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Mamczarz J, Lane M, Merchenthaler I. Letrozole delays acquisition of water maze task in female BALB/c mice: Possible involvement of anxiety. Horm Behav 2024; 162:105524. [PMID: 38513526 DOI: 10.1016/j.yhbeh.2024.105524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 02/25/2024] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Letrozole, an aromatase inhibitor preventing estrogen synthesis from testosterone, is used as an adjuvant therapy in estrogen receptor-positive breast cancer patients. However, like other aromatase inhibitors, it induces many side effects, including impaired cognition. Despite its negative effect in humans, results from animal models are inconsistent and suggest that letrozole can either impair or improve cognition. Here, we studied the effects of chronic letrozole treatment on cognitive behavior of adult female BALB/c mice, a relevant animal model for breast cancer studies, to develop an appropriate animal model aimed at testing therapies to mitigate side effects of letrozole. In Morris water maze, letrozole 0.1 mg/kg impaired reference learning and memory. Interestingly, most of the letrozole 0.1 mg/kg-treated mice were able to learn the new platform position in reversal training and performed similar to control mice in a reversal probe test. Results of the reversal test suggest that letrozole did not completely disrupt spatial navigation, but rather delayed acquisition of spatial information. The delay might be related to increased anxiety as suggested by increased thigmotactic behavior during the reference memory training. The learning impairment was water maze-specific since we did not observe impairment in other spatial tasks such as in Y-maze or object location test. In contrast, the dose of 0.3 mg/kg did not have effect on water maze learning and facilitated locomotor habituation and recognition in novel object recognition test. The current study shows that letrozole dose-dependently modulates behavioral response and that its effects are task-dependent.
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Affiliation(s)
- Jacek Mamczarz
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America.
| | - Malcolm Lane
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Istvan Merchenthaler
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
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Francotte P, Bay Y, Goffin E, Colson T, Lesenfants C, Dorosz J, Laulumaa S, Fraikin P, de Tullio P, Beaufour C, Botez I, Pickering DS, Frydenvang K, Danober L, Kristensen AS, Kastrup JS, Pirotte B. Exploring thienothiadiazine dioxides as isosteric analogues of benzo- and pyridothiadiazine dioxides in the search of new AMPA and kainate receptor positive allosteric modulators. Eur J Med Chem 2024; 264:116036. [PMID: 38101041 DOI: 10.1016/j.ejmech.2023.116036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
The synthesis and biological evaluation on AMPA and kainate receptors of new examples of 3,4-dihydro-2H-1,2,4-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxides is described. The introduction of a cyclopropyl chain instead of an ethyl chain at the 4-position of the thiadiazine ring was found to dramatically improve the potentiator activity on AMPA receptors, with compound 32 (BPAM395) expressing in vitro activity on AMPARs (EC2x = 0.24 μM) close to that of the reference 4-cyclopropyl-substituted benzothiadiazine dioxide 10 (BPAM344). Interestingly, the 4-allyl-substituted thienothiadiazine dioxide 27 (BPAM307) emerged as the most promising compound on kainate receptors being a more effective potentiator than the 4-cyclopropyl-substituted thienothiadiazine dioxide 32 and supporting the view that the 4-allyl substitution of the thiadiazine ring could be more favorable than the 4-cyclopropyl substitution to induce marked activity on kainate receptors versus AMPA receptors. The thieno-analogue 36 (BPAM279) of the clinically tested S18986 (11) was selected for in vivo evaluation in mice as a cognitive enhancer due to a safer profile than 32 after massive per os drug administration. Compound 36 was found to increase the cognition performance in mice at low doses (1 mg/kg) per os suggesting that the compound was well absorbed after oral administration and able to reach the central nervous system. Finally, compound 32 was selected for co-crystallization with the GluA2-LBD (L504Y,N775S) and glutamate to examine the binding mode of thienothiadiazine dioxides within the allosteric binding site of the AMPA receptor. At the allosteric site, this compound established similar interactions as the previously reported BTD-type AMPA receptor modulators.
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Affiliation(s)
- Pierre Francotte
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Yasmin Bay
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark
| | - Eric Goffin
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Thomas Colson
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Cindy Lesenfants
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Jerzy Dorosz
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark
| | - Saara Laulumaa
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark
| | - Pierre Fraikin
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Pascal de Tullio
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Caroline Beaufour
- Institut de Recherches et Développement Servier Paris-Saclay, 22 route 128, 91190, Gif-sur-Yvette, France
| | - Iuliana Botez
- Institut de Recherches et Développement Servier Paris-Saclay, 22 route 128, 91190, Gif-sur-Yvette, France
| | - Darryl S Pickering
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark
| | - Karla Frydenvang
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark
| | - Laurence Danober
- Institut de Recherches et Développement Servier Paris-Saclay, 22 route 128, 91190, Gif-sur-Yvette, France
| | - Anders Skov Kristensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark.
| | - Jette Sandholm Kastrup
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Copenhagen, Denmark.
| | - Bernard Pirotte
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium.
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Goffin E, Fraikin P, Abboud D, de Tullio P, Beaufour C, Botez I, Hanson J, Danober L, Francotte P, Pirotte B. New insights in the development of positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors belonging to 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides: Introduction of (mono/difluoro)methyl groups at the 2-position of the thiadiazine ring. Eur J Med Chem 2023; 250:115221. [PMID: 36863228 DOI: 10.1016/j.ejmech.2023.115221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 02/26/2023]
Abstract
Positive allosteric modulators of the AMPA receptors (AMPAR PAMs) have been proposed as new drugs for the management of various neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, attention deficit hyperactivity disorder, depression, and schizophrenia. The present study explored new AMPAR PAMs belonging to 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides (BTDs) characterized by the presence of a short alkyl substituent at the 2-position of the heterocycle and by the presence or absence of a methyl group at the 3-position. The introduction of a monofluoromethyl or a difluoromethyl side chain at the 2-position instead of the methyl group was examined. 7-Chloro-4-cyclopropyl-2-fluoromethyl-3,4-dihydro-4H-1,2,4-benzothiadiazine 1,1-dioxide (15e) emerged as the most promising compound associating high in vitro potency on AMPA receptors, a favorable safety profile in vivo and a marked efficacy as a cognitive enhancer after oral administration in mice. Stability studies in aqueous medium suggested that 15e could be considered, at least in part, as a precursor of the corresponding 2-hydroxymethyl-substituted analogue and the known AMPAR modulator 7-chloro-4-cyclopropyl-3,4-dihydro-4H-1,2,4-benzothiadiazine 1,1-dioxide (3) devoid of an alkyl group at the 2-position.
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Affiliation(s)
- Eric Goffin
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Pierre Fraikin
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Dayana Abboud
- Laboratory of Molecular Pharmacology, GIGA-Molecular Biology of Diseases, University of Liège, Avenue Hippocrate 1/11 (B34), B-4000, Liège, Belgium
| | - Pascal de Tullio
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Caroline Beaufour
- Institut de Recherches Servier, 125 Chemin de Ronde, F-78290, Croissy-sur-Seine, France
| | - Iuliana Botez
- Institut de Recherches Servier, 125 Chemin de Ronde, F-78290, Croissy-sur-Seine, France
| | - Julien Hanson
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium; Laboratory of Molecular Pharmacology, GIGA-Molecular Biology of Diseases, University of Liège, Avenue Hippocrate 1/11 (B34), B-4000, Liège, Belgium
| | - Laurence Danober
- Institut de Recherches Servier, 125 Chemin de Ronde, F-78290, Croissy-sur-Seine, France
| | - Pierre Francotte
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium
| | - Bernard Pirotte
- Center for Interdisciplinary Research on Medicines (CIRM) - Laboratory of Medicinal Chemistry, University of Liège, Avenue Hippocrate 15 (B36), B-4000, Liège, Belgium.
