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Eapen AV, Fernández-Fernández D, Georgiou J, Bortolotto ZA, Lightman S, Jane DE, Volianskis A, Collingridge GL. Multiple roles of GluN2D-containing NMDA receptors in short-term potentiation and long-term potentiation in mouse hippocampal slices. Neuropharmacology 2021; 201:108833. [PMID: 34637787 PMCID: PMC8607330 DOI: 10.1016/j.neuropharm.2021.108833] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/28/2021] [Accepted: 10/07/2021] [Indexed: 01/07/2023]
Abstract
The GluN2 subunits of N-methyl-d-aspartate receptors (NMDARs) are key drivers of synaptic plasticity in the brain, where the particular GluN2 composition endows the NMDAR complex with distinct pharmacological and physiological properties. Compared to GluN2A and GluN2B subunits, far less is known about the role of the GluN2D subunit in synaptic plasticity. In this study, we have used a GluN2C/2D selective competitive antagonist, UBP145, in combination with a GluN2D global knockout (GluN2D KO) mouse line to study the contribution of GluN2D-containing NMDARs to short-term potentiation (STP) and long-term potentiation (LTP) in the CA1 region of mouse hippocampal slices. We made several distinct observations: First, GluN2D KO mice have higher levels of LTP compared to wild-type (WT) mice, an effect that was occluded by blockade of GABA receptor-mediated inhibition or by using a strong LTP induction protocol. Second, UBP145 partially inhibited LTP in WT but not GluN2D KO mice. Third, UBP145 inhibited a component of STP, termed STP2, in WT but not GluN2D KO mice. Taken together, these findings suggest an involvement for GluN2D-containing NMDARs in both STP and LTP in mouse hippocampus.
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Affiliation(s)
- Alen V Eapen
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada.
| | - Diego Fernández-Fernández
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
| | - Zuner A Bortolotto
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | | | - David E Jane
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Arturas Volianskis
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK; Bristol Medical School, University of Bristol, Bristol, UK; Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Graham L Collingridge
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
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2
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Palacios-Filardo J, Udakis M, Brown GA, Tehan BG, Congreve MS, Nathan PJ, Brown AJH, Mellor JR. Acetylcholine prioritises direct synaptic inputs from entorhinal cortex to CA1 by differential modulation of feedforward inhibitory circuits. Nat Commun 2021; 12:5475. [PMID: 34531380 PMCID: PMC8445995 DOI: 10.1038/s41467-021-25280-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/21/2021] [Indexed: 02/08/2023] Open
Abstract
Acetylcholine release in the hippocampus plays a central role in the formation of new memory representations. An influential but largely untested theory proposes that memory formation requires acetylcholine to enhance responses in CA1 to new sensory information from entorhinal cortex whilst depressing inputs from previously encoded representations in CA3. Here, we show that excitatory inputs from entorhinal cortex and CA3 are depressed equally by synaptic release of acetylcholine in CA1. However, feedforward inhibition from entorhinal cortex exhibits greater depression than CA3 resulting in a selective enhancement of excitatory-inhibitory balance and CA1 activation by entorhinal inputs. Entorhinal and CA3 pathways engage different feedforward interneuron subpopulations and cholinergic modulation of presynaptic function is mediated differentially by muscarinic M3 and M4 receptors, respectively. Thus, our data support a role and mechanisms for acetylcholine to prioritise novel information inputs to CA1 during memory formation.
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Affiliation(s)
- Jon Palacios-Filardo
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK
| | - Matt Udakis
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK
| | - Giles A Brown
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
- OMass Therapeutics Ltd, The Schrödinger Building, Oxford, UK
| | - Benjamin G Tehan
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
- OMass Therapeutics Ltd, The Schrödinger Building, Oxford, UK
| | - Miles S Congreve
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
| | - Pradeep J Nathan
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Alastair J H Brown
- Sosei Heptares, Steinmetz Building, Granta Park, Great Abingdon, Cambridge, UK
| | - Jack R Mellor
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK.
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3
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Copeland CS, Neale SA, Nisenbaum ES, Salt TE. Group II metabotropic glutamate receptor (mGlu 2 and mGlu 3 ) roles in thalamic processing. Br J Pharmacol 2021; 179:1607-1619. [PMID: 34355803 DOI: 10.1111/bph.15640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 06/02/2021] [Accepted: 07/12/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE As the thalamus underpins almost all aspects of behaviour, it is important to understand how the thalamus operates. Group II metabotropic glutamate (mGlu2 /mGlu3 ) receptor activation reduces inhibition in thalamic nuclei originating from the surrounding thalamic reticular nucleus (TRN). Whilst an mGlu2 component to this effect has been reported, in this study, we demonstrate that it is likely, largely mediated via mGlu3 . EXPERIMENTAL APPROACH The somatosensory ventrobasal thalamus (VB) is an established model for probing fundamental principles of thalamic function. In vitro slices conserving VB-TRN circuitry from wild-type and mGlu3 knockout mouse brains were used to record IPSPs and mIPSCs. In vivo extracellular recordings were made from VB neurons in anaesthetised rats. A range of selective pharmacological agents were used to probe Group II mGlu receptor function (agonist, LY354740; antagonist, LY341495; mGlu2 positive allosteric modulator, LY487379 and mixed mGlu2 agonist/mGlu3 antagonist LY395756). KEY RESULTS The in vitro and in vivo data are complementary and suggest that mGlu3 receptor activation is largely responsible for potentiating responses to somatosensory stimulation by reducing inhibition from the TRN. CONCLUSIONS AND IMPLICATIONS mGlu3 receptor activation in the VB likely enables important somatosensory information to be discerned from background activity. These mGlu3 receptors are likely to be endogenously activated via 'glutamate spillover'. In cognitive thalamic nuclei, this mechanism may be of importance in governing attentional processes. Positive allosteric modulation of endogenous mGlu3 receptor activation may therefore enhance cognitive function in pathophysiological disease states, such as schizophrenia, thus representing a highly specific therapeutic target.
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Affiliation(s)
- Caroline S Copeland
- Institute of Pharmaceutical Sciences, King's College London, London, UK.,Institute of Ophthalmology, University College London, London, UK
| | | | - Eric S Nisenbaum
- Pain/Migraine Research Group, Eli Lilly and Company, Indianapolis, Indiana, USA
| | - Thomas E Salt
- Institute of Ophthalmology, University College London, London, UK.,Neurexpert Limited, The Core, Newcastle upon Tyne, UK
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4
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Johnson KA, Lovinger DM. Allosteric modulation of metabotropic glutamate receptors in alcohol use disorder: Insights from preclinical investigations. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 88:193-232. [PMID: 32416868 DOI: 10.1016/bs.apha.2020.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are family C G protein-coupled receptors (GPCRs) that modulate neuronal excitability and synaptic transmission throughout the nervous system. Owing to recent advances in development of subtype-selective allosteric modulators of mGlu receptors, individual members of the mGlu receptor family have been proposed as targets for treating a variety of neurological and psychiatric disorders, including substance use disorders. In this chapter, we highlight preclinical evidence that allosteric modulators of mGlu receptors could be useful for reducing alcohol consumption and preventing relapse in alcohol use disorder (AUD). We begin with an overview of the preclinical models that are used to study mGlu receptor involvement in alcohol-related behaviors. Alcohol exposure causes adaptations in both expression and function of various mGlu receptor subtypes, and pharmacotherapies aimed at reversing these adaptations have the potential to reduce alcohol consumption and seeking. Positive allosteric modulators (PAMs) of mGlu2 and negative allosteric modulators of mGlu5 show particular promise for reducing alcohol intake and/or preventing relapse. Finally, this chapter discusses important considerations for translating preclinical findings toward the development of clinically useful drugs, including the potential for PAMs to avoid tolerance issues that are frequently observed with repeated administration of GPCR agonists.
