Science.gov

Sample records for acoustic ganglion cells

  1. Acoustical stimulus changes the expression of stromal cell-derived factor-1 in the spiral ganglion neurons of the rat cochlea.

    PubMed

    Zhang, Peng-zhi; Cao, Xin-sheng; Jiang, Xing-wang; Wang, Jie; Liang, Peng-fei; Wang, Shu-juan; Mi, Wen-juan; Chen, Fu-quan; Chen, Yang; Xue, Tao; Chen, Jun; Qiu, Jian-hua

    2014-02-21

    Neural stem cell (NSC) transplantation into the cochlea has been tested as a treatment for spiral ganglion neuron (SGN) degenerative disease and injury in various animal models. A recent study has shown evidence of functional recovery after transplantation of the stem cells into a degenerated-SGN model. Chemokine stromal cell-derived factor-1 (SDF-1, or known as CXC chemokine ligand-12, CXCL-12) signaling through CXCR4 has previously been identified as a key step in the homing of the stem cells within the injury areas; meanwhile, studies have revealed that the SDF-1/CXCR4 axis is also involved in axon guidance and pathfinding. A study found that transplanted neural precursor cells can migrate to the root of the auditory nerve when animals are subjected to an augmented acoustic environment (AAE). In accordance with these studies, we hypothesize that AAE will up-regulate the expression of SDF-1 in acoustic nerves. We tested our hypothesis by examining the expression of SDF-1 in different acoustic environments, and the results were confirmed by the auditory brainstem response (ABR), immunohistochemical and RT-PCR analyses. The results showed that SDF-1 was expressed at a relatively low level in the SGNs under normal animal unit acoustic conditions (40-50 dB). Moreover, it was significantly up-regulated in the SGNs under the 75 dB (augmented physiological process without hearing loss) and 90 dB AAE (pathological process with light hearing loss) conditions; however, under the 115 dB AAE (pathological process with severe hearing loss) condition, the expression of SDF-1 was not up-regulated. The results confirmed that appropriately augmented acoustical stimuli lead to the up-regulation of SDF-1, which may assist in the migration of the transplanted cells and the subsequent establishment of essential synaptic contacts between the exogenous cells and the host auditory pathway. PMID:24394908

  2. Stem Cells, Retinal Ganglion Cells, and Glaucoma

    PubMed Central

    Sluch, Valentin M.; Zack, Donald J.

    2015-01-01

    Retinal ganglion cells represent an essential neuronal cell type for vision. These cells receive inputs from light-sensing photoreceptors via retinal interneurons and then relay these signals to the brain for further processing. Retinal ganglion cell diseases that result in cell death, e.g. glaucoma, often lead to permanent damage since mammalian nerves do not regenerate. Stem cell differentiation can generate cells needed for replacement or can be used to generate cells capable of secreting protective factors to promote survival. In addition, stem cell-derived cells can be used in drug screening research. Here, we discuss the current state of stem cell research potential for interference in glaucoma and other optic nerve diseases with a focus on stem cell differentiation to retinal ganglion cells. PMID:24732765

  3. 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. PMID:20959623

  4. Molecular biology of retinal ganglion cells.

    PubMed Central

    Xiang, M; Zhou, H; Nathans, J

    1996-01-01

    Retinal ganglion cells are the output neurons that encode and transmit information from the eye to the brain. Their diverse physiologic and anatomic properties have been intensively studied and appear to account well for a number of psychophysical phenomena such as lateral inhibition and chromatic opponency. In this paper, we summarize our current view of retinal ganglion cell properties and pose a number of questions regarding underlying molecular mechanisms. As an example of one approach to understanding molecular mechanisms, we describe recent work on several POU domain transcription factors that are expressed in subsets of retinal ganglion cells and that appear to be involved in ganglion cell development. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:8570601

  5. Changes in ganglion cells during retinal degeneration.

    PubMed

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

    2016-08-01

    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. PMID:27132232

  6. Evaluation of the percentage of ganglion cells in the ganglion cell layer of the rodent retina

    PubMed Central

    Schlamp, Cassandra L.; Montgomery, Angela D.; Mac Nair, Caitlin E.; Schuart, Claudia; Willmer, Daniel J.

    2013-01-01

    Purpose Retinal ganglion cells comprise a percentage of the neurons actually residing in the ganglion cell layer (GCL) of the rodent retina. This estimate is useful to extrapolate ganglion cell loss in models of optic nerve disease, but the values reported in the literature are highly variable depending on the methods used to obtain them. Methods We tested three retrograde labeling methods and two immunostaining methods to calculate ganglion cell number in the mouse retina (C57BL/6). Additionally, a double-stain retrograde staining method was used to label rats (Long-Evans). The number of total neurons was estimated using a nuclear stain and selecting for nuclei that met specific criteria. Cholinergic amacrine cells were identified using transgenic mice expressing Tomato fluorescent protein. Total neurons and total ganglion cell numbers were measured in microscopic fields of 104 µm2 to determine the percentage of neurons comprising ganglion cells in each field. Results Historical estimates of the percentage of ganglion cells in the mouse GCL range from 36.1% to 67.5% depending on the method used. Experimentally, retrograde labeling methods yielded a combined estimate of 50.3% in mice. A retrograde method also yielded a value of 50.21% for rat retinas. Immunolabeling estimates were higher at 64.8%. Immunolabeling may introduce overestimates, however, with non-specific labeling effects, or ectopic expression of antigens in neurons other than ganglion cells. Conclusions Since immunolabeling methods may overestimate ganglion cell numbers, we conclude that 50%, which is consistently derived from retrograde labeling methods, is a reliable estimate of the ganglion cells in the neuronal population of the GCL. PMID:23825918

  7. Stratification of alpha ganglion cells and ON/OFF directionally selective ganglion cells in the rabbit retina

    PubMed Central

    ZHANG, JIAN; LI, WEI; HOSHI, HIDEO; MILLS, STEPHEN L.; MASSEY, STEPHEN C.

    2007-01-01

    The correlation between cholinergic sensitivity and the level of stratification for ganglion cells was examined in the rabbit retina. As examples, we have used ON or OFF α ganglion cells and ON/OFF directionally selective (DS) ganglion cells. Nicotine, a cholinergic agonist, depolarized ON/OFF DS ganglion cells and greatly enhanced their firing rates but it had modest excitatory effects on ON or OFF α ganglion cells. As previously reported, we conclude that DS ganglion cells are the most sensitive to cholinergic drugs. Confocal imaging showed that ON/OFF DS ganglion cells ramify precisely at the level of the cholinergic amacrine cell dendrites, and co-fasciculate with the cholinergic matrix of starburst amacrine cells. However, neither ON or OFF α ganglion cells have more than a chance association with the cholinergic matrix. Z-axis reconstruction showed that OFF α ganglion cells stratify just below the cholinergic band in sublamina a while ON α ganglion cells stratify just below cholinergic b. The latter is at the same level as the terminals of calbindin bipolar cells. Thus, the calbindin bipolar cell appears to be a prime candidate to provide the bipolar cell input to ON α ganglion cells in the rabbit retina. We conclude that the precise level of stratification is correlated with the strength of cholinergic input. Alpha ganglion cells receive a weak cholinergic input and they are narrowly stratified just below the cholinergic bands. PMID:16212709

  8. Learning LM Specificity for Ganglion Cells

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J.

    2015-01-01

    Unsupervised learning models have been proposed based on experience (Ahumada and Mulligan, 1990;Wachtler, Doi, Lee and Sejnowski, 2007) that allow the cortex to develop units with LM specific color opponent receptive fields like the blob cells reported by Hubel and Wiesel on the basis of visual experience. These models used ganglion cells with LM indiscriminate wiring as inputs to the learning mechanism, which was presumed to occur at the cortical level.

  9. 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.

  10. Neuronal cell lines as model dorsal root ganglion neurons

    PubMed Central

    Yin, Kathleen; Baillie, Gregory J

    2016-01-01

    Background Dorsal root ganglion neuron-derived immortal cell lines including ND7/23 and F-11 cells have been used extensively as in vitro model systems of native peripheral sensory neurons. However, while it is clear that some sensory neuron-specific receptors and ion channels are present in these cell lines, a systematic comparison of the molecular targets expressed by these cell lines with those expressed in intact peripheral neurons is lacking. Results In this study, we examined the expression of RNA transcripts in the human neuroblastoma-derived cell line, SH-SY5Y, and two dorsal root ganglion hybridoma cell lines, F-11 and ND7/23, using Illumina next-generation sequencing, and compared the results with native whole murine dorsal root ganglions. The gene expression profiles of these three cell lines did not resemble any specific defined dorsal root ganglion subclass. The cell lines lacked many markers for nociceptive sensory neurons, such as the Transient receptor potential V1 gene, but expressed markers for both myelinated and unmyelinated neurons. Global gene ontology analysis on whole dorsal root ganglions and cell lines showed similar enrichment of biological process terms across all samples. Conclusions This paper provides insights into the receptor repertoire expressed in common dorsal root ganglion neuron-derived cell lines compared with whole murine dorsal root ganglions, and illustrates the limits and potentials of these cell lines as tools for neuropharmacological exploration. PMID:27130590

  11. Selectivity for multiple stimulus features in retinal ganglion cells.

    PubMed

    Fairhall, Adrienne L; Burlingame, C Andrew; Narasimhan, Ramesh; Harris, Robert A; Puchalla, Jason L; Berry, Michael J

    2006-11-01

    Under normal viewing conditions, retinal ganglion cells transmit to the brain an encoded version of the visual world. The retina parcels the visual scene into an array of spatiotemporal features, and each ganglion cell conveys information about a small set of these features. We study the temporal features represented by salamander retinal ganglion cells by stimulating with dynamic spatially uniform flicker and recording responses using a multi-electrode array. While standard reverse correlation methods determine a single stimulus feature--the spike-triggered average--multiple features can be relevant to spike generation. We apply covariance analysis to determine the set of features to which each ganglion cell is sensitive. Using this approach, we found that salamander ganglion cells represent a rich vocabulary of different features of a temporally modulated visual stimulus. Individual ganglion cells were sensitive to at least two and sometimes as many as six features in the stimulus. While a fraction of the cells can be described by a filter-and-fire cascade model, many cells have feature selectivity that has not previously been reported. These reverse models were able to account for 80-100% of the information encoded by ganglion cells. PMID:16914609

  12. Degeneration and regeneration of ganglion cell axons.

    PubMed

    Weise, J; Ankerhold, R; Bähr, M

    2000-01-15

    The retino-tectal system has been used to study developmental aspects of axon growth, synapse formation and the establishment of a precise topographic order as well as degeneration and regeneration of adult retinal ganglion cell (RGC) axons after axonal lesion. This paper reviews some novel findings that provide new insights into the mechanisms of developmental RGC axon growth, pathfinding, and target formation. It also focuses on the cellular and molecular cascades that underlie RGC degeneration following an axonal lesion and on some therapeutic strategies to enhance survival of axotomized RGCs in vivo. In addition, this review deals with problems related to the induction of regeneration after axonal lesion in the adult CNS using the retino-tectal system as model. Different therapeutic approaches to promote RGC regeneration and requirements for specific target formation of regenerating RGCs in vitro and in vivo are discussed. PMID:10649506

  13. Frequency Responses of Rat Retinal Ganglion Cells

    PubMed Central

    Cloherty, Shaun L.; Hung, Yu-Shan; Kameneva, Tatiana; Ibbotson, Michael R.

    2016-01-01

    There are 15–20 different types of retinal ganglion cells (RGC) in the mammalian retina, each encoding different aspects of the visual scene. The mechanism by which post-synaptic signals from the retinal network generate spikes is determined by each cell’s intrinsic electrical properties. Here we investigate the frequency responses of morphologically identified rat RGCs using intracellular injection of sinusoidal current waveforms, to assess their intrinsic capabilities with minimal contributions from the retinal network. Recorded cells were classified according to their morphological characteristics (A, B, C or D-type) and their stratification (inner (i), outer (o) or bistratified) in the inner plexiform layer (IPL). Most cell types had low- or band-pass frequency responses. A2, C1 and C4o cells were band-pass with peaks of 15–30 Hz and low-pass cutoffs above 56 Hz (A2 cells) and ~42 Hz (C1 and C4o cells). A1 and C2i/o cells were low-pass with peaks of 10–15 Hz (cutoffs 19–25 Hz). Bistratified D1 and D2 cells were also low-pass with peaks of 5–10 Hz (cutoffs ~16 Hz). The least responsive cells were the B2 and C3 types (peaks: 2–5 Hz, cutoffs: 8–11 Hz). We found no difference between cells stratifying in the inner and outer IPL (i.e., ON and OFF cells) or between cells with large and small somas or dendritic fields. Intrinsic physiological properties (input resistance, spike width and sag) had little impact on frequency response at low frequencies, but account for 30–40% of response variability at frequencies >30 Hz. PMID:27341669

  14. 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

  15. 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. PMID:26427477

  16. 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

  17. 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.

  18. 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

  19. T-cell-mediated ganglionitis associated with acute sensory neuronopathy.

    PubMed

    Hainfellner, J A; Kristoferitsch, W; Lassmann, H; Bernheimer, H; Neisser, A; Drlicek, M; Beer, F; Budka, H

    1996-04-01

    A 67-year-old man presented with acute painful sensory loss, areflexia, ataxia, urinary retention, and severe constipation and became unable to walk within 2 weeks. He died suddenly 5 weeks after the onset of symptoms. Autopsy revealed widespread inflammation of sensory and autonomic ganglia with immunocytochemical evidence of a CD8+ T cell-mediated cytotoxic attack against ganglion neurons. This observation suggests a novel pathogenetic mechanism of immune-mediated human ganglion cell damage comparable to mechanisms operating in polymyositis.

  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. 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. PMID:26526333

  2. 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

  3. Retinal Ganglion Cell Adaptation to Small Luminance Fluctuations

    PubMed Central

    Freeman, Daniel K.; Graña, Gilberto

    2010-01-01

    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. PMID:20538771

  4. 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.

  5. Cell type-specific bipolar cell input to ganglion cells in the mouse retina.

    PubMed

    Neumann, S; Hüser, L; Ondreka, K; Auler, N; Haverkamp, S

    2016-03-01

    Many distinct ganglion cell types, which are the output elements of the retina, were found to encode for specific features of a visual scene such as contrast, color information or movement. The detailed composition of retinal circuits leading to this tuning of retinal ganglion cells, however, is apart from some prominent examples, largely unknown. Here we aimed to investigate if ganglion cell types in the mouse retina receive selective input from specific bipolar cell types or if they sample their synaptic input non-selectively from all bipolar cell types stratifying within their dendritic tree. To address this question we took an anatomical approach and immunolabeled retinae of two transgenic mouse lines (GFP-O and JAM-B) with markers for ribbon synapses and type 2 bipolar cells. We morphologically identified all green fluorescent protein (GFP)-expressing ganglion cell types, which co-stratified with type 2 bipolar cells and assessed the total number of bipolar input synapses and the proportion of synapses deriving from type 2 bipolar cells. Only JAM-B ganglion cells received synaptic input preferentially from bipolar cell types other than type 2 bipolar cells whereas the other analyzed ganglion cell types sampled their bipolar input most likely from all bipolar cell terminals within their dendritic arbor.

  6. Wide-field ganglion cells in macaque retinas

    PubMed Central

    YAMADA, ELIZABETH S.; BORDT, ANDREA S.; MARSHAK, DAVID W.

    2012-01-01

    To describe the wide-field ganglion cells, they were injected intracellularly with Neurobiotin using an in vitro preparation of macaque retina and labeled with streptavidin-Cy3. The retinas were then labeled with antibodies to choline acetyltransferase and other markers to indicate the depth of the dendrites within the inner plexiform layer (IPL) and analyzed by confocal microscopy. There were eight different subtypes of narrowly unistratified cells that ramified in each of the 5 strata, S1–5, including narrow thorny, large sparse, large moderate, large dense, large radiate, narrow wavy, large very sparse, and fine very sparse. There were four types of broadly stratified cells with dendritic trees extending from S4 to S2. One type resembled the parvocellular giant cell and another the broad thorny type described previously in primates. Another broadly stratified cell was called multi-tufted based on its distinctive dendritic branching pattern. The fourth type had been described previously, but not named; we called it broad wavy. There was a bistratified type with its major arbor in S5, the same level as the blue cone bipolar cell; it resembled the large, bistratified cell with blue ON-yellow OFF responses described recently. Two wide-field ganglion cell types were classified as diffuse because they had dendrites throughout the IPL. One had many small branches and was named thorny diffuse. The second was named smooth diffuse because it had straighter dendrites that lacked these processes. Dendrites of the large moderate and multi-tufted cells cofasciculated with ON-starburst cell dendrites and were, therefore, candidates to be ON- and ON–OFF direction-selective ganglion cells, respectively. We concluded that there are at least 15 morphoplogical types of wide-field ganglion cells in macaque retinas. PMID:16212697

  7. Characterization of a transformed rat retinal ganglion cell line.

    PubMed

    Krishnamoorthy, R R; Agarwal, P; Prasanna, G; Vopat, K; Lambert, W; Sheedlo, H J; Pang, I H; Shade, D; Wordinger, R J; Yorio, T; Clark, A F; Agarwal, N

    2001-01-31

    The purpose of the present study was to establish a rat retinal ganglion cell line by transformation of rat retinal cells. For this investigation, retinal cells were isolated from postnatal day 1 (PN1) rats and transformed with the psi2 E1A virus. In order to isolate retinal ganglion cells (RGC), single cell clones were chosen at random from the transformed cells. Expression of Thy-1 (a marker for RGC), glial fibrillary acidic protein (GFAP, a positive marker for Muller cells), HPC-1/syntaxin (a marker for amacrine cells), 8A1 (a marker for horizontal and ganglion cells) and neurotrophins was studied using reverse transcriptase-polymerase chain reaction (RT-PCR), immunoblotting and immunocytochemistry. One of the retinal cell clones, designated RGC-5, was positive for Thy-1, Brn-3C, Neuritin, NMDA receptor, GABA-B receptor, and synaptophysin expression and negative for GFAP, HPC-1, and 8A1, suggesting that it represented a putative RGC clone. The results of RT-PCR analysis were confirmed by immunocytochemistry for Thy-1 and GFAP. Upon further characterization by immunoblotting, the RGC-5 clone was positive for Thy-1, negative for GFAP, 8A1 and syntaxin. RGC 5 cells were also positive for the expression of neurotrophins and their cognate receptors. To establish the physiological relevance of RGC-5, the effects of serum/trophic factor deprivation and glutamate toxicity were analyzed to determine if these cells would undergo apoptosis. The protective effects of neurotrophins on RGC-5 after serum deprivation was also investigated. Apoptosis was studied by terminal deoxynucleotidyl transferase-mediated fluoresceinated dUTP nick end labeling (TUNEL). Serum deprivation resulted in apoptosis and supplementation with both BDNF and NT-4 in the growth media, protected the RGC-5 cells from undergoing apoptosis. On differentiation with succinyl concanavalin A (sConA), RGC-5 cells became sensitive to glutamate toxicity, which could be reversed by inclusion of ciplizone (MK801

  8. Colocalization of HCN Channel Subunits in Rat Retinal Ganglion Cells

    PubMed Central

    Stradleigh, Tyler W.; Ogata, Genki; Partida, Gloria J.; Oi, Hanako; Greenberg, Kenneth P.; Krempely, Kalen S.; Ishida, Andrew T.

    2011-01-01

    The current-passing pore of mammalian hyperpolarization-activated, cyclic nucleotide-gated ("HCN") channels is formed by subunit isoforms denoted HCN1-4. In various brain areas, antibodies directed against multiple isoforms bind to single neurons and the current ("Ih") passed during hyperpolarizations differs from that of heterologously expressed homomeric channels. By contrast, retinal rod, cone, and bipolar cells appear to use homomeric HCN channels. Here, we assess the generality of this pattern by examining HCN1 and HCN4 immunoreactivity in rat retinal ganglion cells, measuring Ih in dissociated cells, and testing whether HCN1 and HCN4 protein coimmunoprecipitate. Nearly half of the ganglion cells in whole-mounted retinae bound antibodies against both isoforms. Consistent with colocalization and physical association, 8-bromo-cAMP shifted the voltage-sensitivity of Ih less than that of HCN4 channels and more than that of HCN1 channels, and HCN1 coimmunoprecipitated with HCN4 from membrane fraction proteins. Lastly, the immunopositive somata ranged in diameter from the smallest to the largest in rat retina, the dendrites of immunopositive cells arborized at various levels of the inner plexiform layer and over fields of different diameters, and Ih activated with similar kinetics and proportions of fast and slow components in small, medium, and large somata. These results show that different HCN subunits colocalize in single retinal ganglion cells, identify a subunit that can reconcile native Ih properties with the previously reported presence of HCN4 in these cells, and indicate that Ih is biophysically similar in morphologically diverse retinal ganglion cells and differs from Ih in rods, cones, and bipolar cells. PMID:21456027

  9. Type II cochlear ganglion cells in the chinchilla.

    PubMed

    Ruggero, M A; Santi, P A; Rich, N C

    1982-12-01

    In order to ascertain whether Type II cochlear ganglion cells project to the brain, we have studied the retrograde transport of horseradish peroxidase (HRP) from the cochlear nucleus to the spiral ganglion of the chinchilla. In this animal there exist two types of ganglion neurons, which closely correspond to those previously described in guinea pigs, cats and rats. As in the guinea pig, the majority population (Type I) consists of relatively large, myelinated neurons. The minority population (Type II, 10% of the total population) consists of small, mostly unmyelinated cells, with filamentous cytoplasm and finely grained nuclear chromatin. Type II neurons tend to be clustered toward the peripheral side of Rosenthal's canal, often in close proximity to the intraganglionic spiral bundle. By 24 h after injections of HRP into the cochlear nucleus, incubation of the cochlear ganglion in diaminobenzidine/H2O2 reveals abundant HRP label in both Type I and Type II neurons. Type II neurons, however, tend to be labelled less intensely than Type I neurons. Control experiments, consisting of spillage of HRP solution over the cochlear nucleus, were carried out to determine how much HRP might be picked up by neurons after HRP diffusion. Comparison of cochleae from injected animals and from the control animals suggests that most of the label that was found in ganglion neurons after cochlear nucleus injections represents axonally transported HRP. We conclude, at least tentatively, that Type II neurons project to the brain. The fact that less label is found in Type II neurons that in Type I neurons suggests that the former have thinner axons and/or finer terminals in the cochlear nucleus. PMID:6185462

  10. 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. PMID:26735013

  11. 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.

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

    PubMed

    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

  13. 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

  14. White Matter Consequences of Retinal Receptor and Ganglion Cell Damage

    PubMed Central

    Ogawa, Shumpei; Takemura, Hiromasa; Horiguchi, Hiroshi; Terao, Masahiko; Haji, Tomoki; Pestilli, Franco; Yeatman, Jason D.; Tsuneoka, Hiroshi; Wandell, Brian A.; Masuda, Yoichiro

    2014-01-01

    Purpose. Patients with Leber hereditary optic neuropathy (LHON) and cone-rod dystrophy (CRD) have central vision loss; but CRD damages the retinal photoreceptor layer, and LHON damages the retinal ganglion cell (RGC) layer. Using diffusion MRI, we measured how these two types of retinal damage affect the optic tract (ganglion cell axons) and optic radiation (geniculo-striate axons). Methods. Adult onset CRD (n = 5), LHON (n = 6), and healthy controls (n = 14) participated in the study. We used probabilistic fiber tractography to identify the optic tract and the optic radiation. We compared axial and radial diffusivity at many positions along the optic tract and the optic radiation. Results. In both types of patients, diffusion measures within the optic tract and the optic radiation differ from controls. The optic tract change is principally a decrease in axial diffusivity; the optic radiation change is principally an increase in radial diffusivity. Conclusions. Both photoreceptor layer (CRD) and retinal ganglion cell (LHON) retinal disease causes substantial change in the visual white matter. These changes can be measured using diffusion MRI. The diffusion changes measured in the optic tract and the optic radiation differ, suggesting that they are caused by different biological mechanisms. PMID:25257055

  15. Effects of metal ions on fibroblasts and spiral ganglion cells.

    PubMed

    Paasche, G; Ceschi, P; Löbler, M; Rösl, C; Gomes, P; Hahn, A; Rohm, H W; Sternberg, K; Lenarz, T; Schmitz, K-P; Barcikowski, S; Stöver, T

    2011-04-01

    Degeneration of spiral ganglion cells (SGC) after deafness and fibrous tissue growth around the electrode carrier after cochlear implantation are two of the major challenges in current cochlear implant research. Metal ions are known to possess antimicrobial and antiproliferative potential. The use of metal ions could therefore provide a way to reduce tissue growth around the electrode array after cochlear implantation. Here, we report on in vitro experiments with different concentrations of metal salts with antiproliferative and toxic effects on fibroblasts, PC-12 cells, and freshly isolated spiral ganglion cells, the target cells for electrical stimulation by a cochlear implant. Standard cell lines (NIH/3T3 and L-929 fibroblasts and PC-12 cells) and freshly isolated SGC were incubated with concentrations of metal ions between 0.3 μmol/liter and 10 mmol/liter for 48 hr. Cell survival was investigated by neutral red uptake, CellQuantiBlue assay, or counting of stained surviving neurons. Silver ions exhibited distinct thresholds for proliferating and confluent cells. For zinc ions, the effective concentration was lower for fibroblasts than for PC-12 cells. SGC showed comparable thresholds for reduced cell survival not only for silver and zinc ions but also for copper(II) ions, indicating that these ions might be promising for reducing tissue growth on the surface of CI electrode arrays. These effects were also observed when combinations of two of these ions were investigated. PMID:21312225

  16. Identification of cone mechanisms in monkey ganglion cells

    PubMed Central

    Gouras, Peter

    1968-01-01

    1. Blue, green, and red sensitive cone mechanisms have been studied in two types of on-centre ganglion cells in the Rhesus monkey's retina. 2. One type of cell receives signals from both green and red sensitive cone mechanisms, both of which excite in the centre and inhibit in the periphery of the cell's receptive field. These cells discharge transiently to maintained stimuli of any wave-length and are called phasic. 3. The second type of cell receives excitatory signals from only one cone mechanism, either blue, green or red sensitive, in the centre, and inhibition from another cone mechanism in the periphery of its receptive field. These cells discharge continuously to maintained stimuli of appropriate wave-length and are called tonic. 4. Tonic cells outnumber phasic cells although both are found adjacent to one another throughout the retina. Phasic cells are relatively more common toward the periphery and tonic cells relatively more common toward the fovea. PMID:4974745

  17. Tissue Engineering the Retinal Ganglion Cell Nerve Fiber Layer

    PubMed Central

    Kador, Karl E.; Montero, Ramon B.; Venugopalan, Praseeda; Hertz, Jonathan; Zindell, Allison N.; Valenzuela, Daniel A.; Uddin, Mohammed S.; Lavik, Erin B.; Muller, Kenneth J.; Andreopoulos, Fotios M.; Goldberg, Jeffrey L.

    2013-01-01

    Retinal degenerative diseases, such as glaucoma and macular degeneration, affect millions of people worldwide and ultimately lead to retinal cell death and blindness. Cell transplantation therapies for photoreceptors demonstrate integration and restoration of function, but transplantation into the ganglion cell layer is more complex, requiring guidance of axons from transplanted cells to the optic nerve head in order to reach targets in the brain. Here we create a biodegradable electrospun (ES) scaffold designed to direct the growth of retinal ganglion cell (RGC) axons radially, mimicking axon orientation in the retina. Using this scaffold we observed an increase in RGC survival and no significant change in their electrophysiological properties. When analyzed for alignment, 81% of RGCs were observed to project axons radially along the scaffold fibers, with no difference in alignment compared to the nerve fiber layer of retinal explants. When transplanted onto retinal explants, RGCs on ES scaffolds followed the radial pattern of the host retinal nerve fibers, whereas RGCs transplanted directly grew axons in a random pattern. Thus, the use of this scaffold as a cell delivery device represents a significant step towards the use of cell transplant therapies for the treatment of glaucoma and other retinal degenerative diseases. PMID:23489919

  18. Sympathetic and sensory innervation of small intensely fluorescent (SIF) cells in rat superior cervical ganglion.

    PubMed

    Takaki, Fumiya; Nakamuta, Nobuaki; Kusakabe, Tatsumi; Yamamoto, Yoshio

    2015-02-01

    The sympathetic ganglion contains small intensely fluorescent (SIF) cells derived from the neural crest. We morphologically characterize SIF cells and focus on their relationship with ganglionic cells, preganglionic nerve fibers and sensory nerve endings. SIF cells stained intensely for tyrosine hydroxylase (TH), with a few cells also being immunoreactive for dopamine β-hydroxylase (DBH). Vesicular acetylcholine transporter (VAChT)-immunoreactive puncta were distributed around some clusters of SIF cells, whereas some SIF cells closely abutted DBH-immunoreactive ganglionic cells. SIF cells contained bassoon-immunoreactive products beneath the cell membrane at the attachments and on opposite sites to the ganglionic cells. Ganglion neurons and SIF cells were immunoreactive to dopamine D2 receptors. Immunohistochemistry for P2X3 revealed ramified nerve endings with P2X3 immunoreactivity around SIF cells. Triple-labeling for P2X3, TH and VAChT allowed the classification of SIF cells into three types based on their innervation: (1) with only VAChT-immunoreactive puncta, (2) with only P2X3-immunoreactive nerve endings, (3) with both P2X3-immunoreactive nerve endings and VAChT-immunoreactive puncta. The results of retrograde tracing with fast blue dye indicated that most of these nerve endings originated from the petrosal ganglion. Thus, SIF cells in the superior cervical ganglion are innervated by preganglionic fibers and glossopharyngeal sensory nerve endings and can be classified into three types. SIF cells might modulate sympathetic activity in the superior cervical ganglion. PMID:25416508

  19. Incomplete segregation of endorgan-specific vestibular ganglion cells in mice and rats

    NASA Technical Reports Server (NTRS)

    Maklad, A.; Fritzsch, B.

    1999-01-01

    The endorgan-specific distribution of vestibular ganglion cells was studied in neonatal and postnatal rats and mice using indocarbocyanine dye (DiI) and dextran amines for retrograde and anterograde labeling. Retrograde DiI tracing from the anterior vertical canal labeled neurons scattered throughout the whole superior vestibular ganglion, with denser labeling at the dorsal and central regions. Horizontal canal neurons were scattered along the dorsoventral axis with more clustering toward the dorsal and ventral poles of this axis. Utricular ganglion cells occupied predominantly the central region of the superior vestibular ganglion. This utricular population overlapped with both the anterior vertical and horizontal canals' ganglion cells. Posterior vertical canal neurons were clustered in the posterior part of the inferior vestibular ganglion. The saccular neurons were distributed in the two parts of the vestibular ganglion, the superior and inferior ganglia. Within the inferior ganglion, the saccular neurons were clustered in the anterior part. In the superior ganglion, the saccular neurons were widely scattered throughout the whole ganglion with more numerous neurons at the posterior half. Small and large neurons were labeled from all endorgans. Examination of the fiber trajectory within the superior division of the vestibular nerve showed no clear lamination of the fibers innervating the different endorgans. These results demonstrate an overlapping pattern between the different populations within the superior ganglion, while in the inferior ganglion, the posterior canal and saccular neurons show tighter clustering but incomplete segregation. This distribution implies that the ganglion cells are assigned for their target during development in a stochastic rather than topographical fashion.

  20. Regional differences in myelination of chick vestibulocochlear ganglion cells.

    PubMed

    Sun, Ying-Jie; Kobayashi, Hiroto; Yoshida, Saori; Shirasawa, Nobuyuki; Naito, Akira

    2013-11-01

    In vertebrates, vestibular and cochlear ganglion (VG and CG, respectively) cells are bipolar neurons with myelinated axons and perikarya. The time course of the myelination of the VG and CG cells during development of chick embryos was investigated. Chick VG and CG from embryonic day at 7-20 (E7-20) were prepared for a transmission electron microscopy, myelin basic protein immunohistochemistry, and real-time quantitative RT-PCR. In the VG cells, myelination was first observed on the peripheral axons of the ampullar nerves at E10, on the utricular and saccular nerves at E12, and on the lagenar and neglecta nerves at E13. In the VG central axons, myelination was first seen on the ampullar nerves at E11, on the utricular and saccular nerves at E13, and on the lagenar nerves at E13. In the CG cells, the myelination was first observed on the peripheral and central axons at E14. In both VG and CG, myelination was observed on the perikarya at E17. These results suggest that the onset of the axonal myelination on the VG cells occurred earlier than that on the CG cells, whereas the perikaryal myelination occurred at about the same time on the both types of ganglion cells. Moreover, the myelination on the ampullar nerves occurred earlier than that on the utricular and saccular nerves. The myelination on the peripheral axons occurred earlier than that on the central axons of the VG cells, whereas that on the central and peripheral axons of the CG cells occurred at about the same time. The regional differences in myelination in relation to the onset of functional activities in the VG and CG cells are discussed.

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

    PubMed Central

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

    2015-01-01

    SUMMARY 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 is an area of intense debate. In mouse, anatomical estimates range between 15–20 channels, and only a handful are functionally understood. Combining two-photon calcium imaging to obtain dense retinal recordings and unsupervised clustering of the resulting sample of >11,000 cells, we here 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’s eye to the mouse’s 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. PMID:26735013

  2. Melanopsin containing retinal ganglion cells are light responsive from birth.

    PubMed

    Hannibal, Jens; Fahrenkrug, Jan

    2004-10-25

    Photoentrainment of the biological clock located in the suprachiasmatic nucleus (SCN) begins shortly after birth. Here we show using c-FOS immunoreactivity as a marker for neuronal activity that the melanopsin/PACAP containing retinal ganglion cells (RGCs) which project to the SCN as the retinohypothalamic tract (RHT) are responsive to light from birth. After postnatal day 12 where the classical photoreceptors become functional other RGCs and cells of the inner nuclear cell layer also respond to light. Light also induces c-FOS immunoreactivity in the retinorecipient SCN from the first postnatal day and accordingly PACAP immunoreactive fibres are visible in the SCN. The results indicate that the retina is light responsive before functional rods and cones and that the RHT is functional from birth supporting that photoentrainment of the biological clock begins shortly after birth.

  3. Short-wavelength cone-opponent retinal ganglion cells in mammals

    PubMed Central

    MARSHAK, DAVID W.; MILLS, STEPHEN L.

    2014-01-01

    In all of the mammalian species studied to date, the short-wavelength-sensitive (S) cones and the S-cone bipolar cells that receive their input are very similar, but the retinal ganglion cells that receive synapses from the S-cone bipolar cells appear to be quite different. Here, we review the literature on mammalian retinal ganglion cells that respond selectively to stimulation of S-cones and respond with opposite polarity to longer wavelength stimuli. There are at least three basic mechanisms to generate these color-opponent responses, including: (1) opponency is generated in the outer plexiform layer by horizontal cells and is conveyed to the ganglion cells via S-cone bipolar cells, (2) inputs from bipolar cells with different cone inputs and opposite response polarity converge directly on the ganglion cells, and (3) inputs from S-cone bipolar cells are inverted by S-cone amacrine cells. These are not mutually exclusive; some mammalian ganglion cells that respond selectively to S-cone stimulation seem to utilize at least two of them. Based on these findings, we suggest that the small bistratified ganglion cells described in primates are not the ancestral type, as proposed previously. Instead, the known types of ganglion cells in this pathway evolved from monostratified ancestral types and became bistratified in some mammalian lineages. PMID:24759445

  4. Short-wavelength cone-opponent retinal ganglion cells in mammals.

    PubMed

    Marshak, David W; Mills, Stephen L

    2014-03-01

    In all of the mammalian species studied to date, the short-wavelength-sensitive (S) cones and the S-cone bipolar cells that receive their input are very similar, but the retinal ganglion cells that receive synapses from the S-cone bipolar cells appear to be quite different. Here, we review the literature on mammalian retinal ganglion cells that respond selectively to stimulation of S-cones and respond with opposite polarity to longer wavelength stimuli. There are at least three basic mechanisms to generate these color-opponent responses, including: (1) opponency is generated in the outer plexiform layer by horizontal cells and is conveyed to the ganglion cells via S-cone bipolar cells, (2) inputs from bipolar cells with different cone inputs and opposite response polarity converge directly on the ganglion cells, and (3) inputs from S-cone bipolar cells are inverted by S-cone amacrine cells. These are not mutually exclusive; some mammalian ganglion cells that respond selectively to S-cone stimulation seem to utilize at least two of them. Based on these findings, we suggest that the small bistratified ganglion cells described in primates are not the ancestral type, as proposed previously. Instead, the known types of ganglion cells in this pathway evolved from monostratified ancestral types and became bistratified in some mammalian lineages. PMID:24759445

  5. Adaptation and dynamics of cat retinal ganglion cells.

    PubMed

    Enroth-Cugell, C; Shapley, R M

    1973-09-01

    1. The impulse/quantum (I/Q) ratio was measured as a function of background illumination for rod-dominated, pure central, linear square-wave responses of retinal ganglion cells in the cat.2. The I/Q ratio was constant at low backgrounds (dark adapted state) and inversely proportional to the 0.9 power of the background at high backgrounds (the light adapted state). There was an abrupt transition from the dark-adapted state to the light-adapted state.3. It was possible to define the adaptation level at a particular background as the ratio (I/Q ratio at that background)/(dark adapted I/Q ratio).4. The time course of the square-wave response was correlated with the adaptation level. The response was sustained in the dark-adapted state, partially transient at the transition level, and progressively more transient the lower the impulse/quantum ratio of the ganglion cell became. This was true both for on-centre and off-centre cells.5. The frequency response of the central response mechanism at different adaptation levels was measured. It was a low-pass characteristic in the dark-adapted state and became progressively more of a bandpass characteristic as the cell became more light-adapted.6. The rapidity of onset of adaptation was measured with a time-varying adapting light. The impulse/quantum ratio is reset within 100 msec of the onset of the conditioning light, and is kept at the new value throughout the time the conditioning light is on.7. These results can be explained by a nonlinear feedback model. In the model, it is postulated that the exponential function of the horizontal cell potential controls transmission from rods to bipolars. This model has an abrupt transition from dark- to light-adapted states, and its response dynamics are correlated with adaptation level.

  6. Nuclear Atrophy of Retinal Ganglion Cells Precedes the Bax-Dependent Stage of Apoptosis

    PubMed Central

    Janssen, Katherine T.; Mac Nair, Caitlin E.; Dietz, Joel A.; Schlamp, Cassandra L.; Nickells, Robert W.

    2013-01-01

    Purpose. Retinal ganglion cells atrophy during the execution of the intrinsic apoptotic program. This process, which has been termed the apoptotic volume decrease (AVD) in other cell types, has not been well-characterized in ganglion cells. Methods. Acute optic nerve crush was used to examine neuronal atrophy in the ganglion cell layer in wild-type and Bax-deficient mice. Nuclear size was measured from retinal wholemounts. Heterochromatin formation was assessed using transmission electron microscopy, whereas histone H4 acetylation was monitored using immunofluoresence. Ganglion cell and retinal transcript abundance was measured using quantitative PCR. Results. Nuclear and soma sizes linearly correlated in both control and damaged retinas. Cells in wild-type mice exhibited nuclear atrophy within 1 day after optic nerve damage. Three days after crush, nuclear atrophy was restricted to ganglion cells identified by retrograde labeling, while amacrine cells also exhibited some atrophy by 5 days. Similar kinetics of nuclear atrophy were observed in cells deficient for the essential proapoptotic gene Bax. Bax-deficient cells also exhibited other nuclear changes common in wild-type cells, including the deacetylation of histones, formation of heterochromatin, and the silencing of ganglion cell–specific gene expression. Conclusions. Retinal ganglion cell somas and nuclei undergo the AVD in response to optic nerve damage. Atrophy is rapid and precedes the Bax-dependent committed step of the intrinsic apoptotic pathway. PMID:23422829

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

    PubMed

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

    2013-09-01

    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.

  8. NBQX suppresses inhibitory glycine currents in retinal ganglion cells.

    PubMed

    Yu, W; Miller, R F

    1994-08-15

    The quinoxaline NBQX (2,3-dihydroxy-6-nitro-7-sulfamoylbenzo (F) quinoxaline) is a potent non-NMDA receptor antagonist, which appears to be relatively free of antagonistic action at the glycine binding site of the NMDA receptor. However, we report here that at 50 microM, NBQX significantly attenuated the inhibitory currents induced by the exogenous application of 100 microM glycine as observed using whole-cell recordings from ganglion cells in a slice preparation of the tiger salamander retina. In contrast, NBQX had no effect on GABA-mediated inhibition. This observation suggests that care should be taken when attributing the action of NBQX solely to its antagonism of non-NMDA glutamate receptors, particularly when higher concentrations are used.

  9. Curcumin Attenuates Staurosporine-Mediated Death of Retinal Ganglion Cells

    PubMed Central

    Burugula, Balabharathi; Ganesh, Bhagyalaxmi S.

    2011-01-01

    Purpose. Staurosporine (SS) causes retinal ganglion cell (RGC) death in vivo, but the underlying mechanisms have been unclear. Since previous studies on RGC-5 cells indicated that SS induces cell death by elevating proteases, this study was undertaken to investigate whether SS induces RGC loss by elevating proteases in the retina, and curcumin prevents SS-mediated death of RGCs. Methods. Transformed mouse retinal ganglion-like cells (RGC-5) were treated with 2.0 μM SS and various doses of curcumin. Two optimal doses of SS (12.5 and 100 nM) and curcumin (2.5 and 10 μM) were injected into the vitreous of C57BL/6 mice. Matrix metalloproteinase (MMP)-9, tissue plasminogen activator (tPA), and urokinase plasminogen activator (uPA) activities were assessed by zymography assays. Viability of RGC-5 cells was assessed by MTT assays. RGC and amacrine cell loss in vivo was assessed by immunostaining with Brn3a and ChAT antibodies, respectively. Frozen retinal cross sections were immunostained for nuclear factor-κB (NF-κB). Results. Staurosporine induced uPA and tPA levels in RGC-5 cells, and MMP-9, uPA, and tPA levels in the retinas and promoted the death of RGC-5 cells in vitro and RGCs and amacrine cells in vivo. In contrast, curcumin attenuated RGC and amacrine cell loss, despite elevated levels of proteases. An NF-κB inhibitory peptide reversed curcumin-mediated protective effect on RGC-5 cells, but did not inhibit protease levels. Curcumin did not inhibit protease levels in vivo, but attenuated RGC and amacrine cell loss by restoring NF-κB expression. Conclusions. The results show that curcumin attenuates RGC and amacrine cell death despite elevated levels of proteases and raises the possibility that it may be used as a plausible adjuvant therapeutic agent to prevent the loss of these cells in retinal degenerative conditions. PMID:21498608

  10. Target areas innervated by PACAP-immunoreactive retinal ganglion cells.

    PubMed

    Hannibal, Jens; Fahrenkrug, Jan

    2004-04-01

    The retinohypothalamic tract (RHT) originates from a subset of retinal ganglion cells (RGCs). The cells of the RHT co-store the neurotransmitters PACAP and glutamate, which in a complex interplay mediate light information to the circadian clock located in the suprachiasmatic nuclei (SCN). These ganglion cells are intrinsically photosensitive probably due to expression of melanopsin, a putative photoreceptor involved in light entrainment. In the present study we examined PACAP-containing retinal projections to the brain using intravitreal injection of the anterograde tracer cholera toxin subunit B (ChB) and double immunostaining for PACAP and ChB. Our results show that the PACAP-containing nerve fibres not only constituted the major projections to the SCN and the intergeniculate leaflet of the thalamus but also had a large terminal field in the olivary pretectal nucleus. The contralateral projection dominated except for the SCN, which showed bilateral innervation. PACAP-containing retinal fibres were also found in the ventrolateral preoptic nucleus, the anterior and lateral hypothalamic area, the subparaventricular zone, the ventral part of the lateral geniculate nucleus and the nucleus of the optic tract. Retinal projections not previously described in the rat also contained PACAP. These new projections were found in the lateral posterior nucleus, the posterior limitans nucleus, the dorsal part of the anterior pretectal nucleus and the posterior and medial pretectal nuclei. Only a few PACAP-containing retinal fibres were found in the superior colliculus. Areas innervated by PACAP-immunoreactive fibres also expressed the PACAP-specific PAC1 receptor as shown by in situ hybridization histochemistry. The findings suggest that PACAP plays a role as neurotransmitter in non-imaging photoperception to target areas in the brain regulating circadian timing, masking, regulation of sleep-wake cycle and pupillary reflex.

  11. Diffuse Bipolar Cells Provide Input to OFF Parasol Ganglion Cells in the Macaque Retina

    PubMed Central

    JACOBY, ROY A.; WIECHMANN, ALLAN F.; AMARA, SUSAN G.; LEIGHTON, BARBARA H.; MARSHAK, DAVID W.

    2012-01-01

    Parasol retinal ganglion cells are more sensitive to luminance contrast and respond more transiently at all levels of adaptation than midget ganglion cells. This may be due, in part, to differences between bipolar cells that provide their input, and the goal of these experiments was to study these differences. Midget bipolar cells are known to be presynaptic to midget ganglion cells. To identify the bipolar cells presynaptic to parasol cells, these ganglion cells were intracellularly injected with Neurobiotin, cone bipolar cells were immunolabeled, and the double-labeled material was analyzed. In the electron microscope, we found that DB3 diffuse bipolar cells labeled by using antiserum to calbindin D-28k were presynaptic to OFF parasol cells. In the confocal microscope, DB3 bipolars costratified with OFF parasol cell dendrites and made significantly more appositions with them than expected due to chance. Flat midget bipolar cells were labeled with antiserum to recoverin. Although they made a few appositions with parasol cells, the number was no greater than would be expected when two sets of processes have overlapping distributions in the inner plexiform layer. DB2 diffuse bipolar cells were labeled with antibodies to excitatory amino acid transporter 2, and they also made appositions with OFF parasol cells. These results suggest that DB2 bipolar cells are also presynaptic to OFF parasol ganglion cells, but midget bipolar cells are not. We estimate that midperipheral OFF parasol cells receive ≈500 synapses from 50 DB3 bipolar cells that, in turn, receive input from 250 cones. PMID:10578099

  12. Hyperactivity of ON-type retinal ganglion cells in streptozotocin-induced diabetic mice.

    PubMed

    Yu, Jun; Wang, Lu; Weng, Shi-Jun; Yang, Xiong-Li; Zhang, Dao-Qi; Zhong, Yong-Mei

    2013-01-01

    Impairment of visual function has been detected in the early stage of diabetes but the underlying neural mechanisms involved are largely unknown. Morphological and functional alterations of retinal ganglion cells, the final output neurons of the vertebrate retina, are thought to be the major cause of visual defects in diabetes but direct evidence to support this notion is limited. In this study we investigated functional changes of retinal ganglion cells in a type 1-like diabetic mouse model. Our results demonstrated that the spontaneous spiking activity of ON-type retinal ganglion cells was increased in streptozotocin-diabetic mice after 3 to 4 months of diabetes. At this stage of diabetes, no apoptotic signals or cell loss were detected in the ganglion cell layer of the retina, suggesting that the functional alterations in ganglion cells occur prior to massive ganglion cell apoptosis. Furthermore, we found that the increased activity of ON-type ganglion cells was mainly a result of reduced inhibitory signaling to the cells in diabetes. This novel mechanism provides insight into how visual function is impaired in diabetic retinopathy. PMID:24069457

  13. A Dopamine- and Protein Kinase A-Dependent Mechanism for Network Adaptation in Retinal Ganglion Cells

    PubMed Central

    Vaquero, C. F.; Pignatelli, A.; Partida, G. J.; Ishida, A. T.

    2011-01-01

    Vertebrates can detect light intensity changes in vastly different photic environments, in part, because post-receptoral neurons undergo “network adaptation”. Previous data implicated dopaminergic, cAMP-dependent inhibition of retinal ganglion cells in this process, yet left unclear how this occurs, and whether this occurs in darkness versus light. To test for light- and dopamine-dependent changes in ganglion cell cAMP levels in situ, we immunostained dark- and light-adapted retinas with anti-cAMP antisera, in the presence and absence of various dopamine receptor ligands. To test for direct effects of dopamine receptor ligands and membrane-permeable protein kinase ligands on ganglion cell excitability, we recorded spikes from isolated ganglion cells in perforated-patch whole-cell mode, before and during application of these agents by microperfusion. Our immunostainings show that light, endogenous dopamine, and exogenous dopamine elevate ganglion cell cAMP levels in situ by activating D1-type dopamine receptors. Our spike recordings show that D1-type agonists and 8-bromo cAMP reduce spike frequency and curtail sustained spike firing, and that these effects entail protein kinase A activation. These effects resemble those of background light on ganglion cell responses to light flashes. Network adaptation could thus be produced, to some extent, by dopaminergic modulation of ganglion cell spike generation, a mechanism distinct from modulation of transmitter release onto ganglion cells or of transmitter-gated currents in ganglion cells. Combining these observations, with results obtained in studies of photoreceptor, bipolar, and horizontal cells, indicates that all three layers of neurons in the retina are equipped with mechanisms for adaptation to ambient light. PMID:11606650

  14. Sluggish and Brisk Ganglion Cells Detect Contrast With Similar Sensitivity

    PubMed Central

    Xu, Ying; Dhingra, Narender K.; Smith, Robert G.; Sterling, Peter

    2010-01-01

    Roughly half of all ganglion cells in mammalian retina belong to the broad class, termed “sluggish.” Many of these cells have small receptive fields and project via lateral geniculate nuclei to visual cortex. However, their possible contributions to perception have been largely ignored because sluggish cells seem to respond weakly compared with the more easily studied “brisk” cells. By selecting small somas under infrared DIC optics and recording with a loose seal, we could routinely isolate sluggish cells. When a spot was matched spatially and temporally to the receptive field center, most sluggish cells could detect the same low contrasts as brisk cells. Detection thresholds for the two groups determined by an “ideal observer” were similar: threshold contrast for sluggish cells was 4.7 ± 0.5% (mean ± SE), and for brisk cells was 3.4 ± 0.3% (Mann-Whitney test: P > 0.05). Signal-to-noise ratios for the two classes were also similar at low contrast. However, sluggish cells saturated at somewhat lower contrasts (contrast for half-maximum response was 14 ± 1 vs. 19 ± 2% for brisk cells) and were less sensitive to higher temporal frequencies (when the stimulus frequency was increased from 2 to 4 Hz, the response rate fell by 1.6-fold). Thus the sluggish cells covered a narrower dynamic range and a narrower temporal bandwidth, consistent with their reported lower information rates. Because information per spike is greater at lower firing rates, sluggish cells may represent “cheaper” channels that convey less urgent visual information at a lower energy cost. PMID:15601731

  15. Broad Thorny Ganglion Cells: A Candidate for Visual Pursuit Error Signaling in the Primate Retina

    PubMed Central

    Manookin, Michael B.; Neitz, Jay; Rieke, Fred

    2015-01-01

    Functional analyses exist only for a few of the morphologically described primate ganglion cell types, and their correlates in other mammalian species remain elusive. Here, we recorded light responses of broad thorny cells in the whole-mounted macaque retina. They showed ON-OFF-center light responses that were strongly suppressed by stimulation of the receptive field surround. Spike responses were delayed compared with parasol ganglion cells and other ON-OFF cells, including recursive bistratified ganglion cells and A1 amacrine cells. The receptive field structure was shaped by direct excitatory synaptic input and strong presynaptic and postsynaptic inhibition in both ON and OFF pathways. The cells responded strongly to dark or bright stimuli moving either in or out of the receptive field, independent of the direction of motion. However, they did not show a maintained spike response either to a uniform background or to a drifting plaid pattern. These properties could be ideally suited for guiding movements involved in visual pursuit. The functional characteristics reported here permit the first direct cross-species comparison of putative homologous ganglion cell types. Based on morphological similarities, broad thorny ganglion cells have been proposed to be homologs of rabbit local edge detector ganglion cells, but we now show that the two cells have quite distinct physiological properties. Thus, our data argue against broad thorny cells as the homologs of local edge detector cells. PMID:25834063

  16. Tetrandrine protects mouse retinal ganglion cells from ischemic injury

    PubMed Central

    Li, Weiyi; Yang, Chen; Lu, Jing; Huang, Ping; Barnstable, Colin J; Zhang, Chun; Zhang, Samuel S

    2014-01-01

    This study aimed to determine the protective effects of tetrandrine (Tet) on murine ischemia-injured retinal ganglion cells (RGCs). For this, we used serum deprivation cell model, glutamate and hydrogen peroxide (H2O2)-induced RGC-5 cell death models, and staurosporine-differentiated neuron-like RGC-5 in vitro. We also investigated cell survival of purified primary-cultured RGCs treated with Tet. An in vivo retinal ischemia/reperfusion model was used to examine RGC survival after Tet administration 1 day before ischemia. We found that Tet affected RGC-5 survival in a dose- and time-dependent manner. Compared to dimethyl sulfoxide treatment, Tet increased the numbers of RGC-5 cells by 30% at 72 hours. After 48 hours, Tet protected staurosporine-induced RGC-5 cells from serum deprivation-induced cell death and significantly increased the relative number of cells cultured with 1 mM H2O2 (P<0.01). Several concentrations of Tet significantly prevented 25-mM-glutamate-induced cell death in a dose-dependent manner. Tet also increased primary RGC survival after 72 and 96 hours. Tet administration (10 μM, 2 μL) 1 day before retinal ischemia showed RGC layer loss (greater survival), which was less than those in groups with phosphate-buffered saline intravitreal injection plus ischemia in the central (P=0.005, n=6), middle (P=0.018, n=6), and peripheral (P=0.017, n=6) parts of the retina. Thus, Tet conferred protective effects on serum deprivation models of staurosporine-differentiated neuron-like RGC-5 cells and primary cultured murine RGCs. Furthermore, Tet showed greater in vivo protective effects on RGCs 1 day after ischemia. Tet and ciliary neurotrophic factor maintained the mitochondrial transmembrane potential (ΔΨm) of primary cultured RGCs and inhibited the expression of activated caspase-3 and bcl-2 in ischemia/reperfusion-insult retinas. PMID:24711693

  17. 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.

