1
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Singh M, Malviya M, Yadav VB, Nikhil A, Gupta M. Synthesis of imidazole-fused nitrogen-bridgehead heterocycles catalysed by lipase and their antifungal and antimicrobial bioactivity. RSC Adv 2024; 14:5037-5044. [PMID: 38332786 PMCID: PMC10848895 DOI: 10.1039/d3ra07145f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/18/2024] [Indexed: 02/10/2024] Open
Abstract
An effective approach for selective C-N bond formation for synthesising imidazo[1,2-a] pyridine-based heterocycles using porcine pancreatic lipase (PPL) as a biocatalyst has been devised. Under moderate conditions, a series of imidazo[1,2-a]pyridine-based heterocycle derivatives were synthesised with remarkable selectivity in good-to-excellent yields (89-95%). Further, the antimicrobial and antifungal activities of derivatives 3ha, 3ka, 3fa, 3hc, and 3eb were observed, and they were found to be biologically active in antimicrobial susceptibility tests for Gram-positive bacteria (Enterococcus faecalis ATCC 29212 and Staphylococcus auris ATCC 25923), Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) and fungal strains (Candida albicans ATCC 90028 and Candida tropicalis ATCC 750).
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Affiliation(s)
- Manjit Singh
- Department of Chemistry, IIT (BHU) Varanasi India
| | | | - Vijay B Yadav
- Department of Chemistry, University of Allahabad India
| | | | - Munesh Gupta
- Department of Microbiology, IMS(BHU) Varanasi India
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2
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Samanta S, Kumar S, Aratikatla EK, Ghorpade SR, Singh V. Recent developments of imidazo[1,2- a]pyridine analogues as antituberculosis agents. RSC Med Chem 2023; 14:644-657. [PMID: 37122538 PMCID: PMC10131611 DOI: 10.1039/d3md00019b] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Over the past 2000 years, tuberculosis (TB) has killed more people than any other infectious disease. In 2021, TB claimed 1.6 million lives worldwide, making it the second leading cause of death from an infectious disease after COVID-19. Unfortunately, TB drug discovery research was neglected in the last few decades of the twentieth century. Recently, the World Health Organization has taken the initiative to develop new TB drugs. Imidazopyridine, an important fused bicyclic 5,6 heterocycle has been recognized as a "drug prejudice" scaffold for its wide range of applications in medicinal chemistry. A few examples of imidazo[1,2-a]pyridine exhibit significant activity against multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Here, we critically review anti-TB compounds of the imidazo[1,2-a]pyridine class by discussing their development based on the structure-activity relationship, mode-of-action, and various scaffold hopping strategies over the last decade, which is identified as a renaissance era of TB drug discovery research.
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Affiliation(s)
- Sauvik Samanta
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Sumit Kumar
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Eswar K Aratikatla
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Sandeep R Ghorpade
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Vinayak Singh
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Institute of Infectious Disease and Molecular Medicine, University of Cape Town Rondebosch 7701 South Africa
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3
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Danel A, Gondek E, Kucharek M, Szlachcic P, Gut A. 1 H-Pyrazolo[3,4- b]quinolines: Synthesis and Properties over 100 Years of Research. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092775. [PMID: 35566124 PMCID: PMC9099536 DOI: 10.3390/molecules27092775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/13/2022] [Accepted: 04/22/2022] [Indexed: 12/12/2022]
Abstract
This paper summarises a little over 100 years of research on the synthesis and the photophysical and biological properties of 1H-pyrazolo[3,4-b]quinolines that was published in the years 1911–2021. The main methods of synthesis are described, which include Friedländer condensation, synthesis from anthranilic acid derivatives, multicomponent synthesis and others. The use of this class of compounds as potential fluorescent sensors and biologically active compounds is shown. This review intends to summarize the abovementioned aspects of 1H-pyrazolo[3,4-b]quinoline chemistry. Some of the results that are presented in this publication come from the laboratories of the authors of this review.
