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Feng YF, Zhou YY, Duan KM. The Role of Extrasynaptic GABA Receptors in Postpartum Depression. Mol Neurobiol 2024; 61:385-396. [PMID: 37612480 DOI: 10.1007/s12035-023-03574-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/11/2023] [Indexed: 08/25/2023]
Abstract
Postpartum depression is a serious disease with a high incidence and severe impact on pregnant women and infants, but its mechanism remains unclear. Recent studies have shown that GABA receptors, especially extrasynaptic receptors, are closely associated with postpartum depression. There are many different structures of GABA receptors, so different types of receptors have different functions, even though they transmit information primarily through GABA. In this review, we focus on the function of GABA receptors, especially extrasynaptic GABA receptors, and their association with postpartum depression. We have shown that the extrasynaptic GABA receptor has a significant impact on the activity and function of neurons through tonic inhibition. The extrasynaptic receptor and its ligands undergo drastic changes during pregnancy and childbirth. Abnormal changes or the body's inability to adjust and recover may be an important cause of postpartum depression. Finally, by reviewing the mechanisms of several novel antidepressants, we suggest that extrasynaptic receptors may be potential targets for the treatment of postpartum depression.
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Affiliation(s)
- Yun Fei Feng
- Third Xiangya Hospital of Central South University, Changsha, 410013, China
| | - Yin Yong Zhou
- Third Xiangya Hospital of Central South University, Changsha, 410013, China
| | - Kai Ming Duan
- Third Xiangya Hospital of Central South University, Changsha, 410013, China.
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2
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Honoré È, Belo do Nascimento I, Laplante I, Lacaille JC. Stimulation of protein synthesis by optogenetic and chemical induction of excitatory synaptic plasticity in hippocampal somatostatin interneurons. Mol Brain 2022; 15:81. [PMID: 36123709 PMCID: PMC9484204 DOI: 10.1186/s13041-022-00967-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/09/2022] [Indexed: 11/22/2022] Open
Abstract
Somatostatin-expressing interneurons (SOM-INs) are a major subpopulation of GABAergic cells in CA1 hippocampus that receive excitation from pyramidal cells (PCs) and provide feedback control of synaptic inputs onto PC dendrites. Excitatory synapses from PCs onto SOM-INs (PC-SOM synapses) exhibit long-term potentiation (LTP) mediated by type 1a metabotropic glutamate receptors (mGluR1a). LTP at PC-SOM synapses translates in lasting regulation of metaplasticity of entorhinal and CA3 synaptic inputs on PCs and contributes to hippocampus-dependent learning. A persistent form of PC-SOM synapse LTP lasting hours is prevented by blockers of transcription and translation, and a more transient form of PC-SOM synapse LTP lasting tens of minutes requires mTORC1-signaling, suggesting an involvement of protein synthesis. However, the role of protein synthesis in these forms of plasticity has not been directly demonstrated. Here we use the SUrface SEnsing of Translation (SUnSET) assay of protein synthesis to directly show that the induction protocols for both forms of LTP at PC-SOM synapses stimulate protein synthesis in SOM-INs. Moreover, protein synthesis stimulated by persistent LTP induction was prevented in mice with a SOM-IN conditional knock-out of Raptor, an essential component of mTORC1, indicating a critical role of mTORC1 in the control of translation in PC-SOM synapse plasticity. Moreover, protein synthesis induced by both forms of LTP may share common mechanisms as transient LTP induction occluded further stimulation of protein synthesis by persistent LTP induction. Our findings highlight a crucial role of protein synthesis and its control by mTORC1 in SOM-INs that is important for hippocampus-dependent memory function.
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Affiliation(s)
- Ève Honoré
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on Neural Signaling and Circuits, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada
| | - Inês Belo do Nascimento
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on Neural Signaling and Circuits, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada
| | - Isabel Laplante
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on Neural Signaling and Circuits, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada
| | - Jean-Claude Lacaille
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on Neural Signaling and Circuits, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada.
