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Lee MT, Mouri A, Kubota H, Lee HJ, Chang MH, Wu CY, Knutson DE, Mihovilovic M, Cook J, Sieghart W, Nabeshima T, Chiou LC. Targeting α6GABA A receptors as a novel therapy for schizophrenia: A proof-of-concept preclinical study using various animal models. Biomed Pharmacother 2022; 150:113022. [PMID: 35483195 DOI: 10.1016/j.biopha.2022.113022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/17/2022] [Accepted: 04/20/2022] [Indexed: 11/29/2022] Open
Abstract
GABAA receptors containing α6 subunits (α6GABAARs) in the cerebellum have -been implicated in schizophrenia. It was reported that the GABA synthesizing enzymes were downregulated whereas α6GABAARs were upregulated in postmortem cerebellar tissues of patients with schizophrenia and in a rat model induced by chronic phencyclidine (PCP). We have previously demonstrated that pyrazoloquinolinone Compound 6, an α6GABAAR-highly selective positive allosteric modulator (PAM), can rescue the disrupted prepulse inhibition (PPI) induced by methamphetamine (METH), an animal model mimicking the sensorimotor gating deficit based on the hyper-dopaminergic hypothesis of schizophrenia. Here, we demonstrate that not only Compound 6, but also its structural analogues, LAU463 and LAU159, with similarly high α6GABAAR selectivity and their respective deuterated derivatives (DK-I-56-1, DK-I-58-1 and DK-I-59-1) can rescue METH-induced PPI disruption. Besides, Compound 6 and DK-I-56-I can also rescue the PPI disruption induced by acute administration of PCP, an animal model based on the hypo-glutamatergic hypothesis of schizophrenia. Importantly, Compound 6 and DK-I-56-I, at doses not affecting spontaneous locomotor activity, can also rescue impairments of social interaction and novel object recognition in mice induced by chronic PCP treatments. At similar doses, Compound 6 did not induce sedation but significantly suppressed METH-induced hyperlocomotion. Thus, α6GABAAR-selective PAMs can rescue not only disrupted PPI but also hyperlocomotion, social withdrawal, and cognitive impairment, in both METH- and PCP-induced animal models mimicking schizophrenia, suggesting that they are a potential novel therapy for the three core symptoms, i.e. positive symptoms, negative symptoms, and cognitive impairment, of schizophrenia.
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Affiliation(s)
- Ming Tatt Lee
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur 56000, Malaysia
| | - Akihiro Mouri
- Department of Regulatory Science, Fujita Health University Graduate School of Health Sciences, Aichi 470-1192, Japan; Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Aichi 470-1192, Japan; Japanese Drug Organization of Appropriate Use and Research, Aichi 468-0069, Japan
| | - Hisayoshi Kubota
- Department of Regulatory Science, Fujita Health University Graduate School of Health Sciences, Aichi 470-1192, Japan
| | - Hsin-Jung Lee
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Man-Hsin Chang
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Chen-Yi Wu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Daniel E Knutson
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Marko Mihovilovic
- Institute of Applied Synthetic Chemistry, TU Wien, 1060 Vienna, Austria
| | - James Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences, Medical University Vienna, 1090 Wien, Austria
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Aichi 470-1192, Japan; Japanese Drug Organization of Appropriate Use and Research, Aichi 468-0069, Japan
| | - Lih-Chu Chiou
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; Graduate Institute of Acupuncture Science, China Medical University, Taichung 40402, Taiwan.
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Fabjan J, Koniuszewski F, Schaar B, Ernst M. Structure-Guided Computational Methods Predict Multiple Distinct Binding Modes for Pyrazoloquinolinones in GABA A Receptors. Front Neurosci 2021; 14:611953. [PMID: 33519364 PMCID: PMC7844064 DOI: 10.3389/fnins.2020.611953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/23/2020] [Indexed: 12/16/2022] Open
Abstract
Pyrazoloquinolinones (PQs) are a versatile class of GABAA receptor ligands. It has been demonstrated that high functional selectivity for certain receptor subtypes can be obtained by specific substitution patterns, but so far, no clear SAR rules emerge from the studies. As is the case for many GABAA receptor targeting chemotypes, PQs can interact with distinct binding sites on a given receptor pentamer. In pentamers of αβγ composition, such as the most abundant α1β2γ2 subtype, many PQs are high affinity binders of the benzodiazepine binding site at the extracellular α+/γ2- interfaces. There they display a functionally near silent, flumazenil-like allosteric activity. More recently, interactions with extracellular α+/β- interfaces have been investigated, where strong positive modulation can be steered toward interesting subtype preferences. The most prominent examples are functionally α6-selective PQs. Similar to benzodiazepines, PQs also seem to interact with sites in the transmembrane domain, mainly the sites used by etomidate and barbiturates. This promiscuity leads to potential contributions from multiple sites to net modulation. Developing ligands that interact exclusively with the extracellular α+/β- interfaces would be desired. Correlating functional profiles with binding sites usage is hampered by scarce and heterogeneous experimental data, as shown in our meta-analysis of aggregated published data. In the absence of experimental structures, bound states can be predicted with pharmacophore matching methods and with computational docking. We thus performed pharmacophore matching studies for the unwanted sites, and computational docking for the extracellular α1,6+/β3- interfaces. The results suggest that PQs interact with their binding sites with diverse binding modes. As such, rational design of improved ligands needs to take a complex structure-activity landscape with branches between sub-series of derivatives into account. We present a workflow, which is suitable to identify and explore potential branching points on the structure-activity landscape of any small molecule chemotype.