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Affiliation(s)
- Andrzej Danel
- Faculty of Materials Engineering and Physics, Cracow University of Technology, Podchorążych Str. 1, 30-084 Krakow, Poland;
- Correspondence:
| | - Ewa Gondek
- Faculty of Materials Engineering and Physics, Cracow University of Technology, Podchorążych Str. 1, 30-084 Krakow, Poland;
| | - Mateusz Kucharek
- Faculty of Food Technology, University of Agriculture in Krakow, Balicka Str. 122, 30-149 Krakow, Poland; (M.K.); (P.S.)
| | - Paweł Szlachcic
- Faculty of Food Technology, University of Agriculture in Krakow, Balicka Str. 122, 30-149 Krakow, Poland; (M.K.); (P.S.)
| | - Arkadiusz Gut
- Faculty of Chemistry, Jagiellonian University, Gronostajowa Str. 2, 30-387 Krakow, Poland;
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4
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Singh R, Kumar R, Kaur M, Patil MT, Sahoo SC, Salunke DB. Groebke–Blackburn–Bienaymé
multicomponent reaction coupled with unconventional
Pictet–Spengler
cyclization for the synthesis of imidazo[4,5‐
b
]pyridine fused polycyclic heterocycles. J Heterocycl Chem 2022. [DOI: 10.1002/jhet.4438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Rahul Singh
- Department of Chemistry and Centre of Advanced Studies in Chemistry Panjab University Chandigarh India
| | - Ravinder Kumar
- Department of Chemistry and Centre of Advanced Studies in Chemistry Panjab University Chandigarh India
| | - Manpreet Kaur
- Department of Chemistry and Centre of Advanced Studies in Chemistry Panjab University Chandigarh India
| | - Madhuri T. Patil
- Department of Chemistry Mehr Chand Mahajan DAV College for Women Chandigarh India
| | - Subash Chandra Sahoo
- Department of Chemistry and Centre of Advanced Studies in Chemistry Panjab University Chandigarh India
| | - Deepak B. Salunke
- Department of Chemistry and Centre of Advanced Studies in Chemistry Panjab University Chandigarh India
- National Interdisciplinary Centre of Vaccine, Immunotherapeutics and Antimicrobials Panjab University Chandigarh India
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5
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Gernet A, Sevrain N, Volle JN, Ayad T, Pirat JL, Virieux D. Diversity-Oriented Synthesis toward Aryl- and Phosphoryl-Functionalized Imidazo[1,2- a]pyridines. J Org Chem 2020; 85:14730-14743. [PMID: 33166470 DOI: 10.1021/acs.joc.0c02059] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report herein an efficient synthesis of diversely polysubstituted imidazo[1,2-a]pyridines, a family of aza-heterocycles endowed with numerous biological properties, through a sequence involving two consecutive palladium-catalyzed cross-coupling reactions. First, we demonstrated that a Hirao coupling occurred straightforwardly in high yields at positions 3, 5, and 6 of imidazopyridine derivatives, giving access to a wide variety of substituted phosphonates, phosphinates, and phosphine oxides. In a second step, direct CH-arylation of phosphorylimidazopyridines with aryl halides was found to be effective and fully selective, leading to 3-aryl-substituted imidazopyridines in moderate to high yields depending on steric hindrance.
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Affiliation(s)
- Aurélie Gernet
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34296 Montpellier, France
| | - Nicolas Sevrain
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34296 Montpellier, France
| | - Jean-Noël Volle
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34296 Montpellier, France
| | - Tahar Ayad
- PSL University, Chimie ParisTech, CNRS, Institute of Chemistry for Life and Health Sciences, CSB2D Team, 11 rue Pierre et Marie Curie, 75005 Paris, France
| | - Jean-Luc Pirat
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34296 Montpellier, France
| | - David Virieux
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34296 Montpellier, France
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6
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Abd-Elmonem M, A. Mekheimer R, M. Hayallah A, A. Abo Elsoud F, U. Sadek K. Recent Advances in the Utility of Glycerol as a Benign and Biodegradable Medium in Heterocyclic Synthesis. CURR ORG CHEM 2020. [DOI: 10.2174/1385272823666191025150646] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
:
Glycerol is a non-toxic, recyclable and biodegradable organic waste produced
as a byproduct in the production of biodiesel fuel. Currently, glycerol is considered
a green solvent and catalyst for a large variety of applications. This work discusses
the significance of glycerol for heterocyclic synthesis. All the reported studies
consider glycerol as an efficient and sustainable benign medium.
