Elevated plasma aldosterone levels are associated with a reduction in retinal ganglion cell survival

Objective: The purpose of this article is to investigate the relationship between the plasma concentration of aldosterone and changes in the number of retinal ganglion cells (RGCs) after systemic administration of aldosterone. Methods: An osmotic minipump that was subcutaneously implanted into the midscapular region of rats administered 40, 80 or 160 μg/kg/day aldosterone or vehicle. Enzyme immunoassay kits were used to measure the plasma aldosterone concentrations two weeks after the systemic administration of aldosterone or vehicle. Six weeks after these systemic administrations, the number of RGCs was measured. Results: The plasma aldosterone concentrations at two weeks after systemic administration of vehicle or 160 μg/kg/day aldosterone were 238 ± 17 pg/ml and 1750 ± 151 pg/ml (748.5% ± 183.2%), respectively. There was a significant decrease in the number of RGCs in the central retina of the rats after the administration of either 80 or 160 μg/kg/day aldosterone. In the peripheral retina, however, there was a significant decrease in the number of RGCs in 40, 80 or 160 μg/kg/day aldosterone. There was a significant correlation between the number of RGCs and plasma aldosterone concentration. Conclusions: After systemic administration of aldosterone, there was a negative correlation between the plasma aldosterone concentration and the number of RGCs.

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The relationship between neurotrophic factors and CaMKII in the death and survival of retinal ganglion cells

Progress in Brain Research - Glaucoma: An Open Window to Neurodegeneration and Neuroprotection ◽

10.1016/s0079-6123(08)01136-9 ◽

2008 ◽

pp. 521-540 ◽

Cited By ~ 9

Author(s):

N.G.F. Cooper ◽

A. Laabich ◽

W. Fan ◽

X. Wang

Keyword(s):

Retinal Ganglion Cells ◽

Neurotrophic Factors ◽

Ganglion Cells ◽

Retinal Ganglion ◽

The Relationship

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The development of the pattern of retinal ganglion cells in the chick retina: mechanisms that control differentiation

Development ◽

10.1242/dev.126.24.5713 ◽

1999 ◽

Vol 126 (24) ◽

pp. 5713-5724 ◽

Cited By ~ 13

Author(s):

K.L. McCabe ◽

E.C. Gunther ◽

T.A. Reh

Keyword(s):

Cell Differentiation ◽

Ganglion Cell ◽

Retinal Ganglion Cells ◽

Ganglion Cells ◽

Receptor Activation ◽

Peripheral Retina ◽

Retinal Ganglion ◽

Fgf Receptor ◽

Chick Retina ◽

Regular Arrays

Neurons in both vertebrate and invertebrate eyes are organized in regular arrays. Although much is known about the mechanisms involved in the formation of the regular arrays of neurons found in invertebrate eyes, much less is known about the mechanisms of formation of neuronal mosaics in the vertebrate eye. The purpose of these studies was to determine the cellular mechanisms that pattern the first neurons in vertebrate retina, the retinal ganglion cells. We have found that the ganglion cells in the chick retina develop as a patterned array that spreads from the central to peripheral retina as a wave front of differentiation. The onset of ganglion cell differentiation keeps pace with overall retinal growth; however, there is no clear cell cycle synchronization at the front of differentiation of the first ganglion cells. The differentiation of ganglion cells is not dependent on signals from previously formed ganglion cells, since isolation of the peripheral retina by as much as 400 μm from the front of ganglion cell differentiation does not prevent new ganglion cells from developing. Consistent with previous studies, blocking FGF receptor activation with a specific inhibitor to the FGFRs retards the movement of the front of ganglion cell differentiation, while application of exogenous FGF1 causes the precocious development of ganglion cells in peripheral retina. Our observations, taken together with those of previous studies, support a role for FGFs and FGF receptor activation in the initial development of retinal ganglion cells from the undifferentiated neuroepithelium peripheral to the expanding wave front of differentiation.

