Synaptic and Nonsynaptic Localization of Benzodiazepine/GABA<sub>A</sub> Receptor/Cl<sup>−</sup> Channel Complex Using Monoclonal Antibodies in the Dorsal Lateral Geniculate Nucleus of the Cat

Soltész, Iván; Roberts, J. D. B.; Takagi, Hidenari; Richards, J. G.; Möhler, Hanns; Somogyi, Péter

doi:10.1111/j.1460-9568.1990.tb00434.x

Cited by 64 publications

(50 citation statements)

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“…Mice were housed under controlled conditions at 19Ϫ23°C, on a 12 h alternating light/dark cycle, in a ventilated room with access to food and water ad libitum. Mice homozygous for the Y365/367F mutation do not survive in utero, but heterozygotes continue into adulthood (Tretter et al, 2009). GABA A R ␥2 Y365/367F heterozygous knock-in (Y365/367F ϩ/Ϫ) mice and littermate controls were maintained on a C57BL/6J genetic background and had been backcrossed at least nine times.…”

Section: Methodsmentioning

confidence: 99%

“…In principle, this substitution should prevent receptor internalization and therefore potentiate phasic inhibition (Kittler et al, 2008;Tretter et al, 2009), but the consequences for tonic inhibition are unknown.…”

Section: Sex-specific Effect Of ␥2mentioning

confidence: 99%

“…The ␣4-subunit was selected because of its involvement in extrasynaptic receptors and tonic inhibition in the dentate gyrus (DG) as well as specific thalamic nuclei (Cope et al, 2005;Chandra et al, 2006;Bright et al, 2007;Shen et al, 2007). We compared ␣4-subunit expression levels in the brains of age-matched Y365/ 367F heterozygotes (HT) and WT littermates (homozygotes are not viable in utero; Tretter et al, 2009). While in the HT males ␣4-subunit expression was reduced in the DG (55.4 Ϯ 6.4%, n ϭ 5, p Ͻ 0.01) and thalamus (62.5 Ϯ 9.2%, n ϭ 5, p Ͻ 0.01) compared with WT (100%; Fig.…”

Section: Sex-specific Effect Of ␥2mentioning

confidence: 99%

“…Previously we noted that the Y365/367F homozygote is lethal and that male heterozygotes exhibited enhanced accumulation of synaptic GABA A Rs in the hippocampal CA3 region due to aberrant trafficking within the endocytic pathway. This enhanced inhibition correlated with a specific deficit in spatial object recognition, a behavioral trait that is associated with regio CA3 (Tretter et al, 2009). Here, we used this animal model to assess whether the tyrosine mutations affected the expression of ␣4-and ␦-subunits, both critical components of extrasynaptic GABA A Rs mediating tonic inhibition in several areas of the forebrain (Cope et al, 2005;Chandra et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…In the dLGN, ␣1␤␥2 GABA A Rs are mainly responsible for phasic inhibition (Soltesz et al, 1990;Okada et al, 2000), while tonic inhibition depends on ␣4␤␦ receptors (Cope et al, 2005;Bright et al, 2007). Using patch-clamp recording, immunocytochemistry, and immunoblotting, we found that Y365/367F enhanced both phasic and tonic inhibition in female animals only.…”

Section: Introductionmentioning

confidence: 99%

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Tyrosine Phosphorylation of GABAA Receptor 2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

Nani

Bright

Revilla-Sanchez

et al. 2013

Journal of Neuroscience

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GABA-mediated tonic and phasic inhibition of thalamic relay neurons of the dorsal lateral geniculate nucleus (dLGN) was studied after ablating tyrosine (Y) phosphorylation of receptor ␥2-subunits. As phosphorylation of ␥2 Y365 and Y367 reduces receptor internalization, to understand their importance for inhibition we created a knock-in mouse in which these residues are replaced by phenylalanines. On comparing wild-type (WT) and ␥2 Y365/367F ϩ/Ϫ (HT) animals (homozygotes are not viable in utero), the expression levels of GABA A receptor ␣4-subunits were increased in the thalamus of female, but not male mice. Raised ␦-subunit expression levels were also observed in female ␥2 Y365/367F ϩ/Ϫ thalamus. Electrophysiological analyses revealed no difference in the level of inhibition in male WT and HT dLGN, while both the spontaneous inhibitory postsynaptic activity and the tonic current were significantly augmented in female HT relay cells. The sensitivity of tonic currents to the ␦-subunit superagonist THIP, and the blocker Zn 2ϩ , were higher in female HT relay cells. This is consistent with upregulation of extrasynaptic GABA A receptors containing ␣4-and ␦-subunits to enhance tonic inhibition. In contrast, the sensitivity of GABA A receptors mediating inhibition in the female ␥2 Y356/367F ϩ/Ϫ to neurosteroids was markedly reduced compared with WT. We conclude that disrupting tyrosine phosphorylation of the ␥2-subunit activates a sex-specific increase in tonic inhibition, and this most likely reflects a genomic-based compensation mechanism for the reduced neurosteroid sensitivity of inhibition measured in female HT relay neurons.

