scholarly journals B-wave of the electroretinogram. A reflection of ON bipolar cell activity.

1989 ◽  
Vol 93 (1) ◽  
pp. 101-122 ◽  
Author(s):  
R A Stockton ◽  
M M Slaughter
Keyword(s):  
Bipolar Cell ◽  
Horizontal Cell ◽  
Cell Activity ◽  
Bipolar Cells ◽  
Extracellular Potassium ◽  
Retinal Neurons ◽  
Third Order ◽  
Extracellular Potassium Concentration ◽  
Cell Depolarization ◽  
D Wave

Light-evoked intraretinal field potentials (electroretinogram, ERG) have been measured simultaneously with extracellular potassium fluxes in the amphibian retina. The application of highly selective pharmacologic agents permitted us to functionally isolate various classes of retinal neurons. It was found that: (a) application of APB (2-amino-4-phosphonobutyrate), which has previously been shown to selectively abolish the light responsiveness of ON bipolar cells, causes a concomitant loss of the ERG b-wave and ON potassium flux. (b) Conversely, PDA (cis 2,3-piperidine-dicarboxylic acid) or KYN (kynurenic acid), which have been reported to suppress the light responses of OFF bipolar, horizontal, and third-order retinal neurons, causes a loss of the ERG d-wave as well as OFF potassium fluxes. The b-wave and ON potassium fluxes, however, remain undiminished. (c) NMA (N-methyl-DL-aspartate) or GLY (glycine), which have been reported to suppress the responses of third-order neurons, do not diminish the b- or d-waves, nor the potassium fluxes at ON or OFF. This leads to the conclusion that the b-wave of the ERG is a result of the light-evoked depolarization of the ON bipolar neurons. This experimental approach has resulted in two further conclusions: (a) that the d-wave is an expression of OFF bipolar and/or horizontal cell depolarization at the termination of illumination and (b) that light-induced increases in extracellular potassium concentration in both the inner (proximal) and outer (distal) retina are the result of ON bipolar cell depolarization.

Receptive field of the retinal bipolar cell: a pharmacological study in the tiger salamander

1996 ◽  
Vol 76 (3) ◽  
pp. 2005-2019 ◽  
Author(s):  
W. A. Hare ◽  
W. G. Owen
Keyword(s):  
Receptive Field ◽  
Gaba Receptors ◽  
Bipolar Cell ◽  
Horizontal Cell ◽  
Pharmacological Study ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Gaba Uptake ◽  
Gamma Aminobutyric Acid ◽  
Gabaergic Synapse

1. It is widely believed that signals contributing to the receptive field surrounds of retinal bipolar cells pass from horizontal cells to bipolar cells via GABAergic synapses. To test this notion, we applied gamma-aminobutyric acid (GABA) agonists and antagonists to isolated, perfused retinas of the salamander Ambystoma tigrinum while recording intracellularly from bipolar cells, horizontal cells, and photoreceptors. 2. As we previously reported, administration of the GABA analogue D-aminovaleric acid in concert with picrotoxin did not block horizontal cell responses or the center responses of bipolar cells but blocked the surround responses of both on-center and off-center bipolar cells. 3. Surround responses were not blocked by the GABA, antagonists picrotoxin or bicuculline, the GABAB agonist baclofen or the GABAB antagonist phaclofen, and the GABAC antagonists picrotoxin or cis-4-aminocrotonic acid. Combinations of these drugs were similarly ineffective. 4. GABA itself activated a powerful GABA uptake mechanism in horizontal cells for which nipecotic acid is a competitive agonist. It also activated, both in horizontal cells and bipolar cells, large GABAA conductances that shunted light responses but that could be blocked by picrotoxin or bicuculline. 5. GABA, administered together with picrotoxin to block the shunting effect of GABAA activation, did not eliminate bipolar cell surround responses at concentrations sufficient to saturate the known types of GABA receptors. 6. Surround responses were not blocked by glycine or its antagonist strychnine, or by combinations of drugs designed to eliminate GABAergic and glycinergic pathways simultaneously. 7. Although we cannot fully discount the involvement of a novel GABAergic synapse, the simplest explanation of our findings is that the primary pathway mediating the bipolar cell's surround is neither GABAergic nor glycinergic.

