scholarly journals A simulation study on the effect of ionic currents on transmission from cones to retinal OFF type cone bipolar cells

2019 ◽  
Vol 2 (3) ◽  
pp. 14-20
Author(s):  
Akito Ishihara
Keyword(s):  
Mathematical Model ◽  
Visual Information ◽  
Neural Circuit ◽  
Ganglion Cells ◽  
Light Stimulus ◽  
Ionic Currents ◽  
Ionic Channels ◽  
Bipolar Cells ◽  
Glutamate Concentration ◽  
Cone Bipolar Cells

The retinal cone bipolar cells are interneurons which receive inputs from cone photoreceptors and send outputs to retinal ganglion cells. Several subtypes of bipolar cells have been identified by morphology and electrophysiology in the mammalian retina, which convey distinct visual information to higher order neurons in parallel. The neural circuit in the retina not only converts light information to neural . information, but also performs visual information preprocessing that has not yet been fully understood. Recently, it has been revealed that the neural circuits in retinas of higher vertebrates, such as mammals and primates, have various biophysical properties arising from being composed of ionic channels, ionic pumps, and neurotransmitter receptors. Analysis using a mathematical model based on their ionic mechanisms is essential to understand the visual information processing in the retinal neural circuit of the higher vertebrates. The cones and the bipolar cells respond to continuous variation of light with a graded potential, in an analog manner. Especially, glutamate is continuously released from a cone synapse in the dark and is decreased by hyperpolarization of the cone that receives the light stimulus. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate type ionotropic glutamate receptors (iGluRs) of the OFF type bipolar cells (OFF-BCs) exhibit partial or nearly complete desensitization in the sustained presence of glutamate. In the dark, glutamate concentration in the synaptic cleft of the cone pedicle rises to 0.1–0.5 mM.5,6 The baseline glutamate concentration depends on a sustained hyperpolarization of the cone by light. Thus, for understanding the working of the OFF-BCs, it is important to elucidate the mechanisms of synaptic transmission from cones to OFF-BCs via iGluRs, which undergo desensitization in the various background light conditions. Furthermore, there are various kinds of ionic channels in OFF-BCs that mediate membrane potential responses. It is considered that information transmitted from cones to OFF-BCs is modulated by the intrinsic ionic currents. We analyzed how ionic currents of OFF-BCs contribute to the transmission of light responses by developing a mathematical model.

scholarly journals Differential expression of PKCα and -β in the zebrafish retina

2018 ◽  
Author(s):  
Marion F. Haug ◽  
Manuela Berger ◽  
Matthias Gesemann ◽  
Stephan C. F. Neuhauss
Keyword(s):  
Bipolar Cell ◽  
Visual Information ◽  
Neural Circuit ◽  
Ganglion Cells ◽  
Immunohistochemical Analysis ◽  
Cell Types ◽  
Bipolar Cells ◽  
Retinal Ganglion ◽  
Retinal Tissue ◽  
Kinase C

AbstractThe retina is a complex neural circuit in which visual information is transmitted and processed from light perceiving photoreceptors to projecting retinal ganglion cells. Much of the computational power of the retina rests on signal integrating interneurons, such as bipolar cells in the outer retina. While mammals possess about 10 different bipolar cell types, zebrafish (Danio rerio) has at least six ON-type, seven OFF-type, and four mixed-input bipolar cells. Commercially available antibodies against bovine and human conventional protein kinase C (PKC) α and -β are frequently used as markers for retinal ON-bipolar cells in different species, despite the fact that it is not known which bipolar cell subtype(s) they actually label.Moreover, the expression pattern of the five prkc genes (coding for PKC proteins) has not been systematically determined. While prkcg is not expressed in retinal tissue, the other four prkc (prkcaa, prkcab, prkcba, prkcbb) transcripts were found in different parts of the inner nuclear layer and some as well in the retinal ganglion cell layer.Immunohistochemical analysis in adult zebrafish retina using PKCα and PKCβ antibodies showed an overlapping immunolabeling of ON-bipolar cells that are most likely of the BON s6L or RRod type and of the BON s6 type. However, comparison of transcript expression with immunolabling, implies that these antibodies are not specific for one single zebrafish conventional PKC, but rather detect a combination of PKC -α and -β variants.

