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LaCrosse AL, May CE, Griffin WC, Olive MF. mGluR5 positive allosteric modulation prevents MK-801 induced increases in extracellular glutamate in the rat medial prefrontal cortex. Neuroscience 2024; 555:83-91. [PMID: 39019391 DOI: 10.1016/j.neuroscience.2024.06.016] [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: 01/29/2024] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 07/19/2024]
Abstract
Potentiation of metabotropic glutamate receptor subtype 5 (mGluR5) function produces antipsychotic-like and pro-cognitive effects in animal models of schizophrenia and can reverse cognitive deficits induced by N-methyl-D-aspartate type glutamate receptor (NMDAR) antagonists. However, it is currently unknown if mGluR5 positive allosteric modulators (PAMs) can modulate NMDAR antagonist-induced alterations in extracellular glutamate levels in regions underlying these cognitive and behavioral effects, such as the medial prefrontal cortex (mPFC). We therefore assessed the ability of the mGluR5 PAM, 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB), to reduce elevated extracellular glutamate levels induced by the NMDAR antagonist, dizocilpine (MK-801), in the mPFC. Male Sprague-Dawley rats were implanted with a guide cannula aimed at the mPFC and treated for ten consecutive days with MK-801 and CDPPB or their corresponding vehicles. CDPPB or vehicle was administered thirty minutes before MK-801 or vehicle each day. On the final day of treatment, in vivo microdialysis was performed, and samples were collected every thirty minutes to analyze extracellular glutamate levels. Compared to animals receiving only vehicle, administration of MK-801 alone significantly increased extracellular levels of glutamate in the mPFC. This effect was not observed in animals administered CDPPB before MK-801, nor in those administered CDPPB alone, indicating that CDPPB decreased extracellular glutamate release stimulated by MK-801. Results indicate that CDPPB attenuates MK-801 induced elevations in extracellular glutamate in the mPFC. This effect of CDPPB may underlie neurochemical adaptations associated with the pro-cognitive effects of mGluR5 PAMs in rodent models of schizophrenia.
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Affiliation(s)
- Amber L LaCrosse
- Department of Psychology, Arizona State University, 950 S. McAllister Ave., Tempe, AZ 85281, United States; Department of Psychological Science, Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855, United States.
| | - Christina E May
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, MSC 861, 67 President Street, Charleston, SC 29425, United States; Department of Neuroscience and Physiology, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, United States
| | - William C Griffin
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, MSC 861, 67 President Street, Charleston, SC 29425, United States
| | - M Foster Olive
- Department of Psychology, Arizona State University, 950 S. McAllister Ave., Tempe, AZ 85281, United States
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2
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Frankowska M, Smaga I, Gawlińska K, Pieniążek R, Filip M. Further proof on the role of accumbal nNOS in cocaine-seeking behavior in rats. Pharmacol Rep 2024; 76:338-347. [PMID: 38480667 DOI: 10.1007/s43440-024-00571-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/29/2024] [Accepted: 02/02/2024] [Indexed: 04/16/2024]
Abstract
BACKGROUND Cocaine use disorder (CUD) remains a severe health problem with no effective pharmacological therapy. One of the potential pharmacological strategies for CUD pharmacotherapy includes manipulations of the brain glutamatergic (Glu) system which is particularly involved in drug withdrawal and relapse. Previous research indicated a pivotal role of ionotropic N-methyl-D-aspartate (NMDA) receptors or metabotropic receptors' type 5 (mGlu5) receptors in controlling the reinstatement of cocaine. Stimulation of the above molecules results in the activation of the downstream signaling targets such as neuronal nitric oxide synthase (nNOS) and the release of nitric oxide. METHODS In this paper, we investigated the molecular changes in nNOS in the prefrontal cortex and nucleus accumbens following 3 and 10 days of cocaine abstinence as well as the effectiveness of nNOS blockade with the selective enzyme inhibitor N-ω-propyl-L-arginine hydrochloride (L-NPA) on cocaine seeking in male rats. The effect of L-NPA on locomotor activity in drug-naïve animals was investigated. RESULTS Ten-day (but not 3-day) cocaine abstinence from cocaine self-administration increased nNOS gene and protein expression in the nucleus accumbens, but not in the prefrontal cortex. L-NPA (0.5-5 mg/kg) administered peripherally did not change locomotor activity but attenuated the reinstatement induced with cocaine priming or the drug-associated conditioned cue. CONCLUSIONS Our findings support accumbal nNOS as an important molecular player for cocaine seeking while its inhibitors could be considered as anti-cocaine pharmacological tools in male rats.
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Affiliation(s)
- Małgorzata Frankowska
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
| | - Irena Smaga
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Kinga Gawlińska
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Renata Pieniążek
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Małgorzata Filip
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
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Mellios N, Papageorgiou G, Gorgievski V, Maxson G, Hernandez M, Otero M, Varangis M, Dell'Orco M, Perrone-Bizzozero N, Tzavara E. Regulation of neuronal circHomer1 biogenesis by PKA/CREB/ERK-mediated pathways and effects of glutamate and dopamine receptor blockade. RESEARCH SQUARE 2024:rs.3.rs-3547375. [PMID: 38260249 PMCID: PMC10802743 DOI: 10.21203/rs.3.rs-3547375/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
There are currently only very few efficacious drug treatments for SCZ and BD, none of which can significantly ameliorate cognitive symptoms. Thus, further research is needed in elucidating molecular pathways linked to cognitive function and antipsychotic treatment. Circular RNAs (circRNAs) are stable brain-enriched non-coding RNAs, derived from the covalent back-splicing of precursor mRNA molecules. CircHomer1 is a neuronal-enriched, activity-dependent circRNA, derived from the precursor of the long HOMER1B mRNA isoform, which is significantly downregulated in the prefrontal cortex of subjects with psychosis and is able to regulate cognitive function. Even though its relevance to psychiatric disorders and its role in brain function and synaptic plasticity have been well established, little is known about the molecular mechanisms that underlie circHomer1 biogenesis in response to neuronal activity and psychiatric drug treatment. Here we suggest that the RNA-binding protein (RBP) FUS positively regulates neuronal circHomer1 expression. Furthermore, we show that the MEK/ERK and PKA/CREB pathways positively regulate neuronal circHomer1 expression, as well as promote the transcription of Fus and Eif4a3, another RBP previously shown to activate circHomer1 biogenesis. We then demonstrate via both in vitro and in vivo studies that NMDA and mGluR5 receptors are upstream modulators of circHomer1 expression. Lastly, we report that in vivo D2R antagonism increases circHomer1 expression, whereas 5HT2AR blockade reduces circHomer1 levels in multiple brain regions. Taken together, this study allows us to gain novel insights into the molecular circuits that underlie the biogenesis of a psychiatric disease-associated circRNA.
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Janus A, Lustyk K, Pytka K. MK-801 and cognitive functions: Investigating the behavioral effects of a non-competitive NMDA receptor antagonist. Psychopharmacology (Berl) 2023; 240:2435-2457. [PMID: 37725119 PMCID: PMC10640442 DOI: 10.1007/s00213-023-06454-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/21/2023] [Indexed: 09/21/2023]
Abstract
RATIONALE MK-801 (dizocilpine) is a non-competitive NMDA receptor antagonist originally explored for anticonvulsant potential. Despite its original purpose, its amnestic properties led to the development of pivotal models of various cognitive impairments widely employed in research and greatly impacting scientific progress. MK-801 offers several advantages; however, it also presents drawbacks, including inducing dose-dependent hyperlocomotion or ambiguous effects on anxiety, which can impact the interpretation of behavioral research results. OBJECTIVES The present review attempts to summarize and discuss the effects of MK-801 on different types of memory and cognitive functions in animal studies. RESULTS A plethora of behavioral research suggests that MK-801 can detrimentally impact cognitive functions. The specific effect of this compound is influenced by variables including developmental stage, gender, species, strain, and, crucially, the administered dose. Notably, when considering the undesirable effects of MK-801, doses up to 0.1 mg/kg were found not to induce stereotypy or hyperlocomotion. CONCLUSION Dizocilpine continues to be of significant importance in preclinical research, facilitating the exploration of various procognitive therapeutic agents. However, given its potential undesirable effects, it is imperative to meticulously determine the appropriate dosages and conduct supplementary evaluations for any undesirable outcomes, which could complicate the interpretation of the findings.
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Affiliation(s)
- Anna Janus
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688, Krakow, Poland
| | - Klaudia Lustyk
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688, Krakow, Poland
| | - Karolina Pytka
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688, Krakow, Poland.
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Bauminger H, Gaisler-Salomon I. Beyond NMDA Receptors: Homeostasis at the Glutamate Tripartite Synapse and Its Contributions to Cognitive Dysfunction in Schizophrenia. Int J Mol Sci 2022; 23:8617. [PMID: 35955750 PMCID: PMC9368772 DOI: 10.3390/ijms23158617] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 02/01/2023] Open
Abstract
Cognitive deficits are core symptoms of schizophrenia but remain poorly addressed by dopamine-based antipsychotic medications. Glutamate abnormalities are implicated in schizophrenia-related cognitive deficits. While the role of the NMDA receptor has been extensively studied, less attention was given to other components that control glutamate homeostasis. Glutamate dynamics at the tripartite synapse include presynaptic and postsynaptic components and are tightly regulated by neuron-astrocyte crosstalk. Here, we delineate the role of glutamate homeostasis at the tripartite synapse in schizophrenia-related cognitive dysfunction. We focus on cognitive domains that can be readily measured in humans and rodents, i.e., working memory, recognition memory, cognitive flexibility, and response inhibition. We describe tasks used to measure cognitive function in these domains in humans and rodents, and the relevance of glutamate alterations in these domains. Next, we delve into glutamate tripartite synaptic components and summarize findings that implicate the relevance of these components to specific cognitive domains. These collective findings indicate that neuron-astrocyte crosstalk at the tripartite synapse is essential for cognition, and that pre- and postsynaptic components play a critical role in maintaining glutamate homeostasis and cognitive well-being. The contribution of these components to cognitive function should be considered in order to better understand the role played by glutamate signaling in cognition and develop efficient pharmacological treatment avenues for schizophrenia treatment-resistant symptoms.
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Affiliation(s)
- Hagar Bauminger
- School of Psychological Sciences, Department of Psychology, University of Haifa, Haifa 3498838, Israel;
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa 3498838, Israel
| | - Inna Gaisler-Salomon
- School of Psychological Sciences, Department of Psychology, University of Haifa, Haifa 3498838, Israel;
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa 3498838, Israel
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Luessen DJ, Conn PJ. Allosteric Modulators of Metabotropic Glutamate Receptors as Novel Therapeutics for Neuropsychiatric Disease. Pharmacol Rev 2022; 74:630-661. [PMID: 35710132 PMCID: PMC9553119 DOI: 10.1124/pharmrev.121.000540] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors, a family of G-protein-coupled receptors, have been identified as novel therapeutic targets based on extensive research supporting their diverse contributions to cell signaling and physiology throughout the nervous system and important roles in regulating complex behaviors, such as cognition, reward, and movement. Thus, targeting mGlu receptors may be a promising strategy for the treatment of several brain disorders. Ongoing advances in the discovery of subtype-selective allosteric modulators for mGlu receptors has provided an unprecedented opportunity for highly specific modulation of signaling by individual mGlu receptor subtypes in the brain by targeting sites distinct from orthosteric or endogenous ligand binding sites on mGlu receptors. These pharmacological agents provide the unparalleled opportunity to selectively regulate neuronal excitability, synaptic transmission, and subsequent behavioral output pertinent to many brain disorders. Here, we review preclinical and clinical evidence supporting the utility of mGlu receptor allosteric modulators as novel therapeutic approaches to treat neuropsychiatric diseases, such as schizophrenia, substance use disorders, and stress-related disorders.
