γ-Hydroxybutyric Acid and Diazepam Antagonize a Rapid Increase in GABA<sub>A</sub> Receptors α<sub>4</sub> Subunit mRNA Abundance Induced by Ethanol Withdrawal in Cerebellar Granule Cells

Follesa, Paolo; Mancuso, Luisa; Biggio, Francesca; Mostallino, Maria Cristina; Manca, A; Mascia, Maria Paola; Busonero, Fabio; Talani, Giuseppe; Sanna, Enrico; Biggio, Giovanni

doi:10.1124/mol.63.4.896

Cited by 44 publications

(52 citation statements)

References 37 publications

(55 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Altered GABA A R function, characterized by a decreased responsiveness to GABA, a decreased sensitivity to ethanol, cross-tolerance to benzodiazepines and barbiturates, as well as an increased sensitivity to neurosteroids and inverse agonists, is thought to be important in the development of tolerance to and dependence on ethanol (Allan and Harris 1987;Devaud et al 1996;Morrow et al 1988;Sanna et al 1993;Ticku and Burch 1980). Although the molecular mechanisms responsible for the changes in GABA A R function induced by persistent ethanol exposure remain unclear, they have been proposed to involve effects on receptor density (Ticku and Burch 1980), posttranslational modification (Kumar et al 2002), receptor trafficking (Grobin et al 1998), and subunit expression (Devaud et al 1995(Devaud et al , 1997Follesa et al 2003;Mhatre et al 1993;Sanna et al 2003).…”

Section: Effects Of Chronic Ethanol Exposure On Gaba a Rsmentioning

confidence: 96%

“…*P<0.01 vs control; # P<0.01 vs withdrawal. Data are derived from published studies (Sanna et al , copyright 2003 by the Society of Neuroscience, and Follesa et al 2003, with permission of ASPET) Fig. 2 Time-and concentration-dependent stimulatory effect of ethanol on allopregnanolone production in rat hippocampal slices.…”

Section: Effects Of Diazepam Ghb and Baclofen On Gaba A R Plasticitmentioning

confidence: 99%

“…It was then applied together with 3 μM flumazenil or 0.1-0.5 μM zaleplon. Some data are derived from published studies , copyright of the Society for Neuroscience, and Follesa et al 2003, with permission of ASPET) *P<0.05 vs corresponding value for control cells evoke GABA A R-mediated Cl − currents in both types of neuron.…”

Section: Effects Of Chronic Exposure To and Withdrawal Of Ethanol On mentioning

confidence: 99%

See 2 more Smart Citations

Neurosteroids, GABAA receptors, and ethanol dependence

et al. 2005

Self Cite

View full text Add to dashboard Cite

Chronic ethanol exposure elicits changes in the subunit composition of GABAARs, which, in turn, likely contribute to changes in receptor function associated with the altered pharmacological and behavioral sensitivity characteristic of ethanol tolerance and dependence. Ethanol may also modulate GABAAR function by increasing the de novo synthesis of neurosteroids in the brain in a manner independent of the HPA axis. This latter mechanism may play an important role in the central effects of ethanol.

show abstract

Section: Effects Of Chronic Ethanol Exposure On Gaba a Rsmentioning

confidence: 96%

Section: Effects Of Diazepam Ghb and Baclofen On Gaba A R Plasticitmentioning

confidence: 99%

Section: Effects Of Chronic Exposure To and Withdrawal Of Ethanol On mentioning

confidence: 99%

See 1 more Smart Citation

Neurosteroids, GABAA receptors, and ethanol dependence

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…In fact, several studies infer a role for GHB at extrasynaptic GABA A receptors, such as a correlation between elevated GHB levels and increased tonic extrasynaptic inhibition through GABA A receptors (23). More specifically, effects involved receptor subtypes containing α4-and δ-subunits (24)(25)(26).…”

mentioning

confidence: 99%

α4βδ GABA _A receptors are high-affinity targets for γ-hydroxybutyric acid (GHB)

Absalom

Eghorn

Villumsen

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

γ-Hydroxybutyric acid (GHB) binding to brain-specific high-affinity sites is well-established and proposed to explain both physiological and pharmacological actions. However, the mechanistic links between these lines of data are unknown. To identify molecular targets for specific GHB high-affinity binding, we undertook photolinking studies combined with proteomic analyses and identified several GABA A receptor subunits as possible candidates. A subsequent functional screening of various recombinant GABA A receptors in Xenopus laevis oocytes using the two-electrode voltage clamp technique showed GHB to be a partial agonist at αβδ-but not αβγ-receptors, proving that the δ-subunit is essential for potency and efficacy. GHB showed preference for α4 over α(1,2,6)-subunits and preferably activated α4β1δ (EC 50 = 140 nM) over α4β (2/3)δ (EC 50 = 8.41/1.03 mM). Introduction of a mutation, α4F71L, in α4β1(δ)-receptors completely abolished GHB but not GABA function, indicating nonidentical binding sites. Radioligand binding studies using the specific GHB radioligand [ 3 H](E,RS)-(6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylidene)acetic acid showed a 39% reduction (P = 0.0056) in the number of binding sites in α4 KO brain tissue compared with WT controls, corroborating the direct involvement of the α4-subunit in high-affinity GHB binding. Our data link specific GHB forebrain binding sites with α4-containing GABA A receptors and postulate a role for extrasynaptic α4δ-containing GABA A receptors in GHB pharmacology and physiology. This finding will aid in elucidating the molecular mechanisms behind the proposed function of GHB as a neurotransmitter and its unique therapeutic effects in narcolepsy and alcoholism.γ-hydroxybutyric acid receptor | γ-hydroxybutyric acid high-affinity binding sites | α4-subunit knockout | photoaffinity ligand T he GABA metabolite γ-Hydroxybutyric acid (GHB) is present in micromolar concentrations in the mammalian brain, where it has been proposed to act as a neurotransmitter (1). Additionally, GHB is a drug of abuse (Fantasy) and a registered drug for treating narcolepsy (2) and alcoholism (3). GHB binds to at least two distinct populations of low-and high-affinity binding sites in the brain (4). When GHB is ingested in high doses and reaches millimolar concentrations in the brain, it induces behavioral effects such as sedation, motor incoordination and hypothermia (3). These actions are largely mediated by metabotropic GABA B receptors, because effects are prevented by GABA B receptor antagonist pretreatment (5) and completely abolished in GABA B(1)

