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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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Song Z, Alpers A, Warner K, Iacobucci F, Hoskins E, Disterhoft JF, Voss JL, Widge AS. Chronic, Reusable, Multiday Neuropixels Recordings during Free-Moving Operant Behavior. eNeuro 2024; 11:ENEURO.0245-23.2023. [PMID: 38253540 PMCID: PMC10849027 DOI: 10.1523/eneuro.0245-23.2023] [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: 06/28/2023] [Revised: 12/13/2023] [Accepted: 12/17/2023] [Indexed: 01/24/2024] Open
Abstract
Electrophysiological recording is a powerful technique to examine neuronal substrates underlying cognition and behavior. Neuropixels probes provide a unique capacity to capture neuronal activity across many brain areas with high spatiotemporal resolution. Neuropixels are also expensive and optimized for acute, head-fixed use, both of which limit the types of behaviors and manipulations that can be studied. Recent advances have addressed the cost issue by showing chronic implant, explant, and reuse of Neuropixels probes, but the methods were not optimized for use in free-moving behavior. There were specific needs for improvement in cabling/connection stability. Here, we extend that work to demonstrate chronic Neuropixels recording, explant, and reuse in a rat model during fully free-moving operant behavior. Similar to prior approaches, we house the probe and headstage within a 3D-printed housing that avoids direct fixation of the probe to the skull, enabling eventual explant. We demonstrate innovations to allow chronic headstage connection with protection against environmental factors and a more stable cabling setup to reduce the tension that can interrupt recording. We demonstrate this approach with rats performing two different behavioral tasks, in each case showing: (1) chronic single- or dual-probe recordings in free-moving rats in operant chambers and (2) reusability of Neuropixels 1.0 probes with continued good single-unit yield after retrieval and reimplant. We thus demonstrate the potential for Neuropixels recordings in a wider range of species and preparations.
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Affiliation(s)
- Zhimin Song
- Department of Psychiatry, University of Minnesota, Minneapolis, 55455 Minnesota
| | - Abigail Alpers
- Department of Psychiatry, University of Minnesota, Minneapolis, 55455 Minnesota
| | - Kasey Warner
- Department of Psychiatry, University of Minnesota, Minneapolis, 55455 Minnesota
| | - Francesca Iacobucci
- Department of Psychiatry, University of Minnesota, Minneapolis, 55455 Minnesota
| | - Eric Hoskins
- Department of Psychiatry, University of Minnesota, Minneapolis, 55455 Minnesota
| | - John F Disterhoft
- Department of Neuroscience, Northwestern University, Evanston, 60208 Illinois
| | - Joel L Voss
- Department of Neurology, University of Chicago, Chicago, 60637 Illinois
| | - Alik S Widge
- Department of Psychiatry, University of Minnesota, Minneapolis, 55455 Minnesota
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Morgan AA, Alves ND, Stevens GS, Yeasmin TT, Mackay A, Power S, Sargin D, Hanna C, Adib AL, Ziolkowski-Blake A, Lambe EK, Ansorge MS. Medial Prefrontal Cortex Serotonin Input Regulates Cognitive Flexibility in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.534775. [PMID: 37034804 PMCID: PMC10081203 DOI: 10.1101/2023.03.30.534775] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The medial prefrontal cortex (mPFC) regulates cognitive flexibility and emotional behavior. Neurons that release serotonin project to the mPFC, and serotonergic drugs influence emotion and cognition. Yet, the specific roles of endogenous serotonin release in the mPFC on neurophysiology and behavior are unknown. We show that axonal serotonin release in the mPFC directly inhibits the major mPFC output neurons. In serotonergic neurons projecting from the dorsal raphe to the mPFC, we find endogenous activity signatures pre-reward retrieval and at reward retrieval during a cognitive flexibility task. In vivo optogenetic activation of this pathway during pre-reward retrieval selectively improved extradimensional rule shift performance while inhibition impaired it, demonstrating sufficiency and necessity for mPFC serotonin release in cognitive flexibility. Locomotor activity and anxiety-like behavior were not affected by either optogenetic manipulation. Collectively, our data reveal a powerful and specific modulatory role of endogenous serotonin release from dorsal raphe-to-mPFC projecting neurons in cognitive flexibility.
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Premorbid performances determine the deleterious effects of nigrostriatal degeneration and pramipexole on behavioural flexibility. NPJ Parkinsons Dis 2023; 9:31. [PMID: 36859454 PMCID: PMC9977907 DOI: 10.1038/s41531-023-00475-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 02/14/2023] [Indexed: 03/03/2023] Open
Abstract
Subtle cognitive impairment can occur early in the course of Parkinson's disease (PD) and may manifest under different forms of executive dysfunction such as impaired cognitive flexibility. The precise contribution of nigrostriatal dopaminergic neurodegeneration to these non-motor features of the disease is poorly known. Whether such cognitive impairment associated with the disease process may also predate and contribute to the development of neuropsychiatric side-effects following dopamine replacement therapy remains largely unknown. To address these issues, we investigated the respective contributions of nigrostriatal degeneration and chronic treatment with the dopamine D3-preferring agonist pramipexole on behavioral flexibility in a rat model of PD. Flexible, intermediate and inflexible rats were identified based on baseline assessment of behavioral flexibility using an operant set-shifting task. Nigrostriatal degeneration was induced by bilateral viral-mediated expression of A53T mutated human α-synuclein in the substantia nigra pars compacta and behavioral flexibility was assessed after induction of nigrostriatal degeneration, and during chronic pramipexole treatment. Nigrostriatal degeneration impaired behavioral flexibility in flexible but not in inflexible rats. Pramipexole induced a decrease of behavioral flexibility that was exacerbated in lesioned rats and in the most flexible individuals. Furthermore, the deficits induced by pramipexole in lesioned rats affected different components of the task between flexible and inflexible individuals. This study demonstrates that nigrostriatal degeneration and pramipexole unequally impair behavioral flexibility, suggesting that the susceptibility to develop non-motor impairments upon treatment initiation could primarily depend on premorbid differences in behavioral flexibility.
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Torrado Pacheco A, Olson RJ, Garza G, Moghaddam B. Acute psilocybin enhances cognitive flexibility in rats. Neuropsychopharmacology 2023; 48:1011-1020. [PMID: 36807609 PMCID: PMC10209151 DOI: 10.1038/s41386-023-01545-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/22/2023]
Abstract
Psilocybin has been shown to improve symptoms of depression and anxiety when combined with psychotherapy or other clinician-guided interventions. To understand the neural basis for this pattern of clinical efficacy, experimental and conceptual approaches that are different than traditional laboratory models of anxiety and depression are needed. A potential novel mechanism is that acute psilocybin improves cognitive flexibility, which then enhances the impact of clinician-assisted interventions. Consistent with this idea, we find that acute psilocybin robustly improves cognitive flexibility in male and female rats using a task where animals switched between previously learned strategies in response to uncued changes in the environment. Psilocybin did not influence Pavlovian reversal learning, suggesting that its cognitive effects are selective to enhanced switching between previously learned behavioral strategies. The serotonin (5HT) 2 A receptor antagonist ketanserin blocked psilocybin's effect on set-shifting, while a 5HT2C-selective antagonist did not. Ketanserin alone also improved set-shifting performance, suggesting a complex relationship between psilocybin's pharmacology and its impact on flexibility. Further, the psychedelic drug 2,5-Dimethoxy-4-iodoamphetamine (DOI) impaired cognitive flexibility in the same task, suggesting that this effect of psilocybin does not generalize to all other serotonergic psychedelics. We conclude that the acute impact of psilocybin on cognitive flexibility provides a useful behavioral model to investigate its neuronal effects relevant to its positive clinical outcome.
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Affiliation(s)
- Alejandro Torrado Pacheco
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA.
| | - Randall J Olson
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Gabriela Garza
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Bita Moghaddam
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA.