  18. Melatonin modulates M4-type ganglion-cell photoreceptors.

    PubMed

    Pack, W; Hill, D D; Wong, K Y

    2015-09-10

    In the retina, melatonin is secreted at night by rod/cone photoreceptors and serves as a dark-adaptive signal. Melatonin receptors have been found in many retinal neurons including melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs), suggesting it could modulate the physiology of these inner retinal photoreceptors. Here, we investigated whether melatonin modulates the alpha-like M4-type ipRGCs, which are believed to mediate image-forming vision as well as non-image-forming photoresponses. Applying melatonin during daytime (when endogenous melatonin secretion is low) caused whole-cell-recorded M4 cells' rod/cone-driven depolarizing photoresponses to become broader and larger, whereas the associated elevation in spike rate was reduced. Melanopsin-based light responses were not affected significantly. Nighttime application of the melatonin receptor antagonist luzindole also altered M4 cells' rod/cone-driven light responses but in the opposite ways: the duration and amplitude of the graded depolarization were reduced, whereas the accompanying spiking increase was enhanced. These luzindole-induced changes confirmed that M4 cells are modulated by endogenous melatonin. Melatonin could induce the above effects by acting directly on M4 cells because immunohistochemistry detected MT1 receptors in these cells, although it could also act presynaptically. Interestingly, the daytime and nighttime recordings showed significant differences in resting membrane potential, spontaneous spike rate and rod/cone-driven light responses, suggesting that M4 cells are under circadian control. This is the first report of a circadian variation in ipRGCs' resting properties and synaptic input, and of melatoninergic modulation of ipRGCs. PMID:26141846

  19. Microarray analysis of gene expression in adult retinal ganglion cells.

    PubMed

    Ivanov, Dmitry; Dvoriantchikova, Galina; Nathanson, Lubov; McKinnon, Stuart J; Shestopalov, Valery I

    2006-01-01

    Retinal ganglion cells (RGCs) transfer visual information to the brain and are known to be susceptible to selective degeneration in various neuropathies such as glaucoma. This selective vulnerability suggests that these highly specialized neurons possess a distinct gene expression profile that becomes altered by neuropathy-associated stresses, which lead to the RGC death. In this study, to identify genes expressed predominantly in adult RGCs, a global transcriptional profile of purified primary RGCs has been compared to that of the whole retina. To avoid alterations of the original gene expression profile by cell culture conditions, we isolated RNA directly from adult RGCs purified by immunopanning without prior sub-cultivation. Genes expressed predominantly in RGCs included: Nrg1, Rgn, 14-3-3 family (Ywhah, Ywhaz, Ywhab), Nrn1, Gap43, Vsnl1, Rgs4. Some of these genes may serve as novel markers for these neurons. Our analysis revealed enrichment in genes controlling the pro-survival pathways in RGCs as compared to other retinal cells. PMID:16376886

  20. Imaging retinal ganglion cells: enabling experimental technology for clinical application.

    PubMed

    Smith, Corey A; Chauhan, Balwantray C

    2015-01-01

    Recent advances in clinical ophthalmic imaging have enhanced patient care. However, the ability to differentiate retinal neurons, such as retinal ganglion cells (RGCs), would advance many areas within ophthalmology, including the screening and monitoring of glaucoma and other optic neuropathies. Imaging at the single cell level would take diagnostics to the next level. Experimental methods have provided techniques and insight into imaging RGCs, however no method has yet to be translated to clinical application. This review provides an overview of the importance of non-invasive imaging of RGCs and the clinically relevant capabilities. In addition, we report on experimental data from wild-type mice that received an in vivo intravitreal injection of a neuronal tracer that labelled RGCs, which in turn were monitored for up to 100 days post-injection with confocal scanning laser ophthalmoscopy. We were able to demonstrate efficient and consistent RGC labelling with this delivery method and discuss the issue of cell specificity. This type of experimental work is important in progressing towards clinically applicable methods for monitoring loss of RGCs in glaucoma and other optic neuropathies. We discuss the challenges to translating these findings to clinical application and how this method of tracking RGCs in vivo could provide valuable structural and functional information to clinicians. PMID:25448921

  1. Developmental mechanisms that regulate retinal ganglion cell dendritic morphology

    PubMed Central

    Tian, Ning

    2011-01-01

    One of the fundamental features of retinal ganglion cells (RGCs) is that dendrites of individual RGCs are confined to one or a few narrow strata within the inner plexiform layer (IPL), and each RGC synapses only with a small group of presynaptic bipolar and amacrine cells with axons/dendrites ramified in the same strata to process distinct visual features. The underlying mechanisms which control the development of this laminar-restricted distribution pattern of RGC dendrites have been extensively studied, and it is still an open question whether the dendritic pattern of RGCs is determined by molecular cues or by activity-dependent refinement. Accumulating evidence suggests that both molecular cues and activity-dependent refinement might regulate RGC dendrites in a cell subtype-specific manner. However, identification of morphological subtypes of RGCs before they have achieved their mature dendritic pattern is a major challenge in the study of RGC dendritic development. This problem is now being circumvented through the use of molecular markers in genetically engineered mouse lines to identify RGC subsets early during development. Another unanswered fundamental question in the study of activity-dependent refinement of RGC dendrites is how changes in synaptic activity lead to the changes in dendritic morphology. Recent studies have started to shed light on the molecular basis of activity-dependent dendritic refinement of RGCs by showing that some molecular cascades control the cytoskeleton reorganization of RGCs. PMID:21542137

  2. THE NISSL SUBSTANCE OF LIVING AND FIXED SPINAL GANGLION CELLS

    PubMed Central

    Deitch, Arline D.; Murray, Margaret R.

    1956-01-01

    Living chick embryo spinal ganglion neurons grown from 1 to 4 weeks in vitro were studied under the phase contrast microscope. In the peripheral cytoplasm of the earliest stages studied, a homogeneous, phase-dense material is seen which corresponds in location to the cytoplasmic basophil material of the same stages. As maturation proceeds, this material increases in extent, and becomes separated by lighter channels into discrete bodies. Short fixation by 1 per cent buffered osmium tetroxide followed by post-fixation with neutral buffered formalin does not significantly alter the size, shape, or distribution of any of the cytoplasmic components, and the fixed, hydrated cell is almost indistinguishable from the living cell. Dehydration causes some shrinkage of the fixed preparations, but if the photographs of the stained preparations are enlarged to correspond with those of the living cell, excellent correspondence can be made between at least the larger basophil masses and the larger dark masses seen with phase contrast. Fixation by a formalin-mercuric chloride procedure also results in satisfactory correspondence between the stained Nissl bodies and the phase-dark homogeneous areas. It is concluded that discrete Nissl bodies preexist in the living neuron and are essentially unchanged after good cytological fixation. Evidence is also presented of the presence of neurofibrils in the living state. PMID:13357508

  3. Bistratified ganglion cells of rabbit retina: neural architecture for contrast-independent visual responses.

    PubMed

    Famiglietti, Edward V

    2009-01-01

    Bistratified (BS) ganglion cells have long been recognized in vertebrate retina. Thirty years ago, it became clear that bistratification allows the integration of ON and OFF retinal pathways to produce contrast-independent responses in ganglion cells. Best studied is the type 1 bistratified (BS1) ganglion cell of rabbit retina, the physiologically well-characterized ON-OFF directionally selective (DS) ganglion cell, which is co-stratified with the two types of starburst amacrine (SA) cells in sublaminae a and b of the inner plexiform layer (IPL). DS responses have recently been documented in the latter. In this report, BS1 cells are further studied and are used as "fiducials" to characterize a second type of BS ganglion cell. An example of a possible third type is shown to be distinct from examples of BS1 and BS2 cells. All three have two distinct, narrowly stratified arborizations, one in sublamina a and one in sublamina b. All have similar dimensions, except for their dendritic trees, differing also in branching pattern. BS1 cells have compact, regular, highly branched trees; BS2 cells have significantly larger, more sparsely branched, irregular, radiate trees; the proposed BS3 type is intermediate in field size, and its branching pattern is different from the first two. BS2 and BS3 cells are co-stratified, branching nearer to the margins of the IPL, out of range of SA cells. In a previous report by others, illustrating the morphology of intracellularly stained ganglion cells, one example each of both "orientation-selective" ganglion cells and "uniformity detectors" resembles the BS2 cell. A rationale is presented for correlating BS2 cells with uniformity detectors.

  4. 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. PMID:27529170

  5. Melanopsin, photosensitive ganglion cells, and seasonal affective disorder.

    PubMed

    Roecklein, Kathryn A; Wong, Patricia M; Miller, Megan A; Donofry, Shannon D; Kamarck, Marissa L; Brainard, George C

    2013-03-01

    In two recent reports, melanopsin gene variations were associated with seasonal affective disorder (SAD), and in changes in the timing of sleep and activity in healthy individuals. New studies have deepened our understanding of the retinohypothalamic tract, which translates environmental light received by the retina into neural signals sent to a set of nonvisual nuclei in the brain that are responsible for functions other than sight including circadian, neuroendocrine and neurobehavioral regulation. Because this pathway mediates seasonal changes in physiology, behavior, and mood, individual variations in the pathway may explain why approximately 1-2% of the North American population develops mood disorders with a seasonal pattern (i.e., Major Depressive and Bipolar Disorders with a seasonal pattern, also known as seasonal affective disorder/SAD). Components of depression including mood changes, sleep patterns, appetite, and cognitive performance can be affected by the biological and behavioral responses to light. Specifically, variations in the gene sequence for the retinal photopigment, melanopsin, may be responsible for significant increased risk for mood disorders with a seasonal pattern, and may do so by leading to changes in activity and sleep timing in winter. The retinal sensitivity of SAD is hypothesized to be decreased compared to controls, and that further decrements in winter light levels may combine to trigger depression in winter. Here we outline steps for new research to address the possible role of melanopsin in seasonal affective disorder including chromatic pupillometry designed to measure the sensitivity of melanopsin containing retinal ganglion cells.

  6. Mosaic properties of midget and parasol ganglion cells in the marmoset retina.

    PubMed

    Szmajda, Brett A; Grünert, Ulrike; Martin, Paul R

    2005-01-01

    We measured mosaic properties of midget and parasol ganglion cells in the retina of a New World monkey, the common marmoset Callithrix jacchus . We addressed the functional specialization of these populations for color and spatial vision, by comparing the mosaic of ganglion cells in dichromatic ("red-green color blind") and trichromatic marmosets. Ganglion cells were labelled by photolytic amplification of retrograde marker ("photofilling") following injections into the lateral geniculate nucleus, or by intracellular injection in an in vitro retinal preparation. The dendritic-field size, shape, and overlap of neighboring cells were measured. We show that in marmosets, both midget and parasol cells exhibit a radial bias, so that the long axis of the dendritic field points towards the fovea. The radial bias is similar for parasol cells and midget cells, despite the fact that midget cell dendritic fields are more elongated than are those of parasol cells. The dendritic fields of midget ganglion cells from the same (ON or OFF) response-type array show very little overlap, consistent with the low coverage of the midget mosaic in humans. No large differences in radial bias, or overlap, were seen on comparing retinae from dichromatic and trichromatic animals. These data suggest that radial bias in ganglion cell populations is a consistent feature of the primate retina. Furthermore, they suggest that the mosaic properties of the midget cell population are associated with high spatial resolution rather than being specifically associated with trichromatic color vision. PMID:16212698

  7. 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.

  8. Amacrine cells in the ganglion cell layer of the cat retina.

    PubMed

    Wässle, H; Chun, M H; Müller, F

    1987-11-15

    Following transection of the optic nerve, ganglion cells in the cat retina undergo retrograde degeneration. However, many small profiles (less than or equal to 10 micron) survive in the ganglion cell layer. Previously considered to be neuroglia, there is now substantial evidence that they are displaced amacrine cells. Their density increases from approximately 1,000 cells/mm2 in peripheral retina to 7,000 cells/mm2 in the central area. Their total number was found to be 850,000, which is five times the number of ganglion cells and also five times the number of astrocytes. Uptake of 3H-muscimol followed by autoradiography labelled 75% of the displaced amacrine cells; hence, the majority seem to be GABAergic. Immunocytochemistry with an antibody directed against choline-acetyl-transferase labelled approximately 10% of the displaced amacrines in the peripheral retina and 17% in the central area. Uptake of serotonin (5-HT) followed by immunocytochemistry was found in 25-30% of displaced amacrines. NADPH diaphorase histochemistry labelled approximately 5% of displaced amacrine cells. The sum of the various percentages make colocalization likely. Intracellular injection of Lucifer Yellow under microscopic control revealed that displaced amacrine cells constitute several morphological types. PMID:3693612

  9. Opto-acoustic cell permeation

    SciTech Connect

    Visuri, S R; Heredia, N

    2000-03-09

    Optically generated acoustic waves have been used to temporarily permeate biological cells. This technique may be useful for enhancing transfection of DNA into cells or enhancing the absorption of locally delivered drugs. A diode-pumped frequency-doubled Nd:YAG laser operating at kHz repetition rates was used to produce a series of acoustic pulses. An acoustic wave was formed via thermoelastic expansion by depositing laser radiation into an absorbing dye. Generated pressures were measured with a PVDF hydrophone. The acoustic waves were transmitted to cultured and plated cells. The cell media contained a selection of normally- impermeable fluorescent-labeled dextran dyes. Following treatment with the opto-acoustic technique, cellular incorporation of dyes, up to 40,000 Molecular Weight, was noted. Control cells that did not receive opto-acoustic treatment had unremarkable dye incorporation. Uptake of dye was quantified via fluorescent microscopic analysis. Trypan Blue membrane exclusion assays and fluorescent labeling assays confirmed the vitality of cells following treatment. This method of enhanced drug delivery has the potential to dramatically reduce required drug dosages and associated side effects and enable revolutionary therapies.

  10. 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

  11. 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

  12. 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.

  13. 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. PMID:23115615

  14. 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.

  15. Effects of axotomy or target atrophy on membrane properties of rat sympathetic ganglion cells.

    PubMed Central

    Sánchez-Vives, M V; Gallego, R

    1993-01-01

    1. The electrical properties of rat superior cervical ganglion cells were examined in vitro with intracellular microelectrodes after axotomy or atrophy of the submandibular salivary gland. 2. Membrane time constant, input resistance and excitatory synaptic potentials (EPSPs) were decreased to about 50% of their control values 7-10 days after axotomy. 3. Axotomized ganglion cells also showed reduced action potentials and after-hyperpolarizations (AHPs). The AHP duration was reduced to 40% of the control value. 4. In 25% of the axotomized cells, the action potential was followed by an after-depolarization (ADP) instead of the AHP that was always present in control cells. In eleven out of seventeen axotomized cells with ADP, preganglionic stimulation failed to evoke an EPSP, whereas the failure of the synaptic response was never observed in control cells and occurred only in two of fifty-three axotomized cells with AHP. 5. In some axotomized cells with AHP, a depolarizing potential developed after a train of action potentials. This was never observed in control cells. 6. Sympathetic neurones innervating the submandibular gland in control animals had membrane properties similar to those observed in other ganglion cells. 7. The properties of neurones innervating the submandibular gland remained unaltered after the experimentally induced atrophy of the gland. 8. It is concluded that the marked effects of short-term axotomy on membrane properties of sympathetic ganglion cells are not reproduced by long-term atrophy of the target tissue. PMID:8120834

  16. 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. PMID:23018493

  17. 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.

  18. 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. PMID:21964938

  19. 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

  20. [Histoenzymologic features of adrenal medulla ganglionic cells 60 days after exposure to detergents].

    PubMed

    Devecerski, V; Marjanov, M; Milićević, S

    1993-01-01

    We investigated histochemical reactions in adrenal medulla sympathic ganglionic cells in the animals who after a 30-day stay in a detergent manufactory department survived 60 days in laboratory conditions. The obtained data show a strong isocytrate dehydrogenase activity in the experimental animals; the reaction to the lactate dehydrogenase activity reflects a decrease of the ganglionic cell volume and a slight decrease of the reaction intensity. The activity of isoenzyme F is mildly increased; similarly was found for isoenzyme S. There was a significant decrease of the succinate dehydrogenase activity--all this was detected in the animals exposed to detergents. Sympathic ganglionic cells within the adrenal medulla are rather sensitive to the influence of detergents. The recovery after the exposure to their toxic effects takes more than 2 months.

  1. Identification of AⅡ amacrine, displaced amacrine, and bistratified ganglion cell types in human retina with antibodies against calretinin.

    PubMed

    Lee, Sammy C S; Weltzien, Felix; Madigan, Michele C; Martin, Paul R; Grünert, Ulrike

    2016-01-01

    Antibodies against calretinin are markers for one type of rod pathway interneuron (AⅡ amacrine cell) in the retina of some but not all mammalian species. The AⅡ cells play a crucial role in night-time (scotopic) vision and have been proposed as a target for optogenetic restoration of vision in retinal disease. In the present study we aimed to characterize the AⅡ cells in human retina. Postmortem human donor eyes were obtained with ethical approval and processed for calretinin immunofluorescence. Calretinin-positive somas in the inner nuclear and the ganglion cell layer were filled with the lipophilic dye DiI. The large majority (over 80%) of calretinin-immunoreactive cells is located in the inner nuclear layer, is immunopositive for glycine transporter 1, and shows the typical morphology of AⅡ amacrine cells. In addition, a small proportion of calretinin-positive cells in the inner nuclear layer and in the ganglion cell layer is glutamic acid decarboxylase-positive and shows the morphology of widefield amacrine cells (stellate, semilunar, and thorny amacrine cells). About half of the calretinin cells in the ganglion cell layer are bistratified ganglion cells resembling the small bistratified (presumed blue-ON/yellow-OFF) and the G17 ganglion cell previously described in primates. We conclude that in human retina, antibodies against calretinin can be used to identify AⅡ amacrine cells in the inner nuclear layer as well as widefield amacrine and small bistratified ganglion cells in the ganglion cell layer. PMID:26053777

  2. The relation between resolution measurements and numbers of retinal ganglion cells in the same human subjects.

    PubMed

    Popovic, Zoran; Sjöstrand, Johan

    2005-08-01

    Limiting factors of resolution have previously only been investigated by using resolution data and retinal ganglion cell spacing data from different individuals. We report on our unique opportunity to study the intra-individual relationship in three human subjects between retinal ganglion cell separations and resolution thresholds, measured with high-pass resolution perimetry. Our data show that resolution is directly proportional to half the midget population, in accordance with the hypothesis that a dichotomous midget ON/OFF population mediates resolution. PMID:15924946

  3. A minute fraction of Syrian golden hamster retinal ganglion cells project bilaterally.

    PubMed

    Hsiao, K; Sachs, G M; Schneider, G E

    1984-02-01

    Bilaterally projecting retinal ganglion cells (BPRGCs) in the adult Syrian golden hamster were identified through the use of two retrogradely transported neuronal labels, horseradish peroxidase and Nuclear Yellow, placed separately in each optic tract. The distribution and size of doubly labeled retinal ganglion cells were characterized and their numbers were determined. Strict criteria were used to exclude artifactual doubly labeled cells. This work revealed that: (a) BPRGCs comprise less than 0.01% of the entire retinal ganglion cell population, averaging 7.4 (SD = 3) cells per retina; (b) BPRGCs are found primarily in the upper, peripheral retina and not along the vertical meridian or in the temporal crescent; and (c) BPRGCs correspond in size to ordinary retinal ganglion cells in their immediate vicinity, thus providing no evidence that they comprise a separate population of cells. Electrophysiological collision experiments were also performed, with stimulating electrodes in the two brachia of the superior colliculi and a recording electrode in one optic nerve. A collision effect was not detected, thus supporting the anatomical findings of rare bilateral branching of optic nerve axons. The occurrence of BPRGCs may reflect occasional ambiguities in the cues that guide axons through the chiasm.

  4. 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

  5. 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.

  6. Adult Human Nasal Mesenchymal-Like Stem Cells Restore Cochlear Spiral Ganglion Neurons After Experimental Lesion

    PubMed Central

    Bas, Esperanza; Van De Water, Thomas R.; Lumbreras, Vicente; Rajguru, Suhrud; Goss, Garrett; Hare, Joshua M.

    2014-01-01

    A loss of sensory hair cells or spiral ganglion neurons from the inner ear causes deafness, affecting millions of people. Currently, there is no effective therapy to repair the inner ear sensory structures in humans. Cochlear implantation can restore input, but only if auditory neurons remain intact. Efforts to develop stem cell-based treatments for deafness have demonstrated progress, most notably utilizing embryonic-derived cells. In an effort to bypass limitations of embryonic or induced pluripotent stem cells that may impede the translation to clinical applications, we sought to utilize an alternative cell source. Here, we show that adult human mesenchymal-like stem cells (MSCs) obtained from nasal tissue can repair spiral ganglion loss in experimentally lesioned cochlear cultures from neonatal rats. Stem cells engraft into gentamicin-lesioned organotypic cultures and orchestrate the restoration of the spiral ganglion neuronal population, involving both direct neuronal differentiation and secondary effects on endogenous cells. As a physiologic assay, nasal MSC-derived cells engrafted into lesioned spiral ganglia demonstrate responses to infrared laser stimulus that are consistent with those typical of excitable cells. The addition of a pharmacologic activator of the canonical Wnt/β-catenin pathway concurrent with stem cell treatment promoted robust neuronal differentiation. The availability of an effective adult autologous cell source for inner ear tissue repair should contribute to efforts to translate cell-based strategies to the clinic. PMID:24172073

  7. 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

  8. Sulbutiamine counteracts trophic factor deprivation induced apoptotic cell death in transformed retinal ganglion cells.

    PubMed

    Kang, Kui Dong; Majid, Aman Shah Abdul; Kim, Kyung-A; Kang, Kyungsu; Ahn, Hong Ryul; Nho, Chu Won; Jung, Sang Hoon

    2010-11-01

    Sulbutiamine is a highly lipid soluble synthetic analogue of vitamin B(1) and is used clinically for the treatment of asthenia. The aim of our study was to demonstrate whether sulbutiamine is able to attenuate trophic factor deprivation induced cell death to transformed retinal ganglion cells (RGC-5). Cells were subjected to serum deprivation for defined periods and sulbutiamine at different concentrations was added to the cultures. Various procedures (e.g. cell viability assays, apoptosis assay, reactive oxygen species analysis, Western blot analysis, flow cytometric analysis, glutathione (GSH) and glutathione-S-transferase (GST) measurement) were used to demonstrate the effect of sulbutiamine. Sulbutiamine dose-dependently attenuated apoptotic cell death induced by serum deprivation and stimulated GSH and GST activity. Moreover, sulbutiamine decreased the expression of cleaved caspase-3 and AIF. This study demonstrates for the first time that sulbutiamine is able to attenuate trophic factor deprivation induced apoptotic cell death in neuronal cells in culture. PMID:20809085

  9. Contribution of the GABAergic pathway(s) to the correlated activities of chicken retinal ganglion cells.

    PubMed

    Liu, Xue; Zhou, Yi; Gong, Hai-Qing; Liang, Pei-Ji

    2007-10-26

    In the present study, the spatiotemporal pattern of chicken retinal ganglion cells' firing activity in response to full-field white light stimulation was investigated. Cross-correlation analysis showed that ganglion cells of sustained subtype fired in precise synchrony with their adjacent neurons of the same subtype (delay lag within 2 ms, narrow correlation). On the other hand, the activities of neighboring ganglion cells of transient subtype were correlated with distributed time lags (10-30 ms, medium correlation). Pharmacological studies demonstrated that the intensity of the medium correlations could be strengthened when exogenous GABA was applied and attenuated when GABA receptors were blocked by picrotoxin. Meanwhile, the GABAergic modulation on the narrow correlations was not consistent. These results suggest that, in the chicken retina, GABAergic pathway(s) are likely involved in the formation of medium correlations between ganglion cells. Neurons might fire at a lower rate but with higher level of synchronization to improve the efficiency of information transmission, with the mechanism involving the GABAergic inhibitory input. PMID:17919471

  10. 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

  11. 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.

  12. 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.

  13. Fireworks in the primate retina: in vitro photodynamics reveals diverse LGN-projecting ganglion cell types.

    PubMed

    Dacey, Dennis M; Peterson, Beth B; Robinson, Farrel R; Gamlin, Paul D

    2003-01-01

    Diverse cell types and parallel pathways are characteristic of the vertebrate nervous system, yet it remains a challenge to define the basic components of most neural structures. We describe a process termed retrograde photodynamics that allowed us to rapidly make the link between morphology, physiology, and connectivity for ganglion cells in the macaque retina that project to the lateral geniculate nucleus (LGN). Rhodamine dextran injected into the LGN was transported retrogradely and sequestered within the cytoplasm of ganglion cell bodies. Exposure of the retina to light in vitro liberated the tracer and allowed it to diffuse throughout the dendrites, revealing the cell's complete morphology. Eight previously unknown LGN-projecting cell types were identified. Cells could also be targeted in vitro for intracellular recording and physiological analysis. The photodynamic process was also observed in pyramidal cells in a rat neocortical slice.

  14. Ganglion Cell and Displaced Amacrine Cell Density Distribution in the Retina of the Howler Monkey (Alouatta caraya)

    PubMed Central

    Muniz, José Augusto Pereira Carneiro; de Athaide, Luana Modesto; Gomes, Bruno Duarte; Finlay, Barbara L.; Silveira, Luiz Carlos de Lima

    2014-01-01

    Unlike all other New World (platyrrine) monkeys, both male and female howler monkeys (Alouatta sp.) are obligatory trichromats. In all other platyrrines, only females can be trichromats, while males are always dichromats, as determined by multiple behavioral, electrophysiological, and genetic studies. In addition to obligatory trichromacy, Alouatta has an unusual fovea, with substantially higher peak cone density in the foveal pit than every other diurnal anthropoid monkey (both platyrrhines and catarrhines) and great ape yet examined, including humans. In addition to documenting the general organization of the retinal ganglion cell layer in Alouatta, the distribution of cones is compared to retinal ganglion cells, to explore possible relationships between their atypical trichromacy and foveal specialization. The number and distribution of retinal ganglion cells and displaced amacrine cells were determined in six flat-mounted retinas from five Alouatta caraya. Ganglion cell density peaked at 0.5 mm between the fovea and optic nerve head, reaching 40,700–45,200 cells/mm2. Displaced amacrine cell density distribution peaked between 0.5–1.75 mm from the fovea, reaching mean values between 2,050–3,100 cells/mm2. The mean number of ganglion cells was 1,133,000±79,000 cells and the mean number of displaced amacrine cells was 537,000±61,800 cells, in retinas of mean area 641±62 mm2. Ganglion cell and displaced amacrine cell density distribution in the Alouatta retina was consistent with that observed among several species of diurnal Anthropoidea, both platyrrhines and catarrhines. The principal alteration in the Alouatta retina appears not to be in the number of any retinal cell class, but rather a marked gradient in cone density within the fovea, which could potentially support high chromatic acuity in a restricted central region. PMID:25546077

  15. Elevation of intracellular calcium levels in spiral ganglion cells by trimethyltin.

    PubMed

    Fechter, L D; Liu, Y

    1995-11-01

    The neurotoxicant, trimethyltin (TMT) produces cochlear impairment at far lower dose levels and far more rapidly than it does central nervous system effects. The initial effects of TMT in the cochlea, in vivo, are consistent with disruption of the inner hair cell type-1 spiral ganglion cell synapse although it is uncertain whether the effect is on presynaptic and/or postsynaptic units. This synapse is believed to be an excitatory glutamatergic one, providing the possibility that TMT could induce an excitotoxic process resulting in elevations in intracellular calcium ([Ca2+]i). The objective of this study was to determine whether TMT had direct toxic effects on the postsynaptic spiral ganglion cells studied in primary culture and to identify the role of extracellular calcium in such an effect. The marker of interest was the effect of this agent on [Ca2+]i levels as determined using quantitation of the fluorescent calcium dye, Fura-2. TMT did induce a marked and sustained elevation in [Ca2+]i level in the spiral ganglion cells that appeared to have a rapid initial phase and a slower saturating phase. Studies performed using calcium-free medium showed that elevation of [Ca2+]i in spiral ganglion cells by TMT was attenuated but not entirely blocked. Further, the L-type calcium channel blocker, nifedipine, was able to inhibit the initial increase in [Ca2+]i, suggesting that at least this phase of the TMT effect was mediated by calcium channels, although nifedipine had no significant effect on the time to reach the maximal [Ca2+]i level. Parallel control experiments performed using application of exogenous glutamate and depolarizing K+ concentrations also produced elevation in [Ca2+]i levels. The data indicate that TMT elevates [Ca2+]i in isolated spiral ganglion cells both by increasing extracellular uptake via Ca2+ channels and also by releasing Ca2+ from intracellular stores. Thus TMT ototoxicity appears to include a direct postsynaptic toxic event. PMID:8647712

  16. Homocysteine-Mediated Modulation of Mitochondrial Dynamics in Retinal Ganglion Cells

    PubMed Central

    Ganapathy, Preethi S.; Perry, Richard L.; Tawfik, Amany; Smith, Robert M.; Perry, Elizabeth; Roon, Penny; Bozard, B. Renee; Ha, Yonju

    2011-01-01

    Purpose. To evaluate the effect of excess homocysteine on the regulation of retinal ganglion cell mitochondrial dynamics. Methods. Mice deficient in cystathionine-β-synthase (cbs) were used as a model of hyperhomocysteinemia. Gene and protein expression analyses of Opa1 and Fis1 were performed on cbs+/−neural retinas. Mitochondria within retinal ganglion cell axons underwent systematic ultrastructural analysis to measure area, length, width, and the distance between the mitochondria and the axon wall. Primary mouse ganglion cells were cultured, treated with homocysteine, and assessed for levels of Opa1 and Fis1 protein, the number of mitochondria per length of neurite, and levels of cleaved caspase-3. Results. Opa1 and Fis1 protein levels in cbs+/− neural retinas were elevated to 191.00% ± 26.40% and 226.20% ± 4.57%, respectively, compared with wild-type. Mitochondria of cbs+/− retinas were smaller in all parameters studied, including area (0.32 ± 0.01μm2 vs. 0.42 ± 0.02 μm2), compared with wild-type. Primary ganglion cells treated with homocysteine had elevations in Opa1 and Fis1 proteins, a significantly higher number of mitochondria per length of neurite (0.1781 ± 0.017 vs. 0.1156 ± 0.012), and significantly higher levels of cleaved caspase-3 compared with control. Conclusions. This study provides the first evidence that homocysteine-induced ganglion cell loss involves the dysregulation of mitochondrial dynamics, both in vivo and in vitro. The present data suggest increased mitochondrial fission as a novel mechanism of homocysteine toxicity to neurons. Of particular relevance are glaucoma and Alzheimer's disease, neurodegenerative diseases that are associated with hyperhomocysteinemia and, more recently, have implicated increased mitochondrial fission in their pathogeneses. PMID:21642619

  17. Specific projection of displaced retinal ganglion cells upon the accessory optic system in the pigeon (Columbia livia).

    PubMed

    Karten, J H; Fite, K V; Brecha, N

    1977-04-01

    In the pigeon, the nucleus of the basal optic root, a component of the accessory optic system, projects directly upon the vestibulo-cerebellum. This nucleus receives a prominent projection composed of large-diameter retinal axons, known as the basal optic root. The cells of origin of this tract were identified using horseradish peroxidase (donor:hydrogen-peroxide oxidoreductase, EC 1.11.1.7) as a retrograde marker. Injections of horseradish peroxidase confined primarily to the basal optic root nucleus labeled displaced ganglion cells of the contralateral retina. Cell sizes were 18-30 micronm and the dendrites of these cells were confined to the first stratum of the inner plexiform layer. Approximately 3700 displaced ganglion cells were labeled after injections of horseradish peroxidase into basal optic root. In contrast, no displaced ganglion cells were labeled after injections of horseradish peroxidase into the optic tectum, which labeled only cells in the ganglion cell layer proper. These findings indicate that displaced ganglion cells constitute a unique population of retinal neurons that give rise to a bisynaptic pathway directed to the cerebellum via the nucleus of the basal optic root. These displaced ganglion cells may play a major role inoculomotor reflexes.

  18. 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. PMID:23595815

  19. Responses and Receptive Fields of Amacrine Cells and Ganglion Cells in the Salamander Retina

    PubMed Central

    Zhang, Ai-Jun; Wu, Samuel M.

    2013-01-01

    Retinal amacrine cells (ACs) and ganglion cells (GCs) have been shown to display large morphological diversity, and here we show that four types of ACs and three types of GCs exhibit physiologically-distinguishable properties. They are the sustained ON ACs; sustained OFF ACs; transient ON-OFF ACs; transient ON-OFF ACs with wide receptive fields; sustained ON-center/OFF-surround GCs; sustained OFF-center/ON-surround GCs and transient ON-OFF GCs. By comparing response waveforms, receptive fields and relative rod/cone inputs of ACs and GCs with the corresponding parameters of various types of the presynaptic bipolar cells (BCs), we analyze how different types of BCs mediate synaptic inputs to various ACs and GCs. Although more types of third-order retinal neurons may be identified by more refined classification criteria, our observations suggest that many morphologically-distinct ACs and GCs share very similar physiological responses. PMID:20085780

  20. Three forms of spatial temporal feedforward inhibition are common to different ganglion cell types in rabbit retina.

    PubMed

    Chen, Xin; Hsueh, Hain-Ann; Greenberg, Kenneth; Werblin, Frank S

    2010-05-01

    There exist more than 30 different morphological amacrine cell types, but there may be fewer physiological types. Here we studied the amacrine cell outputs by measuring the temporal and spatial properties of feedforward inhibition to four different types of ganglion cells. These ganglion cells, each with concentric receptive field organization, appear to receive a different relative contribution of the same three forms of feed-forward inhibition, namely: local glycinergic, local sustained GABAergic, and broad transient GABAergic inhibition. Two of these inhibitory components, local glycinergic inhibition and local sustained GABAergic inhibition were localized to narrow regions confined to the dendritic fields of the ganglion cells. The third, a broad transient GABAergic inhibition, was driven from regions peripheral to the dendritic area. Each inhibitory component is also correlated with characteristic kinetics expressed in all ganglion cells: broad transient GABAergic inhibition had the shortest latency, local glycinergic inhibition had an intermediate latency, and local sustained GABAergic inhibition had the longest latency. We suggest each of these three inhibitory components represents the output from a distinct class of amacrine cell, mediates a specific visual function, and each forms a basic functional component for the four ganglion cell types. Similar subunits likely exist in the circuits of other ganglion cell types as well.

  1. Inner retinal inhibition shapes the receptive field of retinal ganglion cells in primate

    PubMed Central

    Protti, D A; Di Marco, S; Huang, J Y; Vonhoff, C R; Nguyen, V; Solomon, S G

    2014-01-01

    Abstract The centre–surround organisation of receptive fields is a feature of most retinal ganglion cells (RGCs) and is critical for spatial discrimination and contrast detection. Although lateral inhibitory processes are known to be important in generating the receptive field surround, the contribution of each of the two synaptic layers in the primate retina remains unclear. Here we studied the spatial organisation of excitatory and inhibitory synaptic inputs onto ON and OFF ganglion cells in the primate retina. All RGCs showed an increase in excitation in response to stimulus of preferred polarity. Inhibition onto RGCs comprised two types of responses to preferred polarity: some RGCs showed an increase in inhibition whilst others showed removal of tonic inhibition. Excitatory inputs were strongly spatially tuned but inhibitory inputs showed more variable organisation: in some neurons they were as strongly tuned as excitation, and in others inhibitory inputs showed no spatial tuning. We targeted one source of inner retinal inhibition by functionally ablating spiking amacrine cells with bath application of tetrodotoxin (TTX). TTX significantly reduced the spatial tuning of excitatory inputs. In addition, TTX reduced inhibition onto those RGCs where a stimulus of preferred polarity increased inhibition. Reconstruction of the spatial tuning properties by somatic injection of excitatory and inhibitory synaptic conductances verified that TTX-mediated inhibition onto bipolar cells increases the strength of the surround in RGC spiking output. These results indicate that in the primate retina inhibitory mechanisms in the inner plexiform layer sharpen the spatial tuning of ganglion cells. PMID:24042496

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

    PubMed

    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. 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

  4. Transplantation of human adipose tissue-derived stem cells for repair of injured spiral ganglion neurons in deaf guinea pigs.

    PubMed

    Jang, Sujeong; Cho, Hyong-Ho; Kim, Song-Hee; Lee, Kyung-Hwa; Cho, Yong-Bum; Park, Jong-Seong; Jeong, Han-Seong

    2016-06-01

    Excessive noise, ototoxic drugs, infections, autoimmune diseases, and aging can cause loss of spiral ganglion neurons, leading to permanent sensorineural hearing loss in mammals. Stem cells have been confirmed to be able to differentiate into spiral ganglion neurons. Little has been reported on adipose tissue-derived stem cells (ADSCs) for repair of injured spiral ganglion neurons. In this study, we hypothesized that transplantation of neural induced-human ADSCs (NI-hADSCs) can repair the injured spiral ganglion neurons in guinea pigs with neomycin-induced sensorineural hearing loss. NI-hADSCs were induced with culture medium containing basic fibroblast growth factor and forskolin and then injected to the injured cochleae. Guinea pigs that received injection of Hanks' balanced salt solution into the cochleae were used as controls. Hematoxylin-eosin staining showed that at 8 weeks after cell transplantation, the number of surviving spiral ganglion neurons in the cell transplantation group was significantly increased than that in the control group. Also at 8 weeks after cell transplantation, immunohistochemical staining showed that a greater number of NI-hADSCs in the spiral ganglions were detected in the cell transplantation group than in the control group, and these NI-hADSCs expressed neuronal markers neurofilament protein and microtubule-associated protein 2. Within 8 weeks after cell transplantation, the guinea pigs in the cell transplantation group had a gradually decreased auditory brainstem response threshold, while those in the control group had almost no response to 80 dB of clicks or pure tone burst. These findings suggest that a large amount of NI-hADSCs migrated to the spiral ganglions, survived for a period of time, repaired the injured spiral ganglion cells, and thereby contributed to the recovery of sensorineural hearing loss in guinea pigs. PMID:27482231

  5. Transplantation of human adipose tissue-derived stem cells for repair of injured spiral ganglion neurons in deaf guinea pigs

    PubMed Central

    Jang, Sujeong; Cho, Hyong-Ho; Kim, Song-Hee; Lee, Kyung-Hwa; Cho, Yong-Bum; Park, Jong-Seong; Jeong, Han-Seong

    2016-01-01

    Excessive noise, ototoxic drugs, infections, autoimmune diseases, and aging can cause loss of spiral ganglion neurons, leading to permanent sensorineural hearing loss in mammals. Stem cells have been confirmed to be able to differentiate into spiral ganglion neurons. Little has been reported on adipose tissue-derived stem cells (ADSCs) for repair of injured spiral ganglion neurons. In this study, we hypothesized that transplantation of neural induced-human ADSCs (NI-hADSCs) can repair the injured spiral ganglion neurons in guinea pigs with neomycin-induced sensorineural hearing loss. NI-hADSCs were induced with culture medium containing basic fibroblast growth factor and forskolin and then injected to the injured cochleae. Guinea pigs that received injection of Hanks’ balanced salt solution into the cochleae were used as controls. Hematoxylin-eosin staining showed that at 8 weeks after cell transplantation, the number of surviving spiral ganglion neurons in the cell transplantation group was significantly increased than that in the control group. Also at 8 weeks after cell transplantation, immunohistochemical staining showed that a greater number of NI-hADSCs in the spiral ganglions were detected in the cell transplantation group than in the control group, and these NI-hADSCs expressed neuronal markers neurofilament protein and microtubule-associated protein 2. Within 8 weeks after cell transplantation, the guinea pigs in the cell transplantation group had a gradually decreased auditory brainstem response threshold, while those in the control group had almost no response to 80 dB of clicks or pure tone burst. These findings suggest that a large amount of NI-hADSCs migrated to the spiral ganglions, survived for a period of time, repaired the injured spiral ganglion cells, and thereby contributed to the recovery of sensorineural hearing loss in guinea pigs. PMID:27482231

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

    PubMed

    Novales Flamarique, Iñigo; Wachowiak, Matt

    2015-11-01

    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

  7. Multiple Components of Ganglion Cell Desensitization in Response to Prosthetic Stimulation

    PubMed Central

    Freeman, Daniel K; 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 neurons. Previous work indicates that repetitive stimulation with stimuli that activate the synaptic network reduces the sensitivity of retinal neurons to further stimulation. Such desensitization may contribute to the fading of visual percepts over time reported by human subjects. Here, we show that desensitization may be more complex than previously considered. We recorded spike trains from rabbit retinal ganglion cells and found that desensitization persists in the presence of inhibitory blockers (strychnine and picrotoxin), indicating amacrine cell inhibition is not solely responsible for reducing sensitivity in response to electric stimulation. The threshold for direct activation of the ganglion cell changes little during the simultaneous desensitization of the synaptically mediated response, indicating that desensitization likely occurs upstream of the spike generator. In addition to the rapid desensitization acting over hundreds of milliseconds (τ = 176.4 ± 8.8ms), we report the presence of a slow acting desensitization with a time course of seconds (τ = 14.0 ± 1.1sec). The time course of the two components of desensitization that we found are similar to the two phases of brightness fading seen in human subjects. This suggests that the reduction in ganglion cell firing due to desensitization may be responsible for the fading of visual percepts over time in response to prosthetic stimulation. PMID:21248379

  8. 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.

  9. Multiple components of ganglion cell desensitization in response to prosthetic stimulation

    NASA Astrophysics Data System (ADS)

    Freeman, Daniel K.; Fried, Shelley I.

    2011-02-01

    Retinal prostheses aim to restore functional vision to those blinded by outer retinal diseases using electric stimulation of surviving neurons. Previous work indicates that repetitive stimulation with stimuli that activate the synaptic network reduces the sensitivity of retinal neurons to further stimulation. Such desensitization may contribute to the fading of visual percepts over time reported by human subjects. Here, we show that desensitization may be more complex than previously considered. We recorded spike trains from rabbit retinal ganglion cells and found that desensitization persists in the presence of inhibitory blockers (strychnine and picrotoxin), indicating amacrine cell inhibition is not solely responsible for reducing sensitivity in response to electric stimulation. The threshold for direct activation of the ganglion cell changes little during the simultaneous desensitization of the synaptically mediated response, indicating that desensitization likely occurs upstream of the spike generator. In addition to rapid desensitization acting over hundreds of milliseconds (τ = 176.4 ± 8.8 ms), we report the presence of slow acting desensitization with a time course of seconds (τ = 14.0 ± 1.1 s). The time courses of the two components of desensitization that we found are similar to the two phases of brightness fading seen in human subjects. This suggests that the reduction in ganglion cell firing due to desensitization may be responsible for the fading of visual percepts over time in response to prosthetic stimulation.

  10. Ouabain-Induced Apoptosis in Cochlear Hair Cells and Spiral Ganglion Neurons In Vitro

    PubMed Central

    Fu, Yong; Ding, Dalian; Jiang, Haiyan; Salvi, Richard

    2013-01-01

    Ouabain is a common tool to explore the pathophysiological changes in adult mammalian cochlea in vivo. In prior studies, locally administering ouabain via round window membrane demonstrated that the ototoxic effects of ouabain in vivo varied among mammalian species. Little is known about the ototoxic effects in vitro. Thus, we prepared cochlear organotypic cultures from postnatal day-3 rats and treated these cultures with ouabain at 50, 500, and 1000 μM for different time to elucidate the ototoxic effects of ouabain in vitro and to provide insights that could explain the comparative ototoxic effects of ouabain in vivo. Degeneration of cochlear hair cells and spiral ganglion neurons was evaluated by hair-cell staining and neurofilament labeling, respectively. Annexin V staining was used to detect apoptotic cells. A quantitative RT-PCR apoptosis-focused gene array determined changes in apoptosis-related genes. The results showed that ouabain-induced damage in vitro was dose and time dependent. 500 μM ouabain and 1000 μM ouabain were destructively traumatic to both spiral ganglion neurons and cochlear hair cells in an apoptotic signal-dependent pathway. The major apoptotic pathways in ouabain-induced spiral ganglion neuron apoptosis culminated in the stimulation of the p53 pathway and triggering of apoptosis by a network of proapoptotic signaling pathways. PMID:24228256

  11. 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

  12. Differentiation of human ESCs to retinal ganglion cells using a CRISPR engineered reporter cell line.

    PubMed

    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

    2015-11-13

    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.

  13. Differentiation of human ESCs to retinal ganglion cells using a CRISPR engineered reporter cell line.

    PubMed

    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

  14. A phospholipase A₂ isolated from Lachesis muta snake venom increases the survival of retinal ganglion cells in vitro.

    PubMed

    da Silva Cunha, Karinne Cristinne; Fuly, André Lopes; de Araujo, Elizabeth Giestal

    2011-03-15

    We have previously showed that a phospholipase A₂ isolated from Lachesis muta snake venom and named LM-PLA₂-I displayed particular biological activities, as hemolysis, inhibition on platelet aggregation, edema induction and myotoxicity. In the present work, we evaluated the effect of LM-PLA₂-I on the survival of axotomized rat retinal ganglion cells kept in vitro, as well as its mechanism of action. Our results clearly showed that treatment with LM-PLA₂-I increased the survival of ganglion cells (100% when compared to control cultures) and the treatment of LM-PLA₂-I with p-bromophenacyl bromide abolished this effect. This result indicates that the effect of LM-PLA₂-I on ganglion cell survival is entirely dependent on its enzymatic activity and the generation of lysophosphatidylcholine (LPC) may be a prerequisite to the observed survival. In fact, commercial LPC mimicked the effect of LM-PLA₂-I upon ganglion cell survival. To investigate the mechanism of action of LM-PLA₂-I, cultures were treated with chelerythrine chloride, BAPTA-AM, rottlerin and also with an inhibitor of c-junc kinase (JNKi). Our results showed that rottlerin and JNK inhibitor abolished the LM-PLA₂-I on ganglion cell survival. Taken together, our results showed that LM-PLA₂-I and its enzymatic product, LPC promoted survival of retinal ganglion cells through the protein kinase C pathway and strongly suggest a possible role of the PLA₂ enzyme and LPC in controlling the survival of axotomized neuronal cells. PMID:21223976

  15. 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. PMID:18442443

  16. Connecting the eye to the brain: the molecular basis of ganglion cell axon guidance

    PubMed Central

    Oster, S F; Sretavan, D W

    2003-01-01

    In the past several years, a great deal has been learnt about the molecular basis through which specific neural pathways in the visual system are established during embryonic development. This review provides a framework for understanding the principles of retinal ganglion cell axon guidance, and introduces some of the families of axon guidance molecules involved. In addition, the potential relevance of retinal axon guidance to human visual developmental disorders, and to retinal axon regeneration, is discussed. PMID:12714414

  17. Rat neurosphere cells protect axotomized rat retinal ganglion cells and facilitate their regeneration.

    PubMed

    Hill, Andrew J; Zwart, Isabel; Samaranayake, Asanka Nuwan; Al-Allaf, Faisal; Girdlestone, John; Mehmet, Huseyin; Navarrete, Roberto; Navarrete, Cristina; Jen, Ling-Sun

    2009-07-01

    We investigated the ability of a population of rat neural stem and precursor cells derived from rat embryonic spinal cord to protect injured neurons in the rat central nervous system (CNS). The neonatal rat optic pathway was used as a model of CNS injury, whereby retinal ganglion cells (RGCs) were axotomized by lesion of the lateral geniculate nucleus one day after birth. Neural stem and precursor cells derived from expanded neurospheres (NS) were transplanted into the lesion site at the time of injury. Application of Fast Blue tracer dye to the lesion site demonstrated that significant numbers of RGCs survived at 4 and 8 weeks in animals that received a transplant, with an average of 28% survival, though in some individual cases survival was greater than 50%. No RGCs survived in animals that received a lesion alone. Furthermore, labeled RGCs were also observed when Fast Blue was applied to the superior colliculus (SC) at 4 weeks, suggesting that neurosphere cells also facilitated RGC to regenerate to their normal target. Transplanted cells did not migrate or express neural markers after transplantation, and secreted several neurotrophic factors in vitro. We conclude that NS cells can protect injured CNS neurons and promote their regeneration. These effects are not attributable to cell replacement, and may be mediated via secretion of neurotrophic factors. Thus, neuroprotection by stem cell populations may be a more viable approach for treatment of CNS disorders than cell replacement therapy.

  18. Microfluidic device for acoustic cell lysis

    SciTech Connect

    Branch, Darren W.; Cooley, Erika Jane; Smith, Gennifer Tanabe; James, Conrad D.; McClain, Jaime L.

    2015-08-04

    A microfluidic acoustic-based cell lysing device that can be integrated with on-chip nucleic acid extraction. Using a bulk acoustic wave (BAW) transducer array, acoustic waves can be coupled into microfluidic cartridges resulting in the lysis of cells contained therein by localized acoustic pressure. Cellular materials can then be extracted from the lysed cells. For example, nucleic acids can be extracted from the lysate using silica-based sol-gel filled microchannels, nucleic acid binding magnetic beads, or Nafion-coated electrodes. Integration of cell lysis and nucleic acid extraction on-chip enables a small, portable system that allows for rapid analysis in the field.

  19. 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.

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

    PubMed

    Cai, Changsi; Ren, Qiushi; Desai, Neal J; Rizzo, Joseph F; Fried, Shelley I

    2011-07-01

    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.

  1. 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

  2. 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

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

    PubMed

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

    2014-11-01

    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

  4. Mitochondrial variations in the spinal ganglion cells of the slow loris: an electron microscopic study.

    PubMed

    Ahmed, M M; Kanagasuntheram, R

    1976-04-01

    The fine structure os spinal ganglia from seven slow lorises (Nycticebus coucang coucang) was studied following perfusion fixation using different concentrations of glutaraldehyde and post-fixation in 1% osmic acid. Two cell types, one light (63%), and the other dark (37%) were reported out of the total number of 425 neurons counted. Almost all the light cells contained filamentous mitochondria, whereas only 35% of the dark cells contained filamentous mitochondria, the other 65% having vacuolated mitochondria. The significance of this mitochondrial variation in the spinal ganglion cells of the slow loris is undecided.

  5. Protein Profiling of Human Nonpigmented Ciliary Epithelium Cell Secretome: The Differentiation Factors Characterization for Retinal Ganglion Cell line

    PubMed Central

    Yang, Ming-Hui; Krishnamoorthy, Raghu R.; Jong, Shiang-Bin; Chu, Pei-Yu; Yang, Yuan-Han; Chen, Wen-Cheng; Chen, Sharon Chia-Ju; Dibas, Adnan; Yorio, Thomas; Chung, Tze-Wen; Tyan, Yu-Chang

    2011-01-01

    The purpose of this paper was to characterize proteins secreted from the human nonpigmented ciliary epithelial (HNPE) cells, which have differentiated a rat retinal ganglion cell line, RGC-5. Undifferentiated RGC-5 cells have been shown to express several marker proteins characteristic of retinal ganglion cells. However, RGC-5 cells do not respond to N-methyl-D aspartate (NMDA), or glutamate. HNPE cells have been shown to secrete numbers of neuropeptides or neuroproteins also found in the aqueous humor, many of which have the ability to influence the activity of neuronal cells. This paper details the profile of HNPE cell-secreted proteins by proteomic approaches. The experimental results revealed the identification of 132 unique proteins from the HNPE cell-conditioned SF-medium. The biological functions of a portion of these identified proteins are involved in cell differentiation. We hypothesized that a differentiation system of HNPE cell-conditioned SF-medium with RGC-5 cells can induce a differentiated phenotype in RGC-5 cells, with functional characteristics that more closely resemble primary cultures of rat retinal ganglion cells. These proteins may replace harsh chemicals, which are currently used to induce cell differentiation. PMID:21860587

  6. 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

  7. 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

  8. Growth hormone and retinal ganglion cell function: QNR/D cells as an experimental model.

    PubMed

    Martínez-Moreno, Carlos; Andres, Alexis; Giterman, Daniel; Karpinski, Edward; Harvey, Steve

    2014-01-01

    Retinal ganglion cells (RGCs) have been shown to be sites of growth hormone (GH) production and GH action in the embryonic (embryo day 7, ED7) chick neural retina. Primary RGC cell cultures were previously used to determine autocrine or paracrine actions of GH in the retina, but the antibody used in their immunopanning (anti-Thy-1) is no longer available. We have therefore characterized an immortalized neural retina (QNR/D) cell line derived from ED7 embryonic quail as a replacement experimental model. These cells express the GH gene and have GH receptor (GHR)-immunoreactivity. They are also immunoreactive for RGC markers (islet-1, calretinin, RA4) and neural fibers (neurofilament, GAP 43, vimentin) and they express the genes for Thy-1, neurotrophin 3 (NTF3), neuritin 1 (NRN1) and brn3 (POU4F). These cells are also electrically active and therefore resemble the RGCs in the neural retina. They are also similarly responsive to exogenous GH, which induces overexpression of the neurotrophin 3 and insulin-like growth factor (IGF) 1 genes and stimulates cell survival, as in the chick embryo neural retina. QNR/D cells are therefore a useful experimental model to assess the actions of GH in retinal function. PMID:24239556

  9. Acquired color vision loss and a possible mechanism of ganglion cell death in glaucoma.

    PubMed Central

    Nork, T M

    2000-01-01

    PURPOSE: First, to study the cellular mechanisms of acquired color vision loss in retinal detachment and diabetic retinopathy. Second, to learn why, in glaucoma, the type of color vision deficit that is observed is more characteristic of a retinal injury than it is of an optic neuropathy. Third, to test a hypothesis of photoreceptor-induced, ganglion cell death in glaucoma. METHODS: Various histologic techniques were employed to distinguish the L/M-cones (long/medium wavelength-sensitive cones, or red/green sensitive cones) from the S-cones (short wavelength-sensitive cones, or blue sensitive cones) in humans and monkeys with retinal detachment, humans with diabetic retinopathy, and both humans and monkeys with glaucoma. To test if the photoreceptors were contributing to ganglion cell death, laser photocoagulation was used in a experimental model of glaucoma to focally eliminate the photoreceptors. As a control, optic nerve transection was done following retinal laser photocoagulation in one animal. RESULTS: Selective and widespread loss of the S-cones was found in retinal detachment as well as diabetic retinopathy. By contrast, in human as well as experimental glaucoma, marked swelling of the L/M-cones was the predominant histopathologic feature. Retinal laser photocoagulation followed by experimental glaucoma resulted in selective protection of ganglion cells overlying the laser spots. This was not seen with retinal laser photocoagulation by optic nerve transection. CONCLUSIONS: In retinal detachment and diabetic retinopathy, acquired tritan-like color vision loss could be caused, or contributed to, by selective loss of the S-cones. Both L- and M-cones are affected in glaucoma, which is also consistent with a tritan-like deficit. Although not a therapeutic option, protection of ganglion cells by retinal laser in experimental glaucoma is consistent with an hypothesis of anterograde, photoreceptor-induced, ganglion cell death. Images FIGURE 1 FIGURE 2 FIGURE 3

  10. Identification of retinal ganglion cells and their projections involved in central transmission of information about upward and downward image motion.

    PubMed

    Yonehara, Keisuke; Ishikane, Hiroshi; Sakuta, Hiraki; Shintani, Takafumi; Nakamura-Yonehara, Kayo; Kamiji, Nilton L; Usui, Shiro; Noda, Masaharu

    2009-01-01

    The direction of image motion is coded by direction-selective (DS) ganglion cells in the retina. Particularly, the ON DS ganglion cells project their axons specifically to terminal nuclei of the accessory optic system (AOS) responsible for optokinetic reflex (OKR). We recently generated a knock-in mouse in which SPIG1 (SPARC-related protein containing immunoglobulin domains 1)-expressing cells are visualized with GFP, and found that retinal ganglion cells projecting to the medial terminal nucleus (MTN), the principal nucleus of the AOS, are comprised of SPIG1+ and SPIG1(-) ganglion cells distributed in distinct mosaic patterns in the retina. Here we examined light responses of these two subtypes of MTN-projecting cells by targeted electrophysiological recordings. SPIG1+ and SPIG1(-) ganglion cells respond preferentially to upward motion and downward motion, respectively, in the visual field. The direction selectivity of SPIG1+ ganglion cells develops normally in dark-reared mice. The MTN neurons are activated by optokinetic stimuli only of the vertical motion as shown by Fos expression analysis. Combination of genetic labeling and conventional retrograde labeling revealed that axons of SPIG1+ and SPIG1(-) ganglion cells project to the MTN via different pathways. The axon terminals of the two subtypes are organized into discrete clusters in the MTN. These results suggest that information about upward and downward image motion transmitted by distinct ON DS cells is separately processed in the MTN, if not independently. Our findings provide insights into the neural mechanisms of OKR, how information about the direction of image motion is deciphered by the AOS.

  11. Indirect activation elicits strong correlations between light and electrical responses in ON but not OFF retinal ganglion cells

    PubMed Central

    Im, Maesoon; Fried, Shelley I

    2015-01-01

    To improve the efficacy of microelectronic retinal prosthetics it will be necessary to better understand the response of retinal neurons to electric stimulation. While stimulation that directly activates ganglion cells generally has the lowest threshold, the similarity in responsiveness across cells makes it extremely difficult for such an approach to re-create cell-type specific patterns of neural activity that arise normally in the healthy retina. In contrast, stimulation that activates neurons presynaptic to ganglion cells utilizes at least some of the existing retinal circuitry and therefore is thought to produce neural activity that better matches physiological signalling. Surprisingly, the actual benefit(s) of this approach remain unsubstantiated. Here, we recorded from ganglion cells in the rabbit retinal explant in response to electrical stimuli that activated the network. Targeted cells were first classified into known types via light responses so that the consistency of electrical responses within individual types could be evaluated. Both transient and sustained ON ganglion cells exhibited highly consistent electrical response patterns which were distinct from one another. Further, properties of the response (interspike interval, latency, peak firing rate, and spike count) in a given cell were well correlated to the corresponding properties of the light response for that same cell. Electric responses in OFF ganglion cells formed two groups, distinct from ON groups, and the correlation levels between electric and light responses were much weaker. The closer match in ON pathway responses may help to explain some preferential reporting of bright stimuli during psychophysical testing. PMID:26033477

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

    PubMed Central

    Yuan, Jing; Yu, Jian-xiong

    2016-01-01

    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. PMID:27335573

  13. 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. PMID:27335573

  14. Atoh7 promotes the differentiation of Müller cells-derived retinal stem cells into retinal ganglion cells in a rat model of glaucoma.

