Glycine stimulates calcium-independent release of 3H-GABA from isolated retinas of Xenopus laevis

1990 ◽  
Vol 4 (4) ◽  
pp. 337-348 ◽  
Author(s):  
John F. Smiley ◽  
Scott F. Basinger
Keyword(s):  
Xenopus Laevis ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Free Medium ◽  
Ringer’S Solution ◽  
High Concentrations ◽  
Label Density ◽  
Somatostatin 14

AbstractA perfusion system was used to monitor the release of [3H]-GABA from isolated retinas of Xenopus laevis. Measurable release was stimulated by glycine at concentrations as low as 200 μM. Glycine-stimulated release was blocked by strychnine, and was not reduced in “calcium-free” Ringer's solution (0 Ca2+/20 mM Mg2+). Glutamate also stimulated calcium-independent release, using concentrations as low as 100 μM. In contrast, release stimulated by 25 mM potassium was reduced by 80% in calcium-free medium.In most experiments, agonists were applied in six consecutive 4-mm pulses separated by 10-mm washes with Ringer's solution. Under these conditions, the release stimulated by 0.5 mM glutamate or 25 mM potassium decreased by at least 50% from the first to the second pulse, and then gradually decreased with successive applications. In contrast, the response to 0.5 mM glycine at first increased and then only gradually decreased with successive pulses. These patterns of response to different agonists were similar in calcium-free medium.Somatostatin (—14 or —28) also stimulated release, and this effect was inhibited by AOAA, an inhibitor of GABA degradation. In the presence of AOAA, somatostatin had little effect, except at high concentrations of somatostatin (5 μM), which increased both basal and glycine-stimulated release. In contrast to somatostatin, glycine-stimulated release was much larger in the presence of AOAA.Autoradiography was used to investigate which cell types released [3H]-GABA under our conditions. Autoradiograms showed that horizontal cells and a population of apparent “off” bipolar cells were well-labeled by [3H]-GABA high-affinity uptake. In addition, light labeling was seen over numerous amacrine cells. After application of glycine, glutamate, or potassium, there was a decrease in label density over horizontal cells.

Morphological and functional identifications of catfish retinal neurons. I. Classical morphology

1975 ◽  
Vol 38 (1) ◽  
pp. 53-71 ◽  
Author(s):  
K. Naka ◽  
N. R. Garraway
Keyword(s):  
Ganglion Cells ◽  
Horizontal Cell ◽  
Dendritic Tree ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Inner Nuclear Layer ◽  
Horizontal Cells ◽  
Specific Cell ◽  
Definition Of

The morphology of the catfish horizontal cells is comparable to that in other fish retinas. The external horizontal cells contact cone receptors and are stellate in shape; the intermediate horizontal cells are even more so and contact rod receptors. The internal horizontal cells constitute the most proximal layer of the inner nuclear layer and may possibly be, in reality, extended processes from the other two horizontal cell types. Bipolar cells resemble those in other teleost retinas: the size and shape of their dendritic tree encompass a continuous spectrum ranging from what is known as the small to the large bipolar cells. The accepted definition of amacrine cells is sufficiently vague to justify our originating a more descriptive and less inferential name for the (axonless) neurons in the inner nuclear layer which radiate processes throughout the inner synaptic layer. These starbust and spaghetti cells vary considerably in the character and extent of their dendritic spread, but correlates exist in other vertebrate retinas. Ganglion cells are found not only in the classical ganglion layer but displaced into the inner nuclear layer as well. Several types can be distinguished on the basis of cell geometry and by the properties of their dendritic tree. Not all of the categorization corresponds with previous descriptions; our findings suggest that some reorganization may be necessary in the accepted classification of cells in the proximal areas of the vertebrate retina. A subtle yet remarkable pattern underlies the entire structure of the catfish retina; there exists a definite gradient of size within a particular class of cells, and of configuration among the subclasses of a specific cell type. It remains to be seen if these morphological spectra bear any functional consequences. The fact that the structure of the catfish retina most closely resembles those of other phylogenetically ancient animals, such as the skate and the dogfish shark, testifies to its primitive organization; morphological and functional mechanisms discernible in this simple system may, therefore, be applicable to the retinas of higher ordered vertebrates.

