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Solomon VR, Tallapragada VJ, Chebib M, Johnston G, Hanrahan JR. GABA allosteric modulators: An overview of recent developments in non-benzodiazepine modulators. Eur J Med Chem 2019; 171:434-461. [DOI: 10.1016/j.ejmech.2019.03.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/17/2019] [Accepted: 03/17/2019] [Indexed: 01/13/2023]
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High-throughput Screening in Larval Zebrafish Identifies Novel Potent Sedative-hypnotics. Anesthesiology 2019; 129:459-476. [PMID: 29894316 DOI: 10.1097/aln.0000000000002281] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Many general anesthetics were discovered empirically, but primary screens to find new sedative-hypnotics in drug libraries have not used animals, limiting the types of drugs discovered. The authors hypothesized that a sedative-hypnotic screening approach using zebrafish larvae responses to sensory stimuli would perform comparably to standard assays, and efficiently identify new active compounds. METHODS The authors developed a binary outcome photomotor response assay for zebrafish larvae using a computerized system that tracked individual motions of up to 96 animals simultaneously. The assay was validated against tadpole loss of righting reflexes, using sedative-hypnotics of widely varying potencies that affect various molecular targets. A total of 374 representative compounds from a larger library were screened in zebrafish larvae for hypnotic activity at 10 µM. Molecular mechanisms of hits were explored in anesthetic-sensitive ion channels using electrophysiology, or in zebrafish using a specific reversal agent. RESULTS Zebrafish larvae assays required far less drug, time, and effort than tadpoles. In validation experiments, zebrafish and tadpole screening for hypnotic activity agreed 100% (n = 11; P = 0.002), and potencies were very similar (Pearson correlation, r > 0.999). Two reversible and potent sedative-hypnotics were discovered in the library subset. CMLD003237 (EC50, ~11 µM) weakly modulated γ-aminobutyric acid type A receptors and inhibited neuronal nicotinic receptors. CMLD006025 (EC50, ~13 µM) inhibited both N-methyl-D-aspartate and neuronal nicotinic receptors. CONCLUSIONS Photomotor response assays in zebrafish larvae are a mechanism-independent platform for high-throughput screening to identify novel sedative-hypnotics. The variety of chemotypes producing hypnosis is likely much larger than currently known.
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Stadler M, Monticelli S, Seidel T, Luger D, Salzer I, Boehm S, Holzer W, Schwarzer C, Urban E, Khom S, Langer T, Pace V, Hering S. Design, Synthesis, and Pharmacological Evaluation of Novel β2/3 Subunit-Selective γ-Aminobutyric Acid Type A (GABA A) Receptor Modulators. J Med Chem 2018; 62:317-341. [PMID: 30289721 DOI: 10.1021/acs.jmedchem.8b00859] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Subunit-selective modulation of γ-aminobutyric acid type A receptors (GABAAR) is considered to exert fewer side effects compared to unselective clinically used drugs. Here, the β2/3 subunit-selective GABAAR modulators valerenic acid (VA) and loreclezole (LOR) guided the synthesis of novel subunit-selective ligands with simplified structures. We studied their effects on GABAARs expressed in Xenopus laevis oocytes using two-microelectrode voltage clamp technique. Five compounds showed significantly more efficacious modulation of GABA-evoked currents than VA and LOR with retained potency and selectivity. Compound 18 [( E)-2-Cyano-3-(2,4-dichlorophenyl)but-2-enamide] induced the highest maximal modulation of GABA-induced chloride currents ( Emax: 3114 ± 242%), while 12 [( Z)-3-(2,4-dichlorophenyl)but-2-enenitrile] displayed the highest potency (EC50: 13 ± 2 μM). Furthermore, in hippocampal neurons 12 facilitated phasic and tonic GABAergic inhibition, and in vivo studies revealed significantly more potent protection against pentylenetetrazole (PTZ)-induced seizures compared to VA and LOR. Collectively, compound 12 constitutes a novel, simplified, and subunit-selective GABAAR modulator with low-dose anticonvulsant activity.