    PubMed

    Song, Wei-tao; Zhang, Xue-yong; Xia, Xiao-bo

    2015-05-01

    Glaucoma is one of the leading eye diseases resulting in blindness due to the death of retinal ganglion cells. This study aimed to develop novel protocol to promote the differentiation of retinal Müller cells into ganglion cells in vivo in a rat model of glaucoma. The stem cells dedifferentiated from rat retinal Müller cells were randomized to receive transfection with empty lentivirus PGC-FU-GFP or lentivirus PGC-FU-Atoh7-GFP, or no transfection. The stem cells were induced further to differentiate. Ocular hypertension was induced using laser photocoagulation. The eyes were injected with Atoh7 expression vector lentivirus PGC-FU-Atoh7-GFP. Eyeball frozen sections, immunohistochemistry, RT-PCR, Western bolt, and apoptosis assay were performed. We found that the proportion of ganglion cells differentiated from Atoh7-tranfected stem cells was significantly higher than that of the other two groups. The mean intraocular pressure of glaucomatous eyes was elevated significantly compared with those of contralateral eyes. Some retinal Müller cells in the inner nuclear layer entered the mitotic cell cycle in rat chronic ocular hypertension glaucoma model. Atoh7 contributes to the differentiation of retinal Müller cells into retinal ganglion cells in rat model of glaucoma. In conclusion, Atoh7 promotes the differentiation of Müller cells-derived retinal stem cells into retinal ganglion cells in a rat model of glaucoma, thus opening up a new avenue for gene therapy and optic nerve regeneration in glaucoma.

  15. Implementing dynamic clamp with synaptic and artificial conductances in mouse retinal ganglion cells.

    PubMed

    Huang, Jin Y; Stiefel, Klaus M; Protti, Dario A

    2013-05-16

    Ganglion cells are the output neurons of the retina and their activity reflects the integration of multiple synaptic inputs arising from specific neural circuits. Patch clamp techniques, in voltage clamp and current clamp configurations, are commonly used to study the physiological properties of neurons and to characterize their synaptic inputs. Although the application of these techniques is highly informative, they pose various limitations. For example, it is difficult to quantify how the precise interactions of excitatory and inhibitory inputs determine response output. To address this issue, we used a modified current clamp technique, dynamic clamp, also called conductance clamp (1, 2, 3) and examined the impact of excitatory and inhibitory synaptic inputs on neuronal excitability. This technique requires the injection of current into the cell and is dependent on the real-time feedback of its membrane potential at that time. The injected current is calculated from predetermined excitatory and inhibitory synaptic conductances, their reversal potentials and the cell's instantaneous membrane potential. Details on the experimental procedures, patch clamping cells to achieve a whole-cell configuration and employment of the dynamic clamp technique are illustrated in this video article. Here, we show the responses of mouse retinal ganglion cells to various conductance waveforms obtained from physiological experiments in control conditions or in the presence of drugs. Furthermore, we show the use of artificial excitatory and inhibitory conductances generated using alpha functions to investigate the responses of the cells.

  16. Chloride channel protein 2 prevents glutamate-induced apoptosis in retinal ganglion cells

    PubMed Central

    Bi, Miao-Miao; Hong, Sen; Ma, Ling-Jun; Zhou, Hong-Yan; Lu, Jia; Zhao, Jing; Zheng, Ya-Juan

    2016-01-01

    Objective(s): The purpose of this study was to investigate the role of chloride channel protein 2 (ClC-2) in glutamate-induced apoptosis in the retinal ganglion cell line (RGC-5). Materials and Methods: RGC-5 cells were treated with 1 mM glutamate for 24 hr. The expression of ClC-2, Bax, and Bcl-2 was detected by western blot analysis. Cell survival and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. Caspase-3 and -9 activities were determined by a colorimetric assay. The roles of ClC-2 in glutamate-induced apoptosis were examined by using ClC-2 complementary deoxyribonucleic acid (cDNA) and small inference ribonucleic acid (RNA) transfection technology. Results: Overexpression of ClC-2 in RGC-5 cells significantly decreased glutamate-induced apoptosis and increased cell viability, whereas silencing of ClC-2 with short hairpin (sh) RNA produced opposite effects. ClC-2 overexpression increased the expression of Bcl-2, decreased the expression of Bax, and decreased caspase-3 and -9 activation in RGC-5 cells treated with glutamate, but silencing of ClC-2 produced opposite effects. Conclusion: Our data suggest that ClC-2 chloride channels might play a protective role in glutamate-induced apoptosis in retinal ganglion cells via the mitochondria-dependent apoptosis pathway.

  17. Chloride channel protein 2 prevents glutamate-induced apoptosis in retinal ganglion cells

    PubMed Central

    Bi, Miao-Miao; Hong, Sen; Ma, Ling-Jun; Zhou, Hong-Yan; Lu, Jia; Zhao, Jing; Zheng, Ya-Juan

    2016-01-01

    Objective(s): The purpose of this study was to investigate the role of chloride channel protein 2 (ClC-2) in glutamate-induced apoptosis in the retinal ganglion cell line (RGC-5). Materials and Methods: RGC-5 cells were treated with 1 mM glutamate for 24 hr. The expression of ClC-2, Bax, and Bcl-2 was detected by western blot analysis. Cell survival and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. Caspase-3 and -9 activities were determined by a colorimetric assay. The roles of ClC-2 in glutamate-induced apoptosis were examined by using ClC-2 complementary deoxyribonucleic acid (cDNA) and small inference ribonucleic acid (RNA) transfection technology. Results: Overexpression of ClC-2 in RGC-5 cells significantly decreased glutamate-induced apoptosis and increased cell viability, whereas silencing of ClC-2 with short hairpin (sh) RNA produced opposite effects. ClC-2 overexpression increased the expression of Bcl-2, decreased the expression of Bax, and decreased caspase-3 and -9 activation in RGC-5 cells treated with glutamate, but silencing of ClC-2 produced opposite effects. Conclusion: Our data suggest that ClC-2 chloride channels might play a protective role in glutamate-induced apoptosis in retinal ganglion cells via the mitochondria-dependent apoptosis pathway. PMID:27635193

  18. 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

  19. A model of high-frequency oscillatory potentials in retinal ganglion cells

    PubMed Central

    KENYON, GARRETT T.; MOORE, BARTLETT; JEFFS, JANELLE; DENNING, KATE S.; STEPHENS, GREG J.; TRAVIS, BRYAN J.; GEORGE, JOHN S.; THEILER, JAMES; MARSHAK, DAVID W.

    2012-01-01

    High-frequency oscillatory potentials (HFOPs) have been recorded from ganglion cells in cat, rabbit, frog, and mudpuppy retina and in electroretinograms (ERGs) from humans and other primates. However, the origin of HFOPs is unknown. Based on patterns of tracer coupling, we hypothesized that HFOPs could be generated, in part, by negative feedback from axon-bearing amacrine cells excited via electrical synapses with neighboring ganglion cells. Computer simulations were used to determine whether such axon-mediated feedback was consistent with the experimentally observed properties of HFOPs. (1) Periodic signals are typically absent from ganglion cell PSTHs, in part because the phases of retinal HFOPs vary randomly over time and are only weakly stimulus locked. In the retinal model, this phase variability resulted from the nonlinear properties of axon-mediated feedback in combination with synaptic noise. (2) HFOPs increase as a function of stimulus size up to several times the receptive-field center diameter. In the model, axon-mediated feedback pooled signals over a large retinal area, producing HFOPs that were similarly size dependent. (3) HFOPs are stimulus specific. In the model, gap junctions between neighboring neurons caused contiguous regions to become phase locked, but did not synchronize separate regions. Model-generated HFOPs were consistent with the receptive-field center dynamics and spatial organization of cat alpha cells. HFOPs did not depend qualitatively on the exact value of any model parameter or on the numerical precision of the integration method. We conclude that HFOPs could be mediated, in part, by circuitry consistent with known retinal anatomy. PMID:14977326

  20. T cell-mediated paraneoplastic ganglionitis--an autopsy case.

    PubMed

    Drlicek, M; Bodenteich, A; Setinek, U; Tucek, G; Urbanits, S; Grisold, W

    2000-05-01

    A 57-year-old woman presented with subacute sensory, ataxic neuronopathy. Clinical investigation revealed a right-sided non-small-cell lung cancer. Serum investigation for specific antineuronal antibodies was negative. Histology showed T lymphocytic infiltrates in dorsal root ganglia. The observed histological pattern is similar to that described in antibody-positive cases. Thus, these findings suggest similar pathways in specific antineuronal antibody-negative and -positive cases of paraneoplastic subacute sensory neuronopathy.

  1. Concomitant activation of two types of glutamate receptor mediates excitation of salamander retinal ganglion cells.

    PubMed Central

    Mittman, S; Taylor, W R; Copenhagen, D R

    1990-01-01

    1. Cells in the ganglion cell layer of salamander retinal slices were voltage clamped using patch pipettes. Light elicited transient excitatory postsynaptic currents (EPSCs) in on-off ganglion cells and sustained EPSCs in on ganglion cells. Light-evoked inhibitory postsynaptic currents in these cells could be blocked by 100 microM-bicuculline methobromide and 500 nM-strychnine. 2. In the presence of external Cd2+, at a concentration that blocked light-evoked synaptic inputs, N-methyl-D-aspartate (NMDA) and the non-NMDA-receptor agonists, quisqualate and kainate, gated conductances in both on-off and on ganglion cells. The current-voltage (I-V) curve for the conductance elicited by NMDA had a negative slope between -40 and -70 mV and a reversal potential near 0 mV. The I-V curves for the non-NMDA-receptor-mediated conductances were nearly linear and also had reversal potentials near 0 mV. 3. I-V curves were measured at an early time point near the peak of transient EPSCs and at a later time point during the decay phase of the responses. The late I-V curve had a negative slope below -40 mV. The early I-V curve had a positive slope over the entire voltage range but the slope was greater at positive than at negative potentials. The evoked current reversed near 0 mV at both time points. 4. The region of negative slope of the late I-V curve was eliminated when Mg2+ was removed from the external saline. A slowly decaying component of transient EPSCs was eliminated in 20 microM-DL-2-amino-7-phosphonoheptanoate (AP7), an NMDA-receptor antagonist. 5. Application of 1 microM-6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA-receptor antagonist at this concentration, blocked a fast component of transient EPSCs. 6. Our results demonstrate that the synaptic inputs to on-off ganglion cells have two components: a slower NMDA-receptor-mediated component having a time-to-peak of 110 +/- 45 ms and an e-fold decay time of 209 +/- 35 ms at -31 mV (mean +/- S.D., n = 5), and a

  2. Cyan fluorescent protein expression in ganglion and amacrine cells in a thy1-CFP transgenic mouse retina

    PubMed Central

    Vila, Alejandro; Huynh, Uyen-Chi N.; Brecha, Nicholas C.

    2008-01-01

    Purpose To characterize cyan fluorescent protein (CFP) expression in the retina of the thy1-CFP (B6.Cg-Tg(Thy1-CFP)23Jrs/J) transgenic mouse line. Methods CFP expression was characterized using morphometric methods and immunohistochemistry with antibodies to neurofilament light (NF-L), neuronal nuclei (NeuN), POU-domain protein (Brn3a) and calretinin, which immunolabel ganglion cells, and syntaxin 1 (HPC-1), glutamate decarboxylase 67 (GAD67), GABA plasma membrane transporter-1 (GAT-1), and choline acetyltransferase (ChAT), which immunolabel amacrine cells. Results CFP was extensively expressed in the inner retina, primarily in the inner plexiform layer (IPL), ganglion cell layer (GCL), nerve fiber layer, and optic nerve. CFP fluorescent cell bodies were in all retinal regions and their processes ramified in all laminae of the IPL. Some small, weakly CFP fluorescent somata were in the inner nuclear layer (INL). CFP-containing somata in the GCL ranged from 6 to 20 μm in diameter, and they had a density of 2636±347 cells/mm2 at 1.5 mm from the optic nerve head. Immunohistochemical studies demonstrated colocalization of CFP with the ganglion cell markers NF-L, NeuN, Brn3a, and calretinin. Immunohistochemistry with antibodies to HPC-1, GAD67, GAT-1, and ChAT indicated that the small, weakly fluorescent CFP cells in the INL and GCL were cholinergic amacrine cells. Conclusions The total number and density of CFP-fluorescent cells in the GCL were within the range of previous estimates of the total number of ganglion cells in the C57BL/6J line. Together these findings suggest that most ganglion cells in the thy1-CFP mouse line 23 express CFP. In conclusion, the thy1-CFP mouse line is highly useful for studies requiring the identification of ganglion cells. PMID:18728756

  3. Degeneration of spiral ganglion cells in the chinchilla after inner hair cell loss induced by carboplatin.

    PubMed

    Takeno, S; Wake, M; Mount, R J; Harrison, R V

    1998-01-01

    The anticancer drug carboplatin has been used to generate inner hair cell (IHC) lesions in the cochlea of chinchillas. This has provided a valuable model for the study of the relative roles of IHCs and outer hair cells (OHCs). In the present study, we examined the pathological and temporal relationships between the degeneration of the cochlear IHCs and type I spiral ganglion cells (SGCs). A single intravenous dose of 200 mg/m2 carboplatin produced extensive IHC loss with no apparent effect on the OHCs. The auditory brainstem response threshold was significantly elevated by 2 weeks following treatment and remained stable through 12 weeks. Elevated thresholds were well correlated with morphological lesions. On the other hand, the SGC population progressively decreased from 2 to 12 weeks after treatment, to about half of the control density values. A positive correlation existed between the density of SGC and the number of surviving IHCs. These results indicate that selective damage to IHCs causes a distinct loss of SGCs. PMID:9705525

  4. Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.

    PubMed

    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

    2016-02-01

    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

  5. Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.

    PubMed

    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

    2016-02-01

    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.

  6. Adenosine modulates light responses of rat retinal ganglion cell photoreceptors througha cAMP-mediated pathway

    PubMed Central

    Sodhi, Puneet; Hartwick, Andrew T E

    2014-01-01

    Adenosine is an established neuromodulator in the mammalian retina, with A1 adenosine receptors being especially prevalent in the innermost ganglion cell layer. Activation of A1 receptors causes inhibition of adenylate cyclase, decreases in intracellular cyclic AMP (cAMP) levels and inhibition of protein kinase A (PKA). In this work, our aim was to characterize the effects of adenosine on the light responses of intrinsically photosensitive retinal ganglion cells (ipRGCs) and to determine whether these photoreceptors are subject to neuromodulation through intracellular cAMP-related signalling pathways. Using multielectrode array recordings from postnatal and adult rat retinas, we demonstrated that adenosine significantly shortened the duration of ipRGC photoresponses and reduced the number of light-evoked spikes fired by these neurons. The effects were A1 adenosine receptor-mediated, and the expression of this receptor on melanopsin-containing ipRGCs was confirmed by calcium imaging experiments on isolated cells in purified cultures. While inhibition of the cAMP/PKA pathway by adenosine shortened ipRGC light responses, stimulation of this pathway with compounds such as forskolin had the opposite effect and lengthened the duration of ipRGC spiking. Our findings reveal that the modification of ipRGC photoresponses through a cAMP/PKA pathway is a general feature of rat ganglion cell photoreceptors, and this pathway can be inhibited through activation of A1 receptors by adenosine. As adenosine levels in the retina rise at night, adenosinergic modulation of ipRGCs may serve as an internal regulatory mechanism to limit transmission of nocturnal photic signals by ipRGCs to the brain. Targeting retinal A1 adenosine receptors for ipRGC inhibition represents a potential therapeutic target for sleep disorders and migraine-associated photophobia. PMID:25038240

  7. 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.

  8. 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

  9. 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. PMID:24465283

  10. 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.

  11. Role of CtBP2 in the Apoptosis of Retinal Ganglion Cells.

    PubMed

    Wang, Wenwen; Zhang, Guowei; Gu, Hui; Liu, Ye; Lao, Jifeng; Li, Kuifang; Guan, Huaijin

    2015-07-01

    Glaucoma damages the optic nerve and is a leading cause of irreversible blindness, and its pathogenesis remains unclear. C-terminal-binding protein 2 (CtBP2) is a transcriptional repressor which plays an important role in central nervous system injury and repair. Using the glaucoma model of DBA/2J mouse whose retina ganglion cells (RGCs) were degenerating with the process of glaucoma, we demonstrated for the first time the special relationship between CtBP2 protein and RGCs. Our research indicated that the expression of CtBP2 was gradually decreased with aging by the means of Western blotting. The CtBP2 immunoreactivity-positive cells were present in the various retinal layers, and CtBP2-positive cells were dramatically decreased in ganglion cell layer. Our research also found ectopic expression of CtBP2 can protect the apoptosis of primary mouse RGC cells induced by L-glutamate. These results suggest that CtBP2 may have a potential therapeutic effect in protecting RGC.

  12. 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

  13. Visual responses of ganglion cells of a New-World primate, the capuchin monkey, Cebus apella

    PubMed Central

    Lee, Barry B; Silveira, Luiz Carlos L; Yamada, Elizabeth S; Hunt, David M; Kremers, Jan; Martin, Paul R; Troy, John B; da Silva-Filho, Manoel

    2000-01-01

    The genetic basis of colour vision in New-World primates differs from that in humans and other Old-World primates. Most New-World primate species show a polymorphism; all males are dichromats and most females trichromats. In the retina of Old-World primates such as the macaque, the physiological correlates of trichromacy are well established. Comparison of the retinae in New- and Old-World species may help constrain hypotheses as to the evolution of colour vision and the pathways associated with it. Ganglion cell behaviour was recorded from trichromatic and dichromatic members of a New-World species (the capuchin monkey, Cebus apella) and compared with macaque data. Despite some differences in quantitative detail (such as a temporal response extended to higher frequencies), results from trichromatic animals strongly resembled those from the macaque. In particular, cells of the parvocellular (PC) pathway showed characteristic frequency-dependent changes in responsivity to luminance and chromatic modulation, cells of the magnocellular (MC) pathway showed frequency-doubled responses to chromatic modulation, and the surround of MC cells received a chromatic input revealed on changing the phase of heterochromatically modulated lights. Ganglion cells of dichromats were colour-blind versions of those of trichromats. This strong physiological homology is consistent with a common origin of trichromacy in New- and Old-World monkeys; in the New-World primate the presence of two pigments in the middle-to-long wavelength range permits full expression of the retinal mechanisms of trichromatic vision. PMID:11432364

  14. Eye Histology and Ganglion Cell Topography of Northern Elephant Seals (Mirounga angustirostris).

    PubMed

    Smodlaka, Hrvoje; Khamas, Wael A; Palmer, Lauren; Lui, Bryan; Borovac, Josip A; Cohn, Brian A; Schmitz, Lars

    2016-06-01

    Northern elephant seals are one of the deepest diving marine mammals. As northern elephant seals often reach the bathypelagic zone, it is usually assumed that their eyes possess evolutionary adaptations that provide better ability to see in dim or scotopic environments. The purpose of this study was to carefully describe anatomical and histological traits of the eye that may improve light sensitivity. Northern elephant seals have large, somewhat elliptical eyes, with equatorial and anteroposterior diameters of 5.03 and 4.4 cm, respectively. The cornea is large in diameter and the lens is completely spherical. The iris has pronounced constrictor and dilator muscles, whereas the ciliary muscle is notably less developed. The tapetum lucidum is more prominent than in other pinnipeds, making up about 63% of retinal thickness in the posterior aspect of the globe. Within the retina, the pigmented epithelium lacks pigment except for the region close to the ora serrata. Parts of the photoreceptor and outer nuclear layers are folded. Although the photoreceptor layer is composed predominantly of rods, cone photoreceptors were also observed. Cells within the retinal ganglion cell layer are arranged in a single level. Ganglion cells reach their maximum density (∼1,300 cells per mm(2) ) dorsal to the optic disc, whereas the periphery of the retina is sparsely populated (<100 cells per mm(2) ). All above mentioned features are consistent with the predicted evolutionary adaptations to the photic environment of the bathypelagic zone. Anat Rec, 299:798-805, 2016. © 2016 Wiley Periodicals, Inc.

  15. 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

  16. Retrograde labeling, enrichment, and characterization of retinal ganglion cells from the neonatal rat.

    PubMed

    Sarthy, P V; Curtis, B M; Catterall, W A

    1983-12-01

    We have developed a method for labeling retinal ganglion cells in neonatal rats by retrograde transport of the fluorescent dye, True Blue (TB), injected into the optic chiasm. Following proteolytic dissociation of labeled retinas into single cells, the labeled cells could be enriched 50- to 100-fold by centrifugation in a 5%/10% metrizamide gradient. When plated in Ham's F-10 medium in the presence of fetal calf serum and chick optic tectum-conditioned medium, the labeled cells could be maintained in vitro up to 48 hr. In these cultures, the ganglion cells (GCS) constituted 50 to 70% of the total cell population. When GC-rich fractions or GC cultures were stained with a monoclonal antibody to Thy-1 antigen, greater than 90% of the TB-labeled cells were reactive. In order to localize voltage-sensitive sodium channels, GC-rich cultures were reacted with 125I-scorpion toxin. Analysis of the autoradiograms showed that the density of silver grains was about 10-fold higher on TB-labeled cells than on nonfluorescent cells, or in controls which contained excess of unlabeled toxin. When GC cultures were incubated with micromolar concentrations of putative GC transmitters, aspartate and glutamate, the amino acids were accumulated by 15 to 20% of labeled cells. Several lectin receptors were also localized on TB-labeled cells in situ. Whereas the lectins wheat germ agglutinin, concanavalin A, peanut agglutinin, Dolichos biflorus agglutinin, and Limulus polyphemus agglutinin bound to TB-labeled cells, others such as Ricinus communis agglutinin I, Ulex, and Lotus lectins showed no binding. The lectin binding was specific since preincubation with the appropriate hapten sugar blocked lectin binding.

  17. Gibbs distribution analysis of temporal correlations structure in retina ganglion cells

    PubMed Central

    Vasquez, J. C.; Marre, O.; Palacios, A.G.; Berry, M.J.; Cessac, B.

    2012-01-01

    We present a method to estimate Gibbs distributions with spatio-temporal constraints on spike trains statistics. We apply this method to spike trains recorded from ganglion cells of the salamander retina, in response to natural movies. Our analysis, restricted to a few neurons, performs more accurately than pairwise synchronization models (Ising) or the 1-time step Markov models (Marre et al. (2009)) to describe the statistics of spatio-temporal spike patterns and emphasizes the role of higher order spatio-temporal interactions. PMID:22115900

  18. 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

  19. The first stage of cardinal direction selectivity is localized to the dendrites of retinal ganglion cells.

    PubMed

    Yonehara, Keisuke; Farrow, Karl; Ghanem, Alexander; Hillier, Daniel; Balint, Kamill; Teixeira, Miguel; Jüttner, Josephine; Noda, Masaharu; Neve, Rachael L; Conzelmann, Karl-Klaus; Roska, Botond

    2013-09-18

    Inferring the direction of image motion is a fundamental component of visual computation and essential for visually guided behavior. In the retina, the direction of image motion is computed in four cardinal directions, but it is not known at which circuit location along the flow of visual information the cardinal direction selectivity first appears. We recorded the concerted activity of the neuronal circuit elements of single direction-selective (DS) retinal ganglion cells at subcellular resolution by combining GCaMP3-functionalized transsynaptic viral tracing and two-photon imaging. While the visually evoked activity of the dendritic segments of the DS cells were direction selective, direction-selective activity was absent in the axon terminals of bipolar cells. Furthermore, the glutamate input to DS cells, recorded using a genetically encoded glutamate sensor, also lacked direction selectivity. Therefore, the first stage in which extraction of a cardinal motion direction occurs is the dendrites of DS cells.

  20. Neural architecture of the "transient" ON directionally selective (class IIb1) ganglion cells in rabbit retina, partly co-stratified with starburst amacrine cells.

    PubMed

    Famiglietti, Edward V

    2016-01-01

    Recent physiological studies coupled with intracellular staining have subdivided ON directionally selective (DS) ganglion cells of rabbit retina into two types. One exhibits more "transient" and more "brisk" responses (ON DS-t), and the other has more "sustained' and more "sluggish" responses (ON DS-s), although both represent the same three preferred directions and show preference for low stimulus velocity, as reported in previous studies of ON DS ganglion cells in rabbit retina. ON DS-s cells have the morphology of ganglion cells previously shown to project to the medial terminal nucleus (MTN) of the accessory optic system, and the MTN-projecting, class IVus1 cells have been well-characterized previously in terms of their dendritic morphology, branching pattern, and stratification. ON DS-t ganglion cells have a distinctly different morphology and exhibit heterotypic coupling to amacrine cells, including axon-bearing amacrine cells, with accompanying synchronous firing, while ON DS-s cells are not coupled. The present study shows that ON DS-t cells are morphologically identical to the previously well-characterized, "orphan" class IIb1 ganglion cell, previously regarded as a member of the "brisk-concentric" category of ganglion cells. Its branching pattern, quantitatively analyzed, is similar to that of the morphological counterparts of X and Y cells, and very different from that of the ON DS-s ganglion cell. Close analysis of the dendritic stratification of class IIb1 ganglion cells together with fiducial cells indicates that they differ from that of the ON DS-s cells. In agreement with one of the three previous studies, class IIb1/ON DS-t cells, unlike class IVus1/ON DS-s ganglion cells, in the main do not co-stratify with starburst amacrine cells. As the present study shows, however, portions of their dendrites do deviate from the main substratum, coming within range of starburst boutons. Parsimony favors DS input from starburst amacrine cells both to ON DS

  1. Parallel cone bipolar pathways to a ganglion cell use different rates and amplitudes of quantal excitation.

    PubMed

    Freed, M A

    2000-06-01

    The cone signal reaches the cat's On-beta (X) ganglion cell via several parallel circuits (bipolar cell types b1, b2, and b3). These circuits might convey different regions of the cone's temporal bandwidth. To test this, I presented a step of light that elicited a transient depolarization followed by a sustained depolarization. The contribution of bipolar cells to these response components was isolated by blocking action potentials with tetrodotoxin and by blocking inhibitory synaptic potentials with bicuculline and strychnine. Stationary fluctuation analysis of the sustained depolarization gave the rate of quantal bombardment: approximately 5100 quanta sec(-1) for small central cells and approximately 45,000 quanta sec(-1) for large peripheral cells. Normalizing these rates for the vastly different numbers of bipolar synapses (150-370 per small cell vs 2000 per large cell), quantal rate was constant across the retina, approximately 22 quanta synapse(-1) sec(-1). Nonstationary fluctuation analysis gave the mean quantal EPSP amplitude: approximately 240 microV for the transient depolarization and 30 microV for the sustained depolarization. The b1 bipolar cell is known from noise analysis of the On-alpha ganglion cell to have a near-maximal sustained release of only approximately two quanta synapse(-1) sec(-1). This implies that the other bipolar types (b2 and b3) contribute many more quanta to the sustained depolarization (>/=46 synapse(-1) sec(-1)). Type b1 probably contributes large quanta to the transient depolarization. Thus, bipolar cell types b1 and b2/b3 apparently constitute parallel circuits that convey, respectively, high and low frequencies. PMID:10818130

  2. Quantitative analysis of the retinal ganglion cell layer and optic nerve of the barn owl Tyto alba.

    PubMed

    Wathey, J C; Pettigrew, J D

    1989-01-01

    The visual capacity of the common barn owl (Tyto alba) was studied by quantitative analysis of the retina and optic nerve. Cell counts in the ganglion cell layer of the whole-mounted retina revealed a temporal area centralis with peak cell density of 12,500 cells/mm2 and a horizontal streak of high cell density extending from the area centralis into the nasal retina. Integration of the ganglion cell density map gave an estimated total of 1.4 million cells for the ganglion cell layer. Electron microscopy of a single, complete section of the optic nerve revealed a bimodal fiber diameter spectrum (modes at 0.3 and 0.9 microns; bin width = 0.2 microns), with diameters ranging from 0.15 microns (unmyelinated) to 6.05 microns (myelinated, sheath included). The total axon count for the optic nerve was estimated from sample counts to be about 680,000 axons (25% unmyelinated). Therefore, roughly half of the cells in the retinal ganglion cell layer do not send axons into the optic nerve. With certain assumptions, the data predict a visual spatial acuity for barn owls on the order of 8 cycles/degree, a value similar to the known behaviorally measured acuities of masked owls (10 cycles/degree) and domestic cats (6 cycles/degree). PMID:2758316

  3. The RNA binding protein RBPMS is a selective marker of ganglion cells in the mammalian retina

    PubMed Central

    Rodriguez, Allen R.; de Sevilla Müller, Luis Pérez; Brecha, Nicholas C.

    2014-01-01

    There are few neurochemical markers that reliably identify retinal ganglion cells (RGCs), which are a heterogeneous population of cells that integrate and transmit the visual signal from the retina to the central visual nuclei. We have developed and characterized a new set of affinity purified guinea pig and rabbit antibodies against RNA-binding protein with multiple splicing (RBPMS). On Western blots these antibodies recognize a single band at ~24 kDa, corresponding to RBPMS, and they strongly label RGC and displaced RGC (dRGC) somata in mouse, rat, guinea pig, rabbit and monkey retina. RBPMS immunoreactive cells and RGCs identified by other techniques have a similar range of somal diameters and areas. The density of RBPMS cells in mouse and rat retina is comparable to earlier semi-quantitative estimates of RGCs. RBPMS is mainly expressed in medium and large DAPI-, DRAQ5-, NeuroTrace- and NeuN-stained cells in the ganglion cell layer (GCL), and RBPMS is not expressed in syntaxin (HPC-1) immunoreactive cells in the inner nuclear layer (INL) and GCL, consistent with their identity as RGCs, and not displaced amacrine cells. In mouse and rat retina, most RBPMS cells are lost following optic nerve crush or transection at three weeks, and all Brn3a, SMI-32 and melanopsin immunoreactive RGCs also express RBPMS immunoreactivity. RBPMS immunoreactivity is localized to CFP-fluorescent RGCs in the B6.Cg-Tg(Thy1-CFP)23Jrs/J mouse line. These findings show that antibodies against RBPMS are robust reagents that exclusively identify RGCs and dRGCs in multiple mammalian species, and they will be especially useful for quantification of RGCs. PMID:24318667

  4. Primary culture of glial cells from mouse sympathetic cervical ganglion: a valuable tool for studying glial cell biology.

    PubMed

    de Almeida-Leite, Camila Megale; Arantes, Rosa Maria Esteves

    2010-12-15

    Central nervous system glial cells as astrocytes and microglia have been investigated in vitro and many intracellular pathways have been clarified upon various stimuli. Peripheral glial cells, however, are not as deeply investigated in vitro despite its importance role in inflammatory and neurodegenerative diseases. Based on our previous experience of culturing neuronal cells, our objective was to standardize and morphologically characterize a primary culture of mouse superior cervical ganglion glial cells in order to obtain a useful tool to study peripheral glial cell biology. Superior cervical ganglia from neonatal C57BL6 mice were enzymatically and mechanically dissociated and cells were plated on diluted Matrigel coated wells in a final concentration of 10,000cells/well. Five to 8 days post plating, glial cell cultures were fixed for morphological and immunocytochemical characterization. Glial cells showed a flat and irregular shape, two or three long cytoplasm processes, and round, oval or long shaped nuclei, with regular outline. Cell proliferation and mitosis were detected both qualitative and quantitatively. Glial cells were able to maintain their phenotype in our culture model including immunoreactivity against glial cell marker GFAP. This is the first description of immunocytochemical characterization of mouse sympathetic cervical ganglion glial cells in primary culture. This work discusses the uses and limitations of our model as a tool to study many aspects of peripheral glial cell biology.

  5. Expression of polysialylated neural cell adhesion molecules on adult stem cells after neuronal differentiation of inner ear spiral ganglion neurons

    SciTech Connect

    Park, Kyoung Ho; Yeo, Sang Won; Troy, Frederic A.

    2014-10-17

    Highlights: • PolySia expressed on neurons primarily during early stages of neuronal development. • PolySia–NCAM is expressed on neural stem cells from adult guinea pig spiral ganglion. • PolySia is a biomarker that modulates neuronal differentiation in inner ear stem cells. - Abstract: During brain development, polysialylated (polySia) neural cell adhesion molecules (polySia–NCAMs) modulate cell–cell adhesive interactions involved in synaptogenesis, neural plasticity, myelination, and neural stem cell (NSC) proliferation and differentiation. Our findings show that polySia–NCAM is expressed on NSC isolated from adult guinea pig spiral ganglion (GPSG), and in neurons and Schwann cells after differentiation of the NSC with epidermal, glia, fibroblast growth factors (GFs) and neurotrophins. These differentiated cells were immunoreactive with mAb’s to polySia, NCAM, β-III tubulin, nestin, S-100 and stained with BrdU. NSC could regenerate and be differentiated into neurons and Schwann cells. We conclude: (1) polySia is expressed on NSC isolated from adult GPSG and on neurons and Schwann cells differentiated from these NSC; (2) polySia is expressed on neurons primarily during the early stage of neuronal development and is expressed on Schwann cells at points of cell–cell contact; (3) polySia is a functional biomarker that modulates neuronal differentiation in inner ear stem cells. These new findings suggest that replacement of defective cells in the inner ear of hearing impaired patients using adult spiral ganglion neurons may offer potential hope to improve the quality of life for patients with auditory dysfunction and impaired hearing disorders.

  6. Soluble Adenylyl Cyclase Is Required for Retinal Ganglion Cell and Photoreceptor Differentiation

    PubMed Central

    Shaw, Peter X.; Fang, Jiahua; Sang, Alan; Wang, Yan; Kapiloff, Michael S.; Goldberg, Jeffrey L.

    2016-01-01

    Purpose We have previously demonstrated that soluble adenylyl cyclase (sAC) is necessary for retinal ganglion cell (RGC) survival and axon growth. Here, we further investigate the role of sAC in neuronal differentiation during retinal development. Methods Chx10 or Math5 promoter-driven Cre-Lox recombination were used to conditionally delete sAC from early and intermediate retinal progenitor cells during retinal development. We examined cell type–specific markers expressed by retinal cells to estimate their relative numbers and characterize retinal laminar morphology by immunofluorescence in adult and newborn mice. Results Retinal ganglion cell and amacrine cell markers were significantly lower in the retinas of adult Math5cre/sACfl/fl and Chx10cre/sACfl/fl mice than in those of wild-type controls. The effect on RGC development was detectable as early as postnatal day 1 and deleting sAC in either Math5- or Chx10-expressing retinal progenitor cells also reduced nerve fiber layer thickness into adulthood. The thickness of the photoreceptor layer was slightly but statistically significantly decreased in both the newborn Chx10cre/sACfl/fl and Math5cre/sACfl/fl mice, but this reduction and abnormal morphology persisted in the adults in only the Chx10cre/sACfl/fl mice. Conclusions sAC plays an important role in the early retinal development of RGCs as well as in the development of amacrine cells and to a lesser degree photoreceptors. PMID:27679853

  7. 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

  8. 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

  9. DERF: distinctive efficient robust features from the biological modeling of the P ganglion cells.

    PubMed

    Weng, Dawei; Wang, Yunhong; Gong, Mingming; Tao, Dacheng; Wei, Hui; Huang, Di

    2015-08-01

    Studies in neuroscience and biological vision have shown that the human retina has strong computational power, and its information representation supports vision tasks on both ventral and dorsal pathways. In this paper, a new local image descriptor, termed distinctive efficient robust features (DERF), is derived by modeling the response and distribution properties of the parvocellular-projecting ganglion cells in the primate retina. DERF features exponential scale distribution, exponential grid structure, and circularly symmetric function difference of Gaussian (DoG) used as a convolution kernel, all of which are consistent with the characteristics of the ganglion cell array found in neurophysiology, anatomy, and biophysics. In addition, a new explanation for local descriptor design is presented from the perspective of wavelet tight frames. DoG is naturally a wavelet, and the structure of the grid points array in our descriptor is closely related to the spatial sampling of wavelets. The DoG wavelet itself forms a frame, and when we modulate the parameters of our descriptor to make the frame tighter, the performance of the DERF descriptor improves accordingly. This is verified by designing a tight frame DoG, which leads to much better performance. Extensive experiments conducted in the image matching task on the multiview stereo correspondence data set demonstrate that DERF outperforms state of the art methods for both hand-crafted and learned descriptors, while remaining robust and being much faster to compute.

  10. Retinal nerve fiber layer and ganglion cell layer thickness in patients receiving systemic isotretinoin therapy.

    PubMed

    Sekeryapan, Berrak; Dılek, Nursel; Oner, Veysi; Turkyılmaz, Kemal; Aslan, Mehmet Gokhan

    2013-10-01

    To evaluate the effect of oral isotretinoin therapy on retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness by spectral domain optical coherence tomography (OCT). This prospective study included newly diagnosed nodulocystic acne patients about to receive isotretinoin treatment. Macular average GCL thickness and peripapillary average, temporal, nasal, inferior, and superior quadrant RNFL thickness were measured by OCT before and after isotretinoin treatment. Pre- and post-treatment measurements were compared with paired t test. Fifty-six eyes of 28 patients were included. The mean duration of the treatment was 6.5 ± 1.3 months. The mean average GCL thickness was 90.04 ± 5.87 (80-96) μm at baseline and 90.75 ± 6.34 (81-96) μm after treatment. The mean average RNFL thickness was 93.25 ± 6.06 μm (84-107) before treatment and 93.05 ± 5.54 μm (82-106) after treatment. There were no statistically significant differences between pre- and post-treatment values (all p > 0.05). A 6-month course of systemic isotretinoin therapy seems to have no unfavorable effect on retinal ganglion cells; however, larger studies with longer follow-up periods are needed to be conclusive.

  11. 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

  12. [Exclusive radiotherapy for a facial basal cell carcinoma with trigeminal ganglion involvement].

    PubMed

    Longeac, M; Lapeyre, M; Delbet Dupas, C; Barthélémy, I; Pham Dang, N

    2016-06-01

    Basal cell carcinomas with symptomatic perineural invasion are rare entities. We report the case of a 60year-old man (with a grafted kidney), surgically treated in 2007 for a sclerodermiform basal cell carcinoma infiltrating the left nostril. Five years later, a painful left hemifacial hypoesthesia associated with an ulcus rodens of the nasolabial fold appeared. A biopsy confirmed a recurrence. MRI showed an enhancement of the trigeminal ganglion. The patient had a trigeminal perineural invasion secondary to a cutaneous basal cell carcinoma. He received a local intensity-modulated radiotherapy alone (70Gy in 33 sessions), administered from the skin tumour to the skull base. Three years after the end of treatment, the patient is in radiological and clinical remission, with partial recovery of the hypoesthesia. Evolution was marked by iterative corneal ulcers and decreased visual acuity. Modalities of treatment by surgery and/or radiation therapy and complications are poorly described in the literature. PMID:27105681

  13. Enhanced antioxidant and protective activities on retinal ganglion cells of carotenoids-overexpressing transgenic carrot.

    PubMed

    Yoon, Kee Dong; Kang, Suk-Nam; Bae, Ji-Yeong; Lee, Haeng-Soon; Kwak, Sang-Soo; Jang, Insurk; Kim, Il-Suk; Lee, Cheol Ho; Bae, Jung Myung; Lee, Shin Woo; Ahn, Mi-Jeong

    2013-08-01

    Carotenoids are considered to act as antioxidants and protect humans from serious disorders such as skin degeneration and ageing, cardiovascular disease, certain types of cancer, and age-related diseases of the eye. In this study, these chemopreventive activities of a carotenoids-overexpressing transgenic carrot were evaluated. The results of DPPH, hydroxyl, and superoxide radical scavenging tests demonstrate that the acetone extract obtained from the taproots of the carrot plants exhibits significant antioxidant activity. A higher activity was detected in the transgenic carrot extract compared with the wild-type extract. A chemopreventive activity test for degenerative diseases of the eye revealed that pretreatment with the carrot extract reduced cell death in a retinal ganglion cell line, RGC-5 cells exposed to 1-buthionine- (R,S)-sulfoximine and L-glutamic acid.

  14. Visual responses of ganglion cells of a New-World primate, the capuchin monkey, Cebus apella.

    PubMed

    Lee, B B; Silveira, L C; Yamada, E S; Hunt, D M; Kremers, J; Martin, P R; Troy, J B; da Silva-Filho, M

    2000-11-01

    1. The genetic basis of colour vision in New-World primates differs from that in humans and other Old-World primates. Most New-World primate species show a polymorphism; all males are dichromats and most females trichromats. 2. In the retina of Old-World primates such as the macaque, the physiological correlates of trichromacy are well established. Comparison of the retinae in New- and Old-World species may help constrain hypotheses as to the evolution of colour vision and the pathways associated with it. 3. Ganglion cell behaviour was recorded from trichromatic and dichromatic members of a New-World species (the capuchin monkey, Cebus apella) and compared with macaque data. Despite some differences in quantitative detail (such as a temporal response extended to higher frequencies), results from trichromatic animals strongly resembled those from the macaque. 4. In particular, cells of the parvocellular (PC) pathway showed characteristic frequency-dependent changes in responsivity to luminance and chromatic modulation, cells of the magnocellular (MC) pathway showed frequency-doubled responses to chromatic modulation, and the surround of MC cells received a chromatic input revealed on changing the phase of heterochromatically modulated lights. 5. Ganglion cells of dichromats were colour-blind versions of those of trichromats. 6. This strong physiological homology is consistent with a common origin of trichromacy in New- and Old-World monkeys; in the New-World primate the presence of two pigments in the middle-to-long wavelength range permits full expression of the retinal mechanisms of trichromatic vision. PMID:11432364

  15. Eye Histology and Ganglion Cell Topography of Northern Elephant Seals (Mirounga angustirostris).

    PubMed

    Smodlaka, Hrvoje; Khamas, Wael A; Palmer, Lauren; Lui, Bryan; Borovac, Josip A; Cohn, Brian A; Schmitz, Lars

    2016-06-01

    Northern elephant seals are one of the deepest diving marine mammals. As northern elephant seals often reach the bathypelagic zone, it is usually assumed that their eyes possess evolutionary adaptations that provide better ability to see in dim or scotopic environments. The purpose of this study was to carefully describe anatomical and histological traits of the eye that may improve light sensitivity. Northern elephant seals have large, somewhat elliptical eyes, with equatorial and anteroposterior diameters of 5.03 and 4.4 cm, respectively. The cornea is large in diameter and the lens is completely spherical. The iris has pronounced constrictor and dilator muscles, whereas the ciliary muscle is notably less developed. The tapetum lucidum is more prominent than in other pinnipeds, making up about 63% of retinal thickness in the posterior aspect of the globe. Within the retina, the pigmented epithelium lacks pigment except for the region close to the ora serrata. Parts of the photoreceptor and outer nuclear layers are folded. Although the photoreceptor layer is composed predominantly of rods, cone photoreceptors were also observed. Cells within the retinal ganglion cell layer are arranged in a single level. Ganglion cells reach their maximum density (∼1,300 cells per mm(2) ) dorsal to the optic disc, whereas the periphery of the retina is sparsely populated (<100 cells per mm(2) ). All above mentioned features are consistent with the predicted evolutionary adaptations to the photic environment of the bathypelagic zone. Anat Rec, 299:798-805, 2016. © 2016 Wiley Periodicals, Inc. PMID:26950409

  16. 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

  17. Role of HDACs in optic nerve damage-induced nuclear atrophy of retinal ganglion cells.

    PubMed

    Schmitt, Heather M; Schlamp, Cassandra L; Nickells, Robert W

    2016-06-20

    Optic neuropathies are characterized by retinal ganglion cell (RGC) death, resulting in the loss of vision. In glaucoma, the most common optic neuropathy, RGC death is initiated by axonal damage, and can be modeled by inducing acute axonal trauma through procedures such as optic nerve crush (ONC) or optic nerve axotomy. One of the early events of RGC death is nuclear atrophy, and is comprised of RGC-specific gene silencing, histone deacetylation, heterochromatin formation, and nuclear shrinkage. These early events appear to be principally regulated by epigenetic mechanisms involving histone deacetylation. Class I histone deacetylases HDACs 1, 2, and 3 are known to play important roles in the process of early nuclear atrophy in RGCs, and studies using both inhibitors and genetic ablation of Hdacs also reveal a critical role in the cell death process. Select inhibitors, such as those being developed for cancer therapy, may also provide a viable secondary treatment option for optic neuropathies.

  18. Protective effect of Lycium barbarum polysaccharide on retinal ganglion cells in vitro

    PubMed Central

    Yang, Min; Gao, Na; Zhao, Ying; Liu, Li-Xia; Lu, Xue-Jing

    2011-01-01

    AIM To observe the effect of Lycium barbarum polysaccharide (LBP) on rat retinal ganglion cells (RGCs) in vitro. METHODS Retinal cells of neonatal Sprague-Dawley rats were collected 1 to 3 days after birth, and co-cultured with different concentrations of LBP for 24 hours. Absorbance values (OD) were recorded using MTT assay for calculating survival rates. RESULTS All the test groups had protective effects on RGCs. The group with 10mg/mL concentration of LBP had the most significantly difference of OD value compared with that in control group (P<0.01). CONCLUSION LBP can increase the survival rate and promote the growth of mixed cultured rat RGCs. PMID:22553684

  19. A Self-Assembling Injectable Biomimetic Microenvironment Encourages Retinal Ganglion Cell Axon Extension in Vitro.

    PubMed

    Laughter, Melissa R; Ammar, David A; Bardill, James R; Pena, Brisa; Kahook, Malik Y; Lee, David J; Park, Daewon

    2016-08-17

    Sensory-somatic nervous system neurons, such as retinal ganglion cells (RGCs), are typically thought to be incapable of regenerating. However, it is now known that these cells may be stimulated to regenerate by providing them with a growth permissive environment. We have engineered an injectable microenvironment designed to provide growth-stimulating cues for RGC culture. Upon gelation, this injectable material not only self-assembles into laminar sheets, similar to retinal organization, but also possesses a storage modulus comparable to that of retinal tissue. Primary rat RGCs were grown, stained, and imaged in this three-dimensional scaffold. We were able to show that RGCs grown in this retina-like structure exhibited characteristic long, prominent axons. In addition, RGCs showed a consistent increase in average axon length and neurite-bearing ratio over the 7 day culture period, indicating this scaffold is capable of supporting substantial RGC axon extension. PMID:27434231

  20. Melanopsin retinal ganglion cell loss and circadian dysfunction in Alzheimer's disease (Review)

    PubMed Central

    FENG, RUIQI; LI, LIJUAN; YU, HAIYAN; LIU, MIN; ZHAO, WEI

    2016-01-01

    Alzheimer's disease affects 27 million individuals and is the most common cause of dementia worldwide. The pathology of Alzheimer's disease is primarily due to the β-amyloid deposits and neurofibrillary tangles. These deposits exist largely in the cerebral blood vessels, but have also been shown to exist in retinal vessels. A new class of cells that were recently identified, known as melanopsin-expressing retinal ganglion cells (mRGCs), are involved in the non-image forming functions of the eye. These functions include circadian activities such as temperature rhythms, melatonin release and rest-activity cycles. Circadian dysfunction has been investigated in many cases of Alzheimer's disease. In this review, we outline the current accepted Alzheimer's disease pathology, the role of mRCGs in optic neuropathies and the role of mRCGs, leading to circadian dysfunction, in Alzheimer's disease. PMID:26935586

  1. Atoh7 promotes the differentiation of Müller cells-derived retinal stem cells into retinal ganglion cells in a rat model of glaucoma

    PubMed Central

    Song, Wei-tao; Zhang, Xue-yong

    2015-01-01

    Glaucoma is one of the leading eye diseases resulting in blindness due to the death of retinal ganglion cells. This study aimed to develop novel protocol to promote the differentiation of retinal Müller cells into ganglion cells in vivo in a rat model of glaucoma. The stem cells dedifferentiated from rat retinal Müller cells were randomized to receive transfection with empty lentivirus PGC-FU-GFP or lentivirus PGC-FU-Atoh7-GFP, or no transfection. The stem cells were induced further to differentiate. Ocular hypertension was induced using laser photocoagulation. The eyes were injected with Atoh7 expression vector lentivirus PGC-FU-Atoh7-GFP. Eyeball frozen sections, immunohistochemistry, RT-PCR, Western bolt, and apoptosis assay were performed. We found that the proportion of ganglion cells differentiated from Atoh7-tranfected stem cells was significantly higher than that of the other two groups. The mean intraocular pressure of glaucomatous eyes was elevated significantly compared with those of contralateral eyes. Some retinal Müller cells in the inner nuclear layer entered the mitotic cell cycle in rat chronic ocular hypertension glaucoma model. Atoh7 contributes to the differentiation of retinal Müller cells into retinal ganglion cells in rat model of glaucoma. In conclusion, Atoh7 promotes the differentiation of Müller cells-derived retinal stem cells into retinal ganglion cells in a rat model of glaucoma, thus opening up a new avenue for gene therapy and optic nerve regeneration in glaucoma. PMID:25710928

  2. Nonlinear spatial integration in the receptive field surround of retinal ganglion cells.

    PubMed

    Takeshita, Daisuke; Gollisch, Tim

    2014-05-28

    Throughout different sensory systems, individual neurons integrate incoming signals over their receptive fields. The characteristics of this signal integration are crucial determinants for the neurons' functions. For ganglion cells in the vertebrate retina, receptive fields are characterized by the well-known center-surround structure and, although several studies have addressed spatial integration in the receptive field center, little is known about how visual signals are integrated in the surround. Therefore, we set out here to characterize signal integration and to identify relevant nonlinearities in the receptive field surround of ganglion cells in the isolated salamander retina by recording spiking activity with extracellular electrodes under visual stimulation of the center and surround. To quantify nonlinearities of spatial integration independently of subsequent nonlinearities of spike generation, we applied the technique of iso-response measurements as follows: using closed-loop experiments, we searched for different stimulus patterns in the surround that all reduced the center-evoked spiking activity by the same amount. The identified iso-response stimuli revealed strongly nonlinear spatial integration in the receptive field surrounds of all recorded cells. Furthermore, cell types that had been shown previously to have different nonlinearities in receptive field centers showed similar surround nonlinearities but differed systematically in the adaptive characteristics of the surround. Finally, we found that there is an optimal spatial scale of surround suppression; suppression was most effective when surround stimulation was organized into subregions of several hundred micrometers in diameter, indicating that the surround is composed of subunits that have strong center-surround organization themselves. PMID:24872559

  3. Melanopsin‐expressing ganglion cells on macaque and human retinas form two morphologically distinct populations

    PubMed Central

    Liao, Hsi‐Wen; Ren, Xiaozhi; Peterson, Beth B.; Marshak, David W.; Yau, King‐Wai; Gamlin, Paul D.

    2016-01-01

    ABSTRACT The long‐term goal of this research is to understand how retinal ganglion cells that express the photopigment melanopsin, also known as OPN4, contribute to vision in humans and other primates. Here we report the results of anatomical studies using our polyclonal antibody specifically against human melanopsin that confirm and extend previous descriptions of melanopsin cells in primates. In macaque and human retina, two distinct populations of melanopsin cells were identified based on dendritic stratification in either the inner or the outer portion of the inner plexiform layer (IPL). Variation in dendritic field size and cell density with eccentricity was confirmed, and dendritic spines, a new feature of melanopsin cells, were described. The spines were the sites of input from DB6 diffuse bipolar cell axon terminals to the inner stratifying type of melanopsin cells. The outer stratifying melanopsin type received inputs from DB6 bipolar cells via a sparse outer axonal arbor. Outer stratifying melanopsin cells also received inputs from axon terminals of dopaminergic amacrine cells. On the outer stratifying melanopsin cells, ribbon synapses from bipolar cells and conventional synapses from amacrine cells were identified in electron microscopic immunolabeling experiments. Both inner and outer stratifying melanopsin cell types were retrogradely labeled following tracer injection in the lateral geniculate nucleus (LGN). In addition, a method for targeting melanopsin cells for intracellular injection using their intrinsic fluorescence was developed. This technique was used to demonstrate that melanopsin cells were tracer coupled to amacrine cells and would be applicable to electrophysiological experiments in the future. J. Comp. Neurol. 524:2845–2872, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26972791

  4. Melanopsin-expressing ganglion cells on macaque and human retinas form two morphologically distinct populations.

    PubMed

    Liao, Hsi-Wen; Ren, Xiaozhi; Peterson, Beth B; Marshak, David W; Yau, King-Wai; Gamlin, Paul D; Dacey, Dennis M

    2016-10-01

    The long-term goal of this research is to understand how retinal ganglion cells that express the photopigment melanopsin, also known as OPN4, contribute to vision in humans and other primates. Here we report the results of anatomical studies using our polyclonal antibody specifically against human melanopsin that confirm and extend previous descriptions of melanopsin cells in primates. In macaque and human retina, two distinct populations of melanopsin cells were identified based on dendritic stratification in either the inner or the outer portion of the inner plexiform layer (IPL). Variation in dendritic field size and cell density with eccentricity was confirmed, and dendritic spines, a new feature of melanopsin cells, were described. The spines were the sites of input from DB6 diffuse bipolar cell axon terminals to the inner stratifying type of melanopsin cells. The outer stratifying melanopsin type received inputs from DB6 bipolar cells via a sparse outer axonal arbor. Outer stratifying melanopsin cells also received inputs from axon terminals of dopaminergic amacrine cells. On the outer stratifying melanopsin cells, ribbon synapses from bipolar cells and conventional synapses from amacrine cells were identified in electron microscopic immunolabeling experiments. Both inner and outer stratifying melanopsin cell types were retrogradely labeled following tracer injection in the lateral geniculate nucleus (LGN). In addition, a method for targeting melanopsin cells for intracellular injection using their intrinsic fluorescence was developed. This technique was used to demonstrate that melanopsin cells were tracer coupled to amacrine cells and would be applicable to electrophysiological experiments in the future. J. Comp. Neurol. 524:2845-2872, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26972791

  5. Retinal ganglion cells projecting to the accessory optic system in optokinetic blind albinotic rats are direction-selective.