AMPA-selective glutamate receptor subunits GluR2 and GluR4 in the cat retina: An immunocytochemical study

1999 ◽  
Vol 16 (6) ◽  
pp. 1105-1114 ◽  
Author(s):  
PU QIN ◽  
ROBERTA G. POURCHO
Keyword(s):  
Ganglion Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Cat Retina ◽  
Aii Amacrine Cells ◽  
Aii Amacrine

AMPA-selective glutamate receptors play a major role in glutamatergic neurotransmission in the retina and are expressed in a variety of neuronal subpopulations. In the present study, immunocytochemical techniques were used to visualize the distribution of GluR2 and GluR4 subunits in the cat retina. Results were compared with previous localizations of GluR1 and GluR2/3. Staining for GluR2 was limited to a small number of amacrine and ganglion cells whereas GluR4 staining was present in A-type horizontal cells, many amacrine cells including type AII amacrine cells, and the majority of the cells in the ganglion cell layer. Analysis of synaptic relationships in the outer plexiform layer showed the GluR4 subunit to be concentrated at the contacts of cone photoreceptors with A-horizontal cells. In the inner plexiform layer, both GluR2 and GluR4 were postsynaptic to cone bipolar cells at dyad contacts although GluR2 staining was limited to one of the postsynaptic elements whereas GluR4 immunoreactivity was often seen in both postsynaptic elements. Unlike GluR2, GluR4 was also postsynaptic to rod bipolar cells where it could be visualized in processes of AII amacrine cells. The data indicate that GluR3 and GluR4 subunits are colocalized in a number of cell types including A-type horizontal cells, AII amacrine cells, and alpha ganglion cells, but whether they are combined in the same multimeric receptors remains to be determined.

scholarly journals Random spatial patterning of cone bipolar cell mosaics in the mouse retina

2017 ◽  
Vol 34 ◽  
Author(s):  
PATRICK W. KEELEY ◽  
JASON J. KIM ◽  
SAMMY C.S. LEE ◽  
SILKE HAVERKAMP ◽  
BENJAMIN E. REESE
Keyword(s):  
Bipolar Cell ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Statistical Properties ◽  
Horizontal Cells ◽  
Mouse Retina ◽  
Dendritic Arbors ◽  
Cone Bipolar Cells ◽  
Cholinergic Amacrine Cells

AbstractRetinal bipolar cells spread their dendritic arbors to tile the retinal surface, extending them to the tips of the dendritic fields of their homotypic neighbors, minimizing dendritic overlap. Such uniform nonredundant dendritic coverage of these populations would suggest a degree of spatial order in the properties of their somal distributions, yet few studies have examined the patterning in retinal bipolar cell mosaics. The present study examined the organization of two types of cone bipolar cells in the mouse retina, the Type 2 cells and the Type 4 cells, and compared their spatial statistical properties with those of the horizontal cells and the cholinergic amacrine cells, as well as to random simulations of cells matched in density and constrained by soma size. The Delauney tessellation of each field was computed, from which nearest neighbor distances and Voronoi domain areas were extracted, permitting a calculation of their respective regularity indexes (RIs). The spatial autocorrelation of the field was also computed, from which the effective radius and packing factor (PF) were determined. Both cone bipolar cell types were found to be less regular and less efficiently packed than either the horizontal cells or cholinergic amacrine cells. Furthermore, while the latter two cell types had RIs and PFs in excess of those for their matched random simulations, the two types of cone bipolar cells had spatial statistical properties comparable to random distributions. An analysis of single labeled cone bipolar cells revealed dendritic arbors frequently skewed to one side of the soma, as would be expected from a randomly distributed population of cells with dendrites that tile. Taken together, these results suggest that, unlike the horizontal cells or cholinergic amacrine cells which minimize proximity to one another, cone bipolar cell types are constrained only by their physical size.