Different types of synapses with different spectral types of cones underlie color opponency in a bipolar cell of the turtle retina

1999 ◽  
Vol 16 (5) ◽  
pp. 801-809 ◽  
Author(s):  
SILKE HAVERKAMP ◽  
WOLFGANG MÖCKEL ◽  
JOSEF AMMERMÜLLER
Keyword(s):  
Bipolar Cell ◽  
Metabotropic Glutamate Receptors ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Color Processing ◽  
Ionotropic Receptors ◽  
Metabotropic Glutamate ◽  
Different Types ◽  
Color Opponency

Electrophysiologically, color-opponent retinal bipolar cells respond with opposite polarities to stimulation with different wavelengths of light. The origin of these different polarities in the same bipolar cell has always been a mystery. Here we show that an intracellularly recorded and HRP-injected, red-ON, blue/green-OFF bipolar cell of the turtle retina made invaginating (ribbon associated) synapses exclusively with L-cones. Non-invaginating synapses resembling wide-cleft basal junctions were made exclusively with M-cones. Input from S-cones was not seen. From these results we suggest sign-inverting transmission from L-cones at invaginating synapses via metabotropic glutamate receptors, and sign-conserving transmission from M-cones at wide-cleft basal junctions via ionotropic receptors. To explain the pronounced blue sensitivity of the bipolar cell, computer simulations were performed using a sign-conserving input from a yellow/blue chromaticity-type (H3) horizontal cell. The response properties of the red-ON, blue/green-OFF bipolar cell could be quantitatively reproduced by this means. The simulation also explained the asymmetry in L- and M-cone inputs to the bipolar cell as found in the ultrastructural analysis and assigned a putative role to H3 horizontal cells in color processing in the turtle retina.

Contribution of rod, on-bipolar, and horizontal cell light responses to the ERG of dogfish retina

1999 ◽  
Vol 16 (3) ◽  
pp. 503-511 ◽  
Author(s):  
R.A. SHIELLS ◽  
G. FALK
Keyword(s):  
Bipolar Cell ◽  
Time Course ◽  
Horizontal Cell ◽  
Full Range ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Negative Wave ◽  
Low Light ◽  
Cell Responses ◽  
Light Intensities

Simultaneous extracellular ERG and intracellular recordings from horizontal and ON-bipolar cells were obtained from the dark-adapted retina of the dogfish. The light intensity–peak response relation (IR) and time course of on-bipolar cell responses closely resembled that of the ERG b-wave, but only at low light intensities [<10 rhodopsin molecules bleached per rod (Rh*)]. Block of on-bipolar cell responses with 50 μM 2-amino-4-phosphonobutyrate (APB) abolished the b-wave and unmasked a vitreal-negative wave. Subtraction from the control ERG resulted in the isolation of a vitreal-positive ERG with an IR which matched that of on-bipolar cells over the full range of light intensities. The D.C. component of the ERG arises as a result of sustained depolarization of on-bipolar cells in response to long (>0.5 s) dim light stimuli, or following bright light flashes. The IR of horizontal cells and the vitreal-negative wave unmasked by APB could be matched by scaling at low light intensities (<5 Rh*). However, horizontal cell responses saturated at about 30 Rh*, while the vitreal-negative wave continued to increase in amplitude. The time course of horizontal cell membrane current with dim flashes could be matched to the rising phase of the vitreal-negative wave, assuming that the delay in generating the voltage response in horizontal cells is due to their long (100 ms) membrane time constant. Blocking post-photoreceptor activity resulted in a much smaller vitreal-negative wave than that unmasked by APB alone. We conclude that the b-wave arises from on-bipolar cell depolarization, while the leading edge of the a-wave is a composite of the change in extracellular voltage drop across the rod layer and a component (proximal PIII) reflecting a decrease in extracellular K+ as horizontal cell synaptic channels close with light.

scholarly journals Analyses of bipolar cell responses elicited by polarization of horizontal cells.

1982 ◽  
Vol 79 (1) ◽  
pp. 131-145 ◽  
Author(s):  
J Toyoda ◽  
T Kujiraoka
Keyword(s):  
Bipolar Cell ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Na Channels ◽  
Cell Responses ◽  
Ionic Mechanisms ◽  
Cl Channels ◽  
Hyperpolarizing Response ◽  
Conductance Changes

Simultaneous intracellular recordings were made from a bipolar cell and a horizontal cell in the carp retina. The properties of the bipolar cell were studied while injecting current into the horizontal cell. Hyperpolarization of horizontal cells, irrespective of their type, elicited a hyperpolarizing response in on-center bipolar cells and a depolarizing response in off-center bipolar cells. Analyses of the ionic mechanisms of bipolar cell responses revealed that depolarization of horizontal cells simulated and hyperpolarization opposed the effect of central illumination. The effect of polarization was exerted in such a manner that each type of horizontal cells modified the transmission from those photoreceptors from which they receive main inputs. In on-center bipolar cells, for example, the L-type horizontal cells receiving inputs mainly from red cones modified the cone-bipolar transmission accompanied by a conductance change of K+ and/or Cl- channels, and the intermediate horizontal cells receiving inputs from rods modified the rod-bipolar transmission accompanied by a conductance change of Na+ channels. In off-center bipolar cells, the effect of polarization of any type of horizontal cells was mediated mainly by conductance changes of Na+ channels. Feedback mechanisms from horizontal cells to photoreceptors could explain these results reasonably well.

