scholarly journals An ethanolic phosphotungstic acid (EPTA) analysis of photoreceptor and synaptic ultrastructure in the guinea pig retina.

1980 ◽  
Vol 28 (2) ◽  
pp. 142-148 ◽  
Author(s):  
K R Fry ◽  
A W Spira
Keyword(s):  
Guinea Pig ◽  
Phosphotungstic Acid ◽  
Plexiform Layer ◽  
Synaptic Cleft ◽  
Basal Bodies ◽  
Inner Plexiform Layer ◽  
Synaptic Terminal ◽  
Presynaptic Membrane ◽  
Synaptic Ultrastructure ◽  
Plexiform Layers

Ethanolic phosphotungstic acid (EPTA) has been used to elucidate the structure of certain organelles contained within retinal cells not clearly discernible using conventional preparations. Both synaptic and nonsynaptic components of the guinea pig neural retina have been analyzed. Within the photoreceptor (PR) cell EPTA-stained components include the connecting cilia, their basal bodies, and the root filament system. Cross-striated fibrillar organelles, similar in appearance to the root filaments, are also observed in the nuclear region, the synaptic terminal and other parts of the PR cell. The possible structural continuity and significance of these structures are discussed. Within retinal synapses of both the inner and outer plexiform layers, ribbons and associated paramembranous specializations are stained. The photoreceptor ribbons have a trialaminar structure with filamentous, tufted borders. Synaptic cleft material and postsynaptic densities are also stained. Bipolar cell synapses in the inner plexiform layer contain stained short ribbons as well as closely associated peg-like densities extending towards the presynaptic membrane.

The structural and functional development of the retina in larval Xenopus

Development ◽  
1975 ◽  
Vol 33 (4) ◽  
pp. 915-940
Author(s):  
S. H. Chung ◽  
R. Victoria Stirling ◽  
R. M. Gaze
Keyword(s):  
Ganglion Cells ◽  
Single Layer ◽  
Plexiform Layer ◽  
Distinct Pattern ◽  
Inner Plexiform Layer ◽  
Retinal Ganglion ◽  
Response Characteristics ◽  
Functional Development ◽  
New Type ◽  
Plexiform Layers

The structural transformations of the larval Xenopus retina at successive stages of development, and concomitant changes in response characteristics of retinal ganglion cells, were studied using histological and electrophysiological techniques. The first sign of visually evoked electrical responses appears at about the time when the ganglion cells spread out into a single layer and shortly after the inner and outer plexiform layers become discernible. Initially giving simple ‘on’ responses, the cells progressively change their response characteristics and become ‘event’ units. Subsequently, ‘dimming’ units can be identified. Throughout larval life, response properties of these two types become more distinct from one another and approximate to those found in the adult. So do the arborization patterns of the dendritic trees of the ganglion cells. Two types of branching patterns are identifiable in Golgi preparations. Around metamorphic climax, a new type of ganglion cell appears, coinciding with the emergence of ‘sustained’ units electrophysiologically. After metamorphosis, the retina still grows both in thickness (mainly in the inner plexiform layer) and diameter. The three unit types change such that they come to show pronounced inhibitory effects from the peripheral visual field on the receptive field and each unit type acquires a distinct pattern of endogenous discharge.

scholarly journals Distribution of activities of aspartate aminotransferase isoenzymes and malate dehydrogenase in guinea pig retinal layers.

1987 ◽  
Vol 35 (6) ◽  
pp. 669-674 ◽  
Author(s):  
C D Ross ◽  
D A Godfrey
Keyword(s):  
Guinea Pig ◽  
Malate Dehydrogenase ◽  
Aspartate Aminotransferase ◽  
Energy Production ◽  
Outer Nuclear Layer ◽  
Plexiform Layer ◽  
Inner Plexiform Layer ◽  
Retinal Layers ◽  
Metabolic Reactions ◽  
The Difference

