hypoxic "postconditioning" (RH-Post)] could afford similar functional and morphologic protection against glaucomatous RGC injury. Chronic elevations in intraocular pressure (IOP) were induced unilaterally in adult male C57BL/6 mice by episcleral vein ligation. Mice were randomized to an RH-Post [1 h of systemic hypoxia (11% oxygen) every other day, starting 4 days after IOP elevation] or an untreated control group. After 3 weeks of experimental glaucoma, the 21-27% reduction and 5-25% prolongation in flash visual-evoked potential amplitudes and latencies, respectively, and the 30% impairment in visual acuity were robustly improved in RH-Post-treated mice, as was the 17% loss in RGC soma number and 20% reduction in axon integrity. These protective effects were observed without RH-Post affecting IOP. The present findings demonstrate that functional and morphologic protection of RGCs can be realized by stimulating epigenetic responses during the early stages of disease, and thus constitute a new conceptual approach to glaucoma therapeutics.

  20. Activation of autophagy induces retinal ganglion cell death in a chronic hypertensive glaucoma model

    PubMed Central

    Park, H-Y Lopilly; Kim, J H; Park, C K

    2012-01-01

    Autophagy is reported to have important roles in relation to regulated cell death pathways and neurodegeneration. This study used chronic hypertensive glaucoma rat model to investigate whether the autophagy pathway has a role in the apoptosis of retinal ganglion cells (RGCs) after chronic intraocular pressure (IOP) elevation. Under electron microscopy, autophagosomes were markedly accumulated in the dendrites and cytoplasm of RGCs after IOP elevation. Western blot analysis showed that LC3-II/LC3-I and beclin-1 were upregulated throughout the 8-weeks period after IOP elevation. The pattern of LC3 immunostaining showed autophagy activation in the cytoplasm of RGCs to increase and peak at 4 weeks after IOP elevation. Most of these LC3B-positive RGCs underwent apoptosis by terminal deoxynucleotidyltransferase-mediated biotinylated UTP nick end labeling, and inhibition of autophagy with 3-methyladenine decreased RGC apoptosis. The activated pattern shows that autophagy is initially activated in the dendrites of the RGCs, but, thereafter autophagy is mainly activated in the cytoplasm of RGCs. This may show that autophagy is differently regulated in different compartments of the neuron. This present study showed that autophgy is activated in RGCs and has a role in autophagic cell death after chronic IOP elevation. PMID:22476098

  1. Number and spatial distribution of intrinsically photosensitive retinal ganglion cells in the adult albino rat.

    PubMed

    Galindo-Romero, C; Jiménez-López, M; García-Ayuso, D; Salinas-Navarro, M; Nadal-Nicolás, F M; Agudo-Barriuso, M; Villegas-Pérez, M P; Avilés-Trigueros, M; Vidal-Sanz, M

    2013-03-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond directly to light and are responsible of the synchronization of the circadian rhythm with the photic stimulus and for the pupillary light reflex. To quantify the total population of rat-ipRGCs and to assess their spatial distribution we have developed an automated routine and used neighbour maps. Moreover, in all analysed retinas we have studied the general population of RGCs - identified by their Brn3a expression - and the population of ipRGCs - identified by melanopsin immunodetection - thus allowing the co-analysis of their topography. Our results show that the total mean number ± standard deviation of ipRGCs in the albino rat is 2047 ± 309. Their distribution in the retina seems to be complementary to that of Brn3a(+)RGCs, being denser in the periphery, especially in the superior retina where their highest densities are found in the temporal quadrant, above the visual streak. In addition, by tracing the retinas from both superior colliculi, we have also determined that 90.62% of the ipRGC project to these central targets.

  2. Schwann cells promote the survival of rat retinal ganglion cells after optic nerve section.

    PubMed Central

    Maffei, L; Carmignoto, G; Perry, V H; Candeo, P; Ferrari, G

    1990-01-01

    Schwann cells (SCs) are known to play an important role for the regeneration of mammalian peripheral nerves. Their effect is likely due to the production of neuronotrophic and/or supportive factors. Here we study the effect of intraocular transplant of SCs on the survival of rat retinal ganglion cells (RGCs) after the intracranial section of the optic nerve. SCs were injected intraocularly in adult hooded rats. Surviving RGCs were retrogradely labeled with horseradish peroxidase applied to the proximal stump of the optic nerve. Results show that intraocular transplants of SCs promote the survival of a large number of RGCs for periods as long as 9 and 14 weeks after optic nerve section. In experimental retinae, surviving RGCs were 2- to 8-fold more numerous than in controls. This finding suggests that SCs are the source of factors that promote the survival of RGCs. Nerve growth factor is produced by SCs, and the intraocular injection of nerve growth factor has been previously shown to promote RGC survival. The rescuing effect of SCs on RGCs is greater than that obtained by intraocular injection of nerve growth factor. This greater effect may be due to the action of other neurotrophic factors produced by SCs or by transplanted SCs producing NGF in a sustained fashion. Images PMID:2308946

  3. Serum Response Factor Protects Retinal Ganglion Cells Against High-Glucose Damage.

    PubMed

    Cao, Yan; Wang, Liang; Zhao, Junhong; Zhang, Hongbing; Tian, Ying; Liang, Houcheng; Ma, Qiang

    2016-06-01

    Serum response factor (SRF), which encodes the MADS-box family of related proteins, is a common transcription factor related to the expression of genes associated with cell survival. However, SRF's role in retinal ganglion cells (RGCs) after high-glucose injury remains unclear. In this study, we investigate the protective role of SRF after high-glucose injury and its underlying mechanism. The in vitro RGC model subjected to high glucose was established by employing a 50 mmol/L glucose culture environment. As detected by real-time quantitative PCR and Western blot, SRF was significantly upregulated in RGCs treated with high glucose. Overexpression of SRF significantly promoted survival among RGCs exposed to high glucose and inhibited RGC apoptosis. Knockdown of SRF exerted an inverse effect. Moreover, SRF upregulation enhanced expression of an antioxidant protein, nuclear factor erythroid 2-related factor (Nrf2), via control of the Fos-related antigen 1 (Fra-1). SRF upregulation also affected RGC survival after high-glucose treatment. Our findings showed that overexpression of SRF promoted survival of RGCs after high-glucose injury by regulating Fra-1 and Nrf2.

  4. Fast estimation of motion from selected populations of retinal ganglion cells.

    PubMed

    Cerquera, Alexander; Freund, Jan

    2011-02-01

    We explore how the reconstruction efficiency of fast spike population codes varies with population size, population composition and code complexity. Our study is based on experiments with moving light patterns which are projected onto the isolated retina of a turtle Pseudemys scripta elegans. The stimulus features to reconstruct are sequences of velocities kept constant throughout segments of 500 ms. The reconstruction is based on the spikes of a retinal ganglion cell (RGC) population recorded extracellularly via a multielectrode array. Subsequent spike sorting yields the parallel spike trains of 107 RGCs as input to the reconstruction method, here a discriminant analysis trained and tested in jack-knife fashion. Motivated by behavioral response times, we concentrate on fast reconstruction, i.e., within 150 ms following a trigger event defined via significant changes of the population spike rate. Therefore, valid codes involve only few (≤3) spikes per cell. Using only the latency t(1) of each cell (with reference to the trigger event) corresponds to the most parsimonious population code considered. We evaluate the gain in reconstruction efficiency when supplementing t(1) by spike times t(2) and t(3). Furthermore, we investigate whether sub-populations of smaller size benefit significantly from a selection process or whether random compilations are equally efficient. As selection criteria we try different concepts (directionality, reliability, and discriminability). Finally, we discuss the implications of a selection process and its inter-relation with code complexity for optimized reconstruction.

  5. Retinal ganglion cell survival and axon regeneration after optic nerve injury in naked mole-rats.

    PubMed

    Park, Kevin K; Luo, Xueting; Mooney, Skyler J; Yungher, Benjamin J; Belin, Stephane; Wang, Chen; Holmes, Melissa M; He, Zhigang

    2017-02-01

    In the adult mammalian central nervous system (CNS), axonal damage often triggers neuronal cell death and glial activation, with very limited spontaneous axon regeneration. In this study, we performed optic nerve injury in adult naked mole-rats, the longest living rodent, with a maximum life span exceeding 30 years, and found that injury responses in this species are quite distinct from those in other mammalian species. In contrast to what is seen in other mammals, the majority of injured retinal ganglion cells (RGCs) survive with relatively high spontaneous axon regeneration. Furthermore, injured RGCs display activated signal transducer and activator of transcription-3 (STAT3), whereas astrocytes in the optic nerve robustly occupy and fill the lesion area days after injury. These neuron-intrinsic and -extrinsic injury responses are reminiscent of those in "cold-blooded" animals, such as fish and amphibians, suggesting that the naked mole-rat is a powerful model for exploring the mechanisms of neuronal injury responses and axon regeneration in mammals. J. Comp. Neurol. 525:380-388, 2017. © 2016 Wiley Periodicals, Inc.

  6. Electrical activity of ON and OFF retinal ganglion cells: a modelling study

    NASA Astrophysics Data System (ADS)

    Guo, Tianruo; Tsai, David; Morley, John W.; Suaning, Gregg J.; Kameneva, Tatiana; Lovell, Nigel H.; Dokos, Socrates

    2016-04-01

    Objective. Retinal ganglion cells (RGCs) demonstrate a large range of variation in their ionic channel properties and morphologies. Cell-specific properties are responsible for the unique way RGCs process synaptic inputs, as well as artificial electrical signals such as that from a visual prosthesis. A cell-specific computational modelling approach allows us to examine the functional significance of regional membrane channel expression and cell morphology. Approach. In this study, an existing RGC ionic model was extended by including a hyperpolarization activated non-selective cationic current as well as a T-type calcium current identified in recent experimental findings. Biophysically-defined model parameters were simultaneously optimized against multiple experimental recordings from ON and OFF RGCs. Main results. With well-defined cell-specific model parameters and the incorporation of detailed cell morphologies, these models were able to closely reconstruct and predict ON and OFF RGC response properties recorded experimentally. Significance. The resulting models were used to study the contribution of different ion channel properties and spatial structure of neurons to RGC activation. The techniques of this study are generally applicable to other excitable cell models, increasing the utility of theoretical models in accurately predicting the response of real biological neurons.

  7. Response properties of ON-OFF retinal ganglion cells to high-order stimulus statistics.

    PubMed

    Xiao, Lei; Gong, Han-Yan; Gong, Hai-Qing; Liang, Pei-Ji; Zhang, Pu-Ming

    2014-10-17

    The visual stimulus statistics are the fundamental parameters to provide the reference for studying visual coding rules. In this study, the multi-electrode extracellular recording experiments were designed and implemented on bullfrog retinal ganglion cells to explore the neural response properties to the changes in stimulus statistics. The changes in low-order stimulus statistics, such as intensity and contrast, were clearly reflected in the neuronal firing rate. However, it was difficult to distinguish the changes in high-order statistics, such as skewness and kurtosis, only based on the neuronal firing rate. The neuronal temporal filtering and sensitivity characteristics were further analyzed. We observed that the peak-to-peak amplitude of the temporal filter and the neuronal sensitivity, which were obtained from either neuronal ON spikes or OFF spikes, could exhibit significant changes when the high-order stimulus statistics were changed. These results indicate that in the retina, the neuronal response properties may be reliable and powerful in carrying some complex and subtle visual information.

  8. Ginsenoside Rb1 protects rat retinal ganglion cells against hypoxia and oxidative stress.

    PubMed

    Liu, Zhaochun; Chen, Juying; Huang, Wendong; Zeng, Zhi; Yang, Yongfei; Zhu, Banghao

    2013-11-01

    The current study was designed to investigate the effect of ginsenoside Rb1 (Rb1) on apoptosis induced by hypoxia and oxidative stress in a retinal ganglion cell line (RGC-5). The underlying mechanism was also investigated. RGC-5 cells were pretreated with 10 µmol/l Rb1 for 24 h and exposed to 400 µmol/l cobalt chloride (CoCl2) for 48 h or 600 µmol/l H2O2 for 24 h. The percentage of cells actively undergoing apoptosis was determined by flow cytometry with Annexin V/propidium iodide (PI) double staining. The expression of caspases was determined using western blot analysis. CoCl2 and H2O2 treatments significantly increased the apoptotic percentages to 24.5 and 21.63%, respectively. Pretreatment of Rb1 reduced the total apoptotic percentages to 15.12 and 12.03%, respectively. The expression of cleaved caspase-3, -9 and -8 was increased in the CoCl2-treated group, however, caspase-3 was not increased in the H2O2-treated group. Pretreatment of Rb1 reduced the expression of cleaved caspase-3 and -9 in the CoCl2-treated group, but reduced only cleaved caspase-9 in the H2O2-treated group. These results suggest that Rb1 may prevent RGC-5 cells from apoptosis against hypoxia and oxidative stress via the mitochondrial pathway.

  9. Structure and Function of Bistratified Intrinsically Photosensitive Retinal Ganglion Cells in the Mouse

    PubMed Central

    Schmidt, Tiffany M.; Kofuji, Paulo

    2013-01-01

    A subpopulation of retinal ganglion cells (RGCs) expresses the photopigment melanopsin, rendering these cells intrinsically photosensitive (ipRGCs). These cells are critical for competent circadian entrainment, pupillary light reflex, and other non-image-forming photic responses. Research has now demonstrated the presence of multiple subpopulations of ipRGC based on the dendritic stratification in the inner plexiform layer (IPL), those monostratified in the Off sublamina (M1), those monostratified in the On sublamina (M2,4,5), and those bistratified in both the On and Off sublaminas (M3). Despite evidence that M1 and M2 cells are distinct subpopulations of ipRGC based on distinct morphological and physiological properties, the inclusion of M3 cells as a distinct subtype has remained controversial. Aside from the identification of M3 cells as a morphological subpopulation of ipRGC, to date there have been no functional descriptions of M3 cell physiology or synaptic inputs. Our data provide the first in-depth description of M3 cell structural and functional properties. We report that M3 cells form a morphologically heterogeneous population, but one that is physiologically homogeneous with properties similar to those of M2 cells. PMID:21452206

  10. Dendritic Calcium Signaling in ON and OFF Mouse Retinal Ganglion Cells

    PubMed Central

    Margolis, David J.; Gartland, Andrew J.; Euler, Thomas; Detwiler, Peter B.

    2010-01-01

    Retinal ganglion cells (RGCs) are the output cells of the retina; they convert synaptic input into spike output that carries visual information to the brain. Synaptic inputs are received, integrated and communicated to the spike initiation zone of the axon by dendrites whose properties are poorly understood. Here simultaneous patch clamp recording and 2-photon Ca2+ imaging are used to study voltage- and light-evoked Ca2+ signals in the dendrites of identified types of mouse RGCs from parallel ON and OFF pathways, which encode the onset and offset of light, respectively. The results show pathway-specific differences in voltage-dependent Ca2+ signaling. While both ON and OFF cells express high-voltage-activated (HVA) Ca2+ channels, only OFF RGCs also express low-voltage-activated (LVA) Ca2+ channels. LVA Ca2+ channels in OFF cells are de-inactivated by hyperpolarization from the resting potential and give rise to rebound excited Ca2+ spikes at the termination of a step of either hyperpolarizing current or light. This suggests that the differential expression of voltage-gated Ca2+ channels in ON and OFF RGC dendrites contribute to differences in the way the two cell types process visual stimuli. PMID:20505081

  11. AVAILABILITY OF LOW-THRESHOLD Ca2+ CURRENT IN RETINAL GANGLION CELLS

    PubMed Central

    Lee, Sherwin C.; Hayashida, Yuki; Ishida, Andrew T.

    2011-01-01

    Spiking in central neurons depends on the availability of inward and outward currents activated by depolarization, and on the activation and priming of currents by hyperpolarization. Of these processes, priming by hyperpolarization is the least described. In the case of T-type Ca2+ current availability, the interplay of hyperpolarization and depolarization has been studied most completely in expression systems, in part because of the difficulty of pharmacologically separating the Ca2+ currents of native neurons. To facilitate understanding of this current under physiological conditions, we measured T-type current of isolated goldfish retinal ganglion cells with perforated-patch voltage clamp methods in solutions containing a normal extracellular Ca2+ concentration. The voltage-sensitivities and rates of current activation, inactivation, deactivation, and recovery from inactivation were similar to those of expressed α1G (CaV3.1) Ca2+ channel clones, except that the rate of deactivation was significantly faster. We reproduced the amplitude and kinetics of measured T currents with a numerical simulation based on a kinetic model developed for an α1G Ca2+ channel. Finally, we show that this model predicts the increase of T-type current made available between resting potential and spike threshold by repetitive hyperpolarizations presented at rates that are within the bandwidth of signals processed in situ by these neurons. PMID:14665686

  12. The effect of visual blue light on mitochondrial function associated with retinal ganglions cells.

    PubMed

    Osborne, Neville N; Núñez-Álvarez, Claudia; Del Olmo-Aguado, Susana

    2014-11-01

    The retina is the only part of the central nervous system that is exposed to light radiation between 400 and 780 nm. Short wavelength light (SWL) ranging between 400 and 480 nm are absorbed maximally by chromophores located in mitochondria. An abundance of mitochondria are located in retinal ganglion cell (RGC) intraocular axons and photoreceptor inner segments and as a consequence SWL will impact these organelles. The purpose of this article is to summarise the experimental evidence for the possible negative effects of SWL on RGC mitochondria, in situ. The threat of damage to photoreceptor mitochondria may be less than to RGCs, since macular carotenoid, located chiefly in Henle's layer of the photoreceptor inner segment absorbs SWL. The article underlines the hypothesis that SWL contributes to RGC death when these neurones are not in an optimum homoeostatic state as is likely to occur in conditions such as glaucoma and possibly other types of pathologies and even old age. A case therefore exists for the idea that shielding RGCs to slow down visual loss in certain circumstances. This can theoretically be achieved with lenses that reduce transmission of SWL but specifically allow for maximal transmission of 479 nm light to stimulate melanopsin and maintain an optimum sleep/wake cycle.

  13. BDNF injected into the superior colliculus reduces developmental retinal ganglion cell death.

    PubMed

    Ma, Y T; Hsieh, T; Forbes, M E; Johnson, J E; Frost, D O

    1998-03-15

    The role of neurotrophins as survival factors for developing CNS neurons, including retinal ganglion cells (RGCs), is uncertain. Null mutations for brain-derived neurotrophic factor (BDNF) or neurotrophin 4 (NT4), individually or together, are without apparent effect on the number of RGCs that survive beyond the period of normal, developmental RGC death. This contrasts with the BDNF dependence of RGCs in vitro and the effectiveness of BDNF in reducing RGC loss after axotomy. To investigate the effect of target-derived neurotrophins on the survival of developing RGCs, we injected BDNF into the superior colliculus (SC) of neonatal hamsters. At the age when the rate of developmental RGC death is greatest, BDNF produces, 20 hr after injection, a 13-15-fold reduction in the rate of RGC pyknosis compared with the rates in vehicle-injected and untreated hamsters. There is no effect 8 hr after injection. Electrochemiluminescence immunoassay measurements of BDNF protein in the retinae and SC of normal and BDNF-treated hamsters demonstrate that the time course of BDNF transport to RGCs supports a role for target-derived BDNF in promoting RGC survival. The effectiveness of pharmacological doses of BDNF in reducing developmental RGC death may be useful in further studies of the mechanisms of stabilization and elimination of immature central neurons.

  14. Differentiation of human ESCs to retinal ganglion cells using a CRISPR engineered reporter cell line

    PubMed Central

    Sluch, Valentin M.; Davis, Chung-ha O.; Ranganathan, Vinod; Kerr, Justin M.; Krick, Kellin; Martin, Russ; Berlinicke, Cynthia A.; Marsh-Armstrong, Nicholas; Diamond, Jeffrey S.; Mao, Hai-Quan; Zack, Donald J.

    2015-01-01

    Retinal ganglion cell (RGC) injury and cell death from glaucoma and other forms of optic nerve disease is a major cause of irreversible vision loss and blindness. Human pluripotent stem cell (hPSC)-derived RGCs could provide a source of cells for the development of novel therapeutic molecules as well as for potential cell-based therapies. In addition, such cells could provide insights into human RGC development, gene regulation, and neuronal biology. Here, we report a simple, adherent cell culture protocol for differentiation of hPSCs to RGCs using a CRISPR-engineered RGC fluorescent reporter stem cell line. Fluorescence-activated cell sorting of the differentiated cultures yields a highly purified population of cells that express a range of RGC-enriched markers and exhibit morphological and physiological properties typical of RGCs. Additionally, we demonstrate that aligned nanofiber matrices can be used to guide the axonal outgrowth of hPSC-derived RGCs for in vitro optic nerve-like modeling. Lastly, using this protocol we identified forskolin as a potent promoter of RGC differentiation. PMID:26563826

  15. The types of retinal ganglion cells: current status and implications for neuronal classification.

    PubMed

    Sanes, Joshua R; Masland, Richard H

    2015-07-08

    In the retina, photoreceptors pass visual information to interneurons, which process it and pass it to retinal ganglion cells (RGCs). Axons of RGCs then travel through the optic nerve, telling the rest of the brain all it will ever know about the visual world. Research over the past several decades has made clear that most RGCs are not merely light detectors, but rather feature detectors, which send a diverse set of parallel, highly processed images of the world on to higher centers. Here, we review progress in classification of RGCs by physiological, morphological, and molecular criteria, making a particular effort to distinguish those cell types that are definitive from those for which information is partial. We focus on the mouse, in which molecular and genetic methods are most advanced. We argue that there are around 30 RGC types and that we can now account for well over half of all RGCs. We also use RGCs to examine the general problem of neuronal classification, arguing that insights and methods from the retina can guide the classification enterprise in other brain regions.

  16. Nuclear translocation and overexpression of GAPDH by the hyper-pressure in retinal ganglion cell

    SciTech Connect

    Kim, Choong-Il; Lee, Sung-Ho; Seong, Gong-Je; Kim, Yeon-Hyang; Lee, Mi-Young . E-mail: miyoung@sch.ac.kr

    2006-03-24

    To investigate the effect of hyper-pressure on retinal ganglion cells (RGC-5), RGC-5 cells were exposed to an ambient hydrostatic pressure of 100 mm Hg. Upon treatment, the proliferation of RGC-5 cells was inhibited and neuronal apoptosis was detected by specific apoptosis marker TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling). To probe into the mechanism mediating the apoptosis of RGC-5 cells in 100 mm Hg, protein profile alterations following hyper-pressure treatment were examined using two-dimensional gel electrophoresis (2-DE) followed by MALDI-TOF. Out of the 400 protein spots of RGC-5 cells detected on 2-DE gels, 37 differentially expressed protein spots were further identified using in gel tryptic digestion and mass spectrometry. Among these proteins, glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) was significantly expressed 10 times more in 100 mm Hg than in normal pressure. The accumulation of GAPDH in the nucleus and its translocation from the cytosol to the nucleus in 100 mm Hg were observed using a microscope. These results suggest that the hyper-pressure-induced apoptosis in RGC-5 cells may be involved with not only the increase of GAPDH expression, but also the accumulation and the translocalization of GAPDH to the nucleus.

