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Ganglion Cells (ganglion + cell)
Kinds of Ganglion Cells Terms modified by Ganglion Cells Selected AbstractsSecondary Apoptosis of Spiral Ganglion Cells Induced by Aminoglycoside: Fas,Fas Ligand Signaling Pathway,THE LARYNGOSCOPE, Issue 9 2008Woo Yong Bae MD Abstract Objectives/Hypothesis: Hair cell loss results in the secondary loss of spiral ganglion neurons (SGNs), over a period of several weeks. The death of the SGNs themselves results from apoptosis. Previous studies have shown that several molecules are involved in the apoptosis of SGNs that occurred secondary to hair cell loss. However, the precise mechanism of apoptosis of the SGNs remains unclear. The aim of this study was to ascertain the secondary apoptosis of spiral ganglion cells induced by aminoglycoside and to investigate the role of the Fas,FasL signaling pathway using guinea pigs as an experimental animal model. Study Design: Laboratory study using experimental animals. Methods: Guinea pigs weighing 250 to 300 g (n = 21) from 3 to 4 weeks of age were used. Gentamicin (60 ,L) was injected through a cochleostomy site on their left side. At 1 (n = 7), 2 (n = 7), and 3 (n = 7) weeks after gentamicin treatment, their cochleas were obtained from their temporal bone. Hematoxylin and eosin and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling staining were performed to observe apoptosis. To investigate the involvement of the Fas,FasL signaling pathway in the secondary apoptosis of SGNs, we performed reverse transcription-polymerase chain reaction (RT-PCR), western blotting, and immunohistochemistry. Results: A progressive loss of spiral ganglion cells with increasing time after gentamicin treatment was observed on light microscopic examination. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling staining demonstrated induction of apoptotic cell death in SGNs after gentamicin treatment. Expression of FasL increased over time after gentamicin treatment as determined by RT-PCR and western blotting. On immunohistochemical staining, we observed the localization of FasL in the SGNs. The proapoptotic molecules Bax and Bad were increased, but levels of the antiapoptotic molecule Bcl-2 were decreased at increasing survival times after gentamicin treatment on RT-PCR. The gentamicin-treated group displayed initial activation of caspase-8 and increased the cleavage of caspase-3, caspase-8, and PARP protein in a time-dependent manner. Conclusions: The secondary apoptosis of SGNs could be a result of the apoptotic Fas,FasL signaling pathway. Blocking the Fas,FasL signaling pathway could be considered as a method for preventing secondary degeneration of SGNs, and further studies are needed to confirm this. [source] The Distribution of Ganglion Cells in the Equine Retina and its Relationship to Skull MorphologyANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2007K. E. Evans Summary It has recently been reported that a strong correlation exists between the distribution of retinal ganglion cells and nose length in the domestic dog. To determine if this phenomenon occurs in another domestic species with diverse skull morphology, the current study examined the distribution of retinal ganglion cells in 30 horses from a variety of breeds. There was a significant variation in the density of ganglion cells found across the retinae. Breed was a significant predictor for ganglion cell density within the visual streak. A strong positive correlation exists between the density of ganglion cells in the visual streak and nasal length. Significant variation was also seen in the area centralis but did not correlate with any of the recorded skull measurements. The findings of this study provide us with further understanding of the equine visual system and the level of variation that exists between individuals of the same species. [source] Distribution of glycine receptor subunits on primate retinal ganglion cells: a quantitative analysisEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2000Bin Lin Abstract This study investigates the distribution of inhibitory neurotransmitter receptors on sensory neurons. Ganglion cells in the retina of a New World monkey, the common marmoset Callithrix jacchus, were injected with Lucifer yellow and Neurobiotin and subsequently processed with antibodies against one (,1), or against all subunits, of the glycine receptor, or against the anchoring protein gephyrin. Immunoreactive (IR) puncta representing glycine receptor or gephyrin clusters were found on the proximal and the distal dendrites of all ganglion cell types investigated. For both parasol and midget cells, the density of receptor clusters was greater on distal than proximal dendrites for all antibodies tested. In parasol cells the average density for the ,1 subunit of the glycine receptor was 0.087 IR puncta/µm of dendrite, and for all subunits it was 0.119 IR puncta/µm of dendrite. Thus, the majority of glycine receptors on parasol cells contain the ,1 subunit. For parasol cells, we estimated an average of 1.5 glycinergic synapses/100 µm2 dendritic membrane on proximal dendrites and about 9.4 glycinergic synapses/100 µm2 on distal dendrites. The segregation of receptors to the distal dendrites appears to be a common feature of inhibitory neurotransmitter input to parasol and midget cells, and might be associated with the receptive field surround mechanism. [source] Recent clinical findings with memantine should not mean that the idea of neuroprotection in glaucoma is abandonedACTA OPHTHALMOLOGICA, Issue 4 2009Neville N. Osborne Abstract. Loss of vision in primary open-angle glaucoma (glaucoma) is caused by retinal ganglion cells dying at a seemingly steady and variable rate in different patients. Present treatments for all glaucoma patients are inadequate and a goal to rectify this is to discover appropriate drugs or chemicals (neuroprotectants) that can be taken orally to slow down retinal ganglion cell death and have negligible side-effects. It was therefore of great disappointment to learn earlier this year that the one clinical trial conducted to test the efficacy of memantine as a neuroprotectant for glaucoma was unsuccessful. In this article, I consider the mechanisms by which retinal ganglion cells may die in glaucoma and suggest that memantine may have benefited patients taking it but to a level that was difficult to detect