Glycine receptor immunoreactivity is localized at amacrine synapses in cat retina

Pourcho, Roberta G.; Owczarzak, Michael T.

doi:10.1017/s0952523800010397

Cited by 49 publications

(68 citation statements)

References 33 publications

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“…3A). Punctate distribution of the mGluR5a receptor staining at the light microscopic level indicated synaptic localization, as was shown for several other types of neurotransmitter receptors in the retina (Pourcho and Owczarzak, 1991;Yazulla and Studholme, 1991;Grünert and Wässle, 1993;Hartveit et al, 1994;Brandstätter et al, 1996). The diffuse labeling on putative bipolar cell somata in the INL, however, also showed extrasynaptic localization of mGluR5a immunolabel.…”

Section: Distribution Of Mglur5a In the Adult Rat Retinasupporting

confidence: 70%

Group I Metabotropic Glutamate Receptors mGluR1α and mGluR5a: Localization in Both Synaptic Layers of the Rat Retina

et al. 1997

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We examined the distribution of the group I metabotropic glutamate receptors, mGluR1␣ and mGluR5a, in the adult rat retina and during postnatal development using receptorspecific antisera. In contrast to the restricted localization of group II and group III mGluRs to either the outer plexiform layer (OPL) or the inner plexiform layer (IPL), group I mGluRs are present in both synaptic layers in the rat retina. Double-labeling experiments and electron microscopy showed that in the OPL the two receptors are localized on the dendritic tips of bipolar cells postsynaptic to photoreceptor terminals. In the IPL the two mGluRs are localized on amacrine cell processes postsynaptic to bipolar cell terminals. These results suggest that group I mGluRs are involved in synaptic processing in both plexiform layers and in both the scotopic and photopic pathways in the rat retina. We propose that mGluR1␣ and mGluR5a play an important modulatory role in the responses of retinal neurons to inhibitory and excitatory neurotransmitters.

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Section: Distribution Of Mglur5a In the Adult Rat Retinasupporting

confidence: 70%

Group I Metabotropic Glutamate Receptors mGluR1α and mGluR5a: Localization in Both Synaptic Layers of the Rat Retina

et al. 1997

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“…However, these receptors appeared to have their lowest density in the axonal region where synapses occur with glycinergic amacrine cells. Even more puzzling has been the failure to detect glycine receptors at glycinergic synapses with bipolar cells (Poucho & Owczarzak, 1991;Griunert & Wiissle, 1993). These findings do not support the scheme in Fig.…”

Section: Resultsmentioning

confidence: 99%

Baclofen enhancement of acetylcholine release from amacrine cells in the rabbit retina by reduction of glycinergic inhibition.

Neal

Cunningham

1995

The Journal of Physiology

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1. The mechanism by which the GABAB-receptor agonist, baclofen, enhances the lightevoked release of [3H]acetylcholine (ACh) from cholinergic amacrine cells was studied using an eye-cup preparation in anaesthetized rabbits and isolated retinas.2. WVhen applied locally to the rabbit retina, baclofen increased the release of ACh evoked by a ffickering light (3 Hz) by over 40 %. 3. In isolated retinas, baclofen strikingly inhibited the K+-evoked release of glycine but had no effect on GABA release. 4. In the rabbit eye cup, strychnine enhanced the light-evoked release of ACh to a similar degree to that produced by baclofen. The effects of baclofen and strychnine on the lightevoked release of ACh were not additive. In contrast, bicuculline did not affect the enhancing action of baclofen on the light-evoked release of ACh. 5. In order to see whether the glycinergic amacrine cells might be stimulated by ACh, isolated rat and rabbit retinas were exposed to muscarine. This cholinergic agonist potentiated the K+-evoked release of glycine by 54 %.6. We suggest that baclofen enhances the light-evoked release of ACh from amacrine cells by inhibiting glycine release from glycinergic amacrine cells which are stimulated by ACh and form an inhibitory feedback loop to the cholinergic neurones.

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“…Glutamic acid decarboxylase (GAD), the GABA-synthesizing enzyme, was found immunocytochemically (Mosinger and Yazulla, 1987;Brecha et al, 1988) and by in situ hybridization with GAD mRNA in amacrine cells (Sarthy and Fu, 1989). Glycine accumulates in other amacrine cells of mammalian retinas (Marc and Liu, 1985), where it also was detected immunocytochemically (Hendrickson et al, 1988;Davenger et al, 1991;Pourcho and Owarczak, 1991;Koontz et al, 1993). GABA A receptor subunits have been localized in RGCs and in the inner plexiform layer, possibly at RGC dendrites (Hughes et al, 1989(Hughes et al, , 1991Greferath et al, 1994a;Koulen et al, 1996).…”

Section: Abstract: Synaptic Currents; Gaba; Glycine; Retina; Patchclmentioning

confidence: 99%

“…GABA A receptor subunits have been localized in RGCs and in the inner plexiform layer, possibly at RGC dendrites (Hughes et al, 1989(Hughes et al, , 1991Greferath et al, 1994a;Koulen et al, 1996). Glycine receptor subunits also have been found at similar sites (Pourcho and Owarczak, 1991;Greferath et al, 1994b). Moreover, receptors to both transmitters are segregated spatially in clusters on the somatodendritic membranes of rat RGCs (Koulen et al, 1996).…”

Section: Abstract: Synaptic Currents; Gaba; Glycine; Retina; Patchclmentioning

confidence: 99%

GABAergic and glycinergic IPSCs in Ganglion Cells of Rat Retinal Slices

1997

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GABAergic and glycinergic IPSCs were studied in identified retinal ganglion cells (RGCs) of light-adapted rat retinal slices, using whole-cell recording techniques. GABAergic IPSCs were blocked specifically by SR95531 (3 M) and bicuculline (3 M) and glycinergic IPSCs by strychnine (0.3 M). From 37 RGCs studied, 25 showed exclusively GABAergic IPSCs, 6 presented only glycinergic IPSCs, and 6 showed both. This distribution may result from differences in amacrine cells input rather than from receptor heterogeneity, because both GABA and glycine elicited Cl Ϫ -selective currents in all RGCs tested. TTX markedly reduced GABAergic IPSCs frequency, whereas glycinergic IPSCs were unaffected. Ca 2ϩ -free media, with or without high Mg 2ϩ , blocked TTX-resistant GABAergic and glycinergic IPSCs. These results suggest that GABAergic IPSCs in RGCs can be elicited either by Na ϩ -dependent action potentials or by local Ca 2ϩ influx in medium or large dendritic field GABAergic amacrine cells, whereas glycinergic IPSCs are generated by action potential-independent Ca 2ϩ influx in narrow field glycinergic amacrine cells. Both types of IPSCs had fast rise times and biexponential decays, but glycinergic IPSC decay was significantly slower than that of GABAergic IPSCs. An elementary conductance of 54 pS for the glycine-gated channels was estimated from single-channel events, clearly detected in the falling phase of glycinergic IPSCs, and from responses to exogenous glycine.

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Glycine receptor immunoreactivity is localized at amacrine synapses in cat retina

Cited by 49 publications

References 33 publications

Group I Metabotropic Glutamate Receptors mGluR1α and mGluR5a: Localization in Both Synaptic Layers of the Rat Retina

Group I Metabotropic Glutamate Receptors mGluR1α and mGluR5a: Localization in Both Synaptic Layers of the Rat Retina

Baclofen enhancement of acetylcholine release from amacrine cells in the rabbit retina by reduction of glycinergic inhibition.

GABAergic and glycinergic IPSCs in Ganglion Cells of Rat Retinal Slices

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