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.

Center-surround organization in bipolar cells: Symmetry for opposing contrasts

2003 ◽  
Vol 20 (1) ◽  
pp. 1-10 ◽  
Author(s):  
PATRICK K. FAHEY ◽  
DWIGHT A. BURKHARDT
Keyword(s):  
Bipolar Cell ◽  
Spatial Information ◽  
Horizontal Cell ◽  
Positive Contrast ◽  
Bipolar Cells ◽  
Ambystoma Tigrinum ◽  
Maximal Response ◽  
Response Curves ◽  
Contrast Polarity ◽  
Contrast Gain

Intracellular recordings were obtained from 73 cone-driven bipolar cells in the light-adapted retina of the tiger salamander (Ambystoma tigrinum). Responses to flashes of negative and positive contrast for centered spots and concentric annuli of optimum spatial dimensions were analyzed as a function of contrast magnitude. For both depolarizing and hyperpolarizing bipolar cells, it was found that remarkably similar responses were observed for the center and surround when comparisons were made between responses of the same response polarity and thus, responses to opposite contrast polarity. Thus, spatial information and contrast polarity appear to be rather strongly confounded in many bipolar cells. As a rule, the form of the contrast/response curves for center and surround approximated mirror images of each other. Contrast gain and C50 (the contrast required for half-maximal response) were quantitatively similar for center and surround when comparisons were made for responses of the same response polarity. The average contrast gain of the bipolar cell surround was 3–5 times higher than that measured for horizontal cells. Contrast/latency measurements and interactions between flashed spots and annuli showed that the surround response is delayed by 20–80 ms with respect to that of the receptive-field center. Cones showed no evidence for center-surround antagonism while for bipolar cells, the average strength of the surround ranged from about 50% to 155% of the center, depending on the test and response polarity. The results of experiments on the effects of APB (100 μM) on depolarizing bipolar cells suggest that the relative contribution of the feedback pathway (horizontal cell to cones) and the feedforward pathway (horizontal cell to bipolar cell) to the bipolar surround varies in a distributed manner across the bipolar cell population.

Synapse formation and modification between distal retinal neurons in larval and juvenile Xenopus

1981 ◽  
Vol 211 (1184) ◽  
pp. 373-389 ◽  
Keyword(s):  
Bipolar Cell ◽  
Synapse Formation ◽  
Developmental Stages ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Cell Junction ◽  
Ribbon Synapses ◽  
Cell Processes ◽  
Chemical Synapses

A serial section analysis of photoreceptor synaptic bases was undertaken in the clawed frog Xenopus laevis . The developmental period from tadpole stage 48 through metamorphosis was studied. Horizontal cells contacted rod and cone photoreceptors at ribbon synapses; the number of such contacts per receptor base was constant for rods, but increased for cones as a function-of developmental stage. In pre-metamorphic animals bipolar cells contacted receptors only through basal junctions; their number in cone bases increased dramatically during development but was unchanged in rod bases. A densitometric estimation of the cleft width of basal junctions showed that it ranged from 10 to 18 nm, but the junctions could not be divided reliably into the ‘wide’ and ‘narrow’ categories reported for other vertebrate species. Near metamorphic climax a new type of ribbon-related bipolar cell junction appeared. Gap junctions between horizontal cells and conventional chemical synapses of horizontal cell onto bipolar cell processes were first seen in mid-larval developmental stages.

Bipolar cells in the zebrafish retina

2010 ◽  
Vol 28 (1) ◽  
pp. 77-93 ◽  
Author(s):  
V.P. CONNAUGHTON
Keyword(s):  
Bipolar Cell ◽  
Developmental Stages ◽  
Cell Activity ◽  
Cell Types ◽  
Bipolar Cells ◽  
Retinal Cell ◽  
Developmental Studies ◽  
Comprehensive Overview ◽  
Zebrafish Model ◽  
Toxicological Studies

AbstractZebrafish are an existing model for genetic and developmental studies due to their rapid external development and transparent embryos, which allow easy manipulation and observation of early developmental stages. The application of the zebrafish model to vision research has allowed for examination of retinal development and the characteristics of different retinal cell types, including bipolar cells. In particular, bipolar cell development, including differentiation, maturation, and gene expression, has been documented, as has physiological properties, such as voltage- and ligand-gated currents, and neurotransmitter receptor and ion channel expression. Mutant strains and transgenic lines have been used to document how bipolar cell connections and/or development may be altered, and toxicological studies examining how environmental factors may impact bipolar cell activity have been performed. The purpose of this paper was to review the existing literature on zebrafish bipolar cells, to provide a comprehensive overview of current information pertaining to this retinal cell type.