with present methodologies. Ganglion cells are induced to die by different triggers in glaucoma, suggesting that neuroprotectants with multiple modes of actions are likely to reveal clearer results than was found for memantine. Therefore, the idea of neuroprotection in glaucoma must not be abandoned. [source] Nociceptin/orphanin FQ inhibits capsaicin-induced guinea-pig airway contraction through an inward-rectifier potassium channelBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2002Yanlin Jia Nociceptin/orphanin FQ (N/OFQ), an endogenous opioid-like orphan receptor (NOP receptor, previously termed ORL1 receptor) agonist, has been found to inhibit capsaicin-induced bronchoconstriction in isolated guinea-pig lungs and in vivo. The underlying mechanisms are not clear. In the present studies, we tested the effect of N/OFQ on VR1 channel function in isolated guinea-pig nodose ganglia cells. Capsaicin increased intracellular Ca2+ concentration in these cells through activation of vanilloid receptors. Capsaicin-induced Ca2+ responses were attenuated by pretreatment of nodose neurons with N/OFQ (1 ,M). N/OFQ inhibitory effect on the Ca2+ response in nodose ganglia cells was antagonized by tertiapin (0.5 ,M), an inhibitor of inward-rectifier K+ channels, but not by verapamil, a voltage gated Ca2+ channel blocker, indicating that an inward-rectifier K+ channel is involved in N/OFQ inhibitory effect. In isolated guinea-pig bronchus, N/OFQ (1 ,M) inhibited capsaicin-induced airway contraction. Tertiapin (0.5 ,M) abolished the N/OFQ inhibition of capsaicin-induced bronchial contraction. Capsaicin (10 ,g) increased pulmonary inflation pressure in the isolated perfused guinea-pig lungs. This response was significantly attenuated by pretreatment with N/OFQ (1 ,M). Tertiapin also abolished the N/OFQ inhibitory effect on capsaicin-induced bronchoconstriction in perfused lungs. Capsaicin increased the release of substance P and neurokinin A from isolated lungs. N/OFQ (1 ,M) blocked the capsaicin-induced tachykinin release. These results indicate that N/OFQ-induced hyperpolarization of tachykinin containing airway sensory nerves, through an inward-rectifier K+ channel activation, accounts for the inhibition of capsaicin-evoked broncoconstriction. British Journal of Pharmacology (2002) 135, 764,770; doi:10.1038/sj.bjp.0704515 [source] Tenascin-R and axon growth-promoting molecules are up-regulated in the regenerating visual pathway of the lizard (Gallotia galloti)DEVELOPMENTAL NEUROBIOLOGY, Issue 7 2008Dirk M. Lang Abstract It is currently unclear whether retinal ganglion cell (RGC) axon regeneration depends on down-regulation of axon growth-inhibitory proteins, and to what extent outgrowth-promoting substrates contribute to RGC axon regeneration in reptiles. We performed an immunohistochemical study of the regulation of the axon growth-inhibiting extracellular matrix molecules tenascin-R and chondroitin sulphate proteoglycan (CSPG), the axon outgrowth-promoting extracellular matrix proteins fibronectin and laminin, and the axonal tenascin-R receptor protein F3/contactin during RGC axon regeneration in the lizard, Gallotia galloti. Tenascin-R and CSPG were expressed in an extracellular matrix-, oligodendrocyte/myelin- and neuron-associated pattern and up-regulated in the regenerating optic pathway. The expression pattern of tenascin-R was not indicative of a role in channeling or restriction of re-growing RGC axons. Up-regulation of fibronectin, laminin, and F3/contactin occurred in spatiotemporal patterns corresponding to tenascin-R expression. Moreover, we analyzed the influence of substrates containing tenascin-R, fibronectin, and laminin on outgrowth of regenerating lizard RGC axons. In vitro regeneration of RGC axons was not inhibited by tenascin-R, and further improved on mixed substrates containing tenascin-R together with fibronectin or laminin. These results indicate that RGC axon regeneration in Gallotia galloti does not require down-regulation of tenascin-R or CSPG. Presence of tenascin-R is insufficient to prevent RGC axon growth, and concomitant up-regulation of axon growth-promoting molecules like fibronectin and laminin may override the effects of neurite growth inhibitors on RGC axon regeneration. Up-regulation of contactin in RGCs suggests that tenascin-R may have an instructive function during axon regeneration in the lizard optic pathway. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008 [source] Ganglion cell regeneration following whole-retina destruction in zebrafishDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2008Tshering Sherpa Abstract The retinas of adult teleost fish can regenerate neurons following injury. The current study provides the first documentation of functional whole retina regeneration in the zebrafish, Danio rerio, following intraocular injection of the cytotoxin, ouabain. Loss and replacement of laminated retinal tissue was monitored by analysis of cell death and cell proliferation, and by analysis of retina-specific gene expression patterns. The spatiotemporal process of retinal ganglion cell (RGC) regeneration was followed through the use of selective markers, and was found to largely recapitulate the spatiotemporal process of embryonic ganglion cell neurogenesis, over a more protracted time frame. However, the re-expression of some ganglion cell markers was not observed. The growth and pathfinding of ganglion cell axons was evaluated by measurement of the optic nerve head (ONH), and the restoration of normal ONH size was found to correspond to the time of recovery of two visually-mediated behaviors. However, some abnormalities were noted, including overproduction of RGCs, and progressive and excessive growth of the ONH at longer recovery times. This model system for whole-retina regeneration has provided an informative view of the regenerative process. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008 [source] GABA and development of the Xenopus optic projectionDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2002Shane C. D. Ferguson Abstract In the developing visual system of Xenopus laevis retinal ganglion cell (RGC) axons extend through the brain towards their major target in the midbrain, the optic tectum. Enroute, the axons are guided along their pathway by cues in the environment. In vitro, neurotransmitters have been shown to act chemotropically to influence the trajectory of extending axons and regulate the outgrowth of developing neurites, suggesting that they may act to guide or modulate the growth of axons in vivo. Previous work by Roberts and colleagues (1987) showed that populations of cells within the developing Xenopus diencephalon and midbrain express the neurotransmitter gamma amino butyric acid (GABA). Here we show that Xenopus RGC axons in the midoptic tract grow alongside the GABAergic cells and cross their GABA immunopositive nerve processes. Moreover, RGC axons and growth cones express GABA-A and GABA-B receptors, and GABA and the GABA-B receptor agonist baclofen both stimulate RGC neurite outgrowth in culture. Finally, the GABA-B receptor antagonist CGP54626 applied to the developing optic projection in vivo causes a dose-dependent shortening of the optic projection. These data indicate that GABA may act in vivo to stimulate the outgrowth of Xenopus RGC axons along the optic tract. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 272,284, 2002 [source] Cooperative effects of bcl-2 and AAV-mediated expression of CNTF on retinal ganglion cell survival and axonal regeneration in adult transgenic miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2006Simone G. Leaver Abstract We used a gene therapy approach in transgenic mice to assess the cooperative effects of combining anti-apoptotic and growth-promoting stimuli on adult retinal ganglion cell (RGC) survival and axonal regeneration following intraorbital optic nerve injury. Bi- cistronic adeno-associated viral vectors encoding a secretable form of ciliary neurotrophic factor and green fluorescent protein (AAV-CNTF-GFP) were injected into eyes of mice that had been engineered to over-express the anti-apoptotic protein bcl-2. For comparison this vector was also injected into wildtype (wt) mice, and both mouse strains were injected with control AAV encoding GFP. Five weeks after optic nerve injury we confirmed that bcl-2 over-expression by itself promoted the survival of axotomized RGCs, but in contrast to previous reports we also saw regeneration of some mature RGC axons beyond the optic nerve crush. AAV-mediated expression of CNTF in adult retinas significantly increased the survival and axonal regeneration of RGCs following axotomy in wt and bcl-2 transgenic mice; however, the effects were greatest in the transgenic strain. Compared with AAV-GFP-injected bcl-2 mice, RGC viability was increased by about 50% (mean, 36 738 RGCs per retina), and over 1000 axons per optic nerve regenerated 1,1.5 mm beyond the crush. These findings exemplify the importance of using a multifactorial therapeutic approach that enhances both neuroprotection and regeneration after central nervous system injury. [source] Early neural activity and dendritic growth in turtle retinal ganglion cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2006Vandana Mehta Abstract Early neural activity, both prenatal spontaneous bursts and early visual experience, is believed to be important for dendritic proliferation and for the maturation of neural circuitry in the developing retina. In this study, we have investigated the possible role of early neural activity in shaping developing turtle retinal ganglion cell (RGC) dendritic arbors. RGCs were back-labelled from the optic nerve with horseradish peroxidase (HRP). Changes in dendritic growth patterns were examined across development and following chronic blockade or modification of spontaneous activity and/or visual experience. Dendrites reach peak proliferation at embryonic stage 25 (S25, one week before hatching), followed by pruning in large field RGCs around the time of hatching. When spontaneous activity is chronically blocked in vivo from early embryonic stages (S22) with curare, a cholinergic nicotinic antagonist, RGC dendritic growth is inhibited. On the other hand, enhancement of spontaneous activity by dark-rearing (Sernagor & Grzywacz (1996)Curr. Biol., 6, 1503,1508) promotes dendritic proliferation in large-field RGCs, an effect that is counteracted by exposure to curare from hatching. We also recorded spontaneous activity from individual RGCs labelled with lucifer yellow (LY). We found a tendency of RGCs with large dendritic fields to be spontaneously more active than small-field cells. From all these observations, we conclude that immature spontaneous activity promotes dendritic growth in developing RGCs. [source] Synaptic contacts between an identified type of ON cone bipolar cell and ganglion cells in the mouse retinaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2005Bin Lin Abstract We surveyed the potential contacts between an identified type of bipolar cell and retinal ganglion cells in the mouse. By crossing two existing mouse strains (line 357 and line GFP-M), we created a double transgenic strain in which GFP is expressed by all members of a single type of ON cone bipolar cell and a sparse, mixed population of retinal ganglion cells. The GFP-expressing bipolar cells appear to be those termed CB4a of Pignatelli & Strettoi [(2004) J. Comp. Neurol., 476, 254,266] and type 7 of Ghosh et al. [(2004) J. Comp. Neurol., 469, 70,82 and J. Comp. Neurol., 476, 202,203]. The labelled ganglion cells include examples of most or all types of ganglion cells present in the mouse. By studying the juxtaposition of their processes in three dimensions, we could learn which ganglion cell types are potential synaptic targets of the line 357 bipolar cell. Of 12 ganglion cell types observed, 10 types could be definitively ruled out as major synaptic targets of the line 357 bipolar cells. One type of monostratified ganglion cell and one bistratified cell tightly cofasciculate with axon terminals of the line 357 bipolar cells. Double labelling for kinesin II demonstrates colocalization of bipolar cell ribbons at the sites of contact between these two types of ganglion cell and the line 357 bipolar cells. [source] Expression of glial fibrillary acidic protein and glutamine synthetase by Müller cells after optic nerve damage and intravitreal application of brain-derived neurotrophic factorGLIA, Issue 2 2002Hao Chen Abstract Müller glia play an important role in maintaining retinal homeostasis, and brain-derived neurotrophic factor (BDNF) has proven to be an effective retinal ganglion cell (RGC) neuroprotectant following optic nerve injury. The goal of these studies was to investigate the