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Affiliation(s)
| | | | | | - Margot Ernst
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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3
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Tzeng HR, Lee MT, Fan PC, Knutson DE, Lai TH, Sieghart W, Cook J, Chiou LC. α6GABA A Receptor Positive Modulators Alleviate Migraine-like Grimaces in Mice via Compensating GABAergic Deficits in Trigeminal Ganglia. Neurotherapeutics 2021; 18:569-585. [PMID: 33111258 PMCID: PMC8116449 DOI: 10.1007/s13311-020-00951-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2020] [Indexed: 11/29/2022] Open
Abstract
Migraine is caused by hyperactivity of the trigeminovascular system, where trigeminal ganglia (TG) play an important role. This hyperactivity might originate from an underfunctional GABAergic system in TG. To investigate this possibility, we adapted a mouse model of migraine by inducing migraine-like grimaces in male mice via repeated injections of nitroglycerin (NTG, 10 mg/kg, i.p.), once every 2 days, for up to 5 sessions. Migraine-like facial pain scores were measured using the mouse grimace scale. Repeated NTG treatments in mice caused significant increases in migraine-like grimaces that were aborted and prevented by two anti-migraine agents sumatriptan and topiramate, respectively. After 5 sessions of NTG injections, the GABA-synthesizing enzyme, 65-kDa glutamate decarboxylase (GAD65), but not the GABA transporter 1 (GAT1) or the α6 subunit-containing GABAA receptors (α6GABAARs), was downregulated in mouse TG tissues. Taking advantage of the unaffected TG α6GABAAR expression in NTG-treated mice, we demonstrated that an α6GABAAR-selective positive allosteric modulator (PAM), DK-I-56-1, exhibited both abortive and prophylactic effects, comparable to those of sumatriptan and topiramate, respectively, in this migraine-mimicking mouse model. The brain-impermeable furosemide significantly prevented the effects of DK-I-56-1, suggesting its peripheral site of action, likely via preventing α6GABAAR modulation in TG. Results suggest that a decreased GABA synthesis caused by the reduced GAD65 expression in TG contributes to the trigeminovascular activation in this repeated NTG-induced migraine-mimicking model and that the unaltered α6GABAARs in TG are potential targets for migraine treatment. Thus, α6GABAAR-selective PAMs are potential anti-migraine agents for both abortive and preventive therapies.
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Affiliation(s)
- Hung-Ruei Tzeng
- Department of Pharmacology, Graduate Institute of Pharmacology College of Medicine, National Taiwan University, No. 1, Jen-Ai Rd., Section 1, Taipei, 10051, Taiwan
| | - Ming Tatt Lee
- Graduate Institute of Brain and Mind Sciences College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
- Faculty of Pharmaceutical Sciences, UCSI University, 56000, Kuala Lumpur, Malaysia
| | - Pi-Chuan Fan
- Department of Pediatrics, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
- Department of Pediatrics, National Taiwan University Hospital, Taipei, 10002, Taiwan
| | - Daniel E Knutson
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA
| | - Tzu-Hsuan Lai
- Department of Pediatrics, National Taiwan University Hospital, Taipei, 10002, Taiwan
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences, Medical University Vienna, 1090, Vienna, Austria
| | - James Cook
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA
| | - Lih-Chu Chiou
- Department of Pharmacology, Graduate Institute of Pharmacology College of Medicine, National Taiwan University, No. 1, Jen-Ai Rd., Section 1, Taipei, 10051, Taiwan.
- Graduate Institute of Brain and Mind Sciences College of Medicine, National Taiwan University, Taipei, 10051, Taiwan.
- Graduate Institute of Acupuncture Science, China Medical University, Taichung, 40402, Taiwan.
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5-[Aryloxypyridyl (or nitrophenyl)]-4H-1,2,4-triazoles as novel flexible benzodiazepine analogues: Synthesis, receptor binding affinity and lipophilicity-dependent anti-seizure onset of action. Bioorg Chem 2020; 106:104504. [PMID: 33279247 DOI: 10.1016/j.bioorg.2020.104504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 02/06/2023]
Abstract
A new series of 5-(2-aryloxy-4-nitrophenyl)-4H-1,2,4-triazoles and 5-(2-aryloxy-3-pyridyl)-4H-1,2,4-triazoles, possessing C-3 thio or alkylthio substituents, was synthesized and evaluated for their benzodiazepine receptor affinity and anti-seizure activity. These analogues revealed similar to significantly superior affinity to GABAA/benzodiazepine receptor complex (IC50 values of 0.04-4.1 nM), relative to diazepam as the reference drug (IC50 value of 2.4 nM). To determine the onset of anti-seizure activity, the time-dependent effectiveness of i.p. administration of compounds on pentylenetetrazole induced seizure threshold was studied and a very good relationship was observed between the lipophilicity (cLogP) and onset of action of studied analogues (r2 = 0.964). The minimum effective dose of the compounds, determined at the time the analogues showed their highest activity, was demonstrated to be 0.025-0.1 mg/kg, relative to diazepam (0.025 mg/kg).
