Distribution of GABA-immunoreactive amacrine cell synapses in the inner plexiform layer of macaque monkey retina

1990 ◽  
Vol 5 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Margaret A. Koontz ◽  
Anita E. Hendrickson

AbstractThe distribution patterns of GABA immunoreactive (+) and immunonegative (−) amacrine cell synapses and profiles in the inner plexiform layer (IPL) were analyzed in three macaque monkey retinas using postembedding electron-microscopic (EM) immunogold cytochemistry. Synapses and profiles were counted at 5% intervals throughout the IPL depth in three EM montages (total area = 6509 μm2), with 0% depth at the inner nuclear layer/IPL border. Nearly 70% of all amacrine synapses were GABA+, and they contacted all major classes of neurons that arborize in the IPL: bipolars (45%), ganglion cells (25%), and GABA+ (20%) and GABA− (10%) amacrines. A major relationship was seen between GABA+ amacrine processes and bipolar terminals: 76% of all amacrine-to-bipolar synapses were GABA+, and 82% of bipolar output dyads contained at least one GABA+ amacrine.GABA+ amacrine profiles (N = 2455) were concentrated in three wide bands at IPL depths of 0–25%, 40–60%, and 75–100%, corresponding to the dense bands seen with light-microscopic immunocytochemistry. In contrast, GABA+ amacrine synapses (N = 1081) were distributed evenly throughout the IPL depth, rather than being confined to the three dense bands. GABA− amacrine synapses (N = 516) were concentrated at 40% and 60% depths.Each category of amacrine output synapses had a characteristic pattern of stratification in the IPL. GABA+amacrine-to-bipolar synapses occurred throughout the IPL but were most frequent at 20% and 80% IPL depths, where the dendrites of midget cone bipolars arborize (Polyak, 1941). In contrast, GABA+amacrine-to-ganglion cell synapses were concentrated at 30% and 70% IPL depths, near the dendritic arborizations of parasol ganglion cells (Watanabe & Rodieck, 1989). GABA+ synapses onto bipolars and amacrines were also concentrated at the level of rod bipolar terminals. GABA+ amacrines must play significant but different roles in ON and OFF midget and parasol pathways as well as the rod pathway.

1993 ◽  
Vol 10 (5) ◽  
pp. 907-914 ◽  
Author(s):  
Charles L. Zucker ◽  
Berndt Ehinger

AbstractThe distribution of glycine receptors in the turtle retina was studied with the aid of a monoclonal antibody that detects the 93-kD protein associated with the strychnine-sensitive glycine receptor. Light microscopically, receptors were found in the inner plexiform layer and, more sparsely, in the innermost parts of the inner nuclear layer. No receptors were seen to be associated with photoreceptor cells, horizontal cells, or any other structures in the distal inner nuclear layer or outer plexiform layer. Ultrastructurally, glycine receptors were found on the inner face of postsynaptic membranes of processes from amacrine and presumed ganglion cells and always involved amacrine cell processes as the presynaptic element. Such glycine receptor immunoreactive synapses onto amacrine cell processes were distributed throughout the inner plexiform layer with a peak density near the middle. On the other hand, output synapses onto ganglion cell processes displaying immunoreactive glycine receptor sites showed a bimodal distribution in the inner plexiform layer. Glycine receptor immunoreactivity was not detected on bipolar cells, but presumed glycine-utilizing processes (i.e. those presynaptic to immunoreactive glycine receptors) were occasionally found to be postsynaptic in bipolar cell dyads. The majority of the synaptic input to the presumed glycine-utilizing amacrine cell processes was from other amacrine processes, some of which were themselves glycine utilizing. The observations suggest that glycinergic synapses in the turtle retina are, to a large extent, engaged in processing interamacrine signals.


1997 ◽  
Vol 14 (6) ◽  
pp. 1089-1096 ◽  
Author(s):  
Bao-Song Zhu ◽  
Ian L. Gibbins

AbstractThe entire population of ganglion cells in the retina of the toad Bufo marinus was labeled by retrograde transport of a lysine-fixable biotinylated dextran amine of 3000 molecular weight. Synaptic connections between bipolar, amacrine, and ganglion cells in the inner plexiform layer were quantitatively analyzed, with emphasis on synaptic inputs to labeled ganglion cell dendrites. Synapses onto ganglion cell dendrites comprised 47% of a total of 1234 identified synapses in the inner plexiform layer. Approximately half of the bipolar or amacrine cell synapses were directed onto ganglion cell dendrites, while the rest were made mainly onto amacrine cell dendrites. Most of the synaptic inputs to ganglion cell dendrites derived from amacrine cell dendrites (84%), with the rest from bipolar cell terminals. Synaptic inputs to ganglion cell dendrites were distributed relatively uniformly throughout all sublaminae of the inner plexiform layer. The present study provides unambiguous identification of ganglion cell dendrites including very fine processes, enabling a detailed analysis of the types and distribution of synaptic inputs from the bipolar and amacrine cell to the ganglion cells. The retrograde tracing technique used in the present study will prove to be a useful tool for identifying synaptic inputs to ganglion cell dendrites from neurochemically identified bipolar and amacrine cell types in the retina.


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.