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Affiliation(s)
- Marco Stadler
- Department of Pharmacology and Toxicology , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Serena Monticelli
- Department of Pharmaceutical Chemistry , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Thomas Seidel
- Department of Pharmaceutical Chemistry , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Denise Luger
- Department of Pharmacology and Toxicology , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Isabella Salzer
- Department of Neurophysiology and Neuropharmacology , Medical University Vienna , Schwarzspanierstraße 17 , 1090 Vienna , Austria
| | - Stefan Boehm
- Department of Neurophysiology and Neuropharmacology , Medical University Vienna , Schwarzspanierstraße 17 , 1090 Vienna , Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Christoph Schwarzer
- Department of Pharmacology , Medical University Innsbruck , Peter-Mayr-Straße 1a , 6020 Innsbruck , Austria
| | - Ernst Urban
- Department of Pharmaceutical Chemistry , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Sophia Khom
- Department of Pharmacology and Toxicology , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria.,Department of Neuroscience , The Scripps Research Institute , 10550 N Torrey Pines Road , La Jolla , California 92037 , United States
| | - Thierry Langer
- Department of Pharmaceutical Chemistry , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Vittorio Pace
- Department of Pharmaceutical Chemistry , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
| | - Steffen Hering
- Department of Pharmacology and Toxicology , University of Vienna , Althanstraße 14 , 1090 Vienna , Austria
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Milanos S, Kuenzel K, Gilbert DF, Janzen D, Sasi M, Buettner A, Frimurer TM, Villmann C. Structural changes at the myrtenol backbone reverse its positive allosteric potential into inhibitory GABAA receptor modulation. Biol Chem 2018; 399:549-563. [DOI: 10.1515/hsz-2017-0262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/24/2018] [Indexed: 02/07/2023]
Abstract
Abstract
GABAA receptors are ligand-gated anion channels that form pentameric arrangements of various subunits. Positive allosteric modulators of GABAA receptors have been reported as being isolated either from plants or synthesized analogs of known GABAA receptor targeting drugs. Recently, we identified monoterpenes, e.g. myrtenol as a positive allosteric modulator at α1β2 GABAA receptors. Here, along with pharmacophore-based virtual screening studies, we demonstrate that scaffold modifications of myrtenol resulted in the loss of modulatory activity. Two independent approaches, fluorescence-based compound analysis and electrophysiological recordings in whole-cell configurations were used for analysis of transfected cells. C-atoms 1 and 2 of the myrtenol backbone were identified as crucial to preserve positive allosteric potential. A modification at C-atom 2 and lack of the hydroxyl group at C-atom 1 exhibited significantly reduced GABAergic currents at α1β2, α1β2γ, α2β3, α2β3γ and α4β3δ receptors. This effect was independent of the γ2 subunit. A sub-screen with side chain length and volume differences at the C-atom 1 identified two compounds that inhibited GABAergic responses but without receptor subtype specificity. Our combined approach of pharmacophore-based virtual screening and functional readouts reveals that side chain modifications of the bridged six-membered ring structure of myrtenol are crucial for its modulatory potential at GABAA receptors.
