GABAA receptor subunits in the rat hippocampus I: Immunocytochemical distribution of 13 subunits

Sperk, Günther; Schwarzer, Christoph; Tsunashima, Koichi; Fuchs, Karoline; Sieghart, Werner

doi:10.1016/s0306-4522(97)00146-2

Cited by 303 publications

(306 citation statements)

References 43 publications

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“…The cellular distribution of the α1 subunit in the dentate gyrus was similar to that described in detail in the past [8,10,16,29,32]. The distribution of the γ2 subunit was similar to that of the α1 subunit and it is possible that the two antibodies detected similar sets of GABA A receptors on granule cells.…”

Section: Subcellular Distribution Of α1 and γ2 Subunitssupporting

confidence: 79%

“…The antibody against α4 subunit (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) has been characterized previously [1,12,32]. The antibodies against the γ2 (1-33) and δ (1-44) subunit of the GABA A receptor have been characterized extensively in the past by immunoprecipitation, Western blot, and immunohistochemistry [11,[19][20][21][22]32]. The antibodies against α1, α4, γ2 and δ were characterized by Western blot.…”

Section: Antibodiesmentioning

confidence: 99%

“…In addition to cerebellar granule cells, dentate granule cells in the hippocampus also express the δ subunit mRNA and polypeptide [3,32]. The α6 subunit is not expressed in these neurons and the δ subunit is believed to combine with the α4 subunit to form functional receptors [34].…”

Section: Introductionmentioning

confidence: 99%

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Distribution of α1, α4, γ2, and δ subunits of GABAA receptors in hippocampal granule cells

2004

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GABA A receptors are pentamers composed of subunits derived from the α, β, γ, δ, θ, ε, and π gene families. α1, α4, γ2, and δ subunits are expressed in the dentate gyrus of the hippocampus, but their subcellular distribution has not been described. Hippocampal sections were double-labeled for the α1, α4, γ2, and δ subunits and GAD65 or gephyrin, and their subcellular distribution on dentate granule cells was studied by means of confocal laser scanning microscopy (CLSM). The synaptic versus extrasynaptic localization of these subunits was inferred by quantitative analysis of the frequency of colocalization of various subunits with synaptic markers in high-resolution images. GAD65 immunoreactive clusters colocalized with 26.24±0.86% of the α1 subunit immunoreactive clusters and 32.35±1.49% of the γ2 subunit clusters. In contrast, only 1.58±0.13% of the α4 subunit immunoreactive clusters and 1.92±0.15% of the δ subunit clusters colocalized with the presynaptic marker GAD65. These findings were confirmed by studying colocalization with immunoreactivity of a postsynaptic marker, gephyrin, which colocalized with 27.61±0.16% of the α1 subunit immunoreactive clusters and 23.45±0.32% of the γ2 subunit immunoreactive clusters. In contrast, only 1.90±0.13% of the α4 subunit immunoreactive clusters and 1.76±0.10% of the δ subunit clusters colocalized with gephyrin. These studies demonstrate that a subset of α1 and γ2 subunit clusters colocalize with synaptic markers in hippocampal dentate granule cells. Furthermore, all four subunits, α1, α4, γ2, and δ, are present in the extrasynaptic locations.

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Section: Subcellular Distribution Of α1 and γ2 Subunitssupporting

confidence: 79%

Section: Antibodiesmentioning

confidence: 99%

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Distribution of α1, α4, γ2, and δ subunits of GABAA receptors in hippocampal granule cells

2004

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“…The aforementioned data demonstrate that this isoform heterogeneity in individual hippocampal neurons is also observed at the protein level. It is also worth mentioning that with the exception of ␣ 3 , the other studied subunits are highly expressed in the intact hippocampus (Fritschy and Möhler, 1995;Sperk et al, 1997;Miralles et al, 1999;Christie et al, 2002). However, in the intact hippocampus, the ␣ 3 subunit is expressed at very low levels, as shown with various antibodies, including the one used in the present study.…”

Section: Individual Hippocampal Pyramidal Cells and Interneurons In Cmentioning

confidence: 46%

GABAergic Innervation Organizes Synaptic and Extrasynaptic GABA_AReceptor Clustering in Cultured Hippocampal Neurons

2002

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We have studied the effects of GABAergic innervation on the clustering of GABA A receptors (GABA A Rs) in cultured hippocampal neurons. In the absence of GABAergic innervation, pyramidal cells form small (0.36 Ϯ 0.01 m diameter) GABA A R clusters at their surface in the dendrites and soma. When receiving GABAergic innervation from glutamic acid decarboxylase-containing interneurons, pyramidal cells form large (1.62 Ϯ 0.08 m breadth) GABA A R clusters at GABAergic synapses. This is accompanied by a disappearance of the small GABA A R clusters in the local area surrounding each GABAergic synapse. Although the large synaptic GABA A R clusters of any neuron contained all GABA A R subunits and isoforms expressed by that neuron, the small clusters not localized at GABAergic synapses showed significant heterogeneity in subunit and isoform composition. Another difference between large GABAergic and small non-GABAergic GABA A R clusters was that a significant proportion of the latter was juxtaposed to postsynaptic markers of glutamatergic synapses such as PSD-95 and AMPA receptor GluR1 subunit. The densities of both the glutamate receptor-associated and non-associated small GABA A R clusters were decreased in areas surrounding GABAergic synapses. However, no effect on the density or distribution of glutamate receptor clusters was observed. The results suggest that there are local signals generated at GABAergic synapses that induce both assembly of large synaptic GABA A R clusters at the synapse and disappearance of the small GABA A R clusters in the surrounding area. In the absence of GABAergic innervation, weaker GABA A R-clustering signals, generated at glutamatergic synapses, induce the formation of small postsynaptic GABA A R clusters that remain juxtaposed to glutamate receptors at glutamatergic synapses.

