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Kim SK, Goddard III WA. Molecular-Docking-Based Drug Design and Discovery. PHARMACEUTICAL SCIENCES 2017. [DOI: 10.4018/978-1-5225-1762-7.ch025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Currently 30-50% of drug targets are G Protein-Coupled Receptors (GPCRs). However, the clinical useful drugs for targeting GPCR have been limited by the lack of subtype selectivity or efficacy, leading to undesirable side effects. To develop subtype-selective GPCR ligands with desired molecular properties, better understanding is needed of the pharmacophore elements and of the binding mechanism required for subtype selectivity. To illustrate these issues, we describe here three successful applications to understand the binding mechanism associated with subtype selectivity: 5-HT2B (5-Hydroxytryptamine, 5-HT) serotonin receptor (HT2BR), H3 histamine receptor (H3HR) and A3 adenosine receptor (A3AR). The understanding of structure-function relationships among individual types and subtypes of GPCRs gained from such computational predictions combined with experimental validation and testing is expected the development of new highly selective and effective ligands to address such diseases while minimizing side-effects.
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2
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Shahsavar A, Gajhede M, Kastrup JS, Balle T. Structural Studies of Nicotinic Acetylcholine Receptors: Using Acetylcholine-Binding Protein as a Structural Surrogate. Basic Clin Pharmacol Toxicol 2016; 118:399-407. [DOI: 10.1111/bcpt.12528] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/02/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Azadeh Shahsavar
- Department of Molecular Biology and Genetics; Danish Research Institute of Translational Neuroscience - DANDRITE; Aarhus University; Aarhus Denmark
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Michael Gajhede
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Jette S. Kastrup
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Thomas Balle
- Faculty of Pharmacy; The University of Sydney; Sydney NSW Australia
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3
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Lippiello P, Bencherif M, Hauser T, Jordan K, Letchworth S, Mazurov A. Nicotinic receptors as targets for therapeutic discovery. Expert Opin Drug Discov 2015; 2:1185-203. [PMID: 23496128 DOI: 10.1517/17460441.2.9.1185] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) represent a class of therapeutic targets with the potential to impact numerous diseases and disorders where significant unmet medical needs remain. The latter include cognitive and neurodegenerative diseases; psychotic disorders, such as schizophrenia; acute nociceptive, neuropathic and inflammatory pain; affective disorders, such as depression and inflammation, where nAChR subtypes modulate key cellular pathways involved in anti-inflammatory processes as well as cell survival. Our increased understanding of the heterogeneity of nAChR targets is defining the relationship of biologic effects to specific receptor subtypes, which in turn, will allow further refinement of desired therapeutic activities. Both preclinical and clinical evidence support the notion that novel compounds targeting specific nAChR subtypes will offer increased potency and efficacy, longer lasting effects, fewer side effects and a more rapid onset of action and less dependence, compared with existing therapies. Clinical proof-of-concept is rapidly emerging and will solidify the position of this new therapeutic approach.
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Affiliation(s)
- Pm Lippiello
- Targacept, Inc., 200 East 1st Street, Suite 300, Winston-Salem, NC 27101, USA +1 336 480 2100 ; +1 336 480 2107 ;
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4
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Sepsova V, Krusek J, Zdarova Karasova J, Zemek F, Musilek K, Kuca K, Soukup O. The interaction of quaternary reversible acetylcholinesterase inhibitors with the nicotinic receptor. Physiol Res 2014; 63:771-7. [PMID: 25157661 DOI: 10.33549/physiolres.932768] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Acetylcholinesterase inhibitors (AChEIs) are used in the treatment of myasthenia gravis (MG). We investigated the effects of AChEIs on peripheral nicotinic receptors (nAChR), which play a crucial role in the treatment of MG symptoms. The positive modulation of those receptors by AChE inhibitors could have an added value to the anti-AChE activity and might be useful in the therapy of MG. Furthermore, to estimate the potential drawbacks of the compounds, cytotoxicity has been assessed on various cell lines. The whole-cell mode of the patch-clamp method was employed. The experiments were performed on medulloblastoma/rhabdomyosarcoma cell line TE671 expressing human embryonic muscle-like receptor with subunits alpha2betagammadelta. The effect of the compounds on cell viability was measured by standard MTT assay (Sigma Aldrich) on ACHN (renal cell adenocarcinoma), HeLa (immortal cell line derived from a cervical carcinoma), HEPG2 (hepatocellular carcinoma) and BJ (skin fibroblasts) cell lines. No positive modulation by the tested AChE inhibitors was observed. Moreover, the compounds exhibited antagonistic activity on the peripheral nAChR. Standard drugs used in MG treatment were shown to be less potent inhibitors of muscle-type nAChR than the newly synthesized compounds. The new compounds showed very little effect on cell viability, and toxicities were comparable to standards. Newly synthesized AChEIs inhibited peripheral nAChR. Furthermore, the inhibition was higher than that of standards used for the treatment of MG. They could be used for the study of nAChR function, thanks to their high antagonizing potency and fast recovery of receptor activity after their removal. However, since no positive modulation was observed, the new compounds do not seem to be promising candidates for MG treatment, even though their cytotoxic effect was relatively low.
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Affiliation(s)
- V Sepsova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic, Biomedical Research Center, Hradec Kralove, Czech Republic.