  17. Nerve growth factor protects against palmitic acid-induced injury in retinal ganglion cells

    PubMed Central

    Yan, Pan-shi; Tang, Shu; Zhang, Hai-feng; Guo, Yuan-yuan; Zeng, Zhi-wen; Wen, Qiang

    2016-01-01

    Accumulating evidence supports an important role for nerve growth factor (NGF) in diabetic retinopathy. We hypothesized that NGF has a protective effect on rat retinal ganglion RGC-5 cells injured by palmitic acid (PA), a metabolic factor implicated in the development of diabetes and its complications. Our results show that PA exposure caused apoptosis of RGC-5 cells, while NGF protected against PA insult in a concentration-dependent manner. Additionally, NGF significantly attenuated the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in RGC-5 cells. Pathway inhibitor tests showed that the protective effect of NGF was completely reversed by LY294002 (PI3K inhibitor), Akt VIII inhibitor, and PD98059 (ERK1/2 inhibitor). Western blot analysis revealed that NGF induced the phosphorylation of Akt/FoxO1 and ERK1/2 and reversed the PA-evoked reduction in the levels of these proteins. These results indicate that NGF protects RGC-5 cells against PA-induced injury through anti-oxidation and inhibition of apoptosis by modulation of the PI3K/Akt and ERK1/2 signaling pathways. PMID:28123432

  18. Endocannabinoid signaling enhances visual responses through modulation of intracellular chloride levels in retinal ganglion cells

    PubMed Central

    Miraucourt, Loïs S; Tsui, Jennifer; Gobert, Delphine; Desjardins, Jean-François; Schohl, Anne; Sild, Mari; Spratt, Perry; Castonguay, Annie; De Koninck, Yves; Marsh-Armstrong, Nicholas; Wiseman, Paul W; Ruthazer, Edward S

    2016-01-01

    Type 1 cannabinoid receptors (CB1Rs) are widely expressed in the vertebrate retina, but the role of endocannabinoids in vision is not fully understood. Here, we identified a novel mechanism underlying a CB1R-mediated increase in retinal ganglion cell (RGC) intrinsic excitability acting through AMPK-dependent inhibition of NKCC1 activity. Clomeleon imaging and patch clamp recordings revealed that inhibition of NKCC1 downstream of CB1R activation reduces intracellular Cl− levels in RGCs, hyperpolarizing the resting membrane potential. We confirmed that such hyperpolarization enhances RGC action potential firing in response to subsequent depolarization, consistent with the increased intrinsic excitability of RGCs observed with CB1R activation. Using a dot avoidance assay in freely swimming Xenopus tadpoles, we demonstrate that CB1R activation markedly improves visual contrast sensitivity under low-light conditions. These results highlight a role for endocannabinoids in vision and present a novel mechanism for cannabinoid modulation of neuronal activity through Cl− regulation. DOI: http://dx.doi.org/10.7554/eLife.15932.001 PMID:27501334

  19. Electrophysiological responses from intrinsically photosensitive retinal ganglion cells are diminished in glaucoma patients.

    PubMed

    Kuze, Manami; Morita, Takeshi; Fukuda, Yumi; Kondo, Mineo; Tsubota, Kazuo; Ayaki, Masahiko

    To record electroretinograms (ERGs) from intrinsically photosensitive retinal ganglion cells (ipRGCs) of glaucoma patients. ERGs were recorded in 10 normal subjects and 15 patients with glaucoma. The ERG illumination system was built to achieve receptor-silent substitution, and comprised an optical diffuser and four-in-one light-emitting diodes. The ERG recordings of ipRGC from normal subjects showed an "on" response and an "off" response. The mean (±SD) implicit time for the on and off responses in normal subjects was 103.0±24.9 and 337.9±45.8ms, respectively, with corresponding amplitudes of 7.7±2.8 and 7.3±3.4μV, respectively. In glaucoma patients, the implicit time of the on and off responses was 135.0±28.9 and 368.2±17.3ms, respectively. The corresponding amplitudes of the on and off responses in these patients were 0.47±0.18 and 0.66±0.32μV, respectively. The results demonstrate successful ERG recording of ipRGCs from advanced glaucoma patients, with marked reductions in amplitude, although not implicit time, compared with normal subjects. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  20. NF-Protocadherin Regulates Retinal Ganglion Cell Axon Behaviour in the Developing Visual System

    PubMed Central

    Leung, Louis C.; Harris, William A.; Holt, Christine E.; Piper, Michael

    2015-01-01

    Cell adhesion molecules play a central role in mediating axonal tract development within the nascent nervous system. NF-protocadherin (NFPC), a member of the non-clustered protocadherin family, has been shown to regulate retinal ganglion cell (RGC) axon and dendrite initiation, as well as influencing axonal navigation within the mid-optic tract. However, whether NFPC mediates RGC axonal behaviour at other positions within the optic pathway remains unclear. Here we report that NFPC plays an important role in RGC axonogenesis, but not in intraretinal guidance. Moreover, axons with reduced NFPC levels exhibit insensitivity to Netrin-1, an attractive guidance cue expressed at the optic nerve head. Netrin-1 induces rapid turnover of NFPC localized to RGC growth cones, suggesting that the regulation of NFPC protein levels may underlie Netrin-1-mediated entry of RGC axons into the optic nerve head. At the tectum, we further reveal a function for NFPC in controlling RGC axonal entry into the final target area. Collectively, our results expand our understanding of the role of NFPC in RGC guidance and illustrate that this adhesion molecule contributes to axon behaviour at multiple points in the optic pathway. PMID:26489017

  1. Connexin 36 and Rod Bipolar Cell Independent Rod Pathways Drive Retinal Ganglion Cells and Optokinetic Reflexes

    PubMed Central

    Cowan, Cameron S.; Abd-El-Barr, Muhammad; van der Heijden, Meike; Lo, Eric M.; Paul, David; Bramblett, Debra E.; Lem, Janis; Simons, David L.; Wu, Samuel M.

    2016-01-01

    Rod pathways are a parallel set of synaptic connections which enable night vision by relaying and processing rod photoreceptor light responses. We use dim light stimuli to isolate rod pathway contributions to downstream light responses then characterize these contributions in knockout mice lacking rod transducin-α (Trα), or certain pathway components associated with subsets of rod pathways. These comparisons reveal that rod pathway driven light sensitivity in retinal ganglion cells (RGCs) is entirely dependent on Trα, but partially independent of connexin 36 (Cx36) and rod bipolar cells. Pharmacological experiments show that rod pathway-driven and Cx36-independent RGC ON responses are also metabotropic glutamate receptor 6-dependent. To validate the RGC findings in awake, behaving animals we measured optokinetic reflexes (OKRs), which are sensitive to changes in ON pathways. Scotopic OKR contrast sensitivity was lost in Trα−/− mice, but indistinguishable from controls in Cx36−/− and rod bipolar cell knockout mice. Mesopic OKRs were also altered in mutant mice: Trα−/− mice had decreased spatial acuity, rod BC knockouts had decreased sensitivity, and Cx36−/− mice had increased sensitivity. These results provide compelling evidence against the complete Cx36 or rod BC dependence of night vision's ON component. Further, the findings suggest the parallel nature of rod pathways provides considerable redundancy to scotopic light sensitivity but distinct contributions to mesopic responses through complicated interactions with cone pathways. PMID:26718442

  2. Characterization of an Early-Onset, Autosomal Recessive, Progressive Retinal Degeneration in Bengal Cats

    PubMed Central

    Ofri, Ron; Reilly, Christopher M.; Maggs, David J.; Fitzgerald, Paul G.; Shilo-Benjamini, Yael; Good, Kathryn L.; Grahn, Robert A.; Splawski, Danielle D.; Lyons, Leslie A.

    2015-01-01

    Purpose A form of retinal degeneration suspected to be hereditary was discovered in a family of Bengal cats. A breeding colony was established to characterize disease progression clinically, electrophysiologically, and morphologically, and to investigate the mode of inheritance. Methods Affected and related cats were donated by owners for breeding trials and pedigree analysis. Kittens from test and complementation breedings underwent ophthalmic and neuro-ophthalmic examinations and ERG, and globes were evaluated using light microscopy. Results Pedigree analysis, along with test and complementation breedings, indicated autosomal recessive inheritance and suggested that this disease is nonallelic to a retinal degeneration found in Persian cats. Mutation analysis confirmed the disease is not caused by CEP290 or CRX variants found predominantly in Abyssinian and Siamese cats. Ophthalmoscopic signs of retinal degeneration were noted at 9 weeks of age and became more noticeable over the next 4 months. Visual deficits were behaviorally evident by 1 year of age. Electroretinogram demonstrated reduced rod and cone function at 7 and 9 weeks of age, respectively. Rod responses were mostly extinguished at 14 weeks of age; cone responses were minimal by 26 weeks. Histologic degeneration was first observed at 8 weeks, evidenced by reduced photoreceptor numbers, then rapid deterioration of the photoreceptor layer and, subsequently, severe outer retinal degeneration. Conclusions A recessively inherited primary photoreceptor degeneration was characterized in the Bengal cat. The disease is characterized by early onset, with histologic, ophthalmoscopic, and electrophysiological signs evident by 2 months of age, and rapid progression to blindness. PMID:26258614

  3. Genome-wide association and linkage analyses localize a progressive retinal atrophy locus in Persian cats.

    PubMed

    Alhaddad, Hasan; Gandolfi, Barbara; Grahn, Robert A; Rah, Hyung-Chul; Peterson, Carlyn B; Maggs, David J; Good, Kathryn L; Pedersen, Niels C; Lyons, Leslie A

    2014-08-01

    Hereditary eye diseases of animals serve as excellent models of human ocular disorders and assist in the development of gene and drug therapies for inherited forms of blindness. Several primary hereditary eye conditions affecting various ocular tissues and having different rates of progression have been documented in domestic cats. Gene therapy for canine retinopathies has been successful, thus the cat could be a gene therapy candidate for other forms of retinal degenerations. The current study investigates a hereditary, autosomal recessive, retinal degeneration specific to Persian cats. A multi-generational pedigree segregating for this progressive retinal atrophy was genotyped using a 63 K SNP array and analyzed via genome-wide linkage and association methods. A multi-point parametric linkage analysis localized the blindness phenotype to a ~1.75 Mb region with significant LOD scores (Z ≈ 14, θ = 0.00) on cat chromosome E1. Genome-wide TDT, sib-TDT, and case-control analyses also consistently supported significant association within the same region on chromosome E1, which is homologous to human chromosome 17. Using haplotype analysis, a ~1.3 Mb region was identified as highly associated for progressive retinal atrophy in Persian cats. Several candidate genes within the region are reasonable candidates as a potential causative gene and should be considered for molecular analyses.

  4. Selective Vulnerability of Specific Retinal Ganglion Cell Types and Synapses after Transient Ocular Hypertension

    PubMed Central

    Jo, Rebecca E.; Ullian, Erik M.; Wong, Rachel O.L.

    2016-01-01

    Key issues concerning ganglion cell type-specific loss and synaptic changes in animal models of experimental glaucoma remain highly debated. Importantly, changes in the structure and function of various RGC types that occur early, within 14 d after acute, transient intraocular pressure elevation, have not been previously assessed. Using biolistic transfection of individual RGCs and multielectrode array recordings to measure light responses in mice, we examined the effects of laser-induced ocular hypertension on the structure and function of a subset of RGCs. Among the α-like RGCs studied, αOFF-transient RGCs exhibited higher rates of cell death, with corresponding reductions in dendritic area, dendritic complexity, and synapse density. Functionally, OFF-transient RGCs displayed decreases in spontaneous activity and receptive field size. In contrast, neither αOFF-sustained nor αON-sustained RGCs displayed decreases in light responses, although they did exhibit a decrease in excitatory postsynaptic sites, suggesting that synapse loss may be one of the earliest signs of degeneration. Interestingly, presynaptic ribbon density decreased to a greater degree in the OFF sublamina of the inner plexiform layer, corroborating the hypothesis that RGCs with dendrites stratifying in the OFF sublamina may be damaged early. Indeed, OFF arbors of ON-OFF RGCs lose complexity more rapidly than ON arbors. Our results reveal type-specific differences in RGC responses to injury with a selective vulnerability of αOFF-transient RGCs, and furthermore, an increased susceptibility of synapses in the OFF sublamina. The selective vulnerability of specific RGC types offers new avenues for the design of more sensitive functional tests and targeted neuroprotection. SIGNIFICANCE STATEMENT Conflicting reports regarding the selective vulnerability of specific retinal ganglion cell (RGC) types in glaucoma exist. We examine, for the first time, the effects of transient intraocular pressure

  5. Asymmetric inheritance of the apical domain and self-renewal of retinal ganglion cell progenitors depend on Anillin function.

    PubMed

    Paolini, Alessio; Duchemin, Anne-Laure; Albadri, Shahad; Patzel, Eva; Bornhorst, Dorothee; González Avalos, Paula; Lemke, Steffen; Machate, Anja; Brand, Michael; Sel, Saadettin; Di Donato, Vincenzo; Del Bene, Filippo; Zolessi, Flavio R; Ramialison, Mirana; Poggi, Lucia

    2015-03-01

    Divisions that generate one neuronal lineage-committed and one self-renewing cell maintain the balance of proliferation and differentiation for the generation of neuronal diversity. The asymmetric inheritance of apical domains and components of the cell division machinery has been implicated in this process, and might involve interactions with cell fate determinants in regulatory feedback loops of an as yet unknown nature. Here, we report the dynamics of Anillin - an essential F-actin regulator and furrow component - and its contribution to progenitor cell divisions in the developing zebrafish retina. We find that asymmetrically dividing retinal ganglion cell progenitors position the Anillin-rich midbody at the apical domain of the differentiating daughter. anillin hypomorphic conditions disrupt asymmetric apical domain inheritance and affect daughter cell fate. Consequently, the retinal cell type composition is profoundly affected, such that the ganglion cell layer is dramatically expanded. This study provides the first in vivo evidence for the requirement of Anillin during asymmetric neurogenic divisions. It also provides insights into a reciprocal regulation between Anillin and the ganglion cell fate determinant Ath5, suggesting a mechanism whereby the balance of proliferation and differentiation is accomplished during progenitor cell divisions in vivo.

  6. Activation of the ζ receptor 1 suppresses NMDA responses in rat retinal ganglion cells.

    PubMed

    Zhang, X-J; Liu, L-L; Jiang, S-X; Zhong, Y-M; Yang, X-L

    2011-03-17

    The sigma receptor 1 (σR1) has been shown to modulate the activity of several voltage- and ligand-gated channels. Using patch-clamp techniques in rat retinal slice preparations, we demonstrated that activation of σR1 by SKF10047 (SKF) or PRE-084 suppressed N-methyl-D-aspartate (NMDA) receptor-mediated current responses from both ON and OFF type ganglion cells (GCs), dose-dependently, and the effect could be blocked by the σR1 antagonist BD1047 or the σR antagonist haloperidol. The suppression by SKF of NMDA currents was abolished with pre-incubation of the G protein inhibitor GDP-β-S or the Gi/o activator mastoparan. We further explored the intracellular signaling pathway responsible for the SKF-induced suppression of NMDA responses. Application of either cAMP/the PKA inhibitor Rp-cAMP or cGMP/the PKG inhibitor KT5823 did not change the SKF-induced effect, suggesting the involvement of neither cAMP/PKA nor cGMP/PKG pathway. In contrast, suppression of NMDA responses by SKF was abolished by internal infusion of the phosphatidylinostiol-specific phospholipase C (PLC) inhibitor U73122, but not by the phosphatidylcholine-PLC inhibitor D609. SKF-induced suppression of NMDA responses was dependent on intracellular Ca2+ concentration ([Ca2+]i), as evidenced by the fact that the effect was abolished when [Ca2+]i was buffered with 10 mM BAPTA. The SKF effect was blocked by xestospongin-C/heparin, IP3 receptor antagonists, but unchanged by ryanodine/caffeine, ryanodine receptor modulators. Furthermore, application of protein kinase C inhibitors Bis IV and Gö6976 eliminated the SKF effect. These results suggest that the suppression of NMDA responses of rat retinal GCs caused by the activation of σR1 may be mediated by a distinct [Ca2+]i-dependent PLC-PKC pathway. This effect of SKF could help ameliorate malfunction of GCs caused by excessive stimulation of NMDA receptors under pathological conditions.

  7. Orexin-A potentiates L-type calcium/barium currents in rat retinal ganglion cells.

    PubMed

    Liu, F; Weng, S-J; Yang, X-L; Zhong, Y-M

    2015-10-01

    Two neuropeptides, orexin-A and orexin-B (also called hypocretin-1 and -2), have been implicated in sleep/wake regulation, feeding behaviors via the activation of two subtypes of G-protein-coupled receptors: orexin 1 and orexin 2 receptors (OX1R and OX2R). While the expression of orexins and orexin receptors is immunohistochemically revealed in retinal neurons, the function of these peptides in the retina is largely unknown. Using whole-cell patch-clamp recordings in rat retinal slices, we demonstrated that orexin-A increased L-type-like barium currents (IBa,L) in ganglion cells (GCs), and the effect was blocked by the selective OX1R antagonist SB334867, but not by the OX2R antagonist TCS OX2 29. The orexin-A effect was abolished by intracellular dialysis of GDP-β-S/GPAnt-2A, a Gq protein inhibitor, suggesting the mediation of Gq. Additionally, during internal dialysis of the phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor U73122, orexin-A did not change the IBa,L of GCs, whereas the orexin-A effect persisted in the presence of the phosphatidylcholine (PC)-PLC inhibitor D609. The orexin-A-induced potentiation was not seen with internal infusion of Ca(2+)-free solution or when inositol 1,4,5-trisphosphate (IP3)-sensitive Ca(2+) release from intracellular stores was blocked by heparin/xestospongins-C. Moreover, the orexin-A effect was mimicked by the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate, but was eliminated when PKC was inhibited by bisindolylmaleimide IV (Bis-IV)/Gö6976. Neither adenosine 3',5'-cyclic monophosphate (cAMP)-protein kinase A (PKA) nor guanosine 3',5'-cyclic monophosphate (cGMP)-protein kinase G (PKG) signaling pathway was likely involved, as orexin-A persisted to potentiate the IBa,L of GCs no matter these two pathways were activated or inhibited. These results suggest that, by activating OX1R, orexin-A potentiates the IBa,L of rat GCs through a distinct Gq/PI-PLC/IP3/Ca(2+)/PKC signaling pathway.

  8. Mechanisms creating transient and sustained photoresponses in mammalian retinal ganglion cells.

    PubMed

    Zhao, Xiwu; Reifler, Aaron N; Schroeder, Melanie M; Jaeckel, Elizabeth R; Chervenak, Andrew P; Wong, Kwoon Y

    2017-03-06

    Retinal neurons use sustained and transient light responses to encode visual stimuli of different frequency ranges, but the underlying mechanisms remain poorly understood. In particular, although earlier studies in retinal ganglion cells (RGCs) proposed seven potential mechanisms, all seven have since been disputed, and it remains unknown whether different RGC types use different mechanisms or how many mechanisms are used by each type. Here, we conduct a comprehensive survey in mice and rats of 12 candidate mechanisms that could conceivably produce tonic rod/cone-driven ON responses in intrinsically photosensitive RGCs (ipRGCs) and transient ON responses in three types of direction-selective RGCs (TRHR+, Hoxd10+ ON, and Hoxd10+ ON-OFF cells). We find that the tonic kinetics of ipRGCs arises from their substantially above-threshold resting potentials, input from sustained ON bipolar cells, absence of amacrine cell inhibition of presynaptic ON bipolar cells, and mGluR7-mediated maintenance of light-evoked glutamatergic input. All three types of direction-selective RGCs receive input from transient ON bipolar cells, and each type uses additional strategies to promote photoresponse transience: presynaptic inhibition and dopaminergic modulation for TRHR+ cells, center/surround antagonism and relatively negative resting potentials for Hoxd10+ ON cells, and presynaptic inhibition for Hoxd10+ ON-OFF cells. We find that the sustained nature of ipRGCs' rod/cone-driven responses depends neither on melanopsin nor on N-methyl-d-aspartate (NMDA) receptors, whereas the transience of the direction-selective cells' responses is influenced neither by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor desensitization nor by glutamate uptake. For all cells, we further rule out spike frequency adaptation and intracellular Ca(2+) as determinants of photoresponse kinetics. In conclusion, different RGC types use diverse mechanisms to produce sustained or

  9. Hydrostatic Pressure Does Not Cause Detectable Changes in Survival of Human Retinal Ganglion Cells

    PubMed Central

    Osborne, Andrew; Aldarwesh, Amal; Rhodes, Jeremy D.; Broadway, David C.; Everitt, Claire; Sanderson, Julie

    2015-01-01

    Purpose Elevated intraocular pressure (IOP) is a major risk factor for glaucoma. One consequence of raised IOP is that ocular tissues are subjected to increased hydrostatic pressure (HP). The effect of raised HP on stress pathway signaling and retinal ganglion cell (RGC) survival in the human retina was investigated. Methods A chamber was designed to expose cells to increased HP (constant and fluctuating). Accurate pressure control (10-100mmHg) was achieved using mass flow controllers. Human organotypic retinal cultures (HORCs) from donor eyes (<24h post mortem) were cultured in serum-free DMEM/HamF12. Increased HP was compared to simulated ischemia (oxygen glucose deprivation, OGD). Cell death and apoptosis were measured by LDH and TUNEL assays, RGC marker expression by qRT-PCR (THY-1) and RGC number by immunohistochemistry (NeuN). Activated p38 and JNK were detected by Western blot. Results Exposure of HORCs to constant (60mmHg) or fluctuating (10-100mmHg; 1 cycle/min) pressure for 24 or 48h caused no loss of structural integrity, LDH release, decrease in RGC marker expression (THY-1) or loss of RGCs compared with controls. In addition, there was no increase in TUNEL-positive NeuN-labelled cells at either time-point indicating no increase in apoptosis of RGCs. OGD increased apoptosis, reduced RGC marker expression and RGC number and caused elevated LDH release at 24h. p38 and JNK phosphorylation remained unchanged in HORCs exposed to fluctuating pressure (10-100mmHg; 1 cycle/min) for 15, 30, 60 and 90min durations, whereas OGD (3h) increased activation of p38 and JNK, remaining elevated for 90min post-OGD. Conclusions Directly applied HP had no detectable impact on RGC survival and stress-signalling in HORCs. Simulated ischemia, however, activated stress pathways and caused RGC death. These results show that direct HP does not cause degeneration of RGCs in the ex vivo human retina. PMID:25635827

  10. Hydrostatic pressure does not cause detectable changes in survival of human retinal ganglion cells.

    PubMed

    Osborne, Andrew; Aldarwesh, Amal; Rhodes, Jeremy D; Broadway, David C; Everitt, Claire; Sanderson, Julie

    2015-01-01

    Elevated intraocular pressure (IOP) is a major risk factor for glaucoma. One consequence of raised IOP is that ocular tissues are subjected to increased hydrostatic pressure (HP). The effect of raised HP on stress pathway signaling and retinal ganglion cell (RGC) survival in the human retina was investigated. A chamber was designed to expose cells to increased HP (constant and fluctuating). Accurate pressure control (10-100 mmHg) was achieved using mass flow controllers. Human organotypic retinal cultures (HORCs) from donor eyes (<24 h post mortem) were cultured in serum-free DMEM/HamF12. Increased HP was compared to simulated ischemia (oxygen glucose deprivation, OGD). Cell death and apoptosis were measured by LDH and TUNEL assays, RGC marker expression by qRT-PCR (THY-1) and RGC number by immunohistochemistry (NeuN). Activated p38 and JNK were detected by Western blot. Exposure of HORCs to constant (60 mmHg) or fluctuating (10-100 mmHg; 1 cycle/min) pressure for 24 or 48 h caused no loss of structural integrity, LDH release, decrease in RGC marker expression (THY-1) or loss of RGCs compared with controls. In addition, there was no increase in TUNEL-positive NeuN-labelled cells at either time-point indicating no increase in apoptosis of RGCs. OGD increased apoptosis, reduced RGC marker expression and RGC number and caused elevated LDH release at 24 h. p38 and JNK phosphorylation remained unchanged in HORCs exposed to fluctuating pressure (10-100 mmHg; 1 cycle/min) for 15, 30, 60 and 90 min durations, whereas OGD (3 h) increased activation of p38 and JNK, remaining elevated for 90 min post-OGD. Directly applied HP had no detectable impact on RGC survival and stress-signalling in HORCs. Simulated ischemia, however, activated stress pathways and caused RGC death. These results show that direct HP does not cause degeneration of RGCs in the ex vivo human retina.

  11. Mechanisms creating transient and sustained photoresponses in mammalian retinal ganglion cells

    PubMed Central

    Zhao, Xiwu; Jaeckel, Elizabeth R.; Chervenak, Andrew P.

