1
|
Yang L, Liu W, Shi L, Wu J, Zhang W, Chuang YA, Redding-Ochoa J, Kirkwood A, Savonenko AV, Worley PF. NMDA Receptor-Arc Signaling Is Required for Memory Updating and Is Disrupted in Alzheimer's Disease. Biol Psychiatry 2023; 94:706-720. [PMID: 36796600 PMCID: PMC10423741 DOI: 10.1016/j.biopsych.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/16/2023]
Abstract
BACKGROUND Memory deficits are central to many neuropsychiatric diseases. During acquisition of new information, memories can become vulnerable to interference, yet mechanisms that underlie interference are unknown. METHODS We describe a novel transduction pathway that links the NMDA receptor (NMDAR) to AKT signaling via the immediate early gene Arc and evaluate its role in memory. The signaling pathway is validated using biochemical tools and transgenic mice, and function is evaluated in assays of synaptic plasticity and behavior. The translational relevance is evaluated in human postmortem brain. RESULTS Arc is dynamically phosphorylated by CaMKII (calcium/calmodulin-dependent protein kinase II) and binds the NMDAR subunits NR2A/NR2B and a previously unstudied PI3K (phosphoinositide 3-kinase) adapter p55PIK (PIK3R3) in vivo in response to novelty or tetanic stimulation in acute slices. NMDAR-Arc-p55PIK recruits p110α PI3K and mTORC2 (mechanistic target of rapamycin complex 2) to activate AKT. NMDAR-Arc-p55PIK-PI3K-mTORC2-AKT assembly occurs within minutes of exploratory behavior and localizes to sparse synapses throughout hippocampal and cortical regions. Studies using conditional (Nestin-Cre) p55PIK deletion mice indicate that NMDAR-Arc-p55PIK-PI3K-mTORC2-AKT functions to inhibit GSK3 and mediates input-specific metaplasticity that protects potentiated synapses from subsequent depotentiation. p55PIK conditional knockout mice perform normally in multiple behaviors including working memory and long-term memory tasks but exhibit deficits indicative of increased vulnerability to interference in both short-term and long-term paradigms. The NMDAR-AKT transduction complex is reduced in postmortem brain of individuals with early Alzheimer's disease. CONCLUSIONS A novel function of Arc mediates synapse-specific NMDAR-AKT signaling and metaplasticity that contributes to memory updating and is disrupted in human cognitive disease.
Collapse
Affiliation(s)
- Liuqing Yang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wenxue Liu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Linyuan Shi
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jing Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wenchi Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yang-An Chuang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Javier Redding-Ochoa
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alfredo Kirkwood
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alena V Savonenko
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| | - Paul F Worley
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| |
Collapse
|
2
|
Shi P, Hu L, Ren H, Dai Q. Reward enhances resilience to chronic social defeat stress in mice: Neural ECs and mGluR5 mechanism via neuroprotection in VTA and DRN. Front Psychiatry 2023; 14:1084367. [PMID: 36873216 PMCID: PMC9978385 DOI: 10.3389/fpsyt.2023.1084367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 01/13/2023] [Indexed: 02/18/2023] Open
Abstract
INTRODUCTION Stress often leads to emotional disorders such as depression. The reward might render this effect through the enhancement of stress resilience. However, the effect of reward on stress resilience under different intensities of stress needs more evidence, and its potential neural mechanism has been poorly revealed. It has been reported that the endogenous cannabinoid system (ECs) and downstream metabolic glutamate receptor 5 (mGluR5) are closely related to stress and reward, which might be the potential cerebral mechanism between reward and stress resilience, but there is a lack of direct evidence. This study aims to observe the effect of reward on stress resilience under different intensities of stress and further explore potential cerebral mechanisms underlying this effect. METHODS Using the chronic social defeat stress model, we applied reward (accompanied by a female mouse) under different intensities of stress in mice during the modeling process. The impact of reward on stress resilience and the potential cerebral mechanism were observed after modeling through behavioral tests and biomolecules. RESULTS The results showed that stronger stress led to higher degrees of depression-like behavior. Reward reduced depression-like behavior and enhanced stress resilience (all p-value <0.05) (more social interaction in the social test, less immobility time in the forced swimming test, etc.), with a stronger effect under the large stress. Furthermore, the mRNA expression levels of CB1 and mGluR5, the protein expression level of mGluR5, and the expression level of 2-AG (2-arachidonoylglycerol) in both ventral tegmental area (VTA) and dorsal raphe nucleus (DRN) were significantly upregulated by reward after modeling (all p-value <0.05). However, the protein expression of CB1 in VTA and DRN and the expression of AEA (anandamide) in VTA did not differ significantly between groups. Intraperitoneal injection of a CB1 agonist (URB-597) during social defeat stress significantly reduced depression-like behavior compared with a CB1 inhibitor (AM251) (all p-value <0.05). Interestingly, in DRN, the expression of AEA in the stress group was lower than that of the control group, with or without reward (all p-value <0.05). DISCUSSION These findings demonstrate that combined social and sexual reward has a positive effect on stress resilience during chronic social defeat stress, potentially by influencing the ECs and mGluR5 in VTA and DRN.