    PubMed

    Krause, Martin; Distler, Claudia; Hoffmann, Klaus-Peter

    2014-07-01

    The optokinetic deficits in albinotic rats and ferrets are caused by the loss of direction selectivity in the accessory optic system (AOS). However, the underlying mechanisms for this loss are still not clear. Here we tested the hypothesis that, in albino rats, the retinal input to the AOS lacks direction selectivity and, as a consequence, neurons in the AOS are direction non-selective. We investigated ON-center direction-selective retinal ganglion cells, the major input to the AOS, in pigmented Long Evans and albino Wistar rats using extracellular in vitro patch-clamp techniques. To visualise putative AOS-projecting direction-selective ganglion cells, we retrogradely labeled them by injection of the infrared-sensitive dye indocyanine green into the medial terminal nucleus of the AOS. The present study is the first to present physiological evidence for retinal ON-center direction-selective ganglion cells in rat. Our results show that, in albinotic and pigmented rats, ON-center retinal ganglion cells projecting to the AOS are similarly direction-selective, suggesting that the optokinetic deficit must be caused by the abolition of direction selectivity in the AOS itself. PMID:24698401

  6. Rhythmic Ganglion Cell Activity in Bleached and Blind Adult Mouse Retinas

    PubMed Central

    Menzler, Jacob; Channappa, Lakshmi; Zeck, Guenther

    2014-01-01

    In retinitis pigmentosa – a degenerative disease which often leads to incurable blindness- the loss of photoreceptors deprives the retina from a continuous excitatory input, the so-called dark current. In rodent models of this disease this deprivation leads to oscillatory electrical activity in the remaining circuitry, which is reflected in the rhythmic spiking of retinal ganglion cells (RGCs). It remained unclear, however, if the rhythmic RGC activity is attributed to circuit alterations occurring during photoreceptor degeneration or if rhythmic activity is an intrinsic property of healthy retinal circuitry which is masked by the photoreceptor’s dark current. Here we tested these hypotheses by inducing and analysing oscillatory activity in adult healthy (C57/Bl6) and blind mouse retinas (rd10 and rd1). Rhythmic RGC activity in healthy retinas was detected upon partial photoreceptor bleaching using an extracellular high-density multi-transistor-array. The mean fundamental spiking frequency in bleached retinas was 4.3 Hz; close to the RGC rhythm detected in blind rd10 mouse retinas (6.5 Hz). Crosscorrelation analysis of neighbouring wild-type and rd10 RGCs (separation distance <200 µm) reveals synchrony among homologous RGC types and a constant phase shift (∼70 msec) among heterologous cell types (ON versus OFF). The rhythmic RGC spiking in these retinas is driven by a network of presynaptic neurons. The inhibition of glutamatergic ganglion cell input or the inhibition of gap junctional coupling abolished the rhythmic pattern. In rd10 and rd1 retinas the presynaptic network leads to local field potentials, whereas in bleached retinas additional pharmacological disinhibition is required to achieve detectable field potentials. Our results demonstrate that photoreceptor bleaching unmasks oscillatory activity in healthy retinas which shares many features with the functional phenotype detected in rd10 retinas. The quantitative physiological differences advance the

  7. 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

  8. Responses of macaque ganglion cells to the relative phase of heterochromatically modulated lights.

    PubMed Central

    Smith, V C; Lee, B B; Pokorny, J; Martin, P R; Valberg, A

    1992-01-01

    1. We measured the response of macaque ganglion cells to sinusoidally modulated red and green lights as the relative phase, theta, of the lights was varied. 2. At low frequencies, red-green ganglion cells of the parvocellular (PC-) pathway with opponent inputs from middle-wavelength sensitive (M-) and long-wavelength sensitive (L-) cones were minimally sensitive to luminance modulation (theta = 0 deg) and maximally sensitive to chromatic modulation (theta = 180 deg). With increasing frequency, the phase, theta, of minimal amplitude gradually changed, in opposite directions for cells with M- and L-cone centres. 3. At high frequencies (at and above 20 Hz), phasic cells of the magnocellular (MC-) pathway were maximally responsive when theta approximately 0 deg and minimally responsive when theta approximately 180 deg, as expected from an achromatic mechanism. At lower frequencies, the phase of minimal response shifted, for both on- and off-centre cells, to values of theta intermediate between 0 and 180 deg. This phase asymmetry was absent if the centre alone was stimulated with a small field. 4. For PC-pathway cells, it was possible to provide an account of response phase as a function of theta, using a model involving three parameters; phases of the L- and M-cone mechanisms and a L/M cone weighting term. For red-green cells, the phase parameters were monotonically related to temporal frequency and revealed a centre-surround phase difference. The phase difference was linear with a slope of 1-3 deg Hz-1. If this represents a latency difference, it would be 3-8 ms. Otherwise, temporal properties of the M- and L-cones appeared similar if not identical. By addition of a scaling term, the model could be extended to give an adequate account of the amplitude of responses. 5. We were able to activate selectively the surrounds of cells with short-wavelength (S-) cone input to their centres, and so were able to assess L/M cone weighting to the surround. M- and L-cone inputs

  9. Imaging Light Responses of Foveal Ganglion Cells in the Living Macaque Eye

    PubMed Central

    Masella, Benjamin; Dalkara, Deniz; Zhang, Jie; Flannery, John. G.; Schaffer, David V.; Williams, David R.

    2014-01-01

    The fovea dominates primate vision, and its anatomy and perceptual abilities are well studied, but its physiology has been little explored because of limitations of current physiological methods. In this study, we adapted a novel in vivo imaging method, originally developed in mouse retina, to explore foveal physiology in the macaque, which permits the repeated imaging of the functional response of many retinal ganglion cells (RGCs) simultaneously. A genetically encoded calcium indicator, G-CaMP5, was inserted into foveal RGCs, followed by calcium imaging of the displacement of foveal RGCs from their receptive fields, and their intensity-response functions. The spatial offset of foveal RGCs from their cone inputs makes this method especially appropriate for fovea by permitting imaging of RGC responses without excessive light adaptation of cones. This new method will permit the tracking of visual development, progression of retinal disease, or therapeutic interventions, such as insertion of visual prostheses. PMID:24806684

  10. NMDA Receptors Multiplicatively Scale Visual Signals and Enhance Directional Motion Discrimination in Retinal Ganglion Cells.

    PubMed

    Poleg-Polsky, Alon; Diamond, Jeffrey S

    2016-03-16

    Postsynaptic responses in many CNS neurons are typically small and variable, often making it difficult to distinguish physiologically relevant signals from background noise. To extract salient information, neurons are thought to integrate multiple synaptic inputs and/or selectively amplify specific synaptic activation patterns. Here, we present evidence for a third strategy: directionally selective ganglion cells (DSGCs) in the mouse retina multiplicatively scale visual signals via a mechanism that requires both nonlinear NMDA receptor (NMDAR) conductances in DSGC dendrites and directionally tuned inhibition provided by the upstream retinal circuitry. Postsynaptic multiplication enables DSGCs to discriminate visual motion more accurately in noisy visual conditions without compromising directional tuning. These findings demonstrate a novel role for NMDARs in synaptic processing and provide new insights into how synaptic and network features interact to accomplish physiologically relevant neural computations. PMID:26948896

  11. 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.

  12. Cobalamin C Deficiency Shows a Rapidly Progressing Maculopathy With Severe Photoreceptor and Ganglion Cell Loss

    PubMed Central

    Bonafede, Lucas; Ficicioglu, Can H.; Serrano, Leona; Han, Grace; Morgan, Jessica I. W.; Mills, Monte D.; Forbes, Brian J.; Davidson, Stefanie L.; Binenbaum, Gil; Kaplan, Paige B.; Nichols, Charles W.; Verloo, Patrick; Leroy, Bart P.; Maguire, Albert M.; Aleman, Tomas S.

    2015-01-01

    Purpose To describe in detail the retinal structure and function of a group of patients with cobalamin C (cblC) disease. Methods Patients (n = 11, age 4 months to 15 years) with cblC disease (9/11, early onset) diagnosed by newborn screening underwent complete ophthalmic examinations, fundus photography, near-infrared reflectance imaging, and spectral-domain optical coherence tomography (SD-OCT). Electroretinograms (ERGs) were performed in a subset of patients. Results Patients carried homozygous or compound heterozygote mutations in the methylmalonic aciduria and homocystinuria type C (MMACHC) gene. Late-onset patients had a normal exam. All early-onset patients showed a maculopathy; older subjects had a retina-wide degeneration (n = 4; >7 years of age). In general, retinal changes were first observed before 1 year of age and progressed within months to a well-established maculopathy. Pseudocolobomas were documented in three patients. Measurable visual acuities ranged from 20/200 to 20/540. Nystagmus was present in 8/11 patients; 5/6 patients had normal ERGs; 1/6 had reduced rod-mediated responses. Spectral-domain OCT showed macular thinning, with severe ganglion cell layer (GCL) and outer nuclear layer (ONL) loss. Inner retinal thickening was observed in areas of total GCL/ONL loss. A normal lamination pattern in the peripapillary nasal retina was often seen despite severe central and/or retina-wide disease. Conclusions Patients with early-onset cblC and MMACHC mutations showed an early-onset, unusually fast-progressing maculopathy with severe central ONL and GCL loss. An abnormally thickened inner retina supports a remodeling response to both photoreceptor and ganglion cell degeneration and/or an interference with normal development in early-onset cblC. PMID:26658511

  13. Modeling the impact of common noise inputs on the network activity of retinal ganglion cells

    PubMed Central

    Ahmadian, Yashar; Shlens, Jonathon; Pillow, Jonathan W.; Kulkarni, Jayant; Litke, Alan M.; Chichilnisky, E. J.; Simoncelli, Eero; Paninski, Liam

    2013-01-01

    Synchronized spontaneous firing among retinal ganglion cells (RGCs), on timescales faster than visual responses, has been reported in many studies. Two candidate mechanisms of synchronized firing include direct coupling and shared noisy inputs. In neighboring parasol cells of primate retina, which exhibit rapid synchronized firing that has been studied extensively, recent experimental work indicates that direct electrical or synaptic coupling is weak, but shared synaptic input in the absence of modulated stimuli is strong. However, previous modeling efforts have not accounted for this aspect of firing in the parasol cell population. Here we develop a new model that incorporates the effects of common noise, and apply it to analyze the light responses and synchronized firing of a large, densely-sampled network of over 250 simultaneously recorded parasol cells. We use a generalized linear model in which the spike rate in each cell is determined by the linear combination of the spatio-temporally filtered visual input, the temporally filtered prior spikes of that cell, and unobserved sources representing common noise. The model accurately captures the statistical structure of the spike trains and the encoding of the visual stimulus, without the direct coupling assumption present in previous modeling work. Finally, we examined the problem of decoding the visual stimulus from the spike train given the estimated parameters. The common-noise model produces Bayesian decoding performance as accurate as that of a model with direct coupling, but with significantly more robustness to spike timing perturbations. PMID:22203465

  14. Modeling the impact of common noise inputs on the network activity of retinal ganglion cells.

    PubMed

    Vidne, Michael; Ahmadian, Yashar; Shlens, Jonathon; Pillow, Jonathan W; Kulkarni, Jayant; Litke, Alan M; Chichilnisky, E J; Simoncelli, Eero; Paninski, Liam

    2012-08-01

    Synchronized spontaneous firing among retinal ganglion cells (RGCs), on timescales faster than visual responses, has been reported in many studies. Two candidate mechanisms of synchronized firing include direct coupling and shared noisy inputs. In neighboring parasol cells of primate retina, which exhibit rapid synchronized firing that has been studied extensively, recent experimental work indicates that direct electrical or synaptic coupling is weak, but shared synaptic input in the absence of modulated stimuli is strong. However, previous modeling efforts have not accounted for this aspect of firing in the parasol cell population. Here we develop a new model that incorporates the effects of common noise, and apply it to analyze the light responses and synchronized firing of a large, densely-sampled network of over 250 simultaneously recorded parasol cells. We use a generalized linear model in which the spike rate in each cell is determined by the linear combination of the spatio-temporally filtered visual input, the temporally filtered prior spikes of that cell, and unobserved sources representing common noise. The model accurately captures the statistical structure of the spike trains and the encoding of the visual stimulus, without the direct coupling assumption present in previous modeling work. Finally, we examined the problem of decoding the visual stimulus from the spike train given the estimated parameters. The common-noise model produces Bayesian decoding performance as accurate as that of a model with direct coupling, but with significantly more robustness to spike timing perturbations.

  15. Focal electrical stimulation of major ganglion cell types in the primate retina for the design of visual prostheses.

    PubMed

    Jepson, Lauren H; Hottowy, Pawel; Mathieson, Keith; Gunning, Deborah E; Dabrowski, Wladyslaw; Litke, Alan M; Chichilnisky, E J

    2013-04-24

    Electrical stimulation of retinal neurons with an advanced retinal prosthesis may eventually provide high-resolution artificial vision to the blind. However, the success of future prostheses depends on the ability to activate the major parallel visual pathways of the human visual system. Electrical stimulation of the five numerically dominant retinal ganglion cell types was investigated by simultaneous stimulation and recording in isolated peripheral primate (Macaca sp.) retina using multi-electrode arrays. ON and OFF midget, ON and OFF parasol, and small bistratified ganglion cells could all be activated directly to fire a single spike with submillisecond latency using brief pulses of current within established safety limits. Thresholds for electrical stimulation were similar in all five cell types. In many cases, a single cell could be specifically activated without activating neighboring cells of the same type or other types. These findings support the feasibility of direct electrical stimulation of the major visual pathways at or near their native spatial and temporal resolution.

  16. NKCC1-Deficiency Results in Abnormal Proliferation of Neural Progenitor Cells of the Lateral Ganglionic Eminence

    PubMed Central

    Magalhães, Ana Cathia; Rivera, Claudio

    2016-01-01

    The proliferative pool of neural progenitor cells is maintained by exquisitely controlled mechanisms for cell cycle regulation. The Na-K-Cl cotransporter (NKCC1) is important for regulating cell volume and the proliferation of different cell types in vitro. NKCC1 is expressed in ventral telencephalon of embryonic brains suggesting a potential role in neural development of this region. The ventral telencephalon is a major source for both interneuron and oligodendrocyte precursor cells. Whether NKCC1 is involved in the proliferation of these cell populations remains unknown. In order to assess this question, we monitored several markers for neural, neuronal, and proliferating cells in wild-type (WT) and NKCC1 knockout (KO) mouse brains. We found that NKCC1 was expressed in neural progenitor cells from the lateral ganglionic eminence (LGE) at E12.5. Mice lacking NKCC1 expression displayed reduced phospho-Histone H3 (PH3)-labeled mitotic cells in the ventricular zone (VZ) and reduced cell cycle reentry. Accordingly, we found a significant reduction of Sp8-labeled immature interneurons migrating from the dorsal LGE in NKCC1-deficient mice at a later developmental stage. Interestingly, at E14.5, NKCC1 regulated also the formation of Olig2-labeled oligodendrocyte precursor cells. Collectively, these findings show that NKCC1 serves in vivo as a modulator of the cell cycle decision in the developing ventral telencephalon at the early stage of neurogenesis. These results present a novel mechanistic avenue to be considered in the recent proposed involvement of chloride transporters in a number of developmentally related diseases, such as epilepsy, autism, and schizophrenia. PMID:27582690

  17. Photoresponse diversity among the five types of intrinsically photosensitive retinal ganglion cells

    PubMed Central

    Zhao, Xiwu; Stafford, Ben K; Godin, Ashley L; King, W Michael; Wong, Kwoon Y

    2014-01-01

    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. PMID:24396062

  18. 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. PMID:24396062

  19. NKCC1-Deficiency Results in Abnormal Proliferation of Neural Progenitor Cells of the Lateral Ganglionic Eminence.

    PubMed

    Magalhães, Ana Cathia; Rivera, Claudio

    2016-01-01

    The proliferative pool of neural progenitor cells is maintained by exquisitely controlled mechanisms for cell cycle regulation. The Na-K-Cl cotransporter (NKCC1) is important for regulating cell volume and the proliferation of different cell types in vitro. NKCC1 is expressed in ventral telencephalon of embryonic brains suggesting a potential role in neural development of this region. The ventral telencephalon is a major source for both interneuron and oligodendrocyte precursor cells. Whether NKCC1 is involved in the proliferation of these cell populations remains unknown. In order to assess this question, we monitored several markers for neural, neuronal, and proliferating cells in wild-type (WT) and NKCC1 knockout (KO) mouse brains. We found that NKCC1 was expressed in neural progenitor cells from the lateral ganglionic eminence (LGE) at E12.5. Mice lacking NKCC1 expression displayed reduced phospho-Histone H3 (PH3)-labeled mitotic cells in the ventricular zone (VZ) and reduced cell cycle reentry. Accordingly, we found a significant reduction of Sp8-labeled immature interneurons migrating from the dorsal LGE in NKCC1-deficient mice at a later developmental stage. Interestingly, at E14.5, NKCC1 regulated also the formation of Olig2-labeled oligodendrocyte precursor cells. Collectively, these findings show that NKCC1 serves in vivo as a modulator of the cell cycle decision in the developing ventral telencephalon at the early stage of neurogenesis. These results present a novel mechanistic avenue to be considered in the recent proposed involvement of chloride transporters in a number of developmentally related diseases, such as epilepsy, autism, and schizophrenia. PMID:27582690

  20. Temporal response of ganglion cells of the macaque retina to cone-specific modulation

    NASA Astrophysics Data System (ADS)

    Yeh, T.; Lee, B. B.; Kremers, J.

    1995-03-01

    The temporal response of cone inputs to macaque retinal ganglion cells were compared with cone-specific sinusoidal modulation used to isolate each cone type. For all cell types of the parvocellular (PC) pathway, temporal responsivity was similar for short (S)-, middle (M)-, and long (L)-wavelength-sensitive cone inputs, apart from small latency differences between inputs to center and surround. The temporal response resembled that expected from receptor physiology. Responses of cells of the magnocellular pathway to M- or L-cone modulation showed more complex properties indicative of postreceptoral processing. Human psychophysical temporal-sensitivity functions were acquired with S-cone modulation under conditions similar to those for the physiological measurements. Ratios of psychophysical to physiological data from S-cone cells (the only cells that respond to this stimulus) yielded an estimate of the central filter acting upon PC-pathway signals. The filter characteristic could be described by a four-stage low-pass filter with corner frequency 3-5 Hz.

  1. 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.

  2. Exogenous glycosaminoglycans induce complete inversion of retinal ganglion cell bodies and their axons within the retinal neuroepithelium.

    PubMed Central

    Brittis, P A; Silver, J

    1994-01-01

    Prior to forming an axon, retinal ganglion cells retain a primitive radial configuration while maintaining ventricular and vitreal endfeet attachments. During their subsequent differentiation, ganglion cells polarize their cell body and axon only along the vitreal surface. When the ventricular surfaces of intact retinas in organ culture were exposed to free chondroitin sulfate (CS) in solution, both the cell body and nerve fiber layers were repolarized to the opposite side of the neuroepithelium. However, the basal lamina remained in its usual position. Thus, the ability to initiate an axon is not restricted to the vitreal endfoot region of differentiating neurons, and in addition, the radial position at which the axon emerges can be mediated by the location and concentration of the extracellular CS milieu. Images PMID:8052616

  3. 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

  4. Modulation of voltage-gated Ca2+ channels in rat retinal ganglion cells by gabapentin.

    PubMed

    Farrell, Spring R; Sargoy, Allison; Brecha, Nicholas C; Barnes, Steven

    2014-01-01

    The α2δ auxiliary subunits of voltage-gated Ca2+ channels (VGCCs) are important modulators of VGCC function. Gabapentin interacts with α2δ1 and α2δ2 subunits and is reported to reduce Ca2+ channel current amplitude (ICa). This study aimed to determine the effects of gabapentin on VGCCs in retinal ganglion cells (RGCs). Whole cell patch clamp was used to record ICa in isolated RGCs, and calcium imaging was used to measure Ca2+ transients from RGCs in situ. Immunohistochemistry was used to detect the presence of α2δ1-containing VGCCs in isolated RGCs in the absence and presence of gabapentin pretreatment. Acute administration of gabapentin reduced ICa and Ca2+ transients compared to control conditions. In isolated RGCs, pretreatment with gabapentin (4-18 h) reduced ICa, and cell surface α2δ1 staining was reduced compared to nonpretreated cells. Acute administration of gabapentin to isolated RGCs that had been pretreated further reduced ICa. These results show that gabapentin has both short-term and long-term mechanisms to reduce ICa in isolated RGCs. Some Ca2+ channel blockers have been shown to protect RGCs in retinal trauma suggesting that modulation of VGCCs by gabapentin may prevent the deleterious effects of elevated Ca2+ levels in RGCs in trauma and disease.

  5. Two types of ON direction-selective ganglion cells in rabbit retina.

    PubMed

    Kanjhan, Refik; Sivyer, Benjamin

    2010-10-11

    Direction-selective ganglion cells (DSGCs) respond with robust spiking to image motion in a particular direction. Previously, two main types of DSGCs have been described in rabbit retina: the ON-OFF DSGCs respond to both increases and decreases in illumination, whereas the ON DSGCs respond only to increases in illumination. In this study, we show that there are two distinct types of ON DSGCs, which can be separated by differences in their receptive-field properties, dendritic morphology and tracer-coupling pattern. While both types show robust direction-selectivity, one type responds to increases in illumination with sustained firing, whereas the other responds with relatively transient firing. The two types of ON DSGCs also have distinct dendritic morphologies: the sustained cells give rise to shorter and more numerous terminal dendrites, which are distributed throughout the dendritic field forming a space-filling lattice. In addition, the transient ON DSGCs, but not the sustained ON DSGCs, show tracer-coupling to a mosaic of amacrine cells when filled with Neurobiotin. Both types of ON DSGCs have been encountered in previous studies but were not recognized as distinct types. We propose that the two types also differ in their central projections, with only the sustained cells projecting to the medial terminal nucleus (MTN) of the accessory optic system (AOS).

  6. Math5 is required for retinal ganglion cell and optic nerve formation

    PubMed Central

    Brown, Nadean L.; Patel, Sima; Brzezinski, Joseph; Glaser, Tom

    2006-01-01

    SUMMARY The vertebrate retina contains seven major neuronal and glial cell types in an interconnected network that collects, processes and sends visual signals through the optic nerve to the brain. Retinal neuron differentiation is thought to require both intrinsic and extrinsic factors, yet few intrinsic gene products have been identified that direct this process. Math5 (Atoh7) encodes a basic helix-loop-helix (bHLH) transcription factor that is specifically expressed by mouse retinal progenitors. Math5 is highly homologous to atonal, which is critically required for R8 neuron formation during Drosophila eye development. Like R8 cells in the fly eye, retinal ganglion cells (RGCs) are the first neurons in the vertebrate eye. Here we show that Math5 mutant mice are fully viable, yet lack RGCs and optic nerves. Thus, two evolutionarily diverse eye types require atonal gene family function for the earliest stages of retinal neuron formation. At the same time, the abundance of cone photoreceptors is significantly increased in Math5−/− retinae, suggesting a binary change in cell fate from RGCs to cones. A small number of nascent RGCs are detected during embryogenesis, but these fail to develop further, suggesting that committed RGCs may also require Math5 function. PMID:11493566

  7. Effect of protons on the inward current evoked by capsaicin in isolated dorsal root ganglion cells.

    PubMed

    Petersen, M; LaMotte, R H

    1993-07-01

    Capsaicin excites a subset of dorsal root ganglion (DRG) neurons by inducing an inward current. We have examined this inward current in response to high concentrations of protons in the external medium. The experiments were done in freshly dissociated DRG cells under whole-cell voltage-clamp conditions. The amplitude of the current evoked by capsaicin (200-300 nM) was increased with increasing concentrations of protons (pH 6.9-6.3). Increasing the acidification of the external medium from a physiological pH of 7.3 to 6.3 enhanced 7-fold the current induced by capsaicin (300 nM). Cells unresponsive to capsaicin in a physiological pH were also unresponsive to capsaicin in an acidic solution. There was a progressive decrease in the amplitude of the capsaicin-evoked current when the drug was repeatedly applied either at a physiological pH or an acidic pH of 6.3. Exposure of the cell to acidic solutions of capsaicin did not subsequently increase an evoked inward current when capsaicin was applied at a physiological pH nor did it lead to an inward current evoked by proton ions where there had been none. Our results suggest that increased proton concentrations in the extracellular medium could play an important modulatory role in the function of chemosensitive sensory neurons.

  8. Macaque retinal ganglion cell responses to visual patterns: harmonic composition, noise, and psychophysical detectability.

    PubMed

    Cooper, Bonnie; Lee, Barry B; Cao, Dingcai

    2016-06-01

    The goal of these experiments was to test how well cell responses to visual patterns can be predicted from the sinewave tuning curve. Magnocellular (MC) and parvocellular (PC) ganglion cell responses to different spatial waveforms (sinewave, squarewave, and ramp waveforms) were measured across a range of spatial frequencies. Sinewave spatial tuning curves were fit with standard Gaussian models. From these fits, waveforms and spatial tuning of a cell's responses to the other waveforms were predicted for different harmonics by scaling in amplitude for the power in the waveform's Fourier expansion series over spatial frequency. Since higher spatial harmonics move at a higher temporal frequency, an additional scaling for each harmonic by the MC (bandpass) or PC (lowpass) temporal response was included, together with response phase. Finally, the model included a rectifying nonlinearity. This provided a largely satisfactory estimation of MC and PC cell responses to complex waveforms. As a consequence of their transient responses, MC responses to complex waveforms were found to have significantly more energy in higher spatial harmonic components than PC responses. Response variance (noise) was also quantified as a function of harmonic component. Noise increased to some degree for the higher harmonics. The data are relevant for psychophysical detection or discrimination of visual patterns, and we discuss the results in this context. PMID:26936977

  9. 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.

  10. 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

  11. Intrinsic Photosensitive Retinal Ganglion Cells in the Diurnal Rodent, Arvicanthis ansorgei

    PubMed Central

    Karnas, Diana; Hicks, David; Mordel, Jérôme; Pévet, Paul; Meissl, Hilmar

    2013-01-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) represent a new class of photoreceptors which support a variety of non-image forming physiological functions, such as circadian photoentrainment, pupillary light reflex and masking responses to light. In view of the recently proposed role of retinal inputs for the regulation of diurnal and nocturnal behavior, we performed the first deep analysis of the ipRGC system in a diurnal rodent model, Arvicanthisansorgei, and compared the anatomical and physiological properties of ipRGCs with those of nocturnal mice. Based on somata location, stratification pattern and melanopsin expression, we identified two main ipRGC types in the retina of Arvicanthis: M1, constituting 74% of all ipRGCs and non-M1 (consisting mainly of the M2 type) constituting the following 25%. The displaced ipRGCs were rarely encountered. Phenotypical staining patterns of ganglion cell markers showed a preferential expression of Brn3 and neurofilaments in non-M1 ipRGCs. In general, the anatomical properties and molecular phenotyping of ipRGCs in Arvicanthis resemble ipRGCs of the mouse retina, however the percentage of M1 cells is considerably higher in the diurnal animal. Multi-electrode array recordings (MEA) identified in newborn retinas of Arvicanthis three response types of ipRGCs (type I, II and III) which are distinguished by their light sensitivity, response strength, latency and duration. Type I ipRGCs exhibited a high sensitivity to short light flashes and showed, contrary to mouse type I ipRGCs, robust light responses to 10 ms flashes. The morphological, molecular and physiological analysis reveals very few differences between mouse and Arvicanthis ipRGCs. These data imply that the influence of retinal inputs in defining the temporal niche could be related to a stronger cone input into ipRGCs in the cone-rich Arvicanthis retina, and to the higher sensitivity of type I ipRGCs and elevated proportion of M1 cells. PMID:23951350

  12. Probing Cell Deformability via Acoustically Actuated Bubbles.

    PubMed

    Xie, Yuliang; Nama, Nitesh; Li, Peng; Mao, Zhangming; Huang, Po-Hsun; Zhao, Chenglong; Costanzo, Francesco; Huang, Tony Jun

    2016-02-17

    An acoustically actuated, bubble-based technique is developed to investigate the deformability of cells suspended in microfluidic devices. A microsized bubble is generated by an optothermal effect near the targeted cells, which are suspended in a microfluidic chamber. Subsequently, acoustic actuation is employed to create localized acoustic streaming. In turn, the streaming flow results in hydrodynamic forces that deform the cells in situ. The deformability of the cells is indicative of their mechanical properties. The method in this study measures mechanical biomarkers from multiple cells in a single experiment, and it can be conveniently integrated with other bioanalysis and drug-screening platforms. Using this technique, the mean deformability of tens of HeLa, HEK, and HUVEC cells is measured to distinguish their mechanical properties. HeLa cells are deformed upon treatment with Cytochalasin. The technique also reveals the deformability of each subpopulation in a mixed, heterogeneous cell sample by the use of both fluorescent markers and mechanical biomarkers. The technique in this study, apart from being relevant to cell biology, will also enable biophysical cellular diagnosis. PMID:26715211

  13. Probing Cell Deformability via Acoustically Actuated Bubbles.

    PubMed

    Xie, Yuliang; Nama, Nitesh; Li, Peng; Mao, Zhangming; Huang, Po-Hsun; Zhao, Chenglong; Costanzo, Francesco; Huang, Tony Jun

    2016-02-17

    An acoustically actuated, bubble-based technique is developed to investigate the deformability of cells suspended in microfluidic devices. A microsized bubble is generated by an optothermal effect near the targeted cells, which are suspended in a microfluidic chamber. Subsequently, acoustic actuation is employed to create localized acoustic streaming. In turn, the streaming flow results in hydrodynamic forces that deform the cells in situ. The deformability of the cells is indicative of their mechanical properties. The method in this study measures mechanical biomarkers from multiple cells in a single experiment, and it can be conveniently integrated with other bioanalysis and drug-screening platforms. Using this technique, the mean deformability of tens of HeLa, HEK, and HUVEC cells is measured to distinguish their mechanical properties. HeLa cells are deformed upon treatment with Cytochalasin. The technique also reveals the deformability of each subpopulation in a mixed, heterogeneous cell sample by the use of both fluorescent markers and mechanical biomarkers. The technique in this study, apart from being relevant to cell biology, will also enable biophysical cellular diagnosis.

  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. Functional inhibition in direction-selective retinal ganglion cells: spatiotemporal extent and intralaminar interactions.

    PubMed

    Stasheff, Steven F; Masland, Richard H

    2002-08-01

    We recorded from ON-OFF direction-selective ganglion cells (DS cells) in the rabbit retina to investigate in detail the inhibition that contributes to direction selectivity in these cells. Using paired stimuli moving sequentially across the cells' receptive fields in the preferred direction, we directly confirmed the prediction of that a wave of inhibition accompanies any moving excitatory stimulus on its null side, at a fixed spatial offset. Varying the interstimulus distance, stimulus size, luminance, and speed yielded a spatiotemporal map of the strength of inhibition within this region. This "null" inhibition was maximal at an intermediate distance behind a moving stimulus: 1/2 to 11/2 times the width of the receptive field. The strength of inhibition depended more on the distance behind the stimulus than on stimulus speed, and the inhibition often lasted 1-2 s. These spatial and temporal parameters appear to account for the known spatial frequency and velocity tuning of ON-OFF DS cells to drifting contrast gratings. Stimuli that elicit distinct ON and OFF responses to leading and trailing edges revealed that an excitatory response of either polarity could inhibit a subsequent response of either polarity. For example, an OFF response inhibited either an ON or OFF response of a subsequent stimulus. This inhibition apparently is conferred by a neural element or network spanning the ON and OFF sublayers of the inner plexiform layer, such as a multistratified amacrine cell. Trials using a stationary flashing spot as a probe demonstrated that the total amount of inhibition conferred on the DS cell was equivalent for stimuli moving in either the null or preferred direction. Apparently the cell does not act as a classic "integrate and fire" neuron, summing all inputs at the soma. Rather, computation of stimulus direction likely involves interactions between excitatory and inhibitory inputs in local regions of the dendrites. PMID:12163551

  16. Tissue-specific neuro-glia interactions determine neurite differentiation in ganglion cells.

    PubMed

    Steinbach, K; Bauch, H; Stier, H; Schlosshauer, B

    2001-03-01

    Guided formation and extension of axons versus dendrites is considered crucial for structuring the nervous system. In the chick visual system, retinal ganglion cells (RGCs) extend their axons into the tectum opticum, but not into glial somata containing retina layers. We addressed the question whether the different glia of retina and tectum opticum differentially affect axon growth. Glial cells were purified from retina and tectum opticum by complement-mediated cytolysis of non-glial cells. RGCs were purified by enzymatic delayering from flat mounted retina. RGCs were seeded onto retinal versus tectal glia monolayers. Subsequent neuritic differentiation was analysed by immunofluorescence microscopy and scanning electron microscopy. Qualitative and quantitative evaluation revealed that retinal glia somata inhibited axons. Time-lapse video recording indicated that axonal inhibition was based on the collapse of lamellipodia- and filopodia-rich growth cones of axons. In contrast to retinal glia, tectal glia supported axonal extension. Notably, retinal glia were not inhibitory for neurons in general, because in control experiments axon extension of dorsal root ganglia was not hampered. Therefore, the axon inhibition by retinal glia was neuron type-specific. In summary, the data demonstrate that homotopic (retinal) glia somata inhibit axonal outgrowth of RGCs, whereas heterotopic (tectal) glia of the synaptic target area support RGC axon extension. The data underscore the pivotal role of glia in structuring the developing nervous system. PMID:11322389

  17. Changes in potassium channel activity following axotomy of B-cells in bullfrog sympathetic ganglion.

    PubMed Central

    Jassar, B S; Pennefather, P S; Smith, P A

    1994-01-01

    1. Whole-cell and microelectrode voltage-clamp techniques were used to investigate the changes in ionic currents and action potential shape that follow axotomy of bullfrog paravertebral sympathetic ganglion B-cells. 2. Axotomy increased M-conductance (gM; muscarine-sensitive, voltage- and time-dependent K+ conductance) by 35% at -30 mV and slowed its deactivation kinetics. 3. The delayed rectifier K+ current (IK; at +50 mV) was reduced in axotomized neurones to 61% of control without any change in activation or deactivation kinetics. Steady-state intracellular Ca2+ levels and leak conductance were unchanged. 4. The fast, voltage-sensitive, Ca(2+)-activated K+ current (IC), evoked from -40 mV, was decreased to about 71% of control (at +30 mV) in axotomized neurones, whereas that evoked from -80 mV was largely unaffected. IC kinetics were also similar in control and axotomized neurones. This suggests that IC channels are not changed after axotomy. 5. In axotomized neurones, commands to +10 from -40 mV had to be extended by 16 ms to evoke voltage-insensitive Ca(2+)-dependent K+ current (IAHP) responses that were similar in magnitude to those observed in control cells. 6. The previously documented, axotomy-induced decrease in Ca2+ current (ICa) due to increased resting inactivation can account for the reduction in IC and IAHP and for the change in the shape of the action potential. PMID:7837094

  18. Simultaneous recording of mouse retinal ganglion cells during epiretinal or subretinal stimulation

    PubMed Central

    Sim, S.L.; Szalewski, R.J.; Johnson, L.J.; Akah, L.E.; Shoemaker, L.E.; Thoreson, W.B.; Margalit, E.

    2015-01-01

    We compared response patterns and electrical receptive fields (ERF) of retinal ganglion cells (RGCs) during epiretinal and subretinal electrical stimulation of isolated mouse retina. Retinas were stimulated with an array of 3200 independently controllable electrodes. Four response patterns were observed: a burst of activity immediately after stimulation (Type I cells, Vision Research (2008), 48, 1562–1568), delayed bursts beginning >25 ms after stimulation (Type II), a combination of both (Type III), and inhibition of ongoing spike activity. Type I responses were produced more often by epiretinal than subretinal stimulation whereas delayed and inhibitory responses were evoked more frequently by subretinal stimulation. Response latencies were significantly shorter with epiretinal than subretinal stimulation. These data suggest that subretinal stimulation is more effective at activating intraretinal circuits than epiretinal stimulation. There was no significant difference in charge threshold between subretinal and epiretinal configurations. ERFs were defined by the stimulating array surface area that successfully stimulated spikes in an RGC. ERFs were complex in shape, similar to receptive fields mapped with light. ERF areas were significantly smaller with subretinal than epiretinal stimulation. This may reflect the greater distance between stimulating electrodes and RGCs in the subretinal configuration. ERFs for immediate and delayed responses mapped within the same Type III cells differed in shape and size, consistent with different sites and mechanisms for generating these two response types. PMID:24863584

  19. Extraction (DSX) from Erigeron breviscapus modulates outward potassium currents in rat retinal ganglion cells

    PubMed Central

    Yin, Shuo; Wang, Zhong-Feng; Duan, Jun-Guo; Ji, Lu; Lu, Xue-Jing

    2015-01-01

    AIM To investigate the effect of DSX, an active component extracted from Erigeron breviscapus, on the voltage-gated outward K+ channel currents in rat retinal ganglion cells (RGCs) by using electrophysiological method, and to explore the possible mechanisms of DSX on optic nerve protection. METHODS Outward K+ currents were recorded by using whole-cell patch-clamp techniques on acutely isolated rat RGCs. Outward K+ currents were induced by a series of depolarizing voltage pulses from a holding potential of -70 mV to +20 mV in an increment of 10 mV. RESULTS Extracellular application of DSX voltage-dependently suppressed both the steady-state and peak current amplitudes of outward K+ currents in rat RGCs. Furthermore, DSX reversibly and dose-dependently inhibited the amplitudes of outward K+ currents of the cells. At +20 mV membrane potential DSX at the concentrations of 0.02 g/L and 0.05 g/L showed no significant effects on the currents. In contrast, DSX at higher concentrations (0.1 g/L, 0.2 g/L and 0.5 g/L) significantly suppressed the current amplitudes. CONCLUSION These results suggest that DSX reversibly and dose-dependently suppress outward K+ channel currents in rat RGCs, which may be one of the possible mechanisms underlying Erigeron breviscapus prevents vision loss and RGC damage caused by glaucoma. PMID:26682155

  20. AMPA-type glutamate receptor subunits are expressed in the avian cochlear hair cells and ganglion cells.

    PubMed

    Reng, D; Hack, I; Müller, M; Smolders, J W

    1999-07-13

    The cellular localization of AMPA-type glutamate receptor subunits was examined in the pigeon inner ear using subunit specific polyclonal antibodies (GluR1-4). In the auditory ganglion cell bodies immunoreactivity for the subunits GluR2/3 and GluR4, but not for GluR1 was detected. The hair cells showed diffuse immunoreactivity for GluR4. Additionally, immunostaining for the subunits GluR2/3 and GluR4 was present below the hair cells. These results indicate that the AMPA type glutamate receptors play a role in neurotransmission at the hair cell afferent synapse in the avian auditory system.

  1. Promotion on the differentiation of retinal Müller cells into retinal ganglion cells by Brn-3b

    PubMed Central

    Wu, Zhen-Kai; Cao, Lan; Zhang, Xue-Yong; Song, Wei-Tao; Xia, Xiao-Bo

    2016-01-01

    AIM To investigate the role of Brn-3b in differentiation process of stem cells derived from retinal Müller cells into the ganglion cell. METHODS The passage culture method of Müller cells from retina of newborn Sprague Dawley rats was carried out by repeated incomplete pancreatic enzyme digestion method. The cells were detected by fluorescence-activated cell sorter (FACS), immunohistochemistry technology and reverse transcription-polymerase chain reaction (RT-PCR) to determine the purity. The third passage of cells was induced in the serum-free dedifferentiation medium. The expression of the specific markers Ki-67 and nestin of retinal stem cells was measured by RT-PCR and Western blot. The cell proliferation of retinal stem cells was detected by 5-ethynyl-2′-deoxyuridine (Edu) staining. The cells were randomly divided into 5 groups as follows: group A: Brn-3bsiRNA group; group B: Brn-3b control siRNA group; group C: pGC-Brn-3b-green fluorescent protein (GFP) group; group D: pGC-GFP group; group E: control group (without any handling). The purified Müller cells were cultured for 3-7d, then, the percentage of ganglion cells was counted by immunofluorescence staining. RESULTS FACS demonstrated the purity of retinal Müller cells was more 97.44%. A few spherical cell spheres appeared. Immunofluorescence staining showed that stem cells within the spheres were positive for retinal stem cell-specific markers nestin (red fluorescence, 92.94%±6.48%) and Ki-67 (green fluorescence, 85.96%±6.04%). Meanwhile, RT-PCR analysis showed cell spheres in the culture to have expressed a battery of transcripts characteristic of stem cells such as nestin and Ki-67, which were absent in the Müller cells. Western blot analysis further confirmed the expression of nestin and Ki-67 in the cell spheres but not in the Müller cells. Edu staining showed most of the nuclei within the cell spheres were stained red (82.80%±6.65%), suggesting the new cell spheres had the capacity for

  2. A synaptic signature for ON- and OFF-center parasol ganglion cells of the primate retina

    PubMed Central

    Crook, Joanna D.; Packer, Orin S.; Dacey, Dennis M.

    2015-01-01

    In the primate retina, parasol ganglion cells contribute to the primary visual pathway via the magnocellular division of the lateral geniculate nucleus, display ON and OFF concentric receptive field structure, nonlinear spatial summation, and high achromatic temporal–contrast sensitivity. Parasol cells may be homologous to the alpha-Y cells of nonprimate mammals where evidence suggests that N-methyl-D-aspartate (NMDA) receptor-mediated synaptic excitation as well as glycinergic disinhibition play critical roles in contrast sensitivity, acting asymmetrically in OFF- but not ON-pathways. Here, light-evoked synaptic currents were recorded in the macaque monkey retina in vitro to examine the circuitry underlying parasol cell receptive field properties. Synaptic excitation in both ON and OFF types was mediated by NMDA as well as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate glutamate receptors. The NMDA-mediated current–voltage relationship suggested high Mg2+ affinity such that at physiological potentials, NMDA receptors contributed ~20% of the total excitatory conductance evoked by moderate stimulus contrasts and temporal frequencies. Postsynaptic inhibition in both ON and OFF cells was dominated by a large glycinergic “crossover” conductance, with a relatively small contribution from GABAergic feedforward inhibition. However, crossover inhibition was largely rectified, greatly diminished at low stimulus contrasts, and did not contribute, via disinhibition, to contrast sensitivity. In addition, attenuation of GABAergic and glycinergic synaptic inhibition left center–surround and Y-type receptive field structure and high temporal sensitivity fundamentally intact and clearly derived from modulation of excitatory bipolar cell output. Thus, the characteristic spatial and temporal–contrast sensitivity of the primate parasol cell arises presynaptically and is governed primarily by modulation of the large AMPA/kainate receptor

  3. Long-term Fluorometholone Topical Use Induces Ganglion Cell Damage in Rats Analyzed With Optical Coherence Tomography.

    PubMed

    Lin, Cheng-Hui; Liao, Po-Lin; Hsiao, George; Li, Ching-Hao; Huang, Shih-Hsuan; Tsai, Chi-Hao; Wu, Man-Ru; Lin, Fan-Li; Ho, Jau-Der; Cheng, Hui-Wen; Cheng, Yu-Wen

    2015-10-01

    To determine the toxic effects of long-term topical usage of fluorometholone (FLM) on ganglion cells using a direct in vivo retinopathological Brown Norway (BN) rat model. The BN rat retinal model was investigated with a minimum of 3 rats and a maximum of 4 rats per group. Rats received vehicle and 0.02% FLM suspension via topical administration 3 times a day for 28 days. The fundus images and retinal vessels were detected on days 1, 14, and 28 using Micron III retinal imaging microscope and fundus fluorescein angiography (FFA). For retinal structures, spectral-domain optical coherence tomography (SD-OCT) images were taken after FFA on days 1, 14, and 28 using an SD-OCT Imaging System. For retinal function, electrical signal transduction of photoreceptors and bipolar cells was determined by electroretinographic (ERG) recording on days 1 and 28 and IOP detection. At the end of the experiment on day 28, immunohistochemistry and TUNEL assay were performed to investigate apoptosis in ganglion cells. Total retina and nerve fiber layer (NFL) to the inner plexiform layer (IPL) were significantly thinner following 28 days of FLM treatment. Hematoxylin and eosin stain showed that there were NFL and ganglion cell layer deformations in the FLM group. With FLM treatment, TUNEL assay showed approximately a 4.68-fold increase in apoptotic cells. Moreover, FLM decreased ERG b-wave amplitude by about 56%. Using ophthalmofundoscopy devices, after 28 days of topical administration, FLM decreased NFL-IPL and total retina thickness. This suggests that long-term FLM induces adverse effects with respect to ganglion cell apoptosis. PMID:26141393

  4. Melanopsin-expressing ganglion cells in primate retina signal colour and irradiance and project to the LGN.

    PubMed

    Dacey, Dennis M; Liao, Hsi-Wen; Peterson, Beth B; Robinson, Farrel R; Smith, Vivianne C; Pokorny, Joel; Yau, King-Wai; Gamlin, Paul D

    2005-02-17

    Human vision starts with the activation of rod photoreceptors in dim light and short (S)-, medium (M)-, and long (L)- wavelength-sensitive cone photoreceptors in daylight. Recently a parallel, non-rod, non-cone photoreceptive pathway, arising from a population of retinal ganglion cells, was discovered in nocturnal rodents. These ganglion cells express the putative photopigment melanopsin and by signalling gross changes in light intensity serve the subconscious, 'non-image-forming' functions of circadian photoentrainment and pupil constriction. Here we show an anatomically distinct population of 'giant', melanopsin-expressing ganglion cells in the primate retina that, in addition to being intrinsically photosensitive, are strongly activated by rods and cones, and display a rare, S-Off, (L + M)-On type of colour-opponent receptive field. The intrinsic, rod and (L + M) cone-derived light responses combine in these giant cells to signal irradiance over the full dynamic range of human vision. In accordance with cone-based colour opponency, the giant cells project to the lateral geniculate nucleus, the thalamic relay to primary visual cortex. Thus, in the diurnal trichromatic primate, 'non-image-forming' and conventional 'image-forming' retinal pathways are merged, and the melanopsin-based signal might contribute to conscious visual perception. PMID:15716953

  5. PSA modification of NCAM supports the survival of injured retinal ganglion cells in adulthood.

    PubMed

    Lobanovskaya, Natalia; Zharkovsky, Tamara; Jaako, Külli; Jürgenson, Monika; Aonurm-Helm, Anu; Zharkovsky, Alexander

    2015-11-01

    Neural cell adhesion molecule (NCAM) is known as the cell surface glycoprotein, and it belongs to the immunoglobulin superfamily of adhesion molecules. Polysialic acid (PSA) is a carbohydrate attached to NCAM via either of two specific sialyltransferases: ST8SiaII and ST8SiaIV. Polysialylated neural cell adhesion molecule (PSA-NCAM) mediates cell interactions, plays a role in axon growth, migration, synaptic plasticity during development and cell regeneration. Some evidence has shown that PSA-NCAM supports the survival of neurons. It was demonstrated that PSA-NCAM is present in abundance in the retina during development and in adulthood. The aim of this study was to investigate whether PSA-NCAM promotes retinal ganglion cell (RGC) survival in transgenic mice with deficiencies in sialyltransferases or NCAM or after the administration of endoneuraminidase (Endo-N). RGC injury was induced by intravitreal administration of kainic acid (KA). These studies showed that injection of Endo-N after 14 days enhances the toxicity of KA to RGCs in wild-type (WT) mice by 18%. In contrast, in knockout mice (ST8SiaII-/-, ST8SiaIV-/-, NCAM-/-), survival of RGCs after KA injury did not change. Deficiencies of either ST8SiaII or ST8SiaIV did not influence the level of PSA-NCAM in the adult retina, however, in neonatal animals, decreased levels of PSA-NCAM were observed. In knockout ST8SiaII-/- adults, a reduced number of RGCs was detected, whereas in contrast, increased numbers of RGCs were noted in NCAM-/- mice. In conclusion, these data demonstrate that PSA-NCAM supports the survival of injured RGCs in adulthood. However, the role of PSA-NCAM in the adult retina requires further clarification. PMID:26319680

  6. 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

  7. The rod-cone shift and its effect on ganglion cells in the cat's retina.

    PubMed

    Chan, L H; Freeman, A W; Cleland, B G

    1992-12-01

    We examined how several characteristics of cat retinal ganglion cells--receptive field size, spatial resolution, and centre-surround antagonism--change with background illumination. Spectral sensitivity was also measured to see how these changes depend on the rod-cone shift. The radius of the centre mechanism changed very little across the mesopic range. The absence of a change can be attributed to the connections rods make with cones, and to the small spatial spread of rods which connect to a cone. The highest spatial frequency to which a cell could respond dropped sharply with falling background illumination. This loss of spatial resolution is due partly to increasing receptive field size, and partly to loss of contrast gain. Centre-surround antagonism approached zero as background illumination fell. The loss of antagonism could have been due to either a change in the subtractive relationship between centre and surround, or due to a loss of surround strength relative to centre strength; the latter was shown to be the case. PMID:1287998

  8. Projection of the retinal ganglion cells to the tectum differentiated from the prosencephalon.

    PubMed

    Nakamura, H; Matsui, K A; Takagi, S; Fujisawa, H

    1991-08-01

    The alar plate of the prosencephalon differentiates into a tectum-like structure when transplanted into the mesencephalon around the 10-somite stage. Here, we report on the projection pattern of the retinal ganglion cells to the transplants. Optic nerve fibers were labeled with horseradish peroxidase (HRP) and 3H-proline, and the innervation of the optic nerve fibers to the chimeric tectum was analyzed by HRP histochemistry on whole-mounted specimens, by autoradiography and by electron microscopy on embryonic day 16. In the chimeric tectum, the transplant was distinguished from the host by difference in nuclear structure between the quail and the chick cells. It was shown that the transplant had the laminar pattern of the optic tectum when the transplant was integrated into the host mesencephalon. The whole-mount HRP histochemistry showed that the optic nerve fibers extend to the transplants. Autoradiography showed that the distribution pattern of silver grains was similar in both the host and the transplant. These results may indicate that the optic nerve fibers turn to the transplant and terminate on the transplant. Electron microscopy further confirmed that optic nerve fibers ended by making synaptic contacts with the dendrites in the transplant region of the tectum. These results indicate that the transplant with the laminar pattern of the optic tectum is a true tectum receiving input from the eye. PMID:1661870

  9. Inhibitory input to the direction-selective ganglion cell is saturated at low contrast.

    PubMed

    Lipin, Mikhail Y; Taylor, W Rowland; Smith, Robert G

    2015-08-01

    Direction-selective ganglion cells (DSGCs) respond selectively to motion toward a "preferred" direction, but much less to motion toward the opposite "null" direction. Directional signals in the DSGC depend on GABAergic inhibition and are observed over a wide range of speeds, which precludes motion detection based on a fixed temporal correlation. A voltage-clamp analysis, using narrow bar stimuli similar in width to the receptive field center, demonstrated that inhibition to DSGCs saturates rapidly above a threshold contrast. However, for wide bar stimuli that activate both the center and surround, inhibition depends more linearly on contrast. Excitation for both wide and narrow bars was also more linear. We propose that positive feedback, likely within the starburst amacrine cell or its network, produces steep saturation of inhibition at relatively low contrast. This mechanism renders GABA release essentially contrast and speed invariant, which enhances directional signals for small objects and thereby increases the signal-to-noise ratio for direction-selective signals in the spike train over a wide range of stimulus conditions. The steep saturation of inhibition confers to a neuron immunity to noise in its spike train, because when inhibition is strong no spikes are initiated.

  10. 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

  11. Substance P-mediated membrane currents in voltage-clamped guinea pig inferior mesenteric ganglion cells.

    PubMed

    Griffith, W H; Hills, J M; Brown, D A

    1988-01-01

    Responses to substance P (SP) and to hypogastric nerve stimulation were recorded from voltage-clamped guinea pig inferior mesenteric ganglion (IMG) neurons, and compared with those to muscarine. Muscarine produced a voltage-dependent inward current accompanied by a reduced input conductance and inhibition of IM a time- and voltage-dependent K+-current (Brown and Adams: Nature 283:673-676, 1980). SP also produced an inward current, accompanied by a fall in input conductance (20 out of 31 cells) or a rise in input conductance (7 out of 31 cells). The fall in input conductance was not accompanied by an inhibition of M-current (unlike frog ganglia: Adams et al.: British Journal of Pharmacology 79:330-333, 1983) or an inhibition of the inward rectifier current (unlike globus pallidus neurons: Stanfield et al.: Nature 315:498-501, 1985). Repetitive hypogastric nerve stimulation (10-20 Hz, 2-10 s) produced a slow inward postsynaptic current lasting 1-3 min, with decreases or increases of input conductance matching those produced by SP. The postsynaptic current did not show a consistent or reproducible change in amplitude on varying the holding potential between -90 and -25 mV. It is concluded that SP and hypogastric stimulation produce complex and variable changes in ionic conductance in IMG neurons.

  12. Characterizing and modeling the intrinsic light response of rat ganglion-cell photoreceptors.

    PubMed

    Walch, Olivia J; Zhang, L Samantha; Reifler, Aaron N; Dolikian, Michael E; Forger, Daniel B; Wong, Kwoon Y

    2015-11-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) mediate both image-forming vision and non-image-forming visual responses such as pupillary constriction and circadian photoentrainment. Five types of ipRGCs, named M1-M5, have been discovered in rodents. To further investigate their photoresponse properties, we made multielectrode array spike recordings from rat ipRGCs, classified them into M1, M2/M4, and M3/M5 clusters, and measured their intrinsic, melanopsin-based responses to single and flickering light pulses. Results showed that ipRGC spiking can track flickers up to ∼0.2 Hz in frequency and that flicker intervals between 5 and 14 s evoke the most spikes. We also learned that melanopsin's integration time is intensity and cluster dependent. Using these data, we constructed a mathematical model for each cluster's intrinsic photoresponse. We found that the data for the M1 cluster are best fit by a model that assumes a large photoresponse, causing the cell to enter depolarization block. Our models also led us to hypothesize that the M2/M4 and M3/M5 clusters experience comparable photoexcitation but that the M3/M5 cascade decays significantly faster than the M2/M4 cascade, resulting in different response waveforms between these clusters. These mathematical models will help predict how each ipRGC cluster might respond to stimuli of any waveform and could inform the invention of lighting technologies that promote health through melanopsin stimulation.

  13. Intraretinal projection of retinal ganglion cell axons as a model system for studying axon navigation

    PubMed Central

    Bao, Zheng-Zheng

    2008-01-01

    The initial step of retinal ganglion cell (RGC) axon pathfinding involves directed growth of RGC axons toward the center of the retina, the optic disc, a process termed “intraretinal guidance”. Due to the accessibility of the system, and with various embryological, molecular, and genetic approaches, significant progress has been made in recent years toward understanding the mechanisms involved in the precise guidance of the RGC axons. As axons are extending from RGCs located throughout the retina, a multitude of factors expressed along with the differentiation wave are important for the guidance of the RGC axons. To ensure that the RGC axons are oriented correctly, restricted to the optic fiber layer (OFL) of the retina, and exit the eye properly, different sets of positive and negative factors cooperate in the process. Fasciculation mediated by a number of cell adhesion molecules (CAMs) and modulation of axonal response to guidance factors provide additional mechanisms to ensure proper guidance of the RGC axons. The intraretinal axon guidance thus serves as an excellent model system for studying how different signals are regulated, modulated and integrated for guiding a large number of axons in three-dimensional space. PMID:17320832

  14. c-Jun N-terminal kinase 3 expression in the retina of ocular hypertension mice: a possible target to reduce ganglion cell apoptosis.

    PubMed

    He, Yue; Chen, Jie; Zhang, Shu-Guang; Yuan, Yuan-Sheng; Li, Yan; Lv, Hong-Bin; Gan, Jin-Hua

    2015-03-01

    Glaucoma, a type of optic neuropathy, is characterized by the loss of retinal ganglion cells. It remains controversial whether c-Jun N-terminal kinase (JNK) participates in the apoptosis of retinal ganglion cells in glaucoma. This study sought to explore a possible mechanism of action of JNK signaling pathway in glaucoma-induced retinal optic nerve damage. We established a mouse model of chronic ocular hypertension by reducing the aqueous humor followed by photocoagulation using the laser ignition method. Results showed significant pathological changes in the ocular tissues after the injury. Apoptosis of retinal ganglion cells increased with increased intraocular pressure, as did JNK3 mRNA expression in the retina. These data indicated that the increased expression of JNK3 mRNA was strongly associated with the increase in intraocular pressure in the retina, and correlated positively with the apoptosis of retinal ganglion cells. PMID:25878592

  15. c-Jun N-terminal kinase 3 expression in the retina of ocular hypertension mice: a possible target to reduce ganglion cell apoptosis

    PubMed Central

    He, Yue; Chen, Jie; Zhang, Shu-guang; Yuan, Yuan-sheng; Li, Yan; Lv, Hong-bin; Gan, Jin-hua

    2015-01-01

    Glaucoma, a type of optic neuropathy, is characterized by the loss of retinal ganglion cells. It remains controversial whether c-Jun N-terminal kinase (JNK) participates in the apoptosis of retinal ganglion cells in glaucoma. This study sought to explore a possible mechanism of action of JNK signaling pathway in glaucoma-induced retinal optic nerve damage. We established a mouse model of chronic ocular hypertension by reducing the aqueous humor followed by photocoagulation using the laser ignition method. Results showed significant pathological changes in the ocular tissues after the injury. Apoptosis of retinal ganglion cells increased with increased intraocular pressure, as did JNK3 mRNA expression in the retina. These data indicated that the increased expression of JNK3 mRNA was strongly associated with the increase in intraocular pressure in the retina, and correlated positively with the apoptosis of retinal ganglion cells. PMID:25878592

  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. Norrin attenuates protease-mediated death of transformed retinal ganglion cells

    PubMed Central

    Lin, Song; Cheng, Mei; Dailey, Wendelin; Drenser, Kimberly

    2009-01-01

    Purpose To investigate the effects of norrin, a nonconventional ligand for Wingless-Int (Wnt)-beta-catenin signaling pathway, on protease-mediated death of transformed rat retinal ganglion cells (RGC-5). Methods Transformed RGC-5 cells were treated with 2.0 μM staurosporine (SS), a broad-spectrum protein kinase-C inhibitor, to induce growth arrest, differentiation, and elevated levels of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA). RGC-5 cells were also treated with 2.0 μM SS and varying doses of recombinant norrin (3.125 to 100 ng/ml). Activation of Wnt pathway was assessed by nuclear translocation of beta-catenin. Proteolytic activity of tPA and uPA was determined by zymography assays and cell viability was determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assays. Expression and phosphorylation of the low-density lipoprotein-related receptor-1 (LRP-1), a cell surface receptor for tPA and uPA, was determined by immunoprecipitation and western blot analysis. Results Compared to RGC-5 cells left untreated, cells treated with either SS alone or SS and norrin secreted elevated levels of tPA and uPA. A significant number of RGC-5 cells treated with only SS underwent cell death, whereas cells treated with SS and norrin did not, even though RGC-5 cells secreted elevated levels of tPA and uPA under both treatment conditions. Although norrin activated the Wnt pathway, Dickkopf related protein 1 (Dkk1), an inhibitor of Wnt/beta-catenin pathway, failed to completely block norrin’s neuroprotective effects. Assays for expression and phosphorylation of LRP-1 indicated that tPA and uPA cause RGC-5 cell death, in part, by reducing phosphorylation of LRP-1, whereas norrin attenuated tPA and uPA-mediated RGC cell death, in part, by restoring phosphorylation of LRP-1. Conclusions Our results suggest that norrin attenuates tPA- and uPA-mediated death of RGC-5 cells by activating Wnt/beta-catenin pathway and by

  18. Research on ganglion cell responses after laser exposure of the retina. Final report Jan 77-Dec 78

    SciTech Connect

    Wolbarsht, M.L.