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3
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Khlaifia A, Honoré E, Artinian J, Laplante I, Lacaille JC. mTORC1 function in hippocampal parvalbumin interneurons: regulation of firing and long-term potentiation of intrinsic excitability but not long-term contextual fear memory and context discrimination. Mol Brain 2022; 15:56. [PMID: 35715811 PMCID: PMC9204956 DOI: 10.1186/s13041-022-00941-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/07/2022] [Indexed: 02/03/2023] Open
Abstract
Hippocampal CA1 parvalbumin-expressing interneurons (PV INs) play a central role in controlling principal cell activity and orchestrating network oscillations. PV INs receive excitatory inputs from CA3 Schaffer collaterals and local CA1 pyramidal cells, and they provide perisomatic inhibition. Schaffer collateral excitatory synapses onto PV INs express Hebbian and anti-Hebbian types of long-term potentiation (LTP), as well as elicit LTP of intrinsic excitability (LTPIE). LTPIE requires the activation of type 5 metabotropic glutamate receptors (mGluR5) and is mediated by downregulation of potassium channels Kv1.1. It is sensitive to rapamycin and thus may involve activation of the mammalian target of rapamycin complex 1 (mTORC1). LTPIE facilitates PV INs recruitment in CA1 and maintains an excitatory-inhibitory balance. Impaired CA1 PV INs activity or LTP affects network oscillations and memory. However, whether LTPIE in PV INs plays a role in hippocampus-dependent memory remains unknown. Here, we used conditional deletion of the obligatory component of mTORC1, the Regulatory-Associated Protein of mTOR (Raptor), to directly manipulate mTORC1 in PV INs. We found that homozygous, but not heterozygous, conditional knock-out of Rptor resulted in a decrease in CA1 PV INs of mTORC1 signaling via its downstream effector S6 phosphorylation assessed by immunofluorescence. In whole-cell recordings from hippocampal slices, repetitive firing of CA1 PV INs was impaired in mice with either homozygous or heterozygous conditional knock-out of Rptor. High frequency stimulation of Schaffer collateral inputs that induce LTPIE in PV INs of control mice failed to do so in mice with either heterozygous or homozygous conditional knock-out of Rptor in PV INs. At the behavioral level, mice with homozygous or heterozygous conditional knock-out of Rptor showed similar long-term contextual fear memory or contextual fear memory discrimination relative to control mice. Thus, mTORC1 activity in CA1 PV INs regulates repetitive firing and LTPIE but not consolidation of long-term contextual fear memory and context discrimination. Our results indicate that mTORC1 plays cell-specific roles in synaptic plasticity of hippocampal inhibitory interneurons that are differentially involved in hippocampus-dependent learning and memory.
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Affiliation(s)
- Abdessattar Khlaifia
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group On Neural Signaling and Circuitry (GRSNC), Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada.,Department of Psychology, University of Toronto Scarborough, ON, M1C1A4, Toronto, Canada
| | - Eve Honoré
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group On Neural Signaling and Circuitry (GRSNC), Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada
| | - Julien Artinian
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group On Neural Signaling and Circuitry (GRSNC), Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada.,NeuroService, Neurocentre Magendie , Bordeaux, France
| | - Isabel Laplante
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group On Neural Signaling and Circuitry (GRSNC), Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group On Neural Signaling and Circuitry (GRSNC), Université de Montréal, P.O. Box 6128, Station Downtown, QC, H3C 3J7, Montreal, Canada.
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4
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Racine AS, Michon FX, Laplante I, Lacaille JC. Somatostatin contributes to long-term potentiation at excitatory synapses onto hippocampal somatostatinergic interneurons. Mol Brain 2021; 14:130. [PMID: 34429141 PMCID: PMC8385910 DOI: 10.1186/s13041-021-00830-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/13/2021] [Indexed: 04/13/2023] Open
Abstract
Somatostatin-expressing interneurons (SOM-INs) are a major subpopulation of GABAergic cells in CA1 hippocampus that receive excitation from pyramidal cells (PCs), and, in turn, provide feedback inhibition onto PC dendrites. Excitatory synapses onto SOM-INs show a Hebbian long-term potentiation (LTP) mediated by type 1a metabotropic glutamate receptors (mGluR1a) that is implicated in hippocampus-dependent learning. The neuropeptide somatostatin (SST) is also critical for hippocampal long-term synaptic plasticity, as well as learning and memory. SST effects on hippocampal PCs are well documented, but its actions on inhibitory interneurons remain largely undetermined. In the present work, we investigate the involvement of SST in long-term potentiation of CA1 SOM-IN excitatory synapses using pharmacological approaches targeting the somatostatinergic system and whole cell recordings in slices from transgenic mice expressing eYFP in SOM-INs. We report that application of exogenous SST14 induces long-term potentiation of excitatory postsynaptic potentials in SOM-INs via somatostatin type 1–5 receptors (SST1-5Rs) but does not affect synapses of PC or parvalbumin-expressing interneurons. Hebbian LTP in SOM-INs was prevented by inhibition of SSTRs and by depletion of SST by cysteamine treatment, suggesting a critical role of endogenous SST in LTP. LTP of SOM-IN excitatory synapses induced by SST14 was independent of NMDAR and mGluR1a, activity-dependent, and prevented by blocking GABAA receptor function. Our results indicate that endogenous SST may contribute to Hebbian LTP at excitatory synapses of SOM-INs by controlling GABAA inhibition, uncovering a novel role for SST in regulating long-term synaptic plasticity in somatostatinergic cells that may be important for hippocampus-dependent memory processes.
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Affiliation(s)
- Anne-Sophie Racine
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, QC, H3C 3J7, Canada
| | - François-Xavier Michon
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, QC, H3C 3J7, Canada
| | - Isabel Laplante
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, QC, H3C 3J7, Canada
| | - Jean-Claude Lacaille
- Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Department of Neurosciences, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, QC, H3C 3J7, Canada.