scholarly journals Differential expression of three T-type calcium channels in retinal bipolar cells in rats

2009 ◽  
Vol 26 (2) ◽  
pp. 177-187 ◽  
Author(s):  
CAIPING HU ◽  
ANDING BI ◽  
ZHUO-HUA PAN
Keyword(s):  
Visual Information ◽  
Ganglion Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Calcium Currents ◽  
Biophysical Properties ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent ◽  
Retinal Bipolar Cells ◽  
Cone Bipolar Cells

AbstractRetinal bipolar cells convey visual information from photoreceptors to retinal third-order neurons, amacrine and ganglion cells, with graded potentials through diversified cell types. To understand the possible role of voltage-dependent T-type Ca2+ currents in retinal bipolar cells, we investigated the pharmacological and biophysical properties of T-type Ca2+ currents in acutely dissociated retinal cone bipolar cells from rats using whole-cell patch-clamp recordings. We observed a broad group of cone bipolar cells with prominent T-type Ca2+ currents (T-rich) and another group with prominent L-type Ca2+ currents (L-rich). Based on the pharmacological and biophysical properties of the T-type Ca2+ currents, T-rich cone bipolar cells could be divided into three subgroups. Each subgroup appeared to express a single dominant T-type Ca2+ channel subunit. The T-type calcium currents could generate low-threshold regenerative potentials or spikes. Our results suggest that T-type Ca2+ channels may play an active and distinct signaling role in second-order neurons of the visual system, in contrast to the common signaling by L-rich bipolar cells.

scholarly journals Dark-adapted response threshold of OFF ganglion cells is not set by OFF bipolar cells in the mouse retina

2012 ◽  
Vol 107 (10) ◽  
pp. 2649-2659 ◽  
Author(s):  
A. Cyrus Arman ◽  
Alapakkam P. Sampath
Keyword(s):  
Ganglion Cells ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Response Threshold ◽  
Mouse Retina ◽  
Signal Flow ◽  
Visual Threshold ◽  
Aii Amacrine Cells ◽  
Aii Amacrine ◽  
Cone Bipolar Cells

The nervous system frequently integrates parallel streams of information to encode a broad range of stimulus strengths. In mammalian retina it is generally believed that signals generated by rod and cone photoreceptors converge onto cone bipolar cells prior to reaching the retinal output, the ganglion cells. Near absolute visual threshold a specialized mammalian retinal circuit, the rod bipolar pathway, pools signals from many rods and converges on depolarizing (AII) amacrine cells. However, whether subsequent signal flow to OFF ganglion cells requires OFF cone bipolar cells near visual threshold remains unclear. Glycinergic synapses between AII amacrine cells and OFF cone bipolar cells are believed to relay subsequently rod-driven signals to OFF ganglion cells. However, AII amacrine cells also make glycinergic synapses directly with OFF ganglion cells. To determine the route for signal flow near visual threshold, we measured the effect of the glycine receptor antagonist strychnine on response threshold in fully dark-adapted retinal cells. As shown previously, we found that response threshold for OFF ganglion cells was elevated by strychnine. Surprisingly, strychnine did not elevate response threshold in any subclass of OFF cone bipolar cell. Instead, in every OFF cone bipolar subclass strychnine suppressed tonic glycinergic inhibition without altering response threshold. Consistent with this lack of influence of strychnine, we found that the dominant input to OFF cone bipolar cells in darkness was excitatory and the response threshold of the excitatory input varied by subclass. Thus, in the dark-adapted mouse retina, the high absolute sensitivity of OFF ganglion cells cannot be explained by signal transmission through OFF cone bipolar cells.