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5
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Zemkova H, Kucka M, Bjelobaba I, Tomic M, Stojilkovic SS. Multiple cholinergic signaling pathways in pituitary gonadotrophs. Endocrinology 2013; 154:421-33. [PMID: 23161872 PMCID: PMC3529387 DOI: 10.1210/en.2012-1554] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acetylcholine (ACh) has been established as a paracrine factor in the anterior pituitary gland, but the receptors mediating ACh action and the cell types bearing these receptors have not been identified. Our results showed that the expression of the nicotinic subunits mRNAs followed the order β2 > β1 = α9 > α4 in cultured rat pituitary cells. The expression of the subunits in immortalized LβT2 mouse gonadotrophs followed the order β2 > α4 = α1. M4 > M3 muscarinic receptor mRNA were also identified in pituitary and LβT2 cells. The treatment of cultured pituitary cells with GnRH down-regulated the expression of α9 and α4 mRNAs, without affecting the expression of M3 and M4 receptor mRNAs, and ACh did not alter the expression of GnRH receptor mRNA. We also performed double immunostaining to show the expression of β2-subunit and M4 receptor proteins in gonadotrophs. Functional nicotinic channels capable of generating an inward current, facilitation of electrical activity, and Ca(2+) influx were identified in single gonadotrophs and LβT2 cells. In both cell types, the M3 receptor-mediated, phospholipase C-dependent Ca(2+) mobilization activated an outward apamin-sensitive K(+) current and caused hyperpolarization. The activation of M4 receptors by ACh inhibited cAMP production and GnRH-induced LH release in a pertussis toxin-sensitive manner. We concluded that multiple cholinergic receptors are expressed in gonadotrophs and that the main secretory action of ACh is inhibitory through M4 receptor-mediated down-regulation of cAMP production. The expression of nicotinic receptors in vitro compensates for the lack of regular GnRH stimulation of gonadotrophs.
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Affiliation(s)
- Hana Zemkova
- Institute of Physiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic.
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6
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Nemecz Á, Taylor P. Creating an α7 nicotinic acetylcholine recognition domain from the acetylcholine-binding protein: crystallographic and ligand selectivity analyses. J Biol Chem 2011; 286:42555-42565. [PMID: 22009746 DOI: 10.1074/jbc.m111.286583] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Determining the structure of the ligand-binding domain of the nicotinic acetylcholine receptor (nAChR) has been a long standing goal in the design of selective drugs useful in implicated diseases for this prevalent receptor family. Acetylcholine-binding proteins have proven to be valuable surrogates with structural similarity and sequence identity to the extracellular domain of the nicotinic receptor, yet these soluble proteins have their unique features and do not serve as exact replicates of the nAChRs of interest. Here we systematically modify the sequence of these proteins toward the homomeric human α7 nAChR. These chimeric proteins exhibit a shift in affinities to reflect α7 binding characteristics yet maintain expression levels and stability conducive for crystallization. We also present a pentameric humanoid nAChR extracellular domain with the structural determination of the α7 nAChR glycosylation site.
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Affiliation(s)
- Ákos Nemecz
- Departments of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0650; Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0650.
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7
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Maier DL, Hill G, Ding M, Tuke D, Einstein E, Gurley D, Gordon JC, Bock MJ, Smith JS, Bialecki R, Eisman M, Elmore CS, Werkheiser JL. Pre-clinical validation of a novel alpha-7 nicotinic receptor radiotracer, [3H]AZ11637326: Target localization, biodistribution and ligand occupancy in the rat brain. Neuropharmacology 2011; 61:161-71. [DOI: 10.1016/j.neuropharm.2011.03.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 03/03/2011] [Accepted: 03/30/2011] [Indexed: 11/15/2022]
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8
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Zhang Z, Dwoskin LP, Crooks PA. Expeditious synthesis of cis-1-methyl-2, 3,3 a,4,5,9 b-hexahydro-1 H-pyrrolo-[3,2 h]isoquinoline / [2,3- f]quinoline via azomethine ylide-alkene [3+2] cycloaddition. Tetrahedron Lett 2011; 52:2667-2669. [PMID: 23908558 DOI: 10.1016/j.tetlet.2011.03.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Expeditious syntheses of cis-1-methyl-2,3,3a,4,5,9b-hexahydro-1H-pyrrolo-[3,2h]isoquinoline /[2,3-f]]quinoline have been developed. The syntheses started with commercially available material and afforded excellent overall yields in straightforward steps. Intramolecular azomethine ylide-alkene [3+2] cycloaddition is the key step in the construction of these pyrroloisoquinoline and pyrroloquinoline scaffolds. This route is much more atom-economic than those reported in the literature and appropriate for scale-up synthesis.
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Affiliation(s)
- Zhenfa Zhang
- College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
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9
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Grove CL, Szabo TM, McIntosh JM, Do SC, Waldeck RF, Faber DS. Fast synaptic transmission in the goldfish CNS mediated by multiple nicotinic receptors. J Physiol 2010; 589:575-95. [PMID: 21115642 DOI: 10.1113/jphysiol.2010.197608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Usually nicotinic receptors in the central nervous system only influence the strength of a signal between neurons. At a few critical connections, for instance some of those involved in the flight response, nicotinic receptors not only modulate the signal, they actually determine whether a signal is conveyed or not. We show at one of the few such connections accessible for study, up to three different nicotinic receptor subtypes mediate the signal. The subtypes appear to be clustered in separate locations. Depending on the number and combination of the subtypes present the signal can range from short to long duration and from low to high amplitude. This provides a critical connection with a built-in plasticity and may enable it to adapt to a changing environment.
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Affiliation(s)
- Charlotte L Grove
- Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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10
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Zaveri N, Jiang F, Olsen C, Polgar W, Toll L. Novel α3β4 nicotinic acetylcholine receptor-selective ligands. Discovery, structure-activity studies, and pharmacological evaluation. J Med Chem 2010; 53:8187-91. [PMID: 20979364 DOI: 10.1021/jm1006148] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antagonist activity at the α3β4 nicotinic acetylcholine receptor (nAChR) is thought to contribute to the antiaddictive properties of several compounds. However, truly selective ligands for the α3β4 nAChR have not been available. We report the discovery and SAR of a novel class of compounds that bind to the α3β4 nAChR and have no measurable affinity for the α4β2 or α7 subtype. In functional assays the lead compound antagonized epibatidine-induced Ca(2+) flux in α3β4-transfected cells in a noncompetitive manner.
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Affiliation(s)
- Nurulain Zaveri
- Biosciences Division, SRI International, 333 Ravenswood Avenue, Menlo Park, California 94025, USA.