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6
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Torrado Pacheco A, Olson RJ, Garza G, Moghaddam B. Acute psilocybin enhances cognitive flexibility in rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523291. [PMID: 36712091 PMCID: PMC9881983 DOI: 10.1101/2023.01.09.523291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Psilocybin has been shown to improve symptoms of depression and anxiety when combined with psychotherapy or other clinician-guided interventions. To understand the neural basis for this pattern of clinical efficacy, experimental and conceptual approaches that are different than traditional laboratory models of anxiety and depression are needed. A potential novel mechanism is that acute psilocybin improves cognitive flexibility, which then enhances the impact of clinician-assisted interventions. Consistent with this idea, we find that acute psilocybin robustly improves cognitive flexibility in male and female rats using a task where animals switched between previously learned strategies in response to uncued changes in the environment. Psilocybin did not influence Pavlovian reversal learning, suggesting that its cognitive effects are selective to enhanced switching between previously learned behavioral strategies. The serotonin (5HT) 2A receptor antagonist ketanserin blocked psilocybin's effect on set-shifting, while a 5HT2C-selective antagonist did not. Ketanserin alone also improved set-shifting performance, suggesting a complex relationship between psilocybin's pharmacology and its impact on flexibility. Further, the psychedelic drug 2,5-Dimethoxy-4-iodoamphetamine (DOI) impaired cognitive flexibility in the same task, suggesting that this effect of psilocybin does not generalize to all other serotonergic psychedelics. We conclude that the acute impact of psilocybin on cognitive flexibility provides a useful behavioral model to investigate its neuronal effects relevant to its positive clinical outcome.
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Affiliation(s)
- Alejandro Torrado Pacheco
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239,Corresponding author:;
| | - Randall J. Olson
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239
| | - Gabriela Garza
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239,Current address: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Bita Moghaddam
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239,Corresponding author:;
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Craine TJ, Race NS, Kutash LA, Iouchmanov AL, Moschonas EH, O'Neil DA, Sunleaf CR, Patel A, Patel N, Grobengeiser KO, Marshall IP, Magdelinic TN, Cheng JP, Bondi CO. Milnacipran Ameliorates Executive Function Impairments following Frontal Lobe Traumatic Brain Injury in Male Rats: A Multimodal Behavioral Assessment. J Neurotrauma 2023; 40:112-124. [PMID: 35979888 PMCID: PMC10024072 DOI: 10.1089/neu.2022.0289] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Traumatic brain injuries (TBIs) affect more than 10 million patients annually worldwide, causing long-term cognitive and psychosocial impairments. Frontal lobe TBIs commonly impair executive function, but laboratory models typically focus primarily on spatial learning and declarative memory. We implemented a multi-modal approach for clinically relevant cognitive-behavioral assessments of frontal lobe function in rats with TBI and assessed treatment benefits of the serotonin-norepinephrine reuptake inhibitor, milnacipran (MLN). Two attentional set-shifting tasks (AST) evaluated cognitive flexibility via the rats' ability to locate food-based rewards by learning, unlearning, and relearning sequential rule sets with shifting salient cues. Adult male rats reached stable pre-injury operant AST (oAST) performance in 3-4 weeks, then were isoflurane-anesthetized, subjected to a unilateral frontal lobe controlled cortical impact (2.4 mm depth, 4 m/sec velocity) or Sham injury, and randomized to treatment conditions. Milnacipran (30 mg/kg/day) or vehicle (VEH; 10% ethanol in saline) was administered intraperitoneally via implanted osmotic minipumps (continuous infusions post-surgery, 60 μL/h). Rats had a 10-day recovery post-TBI/Sham before performing light/location-based oAST for 10 days and, subsequently, odor/media-based digging AST (dAST) on the last test day (26-27 days post-injury) before sacrifice. Both AST tests revealed significant deficits in TBI+VEH rats, seen as elevated total trials and errors (p < 0.05), which generally normalized in MLN-treated rats (p < 0.05). This first simultaneous dual AST assessment demonstrates oAST and dAST are sufficiently sensitive and robust to detect subtle attentional and cognitive flexibility executive impairments after frontal lobe TBI in rats. Chronic MLN administration shows promise for attenuation of post-TBI executive function deficits, thus meriting further investigation.
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Affiliation(s)
- Timothy J. Craine
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- University of Bath, Claverton Down, Bath, United Kingdom
| | - Nicholas S. Race
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Association of Academic Physiatrists Rehabilitation Medicine Scientist Training Program, Owings Mills, Maryland, USA
| | - Lindsay A. Kutash
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anna L. Iouchmanov
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Eleni H. Moschonas
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Darik A. O'Neil
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Carlson R. Sunleaf
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Aarti Patel
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nima Patel
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Katherine O. Grobengeiser
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ian P. Marshall
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Taylor N. Magdelinic
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jeffrey P. Cheng
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Corina O. Bondi
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Neurobiology, and University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Children's Neuroscience Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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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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10
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Coeloglossum viride var. bracteatum extract attenuates staurosporine induced neurotoxicity by restoring the FGF2-PI3K/Akt signaling axis and Dnmt3. Heliyon 2021; 7:e07503. [PMID: 34401557 PMCID: PMC8353313 DOI: 10.1016/j.heliyon.2021.e07503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 05/03/2021] [Accepted: 07/03/2021] [Indexed: 01/04/2023] Open
Abstract
We previously demonstrated the antioxidant activity of Coeloglossum viride var. bracteatum extract (CE) in rat cortical neurons and in mice with chemically induced cognitive impairment. In this work, we established a staurosporine (STS)-induced toxicity model to decipher the neuroprotective mechanisms of CE. We found that CE protected cell viability and neurite integrity in STS-induced toxicity by restoring the levels of FGF2 and its associated PI3K/Akt signaling axis. LY294002, a pan-inhibitor of PI3K, antagonized the activity of CE, although its-mediated restoration of FGF2 was unaffected. In addition, CE restored levels of Bcl-2/Caspase-3, PKCα/CaM pathway, and Dnmt3a and Dnmt3b, two methyltransferases that contribute to de novo DNA methylation. The Dnmts inhibitor 5-azacytidine impaired CE-mediated restoration of Dnmt3 or CaM, as well as the transition of DNA methylation status on the Dnmt3 promoter. These results reveal potential mechanisms that could facilitate the study and application of CE as a neuroprotective agent.
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Lost in translation: no effect of repeated optogenetic cortico-striatal stimulation on compulsivity in rats. Transl Psychiatry 2021; 11:315. [PMID: 34031365 PMCID: PMC8144623 DOI: 10.1038/s41398-021-01448-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 04/30/2021] [Accepted: 05/11/2021] [Indexed: 11/30/2022] Open
Abstract
The orbitofrontal cortex-ventromedial striatum (OFC-VMS) circuitry is widely believed to drive compulsive behavior. Hyperactivating this pathway in inbred mice produces excessive and persistent self-grooming, which has been considered a model for human compulsivity. We aimed to replicate these findings in outbred rats, where there are few reliable compulsivity models. Male Long-Evans rats implanted with optical fibers into VMS and with opsins delivered into OFC received optical stimulation at parameters that produce OFC-VMS plasticity and compulsive grooming in mice. We then evaluated rats for compulsive self-grooming at six timepoints: before, during, immediately after, and 1 h after each stimulation, 1 and 2 weeks after the ending of a 6-day stimulation protocol. To further test for effects of OFC-VMS hyperstimulation, we ran animals in three standard compulsivity assays: marble burying, nestlet shredding, and operant attentional set-shifting. OFC-VMS stimulation did not increase self-grooming or induce significant changes in nestlet shredding, marble burying, or set-shifting in rats. Follow-on evoked potential studies verified that the stimulation protocol altered OFC-VMS synaptic weighting. In sum, although we induced physiological changes in the OFC-VMS circuitry, we could not reproduce in a strongly powered study in rats a model of compulsive behavior previously reported in mice. This suggests possible limitations to translation of mouse findings to species higher on the phylogenetic chain.
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12
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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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13
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Sullivan L, Shaffer H, Hill C, Del Arco A. Time-dependent changes in cognitive flexibility performance during intermittent social stress: Relevance for motivation and reward-seeking behavior. Behav Brain Res 2019; 370:111972. [PMID: 31128165 DOI: 10.1016/j.bbr.2019.111972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/06/2019] [Accepted: 05/21/2019] [Indexed: 12/21/2022]
Abstract
Repeated exposure to stress produces cognitive impairments that can lead to psychiatric disorders. How and when these cognitive impairments occur during repeated exposure to stress is not well understood. The present study investigates the time course effects of the exposure to intermittent episodes of social stress on cognitive flexibility performance. Male rats were trained to perform a cognitive flexibility (set-shifting) task. Then they were submitted to intermittent social defeat stress, which consisted of exposing animals to social defeat once every three days for ten days (four stress episodes). Set-shifting performance was evaluated before and in between social stress episodes, and up to ten days after the end of the stress protocol. Plasma levels of corticosterone after tail-pinch were also measured after the last set-shifting session. Intermittent exposure to social stress did not impair cognitive flexibility but produced short-and long-term changes in set-shifting performance. After the third social defeat episode, stressed animals required significantly more time to respond to cues (instrumental action) and to poke in the food-trough when no food pellet was delivered. These effects were reversed ten days after stress and suggest a decrease in motivation to pursue rewards. In contrast, stressed animals responded more accurately to light cues that predicted rewards. This effect, which emerged ten days after stress, suggests an increase in the reactivity to salient cues in the long-term. These time-dependent behavioral changes might help to understand the transition from social stress to stress-related disorders including drug abuse.