    2017-01-01

    Retinal neurons use sustained and transient light responses to encode visual stimuli of different frequency ranges, but the underlying mechanisms remain poorly understood. In particular, although earlier studies in retinal ganglion cells (RGCs) proposed seven potential mechanisms, all seven have since been disputed, and it remains unknown whether different RGC types use different mechanisms or how many mechanisms are used by each type. Here, we conduct a comprehensive survey in mice and rats of 12 candidate mechanisms that could conceivably produce tonic rod/cone-driven ON responses in intrinsically photosensitive RGCs (ipRGCs) and transient ON responses in three types of direction-selective RGCs (TRHR+, Hoxd10+ ON, and Hoxd10+ ON-OFF cells). We find that the tonic kinetics of ipRGCs arises from their substantially above-threshold resting potentials, input from sustained ON bipolar cells, absence of amacrine cell inhibition of presynaptic ON bipolar cells, and mGluR7-mediated maintenance of light-evoked glutamatergic input. All three types of direction-selective RGCs receive input from transient ON bipolar cells, and each type uses additional strategies to promote photoresponse transience: presynaptic inhibition and dopaminergic modulation for TRHR+ cells, center/surround antagonism and relatively negative resting potentials for Hoxd10+ ON cells, and presynaptic inhibition for Hoxd10+ ON-OFF cells. We find that the sustained nature of ipRGCs’ rod/cone-driven responses depends neither on melanopsin nor on N-methyl-d-aspartate (NMDA) receptors, whereas the transience of the direction-selective cells’ responses is influenced neither by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor desensitization nor by glutamate uptake. For all cells, we further rule out spike frequency adaptation and intracellular Ca2+ as determinants of photoresponse kinetics. In conclusion, different RGC types use diverse mechanisms to produce sustained or

  12. Astaxanthin attenuates the apoptosis of retinal ganglion cells in db/db mice by inhibition of oxidative stress.

    PubMed

    Dong, Ling-Yan; Jin, Jie; Lu, Gao; Kang, Xiao-Li

    2013-03-21

    Diabetic retinopathy is a common diabetic eye disease caused by changes in retinal ganglion cells (RGCs). It is an ocular manifestation of systemic disease, which affects up to 80% of all patients who have had diabetes for 10 years or more. The genetically diabetic db/db mouse, as a model of type-2 diabetes, shows diabetic retinopathy induced by apoptosis of RGCs. Astaxanthin is a carotenoid with powerful antioxidant properties that exists naturally in various plants, algae and seafood. Here, astaxanthin was shown to reduce the apoptosis of RGCs and improve the levels of oxidative stress markers, including superoxide anion, malondialdehyde (MDA, a marker of lipid peroxidation), 8-hydroxy-2-deoxyguanosine (8-OHdG, indicator of oxidative DNA damage) and MnSOD (manganese superoxide dismutase) activity in the retinal tissue of db/db mouse. In addition, astaxanthin attenuated hydrogen peroxide(H2O2)-induced apoptosis in the transformed rat retinal ganglion cell line RGC-5. Therefore, astaxanthin may be developed as an antioxidant drug to treat diabetic retinopathy.

  13. Co-Expression of Two Subtypes of Melatonin Receptor on Rat M1-Type Intrinsically Photosensitive Retinal Ganglion Cells

    PubMed Central

    Sheng, Wen-Long; Chen, Wei-Yi; Yang, Xiong-Li; Zhong, Yong-Mei; Weng, Shi-Jun

    2015-01-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) are involved in circadian and other non-image forming visual responses. An open question is whether the activity of these neurons may also be under the regulation mediated by the neurohormone melatonin. In the present work, by double-staining immunohistochemical technique, we studied the expression of MT1 and MT2, two known subtypes of mammalian melatonin receptors, in rat ipRGCs. A single subset of retinal ganglion cells labeled by the specific antibody against melanopsin exhibited the morphology typical of M1-type ipRGCs. Immunoreactivity for both MT1 and MT2 receptors was clearly seen in the cytoplasm of all labeled ipRGCs, indicating that these two receptors were co-expressed in each of these neurons. Furthermore, labeling for both the receptors were found in neonatal M1 cells as early as the day of birth. It is therefore highly plausible that retinal melatonin may directly modulate the activity of ipRGCs, thus regulating non-image forming visual functions. PMID:25714375

  14. Retinal Ganglion Cells and Circadian Rhythms in Alzheimer’s Disease, Parkinson’s Disease, and Beyond

    PubMed Central

    La Morgia, Chiara; Ross-Cisneros, Fred N.; Sadun, Alfredo A.; Carelli, Valerio

    2017-01-01

    There is increasing awareness on the role played by circadian rhythm abnormalities in neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). The characterization of the circadian dysfunction parallels the mounting evidence that the hallmarks of neurodegeneration also affect the retina and frequently lead to loss of retinal ganglion cells (RGCs) and to different degrees of optic neuropathy. In the RGC population, there is the subgroup of cells intrinsically photosensitive and expressing the photopigment melanopsin [melanopsin-containing retinal ganglion cells (mRGCs)], which are now well known to drive the entrainment of circadian rhythms to the light–dark cycles. Thus, the correlation between the pathological changes affecting the retina and mRGCs with the circadian imbalance in these neurodegenerative diseases is now clearly emerging, pointing to the possibility that these patients might be amenable to and benefit from light therapy. Currently, this connection is better established for AD and PD, but the same scenario may apply to other neurodegenerative disorders, such as Huntington’s disease. This review highlights similarities and differences in the retinal/circadian rhythm axis in these neurodegenerative diseases posing a working frame for future studies. PMID:28522986

  15. N-type and L-type calcium channels mediate glycinergic synaptic inputs to retinal ganglion cells of tiger salamanders.

    PubMed

    Bieda, Mark C; Copenhagen, David R

    2004-01-01

    Synaptically localized calcium channels shape the timecourse of synaptic release, are a prominent site for neuromodulation, and have been implicated in genetic disease. In retina, it is well established that L-type calcium channels play a major role in mediating release of glutamate from the photoreceptors and bipolar cells. However, little is known about which calcium channels are coupled to synaptic exocytosis of glycine, which is primarily released by amacrine cells. A recent report indicates that glycine release from spiking AII amacrine cells relies exclusively upon L-type calcium channels. To identify calcium channel types controlling neurotransmitter release from the population of glycinergic neurons that drive retinal ganglion cells, we recorded electrical and potassium evoked inhibitory synaptic currents (IPSCs) from these postsynaptic neurons in retinal slices from tiger salamanders. The L-channel antagonist nifedipine strongly inhibited release and FPL64176, an L-channel agonist, greatly enhanced it, indicating a significant role for L-channels. omega-Conotoxin MVIIC, an N/P/Q-channel antagonist, strongly inhibited release, indicating an important role for non-L channels. While the P/Q-channel blocker omega-Aga IVA produced only small effects, the N-channel blocker omega-conotoxin GVIA strongly inhibited release. Hence, N-type and L-type calcium channels appear to play major roles, overall, in mediating synaptic release of glycine onto retinal ganglion cells.

  16. Astaxanthin Attenuates the Apoptosis of Retinal Ganglion Cells in db/db Mice by Inhibition of Oxidative Stress

    PubMed Central

    Dong, Ling-Yan; Jin, Jie; Lu, Gao; Kang, Xiao-Li

    2013-01-01

    Diabetic retinopathy is a common diabetic eye disease caused by changes in retinal ganglion cells (RGCs). It is an ocular manifestation of systemic disease, which affects up to 80% of all patients who have had diabetes for 10 years or more. The genetically diabetic db/db mouse, as a model of type-2 diabetes, shows diabetic retinopathy induced by apoptosis of RGCs. Astaxanthin is a carotenoid with powerful antioxidant properties that exists naturally in various plants, algae and seafood. Here, astaxanthin was shown to reduce the apoptosis of RGCs and improve the levels of oxidative stress markers, including superoxide anion, malondialdehyde (MDA, a marker of lipid peroxidation), 8-hydroxy-2-deoxyguanosine (8-OHdG, indicator of oxidative DNA damage) and MnSOD (manganese superoxide dismutase) activity in the retinal tissue of db/db mouse. In addition, astaxanthin attenuated hydrogen peroxide(H2O2)-induced apoptosis in the transformed rat retinal ganglion cell line RGC-5. Therefore, astaxanthin may be developed as an antioxidant drug to treat diabetic retinopathy. PMID:23519150

  17. Involvement of Fra-1 in Retinal Ganglion Cell Apoptosis in Rat Light-Induced Retina Damage Model.

    PubMed

    Liu, Xiaojuan; Yang, Xiaowei; Zhu, Rongrong; Dai, Ming; Zhu, Manhui; Shen, Yuntian; Fang, Hongda; Sang, Aimin; Chen, Hui

    2017-01-01

    Cell cycle re-entry, in which Fra-1 (transcription factor FOS-related antigen 1) plays an important role, is a key process in neuronal apoptosis. However, the expression and function of Fra-1 in retinal ganglion cell (RGC) apoptosis are unknown. To investigate whether Fra-1 was involved in RGC apoptosis, we performed a light-induced retinal damage model in adult rats. Western blot revealed that up-regulation of Fra-1 expression appeared in retina after light exposure (LE). Immunostaining indicated that increased Fra-1 was mainly expressed in RGCs in retinal ganglion cell layer (GCL) after LE. Co-localization of Fra-1 with active caspase-3 or TUNEL-positive cells in GCL after LE was also detected. In addition, Fra-1 expression increased in parallel with cyclin D1 and phosphorylated mitogen-activated protein kinase p38 (p-p38) expression in retina after LE. Furthermore, Fra-1, cyclin D1, and active caspase-3 protein expression decreased by intravitreal injection of SB203580, a highly selective inhibitor of p38 MAP kinase (p38 MAPK). All these results suggested that Fra-1 may be associated with RGC apoptosis after LE regulated by p38 MAPK through cell cycle re-entry mechanism.

  18. Early regenerative responses induced by monoclonal antibodies directed against a surface glycoprotein of goldfish retinal ganglion cells.

    PubMed Central

    Schwartz, M; Eshhar, N

    1984-01-01

    Monoclonal antibodies directed primarily against antigenic determinants associated with the goldfish optic nerve were prepared and characterized. One selected clone 23-4-C(IgG2a), detected antigenic determinants of glycoprotein nature with an apparent mol. wt. of 140 000. Following injury the level of these molecules increased with a peak at 5-7 days after the lesion (2- to 3-fold higher than the basal level). The results strongly suggest that the increase derives, at least partially, from a real increment in the level of these molecules in the retinal ganglion cells rather than from changes in accessibility. Immunofluorescence studies indicate that the retinal ganglion cells carry the antigenicity. Intraocular injection of the monoclonal antibodies, concomitantly with crush injury, resulted in an earlier and higher regenerative response, reflected by sprouting capacity, protein synthesis and accumulation of radiolabeled material in the tectum contralateral to the side of injury. This may indicate that the antibodies directly activate retinal cells via interaction with surface molecules. Alternatively, the antibodies may be directed against surface molecules which are associated with axonal growth inhibitors, and may therefore mask these surface antigens from further interaction with their native substrate. Images Fig. 4. Fig. 5. Fig. 7. PMID:6204857

  19. Retinal Ganglion Cell Loss and Mild Vasculopathy in Methylene Tetrahydrofolate Reductase (Mthfr)-Deficient Mice: A Model of Mild Hyperhomocysteinemia.

    PubMed

    Markand, Shanu; Saul, Alan; Roon, Penny; Prasad, Puttur; Martin, Pamela; Rozen, Rima; Ganapathy, Vadivel; Smith, Sylvia B

    2015-04-01

    Methylenetetrahydrofolate reductase (Mthfr) is a key enzyme in homocysteine-methionine metabolism. We investigated Mthfr expression in retina and asked whether mild hyperhomocysteinemia, due to Mthfr deficiency, alters retinal neurovascular structure and function. Expression of Mthfr was investigated at the gene and protein level using quantitative (q) RT-PCR, in situ hybridization, immunoblotting, and immunohistochemistry (IHC). The Mthfr+/+ and Mthfr+/- mice were subjected to comprehensive evaluation using ERG, funduscopy, fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), HPLC, and morphometric and IHC analysis of glial fibrillary acidic protein (GFAP) at 8 to 24 weeks. Gene and protein analyses disclosed widespread retinal expression of Mthfr. Electroretinography (ERG) revealed a significant decrease in positive scotopic threshold response in retinas of Mthfr+/- mice at 24 weeks. Fundus examination in mice from both groups was normal; FA revealed areas of focal vascular leakage in 20% of Mthfr+/- mice at 12 to 16 weeks and 60% by 24 weeks. The SD-OCT revealed a significant decrease in nerve fiber layer (NFL) thickness at 24 weeks in Mthfr+/- compared to Mthfr+/+ mice. There was a 2-fold elevation in retinal hcy at 24 weeks in Mthfr+/- mice by HPLC and IHC. Morphometric analysis revealed an approximately 20% reduction in cells in the ganglion cell layer of Mthfr+/- mice at 24 weeks. The IHC indicated significantly increased GFAP labeling suggestive of Müller cell activation. Mildly hyperhomocysteinemic Mthfr+/- mice demonstrate reduced ganglion cell function, thinner NFL, and mild vasculopathy by 24 weeks. The retinal phenotype is similar to that of hyperhomocysteinemic mice with deficiency of cystathionine-β-synthase (Cbs) reported earlier. The data support the hypothesis that hyperhomocysteinemia may be causative in certain retinal neurovasculopathies.

  20. Retinal Ganglion Cell Loss and Mild Vasculopathy in Methylene Tetrahydrofolate Reductase (Mthfr)-Deficient Mice: A Model of Mild Hyperhomocysteinemia

    PubMed Central

    Markand, Shanu; Saul, Alan; Roon, Penny; Prasad, Puttur; Martin, Pamela; Rozen, Rima; Ganapathy, Vadivel; Smith, Sylvia B.

    2015-01-01

    Purpose. Methylenetetrahydrofolate reductase (Mthfr) is a key enzyme in homocysteine-methionine metabolism. We investigated Mthfr expression in retina and asked whether mild hyperhomocysteinemia, due to Mthfr deficiency, alters retinal neurovascular structure and function. Methods. Expression of Mthfr was investigated at the gene and protein level using quantitative (q) RT-PCR, in situ hybridization, immunoblotting, and immunohistochemistry (IHC). The Mthfr+/+ and Mthfr+/− mice were subjected to comprehensive evaluation using ERG, funduscopy, fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), HPLC, and morphometric and IHC analysis of glial fibrillary acidic protein (GFAP) at 8 to 24 weeks. Results. Gene and protein analyses disclosed widespread retinal expression of Mthfr. Electroretinography (ERG) revealed a significant decrease in positive scotopic threshold response in retinas of Mthfr+/− mice at 24 weeks. Fundus examination in mice from both groups was normal; FA revealed areas of focal vascular leakage in 20% of Mthfr+/− mice at 12 to 16 weeks and 60% by 24 weeks. The SD-OCT revealed a significant decrease in nerve fiber layer (NFL) thickness at 24 weeks in Mthfr+/− compared to Mthfr+/+ mice. There was a 2-fold elevation in retinal hcy at 24 weeks in Mthfr+/− mice by HPLC and IHC. Morphometric analysis revealed an approximately 20% reduction in cells in the ganglion cell layer of Mthfr+/− mice at 24 weeks. The IHC indicated significantly increased GFAP labeling suggestive of Müller cell activation. Conclusions. Mildly hyperhomocysteinemic Mthfr+/− mice demonstrate reduced ganglion cell function, thinner NFL, and mild vasculopathy by 24 weeks. The retinal phenotype is similar to that of hyperhomocysteinemic mice with deficiency of cystathionine-β-synthase (Cbs) reported earlier. The data support the hypothesis that hyperhomocysteinemia may be causative in certain retinal neurovasculopathies. PMID:25766590

  1. Erythropoietin (EPO) protects against high glucose-induced apoptosis in retinal ganglional cells.

    PubMed

    Wang, Yunxiao; Zhang, Hui; Liu, Yanping; Li, Ping; Cao, Zhihong; Cao, Yu

    2015-03-01

    The aim of this study was to investigate the protective effect and mechanism of EPO on the apoptosis induced by high levels of glucose in retinal ganglial cells (RGCs). High glucose-induced apoptosis model was established in RGCs isolated from SD rats (1-3 days old) and identified with Thy1.1 mAb and MAP-2 pAb. The apoptosis was determined by Hochest assay. The levels of ROS were quantitated by staining the cells with dichloro-dihydro-fluorescein diacetate (DCFH-DA) and measure by flow cytometry. The SOD, GSH-Px, CAT activities, and levels of T-AOC and MDA were determined by ELISA. Change in mitochondrial membrane potential (Δψm) was also assessed by flow cytometry, and expressions of Bcl-2, Bax, caspase-3, caspase-9, and cytochrome C were assessed by western blotting. The RGCs treated with high glucose levels exhibited significantly increased apoptotic rate and concentrations of ROS and MDA. Pretreatment of the cells with EPO caused a significant blockade of the high glucose-induced increase in ROS and MDA levels and apoptotic rate. EPO also increased the activities of SOD, GSH-Px, and CAT, and recovered the levels of T-AOC levels. As a consequence, the mitochondrial membrane potential was improved and Cyt c release into the cytoplasm was prevented which led to significantly suppressed up-regulation of Bax reducing the Bax/Bcl-2 ratio. The expressions of caspase-3 and caspase-9 induced by high glucose exposure were also ameliorated in the RGCs treated with EPO. The protective effect of EPO against apoptosis was mediated through its antioxidant action. Thus, it blocked the generation of pro-apoptotic proteins and apoptotic degeneration of the RGCs by preventing the mitochondrial damage.

  2. Transcorneal electrical stimulation alters morphology and survival of retinal ganglion cells after optic nerve damage.

    PubMed

    Henrich-Noack, Petra; Voigt, Nadine; Prilloff, Sylvia; Fedorov, Anton; Sabel, Bernhard A

    2013-05-24

    Traumatic optic nerve injury leads to retrograde death of retinal ganglion cells (RGCs), but transcorneal electrical stimulation (TES) can increase the cell survival rate. To understand the mechanisms and to further define the TES-induced effects we monitored in living animals RGC morphology and survival after optic nerve crush (ONC) in real time by using in vivo confocal neuroimaging (ICON) of the retina. ONC was performed in rats and ICON was performed before crush and on post-lesion days 3, 7 and 15 which allowed us to repeatedly record RGC number and size. TES or sham-stimulation were performed immediately after the crush and on post-injury day 11. Three days after ONC we detected a higher percentage of surviving RGCs in the TES group as compared to sham-treated controls. However, the difference was below significance level on day 7 and disappeared completely by day 15. The death rate was more variable amongst the TES-treated rats than in the control group. Morphological analysis revealed that average cell size changed significantly in the control group but not in stimulated animals and the morphological alterations of surviving neurons were smaller in TES-treated compared to control cells. In conclusion, TES delays post-traumatic cell death significantly. Moreover, we found "responder animals" which also benefited in the long-term from the treatment. Our in vivo cellular imaging results provide evidence that TES reduces ONC-associated neuronal swelling and shrinkage especially in RGCs which survived long-term. Further studies are now needed to determine the differences of responders vs. non-responders.

  3. Retinal ganglion cell neuroprotection in a rat model of glaucoma following brimonidine, latanoprost or combined treatments.

    PubMed

    Hernández, María; Urcola, J Haritz; Vecino, Elena

    2008-05-01

    The aim of the present study is to evaluate the neuroprotective effect of two antiglaucomatous substances, regardless of their hypotensive effect in the eye. Brimonidine, which does not reduce IOP when administered intraperitoneally, and latanoprost, which has a renowned hypotensive effect topically. We examined rat retinal ganglion cell (RGC) survival and size distribution in experimental glaucoma in response to different glaucomatous agents. IOP was elevated by episcleral vein cauterization (EVC) prior to the application of different treatments: (I) PBS application (control group), (II) intraperitoneal administration of brimonidine (a general hypotensive agent), (III) topical application of latanoprost (an ocular hypotensive agent), and (IV) latanoprost combined with brimonidine. After 12 weeks, RGCs were retrogradely labeled with fluorogold and RGC density was analyzed. EVC caused a significant increase (42%) in IOP in each group before drug treatment. After 12weeks of EVC, RGC survival in control vs. EVC rats was 78.9+/-3.2%. No IOP reduction was observed in brimonidine injected rats, but RGC survival at 12 weeks was total (103.7+/-2.7%). In latanoprost treated rats, IOP dropped by around 22% and 94.7+/-3.7% of the RGC population survived. Finally in the latanoprost+brimonidine combined group, IOP was significantly reduced by 25% and 94.4+/-2.2% of RGCs survived. Surprisingly, whereas EVC led to a 6% increase in RGC soma size, brimonidine treatment was associated with a 9% reduction in the soma size of RGCs at 12 weeks. We conclude that brimonidine exerts a neuroprotective effect via a mechanism which is independent of IOP reduction. These findings indicate that cell survival in glaucoma may be enhanced by neuroprotective strategies which are independent of IOP reduction. No synergistic neuroprotective effect was observed when both treatments were applied simultaneously.

  4. A five-primary photostimulator suitable for studying intrinsically photosensitive retinal ganglion cell functions in humans

    PubMed Central

    Cao, Dingcai; Nicandro, Nathaniel; Barrionuevo, Pablo A.

    2015-01-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) can respond to light directly through self-contained photopigment, melanopsin. IpRGCs also receive synaptic inputs from rods and cones. Thus, studying ipRGC functions requires a novel photostimulating method that can account for all of the photoreceptor inputs. Here, we introduced an inexpensive LED-based five-primary photostimulator that can control the excitations of rods, S-, M-, L-cones, and melanopsin-containing ipRGCs in humans at constant background photoreceptor excitation levels, a critical requirement for studying the adaptation behavior of ipRGCs with rod, cone, or melanopsin input. We described the theory and technical aspects (including optics, electronics, software, and calibration) of the five-primary photostimulator. Then we presented two preliminary studies using the photostimulator we have implemented to measure melanopsin-mediated pupil responses and temporal contrast sensitivity function (TCSF). The results showed that the S-cone input to pupil responses was antagonistic to the L-, M- or melanopsin inputs, consistent with an S-OFF and (L + M)-ON response property of primate ipRGCs (Dacey et al., 2005). In addition, the melanopsin-mediated TCSF had a distinctive pattern compared with L + M or S-cone mediated TCSF. Other than controlling individual photoreceptor excitation independently, the five-primary photostimulator has the flexibility in presenting stimuli modulating any combination of photoreceptor excitations, which allows researchers to study the mechanisms by which ipRGCs combine various photoreceptor inputs. PMID:25624466

  5. Hypoxia-induced retinal ganglion cell death and the neuroprotective effects of beta-adrenergic antagonists.

    PubMed

    Chen, Yi-Ning; Yamada, Hideyuki; Mao, Wei; Matsuyama, Shigemi; Aihara, Makoto; Araie, Makoto

    2007-05-07

    Hypoxia-induced retinal ganglion cell (RGC) death has been implicated in glaucomatous optic neuropathy. However, the precise mechanism of death signaling and how neuroprotective agents affect it are still unclear. The aim of this study is to characterize the mechanisms of hypoxia-induced apoptosis of cultured purified RGCs and to study the neuroprotective effects of beta-adrenergic antagonists. Rat RGCs were purified utilizing a modified two-step immuno-panning procedure. First, the extent of apoptosis in RGCs under hypoxia was quantified. Next, the effects of glutamate-channel antagonists (MK801 or DNQX), Bax inhibiting peptide (BIP), and beta-adrenergic antagonists (betaxolol, nipradilol, timolol or carteolol) on hypoxia-induced RGC death were investigated by the cell viability assay. Third, the effects of beta-adrenergic antagonists on hypoxia-induced increase of intracellular calcium concentrations ([Ca(2+)](i)) and the additional effect of NO scavenger to nipradilol were evaluated. Apoptotic RGC percentages under hypoxia were significantly increased compared to the control. The viability of RGCs under hypoxia was not affected by MK801 or DNQX, whereas it was increased in a dose-dependent manner with exposure to BIP, and to betaxolol, nipradilol, timolol, but not to carteolol. These effective beta-adrenergic antagonists showed no significant change in hypoxia-induced [Ca(2+)](i) levels. The NO scavenger alleviated neuroprotective effect by nipradilol. In conclusion, purified RGC damage induced by hypoxia involves Bax-dependent apoptotic pathway, but mostly independent of glutamate receptor-mediated excitotoxicity. Betaxolol, timolol and nipradilol showed a protective effect against hypoxia-induced RGC death, which was thought to be irrelevant either to calcium channel or beta-adrenoceptor blocking effects.