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11
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Peng Y, Zhang Q, Snyder GL, Zhu H, Yao W, Tomesch J, Papke RL, O'Callaghan JP, Welsh WJ, Wennogle LP. Discovery of novel alpha7 nicotinic receptor antagonists. Bioorg Med Chem Lett 2010; 20:4825-30. [PMID: 20638843 PMCID: PMC3000800 DOI: 10.1016/j.bmcl.2010.06.103] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 06/16/2010] [Accepted: 06/21/2010] [Indexed: 11/20/2022]
Abstract
Two distinct families of small molecules were discovered as novel alpha7 nicotinic acetylcholine receptor (nAChR) antagonists by pharmacophore-based virtual screening. These novel antagonists exhibited selectivity for the neuronal alpha7 subtype over other nAChRs and good brain penetration. Neuroprotection was demonstrated by representative compounds 7i and 8 in a mouse seizure-like behavior model induced by the nerve agent diisopropylfluorophosphate (DFP). These novel nAChR antagonists have potential use as antidote for organophosphorus nerve agent intoxication.
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Affiliation(s)
- Youyi Peng
- Intra-Cellular Therapies, Inc., New York, NY, 10032, United States
| | - Qiang Zhang
- Intra-Cellular Therapies, Inc., New York, NY, 10032, United States
| | | | - Hongwen Zhu
- Intra-Cellular Therapies, Inc., New York, NY, 10032, United States
| | - Wei Yao
- Intra-Cellular Therapies, Inc., New York, NY, 10032, United States
| | - John Tomesch
- Intra-Cellular Therapies, Inc., New York, NY, 10032, United States
| | - Roger L. Papke
- Department of Pharmacology and Therapeutics, University of Florida, College of Medicine, Gainesville, FL 32610, United States
| | - James P. O'Callaghan
- Centers for Disease Control and Prevention-National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States
| | - William J. Welsh
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, United States
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12
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Huang LT, Sherwood JL, Sun YJ, Lodge D, Wang Y. Activation of presynaptic alpha7 nicotinic receptors evokes an excitatory response in hippocampal CA3 neurones in anaesthetized rats: an in vivo iontophoretic study. Br J Pharmacol 2010; 159:554-65. [PMID: 20105181 DOI: 10.1111/j.1476-5381.2009.00529.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE alpha7 Nicotinic receptors have been suggested to play an important role in hippocampal learning and memory. However, the direct action of this receptor subtype on hippocampal pyramidal neurones in vivo has not yet been fully investigated. The availability of selective agonists for alpha7 receptors [AR-R17779 and (R)-(-)-5'-phenylspiro[1-azabicyclo[2.2.2] octane-3,2'-(3'H)furo[2,3-b]pyridine (PSAB-OFP)] has now allowed this role to be investigated. EXPERIMENTAL APPROACH Single-cell extracellular recordings were made from hippocampal CA3 pyramidal neurones in anaesthetized rats. The effects of nicotine, AR-R17779 and PSAB-OFP, applied either systemically or iontophoretically, were studied on the activity of these neurones. KEY RESULTS Intravenous injection of cumulative doses of nicotine and PSAB-OFP induced dose-related, significant increases in neuronal firing in the majority of neurones tested. This excitation could be inhibited by intravenous administration of methyllycaconitine (MLA), a selective alpha7 nicotinic receptor antagonist. Furthermore, iontophoretic application of nicotine, AR-R17779 and PSAB-OFP each evoked current-dependent excitation of most CA3 pyramidal neurones studied, and this excitation was antagonized by co-iontophoretic application of MLA. In addition, the excitation induced by iontophoretic application of nicotine, AR-R17779 or PSAB-OFP was also blocked by co-iontophoretic application of either 6,7-dinitroquinoxaline-2,3-dione (DNQX) or D(2)-2-amino-5-phosphonopentanoate (D-AP5), selective N-methyl-D-aspartic acid (NMDA) and non-NMDA receptor antagonists respectively. CONCLUSIONS AND IMPLICATIONS CA3 pyramidal neurones are modulated by activation of presynaptic alpha7 nicotinic receptors, which, at least in part, enhances glutamate release onto post-synaptic (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid and NMDA receptors on these CA3 neurones. This mechanism probably contributes to the effects of nicotine on hippocampal learning and memory.
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Affiliation(s)
- Lan-Ting Huang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Fudan University, Shanghai, China
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13
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Hauser TA, Kucinski A, Jordan KG, Gatto GJ, Wersinger SR, Hesse RA, Stachowiak EK, Stachowiak MK, Papke RL, Lippiello PM, Bencherif M. TC-5619: an alpha7 neuronal nicotinic receptor-selective agonist that demonstrates efficacy in animal models of the positive and negative symptoms and cognitive dysfunction of schizophrenia. Biochem Pharmacol 2009; 78:803-12. [PMID: 19482012 DOI: 10.1016/j.bcp.2009.05.030] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 05/19/2009] [Accepted: 05/21/2009] [Indexed: 02/07/2023]
Abstract
A growing body of evidence suggests that the alpha7 neuronal nicotinic receptor (NNR) subtype is an important target for the development of novel therapies to treat schizophrenia, offering the possibility to address not only the positive but also the cognitive and negative symptoms associated with the disease. In order to probe the relationship of alpha7 function to relevant behavioral correlates we employed TC-5619, a novel selective agonist for the alpha7 NNR subtype. TC-5619 binds with very high affinity to the alpha7 subtype and is a potent full agonist. TC-5619 has little or no activity at other nicotinic receptors, including the alpha4beta2, ganglionic (alpha3beta4) and muscle subtypes. The transgenic th(tk-)/th(tk-) mouse model that reflects many of the developmental, anatomical, and multi-transmitter biochemical aspects of schizophrenia was used to assess the antipsychotic effects of TC-5619. In these mice TC-5619 acted both alone and synergistically with the antipsychotic clozapine to correct impaired pre-pulse inhibition (PPI) and social behavior which model positive and negative symptoms, respectively. Antipsychotic and cognitive effects of TC-5619 were also assessed in rats. Similar to the results in the transgenic mice, TC-5619 significantly reversed apomorphine-induced PPI deficits. In a novel object recognition paradigm in rats TC-5619 demonstrated long-lasting enhancement of memory over a wide dose range. These results suggest that alpha7-selective agonists such as TC-5619, either alone or in combination with antipsychotics, could offer a new approach to treating the constellation of symptoms associated with schizophrenia, including cognitive dysfunction.