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Affiliation(s)
- Lauren Sullivan
- HSERM, School of Applied Sciences, University of Mississippi, Oxford, MS, USA
| | - Hannah Shaffer
- HSERM, School of Applied Sciences, University of Mississippi, Oxford, MS, USA
| | - Christopher Hill
- HSERM, School of Applied Sciences, University of Mississippi, Oxford, MS, USA
| | - Alberto Del Arco
- HSERM, School of Applied Sciences, University of Mississippi, Oxford, MS, USA; Department of Neurobiology and Anatomical Sciences, School of Medicine, University of Mississippi Medical Center, Jackson, MS, USA; Department of Biomolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS, USA.
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14
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Butkiewicz M, Rodriguez AL, Rainey SE, Wieting J, Luscombe VB, Stauffer SR, Lindsley CW, Conn PJ, Meiler J. Identification of Novel Allosteric Modulators of Metabotropic Glutamate Receptor Subtype 5 Acting at Site Distinct from 2-Methyl-6-(phenylethynyl)-pyridine Binding. ACS Chem Neurosci 2019; 10:3427-3436. [PMID: 31132237 DOI: 10.1021/acschemneuro.8b00227] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
As part of the G-protein coupled receptor (GPCR) family, metabotropic glutamate (mGlu) receptors play an important role as drug targets of cognitive diseases. Selective allosteric modulators of mGlu subtype 5 (mGlu5) have the potential to alleviate symptoms of numerous central nervous system disorders such as schizophrenia in a more targeted fashion. Multiple mGlu5 positive allosteric modulators (PAMs), such as 1-(3-fluorophenyl)-N-((3-fluorophenyl)-methylideneamino)-methanimine (DFB), 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)-benzamide (CDPPB), and 4-nitro-N-(1,3-diphenyl-1H-pyrazol-5-yl)-benzamide (VU-29), exert their actions by binding to a defined allosteric site on mGlu5 located in the seven-transmembrane domain (7TM) and shared by mGlu5 negative allosteric modulator (NAM) 2-methyl-6-(phenylethynyl)-pyridine (MPEP). Actions of the PAM N-{4-chloro-2-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]phenyl}-2-hydroxybenzamide (CPPHA) are mediated by a distinct allosteric site in the 7TM domain different from the MPEP binding site. Experimental evidence confirms these findings through mutagenesis experiments involving residues F585 (TM1) and A809 (TM7). In an effort to investigate mGlu5 PAM selectivity for this alternative allosteric site distinct from MPEP binding, we employed in silico quantitative structure-activity relationship (QSAR) modeling. Subsequent ligand-based virtual screening prioritized a set of 63 candidate compounds predicted from a library of over 4 million commercially available compounds to bind exclusively to this novel site. Experimental validation verified the biological activity for seven of 63 selected candidates. Further, medicinal chemistry optimizations based on these molecules revealed compound VU6003586 with an experimentally validated potency of 174 nM. Radioligand binding experiments showed only partial inhibition at very high concentrations, most likely indicative of binding at a non-MPEP site. Selective positive allosteric modulators for mGlu5 have the potential for tremendous impact concerning devastating neurological disorders such as schizophrenia and Huntington's disease. These identified and validated novel selective compounds can serve as starting points for more specifically tailored lead and probe molecules and thus help the development of potential therapeutic agents with reduced adverse effects.
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15
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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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16
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Zhou J, Wu B, Lin X, Dai Y, Li T, Zheng W, Guo W, Vakal S, Chen X, Chen JF. Accumbal Adenosine A 2A Receptors Enhance Cognitive Flexibility by Facilitating Strategy Shifting. Front Cell Neurosci 2019; 13:130. [PMID: 31031594 PMCID: PMC6470273 DOI: 10.3389/fncel.2019.00130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 03/14/2019] [Indexed: 12/16/2022] Open
Abstract
The deficits of cognitive flexibility (including attentional set-shifting and reversal learning) concomitant with dysfunction of the striatum are observed in several neuropsychiatric disorders. Rodent and human studies have identified the striatum [particularly the dorsomedial striatum (DMS) and nucleus accumbens (NAc)] as the critical locus for control of cognitive flexibility, but the effective neuromodulator and pharmacological control of cognitive flexibility remains to be determined. The adenosine A2A receptors (A2ARs) are highly enriched in the striatopallidal neurons where they integrate dopamine and glutamate signals to modulate several cognitive behaviors, but their contribution to cognitive flexibility control is unclear. In this study, by coupling an automated operant cognitive flexibility task with striatal subregional knockdown (KD) of the A2AR via the Cre-loxP strategy, we demonstrated that NAc A2AR KD improved cognitive flexibility with enhanced attentional set-shifting and reversal learning by decreasing regressive and perseverative errors, respectively. This facilitation was not attributed to mnemonic process or motor activity as NAc A2AR KD did not affect the visual discrimination, lever-pressing acquisition, and locomotor activity, but was associated with increased attention and motivation as evident by the progressive ratio test (PRT). In contrast to NAc A2ARs, DMS A2ARs KD neither affected visual discrimination nor improved set-shifting nor reversal learning, but promoted the effort-related motivation. Thus, NAc and DMS A2ARs exert dissociable controls of cognitive flexibility with NAc A2ARs KD selectively enhancing cognitive flexibility by facilitating strategy shifting with increased motivation/attention.
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Affiliation(s)
- Jianhong Zhou
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Beibei Wu
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Xiangxiang Lin
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Yuwei Dai
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Tingting Li
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Wu Zheng
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Wei Guo
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Sergii Vakal
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xingjun Chen
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Jiang-Fan Chen
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
- State Key Laboratory of Optometry & Vision Science, Wenzhou, China
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Cadinu D, Grayson B, Podda G, Harte MK, Doostdar N, Neill JC. NMDA receptor antagonist rodent models for cognition in schizophrenia and identification of novel drug treatments, an update. Neuropharmacology 2018; 142:41-62. [DOI: 10.1016/j.neuropharm.2017.11.045] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/28/2017] [Accepted: 11/27/2017] [Indexed: 01/05/2023]
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18
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Natividad LA, Steinman MQ, Laredo SA, Irimia C, Polis IY, Lintz R, Buczynski MW, Martin-Fardon R, Roberto M, Parsons LH. Phosphorylation of calcium/calmodulin-dependent protein kinase II in the rat dorsal medial prefrontal cortex is associated with alcohol-induced cognitive inflexibility. Addict Biol 2018; 23:1117-1129. [PMID: 28940879 PMCID: PMC5862723 DOI: 10.1111/adb.12568] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Repeated cycles of alcohol [ethanol (EtOH)] intoxication and withdrawal dysregulate excitatory glutamatergic systems in the brain and induce neuroadaptations in the medial prefrontal cortex (mPFC) that contribute to cognitive dysfunction. The mPFC is composed of subdivisions that are functionally distinct, with dorsal regions facilitating drug-cue associations and ventral regions modulating new learning in the absence of drug. A key modulator of glutamatergic activity is the holoenzyme calcium/calmodulin-dependent protein kinase II (CaMKII) that phosphorylates ionotropic glutamate receptors. Here, we examined the hypothesis that abstinence from chronic intermittent EtOH (CIE) exposure dysregulates CaMKII activity in the mPFC to impair cognitive flexibility. We used an operant model of strategy set shifting in male Long-Evans rats demonstrating reduced susceptibility to trial omissions during performance in a visual cue-guided task versus albino strains. Relative to naïve controls, rats experiencing approximately 10 days of abstinence from CIE vapor exposure demonstrated impaired performance during a procedural shift from visual cue to spatial location discrimination. Phosphorylation of CaMKII subtype α was upregulated in the dorsal, but not ventral mPFC of CIE-exposed rats, and was positively correlated with perseverative-like responding during the set shift. The findings suggest that abstinence from CIE exposure induces an undercurrent of kinase activity (e.g. CaMKII), which may promote aberrant glutamatergic responses in select regions of the mPFC. Given the role of the mPFC in modulating executive control of behavior, we propose that increased CaMKII subtype α activity reflects a dysregulated 'top-down' circuit that interferes with adaptive behavioral performance under changing environmental demands.
