Retinal bipolar cells receive negative feedback input from GABAergic amacrine cells

1988 ◽  
Vol 1 (3) ◽  
pp. 297-305 ◽  
Author(s):  
Masao Tachibana ◽  
Akimichi Kaneko

AbstractBipolar cells make reciprocal synapses with amacrine cells in the inner plexiform layer; both feedforward connections and feedback connections are present. The physiological properties of the feedback synapse have not been well described. Since some amacrine cells are thought to be GABAergic, we examined bipolar cells for feedback input from γ-aminobtyric acid (GABA)ergic amacrine cells. Solitary bipolar cells were dissociated enzymatically from the goldfish retina. Cells were voltage clamped with a patch pipette and their GABA sensitivity was examined. GABA evoked responses in all bipolar cells with a large axon terminal, which were identified to be the rod dominant ON type, and in some bipolar cells with a small axon terminal. The highest GABA sensitivity was located at the axon terminal. The least effective dose was as low as 100 nM. A small insignificant response of high threshold was evoked when GABA was applied to the dendrite and soma. GABA increased the Cl conductance and caused membrane hyperpolarization. The bipolar cells had the GABAA receptor coupled with a benzodiazepine receptor. The GABA-evoked response was not susceptible to Co ions, which suppressed the GABA-induced responses in turtle cones by 50% at 5 fiM concentration. Incomplete desensitization was observed, suggesting that the GABAergic pathway seems capable of transmitting signals tonically. The present results strongly indicate that the rod-dominant ON-type bipolar cells and some bipolar cells with a small axon terminal receive negative feedback inputs from GABAergic amacrine cells.

1996 ◽  
Vol 76 (1) ◽  
pp. 401-422 ◽  
Author(s):  
E. Hartveit

1. With the use of the whole cell voltage-clamp technique, I have recorded the current responses to ionotropic glutamate receptor agonists of rod bipolar cells in vertical slices of rat retina. Rod bipolar cells constitute a single population of cells and were visualized by infrared differential interference contrast video microscopy. They were targeted by the position of their cell bodies in the inner nuclear layer and, after recording, were visualized in their entirety by labeling with the fluorescent dye Lucifer yellow, which was included in the recording pipette. To study current-voltage relationships of evoked currents, voltage-gated potassium currents were blocked by including Cs+ and tetraethylammonium+ in the recording pipette. 2. Pressure application of the non-N-methyl-D-aspartate (non-NMDA) receptor agonists kainate and (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) from puffer pipettes evoked a long-latency conductance increase selective for chloride ions. When the intracellular chloride concentration was increased, the reversal potential changed, corresponding to the change in equilibrium potential for chloride. The response was evoked in the presence of 5 mM Co2+ and nominally O mM Ca2+ in the extracellular solution, presumably blocking all external Ca2(+)-dependent release of neurotransmitter. 3. The long latency of kainate-evoked currents in bipolar cells contrasted with the short-latency currents evoked by gamma-aminobutyric acid (GABA) and glycine in rod bipolar cells and by kainate in amacrine cells. 4. Application of NMDA evoked no response in rod bipolar cells. 5. Coapplication of AMPA with cyclothiazide, a blocker of agonist-evoked desensitization of AMPA receptors, enhanced the conductance increase compared with application of AMPA alone. Coapplication of the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione blocked the response to kainate and AMPA, indicating that the response was mediated by conventional ionotropic glutamate receptors. 6. The conductance increase evoked by non-NMDA receptor agonists could not be blocked by a combination of 100 microM picrotoxin and 10 microM strychnine. Application of the GABAC receptor antagonist 3-aminopropyl (methyl)phosphinic acid (3-APMPA) strongly reduced the response, and coapplication of 500 microM 3-APMPA and 100 microM picrotoxin completely blocked the response. These results suggested that the conductance increase evoked by non-NMDA receptor agonists was mediated by release of GABA and activation of GABAC receptors, and most likely also GABAA receptors, on rod bipolar cells. 7. Kainate responses like those described above could not be evoked in bipolar cells in which the axon had been cut somewhere along its passage to the inner plexiform layer during the slicing procedure. This suggests that the response was dependent on the integrity of the axon terminal in the inner plexiform layer, known to receive GABAergic synaptic input from amacrine cells. 8. The results indicate that ionotropic glutamate receptors are not involved in mediating synaptic input from photoreceptors to rod bipolar cells and that an unconventional mechanism of GABA release from amacrine cells might operate in the inner plexiform layer.