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Section: Methodsmentioning

confidence: 99%

Section: Sex-specific Effect Of ␥2mentioning

confidence: 99%

Section: Sex-specific Effect Of ␥2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tyrosine Phosphorylation of GABAA Receptor 2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

Nani

Bright

Revilla-Sanchez

et al. 2013

Journal of Neuroscience

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Distribution of immunoreactivity for the β ₂ and β ₃ subunits of the GABA _A receptor in the mammalian spinal cord

et al. 1996

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The localization of GABAA receptors in cat and rat spinal cord was analyzed using two monoclonal antibodies specific for an epitope shared by the beta 2 and beta 3 subunits of the receptor. beta 2/beta 3-subunit immunoreactivity was the most intense in inner lamina II, lamina III, and lamina X, and it was the least intense in lamina IX. In laminae I-III, generally, the staining had a rather diffuse appearance, but the surfaces of small cell bodies in these laminae were outlined clearly by discrete labeling, as were many cell bodies and dendrites in deeper laminae. Rhizotomy experiments and ultrastructural observations indicated that beta 2/beta 3-subunit immunoreactivity in the dorsal horn was largely localized in intrinsic neuropil elements rather than in the terminals of primary afferent fibers, even though labeling overlapped with the terminal fields of different types of primary afferents and was also detected on the membranes of dorsal root ganglion neurons. With few exceptions (most notably, a highly immunoreactive group of dorsolaterally located cells in the cat lumbar ventral horn), motoneurons expressed low levels of beta 2/beta 3-subunit immunoreactivity. Labeling of neuronal membranes was fairly continuous, but focal accumulations of beta 2/beta 3-subunit immunoreactivity were also detected using immunofluorescence. Focal "hot spots" correlated ultrastructurally with the presence of synaptic junctions. Dual-color immunofluorescence revealed that focal accumulations of beta 2/beta 3-subunit immunoreactivity were frequently apposed by glutamic acid decarboxylase (GAD)-immunoreactive terminals. However, the density of continuous-membrane beta 2/beta 3 immunolabeling and GAD terminal density were not correlated in many individual neurons. The results suggest the existence of "classical" (synaptic) and "nonclassical" (paracrine) actions mediated via spinal cord GABAA receptors. The study also revealed the relative paucity of beta 2/beta 3-subunit immunoreactivity postsynaptic to certain GABAergic terminals, particularly those presynaptic to motoneurons or primary afferent terminals.

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Synaptogenesis in the rat retina: subcellular localization of glycine receptors, GABAA receptors, and the anchoring protein gephyrin

Sassoè‐Pognetto

Wässle

1997

J. Comp. Neurol.

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The mechanisms by which neurotransmitter receptors are clustered at postsynaptic sites of neurons are largely unknown. The 93-kDa peripheral membrane protein gephyrin has been shown to be essential for the formation of postsynaptic glycine receptor clusters, and there is now evidence that gephyrin can also be found at gamma-aminobutyric acid (GABA)ergic synapses. In this study, we have analyzed the synaptic localization of glycine receptors, GABA(A) receptors, and the anchoring protein gephyrin in the inner plexiform layer of the developing rat retina, by using immunofluorescence with subunit specific antibodies. At early postnatal stages, the antibodies produced a diffuse staining, suggesting that early retinal neurons can express glycine and GABA(A) receptors. A clustered distribution of the subunits in "hot spots" was also observed. The number of "hot spots" increased during development and reached adult levels in about 2 weeks. Electron microscopy showed that synapses of the conventional type are present in the inner plexiform layer of the postnatal retina and that the hot spots correspond to an aggregation of receptors at postsynaptic sites. Gephyrin was also localized to "hot spots," and double immunofluorescence revealed a colocalization of gephyrin with the alpha2 subunit of the GABA(A) receptor. These results indicate that clustering of receptor subunits occurs in parallel with the formation of morphologically identifiable synaptic specializations and suggest that gephyrin may be involved in clustering of GABA(A) receptors at postsynaptic sites.

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Synaptic and Nonsynaptic Localization of Benzodiazepine/GABA_A Receptor/Cl⁻ Channel Complex Using Monoclonal Antibodies in the Dorsal Lateral Geniculate Nucleus of the Cat

Cited by 64 publications

References 75 publications

Tyrosine Phosphorylation of GABAA Receptor 2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

Tyrosine Phosphorylation of GABAA Receptor 2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

Distribution of immunoreactivity for the β ₂ and β ₃ subunits of the GABA _A receptor in the mammalian spinal cord

Synaptogenesis in the rat retina: subcellular localization of glycine receptors, GABAA receptors, and the anchoring protein gephyrin

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Synaptic and Nonsynaptic Localization of Benzodiazepine/GABAA Receptor/Cl− Channel Complex Using Monoclonal Antibodies in the Dorsal Lateral Geniculate Nucleus of the Cat

Cited by 64 publications

References 75 publications

Tyrosine Phosphorylation of GABAA Receptor 2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

Tyrosine Phosphorylation of GABAA Receptor 2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

Distribution of immunoreactivity for the β 2 and β 3 subunits of the GABA A receptor in the mammalian spinal cord

Synaptogenesis in the rat retina: subcellular localization of glycine receptors, GABAA receptors, and the anchoring protein gephyrin

Contact Info

Product

Resources

About

Synaptic and Nonsynaptic Localization of Benzodiazepine/GABA_A Receptor/Cl⁻ Channel Complex Using Monoclonal Antibodies in the Dorsal Lateral Geniculate Nucleus of the Cat

Distribution of immunoreactivity for the β ₂ and β ₃ subunits of the GABA _A receptor in the mammalian spinal cord