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Affiliation(s)
- Mohamed Abd-Elmonem
- Department of Chemistry, Faculty of Science, Minia University, Minia 61519, Egypt
| | - Ramadan A. Mekheimer
- Department of Chemistry, Faculty of Science, Minia University, Minia 61519, Egypt
| | - Alaa M. Hayallah
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Deraya University, Minia, Egypt
| | - Fatma A. Abo Elsoud
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Deraya University, Minia, Egypt
| | - Kamal U. Sadek
- Department of Chemistry, Faculty of Science, Minia University, Minia 61519, Egypt
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7
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Dutta NB, Sharma S, Chetry RL, Baishya G. A Green Protocol for the Synthesis of
α
‐Diazo‐
β
‐hydroxyesters and One‐Pot Conversion to
β
‐Keto‐Esters and Imidazo[1,2‐
a
]pyridine‐3‐carboxylates. ChemistrySelect 2019. [DOI: 10.1002/slct.201900872] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Nibedita Baruah Dutta
- Natural Products Chemistry Group, Chemical Science & Technology DivisionCSIR-North East Institute of Science and Technology Jorhat 785006 India
- Rain Forest Research Institute Jorhat 785001
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad Uttar Pradesh 201002 India
| | - Suraj Sharma
- Natural Products Chemistry Group, Chemical Science & Technology DivisionCSIR-North East Institute of Science and Technology Jorhat 785006 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad Uttar Pradesh 201002 India
| | - Rudra Lal Chetry
- Natural Products Chemistry Group, Chemical Science & Technology DivisionCSIR-North East Institute of Science and Technology Jorhat 785006 India
| | - Gakul Baishya
- Natural Products Chemistry Group, Chemical Science & Technology DivisionCSIR-North East Institute of Science and Technology Jorhat 785006 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad Uttar Pradesh 201002 India
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8
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Tufail F, Singh S, Saquib M, Tiwari J, Singh J, Singh J. Catalyst-Free, Glycerol-Assisted Facile Approach to Imidazole-Fused Nitrogen-Bridgehead Heterocycles. ChemistrySelect 2017. [DOI: 10.1002/slct.201700557] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Fatima Tufail
- Environmentally Benign Synthesis Lab, Department of Chemistry; University of Allahabad; Allahabad- 211002 India
| | - Swastika Singh
- Environmentally Benign Synthesis Lab, Department of Chemistry; University of Allahabad; Allahabad- 211002 India
| | - Mohammad Saquib
- Environmentally Benign Synthesis Lab, Department of Chemistry; University of Allahabad; Allahabad- 211002 India
| | - Jyoti Tiwari
- Environmentally Benign Synthesis Lab, Department of Chemistry; University of Allahabad; Allahabad- 211002 India
| | - Jaya Singh
- Department of Chemistry; LRPG College; Sahibabad, Uttar Pradesh India
| | - Jagdamba Singh
- Environmentally Benign Synthesis Lab, Department of Chemistry; University of Allahabad; Allahabad- 211002 India
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9
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The behavioral pharmacology of zolpidem: evidence for the functional significance of α1-containing GABA(A) receptors. Psychopharmacology (Berl) 2014; 231:1865-96. [PMID: 24563183 DOI: 10.1007/s00213-014-3457-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/11/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a positive allosteric modulator of γ-aminobutyric acid (GABA) with preferential binding affinity and efficacy for α1-subunit containing GABA(A) receptors (α1-GABA(A)Rs). Over the last three decades, a variety of animal models and experimental procedures have been used in an attempt to relate the behavioral profile of zolpidem and classic benzodiazepines (BZs) to their interaction with α1-GABA(A)Rs. OBJECTIVES This paper reviews the results of rodent and non-human primate studies that have evaluated the effects of zolpidem on motor behaviors, anxiety, memory, food and fluid intake, and electroencephalogram (EEG) sleep patterns. Also included are studies that examined zolpidem's discriminative, reinforcing, and anticonvulsant effects as well as behavioral signs of tolerance and withdrawal. RESULTS The literature reviewed indicates that α1-GABA(A)Rs play a principle role in mediating the hypothermic, ataxic-like, locomotor- and memory-impairing effects of zolpidem and BZs. Evidence also suggests that α1-GABA(A)Rs play partial roles in the hypnotic, EEG sleep, anticonvulsant effects, and anxiolytic-like of zolpidem and diazepam. These studies also indicate that α1-GABA(A)Rs play a more prominent role in mediating the discriminative stimulus, reinforcing, hyperphagic, and withdrawal effects of zolpidem and BZs in primates than in rodents. CONCLUSIONS The psychopharmacological data from both rodents and non-human primates suggest that zolpidem has a unique pharmacological profile when compared with classic BZs. The literature reviewed here provides an important framework for studying the role of different GABA(A)R subtypes in the behavioral effects of BZ-type drugs and helps guide the development of new pharmaceutical agents for disorders currently treated with BZ-type drugs.