Collapse
Affiliation(s)
- Peixia Shi
- Department of Medical Psychology, Army Medical University, Chongqing, China.,Department of Neurology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Linlin Hu
- Department of Neurology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hui Ren
- Department of Nursing Psychology, Army Medical University, Chongqing, China
| | - Qin Dai
- Department of Medical Psychology, Army Medical University, Chongqing, China.,Department of Nursing Psychology, Army Medical University, Chongqing, China
| |
Collapse
|
3
|
Diering GH. Remembering and forgetting in sleep: Selective synaptic plasticity during sleep driven by scaling factors Homer1a and Arc. Neurobiol Stress 2022; 22:100512. [PMID: 36632309 PMCID: PMC9826981 DOI: 10.1016/j.ynstr.2022.100512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 12/01/2022] [Accepted: 12/29/2022] [Indexed: 01/02/2023] Open
Abstract
Sleep is a conserved and essential process that supports learning and memory. Synapses are a major target of sleep function and a locus of sleep need. Evidence in the literature suggests that the need for sleep has a cellular or microcircuit level basis, and that sleep need can accumulate within localized brain regions as a function of waking activity. Activation of sleep promoting kinases and accumulation of synaptic phosphorylation was recently shown to be part of the molecular basis for the localized sleep need. A prominent hypothesis in the field suggests that some benefits of sleep are mediated by a broad but selective weakening, or scaling-down, of synaptic strength during sleep in order to offset increased excitability from synaptic potentiation during wake. The literature also shows that synapses can be strengthened during sleep, raising the question of what molecular mechanisms may allow for selection of synaptic plasticity types during sleep. Here I describe mechanisms of action of the scaling factors Arc and Homer1a in selective plasticity and links with sleep need. Arc and Homer1a are induced in neurons in response to waking neuronal activity and accumulate with time spent awake. I suggest that during sleep, Arc and Homer1a drive broad weakening of synapses through homeostatic scaling-down, but in a manner that is sensitive to the plasticity history of individual synapses, based on patterned phosphorylation of synaptic proteins. Therefore, Arc and Homer1a may offer insights into the intricate links between a cellular basis of sleep need and memory consolidation during sleep.
Collapse
Affiliation(s)
- Graham H. Diering
- Department of Cell Biology and Physiology and the UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA,Carolina Institute for Developmental Disabilities, USA,111 Mason Farm Road, 5200 Medical and Biomolecular Research Building, Chapel Hill, NC, 27599-7545, USA.
| |
Collapse
|
4
|
Dixon-Melvin R, Shanazz K, Nalloor R, Bunting KM, Vazdarjanova A. Emotional state alters encoding of long-term spatial episodic memory. Neurobiol Learn Mem 2022; 187:107562. [PMID: 34848328 PMCID: PMC9413022 DOI: 10.1016/j.nlm.2021.107562] [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: 04/05/2021] [Revised: 08/19/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023]
Abstract
The neurobiology of emotion and episodic memory are well-researched subjects, as is their intersection: memory of emotional events (i.e. emotional memory). We and others have previously demonstrated that the emotional valence of stimuli is encoded in the dorsal hippocampus, a structure integral to the acquisition, consolidation and retrieval of long-term episodic memories. Such findings are consistent with the idea that the emotional valence of stimuli contributes to the "what" component of episodic memories ("where" and "when" being the other components). We hypothesized that being in a heightened emotional state by itself does not contribute to the "what" component of episodic memories. We tested an inference of this hypothesis - that negative emotional state does not alter re-encoding of a spatial episodic event. Rats from the experimental group explored a novel place at their baseline emotional state (Event 1) and 20 min later re-explored the same place (Event 2) in a negative emotional state induced by a state-altering event prior to Event 2. We examined neuronal ensembles that induced expression of Arc and Homer1a, two immediate-early genes (IEGs) necessary for synaptic plasticity and consolidation of long-term memories, during both events. We found that in dorsal CA1 and dorsal CA3, Event 1 and Event 2 induced IEG expression in different neuronal ensembles. This finding was reflected in a low Fidelity score, which assesses the percentage of the Event 1 IEG-expressing ensemble re-activated during Event 2. The Fidelity score was significantly higher in a control group which was at a baseline emotional state during Event 2. Groups which were matched for non-specific disruptions from the state-altering event had intermediate Fidelity scores in dorsal CA1. The Fidelity scores of the dorsal CA3 in the latter groups were similar to those of the control group. Combined, the findings reject the tested hypothesis and suggest that a negative emotional state is encoded in the hippocampus as part of the long-term memory of episodic events that lack explicit emotion-inducing stimuli. These findings also suggest that individuals who often experience strong negative emotional states incorporate these states into ongoing non-emotional episodic memories.