Distributions of activity of the cytosolic (cAAT) and mitochondrial (mAAT) isoenzymes of aspartate aminotransferase and of malate dehydrogenase (MDH) were determined in guinea pig retinal layers. The distribution of total AAT activity (tAAT = cAAT + mAAT) and of mAAT activity correlated well (r = 0.88-0.91) with the distribution of MDH activity. mAAT activity was highest in the inner segments of the photoreceptors; there was a greater than twelve-fold difference between activity in that layer and in the inner retinal layers. cAAT activity was also highest in the inner segments, but the difference between the activity in the inner segments and the other layers was not nearly as great as with mAAT. cAAT activity was also relatively high in the outer nuclear layer, outer plexiform layer, and part of the inner plexiform layer. The high activity of cAAT, mAAT, and MDH in the inner segments indicates that all of these enzymes are involved in metabolic reactions related to energy production and/or to photoreceptive processes in the outer segments and, therefore, that the enzymes are probably involved in energy-related metabolism at synapses. However, other functions, including those related to neurotransmission, are not excluded.

Localization of GABA- and GAD-like immunoreactivity in the turtle retina

1989 ◽  
Vol 3 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Lawrence B. Hurd ◽  
William D. Eldred
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cell Layer ◽  
Cell Layer ◽  
Plexiform Layer ◽  
Inner Nuclear Layer ◽  
Acid Decarboxylase ◽  
Inner Plexiform Layer ◽  
Cell Counts ◽  
Double Label ◽  
Plexiform Layers

Abstractγ-aminobutyric acid (GABA) has been reported to be an important neurotransmitter in the retinas of many species. This immunocytochemical study detailed the localization of antigens resembling GABA and glutamic acid decarboxylase (GAD, an enzyme involved in the synthesis of GABA), in retinal neurons in the turtle, Pseudemys scripta elegans. GABA-like immunoreactivity was present within somata in the inner and outer regions of the inner nuclear layer, within somata in the ganglion cell layer, and in processes in the outer plexiform layer, inner plexiform layer, and ganglion cell axon layer. GAD-like immunoreactivity was found in somata in the inner and outer regions of the inner nuclear layer and in processes in the inner and outer plexiform layers. Cell counts indicated more somata with GABA-like than GAD-like immunoreactivity in the inner nuclear layer. Double-label studies showed that every somata in the inner nuclear layer which had GAD-like immunoreactivity also had GABA-like immunoreactivity, but that many somata had only GABA-like immunoreactivity.The stratification of immunoreactivity within the inner plexiform layer was analyzed using a scanning densitometer. We described the strata within the inner plexiform layer such that S0 represented the inner nuclear layer/inner plexiform layer border and S100 represented the inner plexiform layer/ganglion cell layer border. Analysis of GAD-like labeling yielded seven distinct strata with peak densities at positions S8, S19, S28, S42, S59, S75, and S93. GABA-like labeling provided five distinct strata with peak densities at positions S17, S28, S67, S84, and S95. The strata with peaks of GABA-like immunoreactivity at S17 and S28 were in statistically identical locations to corresponding strata with GAD-like immunoreactivity. The strata with GABA-like immunoreactivity at S67, S84, and S95 did not have statistically identical peaks of correlated GAD-like immunoreactivity, although there were corresponding strata with GAD-like immunoreactivity nearby. Antiserum directed against GABA failed to produce labeled strata at positions corresponding to the strata with GAD-like immunoreactivity at S8 and S42.In summary, our results indicated that the antisera we used, which were directed against GABA and GAD, produced significantly different labeling in the inner nuclear layer, inner plexiform layer, and the ganglion cell body and axon layers of the turtle retina. Until the physiological significance of these differences is resolved, studies employing these markers to investigate the function of GABA in the turtle retina should be interpreted with caution.

The Structural Basis of Synaptic Transmitter Release

1976 ◽  
Vol 34 ◽  
pp. 2-3
Author(s):  
Karl H. Pfenninger
Keyword(s):  
Plasma Membranes ◽  
Phosphotungstic Acid ◽  
Synaptic Cleft ◽  
Structural Basis ◽  
Junctional Complex ◽  
Target Cells ◽  
Bismuth Iodide ◽  
Synaptic Ultrastructure ◽  
Neurotransmitter Substances ◽  
Junctional Structure

For intercellular transfer of signals, neurons form long processes to contact and form junctions with selected target cells or specific parts thereof. At these sites, they release in a quantal fashion neurotransmitter substances which interact with the receptors of the target cells. Thus, synaptic ultrastructure bears the characteristics of a secreting cellular region combined with those of a junctional complex.Synaptic junctional structure consists of a set of cytoplasmic and cleft (i.e., extracellular) elements which are formed by proteinaceous and (in the cleft) carbohydrate-bearing components anchored in the joined plasma membranes. The synaptic cleft is filled with two layers of material that can be stained with cytochemical techniques such as ethanolic phosphotungstic acid (E-PTA) and bismuth-iodide (BIUL; for review, see 1).

scholarly journals Light-evoked increases in extracellular K+ in the plexiform layers of amphibian retinas.