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10
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Abstract
Drug discrimination has been an important technique in behavioural pharmacology for at least 40 years. The characteristics of drug-produced discriminative stimuli are influenced by behavioural and pharmacological variables, including the doses used to establish discriminations. This review covers studies on the effects of varying the training dose of a drug in a search for general principles that are applicable across different drug classes and methodological approaches. With respect to quantitative changes, relationships between training dose and the rate of acquisition or magnitude of stimulus control were found for most drug classes. Acquisition accelerated with dose up to a point beyond which drug-induced impairments of performance had a deleterious impact. Sensitivity to the training drug as measured by ED(50) values typically increased when the training dose was reduced. Qualitative changes were more complex and appeared to fall into three categories: (a) changes in profiles of generalization between partial and full agonists; (b) reduced specificity of some discriminations at small training doses; and (c) changes in the relative salience of actions mediated through different neurotransmitter systems or from central and peripheral sites. Three-lever discrimination procedures incorporating 'drug versus drug' or 'dose versus dose' contingencies enabled detection of more subtle differences than the simple 'drug versus no drug' approach when applied to the opioid, hallucinogen and barbiturate classes of drugs. These conclusions have implications for the interpretation of data from studies that use either within-subject or between-subject designs for studying the discriminative stimulus effects of drugs.
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11
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Abstract
Zaleplon is a chemically novel hypnotic that preferentially binds alpha(1)-subunit containing subtypes of the alphabetagamma configuration of the gamma-aminobutyric acid (GABA)(A) receptor. Zaleplon and the non-subtype-selective hypnotic triazolam occasioned 100% drug-appropriate responding in baboons trained to discriminate lorazepam or pentobarbital from vehicle. Flumazenil shifted the zaleplon generalization gradient at least five-fold to the right. A plasma elimination half-life of 6-8 h for oral 10 mg/kg zaleplon and 0.32 mg/kg triazolam was paralleled by discriminative control for 7 h. Zaleplon maintained self-injection greater than vehicle, as did comparison doses of the similarly selective hypnotic zolpidem and triazolam. Concurrent food-maintained responding increased during self-injection of all three drugs. Preferential binding at this alpha(1)-containing GABA(A) subtype did not diminish the benzodiazepine (Bzs)-like behavioral effects of zaleplon.
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Affiliation(s)
- N A Ator
- Behavioral Biology Research Center, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, John Hopkins Bayview Campus, 5510 Nathan Shock Drive Ste 3000, Baltimore, MD, 21224-6823, USA.
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12
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Vanover KE. Effects of benzodiazepine receptor ligands and ethanol in rats trained to discriminate pregnanolone. Pharmacol Biochem Behav 2000; 67:483-7. [PMID: 11164076 DOI: 10.1016/s0091-3057(00)00394-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Although GABA(A) receptor positive modulators share many behavioral effects, subtle differences have been detected among their discriminative stimulus effects. The purpose of the present study was to determine the extent of shared discriminative stimulus effects of pregnanolone with various benzodiazepine receptor ligands and with ethanol. Naive male Sprague-Dawley rats were trained to discriminate the endogenous neuroactive steroid pregnanolone (5.6 or 8.0 mg/kg) from vehicle. The benzodiazepine receptor agonists, triazolam and lorazepam, the benzodiazepine receptor partial agonist, bretazenil, the benzodiazepine1 (BZ1) receptor subtype selective agonists, zolpidem and zaleplon and ethanol were tested. Triazolam, lorazepam and bretazenil substituted for pregnanolone. Lorazepam, but not triazolam or bretazenil, decreased response rates at the highest dose tested. Zaleplon completely substituted for pregnanolone with no effect on response rates. Zolpidem substituted for pregnanolone only at a dose that severely disrupted response rates. Ethanol partially substituted for pregnanolone and decreased response rates. The results are consistent with GABA(A) receptor mediation of the discriminative stimulus effects of pregnanolone. The effects on response rates suggest subtle differentiation among the GABA(A) receptor-mediated cues.