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7
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Dogra S, Conn PJ. Metabotropic glutamate receptors as emerging targets for the treatment of schizophrenia. Mol Pharmacol 2022; 101:275-285. [PMID: 35246479 PMCID: PMC9092465 DOI: 10.1124/molpharm.121.000460] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/22/2022] [Indexed: 11/22/2022] Open
Abstract
Accumulating evidence of glutamatergic abnormalities in the brains of schizophrenia patients has led to efforts to target various components of glutamatergic signaling as potential new approaches for schizophrenia. Exciting research suggests that metabotropic glutamate (mGlu) receptors could provide a fundamentally new approach for better symptomatic relief in schizophrenia patients. In preclinical studies, the mGlu5 receptor positive allosteric modulators (PAMs) have efficacy in animal models relevant for all symptom domains in schizophrenia. Interestingly, biased pure mGlu5 receptor PAMs that do not potentiate coupling of mGlu5 receptors to NMDA receptors lack neurotoxic effects associated with mGlu5 PAMs that enhance coupling to N-methyl-D-aspartate (NMDA) receptors or have allosteric agonist activity (ago-PAMs). This provides a better therapeutic profile for treating schizophrenia-like symptoms. Additionally, the mGlu1 receptor PAMs modulate dopamine release in the striatum, which may contribute to their antipsychotic-like effects. Besides group I mGlu (mGlu1 and mGlu5) receptors, agonists of mGlu2/3 receptor also induce robust antipsychotic-like and pro-cognitive effects in rodents and may be effective in treating symptoms of schizophrenia in a selective group of patients. Additionally, mGlu2/4 receptor heterodimers modulate glutamatergic neurotransmission in the prefrontal cortex at selective synapses activated in schizophrenia and, therefore, hold potential as novel antipsychotics. Excitingly, the mGlu3 receptor activation can enhance cognition in rodents suggesting that mGlu3 receptor agonist/PAM could provide a novel approach for the treatment of cognitive deficits in schizophrenia. Collectively, the development of mGlu receptor-specific ligands may provide an alternative approach to meet the clinical need for safer and efficacious therapeutics for schizophrenia. Significance Statement The currently available antipsychotic medications do not show significant efficacy for treating negative symptoms and cognitive deficits in schizophrenia. Emerging preclinical and clinical literature suggests that pharmacological targeting of metabotropic glutamate receptors could potentially provide an alternative approach for designing safer and efficacious therapeutics for treating schizophrenia.
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Miller-Rhodes P, Piazza N, Mattle A, Teboul E, Ehmann M, Morris-Schaffer K, Markowski VP. Sex-specific behavioral impairments produced by neonatal exposure to MK-801 are partially reversed by adolescent CDPPB treatment. Neurotoxicol Teratol 2022; 89:107053. [PMID: 34826568 DOI: 10.1016/j.ntt.2021.107053] [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: 07/08/2021] [Revised: 11/18/2021] [Accepted: 11/18/2021] [Indexed: 11/25/2022]
Abstract
Psychomimetic behaviors manifest in adult rodents long after neonatal exposure to the noncompetitive NMDA receptor antagonist MK-801. In the present study, we used this neurodevelopmental model of schizophrenia to evaluate the therapeutic potential of positive allosteric modulation of metabotropic glutamate receptor 5 (mGluR5) during adolescence. To this end, we randomly assigned male and female C57BL6 mouse littermates to one of three treatment groups: (i) neonatal and adolescent saline, (ii) neonatal MK-801 (0.25 mg/kg) and adolescent saline, and (iii) neonatal MK-801 and adolescent CDPPB (10 mg/kg), a positive allosteric modulator of mGluR5. When animals reached adulthood, a wide range of behavioral tests were conducted including sucrose preference, anxiety assessment in the elevated plus maze, and a series of food-reinforced operant procedures meant to assess motor activity, motivation, learning, and attention. Neonatal MK-801 exposure produced profound motor hyperactivity in both sexes and attenuated sucrose preference in males, effects that were reversed by CDPPB. MK-801 produced other deficits such as impaired set shifting or response inhibition deficits that were not reversed by CDPPB. Overall, female mice were more susceptible to MK-801's behavioral effects than males. These findings further support the use of neonatal MK-801 exposure as an animal model of schizophrenia and suggest that CDPPB can reverse the neurodevelopmental progression of some schizophrenia-like behaviors.
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Affiliation(s)
- Patrick Miller-Rhodes
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America
| | - Nadine Piazza
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America
| | - Anna Mattle
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America
| | - Eric Teboul
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America
| | - Megan Ehmann
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America
| | - Keith Morris-Schaffer
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America
| | - Vincent P Markowski
- Department of Psychology, State University of New York at Geneseo, Geneseo, NY 14454, United States of America.
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Yang F, Zhao YJ, Chen SJ, Li YR, Yang PY, Qi JY, Wang XS, Wang M, Li XB, Feng B, Wu YM, Liu SB, Zhang K. Disrupting Cannabinoid Receptor Interacting Protein 1 Rescues Cognitive Flexibility in Long-Term Estrogen-Deprived Female Mice. Brain Res Bull 2022; 181:77-86. [DOI: 10.1016/j.brainresbull.2022.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/11/2022] [Accepted: 01/22/2022] [Indexed: 11/02/2022]
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10
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Dogra S, Stansley BJ, Xiang Z, Qian W, Gogliotti RG, Nicoletti F, Lindsley CW, Niswender CM, Joffe ME, Conn PJ. Activating mGlu 3 Metabotropic Glutamate Receptors Rescues Schizophrenia-like Cognitive Deficits Through Metaplastic Adaptations Within the Hippocampus. Biol Psychiatry 2021; 90:385-398. [PMID: 33965197 PMCID: PMC8403106 DOI: 10.1016/j.biopsych.2021.02.970] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND Polymorphisms in GRM3, the gene encoding the mGlu3 metabotropic glutamate receptor, are associated with impaired cognition and neuropsychiatric disorders such as schizophrenia. Limited availability of selective genetic and molecular tools has hindered progress in developing a clear understanding of the mechanisms through which mGlu3 receptors regulate synaptic plasticity and cognition. METHODS We examined associative learning in mice with trace fear conditioning, a hippocampal-dependent learning task disrupted in patients with schizophrenia. Underlying cellular mechanisms were assessed using ex vivo hippocampal slice preparations with selective pharmacological tools and selective genetic deletion of mGlu3 receptor expression in specific neuronal subpopulations. RESULTS mGlu3 receptor activation enhanced trace fear conditioning and reversed deficits induced by subchronic phencyclidine. Mechanistic studies revealed that mGlu3 receptor activation induced metaplastic changes, biasing afferent stimulation to induce long-term potentiation through an mGlu5 receptor-dependent, endocannabinoid-mediated, disinhibitory mechanism. Selective genetic deletion of either mGlu3 or mGlu5 from hippocampal pyramidal cells eliminated effects of mGlu3 activation, revealing a novel mechanism by which mGlu3 and mGlu5 interact to enhance cognitive function. CONCLUSIONS These data demonstrate that activation of mGlu3 receptors in hippocampal pyramidal cells enhances hippocampal-dependent cognition in control and impaired mice by inducing a novel form of metaplasticity to regulate circuit function, providing a clear mechanism through which genetic variation in GRM3 can contribute to cognitive deficits. Developing approaches to positively modulate mGlu3 receptor function represents an encouraging new avenue for treating cognitive disruption in schizophrenia and other psychiatric diseases.
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Affiliation(s)
- Shalini Dogra
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Branden J. Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Zixiu Xiang
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Weilun Qian
- Vanderbilt University, Nashville, TN 37232, USA
| | - Rocco G. Gogliotti
- Molecular Pharmacology and Neuroscience Department, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, University Sapienza of Roma, Roma, Italy
| | - Craig W. Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Colleen M. Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Max E. Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Correspondence to: Max E. Joffe, Ph.D., Research Instructor, Department of Pharmacology, Vanderbilt University, 12475E MRB4, Nashville, TN 37232-0697, Tel. (615) 322-6730, Fax. (615) 343-3088, , Twitter: @mejoffe; P. Jeffrey Conn, Ph.D., Lee E. Limbird Professor of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, 1205 Light Hall, Nashville, TN 37232-0697, Tel. (615) 936-2478, Fax. (615) 343-3088,
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA,Correspondence to: Max E. Joffe, Ph.D., Research Instructor, Department of Pharmacology, Vanderbilt University, 12475E MRB4, Nashville, TN 37232-0697, Tel. (615) 322-6730, Fax. (615) 343-3088, , Twitter: @mejoffe; P. Jeffrey Conn, Ph.D., Lee E. Limbird Professor of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, 1205 Light Hall, Nashville, TN 37232-0697, Tel. (615) 936-2478, Fax. (615) 343-3088,
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McQuail JA, Beas BS, Kelly KB, Hernandez CM, Bizon JL, Frazier CJ. Attenuated NMDAR signaling on fast-spiking interneurons in prefrontal cortex contributes to age-related decline of cognitive flexibility. Neuropharmacology 2021; 197:108720. [PMID: 34273386 DOI: 10.1016/j.neuropharm.2021.108720] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 02/01/2023]
Abstract
Ionotropic glutamate receptors of the NMDA and AMPA subtypes transduce excitatory signaling on neurons in the prefrontal cortex (PFC) in support of cognitive flexibility. Cognitive flexibility is reliably observed to decline at advanced ages, coinciding with changes in PFC glutamate receptor expression and neuronal physiology. However, the relationship between age-related impairment of cognitive flexibility and changes to excitatory signaling on distinct classes of PFC neurons is not known. In this study, one cohort of young adult (4 months) and aged (20 months) male F344 rats were characterized for cognitive flexibility on an operant set-shifting task. Expression of the essential NMDAR subunit, NR1, was correlated with individual differences in set-shifting abilities such that lower NR1 in the aged PFC was associated with worse set-shifting. In contrast, lower expression of two AMPAR subunits, GluR1 and GluR2, was not associated with set-shift abilities in aging. As NMDARs are expressed by both pyramidal cells and fast-spiking interneurons (FSI) in PFC, whole-cell patch clamp recordings were performed in a second cohort of age-matched rats to compare age-associated changes on these neuronal subtypes. Evoked excitatory postsynaptic currents were generated using a bipolar stimulator while AMPAR vs. NMDAR-mediated components were isolated using pharmacological tools. The results revealed a clear increase in AMPA/NMDA ratio in FSIs that was not present in pyramidal neurons. Together, these data indicate that loss of NMDARs on interneurons in PFC contributes to age-related impairment of cognitive flexibility.
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Affiliation(s)
- Joseph A McQuail
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, USA.
| | - B Sofia Beas
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA; Unit on the Neurobiology of Affective Memory, National Institute of Mental Health, Bethesda, MD, 20892, USA
| | - Kyle B Kelly
- Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL, 32610, USA
| | - Caesar M Hernandez
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA; Department of Cellular, Development, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jennifer L Bizon
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Charles J Frazier
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA; Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL, 32610, USA.
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12
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Wang X, Ali N, Lin CLG. Emerging role of glutamate in the pathophysiology and therapeutics of Gulf War illness. Life Sci 2021; 280:119609. [PMID: 33991547 DOI: 10.1016/j.lfs.2021.119609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 11/20/2022]
Abstract
Gulf War illness (GWI) is a chronic and multi-symptomatic disorder affecting veterans who served in the Gulf War. The commonly reported symptoms in GWI veterans include mood problems, cognitive impairment, muscle and joint pain, migraine/headache, chronic fatigue, gastrointestinal complaints, skin rashes, and respiratory problems. Neuroimaging studies have revealed significant brain structure alterations in GWI veterans, including subcortical atrophy, decreased volume of the hippocampus, reduced total grey and white matter, and increased brain white matter axial diffusivity. These brain changes may contribute to or increase the severities of the GWI-related symptoms. Epidemiological studies have revealed that neurotoxic exposures and stress may be significant contributors to the development of GWI. However, the mechanism underlying how the exposure and stress could contribute to the multi-symptomatic disorder of GWI remains unclear. We and others have demonstrated that rodent models exposed to GW-related agents and stress exhibited higher extracellular glutamate levels, as well as impaired structure and function of glutamatergic synapses. Restoration of the glutamatergic synapses ameliorated the GWI-related pathological and behavioral deficits. Moreover, recent studies showed that a low-glutamate diet reduced multiple symptoms in GWI veterans, suggesting an important role of the glutamatergic system in GWI. Currently, growing evidence has indicated that abnormal glutamate neurotransmission may contribute to the GWI symptoms. This review summarizes the potential roles of glutamate dyshomeostasis and dysfunction of the glutamatergic system in linking the initial cause to the multi-symptomatic outcomes in GWI and suggests the glutamatergic system as a therapeutic target for GWI.
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Affiliation(s)
- Xueqin Wang
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Noor Ali
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Chien-Liang Glenn Lin
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, USA.