1996 ◽  
Vol 13 (6) ◽  
pp. 1099-1107 ◽  
Author(s):  
Péter Buzás ◽  
Sára Jeges ◽  
Robert Gábriel

AbstractThe main route of information flow through the vertebrate retina is from the photoreceptors towards the ganglion cells whose axons form the optic nerve. Bipolar cells of the frog have been so far reported to contact mostly amacrine cells and the majority of input to ganglion cells comes from the amacrines. In this study, ganglion cells of frogs from two species (Bufo marinus, Xenopus laevis) were filled retrogradely with horseradish peroxidase. After visualization of the tracer, light-microscopic cross sections showed massive labeling of the somata in the ganglion cell layer as well as their dendrites in the inner plexiform layer. In cross sections, bipolar output and ganglion cell input synapses were counted in the electron microscope. Each synapse was assigned to one of the five equal sublayers (SLs) of the inner plexiform layer. In both species, bipolar cells were most often seen to form their characteristic synaptic dyads with two amacrine cells. In some cases, however, the dyads were directed to one amacrine and one ganglion cell dendrite. This type of synapse was unevenly distributed within the inner plexiform layer with the highest occurrence in SL2 both in Bufo and Xenopus. In addition, SL4 contained also a high number of this type of synapse in Xenopus. In both species, we found no or few bipolar to ganglion cell synapses in the marginal sublayers (SLs 1 and 5). In Xenopus, 22% of the bipolar cell output synapses went onto ganglion cells, whereas in Bufo this was only 10%. We conclude that direct bipolar to ganglion cell information transfer exists also in frogs although its occurrence is not as obvious and regular as in mammals. The characteristic distribution of these synapses, however, suggests that specific type of the bipolar and ganglion cells participate in this process. These contacts may play a role in the formation of simple ganglion cell receptive fields.


1991 ◽  
Vol 7 (6) ◽  
pp. 611-618 ◽  
Author(s):  
Roberta G. Pourcho ◽  
Michael T. Owczarzak

AbstractImmunocytochemical techniques were used to localize strychnine-sensitive glycine receptors in cat retina. Light microscopy showed staining in processes ramifying throughout the inner plexiform layer and in cell bodies of both amacrine and ganglion cells. At the electron-microscopic level, receptor immunoreactivity was seen to be clustered at sites postsynaptic to amacrine cells. In contrast, bipolar cells were neither presynaptic nor postsynaptic elements at sites of glycine receptor staining. Double-label studies verified the presence of glycine immunoreactivity in amacrine terminals presynaptic to glycine receptors. These findings support a role for glycine as an inhibitory neurotransmitter in amacrine cells.


1990 ◽  
Vol 5 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Heather M. Young ◽  
David I. Vaney

AbstractThis study has shown that the retinae of Prototherian (egg-laying) mammals possess two neuronal types that are present in non-mammalian retinae, but absent or morphologically different in the retinae of Eutherian (placental) mammals. First, endogenous serotonin-like immunoreactivity has been localized in a population of presumptive amacrine cells in the platypus retina, the first such report in a mammalian retina. Second, the protein kinase C-immunoreactive (PKC-IR) bipolar cells in the echidna retina appear similar to the PKC-IR bipolars in the chicken retina, in that their dendrites give rise to a Landolt's club and their axons are multistratified. By contrast, the PKC-IR rod bipolar cells in the rabbit and in the brushtail possum, a Metatherian (marsupial) mammal, have no Landolt's clubs and their axons form terminal lobes in the innermost stratum of the inner plexiform layer.


2018 ◽  
Author(s):  
Robert E. Marc ◽  
Crystal Sigulinsky ◽  
Rebecca L. Pfeiffer ◽  
Daniel Emrich ◽  
James R. Anderson ◽  
...  

AbstractAll superclasses of retinal neurons display some form of electrical coupling including the key neurons of the inner plexiform layer: bipolar cells (BCs), amacrine or axonal cells (ACs) and ganglion cells (GCs). However, coupling varies extensively by class. For example, mammalian rod bipolar cells form no gap junctions at all, while all cone bipolar cells form class-specific coupling arrays, many of them homocellular in-superclass arrays. Ganglion cells are unique in that classes with coupling predominantly form heterocellular cross-class arrays of ganglion cell::amacrine cell (GC::AC) coupling in the mammalian retina. Ganglion cells are the least frequent superclass in the inner plexiform layer and GC::AC gap junctions are sparsely arrayed amidst massive cohorts of AC::AC, bipolar cell BC::BC, and AC::BC gap junctions. Many of these gap junctions and most ganglion cell gap junctions are suboptical, complicating analysis of specific ganglion cells. High resolution 2 nm TEM analysis of rabbit retinal connectome RC1 allows quantitative GC::AC coupling maps of identified ganglion cells. Ganglion cells classes apparently avoid direct cross-class homocellular coupling altogether even though they have opportunities via direct membrane touches, while transient OFF alpha ganglion cells and transient ON directionally selective (DS) ganglion cells are strongly coupled to distinct amacrine / axonal cell cohorts.A key feature of coupled ganglion cells is intercellular metabolite flux. Most GC::AC coupling involves GABAergic cells (γ+ amacrine cells), which results in significant GABA flux into ganglion cells. Surveying GABA coupling signatures in the ganglion cell layer across species suggests that the majority of vertebrate retinas engage in GC::AC coupling.Multi-hop synaptic queries of the entire RC1 connectome clearly profiles the coupled amacrine and axonal cells. Photic drive polarities and source bipolar cell class selec-tivities are tightly matched across coupled cells. OFF alpha ganglion cells are coupled to OFF γ+ amacrine cells and transient ON DS ganglion cells are coupled to ON γ+ amacrine cells including a large interstitial axonal cell (IAC). Synaptic tabulations show close matches between the classes of bipolar cells sampled by the coupled amacrine and ganglion cells. Further, both ON and OFF coupling ganglion networks show a common theme: synaptic asymmetry whereby the coupled γ+ neurons are also presynaptic to ganglion cell dendrites from different classes of ganglion cells outside the coupled set. In effect, these heterocellular coupling patterns enable an excited ganglion cell to directly inhibit nearby ganglion cells of different classes. Similarly, coupled γ+ amacrine cells engaged in feedback networks can leverage the additional gain of bipolar cell synapses in shaping the signaling of a spectrum of downstream targets based on their own selective coupling with ganglion cells.