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Abnormally high variability in the uncrossed retinofugal pathway of mice with albino mosaicism

Development ◽

10.1242/dev.101.4.857 ◽

1987 ◽

Vol 101 (4) ◽

pp. 857-867 ◽

Cited By ~ 1

Author(s):

R.W. Guillery ◽

G. Jeffery ◽

B.M. Cattanach

Keyword(s):

Retinal Ganglion Cells ◽

Ganglion Cells ◽

Gene Dosage ◽

Optic Tract ◽

High Variability ◽

Retinal Ganglion ◽

Rare Occurrence ◽

Autosome Translocation ◽

Open Question ◽

The Relationship

Female mice showing albino mosaicism due to an X-autosome translocation [Is(In7;X)Ct] have been studied in order to investigate the relationship between the distribution of melanin and the formation, early in development, of the abnormally small uncrossed retinofugal pathway characteristically found in all albino mammals. Earlier evidence indicates that cells normally bearing melanin play a role in producing the abnormality. In the mosaic mice, the albino gene is expressed in only about half of the cells due to random X-inactivation and the patches of normal and albino cells are extremely small relative to total retinal size (less than 1/50). We argued that if all the cells that would normally bear melanin play a role in producing the albino abnormality then the mosaic mice would have a pathway abnormality, about half the size of that in the albino mice. If, however, only a small patch of these cells plays a role, as has been proposed in earlier studies, then one would expect the size of the uncrossed pathway to be highly variable in the mosaic mice. The size of the uncrossed pathway was assessed by placing horseradish peroxidase in the region of the optic tract and lateral geniculate nucleus unilaterally and then counting the number of retrogradely labelled retinal ganglion cells on the same side. The mosaic mice showed a highly variable uncrossed pathway. In some of the mosaic mice, it was the same size as in the albinos and, in others, it was the same size as in normally pigmented mice. Surprisingly, in a small number of mosaic mice, the uncrossed pathway was larger than normal. Whether this relatively rare occurrence of a supernormal uncrossed pathway is due to the higher gene dosage or to the translocation itself remains an open question.

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The Biomechanical Response of Normal and Glaucoma Human Sclera

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19354 ◽

2010 ◽

Cited By ~ 1

Author(s):

Baptiste Coudrillier ◽

Kristin M. Myers ◽

Thao D. Nguyen

Keyword(s):

Retinal Ganglion Cells ◽

Material Properties ◽

Visual Information ◽

Ganglion Cells ◽

Retinal Ganglion ◽

Progressive Degeneration ◽

Biomechanical Response ◽

Elevated Intraocular Pressure ◽

The Relationship ◽

The Brain

By 2010, 60 million people will have glaucoma, the second leading cause of blindness worldwide [1]. The disease is characterized by a progressive degeneration of the retinal ganglion cells (RGC), a type of neuron that transmits visual information to the brain. It is well know that elevated intraocular pressure (IOP) is a risk factor in the damage to the RGCs [3–5], but the relationship between the mechanical properties of the ocular connective tissue and how it affects cellular function is not well characterized. The cornea and the sclera are collage-rich structures that comprise the outer load-bearing shell of the eye. Their preferentially aligned collagen lamellae provide mechanical strength to resist ocular expansion. Previous uniaxial tension studies suggest that altered viscoelastic material properties of the eye wall play a role in glaucomatous damage [6].

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The Relationship between Visual Field Index and Estimated Number of Retinal Ganglion Cells in Glaucoma

PLoS ONE ◽

10.1371/journal.pone.0076590 ◽

2013 ◽

Vol 8 (10) ◽

pp. e76590 ◽

Cited By ~ 7

Author(s):

Amir H. Marvasti ◽

Andrew J. Tatham ◽

Linda M. Zangwill ◽

Christopher A. Girkin ◽

Jeffrey M. Liebmann ◽

...

Keyword(s):

Visual Field ◽

Retinal Ganglion Cells ◽

Ganglion Cells ◽

Retinal Ganglion ◽

Visual Field Index ◽

The Relationship

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The relationship between light-evoked synaptic excitation and spiking behaviour of salamander retinal ganglion cells.

The Journal of Physiology ◽

10.1113/jphysiol.1995.sp020912 ◽

1995 ◽

Vol 487 (3) ◽

pp. 711-725 ◽

Cited By ~ 37

Author(s):

J S Diamond ◽

D R Copenhagen

Keyword(s):

Retinal Ganglion Cells ◽

Ganglion Cells ◽

Retinal Ganglion ◽

Synaptic Excitation ◽

The Relationship

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Activation of ganglion cells and axon bundles using epiretinal electrical stimulation

Journal of Neurophysiology ◽

10.1152/jn.00750.2016 ◽

2017 ◽

Vol 118 (3) ◽

pp. 1457-1471 ◽

Cited By ~ 27

Author(s):

Lauren E. Grosberg ◽

Karthik Ganesan ◽

Georges A. Goetz ◽

Sasidhar S. Madugula ◽

Nandita Bhaskhar ◽

...