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MESH Headings
- Animals
- Antipsychotic Agents/pharmacology
- Antipsychotic Agents/therapeutic use
- Behavior, Animal/drug effects
- Benzofurans/pharmacology
- Benzofurans/therapeutic use
- Clozapine/pharmacology
- Clozapine/therapeutic use
- Cognition Disorders/drug therapy
- Cognition Disorders/metabolism
- Cognition Disorders/psychology
- Exploratory Behavior/drug effects
- Female
- Male
- Maze Learning/drug effects
- Mice
- Mice, Transgenic
- Neurons/metabolism
- Nicotinic Agonists/pharmacology
- Nicotinic Agonists/therapeutic use
- Promoter Regions, Genetic
- Quinuclidines/pharmacology
- Quinuclidines/therapeutic use
- Rats
- Rats, Sprague-Dawley
- Receptor, Fibroblast Growth Factor, Type 1/biosynthesis
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptors, Nicotinic/physiology
- Reflex, Startle/drug effects
- Schizophrenia/drug therapy
- Schizophrenia/metabolism
- Schizophrenic Psychology
- Social Behavior
- Tyrosine 3-Monooxygenase/genetics
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- T A Hauser
- Preclinical Research, Targacept, Inc, Winston-Salem, NC 27101, USA.
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14
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Sharma G, Vijayaraghavan S. Nicotinic receptors containing the alpha7 subunit: a model for rational drug design. Curr Med Chem 2009; 15:2921-32. [PMID: 19075644 DOI: 10.2174/092986708786848703] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neuronal nicotinic receptor has gained considerable recognition as a target, not just for combating drug addiction but also for treating a number of illnesses ranging from neurodegenerative diseases to psychotic disorders like schizophrenia. This recognition has led to a burgeoning field examining the receptor at all levels. A class of nicotinic receptors that contains the alpha7 gene product, apparently as a homomer, illustrates this multidisciplinary approach. Here, we review recent progress in our understanding of this class of receptors based on data from molecular, structural, physiological and patho-physiological studies. These studies have set the stage for rational drug design to combat disorders of the central nervous system. The studies also exemplify the cautious approach needed in developing CNS therapies and the importance of physiology in tempering drug design.
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Affiliation(s)
- G Sharma
- Department of Physiology and Biophysics and Neuroscience Program, University of Colorado, Denver, School of Medicine, Aurora Colorado, USA
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15
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Patel AB, Malpass JR. Potential Nicotinic Acetylcholine Receptor Ligands from 2,4-Methanoproline Derivatives. J Med Chem 2008; 51:7005-9. [DOI: 10.1021/jm800537a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anup B. Patel
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - John R. Malpass
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, United Kingdom
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16
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Springer SK, Woodin KS, Berry V, Boezio AA, Cao L, Clarkin K, Harmange JC, Hierl M, Knop J, Malmberg AB, McDermott JS, Nguyen HQ, Waldon D, Albrecht BK, McDonough SI. Synthesis and activity of substituted carbamates as potentiators of the alpha4beta2 nicotinic acetylcholine receptor. Bioorg Med Chem Lett 2008; 18:5643-7. [PMID: 18805006 DOI: 10.1016/j.bmcl.2008.08.092] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 02/06/2023]
Abstract
The synthesis and structure-activity relationship of a series of carbamate potentiators of alpha4beta2 nAChR is reported herein. These compounds were highly selective for alpha4beta2 over other nAChR subtypes. In addition, compounds increased the response of alpha4beta2 nAChRs to acetylcholine, as measured with patch-clamp electrophysiology.
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Affiliation(s)
- Stephanie K Springer
- Department of Medicinal Chemistry, Amgen Inc., 1 Kendall Square, Building 1000, Cambridge, MA, USA.
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17
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Albrecht BK, Berry V, Boezio AA, Cao L, Clarkin K, Guo W, Harmange JC, Hierl M, Huang L, Janosky B, Knop J, Malmberg A, McDermott JS, Nguyen HQ, Springer SK, Waldon D, Woodin K, McDonough SI. Discovery and optimization of substituted piperidines as potent, selective, CNS-penetrant alpha4beta2 nicotinic acetylcholine receptor potentiators. Bioorg Med Chem Lett 2008; 18:5209-12. [PMID: 18789861 DOI: 10.1016/j.bmcl.2008.08.080] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 08/20/2008] [Accepted: 08/22/2008] [Indexed: 02/06/2023]
Abstract
The discovery of a series of small molecule alpha4beta2 nAChR potentiators is reported. The structure-activity relationship leads to potent compounds selective against nAChRs including alpha3beta2 and alpha3beta4 and optimized for CNS penetrance. Compounds increased currents through recombinant alpha4beta2 nAChRs, yet did not compete for binding with the orthosteric ligand cytisine. High potency and efficacy on the rat channel combined with good PK properties will allow testing of the alpha4beta2 potentiator mechanism in animal models of disease.
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Affiliation(s)
- Brian K Albrecht
- Department of Medicinal Chemistry, Amgen Inc., One Kendall Square, Building 1000, Cambridge, MA, USA.