Taurine and GABA in the rat retina during postnatal development

1994 ◽  
Vol 11 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Norma Lake
Keyword(s):  
Postnatal Development ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Fiber Layer ◽  
Rat Retina

AbstractThe content of taurine and the immunocytochemical localization of taurine and γ-aminobutyric acid (GABA) in the rat retina during postnatal development are described. The rat retina is immature at birth; about two-thirds of the cells are undifferentiated neuroblasts, and the taurine content per retina is approximately one-seventh of the adult value. Shortly after weaning the adult morphology and taurine content are attained. Expression of taurine immunoreactivity (taurine-IR) accompanies differentiation; in some cell types (ganglion and horizontal cells) this expression is transient, while in others (photoreceptors, bipolar, and a subpopulation of amacrine cells) it persists into the adult state. At birth, taurine-IR is localized mainly in cells in the position of ganglion cells, especially in their axons within the nerve fiber layer. This reactivity is soon lost from the somata, and disappears from the axons by 10 days of age. At 2 days of age, taurine-IR appeared additionally in somata of amacrine cells flanking the forerunner of the inner plexiform layer, and in growth cone-like processes of photoreceptors. At day 6, taurine-IR was marked in photoreceptor cell inner and outer segments, and in horizontal cells and their lateral processes. Taurine-IR was lost from horizontal cells and most amacrine cells around day 10, and appeared in bipolar cells, where it remained, with that in photoreceptors, into adulthood. Particularly striking was taurine-IR in large synaptic terminal-like processes close to the ganglion cell layer which were first seen around day 16. GABA immunoreactivity was never seen in photoreceptor or bipolar cells, was expressed transiently in horizontal cells at the same time as taurine-IR, but persisted in a subpopulation of amacrine cells and synaptic lamina in the inner plexiform layer and in some fine glial processes in the adult.

Differential expression of glutamate receptor genes (GluR1-5) in the rat retina

1992 ◽  
Vol 8 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Thomas E. Hughes ◽  
Irm Hermans-Borgmeyer ◽  
Steve Heinemann
Keyword(s):  
Glutamate Receptor ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Inner Nuclear Layer ◽  
Dissociated Cells ◽  
Different Cell Types ◽  
The Brain ◽  
Overlapping Sets

AbstractThe recent isolation of at least five different cDNAs encoding functional subunits of glutamate receptors (GluR1 to GluR5) has revealed a diversity whose function is not understood. To learn more about how these different receptor subunits are used in the brain, we undertook an in situ hybridization study of the retina to define how the different glutamate receptor genes are expressed. We chose the retina because the glutamate sensitivities of its different cell types have been characterized, and these different neurons reside in different laminae.Hybridization of [35S]UTP-labeled cRNA probes with transverse sections and freshly dissociated cells reveals that all five receptor subunits are expressed in the retina. Hybridization signal is detected in different, but overlapping, sets of cells in the retina. GluR1, GluR2, and GluR5 are expressed by many somata, and GluR4 by a few, in the outer third of the inner nuclear layer, where the horizontal cells reside. Transcripts for GluR1, GluR2, and GluR5 are found in the somata within the middle third of the inner nuclear layer, which is where the bipolar cell somata are located, and GluR2 probes label freshly dissociated rod bipolar cells. All of the probes produce labeling over the cells at the inner edge of the inner nuclear layer, which are probably amacrine cells, as well as over the cell bodies in the ganglion cell layer.

Glutamate-, GABA-, and GAD-immunoreactivities co-localize in bipolar cells of tiger salamander retina

1994 ◽  
Vol 11 (6) ◽  
pp. 1193-1203 ◽  
Author(s):  
Chen-Yu Yang ◽  
Stephen Yazulla
Keyword(s):  
Ganglion Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Inner Nuclear Layer ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Cell Responses ◽  
Immunocytochemical Method ◽  
Separate Population

AbstractThe presence of inhibitory bipolar cells in salamander retina was investigated by a comparative analysis of the distribution of glutamate- and GABA-immunoreactivities (GLU-IR; GABA-IR) using a postembedding immunocytochemical method. GLU-IR was found in virtually all photoreceptors, bipolar cells and ganglion cells, neuronal elements that transfer information vertically through the retina. GLU-IR also was found in numerous amacrine cells in the mid and proximal inner nuclear layer as well as in the cytoplasm of horizontal cells, while the nucleus of horizontal cells was either lightly labeled or not labeled at all. GLU-IR was found in the outer plexiform layer and intensely in the inner plexiform layer, in which there was no apparent sublamination. Forty-seven percent of Type IB bipolar cells in the distal inner nuclear layer and 13% of the displaced bipolar cells were GABA-IR. All bipolar cells were also GLU-IR, indicating that GABA-IR bipolar cells were a subset of GLU-IR bipolar cells rather than a separate population. About 12% of the Type IB bipolar cells were moderately GABA-IR and likely comprised a GABAergic subtype. GLU-IR levels in the presumed GABAergic bipolar cells were higher than in other purely GLU-IR bipolar cells suggesting that these GABA-IR bipolar cells are glutamatergic as well. All of the displaced bipolar cells were only lightly GABA-IR, indicating that displaced bipolar cells comprise a more homogeneous class of glutamatergic cell than orthotopic bipolar cells. GAD-IR co-localized with GABA-IR in orthotopic but not displaced bipolar cells, further supporting the idea that some orthotopic bipolar cells are GABAergic. A small proportion of bipolar cells in salamander retina contain relatively high levels of both GABA and glutamate. Co-release of these substances by bipolar cells could contribute to the “push-pull” modulation of ganglion cell responses.