relation between optic nerve injury and Müller cell activation, and to determine the extent to which BDNF affects the injury response of Müller cells. Using immunocytochemistry and Western blot analysis, temporal changes in the expression of glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) were examined in rats after optic nerve crush alone, or in conjunction with an intravitreal injection of BDNF (5 ,g). GFAP protein levels were normal at 1 day post-crush, but increased ,9-fold by day 3 and remained elevated over the 2-week period studied. Müller cell GS expression remained stable after optic nerve crush, but the protein showed a transient shift in its cellular distribution; during the initial 24-h period post-crush the GS protein appeared to translocate from the cell body to the inner and outer glial processes, and particularly to the basal endfeet located in the ganglion cell layer. BDNF alone, or in combination with optic nerve crush, did not have a significant effect on the expression of either GFAP or GS compared with the normal retina, or after optic nerve crush alone, respectively. The data indicate that although BDNF is a potent neuroprotectant in the vertebrate retina, it does not appear to have a significant influence on Müller cell expression of either GS or GFAP in response to optic nerve injury. GLIA 38:115,125, 2002. © 2002 Wiley-Liss, Inc. [source] Oligophrenin-1, a Rho GTPase-activating protein (RhoGAP) involved in X-linked mental retardation, is expressed in the enteric nervous systemTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 2 2003Junhua Xiao Abstract Oligophrenin-1 is a RhoGTPase-activating protein (RhoGAP) that is involved in the regulation of shape changes in dendritic spines, and outgrowth of axons and dendrites in the brain. These changes in neuronal morphology are central to the mechanisms of plasticity, learning, and memory. Although the enteric nervous system also exhibits long-term changes in neuronal function, the expression and involvement of oligophrenin-1 has not previously been investigated. We show by RT-PCR analysis that oligophrenin-1 mRNA is expressed in the myenteric plexus (MP) of the guinea pig ileum. Sequencing of RT-PCR products showed that guinea pig oligophrenin-1 mRNA is 98% and 87% homologous to human and mouse oligophrenin-1, respectively, except that a 42 bp sequence is absent from the guinea pig mRNA. This 42 bp sequence codes for a sequence of 14 amino acids located near the carboxy-terminal end of the RhoGAP domain in the human sequence. An antibody that recognizes human oligophrenin-1 identified a 91 kDa protein band in rat and mouse brain lysates and in guinea pig sciatic nerve, and a 36 kDa protein band in both purified enteric ganglion cell and brain lysate from guinea pig. Oligophrenin-1 is localized specifically to neurons and varicose axons in the MPs and submucosal plexuses (SMPs) of the guinea pig and rat, but is not detectable in glial cells, smooth muscle, or other cell types. These findings indicate that oligophrenin-1 is expressed in the enteric nervous system, where it may regulate morphological changes in axons and dendrites, and thus modulate neuronal connectivity. Anat Rec Part A 273A:671,676, 2003. © 2003 Wiley-Liss, Inc. [source] Expression of neuronal markers, synaptic proteins, and glutamine synthetase in the control and regenerating lizard visual systemTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 19 2010M.M. Romero-Alemįn Abstract Spontaneous regrowth of retinal ganglion cell (RGC) axons occurs after optic nerve (ON) transection in the lizard Gallotia galloti. To gain more insight into this event we performed an immunohistochemical study on selected neuron and glial markers, which proved useful for analyzing the axonal regrowth process in different regeneration models. In the control lizards, RGCs were beta-III tubulin- (Tuj1) and HuCD-positive. The vesicular glutamate transporter-1 (VGLUT1) preferentially stained RGCs and glial somata rather than synaptic layers. In contrast, SV2 and vesicular GABA/glycine transporter (VGAT) labeling was restricted to both plexiform layers. Strikingly, the strong expression of glutamine synthetase (GS) in both Müller glia processes and macroglial somata revealed a high glutamate metabolism along the visual system. Upregulation of Tuj1 and HuCD in the surviving RGCs was observed at all the timepoints studied (1, 3, 6, 9, and 12 months postlesion). The significant rise of Tuj1 in the optic nerve head and optic tract (OTr) by 1 and 6 months postlesion, respectively, suggests an increase of the beta-III tubulin transport and incorporation into newly formed axons. Persistent Tuj1+ and SV2+ puncta and swellings were abnormally observed in putative degenerating/dystrophic fibers. Unexpectedly, neuron-like cells of obscure significance were identified in the control and regenerating ON-OTr. We conclude that: 1) the persistent upregulation of Tuj1 and HuCD favors the long-lasting axonal regrowth process; 2) the latter succeeded despite the ectopia and dystrophy of some regrowing fibers; and 3) maintenance of the glutamate-glutamine cycle contributes to the homeostasis and plasticity of the system. J. Comp. Neurol. 518:4067,4087, 2010. © 2010 Wiley-Liss, Inc. [source] Morphology and mosaics of melanopsin-expressing retinal ganglion cell types in miceTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 13 2010David M. Berson Abstract Melanopsin is the photopigment of intrinsically photosensitive retinal ganglion cells (ipRGCs). Melanopsin immunoreactivity reveals two dendritic plexuses within the inner plexiform layer (IPL) and morphologically heterogeneous retinal ganglion cells. Using enhanced immunohistochemistry, we provide a fuller description of murine cell types expressing melanopsin, their contribution to the plexuses of melanopsin dendrites, and mosaics formed by each type. M1 cells, corresponding to the originally described ganglion-cell photoreceptors, occupy the ganglion cell or inner nuclear layers. Their large, sparsely branched arbors (mean diameter 275 ,m) monostratify at the outer limit of the OFF sublayer. M2 cells also have large, monostratified dendritic arbors (mean diameter 310 ,m), but ramify in the inner third of the IPL, within the ON sublayer. There are ,900 M1 cells and 800 M2 cells per retina; each type comprises roughly 1,2% of all ganglion cells. The cell bodies of M1 cells are slightly smaller than those of M2 cells (mean diameters: 13 ,m for M1, 15 ,m for M2). Dendritic field overlap is extensive within each type (coverage factors ,3.8 for M1 and 2.5 for M2 cells). Rare bistratified cells deploy terminal dendrites within both melanopsin-immunoreactive plexuses. Because these are too sparsely distributed to permit complete retinal tiling, they lack a key feature of true ganglion cell types and may be anomalous hybrids of the M1 and M2 types. Finally, we observed weak melanopsin immunoreactivity in other ganglion cells, mostly with large somata, that may constitute one or more additional types of melanopsin-expressing cells. J. Comp. Neurol. 