Down-regulation of Glutamate-induced Conductances of Retinal Horizontal Cells After Ganglion Cell Axotomy

2002 ◽  
Vol 75 (2) ◽  
pp. 209-216 ◽  
Author(s):  
RomÁn Blanco ◽  
Francisco Germain ◽  
Almudena Velasco ◽  
Pedro de la Villa
Keyword(s):  
Ganglion Cell ◽  
Horizontal Cells ◽  
Down Regulation

The Retina of Asian and African Elephants: Comparison of Newborn and Adult

2017 ◽  
Vol 89 (2) ◽  
pp. 84-103 ◽  
Author(s):  
Heidrun Kuhrt ◽  
Andreas Bringmann ◽  
Wolfgang Härtig ◽  
Gudrun Wibbelt ◽  
Leo Peichl ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Ganglion Cell ◽  
Glial Cells ◽  
Ganglion Cells ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Retinal Ganglion ◽  
Terrestrial Mammals ◽  
Contrast Perception ◽  
First Time

Elephants are precocial mammals that are relatively mature as newborns and mobile shortly after birth. To determine whether the retina of newborn elephants is capable of supporting the mobility of elephant calves, we compared the retinal structures of 2 newborn elephants (1 African and 1 Asian) and 2 adult animals of both species by immunohistochemical and morphometric methods. For the first time, we present here a comprehensive qualitative and quantitative characterization of the cellular composition of the newborn and the adult retinas of 2 elephant species. We found that the retina of elephants is relatively mature at birth. All retinal layers were well discernible, and various retinal cell types were detected in the newborns, including Müller glial cells (expressing glutamine synthetase and cellular retinal binding protein; CRALBP), cone photoreceptors (expressing S-opsin or M/L-opsin), protein kinase Cα-expressing bipolar cells, tyrosine hydroxylase-, choline acetyltransferase (ChAT)-, calbindin-, and calretinin-expressing amacrine cells, and calbindin-expressing horizontal cells. The retina of newborn elephants contains discrete horizontal cells which coexpress ChAT, calbindin, and calretinin. While the overall structure of the retina is very similar between newborn and adult elephants, various parameters change after birth. The postnatal thickening of the retinal ganglion cell axons and the increase in ganglion cell soma size are explained by the increase in body size after birth, and the decreases in the densities of neuronal and glial cells are explained by the postnatal expansion of the retinal surface area. The expression of glutamine synthetase and CRALBP in the Müller cells of newborn elephants suggests that the cells are already capable of supporting the activities of photoreceptors and neurons. As a peculiarity, the elephant retina contains both normally located and displaced giant ganglion cells, with single cells reaching a diameter of more than 50 µm in adults and therefore being almost in the range of giant retinal ganglion cells found in aquatic mammals. Some of these ganglion cells are displaced into the inner nuclear layer, a unique feature of terrestrial mammals. For the first time, we describe here the occurrence of many bistratified rod bipolar cells in the elephant retina. These bistratified bipolar cells may improve nocturnal contrast perception in elephants given their arrhythmic lifestyle.

Functional Circuitry for Peripheral Suppression in Mammalian Y-Type Retinal Ganglion Cells

2007 ◽  
Vol 97 (6) ◽  
pp. 4327-4340 ◽  
Author(s):  
Kareem A. Zaghloul ◽  
Michael B. Manookin ◽  
Bart G. Borghuis ◽  
Kwabena Boahen ◽  
Jonathan B. Demb
Keyword(s):  
Receptive Field ◽  
Ganglion Cell ◽  
Voltage Clamp ◽  
Ganglion Cells ◽  
Glutamate Release ◽  
High Spatial Frequency ◽  
Amacrine Cells ◽  
Horizontal Cells ◽  
Retinal Ganglion