1985 ◽  
Vol 86 (2) ◽  
pp. 189-213 ◽  
Author(s):  
C J Karwoski ◽  
E A Newman ◽  
H Shimazaki ◽  
L M Proenza
Keyword(s):  
Plexiform Layer ◽  
Wave Generation ◽  
Outer Plexiform Layer ◽  
Aminobutyric Acid ◽  
Electrode Placement ◽  
Inner Plexiform Layer ◽  
Gamma Aminobutyric Acid ◽  
Slice Preparation ◽  
K Concentration ◽  
Plexiform Layers

Recordings of light-evoked changes in extracellular K+ concentration (delta[K+]o) were obtained in the retinas of frog and mudpuppy. In eyecup preparations, various recording approaches were used and provided evidence for a K increase near the outer plexiform layer (distal K increase). This distal K increase could be pharmacologically dissociated from the well-known, large K increase in the proximal retina by the application of ethanol and gamma-aminobutyric acid. The distal K increase also often showed surround antagonism. A retinal slice preparation was used to permit electrode placement into the desired retinal layers under direct visual control and without the risk of electrode damage to adjacent layers. In the slice, a distinct distal K increase was found in the outer plexiform layer, in addition to the prominent K increase in the inner plexiform layer. Compared with eyecups, only weak K increases were found in the nuclear layers of the slice. This suggests that the K responses observed in the nuclear layers of eyecups may be generated by K+ diffusing along the electrode track from the plexiform layers. In the context of current models of ERG b-wave generation, the magnitude of the recorded distal K increase, compared with the proximal K increase, seems too small to give rise to the b-wave. However, the distal K increase may be differentially depressed by electrode dead space. It is also possible that if certain aspects of the models of b-wave generation were modified, then the observed distal K increase could give rise to the b-wave.

Biplexiform ganglion cells, characterized by dendrites in both outer and inner plexiform layers, are regular, mosaic-forming elements of teleost fish retinae

1996 ◽  
Vol 13 (3) ◽  
pp. 517-528 ◽  
Author(s):  
J. E. Cook ◽  
S. L. Kondrashev ◽  
T. A. Podugolnikova
Keyword(s):  
Teleost Fish ◽  
Nearest Neighbor ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Retrograde Transport ◽  
Inner Plexiform Layer ◽  
Regular Elements ◽  
Average Size ◽  
Hexagrammos Stelleri ◽  
Plexiform Layers

AbstractBiplexiform ganglion cells were labelled by retrograde transport of HRP in five species of marine fish from the neoteleost acanthopterygian orders Perciformes and Scorpaeniformes. Their forms and spatial distributions were studied in retinal flatmounts and thick sections. Biplexiform ganglion cells possessed sparsely branched, often varicose, dendrites that ramified through the inner nuclear layer (INL) to reach the outer plexiform layer (OPL), as well as conventional arborizations in the most sclerad part of the inner plexiform layer (IPL). Their somata were of above-average size and were displaced into the vitread border of the INL. Mean soma areas ranged from 99 ± 6 μm2 in Bathymaster derjugini (Perciformes) to 241 ± 12 μm2 in Hexagrammos stelleri (Scorpaeniformes), but were similar in each species to those of the outer-stratified alpha-like ganglion cells, whose dendritic trees occupied the same IPL sublamina. In the best-labelled specimens, biplexiform cells formed clear mosaics with spacings and degrees of regularity much like those of other large ganglion cells, but spatially independent of them. Biplexiform mosaics were plotted in three species, and analyzed by nearest-neighbor distance and spatial correlogram methods. The exclusion radius, an estimate of minimum mosaic spacing, ranged from 113 urn in Hexagrammos stelleri, through 150 μm in Ernogrammus hexagraminus (Perciformes), to 240 μm in Myoxocephalus stelleri (Scorpaeniformes). A spatial cross-correlogram analysis of the distributions of biplexiform and outer-stratified alpha-like cells in Hexagrammos demonstrated the spatial independence of their mosaics. Similar cells were previously observed not only in the freshwater cichlid Oreochromis spilurus (Perciformes) but also in the goldfish Carassius auratiis (Cypriniformes) which, being an ostariophysan teleost, is only distantly related. Thus, biplexiform ganglion cells may be regular elements of all teleost fish retinae. Their functional role remains unknown.