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Kryszkowski W, Boczek T. The G Protein-Coupled Glutamate Receptors as Novel Molecular Targets in Schizophrenia Treatment-A Narrative Review. J Clin Med 2021; 10:jcm10071475. [PMID: 33918323 PMCID: PMC8038150 DOI: 10.3390/jcm10071475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/24/2021] [Accepted: 03/28/2021] [Indexed: 12/02/2022] Open
Abstract
Schizophrenia is a severe neuropsychiatric disease with an unknown etiology. The research into the neurobiology of this disease led to several models aimed at explaining the link between perturbations in brain function and the manifestation of psychotic symptoms. The glutamatergic hypothesis postulates that disrupted glutamate neurotransmission may mediate cognitive and psychosocial impairments by affecting the connections between the cortex and the thalamus. In this regard, the greatest attention has been given to ionotropic NMDA receptor hypofunction. However, converging data indicates metabotropic glutamate receptors as crucial for cognitive and psychomotor function. The distribution of these receptors in the brain regions related to schizophrenia and their regulatory role in glutamate release make them promising molecular targets for novel antipsychotics. This article reviews the progress in the research on the role of metabotropic glutamate receptors in schizophrenia etiopathology.
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Affiliation(s)
- Waldemar Kryszkowski
- General Psychiatric Ward, Babinski Memorial Hospital in Lodz, 91229 Lodz, Poland;
| | - Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University of Lodz, 92215 Lodz, Poland
- Correspondence:
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Effects of the Positive Allosteric Modulator of Metabotropic Glutamate Receptor 5, VU-29, on Maintenance Association between Environmental Cues and Rewarding Properties of Ethanol in Rats. Biomolecules 2020; 10:biom10050793. [PMID: 32443872 PMCID: PMC7277181 DOI: 10.3390/biom10050793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 12/28/2022] Open
Abstract
: Metabotropic glutamate subtype 5 (mGlu5) receptors are implicated in various forms of synaptic plasticity, including drugs of abuse. In drug-addicted individuals, associative memories can drive relapse to drug use. The present study investigated the potential of the mGlu5 receptor positive allosteric modulator (PAM), VU-29 (30 mg/kg, i.p.), to inhibit the maintenance of a learned association between ethanol and environmental context by using conditioned place preference (CPP) in rats. The ethanol-CPP was established by the administration of ethanol (1.0 g/kg, i.p. × 10 days) using an unbiased procedure. Following ethanol conditioning, VU-29 was administered at various post-conditioning times (ethanol free state at the home cage) to ascertain if there was a temporal window during which VU-29 would be effective. Our experiments indicated that VU-29 did not affect the expression of ethanol-induced CPP when it was given over two post-conditioning days. However, the expression of ethanol-CPP was inhibited by 10-day home cage administration of VU-29, but not by first 2-day or last 2-day injection of VU-29 during the 10-day period. These findings reveal that VU-29 can inhibit the maintenance of ethanol-induced CPP, and that treatment duration contributes to this effect of VU-29. Furthermore, VU-29 effect was reversed by pretreatment with either MTEP (the mGlu5 receptor antagonist), or MK-801 (the N-methyl-D-aspartate-NMDA receptor antagonist). Thus, the inhibitory effect of VU-29 is dependent on the functional interaction between mGlu5 and NMDA receptors. Because a reduction in ethanol-associated cues can reduce relapse, mGlu5 receptor PAM would be useful for therapy of alcoholism. Future research is required to confirm the current findings.
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Cole RD, Zimmerman M, Matchanova A, Kutlu MG, Gould TJ, Parikh V. Cognitive rigidity and BDNF-mediated frontostriatal glutamate neuroadaptations during spontaneous nicotine withdrawal. Neuropsychopharmacology 2020; 45:866-876. [PMID: 31752015 PMCID: PMC7075915 DOI: 10.1038/s41386-019-0574-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 10/13/2019] [Accepted: 11/14/2019] [Indexed: 01/12/2023]
Abstract
Cognitive flexibility is the ability to switch strategic responses adaptively in changing environments. Cognitive rigidity imposed by neural circuit adaptations during nicotine abstinence may foster maladaptive nicotine taking in addicts. We systematically examined the effects of spontaneous withdrawal in mice exposed to either nicotine (6.3 or 18 mg/kg/day) or saline for 14 days on cognitive flexibility using an operant strategy set-shifting task. Because frontostriatal circuits are critical for cognitive flexibility and brain-derived neurotrophic factor (BDNF) modulates glutamate plasticity in these circuits, we also explored the effects of nicotine withdrawal on these neurochemical substrates. Mice undergoing nicotine withdrawal required more trials to attain strategy-switching criterion. Error analysis show that animals withdrawn from both nicotine doses committed higher perseverative errors, which correlated with measures of anxiety. However, animals treated with the higher nicotine dose also displayed more strategy maintenance errors that remained independent of negative affect. BDNF mRNA expression increased in the medial prefrontal cortex (mPFC) following nicotine withdrawal. Surprisingly, BDNF protein declined in mPFC but was elevated in dorsal striatum (DS). DS BDNF protein positively correlated with perseverative and maintenance errors, suggesting mPFC-DS overflow of BDNF during withdrawal. BDNF-evoked glutamate release and synapsin phosphorylation was attenuated within DS synapses, but enhanced in the nucleus accumbens, suggesting a dichotomous role of BDNF signaling in striatal regions. Taken together, these data suggest that spontaneous nicotine withdrawal impairs distinct components of cognitive set-shifting and these deficits may be linked to BDNF-mediated alterations in glutamate signaling dynamics in discrete frontostriatal circuits.
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Affiliation(s)
- Robert D. Cole
- 0000 0001 2248 3398grid.264727.2Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122 USA
| | - Matty Zimmerman
- 0000 0001 2248 3398grid.264727.2Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122 USA
| | - Anastasia Matchanova
- 0000 0001 2248 3398grid.264727.2Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122 USA
| | - Munir Gunes Kutlu
- 0000 0001 2097 4281grid.29857.31Department of Biobehavioral Health, Pennsylvania State University, University Park, PA 16802 USA
| | - Thomas J. Gould
- 0000 0001 2097 4281grid.29857.31Department of Biobehavioral Health, Pennsylvania State University, University Park, PA 16802 USA
| | - Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, 19122, USA.
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Gobin C, Schwendt M. The cognitive cost of reducing relapse to cocaine-seeking with mGlu5 allosteric modulators. Psychopharmacology (Berl) 2020; 237:115-125. [PMID: 31446451 DOI: 10.1007/s00213-019-05351-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 08/09/2019] [Indexed: 12/24/2022]
Abstract
RATIONALE Cocaine use disorder (CUD) remains difficult to treat with no FDA-approved medications to reduce relapse. Antagonism of metabotropic glutamate receptor 5 (mGlu5) has been demonstrated to decrease cocaine-seeking but may also further compromise cognitive function in long-term cocaine users. OBJECTIVES Here we assessed the effect of repeated administration of negative or positive allosteric modulators (NAM or PAM) of mGlu5 on both cognitive performance and (context+cue)-primed cocaine-seeking after prolonged abstinence (≥ 45 days). METHODS Adult male Sprague-Dawley rats underwent 6 days of short-access (1 h/day) and 12 days of long-access (6 h/day) cocaine self-administration. Rats were then trained and tested in a delayed match-to-sample (DMS) task to establish baseline working memory performance over a 5-day block of testing. Next, rats received daily systemic administration of the mGlu5 NAM 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP; 3 mg/kg), the mGlu5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB; 30 mg/kg) or vehicle prior to DMS testing during a block of 5 days, followed by a 5-day washout DMS testing block. RESULTS MTEP and CDPPB decreased drug-seeking in response to cocaine-associated cues after prolonged abstinence. However, repeated treatment with MTEP impaired working memory, while CDPPB had no effects on performance. CONCLUSIONS These results emphasize the relevance of evaluating cognitive function within the context of investigating pharmacotherapies to treat CUD. Further research is needed to determine how two mechanistically different pharmacological compounds can exert the same behavioral effects to reduce cocaine-seeking.
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Affiliation(s)
- Christina Gobin
- Psychology Department, University of Florida, 114 Psychology Building, 945 Center Drive, Gainesville, FL, 32611-2250, USA
- Center for Addiction Research and Education (CARE), University of Florida, Gainesville, FL, USA
| | - Marek Schwendt
- Psychology Department, University of Florida, 114 Psychology Building, 945 Center Drive, Gainesville, FL, 32611-2250, USA.
- Center for Addiction Research and Education (CARE), University of Florida, Gainesville, FL, USA.
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Xiang Z, Lv X, Maksymetz J, Stansley BJ, Ghoshal A, Gogliotti RG, Niswender CM, Lindsley CW, Conn PJ. mGlu 5 Positive Allosteric Modulators Facilitate Long-Term Potentiation via Disinhibition Mediated by mGlu 5-Endocannabinoid Signaling. ACS Pharmacol Transl Sci 2019; 2:198-209. [PMID: 31259318 PMCID: PMC6591772 DOI: 10.1021/acsptsci.9b00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 11/29/2022]
Abstract
Metabotropic glutamate (mGlu) receptor type 5 (mGlu5) positive allosteric modulators (PAMs) enhance hippocampal long-term potentiation (LTP) and have cognition-enhancing effects in animal models. These effects were initially thought to be mediated by potentiation of mGlu5 modulation of N-methyl-d-aspartate receptor (NMDAR) currents. However, a biased mGlu5 PAM that potentiates Gαq-dependent mGlu5 signaling, but not mGlu5 modulation of NMDAR currents, retains cognition-enhancing effects in animal models, suggesting that potentiation of NMDAR currents is not required for these in vivo effects of mGlu5 PAMs. However, it is not clear whether the potentiation of NMDAR currents is critical for the ability of mGlu5 PAMs to enhance hippocampal LTP. We now report the characterization of effects of two structurally distinct mGlu5 PAMs, VU-29 and VU0092273, on NMDAR currents and hippocampal LTP. As with other mGlu5 PAMs that do not display observable bias for potentiation of NMDAR currents, VU0092273 enhanced both mGlu5 modulation of NMDAR currents and induction of LTP at the hippocampal Schaffer collateral (SC)-CA1 synapse. In contrast, VU-29 did not potentiate mGlu5 modulation of NMDAR currents but induced robust potentiation of hippocampal LTP. Interestingly, both VU-29 and VU0092273 suppressed evoked inhibitory postsynaptic currents (eIPSCs) in CA1 pyramidal cells, and this effect was blocked by the cannabinoid receptor type 1 (CB1) antagonist AM251. Furthermore, AM251 blocked the ability of both mGlu5 PAMs to enhance LTP. Finally, both PAMs failed to enhance LTP in mice with the restricted genetic deletion of mGlu5 in CA1 pyramidal cells. Taken together with previous findings, these results suggest that enhancement of LTP by mGlu5 PAMs does not depend on mGlu5 modulation of NMDAR currents but is mediated by a previously established mechanism in which mGlu5 in CA1 pyramidal cells induces endocannabinoid release and CB1-dependent disinhibition.
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Affiliation(s)
- Zixiu Xiang
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Xiaohui Lv
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - James Maksymetz
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Branden J Stansley
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Ayan Ghoshal
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Rocco G Gogliotti
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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18
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Cholinergic Neurons of the Medial Septum Are Crucial for Sensorimotor Gating. J Neurosci 2019; 39:5234-5242. [PMID: 31028115 DOI: 10.1523/jneurosci.0950-18.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 03/23/2019] [Accepted: 04/15/2019] [Indexed: 12/11/2022] Open
Abstract
Hypofunction of NMDA receptors has been considered a possible cause for the pathophysiology of schizophrenia. More recently, indirect ways to regulate NMDA that would be less disruptive have been proposed and metabotropic glutamate receptor subtype 5 (mGluR5) represents one such candidate. To characterize the cell populations involved, we demonstrated here that knock-out (KO) of mGluR5 in cholinergic, but not glutamatergic or parvalbumin (PV)-positive GABAergic, neurons reduced prepulse inhibition of the startle response (PPI) and enhanced sensitivity to MK801-induced locomotor activity. Inhibition of cholinergic neurons in the medial septum by DREADD (designer receptors exclusively activated by designer drugs) resulted in reduced PPI further demonstrating the importance of these neurons in sensorimotor gating. Volume imaging and quantification were used to compare PV and cholinergic cell distribution, density, and total cell counts in the different cell-type-specific KO lines. Electrophysiological studies showed reduced NMDA receptor-mediated currents in cholinergic neurons of the medial septum in mGluR5 KO mice. These results obtained from male and female mice indicate that cholinergic neurons in the medial septum represent a key cell type involved in sensorimotor gating and are relevant to pathologies associated with disrupted sensorimotor gating such as schizophrenia.SIGNIFICANCE STATEMENT The mechanistic complexity underlying psychiatric disorders remains a major challenge that is hindering the drug discovery process. Here, we generated genetically modified mouse lines to better characterize the involvement of the receptor mGluR5 in the fine-tuning of NMDA receptors, specifically in the context of sensorimotor gating. We evaluated the importance of knocking-out mGluR5 in three different cell types in two brain regions and performed different sets of experiments including behavioral testing and electrophysiological recordings. We demonstrated that cholinergic neurons in the medial septum represent a key cell-type involved in sensorimotor gating. We are proposing that pathologies associated with disrupted sensorimotor gating, such as with schizophrenia, could benefit from further evaluating strategies to modulate specifically cholinergic neurons in the medial septum.