A retinal ganglion cell receptive field is made up of an excitatory center and an inhibitory surround. The surround has two components: one driven by horizontal cells at the first synaptic layer and one driven by amacrine cells at the second synaptic layer. Here we characterized how amacrine cells inhibit the center response of on- and off-center Y-type ganglion cells in the in vitro guinea pig retina. A high spatial frequency grating (4–5 cyc/mm), beyond the spatial resolution of horizontal cells, drifted in the ganglion cell receptive field periphery to stimulate amacrine cells. The peripheral grating suppressed the ganglion cell spiking response to a central spot. Suppression of spiking was strongest and observed most consistently in off cells. In intracellular recordings, the grating suppressed the subthreshold membrane potential in two ways: a reduced slope (gain) of the stimulus-response curve by ∼20–30% and, in off cells, a tonic ∼1-mV hyperpolarization. In voltage clamp, the grating increased an inhibitory conductance in all cells and simultaneously decreased an excitatory conductance in off cells. To determine whether center response inhibition was presynaptic or postsynaptic (shunting), we measured center response gain under voltage-clamp and current-clamp conditions. Under both conditions, the peripheral grating reduced center response gain similarly. This result suggests that reduced gain in the ganglion cell subthreshold center response reflects inhibition of presynaptic bipolar terminals. Thus amacrine cells suppressed ganglion cell center response gain primarily by inhibiting bipolar cell glutamate release.

scholarly journals S-Potentials in the Skate Retina

1971 ◽  
Vol 58 (2) ◽  
pp. 163-189 ◽  
Author(s):  
John E. Dowling ◽  
Harris Ripps
Keyword(s):  
Membrane Potential ◽  
Ganglion Cell ◽  
Dark Adaptation ◽  
Membrane Potentials ◽  
Horizontal Cells ◽  
Photic Stimulation ◽  
Visual Adaptation ◽  
Cell Discharge ◽  
Background Fields ◽  
Potential Level

The S-potentials recorded intracellularly from the all-rod retina of the skate probably arise from the large horizontal cells situated directly below the layer of receptors. These cells hyperpolarize in response to light, irrespective of stimulus wavelength, and the responses in photopic as well as scotopic conditions were found to be subserved by a single photopigment with λmax = 500 nm. The process of adaptation was studied by recording simultaneously the threshold responses and membrane potentials of S-units during both light and dark adaptation. The findings indicate that the sensitivity of S-units, whether measured upon steady background fields or in the course of dark adaptation, exhibits changes similar to those demonstrated previously for the ERG b-wave and ganglion cell discharge. However, the membrane potential level of the S-unit and its sensitivity to photic stimulation varied independently for all the adapting conditions tested. It appears, therefore, that visual adaptation in the skate retina occurs before the S-unit is reached, i.e., at the receptors themselves.

Neurotransmitter-specific identification and characterization of neurons in the all-cone retina of Anolis carolinensis II: Glutamate and aspartate

1992 ◽  
Vol 9 (3-4) ◽  
pp. 313-323 ◽  
Author(s):  
David M. Sherry ◽  
Robert J. Ulshafer
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cells ◽  
Müller Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Anolis Carolinensis ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Muller Cells

AbstractImmunocytochemical and autoradiographic methods were used to identify neurons in the pure cone retina of the lizard (Anolis carolinensis) that are likely to employ glutamate (GLU) or aspartate (ASP) as a neurotransmitter.GLU immunocytochemistry demonstrated high levels of endogenous GLU in all cone types and numerous bipolar cells. Moderate GLU levels were found in horizontal and ganglion cells. Müller cells and most amacrine cells had very low GLU levels. GLU immunoreactivity (GLU-IR) in the cones was present from the inner segment to the synaptic pedicle. A large spherical cell type with moderate GLU-IR was identified in the proximal inner plexiform layer (IPL). These cells also contain ASP and have been tentatively identified as amacrine cells. Uptake of [3H]-L-GLU labeled all retinal layers. All cone types and Müller cells sequestered [3H]-D-ASP, a substrate specific for the GLU transporter.Anti-ASP labeling was observed in cones, horizontal cells, amacrine cells, and cells in the ganglion cell layer. ASP immunoreactivity (ASP-IR) in the cones was confined to the inner segment. One ASP-containing pyriform amacrine cell subtype ramifying in IPL sublamina b was identified.Analysis of GLU-IR, ASP-IR, and GABA-IR on serial sections indicated that there were two distinct populations of horizontal cells in the Anolis retina: one containing GABA-IR, GLU-IR, and ASP-IR; and another type containing only GLU-IR and ASP-IR. Light GLU-IR was frequently found in GABA-containing amacrine cells but ASP-IR was not.The distinct distributions of GLU and ASP may indicate distinctly different roles for these amino acids. GLU, not ASP, is probably the major neurotransmitter in the cone-biploar-ganglion cell pathway of the Anolis retina. Both GLU and ASP are present in horizontal cells and specific subpopulations of amacrine cells, but it is unclear if GLU or ASP have a neurotransmitter role in these cells.

scholarly journals Weber and noise adaptation in the retina of the toad Bufo marinus.