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18
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Charton Y, Guillonneau C, Lockhart B, Lestage P, Goldstein S. Preparation and affinity profile of novel nicotinic ligands. Bioorg Med Chem Lett 2008; 18:2188-93. [DOI: 10.1016/j.bmcl.2007.12.075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
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19
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Nizri E, Irony-Tur-Sinai M, Lavon I, Meshulam H, Amitai G, Brenner T. IBU-octyl-cytisine, a novel bifunctional compound eliciting anti-inflammatory and cholinergic activity, ameliorates CNS inflammation by inhibition of T-cell activity. Int Immunopharmacol 2007; 7:1129-39. [PMID: 17630191 DOI: 10.1016/j.intimp.2007.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/22/2007] [Accepted: 03/26/2007] [Indexed: 11/25/2022]
Abstract
Experimental autoimmune encephalomyelitis (EAE) is a central nervous system (CNS) inflammatory model in which MOG-specific T-cells initiate an autoimmune attack leading to demyelinization and consequently, neurological damage and morbidity. As EAE pathogenesis results from the involvement of immune cells, CNS resident-cells and inflammatory mediators, our treatment strategy was to use a bifunctional compound with dual anti-inflammatory properties: a non-steroidal anti-inflammatory moiety and a nicotinic agonist moiety, intended to interact with the alpha7 nicotinic receptor present on immune cells. We used IBU-Octyl-Cytisine, with an ibuprofen (IBU) moiety and Cytisine, as the nicotinic agonist. The two moieties are attached by an eight carbon (octyl) spacer. Treatment of EAE with IBU-Octyl-Cytisine (2.5 mg/kg/day, i.p.) reduced significantly (by 70%) disease severity and inflammatory infiltrates in the spinal cord. An equivalent dose of IBU was ineffective, whereas Cytisine was significantly toxic. Treatment with IBU-Octyl-Cytisine inhibited the T-cell response toward the encephalitogenic epitope of myelin oligodendrocyte glycoprotein (MOG). In addition, expression of CCR5 by CD4(+)T-cells was lower, indicating a reduced migratory capacity following treatment. IBU-Octyl-Cytisine reduced Th(1) but not Th(2) cytokine production. This reduction was accompanied by a drop in the level of T-bet mRNA, a transcription factor pivotal to Th(1) lineage differentiation. Thus, IBU-Octyl-Cytisine is an effective treatment for EAE, influencing T-cell responses in several stages of disease pathogenesis. This bifunctional compound was more efficient than IBU or Cytisine separately, as well as than both moieties unconjugated. Thus, it seems that this strategy may be applicable in wider context.
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Affiliation(s)
- Eran Nizri
- Laboratory of Neuroimmunology, Department of Neurology and the Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, Israel
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20
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Walker DP, Wishka DG, Piotrowski DW, Jia S, Reitz SC, Yates KM, Myers JK, Vetman TN, Margolis BJ, Jacobsen EJ, Acker BA, Groppi VE, Wolfe ML, Thornburgh BA, Tinholt PM, Cortes-Burgos LA, Walters RR, Hester MR, Seest EP, Dolak LA, Han F, Olson BA, Fitzgerald L, Staton BA, Raub TJ, Hajos M, Hoffmann WE, Li KS, Higdon NR, Wall TM, Hurst RS, Wong EHF, Rogers BN. Design, synthesis, structure–activity relationship, and in vivo activity of azabicyclic aryl amides as α7 nicotinic acetylcholine receptor agonists. Bioorg Med Chem 2006; 14:8219-48. [PMID: 17011782 DOI: 10.1016/j.bmc.2006.09.019] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2006] [Revised: 09/11/2006] [Accepted: 09/11/2006] [Indexed: 11/28/2022]
Abstract
A novel set of azabicyclic aryl amides have been identified as potent and selective agonists of the alpha7 nAChR. A two-pronged approach was taken to improve the potential hERG liability of previously disclosed alpha7 nAChR agonist, PNU-282,987, while maintaining the compound's other desirable pharmacological properties. The first approach involved further exploration of the aryl carboxylic acid fragment of PNU-282,987, while the second approach focused on modification of the azabicyclic amine portion of PNU-282,987. The best compounds from each series are characterized by rapid brain penetration, good oral bioavailability in rat, and demonstrate in vivo efficacy in a rat P50 auditory sensory gating assay. At least one analog from each series (1h, 1o, 2a, 9a, and 18a) shows an improved hERG safety profile over PNU-282,987.
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Affiliation(s)
- Daniel P Walker
- Neuroscience Research, Pfizer Global Research and Development, Eastern Point Rd., Groton, CT 06340, USA
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21
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Wang Y, Sherwood JL, Lodge D. The alpha4beta2 nicotinic acetylcholine receptor agonist TC-2559 impairs long-term potentiation in the dentate gyrus in vivo. Neurosci Lett 2006; 406:183-8. [PMID: 16935422 DOI: 10.1016/j.neulet.2006.06.075] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 06/26/2006] [Accepted: 06/29/2006] [Indexed: 11/27/2022]
Abstract
Nicotinic acetylcholine receptors (nAChR) are widely expressed throughout the nervous system, are involved in some fast excitatory neurotransmission, and play an important role in modulating the release of several neurotransmitters, including the major excitatory and inhibitory neurotransmitters, glutamate and GABA. We used a recently characterised alpha4beta2 nAChR subunit selective partial agonist, TC-2559, to study the effect of alpha4beta2 nAChR activation on synaptic plasticity in the medio-dorsal perforant pathway input to the dentate gyrus, in the intact nervous system in vivo. We show for the first time, that the selective activation of alpha4beta2 containing nAChR can reduce the level of long-term potentiation (LTP) induced by high frequency stimulation, an effect that was reversed by the selective antagonist, dihydro-beta-erythroidine (DbetaHE). This modulator role of nAChRs is in contrast to previous findings that used broad spectrum agonists, highlighting the complex actions of nicotine.