Collapse
Affiliation(s)
- Rachael Dixon-Melvin
- Charlie Norwood VAMC, Augusta GA,Department of Pharmacology & Toxicology, MCG, Augusta University, Augusta GA
| | - Khadijah Shanazz
- Charlie Norwood VAMC, Augusta GA,Department of Pharmacology & Toxicology, MCG, Augusta University, Augusta GA
| | - Rebecca Nalloor
- Charlie Norwood VAMC, Augusta GA,Department of Pharmacology & Toxicology, MCG, Augusta University, Augusta GA
| | - Kristopher M. Bunting
- Charlie Norwood VAMC, Augusta GA,Department of Pharmacology & Toxicology, MCG, Augusta University, Augusta GA
| | - Almira Vazdarjanova
- Charlie Norwood VAMC, Augusta GA,Department of Pharmacology & Toxicology, MCG, Augusta University, Augusta GA,Corresponding Author: Almira Vazdarjanova, , Charlie Norwood VAMC and Augusta University, 1 Freedom Way, DD 6B110, Augusta GA 30904, USA
| |
Collapse
|
5
|
Membrane trafficking and positioning of mGluRs at presynaptic and postsynaptic sites of excitatory synapses. Neuropharmacology 2021; 200:108799. [PMID: 34592242 DOI: 10.1016/j.neuropharm.2021.108799] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/31/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The plethora of functions of glutamate in the brain are mediated by the complementary actions of ionotropic and metabotropic glutamate receptors (mGluRs). The ionotropic glutamate receptors carry most of the fast excitatory transmission, while mGluRs modulate transmission on longer timescales by triggering multiple intracellular signaling pathways. As such, mGluRs mediate critical aspects of synaptic transmission and plasticity. Interestingly, at synapses, mGluRs operate at both sides of the cleft, and thus bidirectionally exert the effects of glutamate. At postsynaptic sites, group I mGluRs act to modulate excitability and plasticity. At presynaptic sites, group II and III mGluRs act as auto-receptors, modulating release properties in an activity-dependent manner. Thus, synaptic mGluRs are essential signal integrators that functionally couple presynaptic and postsynaptic mechanisms of transmission and plasticity. Understanding how these receptors reach the membrane and are positioned relative to the presynaptic glutamate release site are therefore important aspects of synapse biology. In this review, we will discuss the currently known mechanisms underlying the trafficking and positioning of mGluRs at and around synapses, and how these mechanisms contribute to synaptic functioning. We will highlight outstanding questions and present an outlook on how recent technological developments will move this exciting research field forward.
Collapse
|
6
|
Bockaert J, Perroy J, Ango F. The Complex Formed by Group I Metabotropic Glutamate Receptor (mGluR) and Homer1a Plays a Central Role in Metaplasticity and Homeostatic Synaptic Scaling. J Neurosci 2021; 41:5567-5578. [PMID: 34193623 PMCID: PMC8244974 DOI: 10.1523/jneurosci.0026-21.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/28/2022] Open
Abstract
G-protein-coupled receptors can be constitutively activated following physical interaction with intracellular proteins. The first example described was the constitutive activation of Group I metabotropic glutamate receptors (mGluR: mGluR1,5) following their interaction with Homer1a, an activity-inducible early-termination variant of the scaffolding protein Homer that lacks dimerization capacity (Ango et al., 2001). Homer1a disrupts the links, maintained by the long form of Homer (cross-linking Homers), between mGluR1,5 and the Shank-GKAP-PSD-95-ionotropic glutamate receptor network. Two characteristics of the constitutive activation of the Group I mGluR-Homer1a complex are particularly interesting: (1) it affects a large number of synapses in which Homer1a is upregulated following enhanced, long-lasting neuronal activity; and (2) it mainly depends on Homer1a protein turnover. The constitutively active Group I mGluR-Homer1a complex is involved in the two main forms of non-Hebbian neuronal plasticity: "metaplasticity" and "homeostatic synaptic scaling," which are implicated in a large series of physiological and pathologic processes. Those include non-Hebbian plasticity observed in visual system, synapses modulated by addictive drugs (rewarded synapses), chronically overactivated synaptic networks, normal sleep, and sleep deprivation.