Unique functional properties of the APB sensitive and insensitive rod pathways signaling light decrements in mouse retinal ganglion cells

2006 ◽  
Vol 23 (1) ◽  
pp. 127-135 ◽  
Author(s):  
GUO-YONG WANG
Keyword(s):  
Functional Properties ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Mouse Retina ◽  
Clear Cut ◽  
Types Of Information ◽  
Rod Bipolar Cells ◽  
Rod Pathway ◽  
Cone Bipolar Cells

Light decrements are mediated by two distinct groups of rod pathways in the dark-adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist DL-2-amino-phosphonobutyric (APB). By means of the APB sensitive pathway, rods transmit light decrementsviarod bipolar cells to AII amacrine cells, then to Off cone bipolar cells, which in turn innervate the dendrites of Off ganglion cells. APB hyperpolarizes rod bipolar cells, thus blocking this rod pathway. With APB insensitive pathways, rods either directly synapse onto Off cone bipolar cells, or rods pass light decrement signal to cones by gap junctions. In the present study, whole-cell patch-clamp recordings were made from ganglion cells in the dark-adapted mouse retina to investigate the functional properties of APB sensitive and insensitive rod pathways. The results revealed several clear-cut differences between the APB sensitive and APB insensitive rod pathways. The latency of Off responses to a flashing spot of light was significantly shorter for the APB insensitive pathways than those for the APB sensitive pathway. Moreover, Off responses of the APB insensitive pathways were found to be capable of following substantially higher stimulus frequencies. Nitric oxide was found to selectively block Off responses in the APB sensitive rod pathway. Collectively, these results provide evidence that the APB sensitive and insensitive rod pathways can convey different types of information signaling light decrements in the dark-adapted retina.

scholarly journals Strip1 regulates retinal ganglion cell survival by suppressing Jun-mediated apoptosis to promote retinal neural circuit formation

2021 ◽  
Author(s):  
Mai Ahmed ◽  
Yutaka Kojima ◽  
Ichiro Masai
Keyword(s):  
Molecular Mechanisms ◽  
Neural Circuit ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Bipolar Cells ◽  
Inner Plexiform Layer ◽  
Retinal Ganglion ◽  
Interacting Protein ◽  
Retina Development ◽  
Circuit Formation

In the vertebrate retina, an interplay between retinal ganglion cells (RGCs), amacrine and bipolar cells establishes a synaptic layer called the inner plexiform layer (IPL). This circuit conveys signals from photoreceptors to visual centers in the brain. However, the molecular mechanisms involved in its development remain poorly understood. Striatin-interacting protein 1 (Strip1) is a core component of the STRIPAK complex, and it has shown emerging roles in embryonic morphogenesis. Here, we uncover the importance of Strip1 in inner retina development. Using zebrafish, we show that loss of Strip1 causes defects in IPL formation. In strip1 mutants, RGCs undergo dramatic cell death shortly after birth. Amacrine and bipolar cells subsequently invade the degenerating RGC layer, leading to a disorganized IPL. Thus, Strip1 promotes IPL formation through RGC maintenance. Mechanistically, zebrafish Strip1 interacts with its STRIPAK partner, Striatin3, to promote RGC survival by suppressing Jun-mediated apoptosis. In addition to its function in RGC maintenance, Strip1 is required for RGC dendritic patterning, which likely contributes to proper IPL formation. Taken together, we propose that a series of Strip1-mediated regulatory events coordinates inner retinal circuit formation by maintaining RGCs during development, which ensures proper positioning and neurite patterning of inner retinal neurons.

Distribution of protein kinase C isoforms in the cat retina

2002 ◽  
Vol 19 (5) ◽  
pp. 549-562 ◽  
Author(s):  
BOZENA FYK-KOLODZIEJ ◽  
WENHUI CAI ◽  
ROBERTA G. POURCHO
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Inner Plexiform Layer ◽  
Kinase C ◽  
Cat Retina ◽  
Rod Bipolar Cells ◽  
Cone Bipolar Cells