518:2405,2422, 2010. © 2010 Wiley-Liss, Inc. [source] Morphology and mosaics of melanopsin-expressing retinal ganglion cell types in mice,THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 13 2010David M. Berson Abstract Melanopsin is the photopigment of intrinsically photosensitive retinal ganglion cells (ipRGCs). Melanopsin immunoreactivity reveals two dendritic plexuses within the inner plexiform layer (IPL) and morphologically heterogeneous retinal ganglion cells. Using enhanced immunohistochemistry, we provide a fuller description of murine cell types expressing melanopsin, their contribution to the plexuses of melanopsin dendrites, and mosaics formed by each type. M1 cells, corresponding to the originally described ganglion-cell photoreceptors, occupy the ganglion cell or inner nuclear layers. Their large, sparsely branched arbors (mean diameter 275 ,m) monostratify at the outer limit of the OFF sublayer. M2 cells also have large, monostratified dendritic arbors (mean diameter 310 ,m), but ramify in the inner third of the IPL, within the ON sublayer. There are ,900 M1 cells and 800 M2 cells per retina; each type comprises roughly 1,2% of all ganglion cells. The cell bodies of M1 cells are slightly smaller than those of M2 cells (mean diameters: 13 ,m for M1, 15 ,m for M2). Dendritic field overlap is extensive within each type (coverage factors ,3.8 for M1 and 4.6 for M2 cells). Rare bistratified cells deploy terminal dendrites within both melanopsin-immunoreactive plexuses. Because these are too sparsely distributed to permit complete retinal tiling, they lack a key feature of true ganglion cell types and may be anomalous hybrids of the M1 and M2 types. Finally, we observed weak melanopsin immunoreactivity in other ganglion cells, mostly with large somata, that may constitute one or more additional types of melanopsin-expressing cells. J. Comp. Neurol. 518:2405,2422, 2010. © 2010 Wiley-Liss, Inc. [source] Selective projection patterns from subtypes of retinal ganglion cells to tectum and pretectum: Distribution and relation to behaviorTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2009Marcus Robert Jones Abstract An important issue to understand is how visual information can influence the motor system and affect behavior. Using the lamprey (Petromyzon marinus) as an experimental model we examined the morphological subtypes of retinal ganglion cells and their projection pattern to the tectum, which controls eye, head, and body movements, and to the pretectum, which mediates both visual escape responses and the dorsal light response. We identified six distinct morphological types of retinal ganglion cell. Four of these distribute their dendrites in the inner plexiform layer (image forming layer) and project in a retinotopic manner to all areas of the tectum. The posterior part of the retina has the highest density of ganglion cells and projects to the rostral part of the tectum, in which the visual field in front of the lamprey will be represented. From this area both orienting and evasive behaviors can be elicited. In contrast, pretectum receives input from two ganglion cells types that send their dendrites only to the outer plexiform layer or the outer limiting membrane and therefore may directly contact photoreceptors, and transmit information without additional delay to pretectum, which may be particularly important for visual escape responses. One of these two types, the bipolar ganglion cell, is only found in a small patch of retina just ventral of the optic nerve. Due to its distribution, morphology, and projections we suggest that this cell may control the dorsal light response. J. Comp. Neurol. 517:257,275, 2009. © 2009 Wiley-Liss, Inc. [source] Selective projection patterns from subtypes of retinal ganglion cells to tectum and pretectum: Distribution and relation to behaviorTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2009Marcus Robert Jones Abstract An important issue to understand is how visual information can influence the motor system and affect behavior. Using the lamprey (Petromyzon marinus) as an experimental model we examined the morphological subtypes of retinal ganglion cells and their projection pattern to the tectum, which controls eye, head, and body movements, and to the pretectum, which mediates both visual escape responses and the dorsal light response. We identified six distinct morphological types of retinal ganglion cell. Four of these distribute their dendrites in the inner plexiform layer (image forming layer) and project in a retinotopic manner to all areas of the tectum. The posterior part of the retina has the highest density of ganglion cells and projects to the rostral part of the tectum, in which the visual field in front of the lamprey will be represented. From this area both orienting and evasive behaviors can be elicited. In contrast, pretectum receives input from two ganglion cells types that send their dendrites only to the outer plexiform layer or the outer limiting membrane and therefore may directly contact photoreceptors, and transmit information without additional delay to pretectum, which may be particularly important for visual escape responses. One of these two types, the bipolar ganglion cell, is only found in a small patch of retina just ventral of the optic nerve. Due to its distribution, morphology, and projections we suggest that this cell may control the dorsal light response. J. Comp. Neurol. 