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Affiliation(s)
- Kari A Johnson
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
| | - David M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, US National Institutes of Health, Rockville, MD, United States
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5
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Monn JA, Henry SS, Massey SM, Clawson DK, Chen Q, Diseroad BA, Bhardwaj RM, Atwell S, Lu F, Wang J, Russell M, Heinz BA, Wang XS, Carter JH, Getman BG, Adragni K, Broad LM, Sanger HE, Ursu D, Catlow JT, Swanson S, Johnson BG, Shaw DB, McKinzie DL, Hao J. Synthesis and Pharmacological Characterization of C4 β-Amide-Substituted 2-Aminobicyclo[3.1.0]hexane-2,6-dicarboxylates. Identification of (1 S,2 S,4 S,5 R,6 S)-2-Amino-4-[(3-methoxybenzoyl)amino]bicyclo[3.1.0]hexane-2,6-dicarboxylic Acid (LY2794193), a Highly Potent and Selective mGlu 3 Receptor Agonist. J Med Chem 2018; 61:2303-2328. [PMID: 29350927 DOI: 10.1021/acs.jmedchem.7b01481] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Multiple therapeutic opportunities have been suggested for compounds capable of selective activation of metabotropic glutamate 3 (mGlu3) receptors, but small molecule tools are lacking. As part of our ongoing efforts to identify potent, selective, and systemically bioavailable agonists for mGlu2 and mGlu3 receptor subtypes, a series of C4β-N-linked variants of (1 S,2 S,5 R,6 S)-2-amino-bicyclo[3.1.0]hexane-2,6-dicarboxylic acid 1 (LY354740) were prepared and evaluated for both mGlu2 and mGlu3 receptor binding affinity and functional cellular responses. From this investigation we identified (1 S,2 S,4 S,5 R,6 S)-2-amino-4-[(3-methoxybenzoyl)amino]bicyclo[3.1.0]hexane-2,6-dicarboxylic acid 8p (LY2794193), a molecule that demonstrates remarkable mGlu3 receptor selectivity. Crystallization of 8p with the amino terminal domain of hmGlu3 revealed critical binding interactions for this ligand with residues adjacent to the glutamate binding site, while pharmacokinetic assessment of 8p combined with its effect in an mGlu2 receptor-dependent behavioral model provides estimates for doses of this compound that would be expected to selectively engage and activate central mGlu3 receptors in vivo.
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6
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Mastroiacovo F, Moyanova S, Cannella M, Gaglione A, Verhaeghe R, Bozza G, Madonna M, Motolese M, Traficante A, Riozzi B, Bruno V, Battaglia G, Lodge D, Nicoletti F. Genetic deletion of mGlu2 metabotropic glutamate receptors improves the short-term outcome of cerebral transient focal ischemia. Mol Brain 2017; 10:39. [PMID: 28821279 PMCID: PMC5562974 DOI: 10.1186/s13041-017-0319-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/09/2017] [Indexed: 12/23/2022] Open
Abstract
We have recently shown that pharmacological blockade of mGlu2 metabotropic glutamate receptors protects vulnerable neurons in the 4-vessel occlusion model of transient global ischemia, whereas receptor activation amplifies neuronal death. This raised the possibility that endogenous activation of mGlu2 receptors contributes to the pathophysiology of ischemic neuronal damage. Here, we examined this possibility using two models of transient focal ischemia: (i) the monofilament model of middle cerebral artery occlusion (MCAO) in mice, and (ii) the model based on intracerebral infusion of endothelin-1 (Et-1) in rats. Following transient MCAO, mGlu2 receptor knockout mice showed a significant reduction in infarct volume and an improved short-term behavioural outcome, as assessed by a neurological disability scale and the “grip test”. Following Et-1 infusion, Grm2 gene mutated Hannover Wistar rats lacking mGlu2 receptors did not show changes in the overall infarct volume as compared to their wild-type counterparts, although they showed a reduced infarct area in the agranular insular cortex. Interestingly, however, mGlu2 receptor-deficient rats performed better than wild-type rats in the adhesive tape test, in which these rats did not show the laterality preference typically observed after focal ischemia. These findings support the hypothesis that activation of mGlu2 receptors is detrimental in the post-ischemic phase, and support the use of mGlu2 receptor antagonists in the experimental treatment of brain ischemia.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Valeria Bruno
- IRCCS Neuromed, 86077, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy
| | | | - David Lodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Ferdinando Nicoletti
- IRCCS Neuromed, 86077, Pozzilli, Italy. .,Department of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy.
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7
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Lee KM, Coelho MA, Sern KR, Class MA, Bocz MD, Szumlinski KK. Anxiolytic effects of buspirone and MTEP in the Porsolt Forced Swim Test. CHRONIC STRESS 2017; 1. [PMID: 28884167 PMCID: PMC5584874 DOI: 10.1177/2470547017712985] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Traditionally, a reduction in floating behavior or immobility in the Porsolt forced swim
test is employed as a predictor of anti-depressant efficacy. However, over the past
several years, our studies of alcohol withdrawal-induced negative affect consistently
indicate the coincidence of increased anxiety-related behaviors on various behavioral
tests with reduced immobility in the forced swim test. Further, this
behavioral profile correlates with increased mGlu5 protein expression within limbic brain
regions. As the role for mGlu5 in anxiety is well established, we hypothesized that the
reduced immobility exhibited by alcohol-withdrawn mice when tested in the forced swim test
might reflect anxiety, possibly a hyper-reactivity to the acute swim stressor. Herein, we
evaluated whether or not the decreased forced swim test immobility during alcohol
withdrawal responds to systemic treatment with a behaviorally effective dose of the
prototypical anxiolytic, buspirone (5 mg/kg). We also determined the functional relevance
of the withdrawal-induced increase in mGlu5 expression for forced swim test behavior by
comparing the effects of buspirone to a behaviorally effective dose of the mGlu5 negative
allosteric modulator MTEP (3 mg/kg). Adult male C57BL/6J mice were subjected to a 14-day,
multi-bottle, binge-drinking protocol that elicits hyper-anxiety and increases
glutamate-related protein expression during early withdrawal. Control animals received
only water. At 24-h withdrawal, animals from each drinking condition were subdivided into
groups and treated with an intraperitoneal injection of buspirone, MTEP, or vehicle,
30 min prior to the forced swim test. Drug effects on general locomotor activity were also
assessed. As we reported previously, alcohol-withdrawn animals exhibited significantly
reduced immobility in the forced swim test compared to water controls. Both buspirone and
MTEP significantly increased immobility in alcohol-withdrawn animals, with a modest
increase also seen in water controls. No significant group differences were observed for
locomotor activity, indicating that neither anxiolytic was sedating. These results provide
predictive validity for increased swimming/reduced immobility in the forced swim test as a
model of anxiety and provide novel evidence in favor of mGlu5 inhibition as an effective
therapeutic strategy for treating hyper-anxiety during alcohol withdrawal.