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13
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Sanger DJ, Griebel G, Perrault G, Claustre Y, Schoemaker H. Discriminative stimulus effects of drugs acting at GABA(A) receptors: differential profiles and receptor selectivity. Pharmacol Biochem Behav 1999; 64:269-73. [PMID: 10515302 DOI: 10.1016/s0091-3057(99)00081-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The GABA(A) receptor complex contains a number of binding sites at which a variety of psychotropic drugs, including benzodiazepines, barbiturates, and some neurosteroids, act to potentiate or inhibit the effect of the transmitter. Many studies have reported that these drugs can produce discriminative stimulus actions, but the cueing effects of compounds acting at different sites to enhance the effects of GABA are not identical. The discriminative stimulus effects of benzodiazepines have been analyzed in detail, and there is also a great deal of information available on the effects of nonbenzodiazepine compounds acting at BZ(omega) recognition sites, which form part of the GABA(A) receptor complex. Of particular interest are compounds with selectivity for the BZ1(omega1) receptor subtype including zolpidem, zaleplon, and CI 218,872. BZ1(omega1)-selective drugs substitute for the discriminative stimulus produced by chlordiazepoxide only partially and at sedative doses. This is consistent with the view that sedative effects of BZ(omega) receptor agonists are mediated by the BZ1(omega1) receptor subtype, whereas the discriminative stimulus produced by chlordiazepoxide may be produced by activity at the BZ2(omega2) subtype. Analysis of this hypothesis is complicated by the variety of levels of intrinsic activity shown by different drugs.
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14
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Griebel G, Perrault G, Tan S, Schoemaker H, Sanger DJ. Pharmacological studies on synthetic flavonoids: comparison with diazepam. Neuropharmacology 1999; 38:965-77. [PMID: 10428415 DOI: 10.1016/s0028-3908(99)00026-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The present experiments compared the central BZ-omega binding characteristics and pharmacological profiles of two synthetic flavonoids (6-bromoflavone and 6-bromo-3'-nitroflavone) with those of the benzodiazepine (BZ) diazepam. In vitro experiments showed that while diazepam displaced [3H]flumazenil binding to the GABA(A) receptor in membranes from rat cerebellum and spinal cord, two brain areas enriched in the BZ-omega1 and BZ-omega2 receptor subtypes, with nearly equivalent half maximally effective concentrations, 6-bromo-3'-nitroflavone was somewhat more potent in displacing [3H]flumazenil binding to membranes from rat cerebellum (IC50 = 31 nM) than from spinal cord (IC50 = 120 nM), indicating selectivity for the BZ-omega1 receptor subtype. 6-Bromoflavone displayed weak (IC50 = 970 nM) affinity for the BZ-omega1 and no affinity for the BZ-omega2 (IC50 > 1000 nM) receptor subtypes. Diazepam, but not the synthetic flavonoids increased the latency to clonic seizures produced by isoniazid, thereby indicating that neither 6-bromoflavone nor 6-bromo-3'-nitroflavone display detectable intrinsic activity at GABA(A) receptors in vivo. Results from two conflict tests in rats showed that 6-bromoflavone (3-10 mg/kg) and 6-bromo-3'-nitroflavone (0.3-1 mg/kg) elicited anxiolytic-like activity in the punished drinking test, while both drugs were inactive in the punished lever pressing test. The positive effects displayed by the synthetic flavonoids in the punished drinking procedure were smaller than that of diazepam and were not antagonized by the BZ receptor antagonist flumazenil. In two models of exploratory activity, 6-bromoflavone (3-30 mg/kg) and 6-bromo-3'-nitroflavone (0.3-1 mg/kg) produced anxiolytic-like effects in the rat elevated plus-maze test, whereas both compounds failed to modify the behavior of mice in the light/dark test over a wide dose-range. The effects in the elevated plus-maze were antagonized by flumazenil. In the mouse defense test battery, where mice were confronted with a natural threat (a rat), 6-bromoflavone and 6-bromo-3'-nitroflavone failed to decrease flight reactions after the rat was introduced into the test area and risk assessment behavior displayed when subjects were constrained in a straight alley, and