  6. The neuroprotective effect of resveratrol on retinal ganglion cells after optic nerve transection

    PubMed Central

    Park, Joo Hyun; Kim, Yu Jeong; Park, Ki Ho

    2013-01-01

    Purpose This study aimed to investigate the neuroprotective effect of resveratrol in an optic nerve transection (ONT) model and to identify the neuroprotective mechanism of resveratrol in retinal ganglion cells (RGCs). Methods ONT and retrograde labeling were performed in Sprague-Dawley rats. Various concentrations of resveratrol were injected intravitreally immediately after ONT. The number of labeled RGCs was determined at 1 and 2 weeks after ONT. The effect of resveratrol and sirtinol (a sirtuin 1 inhibitor) co-injection was investigated. RGC-5 cells were cultured and treated with staurosporine to induce differentiation. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate the effect of resveratrol on RGC-5 cell survival under serum-free conditions. RGC-5 cells were cultured with sirtinol to investigate the neuroprotective mechanism of resveratrol. Results A dose–response relationship was observed between resveratrol and RGC survival. A single intravitreal injection of resveratrol was neuroprotective in RGCs at 1 week after ONT (p<0.01). Repeated intravitreal injection of resveratrol showed a neuroprotective effect at 2 weeks after ONT (p<0.01). However, co-injection of resveratrol and sirtinol diminished the neuroprotective effect of resveratrol (p<0.05). The neuroprotective effect of resveratrol was observed in RGC-5 cells under serum-free conditions, and sirtinol diminished this neuroprotective effect. Conclusions Resveratrol exerts its neuroprotective effect on RGCs via activation of the sirtuin 1 pathway in an ONT model. This finding demonstrates the therapeutic potential of resveratrol in treating optic nerve diseases. PMID:23901250

  7. Early Gene Expression Changes in the Retinal Ganglion Cell Layer of a Rat Glaucoma Model

    PubMed Central

    Guo, Ying; Johnson, Elaine C.; Cepurna, William O.; Dyck, Jennifer A.; Doser, Tom

    2011-01-01

    Purpose. To identify patterns of early gene expression changes in the retinal ganglion cell layer (GCL) of a rodent model of chronic glaucoma. Methods. Prolonged elevation of intraocular pressure (IOP) was produced in rats by episcleral vein injection of hypertonic saline (N = 30). GCLs isolated by laser capture microdissection were grouped by grading of the nerve injury (<25% axon degeneration for early injury; >25% for advanced injury). Gene expression was determined by cDNA microarray of independent GCL RNA samples. Quantitative PCR (qPCR) was used to further examine the expression of selected genes. Results. By array analysis, 533 GCL genes (225 up, 308 down) were significantly regulated in early injury. Compared to only one major upregulated gene class of metabolism regulation, more were downregulated, including mitochondria, ribosome, proteasome, energy pathways, protein synthesis, protein folding, and synaptic transmission. qPCR confirmed an early upregulation of Atf3. With advanced injury, 1790 GCL genes were significantly regulated (997 up, 793 down). Altered gene categories included upregulated protein synthesis, immune response, and cell apoptosis and downregulated dendrite morphogenesis and axon extension. Of all the early changed genes, 50% were not present in advanced injury. These uniquely affected genes were mainly associated with upregulated transcription regulation and downregulated protein synthesis. Conclusions. Early GCL gene responses to pressure-induced injury are characterized by an upregulation of Atf3 and extensive downregulation in genes associated with cellular metabolism and neuronal functions. Most likely, these changes represent those specific to RGCs and are thus potentially important for enhancing RGC survival in glaucoma. PMID:21051717

  8. A five-primary photostimulator suitable for studying intrinsically photosensitive retinal ganglion cell functions in humans.

    PubMed

    Cao, Dingcai; Nicandro, Nathaniel; Barrionuevo, Pablo A

    2015-01-26

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) can respond to light directly through self-contained photopigment, melanopsin. IpRGCs also receive synaptic inputs from rods and cones. Thus, studying ipRGC functions requires a novel photostimulating method that can account for all of the photoreceptor inputs. Here, we introduced an inexpensive LED-based five-primary photostimulator that can control the excitations of rods, S-, M-, L-cones, and melanopsin-containing ipRGCs in humans at constant background photoreceptor excitation levels, a critical requirement for studying the adaptation behavior of ipRGCs with rod, cone, or melanopsin input. We described the theory and technical aspects (including optics, electronics, software, and calibration) of the five-primary photostimulator. Then we presented two preliminary studies using the photostimulator we have implemented to measure melanopsin-mediated pupil responses and temporal contrast sensitivity function (TCSF). The results showed that the S-cone input to pupil responses was antagonistic to the L-, M- or melanopsin inputs, consistent with an S-OFF and (L + M)-ON response property of primate ipRGCs (Dacey et al., 2005). In addition, the melanopsin-mediated TCSF had a distinctive pattern compared with L + M or S-cone mediated TCSF. Other than controlling individual photoreceptor excitation independently, the five-primary photostimulator has the flexibility in presenting stimuli modulating any combination of photoreceptor excitations, which allows researchers to study the mechanisms by which ipRGCs combine various photoreceptor inputs. © 2015 ARVO.

  9. Photoresponse diversity among the five types of intrinsically photosensitive retinal ganglion cells.

    PubMed

    Zhao, Xiwu; Stafford, Ben K; Godin, Ashley L; King, W Michael; Wong, Kwoon Y

    2014-04-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) mediate non-image-forming visual responses, including pupillary constriction, circadian photoentrainment and suppression of pineal melatonin secretion. Five morphological types of ipRGCs, M1-M5, have been identified in mice. In order to understand their functions better, we studied the photoresponses of all five cell types, by whole-cell recording from fluorescently labelled ipRGCs visualized using multiphoton microscopy. All ipRGC types generated melanopsin-based ('intrinsic') as well as synaptically driven ('extrinsic') light responses. The intrinsic photoresponses of M1 cells were lower threshold, higher amplitude and faster than those of M2-M5. The peak amplitudes of extrinsic light responses differed among the ipRGC types; however, the responses of all cell types had comparable thresholds, kinetics and waveforms, and all cells received rod input. While all five types exhibited inhibitory amacrine-cell and excitatory bipolar-cell inputs from the 'on' channel, M1 and M3 received additional 'off'-channel inhibition, possibly through their 'off'-sublamina dendrites. The M2-M5 ipRGCs had centre-surround-organized receptive fields, implicating a capacity to detect spatial contrast. In contrast, the receptive fields of M1 cells lacked surround antagonism, which might be caused by the surround of the inhibitory input nullifying the surround of the excitatory input. All ipRGCs responded robustly to a wide range of motion speeds, and M1-M4 cells appeared tuned to different speeds, suggesting that they might analyse the speed of motion. Retrograde labelling revealed that M1-M4 cells project to the superior colliculus, suggesting that the contrast and motion information signalled by these cells could be used by this sensorimotor area to detect novel objects and motion in the visual field.

  10. Nerve fiber layer thinning lags retinal ganglion cell density following crush axonopathy.

    PubMed

    Munguba, Gustavo C; Galeb, Sanja; Liu, Yuan; Landy, David C; Lam, Daisy; Camp, Andrew; Samad, Sinthia; Tapia, Mary L; Lee, Richard K

    2014-09-16

    We investigated the progressive nature of neurodegenerative structural changes following injury to retinal ganglion cell (RGC) axons using quantifiable and noninvasive in vivo imaging techniques. To track degenerative RGC progression in retinas following optic nerve crush (ONC) injury, spectral-domain optical coherence tomography (SD-OCT) was used to quantitate the RGC nerve fiber layer (NFL) density. The RGC soma cell density (RCD) was measured by confocal scanning laser ophthalmoscopy (CSLO). The RCD counts were performed using blood vessels as landmarks to anatomically track defined progressive changes in enhanced yellow fluorescent fusion protein (EYFP)-labeled RGCs. Following ONC injury, 68% of the observed decrease in RCD measured by CSLO and 54% of the NFL thickness obtained by SD-OCT imaging (N=4 retinas) occurred within the first week. Between days 7 and 14, an additional 22% decrease in RCD was concurrent with a 31% decrease in overall NFL thickness. Finally, between days 14 and 21, an additional 10% decrease in RCD measured in vivo by CSLO and 15% decrease in NFL thickness by SD-OCT was observed. Our data suggest that in vivo CSLO imaging of EYFP-RGC expression and SD-OCT measured NFL thickness are fast and reliable methods that longitudinally track neurodegenerative progression following ONC injury. Neurodegenerative changes in NFL thickness measured by SD-OCT imaging have the same overall trajectory as those observed by CSLO for RCD; however, changes in NFL thickness initially lag behind in vivo RGC soma counts with a slower decline in overall measurable change. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  11. Critical role of calpain in axonal damage-induced retinal ganglion cell death.

    PubMed

    Ryu, Morin; Yasuda, Masayuki; Shi, Dong; Shanab, Ahmed Y; Watanabe, Ryo; Himori, Noriko; Omodaka, Kazuko; Yokoyama, Yu; Takano, Jiro; Saido, Takaomi; Nakazawa, Toru

    2012-04-01

    Calpain, an intracellular cysteine protease, has been widely reported to be involved in neuronal cell death. The purpose of this study is to investigate the role of calpain activation in axonal damage-induced retinal ganglion cell (RGC) death. Twelve-week-old male calpstatin (an endogenous calpain inhibitor) knockout mice (CAST KO) and wild-type (WT) mice were used in this study. Axonal damage was induced by optic nerve crush (NC) or tubulin destruction induced by leaving a gelatin sponge soaked with vinblastine (VB), a microtubule disassembly chemical, around the optic nerve. Calpain activation was assessed by immunoblot analysis, which indirectly quantified the cleaved α-fodrin, a substrate of calpain. RGCs were retrogradely labeled by injecting a fluorescent tracer, Fluoro-Gold (FG), and the retinas were harvested and flat-mounted retinas prepared. The densities of FG-labeled RGCs harvested from the WT and CAST KO groups were assessed and compared. Additionally, a calpain inhibitor (SNJ-1945, 100 mg/kg/day) was administered orally, and the density of surviving RGCs was compared with that of the vehicle control group. The mean density of surviving RGCs in the CAST KO group was significantly lower than that observed in the WT group, both in NC and in VB. The mean density of surviving RGCs in the SNJ-1945-treated group was significantly higher than that of the control group. The calpain inhibitor SNJ-1945 has a neuroprotective effect against axonal damage-induced RGC death. This pathway may be an important therapeutic target for preventing this axonal damage-induced RGC death, including glaucoma and diabetic optic neuropathy and other CNS diseases that share a common etiology. Copyright © 2011 Wiley Periodicals, Inc.

  12. Retinal ganglion cell complex changes using spectral domain optical coherence tomography in diabetic patients without retinopathy

    PubMed Central

    Hegazy, Ahmed I.; Zedan, Rasha H.; Macky, Tamer A.; Esmat, Soheir M.

    2017-01-01

    AIM To assess the ganglion cell complex (GCC) thickness in diabetic eyes without retinopathy. METHODS Two groups included 45 diabetic eyes without retinopathy and 21 non diabetic eyes. All subjects underwent full medical and ophthalmological history, full ophthalmological examination, measuring GCC thickness and central foveal thickness (CFT) using the RTVue® spectral domain-optical coherence tomography (SD-OCT), and HbA1C level. RESULTS GCC focal loss volume (FLV%) was significantly more in diabetic eyes (22.2% below normal) than normal eyes (P=0.024). No statistically significant difference was found between the diabetic group and the control group regarding GCC global loss volume (GLV%) (P=0.160). CFT was positively correlated to the average, superior and inferior GCC (P=0.001, 0.000 and 0.001 respectively) and negatively correlated to GLV% and FLV% (P=0.002 and 0.031 respectively) in diabetic eyes. C/D ratio in diabetic eyes was negatively correlated to average, superior and inferior GCC (P=0.015, 0.007 and 0.017 respectively). The FLV% was negatively correlated to the refraction and level of HbA1c (P=0.019 and 0.013 respectively) and positively correlated to the best corrected visual acuity (BCVA) in logMAR in diabetic group (P=0.004). CONCLUSION Significant GCC thinning in diabetes predates retinal vasculopathy, which is mainly focal rather than diffuse. It has no preference to either the superior or inferior halves of the macula. Increase of myopic error is significantly accompanied with increased focal GCC loss. GCC loss is accompanied with increased C/D ratio in diabetic eyes. PMID:28393035

  13. Molecular mechanisms underlying activity-dependent AMPA receptor cycling in retinal ganglion cells

    PubMed Central

    Casimiro, Tanya M.; Nawy, Scott; Carroll, Reed C.

    2013-01-01

    On retinal ganglion cells (RGCs) transmit light encoded information to the brain and receive excitatory input from On cone bipolar cells (CBPs). The synaptic CBP input onto On RGCs is mediated by AMPA-type glutamate receptors (AMPARs) that include both those lacking a GluA2 subunit, and are therefore permeable to Ca2+, and those that possess at least one GluA2 subunit and are Ca2+-impermeable. We have previously demonstrated in electrophysiological studies that periods of low synaptic activity, brought about by housing animals in darkness, enhances the proportion of GluA2-lacking AMPARs at the On CBP-On RGC synapse by mobilizing surface GluA2 containing receptors into a receptor pool that rapidly cycles in and out of the membrane. AMPAR cycling induction by reduced synaptic activity takes several hours. This delay suggests that changes in expression of proteins which regulate AMPAR trafficking may mediate the altered mobility of GluA2 AMPARs in RGCs. In this study, we test the hypothesis that AMPAR trafficking proteins couple synaptic activity to AMPAR cycling in RGCs. Immunocytochemical and biochemical analysis confirmed that darkness decreases surface GluA2 in RGCs and changed the expression levels of three proteins associated with GluA2 trafficking. GRIP was decreased, while PICK1 and Arc were increased. Knockdown of GRIP with siRNA elevated constitutive AMPAR cycling, mimicking effects of reduced synaptic activity, while knockdown of PICK1 and ARC blocked increases in constitutive GluA2 trafficking. Our results support a role for correlated, activity-driven changes in multiple AMPAR trafficking proteins that modulate GluA2 cycling which can in turn affect synaptic AMPAR composition in RGCs. PMID:23911793

  14. Nerve Fiber Layer Thinning Lags Retinal Ganglion Cell Density Following Crush Axonopathy

    PubMed Central

    Munguba, Gustavo C.; Galeb, Sanja; Liu, Yuan; Landy, David C.; Lam, Daisy; Camp, Andrew; Samad, Sinthia; Tapia, Mary L.; Lee, Richard K.

    2014-01-01

    Purpose. We investigated the progressive nature of neurodegenerative structural changes following injury to retinal ganglion cell (RGC) axons using quantifiable and noninvasive in vivo imaging techniques. Methods. To track degenerative RGC progression in retinas following optic nerve crush (ONC) injury, spectral-domain optical coherence tomography (SD-OCT) was used to quantitate the RGC nerve fiber layer (NFL) density. The RGC soma cell density (RCD) was measured by confocal scanning laser ophthalmoscopy (CSLO). The RCD counts were performed using blood vessels as landmarks to anatomically track defined progressive changes in enhanced yellow fluorescent fusion protein (EYFP)-labeled RGCs. Results. Following ONC injury, 68% of the observed decrease in RCD measured by CSLO and 54% of the NFL thickness obtained by SD-OCT imaging (N = 4 retinas) occurred within the first week. Between days 7 and 14, an additional 22% decrease in RCD was concurrent with a 31% decrease in overall NFL thickness. Finally, between days 14 and 21, an additional 10% decrease in RCD measured in vivo by CSLO and 15% decrease in NFL thickness by SD-OCT was observed. Conclusions. Our data suggest that in vivo CSLO imaging of EYFP-RGC expression and SD-OCT measured NFL thickness are fast and reliable methods that longitudinally track neurodegenerative progression following ONC injury. Neurodegenerative changes in NFL thickness measured by SD-OCT imaging have the same overall trajectory as those observed by CSLO for RCD; however, changes in NFL thickness initially lag behind in vivo RGC soma counts with a slower decline in overall measurable change. PMID:25228542

  15. Inhibition of TLR4 alleviates the inflammation and apoptosis of retinal ganglion cells in high glucose.

    PubMed

    Hu, Lili; Yang, Hongxia; Ai, Ming; Jiang, Shuanghong

    2017-08-14

    To investigate the expression profiles of Toll-like receptor 4 (TLR4), the effect of TLR4 on inflammation, and apoptosis of retinal ganglion cells (RGCs) cultured in high glucose and the underlying mechanism. A high-glucose model was established in RGCs isolated from Sprague-Dawley (SD) rats (2-3 days old) and identified with Brn3a. Primary cultured RGCs were divided into control (0 mM), HG1 (10 mM glucose), HG2 (20 mM glucose), HG3 (30 mM glucose), HG (20 mM glucose) + TAK-242 (1.0 μM), and HG (20 mM glucose) + vehicle (1% DMSO) groups. The expression levels of TLR4, its downstream signalling molecules, and pro-inflammatory cytokines were measured by real-time PCR, Western blot or ELISA at 24 h and 48 h. The apoptosis rate of RGCs was measured by flow cytometry. The mRNA and protein expression levels of TLR4 were increased in high-glucose groups (10 mM, 20 mM, 30 mM). Consistent with these findings, four TLR4 downstream signalling molecules (MyD88, NF-κB, TRAF6, NLRP3) and pro-inflammatory cytokines (IL-1β, IL-18) were upregulated in the three high-glucose groups. Apoptosis of RGCs was clearly increased in the high-glucose group. The administration of TAK-242, an antagonist of TLR4, inhibited inflammation and apoptosis of RGCs in the high-glucose group. Our results demonstrated that TLR4 plays a critical role in the inflammation and apoptosis of RGCs induced by high glucose. TLR4 might become a novel potential pharmacological target for preventing the progression of DR.

  16. Posttranslational modification of neurofilament proteins by phosphate during axoplasmic transport in retinal ganglion cell neurons.

    PubMed

    Nixon, R A; Lewis, S E; Marotta, C A

    1987-04-01

    The progressive modification of newly synthesized neurofilament proteins (NFPs) during axoplasmic transport in mouse retinal ganglion cell (RGC) neurons was studied after RGC perikarya were pulse-labeled with 32P-orthophosphate or radiolabeled amino acids. The 3 NFP subunits, H(igh), M(iddle), and L(ow), were among a group of axonally transported proteins that incorporated high levels of 32P. Covalent addition of phosphate slowed the electrophoretic mobility of H and M on SDS polyacrylamide gels and shifted the charge of all 3 subunits toward more acidic pH values, thereby providing an index of the phosphorylation state of this radiolabeled population of NFPs. NFPs were extensively phosphorylated before they entered axons at the optic nerve level, and continued to be modified during transport along RGC axons at the optic nerve and tract level. H and M exhibited charge shifts of 0.2-0.6 units toward a more acidic pH during axoplasmic transport. The charge modifications became more prominent when NFPs reached distal axonal levels, which may indicate regional differences in the activity of this modification process along axons. By contrast, the L subunit became more basic in charge, consistent with decreases in the phosphorylation state during transport. Additional observations (Nixon and Lewis, 1986) that a considerable proportion of phosphate groups initially added to L and M were later removed as neurofilaments advanced along RGC axons support the notion that the changing phosphorylation state of NFP subunits during axoplasmic transport reflects a dynamic equilibrium between phosphorylation and dephosphorylation events. Topographical remodeling of phosphate groups on NFPs during axoplasmic transport is proposed as a possible mechanism for coordinating interactions between neurofilaments and other constituents, as these elements are transported and integrated into the axonal cytoskeleton.

  17. Retinal ganglion cell protection with geranylgeranylacetone, a heat shock protein inducer, in a rat glaucoma model.

    PubMed Central

    Caprioli, Joseph; Ishii, Yoko; Kwong, Jacky M K

    2003-01-01

    PURPOSE: To study the effects of geranylgeranylacetone (GCA) on the expression of inducible (HSP72) and constitutive (HSC70) heat shock proteins (HSPs) on retinal ganglion cells (RGCs) in a rat model of glaucoma. METHODS: Adult Wistar rats were given intraperitoneal injections of GGA, 200 mg/kg daily. Western blot analysis and immunohistochemical staining for HSP72 and HSC70 were performed after 1, 3, and 7 days of GGA administration. After 7 days of GGA pretreatment, intraocular pressure (IOP) was elevated unilaterally by repeated trabecular argon laser photocoagulation 5 days after intracameral injection of india ink. After the first laser photocoagulation, CGA was given twice a week. RGC survival was evaluated after 5 weeks of IOP elevation. Immunohistochemistry and TdT-mediated biotin-dUTP nick end labeling (TUNEL) were performed after 1 week of IOP elevation. Quercetin, an inhibitor of HSP expression, was also administered to a separate group. RESULTS: There was increased expression of HSP72 in RGCs at 3 and 7 days after GGA administration, but HSC70 was unchanged. After 5 weeks of IOP elevation, there was 27% +/- 6% loss of RGCs. The administration of GGA significantly reduced the loss of RGCs, lessened optic nerve damage, decreased the number of TUNEL-positive cells in the RGC layer, and increased HSP72. Quercetin administration abolished these protective effects. CONCLUSIONS: These results demonstrate that systemic administration of GGA protects RGCs from glaucomatous damage in a rat model and suggest a novel pathway for netroprotection for patients with glaucoma. PMID:14971562

  18. Effect of Müller cells on the survival and neuritogenesis in retinal ganglion cells.

    PubMed

    Ruzafa, N; Vecino, E

    2015-11-01

    Retinal ganglion cells (RGCs) are the first affected cells in neuropathies like glaucoma, for that reason it is very important to explore new methods to neuroprotect these neurons. Müller cells are glial cells that provide the neurons with trophic factors and scaffold. The purpose of this study was to analyze the effect of Müller cells on survival and neurite formation in RGCs. Rat Müller cells were grown until a confluent culture on which rat RGCs were added, using pure culture of rat RGCs as controls. RGCs were labeled with βIII-tubulin, and Müller cells with glutamine synthetase antibodies. In addition, nuclei were stained with DAPI. The number of RGCs and number and neurite length were measured. No differences were found in the number of RGCs between control and cells grown on the substrate of Müller cells. The proportion of RGCs with neurites increased when they grew on Müller (RGCs with 1-3 neurites increased from 19% to 43%. The length of neurites also increased in RGCs grown on Müller cells, with the number of RGCs with neurites from 50 to 200μm increasing from 21% to 41%, and with neurites of more than 200μm the increase was from 6% to 20%. Müller cells support the survival of RGCs and induced an increase in the number and length of neurites of RGCs. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  19. Retinal ganglion cell responses to voltage and current stimulation in wild-type and rd1 mouse retinas

    NASA Astrophysics Data System (ADS)

    Goo, Yong Sook; Ye, Jang Hee; Lee, Seokyoung; Nam, Yoonkey; Ryu, Sang Baek; Kim, Kyung Hwan

    2011-06-01

    Retinal prostheses are being developed to restore vision for those with retinal diseases such as retinitis pigmentosa or age-related macular degeneration. Since neural prostheses depend upon electrical stimulation to control neural activity, optimal stimulation parameters for successful encoding of visual information are one of the most important requirements to enable visual perception. In this paper, we focused on retinal ganglion cell (RGC) responses to different stimulation parameters and compared threshold charge densities in wild-type and rd1 mice. For this purpose, we used in vitro retinal preparations of wild-type and rd1 mice. When the neural network was stimulated with voltage- and current-controlled pulses, RGCs from both wild-type and rd1 mice responded; however the temporal pattern of RGC response is very different. In wild-type RGCs, a single peak within 100 ms appears, while multiple peaks (approximately four peaks) with ~10 Hz rhythm within 400 ms appear in RGCs in the degenerated retina of rd1 mice. We find that an anodic phase-first biphasic voltage-controlled pulse is more efficient for stimulation than a biphasic current-controlled pulse based on lower threshold charge density. The threshold charge densities for activation of RGCs both with voltage- and current-controlled pulses are overall more elevated for the rd1 mouse than the wild-type mouse. Here, we propose the stimulus range for wild-type and rd1 retinas when the optimal modulation of a RGC response is possible.

  20. The neuroprotective effect of carnosine (β-alanyl-L-histidine) on retinal ganglion cell following ischemia-reperfusion injury.