    1980-05-01

    Electrophysiological recordings were made from retinal ganglion cells in the macula (including fovea) of several species of Macaque monkeys. After exposure to high-intensity argon or HeNe lasers both above and below the lesion level, the receptive fields lacked a peripheral portion. This was accompanied by a slight increase in the central portion of the receptive field. Some quite large receptive fields were found around the fovea, often extending through it. The large receptive fields could also extend through the site of a laser lesion. No unsymmetrical changes in the receptive field were seen, even in receptive fields adjacent to, or partially within, a laser lesion site. Histological examination did not show any changes in the retinal organization adjacent to laser lesion even where the ganglion cells had center-only receptive fields.

  19. Identification of retinal ganglion cell neuroprotection conferred by platelet-derived growth factor through analysis of the mesenchymal stem cell secretome

    PubMed Central

    DeKorver, Nicholas W.; Levasseur, Victoria A.; Osborne, Andrew; Tassoni, Alessia; Lorber, Barbara; Heller, Janosch P.; Villasmil, Rafael; Bull, Natalie D.

    2014-01-01

    The development of neuroprotective strategies to attenuate retinal ganglion cell death could lead to novel therapies for chronic optic neuropathies such as glaucoma. Intravitreal transplantation of mesenchymal stem cells slows retinal ganglion cell death in models of optic nerve injury, but the mechanism of action remains unclear. Here we characterized the neuroprotective effects of mesenchymal stem cells and mesenchymal stem cell-derived factors in organotypic retinal explant culture and an in vivo model of ocular hypertensive glaucoma. Co-culture of rat and human bone marrow-derived mesenchymal stem cells with retinal explants increased retinal ganglion cell survival, after 7 days ex vivo, by ∼2-fold and was associated with reduced apoptosis and increased nerve fibre layer and inner plexiform layer thicknesses. These effects were not demonstrated by co-culture with human or mouse fibroblasts. Conditioned media from mesenchymal stem cells conferred neuroprotection, suggesting that the neuroprotection is mediated, at least partly, by secreted factors. We compared the concentrations of 29 factors in human mesenchymal stem cell and fibroblast conditioned media, and identified 11 enriched in the mesenchymal stem cell secretome. Treatment of retinal explants with a cocktail of these factors conferred retinal ganglion cell neuroprotection, with factors from the platelet-derived growth factor family being the most potent. Blockade of platelet-derived growth factor signalling with neutralizing antibody or with small molecule inhibitors of platelet-derived growth factor receptor kinase or downstream phosphatidylinositol 3 kinase eliminated retinal ganglion cell neuroprotection conferred by mesenchymal stem cell co-culture. Intravitreal injection of platelet-derived growth factor -AA or -AB led to profound optic nerve neuroprotection in vivo following experimental induction of elevated intraocular pressure. These data demonstrate that mesenchymal stem cells secrete a

  20. Effects of remote stimulation on the mean firing rate of cat retinal ganglion cells.

    PubMed

    Passaglia, C L; Enroth-Cugell, C; Troy, J B

    2001-08-01

    Visual stimulation outside the classical receptive field can have pronounced effects on cat retinal ganglion cells. We characterized the effects of such stimulation by varying the contrast, spatial frequency, temporal frequency, and spatial extent of remote drifting sinusoidal gratings. We found that the mean firing rate of some X-cells and most Y-cells increased to remote gratings of low spatial frequency and high temporal frequency and decreased to ones of high spatial frequency and low temporal frequency. At least 10-20% contrast was required to see either effect, which quickly saturated at higher contrasts. Both effects were substantial, raising or lowering the mean rate of some cells by over 40 impulses/sec. Classical receptive field mechanisms were not involved because the remote gratings caused little or no response modulation. We conclude that, in addition to a mean-increasing mechanism known from previous work, a mean-decreasing one operates in the cat retina. This mechanism prefers slower motion and resolves finer patterns than the mean-increasing one. We incorporate these findings into a model consisting of pools of small and large rectifying subunits of opposite polarity. Model estimates of subunit radius were primarily independent of eccentricity and averaged approximately 0.15 and approximately 0.60 degrees for the mean-decreasing and mean-increasing mechanisms, respectively. This makes the subunits approximately the center size of central X- and Y-cells. Because smooth movements of the eyes, head, or body should engage these mechanisms under natural conditions, we propose that the mean rate changes that would ensue are functionally relevant to cat vision. PMID:11466451

  1. Mitochondrial complex I deficiency leads to inflammation and retinal ganglion cell death in the Ndufs4 mouse

    PubMed Central

    Yu, Alfred K.; Song, Lanying; Murray, Karl D.; van der List, Deborah; Sun, Chao; Shen, Yan; Xia, Zhengui; Cortopassi, Gino A.

    2015-01-01

    Mitochondrial complex I (NADH dehydrogenase) is a major contributor to neuronal energetics, and mutations in complex I lead to vision loss. Functional, neuroanatomical and transcriptional consequences of complex I deficiency were investigated in retinas of the Ndufs4 knockout mouse. Whole-eye ERGs and multielectrode arrays confirmed a major retinal ganglion cell functional loss at P32, and retinal ganglion cell loss at P42. RNAseq demonstrated a mild and then sharp increase in innate immune and inflammatory retinal transcripts at P22 and P33, respectively, which were confirmed with QRT-PCR. Intraperitoneal injection of the inflammogen lipopolysaccharide further reduced retinal ganglion cell function in Ndufs4 KO, supporting the connection between inflammatory activation and functional loss. Complex I deficiency in the retina clearly caused innate immune and inflammatory markers to increase coincident with loss of vision, and RGC functional loss. How complex I incites inflammation and functional loss is not clear, but could be the result of misfolded complex I generating a ‘non-self’ response, and induction of innate immune response transcripts was observed before functional loss at P22, including β-2 microglobulin and Cx3cr1, and during vision loss at P31 (B2m, Tlr 2, 3, 4, C1qa, Cx3cr1 and Fas). These data support the hypothesis that mitochondrial complex I dysfunction in the retina triggers an innate immune and inflammatory response that results in loss of retinal ganglion cell function and death, as in Leber's hereditary Optic Neuropathy and suggests novel therapeutic routes to counter mitochondrial defects that contribute to vision loss. PMID:25652399

  2. The structural effect of systemic NGF treatment on permanently axotomised dorsal root ganglion cells in adult rats

    PubMed Central

    TANDRUP, T.; VESTERGAARD, S.; TOMLINSON, D. R.; DIEMEL, L. T.; JAKOBSEN, J.

    1999-01-01

    The effect of systemic NGF treatment on loss and shrinkage of dorsal root ganglion cells was studied in adult male rats after permanent axotomy. Nineteen 16 to 18-wk-old rats had their right 5th lumbar spinal nerve ligated and cut approximately 7 mm peripheral to the ganglion. Two days before the operation, treatment with subcutaneous injections of human recombinant NGF (1.0–0.5 mg/kg/day) was started in 9 test rats; 10 controls were given saline injections. After 1 mo the levels of substance P (SP) and calcitonin gene related peptide (CGRP) were significantly increased in intact sciatic nerve. The number and mean volume of perikarya were estimated using assumption-free stereological techniques including vertical sections, the Cavalieri principle, optical disectors, the planar rotator and systematic sampling techniques. Systemic NGF administration had no influence on survival of primary sensory neurons after axotomy. The number of perikarya was 14300 ( S.D.=1800) in axotomised ganglia in control rats versus 14700 ( S.D.=2100) in axotomised ganglia of NGF treated rats. The reduction of perikarya volume after axotomy was significantly less after NGF treatment (11600 μm3 in the control group versus 8000 μm3 in the NGF treated group). However, the apparent protection of NGF-treatment on perikaryal volume is explained by a hitherto unrecognised size effect on nonaxotomised dorsal root ganglion cells. The untreated rats had a mean volume of 24700 μm3 ( S.D.=2700 μm 3) whereas rats treated with NGF had a volume of 20400 μm3 ( S.D.=1700 μm3) on the nonaxotomised side. In conclusion, systemic NGF treatment in adult rats has no effect on dorsal root ganglion cell loss in permanent axotomy whereas perikaryal size of intact nonaxotomised cells is reduced. PMID:10386775

  3. Acoustic separation of circulating tumor cells.

    PubMed

    Li, Peng; Mao, Zhangming; Peng, Zhangli; Zhou, Lanlan; Chen, Yuchao; Huang, Po-Hsun; Truica, Cristina I; Drabick, Joseph J; El-Deiry, Wafik S; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2015-04-21

    Circulating tumor cells (CTCs) are important targets for cancer biology studies. To further elucidate the role of CTCs in cancer metastasis and prognosis, effective methods for isolating extremely rare tumor cells from peripheral blood must be developed. Acoustic-based methods, which are known to preserve the integrity, functionality, and viability of biological cells using label-free and contact-free sorting, have thus far not been successfully developed to isolate rare CTCs using clinical samples from cancer patients owing to technical constraints, insufficient throughput, and lack of long-term device stability. In this work, we demonstrate the development of an acoustic-based microfluidic device that is capable of high-throughput separation of CTCs from peripheral blood samples obtained from cancer patients. Our method uses tilted-angle standing surface acoustic waves. Parametric numerical simulations were performed to design optimum device geometry, tilt angle, and cell throughput that is more than 20 times higher than previously possible for such devices. We first validated the capability of this device by successfully separating low concentrations (∼100 cells/mL) of a variety of cancer cells from cell culture lines from WBCs with a recovery rate better than 83%. We then demonstrated the isolation of CTCs in blood samples obtained from patients with breast cancer. Our acoustic-based separation method thus offers the potential to serve as an invaluable supplemental tool in cancer research, diagnostics, drug efficacy assessment, and therapeutics owing to its excellent biocompatibility, simple design, and label-free automated operation while offering the capability to isolate rare CTCs in a viable state.

  4. Acoustic separation of circulating tumor cells

    PubMed Central

    Li, Peng; Mao, Zhangming; Peng, Zhangli; Zhou, Lanlan; Chen, Yuchao; Huang, Po-Hsun; Truica, Cristina I.; Drabick, Joseph J.; El-Deiry, Wafik S.; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2015-01-01

    Circulating tumor cells (CTCs) are important targets for cancer biology studies. To further elucidate the role of CTCs in cancer metastasis and prognosis, effective methods for isolating extremely rare tumor cells from peripheral blood must be developed. Acoustic-based methods, which are known to preserve the integrity, functionality, and viability of biological cells using label-free and contact-free sorting, have thus far not been successfully developed to isolate rare CTCs using clinical samples from cancer patients owing to technical constraints, insufficient throughput, and lack of long-term device stability. In this work, we demonstrate the development of an acoustic-based microfluidic device that is capable of high-throughput separation of CTCs from peripheral blood samples obtained from cancer patients. Our method uses tilted-angle standing surface acoustic waves. Parametric numerical simulations were performed to design optimum device geometry, tilt angle, and cell throughput that is more than 20 times higher than previously possible for such devices. We first validated the capability of this device by successfully separating low concentrations (∼100 cells/mL) of a variety of cancer cells from cell culture lines from WBCs with a recovery rate better than 83%. We then demonstrated the isolation of CTCs in blood samples obtained from patients with breast cancer. Our acoustic-based separation method thus offers the potential to serve as an invaluable supplemental tool in cancer research, diagnostics, drug efficacy assessment, and therapeutics owing to its excellent biocompatibility, simple design, and label-free automated operation while offering the capability to isolate rare CTCs in a viable state. PMID:25848039

  5. Acoustic separation of circulating tumor cells.

    PubMed

    Li, Peng; Mao, Zhangming; Peng, Zhangli; Zhou, Lanlan; Chen, Yuchao; Huang, Po-Hsun; Truica, Cristina I; Drabick, Joseph J; El-Deiry, Wafik S; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2015-04-21

    Circulating tumor cells (CTCs) are important targets for cancer biology studies. To further elucidate the role of CTCs in cancer metastasis and prognosis, effective methods for isolating extremely rare tumor cells from peripheral blood must be developed. Acoustic-based methods, which are known to preserve the integrity, functionality, and viability of biological cells using label-free and contact-free sorting, have thus far not been successfully developed to isolate rare CTCs using clinical samples from cancer patients owing to technical constraints, insufficient throughput, and lack of long-term device stability. In this work, we demonstrate the development of an acoustic-based microfluidic device that is capable of high-throughput separation of CTCs from peripheral blood samples obtained from cancer patients. Our method uses tilted-angle standing surface acoustic waves. Parametric numerical simulations were performed to design optimum device geometry, tilt angle, and cell throughput that is more than 20 times higher than previously possible for such devices. We first validated the capability of this device by successfully separating low concentrations (∼100 cells/mL) of a variety of cancer cells from cell culture lines from WBCs with a recovery rate better than 83%. We then demonstrated the isolation of CTCs in blood samples obtained from patients with breast cancer. Our acoustic-based separation method thus offers the potential to serve as an invaluable supplemental tool in cancer research, diagnostics, drug efficacy assessment, and therapeutics owing to its excellent biocompatibility, simple design, and label-free automated operation while offering the capability to isolate rare CTCs in a viable state. PMID:25848039

  6. Sorting drops and cells with acoustics: acoustic microfluidic fluorescence-activated cell sorter.

    PubMed

    Schmid, Lothar; Weitz, David A; Franke, Thomas

    2014-10-01

    We describe a versatile microfluidic fluorescence-activated cell sorter that uses acoustic actuation to sort cells or drops at ultra-high rates. Our acoustic sorter combines the advantages of traditional fluorescence-activated cell (FACS) and droplet sorting (FADS) and is applicable for a multitude of objects. We sort aqueous droplets, at rates as high as several kHz, into two or even more outlet channels. We can also sort cells directly from the medium without prior encapsulation into drops; we demonstrate this by sorting fluorescently labeled mouse melanoma cells in a single phase fluid. Our acoustic microfluidic FACS is compatible with standard cell sorting cytometers, yet, at the same time, enables a rich variety of more sophisticated applications.

  7. 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.

  8. Developmental maturation of passive electrical properties in retinal ganglion cells of rainbow trout

    PubMed Central

    Picones, Arturo; Chung, S Clare; Korenbrot, Juan I

    2003-01-01

    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

  9. Physiological and morphological characterization of ganglion cells in the salamander retina.

    PubMed

    Wang, Jing; Jacoby, Roy; Wu, Samuel M

    2016-02-01

    Retinal ganglion cells (RGCs) integrate visual information from the retina and transmit collective signals to the brain. A systematic investigation of functional and morphological characteristics of various types of RGCs is important to comprehensively understand how the visual system encodes and transmits information via various RGC pathways. This study evaluated both physiological and morphological properties of 67 RGCs in dark-adapted flat-mounted salamander retina by examining light-evoked cation and chloride current responses via voltage-clamp recordings and visualizing morphology by Lucifer yellow fluorescence with a confocal microscope. Six groups of RGCs were described: asymmetrical ON-OFF RGCs, symmetrical ON RGCs, OFF RGCs, and narrow-, medium- and wide-field ON-OFF RGCs. Dendritic field diameters of RGCs ranged 102-490 μm: narrow field (<200 μm, 31% of RGCs), medium field (200-300 μm, 45%) and wide field (>300 μm, 24%). Dendritic ramification patterns of RGCs agree with the sublamina A/B rule. 34% of RGCs were monostratified, 24% bistratified and 42% diffusely stratified. 70% of ON RGCs and OFF RGCs were monostratified. Wide-field RGCs were diffusely stratified. 82% of RGCs generated light-evoked ON-OFF responses, while 11% generated ON responses and 7% OFF responses. Response sensitivity analysis suggested that some RGCs obtained separated rod/cone bipolar cell inputs whereas others obtained mixed bipolar cell inputs. 25% of neurons in the RGC layer were displaced amacrine cells. Although more types may be defined by more refined classification criteria, this report is to incorporate more physiological properties into RGC classification.

  10. Physiological and morphological characterization of ganglion cells in the salamander retina.

    PubMed

    Wang, Jing; Jacoby, Roy; Wu, Samuel M

    2016-02-01

    Retinal ganglion cells (RGCs) integrate visual information from the retina and transmit collective signals to the brain. A systematic investigation of functional and morphological characteristics of various types of RGCs is important to comprehensively understand how the visual system encodes and transmits information via various RGC pathways. This study evaluated both physiological and morphological properties of 67 RGCs in dark-adapted flat-mounted salamander retina by examining light-evoked cation and chloride current responses via voltage-clamp recordings and visualizing morphology by Lucifer yellow fluorescence with a confocal microscope. Six groups of RGCs were described: asymmetrical ON-OFF RGCs, symmetrical ON RGCs, OFF RGCs, and narrow-, medium- and wide-field ON-OFF RGCs. Dendritic field diameters of RGCs ranged 102-490 μm: narrow field (<200 μm, 31% of RGCs), medium field (200-300 μm, 45%) and wide field (>300 μm, 24%). Dendritic ramification patterns of RGCs agree with the sublamina A/B rule. 34% of RGCs were monostratified, 24% bistratified and 42% diffusely stratified. 70% of ON RGCs and OFF RGCs were monostratified. Wide-field RGCs were diffusely stratified. 82% of RGCs generated light-evoked ON-OFF responses, while 11% generated ON responses and 7% OFF responses. Response sensitivity analysis suggested that some RGCs obtained separated rod/cone bipolar cell inputs whereas others obtained mixed bipolar cell inputs. 25% of neurons in the RGC layer were displaced amacrine cells. Although more types may be defined by more refined classification criteria, this report is to incorporate more physiological properties into RGC classification. PMID:26731645

  11. Roles of PACAP-containing retinal ganglion cells in circadian timing.

    PubMed

    Hannibal, Jens

    2006-01-01

    The brain's biological clock located in the suprachiasmatic nucleus (SCN) generates circadian rhythms in physiology and behavior. The clock-driven rhythms need daily adjustment (entrainment) to be synchronized with the astronomical day of 24 h. The most important stimulus for entrainment of the clock is the light-dark (LD) cycle. In this review functional elements of the light entrainment pathway will be considered with special focus on the neurotransmitter pituitary adenylate cyclase-activating polypeptide (PACAP), which is found exclusively in the monosynaptic neuronal pathway mediating light information to the SCN, the retinohypothalamic tract (RHT). The retinal ganglion cells of the RHT are intrinsically photosensitive due to the expression of melanopsin and seem to constitute a non-image forming photosensitive system in the mammalian eye regulating circadian timing, masking behavior, light-regulated melatonin secretion, and the pupillary light reflex. Evidence from in vitro and in vivo studies and studies of mice lacking PACAP and the specific PACAP receptor (PAC1) indicate that PACAP and glutamate are neurotransmitters in the RHT which in a clock and concentration-dependent manner interact during light entrainment of the clock.

  12. 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

  13. 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.

  14. Disease Gene Candidates Revealed by Expression Profiling of Retinal Ganglion Cell Development

    PubMed Central

    Wang, Jack T.; Kunzevitzky, Noelia J.; Dugas, Jason C.; Cameron, Meghan; Barres, Ben A.; Goldberg, Jeffrey L.

    2010-01-01

    To what extent do postmitotic neurons regulate gene expression during development or after injury? We took advantage of our ability to highly purify retinal ganglion cells (RGCs) to profile their pattern of gene expression at 13 ages from embryonic day 17 through postnatal day 21. We found that a large proportion of RGC genes are regulated dramatically throughout their postmitotic development, although the genes regulated through development in vivo generally are not regulated similarly by RGCs allowed to age in vitro. Interestingly, we found that genes regulated by developing RGCs are not generally correlated with genes regulated in RGCs stimulated to regenerate their axons. We unexpectedly found three genes associated with glaucoma, optineurin, cochlin, and CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), previously thought to be primarily expressed in the trabecular meshwork, which are highly expressed by RGCs and regulated through their development. We also identified several other RGC genes that are encoded by loci linked to glaucoma. The expression of glaucoma-linked genes by RGCs suggests that, at least in some cases, RGCs may be directly involved in glaucoma pathogenesis rather than indirectly involved in response to increased intraocular pressure. Consistent with this hypothesis, we found that CYP1B1 overexpression potentiates RGC survival. PMID:17687037

  15. 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

  16. Endocannabinoid signaling enhances visual responses through modulation of intracellular chloride levels in retinal ganglion cells.

    PubMed

    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. PMID:27501334

  17. Multielectrode array recordings reveal physiological diversity of intrinsically photosensitive retinal ganglion cells in the chick embryo.

    PubMed

    Neumann, Tanja; Ziegler, Christiane; Blau, Axel

    2008-05-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) play important roles in non-image forming photoreception and participate in the regulation of the circadian rhythm and the pupillary light reflex. The aim of the present work was to characterize the light response of ipRGCs at two developmental stages of the embryonic chick. The electrophysiological study was based on comparative multielectrode array recordings from acute retinal slices. To ensure that light was the only source of excitation, intercellular activity modulation by gap junctions and chemical synapses was inhibited by carbenoxolone and bafilomycin A1, respectively. Action potentials evoked by blue light were detected as early as day 13 of embryonic development, which is notably earlier than the completion of the maturation process of functional rods and cones. Three different response types were distinguished by their response latency and sensitivity to different illumination intensities. At this point it is not clear whether these types just represent different maturation stages or have different morphologies and functions with respect to the non-image forming visual system and circadian entrainment.

  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. PMID:26793063

  19. Neural coding properties based on spike timing and pattern correlation of retinal ganglion cells

    PubMed Central

    Gong, Han-Yan; Zhang, Ying-Ying; Liang, Pei-Ji

    2010-01-01

    Correlation between spike trains or neurons sometimes indicates certain neural coding rules in the visual system. In this paper, the relationship between spike timing correlation and pattern correlation is discussed, and their ability to represent stimulus features is compared to examine their coding strategies not only in individual neurons but also in population. Two kinds of stimuli, natural movies and checkerboard, are used to arouse firing activities in chicken retinal ganglion cells. The spike timing correlation and pattern correlation are calculated by cross-correlation function and Lempel–Ziv distance respectively. According to the correlation values, it is demonstrated that spike trains with similar spike patterns are not necessarily concerted in firing time. Moreover, spike pattern correlation values between individual neurons’ responses reflect the difference of natural movies and checkerboard; neurons cooperate with each other with higher pattern correlation values which represent spatiotemporal correlations during response to natural movies. Spike timing does not reflect stimulus features as obvious as spike patterns, caused by their particular coding properties or physiological foundation. As a result, separating the pattern correlation out of traditional timing correlation concept uncover additional insight in neural coding. PMID:22132042

  20. 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. PMID:23295345

  1. SUBTYPE-SPECIFIC REGENERATION OF RETINAL GANGLION CELLS FOLLOWING AXOTOMY: EFFECTS OF OSTEOPONTIN AND MTOR SIGNALING

    PubMed Central

    Duan, Xin; Qiao, Mu; Bei, Fengfeng; Kim, In-Jung; He, Zhigang; Sanes, Joshua R.

    2015-01-01

    SUMMARY In mammals, few retinal ganglion cells (RGCs) survive following axotomy and even fewer regenerate axons. This could reflect differential extrinsic influences or the existence of subpopulations that vary in their responses to injury. We tested these alternatives by comparing responses of molecularly distinct subsets of mouse RGCs to axotomy. Survival rates varied dramatically among subtypes, with alpha-RGCs (αRGCs) surviving preferentially. Among survivors, αRGCs accounted for nearly all regeneration following down-regulation of PTEN, which activates the mTOR pathway. αRGCs have uniquely high mTOR signaling levels among RGCs and also selectively express osteopontin (OPN) and receptors for the growth factor, insulin-like growth factor 1 (IGF-1). Administration of OPN plus IGF-1 promotes regeneration as effectively as down-regulation of PTEN; however, regeneration is still confined to αRGCs. Our results reveal dramatic subtype-specific differences in the ability of RGCs to survive and regenerate following injury, and they identify promising agents for promoting axonal regeneration. PMID:25754821

  2. 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.

  3. Diffuse Traumatic Axonal Injury in the Optic Nerve Does Not Elicit Retinal Ganglion Cell Loss

    PubMed Central

    Wang, Jiaqiong; Fox, Michael A.; Povlishock, John T.

    2013-01-01

    Much of the morbidity following traumatic brain injury (TBI) is associated with traumatic axonal injury (TAI). Although most TAI studies focus on corpus callosum white matter, the visual system has received increased interest. To assess visual system TAI, we developed a mouse model of optic nerve TAI. It is unknown, however, whether this TAI causes retinal ganglion cell (RGC) death. To address this issue, YFP-16 transgenic mice were subjected to mild TBI and followed from 2 to 28 days. Neither TUNEL-positive or cleaved caspase-3 immunoreactive RGCs were observed from 2 to 28 days post-TBI. Quantification of immunoreactivity of Brn3a, an RGC marker, demonstrated no RGC loss; parallel electron microscopic analysis confirmed RGC viability. Persistent RGC survival was also consistent with the finding of reorganization in the proximal axonal segments following TAI wherein microglia/macrophages remained inactive. In contrast, activated microglia/macrophages closely enveloped the distal disconnected, degenerating axonal segments at 7 to 28 days post-injury, thereby confirming that this model consistently evoked TAI followed by disconnection. Collectively, these data provide novel insight into the evolving pathobiology associated with TAI that will form a foundation for future studies exploring TAI therapy and its downstream consequences. PMID:23860030

  4. Intestinal Neuronal Dysplasia-Like Submucosal Ganglion Cell Hyperplasia at the Proximal Margins of Hirschsprung Disease Resections

    PubMed Central

    Swaminathan, Maya; Oron, Assaf P.; Chatterjee, Sumantra; Piper, Hannah; Cope-Yokoyama, Sandy; Chakravarti, Aravinda; Kapur, Raj P.

    2016-01-01

    Intestinal neuronal dysplasia type B (IND) denotes an increased proportion of hyperplastic submucosal ganglia, as resolved histochemically in 15 µm-thick frozen sections. IND has been reported proximal to the aganglionic segment in patients with Hirschsprung disease (HSCR) and is putatively associated with a higher rate of post-surgical dysmotility. We have developed and validated histological criteria to diagnose IND-like submucosal ganglion cell hyperplasia (IND-SH) in paraffin sections, and used the approach to study the incidence and clinical/genetic associations of IND-SH at the proximal margins of HSCR pull-through resection specimens. Full-circumference paraffin sections from the proximal margins of 64 HSCR colonic pull-through specimens and 24 autopsy controls were immunostained for the neuron-specific Hu antigen and nucleated ganglion cells in each submucosal ganglion were counted. In controls, an age-related decline in the relative abundance of “giant” ganglia (≥7 nucleated Hu+ ganglion cells) was observed. A conservative diagnostic threshold for IND-SH (control mean + 3 times the standard deviation) was derived from 15 controls less than 25 weeks of age. No control exceeded this threshold, whereas in the same age range, IND-SH was observed at the proximal margins in 15% (7/46) of HSCR resections, up to 15 cm proximal to the aganglionic segment. No significant correlation was observed between IND-SH and length of or distance from the aganglionic segment, gender, trisomy 21, RET or SEMA3C/D polymorphisms, or clinical outcome, but analysis of more patients with better long-term follow-up will be required to clarify the significance of this histological phenotype. PMID:26699691

  5. Properties of somata of spinal dorsal root ganglion cells differ according to peripheral receptor innervated.

    PubMed

    Koerber, H R; Druzinsky, R E; Mendell, L M

    1988-11-01

    1. Intracellular recordings were made in the somata of dorsal root ganglion cells in the L7 or S1 DRG in cats anesthetized with alpha-chloralose. The properties of the action potentials (amplitude, duration, peak rate of rise), duration of afterhyperpolarization (AHP), magnitude of inward rectification, and axonal conduction velocity were measured. The adequate stimulus was determined, and the extent to which these properties are correlated was investigated. 2. All cells with receptive fields could be classified as mechanoreceptors. Most cells with A-beta-axons (greater than 36 m/s) could be activated by gentle mechanical stimulation but a small minority with conduction velocity in the low end of the A-beta-range were nociceptors. Cells with A-delta-axons (2-36 m/s) innervated either the very sensitive Down hair follicles (D-hairs) or high-threshold mechanoreceptors (HTMRs). In addition a group of A-delta-fibers was found for which no receptive field could be described. Their spikes, AHPs, and membrane properties were indistinguishable from those of cells supplying HTMRs (see below) and they were lumped together with A-delta-HTMRs. 3. A-beta-neurons exhibited smaller, briefer spikes than A-delta-neurons, even those supplying D-hairs. Peak rate of rise (dV/dt)max and inward rectification were significantly larger in A-beta-cells than in A-delta s, whereas AHP duration and input resistance were smaller. However, the values of these parameters in cells of a given conduction velocity range were generally associated with receptor type. 4. A-delta-HTMRs exhibited spikes of greater amplitude and duration, longer AHP duration, and smaller inward rectification than D-hairs. The long duration of these spikes was due largely to a prominent hump on their descending limb. Input resistance was similar in both groups of cells. 5. A-beta-HTMRs differed from A-beta-cells innervating low threshold receptors in the same general way that A-delta-HTMRs differed from D-hairs. However, A

  6. Development of light response and GABAergic excitation-to-inhibition switch in zebrafish retinal ganglion cells.

    PubMed

    Zhang, Rong-wei; Wei, Hong-ping; Xia, Yi-meng; Du, Jiu-lin

    2010-07-15

    The zebrafish retina has been an important model for studying morphological development of neural circuits in vivo. However, its functional development is not yet well understood. To investigate the functional development of zebrafish retina, we developed an in vivo patch-clamp whole-cell recording technique in intact zebrafish larvae. We first examined the developmental profile of light-evoked responses (LERs) in retinal ganglion cells (RGCs) from 2 to 9 days post-fertilization (dpf). Unstable LERs were first observed at 2.5 dpf. By 4 dpf, RGCs exhibited reliable light responses. As the GABAergic system is critical for retinal development, we then performed in vivo gramicidin perforated-patch whole-cell recording to characterize the developmental change of GABAergic action in RGCs. The reversal potential of GABA-induced currents (E(GABA)) in RGCs gradually shifted from depolarized to hyperpolarized levels during 2-4 dpf and the excitation-to-inhibition (E-I) switch of GABAergic action occurred at around 2.5 dpf when RGCs became light sensitive. Meanwhile, GABAergic transmission upstream to RGCs also became inhibitory by 2.5 dpf. Furthermore, down-regulation of the K(+)/Cl() co-transporter (KCC2) by the morpholino oligonucleotide-based knockdown approach, which shifted RGC E(GABA) towards a more depolarized level and thus delayed the E-I switch by one day, postponed the appearance of RGC LERs by one day. In addition, RGCs exhibited correlated giant inward current (GICs) during 2.5-3.5 dpf. The period of GICs was shifted to 3-4.5 dpf by KCC2 knockdown. Taken together, the GABAergic E-I switch occurs coincidently with the emergence of light responses and GICs in zebrafish RGCs, and may contribute to the functional development of retinal circuits.

  7. Spiral ganglion cells and macrophages initiate neuro-inflammation and scarring following cochlear implantation

    PubMed Central

    Bas, Esperanza; Goncalves, Stefania; Adams, Michelle; Dinh, Christine T.; Bas, Jose M.; Van De Water, Thomas R.; Eshraghi, Adrien A.

    2015-01-01

    Conservation of a patient's residual hearing and prevention of fibrous tissue/new bone formation around an electrode array are some of the major challenges in cochlear implant (CI) surgery. Although it is well-known that fibrotic tissue formation around the electrode array can interfere with hearing performance in implanted patients, and that associated intracochlear inflammation can initiate loss of residual hearing, little is known about the molecular and cellular mechanisms that promote this response in the cochlea. In vitro studies in neonatal rats and in vivo studies in adult mice were performed to gain insight into the pro-inflammatory, proliferative, and remodeling phases of pathological wound healing that occur in the cochlea following an electrode analog insertion. Resident Schwann cells (SC), macrophages, and fibroblasts had a prominent role in the inflammatory process in the cochlea. Leukocytes were recruited to the cochlea following insertion of a nylon filament in adult mice, where contributed to the inflammatory response. The reparative stages in wound healing are characterized by persistent neuro-inflammation of spiral ganglion neurons (SGN) and expression of regenerative monocytes/macrophages in the cochlea. Accordingly, genes involved in extracellular matrix (ECM) deposition and remodeling were up-regulated in implanted cochleae. Maturation of scar tissue occurs in the remodeling phase of wound healing in the cochlea. Similar to other damaged peripheral nerves, M2 macrophages and de-differentiated SC were observed in damaged cochleae and may play a role in cell survival and axonal regeneration. In conclusion, the insertion of an electrode analog into the cochlea is associated with robust early and chronic inflammatory responses characterized by recruitment of leukocytes and expression of pro-inflammatory cytokines that promote intracochlear fibrosis and loss of the auditory hair cells (HC) and SGN important for hearing after CI surgery. PMID

  8. Mechanisms and distribution of ion channels in retinal ganglion cells: using temperature as an independent variable.

    PubMed

    Fohlmeister, Jürgen F; Cohen, Ethan D; Newman, Eric A

    2010-03-01

    Trains of action potentials of rat and cat retinal ganglion cells (RGCs) were recorded intracellularly across a temperature range of 7-37 degrees C. Phase plots of the experimental impulse trains were precision fit using multicompartment simulations of anatomically reconstructed rat and cat RGCs. Action potential excitation was simulated with a "Five-channel model" [Na, K(delayed rectifier), Ca, K(A), and K(Ca-activated) channels] and the nonspace-clamped condition of the whole cell recording was exploited to determine the channels' distribution on the dendrites, soma, and proximal axon. At each temperature, optimal phase-plot fits for RGCs occurred with the same unique channel distribution. The "waveform" of the electrotonic current was found to be temperature dependent, which reflected the shape changes in the experimental action potentials and confirmed the channel distributions. The distributions are cell-type specific and adequate for soma and dendritic excitation with a safety margin. The highest Na-channel density was found on an axonal segment some 50-130 microm distal to the soma, as determined from the temperature-dependent "initial segment-somadendritic (IS-SD) break." The voltage dependence of the gating rate constants remains invariant between 7 and 23 degrees C and between 30 and 37 degrees C, but undergoes a transition between 23 and 30 degrees C. Both gating-kinetic and ion-permeability Q10s remain virtually constant between 23 and 37 degrees C (kinetic Q10s = 1.9-1.95; permeability Q10s = 1.49-1.64). The Q10s systematically increase for T <23 degrees C (kinetic Q10 = 8 at T = 8 degrees C). The Na channels were consistently "sleepy" (non-Arrhenius) for T <8 degrees C, with a loss of spiking for T <7 degrees C.

  9. Topoisomerase IIβ is required for lamina-specific targeting of retinal ganglion cell axons and dendrites

    PubMed Central

    Nevin, Linda M.; Xiao, Tong; Staub, Wendy; Baier, Herwig

    2011-01-01

    The specific partnering of synaptically connected neurons is central to nervous system function. Proper wiring requires the interchange of signals between a postmitotic neuron and its environment, a distinct pattern of transcription in the nucleus, and deployment of guidance and adhesion cues to the cell surface. To identify genes involved in neurite targeting by retinal ganglion cells (GCs), their presynaptic partners in the retina, and their postsynaptic targets in the optic tectum, we undertook a forward genetic screen for mutations disrupting visual responses in zebrafish. This rapid primary screen was subsequently refined by immunohistochemical labeling of retinal and tectal neurites to detect patterning errors. From this unbiased screen, the notorious (noto) mutant exhibited the most specific phenotypes: intact retinal and tectal differentiation but multiple neurite targeting defects in the retinal inner plexiform layer (IPL) and tectal neuropil. Positional cloning and morpholino phenocopy revealed that the mutation disrupts Topoisomerase IIβ (Top2b), a broadly distributed nuclear protein involved in chromatin modifications during postmitotic differentiation. Top2b-DNA interactions are known to regulate transcription of developmentally important genes, including axon guidance factors and cell adhesion molecules, but a specific role in local synaptic targeting has not been previously described. The neurite targeting defects among GC axons are largely restricted to crossovers between sublaminae of a specific layer, SFGS, and were shown by mosaic analysis to be autonomous to the GC axons. The noto mutant provides the first example of the importance of an epigenetic regulator, Top2b, in the intricate series of events that lead to a properly wired visual system. PMID:21610027

  10. 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. PMID:24993335

  11. Random Wiring, Ganglion Cell Mosaics, and the Functional Architecture of the Visual Cortex

    PubMed Central

    Coppola, David; White, Leonard E.; Wolf, Fred

    2015-01-01

    The architecture of iso-orientation domains in the primary visual cortex (V1) of placental carnivores and primates apparently follows species invariant quantitative laws. Dynamical optimization models assuming that neurons coordinate their stimulus preferences throughout cortical circuits linking millions of cells specifically predict these invariants. This might indicate that V1’s intrinsic connectome and its functional architecture adhere to a single optimization principle with high precision and robustness. To validate this hypothesis, it is critical to closely examine the quantitative predictions of alternative candidate theories. Random feedforward wiring within the retino-cortical pathway represents a conceptually appealing alternative to dynamical circuit optimization because random dimension-expanding projections are believed to generically exhibit computationally favorable properties for stimulus representations. Here, we ask whether the quantitative invariants of V1 architecture can be explained as a generic emergent property of random wiring. We generalize and examine the stochastic wiring model proposed by Ringach and coworkers, in which iso-orientation domains in the visual cortex arise through random feedforward connections between semi-regular mosaics of retinal ganglion cells (RGCs) and visual cortical neurons. We derive closed-form expressions for cortical receptive fields and domain layouts predicted by the model for perfectly hexagonal RGC mosaics. Including spatial disorder in the RGC positions considerably changes the domain layout properties as a function of disorder parameters such as position scatter and its correlations across the retina. However, independent of parameter choice, we find that the model predictions substantially deviate from the layout laws of iso-orientation domains observed experimentally. Considering random wiring with the currently most realistic model of RGC mosaic layouts, a pairwise interacting point process, the

  12. Activation of Neuropeptide Y Receptors Modulates Retinal Ganglion Cell Physiology and Exerts Neuroprotective Actions In Vitro

    PubMed Central

    Martins, João; Elvas, Filipe; Brudzewsky, Dan; Martins, Tânia; Kolomiets, Bogdan; Tralhão, Pedro; Gøtzsche, Casper R.; Cavadas, Cláudia; Castelo-Branco, Miguel; Woldbye, David P. D.; Picaud, Serge; Santiago, Ana R.

    2015-01-01

    Neuropeptide Y (NPY) is expressed in mammalian retina but the location and potential modulatory effects of NPY receptor activation remain largely unknown. Retinal ganglion cell (RGC) death is a hallmark of several retinal degenerative diseases, particularly glaucoma. Using purified RGCs and ex vivo rat retinal preparations, we have measured RGC intracellular free calcium concentration ([Ca2+]i) and RGC spiking activity, respectively. We found that NPY attenuated the increase in the [Ca2+]i triggered by glutamate mainly via Y1 receptor activation. Moreover, (Leu31, Pro34)−NPY, a Y1/Y5 receptor agonist, increased the initial burst response of OFF-type RGCs, although no effect was observed on RGC spontaneous spiking activity. The Y1 receptor activation was also able to directly modulate RGC responses by attenuating the NMDA-induced increase in RGC spiking activity. These results suggest that Y1 receptor activation, at the level of inner or outer plexiform layers, leads to modulation of RGC receptive field properties. Using in vitro cultures of rat retinal explants exposed to NMDA, we found that NPY pretreatment prevented NMDA-induced cell death. However, in an animal model of retinal ischemia-reperfusion injury, pretreatment with NPY or (Leu31, Pro34)−NPY was not able to prevent apoptosis or rescue RGCs. In conclusion, we found modulatory effects of NPY application that for the first time were detected at the level of RGCs. However, further studies are needed to evaluate whether NPY neuroprotective actions detected in retinal explants can be translated into animal models of retinal degenerative diseases. PMID:26311075

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

    PubMed Central

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

    2014-01-01

    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 PACAP. The ipRGCs regulate other non-image-forming visual functions such as the pupillary light reflex, masking behaviour 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 co-stored 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 co-localized CtB and PACAP immunostaining were identified in the SCN, the lateral geniculate complex (LGN) including the pregeniculate nucleus (PrGC), the pretectal olivary nucleus (PON), the nucleus of the optic tract (NOT), the brachium of the superior colliculus (BSC), and the superior colliculus (SC). In conclusion, PACAP immunoreactive projections with co-localized CtB represent retinal projections of ipRGCs in the macaque monkey, and support previous retrograde tracer studies demonstrating that melanopsin containing retinal projections reach areas in the primate brain involved in both image and non-image-forming visual processing. PMID:24752373

  14. Activation of Neuropeptide Y Receptors Modulates Retinal Ganglion Cell Physiology and Exerts Neuroprotective Actions In Vitro.

    PubMed

    Martins, João; Elvas, Filipe; Brudzewsky, Dan; Martins, Tânia; Kolomiets, Bogdan; Tralhão, Pedro; Gøtzsche, Casper R; Cavadas, Cláudia; Castelo-Branco, Miguel; Woldbye, David P D; Picaud, Serge; Santiago, Ana R; Ambrósio, António F

    2015-01-01

    Neuropeptide Y (NPY) is expressed in mammalian retina but the location and potential modulatory effects of NPY receptor activation remain largely unknown. Retinal ganglion cell (RGC) death is a hallmark of several retinal degenerative diseases, particularly glaucoma. Using purified RGCs and ex vivo rat retinal preparations, we have measured RGC intracellular free calcium concentration ([Ca2+]i) and RGC spiking activity, respectively. We found that NPY attenuated the increase in the [Ca2+]i triggered by glutamate mainly via Y1 receptor activation. Moreover, (Leu31, Pro34)-NPY, a Y1/Y5 receptor agonist, increased the initial burst response of OFF-type RGCs, although no effect was observed on RGC spontaneous spiking activity. The Y1 receptor activation was also able to directly modulate RGC responses by attenuating the NMDA-induced increase in RGC spiking activity. These results suggest that Y1 receptor activation, at the level of inner or outer plexiform layers, leads to modulation of RGC receptive field properties. Using in vitro cultures of rat retinal explants exposed to NMDA, we found that NPY pretreatment prevented NMDA-induced cell death. However, in an animal model of retinal ischemia-reperfusion injury, pretreatment with NPY or (Leu31, Pro34)-NPY was not able to prevent apoptosis or rescue RGCs. In conclusion, we found modulatory effects of NPY application that for the first time were detected at the level of RGCs. However, further studies are needed to evaluate whether NPY neuroprotective actions detected in retinal explants can be translated into animal models of retinal degenerative diseases.

  15. M-currents in frog sympathetic ganglion cells: manipulation of membrane phosphorylation.

    PubMed Central

    Chen, H.; Smith, P. A.

    1992-01-01

    1. The inward current and the M-current (IM) suppression produced when muscarine is applied to frog sympathetic ganglion cells was recorded by means of the whole-cell patch-clamp technique. The holding potential was -30 mV and [K+]o was 6 mM. 2. The steady-state IM was maintained for at least 20 min when the patch pipette contained neither adenosine 5'-triphosphate (ATP) nor adenosine 3':5'-cyclic monophosphate (cyclic AMP). Inclusion of these substances or the ATP antagonist, beta,gamma-methyleneadenosine 5'-triphosphate (beta,gamma-MethATP; 1 or 2 nM) (failed to alter the rate of IM 'run down'. By contrast, inclusion of adenosine-5'-O-(3-thiotriphosphate) (ATP-gamma-S, 1 or 2 mM) resulted in a 60% reduction of the current within 18 min. 3. Despite the inability of ATP-gamma-S to maintain steady-state IM, it had no effect on the ability of muscarine (2-100 microM) to suppress a constant fraction of the available current. ATP-gamma-S and beta,gamma-MethATP increased the rise time and duration of the response to muscarine. 4. Inclusion of a phosphatase inhibitor, diphosphoglyceric acid (DPG, 1-2.5 mM) or alkaline phosphatase (100 micrograms ml-1) failed to affect the amplitude of muscarinic responses. 5. These results question the role of the phosphorylation and/or dephosphorylation reactions in the transduction mechanism for muscarine-induced IM suppression but are consistent with the possibility that M-channels are 'directly coupled' via G-protein to the muscarinic receptor. PMID:1373098

  16. 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.

  17. Photopolymerized microfeatures for directed spiral ganglion neurite and Schwann cell growth

    PubMed Central

    Tuft, Bradley W.; Li, Shufeng; Xu, Linjing; Clarke, Joseph C.; White, Scott P.; Guymon, Bradley A.; Perez, Krystian X.; Hansen, Marlan R.; Guymon, C. Allan

    2015-01-01

    Cochlear implants (CIs) provide auditory perception to individuals with severe hearing impairment. However, their ability to encode complex auditory stimuli is limited due, in part, to poor spatial resolution caused by electrical current spread in the inner ear. Directing nerve cell processes towards target electrodes may reduce the problematic current spread and improve stimulatory specificity. In this work, photopolymerization was used to fabricate micro- and nano-patterned methacrylate polymers to probe the extent of spiral ganglion neuron (SGN) neurite and Schwann cell (SGSC) contact guidance based on variations in substrate topographical cues. Micropatterned substrates are formed in a rapid, single-step reaction by selectively blocking light with photomasks which have parallel line-space gratings with periodicities of 10 – 100 μm. Channel amplitudes of 250 nm – 10 μm are generated by modulating UV exposure time, light intensity, and photoinitiator concentration. Gradual transitions are observed between ridges and grooves using scanning electron and atomic force microscopy. The transitions stand in contrast to vertical features generated via etching lithographic techniques. Alignment of neural elements increases significantly with increasing feature amplitude and constant periodicity, as well as with decreasing periodicity and constant amplitude. SGN neurite alignment strongly correlates (r = 0.93) with maximum feature slope. Multiple neuronal and glial types orient to the patterns with varying degrees of alignment. This work presents a method to fabricate gradually-sloping micropatterns for cellular contact guidance studies and demonstrates spatial control of inner ear neural elements in response to micro- and nano-scale surface topography. PMID:23069708

  18. Signaling mechanism for modulation by ATP of glycine receptors on rat retinal ganglion cells

    PubMed Central

    Zhang, Ping-Ping; Zhang, Gong; Zhou, Wei; Weng, Shi-Jun; Yang, Xiong-Li; Zhong, Yong-Mei

    2016-01-01

    ATP modulates voltage- and ligand-gated channels in the CNS via the activation of ionotropic P2X and metabotropic P2Y receptors. While P2Y receptors are expressed in retinal neurons, the function of these receptors in the retina is largely unknown. Using whole-cell patch-clamp techniques in rat retinal slice preparations, we demonstrated that ATP suppressed glycine receptor-mediated currents of OFF type ganglion cells (OFF-GCs) dose-dependently, and the effect was in part mediated by P2Y1 and P2Y11, but not by P2X. The ATP effect was abolished by intracellular dialysis of a Gq/11 protein inhibitor and phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor, but not phosphatidylcholine (PC)-PLC inhibitor. The ATP effect was accompanied by an increase in [Ca2+]i through the IP3-sensitive pathway and was blocked by intracellular Ca2+-free solution. Furthermore, the ATP effect was eliminated in the presence of PKC inhibitors. Neither PKA nor PKG system was involved. These results suggest that the ATP-induced suppression may be mediated by a distinct Gq/11/PI-PLC/IP3/Ca2+/PKC signaling pathway, following the activation of P2Y1,11 and other P2Y subtypes. Consistently, ATP suppressed glycine receptor-mediated light-evoked inhibitory postsynaptic currents of OFF-GCs. These results suggest that ATP may modify the ON-to-OFF crossover inhibition, thus changing action potential patterns of OFF-GCs. PMID:27357477

  19. Random Wiring, Ganglion Cell Mosaics, and the Functional Architecture of the Visual Cortex.

    PubMed

    Schottdorf, Manuel; Keil, Wolfgang; Coppola, David; White, Leonard E; Wolf, Fred

    2015-11-01

    The architecture of iso-orientation domains in the primary visual cortex (V1) of placental carnivores and primates apparently follows species invariant quantitative laws. Dynamical optimization models assuming that neurons coordinate their stimulus preferences throughout cortical circuits linking millions of cells specifically predict these invariants. This might indicate that V1's intrinsic connectome and its functional architecture adhere to a single optimization principle with high precision and robustness. To validate this hypothesis, it is critical to closely examine the quantitative predictions of alternative candidate theories. Random feedforward wiring within the retino-cortical pathway represents a conceptually appealing alternative to dynamical circuit optimization because random dimension-expanding projections are believed to generically exhibit computationally favorable properties for stimulus representations. Here, we ask whether the quantitative invariants of V1 architecture can be explained as a generic emergent property of random wiring. We generalize and examine the stochastic wiring model proposed by Ringach and coworkers, in which iso-orientation domains in the visual cortex arise through random feedforward connections between semi-regular mosaics of retinal ganglion cells (RGCs) and visual cortical neurons. We derive closed-form expressions for cortical receptive fields and domain layouts predicted by the model for perfectly hexagonal RGC mosaics. Including spatial disorder in the RGC positions considerably changes the domain layout properties as a function of disorder parameters such as position scatter and its correlations across the retina. However, independent of parameter choice, we find that the model predictions substantially deviate from the layout laws of iso-orientation domains observed experimentally. Considering random wiring with the currently most realistic model of RGC mosaic layouts, a pairwise interacting point process, the

  20. Estimating the rate of retinal ganglion cell loss to detect glaucoma progression: An observational cohort study.

    PubMed

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

    2016-07-01

    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

  1. 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

  2. Calcium-dependent volume reduction in regenerating ganglion cell axons in vitro.

    PubMed

    Edmonds, B T; Koenig, E

    1990-06-01

    The effects of increasing [Ca2+]i on volume regulatory behavior was investigated by phase-contrast videomicroscopy in immature axons regenerating from goldfish retinal explants in vitro. Elevating [Ca2+]i by using EGTA-buffered, ionomycin-containing bathing media with either greater than or equal to 100 microM [Ca2+]o or 1 microM [Ca2+]o with N-methylglucamine substituted for Na+ caused axons to undergo a "syneresis." The syneresis was characterized by a marked loss in volume and condensation of axoplasm, accompanied by a proliferation of lateral processes, which resulted ultimately in an arrest of visible particle transport. The random appearance of dynamic phase-lucent axial protrusions in the distal axon, apparently caused by microtubules, was a frequent early manifestation. Syneresis was also produced by increasing the tonicity of the Cortland saline with sorbitol or treating axons with either valinomycin or with permeant cyclic AMP analogs in normal Cortland saline. In the latter case, extracellular Ca2+ was required. Preterminal axons showed an increase in phalloidin fluorescence after syneresis, suggesting polymerization and/or rearrangement of the actin cytoskeleton. Digitonin-permeabilized axonal field models, which maintained good morphology and particle transport, failed to develop a syneresis even when [Ca2+]o was increased to 250 microM. Cytochalasin D did not interfere with the development of a syneresis, but did suppress the proliferation of lateral processes. Syneresis could be blocked by high [K+]o, putative antagonists of Ca2(+)-activated K+ channels, or by calmidazolium, a calmodulin antagonist. The experimental findings suggest that cytoskeletal changes associated with volume reduction in growing retinal ganglion cell axons are secondary to a loss of cell water and that calcium/calmodulin-activated K+ channels very likely play a primary role in dehydration through the loss of K+ and osmotically obligated water.

  3. 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

  4. The Topographic Organization of Retinal Ganglion Cell Density and Spatial Resolving Power in an Unusual Arboreal and Slow-Moving Strepsirhine Primate, the Potto (Perodicticus potto).

    PubMed

    Coimbra, João Paulo; Kaswera-Kyamakya, Consolate; Gilissen, Emmanuel; Manger, Paul R; Collin, Shaun P

    2016-01-01

    The potto (Perodicticus potto) is an arboreal strepsirhine found in the rainforests of central Africa. In contrast to most primates, the potto shows slow-moving locomotion over the upper surface of branches, where it forages for exudates and crawling invertebrates with its head held very close to the substrate. Here, we asked whether the retina of the potto displays topographic specializations in neuronal density that correlate with its unusual lifestyle. Using stereology and retinal wholemounts, we measured the total number and topographic distribution of retinal ganglion cells (total and presumed parasol), as well as estimating the upper limits of the spatial resolution of the potto eye. We estimated ∼210,000 retinal ganglion cells, of which ∼7% (∼14,000) comprise presumed parasol ganglion cells. The topographic distribution of both total and parasol ganglion cells reveals a concentric centroperipheral organization with a nasoventral asymmetry. Combined with the upwardly shifted orbits of the potto, this nasoventral increase in parasol ganglion cell density enhances contrast sensitivity and motion detection skywards, which potentially assists with the detection of predators in the high canopy. The central area of the potto occurs ∼2.5 mm temporal to the optic disc and contains a maximum ganglion cell density of ∼4,300 cells/mm2. We found no anatomical evidence of a fovea within this region. Using maximum ganglion cell density and eye size (∼14 mm), we estimated upper limits of spatial resolving power between 4.1 and 4.4 cycles/degree. Despite their reported reliance on olfaction to detect exudates, this level of spatial resolution potentially assists pottos with foraging for small invertebrates and in the detection of predators.