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5
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Talapka P, Kocsis Z, Marsi LD, Szarvas VE, Kisvárday ZF. Application of the Mirror Technique for Three-Dimensional Electron Microscopy of Neurochemically Identified GABA-ergic Dendrites. Front Neuroanat 2021; 15:652422. [PMID: 33958990 PMCID: PMC8093522 DOI: 10.3389/fnana.2021.652422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/25/2021] [Indexed: 11/15/2022] Open
Abstract
In the nervous system synaptic input arrives chiefly on dendrites and their type and distribution have been assumed pivotal in signal integration. We have developed an immunohistochemistry (IH)-correlated electron microscopy (EM) method – the “mirror” technique – by which synaptic input to entire dendrites of neurochemically identified interneurons (INs) can be mapped due preserving high-fidelity tissue ultrastructure. Hence, this approach allows quantitative assessment of morphometric parameters of synaptic inputs along the whole length of dendrites originating from the parent soma. The method exploits the fact that adjoining sections have truncated or cut cell bodies which appear on the common surfaces in a mirror fashion. In one of the sections the histochemical marker of the GABAergic subtype, calbindin was revealed in cell bodies whereas in the other section the remaining part of the very same cell bodies were subjected to serial section EM to trace and reconstruct the synaptology of entire dendrites. Here, we provide exemplary data on the synaptic coverage of two dendrites belonging to the same calbindin-D28K immunopositive IN and determine the spatial distribution of asymmetric and symmetric synapses, surface area and volume of the presynaptic boutons, morphometric parameters of synaptic vesicles, and area extent of the active zones.
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Affiliation(s)
- Petra Talapka
- MTA-DE Neuroscience Research Group, University of Debrecen, Debrecen, Hungary.,Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zsolt Kocsis
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Lívia Diána Marsi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Vera Etelka Szarvas
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zoltán F Kisvárday
- MTA-DE Neuroscience Research Group, University of Debrecen, Debrecen, Hungary.,Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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6
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Abstract
Neural circuit function is determined not only by anatomical connections but also by the strength and nature of the connections, that is functional or physiological connectivity. To elucidate functional connectivity, selective stimulation of presynaptic terminals of an identified neuronal population is crucial. However, in the central nervous system, intermingled input fibers make selective electrical stimulation impossible. With optogenetics, this becomes possible, and enables the comprehensive study of functional synaptic connections between an identified population of neurons and defined postsynaptic targets to determine the functional connectome. By stimulating convergent synaptic inputs impinging on individual postsynaptic neurons, low frequency and small amplitude synaptic connections can be detected. Further, the optogenetic approach enables the measurement of cotransmission and its relative strength. Recently, optogenetic methods have been more widely used to study synaptic connectivity and revealed novel synaptic connections and revised connectivity of known projections. In this chapter, I focus on functional synaptic connectivity in the striatum, the main input structure of the basal ganglia, involved in the motivated behavior, cognition, and motor control, and its disruption in a range of neuropsychiatric disorders.
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Affiliation(s)
- Nao Chuhma
- Department of Psychiatry, Columbia University, New York, NY, USA. .,Department of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA.
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7
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Léger C, Dupré N, Laquerrière A, Lecointre M, Dumanoir M, Janin F, Hauchecorne M, Fabre M, Jégou S, Frébourg T, Cleren C, Leroux P, Marcorelles P, Brasse-Lagnel C, Marret S, Marguet F, Gonzalez BJ. In utero alcohol exposure exacerbates endothelial protease activity from pial microvessels and impairs GABA interneuron positioning. Neurobiol Dis 2020; 145:105074. [PMID: 32890773 DOI: 10.1016/j.nbd.2020.105074] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 02/06/2023] Open
Abstract
In utero alcohol exposure can induce severe neurodevelopmental disabilities leading to long-term behavioral deficits. Because alcohol induces brain defects, many studies have focused on nervous cells. However, recent reports have shown that alcohol markedly affects cortical angiogenesis in both animal models and infants with fetal alcohol spectrum disorder (FASD). In addition, the vascular system is known to contribute to controlling gamma-aminobutyric acid (GABA)ergic interneuron migration in the developing neocortex. Thus, alcohol-induced vascular dysfunction may contribute to the neurodevelopmental defects in FASD. The present study aimed at investigating the effects of alcohol on endothelial activity of pial microvessels. Ex vivo experiments on cortical slices from mouse neonates revealed that in endothelial cells from pial microvessels acute alcohol exposure inhibits both glutamate-induced calcium mobilization and activities of matrix metalloproteinase-9 (MMP-9) and tissue plasminogen activator (tPA). The inhibitory effect of alcohol on glutamate-induced MMP-9 activity was abrogated in tPA-knockout and Grin1flox/VeCadcre mice suggesting that alcohol interacts through the endothelial NMDAR/tPA/MMP-9 vascular pathway. Contrasting with the effects from acute alcohol exposure, in mouse neonates exposed to alcohol in utero during the last gestational week, glutamate exacerbated both calcium mobilization and endothelial protease activities from pial microvessels. This alcohol-induced vascular dysfunction was associated with strong overexpression of the N-methyl-d-aspartate receptor subunit GluN1 and mispositioning of the Gad67-GFP interneurons that normally populate the superficial cortical layers. By comparing several human control fetuses with a fetus chronically exposed to alcohol revealed that alcohol exposure led to mispositioning of the calretinin-positive interneurons, whose density was decreased in the superficial cortical layers II-III and increased in deepest layers. This study provides the first mechanistic and functional evidence that alcohol impairs glutamate-regulated activity of pial microvessels. Endothelial dysfunction is characterized by altered metalloproteinase activity and interneuron mispositioning, which was also observed in a fetus with fetal alcohol syndrome. These data suggest that alcohol-induced endothelial dysfunction may contribute in ectopic cortical GABAergic interneurons, that has previously been described in infants with FASD.