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Affiliation(s)
| | | | - Sarah A. Laredo
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Cristina Irimia
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Ilham Y. Polis
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Robert Lintz
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Matthew W. Buczynski
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Rémi Martin-Fardon
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Marisa Roberto
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, 92037, USA
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19
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MacQueen DA, Young JW, Cope ZA. Cognitive Phenotypes for Biomarker Identification in Mental Illness: Forward and Reverse Translation. Curr Top Behav Neurosci 2018; 40:111-166. [PMID: 29858983 DOI: 10.1007/7854_2018_50] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Psychiatric illness has been acknowledged for as long as people were able to describe behavioral abnormalities in the general population. In modern times, these descriptions have been codified and continuously updated into manuals by which clinicians can diagnose patients. None of these diagnostic manuals have attempted to tie abnormalities to neural dysfunction however, nor do they necessitate the quantification of cognitive function despite common knowledge of its ties to functional outcome. In fact, in recent years the National Institute of Mental Health released a novel transdiagnostic classification, the Research Domain Criteria (RDoC), which utilizes quantifiable behavioral abnormalities linked to neurophysiological processes. This reclassification highlights the utility of RDoC constructs as potential cognitive biomarkers of disease state. In addition, with RDoC and cognitive biomarkers, the onus of researchers utilizing animal models no longer necessitates the recreation of an entire disease state, but distinct processes. Here, we describe the utilization of constructs from the RDoC initiative to forward animal research on these cognitive and behavioral processes, agnostic of disease. By linking neural processes to these constructs, identifying putative abnormalities in diseased patients, more targeted therapeutics can be developed.
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Affiliation(s)
- David A MacQueen
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Jared W Young
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA.
| | - Zackary A Cope
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
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20
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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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21
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Neuroprotective effects of a Coeloglossum viride var. Bracteatum extract in vitro and in vivo. Sci Rep 2017; 7:9209. [PMID: 28835690 PMCID: PMC5569100 DOI: 10.1038/s41598-017-08957-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 07/20/2017] [Indexed: 12/02/2022] Open
Abstract
The excessive release and accumulation of glutamate in the brain is known to be associated with excitotoxicity. CE, an extract derived from the plant Coeloglossum viride var. Bracteatum, exerted neuroprotective effects against amyloid toxicity and oxidative stress in cortical neurons. The aims of this study are to examine whether CE also attenuates glutamate neurotoxicity in rat primary cultured cortical neurons and to determine the effect of CE in vivo. According to the results of MTT, LDH release, and TUNEL assays, the CE treatment significantly reduced glutamate-induced neurotoxicity in a dose-dependent manner. Moreover, the protective effects of CE were blocked by an Akt inhibitor, LY294002, suggesting that the PI3K/Akt signalling pathway is involved in the neuroprotective effects of CE. In addition, CE might regulate the PKC-GluA2 axis to prevent neuronal apoptosis. CE also protected against dopaminergic neuronal loss in a mouse model of MPTP-induced PD. Based on our results, CE exerted neuroprotective effects both in vitro and in vivo, thus providing a potential therapeutic target for the treatment or prevention of neurodegeneration.
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22
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Dauvermann MR, Lee G, Dawson N. Glutamatergic regulation of cognition and functional brain connectivity: insights from pharmacological, genetic and translational schizophrenia research. Br J Pharmacol 2017. [PMID: 28626937 DOI: 10.1111/bph.13919] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The pharmacological modulation of glutamatergic neurotransmission to improve cognitive function has been a focus of intensive research, particularly in relation to the cognitive deficits seen in schizophrenia. Despite this effort, there has been little success in the clinical use of glutamatergic compounds as procognitive drugs. Here, we review a selection of the drugs used to modulate glutamatergic signalling and how they impact on cognitive function in rodents and humans. We highlight how glutamatergic dysfunction, and NMDA receptor hypofunction in particular, is a key mechanism contributing to the cognitive deficits observed in schizophrenia and outline some of the glutamatergic targets that have been tested as putative procognitive targets for this disorder. Using translational research in this area as a leading exemplar, namely, models of NMDA receptor hypofunction, we discuss how the study of functional brain network connectivity can provide new insight into how the glutamatergic system impacts on cognitive function. Future studies characterizing functional brain network connectivity will increase our understanding of how glutamatergic compounds regulate cognition and could contribute to the future success of glutamatergic drug validation. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.
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Affiliation(s)
- Maria R Dauvermann
- School of Psychology, National University of Ireland, Galway, Ireland.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Graham Lee
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Neil Dawson
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, UK
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23
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Adaptive Encoding of Outcome Prediction by Prefrontal Cortex Ensembles Supports Behavioral Flexibility. J Neurosci 2017; 37:8363-8373. [PMID: 28729442 DOI: 10.1523/jneurosci.0450-17.2017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/02/2017] [Accepted: 06/09/2017] [Indexed: 11/21/2022] Open
Abstract
The prefrontal cortex (PFC) is thought to play a critical role in behavioral flexibility by monitoring action-outcome contingencies. How PFC ensembles represent shifts in behavior in response to changes in these contingencies remains unclear. We recorded single-unit activity and local field potentials in the dorsomedial PFC (dmPFC) of male rats during a set-shifting task that required them to update their behavior, among competing options, in response to changes in action-outcome contingencies. As behavior was updated, a subset of PFC ensembles encoded the current trial outcome before the outcome was presented. This novel outcome-prediction encoding was absent in a control task, in which actions were rewarded pseudorandomly, indicating that PFC neurons are not merely providing an expectancy signal. In both control and set-shifting tasks, dmPFC neurons displayed postoutcome discrimination activity, indicating that these neurons also monitor whether a behavior is successful in generating rewards. Gamma-power oscillatory activity increased before the outcome in both tasks but did not differentiate between expected outcomes, suggesting that this measure is not related to set-shifting behavior but reflects expectation of an outcome after action execution. These results demonstrate that PFC neurons support flexible rule-based action selection by predicting outcomes that follow a particular action.SIGNIFICANCE STATEMENT Tracking action-outcome contingencies and modifying behavior when those contingencies change is critical to behavioral flexibility. We find that ensembles of dorsomedial prefrontal cortex neurons differentiate between expected outcomes when action-outcome contingencies change. This predictive mode of signaling may be used to promote a new response strategy at the service of behavioral flexibility.
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24
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Istin M, Thiriet N, Solinas M. Behavioral flexibility predicts increased ability to resist excessive methamphetamine self-administration. Addict Biol 2017; 22:958-966. [PMID: 26969296 DOI: 10.1111/adb.12384] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 12/02/2015] [Accepted: 02/05/2016] [Indexed: 11/30/2022]
Abstract
Drug addiction is often associated with cognitive deficits and behavioral inflexibility that may contribute to the development and maintenance of addictive behaviors by reducing addicts' ability to control their behavior toward the drug. In this study, we investigated the relationships between pre-drug levels of behavioral flexibility and the risk to develop uncontrolled methamphetamine (METH) self-administration. First, we measured individual performance in an inter-dimensional set-shifting procedure in which animals have to switch between an external visual rule and an internal side rule in order to obtain food pellets. Then we allowed rats to self-administer METH for twenty long 14-hour sessions, and we investigated the relationships between behavioral flexibility and measures of control over drug intake. Rats rapidly acquired to self-administer high levels of METH which resulted in moderate weight loss. After several sessions of self-administration, whereas some rats progressively increased their METH intake, other rats showed very long voluntary pauses between drug injections and showed no escalation in METH self-administration. Interestingly, we found that behavioral flexibility is correlated with METH self-administration and that more flexible rats take less METH and do not escalate drug taking. These results suggest that traits of behavioral flexibility may protect against the development of excessive and dysregulated drug taking. Conversely, the inability to adapt behavioral responses as a function of the environmental contingencies may contribute to the risks to develop addiction to METH.