Serotonin synthesis and accumulation by neurons of the anuran retina

1992 ◽  
Vol 9 (3-4) ◽  
pp. 377-388 ◽  
Author(s):  
Baosong Zhu ◽  
Robert Gábriel ◽  
Charles Straznicky
Keyword(s):  
Culture Medium ◽  
Photoreceptor Cell ◽  
Phenylalanine Hydroxylase ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Ambient Light ◽  
Outer Segments ◽  
Large Numbers ◽  
Two Populations

AbstractSerotonin-synthesizing and serotonin-accumulating neurons were studied in the retinas of Xenopus laevis and Bufo marinus. All previously identified cell types exhibiting serotonin-like immunoreactivity (SLI) were labeled by intravitreal injection of 5,7-dihydroxytryptamine (5,7-DHT). They included two amacrine cell types (large and small) in both species, and one bipolar cell type in Xenopus. Incubation of retinas in culture medium in the ambient light reduced SLI in amacrine cells and enhanced the labeling in bipolar cells. After incubation, some photoreceptor cell bodies and large numbers of outer segments also displayed SLI in both species. Incubation with the serotonin-uptake inhibitor, fluoxetine, reduced immunolabeling in bipolar cells and outer segments to the level in the untreated retinas.Both large SLI and 5,7-DHT-accumulating amacrine cells in Xenopus and Bufo were labeled with an antibody raised against phenylalanine hydroxylase (PH), which binds to tryptophan 5-hydroxylase, one of the synthesizing enzymes for serotonin. Small SLI and 5,7-DHT-accumulating amacrine cells in both species represented two populations, one with and the other without PH-like immunoreactivity (PH-LI). The anti-PH antibody failed to label any SLI or 5,7-DHT-accumulating bipolar cells in Xenopus.These observations indicate that all large and some small SLI amacrine cells in the retinas of Xenopus and Bufo synthesize serotonin, while other small SLI amacrine, bipolar and photoreceptor cell bodies, and outer segments only accumulate serotonin.

Similarities and differences among inner retinal neurons revealed by the expression of reporter transgenes controlled by Brn-3a, Brn-3b, and Brn-3c promotor sequences

1996 ◽  
Vol 13 (5) ◽  
pp. 955-962 ◽  
Author(s):  
Mengqing Xiang ◽  
Lijuan Zhou ◽  
Jeremy Nathans
Keyword(s):  
Ganglion Cells ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Placental Alkaline Phosphatase ◽  
Retinal Neurons ◽  
Transcriptional Regulatory ◽  
Human Placental Alkaline Phosphatase ◽  
Transgenic Lines ◽  
Multiple Cell

AbstractBrn-3a, Brn-3b, and Brn-3c are highly homologous POU-domain transcription factors that are expressed in subsets of retinal ganglion cells. From each of the mouse Brn-3 genes, a DNA segment ranging in size from 4.6 to 13.4 kb and located immediately upstream of the start site of translation was joined to a human placental alkaline phosphatase (AP) reporter cDNA. Following the introduction of each construct into the mouse germline, a total of 19 transgenic lines were obtained, of which 16 expressed the AP reporter in the retina. Unexpectedly, at least 14 of the 16 expressing lines showed AP activity in subsets of amacrine cells, and these subsets typically differed among mouse lines injected with the same construct. Transgene expression was also found in ganglion cells in four lines and bipolar cells in seven lines. In all cases AP activity was confined to cells in the inner nuclear layer and the ganglion cell layer. The expression of Brn-3 transgenes in multiple cell types in the inner retina is reminiscent of earlier experiments in which visual pigment transgenes were found to be expressed in multiple cell types in the outer retina. Taken together, these observations suggest that anatomically and/or functionally related retinal neurons contain partially overlapping transcriptional regulatory specificities.

scholarly journals Removal of extracellular chloride suppresses transmitter release from photoreceptor terminals in the mudpuppy retina.