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Affiliation(s)
- Cécile Léger
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Nicolas Dupré
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Annie Laquerrière
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Maryline Lecointre
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Marion Dumanoir
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - François Janin
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Michelle Hauchecorne
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Maëlle Fabre
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Sylvie Jégou
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Thierry Frébourg
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Carine Cleren
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Philippe Leroux
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | | | - Carole Brasse-Lagnel
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Stéphane Marret
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Florent Marguet
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Bruno J Gonzalez
- Normandie Univ, UNIROUEN, INSERM U1245 and Rouen University Hospital, Department of Neonatal Paediatrics and Intensive Care, F 76000, Normandy Centre for Genomic and Personalized Medicine, Rouen, France.
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Abstract
Glutamate and dopamine systems play distinct roles in terms of neuronal signalling, yet both have been proposed to contribute significantly to the pathophysiology of schizophrenia. In this paper we assess research that has implicated both systems in the aetiology of this disorder. We examine evidence from post-mortem, preclinical, pharmacological and in vivo neuroimaging studies. Pharmacological and preclinical studies implicate both systems, and in vivo imaging of the dopamine system has consistently identified elevated striatal dopamine synthesis and release capacity in schizophrenia. Imaging of the glutamate system and other aspects of research on the dopamine system have produced less consistent findings, potentially due to methodological limitations and the heterogeneity of the disorder. Converging evidence indicates that genetic and environmental risk factors for schizophrenia underlie disruption of glutamatergic and dopaminergic function. However, while genetic influences may directly underlie glutamatergic dysfunction, few genetic risk variants directly implicate the dopamine system, indicating that aberrant dopamine signalling is likely to be predominantly due to other factors. We discuss the neural circuits through which the two systems interact, and how their disruption may cause psychotic symptoms. We also discuss mechanisms through which existing treatments operate, and how recent research has highlighted opportunities for the development of novel pharmacological therapies. Finally, we consider outstanding questions for the field, including what remains unknown regarding the nature of glutamate and dopamine function in schizophrenia, and what needs to be achieved to make progress in developing new treatments.
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Affiliation(s)
- Robert A McCutcheon
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
- South London and Maudsley Foundation NHS Trust, Maudsley Hospital, London, UK
| | - John H Krystal
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT, USA
| | - Oliver D Howes
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
- South London and Maudsley Foundation NHS Trust, Maudsley Hospital, London, UK
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9
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Kougioumoutzakis A, Pelletier JG, Laplante I, Khlaifia A, Lacaille JC. TRPC1 mediates slow excitatory synaptic transmission in hippocampal oriens/alveus interneurons. Mol Brain 2020; 13:12. [PMID: 31996247 PMCID: PMC6988362 DOI: 10.1186/s13041-020-0558-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/21/2020] [Indexed: 12/31/2022] Open
Abstract
Hippocampal GABAergic interneurons play key roles in regulating principal cell activity and plasticity. Interneurons located in stratum oriens/alveus (O/A INs) receive excitatory inputs from CA1 pyramidal cells and express a Hebbian form of long-term potentiation (LTP) at their excitatory input synapses. This LTP requires the activation of metabotropic glutamate receptors 1a (mGluR1a) and Ca2+ entry via transient receptor potential (TRP) channels. However, the type of TRP channels involved in synaptic transmission at these synapses remains largely unknown. Using patch-clamp recordings, we show that slow excitatory postsynaptic currents (EPSCs) evoked in O/A INs are dependent on TRP channels but may be independent of phospholipase C. Using reverse transcription polymerase chain reaction (RT-PCR) we found that mRNA for TRPC 1, 3–7 was present in CA1 hippocampus. Using single-cell RT-PCR, we found expression of mRNA for TRPC 1, 4–7, but not TRPC3, in O/A INs. Using co-immunoprecipitation assays in HEK-293 cell expression system, we found that TRPC1 and TRPC4 interacted with mGluR1a. Co-immunoprecipitation in hippocampus showed that TRPC1 interacted with mGluR1a. Using immunofluorescence, we found that TRPC1 co-localized with mGluR1a in O/A IN dendrites, whereas TRPC4 localization appeared limited to O/A IN cell body. Down-regulation of TRPC1, but not TRPC4, expression in O/A INs using small interfering RNAs prevented slow EPSCs, suggesting that TRPC1 is an obligatory TRPC subunit for these EPSCs. Our findings uncover a functional role of TRPC1 in mGluR1a-mediated slow excitatory synaptic transmission onto O/A INs that could be involved in Hebbian LTP at these synapses.
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Affiliation(s)
- André Kougioumoutzakis
- Department of Neurosciences and GRSNC, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, Montreal, QC, H3C 3J7, Canada
| | - Joe Guillaume Pelletier
- Department of Neurosciences and GRSNC, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, Montreal, QC, H3C 3J7, Canada
| | - Isabel Laplante
- Department of Neurosciences and GRSNC, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, Montreal, QC, H3C 3J7, Canada
| | - Abdessattar Khlaifia
- Department of Neurosciences and GRSNC, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, Montreal, QC, H3C 3J7, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences and GRSNC, Université de Montréal, P.O. Box 6128, Station Downtown, Montreal, Montreal, QC, H3C 3J7, Canada.