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Affiliation(s)
- Yun Wang
- Lilly Research Centre, Eli Lilly & Co Ltd, Erl Wood Manor, Windlesham, Surrey, UK
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22
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Broad LM, Zwart R, Pearson KH, Lee M, Wallace L, McPhie GI, Emkey R, Hollinshead SP, Dell CP, Baker SR, Sher E. Identification and pharmacological profile of a new class of selective nicotinic acetylcholine receptor potentiators. J Pharmacol Exp Ther 2006; 318:1108-17. [PMID: 16738207 DOI: 10.1124/jpet.106.104505] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Here we report the discovery, by high-throughput screening, of three novel (2-amino-5-keto)thiazole compounds that act as selective potentiators of nicotinic acetylcholine receptors. Compound selectivity was assessed at seven human nicotinic acetylcholine receptors (alpha1beta1gammadelta, alpha2beta4, alpha3beta2, alpha3beta4, alpha4beta2, alpha4beta4, and alpha7) expressed in mammalian cells or Xenopus oocytes. At alpha2beta4, alpha4beta2, alpha4beta4, and alpha7, but not alpha1beta1gammadelta, alpha3beta2, or alpha3beta4, submaximal responses to nicotinic agonists were potentiated in a concentration-dependent manner by all compounds. At similar concentrations, no potentiation of 5-hydroxytryptamine, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, GABA(A), and N-methyl-d-aspartate receptors or voltage-gated Na(+) and Ca(2+) channels was observed. Furthermore, these compounds did not inhibit acetylcholine esterase. Further profiling revealed that these compounds enhanced the potency and maximal efficacy of a range of nicotinic agonists at alpha4beta2 nicotinic acetylcholine receptors, a profile typical of allosteric potentiators. At concentrations required for potentiation, the compounds did not displace [(3)H]epibatidine from the agonist-binding site, and potentiation was observed at all agonist concentrations, suggesting a noncompetitive mechanism of action. Blockade of common second messenger systems did not affect potentiation. At concentrations higher then required for potentiation the compounds also displayed intrinsic agonist activity, which was blocked by competitive and noncompetitive nicotinic acetylcholine receptor (nAChR) antagonists. These novel selective nicotinic receptor potentiators should help in clarifying the potential therapeutic utility of selective nAChR modulation for the treatment of central nervous system disorders.
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Affiliation(s)
- Lisa M Broad
- Eli Lilly and Company Ltd., Lilly Research Centre, Windlesham, Surrey GU20 6PH, UK
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23
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Wang Y, Sherwood JL, Miles CP, Whiffin G, Lodge D. TC-2559 excites dopaminergic neurones in the ventral tegmental area by stimulating alpha4beta2-like nicotinic acetylcholine receptors in anaesthetised rats. Br J Pharmacol 2006; 147:379-90. [PMID: 16402043 PMCID: PMC1616994 DOI: 10.1038/sj.bjp.0706621] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 10/14/2005] [Accepted: 11/15/2005] [Indexed: 11/09/2022] Open
Abstract
1. The in vivo effects of a selective partial agonist for neuronal nicotinic acetylcholine receptor (nAChRs) alpha4beta2 subtype, TC-2559, characterised recently in in vitro preparations, have been profiled. The brain bioavailability of TC-2559 and its effects on the spontaneous firing and bursting properties of the dopaminergic (DAergic) neurones recorded extracellularly in the ventral tegmental area (VTA) were studied following systemic administration in anaesthetised rats. 2. Cumulative doses of TC-2559 (0.021-1.36 mg kg(-1), i.v.) increased both the firing and bursting activities of VTA DA neurones. The effect of bolus doses of TC-2559 of 0.66 or 1.32 mg kg(-1), i.v., was approximately equivalent to that of 0.0665 mg kg(-1), i.v. nicotine. 3. The excitation evoked by both nicotine and TC-2559 was fully reversed by DHbetaE (0.39-0.77 mg kg(-1), i.v.), an alpha4beta2-subtype-preferring nicotinic antagonist, and application of nicotine after DHbetaE failed to evoke any excitation. MLA (0.23 mg kg(-1), i.v.), an alpha7 selective antagonist, failed to alter TC-2559-evoked excitation and bursting activities, and a novel alpha7 agonist (PSAB-OFP; 0.23 mg kg(-1), i.v.) was also without effect. 4. The present results indicated that TC-2559 fully mimics nicotine by increasing both the excitability and bursting behaviour of VTA DA neurones, effects that are predominantly due to activation of alpha4beta2-like nAChRs. 5. TC-2559 has been demonstrated to be a useful in vivo pharmacological tool for studying the alpha4beta2 subtype of nicotinic receptor.
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Affiliation(s)
- Yun Wang
- Lilly Research Centre, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey GU20 6PH.
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24
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Exley R, Iturriaga-Vásquez P, Lukas RJ, Sher E, Cassels BK, Bermudez I. Evaluation of benzyltetrahydroisoquinolines as ligands for neuronal nicotinic acetylcholine receptors. Br J Pharmacol 2005; 146:15-24. [PMID: 15980871 PMCID: PMC1576253 DOI: 10.1038/sj.bjp.0706307] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Effects of derivatives of coclaurine (C), which mimic the 'eastern' or the nonquaternary halves of the alkaloids tetrandrine or d-tubocurarine, respectively, both of which are inhibitors of nicotinic acetylcholine receptors (nACh), were examined on recombinant, human alpha7, alpha4beta2 and alpha4beta4 nACh receptors expressed in Xenopus oocytes and clonal cell lines using two-electrode voltage clamping and radioligand binding techniques. In this limited series, Cs have higher affinity and are most potent at alpha4 subunit-containing-nACh receptors and least potent at homomeric alpha7 receptors, and this trend is very marked for the N-unsubstituted C and its O,O'-bisbenzyl derivative. 7-O-Benzyl-N-methylcoclaurine (BBCM) and its 12-O-methyl derivative showed the highest affinities and potencies at all three receptor subtypes, and this suggests that lipophilicity at C7 and/or C12 increases potency. Laudanosine and armepavine (A) were noncompetitive and voltage-dependent inhibitors of alpha7, alpha4beta2 or alpha4beta4 receptors, but the bulkier C7-benzylated 7BNMC (7-O-benzyl-N-methylcoclaurine) and 7B12MNMC (7-O-benzyl-N,12-O-dimethyl coclaurine) were voltage-independent, noncompetitive inhibitors of nACh receptors. Voltage-dependence was also lost on going from A to its N-ethyl analogue. These studies suggest that C derivatives may be useful tools for studies characterising the antagonist and ion channel sites on human alpha7, alpha4beta2 or alpha4beta4 nACh receptors and for revealing structure-function relationships for nACh receptor antagonists.