1994 ◽  
Vol 11 (6) ◽  
pp. 1193-1203 ◽  
Author(s):  
Chen-Yu Yang ◽  
Stephen Yazulla

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.


2004 ◽  
Vol 21 (4) ◽  
pp. 587-597 ◽  
Author(s):  
MICHAEL KALLONIATIS ◽  
DANIEL SUN ◽  
LISA FOSTER ◽  
SILKE HAVERKAMP ◽  
HEINZ WÄSSLE

Glutamate is a major neurotransmitter in the retina and other parts of the central nervous system, exerting its influence through ionotropic and metabotropic receptors. One ionotropic receptor, the N-methyl-D-aspartate (NMDA) receptor, is central to neural shaping, but also plays a major role during neuronal development and in disease processes. We studied the distribution pattern of different subunits of the NMDA receptor within the rat retina including quantifying the pattern of labelling for all the NR1 splice variants, the NR2A and NR2B subunits. The labelling pattern for the subunits was confined predominantly in the outer two-thirds of the inner plexiform layer. We also wanted to probe NMDA receptor function using an organic cation, agmatine (AGB); a marker for cation channel activity. Although there was an NMDA concentration-dependent increase in AGB labelling of amacrine cells and ganglion cells, we found no evidence of functional NMDA receptors on horizontal cells in the peripheral rabbit retina, nor in the visual streak where the type A horizontal cell was identified by GABA labelling. Basal AGB labelling within depolarizing bipolar cells was also noted. This basal bipolar cell AGB labelling was not modulated by NMDA and was completely abolished by the use of L-2-amino-4-phosphono-butyric acid, which is known to hyperpolarize retinal depolarizing bipolar cells. AGB is therefore not only useful as a probe of ligand-gated drive, but can also identify neurons that have constitutively open cationic channels. In combination, the NMDA receptor subunit distribution pattern and the AGB gating experiments strongly suggests that this ionotropic glutamate receptor is functional in the cone-driven pathway of the inner retina.


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.


1995 ◽  
Vol 12 (2) ◽  
pp. 345-358 ◽  
Author(s):  
J.H. Brandstätter ◽  
U. Greferath ◽  
T. Euler ◽  
H. Wässle

AbstractDirection-selective (DS) ganglion cells of the mammalian retina have their dendrites in the inner plexiform layer (IPL) confined to two narrow strata. The same strata are also occupied by the dendrites of cholinergic amacrine cells which are probably presynaptic to the DS ganglion cells. GABA is known to play a crucial role in creating DS responses. We examined the types of GABAA receptors expressed by the cholinergic amacrine cells and also those expressed by their presynaptic and postsynaptic neurons, by applying immunocytochemical markers to vertical sections of rat retinas. Double-labelling experiments with antibodies against choline acetyltransferase (ChAT) and specific antibodies against different GABAA receptor subunits were performed. Cholinergic amacrine cells seem to express an unusual combination of GABAA receptor subunits consisting of α2-, β1-, β2/3-, γ2-, and δ-subunits. Bipolar cells, which could provide synaptic input to the DS circuitry, were stained with antibodies against the glutamate transporter GLT-1. The axon terminals of these bipolar cells are narrowly stratified in close proximity to the dendritic plexus of displaced cholinergic amacrine cells. The retinal distribution of synaptoporin, a synaptic vesicle associated protein, was studied. Strong reduction of immunolabelling was observed in the two cholinergic strata. The anatomical findings are discussed in the context of models of the DS circuitry of the mammalian retina.


Sign in / Sign up

Export Citation Format

Share Document