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10
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Deutsch SI, Burket JA. An Evolving Therapeutic Rationale for Targeting the α 7 Nicotinic Acetylcholine Receptor in Autism Spectrum Disorder. Curr Top Behav Neurosci 2020; 45:167-208. [PMID: 32468495 DOI: 10.1007/7854_2020_136] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Abnormalities of cholinergic nuclei, cholinergic projections, and cholinergic receptors, as well as abnormalities of growth factors involved in the maturation and maintenance of cholinergic neurons, have been described in postmortem brains of persons with autism spectrum disorder (ASD). Further, microdeletions of the 15q13.3 locus that encompasses CHRNA7, the gene coding the α7 nicotinic acetylcholine receptor (α7 nAChR), are associated with a spectrum of neurodevelopmental disorders, including ASD. The heterozygous 15q13.3 microdeletion syndrome suggests that diminished or impaired transduction of the acetylcholine (ACh) signal by the α7 nAChR can be a pathogenic mechanism of ASD. The α7 nAChR has a role in regulating the firing and function of parvalbumin (PV)-expressing GABAergic projections, which synchronize the oscillatory output of assemblies of pyramidal neurons onto which they project. Synchronous oscillatory output is an electrophysiological substrate for higher executive functions, such as working memory, and functional connectivity between discrete anatomic areas of the brain. The α7 nAChR regulates PV expression and works cooperatively with the co-expressed NMDA receptor in subpopulations of GABAergic interneurons in mouse models of ASD. An evolving literature supports therapeutic exploration of selectively targeted cholinergic interventions for the treatment of ASD, especially compounds that target the α7 nAChR subtype. Importantly, development and availability of high-affinity, brain-penetrable, α7 nAChR-selective agonists, partial agonists, allosteric agonists, and positive allosteric modulators (PAMs) should facilitate "proof-of-principle/concept" clinical trials. nAChRs are pentameric allosteric proteins that function as ligand-gated ion channel receptors constructed from five constituent polypeptide subunits, all of which share a common structural motif. Importantly, in addition to α7 nAChR-gated Ca2+ conductance causing membrane depolarization, there are emerging data consistent with possible metabotropic functions of this ionotropic receptor. The ability of α7-selective type II PAMs to "destabilize" the desensitized state and promote ion channel opening may afford them therapeutic advantages over orthosteric agonists. The current chapter reviews historic and recent literature supporting selective therapeutic targeting of the α7 nAChR in persons affected with ASD.
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Affiliation(s)
- Stephen I Deutsch
- Department of Psychiatry and Behavioral Sciences, Eastern Virginia Medical School, Norfolk, VA, USA.
| | - Jessica A Burket
- Department of Molecular Biology and Chemistry, Christopher Newport University, Newport News, VA, USA
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Hernández-Vázquez F, Garduño J, Hernández-López S. GABAergic modulation of serotonergic neurons in the dorsal raphe nucleus. Rev Neurosci 2019; 30:289-303. [PMID: 30173207 DOI: 10.1515/revneuro-2018-0014] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/18/2018] [Indexed: 11/15/2022]
Abstract
The dorsal raphe nucleus (DRN), located in the brainstem, is involved in several functions such as sleep, temperature regulation, stress responses, and anxiety behaviors. This nucleus contains the largest population of serotonin expressing neurons in the brain. Serotonergic DRN neurons receive tonic γ-aminobutyric acid (GABA)inhibitory inputs from several brain areas, as well as from interneurons within the same nucleus. Serotonergic and GABAergic neurons in the DRN can be distinguished by their size, location, pharmacological responses, and electrophysiological properties. GABAergic neurons regulate the excitability of DRN serotonergic neurons and the serotonin release in different brain areas. Also, it has been shown that GABAergic neurons can synchronize the activity of serotonergic neurons across functions such as sleep or alertness. Moreover, dysregulation of GABA signaling in the DRN has been linked to psychiatric disorders such as anxiety and depression. This review focuses on GABAergic transmission in the DRN. The interaction between GABAergic and serotonergic neurons is discussed considering some physiological implications. Also, the main electrophysiological and morphological characteristics of serotonergic and GABAergic neurons are described.
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Affiliation(s)
- Fabiola Hernández-Vázquez
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Julieta Garduño
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, PO Box 70250, Ciudad de México 04510, México
| | - Salvador Hernández-López
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, PO Box 70250, Ciudad de México 04510, México, e-mail:
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Krajcovic B, Fajnerova I, Horacek J, Kelemen E, Kubik S, Svoboda J, Stuchlik A. Neural and neuronal discoordination in schizophrenia: From ensembles through networks to symptoms. Acta Physiol (Oxf) 2019; 226:e13282. [PMID: 31002202 DOI: 10.1111/apha.13282] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 12/22/2022]
Abstract
Despite the substantial knowledge accumulated by past research, the exact mechanisms of the pathogenesis of schizophrenia and causal treatments still remain unclear. Deficits of cognition and information processing in schizophrenia are today often viewed as the primary and core symptoms of this devastating disorder. These deficits likely result from disruptions in the coordination of neuronal and neural activity. The aim of this review is to bring together convergent evidence of discoordinated brain circuits in schizophrenia at multiple levels of resolution, ranging from principal cells and interneurons, neuronal ensembles and local circuits, to large-scale brain networks. We show how these aberrations could underlie deficits in cognitive control and other higher order cognitive-behavioural functions. Converging evidence from both animal models and patients with schizophrenia is presented in an effort to gain insight into common features of deficits in the brain information processing in this disorder, marked by disruption of several neurotransmitter and signalling systems and severe behavioural outcomes.