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Affiliation(s)
| | - Nathalie Thiriet
- University of Poitiers; France
- INSERM, U-1084; Experimental and Clinical Neurosciences Laboratory; France
| | - Marcello Solinas
- University of Poitiers; France
- INSERM, U-1084; Experimental and Clinical Neurosciences Laboratory; France
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25
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Zhao P, Zhou R, Zhu XY, Liu G, Zhao YP, Ma PS, Wu W, Niu Y, Sun T, Li YX, Yu JQ, Qian ZM. Neuroprotective Effects of Lycium barbarum Polysaccharide on Focal Cerebral Ischemic Injury in Mice. Neurochem Res 2017; 42:2798-2813. [PMID: 28508173 DOI: 10.1007/s11064-017-2293-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 03/04/2017] [Accepted: 05/06/2017] [Indexed: 01/05/2023]
Abstract
Increasing evidence demonstrates inflammation contributes to neuronal death following cerebral ischemia. Lycium barbarum polysaccharide (LBP) has been reported to prevent scopolamine-induced cognitive and memory deficits. We recently indicated that LBP exerts neuroprotective effect against focal cerebral ischemic injury in mice via attenuating the mitochondrial apoptosis pathway. The aim of this study was to investigate the neuroprotective effects of LBP against the behavioral dysfunction induced by focal cerebral ischemia injury in mice. Following 7 successive days of pretreatment with LBP (10, 20 and 40 mg/kg) and nimodipine (4 mg/kg) by intragastric gavage, mice were subjected to middle cerebral artery occlusion (MCAO). Following reperfusion, cerebral blood flows, the total power of the spontaneous EEG, and morphological changes were estimated. Learning and memory ability, and motor coordination were determined by Morris water maze task, rotarod and grip test. Western blot analysis, Real-Time fluorogenic PCR assays, and immunofluorescence staining were used to examine the expression of proinflammatory mediators and activation of microglia. The present study showed that LBP pretreatment significantly enhanced regional cortical blood flow and the total power of the spontaneous EEG, improved memory and motor coordination impairments, and inhibited over-activation of microglia and astrocytes after MCAO. Further study demonstrated LBP suppressed MCAO-induced activations of P65 NF-κB and P38 MAPK, and prevented up-regulations of proinflammatory mediators in hippocampus. Our data suggest that LBP can exert functional recovery of memory and motor coordination deficits and neuroprotective effect against cerebral ischemic injury in mice.
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Affiliation(s)
- Peng Zhao
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, 826 Zhang Heng Road, Pu Dong, Shanghai, 201203, China.,Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Ru Zhou
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Xiao-Yun Zhu
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Gang Liu
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Yu-Ping Zhao
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Peng-Sheng Ma
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Wei Wu
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China
| | - Yang Niu
- Key Laboratory of Hui Ethnic Medicine Modernization, Ministry of Education, Ningxia Medical University, Yinchuan, 750004, China
| | - Tao Sun
- Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Ningxia Medical University, Yinchuan, 750004, China
| | - Yu-Xiang Li
- College of Nursing, Ningxia Medical University, Yinchuan, 750004, China
| | - Jian-Qiang Yu
- Department of Pharmacology, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750004, Ningxia, China. .,Ningxia Hui Medicine Modern Engineering Research Center and Collaborative Innovation Center, Ningxia Medical University, Yinchuan, 750004, China.
| | - Zhong-Ming Qian
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, 826 Zhang Heng Road, Pu Dong, Shanghai, 201203, China. .,Department of Biochemistry, Institute for Nautical Medicine, Nantong University, Nantong, 226001, China.
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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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Jett JD, Bulin SE, Hatherall LC, McCartney CM, Morilak DA. Deficits in cognitive flexibility induced by chronic unpredictable stress are associated with impaired glutamate neurotransmission in the rat medial prefrontal cortex. Neuroscience 2017; 346:284-297. [PMID: 28131625 PMCID: PMC5344040 DOI: 10.1016/j.neuroscience.2017.01.017] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 12/21/2016] [Accepted: 01/10/2017] [Indexed: 12/25/2022]
Abstract
Deficits in cognitive flexibility, the ability to modify behavior in response to changes in the environment, contribute to the onset and maintenance of stress-related neuropsychiatric illnesses, such as depression. Cognitive flexibility depends on medial prefrontal cortex (mPFC) function, and in depressed patients, cognitive inflexibility is associated with hypoactivity and decreased glutamate receptor expression in the mPFC. Rats exposed to chronic unpredictable stress (CUS) exhibit compromised mPFC function on the extradimensional (ED) set-shifting task of the attentional set-shifting test. Moreover, CUS-induced ED deficits are associated with dendritic atrophy and decreased glutamate receptor expression in the mPFC. This evidence suggests that impaired glutamate signaling may underlie stress-induced deficits in cognitive flexibility. To test this hypothesis, we first demonstrated that blocking NMDA or AMPA receptors in the mPFC during ED replicated CUS-induced deficits in naïve rats. Secondly, we found that expression of activity-regulated cytoskeleton-associated protein (Arc) mRNA, a marker of behaviorally induced glutamate-mediated plasticity, was increased in the mPFC following ED. We then showed that CUS compromised excitatory afferent activation of the mPFC following pharmacological stimulation of the mediodorsal thalamus (MDT), indicated by a reduced induction of c-fos expression. Subsequently, in vivo recordings of evoked potentials in the mPFC indicated that CUS impaired afferent activation of the mPFC evoked by MDT stimulation, but not the ventral hippocampus. Lastly, glutamate microdialysis showed that CUS attenuated the acute stress-evoked increase in extracellular glutamate in the mPFC. Together, these results demonstrate that CUS-induced ED deficits are associated with compromised glutamate neurotransmission in the mPFC.
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Affiliation(s)
- Julianne D Jett
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Sarah E Bulin
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Lauren C Hatherall
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Carlie M McCartney
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - David A Morilak
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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28
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Siniscalchi MJ, Phoumthipphavong V, Ali F, Lozano M, Kwan AC. Fast and slow transitions in frontal ensemble activity during flexible sensorimotor behavior. Nat Neurosci 2016; 19:1234-42. [PMID: 27399844 PMCID: PMC5003707 DOI: 10.1038/nn.4342] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/16/2016] [Indexed: 12/12/2022]
Abstract
The ability to shift between repetitive and goal-directed actions is a hallmark of cognitive control. Previous studies have reported that adaptive shifts in behavior are accompanied by changes of neural activity in frontal cortex. However, neural and behavioral adaptations can occur at multiple time scales, and their relationship remains poorly defined. Here we developed an adaptive sensorimotor decision-making task for head-fixed mice, requiring them to shift flexibly between multiple auditory-motor mappings. Two-photon calcium imaging of secondary motor cortex (M2) revealed different ensemble activity states for each mapping. When adapting to a conditional mapping, transitions in ensemble activity were abrupt and occurred before the recovery of behavioral performance. By contrast, gradual and delayed transitions accompanied shifts toward repetitive responding. These results demonstrate distinct ensemble signatures associated with the start versus end of sensory-guided behavior and suggest that M2 leads in engaging goal-directed response strategies that require sensorimotor associations.
