A horizontal cell selectively contacts blue-sensitive cones in cyprinid fish retina : intracellular staining with horseradish peroxidase

1988 ◽  
Vol 235 (1280) ◽  
pp. 281-287 ◽  
Keyword(s):  
Horseradish Peroxidase ◽  
Negative Feedback ◽  
Horizontal Cell ◽  
Cyprinid Fish ◽  
Horizontal Cells ◽  
Intracellular Staining ◽  
Yellow Orange ◽  
Fish Retina ◽  
Feedback Pathway

A horizontal cell selectively contacting blue-sensitive cones has been intracellularly stained with horseradish peroxidase in the retina of a cyprinid fish, the roach. The light microscopical morphology of the cell belonged to the H3 category of horizontal cells found in cyprinid fish retinae. In response to spectral stimuli, the cell generated chromaticity-type S-potentials that were hyperpolarizing to blue and depolarizing to yellow-orange. A red-sensitive hyperpolarizing component was absent possibly because of suppression of the negative feedback pathway between luminosity-type (H1) horizontal cells and green-sensitive cones.

Plasticity of cone horizontal cell functioning in cyprinid fish retina: effects of background illumination of moderate intensity

1988 ◽  
Vol 17 (5) ◽  
pp. 701-710 ◽  
Author(s):  
M. B. A. Djamgoz ◽  
J. E. G. Downing ◽  
M. Kirsch ◽  
D. J. Prince ◽  
H. -J. Wagner
Keyword(s):  
Horizontal Cell ◽  
Cyprinid Fish ◽  
Moderate Intensity ◽  
Background Illumination ◽  
Fish Retina

Cobalt ions inhibit negative feedback in the outer retina by blocking hemichannels on horizontal cells

2004 ◽  
Vol 21 (4) ◽  
pp. 501-511 ◽  
Author(s):  
I. FAHRENFORT ◽  
T. SJOERDSMA ◽  
H. RIPPS ◽  
M. KAMERMANS
Keyword(s):  
Negative Feedback ◽  
Glutamate Release ◽  
Horizontal Cell ◽  
Activation Function ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Small Shift ◽  
Cobalt Ions ◽  
Low Concentrations ◽  
Spectral Coding

In goldfish, negative feedback from horizontal cells to cones shifts the activation function of the Ca2+ current of the cones to more negative potentials. This shift increases the amount of Ca2+ flowing into the cones, resulting in an increase in glutamate release. The increased glutamate release forms the basis of the feedback-mediated responses in second-order neurons, such as the surround-induced responses of bipolar cells and the spectral coding of horizontal cells. Low concentrations of Co2+ block these feedback-mediated responses in turtle retina. The mechanism by which this is accomplished is unknown. We studied the effects of Co2+ on the cone/horizontal network of goldfish retina and found that Co2+ greatly reduced the feedback-mediated responses in both cones and horizontal cells in a GABA-independent way. The reduction of the feedback-mediated responses is accompanied by a small shift of the Ca2+ current of the cones to positive potentials. We have previously shown that hemichannels on the tips of the horizontal cell dendrites are involved in the modulation of the Ca2+ current in cones. Both the absence of this Co2+-induced shift of the Ca2+ current in the absence of a hemichannel conductance and the sensitivity of Cx26 hemichannels to low concentrations of Co2+ are consistent with a role for hemichannels in negative feedback from horizontal cells to cones.

Neural interactions between cone photoreceptors and horizontal cells in the turtle (Mauremys caspica) retina

1998 ◽  
Vol 15 (1) ◽  
pp. 1-13 ◽  
Author(s):  
HUSAM ASI ◽  
IDO PERLMAN
Keyword(s):  
Negative Feedback ◽  
Cascade Model ◽  
Horizontal Cells ◽  
Cone Photoreceptors ◽  
Action Spectra ◽  
Inhibitory Feedback ◽  
Neural Interactions ◽  
Chromatic Properties ◽  
Feedback Pathway ◽  
Mauremys Caspica