517:257,275, 2009. © 2009 Wiley-Liss, Inc. [source] Selective projection patterns from subtypes of retinal ganglion cells to tectum and pretectum: Distribution and relation to behaviorTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2009Marcus Robert Jones Abstract An important issue to understand is how visual information can influence the motor system and affect behavior. Using the lamprey (Petromyzon marinus) as an experimental model we examined the morphological subtypes of retinal ganglion cells and their projection pattern to the tectum, which controls eye, head, and body movements, and to the pretectum, which mediates both visual escape responses and the dorsal light response. We identified six distinct morphological types of retinal ganglion cell. Four of these distribute their dendrites in the inner plexiform layer (image forming layer) and project in a retinotopic manner to all areas of the tectum. The posterior part of the retina has the highest density of ganglion cells and projects to the rostral part of the tectum, in which the visual field in front of the lamprey will be represented. From this area both orienting and evasive behaviors can be elicited. In contrast, pretectum receives input from two ganglion cells types that send their dendrites only to the outer plexiform layer or the outer limiting membrane and therefore may directly contact photoreceptors, and transmit information without additional delay to pretectum, which may be particularly important for visual escape responses. One of these two types, the bipolar ganglion cell, is only found in a small patch of retina just ventral of the optic nerve. Due to its distribution, morphology, and projections we suggest that this cell may control the dorsal light response. J. Comp. Neurol. 517:257,275, 2009. © 2009 Wiley-Liss, Inc. [source] Synaptic organization of complex ganglion cells in rabbit retina: Type and arrangement of inputs to directionally selective and local-edge-detector cellsTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2005Edward V. Famiglietti Abstract The type and topographic distribution of synaptic inputs to a directionally selective (DS) rabbit retinal ganglion cell (GC) were examined and were compared with those received by two other complex GC types. The percentage of cone bipolar cell (BC) input, presumably an index of sustained responses and simple receptive field properties, is much higher than expected for complex GCs in reference to previous reports in other species: approximately 20% for the type 1 bistratified ON,OFF DS GC and for a multistratified GC, and approximately 40% for the small-tufted local-edge-detector GC. Consistent with a previous study (Famiglietti [1991] J. Comp. Neurol. 309:40,70), no ultrastructural evidence is found for inhibitory synapses from starburst amacrine cells to the ON,OFF DS GC. The density of inputs to the ON,OFF DS GC is high and rather evenly distributed over the dendritic tree. Clustering of inputs brings excitatory and inhibitory inputs into proximity, but the strict on-path condition of more proximal inhibitory inputs, favoring shunting inhibition, is not satisfied. Prominent BC input and its regional variation suggest that BCs play key roles in DS neural circuitry, both pre- and postsynaptic to the ON,OFF DS GC, according to a bilayer model (Famiglietti [1993] Invest. Ophthalmol. Vis. Sci. 34:S985). Asymmetry of inhibitory amacrine cell input may signify a region on the preferred side of the receptive field, the inhibition-free zone (Barlow and Levick [1965] J. Physiol. (Lond.) 178:477,504), supporting a role for postsynaptic integration in the DS mechanism. Prominent BC input to the local-edge-detector, often without accompanying amacrine cell input, indicates presynaptic integration in forming its trigger feature. J. Comp. Neurol. 484:357,391, 2005. © 2005 Wiley-Liss, Inc. [source] Dose-Dependent Immunohistochemical Changes in Rat Cornea and Retina after Oral Methylphenidate AdministrationANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009E. Tunc Summary Methylphenidate hydrochloride (MPH), more commonly known as Ritalin, is a piperidine derivative and is the drug most often used to treat attention deficit/hyperactivity disorder, one of the most common behavioural disorders of children and young adults. The aim of this study was to investigate dose-dependent immunohistochemical Dopamine 2 receptor (D2) expression and apoptosis in the rat cornea and cornea. In this study, 27 female pre-pubertal Wistar albino rats, divided into three different dose groups (5, 10 and 20 mg/kg) and their control groups, were used. They were treated orally with methylphenidate dissolved in saline solution for 5 days per week during 3 months. At the end of the third month, after perfusion fixation, eye tissue was removed. Paraffin sections were collected for immunohistochemical and terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labelling assay studies. In our study, we observed that the cornea D2 receptor reactivity showed a dose-related increase after MPH treatment, especially in basal cells of the epithelium and a dose-dependent decrease in the retinal ganglion cell which was statistically meaningful. Analysis of the cornea thickness results showed no meaningful difference between groups. Apoptotic cell number showed a meaningful increase in the high dose treated group compared to the other groups of the study. The data suggest that Ritalin has degenerative effect on the important functional part of the eye, such as cornea and retina and its activating dopaminergic mechanism via similar neuronal paths, functionally and structurally, to induce morphological changes. As a result, we believe that this morphological changes negatively effecting functional organization of the affected cornea and retina. [source] 2121: Sustained neuroprotection after a single intravitreal injection of PGJ2 in a rodent model of NAIONACTA OPHTHALMOLOGICA, Issue 2010V TOUITOU Purpose Prostaglandin-J2 (PGJ2) has been proposed as a potential neuroprotective agent. We wanted to evaluate the toxicity/efficacy of a single intravitreal (IVT) injection of PGJ2 in a rodent model of nonarteritic anterior ischemic optic neuropathy (NAION). Methods We used the laser-activated rose Bengal induction method to produce AION in Long-Evans rats. We evaluated IVT-PGJ2 retinal and ON toxicity. Following induction, PGJ2 was IVT-injected in the treatment-group. IVT phosphate-buffered-saline (PBS) was used as control. Functional studies (VEP) were performed at baseline and at 7days post-treatment. Structural studies included immunohistochemical (IHC), electron microscopic (EM) analysis of the optic nerve (ON), and stereologic analysis of retinal ganglion cell (RGC) numbers at30 day 30. Results Toxicity: IVT PGJ2 (5 eyes) did not induce any significant functional/structural changes in the retina or ON of treated animals compared with animals injected with PBS (5 eyes) 30 days post-injection. Efficacy: After a single IVT-injection, day7 VEPs in the PGJ2-treatment group (n=7) had amplitudes 103.6% of baseline, whereas the PBS-treated group (n=6) had VEPs that were 42.4% of the baseline. 