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Arora I, Mal P, Arora P, Paul A, Kumar M. GABAergic implications in anxiety and related disorders. Biochem Biophys Res Commun 2024; 724:150218. [PMID: 38865810 DOI: 10.1016/j.bbrc.2024.150218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/05/2024] [Accepted: 06/02/2024] [Indexed: 06/14/2024]
Abstract
Evidence indicates that anxiety disorders arise from an imbalance in the functioning of brain circuits that govern the modulation of emotional responses to possibly threatening stimuli. The circuits under consideration in this context include the amygdala's bottom-up activity, which signifies the existence of stimuli that may be seen as dangerous. Moreover, these circuits encompass top-down regulatory processes that originate in the prefrontal cortex, facilitating the communication of the emotional significance associated with the inputs. Diverse databases (e.g., Pubmed, ScienceDirect, Web of Science, Google Scholar) were searched for literature using a combination of different terms e.g., "anxiety", "stress", "neuroanatomy", and "neural circuits", etc. A decrease in GABAergic activity is present in both anxiety disorders and severe depression. Research on cerebral functional imaging in depressive individuals has shown reduced levels of GABA within the cortical regions. Additionally, animal studies demonstrated that a reduction in the expression of GABAA/B receptors results in a behavioral pattern resembling anxiety. The amygdala consists of inhibitory networks composed of GABAergic interneurons, responsible for modulating anxiety responses in both normal and pathological conditions. The GABAA receptor has allosteric sites (e.g., α/γ, γ/β, and α/β) which enable regulation of neuronal inhibition in the amygdala. These sites serve as molecular targets for anxiolytic medications such as benzodiazepine and barbiturates. Alterations in the levels of naturally occurring regulators of these allosteric sites, along with alterations to the composition of the GABAA receptor subunits, could potentially act as mechanisms via which the extent of neuronal inhibition is diminished in pathological anxiety disorders.
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Affiliation(s)
- Indu Arora
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Pankaj Mal
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Poonam Arora
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Anushka Paul
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Manish Kumar
- Chitkara College of Pharmacy, Chitkara University, Punjab, India.
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2
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Granados-Fuentes D, Lambert P, Simon T, Mennerick S, Herzog ED. GABA A receptor subunit composition regulates circadian rhythms in rest-wake and synchrony among cells in the suprachiasmatic nucleus. Proc Natl Acad Sci U S A 2024; 121:e2400339121. [PMID: 39047036 DOI: 10.1073/pnas.2400339121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 06/24/2024] [Indexed: 07/27/2024] Open
Abstract
The mammalian circadian clock located in the suprachiasmatic nucleus (SCN) produces robust daily rhythms including rest-wake. SCN neurons synthesize and respond to γ-aminobutyric acid (GABA), but its role remains unresolved. We tested the hypothesis that γ2- and δ-subunits of the GABAA receptor in the SCN differ in their regulation of synchrony among circadian cells. We used two approaches: 1) shRNA to knock-down (KD) the expression of either γ2 or δ subunits in the SCN or 2) knock-in mice harboring a point mutation in the M2 domains of the endogenous GABAA γ2 or δ subunits. KD of either γ2 or δ subunits in the SCN increased daytime running and reduced nocturnal running by reducing their circadian amplitude by a third. Similarly, δ subunit knock-in mice showed decreased circadian amplitude, increased duration of daily activity, and decreased total daily activity. Reduction, or mutation of either γ2 or δ subunits halved the synchrony among, and amplitude of, circadian SCN cells as measured by firing rate or expression of the PERIOD2 protein, in vitro. Surprisingly, overexpression of the γ2 subunit rescued these phenotypes following KD or mutation of the δ subunit, and overexpression of the δ subunit rescued deficiencies due to γ2 subunit KD or mutation. We conclude that γ2 and δ GABAA receptor subunits play similar roles in maintaining circadian synchrony in the SCN and amplitude of daily rest-wake rhythms, but that modulation of their relative densities can change the duration and amplitude of daily activities.