only weakly affected risk assessment of mice chased by the rat and defensive biting upon forced contact with the threat stimulus. In a drug discrimination experiment 6-bromoflavone and 6-bromo-3'-nitroflavone up to 30 and 3 mg/kg, respectively, did not substitute for the BZ chlordiazepoxide. Taken together, these results failed to demonstrate that the synthetic flavonoids 6-bromoflavone and 6-bromo-3'-nitroflavone possess anxiolytic-like properties similar or superior to that of diazepam, as was suggested previously. Furthermore, they question the contribution of BZ-omega receptors to the behavioral effects of 6-bromoflavone and 6-bromo-3'-nitroflavone.
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Affiliation(s)
- G Griebel
- CNS Research Department, Synthélabo Recherche, Bagneux, France.
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15
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Kostowski W, Bieńkowski P. Discriminative stimulus effects of ethanol: neuropharmacological characterization. Alcohol 1999; 17:63-80. [PMID: 9895039 DOI: 10.1016/s0741-8329(98)00035-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Generally, compounds discriminated by animals possess psychotropic effects in animals and humans. As with many other drugs of abuse, strength of the ethanol discriminative stimulus is dose related. The majority of studies show that doses close to 1.0 g/kg are close to the minimum at which the discrimination can be learned easily. Substitution studies suggest that anxiolytic, sedative, atactic, and myorelaxant effects of ethanol all play an important role in the formation of its intercoeptive stimulus. Low doses of ethanol produce more excitatory cues, similar to amphetamine-like subjective stimuli, whereas higher doses produce rather sedative/hypnotic stimuli similar to those elicited by barbiturates. Substitution studies have shown that the complete substitution for ethanol may be exerted by certain GABA-mimetic drugs acting through different sites within the GABA(A)-benzodiazepine receptor complex (e.g., diazepam, pentobarbital, certain neurosteroids), gamma-hydroxybutyrate, and antagonists of the glutamate NMDA receptor. Among the NMDA receptor antagonists both noncompetitive (e.g., dizocilpine) and competitive antagonists (e.g., CGP 40116) are capable of substituting for ethanol. Further, some antagonists of strychnine-insensitive glycine modulatory sites among the NMDA receptor complex (e.g., L-701,324) dose-dependently substitute for the ethanol discriminative stimulus. On the other hand, neither GABA-benzodiazepine antagonists nor NMDA receptor agonists produce contradictory effects (i.e., reduce the ethanol discriminative stimulus). There is influence of a particular training dose of ethanol on the substitution pattern of different compounds. For example, 5-HT(1B/2C) agonists substitute for intermediate (1.0 g/kg) but not higher (2.0 g/kg) ethanol training doses. Discrimination studies with ethanol and drugs acting on NMDA and GABA receptors consistently indicate asymmetrical generalization. For example, ethanol is able to generalize to barbiturates and benzodiazepines, but neither the benzodiazepine nor barbiturate response generalizes to ethanol. Only a few drugs are able to antagonize, at least to some extent, the discriminative stimulus of ethanol (e.g., partial inverse GABA-benzodiazepine receptor antagonist Ro 15-4513 and the opioid antagonist naloxone). The ethanol stimulus effect may be increased (i.e., stronger recognition) by N-cholinergic drugs (nicotine), dopaminergic drugs (apomorphine), and 5-HT3 receptor agonists (m-chlorophenylbiguanide). Thus, the ethanol stimulus is composed of the several components, with the NMDA receptor and GABA(A) receptor complex being of particular importance. This suggests that a drug mixture may be more capable of substituting for ethanol (or block its stimulus) than a single compound. The ability of drugs to substitute for the ethanol discriminative stimulus is frequently, although not preclusively, associated with the reduction of voluntary ethanol consumption. The examples of positive correlation are gamma-hydroxybutyrate, possibly memantine and certain serotonergic drugs such as fluoxetine. However, it remains uncertain to what extent the discriminative stimulus of ethanol can be seen as relevant in the understanding of the complex mechanisms of dependence.