    PubMed

    Ji, Yong-Sok; Park, Jung-Won; Heo, Hwan; Park, Jong-Seong; Park, Sang-Woo

    2014-06-01

    To investigate whether carnosine can increase retinal ganglion cell (RGC) survival in ischemic mouse retina. Retinal ischemia was induced by constant elevation of intraocular pressure (100-110 mmHg) for 60 min in C57BL/6 J mice pretreated with carnosine (1000 mg/kg) or saline. Hypoxia inducing factor-1 alpha (HIF-1α), glial fibrillary acidic protein (GFAP), and dynamin-related protein-1 (Drp-1) expressions were assessed at 6, 12, and 24 h after retinal ischemia. Bax and Bcl-2 expressions were also analyzed at 12 h after retinal ischemia. RGC survival was assessed by retrograde FluoroGold labeling at 2 weeks after retinal ischemia. The expression of HIF-1α, GFAP, and Drp-1 was increased within 24 h after ischemic injury. Carnosine treatment effectively decreased the elevated expression of HIF-1α, GFAP, and Drp-1 in ischemic mouse retina. In ischemic retina treated with carnosine, Bax expression was decreased, whereas Bcl-2 expression was increased compared with ischemic retina treated with saline. Carnosine treatment also protected against RGC loss in ischemia mouse retina. Our findings showed that carnosine treatment significantly decreased RGC loss through decreased expression of HIF-1α, GFAP, Drp-1, and Bax, and increased expression of Bcl-2 in ischemic mouse retina. We suggest that carnosine can be an effective endogenous neuroprotective molecule in the prevention of RGC loss in ischemic retina.

  1. A high frequency resonance in the responses of retinal ganglion cells to rapidly modulated stimuli: A computer model

    PubMed Central

    MILLER, J.A.; DENNING, K.S.; GEORGE, J.S.; MARSHAK, D.W.; KENYON, G.T.

    2012-01-01

    Brisk Y-type ganglion cells in the cat retina exhibit a high frequency resonance (HFR) in their responses to large, rapidly modulated stimuli. We used a computer model to test whether negative feedback mediated by axon-bearing amacrine cells onto ganglion cells could account for the experimentally observed properties of HFRs. Temporal modulation transfer functions (tMTFs) recorded from model ganglion cells exhibited HFR peaks whose amplitude, width, and locations were qualitatively consistent with experimental data. Moreover, the wide spatial distribution of axon-mediated feedback accounted for the observed increase in HFR amplitude with stimulus size. Model phase plots were qualitatively similar to those recorded from Y ganglion cells, including an anomalous phase advance that in our model coincided with the amplification of low-order harmonics that overlapped the HFR peak. When axon-mediated feedback in the model was directed primarily to bipolar cells, whose synaptic output was graded, or else when the model was replaced with a simple cascade of linear filters, it was possible to produce large HFR peaks but the region of anomalous phase advance was always eliminated, suggesting the critical involvement of strongly non-linear feedback loops. To investigate whether HFRs might contribute to visual processing, we simulated high frequency ocular tremor by rapidly modulating a naturalistic image. Visual signals riding on top of the imposed jitter conveyed an enhanced representation of large objects. We conclude that by amplifying responses to ocular tremor, HFRs may selectively enhance the processing of large image features. PMID:17020633

  2. Live or let die - retinal ganglion cell death and survival during development and in the lesioned adult CNS.

    PubMed

    Bähr, M

    2000-10-01

    Programmed cell death or apoptosis is a common and widespread phenomenon that is important for proper development of the nervous system. In the adult CNS, however, apoptosis contributes to secondary cell loss after various types of lesions. The retino-tectal system has been successfully used as a convenient model system to study the molecular mechanisms of neuronal apoptosis and survival during development and in the lesioned adult CNS. This review describes the current knowledge about the interactions of cell death and survival pathways in general and for retinal ganglion cells specifically.

  3. Retinal ganglion cell topography and spatial resolving power in the oriental fire-bellied toad Bombina orientalis.

    PubMed

    Pushchin, Igor I; Zyumchenko, Nataliya E

    2015-12-01

    The vertebrate visual system is determined by two main factors, a species' lifestyle and phylogenetic legacy. Studying the visual system in outgroup lineages may shed some light on the balance of these factors within a certain radiation. We studied the topography of retinal ganglion cells (RGCs) in the retina of the oriental fire-bellied toad Bombina orientalis. These toads belong to the ancient superfamily Discoglossoidea, a sister group to all extant Anura except for two small families. RGCs were retrogradely labeled with tetramethylrhodamine- dextran amine (TMR-DA) and examined in retinal wholemounts. RGCs occurred all over the retina except for the far periphery. Their total number was [Formula: see text] ([Formula: see text], [Formula: see text]). They comprised 73-77% of all cells in the ganglion cell layer. The spatial density of GCs increased gradually from the dorsal and ventral retinal periphery toward the equator to form a weak visual streak and a moderately pronounced area centralis. The minimum density was [Formula: see text], and the maximum, [Formula: see text]. The maximum density gradient was [Formula: see text]. The spatial resolution was minimum in the dorsal and ventral periphery ([Formula: see text] and [Formula: see text] cycles per degree in water and air, respectively). Intermediate values of spatial resolving power were found within the visual streak ([Formula: see text] and [Formula: see text] cycles per degree) and reached a peak in area centralis ([Formula: see text] and [Formula: see text] cycles per degree). This is sufficient for efficient prey location and capture. The relatively high RGC density and the presence of specialized retinal regions in oriental fire-bellied toads are consistent with their highly visual behavior. A brief review comparing the phylogeny and ecology of this with other anuran species suggests that the main factor shaping the RGC distribution in Anura is phylogenetic legacy; the environmental pressure results

  4. Mechanisms by which cell geometry controls repetitive impulse firing in retinal ganglion cells.

    PubMed

    Fohlmeister, J F; Miller, R F

    1997-10-01

    impulse initiation varies greatly and depends on the stimulus magnitude. Models that conform to physiological constraints also show irregular firing, particularly for near threshold stimulation of the soma, due to multiple sites of impulse initiation. Such behavior could represent an asset to the cells for conveying information under conditions of low contrast stimulation. Multiple spike initiation zones also can provide retinal ganglion cells with a variety of response characteristics, including spike doublets, depending on the level of cell activation. Increasing the diameter of the dendritic equivalent cylinder reduces the impulse frequency (F/I) response. Over a restricted range of ion channel densities in the dendritic tree, phase locking between dendritic membrane oscillations and somatic spiking can occur with dendritic stimulation, and mathematical chaos can be demonstrated when sufficiently thin dendritic processes are present. We conclude that cell morphology is the primary factor in determining firing patterns and the impulse frequency response of a given cell and that differences in channel density distribution across a population of cells plays, at most, a secondary role in this function. This conclusion applies to both synaptic activation and electrode stimulation of the soma.

  5. Nel positively regulates the genesis of retinal ganglion cells by promoting their differentiation and survival during development.

    PubMed

    Nakamoto, Chizu; Kuan, Soh-Leh; Findlay, Amy S; Durward, Elaine; Ouyang, Zhufeng; Zakrzewska, Ewa D; Endo, Takuma; Nakamoto, Masaru

    2014-01-01

    For correct functioning of the nervous system, the appropriate number and complement of neuronal cell types must be produced during development. However, the molecular mechanisms that regulate the production of individual classes of neurons are poorly understood. In this study, we investigate the function of the thrombospondin-1-like glycoprotein, Nel (neural epidermal growth factor [EGF]-like), in the generation of retinal ganglion cells (RGCs) in chicks. During eye development, Nel is strongly expressed in the presumptive retinal pigment epithelium and RGCs. Nel overexpression in the developing retina by in ovo electroporation increases the number of RGCs, whereas the number of displaced amacrine cells decreases. Conversely, knockdown of Nel expression by transposon-mediated introduction of RNA interference constructs results in decrease in RGC number and increase in the number of displaced amacrine cells. Modifications of Nel expression levels do not appear to affect proliferation of retinal progenitor cells, but they significantly alter the progression rate of RGC differentiation from the central retina to the periphery. Furthermore, Nel protects RGCs from apoptosis during retinal development. These results indicate that Nel positively regulates RGC production by promoting their differentiation and survival during development.

  6. ON and OFF retinal ganglion cells differentially regulate serotonergic and GABAergic activity in the dorsal raphe nucleus.

    PubMed

    Zhang, Ting; Huang, Lu; Zhang, Li; Tan, Minjie; Pu, Mingliang; Pickard, Gary E; So, Kwok-Fai; Ren, Chaoran

    2016-05-16

    The dorsal raphe nucleus (DRN), the major source of serotonergic input to the forebrain, receives excitatory input from the retina that can modulate serotonin levels and depressive-like behavior. In the Mongolian gerbil, retinal ganglion cells (RGCs) with alpha-like morphological and Y-like physiological properties innervate the DRN with ON DRN-projecting RGCs out numbering OFF DRN-projecting RGCs. The DRN neurons targeted by ON and OFF RGCs are unknown. To explore retino-raphe anatomical organization, retinal afferents labeled with Cholera toxin B were examined for association with the postsynaptic protein PSD-95. Synaptic associations between retinal afferents and DRN serotonergic and GABAergic neurons were observed. To explore retino-raphe functional organization, light-evoked c-fos expression was examined. Light significantly increased the number of DRN serotonergic and GABAergic cells expressing c-Fos. When ON RGCs were rendered silent while enhancing the firing rate of OFF RGCs, c-Fos expression was greatly increased in DRN serotonergic neurons suggesting that OFF DRN-projecting RGCs predominately activate serotonergic neurons whereas ON DRN-projecting RGCs mainly target GABAergic neurons. Direct glutamatergic retinal input to DRN 5-HT neurons contributes to the complex excitatory drive regulating these cells. Light, via the retinoraphe pathway can modify DRN 5-HT neuron activity which may play a role in modulating affective behavior.

  7. Progression of retinal ganglion cell loss in multiple sclerosis is associated with new lesions in the optic radiations.

    PubMed

    Klistorner, A; Graham, E C; Yiannikas, C; Barnett, M; Parratt, J; Garrick, R; Wang, C; You, Y; Graham, S L

    2017-08-10

    The mechanism of retinal ganglion cell and retinal nerve fiber layer loss in multiple sclerosis (MS) remains unknown. This study aimed to investigate the association between temporal retinal nerve fiber layer (tRNFL) thinning and disease activity in the brain determined by T2 lesions on magnetic resonance imaging (MRI). Fifty-five consecutive patients with relapsing-remitting MS and 25 controls were enrolled. All patients underwent annual optical coherence tomography and high-resolution MRI scans for tRNFL thickness and brain lesion volume analysis, respectively. Significant tRNFL thickness reduction was observed over the 3-year follow-up period at a relatively constant rate (1.02 μm/year). Thinning of tRNFL fibers was more prominent in younger patients (P = 0.01). The tRNFL loss was associated with new MRI lesions in the optic radiations (ORs). There was significantly greater tRNFL thinning in patients with new lesional activity in the ORs compared with patients with new lesions outside the ORs (P = 0.009). This study supports the notion that retrograde transneuronal degeneration caused by OR lesions might play a role in progressive retinal nerve fiber layer loss. In addition, the results of the study also indicate that the disease-related neurodegenerative changes in the retina start much earlier than the clinical diagnosis of MS. © 2017 EAN.

  8. Long Noncoding RNA-Sox2OT Knockdown Alleviates Diabetes Mellitus-Induced Retinal Ganglion Cell (RGC) injury.

    PubMed

    Li, Chao-Peng; Wang, Shu-Hong; Wang, Wen-Qi; Song, Shu-Guang; Liu, Xiu-Ming

    2017-03-01

    Retinal ganglion cell (RGC) injury is one of the important pathological features of diabetes-induced retinal neurodegeneration. Increasing attention has been paid to find strategies for protecting against RGC injury. Long noncoding RNAs (lncRNAs) have emerged as the key regulators of many cell functions. Here, we show that Sox2OT expression is significantly down-regulated in the retinas of STZ-induced diabetic mice and in the RGCs upon high glucose or oxidative stress. SOX2OT knockdown protects RGCs against high glucose-induced injury in vitro. Moreover, Sox2OT knockdown plays a neuroprotective role in diabetes-related retinal neurodegeneration in vivo. Sox2OT knockdown could regulate oxidative stress response in RGCs and diabetic mouse retinas. Sox2OT knockdown plays an anti-oxidative role via regulating NRF2/HO-1 signaling activity. Taken together, Sox2OT knockdown may be a therapeutic strategy for the prevention and treatment of diabetes-induced retinal neurodegeneration.

  9. Retinal ganglion cell topography and spatial resolution of two parrot species: budgerigar (Melopsittacus undulatus) and Bourke's parrot (Neopsephotus bourkii).

    PubMed

    Mitkus, Mindaugas; Chaib, Sandra; Lind, Olle; Kelber, Almut

    2014-05-01

    Retinal ganglion cell (RGC) isodensity maps indicate important regions in an animal's visual field. These maps can also be combined with measures of focal length to estimate the theoretical visual acuity. Here we present the RGC isodensity maps and anatomical spatial resolving power in three budgerigars (Melopsittacus undulatus) and two Bourke's parrots (Neopsephotus bourkii). Because RGCs were stacked in several layers, we modified the Nissl staining procedure to assess the cell number in the whole-mounted and cross-sectioned tissue of the same retinal specimen. The retinal topography showed surprising variation; however, both parrot species had an area centralis without discernable fovea. Budgerigars also had a putative area nasalis never reported in birds before. The peak RGC density was 22,300-34,200 cells/mm(2) in budgerigars and 18,100-38,000 cells/mm(2) in Bourke's parrots. The maximum visual acuity based on RGCs and focal length was 6.9 cyc/deg in budgerigars and 9.2 cyc/deg in Bourke's parrots. These results are lower than earlier behavioural estimates. Our findings illustrate that retinal topography is not a very fixed trait and that theoretical visual acuity estimations based on RGC density can be lower than the behavioural performance of the bird.

  10. Identification of Mesencephalic Astrocyte-Derived Neurotrophic Factor as a Novel Neuroprotective Factor for Retinal Ganglion Cells

    PubMed Central

    Gao, Feng-Juan; Wu, Ji-Hong; Li, Ting-Ting; Du, Shan-Shan; Wu, Qiang

    2017-01-01

    Mesencephalic astrocyte-derived neurotrophic factor (MANF), a newly discovered secreted neurotrophic factor, has been proven to not only protect dopaminergic neurons and other cell types but also regulate neuroinflammation and the immune response to promote tissue repair and regeneration. However, to date, there is no information regarding the relationship between MANF and retinal ganglion cells (RGCs) in the eye. In the current study, we first determined the expression of MANF in the retina and vitreous. Then, we examined the effect of MANF on RGCs using both in vivo and in vitro models and simultaneously explored the underlying neuroprotective mechanisms of MANF. Finally, we measured the concentrations of MANF in the vitreous of patients with different retinopathies. We demonstrated that MANF was highly expressed in RGCs and that exogenous MANF could protect RGCs from hypoxia-induced cell injury and apoptosis both in vitro and in vivo by preventing endoplasmic reticulum stress-mediated apoptosis. Furthermore, MANF can be detected in the vitreous humor, and the concentration changed under pathological conditions. Our results provide important evidence that MANF may be a potential therapeutic protein for a range of retinal pathologies in either the preclinical stage or after diagnosis to promote the survival of RGCs. Vitreous MANF may be a promising protein biomarker for the indirect assessment of retinal disorders, which could provide indirect evidence of retinal pathology. PMID:28367115

  11. ON and OFF retinal ganglion cells differentially regulate serotonergic and GABAergic activity in the dorsal raphe nucleus

    PubMed Central

    Zhang, Ting; Huang, Lu; Zhang, Li; Tan, Minjie; Pu, Mingliang; Pickard, Gary E.; So, Kwok-Fai; Ren, Chaoran

    2016-01-01

    The dorsal raphe nucleus (DRN), the major source of serotonergic input to the forebrain, receives excitatory input from the retina that can modulate serotonin levels and depressive-like behavior. In the Mongolian gerbil, retinal ganglion cells (RGCs) with alpha-like morphological and Y-like physiological properties innervate the DRN with ON DRN-projecting RGCs out numbering OFF DRN-projecting RGCs. The DRN neurons targeted by ON and OFF RGCs are unknown. To explore retino-raphe anatomical organization, retinal afferents labeled with Cholera toxin B were examined for association with the postsynaptic protein PSD-95. Synaptic associations between retinal afferents and DRN serotonergic and GABAergic neurons were observed. To explore retino-raphe functional organization, light-evoked c-fos expression was examined. Light significantly increased the number of DRN serotonergic and GABAergic cells expressing c-Fos. When ON RGCs were rendered silent while enhancing the firing rate of OFF RGCs, c-Fos expression was greatly increased in DRN serotonergic neurons suggesting that OFF DRN-projecting RGCs predominately activate serotonergic neurons whereas ON DRN-projecting RGCs mainly target GABAergic neurons. Direct glutamatergic retinal input to DRN 5-HT neurons contributes to the complex excitatory drive regulating these cells. Light, via the retinoraphe pathway can modify DRN 5-HT neuron activity which may play a role in modulating affective behavior. PMID:27181078

  12. Selectivity of direct and network-mediated stimulation of the retinal ganglion cells with epi-, sub- and intraretinal electrodes

    NASA Astrophysics Data System (ADS)

    Boinagrov, David; Pangratz-Fuehrer, Susanne; Goetz, Georges; Palanker, Daniel

    2014-04-01

    Objective. Intra-retinal placement of stimulating electrodes can provide close and stable proximity to target neurons. We assessed improvement in stimulation thresholds and selectivity of the direct and network-mediated retinal stimulation with intraretinal electrodes, compared to epiretinal and subretinal placements. Approach. Stimulation thresholds of the retinal ganglion cells (RGCs) in wild-type rat retina were measured using the patch-clamp technique. Direct and network-mediated responses were discriminated using various synaptic blockers. Main results. Three types of RGC responses were identified: short latency (SL, τ < 5 ms) originating in RGCs, medium latency (ML, 3 < τ < 70 ms) originating in the inner nuclear layer and long latency (LL, τ > 40 ms) originating in photoreceptors. Cathodic epiretinal stimulation exhibited the lowest threshold for direct RGC response and the highest direct selectivity (network/direct thresholds ratio), exceeding a factor of 3 with pulse durations below 0.5 ms. For network-mediated stimulation, the lowest threshold was obtained with anodic pulses in OPL position, and its network selectivity (direct/network thresholds ratio) increased with pulse duration, exceeding a factor of 4 at 10 ms. Latency of all three types of responses decreased with increasing strength of the stimulus. Significance. These results define the optimal range of pulse durations, pulse polarities and electrode placement for the retinal prostheses aiming at direct or network-mediated stimulation of RGCs.

  13. Impact of Morphometry, Myelinization and Synaptic Current Strength on Spike Conduction in Human and Cat Spiral Ganglion Neurons

    PubMed Central

    Rattay, Frank; Potrusil, Thomas; Wenger, Cornelia; Wise, Andrew K.; Glueckert, Rudolf; Schrott-Fischer, Anneliese

    2013-01-01

    Background Our knowledge about the neural code in the auditory nerve is based to a large extent on experiments on cats. Several anatomical differences between auditory neurons in human and cat are expected to lead to functional differences in speed and safety of spike conduction. Methodology/Principal Findings Confocal microscopy was used to systematically evaluate peripheral and central process diameters, commonness of myelination and morphology of spiral ganglion neurons (SGNs) along the cochlea of three human and three cats. Based on these morphometric data, model analysis reveales that spike conduction in SGNs is characterized by four phases: a postsynaptic delay, constant velocity in the peripheral process, a presomatic delay and constant velocity in the central process. The majority of SGNs are type I, connecting the inner hair cells with the brainstem. In contrast to those of humans, type I neurons of the cat are entirely myelinated. Biophysical model evaluation showed delayed and weak spikes in the human soma region as a consequence of a lack of myelin. The simulated spike conduction times are in accordance with normal interwave latencies from auditory brainstem response recordings from man and cat. Simulated 400 pA postsynaptic currents from inner hair cell ribbon synapses were 15 times above threshold. They enforced quick and synchronous spiking. Both of these properties were not present in type II cells as they receive fewer and much weaker (∼26 pA) synaptic stimuli. Conclusions/Significance Wasting synaptic energy boosts spike initiation, which guarantees the rapid transmission of temporal fine structure of auditory signals. However, a lack of myelin in the soma regions of human type I neurons causes a large delay in spike conduction in comparison with cat neurons. The absent myelin, in combination with a longer peripheral process, causes quantitative differences of temporal parameters in the electrically stimulated human cochlea compared to the cat

  14. Acute hyperglycemia-induced endothelial dysfunction in retinal arterioles in cats.

    PubMed

    Sogawa, Kenji; Nagaoka, Taiji; Izumi, Naohiro; Nakabayashi, Seigo; Yoshida, Akitoshi

    2010-05-01

    To investigate the effects of acute hyperglycemia on retinal microcirculation and endothelial function in cats and removal of superoxide to prevent retinal endothelial dysfunction from hyperglycemia. Hyperglycemia was induced by intravenous injection of 25% glucose to maintain the plasma glucose concentration at 30 mM. Laser Doppler velocimetry was used to measure the vessel diameter (D) and blood velocity (V) simultaneously and calculated retinal blood flow (RBF) in second-order retinal arterioles in cats. Intravitreous, endothelial-dependent vasodilator bradykinin (BK) and endothelium-independent vasodilator sodium nitroprusside (SNP) were administered into the vitreous cavity to evaluate endothelial function in the retinal arterioles. To control osmolality, 25% mannitol was administered the same way. Systemic hyperoxia was induced to noninvasively examine endothelial function during hyperglycemia. To determine the effect of the superoxide on the hyperglycemia-induced changes in the retinal circulation, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) was administered in drinking water for 14 days before the experiment. The D, V, and RBF increased with acute hyperglycemia and mannitol compared with baseline. BK-induced increases in D, V, and RBF significantly declined, whereas SNP-induced increases were unattenuated during acute hyperglycemia. Return of the decreased RBF to baseline after cessation of systemic hyperoxia was significantly (P < 0.05) inhibited by acute hyperglycemia. TEMPOL significantly (P < 0.05) prevented a decrease in the BK-induced increase in RBF during hyperglycemia. The results suggest that acute hyperglycemia increases RBF via increased osmolality and may cause retinal endothelial dysfunction partially via increased oxidative stress. Systemic hyperoxia can be used to noninvasively evaluate retinal endothelial function during hyperglycemia.

  15. An intraocular drug delivery system using targeted nanocarriers attenuates retinal ganglion cell degeneration.

    PubMed

    Zhao, Lei; Chen, Guojun; Li, Jun; Fu, Yingmei; Mavlyutov, Timur A; Yao, Annie; Nickells, Robert W; Gong, Shaoqin; Guo, Lian-Wang

    2017-02-10

    Glaucoma is a common blinding disease characterized by loss of retinal ganglion cells (RGCs). To date, there is no clinically available treatment directly targeting RGCs. We aim to develop an RGC-targeted intraocular drug delivery system using unimolecular micelle nanoparticles (unimNPs) to prevent RGC loss. The unimNPs were formed by single/individual multi-arm star amphiphilic block copolymer poly(amidoamine)-polyvalerolactone-poly(ethylene glycol) (PAMAM-PVL-PEG). While the hydrophobic PAMAM-PVL core can encapsulate hydrophobic drugs, the hydrophilic PEG shell provides excellent water dispersity. We conjugated unimNPs with the cholera toxin B domain (CTB) for RGC-targeting and with Cy5.5 for unimNP-tracing. To exploit RGC-protective sigma-1 receptor (S1R), we loaded unimNPs with an endogenous S1R agonist dehydroepiandrosterone (DHEA) as an FDA-approved model drug. These unimNPs produced a steady DHEA release in vitro for over two months at pH7.4. We then co-injected (mice, intraocular) unimNPs with the glutamate analog N-methyl-d-aspartate (NMDA), which is excito-toxic and induces RGC death. The CTB-conjugated unimNPs (i.e., targeted NPs) accumulated at the RGC layer and effectively preserved RGCs at least for 14days, whereas the unimNPs without CTB (i.e., non-targeted NPs) showed neither accumulation at nor protection of NMDA-treated RGCs. Consistent with S1R functions, targeted NPs relative to non-targeted NPs showed markedly better inhibitory effects on apoptosis and oxidative/inflammatory stresses in the RGC layer. Hence, the DHEA-loaded, CTB-conjugated unimNPs represent an RGC/S1R dual-targeted nanoplatform that generates an efficacious template for further development of a sustainable intraocular drug delivery system to protect RGCs, which may be applicable to treatments directed at glaucomatous pathology.