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Affiliation(s)
- Branislav Krajcovic
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Third Faculty of Medicine Charles University Prague Czech Republic
| | - Iveta Fajnerova
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Jiri Horacek
- Third Faculty of Medicine Charles University Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Eduard Kelemen
- Research Programme 1 - Experimental Neurobiology National Institute of Mental Health Klecany Czech Republic
| | - Stepan Kubik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Jan Svoboda
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Ales Stuchlik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
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Holley SM, Galvan L, Kamdjou T, Dong A, Levine MS, Cepeda C. Major Contribution of Somatostatin-Expressing Interneurons and Cannabinoid Receptors to Increased GABA Synaptic Activity in the Striatum of Huntington's Disease Mice. Front Synaptic Neurosci 2019; 11:14. [PMID: 31139071 PMCID: PMC6527892 DOI: 10.3389/fnsyn.2019.00014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/23/2019] [Indexed: 01/01/2023] Open
Abstract
Huntington’s disease (HD) is a heritable neurological disorder that affects cognitive and motor performance in patients carrying the mutated huntingtin (HTT) gene. In mouse models of HD, previous reports showed a significant increase in spontaneous GABAA receptor-mediated synaptic activity in striatal spiny projection neurons (SPNs). In this study, using optogenetics and slice electrophysiology, we examined the contribution of γ-aminobutyric acid (GABA)-ergic parvalbumin (PV)- and somatostatin (SOM)-expressing interneurons to the increase in GABA neurotransmission using the Q175 (heterozygote) mouse model of HD. Patch clamp recordings in voltage-clamp mode were performed on SPNs from brain slices of presymptomatic (2 months) and symptomatic (8 and 12 months) Q175 mice and wildtype (WT) littermates. While inhibitory postsynaptic currents (IPSCs) evoked in SPNs following optical activation of PV- and SOM-expressing interneurons differed in amplitude, no genotype-dependent differences were observed at all ages from both interneuron types; however, responses evoked by either type were found to have faster kinetics in symptomatic mice. Since SOM-expressing interneurons are constitutively active in striatal brain slices, we then examined the effects of acutely silencing these neurons in symptomatic mice with enhanced Natronomonas pharaonis halorhodopsin (eNpHR). Optically silencing SOM-expressing interneurons resulted in a greater decrease in the frequency of spontaneous IPSCs (sIPSCs) in a subset of SPNs from Q175 mice compared to WTs, suggesting that SOM-expressing interneurons are the main contributors to the overall increased GABA synaptic activity in HD SPNs. Additionally, the effects of activating GABAB and cannabinoid (CB1) receptors were investigated to determine whether these receptors were involved in modulating interneuron-specific GABA synaptic transmission and if this modulation differed in HD mice. When selectively activating PV- and SOM-expressing interneurons in the presence of the CB1 receptor agonist WIN-55,212, the magnitudes of the evoked IPSCs in SPNs decreased for both interneuron types although this change was less prominent in symptomatic Q175 SPNs during SOM-expressing interneuron activation. Overall, these findings show that dysfunction of SOM-expressing interneurons contributes to the increased GABA synaptic activity found in HD mouse models and that dysregulation of the endocannabinoid system may contribute to this effect.
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Affiliation(s)
- Sandra M Holley
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Laurie Galvan
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Talia Kamdjou
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Ashley Dong
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
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Holley SM, Galvan L, Kamdjou T, Cepeda C, Levine MS. Striatal GABAergic interneuron dysfunction in the Q175 mouse model of Huntington's disease. Eur J Neurosci 2018; 49:79-93. [PMID: 30472747 DOI: 10.1111/ejn.14283] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/01/2018] [Accepted: 11/13/2018] [Indexed: 01/01/2023]
Abstract
The pathological hallmark of Huntington's disease (HD) is the massive loss of striatal and cortical neurons. Until recently, it was believed that striatal interneurons were spared from degeneration. This view has changed after the demonstration that parvalbumin (PV)-expressing interneurons also are vulnerable in humans. Here we compared morphological and functional changes of striatal fast-spiking interneurons (FSIs) and low-threshold spiking (LTS) interneurons in the Q175 mouse model of HD at presymptomatic (2 months) and symptomatic (12 months) stages of the disease. Electrophysiological intrinsic and synaptic properties of FSIs were significantly altered in symptomatic mice compared to wild-type (WT) littermates. Overall, FSIs became more excitable with disease progression. Sholl analysis also revealed a significant loss of dendritic complexity and excitatory synaptic inputs. The basic membrane and synaptic properties of LTS interneurons were similar in Q175 and WT mice regardless of disease stage. The resilience of LTS interneurons could be related to their sparsity of excitatory synaptic inputs compared with FSIs. However, in symptomatic mice, a subpopulation of LTS interneurons displayed an increase in action potential firing within oscillating bursts. Thus, we conclude that while both FSI and LTS interneurons demonstrate increases in excitability, the HD mutation differentially affects their membrane and synaptic properties as well as their ability to respond to compensatory challenges presented during the late stage of the disease. Alterations in GABAergic interneuron intrinsic activity and responsiveness to incoming signals may significantly affect SPN output thus contributing to abnormal motor movements in patients afflicted with HD.