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Jakkamsetti V, Scudder W, Kathote G, Ma Q, Angulo G, Dobariya A, Rosenberg RN, Beutler B, Pascual JM. Quantification of early learning and movement sub-structure predictive of motor performance. Sci Rep 2021; 11:14405. [PMID: 34257385 PMCID: PMC8277799 DOI: 10.1038/s41598-021-93944-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 07/01/2021] [Indexed: 11/09/2022] Open
Abstract
Time-to-fall off an accelerating rotating rod (rotarod) is widely utilized to evaluate rodent motor performance. We reasoned that this simple outcome could be refined with additional measures explicit in the task (however inconspicuously) to examine what we call movement sub-structure. Our goal was to characterize normal variation or motor impairment more robustly than by using time-to-fall. We also hypothesized that measures (or features) early in the sub-structure could anticipate the learning expected of a mouse undergoing serial trials. Using normal untreated and baclofen-treated movement-impaired mice, we defined these features and automated their analysis using paw video-tracking in three consecutive trials, including paw location, speed, acceleration, variance and approximate entropy. Spectral arc length yielded speed and acceleration uniformity. We found that, in normal mice, paw movement smoothness inversely correlated with rotarod time-to-fall for the three trials. Greater approximate entropy in vertical movements, and opposite changes in horizontal movements, correlated with greater first-trial time-to-fall. First-trial horizontal approximate entropy in the first few seconds predicted subsequent time-to-fall. This allowed for the separation, after only one rotarod trial, of different-weight, untreated mouse groups, and for the detection of mice otherwise unimpaired after baclofen, which displayed a time-to-fall similar to control. A machine-learning support vector machine classifier corroborated these findings. In conclusion, time-to-fall off a rotarod correlated well with several measures, including some obtained during the first few seconds of a trial, and some responsive to learning over the first two trials, allowing for predictions or preemptive experimental manipulations before learning completion.
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Affiliation(s)
- Vikram Jakkamsetti
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA.
| | - William Scudder
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Gauri Kathote
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Qian Ma
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Gustavo Angulo
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Aksharkumar Dobariya
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Roger N Rosenberg
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bruce Beutler
- Center for the Genetics of Host Defense, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Juan M Pascual
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Mail Code 8813, Dallas, TX, 75390-8813, USA.
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Eugene McDermott Center for Human Growth and Development/Center for Human Genetics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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5
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Vo BN, Abney KK, Anderson A, Marron Fernandez de Velasco E, Benneyworth MA, Daniels JS, Morrison RD, Hopkins CR, Weaver CD, Wickman K. VU0810464, a non-urea G protein-gated inwardly rectifying K + (K ir 3/GIRK) channel activator, exhibits enhanced selectivity for neuronal K ir 3 channels and reduces stress-induced hyperthermia in mice. Br J Pharmacol 2019; 176:2238-2249. [PMID: 30924523 DOI: 10.1111/bph.14671] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/16/2019] [Accepted: 02/20/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE G protein-gated inwardly rectifying K+ (Kir 3) channels moderate the activity of excitable cells and have been implicated in neurological disorders and cardiac arrhythmias. Most neuronal Kir 3 channels consist of Kir 3.1 and Kir 3.2 subtypes, while cardiac Kir 3 channels consist of Kir 3.1 and Kir 3.4 subtypes. Previously, we identified a family of urea-containing Kir 3 channel activators, but these molecules exhibit suboptimal pharmacokinetic properties and modest selectivity for Kir 3.1/3.2 relative to Kir 3.1/3.4 channels. Here, we characterize a non-urea activator, VU0810464, which displays nanomolar potency as a Kir 3.1/3.2 activator, improved selectivity for neuronal Kir 3 channels, and improved brain penetration. EXPERIMENTAL APPROACH We used whole-cell electrophysiology to measure the efficacy and potency of VU0810464 in neurons and the selectivity of VU0810464 for neuronal and cardiac Kir 3 channel subtypes. We tested VU0810464 in vivo in stress-induced hyperthermia and elevated plus maze paradigms. Parallel studies with ML297, the prototypical activator of Kir 3.1-containing Kir 3 channels, were performed to permit direct comparisons. KEY RESULTS VU0810464 and ML297 exhibited comparable efficacy and potency as neuronal Kir 3 channel activators, but VU0810464 was more selective for neuronal Kir 3 channels. VU0810464, like ML297, reduced stress-induced hyperthermia in a Kir 3-dependent manner in mice. ML297, but not VU0810464, decreased anxiety-related behaviour as assessed with the elevated plus maze test. CONCLUSION AND IMPLICATIONS VU0810464 represents a new class of Kir 3 channel activator with enhanced selectivity for Kir 3.1/3.2 channels. VU0810464 may be useful for examining Kir 3.1/3.2 channel contributions to complex behaviours and for probing the potential of Kir 3 channel-dependent manipulations to treat neurological disorders.
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Affiliation(s)
- Baovi N Vo
- Department of Pharmacology, University of Minnesota, Minneapolis, MN
| | - Kristopher K Abney
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN
| | - Allison Anderson
- Department of Pharmacology, University of Minnesota, Minneapolis, MN
| | | | | | | | - Ryan D Morrison
- Research and Development, Precera Bioscience, Inc., Franklin, TN
| | - Corey R Hopkins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE
| | | | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN
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Zarrabian S, Nasehi M, Farrahizadeh M, Zarrindast MR. The role of CA3 GABA B receptors on anxiolytic-like behaviors and avoidance memory deficit induced by D-AP5 with respect to Ca 2+ ions. Prog Neuropsychopharmacol Biol Psychiatry 2017; 79:515-524. [PMID: 28800869 DOI: 10.1016/j.pnpbp.2017.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 08/03/2017] [Accepted: 08/07/2017] [Indexed: 01/21/2023]
Abstract
Glutamatergic and GABAergic systems play key roles in the hippocampus and affect the pathogenesis of anxiety- and memory-related processes. Some investigations have assessed the role of balancing the function of these two systems in different areas of the central nervous system (CNS) as an approach to manage the related disorders. We investigated the anxiety and avoidance memory states using the test-retest protocol in the elevated plus maze to understand the role of GABAB receptors (GABABRs) in relation to the NMDA receptor blockade by D-AP5 (an NMDA receptor antagonist). Also, we examined the function of Ca2+ ions by blocking its entrance to the cell using SKF96365 (a Ca2+ channel blocker). The drugs were injected into the CA3 region before the test. Our data showed that D-AP5 induced anxiolytic-like behaviors and impaired the avoidance memory. Injection of baclofen (a GABABR agonist), but not phaclofen (a GABABR antagonist) induced anxiolytic-like behaviors. Neither baclofen nor phaclofen altered avoidance memory-related behaviors. When baclofen was injected before D-AP5, it potentiated the anxiolytic-like behaviors induced by D-AP5, but counteracted its effect on avoidance memory. Phaclofen pretreatment attenuated D-AP5-induced anxiolytic-like behaviors, but potentiated its effect on avoidance memory. The effect of baclofen application before D-AP5 on anxiety and phaclofen application before D-AP5 on avoidance memory at the heist doses were accompanied by a decrease in locomotion. The application of SKF96365 did not alter anxiety-like behaviors but induced avoidance memory impairment. SKF96365 application before the combination of baclofen and D-AP5 counteracted the effects produced by the combination of baclofen and D-AP5 on anxiety and memory states. Our findings showed that the CA3 GABABRs had a critical role in anxiolytic-like behaviors and avoidance memory deficit induced by D-AP5 and confirmed the role of Ca2+ ions in the observed results.
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Affiliation(s)
- Shahram Zarrabian
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Mohammad Nasehi
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran; Institute for Cognitive Science Studies (ICSS), Tehran, Iran.
| | - Maryam Farrahizadeh
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Mohammad-Reza Zarrindast
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran; Institute for Cognitive Science Studies (ICSS), Tehran, Iran; Department of Pharmacology School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran; School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran; Medical Genomics Research Center, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran.