Collapse
Affiliation(s)
- Joël Bockaert
- Institut de Génomique Fonctionnelle, Université Montpellier, Center National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 34094 Montpellier, France
| | - Julie Perroy
- Institut de Génomique Fonctionnelle, Université Montpellier, Center National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 34094 Montpellier, France
| | - Fabrice Ango
- Institut des Neurosciences de Montpellier, Université Montpellier, Center National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 34295 Montpellier, France
| |
Collapse
|
7
|
Bockaert J, Bécamel C, Chaumont-Dubel S, Claeysen S, Vandermoere F, Marin P. Novel and atypical pathways for serotonin signaling. Fac Rev 2021; 10:52. [PMID: 34195691 PMCID: PMC8204760 DOI: 10.12703/r/10-52] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Serotonin (5-HT) appeared billions of years before 5-HT receptors and synapses. It is thus not surprising that 5-HT can control biological processes independently of its receptors. One example is serotonylation, which consists of covalent binding of 5-HT to the primary amine of glutamine. Over the past 20 years, serotonylation has been involved in the regulation of many signaling mechanisms. One of the most striking examples is the recent evidence that serotonylation of histone H3 constitutes an epigenetic mark. However, the pathophysiological role of histone H3 serotonylation remains to be discovered. All but one of the 5-HT receptors are G-protein-coupled receptors (GPCRs). The signaling pathways they control are finely tuned, and new, unexpected regulatory mechanisms are being uncovered continuously. Some 5-HT receptors (5-HT2C, 5-HT4, 5-HT6, and 5-HT7) signal through mechanisms that require neither G-proteins nor β-arrestins, the two classical and almost universal GPCR signal transducers. 5-HT6 receptors are constitutively activated via their association with intracellular GPCR-interacting proteins (GIPs), including neurofibromin 1, cyclin-dependent kinase 5 (Cdk5), and G-protein-regulated inducer of neurite outgrowth 1 (GPRIN1). Interactions of 5-HT6 receptor with Cdk5 and GPRIN1 are not concomitant but occur sequentially and play a key role in dendritic tree morphogenesis. Furthermore, 5-HT6 receptor-mediated G-protein signaling in neurons is different in the cell body and primary cilium, where it is modulated by smoothened receptor activation. Finally, 5-HT2A receptors form heteromers with mGlu2 metabotropic glutamate receptors. This heteromerization results in a specific phosphorylation of mGlu2 receptor on a serine residue (Ser843) upon agonist stimulation of 5-HT2A or mGlu2 receptor. mGlu2 receptor phosphorylation on Ser843 is an essential step in engagement of Gi/o signaling not only upon mGlu2 receptor activation but also following 5-HT2A receptor activation, and thus represents a key molecular event underlying functional crosstalk between both receptors.
Collapse
Affiliation(s)
- Joël Bockaert
- The Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Carine Bécamel
- The Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Séverine Chaumont-Dubel
- The Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Sylvie Claeysen
- The Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Franck Vandermoere
- The Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Philippe Marin
- The Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| |
Collapse
|
8
|
Abstract
Methamphetamine abuse leads to devastating consequences, including addiction, crime, and death. Despite decades of research, no medication has been approved by the U.S. Food and Drug Administration for the treatment of Methamphetamine Use Disorder. Thus, there is a need for new therapeutic approaches. Animal studies demonstrate that methamphetamine exposure dysregulates forebrain function involving the Group-I metabotropic glutamate receptor subtype 5 (mGlu5), which is predominantly localized to postsynaptic sites. Allosteric modulators of mGlu5 offer a unique opportunity to modulate glutamatergic neurotransmission selectively, thereby potentially ameliorating methamphetamine-induced disruptions. Negative allosteric modulators of mGlu5 attenuate the effects of methamphetamine, including rewarding/reinforcing properties of the drug across animal models, and have shown promising effects in clinical trials for Anxiety Disorder and Major Depressive Disorder. Preclinical studies have also sparked great interest in mGlu5 positive allosteric modulators, which exhibit antipsychotic and anxiolytic properties, and facilitate extinction learning when access to methamphetamine is removed, possibly via the amelioration of methamphetamine-induced cognitive deficits. Clinical research is now needed to elucidate the mechanisms underlying the mGlu5 receptor-related effects of methamphetamine and the contributions of these effects to addictive behaviors. The growing array of mGlu5 allosteric modulators provides excellent tools for this purpose and may offer the prospect of developing tailored and effective medications for Methamphetamine Use Disorder.