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Affiliation(s)
| | - Peter Lambert
- Department of Psychiatry, Washington University in St. Louis, MO 63130-4899
| | - Tatiana Simon
- Department of Biology, Washington University in St. Louis, MO 63130-4899
| | - Steven Mennerick
- Department of Psychiatry, Washington University in St. Louis, MO 63130-4899
| | - Erik D Herzog
- Department of Biology, Washington University in St. Louis, MO 63130-4899
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3
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Mortensen JS, Mikkelsen ANL, Wellendorph P. Ways of modulating GABA transporters to treat neurological disease. Expert Opin Ther Targets 2024; 28:529-543. [PMID: 39068514 DOI: 10.1080/14728222.2024.2383611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 07/19/2024] [Indexed: 07/30/2024]
Abstract
INTRODUCTION The main inhibitory neurotransmitter in the central nervous system (CNS), γ-aminobutyric acid (GABA), is involved in a multitude of neurological and psychiatric disorders characterized by an imbalance in excitatory and inhibitory signaling. Regulation of extracellular levels of GABA is maintained by the four GABA transporters (GATs; GAT1, GAT2, GAT3, and BGT1), Na+/Cl--coupled transporters of the solute carrier 6 (SLC6) family. Despite mounting evidence for the involvement of the non-GAT1 GABA transporters in diseases, only GAT1 has successfully been translated into clinical practice via the drug tiagabine. AREAS COVERED In this review, all four GATs will be described in terms of their involvement in disease, and the most recent data on structure, function, expression, and localization discussed in relation to their potential role as drug targets. This includes an overview of various ways to modulate the GATs in relation to treatment of diseases caused by imbalances in the GABAergic system. EXPERT OPINION The recent publication of various GAT1 structures is an important milestone for future development of compounds targeting the GATs. Such information can provide much needed insight into mechanistic aspects of all GAT subtypes and be utilized to design improved ligands for this highly interesting drug target class.
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Affiliation(s)
- Jonas S Mortensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Amalie N L Mikkelsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Zhang W, Liu T, Li J, Singh J, Chan A, Islam A, Petrache A, Peng Y, Harvey K, Ali AB. Decreased extrasynaptic δ-GABA A receptors in PNN-associated parvalbumin interneurons correlates with anxiety in APP and tau mouse models of Alzheimer's disease. Br J Pharmacol 2024. [PMID: 38886118 DOI: 10.1111/bph.16441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is associated with gradual memory loss and anxiety which affects ~75% of AD patients. This study investigated whether AD-associated anxiety correlated with modulation of extrasynaptic δ-subunit-containing GABAA receptors (δ-GABAARs) in experimental mouse models of AD. EXPERIMENTAL APPROACH We combined behavioural experimental paradigms to measure cognition performance, and anxiety with neuroanatomy and molecular biology, using familial knock-in (KI) mouse models of AD that harbour β-amyloid (Aβ) precursor protein App (AppNL-F) with or without humanized microtubule-associated protein tau (MAPT), age-matched to wild-type control mice at three different age windows. RESULTS AppNL-F KI and AppNL-F/MAPT AD models showed a similar magnitude of cognitive decline and elevated magnitude of anxiety correlated with neuroinflammatory hallmarks, including triggering receptor expressed on myeloid cells 2 (TREM2), reactive astrocytes and activated microglia consistent with accumulation of Aβ, tau and down-regulation of Wnt/β-catenin signalling compared to aged-matched WT controls. In both the CA1 region of the hippocampus and dentate gyrus, there was an age-dependent decline in the expression of δ-GABAARs selectively expressed in parvalbumin (PV)-expressing interneurons, encapsulated by perineuronal nets (PNNs) in the AD mouse models compared to WT mice. In vivo positive allosteric modulation of the δ-GABAARs, using a δ-selective-compound DS2, decreased the level of anxiety in the AD mouse models, which was correlated with reduced hallmarks of neuroinflammation, and 'normalisation' of the expression of δ-GABAARs. CONCLUSIONS Our data show that the δ-GABAARs could potentially be targeted for alleviating symptoms of anxiety, which would greatly improve the quality of life of AD individuals.