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Slattery DA, Cryan JF. Modelling depression in animals: at the interface of reward and stress pathways. Psychopharmacology (Berl) 2017; 234:1451-1465. [PMID: 28224183 DOI: 10.1007/s00213-017-4552-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/27/2017] [Indexed: 12/13/2022]
Abstract
RATIONALE Despite substantial research efforts the aetiology of major depressive disorder (MDD) remains poorly understood, which is due in part to the heterogeneity of the disorder and the complexity of designing appropriate animal models. However, in the last few decades, a focus on the development of novel stress-based paradigms and a focus on using hedonic/anhedonic behaviour have led to renewed optimism in the use of animal models to assess aspects of MDD. OBJECTIVES Therefore, in this review article, dedicated to Athina Markou, we summarise the use of stress-based animal models for studying MDD in rodents and how reward-related readouts can be used to validate/assess the model and/or treatment. RESULTS We reveal the use and limitations of chronic stress paradigms, which we split into non-social (i.e. chronic mild stress), social (i.e. chronic social defeat) and drug-withdrawal paradigms for studying MDD and detail numerous reward-related readouts that are employed in preclinical research. Finally, we finish with a section regarding important factors to consider when using animal models. CONCLUSIONS One of the most consistent findings following chronic stress exposure in rodents is a disruption of the brain reward system, which can be easily assessed using sucrose, social interaction, food, drug of abuse or intracranial self-stimulation as a readout. Probing the underlying causes of such alterations is providing a greater understanding of the potential systems and processes that are disrupted in MDD.
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Affiliation(s)
- D A Slattery
- Laboratory of Translational Psychiatry, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Heinrich-Hoffmann-Str. 10, 60528, Frankfurt, Germany.
| | - J F Cryan
- APC Microbiome Institute, Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
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Kalinichev M, Girard F, Haddouk H, Rouillier M, Riguet E, Royer-Urios I, Mutel V, Lütjens R, Poli S. The drug candidate, ADX71441, is a novel, potent and selective positive allosteric modulator of the GABA B receptor with a potential for treatment of anxiety, pain and spasticity. Neuropharmacology 2016; 114:34-47. [PMID: 27889489 DOI: 10.1016/j.neuropharm.2016.11.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 11/13/2016] [Accepted: 11/21/2016] [Indexed: 11/17/2022]
Abstract
Positive allosteric modulation of the GABAB receptor is a promising alternative to direct activation of the receptor as a therapeutic approach for treatment of addiction, chronic pain, anxiety, epilepsy, autism, Fragile X syndrome, and psychosis. Here we describe in vitro and in vivo characterization of a novel, potent and selective GABAB positive allosteric modulator (PAM) N-(5-(4-(4-chloro-3-fluorobenzyl)-6-methoxy-3,5-dioxo-4,5-dihydro-1,2,4-triazin-2(3H)-yl)-2-fluorophenyl)acetamide (ADX71441). In vitro, Schild plot and reversibility tests at the target confirmed PAM properties of the compound. In mice and rats ADX71441 is bioavailable after oral administration and is brain penetrant. A single dose of ADX71441 had an anxiolytic-like profile in the mouse marble burying test (minimum effective dose; MED 3 mg/kg) as well as in the elevated plus maze test in mice and rats (both MED 3 mg/kg). Also, in mice, acute administration of ADX71441 reduced visceral pain-associated behaviors in the acetic acid-induced writhing test. ADX71441 dose-dependently reduced time on rotarod in rats (MED 10 mg/kg) indicative of muscle-relaxant qualities. ADX71441 reduced locomotor activity in mice (10 mg/kg) and rats (3 mg/kg) after single dose; however, following sub-chronic administration in mice, 30 mg/kg ADX71441 was associated with normal locomotor activity. While acute administration of ADX71441 reduced body temperature in rats and mice (both MED 10 mg/kg), the effect in the former was transient, rapidly returning to normal levels despite high concentrations of the compound remaining in plasma. Thus, the GABAB PAM ADX71441 represents a valid therapeutic approach for development of novel treatment of anxiety, pain and spasticity.
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Affiliation(s)
- Mikhail Kalinichev
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland.
| | - Françoise Girard
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
| | - Hasnaà Haddouk
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
| | - Mélanie Rouillier
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
| | - Eric Riguet
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
| | | | - Vincent Mutel
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
| | - Robert Lütjens
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
| | - Sonia Poli
- Addex Therapeutics SA, Chemin des Mines 9, CH-1202, Geneva, Switzerland
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Shimizu N, Wood S, Kushiro K, Perachio A, Makishima T. The role of GABAB receptors in the vestibular oculomotor system in mice. Behav Brain Res 2016; 302:152-9. [PMID: 26778789 DOI: 10.1016/j.bbr.2016.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 11/28/2022]
Abstract
Systemic administration of a gamma-amino butyric acid type B (GABAB) receptor agonist, baclofen, affects various physiological and psychological processes. To date, the effects on oculomotor system have been well characterized in primates, however those in mice have not been explored. In this study, we investigated the effects of baclofen focusing on vestibular-related eye movements. Two rotational paradigms, i.e. sinusoidal rotation and counter rotation were employed to stimulate semicircular canals and otolith organs in the inner ear. Experimental conditions (dosage, routes and onset of recording) were determined based on the prior studies exploring the behavioral effects of baclofen in mice. With an increase in dosage, both canal and otolith induced ocular responses were gradually affected. There was a clear distinction in the drug sensitivity showing that eye movements derived from direct vestibulo-ocular reflex pathways were relatively unaltered, while the responses through higher-order neural networks in the vestibular system were substantially decreased. These findings were consistent with those observed in primates suggesting a well-conserved role of GABAB receptors in the oculomotor system across frontal-eyed and lateral-eyed animals. We showed here a previously unrecognized effect of baclofen on the vestibular oculomotor function in mice. When interpreting general animal performance under the drug, the potential contribution of altered balance system should be taken into consideration.
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Affiliation(s)
- Naoki Shimizu
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
| | - Scott Wood
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA; Department of Psychology, Azusa Pacific University, Azusa California, USA
| | - Keisuke Kushiro
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Adrian Perachio
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Tomoko Makishima
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
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Savignac HM, Couch Y, Stratford M, Bannerman DM, Tzortzis G, Anthony DC, Burnet PW. Prebiotic administration normalizes lipopolysaccharide (LPS)-induced anxiety and cortical 5-HT2A receptor and IL1-β levels in male mice. Brain Behav Immun 2016; 52:120-131. [PMID: 26476141 PMCID: PMC4927692 DOI: 10.1016/j.bbi.2015.10.007] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 12/26/2022] Open
Abstract
The manipulation of the enteric microbiota with specific prebiotics and probiotics, has been shown to reduce the host's inflammatory response, alter brain chemistry, and modulate anxiety behaviour in both rodents and humans. However, the neuro-immune and behavioural effects of prebiotics on sickness behaviour have not been explored. Here, adult male CD1 mice were fed with a specific mix of non-digestible galacto-oligosaccharides (Bimuno®, BGOS) for 3 weeks, before receiving a single injection of lipopolysaccharide (LPS), which induces sickness behaviour and anxiety. Locomotor and marble burying activities were assessed 4h after LPS injection, and after 24h, anxiety in the light-dark box was assessed. Cytokine expression, and key components of the serotonergic (5-Hydroxytryptamine, 5-HT) and glutamatergic system were evaluated in the frontal cortex to determine the impact of BGOS administration at a molecular level. BGOS-fed mice were less anxious in the light-dark box compared to controls 24h after the LPS injection. Elevated cortical IL-1β concentrations in control mice 28 h after LPS were not observed in BGOS-fed animals. This significant BGOS×LPS interaction was also observed for 5HT2A receptors, but not for 5HT1A receptors, 5HT, 5HIAA, NMDA receptor subunits, or other cytokines. The intake of BGOS did not influence LPS-mediated reductions in marble burying behaviour, and its effect on locomotor activity was equivocal. Together, our data show that the prebiotic BGOS has an anxiolytic effect, which may be related to the modulation of cortical IL-1β and 5-HT2A receptor expression. Our data suggest a potential role for prebiotics in the treatment of neuropsychiatric disorders where anxiety and neuroinflammation are prominent clinical features.