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Simeone X, Iorio M, Siebert D, Rehman S, Schnürch M, Mihovilovic M, Ernst M. Defined concatenated α6α1β3γ2 GABAA receptor constructs reveal dual action of pyrazoloquinolinone allosteric modulators. Bioorg Med Chem 2019; 27:3167-3178. [DOI: 10.1016/j.bmc.2019.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 05/08/2019] [Accepted: 06/03/2019] [Indexed: 12/20/2022]
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Taghizadeh MJ, malakpouri GR, Javidan A. Improved and scalable methods for the synthesis of midazolam drug and its analogues using isocyanide reagents. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2019. [DOI: 10.1007/s13738-018-1555-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Kaur N. Synthesis of six- and seven-membered and larger heterocylces using Au and Ag catalysts. INORG NANO-MET CHEM 2019. [DOI: 10.1080/24701556.2019.1567544] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Navjeet Kaur
- Department of Chemistry, Banasthali Vidyapith, Banasthali, Rajasthan, India
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Siebert DCB, Bampali K, Puthenkalam R, Varagic Z, Sarto-Jackson I, Scholze P, Sieghart W, Mihovilovic MD, Schnürch M, Ernst M. Engineered Flumazenil Recognition Site Provides Mechanistic Insight Governing Benzodiazepine Modulation in GABA A Receptors. ACS Chem Biol 2018; 13:2040-2047. [PMID: 29989390 DOI: 10.1021/acschembio.8b00145] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The anxiolytic, anticonvulsant, muscle-relaxant, and sedative-hypnotic effects of benzodiazepine site ligands are mainly elicited by allosteric modulation of GABAA receptors via their extracellular αx+/γ2- ( x = 1, 2, 3, 5) interfaces. In addition, a low affinity binding site at the homologous α+/β- interfaces was reported for some benzodiazepine site ligands. Classical benzodiazepines and pyrazoloquinolinones have been used as molecular probes to develop structure-activity relationship models for benzodiazepine site activity. Considering all possible α+/β- and α+/γ- interfaces, such ligands potentially interact with as many as 36 interfaces, giving rise to undesired side effects. Understanding the binding modes at their binding sites will enable rational strategies to design ligands with desired selectivity profiles. Here, we compared benzodiazepine site ligand interactions in the high affinity α1+/γ2- site with the homologous α1+/β3- site using a successive mutational approach. We incorporated key amino acids known to contribute to high affinity benzodiazepine binding of the γ2- subunit into the β3- subunit, resulting in a quadruple mutant β3(4mut) with high affinity flumazenil (Ro 15-1788) binding properties. Intriguingly, some benzodiazepine site ligands displayed positive allosteric modulation in the tested recombinant α1β3(4mut) constructs while diazepam remained inactive. Consequently, we performed in silico molecular docking in the wildtype receptor and the quadruple mutant. The results led to the conclusion that different benzodiazepine site ligands seem to use distinct binding modes, rather than a common binding mode. These findings provide structural hypotheses for the future optimization of both benzodiazepine site ligands, and ligands that interact with the homologous α+/β- sites.
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Affiliation(s)
- David C. B. Siebert
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Vienna, Austria
| | - Konstantina Bampali
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Roshan Puthenkalam
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Zdravko Varagic
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | | | - Petra Scholze
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Werner Sieghart
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Marko D. Mihovilovic
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Vienna, Austria
| | - Michael Schnürch
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Vienna, Austria
| | - Margot Ernst
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
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The α6 subunit-containing GABA A receptor: A novel drug target for inhibition of trigeminal activation. Neuropharmacology 2018; 140:1-13. [PMID: 30016665 DOI: 10.1016/j.neuropharm.2018.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/29/2018] [Accepted: 07/12/2018] [Indexed: 01/21/2023]
Abstract
Novel treatments against migraine are an urgent medical requirement. The α6 subunit-containing GABAA receptors (α6GABAARs) are expressed in trigeminal ganglia (TG), the hub of the trigeminal vascular system (TGVS) that is involved in the pathogenesis of migraine. Here we reveal an unprecedented role of α6GABAARs in ameliorating TGVS activation using several pharmacological approaches in an animal model mimicking pathological changes in migraine. TGVS activation was induced by intra-cisternal (i.c.) instillation of capsaicin in Wistar rats. Centrally, i.c. capsaicin activated the trigeminal cervical complex (TCC) measured by the increased number of c-Fos-immunoreactive (c-Fos-ir) TCC neurons. Peripherally, it elevated calcitonin gene-related peptide immunoreactivity (CGRP-ir) in TG and depleted CGRP-ir in the dura mater. Pharmacological approaches included a recently identified α6GABAAR-selective positive allosteric modulator (PAM), the pyrazoloquinolinone Compound 6, two α6GABAAR-active PAMs (Ro15-4513 and loreclezole), an α6GABAAR-inactive benzodiazepine (diazepam), an α6GABAAR-selective antagonist (furosemide), and a clinically effective antimigraine agent (topiramate). We examined effects of these compounds on both central and peripheral TGVS responses induced by i.c. capsaicin. Compound 6 (3-10 mg/kg, i.p.) significantly attenuated the TCC neuronal activation and TG CGRP-ir elevation, and dural CGRP depletion induced by capsaicin. All these effects of Compound 6 were mimicked by topiramate, Ro15-4513 and loreclezole, but not by diazepam. The brain-impermeable furosemide antagonized the peripheral, but not central, effects of Compound 6. These results suggest that the α6GABAAR in TG is a novel drug target for TGVS activation and that α6GABAAR-selective PAMs have the potential to be developed as a novel pharmacotherapy for migraine.