  5. Comparative analysis of three purification protocols for retinal ganglion cells from rat

    PubMed Central

    Gao, Fengjuan; Li, Tingting; Hu, Jianyan; Zhou, Xujiao; Wu, Jihong

    2016-01-01

    Purpose 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. Methods 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. Results The RGC yields from the TIP, TIPM, and FC methods were 24.60±15.98 × 104, 5.28±4.42 × 104, and 5.4±2.7 × 103 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. Conclusions 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. PMID:27122968

  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. Interocular Symmetry of Macular Ganglion Cell Complex Thickness in Young Chinese Subjects

    PubMed Central

    Zhou, Minwen; Lu, Bing; Zhao, Jingke; Wang, Qiu; Zhang, Pengfei; Sun, Xiaodong

    2016-01-01

    Purpose To report interocular differences in macular ganglion cell complex (mGCC) thickness in young Chinese subjects using RTVue-100 optical coherence tomography (OCT). Methods This was an observational, cross-sectional study. The mGCC thickness was measured in 158young Chinese subjects using RTVue-100 OCT. The normal ranges of the interocular differences were determined as falling between the 2.5th and 97.5th percentiles. Right and left eyes were compared using a paired t test. Pearson correlation analysis was performed to assess the relationships between mGCC thickness and other potential factors. The relationships between the interocular difference in the average mGCC thickness and the potential factors were evaluated by univariate and multivariate linear regression analysis. Results The mean interocular difference in the average, superior, and inferior mGCC thickness were 0.19 ± 2.69 μm, 0.22 ±3.14 μm, and 0.25±3.34 μm, respectively, which were not statistically significant. The 2.5th and 97.5th percentiles of interocular difference for mean average mGCC thickness were -4.82μm and 4.38μm, for superior mGCC thickness, -6.67 μm and 7.04 μm, and for inferior mGCC thickness, -6.75 μm and 6.27 μm. There was a strong correlation between the right and left eyes for all the studied parameters, including spherical equivalent (SE) and axial length (AL). Interocular difference in SE (p = 0.007) were independently correlated with the interocular difference in average mGCC thickness. Conclusions There was no significant relative interocular difference in mGCC thickness in young Chinese subjects. Interocular difference exceeding the normal limits should be considered significantly asymmetrical, and suggestive of pathology. PMID:27454283

  8. Light and darkness regulate melanopsin in the retinal ganglion cells of the albino Wistar rat.

    PubMed

    Hannibal, Jens; Georg, Birgitte; Hindersson, Peter; Fahrenkrug, Jan

    2005-01-01

    Circadian rhythms are daily adjusted to the environmental day/night cycle by photic input via the retinohypothalamic tract (RHT). Recent studies indicate that melanopsin, a newly identified opsin-like molecule, is involved in the light responsiveness of retinal ganglion cells (RGCs) constituting the RHT. In the present study, we examined the expression of melanopsin at the mRNA and protein level during a day/night cycle and during prolonged periods of light and darkness in the retina of albino Wistar rats. We observed a diurnal change in melanopsin, with mRNA level being highest at early subjective night and protein level highest at late subjective day. Prolonged exposure to darkness significantly increased melanopsin mRNA level as early as the first day, and the expression continued to increase during 5 d in darkness. The decrease in mRNA level during exposure to constant light was slower. After 48 h of light, the melanopsin mRNA level was significantly reduced, and an almost undetectable level was found after 5 d. The induction of melanopsin by darkness was even more pronounced if darkness was preceded by light suppression for 5 d. By use of immunohistochemistry, we showed that darkness increased the amount of protein in the dendritic processes, resulting in a dense network covering the entire retina. Constant light decreased melanopsin immunostaining time dependently, beginning in the distal dendrites and progressing to the proximal dendrites and the soma. Our observations suggest that the intrinsic light-responsive RGCs adapt their expression of the putative circadian photopigment melanopsin to environmental light and darkness.

  9. Neuritin 1 promotes retinal ganglion cell survival and axonal regeneration following optic nerve crush

    PubMed Central

    Sharma, T P; Liu, Y; Wordinger, R J; Pang, I-H; Clark, A F

    2015-01-01

    Neuritin 1 (Nrn1) is an extracellular glycophosphatidylinositol-linked protein that stimulates axonal plasticity, dendritic arborization and synapse maturation in the central nervous system (CNS). The purpose of this study was to evaluate the neuroprotective and axogenic properties of Nrn1 on axotomized retinal ganglion cells (RGCs) in vitro and on the in vivo optic nerve crush (ONC) mouse model. Axotomized cultured RGCs treated with recombinant hNRN1 significantly increased survival of RGCs by 21% (n=6–7, P<0.01) and neurite outgrowth in RGCs by 141% compared to controls (n=15, P<0.05). RGC transduction with AAV2-CAG–hNRN1 prior to ONC promoted RGC survival (450%, n=3–7, P<0.05) and significantly preserved RGC function by 70% until 28 days post crush (dpc) (n=6, P<0.05) compared with the control AAV2-CAG–green fluorescent protein transduction group. Significantly elevated levels of RGC marker, RNA binding protein with multiple splicing (Rbpms; 73%, n=5–8, P<0.001) and growth cone marker, growth-associated protein 43 (Gap43; 36%, n=3, P<0.01) were observed 28 dpc in the retinas of the treatment group compared with the control group. Significant increase in Gap43 (100%, n=5–6, P<0.05) expression was observed within the optic nerves of the AAV2–hNRN1 group compared to controls. In conclusion, Nrn1 exhibited neuroprotective, regenerative effects and preserved RGC function on axotomized RGCs in vitro and after axonal injury in vivo. Nrn1 is a potential therapeutic target for CNS neurodegenerative diseases. PMID:25719245

  10. Neuritin 1 promotes retinal ganglion cell survival and axonal regeneration following optic nerve crush.

    PubMed

    Sharma, T P; Liu, Y; Wordinger, R J; Pang, I-H; Clark, A F

    2015-01-01

    Neuritin 1 (Nrn1) is an extracellular glycophosphatidylinositol-linked protein that stimulates axonal plasticity, dendritic arborization and synapse maturation in the central nervous system (CNS). The purpose of this study was to evaluate the neuroprotective and axogenic properties of Nrn1 on axotomized retinal ganglion cells (RGCs) in vitro and on the in vivo optic nerve crush (ONC) mouse model. Axotomized cultured RGCs treated with recombinant hNRN1 significantly increased survival of RGCs by 21% (n=6-7, P<0.01) and neurite outgrowth in RGCs by 141% compared to controls (n=15, P<0.05). RGC transduction with AAV2-CAG-hNRN1 prior to ONC promoted RGC survival (450%, n=3-7, P<0.05) and significantly preserved RGC function by 70% until 28 days post crush (dpc) (n=6, P<0.05) compared with the control AAV2-CAG-green fluorescent protein transduction group. Significantly elevated levels of RGC marker, RNA binding protein with multiple splicing (Rbpms; 73%, n=5-8, P<0.001) and growth cone marker, growth-associated protein 43 (Gap43; 36%, n=3, P<0.01) were observed 28 dpc in the retinas of the treatment group compared with the control group. Significant increase in Gap43 (100%, n=5-6, P<0.05) expression was observed within the optic nerves of the AAV2-hNRN1 group compared to controls. In conclusion, Nrn1 exhibited neuroprotective, regenerative effects and preserved RGC function on axotomized RGCs in vitro and after axonal injury in vivo. Nrn1 is a potential therapeutic target for CNS neurodegenerative diseases. PMID:25719245

  11. Global Gene Expression Changes in Rat Retinal Ganglion Cells in Experimental Glaucoma

    PubMed Central

    Wang, Dan Yi; Ray, Arjun; Rodgers, Kathryn; Ergorul, Ceren; Hyman, Bradley T.; Huang, Wei

    2010-01-01

    Purpose. Intraocular pressure (IOP) is an important risk factor in glaucoma. Gene expression changes were studied in glaucomatous rat retinal ganglion cells (RGCs) to elucidate altered transcriptional pathways. Methods. RGCs were back-labeled with Fluorogold. Unilateral IOP elevation was produced by injection of hypertonic saline into the episcleral veins. Laser capture microdissection (LCM) was used to capture an equal number of RGCs from normal and glaucomatous retinal sections. RNA was extracted and amplified, labeled, and hybridized to rat genome microarrays, and data analysis was performed. After selected microarray data were confirmed by RT-qPCR and immunohistochemistry, biological pathway analyses were performed. Results. Significant changes were found in the expression of 905 genes, with 330 genes increasing and 575 genes decreasing in glaucomatous RGCs. Multiple cellular pathways were involved. Ingenuity pathway analysis demonstrated significant changes in cardiac β-adrenergic signaling, interferon signaling, glutamate receptor signaling, cAMP-mediated signaling, chemokine signaling, 14-3-3-mediated signaling, and G-protein-coupled receptor signaling. Gene set enrichment analysis showed that the genes involved in apoptotic pathways were enriched in glaucomatous RGCs. The prosurvival gene Stat3 was upregulated in response to elevated IOP, and immunohistochemistry confirmed that Stat3 and phosphorylated-Stat3 levels were increased in RGCs in experimental glaucoma. In addition, the expression of several prosurvival genes normally expressed in RGCs was decreased. Conclusions. There are extensive changes in gene expression in glaucomatous RGCs involving multiple molecular pathways, including prosurvival and prodeath genes. The alteration in the balance between prosurvival and prodeath may contribute to RGC death in glaucoma. PMID:20335623

  12. 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.

  13. 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

  14. A five-primary photostimulator suitable for studying intrinsically photosensitive retinal ganglion cell functions in humans.

    PubMed

    Cao, Dingcai; Nicandro, Nathaniel; Barrionuevo, Pablo A

    2015-01-01

    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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Microparticle and Cell Characterization Using Acoustic Scattering.

    NASA Astrophysics Data System (ADS)

    Roos, Mark Schaefer

    A technique is presented for measuring physical properties of particles with radii from one to five microns. Tone bursts of 30 MHz center frequency are scattered by single particles as they are carried by a coaxial jet flow past three focused acoustic transducers (one sender and two receivers). The scattered pressure is measured simultaneously at two angles, which allows the compressibility and density of the particles to be calculated given the volume of the particles and the density and compressibility of the host liquid using Rayleigh's theory for long wavelength acoustic scattering. Because the particles are measured one at a time, statistical distributions of their properties may be determined. The device is calibrated using particles whose properties are known. A study was conducted on human red blood cells in hosts of different tonicity. Density and compressibility values obtained in these experiments are compared with a model accounting for changes in red cell properties due to variations in cell water content. Other studies were conducted using polystyrene and polystyrene divinylbenzene spheres. This technique is well suited to in vitro measurement of properties of biological cells. Applications are discussed, with emphasis on the study of red blood cells.

  20. Mechanisms and Distribution of Ion Channels in Retinal Ganglion Cells: Using Temperature as an Independent Variable

    PubMed Central

    Cohen, Ethan D.; Newman, Eric A.

    2010-01-01

    Trains of action potentials of rat and cat retinal ganglion cells (RGCs) were recorded intracellularly across a temperature range of 7–37°C. Phase plots of the experimental impulse trains were precision fit using multicompartment simulations of anatomically reconstructed rat and cat RGCs. Action potential excitation was simulated with a “Five-channel model” [Na, K(delayed rectifier), Ca, K(A), and K(Ca-activated) channels] and the nonspace-clamped condition of the whole cell recording was exploited to determine the channels' distribution on the dendrites, soma, and proximal axon. At each temperature, optimal phase-plot fits for RGCs occurred with the same unique channel distribution. The “waveform” of the electrotonic current was found to be temperature dependent, which reflected the shape changes in the experimental action potentials and confirmed the channel distributions. The distributions are cell-type specific and adequate for soma and dendritic excitation with a safety margin. The highest Na-channel density was found on an axonal segment some 50–130 μm distal to the soma, as determined from the temperature-dependent “initial segment–somadendritic (IS-SD) break.” The voltage dependence of the gating rate constants remains invariant between 7 and 23°C and between 30 and 37°C, but undergoes a transition between 23 and 30°C. Both gating-kinetic and ion-permeability Q10s remain virtually constant between 23 and 37°C (kinetic Q10s = 1.9–1.95; permeability Q10s = 1.49–1.64). The Q10s systematically increase for T <23°C (kinetic Q10 = 8 at T = 8°C). The Na channels were consistently “sleepy” (non-Arrhenius) for T <8°C, with a loss of spiking for T <7°C. PMID:20053849

  1. Glaucoma-induced degeneration of retinal ganglion cells prevented by hypoxic preconditioning: a model of glaucoma tolerance.

    PubMed

    Zhu, Yanli; Zhang, Lihong; Schmidt, Jimena F; Gidday, Jeffrey M

    2012-01-01

    Like all cells, neurons adapt to stress by transient alterations in phenotype, an epigenetic response that forms the basis for preconditioning against acute ischemic injury in the central nervous system. We recently showed that a modified repetitive hypoxic preconditioning (RHP) regimen significantly extends the window of ischemic tolerance to acute retinal ischemic injury from days to months. The present study was undertaken to determine if this uniquely protracted neuroprotective phenotype would also confer resistance to glaucomatous neurodegeneration. Retinal ganglion cell death at somatic and axonal levels was assessed after both 3 and 10 wks of sustained intraocular hypertension in an adult mouse model of inducible, open-angle glaucoma, with or without RHP before intraocular pressure elevation. Loss of brn3-positive ganglion cell soma after 3 wks of experimental glaucoma, along with increases in several apoptotic endpoints, were all significantly and robustly attenuated in mice subjected to RHP. Soma protection by RHP was also confirmed after 10 wks of intraocular hypertension by brn3 and SMI32 immunostaining. In addition, quantification of axon density in the postlaminar optic nerve documented robust preservation in RHP-treated mice, and neurofilament immunostaining also revealed preconditioning-induced improvements in axon integrity/survival in both retina and optic nerve after 10 wks of experimental glaucoma. This uniquely protracted period of phenotypic change, established in retinal ganglion cells by the activation of latent antiapoptotic, prosurvival mechanisms at both somatic and axonal levels, reflects a novel form of inducible neuronal plasticity that may provide innovative therapeutic targets for preventing and treating glaucoma and other neurodegenerative diseases. PMID:22396016

  2. AAV-mediated and pharmacological induction of Hsp70 expression stimulates survival of retinal ganglion cells following axonal injury

    PubMed Central

    Kwong, Jacky MK; Gu, Lei; Nassiri, Nariman; Bekerman, Vlad; Kumar-Singh, Rajendra; Rhee, Kun Do; Yang, Xian-Jie; Hauswirth, William W.; Caprioli, Joseph; Piri, Natik

    2014-01-01

    We evaluated the effect of AAV2- and 17-AAG (17-N -allylamino-17-demethoxygeldanamycin)-mediated upregulation of Hsp70 expression on the survival of retinal ganglion cells (RGCs) injured by optic nerve crush (ONC). AAV2-Hsp70 expression in the retina was primarily observed in the ganglion cell layer. Approximately 75% of all transfected cells were RGCs. RGC survival in AAV2-Hsp70 injected animals was increased by an average of 110% 2 weeks after the axonal injury compared to the control. The increase in cell numbers was not even across the retinas with a maximum effect of approximately 306% observed in the inferior quadrant. 17-AAG-mediated expression of Hsp70 has been associated with cell protection in various models of neurodegenerative diseases. We show here that a single intravitreal injection of 17-AAG (0.2 ug/ul) results in an increased survival of ONC injured RGCs by approximately 49% compared to the vehicle-treated animals. Expression of Hsp70 in retinas of 17-AAG-treated animals was upregulated approximately by 2-fold compared to control animals. Our data support the idea that the upregulation of Hsp70 has a beneficial effect on the survival of injured RGCs, and the induction of this protein could be viewed as a potential neuroprotective strategy for optic neuropathies. PMID:25427613

  3. Modeling the electric potential across neuronal membranes: the effect of fixed charges on spinal ganglion neurons and neuroblastoma cells.

    PubMed

    Pinto, Thiago M; Wedemann, Roseli S; Cortez, Célia M

    2014-01-01

    We present a model for the electric potential profile across the membranes of neuronal cells. We considered the resting and action potential states, and analyzed the influence of fixed charges of the membrane on its electric potential, based on experimental values of membrane properties of the spinal ganglion neuron and the neuroblastoma cell. The spinal ganglion neuron represents a healthy neuron, and the neuroblastoma cell, which is tumorous, represents a pathological neuron. We numerically solved the non-linear Poisson-Boltzmann equation for the regions of the membrane model we have adopted, by considering the densities of charges dissolved in an electrolytic solution and fixed on both glycocalyx and cytoplasmic proteins. Our model predicts that there is a difference in the behavior of the electric potential profiles of the two types of cells, in response to changes in charge concentrations in the membrane. Our results also describe an insensitivity of the neuroblastoma cell membrane, as observed in some biological experiments. This electrical property may be responsible for the low pharmacological response of the neuroblastoma to certain chemotherapeutic treatments. PMID:24801682

  4. 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.

  5. 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

  6. Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells

    PubMed Central

    Schwarz, Hans-Christoph; Kranz, Katharina; Motz, Damian; Vogt, Carla; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

    2016-01-01

    Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs), either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes. PMID:27385031

  7. Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells.

    PubMed

    Burblies, Niklas; Schulze, Jennifer; Schwarz, Hans-Christoph; Kranz, Katharina; Motz, Damian; Vogt, Carla; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

    2016-01-01

    Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs), either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes. PMID:27385031

  8. Developmental Changes in NMDA Receptor Subunit Composition at ON and OFF Bipolar Cell Synapses onto Direction-Selective Retinal Ganglion Cells

    PubMed Central

    Stafford, Benjamin K.; Park, Silvia J. H.; Wong, Kwoon Y.

    2014-01-01

    In the developing mouse retina, spontaneous and light-driven activity shapes bipolar→ganglion cell glutamatergic synapse formation, beginning around the time of eye-opening (P12–P14) and extending through the first postnatal month. During this time, glutamate release can spill outside the synaptic cleft and possibly stimulate extrasynaptic NMDA-type glutamate receptors (NMDARs) on ganglion cells. Furthermore, the role of NMDARs during development may differ between ON and OFF bipolar synapses as in mature retina, where ON synapses reportedly include extrasynaptic NMDARs with GluN2B subunits. To better understand the function of glutamatergic synapses during development, we made whole-cell recordings of NMDAR-mediated responses, in vitro, from two types of genetically identified direction-selective ganglion cells (dsGCs): TRHR (thyrotropin-releasing hormone receptor) and Drd4 (dopamine receptor 4). Both dsGC types responded to puffed NMDA between P7 and P28; and both types exhibited robust light-evoked NMDAR-mediated responses at P14 and P28 that were quantified by conductance analysis during nicotinic and GABAA receptor blockade. For a given cell type and at a given age, ON and OFF bipolar cell inputs evoked similar NMDAR-mediated responses, suggesting that ON-versus-OFF differences in mature retina do not apply to the cell types or ages studied here. At P14, puff- and light-evoked NMDAR-mediated responses in both dsGCs were partially blocked by the GluN2B antagonist ifenprodil, whereas at P28 only TRHR cells remained ifenprodil-sensitive. NMDARs contribute at both ON and OFF bipolar cell synapses during a period of robust activity-dependent synaptic development, with declining GluN2B involvement over time in specific ganglion cell types. PMID:24478373

  9. Developmental changes in NMDA receptor subunit composition at ON and OFF bipolar cell synapses onto direction-selective retinal ganglion cells.

    PubMed

    Stafford, Benjamin K; Park, Silvia J H; Wong, Kwoon Y; Demb, Jonathan B

    2014-01-29

    In the developing mouse retina, spontaneous and light-driven activity shapes bipolar→ganglion cell glutamatergic synapse formation, beginning around the time of eye-opening (P12-P14) and extending through the first postnatal month. During this time, glutamate release can spill outside the synaptic cleft and possibly stimulate extrasynaptic NMDA-type glutamate receptors (NMDARs) on ganglion cells. Furthermore, the role of NMDARs during development may differ between ON and OFF bipolar synapses as in mature retina, where ON synapses reportedly include extrasynaptic NMDARs with GluN2B subunits. To better understand the function of glutamatergic synapses during development, we made whole-cell recordings of NMDAR-mediated responses, in vitro, from two types of genetically identified direction-selective ganglion cells (dsGCs): TRHR (thyrotropin-releasing hormone receptor) and Drd4 (dopamine receptor 4). Both dsGC types responded to puffed NMDA between P7 and P28; and both types exhibited robust light-evoked NMDAR-mediated responses at P14 and P28 that were quantified by conductance analysis during nicotinic and GABA(A) receptor blockade. For a given cell type and at a given age, ON and OFF bipolar cell inputs evoked similar NMDAR-mediated responses, suggesting that ON-versus-OFF differences in mature retina do not apply to the cell types or ages studied here. At P14, puff- and light-evoked NMDAR-mediated responses in both dsGCs were partially blocked by the GluN2B antagonist ifenprodil, whereas at P28 only TRHR cells remained ifenprodil-sensitive. NMDARs contribute at both ON and OFF bipolar cell synapses during a period of robust activity-dependent synaptic development, with declining GluN2B involvement over time in specific ganglion cell types.

  10. Temporal properties of dual-peak responses of mouse retinal ganglion cells and effects of inhibitory pathways.

    PubMed

    Yan, Ru-Jia; Gong, Hai-Qing; Zhang, Pu-Ming; He, Shi-Gang; Liang, Pei-Ji

    2016-06-01

    Dual-peak responses of retinal ganglion cells (RGCs) are observed in various species, previous researches suggested that both response peaks were involved in retinal information coding. In the present study, we investigated the temporal properties of the dual-peak responses recorded in mouse RGCs elicited by spatially homogeneous light flashes and the effect of the inhibitory inputs mediated by GABAergic and/or glycinergic pathways. We found that the two peaks in the dual-peak responses exhibited distinct temporal dynamics, similar to that of short-latency and long-latency single-peak responses respectively. Pharmacological studies demonstrated that the application of exogenous GABA or glycine greatly suppressed or even eliminated the second peak of the cells' firing activities, while little change was induced in the first peak. Co-application of glycine and GABA led to complete elimination of the second peak. Moreover, application of picrotoxin or strychnine induced dual-peak responses in some cells with transient responses by unmasking a second response phase. These results suggest that both GABAergic and glycinergic pathways are involved in the dual-peak responses of the mouse RGCs, and the two response peaks may arise from distinct pathways that would converge on the ganglion cells.

  11. ATTENUATION OF THE GANGLION CELL LAYER IN A PREMATURE INFANT REVEALED WITH HANDHELD SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

    PubMed Central

    Goldberg, Mara R.; Zakka, Fouad R.; Carroll, Joseph J.

    2016-01-01

    Purpose: To report on subclinical retinal abnormalities shown through handheld spectral domain optical coherence tomography on a premature infant. Methods: Case report. Results: The initial and follow-up exams on a premature infant revealed severely attenuated ganglion cell and nerve fiber layers. There was cystoid macular edema in both eyes at the initial visits, which resolved by the 1-year follow-up. Discussion: Optical coherence tomography can reveal significant retinal abnormalities in premature infants which are not detectable through funduscopic exam. Documenting such findings may be useful for the comprehensive management of vision problems in children with a history of premature birth. PMID:26529438

  12. Overexpression of Pax6 results in microphthalmia, retinal dysplasia and defective retinal ganglion cell axon guidance

    PubMed Central

    Manuel, Martine; Pratt, Thomas; Liu, Min; Jeffery, Glen; Price, David J

    2008-01-01

    Background The transcription factor Pax6 is expressed by many cell types in the developing eye. Eyes do not form in homozygous loss-of-function mouse mutants (Pax6Sey/Sey) and are abnormally small in Pax6Sey/+ mutants. Eyes are also abnormally small in PAX77 mice expressing multiple copies of human PAX6 in addition to endogenous Pax6; protein sequences are identical in the two species. The developmental events that lead to microphthalmia in PAX77 mice are not well-characterised, so it is not clear whether over- and under-expression of Pax6/PAX6 cause microphthalmia through similar mechanisms. Here, we examined the consequences of over-expression for the eye and its axonal connections. Results Eyes form in PAX77+/+ embryos but subsequently degenerate. At E12.5, we found no abnormalities in ocular morphology, retinal cell cycle parameters and the incidence of retinal cell death. From E14.5 on, we observed malformations of the optic disc. From E16.5 into postnatal life there is progressively more severe retinal dysplasia and microphthalmia. Analyses of patterns of gene expression indicated that PAX77+/+ retinae produce a normal range of cell types, including retinal ganglion cells (RGCs). At E14.5 and E16.5, quantitative RT-PCR with probes for a range of molecules associated with retinal development showed only one significant change: a slight reduction in levels of mRNA encoding the secreted morphogen Shh at E16.5. At E16.5, tract-tracing with carbocyanine dyes in PAX77+/+ embryos revealed errors in intraretinal navigation by RGC axons, a decrease in the number of RGC axons reaching the thalamus and an increase in the proportion of ipsilateral projections among those RGC axons that do reach the thalamus. A survey of embryos with different Pax6/PAX6 gene dosage (Pax6Sey/+, Pax6+/+, PAX77+ and PAX77+/+) showed that (1) the total number of RGC axons projected by the retina and (2) the proportions that are sorted into the ipsilateral and contralateral optic tracts at the

  13. Retinal ganglion cells: mechanisms underlying depolarization block and differential responses to high frequency electrical stimulation of ON and OFF cells

    NASA Astrophysics Data System (ADS)

    Kameneva, T.; Maturana, M. I.; Hadjinicolaou, A. E.; Cloherty, S. L.; Ibbotson, M. R.; Grayden, D. B.; Burkitt, A. N.; Meffin, H.

    2016-02-01

    Objective. ON and OFF retinal ganglion cells (RGCs) are known to have non-monotonic responses to increasing amplitudes of high frequency (2 kHz) biphasic electrical stimulation. That is, an increase in stimulation amplitude causes an increase in the cell’s spike rate up to a peak value above which further increases in stimulation amplitude cause the cell to decrease its activity. The peak response for ON and OFF cells occurs at different stimulation amplitudes, which allows differential stimulation of these functional cell types. In this study, we investigate the mechanisms underlying the non-monotonic responses of ON and OFF brisk-transient RGCs and the mechanisms underlying their differential responses. Approach. Using in vitro patch-clamp recordings from rat RGCs, together with simulations of single and multiple compartment Hodgkin-Huxley models, we show that the non-monotonic response to increasing amplitudes of stimulation is due to depolarization block, a change in the membrane potential that prevents the cell from generating action potentials. Main results. We show that the onset for depolarization block depends on the amplitude and frequency of stimulation and reveal the biophysical mechanisms that lead to depolarization block during high frequency stimulation. Our results indicate that differences in transmembrane potassium conductance lead to shifts of the stimulus currents that generate peak spike rates, suggesting that the differential responses of ON and OFF cells may be due to differences in the expression of this current type. We also show that the length of the axon’s high sodium channel band (SOCB) affects non-monotonic responses and the stimulation amplitude that leads to the peak spike rate, suggesting that the length of the SOCB is shorter in ON cells. Significance. This may have important implications for stimulation strategies in visual prostheses.

  14. Tunicamycin-induced cell death in the trigeminal ganglion is suppressed by nerve growth factor in the mouse embryo.

    PubMed

    Ichikawa, Hiroyuki; Zhao, Bing-Ran; Kano, Mitsuhiro; Shimizu, Yoshinaka; Suzuki, Toshihiko; Terayama, Ruji; Matsuo, Saburo; Sugimoto, Tomosada

    2010-04-01

    The effect of nerve growth factor (NGF) on tunicamycin (Tm)-treated neurons in the trigeminal ganglion was investigated by use of caspase-3 immunohistochemistry. In intact embryos at embryonic day 16.5, only a few caspase-3-immunoreactivity were detected in the ganglion neurons. Mean +/- SE of the density of the immunoreactivity was 0.22 +/- 0.03%. In contrast, the number of the immunoreactive neurons was increased at 24 h after injection of 0.5 microg Tm in 1 microl of 0.05 N NaOH solution into mouse embryos at embryonic day 15.5. The density of immunoreactivity was also increased (mean +/- SE = 1.44 +/- 0.11%) compared to intact and 0.05 N NaOH-treated embryos (mean +/- SE = 0.35 +/- 0.03%). The Tm treatment caused increase of the number of trigeminal neurons representing apoptotic profiles (intact, mean +/- SE = 79.3 +/- 8.5; 0.05 N NaOH, mean +/- SE = 132 +/- 11.5; 0.5 microg Tm, mean +/- SE = 370.2 +/- 64.8). In addition, NGF significantly prevented the increase of density of the immunoreactivity (mean +/- SE = 0.54 +/- 0.16%) and the number of apoptotic cells (mean +/- SE = 146.2 +/- 11.3). Saline application (without NGF) had no effect on Tm-induced increase of the immunoreactivity (mean +/- SE = 1.78 +/- 0.23%) or the apoptotic profiles (mean +/- SE = 431.9 +/- 80.5). These results indicate that Tm-induced cell death in the trigeminal ganglion is suppressed by NGF in the mouse embryo.

  15. Assessment of inner retina dysfunction and progressive ganglion cell loss in a mouse model of glaucoma.

    PubMed

    Pérez de Lara, María J; Santano, Concepción; Guzmán-Aránguez, Ana; Valiente-Soriano, F Javier; Avilés-Trigueros, Marcelino; Vidal-Sanz, Manuel; de la Villa, Pedro; Pintor, Jesús

    2014-05-01

    The DBA/2J mouse is a model of ocular hypertension and retinal ganglion cell (RGC) degeneration, the main features of which are iris pigment dispersion (IPD) and iris stromal atrophy (ISA). These animals also experience glaucomatous changes, including an increase in intraocular pressure (IOP) beginning at about 9-12 months of age and sectorial RGC death in the retina. The aim of this study was to determine the onset of functional changes exhibited by DBA/2J mice in the inner retina. This was performed by means of electroretinographic recordings (scotopic threshold response, STR) and their correlation with morphological changes (loss of RGCs). To this end, we recorded the scotopic threshold response in control C57BL/6J and in DBA/2J mice at different ages. The RGCs, in both DBA/2J and C57BL/6J animals, were identified at 15 months of age by retrograde tracing with an analogue of fluorogold, hydroxystilbamidine methanesulfonate (OHSt), applied on the superior colliculi. Whole mount retinas were processed to quantify the population of RGCs identified by fluorogold tracing and Brn3a immunodetection, and were counted using image analysis software; an isodensity contour plot was generated for each retina. DBA/2J mice showed a significant reduction in the positive STR (pSTR) amplitudes at 12 months of age, as compared to control C57BL/6J mice of the same age. The pSTR mean amplitude decreased to approximately 27.82% of the values recorded in control mice (p = 0.0058). STR responses decreased in both strains as a result of the natural process of aging, but the decrease was more pronounced in DBA/2J mice. Furthermore, quantification of the total number of RGCs identified by OHSt and Brn3a expression showed a reduced population of RGCs in DBA/2J mice as compared to control mice. Regression analysis revealed significant correlations between the decrease in pSTR and a non-homogeneous reduction in the number of RGCs throughout the retina. Our results indicate the existence of

  16. 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

  17. 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

  18. Pleomorphic hyalinizing angiectatic tumor of soft parts: case report with unusual ganglion-like cells and review of the literature.

    PubMed

    Changchien, Yi-Che; Bocskai, Pál; Kovács, Ilona; Hargitai, Zoltán; Kollár, Sándor; Török, Miklós

    2014-12-01

    Pleomorphic hyalinizing angiectatic tumor (PHAT) is a recently described, non-metastasizing tumor of uncertain lineage. This tumor distributes equally between the genders and has a predilection for the subcutaneous soft tissue, particularly in lower extremity, other locations are rare. Based on the recent literature, PHAT is suspected to encompass the morphological spectrum with other tumors such as myxoinflammatory fibroblastic sarcoma (MIFS) and hemosiderotic fibrolipomatous tumor (HFLT), although cytogenetic data remain inconsistent. We report a case of PHAT that arose in the upper arm with unusual morphology which showed ganglion-like cells similar to Reed-Sternberg-like cells found in MIFS. The tumor had strong immunohistochemical expression of CD34, CD99, and was negative for S-100. The ganglion-like cells were positive for both CD34 and CD68 but negative for CD30. The translocation between chromosome 1 and 10, a frequent finding of MIFS and HFLT, was not identified by FISH excluding the possibility of hybrid PHAT and MIFS. We conclude FISH can be a potential useful tool to separate PHAT with atypical morphology from hybrid tumor in doubted cases. Due to the rarity of PHAT and lack of consistent pathogenetic signatures, more cases and further studies will be needed to elucidate the pathogenesis and nature of this tumor.

  19. Receptive Field Vectors of Genetically-Identified Retinal Ganglion Cells Reveal Cell-Type-Dependent Visual Functions

    PubMed Central

    Katz, Matthew L.; Viney, Tim J.; Nikolic, Konstantin

    2016-01-01

    Sensory stimuli are encoded by diverse kinds of neurons but the identities of the recorded neurons that are studied are often unknown. We explored in detail the firing patterns of eight previously defined genetically-identified retinal ganglion cell (RGC) types from a single transgenic mouse line. We first introduce a new technique of deriving receptive field vectors (RFVs) which utilises a modified form of mutual information (“Quadratic Mutual Information”). We analysed the firing patterns of RGCs during presentation of short duration (~10 second) complex visual scenes (natural movies). We probed the high dimensional space formed by the visual input for a much smaller dimensional subspace of RFVs that give the most information about the response of each cell. The new technique is very efficient and fast and the derivation of novel types of RFVs formed by the natural scene visual input was possible even with limited numbers of spikes per cell. This approach enabled us to estimate the 'visual memory' of each cell type and the corresponding receptive field area by calculating Mutual Information as a function of the number of frames and radius. Finally, we made predictions of biologically relevant functions based on the RFVs of each cell type. RGC class analysis was complemented with results for the cells’ response to simple visual input in the form of black and white spot stimulation, and their classification on several key physiological metrics. Thus RFVs lead to predictions of biological roles based on limited data and facilitate analysis of sensory-evoked spiking data from defined cell types. PMID:26845435

  20. Macular Ganglion Cell Imaging Study: Covariate Effects on the Spectral Domain Optical Coherence Tomography for Glaucoma Diagnosis

    PubMed Central

    Jeong, Jae Hoon; Choi, Yun Jeong; Park, Ki Ho; Kim, Dong Myung

    2016-01-01

    Purpose To evaluate the effect of multiple covariates on the diagnostic performance of the Cirrus high-definition optical coherence tomography (HD-OCT) for glaucoma detection. Methods A prospective case-control study was performed and included 173 recently diagnosed glaucoma patients and 63 unaffected individuals from the Macular Ganglion Cell Imaging Study. Regression analysis of receiver operating characteristic were conducted to evaluate the influence of age, spherical equivalent, axial length, optic disc size, and visual field index on the macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) measurements. Results Disease severity, as measured by visual field index, had a significant effect on the diagnostic performance of all Cirrus HD-OCT parameters. Age, axial length and optic disc size were significantly associated with diagnostic accuracy of average peripapillary RNFL thickness, whereas axial length had a significant effect on the diagnostic accuracy of average GCIPL thickness. Conclusions Diagnostic performance of the Cirrus HD-OCT may be more accurate in the advanced stages of glaucoma than at earlier stages. A smaller optic disc size was significantly associated with improved the diagnostic ability of average RNFL thickness measurements; however, GCIPL thickness may be less affected by age and optic disc size. PMID:27490718

  1. Retinal Ganglion Cell Atrophy in Homonymous Hemianopia due to Acquired Occipital Lesions Observed Using Cirrus High-Definition-OCT

    PubMed Central

    Yamashita, Tsutomu; Miki, Atsushi; Goto, Katsutoshi; Araki, Syunsuke; Takizawa, Go; Ieki, Yoshiaki; Kiryu, Junichi; Tabuchi, Akio; Iguchi, Yasuyuki; Kimura, Kazumi; Yagita, Yoshiki

    2016-01-01

    Purpose. To report a reduction in macular ganglion cell layer and inner plexiform layer (GCL+IPL) thickness and circumpapillary retinal nerve fiber layer (cpRNFL) thickness using spectral-domain optical coherence tomography in patients with homonymous hemianopia due to posterior cerebral artery (PCA) stroke. Methods. Seven patients with PCA stroke were examined using Cirrus high-definition-OCT. The GCL+IPL thicknesses were divided into the hemianopic and unaffected sides. The relationship between the time after stroke and the GCL+IPL thicknesses in the hemianopic side was evaluated. Results. The average thicknesses of the GCL+IPL were 64.6 and 82.0 μm on the hemianopic and unaffected sides, respectively, and the measurement was significantly thinner on the former side (p = 0.018). A regression analysis revealed a negative linear relationship (R2 = 0.574, p = 0.049) between the time after stoke and the GCL+IPL thicknesses on the hemianopic side. The supratemporal and inferotemporal cpRNFL thicknesses in the eyes ipsilateral to the stroke showed a significant reduction. Conclusion. Our findings confirmed our previous observations that the degeneration of retinal ganglion cells can occur after PCA stroke. GCL+IPL thinning was demonstrated in the hemiretinae corresponding to the affected hemifields. Also, it is suggested that the retinal changes observed are progressive. PMID:27274865

  2. Survival of ganglion cells which form the retino-retinal projection during optic nerve regeneration in the frog.

    PubMed

    Tennant, M; Bruce, S R; Beazley, L D

    1993-01-01

    During optic nerve regeneration in the frog, axons transiently grow along the opposite optic nerve forming a retino-retinal projection. In the present study, we crushed the left optic nerve in the frog Litoria (Hyla) moorei and later applied horseradish peroxidase (HRP) or diamidino yellow (DY) to the right optic nerve. In one series, retinae were examined 3 days after application of the tracer. The retino-retinal projection was found to be maximal at 5 weeks, fell significantly by 7 weeks, and returned to close-to-normal levels by 24 weeks. In a second series, we applied DY at 5 weeks as before but did not sacrifice the frogs until 7 weeks. Numbers of labeled ganglion cells were not significantly different from those frogs in the first series labeled and examined at 5 weeks. We conclude that ganglion cells giving rise to the retino-retinal projection had not died in appreciable numbers, presumably being sustained by collateral axons in the brain.

  3. 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.

  4. Retinal Ganglion Cell Atrophy in Homonymous Hemianopia due to Acquired Occipital Lesions Observed Using Cirrus High-Definition-OCT.

    PubMed

    Yamashita, Tsutomu; Miki, Atsushi; Goto, Katsutoshi; Araki, Syunsuke; Takizawa, Go; Ieki, Yoshiaki; Kiryu, Junichi; Tabuchi, Akio; Iguchi, Yasuyuki; Kimura, Kazumi; Yagita, Yoshiki

    2016-01-01

    Purpose. To report a reduction in macular ganglion cell layer and inner plexiform layer (GCL+IPL) thickness and circumpapillary retinal nerve fiber layer (cpRNFL) thickness using spectral-domain optical coherence tomography in patients with homonymous hemianopia due to posterior cerebral artery (PCA) stroke. Methods. Seven patients with PCA stroke were examined using Cirrus high-definition-OCT. The GCL+IPL thicknesses were divided into the hemianopic and unaffected sides. The relationship between the time after stroke and the GCL+IPL thicknesses in the hemianopic side was evaluated. Results. The average thicknesses of the GCL+IPL were 64.6 and 82.0 μm on the hemianopic and unaffected sides, respectively, and the measurement was significantly thinner on the former side (p = 0.018). A regression analysis revealed a negative linear relationship (R (2) = 0.574, p = 0.049) between the time after stoke and the GCL+IPL thicknesses on the hemianopic side. The supratemporal and inferotemporal cpRNFL thicknesses in the eyes ipsilateral to the stroke showed a significant reduction. Conclusion. Our findings confirmed our previous observations that the degeneration of retinal ganglion cells can occur after PCA stroke. GCL+IPL thinning was demonstrated in the hemiretinae corresponding to the affected hemifields. Also, it is suggested that the retinal changes observed are progressive. PMID:27274865

  5. Distribution of substance P-like immunoreactive retinal ganglion cells and their pattern of termination in the optic tectum of chick (Gallus gallus).

    PubMed

    Ehrlich, D; Keyser, K T; Karten, H J

    1987-12-01

    Substance P-like immunoreactive (SP-LI) neurons were identified within the inner nuclear layer and ganglion cell layer of the chick retina. The SP-LI cells in the inner nuclear layer consisted of several subtypes of neurons, differing in soma size and dendritic arborization. In the ganglion cell layer a population of moderately labelled SP-LI neurons was also present. About 6-9 microns in diameter and spaced 50-80 microns apart, they formed a regular array across the entire retina, with a density of about 400 cells/mm2 in the superior temporal retina, declining to less than 100 cells/mm2 in the peripheral retina. The total number of SP-LI cells in the ganglion cell layer was approximately 75,000. Individual axons could be followed toward the optic nerve head. Lesions near the optic nerve head resulted in axotomy of ganglion cells within a limited portion of the retina. Two days of postaxotomy there were numerous SP-LI swellings in the proximal segments of axotomized axons. SP-LI neurons in the axotomized zone were larger, more numerous, and showed increased staining of their processes. Fourteen days following a retinal lesion, there was depletion of all SP-LI cells in the ganglion cell layer within the axotomized zone, but the SP-LI neurons in the inner nuclear layer were not noticeably affected. Following a localized injection of rhodamine-coupled latex beads into the optic tectum, a population of retinal ganglion cells (RGCs) in the contralateral retina was retrogradely labelled. Many of these cells also exhibited SP-like immunoreactivity. Examination of the optic tectum indicated the presence of SP-LI fibres in laminae 2-13 (nomenclature of Cajal: Histologie du Systeme Nerveux. Vol. 2. Paris: Maloine, '11), with immunoreactive terminal regions present mainly in laminae 2-4, 7, and 9-13. SP-LI cell bodies were found predominantly in laminae 10-12 and 13. Fourteen days following a retinal lesion, SP-LI processes and terminals were depleted from laminae 2 and 3

  6. The intricacies of neurotrophic factor therapy for retinal ganglion cell rescue in glaucoma: a case for gene therapy

    PubMed Central

    Foldvari, Marianna; Chen, Ding Wen

    2016-01-01

    Regeneration of damaged retinal ganglion cells (RGC) and their axons is an important aspect of reversing vision loss in glaucoma patients. While current therapies can effectively lower intraocular pressure, they do not provide extrinsic support to RGCs to actively aid in their protection and regeneration. The unmet need could be addressed by neurotrophic factor gene therapy, where plasmid DNA, encoding neurotrophic factors, is delivered to retinal cells to maintain sufficient levels of neurotrophins in the retina. In this review, we aim to describe the intricacies in the design of the therapy including: the choice of neurotrophic factor, the site and route of administration and target cell populations for gene delivery. Furthermore, we also discuss the challenges currently being faced in RGC-related therapy development with special considerations to the existence of multiple RGC subtypes and the lack of efficient and representative in vitro models for rapid and reliable screening in the drug development process. PMID:27482199

  7. The oriented emergence of axons from retinal ganglion cells is directed by laminin contact in vivo.

    PubMed

    Randlett, Owen; Poggi, Lucia; Zolessi, Flavio R; Harris, William A

    2011-04-28

    How the site of axon emergence is specified during neural development is not understood. Previous studies disagree on the relative importance of intrinsic and extrinsic mechanisms. The axons of retinal ganglion cells (RGCs) emerge basally in vivo, yet because RGCs develop from polarized neuroepithelial cells within a polarized environment, disentangling intrinsic and extrinsic influences is a challenge. We use time-lapse imaging to demonstrate that Laminin acting directly on RGCs is necessary and sufficient to orient axon emergence in vivo. Laminin contact with the basal processes of newborn RGCs prevents the cells from entering a stochastic Stage 2 phase, directs the rapid accumulation of the early axonal marker Kif5c560-YFP, and leads to the formation of axonal growth cones. These results suggest that contact-mediated cues may be critical for the site of axon emergence and account for the differences in cellular behavior observed in vitro and in vivo.

  8. Numerical analysis of acoustic impedance microscope utilizing acoustic lens transducer to examine cultured cells.

    PubMed

    Gunawan, Agus Indra; Hozumi, Naohiro; Takahashi, Kenta; Yoshida, Sachiko; Saijo, Yoshifumi; Kobayashi, Kazuto; Yamamoto, Seiji

    2015-12-01

    A new technique is proposed for non-contact quantitative cell observation using focused ultrasonic waves. This technique interprets acoustic reflection intensity into the characteristic acoustic impedance of the biological cell. The cells are cultured on a plastic film substrate. A focused acoustic beam is transmitted through the substrate to its interface with the cell. A two-dimensional (2-D) reflection intensity profile is obtained by scanning the focal point along the interface. A reference substance is observed under the same conditions. These two reflections are compared and interpreted into the characteristic acoustic impedance of the cell based on a calibration curve that was created prior to the observation. To create the calibration curve, a numerical analysis of the sound field is performed using Fourier Transforms and is verified using several saline solutions. Because the cells are suspended by two plastic films, no contamination is introduced during the observation. In a practical observation, a sapphire lens transducer with a center frequency of 300 MHz was employed using ZnO thin film. The objects studied were co-cultured rat-derived glial (astrocyte) cells and glioma cells. The result was the clear observation of the internal structure of the cells. The acoustic impedance of the cells was spreading between 1.62 and 1.72 MNs/m(3). Cytoskeleton was indicated by high acoustic impedance. The introduction of cytochalasin-B led to a significant reduction in the acoustic impedance of the glioma cells; its effect on the glial cells was less significant. It is believed that this non-contact observation method will be useful for continuous cell inspections.

  9. Mechanism of memantine block of NMDA-activated channels in rat retinal ganglion cells: uncompetitive antagonism.

    PubMed

    Chen, H S; Lipton, S A

    1997-02-15

    1. N-methyl-D-aspartic acid (NMDA)-activated currents were recorded from dissociated rat retinal ganglion cells using whole-cell recording. The NMDA open-channel blocking drug memantine was evaluated for non-competitive and/or uncompetitive components of antagonism. A rapid superfusion system was used to apply various drugs for kinetic analysis. 2. Dose-response data revealed that memantine blocked 200 microM NMDA-evoked responses with a 50% inhibition constant (IC50) of approximately 1 microM at -60 mV and an empirical Hill coefficient of approximately 1. The antagonism followed a bimolecular reaction process. This 1:1 stoichiometry is supported by the fact that the macroscopic blocking rate of memantine (kon) increased linearly with memantine concentration and the macroscopic unblocking rate (koff) was independent of it. The estimated pseudo-first order rate constant for macroscopic blockade was 4 x 10(5) M-1 S-1 and the rate constant for unblocking was 0.44 s-1. Both the blocking and unblocking actions of memantine were well fitted by a single exponential process. 3. The kon for 2 microM memantine decreased with decreasing concentrations of NMDA. By analysing kon behaviour, we estimate that memantine has minimal interaction with the closed-unliganded state of the channel. As channel open probability (Po) approached zero, a small residual action of memantine may be explained by the presence of endogenous glutamate and glycine. 4. Memantine could be trapped within the NMDA-gated channel if it was suddenly closed by fast washout of agonist. The measured gating process of channel activation and deactivation appeared at least 10-20-fold faster than the kinetics of memantine action. By combining the agonist and voltage dependence of antagonism, a trapping scheme was established for further kinetic analysis. 5. With low agonist concentrations, NMDA-gated channels recovered slowly from memantine blockade. By analysing the probability of a channel remaining blocked, we

  10. Mechanism of memantine block of NMDA-activated channels in rat retinal ganglion cells: uncompetitive antagonism.

    PubMed Central

    Chen, H S; Lipton, S A

    1997-01-01

    1. N-methyl-D-aspartic acid (NMDA)-activated currents were recorded from dissociated rat retinal ganglion cells using whole-cell recording. The NMDA open-channel blocking drug memantine was evaluated for non-competitive and/or uncompetitive components of antagonism. A rapid superfusion system was used to apply various drugs for kinetic analysis. 2. Dose-response data revealed that memantine blocked 200 microM NMDA-evoked responses with a 50% inhibition constant (IC50) of approximately 1 microM at -60 mV and an empirical Hill coefficient of approximately 1. The antagonism followed a bimolecular reaction process. This 1:1 stoichiometry is supported by the fact that the macroscopic blocking rate of memantine (kon) increased linearly with memantine concentration and the macroscopic unblocking rate (koff) was independent of it. The estimated pseudo-first order rate constant for macroscopic blockade was 4 x 10(5) M-1 S-1 and the rate constant for unblocking was 0.44 s-1. Both the blocking and unblocking actions of memantine were well fitted by a single exponential process. 3. The kon for 2 microM memantine decreased with decreasing concentrations of NMDA. By analysing kon behaviour, we estimate that memantine has minimal interaction with the closed-unliganded state of the channel. As channel open probability (Po) approached zero, a small residual action of memantine may be explained by the presence of endogenous glutamate and glycine. 4. Memantine could be trapped within the NMDA-gated channel if it was suddenly closed by fast washout of agonist. The measured gating process of channel activation and deactivation appeared at least 10-20-fold faster than the kinetics of memantine action. By combining the agonist and voltage dependence of antagonism, a trapping scheme was established for further kinetic analysis. 5. With low agonist concentrations, NMDA-gated channels recovered slowly from memantine blockade. By analysing the probability of a channel remaining blocked, we

  11. Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro.

    PubMed

    Leitmeyer, Katharina; Glutz, Andrea; Radojevic, Vesna; Setz, Cristian; Huerzeler, Nathan; Bumann, Helen; Bodmer, Daniel; Brand, Yves

    2015-01-01

    Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.

  12. 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

  13. Distal retinal ganglion cell axon transport loss and activation of p38 MAPK stress pathway following VEGF-A antagonism

    PubMed Central

    Foxton, R; Osborne, A; Martin, K R; Ng, Y-S; Shima, D T

    2016-01-01

    There is increasing evidence that VEGF-A antagonists may be detrimental to neuronal health following ocular administration. Here we investigated firstly the effects of VEGF-A neutralization on retinal neuronal survival in the Ins2Akita diabetic and JR5558 spontaneous choroidal neovascularization (CNV) mice, and then looked at potential mechanisms contributing to cell death. We detected elevated apoptosis in the ganglion cell layer in both these models following VEGF-A antagonism, indicating that even when vascular pathologies respond to treatment, neurons are still vulnerable to reduced VEGF-A levels. We observed that retinal ganglion cells (RGCs) seemed to be the cells most susceptible to VEGF-A antagonism, so we looked at anterograde transport in these cells, due to their long axons requiring optimal protein and organelle trafficking. Using cholera toxin B-subunit tracer studies, we found a distal reduction in transport in the superior colliculus following VEGF-A neutralization, which occurred prior to net RGC loss. This phenomenon of distal transport loss has been described as a feature of early pathological changes in glaucoma, Alzheimer's and Parkinson's disease models. Furthermore, we observed increased phosphorylation of p38 MAPK and downstream Hsp27 stress pathway signaling in the retinas from these experiments, potentially providing a mechanistic explanation for our findings. These experiments further highlight the possible risks of using VEGF-A antagonists to treat ocular neovascular disease, and suggest that VEGF-A may contribute to the maintenance and function of axonal transport in neurons of the retina. PMID:27148685

  14. Distal retinal ganglion cell axon transport loss and activation of p38 MAPK stress pathway following VEGF-A antagonism.

    PubMed

    Foxton, R; Osborne, A; Martin, K R; Ng, Y-S; Shima, D T

    2016-01-01

    There is increasing evidence that VEGF-A antagonists may be detrimental to neuronal health following ocular administration. Here we investigated firstly the effects of VEGF-A neutralization on retinal neuronal survival in the Ins2(Akita) diabetic and JR5558 spontaneous choroidal neovascularization (CNV) mice, and then looked at potential mechanisms contributing to cell death. We detected elevated apoptosis in the ganglion cell layer in both these models following VEGF-A antagonism, indicating that even when vascular pathologies respond to treatment, neurons are still vulnerable to reduced VEGF-A levels. We observed that retinal ganglion cells (RGCs) seemed to be the cells most susceptible to VEGF-A antagonism, so we looked at anterograde transport in these cells, due to their long axons requiring optimal protein and organelle trafficking. Using cholera toxin B-subunit tracer studies, we found a distal reduction in transport in the superior colliculus following VEGF-A neutralization, which occurred prior to net RGC loss. This phenomenon of distal transport loss has been described as a feature of early pathological changes in glaucoma, Alzheimer's and Parkinson's disease models. Furthermore, we observed increased phosphorylation of p38 MAPK and downstream Hsp27 stress pathway signaling in the retinas from these experiments, potentially providing a mechanistic explanation for our findings. These experiments further highlight the possible risks of using VEGF-A antagonists to treat ocular neovascular disease, and suggest that VEGF-A may contribute to the maintenance and function of axonal transport in neurons of the retina. PMID:27148685

  15. 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

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

    PubMed

    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

  17. Complimentary action: C1q increases ganglion cell survival in an in vitro model of retinal degeneration.

    PubMed

    Taylor, Linnéa; Arnér, Karin; Blom, Anna M; Ghosh, Fredrik

    2016-09-15

    Using a previously described retinal explant culture system as an acute injury model, we here explore the role of C1q, the initiator of the classical complement pathway, in neuronal cell survival and retinal homeostasis. Full-thickness adult rat retinal explants were divided into four groups, receiving the following supplementation: C1q (50nM), C1-inhibitor (C1-inh; Berinert; 500mg/l), C1q+C1-inh, and no supplementation (culture controls). Explants were kept for 12h or 2days after which they were examined morphologically and with a panel of immunohistochemical markers. C1q supplementation protects ganglion cells from degeneration within the explant in vitro system. This effect is correlated to an attenuated endogenous production of C1q, and a quiesced gliotic response. PMID:27609284

  18. 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

  19. Both electrical stimulation thresholds and SMI-32-immunoreactive retinal ganglion cell density correlate with age in S334ter line 3 rat retina.

    PubMed

    Chan, Leanne L H; Lee, Eun-Jin; Humayun, Mark S; Weiland, James D

    2011-06-01

    Electrical stimulation threshold and retinal ganglion cell density were measured in a rat model of retinal degeneration. We performed in vivo electrophysiology and morphometric analysis on normal and S334ter line 3 (RD) rats (ages 84-782 days). We stimulated the retina in anesthetized animals and recorded evoked responses in the superior colliculus. Current pulses were delivered with a platinum-iridium (Pt-Ir) electrode of 75-μm diameter positioned on the epiretinal surface. In the same animals used for electrophysiology, SMI-32 immunolabeling of the retina enabled ganglion cell counting. An increase in threshold currents positively correlated with age of RD rats. SMI-32-labeled retinal ganglion cell density negatively correlated with age of RD rats. ANOVA shows that RD postnatal day (P)100 and P300 rats have threshold and density similar to normal rats, but RD P500 and P700 rats have threshold and density statistically different from normal rats (P < 0.05). Threshold charge densities were within the safety limits of Pt for all groups and pulse configurations, except at RD P600 and RD P700, where pulses were only safe up to 1- and 0.2-ms duration, respectively. Preservation of ganglion cells may enhance the efficiency and safety of electronic retinal implants.

  20. Chemogenetic Activation of Melanopsin Retinal Ganglion Cells Induces Signatures of Arousal and/or Anxiety in Mice.

    PubMed

    Milosavljevic, Nina; Cehajic-Kapetanovic, Jasmina; Procyk, Christopher A; Lucas, Robert J

    2016-09-12

    Functional imaging and psychometric assessments indicate that bright light can enhance mood, attention, and cognitive performance in humans. Indirect evidence links these events to light detection by intrinsically photosensitive melanopsin-expressing retinal ganglion cells (mRGCs) [1-9]. However, there is currently no direct demonstration that mRGCs can have such an immediate effect on mood or behavioral state in any species. We addressed this deficit by using chemogenetics to selectively activate mRGCs, simulating the excitatory effects of bright light on this cell type in dark-housed mice. This specific manipulation evoked circadian phase resetting and pupil constriction (known consequences of mRGC activation). It also induced c-Fos (a marker of neuronal activation) in multiple nuclei in the hypothalamus (paraventricular, dorsomedial, and lateral hypothalamus), thalamus (paraventricular and centromedian thalamus), and limbic system (amygdala and nucleus accumbens). These regions influence numerous aspects of autonomic and neuroendocrine activity and are typically active during periods of wakefulness or arousal. By contrast, c-Fos was absent from the ventrolateral preoptic area (active during sleep). In standard behavioral tests (open field and elevated plus maze), mRGC activation induced behaviors commonly interpreted as anxiety like or as signs of increased alertness. Similar changes in behavior could be induced by bright light in wild-type and rodless and coneless mice, but not melanopsin knockout mice. These data demonstrate that mRGCs drive a light-dependent switch in behavioral motivation toward a more alert, risk-averse state. They also highlight the ability of this small fraction of retinal ganglion cells to realign activity in brain regions defining widespread aspects of physiology and behavior. PMID:27426512

  1. Axonal degeneration, regeneration and ganglion cell death in a rodent model of anterior ischemic optic neuropathy (rAION).