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Mechanisms underlying prelimbic prefrontal cortex mGlu 3/mGlu 5-dependent plasticity and reversal learning deficits following acute stress. Neuropharmacology 2018; 144:19-28. [PMID: 30326237 DOI: 10.1016/j.neuropharm.2018.10.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/22/2018] [Accepted: 10/12/2018] [Indexed: 01/09/2023]
Abstract
Stress can precipitate or worsen symptoms of many psychiatric illnesses. Dysregulation of the prefrontal cortex (PFC) glutamate system may underlie these disruptions and restoring PFC glutamate signaling has emerged as a promising avenue for the treatment of stress disorders. Recently, we demonstrated that activation of metabotropic glutamate receptor subtype 3 (mGlu3) induces a postsynaptic form of long-term depression (LTD) that is dependent on the activity of another subtype, mGlu5. Stress exposure disrupted this plasticity, but the underlying signaling mechanisms and involvement in higher-order cognition have not yet been investigated. Acute stress was applied by 20-min restraint and early reversal learning was evaluated in an operant-based food-seeking task. We employed whole-cell patch-clamp recordings of layer 5 prelimbic (PL)-PFC pyramidal cells to examine mGlu3-LTD and several mechanistically distinct mGlu5-dependent functions. Acute stress impaired both mGlu3-LTD and early reversal learning. Interestingly, potentiating mGlu5 signaling with the mGlu5 positive allosteric modulator (PAM) VU0409551 rescued stress-induced deficits in both mGlu3-LTD and reversal learning. Other aspects of PL-PFC mGlu5 function were not disrupted following stress; however, signaling downstream of mGlu5-Homer interactions, phosphoinositide-3-kinase (PI3K), Akt, and glycogen synthase kinase 3β was implicated in these phenomena. These findings demonstrate that acute stress disrupts early reversal learning and PL-PFC-dependent synaptic plasticity and that potentiating mGlu5 function can restore these impairments. These findings provide a framework through which modulating coordinated mGlu3/mGlu5 signaling may confer benefits for the treatment of stress-related psychiatric disorders.
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20
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Lum JS, Millard SJ, Frank E, Matosin N, Huang XF, Ooi L, Newell KA. Chronic Adolescent CDPPB Treatment Alters Short-Term, but not Long-Term, Glutamatergic Receptor Expression. Neurochem Res 2018; 43:1683-1691. [PMID: 29936568 DOI: 10.1007/s11064-018-2584-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/30/2018] [Accepted: 06/20/2018] [Indexed: 12/21/2022]
Abstract
Dysfunction of the glutamatergic system is believed to underlie many neurodevelopmental disorders including autism, Rett syndrome and schizophrenia. Metabotropic glutamate receptor (mGluR5) positive allosteric modulators (PAM) potentiate glutamatergic signaling, particularly indirectly via the NMDA receptor. Preclinical studies report mGluR5 PAMs can improve schizophrenia-relevant behaviours. Furthermore, adolescent administration has shown to prevent cognitive induced deficits in adult rodents. However, there is limited understanding of the short- and long-term neurochemical effects of mGluR5 PAMs, which may underlie their therapeutic effects. We examined the effect of 7-day adolescent (PN28-34) treatment with the mGluR5 PAM, CDDPB (30 mg/kg), on glutamatergic receptor expression at adolescence (PN35) and adulthood (PN96). Immunoblot analysis revealed that 7-day adolescent CDPPB treatment increased protein expression of glutamatergic receptors including the NMDA receptor subunits, NR1 and NR2A and the AMPA subunits (GluA1 and GluA2) in the adolescent hippocampus, changes that did not extend to adulthood. In contrast, there were no changes in the adolescent frontal cortex, however elevated mGluR5 protein expression was observed at adulthood following adolescent CDPPB treatment. The present study indicates adolescent CDPPB treatment may cause brain region dependent effects on the glutamatergic system, which do not persist into adulthood. These findings may have implications for the preclinical development of mGluR5 PAMs for the treatment of neurodevelopmental disorders.
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Affiliation(s)
- Jeremy S Lum
- School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
- Schizophrenia Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia.
| | - Samuel J Millard
- School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Elisabeth Frank
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
- Schizophrenia Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
| | - Natalie Matosin
- School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
- Schizophrenia Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
| | - Xu-Feng Huang
- School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
- School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Kelly A Newell
- School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
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Gupta I, Young AMJ. Metabotropic glutamate receptor modulation of dopamine release in the nucleus accumbens shell is unaffected by phencyclidine pretreatment: In vitro assessment using fast-scan cyclic voltammetry rat brain slices. Brain Res 2018. [PMID: 29524437 DOI: 10.1016/j.brainres.2018.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The non-competitive glutamate antagonist, phencyclidine is used in rodents to model behavioural deficits see in schizophrenia. Importantly, these deficits endure long after the cessation of short-term chronic treatment (sub-chronic), indicating that the drug treatment causes long-term changes in the physiology and/or chemistry of the brain. There is evidence that this may occur through glutamatergic modulation of mesolimbic dopamine release, perhaps involving metabotropic glutamate receptors (mGluR). This study sought to investigate the effect of sub-chronic phencyclidine pretreatment on modulation of dopamine neurotransmission by metabotropic glutamate receptors 2 and 5 (mGluR2 and mGluR5) in the nucleus accumbens shell in vitro, with the hypothesis that phencyclidine pretreatment would disrupt the mGluR-mediated modulation of dopamine release. We showed that the orthosteric mGluR2 agonist LY379268 (0.1 µM, 1 µM and 10 µM) and mGluR5 positive allosteric modulator CDPPB (1 µM and 10 µM) both attenuated potassium-evoked dopamine release, underscoring their role in modulating dopamine neurotransmission in the nucleus accumbens. Sub-chronic PCP treatment, which caused cognitive deficits measured by performance in the novel object recognition task, modelling aspects of behavioral deficits seen in schizophrenia, induced neurobiological changes that enhanced dopamine release in the nucleus accumbens, but had no effect on mGluR2 or mGluR5 mediated changes in dopamine release. Therefore it is unlikely that schizophrenia-related behavioural changes seen after sub-chronic phencyclidine pre-treatment are mediated through mGluR modulation of dopamine release.
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Affiliation(s)
- Ishan Gupta
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Andrew M J Young
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK.
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22
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Pehrson AL, Pedersen CS, Tølbøl KS, Sanchez C. Vortioxetine Treatment Reverses Subchronic PCP Treatment-Induced Cognitive Impairments: A Potential Role for Serotonin Receptor-Mediated Regulation of GABA Neurotransmission. Front Pharmacol 2018; 9:162. [PMID: 29559911 PMCID: PMC5845537 DOI: 10.3389/fphar.2018.00162] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/14/2018] [Indexed: 01/21/2023] Open
Abstract
Major depressive disorder (MDD) is associated with cognitive impairments that may contribute to poor functional outcomes. Clinical data suggests that the multimodal antidepressant vortioxetine attenuates some cognitive impairments in MDD patients, but the mechanistic basis for these improvements is unclear. One theory suggests that vortioxetine improves cognition by suppressing γ-amino butyric acid (GABA)ergic neurotransmission, thereby increasing glutamatergic activation. Vortioxetine’s effects on cognition, GABA and glutamate neurotransmission have been supported in separate experiments, but no empirical work has directly connected vortioxetine’s cognitive effects to those on GABA and glutamate neurotransmission. In this paper, we attempt to bridge this gap by evaluating vortioxetine’s effects in the subchronic PCP (subPCP) model, which induces impaired cognitive function and altered GABA and glutamate neurotransmission. We demonstrate that acute or subchronic vortioxetine treatment attenuated subPCP-induced deficits in attentional set shifting (AST) performance, and that the selective 5-HT3 receptor antagonist ondansetron or the 5-HT reuptake inhibitor escitalopram could mimic this effect. Furthermore, acute vortioxetine treatment reversed subPCP-induced object recognition (OR) deficits in rats, while subchronic vortioxetine reversed subPCP-induced Object Recognition and object placement impairments in mice. Finally, subPCP treatment reduced GABAB receptor expression in a manner that was insensitive to vortioxetine treatment, and subchronic vortioxetine treatment alone, but not in combination with subPCP, significantly increased GABA’s affinity for the GABAA receptor. These data suggest that vortioxetine reverses cognitive impairments in a model associated with altered GABA and glutamate neurotransmission, further supporting the hypothesis that vortioxetine’s GABAergic and glutamatergic effects are relevant for cognitive function.
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Affiliation(s)
- Alan L Pehrson
- Department of Psychology, Montclair State University, Montclair, NJ, United States
| | | | | | - Connie Sanchez
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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23
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Isherwood SN, Robbins TW, Dalley JW, Pekcec A. Bidirectional variation in glutamate efflux in the medial prefrontal cortex induced by selective positive and negative allosteric mGluR5 modulators. J Neurochem 2018; 145:111-124. [PMID: 29315577 PMCID: PMC5972455 DOI: 10.1111/jnc.14290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/18/2017] [Accepted: 12/27/2017] [Indexed: 01/30/2023]
Abstract
Dysregulation of prefrontal cortical glutamatergic signalling via NMDA receptor hypofunction has been implicated in cognitive dysfunction and impaired inhibitory control in such neuropsychiatric disorders as schizophrenia, attention‐deficit hyperactivity disorder and drug addiction. Although NMDA receptors functionally interact with metabotropic glutamate receptor 5 (mGluR5), the consequence of this interaction for glutamate release in the prefrontal cortex (PFC) remains unknown. We therefore investigated the effects of positive and negative allosteric mGluR5 modulation on changes in extracellular glutamate efflux in the medial PFC (mPFC) induced by systemic administration of the non‐competitive NMDA receptor antagonist dizocilpine (or MK801) in rats. Extracellular glutamate efflux was measured following systemic administration of the positive allosteric mGluR5 modulator [S‐(4‐Fluoro‐phenyl)‐{3‐[3‐(4‐fluoro‐phenyl)‐[1,2,4]‐oxadiazol‐5‐yl]‐piperidin‐1‐yl}‐methanone] (ADX47273; 100 mg/kg, p.o.) and negative allosteric mGluR5 modulator [2‐chloro‐4‐{[1‐(4‐fluorophenyl)‐2,5‐dimethyl‐1H‐imidazol‐4‐yl]ethynyl}pyridine] (RO4917523; 0.3 mg/kg, p.o.), using a wireless glutamate biosensor in awake, freely moving rats. The effect of MK801 (0.03–0.06 mg/kg, s.c.) on mPFC glutamate efflux was also investigated in addition to the effects of MK801 (0.03 mg/kg, s.c.) following ADX47273 (100 mg/kg, p.o.) pre‐treatment. ADX47273 produced a sustained increase in glutamate efflux and increased the effect of NMDA receptor antagonism on glutamate efflux in the mPFC. In contrast, negative allosteric mGluR5 modulation with RO4917523 decreased glutamate efflux in the mPFC. These findings indicate that positive and negative allosteric mGluR5 modulators produce long lasting and opposing actions on extracellular glutamate efflux in the mPFC. Positive and negative allosteric modulators of mGluR5 may therefore be viable therapeutic agents to correct abnormalities in glutamatergic signalling present in a range of neuropsychiatric disorders. ![]()
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Affiliation(s)
- Sarah N Isherwood
- Boehringer Ingelheim Pharma GmbH & Co. KG, Div. Research Germany, Biberach an der Riss, Germany.,Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Trevor W Robbins
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.,Department of Psychology, University of Cambridge, Cambridge, UK
| | - Jeffrey W Dalley
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.,Department of Psychology, University of Cambridge, Cambridge, UK.,Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Anton Pekcec
- Boehringer Ingelheim Pharma GmbH & Co. KG, Div. Research Germany, Biberach an der Riss, Germany
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24
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Ghoshal A, Moran SP, Dickerson JW, Joffe ME, Grueter BA, Xiang Z, Lindsley CW, Rook JM, Conn PJ. Role of mGlu 5 Receptors and Inhibitory Neurotransmission in M 1 Dependent Muscarinic LTD in the Prefrontal Cortex: Implications in Schizophrenia. ACS Chem Neurosci 2017; 8:2254-2265. [PMID: 28679049 DOI: 10.1021/acschemneuro.7b00167] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Selective potentiation of the mGlu5 subtype of metabotropic glutamate (mGlu) receptor using positive allosteric modulators (PAMs) has robust cognition-enhancing effects in rodent models that are relevant for schizophrenia. Until recently, these effects were thought to be due to potentiation of mGlu5-induced modulation of NMDA receptor (NMDAR) currents and NMDAR-dependent synaptic plasticity. However, "biased" mGlu5 PAMs that do not potentiate mGlu5 effects on NMDAR currents show efficacy that is similar to that of prototypical mGlu5 PAMs, suggesting that NMDAR-independent mechanisms must be involved in these actions. We now report that synaptic activation of mGlu5 is required for a form of long-term depression (mLTD) in mouse prefrontal cortex (PFC) that is induced by activation of M1 muscarinic acetylcholine (mAChR) receptors, which was previously thought to be independent of mGlu5 activation. Interestingly, a biased mGlu5 PAM, VU0409551, that does not potentiate mGlu5 modulation of NMDAR currents, potentiated induction of mLTD. Furthermore, coactivation of mGlu5 and M1 receptors increased GABAA-dependent inhibitory tone in the PFC pyramidal neurons, which likely contributes to the observed mLTD. Finally, systemic administration of the biased mGlu5 PAM reversed deficits in mLTD and associated cognitive deficits in a model of cortical disruption caused by repeated phencyclidine exposure that is relevant for schizophrenia and was previously shown to be responsive to selective M1 muscarinic receptor PAMs. These studies provide exciting new insights into a novel mechanism by which mGlu5 PAMs can reverse deficits in PFC function and cognition that is independent of modulation of NMDAR currents.