1990 ◽  
Vol 4 (6) ◽  
pp. 533-545 ◽  
Author(s):  
Bernd Fritzsch ◽  
Shaun P. Collin

AbstractThe distribution of ganglion cells in the retina of the silver lamprey, Ichthyomyzon unicuspis, was revealed by retrograde labeling from the optic nerve with horseradish peroxidase (HRP) and fluorescent-labeled dextrans in live animals and with the fluorescent dye DiI in aldehyde-fixed tissue. The majority of ganglion cells (74%) termed the “outer ganglion cells,” are multipolar and are located at the vitread boundary of the inner nuclear layer. The remaining ganglion cells (26%), termed the “inner ganglion cells” are bipolar and are distributed in a sublamina within the inner plexiform layer. The dense, dendritic meshwork of the outer ganglion cells is largely restricted to the sclerad half of the inner plexiform layer with some cells possessing dendrites which pass through the inner nuclear layer to terminate within the outer plexiform layer. The dendrites of the inner ganglion cells form a thin, dendritic network apposing the inner limiting membrane. Axons from both populations of ganglion cells originate from dendrites or the soma and form fascicles lying adjacent to the outer ganglion cell somata.Retinopetal fibers, originating from bilaterally distributed neurons of the tegmental midbrain, were thin and varicose and ran parallel to the ganglion cell axons to terminate either with a varicose enlargement or a few short sidebranches in the sclerad third of the inner plexiform layer. The unusual organization of the lamprey retina and outgroup comparison with hagfish suggests that agnathans share a presumably primitive type of retinal ganglion cell organization compared to that of gnathostomes.


2002 ◽  
Vol 19 (3) ◽  
pp. 299-305 ◽  
Author(s):  
DAVID W. MARSHAK ◽  
ELIZABETH S. YAMADA ◽  
ANDREA S. BORDT ◽  
WENDY C. PERRYMAN

A labeled ON parasol ganglion cell from a macaque retina was analyzed in serial, ultrathin sections. It received 13% of its input from diffuse bipolar cells. These directed a large proportion of their output to amacrine cells but received a relatively small proportion of their amacrine cell input via feedback synapses. In these respects, they were similar to the DB3 bipolar cells that make synapses onto OFF parasol cells. Bipolar cell axons that contacted the ON parasol cell in stratum 4 of the inner plexiform layer always made synapses onto the dendrite, and therefore, the number of bipolar cell synapses onto these ganglion cells could be estimated reliably by light microscopy in the future. Amacrine cells provided the majority of inputs to the ON parasol cell. Only a few of the presynaptic amacrine cell processes received inputs from the same bipolar cells as the parasol cells, and most of the presynaptic amacrine cell processes did not receive any inputs at all within the series. These findings suggest that most of the inhibitory input to the ON parasol cell originates from other areas of the retina. Amacrine cells presynaptic to the parasol ganglion cell interacted very infrequently with other neurons in the circuit, and therefore, they would be expected to act independently, for the most part.


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.


2011 ◽  
Vol 28 (3) ◽  
pp. 205-220 ◽  
Author(s):  
MARTIN WILSON ◽  
NICK NACSA ◽  
NATHAN S. HART ◽  
CYNTHIA WELLER ◽  
DAVID I. VANEY

AbstractUsing both NADPH diaphorase and anti-nNOS antibodies, we have identified—from retinal flatmounts—neuronal types in the inner retina of the chicken that are likely to be nitrergic. The two methods gave similar results and yielded a total of 15 types of neurons, comprising 9 amacrine cells, 5 ganglion cells, and 1 centrifugal midbrain neuron. Six of these 15 cell types are ubiquitously distributed, comprising 3 amacrine cells, 2 displaced ganglion cells, and a presumed orthotopic ganglion cell. The remaining nine cell types are regionally restricted within the retina. As previously reported, efferent fibers of midbrain neurons and their postsynaptic partners, the unusual axon-bearing target amacrine cells, are entirely confined to the ventral retina. Also confined to the ventral retina, though with somewhat different distributions, are the “bullwhip” amacrine cells thought to be involved in eye growth, an orthotopic ganglion cell, and two types of large axon-bearing amacrine cells whose dendrites and axons lie in stratum 1 of the inner plexiform layer (IPL). Intracellular fills of these two cell types showed that only a minority of otherwise morphologically indistinguishable neurons are nitrergic. Two amacrine cells that branch throughout the IPL are confined to an equatorial band, and one small-field orthotopic ganglion cell that branches in the proximal IPL is entirely dorsal. These findings suggest that the retina uses different processing on different regions of the visual image, though the benefit of this is presently obscure.


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.


1998 ◽  
Vol 15 (2) ◽  
pp. 377-387 ◽  
Author(s):  
BETH B. PETERSON ◽  
DENNIS M. DACEY

Ganglion cells with intraretinal axon collaterals have been described in monkey (Usai et al., 1991), cat (Dacey, 1985), and turtle (Gardiner & Dacey, 1988) retina. Using intracellular injection of horseradish peroxidase and Neurobiotin in in vitro whole-mount preparations of human retina, we filled over 1000 ganglion cells, 19 of which had intraretinal axon collaterals and wide-field, spiny dendritic trees stratifying in the inner half of the inner plexiform layer. The axons were smooth and thin (∼2 μm) and gave off thin (<1 μm), bouton-studded terminal collaterals that extended vertically to terminate in the outer half of the inner plexiform layer. Terminal collaterals were typically 3–300 μm in length, though sometimes as long as 700 μm, and were present in clusters, or as single branched or unbranched varicose processes with round or somewhat flattened lobular terminal boutons 1–2 μm in diameter. Some cells had a single axon whereas other cells had a primary axon that gave rise to 2–4 axon branches. Axons were located either in the optic fiber layer or just beneath it in the ganglion cell layer, or near the border of the ganglion cell layer and the inner plexiform layer. This study shows that in the human retina, intraretinal axon collaterals are associated with a morphologically distinct ganglion cell type. The synaptic connections and functional role of these cells are not yet known. Since distinct ganglion cell types with intraretinal axon collaterals have also been found in monkey, cat, and turtle, this cell type may be common to all vertebrate retinas.


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