Horizontal cells and cone photoreceptors in the vertebrate retina are interconnected by a complex network of synapses leading to the generation of color-coded responses in chromaticity horizontal cells. A simple cascade model of excitatory feedforward and inhibitory feedback synapses had been suggested to underlie these observations. In this study, the photoresponses of cones and horizontal cells were recorded intracellularly from the turtle eyecup. Three different approaches were adopted in order to test quantitatively the cascade model. Comparing linearity functions between these neurons indicated multiple excitatory inputs to each type of horizontal cells. The depolarizing photoresponses of R/G C-type horizontal cells were considerably faster than those of L-type horizontal cells but slower than those recorded from L-cones. This observation disagrees with the basic assumption of the cascade model that assign the depolarizing photoresponses of R/G C-type horizontal cells to a negative feedback pathway from L-type horizontal cells onto M-cones. Finally, the action spectra of each of the three types of horizontal cells could not be solely accounted for by input from one spectral type of cones. Only by assuming excitatory and inhibitory inputs from all spectral types of cones, the action spectra of all types of horizontal cells could be reconstructed. These findings suggest that the negative feedback pathways from horizontal cells onto cones in the turtle retina cannot solely account for the chromatic properties of the horizontal cells and support a direct inhibitory inputs from cones to turtle horizontal cells.

Endogenous Activation of Dopamine D2 Receptors Regulates Dopamine Release in the Fish Retina

1997 ◽  
Vol 78 (1) ◽  
pp. 439-449 ◽  
Author(s):  
Yu Wang ◽  
Krisztina Harsanyi ◽  
Stuart C. Mangel
Keyword(s):  
Dopamine Release ◽  
Divalent Cations ◽  
Horizontal Cell ◽  
Electrical Coupling ◽  
D2 Receptors ◽  
Horizontal Cells ◽  
Light Stimulation ◽  
Full Field ◽  
Dopamine D2 ◽  
Fish Retina

Wang, Yu, Krisztina Harsanyi, and Stuart C. Mangel. Endogenous activation of dopamine D2 receptors regulates dopamine release in the fish retina. J. Neurophysiol. 78: 439–449, 1997. In the fish retina, horizontal cell electrical coupling and light responsiveness is regulated by activation of dopamine D1 receptors that are located on the horizontal cells themselves. The effects of dopamine and dopamine D2 receptor agonists and antagonists on cone horizontal cell light responses were studied in in vitro superfused goldfish retinas. Horizontal cell light responses and electrical coupling were assessed by monitoring responses to full-field stimuli and to small, centered (0.4 mm diam) spots of light, respectively. Dopamine (0.2–10 μM) application uncoupled horizontal cells and decreased their responses to full-field stimuli. Application of the D2 antagonist eticlopride (10–50 μM) produced similar effects, whereas quinpirole (0.1–10 μM), a D2 agonist, had the opposite effects. The uncoupling effect of eticlopride was blocked by prior application of SCH23390 (10 μM), a D1 receptor antagonist, and was eliminated after destruction of dopaminergic neurons by prior treatment of the retinas with 6-hydroxydopamine. The effects of these D2 drugs were observed following flickering light stimulation, but were not observed following sustained light stimulation. Application of the D2 antagonists sulpiride (0.5–20 μM) and spiperone (0.25–10 μM) uncoupled horizontal cells when the total concentration of divalent cations (Mg2+ and Ca2+) in the Ringer solution was 1.1 mM. However, when the concentration of divalent cations was 0.2 mM, spiperone had no effect on the horizontal cells and sulpiride increased coupling. In contrast, eticlopride uncoupled the cells and decreased their light responsiveness irrespective of the concentration of divalent cations. The effects of quinpirole also depended on the concentration of divalent cations; its coupling effect was reduced when the divalent cation concentration was increased from 0.2 to 1.0 mM. The results suggest that activation of D2 receptors in the fish retina by endogenous dopamine decreases dopamine release and is greater after flickering compared with sustained light stimulation. These D2 receptors thus function as presynaptic autoreceptors that inhibit dopamine release from dopaminergic cells. In addition, the results also indicate that the effectiveness of some D2 drugs at these receptors is dependent on the concentration of divalent cations.