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Chiou LC, Lee HJ, Ernst M, Huang WJ, Chou JF, Chen HL, Mouri A, Chen LC, Treven M, Mamiya T, Fan PC, Knutson DE, Witzigmann C, Cook J, Sieghart W, Nabeshima T. Cerebellar α 6 -subunit-containing GABA A receptors: a novel therapeutic target for disrupted prepulse inhibition in neuropsychiatric disorders. Br J Pharmacol 2018. [PMID: 29518821 DOI: 10.1111/bph.14198] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The pathophysiological role of α6 -subunit-containing GABAA receptors, which are mainly expressed in cerebellar granule cells, remains unclear. Recently, we demonstrated that hispidulin, a flavonoid isolated from a local herb that remitted a patient's intractable motor tics, attenuated methamphetamine-induced hyperlocomotion in mice as a positive allosteric modulator (PAM) of cerebellar α6 GABAA receptors. Here, using hispidulin and a selective α6 GABAA receptor PAM, the pyrazoloquinolinone Compound 6, we revealed an unprecedented role of cerebellar α6 GABAA receptors in disrupted prepulse inhibition of the startle response (PPI), which reflects sensorimotor gating deficits manifested in several neuropsychiatric disorders. EXPERIMENTAL APPROACH PPI disruptions were induced by methamphetamine and NMDA receptor antagonists in mice. Effects of the tested compounds were measured in Xenopus oocytes expressing recombinant α6 β3 γ2S GABAA receptors. KEY RESULTS Hispidulin given i.p. or by bilateral intracerebellar (i.cb.) injection rescued PPI disruptions induced by methamphetamine, ketamine, MK-801 and phencyclidine. Intracerebellar effects of hispidulin were mimicked by Ro15-4513 and loreclezole (two α6 GABAA receptor PAMs), but not by diazepam (an α6 GABAA receptor-inactive benzodiazepine) and were antagonized by furosemide (i.cb.), an α6 GABAA receptor antagonist. Importantly, Compound 6 (i.p.) also rescued methamphetamine-induced PPI disruption, an effect prevented by furosemide (i.cb.). Both hispidulin and Compound 6 potentiated α6 β3 γ2S GABAA receptor-mediated GABA currents. CONCLUSIONS AND IMPLICATIONS Positive allosteric modulation of cerebellar α6 GABAA receptors rescued disrupted PPI by attenuating granule cell activity. α6 GABAA receptor-selective PAMs are potential medicines for treating sensorimotor gating deficits in neuropsychiatric disorders. A mechanistic hypothesis is based on evidence for cerebellar contributions to cognitive functioning including sensorimotor gating.
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Affiliation(s)
- Lih-Chu Chiou
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan,Graduate Institute of Brain and Mind Sciences, National TaiwanUniversity, Taipei, Taiwan,Graduate Institute of Acupuncture Science, Taichung, Taiwan
| | - Hsin-Jung Lee
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Margot Ernst
- Center for Brain Research, Department of Molecular Neurosciences, Medical University Vienna, Vienna, Austria
| | - Wei-Jan Huang
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan
| | - Jui-Feng Chou
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Hon-Lie Chen
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Akihiro Mouri
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan,Advanced Diagnostic System Research Laboratory, Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Liang-Chieh Chen
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan
| | - Marco Treven
- Center for Brain Research, Department of Molecular Neurosciences, Medical University Vienna, Vienna, Austria
| | - Takayoshi Mamiya
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Pi-Chuan Fan
- Department of Pediatrics, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Daniel E Knutson
- Department of Chemistry and Biochemistry, University of Wisconsin – Milwaukee, Milwaukee, WI, USA
| | - Chris Witzigmann
- Department of Chemistry and Biochemistry, University of Wisconsin – Milwaukee, Milwaukee, WI, USA
| | - James Cook
- Department of Chemistry and Biochemistry, University of Wisconsin – Milwaukee, Milwaukee, WI, USA
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences, Medical University Vienna, Vienna, Austria
| | - Toshitaka Nabeshima
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan,Advanced Diagnostic System Research Laboratory, Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan,Aino University, Ibaraki, Japan
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11
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Knutson DE, Kodali R, Divović B, Treven M, Stephen MR, Zahn NM, Dobričić V, Huber AT, Meirelles MA, Verma RS, Wimmer L, Witzigmann C, Arnold LA, Chiou LC, Ernst M, Mihovilovic MD, Savić MM, Sieghart W, Cook JM. Design and Synthesis of Novel Deuterated Ligands Functionally Selective for the γ-Aminobutyric Acid Type A Receptor (GABA AR) α6 Subtype with Improved Metabolic Stability and Enhanced Bioavailability. J Med Chem 2018; 61:2422-2446. [PMID: 29481759 DOI: 10.1021/acs.jmedchem.7b01664] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent reports indicate that α6β2/3γ2 GABAAR selective ligands may be important for the treatment of trigeminal activation-related pain and neuropsychiatric disorders with sensori-motor gating deficits. Based on 3 functionally α6β2/3γ2 GABAAR selective pyrazoloquinolinones, 42 novel analogs were synthesized, and their in vitro metabolic stability and cytotoxicity as well as their in vivo pharmacokinetics, basic behavioral pharmacology, and effects on locomotion were investigated. Incorporation of deuterium into the methoxy substituents of the ligands increased their duration of action via improved metabolic stability and bioavailability, while their selectivity for the GABAAR α6 subtype was retained. 8b was identified as the lead compound with a substantially improved pharmacokinetic profile. The ligands allosterically modulated diazepam insensitive α6β2/3γ2 GABAARs and were functionally silent at diazepam sensitive α1β2/3γ2 GABAARs, thus no sedation was detected. In addition, these analogs were not cytotoxic, which render them interesting candidates for treatment of CNS disorders mediated by GABAAR α6β2/3γ2 subtypes.