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“…and rabbit polyclonal antibodies specific for ␣1 (1-9 residues), ␣4 (379 -421 residues), ␣5 (2-10 residues), ␤1 (350 -404 residues), ␤2 (351-405 residues), ␤3 (345-408 residues), ␥1 (324 -366 residues), ␥2 (319 -366 residues), and ␥3 (322-372 residues) subunits (generated by W.S.). The characterization and specificity of these antibodies have been described in detail elsewhere (Benke et al, 1991(Benke et al, , 1997Buchstaller et al, 1991;Marksitzer et al, 1993;Mertens et al, 1993;Mossier et al, 1994;Todd et al, 1996;Sperk et al, 1997). The cells were immunoreacted with guinea pig antibodies diluted 1:1000 or rabbit antibodies diluted 1:100 -300 overnight at room temperature.…”

Section: Immunoc Ytochemistr Ymentioning

confidence: 99%

GABA_AReceptor Subunit Composition and Functional Properties of Cl⁻Channels with Differential Sensitivity to Zolpidem in Embryonic Rat Hippocampal Cells

et al. 1999

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Using flow cytometry in conjunction with a voltage-sensitive fluorescent indicator dye (oxonol), we have identified and separated embryonic hippocampal cells according to the sensitivity of their functionally expressed GABA A receptors to zolpidem. Immunocytochemical and RT-PCR analysis of sorted zolpidem-sensitive (ZS) and zolpidem-insensitive (ZI) subpopulations identified ZS cells as postmitotic, differentiating neurons expressing ␣2, ␣4, ␣5, ␤1, ␤2, ␤3, ␥1, ␥2, and ␥3 GABA A receptor subunits, whereas the ZI cells were neuroepithelial cells or newly postmitotic neurons, expressing predominantly ␣4, ␣5, ␤1, and ␥2 subunits. Fluctuation analyses of macroscopic Cl Ϫ currents evoked by GABA revealed three kinetic components of GABA A receptor/Cl Ϫ channel activity in both subpopulations. We focused our study on ZI cells, which exhibited a limited number of subunits and functional channels, to directly correlate subunit composition with channel properties. Biophysical analyses of GABA-activated Cl Ϫ currents in ZI cells revealed two types of receptor-coupled channel properties: one comprising short-lasting openings, high affinity for GABA, and low sensitivity to diazepam, and the other with long-lasting openings, low affinity for GABA, and high sensitivity to diazepam. Both types of channel activity were found in the same cell. Channel kinetics were well modeled by fitting dwell time distributions to biliganded activation and included two open and five closed states. We propose that short-and long-lasting openings correspond to GABA A receptor/Cl Ϫ channels containing ␣4␤1␥2 and ␣5␤1␥2 subunits, respectively.

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GABAA receptor subunits in the rat hippocampus I: Immunocytochemical distribution of 13 subunits

Cited by 303 publications

References 43 publications

Distribution of α1, α4, γ2, and δ subunits of GABAA receptors in hippocampal granule cells

Distribution of α1, α4, γ2, and δ subunits of GABAA receptors in hippocampal granule cells

GABAergic Innervation Organizes Synaptic and Extrasynaptic GABA_AReceptor Clustering in Cultured Hippocampal Neurons

GABA_AReceptor Subunit Composition and Functional Properties of Cl⁻Channels with Differential Sensitivity to Zolpidem in Embryonic Rat Hippocampal Cells

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GABAA receptor subunits in the rat hippocampus I: Immunocytochemical distribution of 13 subunits

Cited by 303 publications

References 43 publications

Distribution of α1, α4, γ2, and δ subunits of GABAA receptors in hippocampal granule cells

Distribution of α1, α4, γ2, and δ subunits of GABAA receptors in hippocampal granule cells

GABAergic Innervation Organizes Synaptic and Extrasynaptic GABAAReceptor Clustering in Cultured Hippocampal Neurons

GABAAReceptor Subunit Composition and Functional Properties of Cl−Channels with Differential Sensitivity to Zolpidem in Embryonic Rat Hippocampal Cells

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GABAergic Innervation Organizes Synaptic and Extrasynaptic GABA_AReceptor Clustering in Cultured Hippocampal Neurons

GABA_AReceptor Subunit Composition and Functional Properties of Cl⁻Channels with Differential Sensitivity to Zolpidem in Embryonic Rat Hippocampal Cells