30days post-stroke, EM of ON from the treatment-group demonstrated significant preservation of axons and decreased demyelination. Stereological RGCcounts confirmed significant (p<0.04) RGC preservation in PGJ2-treated animals (1462.6 cells/µm2) compared w the stroke+PBS group (1156.5 cells/µm2). Conclusion A single IVT of PGJ2 preserves RGCs and their axons, and provides sustained neuroprotection for at least 1 month following initial ischemic event. [source] Choroidal blood flow and retinal ganglion cell function in early glaucomaACTA OPHTHALMOLOGICA, Issue 2009D MARANGONI Purpose To assess subfoveal choroidal blood flow in patients with early manifest glaucoma (EMG) and to compare blood flow with functional measures of retinal ganglion cell (RGC) integrity. Methods Subfoveal choroidal blood flow was determined by confocal, real-time laser Doppler flowmetry in 25 EMG patients (<-6 dB Humphrey mean deviation, age range: 42-64 years, visual acuity: 0.8-1.0) and in 20 age-matched controls. All patients had a therapeutically (topical beta-blockers with or without a prostaglandin) controlled intraocular pressure (IOP <20 mmHg). Subfoveal choroidal blood volume (ChBVol), velocity (ChBVel) and flow (ChBF) were determined as the average of three 60 sec recordings with changes in the DC < 10% between the recordings (DC measures the intensity of the light scattered by the tissue and red blood cells in the illuminated volume). In all patients and controls pattern electroretinograms (PERGs) were recorded according to a standardized protocol. Results In EMG patients, average ChBVel and ChBF were reduced by 31 and 35%, respectively (p <0.01) compared to control values. No significant difference in ChBVol was found between the two groups. PERG amplitudes were reduced by 40% (p <0.01) in EMG patients compared to controls. No correlation was found between anyone of the choroidal flow parameters and PERG data or IOP values. Conclusion The results suggest a significant alteration of subfoveal choroidal hemodynamics in EMG patients, involving both ChBVel and ChBF. These changes do not appear to be associated with the severity of functional retinal ganglion cell loss. Our findings may have implications for the pathophysiology of early glaucomatous damage and its treatment. [source] Functional analysis of mutants of the optineurin gene, associated with some forms of glaucomaACTA OPHTHALMOLOGICA, Issue 2008D BALASUBRAMANIAN Purpose Mutations in the gene OPTN are associated with normal tension and open angle glaucomas. We have studied the effects of some of these mutations on the cellular biology of retinal ganglion cells, and tried to infer the role of the protein optineurin. Methods We transfected plasmids expressing normal or wild-type (WT) and E50K, R545Q, H26D, and H486R mutant optineurin into a variety of cells such as HeLa, COS-1, retinal pigment epithelial (RPE), and the rat retinal ganglion cell (RGC) line RGC-5, and followed their effects on cell survival by morphologic observation of cells. Expression of optineurin and its mutants was monitored by immunofluorescence staining of cells and by Western blotting. Results The E50K mutant of optineurin, which is associated with the severest phenotype, was seen to selectively induce the death of retinal ganglion cells but not of the other cell lines tested. Neither the wild type cDNA nor the other mutants have any such effect. This cell death induced by E50K OPTN was inhibited by the antioxidants N-acetylcysteine and Trolox. E50K was seen to generate reactive oxygen species (ROS), which were reduced by antioxidants. Coexpression of manganese superoxide dismutase with the E50K mutant abolished ROS production and inhibited cell death. Conclusion E50K optineurin is a gain of function mutant, which has acquired the ability to induce cell death selectively in retinal ganglion cells. This cell death was mediated by oxidative stress. The present findings suggest the possibility of antioxidant use for delaying or controlling some forms of glaucoma. [source] Support for the idea that light is a risk factor in optic neuropathies, like glaucomaACTA OPHTHALMOLOGICA, Issue 2007NN OSBORNE Purpose: Retinal ganglion cell (RGC) axons in the globe contain many mitochondria and it has been hypothesised that light can interact with these organelles to affect RGC survival in glaucoma. Studies on different cell-types were conducted to support such a proposition. Methods: Near confluent cultures of RGC-5 cells, primary rat retinal cultures, fibroblasts with normal (BJhTERT) or mitochondria depleted of mtDNA (rho0) were transferred to incubators containing light (400-760nm; 800-2000 lux; generally 2 days). Some of the cultures were covered with white paper to exclude the light. The cultures were then analysed for cell viability, generation of free radicals (ROS) and for death by apoptosis. Results: Oxidative status and mitochondrial dehydrogenase activity in retinal cultures (-40±5%), RGC-5 cells (-20±4%) and BJhTERT cells (-13±3%) was reduced significantly by light. Light reduced the number of GABA-positive neurones (-42±6%) in retinal cultures. Light caused a 3-5 fold increase in TUNEL-positive cells in primary retinal, RGC-5 and BJhTERT cultures, than in the dark. ROS staining was also clearly elevated by light. The light-induced toxic effect on the different cell types was significantly blunted by antioxidants like vitamin E and lipoic acid. Moreover, light-induced apoptosis was caspase independent but PARP dependent. In contrast, rho0 cells that lacked functional mitochondria were unaffected by light. Conclusions: The present study shows that light can directly affect mitochondrial function to induce apoptosis. This supports the view that light can interact with the many RGC axon mitochondria to affect the viability of GCs and that this may be of significance in the progression of glaucoma. [source] Expression of AP-2, in the