Immunocytochemical localization was carried out for five isoforms of protein kinase C (PKC) in the cat retina. In common with other mammalian species, PKCα was found in rod bipolar cells. Staining was also seen in a small population of cone bipolar cells with axon terminals ramifying near the middle of the inner plexiform layer (IPL). PKCβI was localized to rod bipolar cells, one class of cone bipolar cell, and numerous amacrine and displaced amacrine cells. Staining for PKCβII was seen in three types of cone bipolar cells as well as in amacrine and ganglion cells. Immunoreactivity for both PKCε and PKCζ was found in rod bipolar cells; PKCε was also seen in a population of cone bipolar cells and a few amacrine and ganglion cells whereas PKCζ was found in all ganglion cells. Double-label immunofluorescence studies showed that dendrites of the two PKCβII-positive OFF-cone bipolar cells exhibit immmunoreactivity for the kainate-selective glutamate receptor GluR5. The third PKCβII cone bipolar is an ON-type cell and did not stain for GluR5. The retinal distribution of these isoforms of PKC is consistent with a role in modulation of various aspects of neurotransmission including synaptic vesicle release and regulation of receptor molecules.

Temporal Contrast Enhancement via GABAC Feedback at Bipolar Terminals in the Tiger Salamander Retina

1998 ◽  
Vol 79 (4) ◽  
pp. 2171-2180 ◽  
Author(s):  
Cun-Jian Dong ◽  
Frank S. Werblin
Keyword(s):  
Receptor Antagonist ◽  
Contrast Enhancement ◽  
Ganglion Cells ◽  
Lucifer Yellow ◽  
Light Stimulus ◽  
Ringer Solution ◽  
Bipolar Cells ◽  
Voltage Response ◽  
Tiger Salamander ◽  
Temporal Contrast

Dong, Cun-Jian and Frank S. Werblin. Temporal contrast enhancement via GABAC feedback at bipolar terminals in the tiger salamander retina. J. Neurophysiol. 79: 2171–2180, 1998. Most retinal amacrine (ACs) and ganglion cells (GCs) express temporal contrast by generating action potentials at only the onset and offset of the light stimulus. This study investigated the neural mechanisms that underlie this temporal contrast enhancement. Whole cell patch recordings were made from bipolar cells (BCs), ACs, and GCs in the retinal slice preparation. The cells were identified by the locations of their somas in the inner nuclear layer and ganglion cell layers, their characteristic light responses, and morphology revealed by Lucifer yellow staining. Depolarizing a single BC with a brief voltage pulse elicited a Cl− tail current that was completely abolished when Ca2+ entry to bipolar terminals was prevented, by either removing Ca2+ from the Ringer solution or blocking Ca2+ channels with Co2+. This suggests that the Cl− current is Ca2+-dependent. In those bipolar cells whose axon terminals were cutoff during slicing no Cl− current was observed, indicating that this current is generated at the synaptic terminals. The Cl− current consists of a predominant synaptic component that can be blocked by the non- N-methyl-d-aspartate (NMDA) glutamate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or by the γ-aminobutyric acid-C (GABAC) receptor antagonist picrotoxin. There also exists a relatively small nonsynaptic component. Thus both glutamatergic and GABAergic transmission were involved in the generation of this Cl− current, suggesting that it is mediated by a recurrent feedback to bipolar cells. Picrotoxin, which blocks both GABAC receptors at BC terminals and GABAA receptors on the dendrites of ACs and GCs, converted the light-elicited voltage response in most on-off ACs and GCs from transient to sustained. Bicuculline, which blocks only the GABAA receptors, did not prolong the transient response in on-off ACs and GCs. This suggests that a negative feedback mediated by the GABAC receptor on the bipolar terminals is responsible for making these responses transient. After the GABAergic feedback was blocked with picrotoxin the light-elicited voltage responses (recorded under current clamp) were more sustained than the current responses (recorded under voltage clamp) to the same light stimuli. This suggests that a voltage-dependent conductance converts the relatively transient current responses to more sustained voltage responses. Our results imply a synaptically driven local GABAergic feedback at bipolar terminals, mediated by GABAC receptors. This feedback appears to be a significant component of the mechanism underlying temporal contrast enhancement in on-off ACs and GCs.