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Affiliation(s)
- Kaziya M Lee
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9660
| | - Michal A Coelho
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9660
| | - Kimberly R Sern
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9660
| | - MacKayla A Class
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9660
| | - Mark D Bocz
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9660
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9660.,Department of Molecular, Cellular and Developmental Biology and the Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA, 93106-9625
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8
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Walsh DA, Brown JT, Randall AD. In vitro characterization of cell-level neurophysiological diversity in the rostral nucleus reuniens of adult mice. J Physiol 2017; 595:3549-3572. [PMID: 28295330 PMCID: PMC5451734 DOI: 10.1113/jp273915] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/09/2017] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS The nucleus reuniens (Re), a nucleus of the midline thalamus, is part of a cognitive network including the hippocampus and the medial prefrontal cortex. To date, very few studies have examined the electrophysiological properties of Re neurons at a cellular level. The majority of Re neurons exhibit spontaneous action potential firing at rest. This is independent of classical amino-acid mediated synaptic transmission. When driven by various forms of depolarizing current stimulus, Re neurons display considerable diversity in their firing patterns. As a result of the presence of a low threshold Ca2+ channel, spike output functions are strongly modulated by the prestimulus membrane potential. Finally, we describe a novel form of activity-dependant intrinsic plasticity that eliminates the high-frequency burst firing present in many Re neurons. These results provide a comprehensive summary of the intrinsic electrophysiological properties of Re neurons allowing us to better consider the role of the Re in cognitive processes. ABSTRACT The nucleus reuniens (Re) is the largest of the midline thalamic nuclei. We have performed a detailed neurophysiological characterization of neurons in the rostral Re of brain slices prepared from adult male mice. At resting potential (-63.7 ± 0.6 mV), ∼90% of Re neurons fired action potentials, typically continuously at ∼8 Hz. Although Re neurons experience a significant spontaneous barrage of fast, amino-acid-mediate synaptic transmission, this was not predominantly responsible for spontaneous spiking because firing persisted in the presence of glutamate and GABA receptor antagonists. With resting potential preset to -80 mV, -20 pA current injections revealed a mean input resistance of 615 MΩ and a mean time constant of 38 ms. Following cessation of this stimulus, a significant rebound potential was seen that was sometimes sufficiently large to trigger a short burst of very high frequency (100-300 Hz) firing. In most cells, short (2 ms), strong (2 nA) current injections elicited a single spike followed by a large afterdepolarizing potential which, when suprathreshold, generated high-frequency spiking. Similarly, in the majority of cells preset at -80 mV, 500 ms depolarizing current injections to cells led to a brief initial burst of very high-frequency firing, although this was lost when cells were preset at -72 mV. Biophysical and pharmacological experiments indicate a prominent role for T-type Ca2+ channels in the high-frequency bursting of Re neurons. Finally, we describe a novel form of activity-dependent intrinsic plasticity that persistently eliminates the burst firing potential of Re neurons.
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Affiliation(s)
- Darren A. Walsh
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical SchoolHatherly LaboratoryExeterUK
| | - Jonathan T. Brown
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical SchoolHatherly LaboratoryExeterUK
| | - Andrew D. Randall
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical SchoolHatherly LaboratoryExeterUK
- School of Clinical SciencesUniversity of BristolBristolUK
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9
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10
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McOmish CE, Demireva EY, Gingrich JA. Developmental expression of mGlu2 and mGlu3 in the mouse brain. Gene Expr Patterns 2016; 22:46-53. [PMID: 27818290 DOI: 10.1016/j.gep.2016.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 10/30/2016] [Accepted: 10/31/2016] [Indexed: 12/12/2022]
Abstract
The glutamatergic system directs central nervous system (CNS) neuronal activity and may underlie various neuropsychiatric disorders. Glutamate transmits its effects through multiple receptor classes. Class II metabotropic glutamate receptors, mGlu2 and mGlu3, play an important role in regulating synaptic release of different neurotransmitter systems and consequently modulate signaling across several neuronal subtypes. Drugs targeting mGlu2 and mGlu3 are seen as potential therapeutics for various psychiatric and neurological disorders, and defining their expression through development can aid in understanding their distinct function. Here, non-radioactive in situ hybridization was used to detect mGlu2 and mGlu3 mRNA in the CNS of 129SvEv mice at PN1, PN8, PN25, PN40, and PN100. At PN1, mGlu2 and mGlu3 are strongly expressed cortically, most notably in layer III and V. Subcortically, mGlu2 is detected in thalamic nuclei; mGlu3 is highly expressed in the striatum. By PN8, the most notable changes are in hippocampus and cortex, with mGlu2 densely expressed in the dentate gyrus, and showing increased cortical levels especially in medial cortex. At PN8, mGlu3 is observed in cortex and striatum, with highest levels detected in reticular thalamic nucleus. At PN25 patterns of expression approximated those observed across adulthood (PN40 & PN100): mGlu2 expression was high in cortex and dentate gyrus while mGlu3 showed expression in the reticular thalamic nucleus, cortex, and striatum. These studies provide a foundation for future research seeking to parse out the roles of mGlu2 from mGlu3, paving the way for better understanding of how these receptors regulate activity in the brain.
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Affiliation(s)
- Caitlin E McOmish
- Molecular Psychiatry, Florey Institute for Neuroscience and Mental Health, VIC, 3052, Australia; Department of Psychiatry, Columbia University, New York, NY 10032, USA.
| | - Elena Y Demireva
- Michigan State University, East Lansing, MI 48824, USA; Department of Psychiatry, Columbia University, New York, NY 10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA
| | - Jay A Gingrich
- Department of Psychiatry, Columbia University, New York, NY 10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA; Sackler Institute for Developmental Psychobiology, New York, NY 10032, USA
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11
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Li X, D'Souza MS, Niño AM, Doherty J, Cross A, Markou A. Attenuation of nicotine-taking and nicotine-seeking behavior by the mGlu2 receptor positive allosteric modulators AZD8418 and AZD8529 in rats. Psychopharmacology (Berl) 2016; 233:1801-14. [PMID: 26873083 DOI: 10.1007/s00213-016-4220-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/18/2016] [Indexed: 12/29/2022]
Abstract
RATIONALE Numerous medication development strategies seek to decrease nicotine consumption and prevent relapse to tobacco smoking by blocking glutamate transmission. Decreasing glutamate release by activating presynaptic inhibitory metabotropic glutamate (mGlu)2/3 receptors inhibits the reinforcing effects of nicotine and blocks cue-induced reinstatement of nicotine-seeking behavior in rats. However, the relative contribution of mGlu2 receptors in nicotine dependence is still unknown. OBJECTIVES The present study evaluated the role of mGlu2 receptors in nicotine-taking and nicotine-seeking behavior using the novel, relatively selective mGlu2 positive allosteric modulators (PAMs) AZD8418 and AZD8529. RESULTS Acute treatment with AZD8418 (0.37, 1.12, 3.73, 7.46, and 14.92 mg/kg) and AZD8529 (1.75, 5.83, 17.5, and 58.3 mg/kg) deceased nicotine self-administration and had no effect on food-maintained responding. Chronic treatment with AZD8418 attenuated nicotine self-administration, but tolerance to this effect developed quickly. The inhibition of nicotine self-administration by chronic AZD8529 administration persisted throughout the 14 days of treatment. Chronic treatment with either PAMs inhibited food self-administration. AZD8418 (acute) and AZD8529 (acute and subchronic) blocked cue-induced reinstatement of nicotine- and food-seeking behavior. CONCLUSIONS These findings indicate an important role for mGlu2 receptors in the reinforcing properties of self-administered nicotine and the motivational impact of cues that were previously associated with nicotine administration (i.e., cue-induced reinstatement of nicotine-seeking behavior). Thus, mGlu2 PAMs may be useful medications to assist people to quit tobacco smoking and prevent relapse.
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Affiliation(s)
- Xia Li
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Manoranjan S D'Souza
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Ana M Niño
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - James Doherty
- Present address: Sage Therapeutics, Cambridge, MA, 02142, USA
| | - Alan Cross
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, 02139, USA
| | - Athina Markou
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA.