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Affiliation(s)
- Richard Exley
- School of Biological and Molecular Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP
| | - Patricio Iturriaga-Vásquez
- Millennium Institute for Advanced Studies in Cell Biology and Biotechnology and Department of Chemistry, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Ronald J Lukas
- Division of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, U.S.A
| | - Emanuele Sher
- Eli Lilly and Co. Lilly Research Centre, Erl Wood Manor, Windlesham, Surrey
| | - Bruce K Cassels
- Millennium Institute for Advanced Studies in Cell Biology and Biotechnology and Department of Chemistry, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Isabel Bermudez
- School of Biological and Molecular Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP
- Author for correspondence:
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25
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Baker SR, Boot J, Brunavs M, Dobson D, Green R, Hayhurst L, Keenan M, Wallace L. High affinity ligands for the α7 nicotinic receptor that show no cross-reactivity with the 5-HT3 receptor. Bioorg Med Chem Lett 2005; 15:4727-30. [PMID: 16165358 DOI: 10.1016/j.bmcl.2005.07.070] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Revised: 07/14/2005] [Accepted: 07/26/2005] [Indexed: 11/22/2022]
Abstract
Potent and selective ligands of the alpha7 nicotinic acetylcholine receptor are required to understand the pharmacological effect of alpha7 activation. A common cross-reactivity occurs with serotonergic 5-HT3 receptors with which alpha7 receptors have a high sequence homology. We demonstrate that certain quinuclidine 3-biaryl carboxamides are high affinity alpha7 ligands with an excellent binding selectivity over 5-HT3 receptors.
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Affiliation(s)
- S Richard Baker
- Eli Lilly and Company Ltd., Lilly Research Centre, Erl Wood Manor, Windlesham, Surrey, GU20 6PH, UK
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26
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Ma Z, Strecker RE, McKenna JT, Thakkar MM, McCarley RW, Tao R. Effects on serotonin of (-)nicotine and dimethylphenylpiperazinium in the dorsal raphe and nucleus accumbens of freely behaving rats. Neuroscience 2005; 135:949-58. [PMID: 16154286 DOI: 10.1016/j.neuroscience.2005.06.074] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 06/14/2005] [Accepted: 06/17/2005] [Indexed: 10/25/2022]
Abstract
The aim of this study was to investigate the neurochemical mechanism underlying the effect of nicotine and dimethylphenylpiperazinium (DMPP) on 5-hydroxytryptamine (5-HT) release in the dorsal raphe nucleus and nucleus accumbens of freely behaving rats. For comparison, lobeline, cytisine and RJR-2403 were also investigated. It was found that all drugs, when infused locally, evoked an increase of 5-HT in the dorsal raphe nucleus. However, the magnitudes of the 5-HT increase were comparatively different between the drugs in the ranking of their potency: DMPP>RJR 2403>>nicotine>lobeline>cytisine. Both methyllycaconitine, a nicotinic acetylcholine receptor (nAChR) antagonist and methyllycaconitine, a selective alpha7-containing nAChR antagonist blocked the effects of nicotine and DMPP, suggesting that alpha7 subunit mediated the increases in 5-HT. However, DMPP was reported to increase 5-HT using non-nAChR mechanism [Lendvai B, Sershen H, Lajtha A, Santha E, Baranyi M, Vizi ES (1996) Differential mechanisms involved in the effect of nicotinic agonists DMPP and lobeline to release [3H]5-HT from rat hippocampal slices. Neuropharmacology 35:1769-1777]. To test if 5-HT carriers were involved, a selective 5-HT reuptake inhibitor citalopram (1 microM) was infused into the dorsal raphe nucleus before administration of nicotine or DMPP. As a result, citalopram significantly blocked the effect of DMPP, whereas it had no influence on nicotine. Finally, the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) was used to test whether the increases in 5-HT were depolarization-dependent. Administration of 8-OH-DPAT (0.1 mg/kg, s.c.) produced significant decreases in 5-HT in the animals treated with nicotine. In contrast, the effect of DMPP was not altered by 8-OH-DPAT, suggesting that the increases in 5-HT were independent of cell membrane depolarization. In conclusion, there are different mechanisms involved in nicotine- and DMPP-evoked increases in 5-HT. This is consistent with prior work suggesting DMPP may primarily act on 5-HT carriers.