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Affiliation(s)
- Sandra M Holley
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, UCLA, Los Angeles, California
| | - Laurie Galvan
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, UCLA, Los Angeles, California
| | - Talia Kamdjou
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, UCLA, Los Angeles, California
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, UCLA, Los Angeles, California
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, UCLA, Los Angeles, California
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15
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MacKay MAB, Paylor JW, Wong JTF, Winship IR, Baker GB, Dursun SM. Multidimensional Connectomics and Treatment-Resistant Schizophrenia: Linking Phenotypic Circuits to Targeted Therapeutics. Front Psychiatry 2018; 9:537. [PMID: 30425662 PMCID: PMC6218602 DOI: 10.3389/fpsyt.2018.00537] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/10/2018] [Indexed: 01/08/2023] Open
Abstract
Schizophrenia is a very complex syndrome that involves widespread brain multi-dysconnectivity. Neural circuits within specific brain regions and their links to corresponding regions are abnormal in the illness. Theoretical models of dysconnectivity and the investigation of connectomics and brain network organization have been examined in schizophrenia since the early nineteenth century. In more recent years, advancements have been achieved with the development of neuroimaging tools that have provided further clues to the structural and functional organization of the brain and global neural networks in the illness. Neural circuitry that extends across prefrontal, temporal and parietal areas of the cortex as well as limbic and other subcortical brain regions is disrupted in schizophrenia. As a result, many patients have a poor response to antipsychotic treatment and treatment failure is common. Treatment resistance that is specific to positive, negative, and cognitive domains of the illness may be related to distinct circuit phenotypes unique to treatment-refractory disease. Currently, there are no customized neural circuit-specific and targeted therapies that address this neural dysconnectivity. Investigation of targeted therapeutics that addresses particular areas of substantial regional dysconnectivity is an intriguing approach to precision medicine in schizophrenia. This review examines current findings of system and circuit-level brain dysconnectivity in treatment-resistant schizophrenia based on neuroimaging studies. Within a connectome context, on-off circuit connectivity synonymous with excitatory and inhibitory neuronal pathways is discussed. Mechanistic cellular, neurochemical and molecular studies are included with specific emphasis given to cell pathology and synaptic communication in glutamatergic and GABAergic systems. In this review we attempt to deconstruct how augmenting treatments may be applied within a circuit context to improve circuit integration and treatment response. Clinical studies that have used a variety of glutamate receptor and GABA interneuron modulators, nitric oxide-based therapies and a variety of other strategies as augmenting treatments with antipsychotic drugs are included. This review supports the idea that the methodical mapping of system-level networks to both on (excitatory) and off (inhibitory) cellular circuits specific to treatment-resistant disease may be a logical and productive approach in directing future research toward the advancement of targeted pharmacotherapeutics in schizophrenia.
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Affiliation(s)
- Mary-Anne B MacKay
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - John W Paylor
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - James T F Wong
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Ian R Winship
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Glen B Baker
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Serdar M Dursun
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
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Wang S, Zhao Y, Gao J, Guo Y, Wang X, Huo J, Wei P, Cao J. In Vivo Effect of a 5-HT 7 Receptor Agonist on 5-HT Neurons and GABA Interneurons in the Dorsal Raphe Nuclei of Sham and PD Rats. Am J Alzheimers Dis Other Demen 2017; 32:73-81. [PMID: 28084087 PMCID: PMC10852805 DOI: 10.1177/1533317516685425] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2024]
Abstract
The 5-hydroxytryptamine (5-HT; serotonin) neurotransmission is severely affected by the degeneration of nigrostriatal dopaminergic neurons. Here, we report the effects of the systemic administration of the 5-HT7 receptor agonist AS-19. In sham rats, the mean response of the 5-HT neurons in the dorsal raphe nucleus (DRN) to systemic AS-19 was excitatory and the mean response of the γ-aminobutyric acid (GABA) interneurons was inhibitory. In Parkinson disease (PD) rats, the same dose did not affect the 5-HT neurons and only high doses (640 μg/kg intravenous) were able to the increase GABA interneuron activity. These results indicate that DRN 5-HT neurons and GABA interneurons are regulated by the activation of 5-HT7 receptors and that the degeneration of the nigrostriatal pathway leads to decreased responses of these neurons to AS-19, which in turn suggests that the 5-HT7 receptors on 5-HT neurons and GABA interneurons in PD rats are dysfunctional and downregulated.