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Affiliation(s)
- Daniel E Knutson
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Revathi Kodali
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Branka Divović
- Department of Pharmacology, Faculty of Pharmacy , University of Belgrade , Vojvode Stepe 450 , 11221 Belgrade , Serbia
| | - Marco Treven
- Department of Molecular Neurosciences, Center for Brain Research , Medical University of Vienna , Spitalgasse 4 , A-1090 Vienna , Austria
| | - Michael R Stephen
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Nicolas M Zahn
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Vladimir Dobričić
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy , University of Belgrade , Vojvode Stepe 450 , 11221 Belgrade , Serbia
| | - Alec T Huber
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Matheus A Meirelles
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Ranjit S Verma
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Laurin Wimmer
- TU Wien-Institute of Applied Synthetic Chemistry , Getreidemarkt 9/163 , A-1060 Vienna , Austria
| | - Christopher Witzigmann
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Leggy A Arnold
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
| | - Lih-Chu Chiou
- Graduate Institute of Acupuncture Science , China Medical University , Taichung 40402 , Taiwan
| | - Margot Ernst
- Department of Molecular Neurosciences, Center for Brain Research , Medical University of Vienna , Spitalgasse 4 , A-1090 Vienna , Austria
| | - Marko D Mihovilovic
- TU Wien-Institute of Applied Synthetic Chemistry , Getreidemarkt 9/163 , A-1060 Vienna , Austria
| | - Miroslav M Savić
- Department of Pharmacology, Faculty of Pharmacy , University of Belgrade , Vojvode Stepe 450 , 11221 Belgrade , Serbia
| | - Werner Sieghart
- Department of Molecular Neurosciences, Center for Brain Research , Medical University of Vienna , Spitalgasse 4 , A-1090 Vienna , Austria
| | - James M Cook
- Department of Chemistry and Biochemistry, Milwaukee Institute for Drug Discovery , University of Wisconsin-Milwaukee , 3210 N. Cramer St. , Milwaukee , Wisconsin 53211 , United States
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Malvacio I, Cuzzolin A, Sturlese M, Vera DMA, Moyano EL, Moro S. Synthesis and preliminary structure-activity relationship study of 2-aryl-2H-pyrazolo[4,3-c]quinolin-3-ones as potential checkpoint kinase 1 (Chk1) inhibitors. J Enzyme Inhib Med Chem 2017; 33:171-183. [PMID: 29210298 PMCID: PMC6010083 DOI: 10.1080/14756366.2017.1404592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The serine-threonine checkpoint kinase 1 (Chk1) plays a critical role in the cell cycle arrest in response to DNA damage. In the last decade, Chk1 inhibitors have emerged as a novel therapeutic strategy to potentiate the anti-tumour efficacy of cytotoxic chemotherapeutic agents. In the search for new Chk1 inhibitors, a congeneric series of 2-aryl-2 H-pyrazolo[4,3-c]quinolin-3-one (PQ) was evaluated by in-vitro and in-silico approaches for the first time. A total of 30 PQ structures were synthesised in good to excellent yields using conventional or microwave heating, highlighting that 14 of them are new chemical entities. Noteworthy, in this preliminary study two compounds 4e2 and 4h2 have shown a modest but significant reduction in the basal activity of the Chk1 kinase. Starting from these preliminary results, we have designed the second generation of analogous in this class and further studies are in progress in our laboratories.
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Affiliation(s)
- Ivana Malvacio
- a Department of Organic Chemistry, INFIQC, School of Chemical Sciences , National University of Cordoba , Cordoba , Argentina.,b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
| | - Alberto Cuzzolin
- b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
| | - Mattia Sturlese
- b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
| | - D Mariano A Vera
- c Department of Chemistry, QUIAMM-INBIOTEC, School of Exact and Natural Sciences , National University of Mar del Plata , Mar del Plata , Buenos Aires , Argentina
| | - E Laura Moyano
- a Department of Organic Chemistry, INFIQC, School of Chemical Sciences , National University of Cordoba , Cordoba , Argentina
| | - Stefano Moro
- b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
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A Review of the Updated Pharmacophore for the Alpha 5 GABA(A) Benzodiazepine Receptor Model. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2015; 2015:430248. [PMID: 26682068 PMCID: PMC4657098 DOI: 10.1155/2015/430248] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 06/16/2015] [Accepted: 07/02/2015] [Indexed: 12/22/2022]
Abstract
An updated model of the GABA(A) benzodiazepine receptor pharmacophore of the α5-BzR/GABA(A) subtype has been constructed prompted by the synthesis of subtype selective ligands in light of the recent developments in both ligand synthesis, behavioral studies, and molecular modeling studies of the binding site itself. A number of BzR/GABA(A) α5 subtype selective compounds were synthesized, notably α5-subtype selective inverse agonist PWZ-029 (1) which is active in enhancing cognition in both rodents and primates. In addition, a chiral positive allosteric modulator (PAM), SH-053-2′F-R-CH3 (2), has been shown to reverse the deleterious effects in the MAM-model of schizophrenia as well as alleviate constriction in airway smooth muscle. Presented here is an updated model of the pharmacophore for α5β2γ2 Bz/GABA(A) receptors, including a rendering of PWZ-029 docked within the α5-binding pocket showing specific interactions of the molecule with the receptor. Differences in the included volume as compared to α1β2γ2, α2β2γ2, and α3β2γ2 will be illustrated for clarity. These new models enhance the ability to understand structural characteristics of ligands which act as agonists, antagonists, or inverse agonists at the Bz BS of GABA(A) receptors.