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Affiliation(s)
- Ayan Ghoshal
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Sean P. Moran
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Jonathan W. Dickerson
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Max E. Joffe
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Brad A. Grueter
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Zixiu Xiang
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Craig W. Lindsley
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Jerri M. Rook
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - P. Jeffrey Conn
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
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25
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Mar AC, Nilsson SRO, Gamallo-Lana B, Lei M, Dourado T, Alsiö J, Saksida LM, Bussey TJ, Robbins TW. MAM-E17 rat model impairments on a novel continuous performance task: effects of potential cognitive enhancing drugs. Psychopharmacology (Berl) 2017; 234:2837-2857. [PMID: 28744563 PMCID: PMC5591806 DOI: 10.1007/s00213-017-4679-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/18/2017] [Indexed: 12/02/2022]
Abstract
RATIONALE Impairments in attention and inhibitory control are endophenotypic markers of neuropsychiatric disorders such as schizophrenia and represent key targets for therapeutic management. Robust preclinical models and assays sensitive to clinically relevant treatments are crucial for improving cognitive enhancement strategies. OBJECTIVES We assessed a rodent model with neural and behavioral features relevant to schizophrenia (gestational day 17 methylazoxymethanol acetate treatment (MAM-E17)) on a novel test of attention and executive function, and examined the impact of putative nootropic drugs. METHODS MAM-E17 and sham control rats were trained on a novel touchscreen-based rodent continuous performance test (rCPT) designed to closely mimic the human CPT paradigm. Performance following acute, systemic treatment with an array of pharmacological compounds was investigated. RESULTS Two cohorts of MAM-E17 rats were impaired on rCPT performance including deficits in sensitivity (d') and increased false alarm rates (FARs). Sulpiride (0-30 mg/kg) dose-dependently reduced elevated FAR in MAM-E17 rats whereas low-dose modafinil (8 mg/kg) only improved d' in sham controls. ABT-594 (5.9-19.4 μg/kg) and modafinil (64 mg/kg) showed expected stimulant-like effects, while LSN2463359 (5 mg/kg), RO493858 (10 mg/kg), atomoxetine (0.3-1 mg/kg), and sulpiride (30 mg/kg) showed expected suppressant effects on performance across all animals. Donepezil (0.1-1 mg/kg) showed near-significant enhancements in d', and EVP-6124 (0.3-3 mg/kg) exerted no effects in the rCPT paradigm. CONCLUSION The MAM-E17 model exhibits robust and replicable impairments in rCPT performance that resemble attention and inhibitory control deficits seen in schizophrenia. Pharmacological profiles were highly consistent with known drug effects on cognition in preclinical and clinical studies. The rCPT is a sensitive and reliable tool with high translational potential for understanding the etiology and treatment of disorders affecting attention and executive dysfunction.
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Affiliation(s)
- Adam C Mar
- Neuroscience Institute, New York University Medical Center, New York, NY, 10016, USA.
- Department of Neuroscience and Physiology, New York University Medical Center, New York, NY, USA.
- Department of Psychology, University of Cambridge, Cambridge, UK.
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.
| | - Simon R O Nilsson
- Neuroscience Institute, New York University Medical Center, New York, NY, 10016, USA
- Department of Neuroscience and Physiology, New York University Medical Center, New York, NY, USA
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Begoña Gamallo-Lana
- Neuroscience Institute, New York University Medical Center, New York, NY, 10016, USA
- Department of Neuroscience and Physiology, New York University Medical Center, New York, NY, USA
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Ming Lei
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Health Industry Management, Beijing International Studies University, 1 Dingfuzhuang Nanli, Beijing, China
| | - Theda Dourado
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Johan Alsiö
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Neuroscience, Unit of Functional Neurobiology, University of Uppsala, Uppsala, Sweden
| | - Lisa M Saksida
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, ON, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- The Brain and Mind Institute, Western University, London, ON, Canada
| | - Timothy J Bussey
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, ON, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- The Brain and Mind Institute, Western University, London, ON, Canada
| | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge, UK
- MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
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26
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Foster DJ, Conn PJ. Allosteric Modulation of GPCRs: New Insights and Potential Utility for Treatment of Schizophrenia and Other CNS Disorders. Neuron 2017; 94:431-446. [PMID: 28472649 PMCID: PMC5482176 DOI: 10.1016/j.neuron.2017.03.016] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/02/2017] [Accepted: 03/09/2017] [Indexed: 01/11/2023]
Abstract
G-protein-coupled receptors (GPCRs) play critical roles in regulating brain function. Recent advances have greatly expanded our understanding of these receptors as complex signaling machines that can adopt numerous conformations and modulate multiple downstream signaling pathways. While agonists and antagonists have traditionally been pursued to target GPCRs, allosteric modulators provide several mechanistic advantages, including the ability to distinguish between closely related receptor subtypes. Recently, the discovery of allosteric ligands that confer bias and modulate some, but not all, of a given receptor's downstream signaling pathways can provide pharmacological modulation of brain circuitry with remarkable precision. In addition, allosteric modulators with unprecedented specificity have been developed that can differentiate between subpopulations of a given receptor subtype based on the receptor's dimerization state. These advances are not only providing insight into the biological roles of specific receptor populations, but hold great promise for treating numerous CNS disorders.
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Affiliation(s)
- Daniel J Foster
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA.
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27
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Maksymetz J, Moran SP, Conn PJ. Targeting metabotropic glutamate receptors for novel treatments of schizophrenia. Mol Brain 2017; 10:15. [PMID: 28446243 PMCID: PMC5405554 DOI: 10.1186/s13041-017-0293-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/04/2017] [Indexed: 12/22/2022] Open
Abstract
Support for the N-methyl-D-aspartate receptor (NMDAR) hypofunction hypothesis of schizophrenia has led to increasing focus on restoring proper glutamatergic signaling as an approach for treatment of this devastating disease. The ability of metabotropic glutamate (mGlu) receptors to modulate glutamatergic neurotransmission has thus attracted considerable attention for the development of novel antipsychotics. Consisting of eight subtypes classified into three groups based on sequence homology, signal transduction, and pharmacology, the mGlu receptors provide a wide range of targets to modulate NMDAR function as well as glutamate release. Recently, allosteric modulators of mGlu receptors have been developed that allow unprecedented selectivity among subtypes, not just groups, facilitating the investigation of the effects of subtype-specific modulation. In preclinical animal models, positive allosteric modulators (PAMs) of the group I mGlu receptor mGlu5 have efficacy across all three symptom domains of schizophrenia (positive, negative, and cognitive). The discovery and development of mGlu5 PAMs that display unique signal bias suggests that efficacy can be retained while avoiding the neurotoxic effects of earlier compounds. Interestingly, mGlu1 negative allosteric modulators (NAMs) appear efficacious in positive symptom models of the disease but are still in early preclinical development. While selective group II mGlu receptor (mGlu2/3) agonists have reached clinical trials but were unsuccessful, specific mGlu2 or mGlu3 receptor targeting still hold great promise. Genetic studies implicated mGlu2 in the antipsychotic effects of group II agonists and mGlu2 PAMs have since entered into clinical trials. Additionally, mGlu3 appears to play an important role in cognition, may confer neuroprotective effects, and thus is a promising target to alleviate cognitive deficits in schizophrenia. Although group III mGlu receptors (mGlu4/6/7/8) have attracted less attention, mGlu4 agonists and PAMs appear to have efficacy across all three symptoms domains in preclinical models. The recent discovery of heterodimers comprising mGlu2 and mGlu4 may explain the efficacy of mGlu4 selective compounds but this remains to be determined. Taken together, compounds targeting mGlu receptors, specifically subtype-selective allosteric modulators, provide a compelling alternative approach to fill the unmet clinical needs for patients with schizophrenia.
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Affiliation(s)
- James Maksymetz
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232 USA
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
| | - Sean P. Moran
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232 USA
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232 USA
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232 USA
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28
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Galambos J, Bielik A, Krasavin M, Orgován Z, Domány G, Nógrádi K, Wágner G, Balogh GT, Béni Z, Kóti J, Szakács Z, Bobok A, Kolok S, Mikó-Bakk ML, Vastag M, Sághy K, Laszy J, Halász AS, Balázs O, Gál K, Greiner I, Szombathelyi Z, Keserű GM. Discovery and Preclinical Characterization of 3-((4-(4-Chlorophenyl)-7-fluoroquinoline-3-yl)sulfonyl)benzonitrile, a Novel Non-acetylenic Metabotropic Glutamate Receptor 5 (mGluR5) Negative Allosteric Modulator for Psychiatric Indications. J Med Chem 2017; 60:2470-2484. [DOI: 10.1021/acs.jmedchem.6b01858] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- János Galambos
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Attila Bielik
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Mikhail Krasavin
- Institute
of Chemistry, Saint Petersburg State University, 26 Universitetskii Prospekt, Peterhof, 198504 Russia
| | - Zoltán Orgován
- Medicinal
Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 2 Magyar tudósok körútja, Budapest, 1117 Hungary
| | - György Domány
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Katalin Nógrádi
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Gábor Wágner
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | | | - Zoltán Béni
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - János Kóti
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Zoltán Szakács
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Amrita Bobok
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Sándor Kolok
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | | | - Mónika Vastag
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Katalin Sághy
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Judit Laszy
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | | | - Ottilia Balázs
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - Krisztina Gál
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | - István Greiner
- Gedeon Richter Plc, 19-21 Gyömrői
út, Budapest, 1103 Hungary
| | | | - György M. Keserű
- Medicinal
Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 2 Magyar tudósok körútja, Budapest, 1117 Hungary
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29
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Leach K, Gregory KJ. Molecular insights into allosteric modulation of Class C G protein-coupled receptors. Pharmacol Res 2017; 116:105-118. [DOI: 10.1016/j.phrs.2016.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 11/18/2016] [Accepted: 12/07/2016] [Indexed: 12/23/2022]
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30
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Biased allosteric agonism and modulation of metabotropic glutamate receptor 5: Implications for optimizing preclinical neuroscience drug discovery. Neuropharmacology 2016; 115:60-72. [PMID: 27392634 DOI: 10.1016/j.neuropharm.2016.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 06/30/2016] [Accepted: 07/01/2016] [Indexed: 12/20/2022]
Abstract
Allosteric modulators, that exhibit no intrinsic agonist activity, offer the advantage of spatial and temporal fine-tuning of endogenous agonist activity, allowing the potential for increased selectivity, reduced adverse effects and improved clinical outcomes. Some allosteric ligands can differentially activate and/or modulate distinct signaling pathways arising from the same receptor, phenomena referred to as 'biased agonism' and 'biased modulation'. Emerging evidence for CNS disorders with glutamatergic dysfunction suggests the metabotropic glutamate receptor subtype 5 (mGlu5) is a promising target. Current mGlu5 allosteric modulators have largely been classified based on modulation of intracellular calcium (iCa2+) responses to orthosteric agonists alone. We assessed eight mGlu5 allosteric modulators previously classified as mGlu5 PAMs or PAM-agonists representing four distinct chemotypes across multiple measures of receptor activity, to explore their potential for engendering biased agonism and/or modulation. Relative to the reference orthosteric agonist, DHPG, the eight allosteric ligands exhibited distinct biased agonism fingerprints for iCa2+ mobilization, IP1 accumulation and ERK1/2 phosphorylation in HEK293A cells stably expressing mGlu5 and in cortical neuron cultures. VU0424465, DPFE and VU0409551 displayed the most disparate biased signaling fingerprints in both HEK293A cells and cortical neurons that may account for the marked differences observed previously for these ligands in vivo. Select mGlu5 allosteric ligands also showed 'probe dependence' with respect to their cooperativity with different orthosteric agonists, as well as biased modulation for the magnitude of positive cooperativity observed. Unappreciated biased agonism and modulation may contribute to unanticipated effects (both therapeutic and adverse) when translating from recombinant systems to preclinical models. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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31
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Park J, Moghaddam B. Impact of anxiety on prefrontal cortex encoding of cognitive flexibility. Neuroscience 2016; 345:193-202. [PMID: 27316551 DOI: 10.1016/j.neuroscience.2016.06.013] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 06/06/2016] [Accepted: 06/08/2016] [Indexed: 10/21/2022]
Abstract
Anxiety often is studied as a stand-alone construct in laboratory models. But in the context of coping with real-life anxiety, its negative impacts extend beyond aversive feelings and involve disruptions in ongoing goal-directed behaviors and cognitive functioning. Critical examples of cognitive constructs affected by anxiety are cognitive flexibility and decision making. In particular, anxiety impedes the ability to shift flexibly between strategies in response to changes in task demands, as well as the ability to maintain a strategy in the presence of distractors. The brain region most critically involved in behavioral flexibility is the prefrontal cortex (PFC), but little is known about how anxiety impacts PFC encoding of internal and external events that are critical for flexible behavior. Here we review animal and human neurophysiological and neuroimaging studies implicating PFC neural processing in anxiety-induced deficits in cognitive flexibility. We then suggest experimental and analytical approaches for future studies to gain a better mechanistic understanding of impaired cognitive inflexibility in anxiety and related disorders.
