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

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.

Depletion of retinal dopamine does not affect the ERG b-wave increment threshold function in goldfish in vivo

1994 ◽  
Vol 11 (4) ◽  
pp. 695-702 ◽  
Author(s):  
Zheng-Shi Lin ◽  
Stephen Yazulla
Keyword(s):  
Horizontal Cell ◽  
Threshold Function ◽  
Photopic Vision ◽  
Threshold Functions ◽  
Increment Threshold ◽  
Intensity Response ◽  
Purkinje Shift ◽  
6 Hydroxydopamine ◽  
Fish Retina

AbstractIncrement threshold functions of the electroretinogram (ERG) b–wave were obtained from goldfish using an in vivo preparation to study intraretinal mechanisms underlying the increase in perceived brightness induced by depletion of retinal dopamine by 6–hydroxydopamine (6–OHDA). Goldfish received unilateral intraocular injections of 6–OHDA plus pargyline on successive days. Depletion of retinal dopamine was confirmed by the absence of tyrosine-hydroxylase immunoreactivity at 2 to 3 weeks postinjection as compared to sham-injected eyes from the same fish. There was no difference among normal, sham-injected or 6–OHDA-injected eyes with regard to ERG waveform, intensity-response functions or increment threshold functions. Dopamine-depleted eyes showed a Purkinje shift, that is, a transition from rod-to-cone dominated vision with increasing levels of adaptation. We conclude (1) dopamine-depleted eyes are capable of photopic vision; and (2) the ERG b–wave is not diagnostic for luminosity coding at photopic backgrounds. We also predict that (1) dopamine is not required for the transition from scotopic to photopic vision in goldfish; (2) the ERG b–wave in goldfish is influenced by chromatic interactions; (3) horizontal cell spinules, though correlated with photopic mechanisms in the fish retina, are not necessary for the transition from scotopic to photopic vision; and (4) the OFF pathway, not the ON pathway, is involved in the action of dopamine on luminosity coding in the retina.

Acid phosphatase localization in endocytosed horizontal cell gap junctions

1992 ◽  
Vol 8 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Dana K. Vaughan ◽  
Eric M. Lasater
Keyword(s):  
Acid Phosphatase ◽  
Horizontal Cell ◽  
Vesicle Fusion ◽  
White Bass ◽  
Degradative Pathway ◽  
Transport Vesicles ◽  
Subsequent Step ◽  
Degradative Enzymes ◽  
Fish Retina ◽  
Conventional Electron Microscopy

AbstractGap junction (GJ) endocytosis appears to be part of a cycle of GJ renewal in horizontal cells of the teleost fish retina. At least three stages of GJ endocytosis in these neurons have been identified using conventional electron microscopy (EM): invagination of GJ membranes (GJ blebs); free GJ vesicles; and GJ vesicle fusion with mature lysosomes (Vaughan & Lasater, 1990a). In the present study, EM-level acid phosphatase (AP) histochemistry of white bass retina was used to determine at what stage enzymatic degradation of endocytosed GJs begins. Electron-dense AP reaction product was observed within the trans face of the Golgi apparatus, mature lysosomes, and occasional, internal GJ vesicles. In contrast, GJ blebs, peripheral GJ vesicles, and most internal GJ vesicles lacked AP reaction product. These results support the idea that at least some of the GJ vesicles observed within these retinal neurons arise from endocytosis, are on a degradative pathway, and can be termed GJ “endosomes.” Furthermore, GJ vesicles appear to be initially free of AP, but some later acquire it (presumably from transport vesicles bearing degradative enzymes). It is still unclear whether our previous report of GJ vesicle fusion with mature lysosomes is a subsequent step in GJ degradation or part of a different degradative pathway altogether.

Background illumination reduces horizontal cell receptive-field size in both normal and 6-hydroxydopamine-lesioned goldfish retinas

1991 ◽  
Vol 7 (5) ◽  
pp. 441-450 ◽  
Author(s):  
William H. Baldridge ◽  
Alexander K. Ball
Keyword(s):  
Receptive Field ◽  
Dopamine Release ◽  
Horizontal Cell ◽  
Field Size ◽  
Dye Coupling ◽  
Background Illumination ◽  
Receptive Field Size ◽  
Endogenous Dopamine ◽  
6 Hydroxydopamine ◽  
Effect Of Light

AbstractThe effect of background illumination on horizontal cell receptive-field size and dye coupling was investigated in isolated superfused goldfish retinas. Background illumination reduced both horizontal cell receptive-field size and dye coupling. The effect of light on horizontal cell receptive-field size was mimicked by treating the retina with 20 μM dopamine. To test the hypothesis that the effects of light were due to endogenous dopamine release, the effect of light was studied in goldfish retinas in which dopaminergic interplexiform cells were lesioned using 6-hydroxydopamine treatment. In lesioned retinas, background illumination reduced both horizontal cell receptive-field size and dye coupling. Furthermore, the effect of background illumination on unlesioned animals could not be blocked by prior treatment with the D1 dopamine receptor antagonist SCH-23390. These results suggest that, in goldfish retina, dopamine release is not the only mechanism by which horizontal cell receptive-field size could be reduced by light.

Effects of light adaptation on contrast processing in bipolar cells in the retina

2001 ◽  
Vol 18 (4) ◽  
pp. 581-597 ◽  
Author(s):  
PATRICK K. FAHEY ◽  
DWIGHT A. BURKHARDT
Keyword(s):  
Light Adaptation ◽  
Dynamic Range ◽  
Horizontal Cell ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Background Intensity ◽  
Ambystoma Tigrinum ◽  
Background Illumination ◽  
Voltage Range ◽  
Contrast Gain

Effects of light adaptation on contrast processing in the outer retina were investigated over nearly four decades of background illumination by analyzing the intracellular responses of 111 bipolar cells, 66 horizontal cells, and 22 cone photoreceptors in the superfused eyecup of the tiger salamander (Ambystoma tigrinum). Light adaptation had striking and similar effects on the average contrast responses of the hyperpolarizing (Bh) and depolarizing (Bd) classes of bipolar cells: Over the lower two decades of background illumination, the contrast gain increased 7-fold to reach values as high as 20–30, the dynamic range and the half-maximum contrast decreased by about 60%, the total voltage range increased some 40%, and contrast dominance changed from highly positive to more balanced. At higher levels of background, most aspects of the contrast response stabilized and Weber's Law then held closely. In this background range, the contrast gain of bipolar cells was amplified some 20× relative to that of cones whereas the corresponding amplification in horizontal cells was about 6×. Differences in the growth of contrast gain with the intensity of the background illumination for cones versus bipolar cells suggest that there are at least two adaptation-dependent mechanisms regulating contrast gain. One is evident in the cone photoresponse such that an approximately linear relation holds between the steady-state hyperpolarization and contrast gain. The other arises between the voltage responses of the cones and bipolar cells. It could be presynaptic (modulation of cone transmitter release by horizontal cell feedback or other mechanisms) and/or postsynaptic, that is, intrinsic to bipolar cells. Contrast gain grew with the background intensity by a larger factor in horizontal than in bipolar cells. This provides a basis for the widely held view that light adaptation increases the strength of surround antagonism in bipolar cells. On average, the effects of light adaptation and most quantitative indices of contrast processing were remarkably similar for Bd and Bh cells, implying that both classes of bipolar cells, despite possible differences in underlying mechanisms, are about equally capable of encoding all primary aspects of contrast at all levels of light adaptation.

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