Keyword(s):

Electrical Stimulation ◽

Retinal Ganglion Cells ◽

Large Scale ◽

Ganglion Cells ◽

Propagation Speed ◽

Peripheral Retina ◽

Retinal Ganglion ◽

Central Retina ◽

Axon Bundle ◽

Stimulation Current

Epiretinal prostheses for treating blindness activate axon bundles, causing large, arc-shaped visual percepts that limit the quality of artificial vision. Improving the function of epiretinal prostheses therefore requires understanding and avoiding axon bundle activation. This study introduces a method to detect axon bundle activation on the basis of its electrical signature and uses the method to test whether epiretinal stimulation can directly elicit spikes in individual retinal ganglion cells without activating nearby axon bundles. Combined electrical stimulation and recording from isolated primate retina were performed using a custom multielectrode system (512 electrodes, 10-μm diameter, 60-μm pitch). Axon bundle signals were identified by their bidirectional propagation, speed, and increasing amplitude as a function of stimulation current. The threshold for bundle activation varied across electrodes and retinas, and was in the same range as the threshold for activating retinal ganglion cells near their somas. In the peripheral retina, 45% of electrodes that activated individual ganglion cells (17% of all electrodes) did so without activating bundles. This permitted selective activation of 21% of recorded ganglion cells (7% of expected ganglion cells) over the array. In one recording in the central retina, 75% of electrodes that activated individual ganglion cells (16% of all electrodes) did so without activating bundles. The ability to selectively activate a subset of retinal ganglion cells without axon bundles suggests a possible novel architecture for future epiretinal prostheses. NEW & NOTEWORTHY Large-scale multielectrode recording and stimulation were used to test how selectively retinal ganglion cells can be electrically activated without activating axon bundles. A novel method was developed to identify axon activation on the basis of its unique electrical signature and was used to find that a subset of ganglion cells can be activated at single-cell, single-spike resolution without producing bundle activity in peripheral and central retina. These findings have implications for the development of advanced retinal prostheses.

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Selective activation of ganglion cells without axon bundles using epiretinal electrical stimulation

10.1101/075283 ◽

2016 ◽

Cited By ~ 1

Author(s):

Lauren E. Grosberg ◽

Karthik Ganesan ◽

Georges A. Goetz ◽

Sasidhar Madugula ◽

Nandita Bhaskar ◽

...

Keyword(s):

Electrical Stimulation ◽

Retinal Ganglion Cells ◽

Large Scale ◽

Ganglion Cells ◽

Propagation Speed ◽

Peripheral Retina ◽

Retinal Ganglion ◽

Selective Activation ◽

Central Retina ◽

Axon Bundle

AbstractEpiretinal prostheses for treating blindness activate axon bundles, causing large, arc-shaped visual percepts that limit the quality of artificial vision. Improving the function of epiretinal prostheses therefore requires understanding and avoiding axon bundle activation. This paper introduces a method to detect axon bundle activation based on its electrical signature, and uses the method to test whether epiretinal stimulation can directly elicit spikes in individual retinal ganglion cells without activating nearby axon bundles. Combined electrical stimulation and recording from isolated primate retina were performed using a custom multi-electrode system (512 electrodes, 10 µm diameter, 60 µm pitch). Axon bundle signals were identified by their bi-directional propagation, speed, and increasing amplitude as a function of stimulation current. The threshold for bundle activation varied across electrodes and retinas, and was in the same range as the threshold for activating retinal ganglion cells near their somas. In the peripheral retina, 45% of electrodes that activated individual ganglion cells (17% of all electrodes) did so without activating bundles. This permitted selective activation of 21% of recorded ganglion cells (7% of all ganglion cells) over the array. In the central retina, 75% of electrodes that activated individual ganglion cells (16% of all electrodes) did so without activating bundles. The ability to selectively activate a subset of retinal ganglion cells without axon bundles suggests a possible novel architecture for future epiretinal prostheses.New & NoteworthyLarge-scale multi-electrode recording and stimulation were used to test how selectively retinal ganglion cells can be electrically activated without activating axon bundles. A novel method was developed to identify axon activation based on its unique electrical signature, and used to find that a subset of ganglion cells can be activated at single-cell, single-spike resolution without producing bundle activity, in peripheral and central retina. These findings have implications for the development of advanced retinal prostheses.

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