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Affiliation(s)
| | | | - Farhan Ali
- Department of Psychiatry, Yale University School of Medicine, New
Haven, Connecticut
| | - Marc Lozano
- Department of Psychiatry, Yale University School of Medicine, New
Haven, Connecticut
| | - Alex C. Kwan
- Interdepartmental Neuroscience Program, Yale University, New Haven,
Connecticut
- Department of Psychiatry, Yale University School of Medicine, New
Haven, Connecticut
- Department of Neuroscience, Yale University School of Medicine, New
Haven, Connecticut
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29
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Beas BS, Setlow B, Bizon JL. Effects of acute administration of the GABA(B) receptor agonist baclofen on behavioral flexibility in rats. Psychopharmacology (Berl) 2016; 233:2787-97. [PMID: 27256354 PMCID: PMC4919234 DOI: 10.1007/s00213-016-4321-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 05/09/2016] [Indexed: 12/20/2022]
Abstract
RATIONALE The ability to adjust response strategies when faced with changes in the environment is critical for normal adaptive behavior. Such behavioral flexibility is compromised by experimental disruption of cortical GABAergic signaling, as well as in conditions such as schizophrenia and normal aging that are characterized by cortical hyperexcitability. The current studies were designed to determine whether stimulation of GABAergic signaling using the GABA(B) receptor agonist baclofen can facilitate behavioral flexibility. METHODS Male Fischer 344 rats were trained in a set-shifting task in which they learned to discriminate between two response levers to obtain a food reward. Correct levers were signaled in accordance with two distinct response rules (rule 1: correct lever signaled by a cue light; rule 2: correct lever signaled by its left/right position). The order of rule presentation varied, but they were always presented sequentially, with the trials and errors to reach criterion performance on the second (set shift) rule providing the measure of behavioral flexibility. Experiments determined the effects of the GABA(B) receptor agonist baclofen (intraperitoneal, 0, 1.0, 2.5, and 4.0 mg/kg) administered acutely before the shift to the second rule. RESULTS Baclofen enhanced set-shifting performance. Control experiments demonstrated that this enhancement was not simply due to improved discrimination learning, nor was it due to impaired recall of the initial discrimination rule. CONCLUSIONS The results demonstrate that baclofen can facilitate behavioral flexibility, suggesting that GABA(B) receptor agonists may have utility for treating behavioral dysfunction in neuropsychiatric disorders.
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Affiliation(s)
- B. Sofia Beas
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL
| | - Barry Setlow
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL,Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL
| | - Jennifer L. Bizon
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL,Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL
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30
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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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31
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Park J, Wood J, Bondi C, Del Arco A, Moghaddam B. Anxiety Evokes Hypofrontality and Disrupts Rule-Relevant Encoding by Dorsomedial Prefrontal Cortex Neurons. J Neurosci 2016; 36:3322-35. [PMID: 26985040 PMCID: PMC4792942 DOI: 10.1523/jneurosci.4250-15.2016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/29/2016] [Accepted: 02/02/2016] [Indexed: 01/05/2023] Open
Abstract
Anxiety is a debilitating symptom of most psychiatric disorders, including major depression, post-traumatic stress disorder, schizophrenia, and addiction. A detrimental aspect of anxiety is disruption of prefrontal cortex (PFC)-mediated executive functions, such as flexible decision making. Here we sought to understand how anxiety modulates PFC neuronal encoding of flexible shifting between behavioral strategies. We used a clinically substantiated anxiogenic treatment to induce sustained anxiety in rats and recorded from dorsomedial PFC (dmPFC) and orbitofrontal cortex (OFC) neurons while they were freely moving in a home cage and while they performed a PFC-dependent task that required flexible switches between rules in two distinct perceptual dimensions. Anxiety elicited a sustained background "hypofrontality" in dmPFC and OFC by reducing the firing rate of spontaneously active neuronal subpopulations. During task performance, the impact of anxiety was subtle, but, consistent with human data, behavior was selectively impaired when previously correct conditions were presented as conflicting choices. This impairment was associated with reduced recruitment of dmPFC neurons that selectively represented task rules at the time of action. OFC rule representation was not affected by anxiety. These data indicate that a neural substrate of the decision-making deficits in anxiety is diminished dmPFC neuronal encoding of task rules during conflict-related actions. Given the translational relevance of the model used here, the data provide a neuronal encoding mechanism for how anxiety biases decision making when the choice involves overcoming a conflict. They also demonstrate that PFC encoding of actions, as opposed to cues or outcome, is especially vulnerable to anxiety. SIGNIFICANCE STATEMENT A debilitating aspect of anxiety is its impact on decision making and flexible control of behavior. These cognitive constructs depend on proper functioning of the prefrontal cortex (PFC). Understanding how anxiety affects PFC encoding of cognitive events is of great clinical and evolutionary significance. Using a clinically valid experimental model, we find that, under anxiety, decision making may be skewed by salient and conflicting environmental stimuli at the expense of flexible top-down guided choices. We also find that anxiety suppresses spontaneous activity of PFC neurons, and weakens encoding of task rules by dorsomedial PFC neurons. These data provide a neuronal encoding scheme for how anxiety disengages PFC during decision making.
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Affiliation(s)
- Junchol Park
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Jesse Wood
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Corina Bondi
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Alberto Del Arco
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Bita Moghaddam
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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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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Beas BS, McQuail JA, Ban Uelos C, Setlow B, Bizon JL. Prefrontal cortical GABAergic signaling and impaired behavioral flexibility in aged F344 rats. Neuroscience 2016; 345:274-286. [PMID: 26873002 DOI: 10.1016/j.neuroscience.2016.02.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/03/2016] [Accepted: 02/05/2016] [Indexed: 02/07/2023]
Abstract
The prefrontal cortex (PFC) is critical for the ability to flexibly adapt established patterns of behavior in response to a change in environmental contingencies. Impaired behavioral flexibility results in maladaptive strategies such as perseveration on response options that no longer produce a desired outcome. Pharmacological manipulations of prefrontal cortical GABAergic signaling modulate behavioral flexibility in animal models, and prefrontal cortical interneuron dysfunction is implicated in impaired behavioral flexibility that accompanies neuropsychiatric disease. As deficits in behavioral flexibility also emerge during the normal aging process, the goal of this study was to determine the role of GABAergic signaling, specifically via prefrontal cortical GABA(B) receptors, in such age-related deficits. Young and aged rats were trained in a set shifting task performed in operant chambers. First, rats learned to discriminate between two response levers to obtain a food reward on the basis of a cue light illuminated above the correct lever. Upon acquisition of this initial discrimination, the contingencies were shifted such that rats had to ignore the cue light and respond on the levers according to their left/right positions. Both young and aged rats acquired the initial discrimination similarly; however, aged rats were impaired relative to young following the set shift. Among aged rats, GABA(B) receptor expression in the medial prefrontal cortex (mPFC) was strongly correlated with set shifting, such that lower expression was associated with worse performance. Subsequent experiments showed that intra-mPFC administration of the GABA(B) receptor agonist baclofen enhanced set shifting performance in aged rats. These data directly link GABAergic signaling via GABA(B) receptors to impaired behavioral flexibility associated with normal aging.
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Affiliation(s)
- B S Beas
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States.
| | - J A McQuail
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States.
| | - C Ban Uelos
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States.
| | - B Setlow
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States; Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL, United States; Department of Psychology, University of Florida, Gainesville, FL, United States.
| | - J L Bizon
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States; Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL, United States.
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Neurophysiology of rule switching in the corticostriatal circuit. Neuroscience 2016; 345:64-76. [PMID: 26851774 DOI: 10.1016/j.neuroscience.2016.01.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/12/2016] [Accepted: 01/28/2016] [Indexed: 01/06/2023]
Abstract
The ability to adjust behavioral responses to cues in a changing environment is crucial for survival. Activity in the medial Prefrontal Cortex (mPFC) is thought to both represent rules to guide behavior as well as detect and resolve conflicts between rules in changing contingencies. While lesion and pharmacological studies have supported a crucial role for mPFC in this type of set-shifting, an understanding of how mPFC represents current rules or detects and resolves conflict between different rules is still unclear. Meanwhile, medial dorsal striatum (mDS) receives major projections from mPFC and neural activity of mDS is closely linked to action selection, making the mDS a potential major player for enacting rule-guided action policies. However, exactly what is signaled by mPFC and how this impacts neural signals in mDS is not well known. In this review, we will summarize what is known about neural signals of rules and set shifting in both prefrontal cortex and dorsal striatum, as well as provide questions and directions for future experiments.