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Mashayekh S, Rahmanipour N, Mahmoodi B, Ahmadi F, Motaharian D, Shahhosseini S, Shafaroodi H, Banafshe HR, Shafiee A, Navidpour L. Synthesis, receptor affinity and effect on pentylenetetrazole-induced seizure threshold of novel benzodiazepine analogues: 3-Substituted 5-(2-phenoxybenzyl)-4H-1,2,4-triazoles and 2-amino-5-(phenoxybenzyl)-1,3,4-oxadiazoles. Bioorg Med Chem 2014; 22:1929-37. [DOI: 10.1016/j.bmc.2014.01.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 10/25/2022]
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Allosteric modulation of GABA(A) receptor subtypes:effects on visual recognition and visuospatial working memory in rhesus monkeys [corrected]. Neuropsychopharmacology 2013; 38:2315-25. [PMID: 23722241 PMCID: PMC3773684 DOI: 10.1038/npp.2013.137] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/21/2013] [Accepted: 05/21/2013] [Indexed: 11/08/2022]
Abstract
Non-selective positive allosteric modulators (PAMs) of GABAA receptors (GABAARs) are known to impair anterograde memory. The role of the various GABAAR subtypes in the memory-impairing effects of non-selective GABAAR PAMs has not been fully elucidated. The current study assessed, in rhesus monkeys, effects of modulation of α1, α2/3, and α5GABAARs on visual recognition and spatial working memory using delayed matching-to-sample (DMTS) and self-ordered spatial search (SOSS) procedures, respectively. The DMTS procedure (n=8) involved selecting a previously presented 'sample' image from a set of multiple images presented after a delay. The SOSS procedure (n=6) involved touching a number of boxes without repeats. The non-selective GABAAR PAM triazolam and the α1GABAA preferential PAMS zolpidem and zaleplon reduced accuracy in both procedures, whereas the α5GABAA preferential PAMs SH-053-2'F-R-CH3 and SH-053-2'F-S-CH3, and the α2/3GABAA preferential PAM TPA023B were without effects on accuracy or trial completion. The low-efficacy α5GABAAR negative allosteric modulator (NAM) PWZ-029 slightly increased only DMTS accuracy, whereas the high-efficacy α5GABAAR NAMs RY-23 and RY-24 did not affect accuracy under either procedure. Finally, the slopes of the accuracy dose-effect curves for triazolam, zolpidem, and zaleplon increased with box number in the SOSS procedure, but were equivalent across DMTS delays. The present results suggest that (1) α1GABAARs, compared with α2/3 and α5GABAARs, are primarily involved in the impairment, by non-selective GABAAR PAMs, of visual recognition and visuospatial working memory in nonhuman primates; and (2) relative cognitive impairment produced by positive modulation of GABAARs increases with number of locations to be remembered, but not with the delay for remembering.
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Kumar A, Li Z, Sharma SK, Parmar VS, Eycken EVVD. An Expedient Route to Imidazo[1,4]diazepin-7-ones via A Post-Ugi Gold-Catalyzed Heteroannulation. Org Lett 2013; 15:1874-7. [DOI: 10.1021/ol400526a] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Amit Kumar
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Zhenghua Li
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Sunil K. Sharma
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Virinder S. Parmar
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Erik V. Van der Eycken
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
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Synthesis, pharmacological studies and molecular modeling of some tetracyclic 1,3-diazepinium chlorides. Bioorg Med Chem 2009; 18:909-21. [PMID: 19962901 DOI: 10.1016/j.bmc.2009.11.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 11/12/2009] [Accepted: 11/14/2009] [Indexed: 11/22/2022]
Abstract
Seven new 1,3-diazepinium chlorides exhibiting some structural similarities to the 1,4-benzodiazepines were synthesized. In a Hippocratic screen using mice, three of these salts, 3-methoxy-6-oxo-7,13-dihydro-6H-benzofuro[2,3-e]pyrido[1,2-a][1,3]diazepin-12-ium chloride (8a), 3-methoxy-9-methyl-6-oxo-7,13-dihydro-6H-benzofuro[2,3-e]pyrido[1,2-a][1,3]diazepin-12-ium chloride (8c) and 3-methoxy-11-methyl-6-oxo-7,13-dihydro-6H-benzofuro[2,3-e]pyrido[1,2-a][1,3]diazepin-12-ium chloride (8e) were examined for their effect on the central nervous system, and their activities compared to that of diazepam. On their own, salts 8a, 8c and 8e solicited no sedative effects on the behaviour of the animals. However, they elicited significant effects in combination with diazepam on diazepam-induced activities such as decreased motor activity, ataxia and loss of righting reflex. Compounds 8a and 8c were fitted into the pharmacophore/receptor model developed by Cook et al. with interaction at the L(1), H(1) and A(2) sites indicating that they are potential inverse agonists of the Bz receptor. The compounds displayed some affinity for the alpha1 isoform of the GABA(A)/BzR (L(Di) interaction) but are non-selective for alpha5 (no L(2) interaction). Results of binding affinity studies showed that compound 8a is mildly selective for the alpha1 receptor although not very potent (K(i)=746.5nM). The significant potentiation of diazepam-induced ataxia and decreased motor activity by compounds 8a and 8c in the Hippocratic screen may be associated with alpha1 selectivity.
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Yang J, Teng Y, Ara S, Rallapalli S, Cook JM. An Improved Process for the Synthesis of 4H-Imidazo[1,5-a][1,4]benzodiazepines. SYNTHESIS-STUTTGART 2009; 2009:1036-1040. [PMID: 19936036 PMCID: PMC2779034 DOI: 10.1055/s-0028-1083358] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The construction of CNS active imidazo[1,5-a][1,4]benzodiazepines has been improved in a one-pot annulation process.
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Affiliation(s)
- Jie Yang
- Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, U.S.A Fax+14142295530;
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Hu L, Wu H, Lin W, Jiang J, Yu R. Quantitative Structure–Activity Relationship Studies for the Binding Affinities of Imidazobenzodiazepines for the α6 Benzodiazepine Receptor Isoform Utilizing Optimized Blockwise Variable Combination by Particle Swarm Optimization for Partial Least Squares Modeling. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/qsar.200530204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Akbarzadeh T, Tabatabai SA, Khoshnoud MJ, Shafaghi B, Shafiee A. Design and synthesis of 4H-3-(2-phenoxy)phenyl-1,2,4-triazole derivatives as benzodiazepine receptor agonists. Bioorg Med Chem 2003; 11:769-73. [PMID: 12538007 DOI: 10.1016/s0968-0896(02)00469-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A series of new 5-substituted analogues of 4H-3-(2-phenoxy)phenyl-1,2,4-triazole and its chlorinated derivatives was designed and prepared. Conformational analysis and superimposition of energy minima conformers of the compounds on estazolam, a known benzodiazepine receptor agonist, revealed that the main proposed benzodiazepine pharmacophores were well matched. Rotarod and pentylenetetrazole-induced lethal convulsion tests showed that the introduction of an amino group in position 5 of 1,2,4-triazole ring especially in chlorinated derivatives had the best effect which was comparable with diazepam.