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Issahaku AR, Wilhelm A, Schutte-Smith M, Erasmus E, Visser H. Elucidating the binding mechanisms of GABA and Muscimol as an avenue to discover novel GABA-mimetic small molecules. J Biomol Struct Dyn 2024:1-16. [PMID: 38520326 DOI: 10.1080/07391102.2024.2331088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/10/2024] [Indexed: 03/25/2024]
Abstract
Gamma-aminobutyric acid (GABA) signaling is the principal inhibitory pathway in the central nervous system. It is critical in neuronal cell proliferation and fate determination. Any aberration in GABA inhibition results in psychiatric and neurological diseases. Thus, modulating GABAergic neurotransmission has become the basis of drug therapy for psychiatric and several neurological diseases. Though GABA and muscimol are classical inhibitors of GABA receptors, the search for novel inhibitors continues unabated. In this study, the binding mechanism of GABA and muscimol was elucidated and applied in the search for small molecule GABAergic inhibitors using comprehensive computational techniques. It was revealed that a high-affinity binding of GABA and muscimol was mediated by a water molecule involving α1Thr129 and then stabilized by strong interactions including salt bridges with β2Glu155 and α1Arg66 amidst hydrogen bonds, π-π stacking, and π -cation interactions with other residues. The binding of GABA and muscimol was also characterized by stability and deeper penetration into the hydrophobic core of the protein which resulted in conformational changes of the binding pocket and domain, by inducing correlated motions of the residues. Thermodynamics analysis showed GABA and muscimol exhibited total binding free energies of -19.85 ± 8.83 Kcal/mol and -26.55 ± 3.42 Kcal/mol, respectively. A pharmacophore model search, based on the energy contributions of implicating binding residues, resulted in the identification of ZINC68604167, ZINC19735138, ZINC04202466, ZINC00901626, and ZINC01532854 as potential GABA-mimetic compounds from metabolites and natural products libraries. This study has elucidated the binding mechanisms of GABA and muscimol and successfully applied in the identification of GABA-mimetic compounds.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Anke Wilhelm
- Department of Chemistry, University of the Free State, Bloemfontein, South Africa
| | | | - Elizabeth Erasmus
- Department of Chemistry, University of the Free State, Bloemfontein, South Africa
| | - Hendrik Visser
- Department of Chemistry, University of the Free State, Bloemfontein, South Africa
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Vilnite FM, Marnauza M. Repetition and practice. Developing mental training with young violinists: a collaboration. Front Psychol 2024; 15:1327763. [PMID: 38449761 PMCID: PMC10915241 DOI: 10.3389/fpsyg.2024.1327763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/08/2024] [Indexed: 03/08/2024] Open
Abstract
Mental training has been used successfully by professional musicians and athletes, yet rarely applied in pedagogical processes. As research in neuroscience can now explain how it connects to the processes of learning, its application and adaptation in pedagogy can now be explored. The aim of this mixed methods study was to investigate concepts of repetition and practice with mental training, and discuss adaptations for young violinists, to include attention, awareness, and creative musicality. Three exercises were developed with nine students (average age 8). The first involved creation of imagery, followed by physical practice; the second alternated mental imagery with physical practice; the third involved concurrent use of physical practice and mental imagery. Results of the first exercise indicate heightened awareness of technical skill; self-discovery of bow control, speed and distribution, tone production improvements and an ability to sustain longer notes post-mental training (Z = -2.666, p = 0.008 and Z = -2.670, p = 0.008). Observations from the second and third exercises include student experimentation with concepts of musical interpretation, an eagerness to repeat repertoire (≥ 5 times) and increased self-awareness of technical and musical accomplishments. The research suggests that mental training can be adapted for younger learners, that it encourages collaboration in the pedagogical process, and develops student self-awareness of the cognitive and physical processes of violin playing.