Neurofibrillar bipolar cells in the capybara retina

1996 ◽  
Vol 13 (6) ◽  
pp. 1173-1177 ◽  
Author(s):  
Elizabeth S. Yamada ◽  
Luiz Carlos L. Silveira
Keyword(s):  
Ganglion Cells ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Retinal Cell ◽  
Coverage Factor ◽  
Cone Bipolar Cells

AbstractUsing a reduced-silver neurofibrillar method, we stained a population of bipolar cells in the capybara retina. These cells are distributed throughout the retina following the same topography of other retinal cell classes as the A-type horizontal cells and ganglion cells. The level of axonal stratification, mosaic regularity, and dendritic coverage factor suggest that these neurofibrillar bipolar cells comprise a population of sublamina a cone bipolar cells.

scholarly journals Cell density ratios in a foveal patch in macaque retina

2003 ◽  
Vol 20 (2) ◽  
pp. 189-209 ◽  
Author(s):  
KAREEM M. AHMAD ◽  
KARL KLUG ◽  
STEVE HERR ◽  
PETER STERLING ◽  
STAN SCHEIN
Keyword(s):  
Cell Density ◽  
Bipolar Cell ◽  
Amacrine Cell ◽  
Ganglion Cells ◽  
Horizontal Cell ◽  
Macaque Monkey ◽  
Bipolar Cells ◽  
Thin Sections ◽  
Density Ratios ◽  
Cone Bipolar Cells

We examine the assumptions that the fovea contains equal numbers of inner (invaginating or ON) and outer (flat or OFF) midget bipolar cells and equal numbers of inner and outer diffuse bipolar cells. Based on reconstruction from electron photomicrographs of serial thin sections through the fovea of a macaque monkey, we reject both assumptions. First, every foveal L and M cone is presynaptic to one inner and one outer midget bipolar cell; however, S cones are presynaptic to one outer but no inner midget bipolar cell. Second, we measure the density of all foveal cells in the same patch of fovea, affording accurate cell density ratios. For each foveal cone pedicle, at a density of 26,500 mm−2, there is close to one (0.88) outer diffuse bipolar cell but only 0.40 inner diffuse bipolar cells. This asymmetry may be related to differences in resolution and sensitivity for light increments and decrements. We also find one (1.01) Müller cell, one (1.01) amacrine cell in the inner nuclear layer, and close to one (0.83) horizontal cell for each cone pedicle. In addition, for each S cone, there are two inner S-cone bipolar cells and two small bistratified ganglion cells. In total, there are 3.4 cone bipolar cells per cone but only 2.6 ganglion cells per cone. The latter ratio is enough to accommodate one midget ganglion cell for each midget bipolar cell.

Localization of AMPA-selective glutamate receptor subunits in the cat retina: A light- and electron-microscopic study

1999 ◽  
Vol 16 (1) ◽  
pp. 169-177 ◽  
Author(s):  
PU QIN ◽  
ROBERTA G. POURCHO
Keyword(s):  
Glutamate Receptor ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Morphological Evidence ◽  
Inner Plexiform Layer ◽  
Electron Microscopic ◽  
Cat Retina ◽  
Cone Bipolar Cells

The distribution of AMPA-selective glutamate receptor subunits was studied in the cat retina using antisera against GluR1 and GluR2/3. Both antisera were localized in postsynaptic sites in the outer plexiform layer (OPL) as well as the inner plexiform layer (IPL). Immunoreactivity for GluR1 was seen in a subpopulation of OFF cone bipolar cells and a number of amacrine and ganglion cells. Within the IPL, processes staining for GluR1 received input from OFF and ON cone bipolar cells but not from rod bipolars. Labeling for GluR2/3 was seen in horizontal cells, an occasional cone bipolar cell, and numerous amacrine and ganglion cells. In the IPL, GluR2/3 staining was postsynaptic to cone bipolar cells in both sublaminae. AII amacrine cells which receive rod bipolar input were also labeled for GluR2/3. With both antisera, staining was limited to a single member of the bipolar dyad complex, providing morphological evidence for functional diversity in glutamatergic pathways.

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