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Affiliation(s)
- Junchol Park
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bita Moghaddam
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.
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32
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LaCrosse AL, Taylor SB, Nemirovsky NE, Gass JT, Olive MF. mGluR5 Positive and Negative Allosteric Modulators Differentially Affect Dendritic Spine Density and Morphology in the Prefrontal Cortex. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2016; 14:476-85. [PMID: 25921744 DOI: 10.2174/1871527314666150429112849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 01/17/2015] [Accepted: 01/19/2015] [Indexed: 12/31/2022]
Abstract
Positive and negative allosteric modulators (PAMs and NAMs, respectively) of type 5 metabotropic glutamate receptors (mGluR5) are currently being investigated as novel treatments for neuropsychiatric diseases including drug addiction, schizophrenia, and Fragile X syndrome. However, only a handful of studies have examined the effects of mGluR5 PAMs or NAMs on the structural plasticity of dendritic spines in otherwise naïve animals, particularly in brain regions mediating executive function. In the present study, we assessed dendritic spine density and morphology in pyramidal cells of the medial prefrontal cortex (mPFC) after repeated administration of either the prototypical mGluR5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5- yl)benzamide (CDPPB, 20 mg/kg), the clinically utilized mGluR5 NAM 1-(3-chlorophenyl)-3-(3-methyl-5-oxo-4Himidazol- 2-yl)urea (fenobam, 20 mg/kg), or vehicle in male Sprague-Dawley rats. Following once daily treatment for 10 consecutive days, coronal brain sections containing the mPFC underwent diolistic labeling and 3D image analysis of dendritic spines. Compared to vehicle treated animals, rats administered fenobam exhibited significant increases in dendritic spine density and the overall frequency of spines with small (<0.2 μm) head diameters, decreases in frequency of spines with medium (0.2-0.4 μm) head diameters, and had no changes in frequency of spines with large head diameters (>0.4 μm). Administration of CDPPB had no discernable effects on dendritic spine density or morphology, and neither CDPPB nor fenobam had any effect on spine length or volume. We conclude that mGluR5 PAMs and NAMs differentially affect mPFC dendritic spine structural plasticity in otherwise naïve animals, and additional studies assessing their effects in combination with cognitive or behavioral tasks are needed.
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Affiliation(s)
| | | | | | | | - Michael F Olive
- Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287, USA.
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33
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Lins BR, Howland JG. Effects of the metabotropic glutamate receptor 5 positive allosteric modulator CDPPB on rats tested with the paired associates learning task in touchscreen-equipped operant conditioning chambers. Behav Brain Res 2015; 301:152-60. [PMID: 26721467 DOI: 10.1016/j.bbr.2015.12.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/30/2015] [Accepted: 12/17/2015] [Indexed: 02/03/2023]
Abstract
Effective treatments for the cognitive symptoms of schizophrenia are critically needed. Positive allosteric modulation (PAM) of metabotropic glutamate receptor subtype 5 (mGluR5) is one strategy currently under investigation to improve these symptoms. Examining cognition using touchscreen-equipped operant chambers may increase translation between preclinical and clinical research through analogous behavioral testing paradigms in rodents and humans. We used acute CDPPB (1-30mg/kg) treatment to examine the effects of mGluR5 PAM in the touchscreen paired associates learning (PAL) task using well-trained rats with and without co-administration of acute MK-801 (0.15mg/kg). CDPPB had no consistent effects on task performance when administered alone and failed to reverse the MK-801 induced impairments at any of the examined doses. Overall, the disruptive effects of MK-801 on PAL were consistent with previous research but increasing mGluR5 signaling is not beneficial in the PAL task. Future research should test whether administration of CDPPB during PAL acquisition increases performance.
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Affiliation(s)
- Brittney R Lins
- Department of Physiology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - John G Howland
- Department of Physiology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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Lins BR, Phillips AG, Howland JG. Effects of D- and L-govadine on the disruption of touchscreen object-location paired associates learning in rats by acute MK-801 treatment. Psychopharmacology (Berl) 2015; 232:4371-82. [PMID: 26359226 DOI: 10.1007/s00213-015-4064-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 08/26/2015] [Indexed: 11/26/2022]
Abstract
RATIONALE New pharmacological treatments for the cognitive deficits in schizophrenia are needed. Tetrahydroprotoberberines, such as govadine, are one class of compounds with dopaminergic activities that may be useful in treating some aspects of the cognitive symptoms of the disorder. OBJECTIVE The objective of the present studies was to test the effects of the D- and L-enantiomers of govadine on the impairment in a paired-associate learning (PAL) task produced by acute MK-801 in rats. We also assessed effects of the typical antipsychotic haloperidol as a comparator compound. METHODS MK-801 (0.05, 0.1, 0.15, and 0.2 mg/kg), D- and L-govadine (0.3, 1.0, and 3.0 mg/kg), and haloperidol (0.05, 0.1, and 0.25 mg/kg) were administered acutely to rats well trained on the PAL task in touchscreen-equipped operant conditioning chambers. RESULTS Acute MK-801 impaired performance of PAL in a dose-dependent manner by reducing accuracy and increasing correction trials. L-Govadine (1.0 mg/kg), but not D-govadine, blocked the disruptive effects of MK-801 (0.15 mg/kg) on PAL. Haloperidol failed to affect the MK-801-induced disruption of PAL. Higher doses of L-govadine and haloperidol dramatically impaired performance of the task which confounded interpretation of cognitive outcomes. CONCLUSION L-Govadine appears unique in its ability to improve performance of the MK-801-induced impairment in the PAL task. This behavioral effect may relate the ability of L-govadine to antagonize dopamine D2 receptors while also promoting dopamine efflux. Future research should further characterize the role of the dopamine system in the rodent PAL task to elucidate the mechanisms of its pro-cognitive effects.
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Affiliation(s)
- Brittney R Lins
- Department of Physiology, University of Saskatchewan, GB33, Health Sciences Building, 107 Wiggins Rd, Saskatoon, SK, Canada, S7N 5E5
| | - Anthony G Phillips
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada, V6T 2A1
| | - John G Howland
- Department of Physiology, University of Saskatchewan, GB33, Health Sciences Building, 107 Wiggins Rd, Saskatoon, SK, Canada, S7N 5E5.
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Isherwood SN, Pekcec A, Nicholson JR, Robbins TW, Dalley JW. Dissociable effects of mGluR5 allosteric modulation on distinct forms of impulsivity in rats: interaction with NMDA receptor antagonism. Psychopharmacology (Berl) 2015; 232:3327-44. [PMID: 26063678 DOI: 10.1007/s00213-015-3984-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/29/2015] [Indexed: 02/03/2023]
Abstract
RATIONALE Impaired N-methyl-D-aspartate (NMDA) receptor signalling underlies several psychiatric disorders that express high levels of impulsivity. Although synergistic interactions exist between NMDA receptors and metabotropic glutamate receptor 5 (mGluR5), the significance of this interaction for impulsivity is unknown. OBJECTIVE This study aims to investigate the effects of negative and positive allosteric mGluR5 modulation (NAM/PAM) on trait impulsivity and impulsivity evoked by NMDA receptor antagonism in rats. METHODS Motor and choice impulsivity were assessed using the five-choice serial reaction time task (5-CSRTT) and delayed-discounting task (DDT), respectively. The effects of RO4917523 and 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) (NAMs) and ADX47273 (PAM) were investigated in non-impulsive rats and in trait high- and low-impulsive rats. The effects of these compounds on impulsivity induced by NMDA receptor antagonism (MK801) in the 5-CSRTT were also investigated. RESULTS RO4917523 (0.1-1 mg/kg) decreased premature responding and increased omissions but had no effect on locomotor activity up to 0.1 mg/kg. MTEP significantly increased omissions, decreased accuracy and slowed responding but had no effect on premature responding. ADX47273 decreased premature responding at doses that had no effect on locomotor activity. MK801 increased premature responding and impaired attentional accuracy; these deficits were dose dependently rescued by ADX47273 pre-treatment. Allosteric modulation of mGluR5 had no significant effect on choice impulsivity, nor did it modulate general task performance. CONCLUSIONS These findings demonstrate that mGluR5 allosteric modulation selectively dissociates motor and choice impulsivity. We further show that mGluR5 PAMs may have therapeutic utility in selectively targeting specific aspects of impulsivity and executive dysfunction.
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Affiliation(s)
- Sarah N Isherwood
- Boehringer Ingelheim Pharma GmbH & Co. KG, Div. Research Germany, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany
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Svoboda J, Stankova A, Entlerova M, Stuchlik A. Acute administration of MK-801 in an animal model of psychosis in rats interferes with cognitively demanding forms of behavioral flexibility on a rotating arena. Front Behav Neurosci 2015; 9:75. [PMID: 25883558 PMCID: PMC4381641 DOI: 10.3389/fnbeh.2015.00075] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/10/2015] [Indexed: 01/10/2023] Open
Abstract
Patients with schizophrenia often manifest deficits in behavioral flexibility. Non-competitive NMDA receptor antagonists such as MK-801 induce schizophrenia-like symptoms in rodents, including cognitive functions. Despite work exploring flexibility has been done employing behavioral paradigms with simple stimuli, much less is known about what kinds of flexibility are affected in an MK-801 model of schizophrenia-like behavior in the spatial domain. We used a rotating arena-based apparatus (Carousel) requiring rats to avoid an unmarked sector defined in either the reference frame of the rotating arena (arena frame task, AF) or the stationary room (room frame task, RF). We investigated behavioral flexibility in four conditions involving different cognitive loads. Each condition encompassed an initial (five sessions) and a test phase (five sessions) in which some aspects of the task were changed to test flexibility and in which rats were given saline, 0.05 mg/kg or 0.1 mg/kg MK-801 thirty minutes prior to a session. In the first condition, rats acquired avoidance in RF with clockwise rotation of the arena while in the test phase the arena rotated counterclockwise. In the second condition, rats initially acquired avoidance in RF with the sector on the north and then it was reversed to south (spatial reversal). In the third and fourth conditions, rats initially performed an AF (RF, respectively) task, followed by an RF (AF, respectively) task, testing the ability of cognitive set-shifting. We found no effect of MK-801 either on simple motor adjustment after reversal of arena rotation or on spatial reversal within the RF. In contrast, administration of MK-801 at a dose of 0.1 mg/kg interfered with set-shifting in both conditions. Furthermore, we observed MK-801 0.1 mg/kg elevated locomotion in all cases. These data suggest that blockade of NMDA receptors by acute system administration of MK-801 preferentially affects set-shifting in the cognitive domain rather than reversal.
