Pharmacological study of the chicken's monocular optokinetic nystagmus: Involvement of the ON retinal channel evidenced by the glutamatergic separation of ON and OFF pathways

Bonaventure, N.; Kim, M.S.; Jardon, B.; Yücel, Hasan

doi:10.1016/0042-6989(92)90176-j

Cited by 10 publications

(8 citation statements)

References 32 publications

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“…Iwakabe et al (1997) showed that optokinetic nystagmus (OKN) is depressed in the mGluR6 knockout mouse retina, in which ON responses are abolished, but the surviving nystagmus, presumably activated by the OFF system, displayed an increased preference for reversed directional movement. In chicken, interactions between the ON and OFF channels have been described where each of the pathways generates an OKN with opposite directional preference (Bonaventure et al 1992). These results suggest that the directional OFF response has the capability to influence optokinetic signals, at least when the ON response component is blocked.…”

Section: Discussionmentioning

confidence: 99%

GABA blockade unmasks an OFF response in ON direction selective ganglion cells in the mammalian retina

Ackert

Farajian

Völgyi

et al. 2009

The Journal of Physiology

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One unique subtype of retinal ganglion cell is the direction selective (DS) cell, which responds vigorously to stimulus movement in a preferred direction, but weakly to movement in the opposite or null direction. Here we show that the application of the GABA receptor blocker picrotoxin unmasks a robust excitatory OFF response in ON DS ganglion cells. Similar to the characteristic ON response of ON DS cells, the masked OFF response is also direction selective, but its preferred direction is opposite to that of the ON component. Given that the OFF response is unmasked with picrotoxin, its direction selectivity cannot be generated by a GABAergic mechanism. Alternatively, we find that the direction selectivity of the OFF response is blocked by cholinergic drugs, suggesting that acetylcholine release from presynaptic starburst amacrine cells is crucial for its generation. Finally, we find that the OFF response is abolished by application of a gap junction blocker, suggesting that it arises from electrical synapses between ON DS and polyaxonal amacrine cells. Our results suggest a novel role for gap junctions in mixing excitatory ON and OFF signals at the ganglion cell level. We propose that OFF inputs to ON DS cells are normally masked by a GABAergic inhibition, but are unmasked under certain stimulus conditions to mediate optokinetic signals in the brain.

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Section: Discussionmentioning

confidence: 99%

GABA blockade unmasks an OFF response in ON direction selective ganglion cells in the mammalian retina

Ackert

Farajian

Völgyi

et al. 2009

The Journal of Physiology

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“…Much evidence implicates the ON‐pathway and the retinal cholinergic system in the proper functioning of the optokinetic system. Ablation of the retinal ON‐system with amino‐phosphonobutyric acid leads to severe optokinetic deficits in various vertebrates (Knapp et al ., 1988; Yucel et al ., 1989; Bonaventure et al ., 1992). Likewise, ablation of cholinergic amacrine cells with ethylcholine mustard aziridinium (Millar et al ., 1987) leads to a loss of direction‐selective neurons in the midbrain, and to a loss of OKR in chicken (Reymond & Morgan, 1990; Yang & Morgan, 1990) and rabbit (Amthor et al ., 2002).…”

Section: Functional Considerationsmentioning

confidence: 99%

GABA‐immunoreactive starburst amacrine cells in pigmented and albino rats

Blaszczyk

Telkes

Distler

2004

Eur J of Neuroscience

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In this study we tested whether the critical anatomical substrate for retinal direction selectivity is altered in albino mammals. We used dual immunostaining for GABA and choline acetyltransferase and quantitatively analyzed the number of double-labelled starburst amacrine cells in wild-type and albino rats. In albino rats, the percentage of ON-amacrine cells with high GABA content was significantly lower than in pigmented animals. OFF-amacrines did not significantly differ between the two rat strains. Thus, the decreased GABA content in ON-amacrine cells could reflect an altered neuronal substrate for retinal direction selectivity. These results are discussed in relation to the optokinetic deficits described in albino mammals.

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“…The authors propose a relationship between the adaptational state of the ON or OFF subsystems and the sign of defocus detection, although it remains unclear how they should be differently stimulated in the case of dioptric defocus. Furthermore, in the same study the ON-OFF stimulation was confounded by the underlying flow field and it is known that chickens have a highly asymmetrical optokinetic nystagmus (Bonaventure et al, 1992). This would complicate the brightness changes that are recorded by a local retinal detector, and make it difficult to assign differences in eye growth only to the ON-OFF subsystem.…”

Section: Introductionmentioning

confidence: 99%

“…As ON and OFF responses can be selectively suppressed by drugs (i.e. the glutamate agonist 2-amino-4-phosphoro-butyrate (APB) blocks the retinal ON channel, another glutamate analogue, 2,3-piperidinedicarboxylic acid (PDA), blocks the OFF channel; Bonaventure et al, 1992), the underlying processing pathways must involve different receptor types. The major purpose of this antagonistic organisation is probably to make the visual system most sensitive to spatial or temporal changes, rather than to stationary images.…”

Section: Introductionmentioning

confidence: 99%

“…As ON and OFF responses can be selectively suppressed by drugs (i.e. the glutamate agonist 2‐amino‐4‐phosphoro‐butyrate (APB) blocks the retinal ON channel, another glutamate analogue, 2,3‐piperidine‐dicarboxylic acid (PDA), blocks the OFF channel; Bonaventure et al. , 1992), the underlying processing pathways must involve different receptor types.…”

Section: Introductionmentioning

confidence: 99%

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