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Affiliation(s)
- Tahmineh Akbarzadeh
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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22
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The isolation and use of a benzodiazepine iminochloride for the efficient construction of flumazenil. Tetrahedron Lett 2003. [DOI: 10.1016/s0040-4039(03)00078-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Harris DL, Loew G. Development and assessment of a 3D pharmacophore for ligand recognition of BDZR/GABAA receptors initiating the anxiolytic response. Bioorg Med Chem 2000; 8:2527-38. [PMID: 11092538 DOI: 10.1016/s0968-0896(00)00185-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Benzodiazepine receptor (BDZR) ligands are structurally diverse compounds that bind to specific binding sites on GABAA receptors and allosterically modulate the effect of GABA on chloride flux. The binding of BDZR ligands to this receptor system results in activity at multiple behavioral end points including anxiolytic, sedative, hyperphagic, anticonvulsant and hyperthermic effects. In the work presented here, 17 structurally diverse BDZR ligands of the receptors initiating the anxiolytic response have been studied using a systematic computational procedure developed in our laboratory. Using this procedure, a five component 3D recognition pharmacophore was obtained consisting of two proton acceptors, a hydrophobic group, an aromatic electron accepting ring and a ring containing polar moieties, all found in a common geometric arrangement in the 15 compounds with an effect at the anxiolytic end point and absent in two control compounds. The 3D pharmacophore developed was validated by searching 3D databases and finding known BDZR ligands active at the anxiolytic end point, including 1,4-BDZ derivatives, imidazo BDZ and beta-carboline ligands.
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Affiliation(s)
- D L Harris
- Molecular Research Institute, Mountain View, CA 94043, USA.
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June HL, Cason CR, Cheatham G, Lui R, Gan T, Cook JM. GABAA-benzodiazepine receptors in the striatum are involved in the sedation produced by a moderate, but not an intoxicating ethanol dose in outbred Wistar rats. Brain Res 1998; 794:103-18. [PMID: 9630547 DOI: 10.1016/s0006-8993(98)00222-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The role of the dorsal striatum in mediating the sedation produced by a moderate (0.75 g/kg) and an intoxicating (1.25 g/kg) EtOH dose was investigated in the open field by determining the capacity of direct intrastriatal injections of RY 008, a partial inverse agonist of the benzodiazepine (BDZ) receptor, to antagonize EtOH's effects. SR 95531, the competitive high-affinity GABAA antagonist was used as a reference compound. Intrastriatal RY 008 (50, 500 ng) and SR 95531 (50 ng) antagonized the sedation produced by the 0.75 g/kg EtOH dose. However, RY 008 did not alter the sedation produced by the 1.25 g/kg dose. RY 008 alone was without effect. RY 008 also failed to negatively modulate GABAergic function at alpha1beta2gamma2 or alpha6beta2gamma2 receptor subtypes expressed in Xenopus oocytes. Intrastriatal modulation of the moderate EtOH dose was site specific: no antagonism by RY 008 after intraaccumbens infusions was observed. The results suggest that central GABAA-BDZ receptors in the dorsal striatum play an important role in mediating the sedation produced by a moderate EtOH dose in the open field.
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Affiliation(s)
- H L June
- Department of Psychology, Purdue School of Science, Indiana University-Purdue University, Indianapolis, IN 46202, USA.
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June HL, Torres L, Cason CR, Hwang BH, Braun MR, Murphy JM. The novel benzodiazepine inverse agonist RO19-4603 antagonizes ethanol motivated behaviors: neuropharmacological studies. Brain Res 1998; 784:256-75. [PMID: 9518641 DOI: 10.1016/s0006-8993(97)01380-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The novel imidazothienodiazepine inverse agonist RO19-4603 has been reported to attenuate EtOH intake in home cage drinking tests for at least 24 h post-drug administration after systemic administration. In the present study, selectively bred alcohol-preferring (P) rats were trained under a concurrent (FR4-FR4) operant schedule to press one lever for EtOH (10% v/v) and another lever for saccharin (0.05% or 0.75% g/v), then dose-response and timecourse effects of RO19-4603 were evaluated. Systemic RO19-4603 injections (0.0045-0.3 mg/kg; i.p.) profoundly reduced EtOH responding by as much as 97% of vehicle control on day 1. No effects were seen on saccharin responding except with the highest dose level (0.3 mg/kg). In a second experiment, microinjections of RO19-4603 (2-100 ng) directly into the nucleus accumbens (NA) suppressed EtOH responding on day 1 by as much as 53% of control: Control injections dorsal to the NA or ventral tegmental area did not significantly alter EtOH or saccharin responding. On day 2, rats in both experiments received no RO19-4603 treatments; however, all 7 of the i.p. doses, and all 3 of the intra-NA infusions continued to significantly suppress EtOH responding by 43-85% of vehicle control levels. In addition, i.p. injections of RO19-4603 produced a dose-dependent decrease in the slope of the cumulative record for EtOH responding, while concomitantly producing a dose-dependent increase in the slope for saccharin responding. RO19-4603's actions appear to be mediated via recognition sites at GABAA-BDZ receptors which regulate EtOH reinforcement, and not via mechanisms regulating ingestive behaviors. Based on recent in situ hybridization studies in our laboratory, we hypothesize that occupation of alpha4 containing GABAA diazepam insensitive (DI) receptors in the NA, may mediate in part, the RO19-4603 suppression of EtOH responding in EtOH-seeking P rats.