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Affiliation(s)
- W Kostowski
- Department of Pharmacology & Physiology of the Nervous System, Institute of Psychiatry & Neurology, Warsaw, Poland
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16
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Bienkowski P, Iwinska K, Stefanski R, Kostowski W. Discriminative stimulus properties of ethanol in the rat: differential effects of selective and nonselective benzodiazepine receptor agonists. Pharmacol Biochem Behav 1997; 58:969-73. [PMID: 9408202 DOI: 10.1016/s0091-3057(97)00034-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Rats were trained to discriminate between ethanol (1.0 g/kg; 10% v/v) and saline under a fixed ratio 10 schedule of sweetened milk reinforcement. Both diazepam [nonselective, full benzodiazepine (BZ) receptors agonist] and bretazenil (nonselective, partial BZ receptor agonist) produced dose-dependent ethanol-appropriate responding (>75%). Neither diazepam nor bretazenil affected the response rate at the doses producing maximal generalisation from ethanol. In contrast, zolpidem (full BZ1 receptor agonist) and abecarnil (full BZ1/full or partial BZ2 receptor agonist) produced only moderate (<50%) ethanol-appropriate responding when tested up to doses that markedly decreased the overall response rate. These results suggest that: 1) there are no major differences between full and partial, nonselective BZ receptor agonists in their ability to substitute for 1.0 g/kg dose of ethanol; 2) stimulation of BZ1 receptors alone is not sufficient to produce ethanol-like discriminative stimulus effects in the rat.
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Affiliation(s)
- P Bienkowski
- Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, Warsaw, Poland
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17
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Bronson M, Chen HC. Time course of discriminative stimulus effects of bretazenil and chlordiazepoxide in rats. Eur J Pharmacol 1996; 305:7-12. [PMID: 8813525 DOI: 10.1016/0014-2999(96)00116-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The time course of the discriminative stimulus effects of a benzodiazepine partial agonist, bretazenil, and a benzodiazepine full agonist, chlordiazepoxide, were determined in rats after administration of two doses of either drug. As in man, bretazenil was considerably shorter-acting than chlordiazepoxide, with 0% drug-appropriate responding at the 2-h time point after the training dose of 7 mg/kg and < 20% drug-appropriate responding at 9 h after the 14 mg/kg dose. With chlordiazepoxide, responding on the water-appropriate lever did not occur in all rats until 7 h after administration of the training dose of 7 mg/kg, compared to 17 h after administration of 14 mg/kg. Although there was considerable individual variability with both drugs, it would appear that the drug discrimination procedure can be a valuable tool for studying the time course of the interoceptive effects of psychoactive drugs.
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Affiliation(s)
- M Bronson
- Department of Pharmacal Sciences, Auburn University, AL 36849-5503, USA.
