scholarly journals Ultrastructural Circuitry in Retinal Cell Transplants to Rat Retina

1994 ◽  
Vol 5 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Charles L. Zucker ◽  
Berndt Ehinger ◽  
Magdalene Seiler ◽  
Robert B. Aramant ◽  
Alan R. Adolph

The development of five transplants of fetal retinal tissue to adult rat eyes was examined with the electron microscope. The transplants were of 9 to 10 weeks total age after conception in four cases and 20 weeks in one case. They were at stage E15 when transplanted. Transplants developed in both the epiretinal and subretinal spaces.The transplants were heterogeneously developed with some parts showing almost normal differentiation and others little. Subretinal transplants examined in this study were more developed than epiretinal grafts. Photoreceptor cells developed both inner and outer segments. Their synaptic terminals possessed output ribbon synapses with postsynaptic processes similar to those seen in normal retinas. In regions corresponding to the inner plexiform layer, the adult complement of synapses was seen, including advanced features such as serial synapses as well as reciprocal synapses at bipolar cell dyads. Incompletely differentiated synapses of both the amacrine and bipolar cell types were often observed, especially in the rat epiretinal transplants. Ganglion cell processes could not be identified with certainty.Although transplant cells were adjacent to host photoreceptor cells and pigment epithelium, obvious specializations or interactions were not observed. The experiments suggest that embryonic rat retinal cell transplants develop most or perhaps all of the structural components and neuronal circuitry necessary to transduce light and process some visual information.

2001 ◽  
Vol 18 (4) ◽  
pp. 559-570 ◽  
Author(s):  
B.E. REESE ◽  
M.A. RAVEN ◽  
K.A. GIANNOTTI ◽  
P.T. JOHNSON

The present study has examined the emergence of cholinergic stratification within the developing inner plexiform layer (IPL), and the effect of ablating the cholinergic amacrine cells on the formation of other stratifications within the IPL. The population of cholinergic amacrine cells in the ferret's retina was identified as early as the day of birth, but their processes did not form discrete strata until the end of the first postnatal week. As development proceeded over the next five postnatal weeks, so the positioning of the cholinergic strata shifted within the IPL toward the outer border, indicative of the greater ingrowth and elaboration of processes within the innermost parts of the IPL. To examine whether these cholinergic strata play an instructive role upon the development of other stratifications which form within the IPL, one-week-old ferrets were treated with l-glutamate in an attempt to ablate the population of cholinergic amacrine cells. Such treatment was shown to be successful, eliminating all of the cholinergic amacrine cells as well as the alpha retinal ganglion cells in the central retina. The remaining ganglion cell classes as well as a few other retinal cell types were partially reduced, while other cell types were not affected, and neither retinal histology nor areal growth was compromised in these ferrets. Despite this early loss of the cholinergic amacrine cells, which are eliminated within 24 h, other stratifications within the IPL formed normally, as they do following early elimination of the entire ganglion cell population. While these cholinergic amacrine cells are present well before other cell types have differentiated, apparently neither they, nor the ganglion cells, play a role in determining the depth of stratification for other retinal cell types.


2010 ◽  
Vol 28 (1) ◽  
pp. 29-37 ◽  
Author(s):  
HANNAH R. JOO ◽  
BETH B. PETERSON ◽  
TONI J. HAUN ◽  
DENNIS M. DACEY

AbstractParallel processing of visual information begins at the first synapse in the retina between the photoreceptors and bipolar cells. Ten bipolar cell types have been previously described in the primate retina: one rod and nine cone bipolar types. In this paper, we describe an 11th type of bipolar cell identified in Golgi-stained macaque retinal whole mount and vertical section. Axonal stratification depth, in addition to dendritic and axonal morphology, distinguished the “giant” cell from all previously well-recognized bipolar cell types. The giant bipolar cell had a very large and sparsely branched dendritic tree and a relatively large axonal arbor that costratified with the DB4 bipolar cell near the center of the inner plexiform layer. The sparseness of the giant bipolar’s dendritic arbor indicates that, like the blue cone bipolar, it does not contact all the cones in its dendritic field. Giant cells contacting the same cones as midget bipolar cells, which are known to contact single long-wavelength (L) or medium-wavelength (M) cones, demonstrate that the giant cell does not exclusively contact short-wavelength (S) cones and, therefore, is not a variant of the previously described blue cone bipolar. This conclusion is further supported by measurement of the cone contact spacing for the giant bipolar. The giant cell contacts an average of about half the cones in its dendritic field (mean ± s.d. = 52 ± 17.6%; n = 6), with a range of 27–82%. The dendrites from single or neighboring giant cells that converge onto the same cones suggest that the giant cell may selectively target a subset of cones with a highly variable local density, such as the L or M cones.