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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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NMDA and dopamine D1 receptors within NAc-shell regulate IEG proteins expression in reward circuit during cocaine memory reconsolidation. Neuroscience 2015; 315:45-69. [PMID: 26674058 DOI: 10.1016/j.neuroscience.2015.11.063] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/03/2015] [Accepted: 11/29/2015] [Indexed: 01/11/2023]
Abstract
Reactivation of consolidated memory initiates a memory reconsolidation process, during which the reactivated memory is susceptible to strengthening, weakening or updating. Therefore, effective interference with the memory reconsolidation process is expected to be an important treatment for drug addiction. The nucleus accumbens (NAc) has been well recognized as a pathway component that can prevent drug relapse, although the mechanism underlying this function is poorly understood. We aimed to clarify the regulatory role of the NAc in the cocaine memory reconsolidation process, by examining the effect of applying different pharmacological interventions to the NAc on Zif 268 and Fos B expression in the entire reward circuit after cocaine memory reactivation. Through the cocaine-induced conditioned place preference (CPP) model, immunohistochemical and immunofluorescence staining for Zif 268 and Fos B were used to explore the functional activated brain nuclei after cocaine memory reactivation. Our results showed that the expression of Zif 268 and Fos B was commonly increased in the medial prefrontal cortex (mPFC), the infralimbic cortex (IL), the NAc-core, the NAc-shell, the hippocampus (CA1, CA2, and CA3 subregions), the amygdala, the ventral tegmental area (VTA), and the supramammillary nucleus (SuM) following memory reconsolidation, and Zif 268/Fos B co-expression was commonly observed (for Zif 268: 51-68%; for Fos B: 52-66%). Further, bilateral NAc-shell infusion of MK 801 and SCH 23390, but not raclopride or propranolol, prior to addictive memory reconsolidation, decreased Zif 268 and Fos B expression in the entire reward circuit, except for the amygdala, and effectively disturbed subsequent CPP-related behavior. In summary, N-methyl-d-aspartate (NMDA) and dopamine D1 receptors, but not dopamine D2 or β adrenergic receptors, within the NAc-shell, may regulate Zif 268 and Fos B expression in most brain nuclei of the reward circuit after cocaine memory reactivation. These findings indicated that the NAc played a key role in regulating addictive memory reconsolidation by influencing the function of the entire addictive memory network.
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Wierońska JM, Zorn SH, Doller D, Pilc A. Metabotropic glutamate receptors as targets for new antipsychotic drugs: Historical perspective and critical comparative assessment. Pharmacol Ther 2015; 157:10-27. [PMID: 26549541 DOI: 10.1016/j.pharmthera.2015.10.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this review, we aim to present, discuss and clarify our current understanding regarding the prediction of possible antipsychotic effects of metabotropic glutamate (mGlu) receptor ligands. The number of preclinical trials clearly indicates, that this group of compounds constitutes an excellent alternative to presently used antipsychotic therapy, being effective not only to positive, but also negative and cognitive symptoms of schizophrenia. Although the results of clinical trials that were performed for the group of mGlu2/3 agonists were not so enthusiastic as in animal studies, they still showed that mGlu ligands do not induced variety of side effects typical for presently used antipsychotics, and were generally well tolerated. The lack of satisfactory effectiveness towards schizophrenia symptoms of mGlu2/3 activators in humans could be a result of variety of uncontrolled factors and unidentified biomarkers different for each schizophrenia patient, that should be taken into consideration in the future set of clinical trials. The subject is still open for further research, and the novel classes of mGlu5 or mGlu2/3 agonists/PAMs were recently introduced, including the large group of compounds from the third group of mGlu receptors, especially of mGlu4 subtype. Finally, more precise treatment based on simultaneous administration of minimal doses of the ligands for two or more receptors, seems to be promising in the context of symptoms-specific schizophrenia treatment.
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Affiliation(s)
- Joanna M Wierońska
- Institute of Pharmacology, Polish Academy of Sciences, 31-343 Krakow, Poland
| | | | | | - Andrzej Pilc
- Institute of Pharmacology, Polish Academy of Sciences, 31-343 Krakow, Poland.
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Totah NK, Logothetis NK, Eschenko O. Atomoxetine accelerates attentional set shifting without affecting learning rate in the rat. Psychopharmacology (Berl) 2015. [PMID: 26202614 DOI: 10.1007/s00213-015-4028-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
RATIONALE Shifting to a new rule is a form of behavioral flexibility that is impaired in numerous psychiatric and neurological illnesses. Animal studies have revealed that this form of flexibility depends upon norepinephrine (NE) neurotransmission. Atomoxetine, a NE reuptake inhibitor, improves performance of humans in set shifting tasks. OBJECTIVE Our objective was to validate its effects in a rodent set shifting task. METHODS We tested the drug effect using an operant task that required a shift from a visual cue-guided behavior to a novel location-guided rule. RESULTS A 1.0-mg/kg dose significantly accelerated rule shifting without affecting learning strategies, such as win-stay or lose-shift. Fitting behavioral performance with a learning function provided a measure of learning rate. CONCLUSION This novel analysis revealed that atomoxetine accelerated shifting to the new rule without affecting learning rate.
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Affiliation(s)
- Nelson K Totah
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Spemannstr. 38, 72076, Tuebingen, Germany,
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mGlu5-GABAB interplay in animal models of positive, negative and cognitive symptoms of schizophrenia. Neurochem Int 2015; 88:97-109. [DOI: 10.1016/j.neuint.2015.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 03/17/2015] [Accepted: 03/23/2015] [Indexed: 11/19/2022]
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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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Biased mGlu5-Positive Allosteric Modulators Provide In Vivo Efficacy without Potentiating mGlu5 Modulation of NMDAR Currents. Neuron 2015; 86:1029-1040. [PMID: 25937172 DOI: 10.1016/j.neuron.2015.03.063] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 02/22/2015] [Accepted: 03/24/2015] [Indexed: 12/14/2022]
Abstract
Schizophrenia is associated with disruptions in N-methyl-D-aspartate glutamate receptor subtype (NMDAR)-mediated excitatory synaptic signaling. The metabotropic glutamate receptor subtype 5 (mGlu5) is a closely associated signaling partner with NMDARs and regulates NMDAR function in forebrain regions implicated in the pathology of schizophrenia. Efficacy of mGlu5 positive allosteric modulators (PAMs) in animal models of psychosis and cognition was previously attributed to potentiation of NMDAR function. To directly test this hypothesis, we identified VU0409551 as a novel mGlu5 PAM that exhibits distinct stimulus bias and selectively potentiates mGlu5 coupling to Gαq-mediated signaling but not mGlu5 modulation of NMDAR currents or NMDAR-dependent synaptic plasticity in the rat hippocampus. Interestingly, VU0409551 produced robust antipsychotic-like and cognition-enhancing activity in animal models. These data provide surprising new mechanistic insights into the actions of mGlu5 PAMs and suggest that modulation of NMDAR currents is not critical for in vivo efficacy. VIDEO ABSTRACT.
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Lim BV, Shin MS, Lee JM, Seo JH. Treadmill exercise prevents GABAergic neuronal loss with suppression of neuronal activation in the pilocarpine-induced epileptic rats. J Exerc Rehabil 2015; 11:80-6. [PMID: 25960980 PMCID: PMC4415754 DOI: 10.12965/jer.150193] [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: 03/22/2015] [Accepted: 04/08/2015] [Indexed: 12/17/2022] Open
Abstract
Epilepsy is a common neurological disorder characterized by seizure and loss of neuronal cells by abnormal rhythmic firing of neurons in the brain. In the present study, we investigated the effect of treadmill exercise on gamma-aminobutyric acid (GABA)ergic neuronal loss in relation with neuronal activation using pilocarpine-induced epileptic rats. The rats were divided into four groups: control group, control and treadmill exercise group, pilocarpine-induced epilepsy group, and pilocarpine-induced epilepsy and treadmill exercise group. Epilepsy was induced by intraperitoneal injection of 320 mg/kg pilocarpine hydrochloride. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 2 weeks. In the present results, neuronal loss in the hippocampal CA1 region was increased after pilocarpine-induced seizure. Treadmill exercise inhibited hippocampal neuronal loss in the epileptic rats. Glutamic acid decarboxylase (GAD67) expression in the hippocampal CA1 region was reduced by pilocarpine-induced seizure. Treadmill exercise increased GAD67 expression in the epileptic rats. c-Fos expression in the hippocampal CA1 region was increased in response to epileptic seizure. Treadmill exercise inhibited c-Fos expression in the epileptic rats. Epileptic seizure increased brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) expressions in the hippocampus. Treadmill exercise suppressed BDNF and TrkB expressions in the epileptic rats. In the present study, treadmill exercise prevented GABAergic neuronal loss and inhibited neuronal activation in the hippocampal CA1 region through the down-regulation of BDNF-TrkB signaling pathway.