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Affiliation(s)
- Sinem Milanos
- Institute for Clinical Neurobiology , Julius-Maximilians-Universität Würzburg , Versbacherstr. 5 , D-97078 Würzburg , Germany
- Department of Chemistry and Pharmacy, Food Chemistry, Emil-Fischer-Center , Friedrich-Alexander-Universität Erlangen-Nürnberg , D-90154 Erlangen , Germany
| | - Katharina Kuenzel
- Institute of Medical Biotechnology , Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91052 Erlangen , Germany
| | - Daniel F. Gilbert
- Institute of Medical Biotechnology , Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91052 Erlangen , Germany
| | - Dieter Janzen
- Institute for Clinical Neurobiology , Julius-Maximilians-Universität Würzburg , Versbacherstr. 5 , D-97078 Würzburg , Germany
| | - Manju Sasi
- Institute for Clinical Neurobiology , Julius-Maximilians-Universität Würzburg , Versbacherstr. 5 , D-97078 Würzburg , Germany
| | - Andrea Buettner
- Department of Chemistry and Pharmacy, Food Chemistry, Emil-Fischer-Center , Friedrich-Alexander-Universität Erlangen-Nürnberg , D-90154 Erlangen , Germany
- Department of Sensory Analytics , Fraunhofer-Institute for Process Engineering and Packaging , D-85354 Freising , Germany
| | - Thomas M. Frimurer
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research , University of Copenhagen , Copenhagen , Denmark
| | - Carmen Villmann
- Institute for Clinical Neurobiology , Julius-Maximilians-Universität Würzburg , Versbacherstr. 5 , D-97078 Würzburg , Germany
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Egbewande FA, Nilsson N, White JM, Coster MJ, Davis RA. The design, synthesis, and anti-inflammatory evaluation of a drug-like library based on the natural product valerenic acid. Bioorg Med Chem Lett 2017; 27:3185-3189. [DOI: 10.1016/j.bmcl.2017.05.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/04/2017] [Accepted: 05/06/2017] [Indexed: 11/26/2022]
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Moradi-Afrapoli F, Ebrahimi SN, Smiesko M, Hamburger M. HPLC-Based Activity Profiling for GABA A Receptor Modulators in Extracts: Validation of an Approach Utilizing a Larval Zebrafish Locomotor Assay. JOURNAL OF NATURAL PRODUCTS 2017; 80:1548-1557. [PMID: 28485933 DOI: 10.1021/acs.jnatprod.7b00081] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gamma-aminobutyric acid type A (GABAA) receptors are major inhibitory neurotransmitter receptors in the central nervous system and a target for numerous clinically important drugs used to treat anxiety, insomnia, and epilepsy. A series of allosteric GABAA receptor agonists was identified previously with the aid of HPLC-based activity profiling, whereby activity was tracked with an electrophysiological assay in Xenopus laevis oocytes. To accelerate the discovery process, an approach has been established for HPLC-based profiling using a larval zebrafish (Danio rerio) seizure model induced by pentylenetetrazol (PTZ), a pro-convulsant GABAA receptor antagonist. The assay was validated with the aid of representative GABAergic plant compounds and extracts. Various parameters that are relevant for the quality of results obtained, including PTZ concentration, the number of larvae, the incubation time, and the data analysis protocol, were optimized. The assay was then translated into an HPLC profiling protocol, and active compounds were tracked in extracts of Valeriana officinalis and Magnolia officinalis. For selected compounds the effects in the zebrafish larvae model were compared with data from in silico blood-brain barrier (BBB) permeability predictions, to validate the use for discovery of BBB-permeable natural products.
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Affiliation(s)
| | - Samad Nejad Ebrahimi
- Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University , G. C., Evin, Tehran, Iran
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Khom S, Hintersteiner J, Luger D, Haider M, Pototschnig G, Mihovilovic MD, Schwarzer C, Hering S. Analysis of β-Subunit-dependent GABAA Receptor Modulation and Behavioral Effects of Valerenic Acid Derivatives. J Pharmacol Exp Ther 2016; 357:580-90. [PMID: 27190170 PMCID: PMC4885513 DOI: 10.1124/jpet.116.232983] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 04/06/2016] [Indexed: 12/30/2022] Open
Abstract