1996 ◽  
Vol 107 (5) ◽  
pp. 631-642 ◽  
Author(s):  
W B Thoreson ◽  
R F Miller
Keyword(s):  
Glutamate Release ◽  
Outward Current ◽  
Cell Voltage ◽  
Input Resistance ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Free Medium ◽  
Necturus Maculosus ◽  
Inward Currents ◽  
Cl Channels

Removal of extracellular Cl- has been shown to suppress light-evoked voltage responses of ON bipolar and horizontal cells, but not photoreceptors or OFF bipolar cells, in the amphibian retina. A substantial amount of experimental evidence has demonstrated that the photoreceptor transmitter, L-glutamate, activates cation, not Cl-, channels in these cells. The mechanism for Cl-free effects was therefore reexamined in a superfused retinal slice preparation from the mudpuppy (Necturus maculosus) using whole-cell voltage and current clamp techniques. In a Cl-free medium, light-evoked currents were maintained in rod and cone photoreceptors but suppressed in horizontal, ON bipolar, and OFF bipolar cells. Changes in input resistance and dark current in bipolar and horizontal cells were consistent with the hypothesis that removal of Cl- suppresses tonic glutamate release from photoreceptors. The persistence of light-evoked voltage responses in OFF bipolar cells, despite the suppression of light-evoked currents, is due to a compensatory increase in input resistance. Focal application of hyperosmotic sucrose to photoreceptor terminals produced currents in bipolar and horizontal cells arising from two sources: (a) evoked glutamate release and (b) direct actions of the hyperosmotic solution on postsynaptic neurons. The inward currents resulting from osmotically evoked release of glutamate in OFF bipolar and horizontal cells were suppressed in a Cl-free medium. For ON bipolar cells, both the direct and evoked components of the hyperosmotic response resulted in outward currents and were thus difficult to separate. However, in some cells, removal of extracellular Cl- suppressed the outward current consistent with a suppression of presynaptic glutamate release. The results of this study suggest that removal of extracellular Cl- suppresses glutamate release from photoreceptor terminals. Thus, it is possible that control of [Cl-] in and around photoreceptors may regulate glutamate release from these cells.

The interplexiform cell system II. Effects of dopamine on goldfish retinal neurones

1978 ◽  
Vol 201 (1142) ◽  
pp. 27-55 ◽  
Keyword(s):  
Horizontal Cell ◽  
Cell Activity ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell System ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Specific Effects ◽  
Β Blocker

The effects of atomized solutions of dopamine and certain related com­pounds have been tested on the intracellularly recorded activity of receptor, horizontal, bipolar and amacrine cells in the goldfish retina. Dopamine depolarizes the cone L-type horizontal cells and reduces the amplitude of light-evoked responses. These effects on L-type horizontal cells are completely abolished by the α-adrenergie blocker, phentolamine, but only partially depressed by the β-blocker, propanolol. L-Dopa, noradrenalin, and serotonin do not have effects on L-type horizontal cells when applied at concentrations similar to those that cause maximal dopamine effects. The results suggest that the effects of dopamine on L-type horizontal cells are specific, and we propose that they mimic the effects of interplexiform cell activity. Dopamine has no effects on rod horizontal cells in goldfish and variable effects on C-type horizontal cells. On bipolar cells, dopamine alters the dark membrane potential, enhances the central response to light, and depresses the surround response. Dopamine also decreases the horizontal cell feedback evident in cone responses. Finally, dopamine strongly depolarizes the transient type of amacrine cells, but it has no significant effect on the sustained type of amacrine cells. Assuming that dopamine is the transmitter of interplexiform cells, we suggest that these neurons regulate lateral inhibitory effects mediated by L-type horizontal cells in the outer plexiform layer and transient amacrine cells in the inner plexiform layer. In addition, it appears as if interplexiform cells have specific effects on bipolar cells and are capable of regulating centre-surround antagonism in these cells. The net effect of interplexiform cell activity is to isolate the bipolars from the influence of the surround.

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