Collapse
|
9
|
Kuhn M, Maier JG, Wolf E, Mainberger F, Feige B, Maywald S, Bredl A, Michel M, Sendelbach N, Normann C, Klöppel S, Eckert A, Riemann D, Nissen C. Indices of cortical plasticity after therapeutic sleep deprivation in patients with major depressive disorder. J Affect Disord 2020; 277:425-435. [PMID: 32866801 DOI: 10.1016/j.jad.2020.08.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/02/2020] [Accepted: 08/20/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND Therapeutic sleep deprivation (SD) presents a unique paradigm to study the neurobiology of major depressive disorder (MDD). However, the rapid antidepressant mechanism, which differs from today's slow first-line treatments, is not sufficiently understood. We recently integrated two prominent hypotheses of MDD and sleep, the synaptic plasticity hypothesis of MDD and the synaptic homeostasis hypothesis of sleep-wake regulation, into a synaptic plasticity model of therapeutic SD in MDD. Here, we further tested this model positing that homeostatically elevating net synaptic strength through therapeutic SD shifts the initially deficient inducibility of associative synaptic long-term potentiation (LTP)-like plasticity in patients with MDD into a more favorable window of associative plasticity. METHODS We used paired associative stimulation (PAS), a transcranial magnetic stimulation protocol (TMS), to quantify cortical LTP-like plasticity after one night of therapeutic sleep deprivation in 28 patients with MDD. RESULTS We demonstrate a significantly different inducibility of associative plasticity in clinical responders to therapeutic SD (> 50% improvement on the 6-item Hamilton-Rating-Scale for Depression, n=13) compared to non-responders (n=15), which was driven by a long-term depression (LTD)-like response in SD-non-responders. Indices of global net synaptic strength (wake EEG theta activity, intracortical inhibition and BDNF serum levels) were increased after SD in both groups, with responders showing a generally lower intracortical inhibition than non-responders. LIMITATIONS Repetitive assessments prior to and after treatment would be needed to further determine potential mechanisms. CONCLUSION After a night of therapeutic SD, clinical responders show a significantly higher inducibility of associative LTP-like plasticity than non-responders.
Collapse
Affiliation(s)
- Marion Kuhn
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Jonathan G Maier
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Elias Wolf
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Florian Mainberger
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Bernd Feige
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Sarah Maywald
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Aliza Bredl
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Maike Michel
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Nicola Sendelbach
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Claus Normann
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Stefan Klöppel
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Anne Eckert
- Neurobiology Lab for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular & Cognitive Neuroscience, University of Basel, Basel, Switzerland; Psychiatric University Clinics, University of Basel, Basel, Switzerland
| | - Dieter Riemann
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Christoph Nissen
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland.
| |
Collapse
|
10
|
Piva A, Caffino L, Padovani L, Pintori N, Mottarlini F, Sferrazza G, Paolone G, Fumagalli F, Chiamulera C. The metaplastic effects of ketamine on sucrose renewal and contextual memory reconsolidation in rats. Behav Brain Res 2020; 379:112347. [DOI: 10.1016/j.bbr.2019.112347] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/06/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022]
|
11
|
Chokshi V, Gao M, Grier BD, Owens A, Wang H, Worley PF, Lee HK. Input-Specific Metaplasticity in the Visual Cortex Requires Homer1a-Mediated mGluR5 Signaling. Neuron 2019; 104:736-748.e6. [PMID: 31563294 DOI: 10.1016/j.neuron.2019.08.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 06/24/2019] [Accepted: 08/09/2019] [Indexed: 11/17/2022]
Abstract
Effective sensory processing depends on sensory experience-dependent metaplasticity, which allows homeostatic maintenance of neural network activity and preserves feature selectivity. Following a strong increase in sensory drive, plasticity mechanisms that decrease the strength of excitatory synapses are preferentially engaged to maintain stability in neural networks. Such adaptation has been demonstrated in various model systems, including mouse primary visual cortex (V1), where excitatory synapses on layer 2/3 (L2/3) neurons undergo rapid reduction in strength when visually deprived mice are reexposed to light. Here, we report that this form of plasticity is specific to intracortical inputs to V1 L2/3 neurons and depends on the activity of NMDA receptors (NMDARs) and group I metabotropic glutamate receptor 5 (mGluR5). Furthermore, we found that expression of the immediate early gene (IEG) Homer1a (H1a) and its subsequent interaction with mGluR5s are necessary for this input-specific metaplasticity.
Collapse
Affiliation(s)
- Varun Chokshi
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; Cell Molecular Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ming Gao
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bryce D Grier
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Ashley Owens
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Hui Wang
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Paul F Worley
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Hey-Kyoung Lee
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; Cell Molecular Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21218, USA.
| |
Collapse
|
12
|
Laat B, Weerasekera A, Leurquin‐Sterk G, Gsell W, Bormans G, Himmelreich U, Casteels C, Van Laere K. Effects of alcohol exposure on the glutamatergic system: a combined longitudinal 18 F-FPEB and 1 H-MRS study in rats. Addict Biol 2019; 24:696-706. [PMID: 29790622 DOI: 10.1111/adb.12635] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 03/06/2018] [Accepted: 04/18/2018] [Indexed: 12/17/2022]
Abstract
In a longitudinal rat model of alcohol consumption, we showed that exposure to alcohol decreased the concentration of glutamate in the prefrontal cortex, whereas a normalization occurred during abstinence. 18F-FPEB PET scans revealed that pre-exposure mGluR5 availability in the nucleus accumbens was associated with future alcohol preference. Finally, alcohol exposure induced a decrease in mGluR5 availability in the bilateral hippocampus and amygdala compared with baseline, and in the hippocampus and striatum compared with saccharin (Figure).