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12
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Wood CM, Nicolas CS, Choi SL, Roman E, Nylander I, Fernandez-Teruel A, Kiianmaa K, Bienkowski P, de Jong TR, Colombo G, Chastagnier D, Wafford KA, Collingridge GL, Wildt SJ, Conway-Campbell BL, Robinson ESJ, Lodge D. Prevalence and influence of cys407* Grm2 mutation in Hannover-derived Wistar rats: mGlu2 receptor loss links to alcohol intake, risk taking and emotional behaviour. Neuropharmacology 2016; 115:128-138. [PMID: 26987983 DOI: 10.1016/j.neuropharm.2016.03.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/30/2022]
Abstract
Modulation of metabotropic glutamate 2 (mGlu2) receptor function has huge potential for treating psychiatric and neurological diseases. Development of drugs acting on mGlu2 receptors depends on the development and use of translatable animal models of disease. We report here a stop codon mutation at cysteine 407 in Grm2 (cys407*) that is common in some Wistar rats. Therefore, researchers in this field need to be aware of strains with this mutation. Our genotypic survey found widespread prevalence of the mutation in commercial Wistar strains, particularly those known as Han Wistar. Such Han Wistar rats are ideal for research into the separate roles of mGlu2 and mGlu3 receptors in CNS function. Previous investigations, unknowingly using such mGlu2 receptor-lacking rats, provide insights into the role of mGlu2 receptors in behaviour. The Grm2 mutant rats, which dominate some selectively bred lines, display characteristics of altered emotionality, impulsivity and risk-related behaviours and increased voluntary alcohol intake compared with their mGlu2 receptor-competent counterparts. In addition, the data further emphasize the potential therapeutic role of mGlu2 receptors in psychiatric and neurological disease, and indicate novel methods of studying the role of mGlu2 and mGlu3 receptors. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Christian M Wood
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - Celine S Nicolas
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - Sun-Lim Choi
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - Erika Roman
- Neuropharmacology, Addiction and Behaviour, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591, 751 24 Uppsala, Sweden
| | - Ingrid Nylander
- Neuropharmacology, Addiction and Behaviour, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591, 751 24 Uppsala, Sweden
| | - Alberto Fernandez-Teruel
- Department of Psychiatry and Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Kalervo Kiianmaa
- Department of Alcohol, Drugs and Addiction, National Institute for Health and Welfare, POB 30 00271 Helsinki, Finland
| | | | - Trynke R de Jong
- Department of Behavioural and Molecular Neuroendocrinology, University of Regensburg, 93040 Regensburg, Germany
| | - Giancarlo Colombo
- Neuroscience Institute, Section of Cagliari, National Research Council of Italy, I09042 Monserrato, CA, Italy
| | - Denis Chastagnier
- Janvier Labs, CS4105 Le Genest-Saint-Isle, F-53941 Saint-Berthevin, France
| | - Keith A Wafford
- Eli Lilly Research Laboratories, Windlesham, Surrey GU20 6PH, UK
| | - Graham L Collingridge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - Sheryl J Wildt
- Envigo, 8520 Allison Pointe Boulevard, Indianapolis IN 46250, USA
| | - Becky L Conway-Campbell
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
| | - Emma S J Robinson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK
| | - David Lodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol BS8 1TD, UK.
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13
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mGluR2/3 in the Lateral Amygdala is Required for Fear Extinction: Cortical Input Synapses onto the Lateral Amygdala as a Target Site of the mGluR2/3 Action. Neuropsychopharmacology 2015; 40:2916-28. [PMID: 26081171 PMCID: PMC4864627 DOI: 10.1038/npp.2015.145] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/07/2015] [Accepted: 05/20/2015] [Indexed: 01/13/2023]
Abstract
Various subtypes of metabotropic glutamate receptors (mGluRs) have been implicated in fear extinction, but mGluR2/3 subtype has not been tested. Here, we found that microinjection of an mGluR2/3 antagonist, LY341495, into the lateral amygdala (LA), but not into the adjacent central amygdala (CeA), impaired extinction retention without affecting within-session extinction. In contrast, we failed to detect any significant changes in motility and anxiety during a period when extinction training or retention was performed after LY341495 injection, suggesting that the effect of LY341495 is specific to conditioned responses. Subsequently, on the basis of a previous finding that a long-term potentiation of presynaptic efficacy at cortical input synapses onto the lateral amygdala (C-LA synapses) supports conditioned fear, we tested the hypothesis that activation of mGluR2/3 leads to fear extinction via a long-term weakening of presynaptic functions at C-LA synapses. Fear extinction produced a decrease in C-LA synaptic efficacy, whereas LY341495 infusion into the LA blocked this extinction-induced C-LA efficacy decrease without altering synaptic efficacy at other LA synapses. Furthermore, extinction enhanced paired pulse ratio (PPR) of EPSCs, which inversely correlates with presynaptic release probability, whereas LY341495 infusion into the LA attenuated the extinction-induced increase in PPR, suggesting the presence of mGluR2/3-dependent presynaptic changes after extinction. Consistently, extinction occluded a presynaptic form of depression at C-LA synapses, whereas the LY341495 infusion into the LA rescued this occlusion. Together, our findings suggest that mGluR2/3 is required for extinction retention and that the mGluR2/3 action is mediated by the long-term weakening of release probability at C-LA synapses.
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14
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Motolese M, Mastroiacovo F, Cannella M, Bucci D, Gaglione A, Riozzi B, Lütjens R, Poli SM, Celanire S, Bruno V, Battaglia G, Nicoletti F. Targeting type-2 metabotropic glutamate receptors to protect vulnerable hippocampal neurons against ischemic damage. Mol Brain 2015; 8:66. [PMID: 26496940 PMCID: PMC4619332 DOI: 10.1186/s13041-015-0158-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 10/15/2015] [Indexed: 11/10/2022] Open
Abstract
Background To examine whether metabotropic glutamate (mGlu) receptors have any role in mechanisms that shape neuronal vulnerability to ischemic damage, we used the 4-vessel occlusion (4-VO) model of transient global ischemia in rats. 4-VO in rats causes a selective death of pyramidal neurons in the hippocampal CA1 region, leaving neurons of the CA3 region relatively spared. We wondered whether changes in the expression of individual mGlu receptor subtypes selectively occur in the vulnerable CA1 region during the development of ischemic damage, and whether post-ischemic treatment with drugs targeting the selected receptor(s) affords neuroprotection. Results We found that 4-VO caused significantly reduction in the transcript of mGlu2 receptors in the CA1 region at times that preceded the anatomical evidence of neuronal death. Down-regulation of mGlu2 receptors was associated with reduced H3 histone acetylation at the Grm2 promoter. The transcripts of other mGlu receptor subtypes were unchanged in the CA1 region of 4-VO rats. Ischemia did not cause changes in mGlu2 receptor mRNA levels in the resistant CA3 region, which, interestingly, were lower than in the CA1 region. Targeting the mGlu2 receptors with selective pharmacologic ligands had profound effects on ishemic neuronal damage. Post-ischemic oral treatment with the selective mGlu2 receptor NAM (negative allosteric modulator), ADX92639 (30 mg/kg), was highly protective against ischemic neuronal death. In contrast, s.c. administration of the mGlu2 receptor enhancer, LY487379 (30 mg/kg), amplified neuronal damage in the CA1 region and extended the damage to the CA3 region. Conclusion These findings suggest that the mGlu2 receptor is an important player in mechanisms regulating neuronal vulnerability to ischemic damage, and that mGlu2 receptor NAMs are potential candidates in the experimental treatments of disorders characterized by brain hypoperfusion, such as hypovolemic shock and cardiac arrest.
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Affiliation(s)
- Marta Motolese
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Federica Mastroiacovo
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Milena Cannella
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Domenico Bucci
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Anderson Gaglione
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Barbara Riozzi
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Robert Lütjens
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland
| | - Sonia M Poli
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland
| | - Sylvain Celanire
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland.,Present address: Pragma Therapeutics, 74166, Saint-Julien-en-Genevois, France
| | - Valeria Bruno
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy
| | - Giuseppe Battaglia
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy
| | - Ferdinando Nicoletti
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077, Pozzilli, Italy. .,Department of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185, Rome, Italy.