The interplexiform–horizontal cell system of the fish retina: effects of dopamine, light stimulation and time in the dark

1987 ◽  
Vol 231 (1262) ◽  
pp. 91-121 ◽  
Keyword(s):  
Horizontal Cell ◽  
Continuous Light ◽  
Cell System ◽  
Horizontal Cells ◽  
Dopamine Antagonist ◽  
Intracellular Enzyme ◽  
Full Field ◽  
Small Spot ◽  
Response Onset ◽  
Fish Retina

Interplexiform cells contact cone horizontal cells in the fish retina and probably release dopamine at synaptic sites. The effects of dopamine, certain related compounds, and light and dark régimes were tested on the intracellularly recorded activity of horizontal cells in the superfused carp retina to elucidate the functional role of the interplexiform cell. Dopamine application onto retinae kept in the dark for 30–40 min increased the size of the responses of cone horizontal cells to small-spot stimuli but decreased response size to large- and full-field stimuli. Dopamine also altered the response waveform of these cells; the transient at response onset increased in size and the depolarizing afterpotential decreased in size. Haloperidol, a dopamine antagonist, blocked these effects of dopamine application. Forskolin, an adenylate cyclase activator, increased the size of the responses of the cells to small-spot stimuli. Superfusion of vasoactive intestinal peptide did not produce any effects on horizontal cells. The results indicate that dopamine produces multiple physiological effects on cone horizontal cells by activation of an intracellular enzyme system. We propose that some of these effects are probably related to an uncoupling of the gap junctions between horizontal cells, but that other effects are most likely not explained on this basis and reflect additional changes induced in the cells by dopamine. After prolonged periods of darkness (100–110 min), compared with short periods (30–40 min), L-type cone horizontal cells exhibited responses similar to those obtained during dopamine application. Dim flick­ering or continuous light backgrounds did not mimic the effects of dopamine. Although dopamine application onto retinae after short-term darkness produced dramatic effects on L-type cone horizontal cells, little or no effect was observed when dopamine was applied while the effects of a previous dopamine application were still present or after prolonged darkness. These results suggest that interplexiform cells may release dopamine after prolonged darkness and that interplexiform cells may regulate lateral inhibitory effects mediated by L-type cone horizontal cells as a function of time in the dark.

The feedforward component in depolarizing red responses of R/G horizontal cells in carp retina

2000 ◽  
Vol 17 (6) ◽  
pp. 919-924 ◽  
Author(s):  
JIAN-FENG HU ◽  
PEI-JI LIANG
Keyword(s):  
Negative Feedback ◽  
Dynamic Characteristics ◽  
Horizontal Cells ◽  
Inhibitory Input ◽  
Background Illumination ◽  
Response Dynamics ◽  
Light Responses ◽  
Significant Difference ◽  
Green Background ◽  
Feedback Pathway

Light responses of R/G chromaticity-type horizontal cells (R/G HCs) and luminosity-type horizontal cells (LHCs) were intracellularly recorded in isolated superfused carp retina, and the response dynamics analyzed. The results revealed that (1) No significant difference in delay was detected between R/G HC red and green responses; (2) The rising speed was quicker for R/G HC depolarizing red responses compared to that of its hyperpolarizing green responses; and (3) Dynamic characteristics of R/G HC red responses and its changes caused by green background illumination did not follow that of LHC red response. All these results suggest that the depolarizing response of the R/G HCs cannot be entirely mediated by the negative feedback pathway from LHCs onto cones. A direct inhibitory input from red cones to R/G HCs may exist.

The Open- and Closed-Loop Gain-Characteristics of the Cone/Horizontal Cell Synapse in Goldfish Retina

2000 ◽  
Vol 84 (3) ◽  
pp. 1256-1265 ◽  
Author(s):  
D. A. Kraaij ◽  
H. Spekreijse ◽  
M. Kamermans
Keyword(s):  
Synaptic Transmission ◽  
Negative Feedback ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Strongly Nonlinear ◽  
Highly Nonlinear ◽  
Gain Characteristic ◽  
Cell Synapse ◽  
Goldfish Retina

Under constant light-adapted conditions, vision seems to be rather linear. However, the processes underlying the synaptic transmission between cones and second-order neurons (bipolar cells and horizontal cells) are highly nonlinear. In this paper, the gain-characteristics of the transmission from cones to horizontal cells and from horizontal cells to cones are determined with and without negative feedback from horizontal cells to cones. It is shown that 1) the gain-characteristic from cones to horizontal cells is strongly nonlinear without feedback from horizontal cells, 2) the gain-characteristic between cones and horizontal cells becomes linear when feedback is active, and 3) horizontal cells feed back to cones via a linear mechanism. In a quantitative analysis, it will be shown that negative feedback linearizes the synaptic transmission between cones and horizontal cells. The physiological consequences are discussed.

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