Collapse
Affiliation(s)
- Bart Laat
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven/University Hospital Leuven, Division of Nuclear MedicineDepartment of Imaging and Pathology Belgium
| | - Akila Weerasekera
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven, Biomedical MRI unitDepartment of Imaging and Pathology Belgium
| | - Gil Leurquin‐Sterk
- KU Leuven – University of Leuven/University Hospital Leuven, Division of Nuclear MedicineDepartment of Imaging and Pathology Belgium
| | - Willy Gsell
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven, Biomedical MRI unitDepartment of Imaging and Pathology Belgium
| | - Guy Bormans
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven, Laboratory for RadiopharmacyDepartment of Pharmaceutical and Pharmacological Sciences Belgium
| | - Uwe Himmelreich
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven, Biomedical MRI unitDepartment of Imaging and Pathology Belgium
| | - Cindy Casteels
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven/University Hospital Leuven, Division of Nuclear MedicineDepartment of Imaging and Pathology Belgium
| | - Koen Van Laere
- KU Leuven – University of Leuven, MoSAICMolecular Small Animal Imaging Center Belgium
- KU Leuven – University of Leuven/University Hospital Leuven, Division of Nuclear MedicineDepartment of Imaging and Pathology Belgium
| |
Collapse
|
13
|
Neuhofer D, Kalivas P. Metaplasticity at the addicted tetrapartite synapse: A common denominator of drug induced adaptations and potential treatment target for addiction. Neurobiol Learn Mem 2018; 154:97-111. [PMID: 29428364 PMCID: PMC6112115 DOI: 10.1016/j.nlm.2018.02.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/26/2018] [Accepted: 02/07/2018] [Indexed: 11/22/2022]
Abstract
In light of the current worldwide addiction epidemic, the need for successful therapies is more urgent than ever. Although we made substantial progress in our basic understanding of addiction, reliable therapies are lacking. Since 40-60% of patients treated for substance use disorder return to active substance use within a year following treatment discharge, alleviating the vulnerability to relapse is regarded as the most promising avenue for addiction therapy. Preclinical addiction research often focuses on maladaptive synaptic plasticity within the reward pathway. However, drug induced neuroadaptations do not only lead to a strengthening of distinct drug associated cues and drug conditioned behaviors, but also seem to increase plasticity thresholds for environmental stimuli that are not associated with the drug. This form of higher order plasticity, or synaptic metaplasticity, is not expressed as a change in the efficacy of synaptic transmission but as a change in the direction or degree of plasticity induced by a distinct stimulation pattern. Experimental addiction research has demonstrated metaplasticity after exposure to multiple classes of addictive drugs. In this review we will focus on the concept of synaptic metaplasticity in the context of preclinical addiction research. We will take a closer look at the tetrapartite glutamatergic synapse and outline forms of metaplasticity that have been described at the addicted synapse. Finally we will discuss the different potential avenues for pharmacotherapies that target glutamatergic synaptic plasticity and metaplasticity. Here we will argue that aberrant metaplasticity renders the reward seeking circuitry more rigid and hence less able to adapt to changing environmental contingencies. An understanding of the molecular mechanisms that underlie this metaplasticity is crucial for the development of new strategies for addiction therapy. The correction of drug-induced metaplasticity could be used to support behavioral and pharmacotherapies for the treatment of addiction.
Collapse
Affiliation(s)
- Daniela Neuhofer
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, United States.