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15
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LY395756, an mGluR2 agonist and mGluR3 antagonist, enhances NMDA receptor expression and function in the normal adult rat prefrontal cortex, but fails to improve working memory and reverse MK801-induced working memory impairment. Exp Neurol 2015; 273:190-201. [PMID: 26341392 DOI: 10.1016/j.expneurol.2015.08.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/06/2015] [Accepted: 08/25/2015] [Indexed: 11/22/2022]
Abstract
Targeting group II metabotropic glutamate receptors (mGluR2/3) has been proposed to correct the dysfunctional glutamatergic system, particularly NMDA receptor (NMDAR) hypofunction, for treatment of schizophrenia. However, how activation of mGluR2/3 affects NMDAR function in adult animals remains elusive. Here we show the effects of LY395756 (LY39), a compound acting as both an mGluR2 agonist and mGluR3 antagonist, on the NMDAR expression and function of normal adult rat prefrontal cortex (PFC) as well as working memory function in the MK801 model of schizophrenia. We found that in vivo administration of LY39 significantly increased the total protein levels of NMDAR subunits and NR2B phosphorylationin the PFC, along with the amplitude of NMDAR-mediated miniature excitatory postsynaptic currents (mEPSC) in the prefrontal cortical neurons. Moreover, LY39 also significantly increased mTOR and pmTOR expression, but not ERK1/2, Akt, and GSK3β, suggesting an activation of mTOR signaling. Indeed, the mTOR inhibitor rapamycin, and actinomycin-D, a transcription inhibitor, blocked the enhanced effects of LY39 on NMDAR-mEPSCs. These results indicate that LY39 regulates NMDAR expression and function through unidentified mTOR-mediated protein synthesis in the normal adult rat PFC. However, this change is insufficient to affect working memory function in normal animals, nor to reverse the MK801-induced working memory deficit. Our data provide the first evidence of an in vivo effect of a novel compound that acts as both an mGluR2 agonist and mGluR3 antagonist on synaptic NMDAR expression and function in the adult rat PFC, although its effect -on PFC-dependent cognitive function remains to be explored.
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16
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Monn JA, Prieto L, Taboada L, Pedregal C, Hao J, Reinhard MR, Henry SS, Goldsmith PJ, Beadle CD, Walton L, Man T, Rudyk H, Clark B, Tupper D, Baker SR, Lamas C, Montero C, Marcos A, Blanco J, Bures M, Clawson DK, Atwell S, Lu F, Wang J, Russell M, Heinz BA, Wang X, Carter JH, Xiang C, Catlow JT, Swanson S, Sanger H, Broad LM, Johnson MP, Knopp KL, Simmons RMA, Johnson BG, Shaw DB, McKinzie DL. Synthesis and Pharmacological Characterization of C4-Disubstituted Analogs of 1S,2S,5R,6S-2-Aminobicyclo[3.1.0]hexane-2,6-dicarboxylate: Identification of a Potent, Selective Metabotropic Glutamate Receptor Agonist and Determination of Agonist-Bound Human mGlu2 and mGlu3 Amino Terminal Domain Structures. J Med Chem 2015; 58:1776-94. [DOI: 10.1021/jm501612y] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James A. Monn
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Lourdes Prieto
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Lorena Taboada
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Concepcion Pedregal
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Junliang Hao
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Matt R. Reinhard
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Steven S. Henry
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Paul J. Goldsmith
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Christopher D. Beadle
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Lesley Walton
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Teresa Man
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Helene Rudyk
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Barry Clark
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - David Tupper
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - S. Richard Baker
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Carlos Lamas
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Carlos Montero
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Alicia Marcos
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Jaime Blanco
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Mark Bures
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - David K. Clawson
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Shane Atwell
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Frances Lu
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Jing Wang
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Marijane Russell
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Beverly A. Heinz
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Xushan Wang
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Joan H. Carter
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Chuanxi Xiang
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - John T. Catlow
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Steven Swanson
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Helen Sanger
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Lisa M. Broad
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Michael P. Johnson
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Kelly L. Knopp
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Rosa M. A. Simmons
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Bryan G. Johnson
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - David B. Shaw
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - David L. McKinzie
- Discovery Chemistry
Research and Technologies, ‡Quantitative Biology, §Structural Biology, ∥Drug Disposition,
and ⊥Neuroscience
Research, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
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17
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De Filippis B, Lyon L, Taylor A, Lane T, Burnet PWJ, Harrison PJ, Bannerman DM. The role of group II metabotropic glutamate receptors in cognition and anxiety: comparative studies in GRM2(-/-), GRM3(-/-) and GRM2/3(-/-) knockout mice. Neuropharmacology 2014; 89:19-32. [PMID: 25158312 PMCID: PMC4259517 DOI: 10.1016/j.neuropharm.2014.08.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/06/2014] [Accepted: 08/14/2014] [Indexed: 01/28/2023]
Abstract
Group II metabotropic glutamate receptors (mGlu2 and mGlu3, encoded by GRM2 and GRM3) have been implicated in both cognitive and emotional processes, although their precise role remains to be established. Studies with knockout (KO) mice provide an important approach for investigating the role of specific receptor genes in behaviour. In the present series of experiments we extended our prior characterisation of GRM2/3−/− double KO mice and, in complementary experiments, investigated the behavioural phenotype of single GRM2−/− and GRM3−/− mice. We found no consistent effect on anxiety in either the double or single KO mice. The lack of an anxiety phenotype in any of the lines contrasts with the clear anxiolytic effects of mGlu2/3 ligands. Motor co-ordination was impaired in GRM2/3−/− mice, but spared in single GRM2−/− and GRM3−/− mice. Spatial working memory (rewarded alternation) testing on the elevated T-maze revealed a deficit in GRM2−/− mice throughout testing, whereas GRM3−/− mice exhibited a biphasic effect (initially impaired, but performing better than controls by the end of training). A biphasic effect on activity levels was seen for the GRM2−/− mice. Overall, the phenotype in both GRM2−/− and GRM3−/− mice was less pronounced – if present at all – compared to GRM2/3−/− mice, across the range of task domains. This is consistent with possible redundancy of function and/or compensation in the single KO lines. Results are discussed with reference to a possible role for group II metabotropic glutamate receptors at the interface between arousal and behavioural performance, according to an inverted U-shaped function. GRM2−/− mice exhibited impaired spatial short-term memory (rewarded alternation). GRM3−/− mice displayed bi-directional effects on this spatial short-term memory task. GRM2−/− mice displayed bi-directional effects on activity levels. There was no consistent anxiety effect in either double or single knockout mice. Behavioural phenotypes were weaker (or absent) in single than in double knockout mice.
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Affiliation(s)
- Bianca De Filippis
- Section of Behavioural Neuroscience, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanita, Viale Regina Elena, 299, I-00161 Rome, Italy.
| | - Louisa Lyon
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Amy Taylor
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK
| | - Tracy Lane
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Philip W J Burnet
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Paul J Harrison
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - David M Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK.
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18
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Zhang S, Jin X, You Z, Wang S, Lim G, Yang J, McCabe M, Li N, Marota J, Chen L, Mao J. Persistent nociception induces anxiety-like behavior in rodents: role of endogenous neuropeptide S. Pain 2014; 155:1504-1515. [PMID: 24793908 DOI: 10.1016/j.pain.2014.04.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/17/2014] [Accepted: 04/23/2014] [Indexed: 11/30/2022]
Abstract
Anxiety disorder is a comorbid condition of chronic pain. Analgesics and anxiolytics, subject to addiction and abuse, are currently used to manage pain and anxiety symptoms. However, the cellular mechanism underlying chronic pain and anxiety interaction remains to be elucidated. We report that persistent nociception following peripheral nerve injury induced anxiety-like behavior in rodents. Brain expression and release of neuropeptide S (NPS), a proposed endogenous anxiolytic peptide, was diminished in rodents with coexisting nociceptive and anxiety-like behaviors. Intracerebroventricular administration of exogenous NPS concurrently improved both nociceptive and anxiety-like behaviors. At the cellular level, NPS enhanced intra-amygdaloidal inhibitory transmission by increasing presynaptic gamma-aminobutyric acid (GABA) release from interneurons. These findings indicate that the interaction between nociceptive and anxiety-like behaviors in rodents may be regulated by the altered NPS-mediated intra-amygdaloidal GABAergic inhibition. The data suggest that enhancing the brain NPS function may be a new strategy to manage comorbid pain and anxiety.