    PubMed

    Zhang, Cheng; Guo, Yan; Slater, Bernard J; Miller, Neil R; Bernstein, Steven L

    2010-08-01

    Using laser-induced photoactivation of intravenously administered rose Bengal in rats, we generated an ischemic infarction of the intrascleral portion of the optic nerve (ON) comparable to that which occurs in humans to investigate optic nerve axon degenerative events following optic nerve infarct and the potential for axon re-growth. Animals were euthanized at different times post infarct. Axon degeneration was evaluated with SMI312 immunolabeling, and GAP-43 immunostaining was used to identify axon regeneration. Terminal dUTP nick end labeling (TUNEL) was used to evaluate retinal ganglion cell (RGC) death. There was significant axon structural disruptinot ion at the anterior intrascleral portion of the ON by 3d post-infarct, extending to the posterior ON by 7d post-stroke. Destruction of normal axon structure and massive loss of axon fibers occurred by 2 weeks. GAP-43 immunoreactivity occurred in the anterior ON by 7d post-infarct, lasting 3-4 weeks, without extension past the primary ischemic lesion. TUNEL-positive cells in the RGC layer appeared by 7d post-insult. These results indicate that following induction of ischemic optic neuropathy, significant axon damage occurs by 3d post-infarct, with later neuronal death. Post-stroke adult rat retinal ganglion cells attempt to regenerate their axons, but this effort is restricted to the unmyelinated region of the anterior ON. These responses are important in understanding pathologic process that underlies human non-arteritic anterior ischemic optic neuropathy (NAION) and may guide both the appropriate treatment of NAION and the window of opportunity for such treatment. PMID:20621651

  2. Chemogenetic Activation of Melanopsin Retinal Ganglion Cells Induces Signatures of Arousal and/or Anxiety in Mice.

    PubMed

    Milosavljevic, Nina; Cehajic-Kapetanovic, Jasmina; Procyk, Christopher A; Lucas, Robert J

    2016-09-12

    Functional imaging and psychometric assessments indicate that bright light can enhance mood, attention, and cognitive performance in humans. Indirect evidence links these events to light detection by intrinsically photosensitive melanopsin-expressing retinal ganglion cells (mRGCs) [1-9]. However, there is currently no direct demonstration that mRGCs can have such an immediate effect on mood or behavioral state in any species. We addressed this deficit by using chemogenetics to selectively activate mRGCs, simulating the excitatory effects of bright light on this cell type in dark-housed mice. This specific manipulation evoked circadian phase resetting and pupil constriction (known consequences of mRGC activation). It also induced c-Fos (a marker of neuronal activation) in multiple nuclei in the hypothalamus (paraventricular, dorsomedial, and lateral hypothalamus), thalamus (paraventricular and centromedian thalamus), and limbic system (amygdala and nucleus accumbens). These regions influence numerous aspects of autonomic and neuroendocrine activity and are typically active during periods of wakefulness or arousal. By contrast, c-Fos was absent from the ventrolateral preoptic area (active during sleep). In standard behavioral tests (open field and elevated plus maze), mRGC activation induced behaviors commonly interpreted as anxiety like or as signs of increased alertness. Similar changes in behavior could be induced by bright light in wild-type and rodless and coneless mice, but not melanopsin knockout mice. These data demonstrate that mRGCs drive a light-dependent switch in behavioral motivation toward a more alert, risk-averse state. They also highlight the ability of this small fraction of retinal ganglion cells to realign activity in brain regions defining widespread aspects of physiology and behavior.

  3. Histone deacetylase inhibitors sodium butyrate and valproic acid delay spontaneous cell death in purified rat retinal ganglion cells

    PubMed Central

    Boyle, Jennifer; Pielen, Amelie; Lagrèze, Wolf Alexander

    2011-01-01

    Purpose Histone deacetylase inhibitors (HDACi) have neuroprotective effects under various neurodegenerative conditions, e.g., after optic nerve crush (ONC). HDACi-mediated protection of central neurons by increased histone acetylation has not previously been demonstrated in rat retinal ganglion cells (RGCs), although epigenetic changes were shown to be associated with cell death after ONC. We investigated whether HDACi can delay spontaneous cell death in purified rat RGCs and analyzed concomitant histone acetylation levels. Methods RGCs were purified from newborn (postnatal day [P] 0–P2) rat retinas by immunopanning with antibodies against Thy-1.1 and culturing in serum-free medium for 2 days. RGCs were treated with HDACi, each at several different concentrations: 0.1–10 mM sodium butyrate (SB), 0.1–2 mM valproic acid (VPA), or 0.5–10 nM trichostatin A (TSA). Negative controls were incubated in media alone, while positive controls were incubated in 0.05–0.4 IU/µl erythropoietin. Survival was quantified by counting viable cells using phase-contrast microscopy. The expression of acetylated histone proteins (AcH) 3 and 4 was analyzed in RGCs by immunohistochemistry. Results SB and VPA enhanced RGC survival in culture, with both showing a maximum effect at 0.1 mM (increase in survival to 188% and 163%, respectively). Their neuroprotective effect was comparable to that of erythropoietin at 0.05 IU/µl. TSA 0.5–1.0 nM showed no effect on RGC survival, and concentrations ≥5 nM increased RGC death. AcH3 and AcH4 levels were only significantly increased in RGCs treated with 0.1 mM SB. VPA 0.1 mM produced only a slight effect on histone acetylation. Conclusions Millimolar concentrations of SB and VPA delayed spontaneous cell death in purified RGCs; however, significantly increased histone acetylation levels were only detectable in RGCs after SB treatment. As the potent HDACi TSA was not neuroprotective, mechanisms other than histone acetylation may be the

  4. 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. PMID:25570304

  5. Activated Müller Cells Involved in ATP-Induced Upregulation of P2X7 Receptor Expression and Retinal Ganglion Cell Death

    PubMed Central

    Xue, Ying; Xie, Yuting; Xue, Bo; Guan, Huaijin

    2016-01-01

    P2X7 receptor (P2X7R), an ATP-gated ion channel, plays an important role in glaucomatous retinal ganglion cell (RGC) apoptotic death, in which activated retinal Müller glial cells may be involved by releasing ATP. In the present study, we investigated whether and how activated Müller cells may induce changes in P2X7R expression in RGCs by using immunohistochemistry and Western blot techniques. Intravitreal injection of DHPG, a group I metabotropic glutamate receptor (mGluR I) agonist, induced upregulation of GFAP expression, suggestive of Müller cell activation (gliosis), as we previously reported. Accompanying Müller cell activation, P2X7R protein expression was upregulated, especially in the cells of ganglion cell layer (GCL), which was reversed by coinjection of brilliant blue G (BBG), a P2X7R blocker. In addition, intravitreal injection of ATP also induced upregulation of P2X7R protein expression. Similar results were observed in cultured retinal neurons by ATP treatment. Moreover, both DHPG and ATP intravitreal injection induced a reduction in the number of fluorogold retrogradely labeled RGCs, and the DHPG effect was partially rescued by coinjection of BBG. All these results suggest that activated Müller cells may release ATP and, in turn, induce upregulation of P2X7R expression in the cells of GCL, thus contributing to RGC death. PMID:27738636

  6. In vivo evaluation of an episcleral multielectrode array for stimulation of the retina with reduced retinal ganglion cell mass.

    PubMed

    Siu, Timothy L; Morley, John W

    2008-05-01

    A visual prosthesis is an experimental device designed to activate residual functional neurons in the visual pathway to generate artificial vision for blind patients. Specifically, for photoreceptor disease, a microelectrode array applied to the surface of the sclera could potentially serve to stimulate the remaining interneurons in the retina to produce topographically mapped visual percepts. However, of those neurons spared in the disease process, the retinal ganglion cells (RGC), which represent the final output neurons of the retina, can be markedly reduced in number. Using an albino rabbit model with RGC deficits, acute recording of cortical electrical evoked potential was performed to ascertain whether such a stimulation strategy is feasible. By analyzing the strength-duration curve (current threshold vs. pulse duration) and cortical activation profiles, our results prove that bioelectrically safe and spatially differentiated stimulation of the retina is feasible notwithstanding the condition of markedly reduced RGC counts.

  7. Space-time codependence of retinal ganglion cells can be explained by novel and separable components of their receptive fields.

    PubMed

    Cowan, Cameron S; Sabharwal, Jasdeep; Wu, Samuel M

    2016-09-01

    Reverse correlation methods such as spike-triggered averaging consistently identify the spatial center in the linear receptive fields (RFs) of retinal ganglion cells (GCs). However, the spatial antagonistic surround observed in classical experiments has proven more elusive. Tests for the antagonistic surround have heretofore relied on models that make questionable simplifying assumptions such as space-time separability and radial homogeneity/symmetry. We circumvented these, along with other common assumptions, and observed a linear antagonistic surround in 754 of 805 mouse GCs. By characterizing the RF's space-time structure, we found the overall linear RF's inseparability could be accounted for both by tuning differences between the center and surround and differences within the surround. Finally, we applied this approach to characterize spatial asymmetry in the RF surround. These results shed new light on the spatiotemporal organization of GC linear RFs and highlight a major contributor to its inseparability. PMID:27604400

  8. Restoring visual function to blind mice with a photoswitch that exploits electrophysiological remodeling of retinal ganglion cells

    PubMed Central

    Tochitsky, Ivan; Polosukhina, Aleksandra; Degtyar, Vadim E.; Gallerani, Nicholas; Smith, Caleb M.; Friedman, Aaron; Van Gelder, Russell N.; Trauner, Dirk; Kaufer, Daniela; Kramer, Richard H.

    2014-01-01

    Summary Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are blinding diseases caused by the degeneration of rods and cones, leaving the remainder of the visual system unable to respond to light. Here we report a chemical photoswitch named DENAQ that restores retinal responses to white light of intensity similar to ordinary daylight. A single intraocular injection of DENAQ photosensitizes the blind retina for days, restoring electrophysiological and behavioral responses with no toxicity. Experiments on mouse strains with functional, non-functional, or degenerated rods and cones show that DENAQ is effective only in retinas with degenerated photoreceptors. DENAQ confers light sensitivity on a hyperpolarization-activated inward current that is enhanced in degenerated retina, enabling optical control of retinal ganglion cell firing The acceptable light sensitivity, favorable spectral sensitivity, and selective targeting to diseased tissue make DENAQ a prime drug candidate for vision restoration in patients with end-stage RP and AMD. PMID:24559673

  9. Space-time codependence of retinal ganglion cells can be explained by novel and separable components of their receptive fields.

    PubMed

    Cowan, Cameron S; Sabharwal, Jasdeep; Wu, Samuel M

    2016-09-01

    Reverse correlation methods such as spike-triggered averaging consistently identify the spatial center in the linear receptive fields (RFs) of retinal ganglion cells (GCs). However, the spatial antagonistic surround observed in classical experiments has proven more elusive. Tests for the antagonistic surround have heretofore relied on models that make questionable simplifying assumptions such as space-time separability and radial homogeneity/symmetry. We circumvented these, along with other common assumptions, and observed a linear antagonistic surround in 754 of 805 mouse GCs. By characterizing the RF's space-time structure, we found the overall linear RF's inseparability could be accounted for both by tuning differences between the center and surround and differences within the surround. Finally, we applied this approach to characterize spatial asymmetry in the RF surround. These results shed new light on the spatiotemporal organization of GC linear RFs and highlight a major contributor to its inseparability.

  10. Light-evoked synaptic activity of retinal ganglion and amacrine cells is regulated in developing mouse retina

    PubMed Central

    He, Quanhua; Wang, Ping; Tian, Ning

    2010-01-01

    Recent studies have shown a continued maturation of visual responsiveness and synaptic activity of retina after eye opening, including the size of receptive fields of retinal ganglion cells (RGCs), light-evoked synaptic output of RGCs, bipolar cell spontaneous synaptic inputs to RGCs, and the synaptic connections between RGCs and ON and OFF bipolar cells. Light deprivation retarded some of these age-dependent changes. However, many other functional and morphological features of RGCs are not sensitive to visual experience. To determine whether light-evoked synaptic responses of RGCs undergo developmental change, we directly examined the light-evoked synaptic inputs from ON and OFF synaptic pathways to RGCs in developing retinas and found that both light-evoked excitatory and inhibitory synaptic currents decreased, but not increased, with age. We also examined the light-evoked synaptic inputs from ON and OFF synaptic pathways to amacrine cells in developing retinas and found that the light-evoked synaptic input of amacrine cells is also down-regulated in developing mouse retina. Different from the developmental changes of RGC spontaneous synaptic activity, dark rearing has little effect on the developmental changes of light-evoked synaptic activity of both RGCs and amacrine cells. Therefore, we concluded that the synaptic mechanisms mediating spontaneous and light-evoked synaptic activity of RGCs and amacrine cells are likely to be different. PMID:21091802

  11. Prevalence and Distribution of Segmentation Errors in Macular Ganglion Cell Analysis of Healthy Eyes Using Cirrus HD-OCT

    PubMed Central

    Alshareef, Rayan A.; Dumpala, Sunila; Rapole, Shruthi; Januwada, Manideepak; Goud, Abhilash; Peguda, Hari Kumar; Chhablani, Jay

    2016-01-01

    Purpose To determine the frequency of different types of spectral domain optical coherence tomography (SD-OCT) scan artifacts and errors in ganglion cell algorithm (GCA) in healthy eyes. Methods Infrared image, color-coded map and each of the 128 horizontal b-scans acquired in the macular ganglion cell-inner plexiform layer scans using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) macular cube 512 × 128 protocol in 30 healthy normal eyes were evaluated. The frequency and pattern of each artifact was determined. Deviation of the segmentation line was classified into mild (less than 10 microns), moderate (10–50 microns) and severe (more than 50 microns). Each deviation, if present, was noted as upward or downward deviation. Each artifact was further described as per location on the scan and zones in the total scan area. Results A total of 1029 (26.8%) out of total 3840 scans had scan errors. The most common scan error was segmentation error (100%), followed by degraded images (6.70%), blink artifacts (0.09%) and out of register artifacts (3.3%). Misidentification of the inner retinal layers was most frequent (62%). Upward Deviation of the segmentation line (47.91%) and severe deviation (40.3%) were more often noted. Artifacts were mostly located in the central scan area (16.8%). The average number of scans with artifacts per eye was 34.3% and was not related to signal strength on Spearman correlation (p = 0.36). Conclusions This study reveals that image artifacts and scan errors in SD-OCT GCA analysis are common and frequently involve segmentation errors. These errors may affect inner retinal thickness measurements in a clinically significant manner. Careful review of scans for artifacts is important when using this feature of SD-OCT device. PMID:27191396

  12. 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

  13. Orexin-A differentially modulates AMPA-preferring responses of ganglion cells and amacrine cells in rat retina.

    PubMed

    Zheng, Chao; Deng, Qin-Qin; Liu, Lei-Lei; Wang, Meng-Ya; Zhang, Gong; Sheng, Wen-Long; Weng, Shi-Jun; Yang, Xiong-Li; Zhong, Yong-Mei

    2015-06-01

    By activating their receptors (OX1R and OX2R) orexin-A/B regulate wake/sleeping states, feeding behaviors, but the function of these peptides in the retina remains unknown. Using patch-clamp recordings and calcium imaging in rat isolated retinal cells, we demonstrated that orexin-A suppressed α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-preferring receptor-mediated currents (AMPA-preferring currents) in ganglion cells (GCs) through OX1R, but potentiated those in amacrine cells (ACs) through OX2R. Consistently, in rat retinal slices orexin-A suppressed light-evoked AMPA-preferring receptor-mediated excitatory postsynaptic currents in GCs, but potentiated those in ACs. Intracellular dialysis of GDP-β-S or preincubation with the Gi/o inhibitor pertussis toxin (PTX) abolished both the effects. Either cAMP/the protein kinase A (PKA) inhibitor Rp-cAMP or cGMP/the PKG blocker KT5823 failed to alter the orexin-A effects. Whilst both of them involved activation of protein kinase C (PKC), the effects on GCs and ACs were respectively eliminated by the phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor and phosphatidylcholine (PC)-PLC inhibitor. Moreover, in GCs orexin-A increased [Ca(2+)]i and the orexin-A effect was blocked by intracellular Ca(2+)-free solution and by inositol 1,4,5-trisphosphate (IP3) receptor antagonists. In contrast, orexin-A did not change [Ca(2+)]i in ACs and the orexin-A effect remained in intracellular or extracellular Ca(2+)-free solution. We conclude that a distinct Gi/o/PI-PLC/IP3/Ca(2+)-dependent PKC signaling pathway, following the activation of OX1R, is likely responsible for the orexin-A effect on GCs, whereas a Gi/o/PC-PLC/Ca(2+)-independent PKC signaling pathway, following the activation of OX2R, mediates the orexin-A effect on ACs. These two actions of orexin-A, while working in concert, provide a characteristic way for modulating information processing in the inner retina.

  14. Spiral ganglion degeneration and hearing loss as a consequence of satellite cell death in saposin B-deficient mice.

    PubMed

    Akil, Omar; Sun, Ying; Vijayakumar, Sarath; Zhang, Wujuan; Ku, Tiffany; Lee, Chi-Kyou; Jones, Sherri; Grabowski, Gregory A; Lustig, Lawrence R

    2015-02-18

    Saposin B (Sap B) is an essential activator protein for arylsulfatase A in the hydrolysis of sulfatide, a lipid component of myelin. To study Sap B's role in hearing and balance, a Sap B-deficient (B(-/-)) mouse was evaluated. At both light and electron microscopy (EM) levels, inclusion body accumulation was seen in satellite cells surrounding spiral ganglion (SG) neurons from postnatal month 1 onward, progressing into large vacuoles preceding satellite cell degeneration, and followed by SG degeneration. EM also revealed reduced or absent myelin sheaths in SG neurons from postnatal month 8 onwards. Hearing loss was initially seen at postnatal month 6 and progressed thereafter for frequency-specific stimuli, whereas click responses became abnormal from postnatal month 13 onward. The progressive hearing loss correlated with the accumulation of inclusion bodies in the satellite cells and their subsequent degeneration. Outer hair cell numbers and efferent function measures (distortion product otoacoustic emissions and contralateral suppression) were normal in the B(-/-) mice throughout this period. Alcian blue staining of SGs demonstrated that these inclusion bodies corresponded to sulfatide accumulation. In contrast, changes in the vestibular system were much milder, but caused severe physiologic deficits. These results demonstrate that loss of Sap B function leads to progressive sulfatide accumulation in satellite cells surrounding the SG neurons, leading to satellite cell degeneration and subsequent SG degeneration with a resultant loss of hearing. Relative sparing of the efferent auditory and vestibular neurons suggests that alternate glycosphingolipid metabolic pathways predominate in these other systems.

  15. Excitatory Synaptic Inputs to Mouse On-Off Direction-Selective Retinal Ganglion Cells Lack Direction Tuning

    PubMed Central

    Park, Silvia J.H.; Kim, In-Jung; Looger, Loren L.

    2014-01-01

    Direction selectivity represents a fundamental visual computation. In mammalian retina, On-Off direction-selective ganglion cells (DSGCs) respond strongly to motion in a preferred direction and weakly to motion in the opposite, null direction. Electrical recordings suggested three direction-selective (DS) synaptic mechanisms: DS GABA release during null-direction motion from starburst amacrine cells (SACs) and DS acetylcholine and glutamate release during preferred direction motion from SACs and bipolar cells. However, evidence for DS acetylcholine and glutamate release has been inconsistent and at least one bipolar cell type that contacts another DSGC (On-type) lacks DS release. Here, whole-cell recordings in mouse retina showed that cholinergic input to On-Off DSGCs lacked DS, whereas the remaining (glutamatergic) input showed apparent DS. Fluorescence measurements with the glutamate biosensor intensity-based glutamate-sensing fluorescent reporter (iGluSnFR) conditionally expressed in On-Off DSGCs showed that glutamate release in both On- and Off-layer dendrites lacked DS, whereas simultaneously recorded excitatory currents showed apparent DS. With GABA-A receptors blocked, both iGluSnFR signals and excitatory currents lacked DS. Our measurements rule out DS release from bipolar cells onto On-Off DSGCs and support a theoretical model suggesting that apparent DS excitation in voltage-clamp recordings results from inadequate voltage control of DSGC dendrites during null-direction inhibition. SAC GABA release is the apparent sole source of DS input onto On-Off DSGCs. PMID:24623775

  16. Nel positively regulates the genesis of retinal ganglion cells by promoting their differentiation and survival during development

    PubMed Central

    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. PMID:24258025

  17. A comprehensive negative regulatory program controlled by Brn3b to ensure ganglion cell specification from multipotential retinal precursors.

    PubMed

    Qiu, Feng; Jiang, Haisong; Xiang, Mengqing

    2008-03-26

    The retinal ganglion cells (RGCs) are the sole output neurons in the retina that form the optic nerve and convey light signals detected by photoreceptors to the higher visual system. Their degeneration and damage caused by glaucoma and injury can lead to blindness. During retinogenesis, RGCs are specified from a population of multipotential precursors capable of generating RGC, amacrine, horizontal, and cone cells. How the RGC fate is selected from these multiple neuron fates is unknown at present. Here we show that the previously unsuspected POU domain transcription factor Brn3b (brain-specific homeobox/POU domain protein 3b) plays such a critical role. Loss of Brn3b function in mice leads to misspecification of early RGC precursors as late-born RGC, amacrine, and horizontal cells, whereas misexpressed Brn3b suppresses non-RGC cell fates but promotes the RGC fate. Microarray profiling and other molecular analyses reveal that, in RGC precursors, Brn3b normally represses the expression of a network of retinogenic factor genes involved in fate commitment and differentiation of late-born RGC, amacrine, horizontal, and cone cells. Our data suggest that Brn3b specifies the RGC fate from multipotential precursors not only by promoting RGC differentiation but also by suppressing non-RGC differentiation programs as a safeguard mechanism. PMID:18367606

  18. Neuroprotection of a Novel Cyclopeptide C*HSDGIC* from the Cyclization of PACAP (1–5) in Cellular and Rodent Models of Retinal Ganglion Cell Apoptosis

    PubMed Central

    Cheng, Huanhuan; Ding, Yong; Yu, Rongjie; Chen, Jiansu; Wu, Chunyun

    2014-01-01

    Purpose To investigate the protective effects of a novel cyclopeptide C*HSDGIC* (CHC) from the cyclization of Pituitary adenylate cyclase-activating polypeptide (PACAP) (1–5) in cellular and rodent models of retinal ganglion cell apoptosis. Methodology/Principal Findings Double-labeling immunohistochemistry was used to detect the expression of Thy-1 and PACAP receptor type 1 in a retinal ganglion cell line RGC-5. The apoptosis of RGC-5 cells was induced by 0.02 J/cm2 Ultraviolet B irradiation. MTT assay, flow cytometry, fluorescence microscopy were used to investigate the viability, the level of reactive oxygen species (ROS) and apoptosis of RGC-5 cells respectively. CHC attenuated apoptotic cell death induced by Ultraviolet B irradiation and inhibited the excessive generation of ROS. Moreover, CHC treatment resulted in decreased expression of Bax and concomitant increase of Bcl-2, as was revealed by western-blot analysis. The in vivo apoptosis of retinal ganglion cells was induced by injecting 50 mM N-methyl-D-aspartate (NMDA) (100 nmol in a 2 µL saline solution) intravitreally, and different dosages of CHC were administered. At day 7, rats in CHC+ NMDA-treated groups showed obvious aversion to light when compared to NMDA rats. Electroretinogram recordings revealed a marked decrease in the amplitudes of a-wave, b-wave, and photopic negative response due to NMDA damage. In retina receiving intravitreal NMDA and CHC co-treatment, these values were significantly increased. CHC treatment also resulted in less NMDA-induced cell loss and a decrease in the proportion of dUTP end-labeling-positive cells in ganglion cell line. Conclusions C*HSDGIC*, a novel cyclopeptide from PACAP (1–5) attenuates apoptosis in RGC-5 cells and inhibits NMDA-induced retinal neuronal death. The beneficial effects may occur via the mitochondria pathway. PACAP derivatives like CHC may serve as a promising candidate for neuroprotection in glaucoma. PMID:25286089

  19. Calbindin-immunoreactive sensory neurons in dissociated dorsal root ganglion cell cultures of chick embryo: role of culture conditions.

    PubMed

    Barakat, I; Droz, B

    1989-12-01

    Immunoreactivity to calbindin D-28k, a vitamin D-dependent calcium-binding protein, is expressed by neuronal subpopulations of dorsal root ganglia (DRG) in the chick embryo. To determine whether the expression of this phenotypic characteristic is maintained in vitro and controlled by environmental factors, dissociated DRG cell cultures were performed under various conditions. Subpopulations of DRG cells cultured at embryonic day 10 displayed calbindin-immunoreactive cell bodies and neurites in both neuron-enriched or mixed DRG cell cultures. The number of calbindin-immunoreactive ganglion cells increased up to 7-10 days of culture independently of the changes occurring in the whole neuronal population. The presence of non-neuronal cells, which promotes the maturation of the sensory neurons, tended to reduce the percentage of calbindin-immunoreactive cell bodies. Addition of horse serum enhanced both the number of calbindin-positive neurons and the intensity of the immunostaining, but does not prevent the decline of the subpopulation of calbindin-immunoreactive neurons during the second week of culture; on the contrary, the addition of muscular extract to cultures at 10 days maintained the number of calbindin-expressing neurons. While calbindin-immunoreactive cell bodies grown in culture were small- or medium-sized, no correlation was found between cell size and immunostaining density. At the ultrastructural level, the calbindin immunoreaction was distributed throughout the neuroplasm. These results indicate that the expression of calbindin by sensory neurons grown in vitro may be modulated by horse serum-contained factors or interaction with non-neuronal cells. As distinct from horse serum, muscular extract is able to maintain the expression of calbindin by a subpopulation of DRG cells.

  20. Standing surface acoustic wave (SSAW)-based cell washing

    PubMed Central

    Li, Sixing; Ding, Xiaoyun; Mao, Zhangming; Chen, Yuchao; Nama, Nitesh; Guo, Feng; Li, Peng; Wang, Lin; Cameron, Craig E.; Huang, Tony Jun

    2014-01-01

    Cell/bead washing is an indispensable sample preparation procedure used in various cell studies and analytical processes. In this article, we report a standing surface acoustic wave (SSAW)-based microfluidic device for cell and bead washing in a continuous flow. In our approach, the acoustic radiation force generated in a SSAW field is utilized to actively extract cells or beads from their original medium. A unique configuration of tilted-angle standing surface acoustic wave (taSSAW) is employed in our device, enabling us to wash beads with >98% recovery rate and >97% washing efficiency. We also demonstrate the functionality of our device by preparing high-purity (>97%) white blood cells from lysed blood samples through cell washing. Our SSAW-based cell/bead washing device has the advantages of label-free manipulation, simplicity, high biocompatibility, high recovery rate, and high washing efficiency. It can be useful for many lab-on-a-chip applications. PMID:25372273

  1. Cortical Basal Ganglionic Degeneration

    PubMed Central

    Scarmeas, Nikolaos; Chin, Steven S.; Marder, Karen

    2011-01-01

    In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a retired mason's assistant with cortical basal ganglionic degeneration (CBGD). CBGD is an extremely rare neurodegenerative disease that is categorized under both Parkinsonian syndromes and frontal lobe dementias. It affects men and women nearly equally, and the age of onset is usually in the sixth decade of life. CBGD is characterized by Parkinson's-like motor symptoms and by deficits of movement and cognition, indicating focal brain pathology. Neuronal cell loss is ultimately responsible for the neurological symptoms. PMID:14602941

  2. Functional genomic screening identifies dual leucine zipper kinase as a key mediator of retinal ganglion cell death

    PubMed Central

    Welsbie, Derek S.; Yang, Zhiyong; Ge, Yan; Mitchell, Katherine L.; Zhou, Xinrong; Martin, Scott E.; Berlinicke, Cynthia A.; Hackler, Laszlo; Fuller, John; Fu, Jie; Cao, Li-hui; Han, Bing; Auld, Douglas; Xue, Tian; Hirai, Syu-ichi; Germain, Lucie; Simard-Bisson, Caroline; Blouin, Richard; Nguyen, Judy V.; Davis, Chung-ha O.; Enke, Raymond A.; Boye, Sanford L.; Merbs, Shannath L.; Marsh-Armstrong, Nicholas; Hauswirth, William W.; DiAntonio, Aaron; Nickells, Robert W.; Inglese, James; Hanes, Justin; Yau, King-Wai; Quigley, Harry A.; Zack, Donald J.

    2013-01-01

    Glaucoma, a major cause of blindness worldwide, is a neurodegenerative optic neuropathy in which vision loss is caused by loss of retinal ganglion cells (RGCs). To better define the pathways mediating RGC death and identify targets for the development of neuroprotective drugs, we developed a high-throughput RNA interference screen with primary RGCs and used it to screen the full mouse kinome. The screen identified dual leucine zipper kinase (DLK) as a key neuroprotective target in RGCs. In cultured RGCs, DLK signaling is both necessary and sufficient for cell death. DLK undergoes robust posttranscriptional up-regulation in response to axonal injury in vitro and in vivo. Using a conditional knockout approach, we confirmed that DLK is required for RGC JNK activation and cell death in a rodent model of optic neuropathy. In addition, tozasertib, a small molecule protein kinase inhibitor with activity against DLK, protects RGCs from cell death in rodent glaucoma and traumatic optic neuropathy models. Together, our results establish a previously undescribed drug/drug target combination in glaucoma, identify an early marker of RGC injury, and provide a starting point for the development of more specific neuroprotective DLK inhibitors for the treatment of glaucoma, nonglaucomatous forms of optic neuropathy, and perhaps other CNS neurodegenerations. PMID:23431148

  3. 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. PMID:24677162

  4. Quinuclidine compounds differently act as agonists of Kenyon cell nicotinic acetylcholine receptors and induced distinct effect on insect ganglionic depolarizations.

    PubMed

    Mathé-Allainmat, Monique; Swale, Daniel; Leray, Xavier; Benzidane, Yassine; Lebreton, Jacques; Bloomquist, Jeffrey R; Thany, Steeve H

    2013-12-01

    We have recently demonstrated that a new quinuclidine benzamide compound named LMA10203 acted as an agonist of insect nicotinic acetylcholine receptors. Its specific pharmacological profile on cockroach dorsal unpaired median neurons (DUM) helped to identify alpha-bungarotoxin-insensitive nAChR2 receptors. In the present study, we tested its effect on cockroach Kenyon cells. We found that it induced an inward current demonstrating that it bounds to nicotinic acetylcholine receptors expressed on Kenyon cells. Interestingly, LMA10203-induced currents were completely blocked by the nicotinic antagonist α-bungarotoxin. We suggested that LMA10203 effect occurred through the activation of α-bungarotoxin-sensitive receptors and did not involve α-bungarotoxin-insensitive nAChR2, previously identified in DUM neurons. In addition, we have synthesized two new compounds, LMA10210 and LMA10211, and compared their effects on Kenyon cells. These compounds were members of the 3-quinuclidinyl benzamide or benzoate families. Interestingly, 1 mM LMA10210 was not able to induce an inward current on Kenyon cells compared to LMA10211. Similarly, we did not find any significant effect of LMA10210 on cockroach ganglionic depolarization, whereas these three compounds were able to induce an effect on the central nervous system of the third instar M. domestica larvae. Our data suggested that these three compounds could bind to distinct cockroach nicotinic acetylcholine receptors. PMID:23884575

  5. Isolation and Molecular Profiling of Primary Mouse Retinal Ganglion Cells: Comparison of Phenotypes from Healthy and Glaucomatous Retinas

    PubMed Central

    Chintalapudi, Sumana R.; Djenderedjian, Levon; Stiemke, Andrew B.; Steinle, Jena J.; Jablonski, Monica M.; Morales-Tirado, Vanessa M.

    2016-01-01

    Loss of functional retinal ganglion cells (RGC) is an element of retinal degeneration that is poorly understood. This is in part due to the lack of a reliable and validated protocol for the isolation of primary RGCs. Here we optimize a feasible, reproducible, standardized flow cytometry-based protocol for the isolation and enrichment of homogeneous RGC with the Thy1.2hiCD48negCD15negCD57neg surface phenotype. A three-step validation process was performed by: (1) genomic profiling of 25-genes associated with retinal cells; (2) intracellular labeling of homogeneous sorted cells for the intracellular RGC-markers SNCG, brain-specific homeobox/POU domain protein 3A (BRN3A), TUJ1, and RNA-binding protein with multiple splicing (RBPMS); and (3) by applying the methodology on RGC from a mouse model with elevated intraocular pressure (IOP) and optic nerve damage. Use of primary RGC cultures will allow for future careful assessment of important cell specific pathways in RGC to provide mechanistic insights into the declining of visual acuity in aged populations and those suffering from retinal neurodegenerative diseases. PMID:27242509

  6. 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.

  7. Immortalized Mouse Inner Ear Cell Lines Demonstrate a Role for Chemokines in Promoting the Growth of Developing Statoacoustic Ganglion Neurons

    PubMed Central

    Daruwalla, Zeeba; Roth, Therese M.; Attia, Naweah P.; Lukacs, Nicholas W.; Richards, Ayo-Lynn; White, Ian O.; Allen, Susan J.; Barald, Kate F.

    2005-01-01

    The target-derived factors necessary for promoting initial outgrowth from the statoacoustic ganglion (SAG) to the inner ear have not been fully characterized. In the present study, conditioned medium from embryonic Immortomouse inner ear cell lines that maintain many characteristics of developing inner ear sensory epithelia were screened for neurite-promoting activity. Conditioned medium found to be positive for promoting SAG neurite outgrowth and neuronal survival was then tested for the presence of chemokines, molecules that have not previously been investigated for promoting SAG outgrowth. One candidate molecule, monocyte chemotactic protein 1 (MCP-1), was detected in the conditioned medium and subsequently localized to mouse hair cells by immunocytochemistry. In vitro studies demonstrated that function-blocking MCP-1 antibodies decreased the amount of SAG neurite outgrowth induced by the conditioned medium and that subsequent addition of MCP-1 protein was able to promote outgrowth when added to the antibody-treated conditioned medium. The use of the Immortomouse cell lines proved valuable in identifying this candidate cofactor that promotes outgrowth of early-stage SAG nerve fibers and is expressed in embryonic hair cells. PMID:16240240

  8. 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.

  9. Frequency-dependent reduction of voltage-gated sodium current modulates retinal ganglion cell response rate to electrical stimulation.

    PubMed

    Tsai, David; Morley, John W; Suaning, Gregg J; Lovell, Nigel H

    2011-12-01

    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. PMID:22027396

  10. Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping

    PubMed Central

    Augustsson, Per; Karlsen, Jonas T.; Su, Hao-Wei; Bruus, Henrik; Voldman, Joel

    2016-01-01

    Mechanical phenotyping of single cells is an emerging tool for cell classification, enabling assessment of effective parameters relating to cells' interior molecular content and structure. Here, we present iso-acoustic focusing, an equilibrium method to analyze the effective acoustic impedance of single cells in continuous flow. While flowing through a microchannel, cells migrate sideways, influenced by an acoustic field, into streams of increasing acoustic impedance, until reaching their cell-type specific point of zero acoustic contrast. We establish an experimental procedure and provide theoretical justifications and models for iso-acoustic focusing. We describe a method for providing a suitable acoustic contrast gradient in a cell-friendly medium, and use acoustic forces to maintain that gradient in the presence of destabilizing forces. Applying this method we demonstrate iso-acoustic focusing of cell lines and leukocytes, showing that acoustic properties provide phenotypic information independent of size. PMID:27180912

  11. The Retina of Ansorge's Cusimanse (Crossarchus ansorgei): Number, Topography and Convergence of Photoreceptors and Ganglion Cells in Relation to Ecology and Behavior.

    PubMed

    Coimbra, João Paulo; Kaswera-Kyamakya, Consolate; Gilissen, Emmanuel; Manger, Paul R; Collin, Shaun P

    2015-01-01

    The family Herpestidae (cusimanses and mongooses) is a monophyletic radiation of carnivores with remarkable variation in microhabitat occupation and diel activity, but virtually nothing is known about how they use vision in the context of their behavioral ecology. In this paper, we measured the number and topographic distribution of neurons (rods, cones and retinal ganglion cells) and estimated the spatial resolving power of the eye of the diurnal, forest-dwelling Ansorge's cusimanse (Crossarchus ansorgei). Using retinal wholemounts and stereology, we found that rods are more numerous (42,500,000; 92%) than cones (3,900,000; 8%). Rod densities form a concentric and dorsotemporally asymmetric plateau that matches the location and shape of a bright yellow tapetum lucidum located within the dorsal aspect of the eye. Maximum rod density (340,300 cells/mm(2)) occurs within an elongated plateau below the optic disc that corresponds to a transitional region between the tapetum lucidum and the pigmented choroid. Cone densities form a temporal area with a peak density of 44,500 cells/mm(2) embedded in a weak horizontal streak that matches the topographic distribution of retinal ganglion cells. Convergence ratios of cones to retinal ganglion cells vary from 50:1 in the far periphery to 3:1 in the temporal area. With a ganglion cell peak density of 13,400 cells/mm(2) and an eye size of 11 mm in axial length, we estimated upper limits of spatial resolution of 7.5-8 cycles/degree, which is comparable to other carnivores such as hyenas. In conclusion, we suggest that the topographic retinal traits described for Ansorge's cusimanse conform to a presumed carnivore retinal blueprint but also show variations that reflect its specific ecological needs. PMID:26288092

  12. Mice with a targeted disruption of the neurotrophin receptor trkB lose their gustatory ganglion cells early but do develop taste buds.

    PubMed

    Fritzsch, B; Sarai, P A; Barbacid, M; Silos-Santiago, I

    1997-07-01

    The alleged ability of taste afferents to induce taste buds in developing animals is investigated using a mouse model with a targeted deletion of the tyrosine kinase receptor trkB for the neurotrophin BDNF. This neurotrophin was recently shown to be expressed in developing taste buds and the receptor trkB has been shown to be expressed in the developing ganglion cells that innervate the taste buds. Our data show a reduction of geniculate ganglion cells to about 5% of control animals in neonates. Degeneration of ganglion cells starts when processes reach the central target (solitary tract) but before they reach the peripheral target (taste buds). Degeneration of ganglion cells is almost completed in trkB knockout mice before taste afferents reach in control animals the developing fungiform papillae. Four days later the first taste buds can be identified in fungiform papillae of both control and trkB knockout mice in about equal number and density. Many taste buds undergo a normal maturation compared to control animals. However, the more lateral and caudal fungiform papillae grow less in size and become less conspicuous in older trkB knockout mice. No intragemmal innervation can be found in trkB knockout taste buds but a few extragemmal fibers enter the apex and end between taste had cells without forming specialized synapses. Taste buds of trkB knockout mice appear less well organized than those of control mice, but some cells show similar vesicle accumulations as control taste bud cells in their base but no synaptic contact to an afferent. These data strongly suggest that the initial-development of many fungiform papillae and taste buds is independent of the specific taste innervation. It remains to be shown why others appear to be more dependent on proper innervation. PMID:9263033

  13. Myelin-specific Th17 cells induce severe relapsing optic neuritis with irreversible loss of retinal ganglion cells in C57BL/6 mice

    PubMed Central

    Larabee, Chelsea M.; Hu, Yang; Desai, Shruti; Georgescu, Constantin; Wren, Jonathan D.; Axtell, Robert C.

    2016-01-01

    Purpose Optic neuritis affects most patients with multiple sclerosis (MS), and current treatments are unreliable. The purpose of this study was to characterize the contribution of Th1 and Th17 cells to the development of optic neuritis. Methods Mice were passively transferred myelin-specific Th1 or Th17 cells to induce experimental autoimmune encephalomyelitis (EAE), a model of neuroautoimmunity. Visual acuity was assessed daily with optokinetic tracking, and 1, 2, and 3 weeks post-induction, optic nerves and retinas were harvested for immunohistochemical analyses. Results Passive transfer experimental autoimmune encephalomyelitis elicits acute episodes of asymmetric visual deficits and is exacerbated in Th17-EAE relative to Th1-EAE. The Th17-EAE optic nerves contained more inflammatory infiltrates and an increased neutrophil to macrophage ratio. Significant geographic degeneration of the retinal ganglion cells accompanied Th17-EAE but not Th1. Conclusions Th17-induced transfer EAE recapitulates pathologies observed in MS-associated optic neuritis, namely, monocular episodes of vision loss, optic nerve inflammation, and geographic retinal ganglion cell (RGC) degeneration. PMID:27122964

  14. 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

  15. Investigating the expression of metabotropic glutamate receptors in trigeminal ganglion neurons and satellite glial cells: implications for craniofacial pain

    PubMed Central

    Boye Larsen, Dennis; Ingemann Kristensen, Gunda; Panchalingam, Vinodenee; Laursen, Jens Christian; Nørgaard Poulsen, Jeppe; Skallerup Andersen, Maria; Kandiah, Aginsha

    2014-01-01

    Context/objective Previous studies have demonstrated that various subtypes of the metabotropic glutamate receptors (mGluRs) are expressed in the dorsal root ganglion (DRG) of the peripheral nervous system (PNS), implicating that glutamate potentially contributes to sensory transmission through these receptors. While mGluR expression has been investigated largely in the DRG, the present study focused on mGluR expression on neurons and satellite glial cells (SGCs) of the trigeminal ganglion (TG). Materials and methods: To address the presence of mGluRs in rat TG neurons and their corresponding SGCs, the trigeminal ganglia from six adult male Wistar rats were isolated and immunohistochemistry and immunocytochemistry were performed. The expression of mGluR1α-, mGluR2/3- and mGluR8 on TG neurons and SGCs was investigated in tissue slices and isolated cells. Results: 35.1 ± 6.0% of the TG neurons were positive for mGluR1α, whereas 39.9 ± 7.7% and 55.5 ± 6.3% were positive for mGluR2/3 and mGluR8, respectively. Immunoreactive neurons expressing mGluRs were mainly medium- to large sized, with a smaller population of small-sized neurons showing immunoreactivity. The SGCs showed immunoreactivity toward mGluR1α and mGluR8, but not mGluR2/3, both in the tissue and in isolated cells. Conclusions: Findings from the present study showed that trigeminal neurons express mGluR1α, mGluR2/3 and mGluR8, while SGCs only express mGluR1α and mGluR8. This novel evidence may advance investigations on a possible role of mGluRs in relation to trigeminal pain transmission within the craniofacial region. PMID:24495291

  16. Distribution of damage to the entire retinal ganglion cell pathway: quantified using spectral-domain optical coherence tomography analysis in patients with glaucoma.

    PubMed

    Lee, Kyungmoo; Kwon, Young H; Garvin, Mona K; Niemeijer, Meindert; Sonka, Milan; Abràmoff, Michael D

    2012-09-01

    OBJECTIVES To test the hypothesis that the amount and distribution of glaucomatous damage along the entire retinal ganglion cell-axonal complex (RGC-AC) can be quantified and to map the RGC-AC connectivity in early glaucoma using automated image analysis of standard spectral-domain optical coherence tomography. METHODS Spectral-domain optical coherence tomography volumes were obtained from 116 eyes in 58 consecutive patients with glaucoma or suspected glaucoma. Layer and optic nerve head (ONH) analysis was performed; the mean regional retinal ganglion cell layer thickness (68 regions), nerve fiber layer (NFL) thickness (120 regions), and ONH rim area (12 wedge-shaped regions) were determined. Maps of RGC-AC connectivity were created using maximum correlation between regions' ganglion cell layer thickness, NFL thickness, and ONH rim area; for retinal nerve fiber bundle regions, the maximum "thickness correlation paths" were determined. RESULTS The mean (SD) NFL thickness and ganglion cell layer thickness across all macular regions were 22.5 (7.5) μm and 33.9 (8.4) μm, respectively. The mean (SD) rim area across all ONH wedge regions was 0.038 (0.004) mm2. Connectivity maps were obtained successfully and showed typical nerve fiber bundle connectivity of the RGC-AC cell body segment to the initial NFL axonal segment, of the initial to the final RGC-AC NFL axonal segments, of the final RGC-AC NFL axonal to the ONH axonal segment, and of the RGC-AC cell body segment to the ONH axonal segment. CONCLUSIONS In early glaucoma, the amount and distribution of glaucomatous damage along the entire RGC-AC can be quantified and mapped using automated image analysis of standard spectral-domain optical coherence tomography. Our findings should contribute to better detection and improved management of glaucoma. PMID:22965586

  17. Glial cell line-derived neurotrophic factor (GDNF) induces neuritogenesis in the cochlear spiral ganglion via neural cell adhesion molecule (NCAM).

    PubMed

    Euteneuer, Sara; Yang, Kuo H; Chavez, Eduardo; Leichtle, Anke; Loers, Gabriele; Olshansky, Adel; Pak, Kwang; Schachner, Melitta; Ryan, Allen F

    2013-05-01

    Glial cell line-derived neurotrophic factor (GDNF) increases survival and neurite extension of spiral ganglion neurons (SGNs), the primary neurons of the auditory system, via yet unknown signaling mechanisms. In other cell types, signaling is achieved by the GPI-linked GDNF family receptor α1 (GFRα1) via recruitment of transmembrane receptors: Ret (re-arranged during transformation) and/or NCAM (neural cell adhesion molecule). Here we show that GDNF enhances neuritogenesis in organotypic cultures of spiral ganglia from 5-day-old rats and mice. Addition of GFRα1-Fc increases this effect. GDNF/GFRα1-Fc stimulation activates intracellular PI3K/Akt and MEK/Erk signaling cascades as detected by Western blot analysis of cultures prepared from rats at postnatal days 5 (P5, before the onset of hearing) and 20 (P20, after the onset of hearing). Both cascades mediate GDNF stimulation of neuritogenesis, since application of the Akt inhibitor Wortmannin or the Erk inhibitor U0126 abolished GDNF/GFRα1-Fc stimulated neuritogenesis in P5 rats. Since cultures of P5 NCAM-deficient mice failed to respond by neuritogenesis to GDNF/GFRα1-Fc, we conclude that NCAM serves as a receptor for GDNF signaling responsible for neuritogenesis in early postnatal spiral ganglion.

  18. Inflammatory demyelination induces glia alterations and ganglion cell loss in the retina of an experimental autoimmune encephalomyelitis model

    PubMed Central

    2013-01-01

    Background Multiple sclerosis (MS) is often accompanied by optic nerve inflammation. And some patients experience permanent vision loss. We examined if the grade of optic nerve infiltration and demyelination affects the severity of clinical signs in an experimental autoimmune encephalomyelitis (EAE) model. The loss of retinal ganglion cells (RGC) and alterations in glia activity were also investigated. Methods C57BL/6 mice were immunized with peptide MOG35-55 in complete Freund’s adjuvant (CFA) and controls received PBS in CFA. Then 23 days post immunization eyes were prepared for flatmounts and stained with Nissl to evaluated neuronal density. Clinical EAE symptoms as well as cell infiltration and demyelination in the optic nerve were examined. Retinal sections were stained with hematoxylin and eosin and silver stain. Immunohistochemistry was used to label RGCs (Brn-3a), apoptotic cells (caspase 3), macroglia (glial fibrillary acidic protein (GFAP)), microglia (Iba1), macrophages (F 4/80) and interleukin-6 (IL-6) secretion. Results EAE symptoms started at day 8 and peaked at day 15. Cell infiltrations (P = 0.0047) and demyelination (P = 0.0018) of EAE nerves correlated with the clinical score (r > 0.8). EAE led to a significant loss of RGCs (P< 0.0001). Significantly more caspase 3+ cells were noted in these animals (P = 0.0222). They showed an increased expression of GFAP (P< 0.0002) and a higher number of microglial cells (P< 0.0001). Also more macrophages and IL-6 secretion were observed in EAE mice. Conclusions MOG immunization leads to optic neuritis and RGC loss. EAE severity is related to the severity of optic nerve inflammation and demyelination. EAE not only affects activation of apoptotic signals, but also causes a glial response in the retina. PMID:24090415

  19. Increased production of omega-3 fatty acids protects retinal ganglion cells after optic nerve injury in mice.

    PubMed

    Peng, Shanshan; Shi, Zhe; Su, Huanxing; So, Kwok-Fai; Cui, Qi

    2016-07-01

    Injury to the central nervous system causes progressive degeneration of injured axons, leading to loss of the neuronal bodies. Neuronal survival after injury is a prerequisite for successful regeneration of injured axons. In this study, we investigated the effects of increased production of omega-3 fatty acids and elevation of cAMP on retinal ganglion cell (RGC) survival and axonal regeneration after optic nerve (ON) crush injury in adult mice. We found that increased production of omega-3 fatty acids in mice enhanced RGC survival, but not axonal regeneration, over a period of 3 weeks after ON injury. cAMP elevation promoted RGC survival in wild type mice, but no significant difference in cell survival was seen in mice over-producing omega-3 fatty acids and receiving intravitreal injections of CPT-cAMP, suggesting that cAMP elevation protects RGCs after injury but does not potentiate the actions of the omega-3 fatty acids. The observed omega-3 fatty acid-mediated neuroprotection is likely achieved partially through ERK1/2 signaling as inhibition of this pathway by PD98059 hindered, but did not completely block, RGC protection. Our study thus enhances our current understanding of neural repair after CNS injury, including the visual system.

  20. 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.

  1. 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

  2. The three faces of vestibular ganglionitis.

    PubMed

    Gacek, Richard R; Gacek, Mark R

    2002-02-01

    We present temporal bone and clinical evidence that common syndromes of recurrent vertigo are caused by a viral infection of the vestibular ganglion. In the present series, histopathologic and radiologic changes in the vestibular ganglion and meatal ganglion were consistent with a viral inflammation of ganglion cells in cases of Meniere's disease, benign paroxysmal positional vertigo, and vestibular neuronitis. Clinical observations of multiple neuropathies involving cranial nerves V, VII, and VIII on the same side in patients with recurrent vertigo are best explained by a cranial polyganglionitis caused by a neurotrophic virus, which is reactivated by a stressful event later in life. The reactivation of the latent virus may manifest as one of the above vertigo syndromes, depending on the part of the vestibular ganglion that is inflamed, the type and strain of the virus, and host resistance.

  3. Deformation of red blood cells using acoustic radiation forces

    PubMed Central

    Mishra, Puja; Hill, Martyn; Glynne-Jones, Peter

    2014-01-01

    Acoustic radiation forces have been used to manipulate cells and bacteria in a number of recent microfluidic applications. The net force on a cell has been subject to careful investigation over a number of decades. We demonstrate that the radiation forces also act to deform cells. An ultrasonic standing wave field is created in a 0.1 mm glass capillary at a frequency of 7.9 MHz. Using osmotically swollen red-blood cells, we show observable deformations up to an aspect ratio of 1.35, comparable to deformations created by optical tweezing. In contrast to optical technologies, ultrasonic devices are potentially capable of deforming thousands of cells simultaneously. We create a finite element model that includes both the acoustic environment of the cell, and a model of the cell membrane subject to forces resulting from the non-linear aspects of the acoustic field. The model is found to give reasonable agreement with the experimental results, and shows that the deformation is the result of variation in an acoustic force that is directed outwards at all points on the cell membrane. We foresee applications in diagnostic devices, and in the possibility of mechanically stimulating cells to promote differentiation and physiological effects. PMID:25379070

  4. Inhibiting Matrix Metalloproteinase 3 Ameliorates Neuronal Loss in the Ganglion Cell Layer of Rats in Retinal Ischemia/Reperfusion.

    PubMed

    Hu, Tu; You, Qiuting; Chen, Dan; Tong, Jianbin; Shang, Lei; Luo, Jia; Qiu, Yi; Yu, Huimin; Zeng, Leping; Huang, Jufang

    2016-05-01

    It has been demonstrated that matrix metalloproteinase 3 (MMP3) is integrally involved in the neuronal degeneration of the central nervous system by promoting glial activation, neuronal apoptosis and damage to the brain-blood barrier. However, whether MMP3 also contributes to the neuronal degeneration induced by retinal ischemia/reperfusion is still uncertain. In the present study, we detected the cellular localization of MMP3 in adult rat retinae and explored the relationship of its expression with neuronal loss in the ganglion cell layer (GCL) in retinal ischemia/reperfusion. We found that MMP3 was widely expressed in many cells throughout the layers of the rat retinae, including Vertebrate neuron-specific nuclear protein (NeuN)-, parvalbumin-, calbindin-, protein kinase C-α-, glial fibrillary acidic protein-, glutamine synthetase- and CD11b-positive cells. Furthermore, all rats were treated with high intraocular pressure (HIOP) for 1 h (h) and sacrificed at 6 h, 1 day (d), 3 d, and 7 d after HIOP. Compared to the normal control, the expression of both proenzyme MMP3 and active MMP3 were significantly up-regulated after HIOP treatment without alteration of the laminar distribution pattern. Moreover, inhibiting MMP3 ameliorated the loss of NeuN-positive cells in the GCL following HIOP. In summary, our data demonstrates that MMP3 is expressed in multiple types of neurons and glial cells in normal rat retinae. Simultaneously, the up-regulation of its expression and activity are closely involved in neuronal loss in the GCL in retinal ischemia/reperfusion. PMID:26830289

  5. Effect of Distance and Duration of Illumination on Retinal Ganglion Cells Exposed to Varying Concentrations of Brilliant Blue Green

    PubMed Central

    Chalam, Kakarla V.; Li, Wenhua; Koushan, Keyvan; Grover, Sandeep; Balaiya, Sankarathi

    2015-01-01

    Background The objective of the study was to determine the safety parameters of using brilliant blue green (BBG) for chromovitrectomy by assessing the cytotoxicity of BBG on cultured retinal ganglion cells (RGCs) exposed to illumination. Methods RGCs were exposed to two concentrations of BBG (0.25 and 0.5 mg/mL) under metal halide illumination at varying distances (1 and 2.5 cm), intensities (990 and 2,000 Fc), and durations (1, 5 and 15 minutes). Cell viability was assessed using the WST-1 and CellTiter 96® AQueous One solution cell proliferation assays. Results Using the WST-1 assay, with high-intensity illumination, viability of RGCs ranged from 97.5±16.4% of controls with minimum BBG and light exposure (0.25 mg/mL BBG and illuminated for 1 minute at 2.5 cm distance) to 53.1±11.3% of controls with maximum BBG and light exposure (0.50 mg/mL and illuminated for 15 minutes at 1 cm distance; P < 0.01). With medium-intensity illumination, RGCs showed better viability, ranging from 95.1±7.2% of controls with minimum BBG and light exposure to 72.3±12.8% of controls with maximum BBG and light exposure. CellTiter 96® AQueous One assay showed similar results. Conclusion RGCs seem to safely tolerate up to 5 minutes of exposure to 0.5 mg/mL BBG under diffuse medium-intensity illumination (990 Fc). PMID:26015816

  6. 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.

  7. No influence of acute RF exposure (GSM-900, GSM-1800, and UMTS) on mouse retinal ganglion cell responses under constant temperature conditions.

    PubMed

    Ahlers, Malte T; Ammermüller, Josef

    2014-01-01

    Possible non-thermal effects of radio frequency electromagnetic fields (RF-EMF) on retinal ganglion cells were studied in vitro under conditions of constant temperature. Isolated mouse retinae were exposed to GSM-900, GSM-1800, and universal mobile telecommunication system (UMTS) RF-EMF applying specific absorption rates (SAR) of 0 (sham), 0.02, 0.2, 2, and 20 W/kg. Temperature was kept constant within ±0.5 to 1 °C for GSM-900 and ±0.5 °C for GSM-1800 and UMTS. Responses of retinal ganglion cells to light stimuli of three intensities (0.5, 16, and 445 lx) were recorded before, during, and up to 35 min after exposure. Experiments were performed under double-blind conditions. Changes in light responses during and after exposure were determined for each condition (RF-EMF; SAR value; light intensity) with respect to the responses before exposure, respectively. Changes were calculated using the Euclidian distance of the n-dimensional response vectors, respectively. Some changes already occurred during sham (0 W/kg) exposure, reflecting the intrinsic variability in retinal ganglion cell responses. Comparison of the distance values from sham exposure with those from actual exposure yielded no significant differences. In addition, linear regression analysis of the distance values versus SAR values yielded no consistent dependence of light response changes. From these results we conclude that RF-EMF exposure at three mobile phone frequencies (GSM-900, GSM-1800, UMTS) and SARs up to 20 W/kg has no acute effects on retinal ganglion cell responses under constant temperature conditions.