1996 ◽  
Vol 107 (4) ◽  
pp. 535-544 ◽  
Author(s):  
R L Chappell ◽  
F J Rosenstein

Organization of afferent information into parallel ON and OFF pathways is a critical feature of the vertebrate visual system. All afferent visual information in the vertebrate retina reaches the inner plexiform layer (IPL) via bipolar cells. It is at the bipolar cell level that separation of ON and OFF information first appears for afferent information from cones. This may also hold true for the rod pathway of cold-blooded vertebrates, but not for mammals. The all-rod retina of the skate presents an opportunity to examine such pathways in a retina having but a single class of photoreceptor. Immunocytochemical evidence suggests that both ON and OFF bipolar cells are present in the skate retina. We examined the pharmacology of the skate electroretinogram (ERG) to test the hypothesis that independent ON and OFF bipolar cell pathways are functional as rod afferent pathways from outer to inner plexiform layer in the skate. 100 microM 2-amino-4-phosphonobutyric acid (APB) reversibly blocked the skate ERG b-wave. A small d-wave-like OFF component of the ERG revealed by DC recording of response to a prolonged (10 s) flash of light was reduced or blocked by 5 mM kynurenic acid (KYN). We found that addition of 200 microM picrotoxin to the Ringer's solution revealed prominent ON and OFF components of the skate ERG while reducing the c-wave. These ON and OFF components were reversibly blocked by 100 microM APB and 5 mM KYN, respectively. Reversible block of the OFF component by KYN was also accomplished in the presence of 500 microM N-methyl-DL-aspartate. From these findings, we conclude that ON and OFF bipolar cells are likely to be functional as parallel afferent interplexiform pathways in the all-rod retina of the skate.


2003 ◽  
Vol 20 (4) ◽  
pp. 453-463 ◽  
Author(s):  
SCOTT CROUSILLAC ◽  
MICHELLE LEROUGE ◽  
MICHELE RANKIN ◽  
EVANNA GLEASON

In the vertebrate retina, multiple cell types express G protein-coupled receptors linked to the IP3 signaling pathway. The signaling engendered by activation of this pathway can involve activation of calcium permeable transient receptor potential (TRP) channels. To begin to understand the role of these channels in the retina, we undertake an immunocytochemical localization of two TRP channel subunits. Polyclonal antibodies raised against mammalian TRPC1 and TRPC4 are used to localize the expression of these proteins in sections of the adult chicken retina. Western blot analysis indicates that these antibodies recognize avian TRPC1 and TRPC4. TRPC1 labeling is almost completely confined to the inner plexiform layer (IPL) where it labels a subset of processes that ramify in three broad stripes. Occasionally, cell bodies are labeled. These can be found in the inner nuclear layer (INL) proximal to the IPL, the IPL, and the ganglion cell layer (GCL). Double-labeling experiments using a polyclonal antibody that recognizes brain nitric oxide synthase (bNOS) in the chicken indicate that many of the TRPC1-positive processes and cell bodies also express bNOS. Labeling with the TRPC4 antibody was much more widespread with some degree of labeling found in all layers of the retina. TRPC4 immunoreactivity was found in the photoreceptor layer, in the outer plexiform layer (OPL), in radially oriented cells in the INL, diffusely in the IPL, and in vertically oriented elements below the GCL. Double-labeling experiments with a monoclonal antibody raised against vimentin indicate that the TRPC4-positive structures in the INL and below the GCL are Müller cells. Thus, TRPC1 and TRPC4 subunits have unique expression patterns in the adult chicken retina. The distributions of these two subunits indicate that different retinal cell types express TRP channels containing different subunits.