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Affiliation(s)
| | - Yvonne Couch
- Department of Pharmacology, University of Oxford, Oxford OX1, UK
| | - Michael Stratford
- CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, OX3 7DQ, UK
| | - David M. Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford OX1, UK
| | | | | | - Philip W.J. Burnet
- Department of Psychiatry, University of Oxford, Oxford OX3 7JX, UK,Corresponding author at: Neurosciences Building, Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford OX3 7JX, UK.Neurosciences BuildingDepartment of PsychiatryUniversity of OxfordWarneford HospitalOxfordOX3 7JXUK
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11
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Jacobson LH, Sweeney FF, Kaupmann K, O’Leary OF, Gassmann M, Bettler B, Cryan JF. Differential roles of GABAB1 subunit isoforms on locomotor responses to acute and repeated administration of cocaine. Behav Brain Res 2016; 298:12-6. [DOI: 10.1016/j.bbr.2015.10.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
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12
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Brown JW, Moeller A, Schmidt M, Turner SC, Nimmrich V, Ma J, Rueter LE, van der Kam E, Zhang M. Anticonvulsant effects of structurally diverse GABA(B) positive allosteric modulators in the DBA/2J audiogenic seizure test: Comparison to baclofen and utility as a pharmacodynamic screening model. Neuropharmacology 2015; 101:358-69. [PMID: 26471422 DOI: 10.1016/j.neuropharm.2015.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/31/2015] [Accepted: 10/04/2015] [Indexed: 02/02/2023]
Abstract
The GABA(B) receptor has been indicated as a promising target for multiple CNS-related disorders. Baclofen, a prototypical orthosteric agonist, is used clinically for the treatment of spastic movement disorders, but is associated with unwanted side-effects, such as sedation and motor impairment. Positive allosteric modulators (PAM), which bind to a topographically-distinct site apart from the orthosteric binding pocket, may provide an improved side-effect profile while maintaining baclofen-like efficacy. GABA, the major inhibitory neurotransmitter in the CNS, plays an important role in the etiology and treatment of seizure disorders. Baclofen is known to produce anticonvulsant effects in the DBA/2J mouse audiogenic seizure test (AGS), suggesting it may be a suitable assay for assessing pharmacodynamic effects. Little is known about the effects of GABA(B) PAMs, however. The studies presented here sought to investigate the AGS test as a pharmacodynamic (PD) screening model for GABA(B) PAMs by comparing the profile of structurally diverse PAMs to baclofen. GS39783, rac-BHFF, CMPPE, A-1295120 (N-(3-(4-(4-chloro-3-fluorobenzyl)-6-methoxy-3,5-dioxo-4,5-dihydro-1,2,4-triazin-2(3H)-yl)phenyl)acetamide), and A-1474713 (N-(3-(4-(4-chlorobenzyl)-3,5-dioxo-4,5-dihydro-1,2,4-triazin-2(3H)-yl)phenyl)acetamide) all produced robust, dose-dependent anticonvulsant effects; a similar profile was observed with baclofen. Pre-treatment with the GABA(B) antagonist SCH50911 completely blocked the anticonvulsant effects of baclofen and CMPPE in the AGS test, indicating such effects are likely mediated by the GABA(B) receptor. In addition to the standard anticonvulsant endpoint of the AGS test, video tracking software was employed to assess potential drug-induced motor side-effects during the acclimation period of the test. This analysis was sensitive to detecting drug-induced changes in total distance traveled, which was used to establish a therapeutic index (TI = hypoactivity/anticonvulsant effects). Calculated TIs for A-1295120, CMPPE, rac-BHFF, GS39783, and A-1474713 were 5.31x, 5.00x, 4.74x, 3.41x, and 1.83x, respectively, whereas baclofen was <1. The results presented here suggest the DBA/2J mouse AGS test is a potentially useful screening model for detecting PD effects of GABA(B) PAMs and can provide an initial read-out on target-related motor side-effects. Furthermore, an improved TI was observed for PAMs compared to baclofen, indicating the PAM approach may be a viable therapeutic alternative to baclofen.
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Affiliation(s)
- Jordan W Brown
- Neuroscience Discovery, AbbVie, Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States.
| | - Achim Moeller
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Martin Schmidt
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Sean C Turner
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Volker Nimmrich
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Junli Ma
- Drug Metabolism and Pharmacokinetics, AbbVie, Inc., North Chicago, IL 60064, United States
| | - Lynne E Rueter
- Neuroscience Discovery, AbbVie, Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States
| | - Elizabeth van der Kam
- Neuroscience Discovery, AbbVie Deutschland GmbH & Co KG, Knollstrasse, Ludwigshafen 67061, Germany
| | - Min Zhang
- Neuroscience Discovery, AbbVie, Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States
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Kalinichev M, Donovan-Rodriguez T, Girard F, Riguet E, Rouillier M, Bournique B, Haddouk H, Mutel V, Poli S. Evaluation of peripheral versus central effects of GABA(B) receptor activation using a novel, positive allosteric modulator of the GABA(B) receptor ADX71943, a pharmacological tool compound with a fully peripheral activity profile. Br J Pharmacol 2014; 171:4941-54. [PMID: 24923436 DOI: 10.1111/bph.12812] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/27/2014] [Accepted: 06/06/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE The GABA(B) receptor agonist, baclofen, has shown promising effects in patients suffering from pain, post-traumatic stress disorder, alcoholism, overactive bladder and gastroesophageal reflux disease. However, baclofen's short duration of action and side effects limit its wider use. Here we characterized a novel, GABA(B) receptor positive allosteric modulator (PAM) ADX71943. EXPERIMENTAL APPROACH In vitro, ADX71943 was assessed for pharmacological activity and selectivity using recombinant and native GABA(B) receptors. In vivo ADX71943 was assessed in the acetic acid-induced writhing (AAW) test in mice and formalin tests (FTs) in mice and rats. Marble burying (MB) and elevated plus maze (EPM) tests, rotarod, spontaneous locomotor activity (sLMA) and body temperature (BT) tests in mice and rats were used to investigate centrally-mediated effects. KEY RESULTS In vitro, in the presence of GABA, ADX71943 increased the potency and efficacy of agonists and showed selectivity at the GABA(B) receptor. ADX71943 reduced pain-associated behaviours in AAW; an effect blocked by GABA(B) receptor antagonist CGP63360. ADX71943 reduced pain in the FT in mice and rats, but was inactive in the MB and EPM despite reaching high concentrations in plasma. ADX71943 had no effect on BT, rotarod and sLMA. CONCLUSIONS AND IMPLICATIONS ADX71943 showed consistent and target-related efficacy in tests of disorders that have a significant peripheral component (acute and chronic pain), while having no effect in those associated with centrally-mediated anxiety-like reactivity and side effects. Thus, ADX71943 is a useful pharmacological tool for delineation of peripherally- versus centrally-mediated effects of GABA(B) receptor activation.
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Cedillo LN, Miranda F. Effects of co-administration of the GABAB receptor agonist baclofen and a positive allosteric modulator of the GABAB receptor, CGP7930, on the development and expression of amphetamine-induced locomotor sensitization in rats. Pharmacol Rep 2014; 65:1132-43. [PMID: 24399709 DOI: 10.1016/s1734-1140(13)71471-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 05/13/2013] [Indexed: 01/08/2023]
Abstract
BACKGROUND Several of the behavioral effects of amphetamine (AMPH) are mediated by an increase in dopamine neurotransmission in the nucleus accumbens. However, evidence shows that γ-aminobutyric acid B (GABAB) receptors are involved in the behavioral effects of psychostimulants, including AMPH. Here, we examined the effects of co-administration of the GABAB receptor agonist baclofen and a positive allosteric modulator of the GABAB receptor, CGP7930, on AMPH-induced locomotor sensitization. METHODS In a series of experiments, we examined whether baclofen (2.0, 3.0 and 4.0 mg/kg), CGP7930 (5.0, 10.0 and 20.0 mg/kg), or co-administration of CGP7930 (5.0, 10.0 and 20.0 mg/kg) with a lower dose of baclofen (2.0 mg/kg) could prevent the development and expression of locomotor sensitization produced by AMPH (1.0 mg/kg). RESULTS The results showed that baclofen treatment prevented both the development and expression of AMPH-induced locomotor sensitization in a dose-dependent manner. Furthermore, the positive allosteric modulator of the GABAB receptor, CGP7930, increased the effects of a lower dose of baclofen on AMPH-induced locomotor sensitization under both conditions. CONCLUSION These data provide further evidence that GABAB receptor ligands may modulate psychostimulant-induced behaviors.
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Affiliation(s)
- Laura N Cedillo
- FES Iztacala, National Autonomous University of México, Av. de los Barrios 1, Los Reyes Iztacala Tlalnepantla, Edo. de México 54090, México.