Valerenic acid (VA)-a β2/3-selective GABA type A (GABAA) receptor modulator-displays anxiolytic and anticonvulsive effects in mice devoid of sedation, making VA an interesting drug candidate. Here we analyzed β-subunit-dependent enhancement of GABA-induced chloride currents (IGABA) by a library of VA derivatives and studied their effects on pentylenetetrazole (PTZ)-induced seizure threshold and locomotion. Compound-induced IGABA enhancement was determined in oocytes expressing α1β1γ2S, α1β2γ2S, or α1β3γ2S receptors. Effects on seizure threshold and locomotion were studied using C57BL/6N mice and compared with saline-treated controls. β2/3-selective VA derivatives such as VA-amide (VA-A) modulating α1β3γ2S (VA-A: Emax = 972 ± 69%, n = 6, P < 0.05) and α1β2γ2S receptors (Emax = 1119 ± 72%, n = 6, P < 0.05) more efficaciously than VA (α1β3γ2S: VA: Emax = 632 ± 88%, n = 9 versus α1β2γ2S: VA: Emax = 721 ± 68%, n = 6) displayed significantly more pronounced seizure threshold elevation than VA (saline control: 40.4 ± 1.4 mg/kg PTZ versus VA 10 mg/kg: 49.0 ± 1.8 mg/kg PTZ versus VA-A 3 mg/kg: 57.9 ± 1.9 mg/kg PTZ, P < 0.05). Similarly, VA's methylamide (VA-MA) enhancing IGABA through β3-containing receptors more efficaciously than VA (Emax = 1043 ± 57%, P < 0.01, n = 6) displayed stronger anticonvulsive effects. Increased potency of IGABA enhancement and anticonvulsive effects at lower doses compared with VA were observed for VA-tetrazole (α1β3γ2S: VA-TET: EC50 = 6.0 ± 1.0 μM, P < 0.05; VA-TET: 0.3 mg/kg: 47.3 ± 0.5 mg/kg PTZ versus VA: 10 mg/kg: 49.0 ± 1.8 mg/kg PTZ, P < 0.05). At higher doses (≥10 mg/kg), VA-A, VA-MA, and VA-TET reduced locomotion. In contrast, unselective VA derivatives induced anticonvulsive effects only at high doses (30 mg/kg) or did not display any behavioral effects. Our data indicate that the β2/3-selective compounds VA-A, VA-MA, and VA-TET induce anticonvulsive effects at low doses (≤10 mg/kg), whereas impairment of locomotion was observed at doses ≥10 mg/kg.
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Affiliation(s)
- S Khom
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - J Hintersteiner
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - D Luger
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - M Haider
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - G Pototschnig
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - M D Mihovilovic
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - C Schwarzer
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
| | - S Hering
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria (S.K., J.H., D.L., S.H.); Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria (M.H., G.P., M.D.M.); and Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria (C.S.)
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Hintersteiner J, Haider M, Luger D, Schwarzer C, Reznicek G, Jäger W, Khom S, Mihovilovic MD, Hering S. Esters of valerenic acid as potential prodrugs. Eur J Pharmacol 2014; 735:123-31. [PMID: 24680924 PMCID: PMC4062961 DOI: 10.1016/j.ejphar.2014.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/07/2014] [Accepted: 03/19/2014] [Indexed: 11/15/2022]
Abstract
Valerenic acid (VA) is a β2/3 subunit-specific modulator of γ-aminobutyric acid (GABA) type A (GABAA) receptors inducing anxiolysis. Here we analyze if VA-esters can serve as prodrugs and if different ester structures have different in vitro/in vivo effects. Modulation of GABAA receptors expressed in Xenopus oocytes was studied with 2-microelectrode-voltage-clamp. Anxiolytic effects of the VA-esters were studied on male C57BL/6N mice by means of the elevated plus maze-test; anticonvulsant properties were deduced from changes in seizure threshold upon pentylenetetrazole infusion. VA was detected in plasma confirming hydrolysis of the esters and release of VA in vivo. Esterification significantly reduced the positive allosteric modulation of GABAA (α1β3γ2S) receptors in vitro. in vivo, the studied VA-ester derivatives induced similar or even stronger anxiolytic and anticonvulsant action than VA. While methylation and propylation of VA resulted in faster onset of anxiolysis, the action of VA-ethylester was longer lasting, but occurred with a significant delay. The later finding is in line with the longer lasting anticonvulsant effects of this compound. The estimated VA plasma concentrations provided first insight into the release kinetics from different VA-esters. This might be an important step for its future clinical application as a potential non-sedative anxiolytic and anticonvulsant.