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Affiliation(s)
- Shuzhuo Zhang
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA Department of Anesthesia and Pain Therapy, Beijing Tiantan Hospital Affiliated to Capital Medical University, Beijing 100050, China
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19
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Klein A, Ultved L, Adamsen D, Santini M, Tobeña A, Fernandez-Teruel A, Flores P, Moreno M, Cardona D, Knudsen G, Aznar S, Mikkelsen J. 5-HT2A and mGlu2 receptor binding levels are related to differences in impulsive behavior in the Roman Low- (RLA) and High- (RHA) avoidance rat strains. Neuroscience 2014; 263:36-45. [DOI: 10.1016/j.neuroscience.2013.12.063] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/26/2013] [Accepted: 12/27/2013] [Indexed: 10/25/2022]
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20
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Procaccini C, Maksimovic M, Aitta-Aho T, Korpi ER, Linden AM. Reversal of novelty-induced hyperlocomotion and hippocampal c-Fos expression in GluA1 knockout male mice by the mGluR2/3 agonist LY354740. Neuroscience 2013; 250:189-200. [PMID: 23867766 DOI: 10.1016/j.neuroscience.2013.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/07/2013] [Accepted: 07/03/2013] [Indexed: 01/16/2023]
Abstract
Dysfunctional glutamatergic neurotransmission has been implicated in schizophrenia and mood disorders. As a putative model for these disorders, a mouse line lacking the GluA1 subunit (GluA1-KO) of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor displays a robust novelty-induced hyperlocomotion associated with excessive neuronal activation in the hippocampus. Agonists of metabotropic glutamate 2/3 receptors (mGluR2/3) inhibit glutamate release in various brain regions and they have been shown to inhibit neuronal activation in the hippocampus. Here, we tested a hypothesis that novelty-induced hyperlocomotion in the GluA1-KO mice is mediated via excessive hippocampal neuronal activation by analyzing whether an mGluR2/3 agonist inhibits this phenotypic feature. GluA1-KO mice and littermate wildtype (WT) controls were administered with (1S,2S,5R,6S)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (LY354740) (15 mg/kg, i.p.) 30 min before a 2-h exposure to novel arenas after which c-Fos immunopositive cells were analyzed in the hippocampus. LY354740 (15 mg/kg) decreased hyperactivity in male GluA1-KO mice, with only a minimal effect in WT controls. This was observed in two cohorts of animals, one naïve to handling and injections, another pre-handled and accustomed to injections. LY354740 (15 mg/kg) also reduced the excessive c-Fos expression in the dorsal hippocampal CA1 pyramidal cell layer in maleGluA1-KO mice, while not affecting c-Fos levels in WT mice. In female mice, no significant effect for LY354740 (15 mg/kg) on hyperactive behavior or hippocampal c-Fos was observed in either genotype or treatment cohort. A higher dose of LY354740 (30 mg/kg) alleviated hyperlocomotion of GluA1-KO males, but not that of GluA1-KO females. In conclusion, the excessive behavioral hyperactivity of GluA1-KO mice can be partly prevented by reducing neuronal excitability in the hippocampus with the mGluR2/3 agonist suggesting that the hippocampal reactivity is strongly involved in the behavioral phenotype of GluA1-KO mice.
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Affiliation(s)
- C Procaccini
- Institute of Biomedicine/Pharmacology, Biomedicum Helsinki, P.O.B. 63, FIN-00014 University of Helsinki, Finland
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21
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Monn JA, Valli MJ, Massey SM, Hao J, Reinhard MR, Bures MG, Heinz BA, Wang X, Carter JH, Getman BG, Stephenson GA, Herin M, Catlow JT, Swanson S, Johnson BG, McKinzie DL, Henry SS. Synthesis and Pharmacological Characterization of 4-Substituted-2-Aminobicyclo[3.1.0]hexane-2,6-dicarboxylates: Identification of New Potent and Selective Metabotropic Glutamate 2/3 Receptor Agonists. J Med Chem 2013; 56:4442-55. [DOI: 10.1021/jm4000165] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James A. Monn
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Matthew J. Valli
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Steven M. Massey
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Junliang Hao
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Matthew R. Reinhard
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Mark G. Bures
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Beverly A. Heinz
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Xushan Wang
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Joan H. Carter
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Brian G. Getman
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Gregory A. Stephenson
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Marc Herin
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - John T. Catlow
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Steven Swanson
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Bryan G. Johnson
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - David L. McKinzie
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Steven S. Henry
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
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22
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Wang MJ, Li YC, Snyder MA, Wang H, Li F, Gao WJ. Group II metabotropic glutamate receptor agonist LY379268 regulates AMPA receptor trafficking in prefrontal cortical neurons. PLoS One 2013; 8:e61787. [PMID: 23593498 PMCID: PMC3625159 DOI: 10.1371/journal.pone.0061787] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 03/13/2013] [Indexed: 12/26/2022] Open
Abstract
Group II metabotropic glutamate receptor (mGluR) agonists have emerged as potential treatment drugs for schizophrenia and other neurological disorders, whereas the mechanisms involved remain elusive. Here we examined the effects of LY379268 (LY37) on the expression and trafficking of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits GluA1 and GluA2 in prefrontal neurons. We show that LY37 significantly increased the surface and total expression of both GluA1 and GluA2 subunits in cultured prefrontal neurons and in vivo. This effect was mimicked by the selective mGluR2 agonist LY395756 and was blocked by mGluR2/3 antagonist LY341495. Moreover, we found that both GluA1 and GluA2 subunits were colocalized with PSD95 but not synapsin I, suggesting a postsynaptic localization. Consistently, treatment with LY37 significantly increased the amplitude, but not frequency, of miniature excitatory postsynaptic currents. Further, actinomycin-D blocked LY37's effects, suggesting a transcriptional regulation. In addition, application of glycogen synthase kinase-3beta (GSK-3β) inhibitor completely blocked LY37's effect on GluA2 surface expression, whereas GSK-3β inhibitor itself induced decreases in the surface and total protein levels of GluA1, but not GluA2 subunits. This suggests that GSK-3β differentially mediates GluA1 and GluA2 trafficking. Further, LY37 significantly increased the phosphorylation, but not total protein, of extracellular signal-regulated kinase 1/2 (ERK1/2). Neither ERK1/2 inhibitor PD98059 alone nor PD98059 combined with LY37 treatment induced changes in GluA1 or GluA2 surface expression or total protein levels. Our data thus suggest that mGluR2/3 agonist regulates postsynaptic AMPA receptors by affecting the synaptic trafficking of both GluA1 and GluA2 subunits and that the regulation is likely through ERK1/2 signaling in GluA1 and/or both ERK1/2 and GSK-3β signaling pathways in the GluA2 subunit.