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Affiliation(s)
- Fiona Mary Vilnite
- Faculty of Education, Psychology and Art, University of Latvia, Riga, Latvia
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Liu W, Huang Z, Zhang Y, Zhang S, Cui Z, Liu W, Li L, Xia J, Zou Y, Qi Z. ASMT determines gut microbiota and increases neurobehavioral adaptability to exercise in female mice. Commun Biol 2023; 6:1126. [PMID: 37935873 PMCID: PMC10630421 DOI: 10.1038/s42003-023-05520-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 10/27/2023] [Indexed: 11/09/2023] Open
Abstract
N-acetylserotonin O-methyltransferase (ASMT) is responsible for melatonin biosynthesis. The Asmt gene is located on the X chromosome, and its genetic polymorphism is associated with depression in humans. However, the underlying mechanism remains unclear. Here, we use CRISPR/Cas9 to delete 20 bp of exon 2 of Asmt, and construct C57BL/6J mouse strain with Asmt frameshift mutation (Asmtft/ft). We show that female Asmtft/ft mice exhibit anxiety- and depression-like behaviors, accompanied by an obvious structural remodeling of gut microbiota. These behavioral abnormalities are not observed in male. Moreover, female Asmtft/ft mice show a lower neurobehavioral adaptability to exercise, while wild-type shows a "higher resilience". Cross-sectional and longitudinal analysis indicates that the structure of gut microbiota in Asmtft/ft mice is less affected by exercise. These results suggests that Asmt maintains the plasticity of gut microbiota in female, thereby enhancing the neurobehavioral adaptability to exercise.
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Affiliation(s)
- Weina Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China.
| | - Zhuochun Huang
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Ye Zhang
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Sen Zhang
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Zhiming Cui
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Wenbin Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Lingxia Li
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Jie Xia
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Yong Zou
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Zhengtang Qi
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.
- College of Physical Education and Health, East China Normal University, Shanghai, 200241, China.
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8
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Koh W, Kwak H, Cheong E, Lee CJ. GABA tone regulation and its cognitive functions in the brain. Nat Rev Neurosci 2023; 24:523-539. [PMID: 37495761 DOI: 10.1038/s41583-023-00724-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 07/28/2023]
Abstract
γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter released at GABAergic synapses, mediating fast-acting phasic inhibition. Emerging lines of evidence unequivocally indicate that a small amount of extracellular GABA - GABA tone - exists in the brain and induces a tonic GABA current that controls neuronal activity on a slow timescale relative to that of phasic inhibition. Surprisingly, studies indicate that glial cells that synthesize GABA, such as astrocytes, release GABA through non-vesicular mechanisms, such as channel-mediated release, and thereby act as the source of GABA tone in the brain. In this Review, we first provide an overview of major advances in our understanding of the cell-specific molecular and cellular mechanisms of GABA synthesis, release and clearance that regulate GABA tone in various brain regions. We next examine the diverse ways in which the tonic GABA current regulates synaptic transmission and synaptic plasticity through extrasynaptic GABAA-receptor-mediated mechanisms. Last, we discuss the physiological mechanisms through which tonic inhibition modulates cognitive function on a slow timescale. In this Review, we emphasize that the cognitive functions of tonic GABA current extend beyond mere inhibition, laying a foundation for future research on the physiological and pathophysiological roles of GABA tone regulation in normal and abnormal psychiatric conditions.
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Affiliation(s)
- Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea
| | - Hankyul Kwak
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea.