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Affiliation(s)
- Jan Svoboda
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Anna Stankova
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic ; Laboratory of Neurobehavioral Studies, National Institute of Mental Health Klecany, Prague, Czech Republic
| | - Marie Entlerova
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Ales Stuchlik
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic ; Laboratory of Neurobehavioral Studies, National Institute of Mental Health Klecany, Prague, Czech Republic
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mGluR5 positive allosteric modulation and its effects on MK-801 induced set-shifting impairments in a rat operant delayed matching/non-matching-to-sample task. Psychopharmacology (Berl) 2015; 232:251-8. [PMID: 24973895 PMCID: PMC4278949 DOI: 10.1007/s00213-014-3653-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 06/08/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Positive allosteric modulators (PAMs) of type 5 metabotropic glutamate receptors (mGluR5) exert pro-cognitive effects in animal models of various neuropsychiatric diseases. However, few studies to date have examined ability of mGluR5 PAMs to reverse cognitive deficits in operant delayed matching/non-matching-to-sample (DMS/DNMS) tasks. OBJECTIVES This study aims to determine the ability of the mGluR5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) to reverse set-shifting deficits induced by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801. METHODS Male Sprague-Dawley rats were initially trained to lever press for sucrose reinforcement under either DMS or DNMS conditions. Following successful acquisition of the task, reinforcement conditions were reversed (DNMS → DMS or DMS → DNMS). In Experiment 1, rats were treated daily prior to each session with vehicle/vehicle, vehicle/MK-801 (0.06 mg/kg) simultaneously, CDPPB (20 mg/kg)/MK-801 simultaneously, or CDPPB 30 min prior to MK-801. In Experiment 2, rats were treated with either vehicle/vehicle, vehicle/MK-801, or CDPPB 30 min prior to MK-801 only prior to sessions that followed task reversal. RESULTS In Experiment 1, no group differences in initial task acquisition were observed. Rats treated with vehicle/MK-801 showed significant set-shifting impairments following task reversal, which were partially attenuated by simultaneous administration of CDPPB/MK-801 and completely precluded by administration of CDPPB 30 min prior to MK-801. In Experiment 2, MK-801 did not impair reversal learning, and no other group differences were observed. CONCLUSIONS MK-801-induced deficits in operant set-shifting ability were prevented by pretreatment with CDPPB. MK-801 did not produce deficits in task learning when treatment was initiated following task reversal.
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Guan DF, Ren PY, Hu W, Zhang YL. The mGluR5 Positive Allosteric Modulator CDPPB Inhibits SO2-Induced Protein Radical Formation and Mitochondrial Dysfunction Through Activation of Akt in Mouse Hippocampal HT22 Cells. Cell Mol Neurobiol 2014; 35:573-83. [DOI: 10.1007/s10571-014-0153-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/23/2014] [Indexed: 11/30/2022]
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Adolescent alcohol exposure reduces behavioral flexibility, promotes disinhibition, and increases resistance to extinction of ethanol self-administration in adulthood. Neuropsychopharmacology 2014; 39:2570-83. [PMID: 24820536 PMCID: PMC4207336 DOI: 10.1038/npp.2014.109] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 05/01/2014] [Accepted: 05/02/2014] [Indexed: 02/07/2023]
Abstract
The prefrontal cortex (PFC) is a brain region that is critically involved in cognitive function and inhibitory control of behavior, and adolescence represents an important period of continued PFC development that parallels the maturation of these functions. Evidence suggests that this period of continued development of the PFC may render it especially vulnerable to environmental insults that impact PFC function in adulthood. Experimentation with alcohol typically begins during adolescence when binge-like consumption of large quantities is common. In the present study, we investigated the effects of repeated cycles of adolescent intermittent ethanol (AIE) exposure (postnatal days 28-42) by vapor inhalation on different aspects of executive functioning in the adult rat. In an operant set-shifting task, AIE-exposed rats exhibited deficits in their ability to shift their response strategy when the rules of the task changed, indicating reduced behavioral flexibility. There were no differences in progressive ratio response for the reinforcer suggesting that AIE did not alter reinforcer motivation. Examination of performance on the elevated plus maze under conditions designed to minimize stress revealed that AIE exposure enhanced the number of entries into the open arms, which may reflect either reduced anxiety and/or disinhibition of exploratory-like behavior. In rats that trained to self-administer ethanol in an operant paradigm, AIE increased resistance to extinction of ethanol-seeking behavior. This resistance to extinction was reversed by positive allosteric modulation of mGluR5 during extinction training, an effect that is thought to reflect promotion of extinction learning mechanisms within the medial PFC. Consistent with this, CDPPB was also observed to reverse the deficits in behavioral flexibility. Finally, diffusion tensor imaging with multivariate analysis of 32 brain areas revealed that while there were no differences in the total brain volume, the volume of a subgroup of regions (hippocampus, thalamus, dorsal striatum, neocortex, and hypothalamus) were significantly different in AIE-exposed adults compared with litter-matched Control rats. Taken together, these findings demonstrate that binge-like exposure to alcohol during early to middle adolescence results in deficits in PFC-mediated behavioral control in adulthood.
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Stress hormone exposure reduces mGluR5 expression in the nucleus accumbens: functional implications for interoceptive sensitivity to alcohol. Neuropsychopharmacology 2014; 39:2376-86. [PMID: 24713611 PMCID: PMC4138747 DOI: 10.1038/npp.2014.85] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/11/2014] [Accepted: 04/02/2014] [Indexed: 12/19/2022]
Abstract
Escalations in alcohol drinking associated with experiencing stressful life events and chronic life stressors may be related to altered sensitivity to the interoceptive/subjective effects of alcohol. Indeed, through the use of drug discrimination methods, rats show decreased sensitivity to the discriminative stimulus (interoceptive) effects of alcohol following exposure to the stress hormone corticosterone (CORT). This exposure produces heightened elevations in plasma CORT levels (eg, as may be experienced by an individual during stressful episodes). We hypothesized that decreased sensitivity to alcohol may be related, in part, to changes in metabotropic glutamate receptors-subtype 5 (mGluR5) in the nucleus accumbens, as these receptors in this brain region are known to regulate the discriminative stimulus effects of alcohol. In the accumbens, we found reduced mGluR5 expression (immunohistochemistry and Western blot) and decreased neural activation (as measured by c-Fos immunohistochemistry) in response to a moderate alcohol dose (1 g/kg) following CORT exposure (7 days). The functional role of these CORT-induced adaptations in relation to the discriminative stimulus effects of alcohol was confirmed, as both the systemic administration of 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) an mGluR5 positive allosteric modulator and the intra-accumbens administration of (R,S)-2-Amino-2-(2-chloro-5-hydroxyphenyl)acetic acid sodium salt (CHPG) an mGluR5 agonist restored sensitivity to alcohol in discrimination-trained rats. These results suggest that activation of mGluR5 may alleviate the functional impact of the CORT-induced downregulation of mGluR5 in relation to sensitivity to alcohol. Understanding the contribution of such neuroadaptations to the interoceptive effects of alcohol may enrich our understanding of potential changes in subjective sensitivity to alcohol during stressful episodes.
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Zavodnick AD, Ali R. N-Acetylcysteine and metabotropic glutamate receptors: implications for the treatment of schizophrenia: a literature review. Psychiatr Q 2014; 85:177-85. [PMID: 24390716 DOI: 10.1007/s11126-013-9281-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The objective of this study is to review the available data regarding metabotropic glutamate receptors in the pathology of Schizophrenia. Further, to investigate the potential utility of N-acetylcysteine as it relates to metabotropic glutamate receptors. A PubMed based literature review was conducted using keywords related to glutamate receptors, Schizophrenia and N-acetylcysteine from June 2012 through August of 2012. Relevant cited references of selected articles were also reviewed. The knowledge base regarding glutamate receptors, both ionotropic and metabotropic is rapidly expanding. New agonists of various subsets of metabotropic glutamate receptors are available and have demonstrated potential utility in animal models. N-acetylcysteine indirectly stimulates presynaptic metabotropic glutamate receptors and has shown efficacy in two double-blind randomized controlled trials. Metabotropic glutamate receptors contribute to an understanding of glutamate dysfunction in Schizophrenia. Agents which lead to stimulation of metabotropic glutamate receptors, inclusive of N-acetylcysteine show promise as novel agents in the treatment of this disorder. An understanding of the various metabotropic glutamate receptors will be a growing necessity as agents which target them continue to emerge and enter clinical trials.
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Affiliation(s)
- Adam Daniel Zavodnick
- Psychiatry Intern, Department of Psychiatry and Behavioral Medicine, Carilion Clinic - Virginia Tech Carilion School of Medicine, Roanoke, VA, USA,
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Increased response to glutamate in small diameter dorsal root ganglion neurons after sciatic nerve injury. PLoS One 2014; 9:e95491. [PMID: 24748330 PMCID: PMC3991716 DOI: 10.1371/journal.pone.0095491] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 03/26/2014] [Indexed: 12/24/2022] Open
Abstract
Glutamate in the peripheral nervous system is involved in neuropathic pain, yet we know little how nerve injury alters responses to this neurotransmitter in primary sensory neurons. We recorded neuronal responses from the ex-vivo preparations of the dorsal root ganglia (DRG) one week following a chronic constriction injury (CCI) of the sciatic nerve in adult rats. We found that small diameter DRG neurons (<30 µm) exhibited increased excitability that was associated with decreased membrane threshold and rheobase, whereas responses in large diameter neurons (>30 µm) were unaffected. Puff application of either glutamate, or the selective ionotropic glutamate receptor agonists alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainic acid (KA), or the group I metabotropic receptor (mGluR) agonist (S)-3,5-dihydroxyphenylglycine (DHPG), induced larger inward currents in CCI DRGs compared to those from uninjured rats. N-methyl-D-aspartate (NMDA)-induced currents were unchanged. In addition to larger inward currents following CCI, a greater number of neurons responded to glutamate, AMPA, NMDA, and DHPG, but not to KA. Western blot analysis of the DRGs revealed that CCI resulted in a 35% increase in GluA1 and a 60% decrease in GluA2, the AMPA receptor subunits, compared to uninjured controls. mGluR1 receptor expression increased by 60% in the membrane fraction, whereas mGluR5 receptor subunit expression remained unchanged after CCI. These results show that following nerve injury, small diameter DRG neurons, many of which are nociceptive, have increased excitability and an increased response to glutamate that is associated with changes in receptor expression at the neuronal membrane. Our findings provide further evidence that glutamatergic transmission in the periphery plays a role in nociception.
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Effect of alpha7 nicotinic acetylcholine receptor agonists on attentional set-shifting impairment in rats. Psychopharmacology (Berl) 2014; 231:673-83. [PMID: 24057763 DOI: 10.1007/s00213-013-3275-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 09/03/2013] [Indexed: 11/27/2022]
Abstract
RATIONALE Attentional set shifting, a measure of executive function, is impaired in schizophrenia patients. Current standard of care has little therapeutic benefit for treating cognitive dysfunction in schizophrenia; therefore, novel drugs and animal models for testing novel therapies are needed. The NMDA receptor antagonist, MK-801, produces deficits in a rat maze-based set-shifting paradigm, an effect which parallels deficits observed on tests of executive function in schizophrenia patients. Alpha7 nicotinic acetylcholine receptor (nAChR) agonists, currently under clinical development by several companies, show promise in treating cognitive symptoms in schizophrenia patients and can improve cognition in various animal models. OBJECTIVES The objectives of the present study were to determine whether the MK-801 deficit in set shifting could be reproduced in a drug discovery setting and to determine whether cognitive improvement could be detected for the first time in this task with alpha7 nAChR agonists. RESULTS The data presented here replicate findings that a systemic injection of the NMDA receptor antagonist MK-801 can induce a deficit in set shifting in rats. Furthermore, the deficit could be reversed by the atypical antipsychotic clozapine as well as by several alpha7 nAch receptor agonists (SSR-180711, PNU-282987, GTS-21) with varying in vitro properties. CONCLUSIONS Results indicate that the MK-801 set-shift assay is a useful preclinical tool for measuring prefrontal cortical function in rodents and can be used to identify novel mechanisms for the potential treatment of cognitive deficits in schizophrenia.