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Affiliation(s)
- Min-Juan Wang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Neurobiology and Anatomy, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yan-Chun Li
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Melissa A. Snyder
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Huaixing Wang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Feng Li
- Department of Neurobiology and Anatomy, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou, China
- * E-mail: (WJG); (FL)
| | - Wen-Jun Gao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (WJG); (FL)
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23
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Antagonists reversibly reverse chemical LTD induced by group I, group II and group III metabotropic glutamate receptors. Neuropharmacology 2013; 74:135-46. [PMID: 23542080 DOI: 10.1016/j.neuropharm.2013.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/25/2013] [Accepted: 03/07/2013] [Indexed: 11/21/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are implicated in many neurological and psychiatric diseases and are the targets of therapeutic agents currently in clinical development. Their activation has diverse effects in the central nervous system (CNS) that includes an involvement in synaptic plasticity. We previously reported that the brief exposure of hippocampal slices to dihydroxyphenylglycine (DHPG) can result in a long-term depression (LTD) of excitatory synaptic transmission. Surprisingly, this LTD could be fully reversed by mGlu receptor antagonists in a manner that was itself fully reversible upon washout of the antagonist. Here, 15 years after the discovery of DHPG-LTD and its reversible reversibility, we summarise these initial findings. We then present new data on DHPG-LTD, which demonstrates that evoked epileptiform activity triggered by activation of group I mGlu receptors can also be reversibly reversed by mGlu receptor antagonists. Furthermore, we show that the phenomenon of reversible reversibility is not specific to group I mGlu receptors. We report that activation of group II mGlu receptors in the temporo-ammonic pathway (TAP) and mossy fibre pathway within the hippocampus and in the cortical input to neurons of the lateral amygdala induces an LTD that is reversed by LY341495, a group II mGlu receptor antagonist. We also show that activation of group III mGlu8 receptors induces an LTD at lateral perforant path inputs to the dentate gyrus and that this LTD is reversed by MDCPG, an mGlu8 receptor antagonist. In conclusion, we have shown that activation of representative members of each of the three groups of mGlu receptors can induce forms of LTD than can be reversed by antagonists, and that in each case washout of the antagonist is associated with the re-establishment of the LTD. This article is part of the Special Issue entitled 'Glutamate Receptor-Dependent Synaptic Plasticity'.
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24
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Crabtree JW, Lodge D, Bashir ZI, Isaac JTR. GABAA , NMDA and mGlu2 receptors tonically regulate inhibition and excitation in the thalamic reticular nucleus. Eur J Neurosci 2013; 37:850-9. [PMID: 23294136 DOI: 10.1111/ejn.12098] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/13/2012] [Accepted: 11/20/2012] [Indexed: 01/30/2023]
Abstract
Traditionally, neurotransmitters are associated with a fast, or phasic, type of action on neurons in the central nervous system (CNS). However, accumulating evidence indicates that γ-aminobutyric acid (GABA) and glutamate can also have a continual, or tonic, influence on these cells. Here, in voltage- and current-clamp recordings in rat brain slices, we identify three types of tonically active receptors in a single CNS structure, the thalamic reticular nucleus (TRN). Thus, TRN contains constitutively active GABAA receptors (GABAA Rs), which are located on TRN neurons and generate a persistent outward Cl(-) current. When TRN neurons are depolarized, blockade of this current increases their action potential output in response to current injection. Furthermore, TRN contains tonically active GluN2B-containing N-methyl-D-aspartate receptors (NMDARs). These are located on reticuloreticular GABAergic terminals in TRN and generate a persistent facilitation of vesicular GABA release from these terminals. In addition, TRN contains tonically active metabotropic glutamate type 2 receptors (mGlu2Rs). These are located on glutamatergic cortical terminals in TRN and generate a persistent reduction of vesicular glutamate release from these terminals. Although tonically active GABAA Rs, NMDARs and mGlu2Rs operate through different mechanisms, we propose that the continual and combined activity of these three receptor types ultimately serves to hyperpolarize TRN neurons, which will differentially affect the output of these cells depending upon the current state of their membrane potential. Thus, when TRN cells are relatively depolarized, their firing in single-spike tonic mode will be reduced, whereas when these cells are relatively hyperpolarized, their ability to fire in multispike burst mode will be facilitated.
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Affiliation(s)
- John W Crabtree
- Medical Research Council Centre for Synaptic Plasticity, School of Physiology and Pharmacology, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
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25
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Mercier MS, Lodge D, Fang G, Nicolas CS, Collett VJ, Jane DE, Collingridge GL, Bortolotto ZA. Characterisation of an mGlu8 receptor-selective agonist and antagonist in the lateral and medial perforant path inputs to the dentate gyrus. Neuropharmacology 2012; 67:294-303. [PMID: 23220400 DOI: 10.1016/j.neuropharm.2012.11.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 11/22/2012] [Accepted: 11/23/2012] [Indexed: 02/06/2023]
Abstract
Since its characterisation in 2001, the mGlu8-selective agonist DCPG has been widely used to explore the potential functional role of this group III mGlu receptor within the central nervous system. This research has implicated mGlu8 receptors in a number of disease states and conditions such as epilepsy and anxiety, suggesting that mGlu8-selective ligands may hold important therapeutic potential. However, there is evidence that DCPG exerts off-target effects at higher concentrations, limiting its use as an mGlu8-selective agonist. Here, we have used field recordings in rat hippocampal slices to investigate the effects of DCPG in the lateral perforant path (LPP), a pathway known to express high levels of mGlu8. We show that DCPG does inhibit excitatory transmission in this pathway, but produces a biphasic concentration-response curve suggesting activation of two distinct receptor types. The putative mGlu8-selective antagonist MDCPG antagonises the high, but not the low, potency component of this concentration-response curve. In addition, higher concentrations of DCPG also depress excitatory transmission in the medial perforant path (MPP), a pathway expressing very low levels of mGlu8 receptors. Experiments in slices from mice lacking mGlu8 receptors indicate that concentrations of DCPG >1 μM produce large non-selective effects in both the LPP and MPP. Further experiments in slices from mGlu2, 4 and 7 knock-out mice, as well as in an mGlu2-deficient substrain of Wistar rat, reveal that these non-selective effects are mediated primarily by mGlu2 receptors. Taken together, our results confirm the mGlu8-selectivity of DCPG at submicromolar concentrations, but suggest that care must be taken when employing higher concentrations of the agonist, which may additionally activate mGlu2 receptors, especially at synapses where their expression is high. MDCPG may be a useful tool in determining whether observable DCPG effects are attributable to mGlu8, versus mGlu2, receptor activation.