The structure of the human, but mainly of the rhesus monkey, retina as examined by Golgi-staining techniques is described and interpreted on evidence from both light and electron microscopy. One type of rod bipolar cell and two types of cone bipolar cell are recognized. The rod bipolar is exclusively connected to rods. The midget bipolar is postsynaptic to only one cone but each cone is also presynaptic to a diffuse cone (flat) bipolar. Such flat bipolar cells are in synaptic relationship with about seven cones. No other bipolar cell types have been found. The brush bipolar of Polyak is interpreted as probably a distorted rod bipolar, while Polyak’s centrifugal bipolar is a misinterpretation of the morphology of diffuse amacrine cells. When presumptive centrifugal bipolars were observed they appeared to be a developmental stage of amacrine cells. In the outer plexiform layer two types of horizontal cell have been defined. Each type of horizontal cell has a single axon and two kinds of horizontal cell axon terminals are recognized. In the inner plexiform layer there are two main classes of amacrine cells: the stratified amacrines and the diffuse amacrines. Each class of amacrine has a wide variety of shapes. Polyak’s midget ganglion cell is confirmed and his five other kinds of ganglion cell are classified into diffuse and stratified ganglion cells according to the level at which their dendrites branch within the inner plexiform layer. A fuller summary is given by the diagram and in the legend of figure 98, p. 174. A new type of midget bipolar is described in the Appendix (p. 177).


1999 ◽  
Vol 16 (6) ◽  
pp. 1029-1035 ◽  
Author(s):  
STEPHEN L. MILLS

In mammals, gap junctions between retinal bipolar cells are generally small and tracer coupling has not been previously demonstrated. In this study, Neurobiotin was injected into the Ba3-type cone bipolar cell, a medium-field cone bipolar cell that ramifies in sublamina a of the rabbit retina. Tracer spread to many other Ba3 bipolar cells, presumably through gap junctions. It also spread to a smaller field bipolar cell called the Ba1 that ramifies at the same depth of the inner plexiform layer. Injection of Neurobiotin into Ba1 bipolar cells did not produce staining beyond the injected cell. Tracer coupling from the Ba3 was therefore both heterologous, in that different cell types were stained, and asymmetric. The unusual properties of this bipolar cell suggest that its function may differ from that of most cone bipolar cells, which are narrow-field, do not overlap, and are poorly coupled to one another.


2013 ◽  
Vol 521 (5) ◽  
pp. Spc1-Spc1
Author(s):  
J. Scott Lauritzen ◽  
James R. Anderson ◽  
Bryan W. Jones ◽  
Carl B. Watt ◽  
Shoeb Mohammed ◽  
...  

2001 ◽  
Vol 18 (5) ◽  
pp. 695-702 ◽  
Author(s):  
ALLAN F. WIECHMANN ◽  
CELESTE R. WIRSIG-WIECHMANN

In the retina of the African clawed frog (Xenopus laevis), melatonin is synthesized by the photoreceptors at night, and binds to receptors that likely mediate paracrine responses. Melatonin appears to alter the sensitivity of the retinal cells to light, and may play a key role in regulating important circadian events that occur in the eye. A polyclonal antibody was raised against a 13 amino acid peptide corresponding to a region of the third cytoplasmic loop of the Xenopus laevis Mel1c melatonin receptor. Western blot analysis revealed a major immunoreactive band of approximately 60 kD in neural retina and retinal pigment epithelium (RPE) membranes. Immunocytochemical labeling of sections of Xenopus eyes demonstrated intense melatonin receptor-like immunoreactivity in the inner plexiform layer (IPL). Immunolabeling with antibodies to glutamate decarboxylase (GAD) or tyrosine hydroxylase (TOH) appeared to co-localize with the melatonin receptor immunoreactivity in different sublaminas of the IPL. This suggests that both GABAergic and dopaminergic amacrine cells express melatonin receptor protein. There were also some melatonin receptor immunoreactive varicose fibers in the IPL that did not co-localize with either TOH or GAD, and may represent efferent fibers, since they could be followed into the optic nerve. Melatonin receptor immunoreactivity was also present on cell soma in the ganglion cell layer. Furthermore, a moderate level of melatonin receptor immunoreactivity was observed in the RPE and rod and cone photoreceptor cells. The presence of melatonin receptor immunoreactivity in these cells supports previous observations of melatonin receptor RNA expression in multiple cell types in the Xenopus retina. Expression of melatonin receptor protein in the photoreceptors suggests that melatonin may have a direct action on these cells.