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Nickols HH, Conn PJ. Development of allosteric modulators of GPCRs for treatment of CNS disorders. Neurobiol Dis 2014; 61:55-71. [PMID: 24076101 PMCID: PMC3875303 DOI: 10.1016/j.nbd.2013.09.013] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/13/2013] [Accepted: 09/17/2013] [Indexed: 12/14/2022] Open
Abstract
The discovery of allosteric modulators of G protein-coupled receptors (GPCRs) provides a promising new strategy with potential for developing novel treatments for a variety of central nervous system (CNS) disorders. Traditional drug discovery efforts targeting GPCRs have focused on developing ligands for orthosteric sites which bind endogenous ligands. Allosteric modulators target a site separate from the orthosteric site to modulate receptor function. These allosteric agents can either potentiate (positive allosteric modulator, PAM) or inhibit (negative allosteric modulator, NAM) the receptor response and often provide much greater subtype selectivity than orthosteric ligands for the same receptors. Experimental evidence has revealed more nuanced pharmacological modes of action of allosteric modulators, with some PAMs showing allosteric agonism in combination with positive allosteric modulation in response to endogenous ligand (ago-potentiators) as well as "bitopic" ligands that interact with both the allosteric and orthosteric sites. Drugs targeting the allosteric site allow for increased drug selectivity and potentially decreased adverse side effects. Promising evidence has demonstrated potential utility of a number of allosteric modulators of GPCRs in multiple CNS disorders, including neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, as well as psychiatric or neurobehavioral diseases such as anxiety, schizophrenia, and addiction.
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Key Words
- (+)-6-(2,4-dimethylphenyl)-2-ethyl-6,7-dihydrobenzo[d]oxazol-4(5H)-one
- (1-(4-cyano-4-(pyridine-2-yl)piperidine-1-yl)methyl-4-oxo-4H-quinolizine-3-carboxylic acid)
- (1S,2S)-N(1)-(3,4-dichlorophenyl)cyclohexane-1,2-dicarboxamide
- (1S,3R,4S)-1-aminocyclo-pentane-1,3,4-tricarboxylic acid
- (3,4-dihydro-2H-pyrano[2,3]b quinolin-7-yl)(cis-4-methoxycyclohexyl) methanone
- (3aS,5S,7aR)-methyl 5-hydroxy-5-(m-tolylethynyl)octahydro-1H-indole-1-carboxylate
- 1-(1′-(2-methylbenzyl)-1,4′-bipiperidin-4-yl)-1H-benzo[d]imidazol-2(3H)-one
- 1-[3-(4-butyl-1-piperidinyl)propyl]-3,4-dihydro-2(1H)-quinolinone
- 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- 2-(2-(3-methoxyphenyl)ethynyl)-5-methylpyridine
- 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1Himidazol-4-yl)ethynyl)pyridine
- 2-methyl-6-(2-phenylethenyl)pyridine
- 2-methyl-6-(phenylethynyl)-pyridine
- 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide
- 3-cyclohexyl-5-fluoro-6-methyl-7-(2-morpholin-4-ylethoxy)-4H-chromen-4-one
- 3[(2-methyl-1,3-thiazol-4-yl)ethylnyl]pyridine
- 4-((E)-styryl)-pyrimidin-2-ylamine
- 4-[1-(2-fluoropyridin-3-yl)-5-methyl-1H-1,2,3-triazol-4-yl]-N-isopropyl-N-methyl-3,6-dihydropyridine-1(2H)-carboxamide
- 4-n-butyl-1-[4-(2-methylphenyl)-4-oxo-1-butyl]-piperidine
- 5-methyl-6-(phenylethynyl)-pyridine
- 5MPEP
- 6-(4-methoxyphenyl)-5-methyl-3-(4-pyridinyl)-isoxazolo[4,5-c]pyridin-4(5H)-one
- 6-OHDA
- 6-hydroxydopamine
- 6-methyl-2-(phenylazo)-3-pyridinol
- 77-LH-28-1
- 7TMR
- AC-42
- ACPT-1
- AChE
- AD
- ADX71743
- AFQ056
- APP
- Allosteric modulator
- Alzheimer's disease
- BINA
- BQCA
- CDPPB
- CFMMC
- CNS
- CPPHA
- CTEP
- DA
- DFB
- DHPG
- Drug discovery
- ERK1/2
- FMRP
- FTIDC
- FXS
- Fragile X syndrome
- GABA
- GPCR
- JNJ16259685
- L-AP4
- L-DOPA
- Lu AF21934
- Lu AF32615
- M-5MPEP
- MMPIP
- MPEP
- MPTP
- MTEP
- Metabotropic glutamate receptor
- Muscarinic acetylcholine receptor
- N-[4-chloro-2[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]phenyl]-2-hydrobenzamide
- N-methyl-d-aspartate
- N-phenyl-7-(hydroxylimino)cyclopropa[b]chromen-1a-carboxamide
- NAM
- NMDA
- PAM
- PCP
- PD
- PD-LID
- PET
- PHCCC
- PQCA
- Parkinson's disease
- Parkinson's disease levodopa-induced dyskinesia
- SAM
- SIB-1757
- SIB-1893
- TBPB
- [(3-fluorophenyl)methylene]hydrazone-3-fluorobenzaldehyde
- acetylcholinesterase
- amyloid precursor protein
- benzylquinolone carboxylic acid
- central nervous system
- dihydroxyphenylglycine
- dopamine
- extracellular signal-regulated kinase 1/2
- fragile X mental retardation protein
- l-(+)-2-amino-4-phosphonobutyric acid
- l-3,4-dihydroxyphenylalanine
- mGlu
- metabotropic glutamate receptor
- negative allosteric modulator
- phencyclidine
- positive allosteric modulator
- positron emission tomography
- potassium 30-([(2-cyclopentyl-6-7-dimethyl-1-oxo-2,3-dihydro-1H-inden-5yl)oxy]methyl)biphenyl l-4-carboxylate
- seven transmembrane receptor
- silent allosteric modulator
- γ-aminobutyric acid
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Affiliation(s)
- Hilary Highfield Nickols
- Division of Neuropathology, Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN, 37232, USA
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
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Leading compounds for the validation of animal models of psychopathology. Cell Tissue Res 2013; 354:309-30. [DOI: 10.1007/s00441-013-1692-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/01/2013] [Indexed: 12/18/2022]
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Won H, Mah W, Kim E. Autism spectrum disorder causes, mechanisms, and treatments: focus on neuronal synapses. Front Mol Neurosci 2013; 6:19. [PMID: 23935565 PMCID: PMC3733014 DOI: 10.3389/fnmol.2013.00019] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/16/2013] [Indexed: 12/24/2022] Open
Abstract
Autism spectrum disorder (ASD) is a group of developmental disabilities characterized by impairments in social interaction and communication and restricted and repetitive interests/behaviors. Advances in human genomics have identified a large number of genetic variations associated with ASD. These associations are being rapidly verified by a growing number of studies using a variety of approaches, including mouse genetics. These studies have also identified key mechanisms underlying the pathogenesis of ASD, many of which involve synaptic dysfunctions, and have investigated novel, mechanism-based therapeutic strategies. This review will try to integrate these three key aspects of ASD research: human genetics, animal models, and potential treatments. Continued efforts in this direction should ultimately reveal core mechanisms that account for a larger fraction of ASD cases and identify neural mechanisms associated with specific ASD symptoms, providing important clues to efficient ASD treatment.
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Affiliation(s)
- Hyejung Won
- Department of Biological Sciences, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Won Mah
- Department of Biological Sciences, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeon, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeon, South Korea
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Cioffi CL. Modulation of NMDA receptor function as a treatment for schizophrenia. Bioorg Med Chem Lett 2013; 23:5034-44. [PMID: 23916256 DOI: 10.1016/j.bmcl.2013.07.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 07/03/2013] [Accepted: 07/13/2013] [Indexed: 11/30/2022]
Abstract
Schizophrenia is a devastating mental illness that afflicts nearly 1% of the world's population. Currently available antipsychotics treat positive symptoms, but are largely ineffective at addressing negative symptoms and cognitive dysfunction. Thus, improved pharmacotherapies that treat all aspects of the disease remain a critical unmet need. There is mounting evidence that links NMDA receptor hypofunction and the expression of schizophrenia, and numerous drug discovery programs have developed agents that directly or indirectly potentiate NMDA receptor-mediated neurotransmission. Several compounds have emerged that show promise for treating all symptom sub-domains in both preclinical models and clinical studies, and we will review recent developments in many of these areas.
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48
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Xu J, Zhu Y, Kraniotis S, He Q, Marshall JJ, Nomura T, Stauffer SR, Lindsley CW, Conn PJ, Contractor A. Potentiating mGluR5 function with a positive allosteric modulator enhances adaptive learning. Learn Mem 2013; 20:438-45. [PMID: 23869026 PMCID: PMC3718201 DOI: 10.1101/lm.031666.113] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Metabotropic glutamate receptor 5 (mGluR5) plays important roles in modulating neural activity and plasticity and has been associated with several neuropathological disorders. Previous work has shown that genetic ablation or pharmacological inhibition of mGluR5 disrupts fear extinction and spatial reversal learning, suggesting that mGluR5 signaling is required for different forms of adaptive learning. Here, we tested whether ADX47273, a selective positive allosteric modulator (PAM) of mGluR5, can enhance adaptive learning in mice. We found that systemic administration of the ADX47273 enhanced reversal learning in the Morris Water Maze, an adaptive task. In addition, we found that ADX47273 had no effect on single-session and multi-session extinction, but administration of ADX47273 after a single retrieval trial enhanced subsequent fear extinction learning. Together these results demonstrate a role for mGluR5 signaling in adaptive learning, and suggest that mGluR5 PAMs represent a viable strategy for treatment of maladaptive learning and for improving behavioral flexibility.
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Affiliation(s)
- Jian Xu
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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49
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Clifton NE, Morisot N, Girardon S, Millan MJ, Loiseau F. Enhancement of social novelty discrimination by positive allosteric modulators at metabotropic glutamate 5 receptors: adolescent administration prevents adult-onset deficits induced by neonatal treatment with phencyclidine. Psychopharmacology (Berl) 2013; 225:579-94. [PMID: 22983144 DOI: 10.1007/s00213-012-2845-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 08/08/2012] [Indexed: 12/20/2022]
Abstract
Metabotropic glutamate-5 receptors (mGluR5), which physically and functionally interact with N-methyl-D-Aspartate (NMDA) receptors, likewise control cognitive processes and have been proposed as targets for novel classes of antipsychotic agent. Since social cognition is impaired in schizophrenia and disrupted by NMDA receptor antagonists like dizocilpine, we evaluated its potential modulation by mGluR5. Acute administration (0.63-40 mg/kg) of the mGluR5 positive allosteric modulators (PAMs), 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) and ADX47273, reversed a delay-induced impairment in social novelty discrimination (SND) in adult rats. The action of CDPPB was blocked by the mGluR5 antagonist, 2-methyl-6-(phenylethynyl)-pyridine (2.5-10 mg/kg), and was also expressed upon microinjection into frontal cortex (0.63-10 μg/side), but not striatum. Supporting an interrelationship between mGluR5 and NMDA receptors, enhancement of SND by CDPPB was blocked by dizocilpine (0.08 mg/kg) while, reciprocally, dizocilpine-induced impairment in SND was attenuated by CDPPB (10 mg/kg). The SND deficit elicited by post-natal administration of phencyclidine (10 mg/kg, days 7-11) was reversed by CDPPB or ADX47273 in adults at week 8. This phencyclidine-induced impairment in cognition emerged in adult rats from week 7 on, and chronic, pre-symptomatic treatment of adolescent rats with CDPPB over weeks 5-6 (10 mg/kg per day) prevented the appearance of SND deficits in adults until at least week 13. In conclusion, as evaluated by a SND procedure, mGluR5 PAMs promote social cognition via actions expressed in interaction with NMDA receptors and exerted in frontal cortex. MGluR5 PAMs not only reverse but also (when given during adolescence) prevent the emergence of cognitive impairment associated with a developmental model of schizophrenia.
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Affiliation(s)
- Nicholas E Clifton
- Neuroscience Research and Development Unit, Institut de Recherches Servier, 125 Chemin de ronde, Croissy-sur-Seine, Paris, France
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In vitro characterisation of the novel positive allosteric modulators of the mGlu5 receptor, LSN2463359 and LSN2814617, and their effects on sleep architecture and operant responding in the rat. Neuropharmacology 2013; 64:224-39. [DOI: 10.1016/j.neuropharm.2012.07.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 07/14/2012] [Accepted: 07/16/2012] [Indexed: 11/18/2022]
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