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18
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Patat A, Perault MC, Vandel B, Danjou P, Brohier S, Zieleniuk I, Rosenzweig P. Assessment of the interaction between a partial agonist and a full agonist of benzodiazepine receptors, based on psychomotor performance and memory, in healthy volunteers. J Psychopharmacol 1995; 9:91-101. [PMID: 22298734 DOI: 10.1177/026988119500900203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Potential interactions between the imidazopyridine anxiolytic alpidem and the full benzodiazepine agonist lorazepam were assessed in a randomized, double-blind, four-way cross-over, placebo-controlled study in 16 healthy young male volunteers. Each volunteer received alpidem, 50 mg, or a placebo twice daily for 8 days with a 1- week wash-out interval. The interaction between alpidem, at the steady state, and a single oral dose of lorazepam 2 mg or a placebo was assessed after concomitant administration on days 7 or 9 of each treatment period. Psycho motor performance and cognitive function were evaluated before and 2, 4, 6 and 8 h post-dose, using objective tests [critical flicker fusion threshold (CFF), choice reaction time (CRT), digit-symbol substitution (DSST), body sway and short-term memory (Sternberg memory scanning)] and self-ratings [line analogue rating scales: (LARS)]. Long-term memory (delayed free recall and recognition of pictures) was assessed before the dose and 2 and 4 h post-dose. Pharmacodynamic interactions were evaluated by applying repeated measures ANOVA to a 2 x 2 factorial interaction model. Alpidem, 50 mg twice daily at the steady state, was free of any clinically relevant detrimental effects on skilled performance, information processing or memory. In contrast, a single 2 mg dose of lorazepam induced marked impairment of psychomotor performance and cognitive function (significant reductions in CFF and DSST and increases in CRT and body sway), as well as subjective sedation from 2 to 8 h post-dose, depending on the test used. In addition, lorazepam induced anterograde amnesia, characterized by a decrease in delayed free recall and recognition, and a deficit in short-term memory. Finally, alpidem 50 mg did not potentiate the detrimental effects of lorazepam 2 mg. On the contrary, alpidem significantly antagonized the lorazepam-induced CRT increase and anterograde amnesia, and produced similar trends on most of the other cognitive parameters; thus, the results obtained with the combination of alpidem and lorazepam consistently indicated less impairment than those measured after lorazepam alone. These results are consistent with the suggested partial agonsist properties of alpidem at the benzodiazepine receptor and indicate that such properties can be assessed in humans based on antagonism of the effects of a full agonist.
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Affiliation(s)
- A Patat
- Synthélabo Recherche, Clinical Research Department, Clinical Pharmacology Section, 31, Av. Paul Vaillant Couturier, B. P. 110, 92225 Bagneux Cedex
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19
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Sanger DJ, Benavides J, Perrault G, Morel E, Cohen C, Joly D, Zivkovic B. Recent developments in the behavioral pharmacology of benzodiazepine (omega) receptors: evidence for the functional significance of receptor subtypes. Neurosci Biobehav Rev 1994; 18:355-72. [PMID: 7984354 DOI: 10.1016/0149-7634(94)90049-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Recent research in molecular biology has demonstrated the complexity of GABAA receptors and shown that benzodiazepine (BZ-omega) receptor subtypes have a structural reality. It is therefore appropriate to ask whether the different pharmacological effects produced by benzodiazepines (anticonvulsant activity, anxiety reduction, motor incoordination, learning deficits, characteristic discriminative stimulus effects, tolerance and dependence) are associated with activity at different receptor subtypes. The present paper reviews the literature dealing with the behavioral effects of novel BZ (omega) receptor ligands relevant to the question of the functional significance of the BZ1 (omega 1) and BZ2 (omega 2) receptor subtypes. The only drugs currently available with a considerable degree of selectivity are alpidem and zolpidem. These compounds have relatively high affinity for GABAA receptors containing the alpha 1 subunit (corresponding to the BZ1 (omega 1) subtype) and very low affinity for receptors with the alpha 5 subunit (corresponding to one type of BZ2 (omega 2) receptor). Pharmacological effects observed with these, and other, less selective compounds allow several tentative conclusions to be drawn: (a) Little is known of the role of subtype selectivity in anxiolytic or amnestic effects but compounds with low intrinsic activity may reduce anxiety without giving rise to sedation or motor incoordination and BZ1 (omega 1) selective drugs appear to disrupt memory only at sedative doses; (b) Selectivity for BZ1 (omega 1) receptors may be associated with sleep-inducing activity but not with motor incoordination, suggesting that BZ2 (omega 2) receptors may be of particular importance in mechanisms of muscle relaxation; (c) The discriminative stimulus effects of different BZ (omega) receptor ligands are not identical and differences may be related to receptor selectivity; (d) Compounds with BZ1 (omega 1) selectivity and compounds with low intrinsic activity produce little or no tolerance and dependence. A wider range of selective compounds will be necessary to investigate these factors in detail and many different pharmacological profiles can be expected from drugs with selectivity and different levels of intrinsic activity.
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Affiliation(s)
- D J Sanger
- Synthélabo Recherche (L.E.R.S.), Bagneux, France
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