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15
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Activation but not blockade of GABAB receptors during early-life alters anxiety in adulthood in BALB/c mice. Neuropharmacology 2014; 81:303-10. [DOI: 10.1016/j.neuropharm.2013.08.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 08/03/2013] [Accepted: 08/30/2013] [Indexed: 11/19/2022]
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16
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Maity B, Stewart A, Yang J, Loo L, Sheff D, Shepherd AJ, Mohapatra DP, Fisher RA. Regulator of G protein signaling 6 (RGS6) protein ensures coordination of motor movement by modulating GABAB receptor signaling. J Biol Chem 2011; 287:4972-81. [PMID: 22179605 DOI: 10.1074/jbc.m111.297218] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
γ-Aminobutyric acid (GABA) release from inhibitory interneurons located within the cerebellar cortex limits the extent of neuronal excitation in part through activation of metabotropic GABA(B) receptors. Stimulation of these receptors triggers a number of downstream signaling events, including activation of GIRK channels by the Gβγ dimer resulting in membrane hyperpolarization and inhibition of neurotransmitter release from presynaptic sites. Here, we identify RGS6, a member of the R7 subfamily of RGS proteins, as a key regulator of GABA(B)R signaling in cerebellum. RGS6 is enriched in the granule cell layer of the cerebellum along with neuronal GIRK channel subunits 1 and 2 where RGS6 forms a complex with known binding partners Gβ(5) and R7BP. Mice lacking RGS6 exhibit abnormal gait and ataxia characterized by impaired rotarod performance improved by treatment with a GABA(B)R antagonist. RGS6(-/-) mice administered baclofen also showed exaggerated motor coordination deficits compared with their wild-type counterparts. Isolated cerebellar neurons natively expressed RGS6, GABA(B)R, and GIRK channel subunits, and cerebellar granule neurons from RGS6(-/-) mice showed a significant delay in the deactivation kinetics of baclofen-induced GIRK channel currents. These results establish RGS6 as a key component of GABA(B)R signaling and represent the first demonstration of an essential role for modulatory actions of RGS proteins in adult cerebellum. Dysregulation of RGS6 expression in human patients could potentially contribute to loss of motor coordination and, thus, pharmacological manipulation of RGS6 levels might represent a viable means to treat patients with ataxias of cerebellar origin.
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Affiliation(s)
- Biswanath Maity
- Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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17
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Schauwecker PE. Strain differences in seizure-induced cell death following pilocarpine-induced status epilepticus. Neurobiol Dis 2011; 45:297-304. [PMID: 21878392 DOI: 10.1016/j.nbd.2011.08.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 07/08/2011] [Accepted: 08/15/2011] [Indexed: 11/18/2022] Open
Abstract
Mouse strains differ from one another in their susceptibility to seizure-induced excitotoxic cell death. Previously, we have demonstrated that mature inbred strains of mice show remarkable genetic differences in susceptibility to the neuropathological consequences of seizures in the kainate model of status epilepticus. At present, while the cellular mechanisms underlying strain-dependent differences in susceptibility remain unclear, some of this variation is assumed to have a genetic basis. However, it remains unclear whether strain differences in susceptibility to seizure-induced cell death observed following kainate administration are observed following systemic administration of other chemoconvulsants. In rodents, the cholinomimetic convulsant pilocarpine is widely used to induce status epilepticus (SE), followed by hippocampal damage and spontaneous recurrent seizures, resembling temporal lobe epilepsy. This model has initially been described in rats, but is increasingly used in mice. We characterized neuronal pathologies after pilocarpine-induced status epilepticus (SE) in eight inbred strains of mice focusing on the hippocampus. A ramping-up dose protocol for pilocarpine was used and behavior was monitored for 4-5 h. While we did not observe any significant differences in seizure latency or duration to pilocarpine among the inbred strains, we did observe a significant difference in susceptibility to the neuropathological consequences of pilocarpine-induced SE. Of the eight genetically diverse mouse strains screened for pilocarpine-induced status, BALB/cJ and BALB/cByJ were the only two strains that were resistant to the neuropathological consequences of seizure-induced cell death. Additional studies of these murine strains may be useful for investigating genetic influences on pilocarpine-induced status epilepticus.
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Affiliation(s)
- P Elyse Schauwecker
- Department of Cell and Neurobiology, USC Keck School of Medicine, 1333 San Pablo Street, BMT 403, Los Angeles, CA 90089-9112, USA.
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Vlachou S, Paterson NE, Guery S, Kaupmann K, Froestl W, Banerjee D, Finn MG, Markou A. Both GABA(B) receptor activation and blockade exacerbated anhedonic aspects of nicotine withdrawal in rats. Eur J Pharmacol 2011; 655:52-8. [PMID: 21262222 DOI: 10.1016/j.ejphar.2011.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 12/07/2010] [Accepted: 01/07/2011] [Indexed: 01/19/2023]
Abstract
Nicotine dependence is maintained by the aversive, depression-like effects of nicotine withdrawal and the rewarding effects of acute nicotine. GABA(B) receptor antagonists exhibit antidepressant-like effects in rodents, whereas GABA(B) receptor agonists attenuate the rewarding effects of nicotine. Recent studies with GABA(B) receptor positive modulators showed that these compounds represent potentially improved medications for the treatment of nicotine dependence because of fewer side-effects than GABA(B) receptor agonists. Thus, GABA(B) receptor agonists and antagonists, and GABA(B) receptor positive modulators may have efficacy as smoking cessation aids by targeting different aspects of nicotine dependence and withdrawal. The present study assessed the effects of the GABA(B) receptor agonist CGP44532, the GABA(B) receptor antagonist CGP56433A, and the GABA(B) receptor positive modulator BHF177 on the anhedonic aspects of nicotine withdrawal. Rats were prepared with stimulating electrodes in the posterior lateral hypothalamus. After establishing stable intracranial self-stimulation (ICSS) thresholds, rats were prepared with subcutaneous osmotic minipumps delivering either nicotine or saline for 7 or 14days. ICSS thresholds were assessed 6h post-pump removal. Thirty hours after pump removal, CGP44532, CGP56433A, and BHF177 were administered 30min prior to ICSS testing. Both GABA(B) receptor activation (CGP44532 and BHF177) and blockade (CGP56433A) elevated ICSS thresholds in all groups, resulting in exacerbated effects of nicotine withdrawal in the nicotine-treated groups. These similar effects of GABA(B) receptor activation and blockade on the anhedonic depression-like aspects of nicotine withdrawal were surprising and perhaps reflect differential efficacy of these compounds at presynaptic hetero- and autoreceptors, as well as postsynaptic, GABA(B) receptors.
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Affiliation(s)
- Styliani Vlachou
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA 92093-0603, USA
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Koek W, France CP, Cheng K, Rice KC. GABAB receptor-positive modulators: enhancement of GABAB receptor agonist effects in vivo. J Pharmacol Exp Ther 2010; 335:163-71. [PMID: 20628000 PMCID: PMC2957789 DOI: 10.1124/jpet.110.171116] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 07/13/2010] [Indexed: 12/20/2022] Open
Abstract
In vivo effects of GABA(B) receptor-positive modulators suggest that they have therapeutic potential for treating central nervous system disorders such as anxiety, depression, and drug abuse. Although these effects generally are thought to be mediated by positive modulation of GABA(B) receptors, such modulation has been examined primarily in vitro. The present study was aimed at further examining the in vivo positive modulatory properties of the GABA(B) receptor-positive modulators, 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl) phenol (CGP7930) and (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF). Both compounds enhanced loss of righting induced by baclofen in mice. However, CGP7930 was less effective and rac-BHFF was less potent for enhancing loss of righting induced by γ-hydroxybutyrate (GHB), which, like baclofen, has GABA(B) receptor agonist properties. In contrast with baclofen- and GHB-induced loss of righting, the hypothermic effects of baclofen and GHB were not enhanced by rac-BHFF but were enhanced by CGP7930 only at doses that produced hypothermia when given alone. CGP7930-induced hypothermia was not attenuated by the GABA(B) receptor antagonist 3-aminopropyl(diethoxymethyl)phosphinic acid (CGP35348), at doses that blocked baclofen-induced hypothermia, and was not increased by the nitric-oxide synthase inhibitor N(ω)-nitro-L-arginine methyl ester, at doses that increased the hypothermic effects of baclofen and GHB. The results provide evidence that CGP7930 and rac-BHFF act in vivo as positive modulators at GABA(B) receptors mediating loss of righting, but not at GABA(B) receptors mediating hypothermia. Conceivably, CGP7930, but not rac-BHFF, acts as an allosteric agonist at these latter receptors. Taken together, the results provide further evidence of pharmacologically distinct GABA(B) receptor subtypes, possibly allowing for a more selective therapeutic interference with the GABA(B) system.