| | - Peter Kalivas
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, United States
| |
Collapse
|
14
|
Piva A, Gerace E, Di Chio M, Osanni L, Padovani L, Caffino L, Fumagalli F, Pellegrini-Giampietro DE, Chiamulera C. The metaplastic effects of NMDA receptors blockade on reactivation of instrumental memories in rats. Neurobiol Learn Mem 2018; 154:87-96. [DOI: 10.1016/j.nlm.2018.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 01/15/2018] [Accepted: 01/21/2018] [Indexed: 10/18/2022]
|
15
|
Mayhew J, Graham BA, Biber K, Nilsson M, Walker FR. Purinergic modulation of glutamate transmission: An expanding role in stress-linked neuropathology. Neurosci Biobehav Rev 2018; 93:26-37. [PMID: 29959963 DOI: 10.1016/j.neubiorev.2018.06.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/18/2018] [Accepted: 06/24/2018] [Indexed: 02/04/2023]
Abstract
Chronic stress has been extensively linked to disturbances in glutamatergic signalling. Emerging from this field of research is a considerable number of studies identifying the ability of purines at the pre-, post-, and peri-synaptic levels to tune glutamatergic neurotransmission. While the evidence describing purinergic control of glutamate has continued to grow, there has been relatively little attention given to how chronic stress modulates purinergic functions. The available research on this topic has demonstrated that chronic stress can not only disturb purinergic receptors involved in the regulation of glutamate neurotransmission, but also perturb glial-dependent purinergic signalling. This review will provide a detailed examining of the complex literature relating to glutamatergic-purinergic interactions with a focus on both neuronal and glial contributions. Once these detailed interactions have been described and contextualised, we will integrate recent findings from the field of stress research.
Collapse
Affiliation(s)
- J Mayhew
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia.
| | - B A Graham
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - K Biber
- Department of Psychiatry and Psychotherapy, University Hospital Freiburg, 79104 Freiburg, Germany; Department of Neuroscience, University Medical Center Groningen, University of Groningen, 9713 AV Groningen, The Netherlands
| | - M Nilsson
- Centre for Translational Neuroscience and Mental Health Research, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - F R Walker
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| |
Collapse
|
16
|
Recent insights into antidepressant therapy: Distinct pathways and potential common mechanisms in the treatment of depressive syndromes. Neurosci Biobehav Rev 2018; 88:63-72. [DOI: 10.1016/j.neubiorev.2018.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 02/07/2018] [Accepted: 03/13/2018] [Indexed: 12/13/2022]
|
17
|
Datko MC, Hu JH, Williams M, Reyes CM, Lominac KD, von Jonquieres G, Klugmann M, Worley PF, Szumlinski KK. Behavioral and Neurochemical Phenotyping of Mice Incapable of Homer1a Induction. Front Behav Neurosci 2017; 11:208. [PMID: 29163080 PMCID: PMC5672496 DOI: 10.3389/fnbeh.2017.00208] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/12/2017] [Indexed: 11/18/2022] Open
Abstract
Immediate early and constitutively expressed products of the Homer1 gene regulate the functional assembly of post-synaptic density proteins at glutamatergic synapses to influence excitatory neurotransmission and synaptic plasticity. Earlier studies of Homer1 gene knock-out (KO) mice indicated active, but distinct, roles for IEG and constitutively expressed Homer1 gene products in regulating cognitive, emotional, motivational and sensorimotor processing, as well as behavioral and neurochemical sensitivity to cocaine. More recent characterization of transgenic mice engineered to prevent generation of the IEG form (a.k.a Homer1a KO) pose a critical role for Homer1a in cocaine-induced behavioral and neurochemical sensitization of relevance to drug addiction and related neuropsychiatric disorders. Here, we extend our characterization of the Homer1a KO mouse and report a modest pro-depressant phenotype, but no deleterious effects of the KO upon spatial learning/memory, prepulse inhibition, or cocaine-induced place-conditioning. As we reported previously, Homer1a KO mice did not develop cocaine-induced behavioral or neurochemical sensitization within the nucleus accumbens; however, virus-mediated Homer1a over-expression within the nucleus accumbens reversed the sensitization phenotype of KO mice. We also report several neurochemical abnormalities within the nucleus accumbens of Homer1a KO mice that include: elevated basal dopamine and reduced basal glutamate content, Group1 mGluR agonist-induced glutamate release and high K+-stimulated release of dopamine and glutamate within this region. Many of the neurochemical anomalies exhibited by Homer1a KO mice are recapitulated upon deletion of the entire Homer1 gene; however, Homer1 deletion did not affect NAC dopamine or alter K+-stimulated neurotransmitter release within this region. These data show that the selective deletion of Homer1a produces a behavioral and neurochemical phenotype that is distinguishable from that produced by deletion of the entire Homer1 gene. Moreover, the data indicate a specific role for Homer1a in regulating cocaine-induced behavioral and neurochemical sensitization of potential relevance to the psychotogenic properties of this drug.