show abstract

“…Interestingly, the ␥2 chain of GABA A receptor was downregulated by the drug. This could be due to a sustained hyperstimulation because GABA A receptors seem to play a pivotal role in the functional and pharmacological effects of GHB (1,5,10,16,23,63). The majority of GABA A receptors contain a ␥2 subunit, expressed throughout the brain except in the thalamus.…”

Section: Discussionmentioning

confidence: 99%

A single acute pharmacological dose of γ-hydroxybutyrate modifies multiple gene expression patterns in rat hippocampus and frontal cortex

Kemmel¹,

Klein²,

Dembélé

et al. 2010

Physiological Genomics

View full text Add to dashboard Cite

Nyagan AG, Maitre M. A single acute pharmacological dose of ␥-hydroxybutyrate modifies multiple gene expression patterns in rat hippocampus and frontal cortex. Physiol Genomics 41: 146-160, 2010. First published January 26, 2010 doi:10.1152/physiolgenomics.00208.2009.-␥-Hydroxybutyrate (GHB) is a natural brain neuromodulator that has its own enzymatic machinery for synthesis and degradation, release, and transport systems and several receptors that belong to the G protein-coupled receptor (GPCR) family. Targeting of this system with exogenous GHB is used in therapy to induce sleep and anesthesia and to reduce alcohol withdrawal syndrome. GHB is also popular as a recreational drug for its anxiolytic and mild euphoric effects. However, in both cases, GHB must be administered at high doses in order to maintain GHB concentrations in brain of ϳ800 -1,000 M. These high concentrations are thought to be necessary for interactions with lowaffinity sites on GABA B receptor, but the molecular targets and cellular mechanisms modulated by GHB remain poorly characterized. Therefore, to provide new insights into the elucidation of GHB mechanisms of action and open new tracks for future investigations, we explored changes of GHB-induced transcriptomes in rat hippocampus and prefrontal cortex by using DNA microarray studies. We demonstrate that a single acute anesthetic dose of 1 g/kg GHB alters a large number of genes, 121 in hippocampus and 53 in prefrontal cortex; 16 genes were modified simultaneously in both brain regions. In terms of molecular functions, the majority of modified genes coded for proteins or nucleotide binding sites. In terms of Gene Ontology (GO) functional categories, the largest groups were involved in metabolic processing for hippocampal genes and in biological regulation for prefrontal cortex genes. The majority of genes modified in both structures were implicated in cell communication processes. Western blot and immunohistochemical studies carried out on eight selected proteins confirmed the microarray findings.potentiation of brain ␥-aminobutyric acid synapses; sleep and anesthesia; neuroprotection and cell signaling THE IDEA that ␥-hydroxybutyrate (GHB) possesses important functions as a neuromodulator in brain is now supported by numerous results (49). This endogenous compound is synthesized from GABA and is coreleased with it during GABA synaptic activity (51). Endogenous GHB concentrations in brain tissue range from 0.5-1 M to 10-25 M (22) but the fluctuations of GHB in the extracellular spaces, namely in the synapses, have never been measured. Successively, specific GHB binding was described in the brain of several animal species and in humans (6, 13, 31), and more recently GHB receptors have been cloned from both human and rat brain (2, 3). These GHB receptors appear to be heterogeneous with respect to their architecture and pharmacology, despite the fact they belong to G protein-coupled receptor (GPCR) classes. In particular, the GHB analog NCS-382 possesses antagonistic, partial agonist, or no...

show abstract

γ-Hydroxybutyric Acid and Diazepam Antagonize a Rapid Increase in GABA_A Receptors α₄ Subunit mRNA Abundance Induced by Ethanol Withdrawal in Cerebellar Granule Cells

Cited by 44 publications

References 37 publications

Neurosteroids, GABAA receptors, and ethanol dependence

Neurosteroids, GABAA receptors, and ethanol dependence

α4βδ GABA _A receptors are high-affinity targets for γ-hydroxybutyric acid (GHB)

A single acute pharmacological dose of γ-hydroxybutyrate modifies multiple gene expression patterns in rat hippocampus and frontal cortex

Contact Info

Product

Resources

About

γ-Hydroxybutyric Acid and Diazepam Antagonize a Rapid Increase in GABAA Receptors α4 Subunit mRNA Abundance Induced by Ethanol Withdrawal in Cerebellar Granule Cells

Cited by 44 publications

References 37 publications

Neurosteroids, GABAA receptors, and ethanol dependence

Neurosteroids, GABAA receptors, and ethanol dependence

α4βδ GABA A receptors are high-affinity targets for γ-hydroxybutyric acid (GHB)

A single acute pharmacological dose of γ-hydroxybutyrate modifies multiple gene expression patterns in rat hippocampus and frontal cortex

Contact Info

Product

Resources

About

γ-Hydroxybutyric Acid and Diazepam Antagonize a Rapid Increase in GABA_A Receptors α₄ Subunit mRNA Abundance Induced by Ethanol Withdrawal in Cerebellar Granule Cells

α4βδ GABA _A receptors are high-affinity targets for γ-hydroxybutyric acid (GHB)