  16. Developmental maturation of passive electrical properties in retinal ganglion cells of rainbow trout.

    PubMed

    Picones, Arturo; Chung, S Clare; Korenbrot, Juan I

    2003-04-01

    We investigated the electrotonic and anatomical features of the dendritic arbor in developing retinal ganglion cells (RGCs). Cell anatomy was studied by filling individual cells with fluorescent, membrane-bound dyes and using computer-assisted image reconstruction. Electrotonic properties were characterized through an analysis of charging membrane currents measured with tight-seal electrodes in the whole-cell mode. We studied developing RGCs in the peripheral growth zone (PGZ) of a fish retina. The PGZ presents a developmental time-line ranging from pluripotent, proliferating cells at the extreme edge, to mature, fully developed retina more centrally. In the PGZ, RGCs mature through three histologically distinct zones (in developmental sequence): bulge, transition and mature zones. In the most peripheral three-quarters of the bulge zone, cells have rounded somas, lack dendritic extensions and some are coupled so that membrane-bound dyes traverse from one cell to its immediate neighbours. In the more central quarter of the bulge, cells' dendrites are few, short and of limited branching. In the transition zone dendritic arbors becomes progressively more expansive and branched and we present a morphometric analysis of these changes. Regardless of the size and branching pattern of the developing RGC dendritic arbor, the ratio of the diameters of parent and progeny dendrites at any branching nodes is well described by Rall's 3/2 power law. Given this anatomical feature, the RGC passive electrical properties are well described by an equivalent electrical circuit consisting of an isopotential cell body in parallel with a single equivalent cylinder of finite length. We measured the values of the electrical parameters that define this equivalent circuit in bulge, transition and mature RGCs. As RGCs develop the electrical properties of their dendritic arbor change in an orderly and tightly regulated manner, not randomly. Electrically, dendritic arbors develop along either of

  17. Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs) Are Necessary for Light Entrainment of Peripheral Clocks

    PubMed Central

    Mure, Ludovic S.; Massman, Logan J.; Purrier, Nicole; Panda, Satchidananda; Engeland, William C.

    2016-01-01

    Light is a powerful entrainer of circadian clocks in almost all eukaryotic organisms promoting synchronization of internal circadian rhythms with external environmental light-dark (LD) cycles. In mammals, the circadian system is organized in a hierarchical manner, in which a central pacemaker in the suprachiasmatic nucleus (SCN) synchronizes oscillators in peripheral tissues. Recent evidence demonstrates that photoentrainment of the SCN proceeds via signaling from a subpopulation of retinal ganglion cells (RGCs) which are melanopsin-expressing and intrinsically photosensitive (ipRGCs). However, it is still unclear whether photoentrainment of peripheral clocks is mediated exclusively by the ipRGC system or if signaling from RGCs that do not express melanopsin also plays a role. Here we have used genetic “silencing” of ipRGC neurotransmission in mice to investigate whether this photoreceptive system is obligatory for the photoentrainment of peripheral circadian clocks. Genetic silencing of ipRGC neurotransmission in mice was achieved by expression of tetanus toxin light chain in melanopsin-expressing cells (Opn4::TeNT mouse line). Rhythms of the clock gene Period 2 in various peripheral tissues were measured by crossbreeding Opn4::TeNT mice with PER2 luciferase knock-in mice (mPER2Luc). We found that in Opn4::TeNT mice the pupillary light reflex, light modulation of activity, and circadian photoentrainment of locomotor activity were severely impaired. Furthermore, ex vivo cultures from Opn4::TeNT, mPER2Luc mice of the adrenal gland, cornea, lung, liver, pituitary and spleen exhibited robust circadian rhythms of PER2::LUC bioluminescence. However, their peak bioluminescence rhythms were not aligned to the projected LD cycles indicating their lack of photic entrainment in vivo. Finally, we found that the circadian rhythm in adrenal corticosterone in Opn4::TeNT mice, as monitored by in vivo subcutaneous microdialysis, was desynchronized from environmental LD cycles

  18. A modified chronic ocular hypertension rat model for retinal ganglion cell neuroprotection.

    PubMed

    Zhong, Lichun

    2013-09-01

    This study aimed to modify a chronic ocular hypertension (OHT) rat model to screen for potential compounds to protect retinal ganglion cells (RGCs) from responding to increased intraocular pressure (IOP). A total of 266 rats were prepared and randomly grouped according to different time-points, namely, weeks 3, 8, 16, and 24. Rats were sedated and eye examination was performed to score as the corneal damage on a scale of 1 to 4. The OHT rat model was created via the injection of a hypertonic saline solution into the episcleral veins once weekly for two weeks. OHT was identified when the IOP at week 0 was [Symbol: see text] 6 mmHg than that at week -2 for the same eye. Viable RGCs were labeled by injecting 4% FluoroGold. Rats were sacrificed, and the eyes were enucleated and fixed. The fixed retinas were dissected to prepare flat whole-mounts. The viable RGCs were visualized and imaged. The IOP (mean ± SD) was calculated, and data were analyzed by the paired t-test and one-way ANOVA. The OHT model was created in 234 of 266 rats (87.97%), whereas 32 rats (12.03%) were removed from the study because of the absence of IOP elevation (11.28%) and/or corneal damage scores over 4 (0.75%). IOP was elevated by as much as 81.35% for 24 weeks. The average IOP was (16.68 ± 0.98) mmHg in non-OHT eyes (n = 234), but was (27.95 ± 0.97) mmHg in OHTeyes (n = 234). Viable RGCs in the OHT eyes were significantly decreased in a time-dependent manner by 29.41%, 38.24%, 55.32%, and 59.30% at weeks 3, 8, 16, and 24, respectively, as compared to viable RGCs in the non-OHT eyes (P < 0.05). The OHT model was successfully created in 88% of the rats. The IOP in the OHT eyes was elevated by approximately 81% for 24 weeks. The number of viable RGCs was decreased by 59% of the rats in a time-dependent manner. The modified OHT model may provide an effective and reliable method for screening drugs to protect RGCs from glaucoma.

  19. Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs) Are Necessary for Light Entrainment of Peripheral Clocks.

    PubMed

    Kofuji, Paulo; Mure, Ludovic S; Massman, Logan J; Purrier, Nicole; Panda, Satchidananda; Engeland, William C

    2016-01-01

    Light is a powerful entrainer of circadian clocks in almost all eukaryotic organisms promoting synchronization of internal circadian rhythms with external environmental light-dark (LD) cycles. In mammals, the circadian system is organized in a hierarchical manner, in which a central pacemaker in the suprachiasmatic nucleus (SCN) synchronizes oscillators in peripheral tissues. Recent evidence demonstrates that photoentrainment of the SCN proceeds via signaling from a subpopulation of retinal ganglion cells (RGCs) which are melanopsin-expressing and intrinsically photosensitive (ipRGCs). However, it is still unclear whether photoentrainment of peripheral clocks is mediated exclusively by the ipRGC system or if signaling from RGCs that do not express melanopsin also plays a role. Here we have used genetic "silencing" of ipRGC neurotransmission in mice to investigate whether this photoreceptive system is obligatory for the photoentrainment of peripheral circadian clocks. Genetic silencing of ipRGC neurotransmission in mice was achieved by expression of tetanus toxin light chain in melanopsin-expressing cells (Opn4::TeNT mouse line). Rhythms of the clock gene Period 2 in various peripheral tissues were measured by crossbreeding Opn4::TeNT mice with PER2 luciferase knock-in mice (mPER2Luc). We found that in Opn4::TeNT mice the pupillary light reflex, light modulation of activity, and circadian photoentrainment of locomotor activity were severely impaired. Furthermore, ex vivo cultures from Opn4::TeNT, mPER2Luc mice of the adrenal gland, cornea, lung, liver, pituitary and spleen exhibited robust circadian rhythms of PER2::LUC bioluminescence. However, their peak bioluminescence rhythms were not aligned to the projected LD cycles indicating their lack of photic entrainment in vivo. Finally, we found that the circadian rhythm in adrenal corticosterone in Opn4::TeNT mice, as monitored by in vivo subcutaneous microdialysis, was desynchronized from environmental LD cycles. Our

  20. High Pressure-Induced mtDNA Alterations in Retinal Ganglion Cells and Subsequent Apoptosis

    PubMed Central

    Zhang, Sheng-Hai; Gao, Feng-Juan; Sun, Zhong-Mou; Xu, Ping; Chen, Jun-Yi; Sun, Xing-Huai; Wu, Ji-Hong

    2016-01-01

    Purpose: Our previous study indicated that mitochondrial DNA (mtDNA) damage and mutations are crucial to the progressive loss of retinal ganglion cells (RGCs) in a glaucomatous rat model. In this study, we examined whether high pressure could directly cause mtDNA alterations and whether the latter could lead to mitochondrial dysfunction and RGC death. Methods: Primary cultured rat RGCs were exposed to 30 mm Hg of hydrostatic pressure (HP) for 12, 24, 48, 72, 96 and 120 h. mtDNA alterations and mtDNA repair/replication enzymes OGG1, MYH and polymerase gamma (POLG) expressions were also analyzed. The RGCs were then infected with a lentiviral small hairpin RNA (shRNA) expression vector targeting POLG (POLG-shRNA), and mtDNA alterations as well as mitochondrial function, including complex I/III activities and ATP production were subsequently studied at appropriate times. Finally, RGC apoptosis and the mitochondrial-apoptosis pathway-related protein cleaved caspase-3 were detected using a Terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay and western blotting, respectively. Results: mtDNA damage was observed as early as 48 h after the exposure of RGCs to HP. At 120 h after HP, mtDNA damage and mutations significantly increased, reaching >40% and 4.8 ± 0.3-fold, respectively, compared with the control values. Twelve hours after HP, the expressions of OGG1, MYH and POLG mRNA in the RGCs were obviously increased 5.02 ± 0.6-fold (p < 0.01), 4.3 ± 0.2-fold (p < 0.05), and 0.8 ± 0.09-fold (p < 0.05). Western blot analysis showed that the protein levels of the three enzymes decreased at 72 and 120 h after HP (p < 0.05). After interference with POLG-shRNA, the mtDNA damage and mutations were significantly increased (p < 0.01), while complex I/III activities gradually decreased (p < 0.05). Corresponding decreases in membrane potential and ATP production appeared at 5 and 6 days after POLG-shRNA transfection respectively (p < 0.05). Increases in the

  1. Comparative analysis of three purification protocols for retinal ganglion cells from rat.

    PubMed

    Gao, Fengjuan; Li, Tingting; Hu, Jianyan; Zhou, Xujiao; Wu, Jihong; Wu, Qiang

    2016-01-01

    To make comparative analyses of the common three purification protocols for retinal ganglion cells (RGCs), providing a solid practical basis for selecting the method for purifying RGCs for use in subsequent experiments. Rat RGCs were isolated and purified using three methods, including two-step immunopanning (TIP) separation, two-step immunopanning-magnetic (TIPM) separation, and flow cytometric (FC) separation. Immunocytochemical staining, quantitative real-time PCR, flow cytometry, electrophysiology, and Cell Counting Kit-8 (CCK-8) analyses were performed to compare the purity, yield, and viability of the RGCs. The RGC yields from the TIP, TIPM, and FC methods were 24.60±15.98 × 10(4), 5.28±4.42 × 10(4), and 5.4±2.7 × 10(3) per retina, respectively. We easily controlled the relative purity of the RGCs with the FC method and even reached 100% of the maximum expected purity. However, the RGC purity was only 80.97±5.45% and 95.41±3.23% using the TIP and TIPM methods, respectively. The contaminant cells were mainly large, star-shaped, glial fibrillary acidic protein (GFAP)-positive astrocytes and small, round, syntaxin 1-positive amacrine cells with multiple short neurites. The RGCs purified with FC could not be cultured successively in our study; however, the TIP-RGCs survived more than 20 days with good viability, while the TIPM-RGCs survived less than 9 days. The three protocols for purifying the RGCs each had its own pros and cons. The RGCs isolated by the TIP method exhibited the highest viability and yield but had low purity. The purity of the RGCs isolated with the FC method could reach approximately 100% but had a low yield and cell viability. The TIPM method was reliable and produced RGCs with considerable purity, yield, and viability. This study provides a solid practical basis for selecting the method for purifying RGCs for use in subsequent experiments.

  2. Delayed neurogenesis leads to altered specification of ventrotemporal retinal ganglion cells in albino mice

    PubMed Central

    2014-01-01

    Background Proper binocular vision depends on the routing at the optic chiasm of the correct proportion of retinal ganglion cell (RGC) axons that project to the same (ipsilateral) and opposite (contralateral) side of the brain. The ipsilateral RGC projection is reduced in mammals with albinism, a congenital disorder characterized by deficient pigmentation in the skin, hair, and eyes. Compared to the pigmented embryonic mouse retina, the albino embryonic mouse retina has fewer RGCs that express the zinc-finger transcription factor, Zic2, which is transiently expressed by RGCs fated to project ipsilaterally. Here, using Zic2 as a marker of ipsilateral RGCs, Islet2 as a marker of contralateral RGCs, and birthdating, we investigate spatiotemporal dynamics of RGC production as they relate to the phenotype of diminished ipsilateral RGC number in the albino retina. Results At embryonic day (E)15.5, fewer Zic2-positive (Zic2+) RGCs are found in the albino ventrotemporal (VT) retina compared with the pigmented VT retina, as we previously reported. However, the reduction in Zic2+ RGCs in the albino is not accompanied by a compensatory increase in Zic2-negative (Zic2−) RGCs, resulting in fewer RGCs in the VT retina at this time point. At E17.5, however, the number of RGCs in the VT region is similar in pigmented and albino retinae, implicating a shift in the timing of RGC production in the albino. Short-term birthdating assays reveal a delay in RGC production in the albino VT retina between E13 and E15. Specifically, fewer Zic2+ RGCs are born at E13 and more Zic2− RGCs are born at E15. Consistent with an increase in the production of Zic2− RGCs born at later ages, more RGCs at E17.5 express the contralateral marker, Islet2, in the albino VT retina compared with the pigmented retina. Conclusions A delay in neurogenesis in the albino retina is linked to the alteration of RGC subtype specification and consequently leads to the reduced ipsilateral projection that

  3. Assessment of retinal ganglion cell damage in glaucomatous optic neuropathy: Axon transport, injury and soma loss.

    PubMed

    Nuschke, Andrea C; Farrell, Spring R; Levesque, Julie M; Chauhan, Balwantray C

    2015-12-01

    Glaucoma is a disease characterized by progressive axonal pathology and death of retinal ganglion cells (RGCs), which causes structural changes in the optic nerve head and irreversible vision loss. Several experimental models of glaucomatous optic neuropathy (GON) have been developed, primarily in non-human primates and, more recently and commonly, in rodents. These models provide important research tools to study the mechanisms underlying glaucomatous damage. Moreover, experimental GON provides the ability to quantify and monitor risk factors leading to RGC loss such as the level of intraocular pressure, axonal health and the RGC population. Using these experimental models we are able to gain a better understanding of GON, which allows for the development of potential neuroprotective strategies. Here we review the advantages and disadvantages of the relevant and most often utilized methods for evaluating axonal degeneration and RGC loss in GON. Axonal pathology in GON includes functional disruption of axonal transport (AT) and structural degeneration. Horseradish peroxidase (HRP), rhodamine-B-isothiocyanate (RITC) and cholera toxin-B (CTB) fluorescent conjugates have proven to be effective reporters of AT. Also, immunohistochemistry (IHC) for endogenous AT-associated proteins is often used as an indicator of AT function. Similarly, structural degeneration of axons in GON can be investigated via changes in the activity and expression of key axonal enzymes and structural proteins. Assessment of axonal degeneration can be measured by direct quantification of axons, qualitative grading, or a combination of both methods. RGC loss is the most frequently quantified variable in studies of experimental GON. Retrograde tracers can be used to quantify RGC populations in rodents via application to the superior colliculus (SC). In addition, in situ IHC for RGC-specific proteins is a common method of RGC quantification used in many studies. Recently, transgenic mouse models

  4. Hyperbaric pressure and increased susceptibility to glutamate toxicity in retinal ganglion cells in vitro.

    PubMed

    Aihara, Makoto; Chen, Yi-Ning; Uchida, Saiko; Nakayama, Mao; Araie, Makoto

    2014-01-01

    To investigate the effect of hyperbaric pressure on purified retinal ganglion cells (RGCs) and the additive effect of hyperbaric pressure on glutamate-induced RGC death. An RGC primary culture from 8-day-old Wistar rats was prepared and cultured in a hyperbaric chamber. The RGC survival rate under various pressure conditions and with 5 or 25 µM of glutamate stimulation was determined and compared with that of RGCs under isobaric conditions. First, RGCs were cultured at atmospheric pressure (0 mmHg) and under hyperbaric pressure (+30 and +90 mmHg, with pressure fluctuations varying from 0 to +30 or +60 mmHg). Next, RGCs were cultured at +15, +30, and +90 mmHg with the addition of 5 or 25 µM of glutamate. The effects of N-Methyl-D-aspartic acid (NMDA) and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl)propanoic acid (AMPA)/kainate receptor antagonists, MK-801, and 6,7-dinitroquinoxaline-2,3-dione (DNQX), on cell survival were assessed. Additionally, types of cell death and the induction of Bcl-2-associated X protein (BAX) leading to apoptosis were studied under hyperbaric pressure conditions and/or with 5 µM of glutamate. RGC death was not induced under increasing or fluctuating pressure conditions. RGC death was induced by 25 µM of glutamate and increased as pressure increased. RGC death was not induced by 5 µM of glutamate but was induced by and increased with increasing pressure. MK-801 and DNQX significantly reduced glutamate-induced RGC death, and DNQX was more effective than MK-801. Under hyperbaric pressure conditions, the addition of 5 µM of glutamate resulted in the induction of apoptosis and BAX, which did not occur under hyperbaric pressure conditions or with the addition of glutamate alone. In a rat RGC culture, hyperbaric pressure alone did not induce RGC death but increased RGC susceptibility to glutamate toxicity, which may be of relevance to ocular diseases with pressure-induced RGC death.

  5. Hyperbaric pressure and increased susceptibility to glutamate toxicity in retinal ganglion cells in vitro

    PubMed Central

    Chen, Yi-Ning; Uchida, Saiko; Nakayama, Mao; Araie, Makoto

    2014-01-01

    Purpose To investigate the effect of hyperbaric pressure on purified retinal ganglion cells (RGCs) and the additive effect of hyperbaric pressure on glutamate-induced RGC death. Methods An RGC primary culture from 8-day-old Wistar rats was prepared and cultured in a hyperbaric chamber. The RGC survival rate under various pressure conditions and with 5 or 25 µM of glutamate stimulation was determined and compared with that of RGCs under isobaric conditions. First, RGCs were cultured at atmospheric pressure (0 mmHg) and under hyperbaric pressure (+30 and +90 mmHg, with pressure fluctuations varying from 0 to +30 or +60 mmHg). Next, RGCs were cultured at +15, +30, and +90 mmHg with the addition of 5 or 25 µM of glutamate. The effects of N-Methyl-D-aspartic acid (NMDA) and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl)propanoic acid (AMPA)/kainate receptor antagonists, MK-801, and 6,7-dinitroquinoxaline-2,3-dione (DNQX), on cell survival were assessed. Additionally, types of cell death and the induction of Bcl-2-associated X protein (BAX) leading to apoptosis were studied under hyperbaric pressure conditions and/or with 5 µM of glutamate. Results RGC death was not induced under increasing or fluctuating pressure conditions. RGC death was induced by 25 µM of glutamate and increased as pressure increased. RGC death was not induced by 5 µM of glutamate but was induced by and increased with increasing pressure. MK-801 and DNQX significantly reduced glutamate-induced RGC death, and DNQX was more effective than MK-801. Under hyperbaric pressure conditions, the addition of 5 µM of glutamate resulted in the induction of apoptosis and BAX, which did not occur under hyperbaric pressure conditions or with the addition of glutamate alone. Conclusion In a rat RGC culture, hyperbaric pressure alone did not induce RGC death but increased RGC susceptibility to glutamate toxicity, which may be of relevance to ocular diseases with pressure-induced RGC death. PMID:24826068

  6. Retinal nerve fibre layer, ganglion cell layer and choroid thinning in migraine with aura

    PubMed Central

    2014-01-01

    Background The aim of this study was to investigate the thickness of the retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), and choroid thickness (CT) in patients who have migraines, with and without aura, using spectral optical coherence tomography (OCT). Methods Forty-five patients who had migraines without aura (Group 1), 45 patients who had migraines with aura (Group 2), and 30 healthy participants (control group) were included in the study. Spectral OCT was used to measure the RNFL, GCL and CT values for all patients. Results The mean age of Group 1, Group 2, and the control group was 34.6 ± 4.3, 32.8 ± 4.9, and 31.8 ± 4.6 years, respectively. The mean attack frequency was 3.6/month in Group 1 and 3.7/month in Group 2. The mean age among the groups (p = 0.27) and number of attacks in migraine patients (p = 0.73) were not significantly different. There was significant thinning in the RNFL and GCL in Group 2 (p < 0.05, p < 0.001 respectively), while there were no significant differences in RNFL and GCL measurements between Group 1 and the control group (p > 0.05). All groups were significantly different from one another with respect to CT, with the most thinning observed in Group 2 (p < 0.001). When all migraine patients (without grouping) were compared with the control group, there were significant differences on all parameters: RNFL thickness, GCC thickness and CT (p < 0.05). Conclusions RNFL and GCL were significantly thinner in the migraine patients with aura as compared with both the migraine patients without aura and the control subjects. In migraine, both with aura and without aura, patients’ choroid thinning should be considered when evaluating ophthalmological findings. PMID:24885597

  7. Retinal and Macular Ganglion Cell Count Estimated With Optical Coherence Tomography RTVUE-100 as a Candidate Biomarker for Glaucoma.

    PubMed

    Rolle, Teresa; Dallorto, Laura; Bonetti, Beatrice

    2016-10-01

    To evaluate the ability of total and macular estimated retinal ganglion cell (RGC) counts to discriminate between healthy and glaucomatous eyes. To determine threshold markers of the estimated RGCs taking into account age dependence. This was a cross-sectional, observational study. The study group consisted of 176 eyes subdivided in three groups: 32 healthy, 91 preperimetric (PPG), and 53 primary open-angle glaucoma (POAG) eyes. The estimate of total and macular number of RGCs was obtained using a model described later. To account for the inverse correlation of RGC count with age, we considered two age subgroups (≤55 and >55 years) for both total and macular estimated RGC counts. We computed frequency distributions and receiver operating characteristic (ROC) curves to measure the discriminating ability and derive the cut-offs between two different conditions with their relative diagnostic parameters. The total and macular estimated RGC counts showed highly significant differences among the three groups (P < 0.0001). The estimated RGC counts performed fairly well in distinguishing healthy from glaucomatous (PPG+POAG) eyes (area under the curve [AUC] = 0.79-0.92) with no statistically significant difference between total and macular RGCs. The approach allowed a good discrimination also between PPG and POAG eyes (AUC = 0.86-0.92). Cutoffs for the older age bracket were found to be lower in all cases. Retinal ganglion cell counts estimated with empirical formulas with RTVue-100 could be used as a valid surrogate for neural losses in glaucoma.

  8. GABAergic and glycinergic pathways to goldfish retinal ganglion cells: an ultrastructural double label study

    SciTech Connect

    Muller, J.F.

    1987-01-01

    An ultrastructural double label has been employed to compare GABAergic and glycinergic systems in the inner plexiform layer (IPL) of the goldfish retina. Electron microscope autoradiography of /sup 3/H-GABA and /sup 3/H-glycine uptake was combined with retrograde HRP-labeling of ganglion cells. When surveyed for distribution, GABAergic and glycinergic synapses were found onto labeled ganglion cells throughout the IPL. This reinforces previous physiological work that described GABAergic and glycinergic influences on a variety of ganglion cells in goldfish and carp; These physiological effects often reflect direct inputs.

  9. Neuroprotection by α2-Adrenergic Receptor Stimulation after Excitotoxic Retinal Injury: A Study of the Total Population of Retinal Ganglion Cells and Their Distribution in the Chicken Retina.