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Affiliation(s)
- Wouter Koek
- Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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Voigt RM, Herrold AA, Riddle JL, Napier TC. Administration of GABA(B) receptor positive allosteric modulators inhibit the expression of previously established methamphetamine-induced conditioned place preference. Behav Brain Res 2010; 216:419-23. [PMID: 20804788 DOI: 10.1016/j.bbr.2010.08.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/17/2010] [Accepted: 08/20/2010] [Indexed: 12/18/2022]
Abstract
Little is known about the role of GABA(B) receptors (GABA(B)Rs) in the maintenance of memories associated with using abused substances. We have embarked on a series of studies designed to determine if enhancing the efficacy of GABA-occupied GABA(B)Rs with positive allosteric modulators (PAMs) can negate previously established conditioned place preference (CPP) induced by methamphetamine. In the current study, we evaluated the effects of acute administration of GABA(B)R PAMs, GS39783 and CGP7930. We determined that post-conditioning treatments with these PAMs, administered in the home cage, blocked the subsequent expression of methamphetamine-induced CPP. These data indicate that selectively augmenting GABA-occupied GABA(B)R signaling is sufficient to reduce memory maintenance and/or the salience of contextual cues previously associated with methamphetamine.
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Affiliation(s)
- Robin M Voigt
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612, United States.
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Cryan JF, Slattery DA. GABAB Receptors and Depression: Current Status. GABABRECEPTOR PHARMACOLOGY - A TRIBUTE TO NORMAN BOWERY 2010; 58:427-51. [DOI: 10.1016/s1054-3589(10)58016-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Sunyer B, An G, Kang SU, Höger H, Lubec G. Strain-dependent hippocampal protein levels of GABAB-receptor subunit 2 and NMDA-receptor subunit 1. Neurochem Int 2009; 55:253-6. [DOI: 10.1016/j.neuint.2009.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 03/10/2009] [Indexed: 10/21/2022]
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Abstract
Anxiety disorders are a growing health problem world-wide. However, the causative factors, etiology, and underlying mechanisms of anxiety disorders, as for most psychiatric disorders, remain relatively poorly understood. The current status of clinical research indicates that anxiety traits and anxiety disorder in man have a genetic component, and therefore genetic modeling in animals is a logical approach to gain a greater insight into their neurobiology. However, it is also clear that the nature of these genetic contributions is highly complex. Moreover, the success of this approach is largely contingent upon the utility of available behavioral paradigms for modeling anxiety-related behaviors in mice. Animal genetic models provide a unique and comprehensive methodological tool to aid discovery into the etiology, neurobiology, and ultimately, the therapy of human anxiety disorders. The approach, however, is challenged with a number of complexities. In particular, the heterogeneous nature of anxiety disorders in man coupled with the associated multifaceted and descriptive diagnostic criteria, create challenges in both animal modeling and in clinical research. In this article, we describe some of the powerful modem genetic techniques that are uniquely amenable to the laboratory mouse and thus provide a strategy for approaching some of these challenges. Moreover, we focus on recent advances which have highlighted the relative contribution of genetic modeling in animals to the understanding of underlying neurobiology and genetic basis of anxiety disorders.
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Pravetoni M, Wickman K. Behavioral characterization of mice lacking GIRK/Kir3 channel subunits. GENES BRAIN AND BEHAVIOR 2008; 7:523-31. [PMID: 18194467 DOI: 10.1111/j.1601-183x.2008.00388.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
G protein-gated inwardly rectifying K(+) (GIRK/Kir3) channels mediate the postsynaptic inhibitory effects of many neurotransmitters and drugs of abuse. The lack of drugs selective for GIRK channels has hindered our ability to study their contributions to behavior. Here, we assessed the impact of GIRK subunit ablation on several behavioral endpoints. Mice were evaluated with respect to open-field motor activity and habituation, anxiety-related behavior, motor co-ordination and ataxia and operant performance. GIRK3 knockout ((-/-)) mice behaved indistinguishably from wild-type mice in this panel of tests. GIRK1(-/-) mice and GIRK2(-/-) mice, however, showed elevated motor activity and delayed habituation to an open field. GIRK2(-/-) mice, and to a lesser extent GIRK1(-/-) mice, also displayed reduced anxiety-related behavior in the elevated plus maze. Both GIRK1(-/-) mice and GIRK2(-/-) mice displayed marked resistance to the ataxic effects of the GABA(B) receptor agonist baclofen in the rotarod test. All GIRK(-/-) mice were able to learn an operant task using food as the reinforcing agent. Within-session progressive ratio scheduling, however, showed elevated lever press behavior in GIRK2(-/-) mice and, to a lesser extent, in GIRK1(-/-) mice. Phenotypic differences between mice lacking GIRK1, GIRK2 and GIRK3 correlate well with the known impact of GIRK subunit ablation on neurotransmitter-gated GIRK currents, arguing that most neuronal GIRK channels contain GIRK1 and/or GIRK2. Altogether, our data suggest that GIRK channels make important contribution to a range of behaviors and may represent points of therapeutic intervention in disorders of anxiety, spasticity and reward.
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Affiliation(s)
- M Pravetoni
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
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Malherbe P, Masciadri R, Norcross RD, Knoflach F, Kratzeisen C, Zenner MT, Kolb Y, Marcuz A, Huwyler J, Nakagawa T, Porter RHP, Thomas AW, Wettstein JG, Sleight AJ, Spooren W, Prinssen EP. Characterization of (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one as a positive allosteric modulator of GABAB receptors. Br J Pharmacol 2008; 154:797-811. [PMID: 18536733 DOI: 10.1038/bjp.2008.135] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE As baclofen is active in patients with anxiety disorders, GABAB receptors have been implicated in the modulation of anxiety. To avoid the side effects of baclofen, allosteric enhancers of GABAB receptors have been studied to provide an alternative therapeutic avenue for modulation of GABAB receptors. The aim of this study was to characterize derivatives of (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) as enhancers of GABAB receptors. EXPERIMENTAL APPROACH Enhancing properties of rac-BHFF were assessed in the Chinese hamster ovary (CHO)-Galpha16-hGABA(B1a,2a) cells by Fluorometric Imaging Plate Reader and GTPgamma[35S]-binding assays, and in rat hippocampal slices by population spike (PS) recordings. In vivo activities of rac-BHFF were assessed using the loss of righting reflex (LRR) and stress-induced hyperthermia (SIH) models. KEY RESULTS In GTPgamma[35S]-binding assays, 0.3 microM rac-BHFF or its pure enantiomer (+)-BHFF shifted the GABA concentration-response curve to the left, an effect that resulted in a large increase in both GABA potency (by 15.3- and 87.3-fold) and efficacy (149% and 181%), respectively. In hippocampal slices, rac-BHFF enhanced baclofen-induced inhibition of PS of CA1 pyramidal cells. In an in vivo mechanism-based model in mice, rac-BHFF increased dose-dependently the LRR induced by baclofen with a minimum effective dose of 3 mg kg(-1) p.o. rac-BHFF (100 mg kg(-1) p.o.) tested alone had no effect on LRR nor on spontaneous locomotor activity, but exhibited anxiolytic-like activity in the SIH model in mice. CONCLUSIONS AND IMPLICATIONS rac-BHFF derivatives may serve as valuable pharmacological tools to elucidate the pathophysiological roles played by GABAB receptors in the central and peripheral nervous systems.
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Affiliation(s)
- P Malherbe
- Discovery Research CNS, F Hoffmann-La Roche Ltd, Basel, Switzerland.