  8. Dopamine and Full-Field Illumination Activate D1 and D2–D5-Type Receptors in Adult Rat Retinal Ganglion Cells

    PubMed Central

    Ogata, Genki; Stradleigh, Tyler W.; Partida, Gloria J.; Ishida, Andrew T.

    2012-01-01

    Dopamine can regulate signal generation and transmission by activating multiple receptors and signaling cascades, especially in striatum, hippocampus, and cerebral cortex. Dopamine modulates an even larger variety of cellular properties in retina, yet has been reported to do so by only D1 receptor-driven cyclic adenosine monophosphate (cAMP) increases or D2 receptor-driven cAMP decreases. Here, we test the possibility that dopamine operates differently on retinal ganglion cells, because the ganglion cell layer binds D1 and D2 receptor ligands, and displays changes in signaling components other than cAMP under illumination that should release dopamine. In adult rat retinal ganglion cells, based on patch-clamp recordings, Ca2+ imaging, and immunohistochemistry, we find that 1) spike firing is inhibited by dopamine and SKF 83959 (an agonist that does not activate homomeric D1 receptors or alter cAMP levels in other systems); 2) D1 and D2 receptor antagonists (SCH 23390, eticlopride, raclopride) counteract these effects; 3) these antagonists also block light-induced rises in cAMP, light-induced activation of Ca2+/calmodulin-dependent protein kinase II, and dopamine-induced Ca2+ influx; and 4) the Ca2+ rise is markedly reduced by removing extracellular Ca2+ and by an IP3 receptor antagonist (2-APB). These results provide the first evidence that dopamine activates a receptor in adult mammalian retinal neurons that is distinct from classical D1 and D2 receptors, and that dopamine can activate mechanisms in addition to cAMP and cAMP-dependent protein kinase to modulate retinal ganglion cell excitability. PMID:22678972

  9. Temporal properties of network-mediated responses to repetitive stimuli are dependent upon retinal ganglion cell type

    NASA Astrophysics Data System (ADS)

    Im, Maesoon; Fried, Shelley I.

    2016-04-01

    Objective. To provide artificially-elicited vision that is temporally dynamic, retinal prosthetic devices will need to repeatedly stimulate retinal neurons. However, given the diversity of physiological types of retinal ganglion cells (RGCs) as well as the heterogeneity of their responses to electric stimulation, temporal properties of RGC responses have not been adequately investigated. Here, we explored the cell type dependence of network-mediated RGC responses to repetitive electric stimulation at various stimulation rates. Approach. We examined responses of ON and OFF types of RGCs in the rabbit retinal explant to five consecutive stimuli with varying inter-stimulus intervals (10-1000 ms). Each stimulus was a 4 ms long monophasic sinusoidal cathodal current, which was applied epiretinally via a conical electrode. Spiking activity of targeted RGCs was recorded using a cell-attached patch electrode. Main results. ON and OFF cells had distinct responses to repetitive stimuli. Consistent with earlier studies, OFF cells always generated reduced responses to subsequent stimuli compared to responses to the first stimulus. In contrast, a new stimulus to ON cells suppressed all pending/ongoing responses from previous stimuli and initiated its own response that was remarkably similar to the response from a single stimulus in isolation. This previously unreported ‘reset’ behavior was observed exclusively and consistently in ON cells. These contrasts between ON and OFF cells created a range of stimulation rates (4-7 Hz) that maximized the ratio of the responses arising in ON versus OFF cells. Significance. Previous clinical testing reported that subjects perceive bright phosphenes (ON responses) and also prefer stimulation rates of 5-7 Hz. Our results suggest that responses of ON cells are weak at high rates of stimulation (> ˜7 Hz) due to the reset while responses of OFF cells are strong at low rates (< ˜4 Hz) due to reduced desensitization, both reducing the ratio

  10. Protection by an oral disubstituted hydroxylamine derivative against loss of retinal ganglion cell differentiation following optic nerve crush.

    PubMed

    Lindsey, James D; Duong-Polk, Karen X; Dai, Yi; Nguyen, Duy H; Leung, Christopher K; Weinreb, Robert N

    2013-01-01

    Thy-1 is a cell surface protein that is expressed during the differentiation of retinal ganglion cells (RGCs). Optic nerve injury induces progressive loss in the number of RGCs expressing Thy-1. The rate of this loss is fastest during the first week after optic nerve injury and slower in subsequent weeks. This study was undertaken to determine whether oral treatment with a water-soluble N-hydroxy-2,2,6,6-tetramethylpiperidine derivative (OT-440) protects against loss of Thy-1 promoter activation following optic nerve crush and whether this effect targets the earlier quick phase or the later slow phase. The retina of mice expressing cyan fluorescent protein under control of the Thy-1 promoter (Thy1-CFP mice) was imaged using a blue-light confocal scanning laser ophthalmoscope (bCSLO). These mice then received oral OT-440 prepared in cream cheese or dissolved in water, or plain vehicle, for two weeks and were imaged again prior to unilateral optic nerve crush. Treatments and weekly imaging continued for four more weeks. Fluorescent neurons were counted in the same defined retinal areas imaged at each time point in a masked fashion. When the counts at each time point were directly compared, the numbers of fluorescent cells at each time point were greater in the animals that received OT-440 in cream cheese by 8%, 27%, 52% and 60% than in corresponding control animals at 1, 2, 3 and 4 weeks after optic nerve crush. Similar results were obtained when the vehicle was water. Rate analysis indicated the protective effect of OT-440 was greatest during the first two weeks and was maintained in the second two weeks after crush for both the cream cheese vehicle study and water vehicle study. Because most of the fluorescent cells detected by bCSLO are RGCs, these findings suggest that oral OT-440 can either protect against or delay early degenerative responses occurring in RGCs following optic nerve injury.

  11. Mutant WDR36 directly affects axon growth of retinal ganglion cells leading to progressive retinal degeneration in mice

    PubMed Central

    Chi, Zai-Long; Yasumoto, Fumie; Sergeev, Yuri; Minami, Masayoshi; Obazawa, Minoru; Kimura, Itaru; Takada, Yuichiro; Iwata, Takeshi

    2010-01-01

    Primary open-angle glaucoma (POAG) is one of the three principal subtypes of glaucoma and among the leading cause of blindness worldwide. POAG is defined by cell death of the retinal ganglion cells (RGCs) and surrounding neuronal cells at higher or normal intraocular pressure (IOP). Coded by one of the three genes responsible for POAG, WD repeat-containing protein 36 (WDR36) has two domains with a similar folding. To address whether WDR36 is functionally important in the retina, we developed four transgenic mice strains overexpressing a wild-type (Wt) and three mutant variants of D606G, deletion of amino acids at positions 605–607 (Del605–607) and at 601–640 (Del601–640) equivalent to the location of the D658G mutation observed in POAG patients. A triple amino acid deletion of mouse Wdr36 at positions 605–607 corresponding to the deletion at positions 657–659 in humans developed progressive retinal degeneration at the peripheral retina with normal IOP. RGCs and connecting amacrine cell synapses were affected at the peripheral retina. Axon outgrowth rate of cultured RGC directly isolated from transgenic animal was significantly reduced by the Wdr36 mutation compared with Wt. Molecular modeling of wild and mutant mouse Wdr36 revealed that deletion at positions 605–607 removed three residues and a hydrogen bond, required to stabilize anti-parallel β-sheet of the 6th β-propeller in the second domain. We concluded that WDR36 plays an important functional role in the retina homeostasis and mutation to this gene can cause devastating retinal damage. These data will improve understanding of the functional property of WDR36 in the retina and provide a new animal model for glaucoma therapeutics. PMID:20631153

  12. Glia-Neuron Interactions in the Retina Can Be Studied in Cocultures of Müller Cells and Retinal Ganglion Cells

    PubMed Central

    Skytt, D. M.; Toft-Kehler, A. K.; Brændstrup, C. T.; Cejvanovic, S.; Gurubaran, I. S.; Bergersen, L. H.; Kolko, M.

    2016-01-01

    Glia-neuron partnership is important for inner retinal homeostasis and any disturbances may result in retinal ganglion cell (RGC) death. Müller cells support RGCs with essential functions such as removing excess glutamate and providing energy sources. The aim was to explore the impact of Müller cells on RGC survival. To investigate the Müller cell/RGC interactions we developed a coculture model, in which primary Müller cells were grown in inserts on top of pure primary RGC cultures. The impact of starvation and mitochondrial inhibition on the Müller cell ability to protect RGCs was studied. Moreover, the ability of Müller cells to remove glutamate from the extracellular space was investigated. RGC survival was evaluated by cell viability assays and glutamate uptake was assessed by kinetic uptake assays. We demonstrated a significantly increased RGC survival in presence of untreated and prestarved Müller cells. Additionally, prestarved Müller cells significantly increased RGC survival after mitochondrial inhibition. Finally, we revealed a significantly increased ability to take up glutamate in starved Müller cells. Overall, our study confirms essential roles of Müller cells in RGC survival. We suggest that targeting Müller cell function could have potential for future treatment strategies to prevent blinding neurodegenerative retinal diseases. PMID:27429974

  13. Glia-Neuron Interactions in the Retina Can Be Studied in Cocultures of Müller Cells and Retinal Ganglion Cells.

    PubMed

    Skytt, D M; Toft-Kehler, A K; Brændstrup, C T; Cejvanovic, S; Gurubaran, I S; Bergersen, L H; Kolko, M

    2016-01-01

    Glia-neuron partnership is important for inner retinal homeostasis and any disturbances may result in retinal ganglion cell (RGC) death. Müller cells support RGCs with essential functions such as removing excess glutamate and providing energy sources. The aim was to explore the impact of Müller cells on RGC survival. To investigate the Müller cell/RGC interactions we developed a coculture model, in which primary Müller cells were grown in inserts on top of pure primary RGC cultures. The impact of starvation and mitochondrial inhibition on the Müller cell ability to protect RGCs was studied. Moreover, the ability of Müller cells to remove glutamate from the extracellular space was investigated. RGC survival was evaluated by cell viability assays and glutamate uptake was assessed by kinetic uptake assays. We demonstrated a significantly increased RGC survival in presence of untreated and prestarved Müller cells. Additionally, prestarved Müller cells significantly increased RGC survival after mitochondrial inhibition. Finally, we revealed a significantly increased ability to take up glutamate in starved Müller cells. Overall, our study confirms essential roles of Müller cells in RGC survival. We suggest that targeting Müller cell function could have potential for future treatment strategies to prevent blinding neurodegenerative retinal diseases. PMID:27429974

  14. Coding Properties of Mouse Retinal Ganglion Cells with Dual-Peak Patterns with Respect to Stimulus Intervals

    PubMed Central

    Yan, Ru-Jia; Gong, Hai-Qing; Zhang, Pu-Ming; Liang, Pei-Ji

    2016-01-01

    How visual information is encoded in spikes of retinal ganglion cells (RGCs) is essential in visual neuroscience. In the present study, we investigated the coding properties of mouse RGCs with dual-peak patterns with respect to visual stimulus intervals. We first analyzed the response properties, and observed that the latencies and spike counts of the two response peaks in the dual-peak pattern exhibited systematic changes with the preceding light-OFF interval. We then applied linear discriminant analysis (LDA) to assess the relative contributions of response characteristics of both peaks in information coding regarding the preceding stimulus interval. It was found that for each peak, the discrimination results were far better than chance level based on either latency or spike count, and were further improved by using the combination of the two parameters. Furthermore, the best discrimination results were obtained when latencies and spike counts of both peaks were considered in combination. In addition, the correct rate for stimulation discrimination was higher when RGC population activity was considered as compare to single neuron's activity, and the correct rate was increased with the group size. These results suggest that rate coding, temporal coding, and population coding are all involved in encoding the different stimulus-interval patterns, and the two response peaks in the dual-peak pattern carry complementary information about stimulus interval. PMID:27486396

  15. Semi-automated, Quantitative Analysis of Retinal Ganglion Cell Morphology in Mice Selectively Expressing Yellow Fluorescent Protein

    PubMed Central

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

    2012-01-01

    The development of transgenic mouse lines that selectively label a subset of neurons provides unique opportunities to study detailed neuronal morphology and morphological changes under experimental conditions. In the present study, a mouse line in which a small number of retinal ganglion cells (RGCs) express yellow fluorescent protein (YFP) under control of the Thy-1 promoter was used (Feng et al., 2000). We characterized the number, distribution by retinal region and eccentricity of YFP-labeled RGCs using fluorescence microscopy and StereoInvestigator software (MicroBrightField, VT, USA). Then, we captured images of 4–6 YFP-expressing RGCs from each of 8 retinal regions by confocal microscopy, producing 3-dimensional and flattened data sets. A new semi-automated method to quantify the soma size, dendritic length and dendritic arbor complexity was developed using MetaMorph software (Molecular Devices, PA, USA). Our results show that YFP is expressed in 0.2% of all RGCs. Expression of YFP was not significantly different in central versus peripheral retina, but there were higher number of YFP expressing RGCs in the temporal quadrant than in the nasal. By confocal-based analysis, 58% of RGCs expressing YFP did so at a high level, with the remainder distributed in decreasing levels of brightness. Variability in detailed morphometric parameters was as great between two fellow retinas as in retinas from different mice. The analytic methods developed for this selective YFP expressing RGC model permit quantitative comparisons of parameters relevant to neuronal injury. PMID:22210127

  16. Mitochondrial pathogenic mechanism and degradation in optineurin E50K mutation-mediated retinal ganglion cell degeneration

    PubMed Central

    Shim, Myoung Sup; Takihara, Yuji; Kim, Keun-Young; Iwata, Takeshi; Yue, Beatrice Y. J. T.; Inatani, Masaru; Weinreb, Robert N.; Perkins, Guy A.; Ju, Won-Kyu

    2016-01-01

    Mutations in optineurin (OPTN) are linked to the pathology of primary open angle glaucoma (POAG) and amyotrophic lateral sclerosis. Emerging evidence indicates that OPTN mutation is involved in accumulation of damaged mitochondria and defective mitophagy. Nevertheless, the role played by an OPTN E50K mutation in the pathogenic mitochondrial mechanism that underlies retinal ganglion cell (RGC) degeneration in POAG remains unknown. We show here that E50K expression induces mitochondrial fission-mediated mitochondrial degradation and mitophagy in the axons of the glial lamina of aged E50K−tg mice in vivo. While E50K activates the Bax pathway and oxidative stress, and triggers dynamics alteration-mediated mitochondrial degradation and mitophagy in RGC somas in vitro, it does not affect transport dynamics and fission of mitochondria in RGC axons in vitro. These results strongly suggest that E50K is associated with mitochondrial dysfunction in RGC degeneration in synergy with environmental factors such as aging and/or oxidative stress. PMID:27654856

  17. 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.

  18. 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.

  19. Viral vector-mediated downregulation of RhoA increases survival and axonal regeneration of retinal ganglion cells

    PubMed Central

    Koch, Jan Christoph; Tönges, Lars; Michel, Uwe; Bähr, Mathias; Lingor, Paul

    2014-01-01

    The Rho/ROCK pathway is a promising therapeutic target in neurodegenerative and neurotraumatic diseases. Pharmacological inhibition of various pathway members has been shown to promote neuronal regeneration and survival. However, because pharmacological inhibitors are inherently limited in their specificity, shRNA-mediated approaches can add more information on the function of each single kinase involved. Thus, we generated adeno-associated viral vectors (AAV) to specifically downregulate Ras homologous member A (RhoA) via shRNA. We found that specific knockdown of RhoA promoted neurite outgrowth of retinal ganglion cells (RGC) grown on the inhibitory substrate chondroitin sulfate proteoglycan (CSPG) as well as neurite regeneration of primary midbrain neurons (PMN) after scratch lesion. In the rat optic nerve crush (ONC) model in vivo, downregulation of RhoA significantly enhanced axonal regeneration compared to control. Moreover, survival of RGC transduced with AAV expressing RhoA-shRNA was substantially increased at 2 weeks after optic nerve axotomy. Compared to previous data using pharmacological inhibitors to target RhoA, its upstream regulator Nogo or its main downstream target ROCK, the specific effects of RhoA downregulation shown here were most pronounced in regard to promoting RGC survival but neurite outgrowth and axonal regeneration were also increased significantly. Taken together, we show here that specific knockdown of RhoA substantially increases neuronal survival after optic nerve axotomy and modestly increases neurite outgrowth in vitro and axonal regeneration after optic nerve crush. PMID:25249936

  20. Age-related hearing loss: prevention of threshold declines, cell loss and apoptosis in spiral ganglion neurons

    PubMed Central

    Zhu, Xiaoxia; Walton, Joseph P.

    2016-01-01

    Age-related hearing loss (ARHL) -presbycusis - is the most prevalent neurodegenerative disease and number one communication disorder of our aged population; and affects hundreds of millions of people worldwide. Its prevalence is close to that of cardiovascular disease and arthritis, and can be a precursor to dementia. The auditory perceptual dysfunction is well understood, but knowledge of the biological bases of ARHL is still somewhat lacking. Surprisingly, there are no FDA-approved drugs for treatment. Based on our previous studies of human subjects, where we discovered relations between serum aldosterone levels and the severity of ARHL, we treated middle age mice with aldosterone, which normally declines with age in all mammals. We found that hearing thresholds and suprathreshold responses significantly improved in the aldosterone-treated mice compared to the non-treatment group. In terms of cellular and molecular mechanisms underlying this therapeutic effect, additional experiments revealed that spiral ganglion cell survival was significantly improved, mineralocorticoid receptors were upregulated via post-translational protein modifications, and age-related intrinsic and extrinsic apoptotic pathways were blocked by the aldosterone therapy. Taken together, these novel findings pave the way for translational drug development towards the first medication to prevent the progression of ARHL. PMID:27667674

  1. A new intraretinal recording system with multiple-barreled electrodes for pharmacological studies on cat retinal ganglion cells.

    PubMed

    Takao, M; Wang1, Y; Miyoshi, T; Fujita, I; Fukuda, Y

    2000-04-01

    To overcome technical difficulties associated with in vivo intraretinal recordings of cat retinal ganglion cells (RGCs) with multiple-barreled electrodes, we developed a new guide-trocar system that consisted of a small-diameter and large-diameter pipes. We also improved the method to construct tungsten-in-glass multiple-barreled electrodes suitable for intraretinal recording from RGCs. Only the small-diameter pipe was inserted into the eye ball through the sclera, through which only the taper part of a multiple-barreled electrode pass. The large-diameter pipe stably held the electrode at its trunk and remained outside the eye ball. Insertion of only the small-diameter pipe minimized damages in the eye ball and prevented the eye ball movements while positioning the electrode. The system allowed us to keep the recordings stable for more than 1 h. Iontophoretically applied L-glutamate successfully activated RGCs of both X and Y types in the cat retina. PMID:10771079

  2. Volume regulation in response to hypo-osmotic stress in goldfish retinal ganglion cell axons regenerating in vitro.

    PubMed

    Edmonds, B T; Koenig, E

    1990-06-18

    Goldfish retinal ganglion cell (RGC) axons regenerating in vitro were used to investigate the volume regulatory response to hypo-osmotic stress. Reducing the tonicity of the bathing medium to half strength caused an immediate swelling of axons; however, within 1 min a progressive volume reduction ensued which stabilized at near control volume over a period of 10 min. This regulatory volume decrease (RVD) was attenuated by elevated [K+]o, Ca2(+)-activated K+ channel antagonists, and calmidazolium, a potent calmodulin inhibitor. Inclusion of ATP-gamma S in the hypotonic bathing medium led to a loading of stressed axons which resulted in an excessive volume reduction that reflected an overshooting of the RVD response. The latter suggested the importance of phosphorylation/dephosphorylation reactions in the RVD response pathway. Cytochalasin D and colchicine had no effect on the development of the typical RVD response, providing no evidence of involvement of actin or microtubule cytoskeletons in the volume reduction mechanism of the immature axons. The results are consistent with the hypothesis that hypo-osmotic stress activates a calcium/calmodulin dependent membrane pathway, which probably involves transient phosphorylation, leading to a loss of cellular K+ and osmotically obligated water which restorates normal axonal volume.

  3. Neuropilin-2/Semaphorin-3F-mediated repulsion promotes inner hair cell innervation by spiral ganglion neurons

    PubMed Central

    Coate, Thomas M; Spita, Nathalie A; Zhang, Kaidi D; Isgrig, Kevin T; Kelley, Matthew W

    2015-01-01

    Auditory function is dependent on the formation of specific innervation patterns between mechanosensory hair cells (HCs) and afferent spiral ganglion neurons (SGNs). In particular, type I SGNs must precisely connect with inner HCs (IHCs) while avoiding connections with nearby outer HCs (OHCs). The factors that mediate these patterning events are largely unknown. Using sparse-labeling and time-lapse imaging, we visualized for the first time the behaviors of developing SGNs including active retraction of processes from OHCs, suggesting that some type I SGNs contact OHCs before forming synapses with IHCs. In addition, we demonstrate that expression of Semaphorin-3F in the OHC region inhibits type I SGN process extension by activating Neuropilin-2 receptors expressed on SGNs. These results suggest a model in which cochlear innervation patterns by type I SGNs are determined, at least in part, through a Semaphorin-3F-mediated inhibitory signal that impedes processes from extending beyond the IHC region. DOI: http://dx.doi.org/10.7554/eLife.07830.001 PMID:26302206

  4. Controlling cell-cell interactions using surface acoustic waves.

    PubMed

    Guo, Feng; Li, Peng; French, Jarrod B; Mao, Zhangming; Zhao, Hong; Li, Sixing; Nama, Nitesh; Fick, James R; Benkovic, Stephen J; Huang, Tony Jun

    2015-01-01

    The interactions between pairs of cells and within multicellular assemblies are critical to many biological processes such as intercellular communication, tissue and organ formation, immunological reactions, and cancer metastasis. The ability to precisely control the position of cells relative to one another and within larger cellular assemblies will enable the investigation and characterization of phenomena not currently accessible by conventional in vitro methods. We present a versatile surface acoustic wave technique that is capable of controlling the intercellular distance and spatial arrangement of cells with micrometer level resolution. This technique is, to our knowledge, among the first of its kind to marry high precision and high throughput into a single extremely versatile and wholly biocompatible technology. We demonstrated the capabilities of the system to precisely control intercellular distance, assemble cells with defined geometries, maintain cellular assemblies in suspension, and translate these suspended assemblies to adherent states, all in a contactless, biocompatible manner. As an example of the power of this system, this technology was used to quantitatively investigate the gap junctional intercellular communication in several homotypic and heterotypic populations by visualizing the transfer of fluorescent dye between cells.

  5. Horizontal cell feedback without cone type-selective inhibition mediates "red-green" color opponency in midget ganglion cells of the primate retina.

    PubMed

    Crook, Joanna D; Manookin, Michael B; Packer, Orin S; Dacey, Dennis M

    2011-02-01

    The distinctive red-green dimension of human and nonhuman primate color perception arose relatively recently in the primate lineage with the appearance of separate long (L) and middle (M) wavelength-sensitive cone photoreceptor types. "Midget" ganglion cells of the retina use center-surround receptive field structure to combine L and M cone signals antagonistically and thereby establish a "red-green, color-opponent" visual pathway. However, the synaptic origin of red-green opponency is unknown, and conflicting evidence for either random or L versus M cone-selective inhibitory circuits has divergent implications for the developmental and evolutionary origins of trichromatic color vision. Here we directly measure the synaptic conductances evoked by selective L or M cone stimulation in the midget ganglion cell dendritic tree and show that L versus M cone opponency arises presynaptic to the midget cell and is transmitted entirely by modulation of an excitatory conductance. L and M cone synaptic inhibition is feedforward and thus occurs in phase with excitation for both cone types. Block of GABAergic and glycinergic receptors does not attenuate or modify L versus M cone antagonism, discounting both presynaptic and postsynaptic inhibition as sources of cone opponency. In sharp contrast, enrichment of retinal pH-buffering capacity, to attenuate negative feedback from horizontal cells that sum L and M cone inputs linearly and without selectivity, completely abolished both the midget cell surround and all chromatic opponency. Thus, red-green opponency appears to arise via outer retinal horizontal cell feedback that is not cone type selective without recourse to any inner retinal L versus M cone inhibitory pathways. PMID:21289186

  6. The effects of acoustic vibration on fibroblast cell migration.

    PubMed

    Mohammed, Taybia; Murphy, Mark F; Lilley, Francis; Burton, David R; Bezombes, Frederic

    2016-12-01

    Cells are known to interact and respond to external mechanical cues and recent work has shown that application of mechanical stimulation, delivered via acoustic vibration, can be used to control complex cell behaviours. Fibroblast cells are known to respond to physical cues generated in the extracellular matrix and it is thought that such cues are important regulators of the wound healing process. Many conditions are associated with poor wound healing, so there is need for treatments/interventions, which can help accelerate the wound healing process. The primary aim of this research was to investigate the effects of mechanical stimulation upon the migratory and morphological properties of two different fibroblast cells namely; human lung fibroblast cells (LL24) and subcutaneous areolar/adipose mouse fibroblast cells (L929). Using a speaker-based system, the effects of mechanical stimulation (0-1600Hz for 5min) on the mean cell migration distance (μm) and actin organisation was investigated. The results show that 100Hz acoustic vibration enhanced cell migration for both cell lines whereas acoustic vibration above 100Hz was found to decrease cell migration in a frequency dependent manner. Mechanical stimulation was also found to promote changes to the morphology of both cell lines, particularly the formation of lamellipodia and filopodia. Overall lamellipodia was the most prominent actin structure displayed by the lung cell (LL24), whereas filopodia was the most prominent actin feature displayed by the fibroblast derived from subcutaneous areolar/adipose tissue. Mechanical stimulation at all the frequencies used here was found not to affect cell viability. These results suggest that low-frequency acoustic vibration may be used as a tool to manipulate the mechanosensitivity of cells to promote cell migration. PMID:27612824

  7. Shh/Boc Signaling Is Required for Sustained Generation of Ipsilateral Projecting Ganglion Cells in the Mouse Retina

    PubMed Central

    Sánchez-Camacho, Cristina; Carreres, M. Isabel; Herrera, Eloisa; Okada, Ami; Bovolenta, Paola

    2013-01-01

    Sonic Hedgehog (Shh) signaling is an important determinant of vertebrate retinal ganglion cell (RGC) development. In mice, there are two major RGC populations: (1) the Islet2-expressing contralateral projecting (c)RGCs, which both produce and respond to Shh; and (2) the Zic2-expressing ipsilateral projecting RGCs (iRGCs), which lack Shh expression. In contrast to cRGCs, iRGCs, which are generated in the ventrotemporal crescent (VTC) of the retina, specifically express Boc, a cell adhesion molecule that acts as a high-affinity receptor for Shh. In Boc−/− mutant mice, the ipsilateral projection is significantly decreased. Here, we demonstrate that this phenotype results, at least in part, from the misspecification of a proportion of iRGCs. In Boc−/− VTC, the number of Zic2-positive RGCs is reduced, whereas more Islet2/Shh-positive RGCs are observed, a phenotype also detected in Zic2 and Foxd1 null embryos. Consistent with this observation, organization of retinal projections at the dorsallateral geniculate nucleus is altered in Boc−/− mice. Analyses of the molecular and cellular consequences of introducing Shh into the developing VTC and Zic2 and Boc into the central retina indicate that Boc expression alone is in sufficient to fully activate the ipsilateral program and that Zic2 regulates Shh expression. Taking these data together, we propose that expression of Boc in cells from the VTC is required to sustain Zic2 expression, likely by regulating the levels of Shh signaling from the nearby cRGCs. Zic2, in turn, directly or indirectly, counteracts Shh and Islet2 expression in the VTC and activates the ipsilateral program. PMID:23678105

  8. Type II spiral ganglion afferent neurons drive medial olivocochlear reflex suppression of the cochlear amplifier.

    PubMed

    Froud, Kristina E; Wong, Ann Chi Yan; Cederholm, Jennie M E; Klugmann, Matthias; Sandow, Shaun L; Julien, Jean-Pierre; Ryan, Allen F; Housley, Gary D

    2015-01-01

    The dynamic adjustment of hearing sensitivity and frequency selectivity is mediated by the medial olivocochlear efferent reflex, which suppresses the gain of the 'cochlear amplifier' in each ear. Such efferent feedback is important for promoting discrimination of sounds in background noise, sound localization and protecting the cochleae from acoustic overstimulation. However, the sensory driver for the olivocochlear reflex is unknown. Here, we resolve this longstanding question using a mouse model null for the gene encoding the type III intermediate filament peripherin (Prph). Prph((-/-)) mice lacked type II spiral ganglion neuron innervation of the outer hair cells, whereas innervation of the inner hair cells by type I spiral ganglion neurons was normal. Compared with Prph((+/+)) controls, both contralateral and ipsilateral olivocochlear efferent-mediated suppression of the cochlear amplifier were absent in Prph((-/-)) mice, demonstrating that outer hair cells and their type II afferents constitute the sensory drive for the olivocochlear efferent reflex.

  9. Evaluation of solar cell welds by scanning acoustic microscopy

    NASA Technical Reports Server (NTRS)

    Klima, S. J.; Frey, W. E.; Baraona, C. R.

    1982-01-01

    Scanning laser acoustic microscopy was used to nondestructively evaluate solar cell interconnect bonds made by resistance welding. Both copper-silver and silver-silver welds were analyzed. The bonds were produced either by a conventional parallel-gap welding technique using rectangular electrodes or new annular gap design with a circular electrode cross section. With the scanning laser acoustic microscope, it was possible to produce a real time television image which reveales the weld configuration as it relates to electrode geometry. The effect of electrode misalinement with the surface of the cell was also determined. A preliminary metallographic analysis was performed on selected welds to establish the relationship between actual size and shape of the weld area and the information available from acoustic micrographs.

  10. Cell Deformation by Single-beam Acoustic Trapping: A Promising Tool for Measurements of Cell Mechanics

    PubMed Central

    Hwang, Jae Youn; Kim, Jihun; Park, Jin Man; Lee, Changyang; Jung, Hayong; Lee, Jungwoo; Shung, K. Kirk

    2016-01-01

    We demonstrate a noncontact single-beam acoustic trapping method for the quantification of the mechanical properties of a single suspended cell with label-free. Experimentally results show that the single-beam acoustic trapping force results in morphological deformation of a trapped cell. While a cancer cell was trapped in an acoustic beam focus, the morphological changes of the immobilized cell were monitored using bright-field imaging. The cell deformability was then compared with that of a trapped polystyrene microbead as a function of the applied acoustic pressure for a better understanding of the relationship between the pressure and degree of cell deformation. Cell deformation was found to become more pronounced as higher pressure levels were applied. Furthermore, to determine if this acoustic trapping method can be exploited in quantifying the cell mechanics in a suspension and in a non-contact manner, the deformability levels of breast cancer cells with different degrees of invasiveness due to acoustic trapping were compared. It was found that highly-invasive breast cancer cells exhibited greater deformability than weakly-invasive breast cancer cells. These results clearly demonstrate that the single-beam acoustic trapping technique is a promising tool for non-contact quantitative assessments of the mechanical properties of single cells in suspensions with label-free. PMID:27273365

  11. Cell Deformation by Single-beam Acoustic Trapping: A Promising Tool for Measurements of Cell Mechanics

    NASA Astrophysics Data System (ADS)

    Hwang, Jae Youn; Kim, Jihun; Park, Jin Man; Lee, Changyang; Jung, Hayong; Lee, Jungwoo; Shung, K. Kirk

    2016-06-01

    We demonstrate a noncontact single-beam acoustic trapping method for the quantification of the mechanical properties of a single suspended cell with label-free. Experimentally results show that the single-beam acoustic trapping force results in morphological deformation of a trapped cell. While a cancer cell was trapped in an acoustic beam focus, the morphological changes of the immobilized cell were monitored using bright-field imaging. The cell deformability was then compared with that of a trapped polystyrene microbead as a function of the applied acoustic pressure for a better understanding of the relationship between the pressure and degree of cell deformation. Cell deformation was found to become more pronounced as higher pressure levels were applied. Furthermore, to determine if this acoustic trapping method can be exploited in quantifying the cell mechanics in a suspension and in a non-contact manner, the deformability levels of breast cancer cells with different degrees of invasiveness due to acoustic trapping were compared. It was found that highly-invasive breast cancer cells exhibited greater deformability than weakly-invasive breast cancer cells. These results clearly demonstrate that the single-beam acoustic trapping technique is a promising tool for non-contact quantitative assessments of the mechanical properties of single cells in suspensions with label-free.

  12. Substituting mouse transcription factor Pou4f2 with a sea urchin orthologue restores retinal ganglion cell development.

    PubMed

    Mao, Chai-An; Agca, Cavit; Mocko-Strand, Julie A; Wang, Jing; Ullrich-Lüter, Esther; Pan, Ping; Wang, Steven W; Arnone, Maria Ina; Frishman, Laura J; Klein, William H

    2016-03-16

    Pou domain transcription factor Pou4f2 is essential for the development of retinal ganglion cells (RGCs) in the vertebrate retina. A distant orthologue of Pou4f2 exists in the genome of the sea urchin (class Echinoidea) Strongylocentrotus purpuratus (SpPou4f1/2), yet the photosensory structure of sea urchins is strikingly different from that of the mammalian retina. Sea urchins have no obvious eyes, but have photoreceptors clustered around their tube feet disc. The mechanisms that are associated with the development and function of photoreception in sea urchins are largely unexplored. As an initial approach to better understand the sea urchin photosensory structure and relate it to the mammalian retina, we asked whether SpPou4f1/2 could support RGC development in the absence of Pou4f2. To answer this question, we replaced genomic Pou4f2 with an SpPou4f1/2 cDNA. In Pou4f2-null mice, retinas expressing SpPou4f1/2 were outwardly identical to those of wild-type mice. SpPou4f1/2 retinas exhibited dark-adapted electroretinogram scotopic threshold responses, indicating functionally active RGCs. During retinal development, SpPou4f1/2 activated RGC-specific genes and in S. purpuratus, SpPou4f2 was expressed in photoreceptor cells of tube feet in a pattern distinct from Opsin4 and Pax6. Our results suggest that SpPou4f1/2 and Pou4f2 share conserved components of a gene network for photosensory development and they maintain their conserved intrinsic functions despite vast morphological differences in mouse and sea urchin photosensory structures. PMID:26962139

  13. Substituting mouse transcription factor Pou4f2 with a sea urchin orthologue restores retinal ganglion cell development.

    PubMed

    Mao, Chai-An; Agca, Cavit; Mocko-Strand, Julie A; Wang, Jing; Ullrich-Lüter, Esther; Pan, Ping; Wang, Steven W; Arnone, Maria Ina; Frishman, Laura J; Klein, William H

    2016-03-16

    Pou domain transcription factor Pou4f2 is essential for the development of retinal ganglion cells (RGCs) in the vertebrate retina. A distant orthologue of Pou4f2 exists in the genome of the sea urchin (class Echinoidea) Strongylocentrotus purpuratus (SpPou4f1/2), yet the photosensory structure of sea urchins is strikingly different from that of the mammalian retina. Sea urchins have no obvious eyes, but have photoreceptors clustered around their tube feet disc. The mechanisms that are associated with the development and function of photoreception in sea urchins are largely unexplored. As an initial approach to better understand the sea urchin photosensory structure and relate it to the mammalian retina, we asked whether SpPou4f1/2 could support RGC development in the absence of Pou4f2. To answer this question, we replaced genomic Pou4f2 with an SpPou4f1/2 cDNA. In Pou4f2-null mice, retinas expressing SpPou4f1/2 were outwardly identical to those of wild-type mice. SpPou4f1/2 retinas exhibited dark-adapted electroretinogram scotopic threshold responses, indicating functionally active RGCs. During retinal development, SpPou4f1/2 activated RGC-specific genes and in S. purpuratus, SpPou4f2 was expressed in photoreceptor cells of tube feet in a pattern distinct from Opsin4 and Pax6. Our results suggest that SpPou4f1/2 and Pou4f2 share conserved components of a gene network for photosensory development and they maintain their conserved intrinsic functions despite vast morphological differences in mouse and sea urchin photosensory structures.

  14. 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.

  15. GlyRα2, not GlyRα3, modulates the receptive field surround of OFF retinal ganglion cells.

    PubMed

    Zhang, Chi; Nobles, Regina D; McCall, Maureen A

    2015-01-01

    Receptive fields (RFs) of most retinal ganglion cells (RGCs) consist of an excitatory center and suppressive surround. The RF center arises from the summation of excitatory bipolar cell glutamatergic inputs, whereas the surround arises from lateral inhibitory inputs. In the retina, both gamma amino butyric acid (GABA) and glycine are inhibitory neurotransmitters. A clear role for GABAergic inhibition modulating the RGC RF surround has been demonstrated across species. Glycinergic inhibition is more commonly associated with RF center modulation, although there is some evidence that it may contribute to the RF surround. The synaptic glycinergic chloride channels are formed by three homomeric β and two homomeric α subunits that can be glycine receptor (GlyR) α1, α2, α3, or α4. GlyRα composition is responsible for currents with distinct decay kinetics. Their expression within the inner plexiform laminae and neuronal subtypes also differ. We studied the role of GlyR subunit selective modulation of RGC RF surrounds, using mice lacking GlyRα2 (Glra2 -/-), GlyRα3 (Glra3 -/-), or both (Glra2/3 -/-). We chose this molecular genetic approach instead of pharmacological manipulation because there are no subunit selective antagonists and strychnine blocks all GlyRs. Comparisons of annulus-evoked responses among wild type (WT) and GlyRα knockouts (Glra2 -/-, Glra3 -/- and Glra2/3 -/-) show that GlyRα2 inhibition enhances RF surround suppression and post-stimulus excitation in only WT OFF RGCs. Similarities in the responses in Glra2 -/- and Glra2/3 -/- RGCs verify these conclusions. Based on previous and current data, we propose that GlyRα2-mediated input uses a crossover inhibitory circuit. Further, we suggest that GlyRα2 modulates the OFF RGC RF center and surround independently. In summary, our results define a selective GlyR subunit-specific control of RF surround suppression in OFF RGCs. PMID:26923349

  16. Neuropeptide FF receptor modulates potassium currents in a dorsal root ganglion cell line.

    PubMed

    Mollereau, Catherine; Roumy, Michel; Zajac, Jean-Marie

    2011-01-01

    This study investigated the presence of neuropeptide FF (NPFF) receptors on F-11 cells, a hybridoma derived from rat dorsal root ganglia (DRG) and mouse neuroblastoma. Binding experiments revealed a low density (4 fmol/mg) of high affinity (0.5 nM) [(3)H]-EYF binding sites in these cells. The whole-cell planar patch-clamp technique showed that dNPA, a selective NPFF(2) agonist, increased the voltage-dependent potassium outward currents (about 30 pA/pF) by 21%; this reversible effect on sustained delayed potassium currents is blocked by tetraethylammonium. The similar effects of NPFF and opioid agonists on K(+) currents in this cell line may explain their similar antinociceptive actions at the spinal level.

  17. The Ionic Permeability Changes during Acetylcholine-Induced Responses of Aplysia Ganglion Cells

    PubMed Central

    Sato, Makoto; Austin, George; Yai, Hideko; Maruhashi, Juro

    1968-01-01

    ACh-induced depolarization (D response) in D cells markedly decreases as the external Na+ is reduced. However, when Na+ is completely replaced with Mg++, the D response remains unchanged. When Na+ is replaced with Tris(hydroxymethyl)aminomethane, the D response completely disappears, except for a slight decrease in membrane resistance. ACh-induced hyperpolarization (H response) in H cells is markedly depressed as the external Cl- is reduced. Frequently, the reversal of the H response; i.e., depolarization, is observed during perfusion with Cl--free media. In cells which show both D and H responses superimposed, it was possible to separate these responses from each other by perfusing the cells with either Na+-free or Cl--free Ringer's solution. High [K+]0 often caused a marked hyperpolarization in either D or H cells. This is due to the primary effect of high [K+]0 on the presynaptic inhibitory fibers. The removal of this inhibitory afferent interference by applying Nembutal readily disclosed the predicted K+ depolarization. In perfusates containing normal [Na+]0, the effects of Ca++ and Mg++ on the activities of postsynaptic membrane were minimal, supporting the current theory that the effects of these ions on the synaptic transmission are mainly presynaptic. The possible mechanism of the hyperpolarization produced by simultaneous perfusion with both high [K+]0 and ACh in certain H cells is explained quantitatively under the assumption that ACh induces exclusively an increase in Cl- permeability of the H membrane. PMID:5648831

  18. Prolonged delivery of brain-derived neurotrophic factor by adenovirus-infected Müller cells temporarily rescues injured retinal ganglion cells

    PubMed Central

    Di Polo, Adriana; Aigner, Ludwig J.; Dunn, Robert J.; Bray, Garth M.; Aguayo, Albert J.

    1998-01-01

    In this study, we demonstrate that: (i) injection of an adenovirus (Ad) vector containing the brain-derived neurotrophic factor (BDNF) gene (Ad.BDNF) into the vitreous chamber of adult rats results in selective transgene expression by Müller cells; (ii) in vitro, Müller cells infected with Ad.BDNF secrete BDNF that enhances neuronal survival; (iii) in vivo, Ad-mediated expression of functional BDNF by Müller cells, temporarily extends the survival of axotomized retinal ganglion cells (RGCs); 16 days after axotomy, injured retinas treated with Ad.BDNF showed a 4.5-fold increase in surviving RGCs compared with control retinas; (iv) the transient expression of the BDNF transgene, which lasted ≈10 days, can be prolonged with immunosuppression for at least 30 days, and such Ad-mediated BDNF remains biologically active, (v) persistent expression of BDNF by infected Müller cells does not further enhance the survival of injured RGCs, indicating that the effect of this neurotrophin on RGC survival is limited by changes induced by the lesion within 10–16 days after optic nerve transection rather than the availability of BDNF. Thus, Ad-transduced Müller cells are a novel pathway for sustained delivery of BDNF to acutely-injured RGCs. Because these cells span the entire thickness of the retina, Ad-mediated gene delivery to Müller cells may also be useful to influence photoreceptors and other retinal neurons. PMID:9520478

  19. Cell separation using tilted-angle standing surface acoustic waves.

    PubMed

    Ding, Xiaoyun; Peng, Zhangli; Lin, Sz-Chin Steven; Geri, Michela; Li, Sixing; Li, Peng; Chen, Yuchao; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2014-09-01

    Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and efficiency of currently available acoustic-based approaches, however, are limited, thereby restricting their widespread application in research and health diagnostics. In this work, we introduce a unique configuration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optimally designed inclination to the flow direction in the microfluidic channel. We demonstrate that this design significantly improves the efficiency and sensitivity of acoustic separation techniques. To optimize our device design, we carried out systematic simulations of cell trajectories, matching closely with experimental results. Using numerically optimized design of taSSAW, we successfully separated 2- and 10-µm-diameter polystyrene beads with a separation efficiency of ∼ 99%, and separated 7.3- and 9.9-µm-polystyrene beads with an efficiency of ∼ 97%. We illustrate that taSSAW is capable of effectively separating particles-cells of approximately the same size and density but different compressibility. Finally, we demonstrate the effectiveness of the present technique for biological-biomedical applications by sorting MCF-7 human breast cancer cells from nonmalignant leukocytes, while preserving the integrity of the separated cells. The method introduced here thus offers a unique route for separating circulating tumor cells, and for label-free cell separation with potential applications in biological research, disease diagnostics, and clinical practice.

  20. Cell separation using tilted-angle standing surface acoustic waves

    PubMed Central

    Ding, Xiaoyun; Peng, Zhangli; Lin, Sz-Chin Steven; Geri, Michela; Li, Sixing; Li, Peng; Chen, Yuchao; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2014-01-01

    Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and efficiency of currently available acoustic-based approaches, however, are limited, thereby restricting their widespread application in research and health diagnostics. In this work, we introduce a unique configuration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optimally designed inclination to the flow direction in the microfluidic channel. We demonstrate that this design significantly improves the efficiency and sensitivity of acoustic separation techniques. To optimize our device design, we carried out systematic simulations of cell trajectories, matching closely with experimental results. Using numerically optimized design of taSSAW, we successfully separated 2- and 10-µm-diameter polystyrene beads with a separation efficiency of ∼99%, and separated 7.3- and 9.9-µm-polystyrene beads with an efficiency of ∼97%. We illustrate that taSSAW is capable of effectively separating particles–cells of approximately the same size and density but different compressibility. Finally, we demonstrate the effectiveness of the present technique for biological–biomedical applications by sorting MCF-7 human breast cancer cells from nonmalignant leukocytes, while preserving the integrity of the separated cells. The method introduced here thus offers a unique route for separating circulating tumor cells, and for label-free cell separation with potential applications in biological research, disease diagnostics, and clinical practice. PMID:25157150

  1. Cell separation using tilted-angle standing surface acoustic waves.

    PubMed

    Ding, Xiaoyun; Peng, Zhangli; Lin, Sz-Chin Steven; Geri, Michela; Li, Sixing; Li, Peng; Chen, Yuchao; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2014-09-01

    Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and efficiency of currently available acoustic-based approaches, however, are limited, thereby restricting their widespread application in research and health diagnostics. In this work, we introduce a unique configuration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optimally designed inclination to the flow direction in the microfluidic channel. We demonstrate that this design significantly improves the efficiency and sensitivity of acoustic separation techniques. To optimize our device design, we carried out systematic simulations of cell trajectories, matching closely with experimental results. Using numerically optimized design of taSSAW, we successfully separated 2- and 10-µm-diameter polystyrene beads with a separation efficiency of ∼ 99%, and separated 7.3- and 9.9-µm-polystyrene beads with an efficiency of ∼ 97%. We illustrate that taSSAW is capable of effectively separating particles-cells of approximately the same size and density but different compressibility. Finally, we demonstrate the effectiveness of the present technique for biological-biomedical applications by sorting MCF-7 human breast cancer cells from nonmalignant leukocytes, while preserving the integrity of the separated cells. The method introduced here thus offers a unique route for separating circulating tumor cells, and for label-free cell separation with potential applications in biological research, disease diagnostics, and clinical practice. PMID:25157150

  2. Dynamic responses of Xenopus retinal ganglion cell axon growth cones to netrin-1 as they innervate their in vivo target

    PubMed Central

    Shirkey, Nicole J.; Manitt, Colleen; Zuniga, Liliana; Cohen-Cory, Susana

    2012-01-01

    Netrin-1 influences retinal ganglion cell (RGC) axon pathfinding and also participates in the branching and synaptic differentiation of mature RGC axons at their target. To investigate whether netrin also serves as an early target recognition signal in the brain, we examined the dynamic behavior of Xenopus RGC axons soon after they innervate the optic tectum. Time-lapse confocal microscopy imaging of RGC axons expressing EYFP demonstrated that netrin-1 is involved in early axon branching, as recombinant netrin-1 halted further advancement of growth cones into the tectum and induced back branching. RGC growth cones exhibited differential responses to netrin-1 that depended on the degree of differentiation of the axon and the developmental stage of the tadpole. Netrin-1 decreased the total number of branches on newly arrived RGC growth cones at the target, but increased the dynamic branching of more mature arbors at the later developmental stage. To further explore the response of axonal growth cones to netrin, Xenopus RGC axons were followed in culture by time-lapse imaging. Exposure to netrin-1 rapidly increased the forward advancement of the axon and decreased the size and expanse of the growth cone, while also inducing back branching. Taken together, the differential in vivo and in vitro responses to netrin-1 suggest that netrin alone is not sufficient to induce the cessation of growth cone advancement in the absence of a target, but can independently modulate axon branching. Collectively, our findings reveal a novel role for netrin on RGC axon branch initiation as growth cones innervate their target. PMID:21858928

  3. Expression of the immunoglobulin superfamily cell adhesion molecules in the developing spinal cord and dorsal root ganglion.

    PubMed

    Gu, Zirong; Imai, Fumiyasu; Kim, In Jung; Fujita, Hiroko; Katayama, Kei ichi; Mori, Kensaku; Yoshihara, Yoshihiro; Yoshida, Yutaka

    2015-01-01

    Cell adhesion molecules belonging to the immunoglobulin superfamily (IgSF) control synaptic specificity through hetero- or homophilic interactions in different regions of the nervous system. In the developing spinal cord, monosynaptic connections of exquisite specificity form between proprioceptive sensory neurons and motor neurons, however, it is not known whether IgSF molecules participate in regulating this process. To determine whether IgSF molecules influence the establishment of synaptic specificity in sensory-motor circuits, we examined the expression of 157 IgSF genes in the developing dorsal root ganglion (DRG) and spinal cord by in situ hybridization assays. We find that many IgSF genes are expressed by sensory and motor neurons in the mouse developing DRG and spinal cord. For instance, Alcam, Mcam, and Ocam are expressed by a subset of motor neurons in the ventral spinal cord. Further analyses show that Ocam is expressed by obturator but not quadriceps motor neurons, suggesting that Ocam may regulate sensory-motor specificity in these sensory-motor reflex arcs. Electrophysiological analysis shows no obvious defects in synaptic specificity of monosynaptic sensory-motor connections involving obturator and quadriceps motor neurons in Ocam mutant mice. Since a subset of Ocam+ motor neurons also express Alcam, Alcam or other functionally redundant IgSF molecules may compensate for Ocam in controlling sensory-motor specificity. Taken together, these results reveal that IgSF molecules are broadly expressed by sensory and motor neurons during development, and that Ocam and other IgSF molecules may have redundant functions in controlling the specificity of sensory-motor circuits.

  4. Protection of Retinal Ganglion Cells and Retinal Vasculature by Lycium Barbarum Polysaccharides in a Mouse Model of Acute Ocular Hypertension

    PubMed Central

    Mi, Xue-Song; Feng, Qian; Lo, Amy Cheuk Yin; Chang, Raymond Chuen-Chung; Lin, Bin; Chung, Sookja Kim; So, Kwok-Fai

    2012-01-01

    Acute ocular hypertension (AOH) is a condition found in acute glaucoma. The purpose of this study is to investigate the protective effect of Lycium barbarum polysaccharides (LBP) and its protective mechanisms in the AOH insult. LBP has been shown to exhibit neuroprotective effect in the chronic ocular hypertension (COH) experiments. AOH mouse model was induced in unilateral eye for one hour by introducing 90 mmHg ocular pressure. The animal was fed with LBP solution (1 mg/kg) or vehicle daily from 7 days before the AOH insult till sacrifice at either day 4 or day 7 post insult. The neuroprotective effects of LBP on retinal ganglion cells (RGCs) and blood-retinal-barrier (BRB) were evaluated. In control AOH retina, loss of RGCs, thinning of IRL thickness, increased IgG leakage, broken tight junctions, and decreased density of retinal blood vessels were observed. However, in LBP-treated AOH retina, there was less loss of RGCs with thinning of IRL thickness, IgG leakage, more continued structure of tight junctions associated with higher level of occludin protein and the recovery of the blood vessel density when compared with vehicle-treated AOH retina. Moreover, we found that LBP provides neuroprotection by down-regulating RAGE, ET-1, Aβ and AGE in the retina, as well as their related signaling pathways, which was related to inhibiting vascular damages and the neuronal degeneration in AOH insults. The present study suggests that LBP could prevent damage to RGCs from AOH-induced ischemic injury; furthermore, through its effects on blood vessel protection, LBP would also be a potential treatment for vascular-related retinopathy. PMID:23094016

  5. DRP1 inhibition rescues retinal ganglion cells and their axons by preserving mitochondrial integrity in a mouse model of glaucoma.

    PubMed

    Kim, K-Y; Perkins, G A; Shim, M S; Bushong, E; Alcasid, N; Ju, S; Ellisman, M H; Weinreb, R N; Ju, W-K

    2015-01-01

    Glaucoma is the leading cause of irreversible blindness and is characterized by slow and progressive degeneration of the optic nerve head axons and retinal ganglion cell (RGC), leading to loss of visual function. Although oxidative stress and/or alteration of mitochondrial (mt) dynamics induced by elevated intraocular pressure (IOP) are associated with this neurodegenerative disease, the mechanisms that regulate mt dysfunction-mediated glaucomatous neurodegeneration are poorly understood. Using a mouse model of glaucoma, DBA/2J (D2), which spontaneously develops elevated IOP, as well as an in vitro RGC culture system, we show here that oxidative stress, as evidenced by increasing superoxide dismutase 2 (SOD2) and mt transcription factor A (Tfam) protein expression, triggers mt fission and loss by increasing dynamin-related protein 1 (DRP1) in the retina of glaucomatous D2 mice as well as in cultured RGCs exposed to elevated hydrostatic pressure in vitro. DRP1 inhibition by overexpressing DRP1 K38A mutant blocks mt fission and triggers a subsequent reduction of oxidative stress, as evidenced by decreasing SOD2 and Tfam protein expression. DRP1 inhibition promotes RGC survival by increasing phosphorylation of Bad at serine 112 in the retina and preserves RGC axons by maintaining mt integrity in the glial lamina of glaucomatous D2 mice. These findings demonstrate an important vicious cycle involved in glaucomatous neurodegeneration that starts with elevated IOP producing oxidative stress; the oxidative stress then leads to mt fission and a specific form of mt dysfunction that generates further oxidative stress, thus perpetuating the cycle. Our findings suggest that DRP1 is a potential therapeutic target for ameliorating oxidative stress-mediated mt fission and dysfunction in RGC and its axons during glaucomatous neurodegeneration. Thus, DRP1 inhibition may provide a new therapeutic strategy for protecting both RGCs and their axons in glaucoma and other optic

  6. Prolonged elevation of intraocular pressure results in retinal ganglion cell loss and abnormal retinal function in mice

    PubMed Central

    Khan, A Kareem; Tse, Dennis Y; van der Heijden, Meike; Shah, Priya; Nusbaum, Derek; Yang, Zhuo; Wu, Samuel M; Frankfort, Benjamin J

    2014-01-01

    The purpose of this study was to assess the impact of prolonged intraocular pressure (IOP) elevation on retinal anatomy and function in a mouse model of experimental glaucoma. IOP was elevated by anterior chamber injection of a fixed combination of polystyrene beads and sodium hyaluronate, and maintained via re-injection after 24 weeks. IOP was measured weekly with a rebound tonometer for 48 weeks. Histology was assessed with a combination of retrograde labeling and antibody staining. Retinal physiology and function was assessed with dark-adapted electroretinograms (ERGs). Comparisons between bead-injected animals and various controls were conducted at both 24 and 48 weeks after bead injection. IOP was elevated throughout the study. IOP elevation resulted in a reduction of retinal ganglion cell (RGCs) and an increase in axial length at both 24 and 48 weeks after bead injection. The b-wave amplitude of the ERG was increased to the same degree in bead-injected eyes at both time points, similar to previous studies. The positive scotopic threshold response (pSTR) amplitude, a measure of RGC electrical function, was diminished at both 24 and 48 weeks when normalized to the increased b-wave amplitude. At 48 weeks, the pSTR amplitude was reduced even without normalization, suggesting more profound RGC dysfunction. We conclude that injection of polystyrene beads and sodium hyaluronate causes chronic IOP elevation which results in phenotypes of stable b-wave amplitude increase and progressive pSTR amplitude reduction, as well as RGC loss and axial length elongation. PMID:25450059

  7. Evaluation of a Method for Estimating Retinal Ganglion Cell Counts Using Visual Fields and Optical Coherence Tomography

    PubMed Central

    Raza, Ali S.; Hood, Donald C.

    2015-01-01

    Purpose. To evaluate the accuracy and generalizability of a published model that derives estimates of retinal ganglion cell (RGC) counts and relates structural and functional changes due to glaucoma. Methods. Both the Harwerth et al. nonlinear model (H-NLM) and the Hood and Kardon linear model (HK-LM) were applied to an independent dataset of frequency-domain optical coherence tomography and visual fields, consisting of 48 eyes of 48 healthy controls, 100 eyes of 77 glaucoma patients and suspects, and 18 eyes of 14 nonarteritic anterior ischemic optic neuropathy (ION) patients with severe vision loss. Using the coefficient of determination R2, the models were compared while keeping constant the topographic maps, specifically a map by Garway-Heath et al. and a separate map by Harwerth et al., which relate sensitivity test stimulus locations to corresponding regions around the optic disc. Additionally, simulations we