Distribution of GABA immunoreactivity in the cat retina: A light- and electron-microscopic study

1989 ◽  
Vol 2 (5) ◽  
pp. 425-435 ◽  
Author(s):  
Roberta G. Pourcho ◽  
Michael T. Owczarzak
Keyword(s):  
Ganglion Cells ◽  
Feedback Inhibition ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Inner Plexiform Layer ◽  
Electron Microscopic ◽  
Cat Retina ◽  
Plexiform Layers ◽  
Major Target

AbstractThe distribution of GABA-like immunoreactivity in the cat retina was studied through the use of preembedding immunocytochemistry for light microscopy and by postembedding immunogold techniques for electron microscopy. Staining was observed in both inner and outer plexiform layers. Approximately 30% of the somata in the amacrine portion of the inner nuclear layer were immunoreactive and included amacrine and interplexiform cells. Horizontal cells and a subpopulation of cone bipolar cells were also stained. In the ganglion cell layer, staining was observed in both small- and medium-sized neurons. GABA-labeled amacrine cells were presynaptic to somata of amacrine cells and to dendrites of amacrine, bipolar, and ganglion cells. Bipolar cells were a major target, receiving more than 60% of all labeled synapses in the inner plexiform layer. Many of these contacts were reciprocal synapses. These findings support a major role for GABA-labeled amacrines in providing feedback inhibition to bipolar cells in the inner retina.

Neurotransmitter-specific identification and characterization of neurons in the all-cone retina of Anolis carolinensis, I: Gamma-aminobutyric acid

1992 ◽  
Vol 8 (6) ◽  
pp. 515-529 ◽  
Author(s):  
David M. Sherry ◽  
Robert J. Ulshafer
Keyword(s):  
Amacrine Cell ◽  
Ganglion Cell Layer ◽  
Cell Layer ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Anolis Carolinensis ◽  
Gaba Uptake ◽  
Inner Plexiform Layer ◽  
Gamma Aminobutyric Acid ◽  
Plexiform Layers

AbstractThe inhibitory amino-acid neurotransmitter, gamma-aminobutyric acid (GABA), was localized in the pure cone retina of the lizard Anolis carolinensis by autoradiographic and immunocytochemical techniques. Uptake of [3H]-GABA labeled horizontal cells, amacrine cells, numerous cells in the ganglion cell layer, both plexiform layers, and the nerve fiber layer. Label in the inner plexiform layer showed distinct lamination.The pattern of GABA immunoreactivity was similar to the pattern of [3H]-GABA uptake, although some differences, particularly in labeling of amacrine and ganglion cells, were observed. Immunocytochemistry revealed endogenous stores of GABA in a set of horizontal cells, amacrine cells, and cells in the ganglion cell layer. Both plexiform layers were labeled by the GABA antisera. Labeling in the inner plexiform layer (IPL) was highly stratified and GABA-immunoreactive strata were present in both sublaminae a and b. Six subtypes of conventionally placed GABA-immunoreactive amacrine cells and one displaced amacrine cell subtype were identified. Three of the six conventional amacrine cell subtypes were of pyriform morphology and three subtypes were of multipolar morphology. GABA-immunoreactive interstitial cells also were observed.Under certain conditions the GABA antiserum labeled the cones. Etching the resin eliminated cone labeling, suggesting that GABA in the cones is present in a labile pool, unlike GABA in horizontal or amacrine cells, or the observed labeling was not due to endogenous GABA. Cones did not demonstrate [3H]-GABA uptake.