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Affiliation(s)
- Juliane Hintersteiner
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Maximilian Haider
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria.
| | - Denise Luger
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Christoph Schwarzer
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr-Straße 1, 1a A-6020 Innsbruck, Austria.
| | - Gottfried Reznicek
- Department of Pharmacognosy, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Walter Jäger
- Department of Clinical Pharmacy and Diagnostics, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Sophia Khom
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Marko D Mihovilovic
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria.
| | - Steffen Hering
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
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Sieghart W, Ramerstorfer J, Sarto-Jackson I, Varagic Z, Ernst M. A novel GABA(A) receptor pharmacology: drugs interacting with the α(+) β(-) interface. Br J Pharmacol 2012; 166:476-85. [PMID: 22074382 DOI: 10.1111/j.1476-5381.2011.01779.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
GABA(A) receptors are ligand-gated chloride channels composed of five subunits that can belong to different subunit classes. The existence of 19 different subunits gives rise to a multiplicity of GABA(A) receptor subtypes with distinct subunit composition; regional, cellular and subcellular distribution; and pharmacology. Most of these receptors are composed of two α, two β and one γ2 subunits. GABA(A) receptors are the site of action of a variety of pharmacologically and clinically important drugs, such as benzodiazepines, barbiturates, neuroactive steroids, anaesthetics and convulsants. Whereas GABA acts at the two extracellular β(+) α(-) interfaces of GABA(A) receptors, the allosteric modulatory benzodiazepines interact with the extracellular α(+) γ2(-) interface. In contrast, barbiturates, neuroactive steroids and anaesthetics seem to interact with solvent accessible pockets in the transmembrane domain. Several benzodiazepine site ligands have been identified that selectively interact with GABA(A) receptor subtypes containing α2βγ2, α3βγ2 or α5βγ2 subunits. This indicates that the different α subunit types present in these receptors convey sufficient structural differences to the benzodiazepine binding site to allow specific interaction with certain benzodiazepine site ligands. Recently, a novel drug binding site was identified at the α(+) β(-) interface. This binding site is homologous to the benzodiazepine binding site at the α(+) γ2(-) interface and is thus also strongly influenced by the type of α subunit present in the receptor. Drugs interacting with this binding site cannot directly activate but only allosterically modulate GABA(A) receptors. The possible importance of such drugs addressing a spectrum of receptor subtypes completely different from that of benzodiazepines is discussed.
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Affiliation(s)
- Werner Sieghart
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Vienna, Austria
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Ramharter J, Mulzer J. From Planning to Optimization: Total Synthesis of Valerenic Acid and Some Bioactive Derivatives. European J Org Chem 2012. [DOI: 10.1002/ejoc.201101834] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Zaugg J, Eickmeier E, Ebrahimi SN, Baburin I, Hering S, Hamburger M. Positive GABA(A) receptor modulators from Acorus calamus and structural analysis of (+)-dioxosarcoguaiacol by 1D and 2D NMR and molecular modeling. JOURNAL OF NATURAL PRODUCTS 2011; 74:1437-43. [PMID: 21563811 PMCID: PMC3199944 DOI: 10.1021/np200181d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In a two-microelectrode voltage clamp with Xenopus laevis oocytes, a petroleum ether extract of Acorus calamus rhizomes enhanced the GABA-induced chloride current through GABA(A) receptors of the α₁β₂γ(2S) subtype by 277% ± 9.7% (100 μg/mL). β-Asarone (1), (+)-dioxosarcoguaiacol (2), (+)-shyobunone (3), and (+)-preisocalamenediol (4) were subsequently identified as main active principles through HPLC-based activity profiling and targeted isolation. The compounds induced maximum potentiation of the chloride current ranging from 588% ± 126% (EC₅₀: 65.3 ± 21.6 μM) (2) to 1200% ± 163% (EC(50): 171.5 ± 34.6 μM) (1), whereas (-)-isoshyobunone (5) and (-)-acorenone (6) exhibited weak GABA(A) modulating properties (5: 164% ± 42.9%; EC₅₀: 109.4 ± 46.6 μM and 6: 241% ± 23.1%; EC₅₀: 34.0 ± 6.7 μM). The relative configuration of 2 was established as 4R*8S*10R* by NOESY experiments and conformational analysis.
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Affiliation(s)
- Janine Zaugg
- Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Eva Eickmeier
- Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Samad Nejad Ebrahimi
- Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
- Departement of Phytochemistry, Medicinal Plant and Drugs Research Institute, Shahid Beheshti University, G. C., Tehran, Iran
| | - Igor Baburin
- Departement of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Steffen Hering
- Departement of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Matthias Hamburger
- Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
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