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5-HT2C and GABAB receptors influence handling-induced convulsion severity in chromosome 4 congenic and DBA/2J background strain mice. Brain Res 2008; 1198:124-31. [PMID: 18262506 DOI: 10.1016/j.brainres.2008.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 12/21/2007] [Accepted: 01/05/2008] [Indexed: 11/21/2022]
Abstract
Progress towards elucidating the underlying genetic variation for susceptibility to complex central nervous system (CNS) hyperexcitability states has just begun. Genetic mapping analyses suggest that a gene(s) on mid-chromosome 4 has pleiotropic effects on multiple CNS hyperexcitability states in mice, including alcohol and barbiturate withdrawal and convulsions elicited by chemical and audiogenic stimuli. We recently identified Mpdz within this chromosomal region as a gene that influences alcohol and barbiturate withdrawal convulsions. Mpdz encodes the multi-PDZ domain protein (MPDZ). Currently, there is limited information available about the mechanism by which MPDZ influences drug withdrawal and/or other CNS hyperexcitability states, but may involve its interaction with 5-HT2C and/or GABAB receptors. One of the most useful tools we have developed thus far is a congenic strain that possesses a segment of chromosome 4 from the C57BL/6J (donor) mouse strain superimposed on a genetic background that is >99% from the DBA/2J strain. The introduced segment spans the Mpdz gene. Here, we demonstrate that handling-induced convulsions are less severe in congenic vs. background strain mice in response to either a 5-HT2C receptor antagonist (SB242084) or a GABAB receptor agonist (baclofen), but not a GABAA receptor channel blocker (pentylenetetrazol). These data suggest that allelic variation in Mpdz, or a linked gene, influences SB242084- and baclofen-enhanced convulsions. Our results are consistent with the hypothesis that Mpdz's effects on CNS hyperexcitability, including alcohol and barbiturate withdrawal, involve MPDZ interaction with 5-HT2C and/or GABAB receptors. However, additional genes reside within the congenic interval and may also influence CNS hyperexcitability.
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Jacobson LH, Cryan JF. Evaluation of the anxiolytic-like profile of the GABAB receptor positive modulator CGP7930 in rodents. Neuropharmacology 2008; 54:854-62. [PMID: 18328507 DOI: 10.1016/j.neuropharm.2008.01.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 11/28/2007] [Accepted: 01/05/2008] [Indexed: 11/26/2022]
Abstract
There is a growing body of data to support the notion that GABA(B) receptors may be a therapeutic target for anxiety disorders. However, the application of GABA(B) receptor agonists in anxiety research and psychiatry is hampered by side effects that include motor in-coordination and hypothermia. Recently the GABA(B) receptor positive modulator GS39783 was shown to be anxiolytic in rodent models, but was devoid of accompanying side effects characteristic of full agonists. However, it is important to test whether such anxiolytic effects generalise to another chemical class of GABA(B) receptor positive modulators. We therefore aimed to investigate the anxiolytic and side-effect profile of CGP7930, the first-reported GABA(B) receptor positive modulator, in rodent models of anxiety, motor coordination and hypothermia. CGP7930 (3-300 mg/kg) showed a modest, compared to the benzodiazepine chlordiazepoxide (10mg/kg), dose-dependent anxiolytic profile in the mouse stress-induced hyperthermia (100mg/kg), staircase (100 and 300 mg/kg) and elevated zero maze tests (3-100mg/kg), but did not have any anxiolytic effects in the rat elevated plus maze. Similar to GS39783, CGP7930 also demonstrated a greatly reduced side-effect profile in comparison to the GABA(B) receptor full agonist baclofen in the mouse rotarod and traction wire tests and did not induce hypothermia. Although the effects of CGP7930 were modest, these results represent a second, structurally distinct, class of GABA(B) positive modulators showing anxiolytic activity. As such, these data support the premise that GABA(B) receptor positive modulation represents a novel therapeutic strategy for the development of anxiolytic drugs with a superior side-effect profile. The generation of more potent compounds is now warranted.
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Affiliation(s)
- Laura H Jacobson
- Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland
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Lhuillier L, Mombereau C, Cryan JF, Kaupmann K. GABA(B) receptor-positive modulation decreases selective molecular and behavioral effects of cocaine. Neuropsychopharmacology 2007; 32:388-98. [PMID: 16710312 PMCID: PMC1774586 DOI: 10.1038/sj.npp.1301102] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Exposure to cocaine induces selective behavioral and molecular adaptations. In rodents, acute cocaine induces increased locomotor activity, whereas prolonged drug exposure results in behavioral locomotor sensitization, which is thought to be a consequence of drug-induced neuroadaptive changes. Recent attention has been given to compounds activating GABA(B) receptors as potential antiaddictive therapies. In particular, the principle of allosteric positive GABA(B) receptor modulators is very promising in this respect, as positive modulators lack the sedative and muscle relaxant properties of full GABA(B) receptor agonists such as baclofen. Here, we investigated the effects of systemic application of the GABA(B) receptor-positive modulator GS39783 (N,N'-dicyclopentyl-2-methylsulfanyl-5-nitro-pyrimidine-4, 6-diamine) in animals treated with acute and chronic cocaine administration. Both GS39783 and baclofen dose dependently attenuated acute cocaine-induced hyperlocomotion. Furthermore, both compounds also efficiently blocked cocaine-induced Fos induction in the striatal complex. In chronic studies, GS39783 induced a modest attenuation of cocaine-induced locomotor sensitization. Chronic cocaine induces the accumulation of the transcription factor deltaFosB and upregulates cAMP-response-element-binding protein (CREB) and dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32). GS39783 blocked the induction/activation of DARPP-32 and CREB in the nucleus accumbens and dorsal striatum and partially inhibited deltaFosB accumulation in the dorsal striatum. In summary, our data provide evidence that GS39783 attenuates the acute behavioral effects of cocaine exposure in rodents and in addition prevents the induction of selective long-term adaptive changes in dopaminergic signaling pathways. Further investigation of GABA(B) receptor-positive modulation as a novel therapeutic strategy for the treatment of cocaine dependence and possibly other drugs of abuse is therefore warranted.
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Affiliation(s)
| | | | - John F. Cryan
- *Corresponding authors: JF Cryan & K Kaupmann, Novartis Institutes for BioMedical Research; Novartis Pharma AG; CH 4002 Basel, Switzerland; please address correspondence to KK () or JFC ()
| | - Klemens Kaupmann
- *Corresponding authors: JF Cryan & K Kaupmann, Novartis Institutes for BioMedical Research; Novartis Pharma AG; CH 4002 Basel, Switzerland; please address correspondence to KK () or JFC ()
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Mombereau C, Lhuillier L, Kaupmann K, Cryan JF. GABAB Receptor-Positive Modulation-Induced Blockade of the Rewarding Properties of Nicotine Is Associated with a Reduction in Nucleus Accumbens ΔFosB Accumulation. J Pharmacol Exp Ther 2007; 321:172-7. [PMID: 17215447 DOI: 10.1124/jpet.106.116228] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
There is an increasing demand for a novel non-nicotinic, nondopaminergic therapeutic approach to nicotine addiction. GABAergic mechanisms have been implicated in drug dependence. Recently, a novel GABAB receptor allosteric-positive modulator, GS39783, was characterized. There are no investigations to date on the effects of GABAB receptor-positive modulators in animal models of nicotine reinforcement. Conditioned place preference (CPP) paradigms are based on the principle that animals, like humans, would learn to seek environmental stimuli that have been previously associated with rewarding events. Here we show that nicotine (0.06 mg/kg s.c.) induced a robust CPP response. Furthermore, GS39783 (30-100 mg/kg p.o.) during the conditioning phase blocked the rewarding effects of nicotine in the CPP paradigm in rats. However, GS39783 did not significantly alter the CPP effects of nicotine when given only immediately before the CPP test. A growing body of evidence suggests that repeated administration of drugs of abuse induced long-term molecular changes in brain plasticity, most notably an accumulation of DeltaFosB, in the striatal complex that contribute to the manifestation of dependence. There was a significant accumulation of DeltaFosB in the nucleus accumbens, but not in the dorsal striatum, of rats treated daily for 5 days with nicotine (0.06 mg/kg i.p.). GS39783 completely (30-100 mg/kg p.o.) counteracted these nicotine-induced molecular adaptations when given before the CPP acquisition phase but not when administered immediately before the test phase. Taken together, the behavioral and molecular changes induced by nicotine occur in concert and are concomitantly amenable to reversal by GABAB receptor-positive modulators.