    PubMed

    Galindo-Romero, Caridad; Harun-Or-Rashid, Mohammad; Jiménez-López, Manuel; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta; Hallböök, Finn

    2016-01-01

    We have studied the effect of α2-adrenergic receptor stimulation on the total excitotoxically injured chicken retinal ganglion cell population. N-methyl-D-aspartate (NMDA) was intraocularly injected at embryonic day 18 and Brn3a positive retinal ganglion cells (Brn3a+ RGCs) were counted in flat-mounted retinas using automated routines. The number and distribution of the Brn3a+ RGCs were analyzed in series of normal retinas from embryonic day 8 to post-hatch day 11 retinas and in retinas 7 or 14 days post NMDA lesion. The total number of Brn3a+ RGCs in the post-hatch retina was approximately 1.9x106 with a density of approximately 9.2x103 cells/mm2. The isodensity maps of normal retina showed that the density decreased with age as the retinal size increased. In contrast to previous studies, we did not find any specific region with increased RGC density, rather the Brn3a+ RGCs were homogeneously distributed over the central retina with decreasing density in the periphery and in the region of the pecten oculli. Injection of 5-10 μg NMDA caused 30-50% loss of Brn3a+ cells and the loss was more severe in the dorsal than in the ventral retina. Pretreatment with brimonidine reduced the loss of Brn3a+ cells both 7 and 14 days post lesion and the protective effect was higher in the dorsal than in the ventral retina. We conclude that α2-adrenergic receptor stimulation reduced the impact of the excitotoxic injury in chicken similarly to what has been shown in mammals. Furthermore, the data show that the RGCs are evenly distributed over in the retina, which challenges previous results that indicate the presence of specific high RGC-density regions of the chicken retina.

  10. Neuroprotection by α2-Adrenergic Receptor Stimulation after Excitotoxic Retinal Injury: A Study of the Total Population of Retinal Ganglion Cells and Their Distribution in the Chicken Retina

    PubMed Central

    Galindo-Romero, Caridad; Harun-Or-Rashid, Mohammad; Jiménez-López, Manuel; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

    2016-01-01

    We have studied the effect of α2-adrenergic receptor stimulation on the total excitotoxically injured chicken retinal ganglion cell population. N-methyl-D-aspartate (NMDA) was intraocularly injected at embryonic day 18 and Brn3a positive retinal ganglion cells (Brn3a+ RGCs) were counted in flat-mounted retinas using automated routines. The number and distribution of the Brn3a+ RGCs were analyzed in series of normal retinas from embryonic day 8 to post-hatch day 11 retinas and in retinas 7 or 14 days post NMDA lesion. The total number of Brn3a+ RGCs in the post-hatch retina was approximately 1.9x106 with a density of approximately 9.2x103 cells/mm2. The isodensity maps of normal retina showed that the density decreased with age as the retinal size increased. In contrast to previous studies, we did not find any specific region with increased RGC density, rather the Brn3a+ RGCs were homogeneously distributed over the central retina with decreasing density in the periphery and in the region of the pecten oculli. Injection of 5–10 μg NMDA caused 30–50% loss of Brn3a+ cells and the loss was more severe in the dorsal than in the ventral retina. Pretreatment with brimonidine reduced the loss of Brn3a+ cells both 7 and 14 days post lesion and the protective effect was higher in the dorsal than in the ventral retina. We conclude that α2-adrenergic receptor stimulation reduced the impact of the excitotoxic injury in chicken similarly to what has been shown in mammals. Furthermore, the data show that the RGCs are evenly distributed over in the retina, which challenges previous results that indicate the presence of specific high RGC-density regions of the chicken retina. PMID:27611432

  11. Mesenchymal stem cells attenuate hydrogen peroxide-induced oxidative stress and enhance neuroprotective effects in retinal ganglion cells.

    PubMed

    Cui, Yi; Xu, Nuo; Xu, Wei; Xu, Guoxing

    2017-04-01

    The apoptosis of retinal ganglion cells leads to visual impairment and blindness in ocular neurodegenerative diseases, especially in diabetic retinopathy (DR). Mounting evidence suggests that oxidative stress contributes to the pathogenesis of DR. In the present study, we investigated whether bone mesenchymal stem cells (BMSCs) have protective ability to relieve hydrogen peroxide (H2O2)-induced injury on retinal ganglion cells in vitro. An immortalized retinal ganglion cells, RGC-5 cells, were exposed to an indicated concentration of H2O2 for 24 h. Cell viability was analyzed by CCK-8 assay to find out a certain concentration to build H2O2 oxidative damage model. Morphological changes in RGC-5 cells were observed under optical microscope, and cell apoptosis was detected with Hoechst fluorescence staining. Then, BMSCs were co-cultured with RGC-5 cells in a transwell culture system for 24 h and 48 h. Flow cytometry was performed to qualify the apoptosis rate of RGC-5 cells. Conditioned medium was collected for evaluation the inflammatory cytokines by ELISA. The content of intracellular malondialdehyde (MDA) and superoxide dismutase (SOD) was assayed by thiobarbituric acid and xanthine oxidase method, respectively. qRT-PCR and ELISA were conducted for analysis of the expression changes in brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), respectively. After H2O2 exposure, the morphological varieties were observed as cytoplasm shrinking and paramorphia together with nuclear gathering. Meanwhile, the apoptotic cells had hyperfluorescence with Hoechst 33258 staining. Co-culture with BMSCs significantly inhibited retinal cell death. It was found that BMSCs reduced H2O2-induced inflammatory factors IL-1β and TNF-α, down-regulated intracellular oxidant factor MDA, up-regulated intracellular antioxidant factor SOD, and increased neurotrophins BDNF and CNTF expression. BMSCs may enhance protective effect of RGC-5 cells in H2O2-induced

  12. Ionic mechanisms involved in the release of /sup 3/H-norepinephrine from the cat superior cervical ganglion

    SciTech Connect

    Alder-Graschinsky, E.; Filinger, E.J.; Martinez, A.E.

    1984-02-27

    It has previously been reported that in the isolated cat superior cervical ganglion (SCG) labeled with tritiated norepinephrine (/sup 3/H-NE), the stimulation of the preganglionic trunk at 10 Hz as well as the exposure to 100 ..mu..M exogenous acetylcholine (ACh), produced a Ca/sup + +/-dependent release of /sup 3/H-NE. The present results show that a Ca/sup + +/-dependent release of /sup 3/H-NE was produced also by exposure to either 50 ..mu..M veratridine or 60 mM KCl. Tetrodotoxin (0.5 ..mu..M) abolished the release of /sup 3/H-NE induced by preganglionic stimulation, ACh and veratridine but did not modify the release evoked by KCl. The metabolic distribution of the radioactivity released by the different depolarizing stimuli showed that the /sup 3/H-NE was collected mainly unmetabolized. In the cat SCG neither the release of /sup 3/H-NE evoked by KCl nor the endogenous content of NE was modified by pretreatment with 6-OH-dopamine (6-OH-DA). On the other hand, this chemical sympathectomy depleted the endogenous content of NE in the cat nictitating membrane, whose nerve terminals arise from the SCG. The data presented suggest that the depolarization-coupled release of NE from the cat SCG involves structures that are different to nerve terminals and that contain Na/sup +/ channels as well as Ca/sup + +/.

  13. Ionic mechanisms involved in the release of /sup 3/H-norepinephrine from the cat superior cervical ganglion

    SciTech Connect

    Adler-Graschinsky, E.; Filinger, E.J.; Martinez, A.E.

    1984-02-27

    It has previously been reported that in the isolated cat superior cervical ganglion (SCG) labeled with tritiated norepinephrine (/sup 3/H-NE), the stimulation of the preganglionic trunk at 10 Hz as well as the exposure to 100 ..mu..M exogenous acetylcholine (ACh), produced a Ca/sup + +/-dependent release of /sup 3/H-NE. The present results show that a Ca/sup + +/-dependent release of /sup 3/H-NE was produced also by exposure to either 50 ..mu..M veratridine or 60 mM KCl. Tetrodotoxin (0.5 ..mu..M) abolished the release of /sup 3/H-NE induced by preganglionic stimulation, ACh and veratridine but did not modify the release evoked by KCl. The metabolic distribution of the radioactivity released by the different depolarizing stimuli showed that the /sup 3/H-NE was collected mainly unmetabolized. In the cat SCG neither the release of /sup 3/H-NE evoked by KCl nor the endogenous content of NE was modified by pretreatment with 6-OH-dopamine (6-OH-DA). On the other hand, this chemical sympathectomy depleted the endogenous content of NE in the cat nictitating membrane, whose nerve terminals arise from the SCG. The data presented suggest that the depolarization-coupled release of NE from the cat SCG involves structure that are different to nerve terminals and that contain Na/sup +/ channels as well as Ca/sup + +/ channels.

  14. Differential Calcium Signaling Mediated by Voltage-Gated Calcium Channels in Rat Retinal Ganglion Cells and Their Unmyelinated Axons

    PubMed Central

    Sargoy, Allison; Sun, Xiaoping

    2014-01-01

    Aberrant calcium regulation has been implicated as a causative factor in the degeneration of retinal ganglion cells (RGCs) in numerous injury models of optic neuropathy. Since calcium has dual roles in maintaining homeostasis and triggering apoptotic pathways in healthy and injured cells, respectively, investigation of voltage-gated Ca channel (VGCC) regulation as a potential strategy to reduce the loss of RGCs is warranted. The accessibility and structure of the retina provide advantages for the investigation of the mechanisms of calcium signalling in both the somata of ganglion cells as well as their unmyelinated axons. The goal of the present study was to determine the distribution of VGCC subtypes in the cell bodies and axons of ganglion cells in the normal retina and to define their contribution to calcium signals in these cellular compartments. We report L-type Ca channel α1C and α1D subunit immunoreactivity in rat RGC somata and axons. The N-type Ca channel α1B subunit was in RGC somata and axons, while the P/Q-type Ca channel α1A subunit was only in the RGC somata. We patch clamped isolated ganglion cells and biophysically identified T-type Ca channels. Calcium imaging studies of RGCs in wholemounted retinas showed that selective Ca channel antagonists reduced depolarization-evoked calcium signals mediated by L-, N-, P/Q- and T-type Ca channels in the cell bodies but only by L-type Ca channels in the axons. This differential contribution of VGCC subtypes to calcium signals in RGC somata and their axons may provide insight into the development of target-specific strategies to spare the loss of RGCs and their axons following injury. PMID:24416240

  15. P2X7 receptor activation mediates retinal ganglion cell death in a human retina model of ischemic neurodegeneration.

    PubMed

    Niyadurupola, Nuwan; Sidaway, Peter; Ma, Ning; Rhodes, Jeremy D; Broadway, David C; Sanderson, Julie

    2013-03-01

    There is evidence implicating ischemia and excitotoxicity in the pathogenesis of glaucoma. ATP-mediated excitotoxicity via activation of the P2X7 receptor (P2X7R) has been proposed to play a role in retinal ganglion cell (RGC) degeneration in this disease. The aim of this research was to determine whether stimulation of the P2X7R mediated ischemia-induced RGC death in the human retina. Human organotypic retinal cultures were exposed to the P2X7R agonist 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP) and simulated ischemia (oxygen/glucose deprivation) in the presence or absence of the P2X7R antagonist, Brilliant Blue G (BBG). Neuronal death in the RGC layer was quantified by neuronal nuclei (NeuN)-positive cell counts and quantitative real-time PCR for THY-1 mRNA. The P2X7R was localized by immunohistochemistry and P2X7R mRNA profiling using a cryosectioning technique. P2X7R stimulation by BzATP (100 μM) induced loss of RGC markers in human organotypic retinal cultures (HORCs), which was inhibited by BBG (1 μM). Simulated ischemia led to loss of RGCs that was also inhibited by BBG, indicating that ischemia-induced RGC degeneration was mediated by the P2X7R. The P2X7R was immunolocalized to the outer and inner plexiform layers of the human retina, and P2X7R mRNA expression was confirmed in the inner retina and ganglion cell layer. These studies demonstrated that stimulation of the P2X7R can mediate RGC death and that this mechanism plays a role in ischemia-induced neurodegeneration in the human retina.

  16. Comparison of the Pattern of Retinal Ganglion Cell Damage Between Patients With Compressive and Glaucomatous Optic Neuropathies.

    PubMed

    Lee, Eun Ji; Yang, Hee Kyung; Kim, Tae-Woo; Hwang, Jeong-Min; Kim, Young-Hoon; Kim, Chae-Yong

    2015-11-01

    To compare the patterns of retinal ganglion cell (RGC) damage in the macular and peripapillary areas in compressive optic neuropathy (CON) and glaucomatous optic neuropathy (GON) using spectral-domain optical coherence tomography (SD-OCT), and to determine the usefulness of SD-OCT macular and peripapillary analysis in discriminating between CON and GON. Sixty-three eyes with CON, 68 eyes with GON, and 73 healthy control eyes were included. Spectral-domain OCT scanning of the circumpapillary and macular area was performed to measure the global and six-sector thicknesses of the circumpapillary retinal nerve fiber layer (cpRNFL), and the macular retinal nerve fiber layer (mRNFL) and macular ganglion cell layer (mGCL) thicknesses in the nine macular subfields as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS). Compared to the healthy eyes, the mRNFL was significantly thinner in six ETDRS subfields (inner and outer subfields of superior, nasal, and inferior areas) in CON, but in only two subfields (outer-inferior and outer-temporal subfields) in GON. The mGCL was thinner in all nine subfields in CON, but in only four subfields (inner and outer subfields of inferior and temporal areas) in GON. The temporal cpRNFL was significantly thinner in CON but was not involved in GON. The macular parameters performed better than cpRNFL parameters in discriminating between the CON and GON. Distinct differences in the patterns of RGC damage in the macular and peripapillary areas were found between CON and GON. Evaluation of the macular RGC damage may be a useful adjunct for distinguishing CON from GON when optic disc and visual field examinations are inconclusive.

  17. Optical Detection of Early Damage in Retinal Ganglion Cells in a Mouse Model of Partial Optic Nerve Crush Injury

    PubMed Central

    Yi, Ji; Puyang, Zhen; Feng, Liang; Duan, Lian; Liang, Peiji; Backman, Vadim; Liu, Xiaorong; Zhang, Hao F.

    2016-01-01

    Purpose Elastic light backscattering spectroscopy (ELBS) has exquisite sensitivity to the ultrastructural properties of tissue and thus has been applied to detect various diseases associated with ultrastructural alterations in their early stages. This study aims to test whether ELBS can detect early damage in retinal ganglion cells (RGCs). Methods We used a mouse model of partial optic nerve crush (pONC) to induce rapid RGC death. We confirmed RGC loss by axon counting and characterized the changes in retinal morphology by optical coherence tomography (OCT) and in retinal function by full-field electroretinogram (ERG), respectively. To quantify the ultrastructural properties, elastic backscattering spectroscopic analysis was implemented in the wavelength-dependent images recorded by reflectance confocal microscopy. Results At 3 days post-pONC injury, no significant change was found in the thickness of the RGC layer or in the mean amplitude of the oscillatory potentials measured by OCT and ERG, respectively; however, we did observe a significantly decreased number of axons compared with the controls. At 3 days post-pONC, we used ELBS to calculate the ultrastructural marker (D), the shape factor quantifying the shape of the local mass density correlation functions. It was significantly reduced in the crushed eyes compared with the controls, indicating the ultrastructural fragmentation in the crushed eyes. Conclusions Elastic light backscattering spectroscopy detected ultrastructural neuronal damage in RGCs following the pONC injury when OCT and ERG tests appeared normal. Our study suggests a potential clinical method for detecting early neuronal damage prior to anatomical alterations in the nerve fiber and ganglion cell layers. PMID:27784071

  18. Quantitative and Topographical Analysis of the Losses of Cone Photoreceptors and Retinal Ganglion Cells Under Taurine Depletion.

    PubMed

    Hadj-Saïd, Wahiba; Froger, Nicolas; Ivkovic, Ivana; Jiménez-López, Manuel; Dubus, Élisabeth; Dégardin-Chicaud, Julie; Simonutti, Manuel; Quénol, César; Neveux, Nathalie; Villegas-Pérez, María Paz; Agudo-Barriuso, Marta; Vidal-Sanz, Manuel; Sahel, Jose-Alain; Picaud, Serge; García-Ayuso, Diego

    2016-09-01

    Taurine depletion is known to induce photoreceptor degeneration and was recently found to also trigger retinal ganglion cell (RGC) loss similar to the retinal toxicity of vigabatrin. Our objective was to study the topographical loss of RGCs and cone photoreceptors, with a distinction between the two cone types (S- and L- cones) in an animal model of induced taurine depletion. We used the taurine transporter (Tau-T) inhibitor, guanidoethane sulfonate (GES), to induce taurine depletion at a concentration of 1% in the drinking water. Spectral-domain optical coherence tomography (SD-OCT) and electroretinograms (ERG) were performed on animals after 2 months of GES treatment administered through the drinking water. Retinas were dissected as wholemounts and immunodetection of Brn3a (RGC), S-opsin (S-cones), and L-opsin (L-cones) was performed. The number of Brn3a+ RGCs, and L- and S-opsin+ cones was automatically quantified and their retinal distribution studied using isodensity maps. The treatment resulted in a significant reduction in plasma taurine levels and a profound dysfunction of visual performance as shown by ERG recordings. Optical coherence tomography analysis revealed that the retina was thinner in the taurine-depleted group. S-opsin+cones were more affected (36%) than L-opsin+cones (27%) with greater cone cell loss in the dorsal area whereas RGC loss (12%) was uniformly distributed. This study confirms that taurine depletion causes RGC and cone loss. Electroretinograms results show that taurine depletion induces retinal dysfunction in photoreceptors and in the inner retina. It establishes a gradient of cell loss depending on the cell type from S-opsin+cones, L-opsin+cones, to RGCs. The greater cell loss in the dorsal retina and of the S-cone population may underline different cellular mechanisms of cellular degeneration and suggests that S-cones may be more sensitive to light-induced retinal toxicity enhanced by the taurine depletion.

  19. Activation and inhibition of retinal ganglion cells in response to epiretinal electrical stimulation: a computational modelling study

    NASA Astrophysics Data System (ADS)

    Abramian, Miganoosh; Lovell, Nigel H.; Morley, John W.; Suaning, Gregg J.; Dokos, Socrates

    2015-02-01

    Objective. Retinal prosthetic devices aim to restore sight in visually impaired people by means of electrical stimulation of surviving retinal ganglion cells (RGCs). This modelling study aims to demonstrate that RGC inhibition caused by high-intensity cathodic pulses greatly influences their responses to epiretinal electrical stimulation and to investigate the impact of this inhibition on spatial activation profiles as well as their implications for retinal prosthetic device design. Another aim is to take advantage of this inhibition to reduce axonal activation in the nerve fibre layer. Approach. A three-dimensional finite-element model of epiretinal electrical stimulation was utilized to obtain RGC activation and inhibition threshold profiles for a range of parameters. Main results. RGC activation and inhibition thresholds were highly dependent on cell and stimulus parameters. Activation thresholds were 1.5, 3.4 and 11.3 μA for monopolar electrodes with 5, 20 and 50 μm radii, respectively. Inhibition to activation threshold ratios were mostly within the range 2-10. Inhibition significantly altered spatial patterns of RGC activation. With concentric electrodes and appropriately high levels of stimulus amplitudes, activation of passing axons was greatly reduced. Significance. RGC inhibition significantly impacts their spatial activation profiles, and therefore it most likely influences patterns of perceived phosphenes induced by retinal prosthetic devices. Thus this inhibition should be taken into account in future studies concerning retinal prosthesis development. It might be possible to utilize this inhibitory effect to bypass activation of passing axons and selectively stimulate RGCs near their somas and dendrites to achieve more localized phosphenes.

  20. BDNF Promotes Axon Branching of Retinal Ganglion Cells via miRNA-132 and p250GAP

    PubMed Central

    Marler, Katharine J.; Suetterlin, Philipp; Dopplapudi, Asha; Rubikaite, Aine; Adnan, Jihad; Maiorano, Nicola A.; Lowe, Andrew S.; Thompson, Ian D.; Pathania, Manav; Bordey, Angelique; Fulga, Tudor; Van Vactor, David L.; Hindges, Robert

    2014-01-01

    A crucial step in the development of the vertebrate visual system is the branching of retinal ganglion cell (RGC) axons within their target, the superior colliculus/tectum. A major player in this process is the neurotrophin brain-derived neurotrophic factor (BDNF). However, the molecular basis for the signaling pathways mediating BDNF action is less well understood. As BDNF exerts some of its functions by controlling the expression of microRNAs (miRNAs), we investigated whether miRNAs are also involved in BDNF-mediated retinal axon branching. Here, we demonstrate that the expression pattern of miRNA-132 in the retina is consistent with its involvement in this process, and that BDNF induces the upregulation of miRNA-132 in retinal cultures. Furthermore, in vitro gain-of-function and loss-of-function approaches in retinal cultures reveal that miRNA-132 mediates axon branching downstream of BDNF. A known target of miRNA-132 is the Rho family GTPase-activating protein, p250GAP. We find that p250GAP is expressed in RGC axons and mediates the effects of miRNA-132 in BDNF-induced branching. BDNF treatment or overexpression of miRNA-132 leads to a reduction in p250GAP protein levels in retinal cultures, whereas the overexpression of p250GAP abolishes BDNF-induced branching. Finally, we used a loss-of-function approach to show that miRNA-132 affects the maturation of RGC termination zones in the mouse superior colliculus in vivo, while their topographic targeting remains intact. Together, our data indicate that BDNF promotes RGC axon branching during retinocollicular/tectal map formation via upregulation of miRNA-132, which in turn downregulates p250GAP. PMID:24431455

  1. BDNF promotes axon branching of retinal ganglion cells via miRNA-132 and p250GAP.

    PubMed

    Marler, Katharine J; Suetterlin, Philipp; Dopplapudi, Asha; Rubikaite, Aine; Adnan, Jihad; Maiorano, Nicola A; Lowe, Andrew S; Thompson, Ian D; Pathania, Manav; Bordey, Angelique; Fulga, Tudor; Van Vactor, David L; Hindges, Robert; Drescher, Uwe

    2014-01-15

    A crucial step in the development of the vertebrate visual system is the branching of retinal ganglion cell (RGC) axons within their target, the superior colliculus/tectum. A major player in this process is the neurotrophin brain-derived neurotrophic factor (BDNF). However, the molecular basis for the signaling pathways mediating BDNF action is less well understood. As BDNF exerts some of its functions by controlling the expression of microRNAs (miRNAs), we investigated whether miRNAs are also involved in BDNF-mediated retinal axon branching. Here, we demonstrate that the expression pattern of miRNA-132 in the retina is consistent with its involvement in this process, and that BDNF induces the upregulation of miRNA-132 in retinal cultures. Furthermore, in vitro gain-of-function and loss-of-function approaches in retinal cultures reveal that miRNA-132 mediates axon branching downstream of BDNF. A known target of miRNA-132 is the Rho family GTPase-activating protein, p250GAP. We find that p250GAP is expressed in RGC axons and mediates the effects of miRNA-132 in BDNF-induced branching. BDNF treatment or overexpression of miRNA-132 leads to a reduction in p250GAP protein levels in retinal cultures, whereas the overexpression of p250GAP abolishes BDNF-induced branching. Finally, we used a loss-of-function approach to show that miRNA-132 affects the maturation of RGC termination zones in the mouse superior colliculus in vivo, while their topographic targeting remains intact. Together, our data indicate that BDNF promotes RGC axon branching during retinocollicular/tectal map formation via upregulation of miRNA-132, which in turn downregulates p250GAP.

  2. Inhibition of p75(NTR) in glia potentiates TrkA-mediated survival of injured retinal ganglion cells.

    PubMed

    Lebrun-Julien, Frédéric; Morquette, Barbara; Douillette, Annie; Saragovi, H Uri; Di Polo, Adriana

    2009-04-01

    Little is known about the molecular mechanisms that limit the ability of retinal neurons to respond to neurotrophic factor stimulation following axonal injury. In the adult retina, nerve growth factor (NGF) binds to TrkA (expressed by neurons) and p75(NTR) (expressed by Müller glia), but fails to promote the survival of axotomized retinal ganglion cells (RGCs). We addressed the functional role of TrkA and p75(NTR) in this lack of survival by using peptidomimetic agonistic or antagonistic ligands specific for each receptor. While administration of exogenous NGF failed to rescue axotomized RGCs, administration of selective TrkA agonists led to robust neuroprotection. Surprisingly, we found a remarkable survival of axotomized RGCs following pharmacological inhibition of p75(NTR) or in p75(NTR) knockout mice. Combination of NGF or TrkA agonists with p75(NTR) antagonists further potentiated RGC neuroprotection in vivo, an effect that was greater than each treatment alone. NGF can therefore be neuroprotective when acting on neuronal TrkA receptors but engagement of p75(NTR) on glial cells antagonizes this effect. Our data reveal a novel mechanism by which p75(NTR) expressed on retinal glia can profoundly influence neuronal survival.