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Affiliation(s)
- Z Ma
- Department of Biomedical Science, Charles E. Schmidt College of Science, Florida Atlantic University, 777 Glades Road, P.O. Box 3091, Boca Raton, FL 33431-0991, USA
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27
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Bunnelle WH, Decker MW. Neuronal nicotinic acetylcholine receptor ligands as potential analgesics. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.13.7.1003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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29
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Hogg RC, Bertrand D. Neuronal nicotinic receptors and epilepsy, from genes to possible therapeutic compounds. Bioorg Med Chem Lett 2004; 14:1859-61. [PMID: 15050616 DOI: 10.1016/j.bmcl.2003.10.075] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2003] [Indexed: 11/18/2022]
Affiliation(s)
- Ronald C Hogg
- Department of Physiology, Medical Faculty, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland
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30
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Papke RL, Porter Papke JK, Rose GM. Activity of α7-selective agonists at nicotinic and serotonin 5HT3 receptors expressed in Xenopus oocytes. Bioorg Med Chem Lett 2004; 14:1849-53. [PMID: 15050614 DOI: 10.1016/j.bmcl.2003.09.104] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2003] [Accepted: 09/17/2003] [Indexed: 11/20/2022]
Abstract
Nicotinic receptors containing alpha7 subunits are widely distributed in the central nervous system and are thought to be involved in a number of functions. However, it has been difficult to study alpha7-containing receptors in vivo because of a paucity of selective agonists. A new spirooxazolidinone compound, AR-R17779, was recently described as potent agonist at alpha7 receptors, but electrophysiological studies at other types of nicotinic receptors have not been carried out. We characterized the activity of AR-R17779 at alpha7, alpha4beta2, alpha3beta4, alpha3beta2, alpha3beta2alpha5 receptors expressed in Xenopus oocytes. In addition, since there is significant homology between nicotinic alpha7 and serotonin 5HT(3) receptors, the activity of AR-R17779 at expressed 5HT(3a) receptors was also examined. Finally, actions of tropisetron and ondansetron, two 5HT(3) antagonists, were explored. AR-R17779 was found to activate alpha7 receptors, but had no activity at other types of nicotinic receptors, and also had no activity at 5HT(3a) receptors. Tropisetron activated, while ondansetron acted as an antagonist, at alpha7 nicotinic receptors. The two 5HT(3) antagonists also acted as antagonists at alpha4beta2 and alpha3beta4 nicotinic receptors. Thus, AR-R17779 was confirmed to be a selective nicotinic alpha7 receptor agonist and to be without activity at 5HT(3) receptors. In contrast, the actions of tropisetron and ondansetron on nicotinic receptors were complex.
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MESH Headings
- Animals
- Bridged-Ring Compounds/metabolism
- Bridged-Ring Compounds/pharmacology
- Dose-Response Relationship, Drug
- Female
- Indoles/metabolism
- Indoles/pharmacology
- Nicotinic Agonists/metabolism
- Nicotinic Agonists/pharmacology
- Ondansetron/metabolism
- Ondansetron/pharmacology
- Oocytes/drug effects
- Oocytes/physiology
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Receptors, Serotonin, 5-HT3/drug effects
- Receptors, Serotonin, 5-HT3/genetics
- Receptors, Serotonin, 5-HT3/metabolism
- Serotonin Antagonists/metabolism
- Serotonin Antagonists/pharmacology
- Spiro Compounds/metabolism
- Spiro Compounds/pharmacology
- Structure-Activity Relationship
- Tropisetron
- Xenopus laevis
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- R L Papke
- Department of Pharmacology, University of Florida, PO Box 100267, 1600 SW Archer Rd, Gainesville, FL 32610, USA.
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31
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Bremner JB, Godfrey CA, Jensen AA, Smith RJ. Synthesis and nicotinic receptor activity of a hydroxylated tropane. Bioorg Med Chem Lett 2004; 14:271-3. [PMID: 14684341 DOI: 10.1016/j.bmcl.2003.09.081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
(+/-)-3alpha-hydroxy homoepibatidine 4 has been synthesized from the alkaloid scopolamine 5 and its properties as a nicotinic agonist assessed. While still binding strongly, the compound showed reduced agonist potency for the alpha(4)beta(2) nAChR compared with the parent compound epibatidine 1. Compound 4 also displayed generally similar binding and selectivity profiles at alpha(4)beta(2), alpha(2)beta(4), alpha(3)beta(4), and alpha(4)beta(4) nAChR subtypes to those for nicotine.
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Affiliation(s)
- John B Bremner
- Department of Chemistry and Institute for Biomolecular Science, University of Wollongong, Wollongong, NSW 2522, Australia.
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32
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Chen Y, Sharples TJW, Phillips KG, Benedetti G, Broad LM, Zwart R, Sher E. The nicotinic alpha 4 beta 2 receptor selective agonist, TC-2559, increases dopamine neuronal activity in the ventral tegmental area of rat midbrain slices. Neuropharmacology 2003; 45:334-44. [PMID: 12871651 DOI: 10.1016/s0028-3908(03)00189-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The ability of alpha4beta2 nicotinic acetylcholine receptors to modulate dopaminergic (DA) cell activity in the ventral tegmental area (VTA) in rat midbrain slices was assessed using a selective alpha4beta2 receptor agonist, TC-2559 ((E)-N-methyl-4-[3-(5-ethoxypyridin)y1]-3-buten-1-amine). The selectivity of TC-2559 was characterized across 6 recombinant human nicotinic receptors (alpha4beta2, alpha2beta4, alpha4beta4, alpha3beta4, alpha3beta2 and alpha7) stably expressed in mammalian cell lines. Using a fluorescent imaging plate reader and fluo-3 to monitor changes in intracellular calcium, TC-2559 was found to be at least 69 fold more potent on alpha4beta2 than on other heteromeric subtypes, with an efficacy of 33%. No activity on the homomeric alpha7 subtype was detected. TC-2559 also showed selectivity for alpha4beta2 over the alpha4beta4 and alpha7 subtypes expressed in Xenopus oocytes. When bath applied to VTA slices, TC-2559 increased the firing of DA cells in a dose-dependent manner, in the same concentration range that activates alpha4beta2 receptors in recombinant cell lines or oocytes. The effect of TC-2559 was blocked by 2 microM dihydro-beta-erythroidine (an alpha4beta2-preferring antagonist), but not by 10 nM methyllycaconitine (an alpha7 antagonist). Glutamate receptor antagonists (6-cyano-7-nitroquinoxaline-2,3-dione and D(-)-2-amino-5-phosphonopentanoic acid) did not reduce TC-2559-induced responses, suggesting that the increase in DA cell firing induced by TC-2559 is caused by direct postsynaptic depolarisation via the activation of alpha4beta2 receptors and not by enhancement of glutamate release.
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Affiliation(s)
- Ying Chen
- Lilly Research Centre, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Surrey GU20 6PH, Windlesham, UK.
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