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Affiliation(s)
- H L June
- Department of Psychology, Indiana University School of Medicine, Indiana University-Purdue University, Indianapolis, IN 46202, USA
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Krogsgaard-Larsen P, Fr∅lund B, Kristiansen U, Frydenvang K, Ebert B. GABAA and GABAB receptor agonists, partial agonists, antagonists and modulators: design and therapeutic prospects. Eur J Pharm Sci 1997. [DOI: 10.1016/s0928-0987(97)10009-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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XIIth international symposium on radiopharmaceutical chemistry: Abstracts and programme. J Labelled Comp Radiopharm 1997. [DOI: 10.1002/jlcr.2580400601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Varano F, Catarzi D, Colotta V, Cecchi L, Filacchioni G, Galli A, Costagli C. Structure-activity relationship studies of novel pyrazolo[1,5-c][1,3]benzoxazines: synthesis and benzodiazepine receptor affinity. Arch Pharm (Weinheim) 1996; 329:529-34. [PMID: 9038420 DOI: 10.1002/ardp.19963291204] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Some 2-arylpyrazolo[1,5-c][1,3]benzoxazin-5-ones 1 and 5- oxopyrazolo[1,5-c][1,3]benzoxazin-2-carboxylates 2 were prepared and biologically evaluated for their binding at benzodiazepine receptor (BZR) in rat cortical membranes. Structure-activity relationship studies suggest that, although proton donor d and proton acceptor a1 are both optional pharmacophoric descriptors, at least one of them must be present for good BZR affinity. When the proton donor d is not present, the heteroatom acceptor a1 is necessary either in the tricyclic core or in the appended substituent at the C-2 to obtain sub-micromolar BZR affinity.
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Affiliation(s)
- F Varano
- Dipartimento di Scienze Farmaceutiche, Università di Firenze, Italy
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Pringle AK, Gardner CR, Walker RJ. Biphasic actions of the benzodiazepine receptor inverse agonist RU34347 in the rat cerebellar slice. Brain Res 1996; 715:155-62. [PMID: 8739634 DOI: 10.1016/0006-8993(95)01571-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have characterised the biphasic response of the benzodiazepine receptor inverse agonist RU34347 in the rat cerebellar slice preparation using extracellular electrophysiological recordings from Purkinje cells. RU34347 (10 fM-10 nM) produced an increase in GABA(A)-mediated inhibition at between 10 fM and 10 nM, a response normally associated with benzodiazepine agonists. This response was biphasic, being dose dependent between 10 fM and the peak effect at 10 pM, and inversely related to concentration between 100 pM and 10 nM. Associated with this increase in inhibition was a decrease in firing rate, also showing a biphasic concentration-response relationship. The agonist-like response was composed of two elements, an initial increase occurring after 5 min followed by a slow decline over the next 20 min. This second, declining, phase was more evident at higher concentrations of RU34347. The peak effect seen at 10 pM was fully antagonised by 1 microM flumazenil, a benzodiazepine receptor antagonist. This concentration of flumazenil also antagonised the decrease in firing rate induced by 10 pM RU34347. The response to 10 nM RU34347 was further characterised since the largest second phase decline was demonstrated at this concentration. 10 nM flumazenil fully antagonised the second, declining, phase of the response, but not the magnitude of the initial increase. A partial antagonism of the peak effect was seen with 1 microM flumazenil, and a full antagonism at 10 microM flumazenil. This effect was similar to that observed with Ro15-4513 in a previous study. Therefore, we investigated the binding of RU34347 to diazepam-insensitive benzodiazepine receptors. [3H]Ro15-4513 was displaced by Ro15-4513, flumazenil and Ro19-4603, but not by RU34347. Therefore, although the electrophysiological data correlate well with that previously reported for Ro15-4513, RU34347 does not displace Ro15-4513 binding at the diazepam-insensitive benzodiazepine receptor. Therefore, either both ligands bind to complimentary sites on the same receptor complex, or both induce a similar physiological response through an action on different receptors.
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Affiliation(s)
- A K Pringle
- Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Southampton, UK
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31
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Gunnersen D, Kaufman CM, Skolnick P. Pharmacological properties of recombinant "diazepam-insensitive" GABAA receptors. Neuropharmacology 1996; 35:1307-14. [PMID: 9014146 DOI: 10.1016/s0028-3908(96)00054-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Both native and recombinant "diazepam-insensitive" GABAA receptors (DI) are characterized by the very low affinities of prototypic 1,4-benzodiazepines such as diazepam and the high affinity of an imidazobenzodiazepine, Ro 15-4513. The presence of either an alpha 4 or alpha 6 subunit imparts this unusual pharmacological profile to DI. Based on the affinities of these compounds at recombinant DI, the pharmacological properties of alpha 4- and alpha 6-bearing receptor isoforms appear to be very similar if not identical. Using a larger sample of structurally diverse compounds, we now demonstrate distinct but related ligand binding profiles of recombinant alpha 4 beta 2 gamma 2 and alpha 6 beta 2 gamma 2 DI. Comparison of 18 ligands drawn from three principal structural groups (beta-carbolines, imidazobenzodiazepines and pyrazoloquinolinones) revealed that the affinity of at least one representative from each group differed by > 5-fold between alpha 4- and alpha 6 beta 2 gamma 2 receptors. While the high correlation (r2 = 0.926; p < 0.001) obtained between the affinities of these ligands at alpha 4- and alpha 6-containing receptors underscores the similarity between these receptor isoforms, a significant deviation of the slope of this correlation (0.792; 95% C.I. 0.673-0.911) from unity is substantive evidence that these DI possess distinct pharmacological profiles. These findings indicate that it is feasible to develop selective ligands for these DI isoforms.
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Affiliation(s)
- D Gunnersen
- Laboratory of Neuroscience, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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