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Affiliation(s)
- Shuang Wang
- Department of Pathophysiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Yan Zhao
- Department of Pathophysiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Jie Gao
- Department of Pathophysiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Yufang Guo
- Department of Pathophysiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Xiang Wang
- Department of Pathophysiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Jian Huo
- Department of Pathophysiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Ping Wei
- Department of Immunology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Jian Cao
- Department of Physiology, Institute of Basic Medical Science, Xi’an Medical University, Xi’an, China
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Roux C, Aligny C, Lesueur C, Girault V, Brunel V, Ramdani Y, Genty D, Driouich A, Laquerrière A, Marret S, Brasse-Lagnel C, Gonzalez BJ, Bekri S. NMDA receptor blockade in the developing cortex induces autophagy-mediated death of immature cortical GABAergic interneurons: An ex vivo and in vivo study in Gad67-GFP mice. Exp Neurol 2015; 267:177-93. [PMID: 25795167 DOI: 10.1016/j.expneurol.2015.02.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/14/2015] [Accepted: 02/05/2015] [Indexed: 01/16/2023]
Abstract
In neonates, excitotoxicity is a major process involved in hypoxic-ischemic brain lesions, and several research groups have suggested the use of NMDA antagonists for neuroprotection. However, despite their clinical interest, there is more and more evidence suggesting that, in the immature brain, these molecules exert deleterious actions on migrating GABAergic interneurons by suppressing glutamatergic trophic inputs. Consequently, preventing the side effects of NMDA antagonists would be therapeutically useful. Because macroautophagy is involved in the adaptive response to trophic deprivation, the aim of the present study was to investigate the impact of autophagy modulators on the MK801-induced death of immature GABAergic interneurons and to characterize the crosstalk between autophagic and apoptotic mechanisms in this cell type. Ex vivo, using cortical slices from NMRI and Gad67-GFP mice, we show that blockade of the NMDA receptor results in an accumulation of autophagosomes due to the disruption of the autophagic flux. This effect precedes the activation of the mitochondrial apoptotic pathway, and the degeneration of immature GABAergic neurons present in developing cortical layers II-IV and is prevented by 3-MA, an autophagy inhibitor. In contrast, modulators of autophagy (3-MA, rapamycin) do not interfere with the anti-excitotoxic and neuroprotective effect of MK801 observed in deep layers V and VI. In vivo, 3-MA blocks the rapid increase in caspase-3 cleavage induced by the blockade of NMDA receptors and prevents the resulting long-term decrease in Gad67-GFP neurons in layers II-IV. Together, these data suggest that, in the developing cortex, the suppression of glutamatergic inputs through NMDA receptor inhibition results in the impairment of the autophagic flux and the subsequent switch to apoptotic death of immature GABAergic interneurons. The concomitant inhibition of autophagy prevents this pro-apoptotic action of the NMDA blocker and favors the long-term rescue of GABAergic interneurons without interfering with its neuroprotective actions. The use of autophagy modulators in the developing brain would create new opportunities to prevent the side effects of NMDA antagonists used for neuroprotection or anesthesia.
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Affiliation(s)
- Christian Roux
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Caroline Aligny
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Céline Lesueur
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Virginie Girault
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Valery Brunel
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Yasmina Ramdani
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Damien Genty
- Department of Pathology, Rouen University Hospital, Rouen, France
| | - Azeddine Driouich
- Research Platform of Cell Imagery (PRIMACEN), France; Laboratory of Glycobiology and Plant Extracellular Matrix (GLYCOMEV) EA 4358, France
| | - Annie Laquerrière
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Pathology, Rouen University Hospital, Rouen, France
| | - Stéphane Marret
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Neonatal Paediatrics and Intensive Care, Rouen University Hospital, Rouen, France
| | - Carole Brasse-Lagnel
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Bruno J Gonzalez
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France.
| | - Soumeya Bekri
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
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Viguier F, Michot B, Hamon M, Bourgoin S. Multiple roles of serotonin in pain control mechanisms--implications of 5-HT₇ and other 5-HT receptor types. Eur J Pharmacol 2013; 716:8-16. [PMID: 23500207 DOI: 10.1016/j.ejphar.2013.01.074] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/30/2012] [Accepted: 01/29/2013] [Indexed: 11/25/2022]
Abstract
Among monoamine neurotransmitters, serotonin (5-HT) is known to play complex modulatory roles in pain signaling mechanisms since the first reports, about forty years ago, on its essentially pro-nociceptive effects at the periphery and anti-nociceptive effects when injected directly at the spinal cord level. The discovery of multiple 5-HT receptor subtypes allowed possible explanations to this dual action at the periphery versus the central nervous system (CNS) since both excitatory and inhibitory effects can be exerted through 5-HT activation of different 5-HT receptors. However, it also appeared that activation of the same receptor subtype at CNS level might induce variable effects depending on the physiological or pathophysiological status of the animal administered with agonists. In particular, the marked neuroplastic changes induced by nerve lesion, which account for sensitization of pain signaling mechanisms, can contribute to dramatic changes in the effects of a given 5-HT receptor agonist in neuropathic rats versus intact healthy rats. This has notably been observed with 5-HT₇ receptor agonists which exert a pronociceptive action in healthy rats but alleviate hyperalgesia consecutive to nerve lesion in neuropathic animals. Analysis of cellular mechanisms underlying such dual 5-HT actions mediated by a single receptor subtype indicates that the neuronal phenotype which expresses this receptor also plays a key role in determining which modulatory action 5-HT would finally exert on pain signaling mechanisms.
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Affiliation(s)
- Florent Viguier
- INSERM U894, CPN, Neuropsychopharmacology, Faculty of Medicine Pierre & Marie Curie, UPMC, Site Pitié-Salpêtrière, 75013 Paris, France; University Pierre et Marie Curie (UPMC), Neuropsychopharmacology, Faculty of Medicine Pierre & Marie Curie, UPMC, Site Pitié-Salpêtrière, 75013 Paris, France.
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