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Affiliation(s)
- Marion S Mercier
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Dorothy Hodgkin Building, Bristol BS1 3NY, UK
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26
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Romei C, Raiteri M, Raiteri L. Glycine release is regulated by metabotropic glutamate receptors sensitive to mGluR2/3 ligands and activated by N-acetylaspartylglutamate (NAAG). Neuropharmacology 2012; 66:311-6. [PMID: 22659408 DOI: 10.1016/j.neuropharm.2012.05.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 04/30/2012] [Accepted: 05/22/2012] [Indexed: 10/28/2022]
Abstract
The presence of metabotropic glutamate receptors (mGluRs) of group II modulating glycine exocytosis from glycinergic nerve endings of mouse spinal cord was investigated. Purified synaptosomes were selectively prelabeled with [(3)H]glycine through the neuronal transporter GlyT2 and subsequently depolarized by superfusion with 12 mM KCl. The selective mGluR2/3 agonist LY379268 inhibited the K(+)-evoked overflow of [(3)H]glycine in a concentration-dependent manner (EC(50) about 0.2 nM). The effect of LY379268 was prevented by the selective mGluR2/3 antagonist LY341495 (IC(50) about 1 nM). N-acetylaspartylglutamate (NAAG) inhibited [(3)H]glycine overflow with extraordinary potency (EC(50) about 50 fmol). In contrast, glutamate was ineffective up to 0.1 nM, excluding that glutamate contamination of commercial NAAG samples is responsible for the reported activity of NAAG at mGluR3. LY341495 antagonized the NAAG inhibition of [(3)H]glycine release. The effect of a combination of maximally effective concentrations of LY379268 and NAAG exhibited no additivity. The non-hydrolysable NAAG analogue N-acetylaspartyl-β-linked glutamate (β-NAAG) antagonized NAAG and LY379268. In conclusion, our results show that glycinergic nerve endings in spinal cord are endowed with group II mGluRs mediating inhibition of glycine exocytosis. NAAG can activate these presynaptic receptors with extremely high affinity and with characteristics compatible with the reported mGluR3 pharmacology. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Cristina Romei
- Department of Experimental Medicine, Pharmacology and Toxicology Unit, University of Genoa, Genoa, Italy
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27
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Pharmacological profiling of native group II metabotropic glutamate receptors in primary cortical neuronal cultures using a FLIPR. Neuropharmacology 2012; 66:264-73. [PMID: 22659090 DOI: 10.1016/j.neuropharm.2012.05.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 05/14/2012] [Accepted: 05/15/2012] [Indexed: 01/12/2023]
Abstract
The group II metabotropic glutamate (mGlu) receptors comprised of the mGlu2 and mGlu3 receptor subtypes have gained recognition in recent years as potential targets for psychiatric disorders, including anxiety and schizophrenia. In addition to studies already indicating which subtype mediates the anxiolytic and anti-psychotic effects observed in disease models, studies to help further define the preferred properties of selective group II mGlu receptor ligands will be essential. Comparison of the in vitro properties of these ligands to their in vivo efficacy and tolerance profiles may help provide these additional insights. We have developed a relatively high-throughput native group II mGlu receptor functional assay to aid this characterisation. We have utilised dissociated primary cortical neuronal cultures, which after 7 days in vitro have formed functional synaptic connections and display periodic and spontaneous synchronised calcium (Ca(2+)) oscillations in response to intrinsic action potential bursts. We herein demonstrate that in addition to non-selective group II mGlu receptor agonists, (2R,4R)-APDC, LY379268 and DCG-IV, a selective mGlu2 agonist, LY541850, and mGlu2 positive allosteric modulators, BINA and CBiPES, inhibit the frequency of synchronised Ca(2+) oscillations in primary cultures of rat and mouse cortical neurons. Use of cultures from wild-type, mGlu2(-/-), mGlu3(-/-) and mGlu2/3(-/-) mice allowed us to further probe the contribution of mGlu2 and mGlu3, and revealed LY541850 to be a partial mGlu2 agonist and a full mGlu3 antagonist. Overnight pre-treatment of cultures with these ligands revealed a preferred desensitisation profile after treatment with a positive allosteric modulator. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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28
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Durand D, Carniglia L, Caruso C, Lasaga M. mGlu3 receptor and astrocytes: partners in neuroprotection. Neuropharmacology 2012; 66:1-11. [PMID: 22564439 DOI: 10.1016/j.neuropharm.2012.04.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 03/28/2012] [Accepted: 04/08/2012] [Indexed: 01/11/2023]
Abstract
Astrocytes are currently studied intensively because of their now highlighted relevance as key players with neurons that modulate a wide range of central functions, from synaptic plasticity and synaptogenesis to regulation of metabolic and neuroinflammatory processes. Since the discovery of mGlu3 receptors on astrocytes, accumulating evidence supports a role of these receptors not only in maintaining synaptic homeostasis and treating psychiatric disorders but also in promoting astrocyte survival in several pathologic conditions. This review focuses on providing up-to-date knowledge regarding effects of activating astroglial mGlu3 receptors on psychiatric disorders, astrocyte and neuronal survival, and neurodegenerative diseases. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Daniela Durand
- Instituto de Investigaciones Biomédicas (INBIOMED), School of Medicine, University of Buenos Aires, Paraguay 2155 Piso 10, CABA 1121 Buenos Aires, Argentina.
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29
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Lucas SJ, Bortolotto ZA, Collingridge GL, Lodge D. Selective activation of either mGlu2 or mGlu3 receptors can induce LTD in the amygdala. Neuropharmacology 2012; 66:196-201. [PMID: 22531751 DOI: 10.1016/j.neuropharm.2012.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 03/15/2012] [Accepted: 04/02/2012] [Indexed: 11/18/2022]
Abstract
Group II metabotropic glutamate (mGlu) receptors are known to induce a long-term depression (LTD) of synaptic transmission in many brain regions including the amygdala. However the roles of the individual receptor subtypes, mGlu2 and mGlu3, in LTD are not well understood. In particular, it is unclear whether activation of mGlu3 receptors is sufficient to induce LTD at synapses in the CNS. In the present study, advantage was taken of a Wistar rat strain not expressing mGlu2 receptors (Ceolin et al., 2011) to investigate the function of mGlu3 receptors in the amygdala. In this preparation, the group II agonist, DCG-IV induced an LTD of the cortical, but not the intra-nuclear, synaptic input to the lateral amygdala. This LTD was concentration dependent and was blocked by the group II mGlu receptor antagonist, LY341495. To investigate further the role of mGlu3 receptors, we used LY395756 (an mGlu2 agonist and mGlu3 antagonist), which acts as a pure mGlu3 receptor antagonist in this rat strain. This compound alone had no effect on basal synaptic transmission, but blocked the LTD induced by DCG-IV. Furthermore, we found that DCG-IV also induces LTD in mGlu2 receptor knock-out (KO) mice to a similar extent as in wild-type mice. This confirms that the activation of mGlu3 receptors alone is sufficient to induce LTD at this amygdala synapse. To address whether mGlu2 activation alone is also sufficient to induce LTD at this synapse we used LY541850 (the active enantiomer of LY395756) in wild-type mice. LY541850 induced a substantial LTD showing that either receptor alone is capable of inducing LTD in this pathway. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Sarah J Lucas
- MRC Centre for Synaptic Plasticity, University of Bristol, Bristol BS8 1TD, UK.
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30
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Hanna L, Ceolin L, Lucas S, Monn J, Johnson B, Collingridge G, Bortolotto Z, Lodge D. Differentiating the roles of mGlu2 and mGlu3 receptors using LY541850, an mGlu2 agonist/mGlu3 antagonist. Neuropharmacology 2012; 66:114-21. [PMID: 22445601 DOI: 10.1016/j.neuropharm.2012.02.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/24/2012] [Accepted: 02/29/2012] [Indexed: 10/28/2022]
Abstract
Despite the potential therapeutic relevance of group II metabotropic glutamate (mGlu) receptors, there has been a lack of pharmacological tools for separating the roles of mGlu2 and mGlu3 receptor subtypes. LY541850 was claimed from human mGlu receptors expressed in non-neuronal cells to be a selective orthosteric mGlu2 agonist and mGlu3 antagonist. We have verified this pharmacological profile of LY541850 in hippocampal slices. Field excitatory post-synaptic potentials (fEPSPs) evoked by stimulation of the temporo-ammonic path (TAP) input to CA1 stratum lacunosum moleculare (SLM) were inhibited by LY541850 in mGlu3-/- mice (EC(50) 38 nM) and wild-type littermates (EC(50) 42 nM) to a similar extent but were not significantly affected in mGlu2-/- mice. The group II agonist, DCG-IV, inhibited the fEPSP in all three genotypes. Co-application of DCG-IV and LY541850 in mGlu3-/- and wild-type littermates resulted in an additive effect, whereas in mGlu2-/- mice, LY541850 reversed the inhibitory action of DCG-IV. These results confirm the selective mGlu2 agonist and mGlu3 antagonist actions of LY541850. A similar profile of activity was seen in medial perforant path synapse to the dentate gyrus. Systemic administration of LY541850 to wild-type mice, reduced the increase in locomotor activity following both phencyclidine and amphetamine administration. These data support the hypothesis that mGlu2 receptors mediate the antipsychotic effects of mixed group II agonists. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Lydia Hanna
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
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