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Affiliation(s)
- Cedric Mombereau
- Neuroscience Research, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
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30
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Jacobson LH, Bettler B, Kaupmann K, Cryan JF. GABAB1 receptor subunit isoforms exert a differential influence on baseline but not GABAB receptor agonist-induced changes in mice. J Pharmacol Exp Ther 2006; 319:1317-26. [PMID: 16990508 DOI: 10.1124/jpet.106.111971] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
GABA(B) receptor agonists produce hypothermia and motor incoordination. Two GABA(B(1)) receptor subunit isoforms exist, but because of lack of specific molecular or pharmacological tools, the relevance of these isoforms in controlling basal body temperature, locomotor activity, or in vivo responses to GABA(B) receptor agonists has been unknown. Here, we used mice deficient in the GABA(B(1a)) and GABA(B(1b)) subunit isoforms to examine the influence of these isoforms on both baseline motor behavior and body temperature and on the motor-incoordinating and hypothermic responses to the GABA(B) receptor agonists l-baclofen and gamma-hydroxybutyrate (GHB). GABA(B(1b))(-/-) mice were hyperactive in a novel environment and showed slower habituation than either GABA(B(1a))(-/-) or wild-type mice. GABA(B(1b))(-/-) mice were hyperactive throughout the circadian dark phase. Hypothermia in response to l-baclofen (6 and 12 mg/kg) or GHB (1 g/kg), baclofen-induced ataxia as determined on the fixed-speed Rotarod, and GHB-induced hypolocomotion were significantly, but for the most part similarly, attenuated in both GABA(B(1a))(-/-) and GABA(B(1b))(-/-) mice. We conclude that l-baclofen and GHB are nonselective for either GABA(B(1)) receptor isoform in terms of in vivo responses. However, GABA(B(1)) receptor isoforms have distinct and different roles in mediating locomotor behavioral responses to a novel environment. Therefore, GABA(B(1a)) and GABA(B(1b)) isoforms are functionally relevant molecular variants of the GABA(B(1)) receptor subunit, which are differentially involved in specific neurophysiological processes and behaviors.
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Affiliation(s)
- Laura H Jacobson
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
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31
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Contino G, Novelli G. Hereditary spastic paraplegia: clinical genomics and pharmacogenetic perspectives. Expert Opin Pharmacother 2006; 7:1849-56. [PMID: 17020412 DOI: 10.1517/14656566.7.14.1849] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hereditary spastic paraplegias (HSPs) are a group of single-gene disorders characterised by degeneration of the corticospinal tract axons, leading to bilateral, symmetrical, slowly-progressive spastic paraparesis, predominantly of the lower extremities. So far, ~ 30 different chromosomal HSP loci have been identified by genetic linkage analysis. Defects in intracellular trafficking and transport in myelination and abnormalities of mitochondrial proteins have been involved in HSP pathogenesis. At present, treatment of the HSPs is primarily directed symptomatically toward reducing muscle spasticity. Yet, recent progresses in the identification of HSP mutations are providing formidable tools to pharmacogenetic approaches of drug discovery, validation and prediction of individual response.
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Jacobson LH, Cryan JF. Feeling strained? Influence of genetic background on depression-related behavior in mice: a review. Behav Genet 2006; 37:171-213. [PMID: 17029009 DOI: 10.1007/s10519-006-9106-3] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 08/11/2006] [Indexed: 02/03/2023]
Abstract
Depression is a growing pandemic in developed societies. The use of inbred mouse strains in pre-clinical psychiatric research has proven to be a valuable resource. Firstly, they provide the background for genetic manipulations that aid in the discovery of molecular pathways that may be involved in major depression. Further, inbred mouse strains are also being used in the determination of genetic and environmental influences that may pre-dispose or trigger depression-related behavior. This review aims to highlight the utility of inbred mouse strains in depression research, while providing an overview of the current state of research into behavioral differences between strains in paradigms commonly used in the field. Neurochemical differences that may underlie strain differences are examined, and some caveats and cautions associated with the use of inbred strains are highlighted.
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Affiliation(s)
- L H Jacobson
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, CH-4002, Basel, Switzerland
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Abstract
Metabotropic gamma-aminobutyric acid(B) (GABAB) receptors for the major inhibitory transmitter GABA, together with metabotropic glutamate (mGLuRs) receptors, the extracellular calcium-sensing receptors (CaSRs), some V2R pheromone receptors and T1R taste receptors, belong to the family of 3 G-protein-coupled receptors (GPCRs). GABAB receptors are known to control neuronal excitability and modulate synaptic neurotransmission, playing a very important role in many physiological activities. These receptors are widely expressed and distributed in the nervous system and have been implicated in a variety of neurodegenerative and pathophysiological disorders including epilepsy, spasticity, chronic pain, depression, schizophrenia and drug addiction. To form a functional receptor entity, GABAB receptors must exist as a heterodimer consisting of GABAB1 and GABAB2 receptor subtypes with two 7-transmembrane proteins, and these subunits arise from distinct genes. The GABAB1 subunit binds the endogenous ligand within its extracellular N-terminus, whilst the GABAB2 subunit is not only essential for the correct trafficking of the GABAB1 subunit to the cell surface, but is also responsible for the interaction of the receptor with its cognate G-protein. Allosteric modulation has recently been recognized as an alternative pharmacological approach to gain selectivity in drug action. It is now generally accepted that modulators acting at the allosteric sites provide a novel perspective for the development of subtype-selective agents acting at GPCRs. These agents interact with allosteric binding sites quite separate from the highly conserved agonist binding region. In this review, we present a new class of phenylalkylamines, based on the lead compound fendiline, that are potent positive potentiators of GABAB receptor-mediated function and discuss their putative clinical applications. It is proposed that these new modulators may have therapeutic value in GABAB receptor pharmacology and are capable of selectively modifying GABAB receptor function. The allosteric modulators are offering an attractive and novel means to identify new leads, that are devoid of side effects associated with GABAB receptor agonists, and may, therefore, represent a major advance in the drug discovery process.
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Affiliation(s)
- Jennifer Ong
- Department of Anaesthesia and Intensive Care, The University of Adelaide, Australia.
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Slattery DA, Cryan JF. The role of GABAB receptors in depression and antidepressant-related behavioural responses. Drug Dev Res 2006. [DOI: 10.1002/ddr.20110] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Slattery DA, Markou A, Froestl W, Cryan JF. The GABAB receptor-positive modulator GS39783 and the GABAB receptor agonist baclofen attenuate the reward-facilitating effects of cocaine: intracranial self-stimulation studies in the rat. Neuropsychopharmacology 2005; 30:2065-72. [PMID: 15841108 DOI: 10.1038/sj.npp.1300734] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There is an increasing interest in the development of nondopaminergic pharmacotherapies for cocaine abuse. Emerging preclinical and clinical data with the metabotropic GABAB receptor agonist baclofen support a role for the modulation of GABAB receptors in the treatment of drug addiction. Nevertheless, the muscle relaxant, hypothermic, and sedative properties of baclofen somewhat limit its widespread potential therapeutic utility. Recently, positive modulators of the GABAB receptor such as GS39783 (N,N'-dicyclopentyl-2-methylsulfanyl-5-nitro-pyrimidine-4,6-diamine) have been identified. These positive modulators enhance the effects of GABA (gamma-aminobutyric acid) through actions at an allosteric site and are devoid of intrinsic agonistic efficacy. The aim of the present study was to assess the ability of the novel GABAB-positive modulator GS39873 or baclofen to modulate the behavioral effects of cocaine. Drugs of abuse such as cocaine lower brain reward thresholds obtained using intracranial self-stimulation (ICSS). We demonstrate here that GS39783 had no intrinsic effects on ICSS reward thresholds (10-100 mg/kg p.o.) in rats, whereas the full GABAB receptor agonist baclofen (2.5-5 mg/kg p.o.) dose dependently elevated thresholds. Moreover, both GS39783 and baclofen attenuated the threshold lowering effect of cocaine administration (10 mg/kg intraperitoneally) in a dose-related manner. These data strongly suggest that activation of GABAB receptors attenuates the rewarding effects of acute cocaine. Therefore, GABAB-positive modulation may represent a novel therapeutic strategy for the treatment of cocaine dependence and possibly other drugs of abuse without the side effects of full GABAB receptor agonists.
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Affiliation(s)
- David A Slattery
- Psychiatry Program, Neuroscience Research, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
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