| The effects of zolpidem treatment and withdrawal on the in vitro expression of recombinant alpha1beta2gamma2s GABA(A) receptors expressed in HEK 293 cells. | |
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MedLine Citation:
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PMID: 20652804 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Zolpidem, a widely used hypnotic drug which acts through benzodiazepine binding sites, is a positive allosteric modulator of gamma-aminobutyric acid (GABA) action with preferential affinity for GABA(A) receptors containing alpha1 subunit. The pharmacological profile of zolpidem is different from that of classical benzodiazepines. The aim of this study was to find out whether zolpidem treatment triggers adaptive changes in the recombinant alpha1 subunit-containing GABA(A) receptors other than those observed following treatment with classical benzodiazepine-diazepam. Radioligand binding studies showed that 2-day exposure of human embryonic kidney (HEK) 293 cells stably expressing recombinant alpha1beta2gamma2s GABA(A) receptors to zolpidem (10 muM) up-regulated the maximum number (B (max)) of [(3)H]flunitrazepam, [(3)H]muscimol, and [(3)H]t-butylbicycloorthobenzoate ([(3)H]TBOB) binding sites without changing their affinity (K (d)), suggesting an increase in total GABA(A) receptor number. Semi-quantitative RT-PCR analysis demonstrated increased levels of alpha1 subunit mRNA, while Western blot demonstrated up-regulated gamma2 subunit proteins, suggesting that zolpidem induced de novo synthesis of receptors proteins, at both the transcriptional and translational levels. GABA-induced potentiation of [(3)H]flunitrazepam binding to membranes obtained from zolpidem-treated cells was markedly reduced, indicating allosteric uncoupling between GABA and benzodiazepine binding sites. The number of benzodiazepine and convulsant binding sites as well as the functional coupling between GABA and benzodiazepine binding sites normalized in 24 h following discontinuation of zolpidem treatment. The results of our in vitro studies suggest that a 2-day exposure of recombinant alpha1 subunit-containing GABA(A) receptors stably transfected in HEK 293 cells to zolpidem induces adaptive changes in this selective GABA(A) receptor subtype, which are not substantially different from those obtained after prolonged exposure of cells to high concentrations of diazepam. |
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Authors:
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Josipa Vlainić; Maja Jazvinsćak Jembrek; Dubravka Svob Strac; Danka Pericić |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't Date: 2010-07-23 |
Journal Detail:
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Title: Naunyn-Schmiedeberg's archives of pharmacology Volume: 382 ISSN: 1432-1912 ISO Abbreviation: Naunyn Schmiedebergs Arch. Pharmacol. Publication Date: 2010 Sep |
Date Detail:
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Created Date: 2010-08-24 Completed Date: 2010-12-02 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0326264 Medline TA: Naunyn Schmiedebergs Arch Pharmacol Country: Germany |
Other Details:
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Languages: eng Pagination: 201-12 Citation Subset: IM |
Affiliation:
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Division of Molecular Medicine, Ruder Bosković Institute, Zagreb, Croatia. josipa.vlainic@irb.hr |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Binding Sites Blotting, Western Cell Line Diazepam / pharmacology Flunitrazepam / metabolism Humans Hypnotics and Sedatives / pharmacology Kidney / cytology, drug effects, metabolism Protein Binding Pyridines / pharmacology* RNA, Messenger / metabolism Rats Receptors, GABA-A / drug effects*, genetics Reverse Transcriptase Polymerase Chain Reaction Substance Withdrawal Syndrome / metabolism* Transfection Up-Regulation / drug effects* |
| Chemical | |
Reg. No./Substance:
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0/Hypnotics and Sedatives; 0/Pyridines; 0/RNA, Messenger; 0/Receptors, GABA-A; 1622-62-4/Flunitrazepam; 439-14-5/Diazepam; 82626-48-0/zolpidem |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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