  3. Two transcription factors, Pou4f2 and Isl1, are sufficient to specify the retinal ganglion cell fate.

    PubMed

    Wu, Fuguo; Kaczynski, Tadeusz J; Sethuramanujam, Santhosh; Li, Renzhong; Jain, Varsha; Slaughter, Malcolm; Mu, Xiuqian

    2015-03-31

    As with other retinal cell types, retinal ganglion cells (RGCs) arise from multipotent retinal progenitor cells (RPCs), and their formation is regulated by a hierarchical gene-regulatory network (GRN). Within this GRN, three transcription factors--atonal homolog 7 (Atoh7), POU domain, class 4, transcription factor 2 (Pou4f2), and insulin gene enhancer protein 1 (Isl1)--occupy key node positions at two different stages of RGC development. Atoh7 is upstream and is required for RPCs to gain competence for an RGC fate, whereas Pou4f2 and Isl1 are downstream and regulate RGC differentiation. However, the genetic and molecular basis for the specification of the RGC fate, a key step in RGC development, remains unclear. Here we report that ectopic expression of Pou4f2 and Isl1 in the Atoh7-null retina using a binary knockin-transgenic system is sufficient for the specification of the RGC fate. The RGCs thus formed are largely normal in gene expression, survive to postnatal stages, and are physiologically functional. Our results indicate that Pou4f2 and Isl1 compose a minimally sufficient regulatory core for the RGC fate. We further conclude that during development a core group of limited transcription factors, including Pou4f2 and Isl1, function downstream of Atoh7 to determine the RGC fate and initiate RGC differentiation.

  4. Frequency-dependent reduction of voltage-gated sodium current modulates retinal ganglion cell response rate to electrical stimulation

    NASA Astrophysics Data System (ADS)

    Tsai, David; Morley, John W.; Suaning, Gregg J.; Lovell, Nigel H.

    2011-10-01

    The ability to elicit visual percepts through electrical stimulation of the retina has prompted numerous investigations examining the feasibility of restoring sight to the blind with retinal implants. The therapeutic efficacy of these devices will be strongly influenced by their ability to elicit neural responses that approximate those of normal vision. Retinal ganglion cells (RGCs) can fire spikes at frequencies greater than 200 Hz when driven by light. However, several studies using isolated retinas have found a decline in RGC spiking response rate when these cells were stimulated at greater than 50 Hz. It is possible that the mechanism responsible for this decline also contributes to the frequency-dependent 'fading' of electrically evoked percepts recently reported in human patients. Using whole-cell patch clamp recordings of rabbit RGCs, we investigated the causes for the spiking response depression during direct subretinal stimulation of these cells at 50-200 Hz. The response depression was not caused by inhibition arising from the retinal network but, instead, by a stimulus-frequency-dependent decline of RGC voltage-gated sodium current. Under identical experimental conditions, however, RGCs were able to spike at high frequency when driven by light stimuli and intracellular depolarization. Based on these observations, we demonstrated a technique to prevent the spiking response depression.

  5. Vaccination for protection of retinal ganglion cells against death from glutamate cytotoxicity and ocular hypertension: Implications for glaucoma

    NASA Astrophysics Data System (ADS)

    Schori, Hadas; Kipnis, Jonathan; Yoles, Eti; Woldemussie, Elizabeth; Ruiz, Guadalupe; Wheeler, Larry A.; Schwartz, Michal

    2001-03-01

    Our group recently demonstrated that autoimmune T cells directed against central nervous system-associated myelin antigens protect neurons from secondary degeneration. We further showed that the synthetic peptide copolymer 1 (Cop-1), known to suppress experimental autoimmune encephalomyelitis, can be safely substituted for the natural myelin antigen in both passive and active immunization for neuroprotection of the injured optic nerve. Here we attempted to determine whether similar immunizations are protective from retinal ganglion cell loss resulting from a direct biochemical insult caused, for example, by glutamate (a major mediator of degeneration in acute and chronic optic nerve insults) and in a rat model of ocular hypertension. Passive immunization with T cells reactive to myelin basic protein or active immunization with myelin oligodendrocyte glycoprotein-derived peptide, although neuroprotective after optic nerve injury, was ineffective against glutamate toxicity in mice and rats. In contrast, the number of surviving retinal ganglion cells per square millimeter in glutamate-injected retinas was significantly larger in mice immunized 10 days previously with Cop-1 emulsified in complete Freund's adjuvant than in mice injected with PBS in the same adjuvant (2,133 ± 270 and 1,329 ± 121, respectively, mean ± SEM; P < 0.02). A similar pattern was observed when mice were immunized on the day of glutamate injection (1,777 ± 101 compared with 1,414 ± 36; P <0.05), but not when they were immunized 48h later. These findings suggest that protection from glutamate toxicity requires reinforcement of the immune system by antigens that are different from those associated with myelin. The use of Cop-1 apparently circumvents this antigen specificity barrier. In the rat ocular hypertension model, which simulates glaucoma, immunization with Cop-1 significantly reduced the retinal ganglion cell loss from 27.8%±6.8% to 4.3%±1.6%, without affecting the intraocular pressure

  6. Characteristics of retinal reflectance changes induced by transcorneal electrical stimulation in cat eyes.

    PubMed

    Morimoto, Takeshi; Kanda, Hiroyuki; Miyoshi, Tomomitsu; Hirohara, Yoko; Mihashi, Toshifumi; Kitaguchi, Yoshiyuki; Nishida, Kohji; Fujikado, Takashi

    2014-01-01

    Transcorneal electrical stimulation (TES) activates retinal neurons leading to visual sensations. How the retinal cells are activated by TES has not been definitively determined. Investigating the reflectance changes of the retina is an established technique and has been used to determine the mechanism of retinal activation. The purpose of this study was to evaluate the reflectance changes elicited by TES in cat eyes. Eight eyes of Eight cats were studied under general anesthesia. Biphasic electrical pulses were delivered transcornealy. The fundus images observed with near-infrared light (800-880 nm) were recorded every 25 ms for 26 s. To improve the signal-to-noise ratio, the images of 10 consecutive recordings were averaged. Two-dimensional topographic maps of the reflective changes were constructed by subtracting images before from those after the TES. The effects of different stimulus parameters, e.g., current intensity, pulse duration, frequency, and stimulus duration, on the reflective changes were studied. Our results showed that after TES, the reflective changes appeared on the retinal vessels and optic disc. The intensity of reflectance changes increased as the current intensity, pulse duration, and stimulation duration increased (P<0.05 for all). The maximum intensity of the reflective change was obtained when the stimulus frequency was 20 Hz. The time course of the reflectance changes was also altered by the stimulation parameters. The response started earlier and returned to the baseline later with higher current intensities, longer pulse durations, but the time of the peak of the response was not changed. These results showed that the reflective changes were due to the activation of retinal neurons by TES and might involve the vascular changes induced by an activation of the retinal neurons.

  7. Monte Carlo methods for localization of cones given multielectrode retinal ganglion cell recordings.

    PubMed

    Sadeghi, K; Gauthier, J L; Field, G D; Greschner, M; Agne, M; Chichilnisky, E J; Paninski, L

    2013-01-01

    It has recently become possible to identify cone photoreceptors in primate retina from multi-electrode recordings of ganglion cell spiking driven by visual stimuli of sufficiently high spatial resolution. In this paper we present a statistical approach to the problem of identifying the number, locations, and color types of the cones observed in this type of experiment. We develop an adaptive Markov Chain Monte Carlo (MCMC) method that explores the space of cone configurations, using a Linear-Nonlinear-Poisson (LNP) encoding model of ganglion cell spiking output, while analytically integrating out the functional weights between cones and ganglion cells. This method provides information about our posterior certainty about the inferred cone properties, and additionally leads to improvements in both the speed and quality of the inferred cone maps, compared to earlier "greedy" computational approaches.

  8. The neurotoxic effect of monosodium glutamate (MSG) on the retinal ganglion cells of the albino rat.

    PubMed

    van Rijn, C M; Marani, E; Rietveld, W J

    1986-07-01

    Monosodium glutamate (MSG) administered postnatally to the albino rat causes extensive destruction of the retina. This MSG effect does not result in complete blindness. Ganglion cells surviving the MSG treatment are healthy and functional. Using retrogradely transported HRP and Nissl staining in whole mounted retinas, it was found that the ganglion cells left after MSG treatment are not smaller than those in controls, that these cells do not belong to one cell size group, and that no cells size group is selectively missed. The results explain why photic entrainment of MSG treated animals is still possible.

  9. Eye drop delivery of pigment epithelium-derived factor-34 promotes retinal ganglion cell neuroprotection and axon regeneration.

    PubMed

    Vigneswara, Vasanthy; Esmaeili, Maryam; Deer, Louise; Berry, Martin; Logan, Ann; Ahmed, Zubair

    2015-09-01

    Axotomised retinal ganglion cells (RGCs) die rapidly by apoptosis and fail to regenerate because of the limited availability of neurotrophic factors and a lack of axogenic stimuli. However, we have recently showed that pigment epithelium-derived factor (PEDF) promotes RGC survival and axon regeneration after optic nerve crush injury. PEDF has multiple fragments of the native peptide that are neuroprotective, anti-angiogenic and anti-inflammatory. Here we investigated the neuroprotective and axogenic properties of a fragment of PEDF, PEDF-34, in retinal neurons in vitro and when delivered by intravitreal injection and eye drops in vivo. We found that PEDF-34 was 43% more neuroprotective and 52% more neuritogenic than PEDF-44 in vitro. Moreover, in vivo, intravitreal delivery of 1.88nM PEDF-34 was 71% RGC neuroprotective at 21days after optic nerve crush compared to intact controls, whilst daily eye drops containing 1.88nM PEDF-34 promoted 87% RGC survival. After topical eye drop delivery, PEDF-34 was detected in the vitreous body within 30min and attained physiologically relevant concentrations in the retina by 4h peaking at 1.4±0.05nM by 14days. In eye drop- compared to intravitreal-treated PEDF-34 animals, 55% more RGC axons regenerated 250μm beyond the optic nerve lesion. We conclude that daily topical eye drop application of PEDF-34 is superior to weekly intravitreal injections in promoting RGC survival and axon regeneration through both direct effects on retinal neurons and indirect effects on other retinal cells. Copyright © 2015. Published by Elsevier Inc.

  10. Rodent Anterior Ischemic Optic Neuropathy (rAION) Induces Regional Retinal Ganglion Cell Apoptosis with a Unique Temporal Pattern

    PubMed Central

    Slater, Bernard J.; Mehrabian, Zara; Guo, Yan; Hunter, Allan

    2009-01-01

    Purpose Nonarteritic anterior ischemic optic neuropathy (NAION) results in optic nerve damage with retinal ganglion cell (RGC) loss. An NAION model, rodent anterior ischemic optic neuropathy (rAION), was used to determine AION-associated mechanisms of RGC death and associated regional retinal changes. Methods rAION was induced in male Wistar rats, and the retinas analyzed at various times after induction. RGCs were positively identified by both retrograde fluorogold labeling and brain-expressed X-linked protein-1/2 (Bex1/2) immunoreactivity. RGC death was analyzed by fluorescein-tagged annexin-V labeling (FITC-annexin-V), as well as by terminal nucleotide nick-end labeling (TUNEL). Retinal flatmount preparations enabled regional retinal analysis of labeled dying cells. Apoptosis pathway activation was confirmed by Western analysis, with an antibody that recognizes cleaved caspase-3. Results Post-rAION, RGCs die by apoptosis over a longer period than previously recognized. Cleaved caspase-3 immunoreactivity was greatest between 11 and 15 days. rAION-induced RGC death occurs regionally, with sparing of large contiguous regions of RGCs. Conclusions rAION results in later RGC death than in traumatic optic nerve damage models. Apoptosis, measured by FITC-annexin, occurs maximally in the second to third week after infarct. Cleaved caspase-3 activation confirms that after rAION, RGCs undergo apoptosis by the caspase activation pathway. The regional pattern in dying RGCs after rAION implies that a measure of retinotopic organization occurs in the rodent optic nerve. The prolonged period from insult to death suggests that the window for successful treatment after ON infarct may be longer than previously recognized. PMID:18660428

  11. Spatially restricted electrical activation of retinal ganglion cells in the rabbit retina by hexapolar electrode return configuration

    NASA Astrophysics Data System (ADS)

    Habib, Amgad G.; Cameron, Morven A.; Suaning, Gregg J.; Lovell, Nigel H.; Morley, John W.

    2013-06-01

    Objective. Visual prostheses currently in development aim to restore some form of vision to patients suffering from diseases such as age-related macular degeneration and retinitis pigmentosa. Most rely on electrically stimulating inner retinal cells via electrodes implanted on or near the retina, resulting in percepts of light termed ‘phosphenes’. Activation of spatially distinct populations of cells in the retina is key for pattern vision to be produced. To achieve this, the electrical stimulation must be localized, activating cells only in the direct vicinity of the stimulating electrode(s). With this goal in mind, a hexagonal return (hexapolar) configuration has been proposed as an alternative to the traditional monopolar or bipolar return configurations for electrically stimulating the retina. This study investigated the efficacy of the hexapolar configuration in localizing the activation of retinal ganglion cells (RGCs), compared to a monopolar configuration. Approach. Patch-clamp electrophysiology was used to measure the activation thresholds of RGCs in whole-mount rabbit retina to monopolar and hexapolar electrical stimulation, applied subretinally. Main results. Hexapolar activation thresholds for RGCs located outside the hex guard were found to be significantly (>2 fold) higher than those located inside the area of tissue bounded by the hex guard. The hexapolar configuration localized the activation of RGCs more effectively than its monopolar counterpart. Furthermore, no difference in hexapolar thresholds or localization was observed when using cathodic-first versus anodic-first stimulation. Significance. The hexapolar configuration may provide an improved method for electrically stimulating spatially distinct populations of cells in retinal tissue.

  12. Complementation analysis of pseudorabies virus gE and gI mutants in retinal ganglion cell neurotropism.

    PubMed Central

    Enquist, L W; Dubin, J; Whealy, M E; Card, J P

    1994-01-01

    Pseudorabies virus glycoproteins gE and gI are required to infect some, but not all, regions of the rodent central nervous system after peripheral injection. After infection of the retina, pseudorabies virus mutants lacking either gE or gI can subsequently infect neural centers involved in the control of circadian function but cannot infect visual circuits mediating visual perception or the reflex movement of the eyes. In this study, we used genetic complementation to test the hypothesis that gE and gI are required for entry into the specific retinal ganglion cells that project to visual centers. These data strongly suggest that gE and gI must function after the viruses enter primary neurons in the retina. Images PMID:8035525

  13. Shp-2 regulates the TrkB receptor activity in the retinal ganglion cells under glaucomatous stress.

    PubMed

    Gupta, Vivek K; You, Yuyi; Klistorner, Alexander; Graham, Stuart L

    2012-11-01

    Tropomyosin-receptor-kinase B (TrkB receptor) activation plays an important role in the survival of retinal ganglion cells (RGCs). This study reports a novel finding that, SH2 domain-containing phosphatase-2 (Shp-2) binds to the TrkB receptor in RGCs and negatively regulates its activity under glaucomatous stress. This enhanced binding of TrkB and Shp2 is mediated through caveolin. Caveolin 1 and 3 undergo hyper-phosphorylation in RGCs under stress and bind to the Shp2 phosphatase. Shp2 undergoes activation under glaucomatous stress conditions in RGCs in vivo with a concurrent loss of TrkB activity. Inhibiting the Shp2 phosphatase restored TrkB activity in cells exposed to excitotoxic and oxidative stress. Collectively, these findings implicate a molecular basis of Shp2 mediated TrkB deactivation leading to RGC degeneration observed in glaucoma. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Differential effects of charybdotoxin on the activity of retinal ganglion cells in the dark- and light-adapted mouse retina

    PubMed Central

    Nemargut, Joseph P.; Zhu, Junling; Savoie, Brian T.; Wang, Guo-Yong

    2009-01-01

    Patch-clamp recordings were made from retinal ganglion cells in the mouse retina. Under dark adaptation, blockage of BKCa channels increases the spontaneous excitatory postsynaptic currents (EPSCs) and light-evoked On-EPSCs, while it decreases the light-evoked Off inhibitory postsynaptic currents (IPSCs). However, under light adaptation it decreases the light-evoked On-EPSCs, the spontaneous IPSCs and the light-evoked On- and Off-IPSCs. Blockage of BKCa channels significantly altered the outputs of RGCs by changing their light-evoked responses into a bursting pattern and increasing the light-evoked depolarization of the membrane potentials, while it did not significantly change the peak firing rates of light-evoked responses. PMID:19084033

  15. Classification of nAChRβ2-immunoreactive retinal ganglion cells and their tectal projections in chicks.

    PubMed

    Naito, Jumpei; Tanada, Yukiko; Watanabe, Takumi

    2013-12-01

    The relationship between the type of retinal ganglion cell (RGC) and the retinoreceptive layer of the tectum is investigated by the immunostaining of RGCs with nicotinic acetylcholine receptorβ2 (nAChRβ2) antibody and intracellular staining by DiI and also by anterograde degeneration and biotinylated dextran amine labeling of retinotectal fibers in chicks. The results strongly suggest that many of the RGCs that express immunoreactivity to nAChRβ2 send axons to tectal layer 7 and are mainly classified into the simple-type of Groups II and III, which contain the cells providing middle-sized to large dendritic fields with simple dendritic arborization. These nAChRβ2-immunoreactive RGCs receive visual information via the multiple sublayers of the inner plexiform layer.

  16. Electrical synaptic input to ganglion cells underlies differences in the output and absolute sensitivity of parallel retinal circuits.

    PubMed

    Murphy, Gabe J; Rieke, Fred

    2011-08-24

    Parallel circuits throughout the CNS exhibit distinct sensitivities and responses to sensory stimuli. Ambiguities in the source and properties of signals elicited by physiological stimuli, however, frequently obscure the mechanisms underlying these distinctions. We found that differences in the degree to which activity in two classes of Off retinal ganglion cell (RGC) encode information about light stimuli near detection threshold were not due to obvious differences in the cells' intrinsic properties or the chemical synaptic input the cells received; indeed, differences in the cells' light responses were largely insensitive to block of fast ionotropic glutamate receptors. Instead, the distinct responses of the two types of RGCs likely reflect differences in light-evoked electrical synaptic input. These results highlight a surprising strategy by which the retina differentially processes and routes visual information and provide new insight into the circuits that underlie responses to stimuli near detection threshold.

  17. Palmitic acid triggers cell apoptosis in RGC-5 retinal ganglion cells through the Akt/FoxO1 signaling pathway.

    PubMed

    Yan, Panshi; Tang, Shu; Zhang, Haifeng; Guo, Yuanyuan; Zeng, Zhiwen; Wen, Qiang

    2017-04-01

    Hallmarks of the pathophysiology of glaucoma are oxidative stress and apoptotic death of retinal ganglion cells (RGCs). Lipotoxicity, involving a series of pathological cellular responses after exposure to elevated levels of fatty acids, leads to oxidative stress and cell death in various cell types. The phosphatidylinositol-3-kinase/protein kinase B/Forkhead box O1 (PI3K/Akt/FoxO1) pathway is crucial for cell survival and apoptosis. More importantly, FoxO1 gene has been reported to confer relatively higher risks for eye diseases including glaucoma. However, little information is available regarding the interaction between FoxO1 and RGC apoptosis, much less a precise mechanism. In the present study, immortalized rat retinal ganglion cell line 5 (RGC-5) was used as a model to study the toxicity of palmitic acid (PA), as well as underlying mechanisms. We found that PA exposure significantly decreased cell viability by enhancing apoptosis in RGC-5 cells, as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. PA also induced a remarkable increase in reactive oxygen species and malondialdehyde. Moreover, PA significantly decreased the level of phospho-Akt and phospho-FoxO1 in cells. Finally, shRNA knockdown and plasmid overexpression studies displayed that downregulation of Akt protein or upregulation of FoxO1 protein augmented cell death, while knockdown of FoxO1 or overexpression of Akt1 abolished PA-induced cell death. Collectively, our results indicated that PA-induced cell death is mediated through modulation of Akt/FoxO1 pathway activity.

  18. Transient Expression of Fez Family Zinc Finger 2 Protein Regulates the Brn3b Gene in Developing Retinal Ganglion Cells.

    PubMed

    Qu, Chunsheng; Bian, Dandan; Li, Xue; Xiao, Jian; Wu, Chunping; Li, Yue; Jiang, Tian; Zhou, Xiangtian; Qu, Jia; Chen, Jie-Guang

    2016-04-01

    Retinal ganglion cells (RGCs) are projection neurons in the neural retina that relay visual information from the environment to the central nervous system. The early expression of MATH5 endows the post-mitotic precursors with RGC competence and leads to the activation ofBrn3bthat marks committed RGCs. Nevertheless, this fate commitment process and, specifically, regulation ofBrn3bremain elusive. To explore the molecular mechanisms underlying RGC generation in the mouse retina, we analyzed the expression and function of Fez family zinc finger 2 (FEZF2), a transcription factor critical for the development of projection neurons in the cerebral cortex.Fezf2mRNA and protein were transiently expressed at embryonic day 16.5 in the inner neuroblast layer and the prospective ganglion cell layer of the retina, respectively. Knockout ofFezf2in the developing retina reduced BRN3B+ cells and increased apoptotic cell markers.Fezf2knockdown by retinalin uteroelectroporation diminished BRN3B but not the coexpressed ISLET1 and BRN3A, indicating that the BRN3B decrease was the cause, not the result, of the overall reduction of BRN3B+ RGCs in theFezf2knockout retina. Moreover, the mRNA and promoter activity ofBrn3bwere increasedin vitroby FEZF2, which bound to a 5' regulatory fragment in theBrn3bgenomic locus. These results indicate that transient expression ofFezf2in the retina modulates the transcription ofBrn3band the survival of RGCs. This study improves our understanding of the transcriptional cascade required for the specification of RGCs and provides novel insights into the molecular basis of retinal development.

  19. Corticothalamic Axons Are Essential for Retinal Ganglion Cell Axon Targeting to the Mouse Dorsal Lateral Geniculate Nucleus

    PubMed Central

    Shanks, James A.; Ito, Shinya; Schaevitz, Laura; Yamada, Jena; Chen, Bin; Litke, Alan

    2016-01-01

    Retinal ganglion cells (RGCs) relay information about the outside world to multiple subcortical targets within the brain. This information is either used to dictate reflexive behaviors or relayed to the visual cortex for further processing. Many subcortical visual nuclei also receive descending inputs from projection neurons in the visual cortex. Most areas receive inputs from layer 5 cortical neurons in the visual cortex but one exception is the dorsal lateral geniculate nucleus (dLGN), which receives layer 6 inputs and is also the only RGC target that sends direct projections to the cortex. Here we ask how visual system development and function changes in mice that develop without a cortex. We find that the development of a cortex is essential for RGC axons to terminate in the dLGN, but is not required for targeting RGC axons to other subcortical nuclei. RGC axons also fail to target to the dLGN in mice that specifically lack cortical layer 6 projections to the dLGN. Finally, we show that when mice develop without a cortex they can still perform a number of vision-dependent tasks. SIGNIFICANCE STATEMENT The dorsal lateral geniculate nucleus (dLGN) is a sensory thalamic relay area that receives feedforward inputs from retinal ganglion cells (RGCs) in the retina, and feed back inputs from layer 6 neurons in the visual cortex. In this study we examined genetically manipulated mice that develop without a cortex or without cortical layer 6 axonal projections, and find that RGC axons fail to project to the dLGN. Other RGC recipient areas, such as the superior colliculus and suprachiasmatic nucleus, are targeted normally. These results provide support for a new mechanism of target selection that may be specific to the thalamus, whereby descending cortical axons provide an activity that promotes feedforward targeting of RGC axons to the dLGN. PMID:27170123