Organization of the outer synaptic layer in the retina of the larval tiger Salamander

1973 ◽  
Vol 265 (872) ◽  
pp. 471-489 ◽  
Keyword(s):  
Bipolar Cell ◽  
Photoreceptor Cell ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Tiger Salamander ◽  
Serial Sections ◽  
Rods And Cones ◽  
Cell Processes ◽  
Rod Cell

The organization of the outer synaptic layer in the salamander retina was studied electronmicroscopically in serial sections of tissue prepared by conventional techniques or stained by the method of Golgi. Rod cell pedicles make ribbon junctions on cone cell processes, and rod cell processes invaginate cone pedicles without otherwise making any specialized contact with them. Horizontal cells make ribbon and distal junctions with the photoreceptor cell pedicles; a single horizontal cell may contact both rods and cones. Bipolar cells were observed to make either ribbon or basal junctions with the photoreceptor cell pedicles; in addition, certain processes believed to belong to bipolar cells make both ribbon and basal junctions with the same or different pedicles. A single bipolar cell may make contact with both rods and cones. Horizontal cells synapse on bipolar cell dendrites and on certain unidentified processes which in turn are also presynaptic to bipolar cells. Ascending branches of these processes invaginate deeply the rod and cone pedicles without otherwise engaging them in any junction. Horizontal cell processes are linked by two kinds of junctions: close membrane appositions, and contacts analogous to the distal junctions between horizontal cells and rod pedicles.

Physiological and pharmacological analysis of suppressive rod-cone interaction in Necturus retina [corrected]

1989 ◽  
Vol 61 (4) ◽  
pp. 866-877 ◽  
Author(s):  
T. Eysteinsson ◽  
T. E. Frumkes
Keyword(s):  
Light Adaptation ◽  
Horizontal Cell ◽  
Red Light ◽  
Background Field ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Lead Chloride ◽  
Inhibitory Influence ◽  
Third Order ◽  
Small Spot

1. Intracellular recordings were obtained from retinal neurons of the mudpuppy, Necturus, while superfusing the eyecup with various pharmacologic agents. In most experiments, the retina was continuously stimulated with a small spot of red light that was centered over the recording electrode and flickering at rates too fast for amphibian rods to follow. The retina was additionally stimulated intermittently with a dim, spatially diffuse background field of 520 nm wavelength. 2. In general, the dim background greatly enhanced flicker responsiveness. We (16) previously called this effect suppressive rod-cone interaction (SRCI) and showed it reflects a tonic suppressive influence on cone pathways that is removed by selective rod-light adaptation. 3. Lead chloride has been claimed to selectively block rod-related retinal responses (13, 35). While recording from horizontal cells lead chloride decreases responses to the dim, diffuse light flashes, enhances the frequency entrained response attributable to cones, and eliminates a background influence on flicker responses. 4. O-phospho-D-serine (DOP), kynurenic acid (KyA), and piperidine dicarboxylic acid are known to act on horizontal cells as antagonists of the photoreceptor neurotransmitter (26, 32, 33). In both depolarizing and hyperpolarizing bipolar cells, these agents enhance flicker responsiveness with no background present and prevent background enhancement of flicker. 5. Mudpuppy cones were found to have a receptive-field surround, which under our stimulus conditions is attributable to rod input. KyA, which is unknown to have any direct influence on photoreceptors, totally blocks this surround mechanism. This indicates that the cone-surround mechanism is attributable to horizontal cell feedback. The influence of KyA on SRCI in cones is similar to that observed in recordings from depolarizing bipolar cells. 6. Most sustained third-order neurons demonstrate SRCI. In these cells, SRCI is blocked by DOP or KyA. Most ON-OFF neurons fail to demonstrate SRCI under control circumstances. The ON-response of these cells is blocked by 2-amino-4-phosphonobutyric acid (31) which leaves the OFF-response intact. While their ON-response is blocked, ON-OFF neurons demonstrate SRCI. 7. The foregoing results indicate that SRCI reflects a tonic, inhibitory influence of horizontal cells on cone pathways that is removed by light-adapting rods. In part, SRCI must involve horizontal cell feedback onto cones. SRCI in third-order neurons appears to largely reflect distal retinal processing.

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