1992 ◽  
Vol 9 (3-4) ◽  
pp. 279-290 ◽  
Author(s):  
Dennis M. Dacey ◽  
Sarah Brace

AbstractIntracellular injections of Neurobiotin were used to determine whether the major ganglion cell classes of the macaque monkey retina, the magnocellular-projecting parasol, and the parvocellular-projecting midget cells showed evidence of cellular coupling similar to that recently described for cat retinal ganglion cells. Ganglion cells were labeled with the fluorescent dye acridine orange in an in vitro, isolated retina preparation and were selectively targeted for intracellular injection under direct microscopic control. The macaque midget cells, like the beta cells of the cat's retina, showed no evidence of tracer coupling when injected with Neurobiotin. By contrast, Neurobiotin-filled parasol cells, like cat alpha cells, showed a distinct pattern of tracer coupling to each other (homotypic coupling) and to amacrine cells (heterotypic coupling).In instances of homotypic coupling, the injected parasol cell was surrounded by a regular array of 3–6 neighboring parasol cells. The somata and proximal dendrites of these tracer-coupled cells were lightly labeled and appeared to costratify with the injected cell. Analysis of the nearest-neighbor distances for the parasol cell clusters showed that dendritic-field overlap remained constant as dendritic-field size increased from 100–400 μm in diameter.At least two amacrine cell types showed tracer coupling to parasol cells. One amacrine type had a small soma and thin, sparsely branching dendrites that extended for 1–2 mm in the inner plexiform layer. A second amacrine type had a relatively large soma, thick main dendrites, and distinct, axon-like processes that extended for at least 2–3 mm in the inner plexiform layer. The main dendrites of the large amacrine cells were closely apposed to the dendrites of parasol cells and may be the site of Neurobiotin transfer between the two cell types. We suggest that the tracer coupling between neighboring parasol cells takes place indirectly via the dendrites of the large amacrine cells and provides a mechanism, absent in midget cells, for increasing parasol cell receptive-field size and luminance contrast sensitivity.


1994 ◽  
Vol 11 (4) ◽  
pp. 753-761 ◽  
Author(s):  
Ron P. Gallemore ◽  
Jian-Dong Li ◽  
Victor I. Govardovskii ◽  
Roy H. Steinberg

AbstractWe have studied light-evoked changes in extracellular Ca2+ concentration in the intact cat eye using ion-sensitive double-barreled microelectrodes. Two prominent changes in Ca2+ concentration were observed that differed in retinal location. There was a light-evoked increase in accompanied by brief ON and OFF transients, which was maximal in the inner plexiform layer and was not further studied. There was an unexpected sustained light-evoked decrease in of relatively rapid onset and offset, which was maximal in the distalmost region of the subretinal space (SRS). in the SRS was 1.0 mM higher than in the vitreous humor during dark adaptation and this transretinal gradient disappeared during rod-saturating illumination. After correcting for the light-evoked increase in the volume of the SRS, an increase in the total Ca2+ content of the SRS during illumination was revealed, which presumably represents the Ca2+ released by rods. To explain the light-evoked changes, we used the diffusion model described in the accompanying paper (Li et al., 1994b), with the addition of light-dependent sources of Ca2+ at the retina/retinal pigment epithelium (RPE) border and rod outer segments. We conclude that a drop in around photoreceptors, which persists during illumination and reduces a transretinal Ca2+ gradient, is the combined effect of the light-evoked SRS volume increase, Ca2+ release from photoreceptors, and an unidentified mechanism(s), which is presumably Ca2+ transport by the RPE. The relatively rapid onset and offset of the decrease remains unexplained. These steady-state shifts in should have significant effects on photoreceptor function, especially adaptation.


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