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Affiliation(s)
- Baek-Vin Lim
- Department of Exercise Prescription, Division of Leisure & Sports Science, Dongseo University, Busan, Korea
| | - Mal-Soon Shin
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Jae-Min Lee
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Jin-Hee Seo
- Division of Sports Science, Baekseok University, Cheonan, Korea
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Martín-Martín ML, Bartolomé-Nebreda JM, Conde-Ceide S, Alonso de Diego SA, López S, Martínez-Viturro CM, Tong HM, Lavreysen H, Macdonald GJ, Steckler T, Mackie C, Bridges TM, Daniels JS, Niswender CM, Noetzel MJ, Jones CK, Conn PJ, Lindsley CW, Stauffer SR. Discovery and SAR of novel series of imidazopyrimidinones and dihydroimidazopyrimidinones as positive allosteric modulators of the metabotropic glutamate receptor 5 (mGlu5). Bioorg Med Chem Lett 2015; 25:1310-7. [PMID: 25683622 DOI: 10.1016/j.bmcl.2015.01.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 10/24/2022]
Abstract
We report the discovery and SAR of two novel series of imidazopyrimidinones and dihydroimidazopyrimidinones as metabotropic glutamate receptor 5 (mGlu5) positive allosteric modulators (PAMs). Exploration of several structural features in the western and eastern part of the imidazopyrimidinone core and combinations thereof, revealed compound 4a as a mGlu5 PAM with good in vitro potency and efficacy, acceptable drug metabolism and pharmacokinetic (DMPK) properties and in vivo efficacy in an amphetamine-based model of psychosis. However, the presence of CNS-mediated adverse effects in preclinical species precluded any further in vivo evaluation.
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Affiliation(s)
- María Luz Martín-Martín
- Neuroscience Medicinal Chemistry, Janssen Research and Development, Jarama 75A, 45007 Toledo, Spain.
| | | | - Susana Conde-Ceide
- Neuroscience Medicinal Chemistry, Janssen Research and Development, Jarama 75A, 45007 Toledo, Spain
| | - Sergio A Alonso de Diego
- Neuroscience Medicinal Chemistry, Janssen Research and Development, Jarama 75A, 45007 Toledo, Spain
| | - Silvia López
- Neuroscience Medicinal Chemistry, Janssen Research and Development, Jarama 75A, 45007 Toledo, Spain
| | | | - Han Min Tong
- Neuroscience Medicinal Chemistry, Janssen Research and Development, Jarama 75A, 45007 Toledo, Spain
| | - Hilde Lavreysen
- Neuroscience, Janssen Research and Development, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Gregor J Macdonald
- Neuroscience, Janssen Research and Development, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Thomas Steckler
- Neuroscience, Janssen Research and Development, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Claire Mackie
- Discovery Sciences ADME/Tox, Janssen Research and Development, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Thomas M Bridges
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - J Scott Daniels
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Meredith J Noetzel
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Carrie K Jones
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Shaun R Stauffer
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
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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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Opportunities and challenges in the discovery of allosteric modulators of GPCRs for treating CNS disorders. Nat Rev Drug Discov 2014; 13:692-708. [PMID: 25176435 DOI: 10.1038/nrd4308] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Novel allosteric modulators of G protein-coupled receptors (GPCRs) are providing fundamental advances in the development of GPCR ligands with high subtype selectivity and novel modes of efficacy that have not been possible with traditional approaches. As new allosteric modulators are advancing as drug candidates, we are developing an increased understanding of the major advantages and broad range of activities that can be achieved with these agents through selective modulation of specific signalling pathways, differential effects on GPCR homodimers versus heterodimers, and other properties. This understanding creates exciting opportunities, as well as unique challenges, in the optimization of novel therapeutic agents for disorders of the central nervous system.
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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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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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Knockdown of prodynorphin gene prevents cognitive decline, reduces anxiety, and rescues loss of group 1 metabotropic glutamate receptor function in aging. J Neurosci 2013; 33:12792-804. [PMID: 23904614 DOI: 10.1523/jneurosci.0290-13.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Expression of dynorphin, an endogenous opioid peptide, increases with age and has been associated with memory impairments in rats. In human, prodynorphin (Pdyn) gene polymorphisms might be linked to cognitive function in the elderly. Moreover, elevated dynorphin levels have been reported in postmortem samples from Alzheimer's disease patients. However, the cellular and molecular processes affected by higher dynorphin levels during aging remain unknown. Using Pdyn(-/-) mice, we observed significant changes in the function and expression of Group 1 metabotropic glutamate receptor (mGluR). Compared with age-matched wild-type (WT) littermates, we found increased expression of mGluR1α and mGluR5 in the hippocampus and cortex of old, but not young, Pdyn(-/-) mice. Increased Group 1 mGluR expression in aged Pdyn(-/-) mice was associated with enhanced mGluR-mediated long-term depression, a form of synaptic plasticity. Notably, whereas aged WT mice developed spatial and recognition memory deficits, aged Pdyn(-/-) mice performed similarly as young mice. Pharmacological treatments with 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide, a positive modulator of mGlu5 receptors, or norbinaltorphimine, an antagonist for dynorphin-targeted κ-opioid receptor, rescued memory in old WT mice. Conversely, mGlu5 receptor antagonist 2-methyl-6-(phenylethynyl)pyridine hydrochloride impaired spatial memory of old Pdyn(-/-) mice. Intact cognition in aged Pdyn(-/-) mice paralleled with increased expression of Group 1 mGluR-related genes Homer 1a and Arc. Finally, aged Pdyn(-/-) mice displayed less anxiety-related behaviors than age-matched WT mice. Together, our results suggest that elevated Pdyn expression during normal aging reduces mGluR expression and signaling, which in turn impairs cognitive functions and increases anxiety.
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49
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Blobaum AL, Bridges TM, Byers FW, Turlington ML, Mattmann ME, Morrison RD, Mackie C, Lavreysen H, Bartolomé JM, Macdonald GJ, Steckler T, Jones CK, Niswender CM, Conn PJ, Lindsley CW, Stauffer SR, Daniels JS. Heterotropic activation of the midazolam hydroxylase activity of CYP3A by a positive allosteric modulator of mGlu5: in vitro to in vivo translation and potential impact on clinically relevant drug-drug interactions. Drug Metab Dispos 2013; 41:2066-75. [PMID: 24003250 DOI: 10.1124/dmd.113.052662] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Allosteric modulation of G protein-coupled receptors has gained considerable attention in the drug discovery arena because it opens avenues to achieve greater selectivity over orthosteric ligands. We recently identified a series of positive allosteric modulators (PAMs) of metabotropic glutamate receptor 5 (mGlu(5)) for the treatment of schizophrenia that exhibited robust heterotropic activation of CYP3A4 enzymatic activity. The prototypical compound from this series, 5-(4-fluorobenzyl)-2-((3-fluorophenoxy)methyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine (VU0448187), was found to activate CYP3A4 to >100% of its baseline intrinsic midazolam (MDZ) hydroxylase activity in vitro; activation was CYP3A substrate specific and mGlu(5) PAM dependent. Additional studies revealed the concentration-dependence of CYP3A activation by VU0448187 in multispecies hepatic and intestinal microsomes and hepatocytes, as well as a diminished effect observed in the presence of ketoconazole. Kinetic analyses of the effect of VU0448187 on MDZ metabolism in recombinant P450 or human liver microsomes resulted in a significant increase in V(max) (minimal change in K(m)) and required the presence of cytochrome b5. The atypical kinetics translated in vivo, as rats receiving an intraperitoneal administration of VU0448187 prior to MDZ treatment demonstrated a significant increase in circulating 1- and 4-hydroxy- midazolam (1-OH-MDZ, 4-OH-MDZ) levels compared with rats administered MDZ alone. The discovery of a potent substrate-selective activator of rodent CYP3A with an in vitro to in vivo translation serves to illuminate the impact of increasing intrinsic enzymatic activity of hepatic and extrahepatic CYP3A in rodents, and presents the basis to build models capable of framing the clinical relevance of substrate-dependent heterotropic activation.
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Affiliation(s)
- Anna L Blobaum
- Drug Metabolism and Pharmacokinetics Laboratory (A.L.B., T.M.B., F.W.B., R.D.M., J.S.D.), Medicinal Chemistry Laboratory (M.L.T., M.E.M., C.W.L., S.R.S.), and Molecular Pharmacology Laboratory (C.K.J., C.M.N., P.J.C.), Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee; CREATe ADME/Tox, (C.M.), and Neuroscience (H.L., G.J.M., T.S.), Janssen Research and Development, Beerse, Belgium; and Jarama 75, Toledo, Spain (J.M.B.)
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50
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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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