developing chick retinaDEVELOPMENTAL DYNAMICS, Issue 11 2008Xiaodong Li Abstract AP-2 is a family of transcription factors that play important roles during embryonic development. Two AP - 2 genes, AP - 2, and AP - 2,, have previously been characterized in chick retina. Here, we demonstrate that a third member of the chicken AP-2 family, AP - 2,, is primarily expressed in the retina and brain, with highest levels at embryonic days 7 to 11. By in situ hybridization and immunohistochemical analysis, we show that AP - 2, RNA and protein are found in a subset of ganglion cells in embryonic chick retina. Co-immunostaining with anti-Brn3a and anti,AP-2, antibodies indicates that approximately one-third of Brn3a-positive ganglion cells express AP-2,. AP - 2, RNA but not AP-2, protein is also found in cells located in the outer half of the inner nuclear layer. The spatial and temporal distribution of AP-2, protein in the retina suggests a transient role in a subset of late-born ganglion cells likely involving axonal trafficking or pathfinding. Developmental Dynamics 237:3210,3221, 2008. © 2008 Wiley-Liss, Inc. [source] Expression patterns of the opsin 5,related genes in the developing chicken retinaDEVELOPMENTAL DYNAMICS, Issue 7 2008Sayuri Tomonari Abstract The opsin gene family encodes G protein,coupled seven-transmembrane proteins that bind to a retinaldehyde chromophore for photoreception. It has been reported that opsin 5 is expressed in mammalian neural tissue, but its function has been elusive. As a first step to understand the function for opsin 5 in the developing eye, we searched for chicken opsin 5 -related genes in the genome by a bioinformatic approach and isolated opsin 5 cDNA fragments from the embryonic retina by RT-PCR. We found that there are three opsin 5,related genes, designated cOpn5m (chicken opsin 5, mammalian type), cOpn5L1 (chicken opsin 5 - like 1), and cOpn5L2 (chicken opsin 5 - like 2), in the chicken genome. Quantitative PCR analysis has revealed that cOpn5m is the most abundant in the developing and early posthatching neural retina. In situ hybridization analysis has shown that cOpn5m is specifically expressed in subsets of differentiating ganglion cells and amacrine cells. These results suggest that the mammalian type opsin 5 may contribute to the development of these retinal cells in the chicken. Developmental Dynamics 237:1910,1922, 2008. © 2008 Wiley-Liss, Inc. [source] Expression of multiple class three semaphorins in the retina and along the path of zebrafish retinal axonsDEVELOPMENTAL DYNAMICS, Issue 10 2007Davon C. Callander Abstract Retinal ganglion cells (RGCs) extend axons that exit the eye, cross the midline at the optic chiasm, and synapse on target cells in the optic tectum. Class three semaphorins (Sema3s) are a family of molecules known to direct axon growth. We undertook an expression screen to identify sema3s expressed in the retina and/or brain close to in-growing RGC axons, which might therefore influence retinal-tectal pathfinding. We find that sema3Aa, 3Fa, 3Ga, and 3Gb are expressed in the retina, although only sema3Fa is present during the time window when the axons extend. Also, we show that sema3Aa and sema3E are present near or at the optic chiasm. Furthermore, sema3C, 3Fa, 3Ga, and 3Gb are expressed in regions of the diencephalon near the path taken by RGC axons. Finally, the optic tectum expresses sema3Aa, 3Fa, 3Fb, and 3Gb. Thus, sema3s are spatiotemporally placed to influence RGC axon growth. Developmental Dynamics 236:2918,2924, 2007. © 2007 Wiley-Liss, Inc. [source] Temporal and spatial expression profiles of the Fat3 protein, a giant cadherin molecule, during mouse developmentDEVELOPMENTAL DYNAMICS, Issue 2 2007Shigenori Nagae Abstract Cadherins constitute a superfamily of cell,cell interaction molecules that participate in morphogenetic processes of animal development. Fat cadherins are the largest members of this superfamily, with 34 extracellular cadherin repeats. Classic Fat, identified in Drosophila, is known to regulate cell proliferation and planar cell polarity. Although 4 subtypes of Fat cadherin, Fat1, Fat2, Fat3, and Fat4/Fat-J, have been identified in vertebrates, their protein localization remains largely unknown. Here we describe the mRNA and protein distributions of Fat3 during mouse development. We found that Fat3 expression was restricted to the nervous system. In the brain, Fat3 was expressed in a variety of regions and axon fascicles. However, its strongest expression was observed in the olfactory bulb and retina. Detailed analysis of Fat3 in the developing olfactory bulb revealed that Fat3 mRNA was mainly expressed by mitral cells and that its proteins were densely localized along the dendrites of these cells as well as in their axons to some extent. Fat3 transcripts in the retina were expressed by amacrine and ganglion cells, and its proteins were concentrated in the inner plexiform layer throughout development. Based on these observations, we suggest that Fat3 plays a role in the interactions between neurites derived from specific subsets of neurons during development. Developmental Dynamics 236:534,543, 2007. © 2006 Wiley-Liss, Inc. [source] A non-canonical photopigment, melanopsin, is expressed in the differentiating ganglion, horizontal, and bipolar cells of the chicken retinaDEVELOPMENTAL DYNAMICS, Issue 3 2005Sayuri Tomonari Abstract Vertebrate melanopsin is a photopigment in the eye, required for photoentrainment. Melanopsin is more closely related to opsin proteins found in invertebrates, than to the other photo-pigments. Although the invertebrate melanopsin-like protein is localized in rhabdomeric photoreceptors in the invertebrate eye, it has been shown to be expressed in a subset of retinal ganglion cells in the mouse and in horizontal cells in the frog, indicating its diversified expression pattern in vertebrates. Here we show that two types of melanopsin transcripts are expressed in the developing chicken retina. Melanopsin is firstly expressed by a small subset of ganglion cells, and then prominently expressed by horizontal cells and later by bipolar cells in the developing chicken retina. This suggests that a subset of ganglion, horizontal, and bipolar cells in the chicken retina may have rhabdomeric properties in their origins. Developmental Dynamics 234:783,790, 2005. © 2005 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||