scholarly journals Dopaminergic and GABAergic amacrine cells are direct targets of melatonin: Immunocytochemical study of mt1 melatonin receptor in guinea pig retina

2000 ◽  
Vol 17 (1) ◽  
pp. 63-70 ◽  
Author(s):  
HIROKI FUJIEDA ◽  
JUDITE SCHER ◽  
SOHEILA A. HAMADANIZADEH ◽  
ELLEN WANKIEWICZ ◽  
SHIU F. PANG ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Ganglion Cells ◽  
Neuronal Cell ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell Types ◽  
Inner Plexiform Layer ◽  
Melatonin Receptor ◽  
Western Blots ◽  
Double Immunolabeling

Distribution of the mt1 melatonin receptor in the guinea pig retina was immunocytochemically investigated using peptide-specific anti-mt1 receptor antibody. Western blots of the guinea pig retina showed a single band at approximately 37 kilodalton (kD) immunoreactive to the anti-mt1 antibody. The most intense immunoreactivity for the mt1 receptor was detected in the cell bodies of ganglion cells. Their dendrites and axons were also immunolabeled. Subpopulations of amacrine cells, the inner plexiform layer, and the outer plexiform layer also exhibited moderate to weak immunolabeling. The mt1-positive amacrine cells were located either at the vitreal border of the inner nuclear layer or displaced in the ganglion cell layer. Double immunolabeling using antibodies to the mt1 receptor and tyrosine hydroxylase revealed that the majority of dopaminergic amacrine cells showed mt1 immunoreactivity. Almost all the 1CA type dopaminergic cells were mt1 positive while the 2CA type cells less frequently exhibited mt1 immunoreaction. By double immunolabeling for the mt1 receptor and GABA, more than 50% of the mt1-immunoreactive amacrine cells were shown to be GABAergic neurons. Approximately one-third of the GABAergic amacrine cells were immunolabeled for the mt1 receptor. The present results demonstrate expression of the mt1 receptor in diverse neuronal cell types in the guinea pig retina and provide the first evidence for the direct effect of melatonin on dopaminergic and GABAergic amacrine cells via the mt1 receptor.

Inner Retinal Morphology and Visual Outcomes in Idiopathic Epiretinal Membrane Surgery: A Retrospective Optical Coherence Tomography Study

2021 ◽  
pp. 247412642198961
Author(s):  
Ioannis S. Dimopoulos ◽  
Michael Dollin
Keyword(s):  
Optical Coherence Tomography ◽  
Epiretinal Membrane ◽  
Strong Predictor ◽  
Plexiform Layer ◽  
Inner Plexiform Layer ◽  
Optical Coherence ◽  
Visual Outcomes ◽  
Retinal Pathology

Purpose: Epiretinal membrane (ERM) is a common retinal finding for patients older than 50 years. Disorganization of the retinal inner layers (DRIL) has emerged as a novel predictor of poor visual acuity (VA) in eyes with inner retinal pathology. The aim of our study is to correlate preoperative DRIL with visual outcomes after ERM surgery. Methods: Medical records and optical coherence tomography (OCT) images of 81 pseudophakic patients who underwent treatment of idiopathic ERM were reviewed. Preoperative DRIL on OCT was correlated with VA at baseline and at 3 and 6 months after ERM surgery. DRIL was defined as the loss of distinction between the ganglion cell–inner plexiform layer complex, inner nuclear layer, and outer plexiform layer. DRIL severity was based on its extent within the central 2-mm region of a transfoveal B-scan (absent/mild: <one-third, severe: >one-third horizontal width). Results: Review of preoperative OCT showed severe DRIL in 41% and absent/mild DRIL in 59%. Severe DRIL was associated with worse baseline VA ( P < .001). Preoperative VA and DRIL status at baseline were both predictors of postoperative VA at follow-up time points ( P < .001). Severe DRIL was associated with significantly less improvement in VA at 6 months (–0.23 logMAR for absent/mild vs –0.14 for severe DRIL). Conclusions: Presence of severe preoperative DRIL correlates with worse baseline VA in patients with ERM and reduced VA improvement at 6 months. DRIL can be a strong predictor of long-term poor visual outcomes in ERM surgery.

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