1990 ◽  
Vol 95 (4) ◽  
pp. 733-753 ◽  
Author(s):  
K Donner ◽  
D R Copenhagen ◽  
T Reuter
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cells ◽  
Statistical Significance ◽  
Gain Control ◽  
Cell Types ◽  
Horizontal Cells ◽  
Background Intensity ◽  
Threshold Response ◽  
Signal Light ◽  
Toad Bufo

Responses to flashes and steps of light were recorded intracellularly from rods and horizontal cells, and extracellularly from ganglion cells, in toad eyecups which were either dark adapted or exposed to various levels of background light. The average background intensities needed to depress the dark-adapted flash sensitivity by half in the three cell types, determined under identical conditions, were 0.9 Rh*s-1 (rods), 0.8 Rh*s-1 (horizontal cells), and 0.17 Rh*s-1 (ganglion cells), where Rh* denotes one isomerization per rod. Thus, there is a range (approximately 0.7 log units) of weak backgrounds where the sensitivity (response amplitude/Rh*) of rods is not significantly affected, but where that of ganglion cells (1/threshold) is substantially reduced, which implies that the gain of the transmission from rods to the ganglion cell output is decreased. In this range, the ganglion cell threshold rises approximately as the square root of background intensity (i.e. in proportion to the quantal noise from the background), while the maintained rate of discharge stays constant. The threshold response of the cell will then signal light deviations (from a mean level) of constant statistical significance. We propose that this type of ganglion cell desensitization under dim backgrounds is due to a post-receptoral gain control driven by quantal fluctuations, and term it noise adaptation in contrast to the Weber adaptation (desensitization proportional to the mean background intensity) of rods, horizontal cells, and ganglion cells at higher background intensities.

Spatiotemporal Patterns at the Retinal Output

1998 ◽  
Vol 80 (1) ◽  
pp. 447-451 ◽  
Author(s):  
Adam L. Jacobs ◽  
Frank S. Werblin
Keyword(s):  
Ganglion Cell ◽  
Response Pattern ◽  
Ganglion Cells ◽  
Cell Activity ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Spatiotemporal Patterns ◽  
Horizontal Cells ◽  
Aminobutyric Acid ◽  
Edge Enhancement

Jacobs, Adam L. and Frank S. Werblin. Spatiotemporal patterns at the retinal output. J. Neurophysiol. 80: 447–451, 1998. Edge enhancement in the retina is thought to be mediated by classical center-surround antagonism, first encountered as the interactions between horizontal cells and cones. But in the salamander retina these interactions do little to enhance edges. Instead, a robust dynamic interaction between amacrine and bipolar cells appears to be responsible for a sharp edge enhancement. To demonstrate this we recorded extracellularly from a single ganglion cell and moved a flashed square, 300 μm on a side, over a 1.5 × 1.0 mm2 grid at 25-μm increments. Playing back all of these recordings simultaneously simulated the pattern of responses that would have been measured from an array of ganglion cells. The emerging pattern of ganglion cell activity first faithfully represented the flashed square, but after ∼60 ms the center of the representation collapsed, leaving a representation of only the edges. We inferred that the feedback synapse from amacrine to bipolar cells at γ-aminobutyric acid-C (GABAC) receptors mediated this effect: bicuculline and strychnine were ineffective in altering the response pattern, but in picrotoxin the center of the representation did not collapse. The GABAergic amacrine cells thought to mediate this effect have quite narrow spread of processes, so the existence of this edge-enhancing effect suggests a mechanism quite different from classical lateral inhibition, namely the delayed inhibition of a spatially expanding input pattern.

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