Collapse
Affiliation(s)
- Michael C Datko
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Jia-Hua Hu
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Melanie Williams
- Department of Molecular, Developmental and Cell Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Cindy M Reyes
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Kevin D Lominac
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Georg von Jonquieres
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Paul F Worley
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States.,Department of Molecular, Developmental and Cell Biology, University of California, Santa Barbara, Santa Barbara, CA, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| |
Collapse
|
18
|
Parkin Deficiency Reduces Hippocampal Glutamatergic Neurotransmission by Impairing AMPA Receptor Endocytosis. J Neurosci 2017; 36:12243-12258. [PMID: 27903732 DOI: 10.1523/jneurosci.1473-16.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 09/19/2016] [Accepted: 10/18/2016] [Indexed: 12/20/2022] Open
Abstract
Mutations in the gene encoding Parkin, an E3 ubiquitin ligase, lead to juvenile-onset Parkinson's disease by inducing the selective death of midbrain dopaminergic neurons. Accumulating evidence indicates that Parkin also has an important role in excitatory glutamatergic neurotransmission, although its precise mechanism of action remains unclear. Here, we investigate Parkin's role at glutamatergic synapses of rat hippocampal neurons. We find that Parkin-deficient neurons exhibit significantly reduced AMPA receptor (AMPAR)-mediated currents and cell-surface expression, and that these phenotypes result from decreased postsynaptic expression of the adaptor protein Homer1, which is necessary for coupling AMPAR endocytic zones with the postsynaptic density. Accordingly, Parkin loss of function leads to the reduced density of postsynaptic endocytic zones and to impaired AMPAR internalization. These findings demonstrate a novel and essential role for Parkin in glutamatergic neurotransmission, as a stabilizer of postsynaptic Homer1 and the Homer1-linked endocytic machinery necessary for maintaining normal cell-surface AMPAR levels. SIGNIFICANCE STATEMENT Mutations in Parkin, a ubiquitinating enzyme, lead to the selective loss of midbrain dopaminergic neurons and juvenile-onset Parkinson's disease (PD). Parkin loss of function has also been shown to alter hippocampal glutamatergic neurotransmission, providing a potential explanation for PD-associated cognitive impairment. However, very little is known about Parkin's specific sites or mechanisms of action at glutamatergic synapses. Here, we show that Parkin deficiency leads to decreased AMPA receptor-mediated activity due to disruption of the postsynaptic endocytic zones required for maintaining proper cell-surface AMPA receptor levels. These findings demonstrate a novel role for Parkin in synaptic AMPA receptor internalization and suggest a Parkin-dependent mechanism for hippocampal dysfunction that may explain cognitive deficits associated with some forms of PD.
Collapse
|
19
|
Chiamulera C, Marzo CM, Balfour DJK. Metabotropic glutamate receptor 5 as a potential target for smoking cessation. Psychopharmacology (Berl) 2017; 234:1357-1370. [PMID: 27847973 DOI: 10.1007/s00213-016-4487-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/07/2016] [Indexed: 12/21/2022]
Abstract
RATIONALE Most habitual smokers find it difficult to quit smoking because they are dependent upon the nicotine present in tobacco smoke. Tobacco dependence is commonly treated pharmacologically using nicotine replacement therapy or drugs, such as varenicline, that target the nicotinic receptor. Relapse rates, however, remain high, and there remains a need to develop novel non-nicotinic pharmacotherapies for the dependence that are more effective than existing treatments. OBJECTIVE The purpose of this paper is to review the evidence from preclinical and clinical studies that drugs that antagonise the metabotropic glutamate receptor 5 (mGluR5) in the brain are likely to be efficacious as treatments for tobacco dependence. RESULTS Imaging studies reveal that chronic exposure to tobacco smoke reduces the density of mGluR5s in human brain. Preclinical results demonstrate that negative allosteric modulators (NAMs) at mGluR5 attenuate both nicotine self-administration and the reinstatement of responding evoked by exposure to conditioned cues paired with nicotine delivery. They also attenuate the effects of nicotine on brain dopamine pathways implicated in addiction. CONCLUSIONS Although mGluR5 NAMs attenuate most of the key facets of nicotine dependence, they potentiate the symptoms of nicotine withdrawal. This may limit their value as smoking cessation aids. The NAMs that have been employed most widely in preclinical studies of nicotine dependence have too many "off-target" effects to be used clinically. However, newer mGluR5 NAMs have been developed for clinical use in other indications. Future studies will determine if these agents can also be used effectively and safely to treat tobacco dependence.
Collapse
Affiliation(s)
- Cristiano Chiamulera
- Neuropsychopharmacology Lab., Section Pharmacology, Department Diagnostic and Public Health, University of Verona, P.le Scuro 10, 37134, Verona, Italy.
| | - Claudio Marcello Marzo
- Neuropsychopharmacology Lab., Section Pharmacology, Department Diagnostic and Public Health, University of Verona, P.le Scuro 10, 37134, Verona, Italy
| | - David J K Balfour
- Division of Neuroscience, University of Dundee Medical School, Mailbox 6, Ninewells Hospital, Dundee, DD1 9SY, UK
| |
Collapse
|