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Fries GR, Saldana VA, Finnstein J, Rein T. Molecular pathways of major depressive disorder converge on the synapse. Mol Psychiatry 2023; 28:284-297. [PMID: 36203007 PMCID: PMC9540059 DOI: 10.1038/s41380-022-01806-1] [Citation(s) in RCA: 110] [Impact Index Per Article: 110.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 09/07/2022] [Accepted: 09/14/2022] [Indexed: 01/07/2023]
Abstract
Major depressive disorder (MDD) is a psychiatric disease of still poorly understood molecular etiology. Extensive studies at different molecular levels point to a high complexity of numerous interrelated pathways as the underpinnings of depression. Major systems under consideration include monoamines, stress, neurotrophins and neurogenesis, excitatory and inhibitory neurotransmission, mitochondrial dysfunction, (epi)genetics, inflammation, the opioid system, myelination, and the gut-brain axis, among others. This review aims at illustrating how these multiple signaling pathways and systems may interact to provide a more comprehensive view of MDD's neurobiology. In particular, considering the pattern of synaptic activity as the closest physical representation of mood, emotion, and conscience we can conceptualize, each pathway or molecular system will be scrutinized for links to synaptic neurotransmission. Models of the neurobiology of MDD will be discussed as well as future actions to improve the understanding of the disease and treatment options.
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Affiliation(s)
- Gabriel R. Fries
- grid.267308.80000 0000 9206 2401Translational Psychiatry Program, Faillace Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, 1941 East Rd, Houston, TX 77054 USA ,grid.240145.60000 0001 2291 4776Neuroscience Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, 6767 Bertner Ave, Houston, TX 77030 USA
| | - Valeria A. Saldana
- grid.262285.90000 0000 8800 2297Frank H. Netter MD School of Medicine at Quinnipiac University, 370 Bassett Road, North Haven, CT 06473 USA
| | - Johannes Finnstein
- grid.419548.50000 0000 9497 5095Department of Translational Research in Psychiatry, Project Group Molecular Pathways of Depression, Max Planck Institute of Psychiatry, Kraepelinstr. 10, 80804 Munich, Germany
| | - Theo Rein
- Department of Translational Research in Psychiatry, Project Group Molecular Pathways of Depression, Max Planck Institute of Psychiatry, Kraepelinstr. 10, 80804, Munich, Germany.
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10
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Schoenberg HL, Bremer GP, Carasi-Schwartz F, VonDoepp S, Arntsen C, Anacker AMJ, Toufexis DJ. Cyclic estrogen and progesterone during instrumental acquisition contributes to habit formation in female rats. Horm Behav 2022; 142:105172. [PMID: 35405411 DOI: 10.1016/j.yhbeh.2022.105172] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 03/02/2022] [Accepted: 04/02/2022] [Indexed: 11/22/2022]
Abstract
Habit formation is thought to involve two parallel processes that are mediated by distinct neural substates: one that suppresses goal-directed behavior, and one that facilitates stimulus-response (S-R) learning, which underscores habitual behavior. In previous studies we showed that habitual responding emerges early during instrumental training in gonadally-intact female, compared to male, rats. The present study aimed to determine the role of ovarian hormones during instrumental acquisition in the transition from goal-directed to habitual behavior in female rats. Ovariectomized (OVX) female rats were given subcutaneous silastic capsules that released low levels of 17-β estradiol (E2) to maintain estrogen receptor availability. Rats were assigned to one of three hormone treatment conditions: no additional hormone replacement (Control group), replacement with high E2 (High E2 group), or replacement with high E2 followed by progesterone (High E2 + P4 group). Hormone replacement occurred twice during acquisition to mimic natural hormone fluctuations. At test, the Control and High E2 groups demonstrated responding that was sensitive to devaluation by lithium chloride-induced illness, indicating goal-directed behavior. In contrast, the High E2 + P4 group exhibited a pattern of devaluation-insensitive, habitual responding, that suggested the suppression of goal-directed processes. In a follow-up experiment, similar procedures were conducted, however during acquisition, OVX rats were given cyclic high E2 plus medroxy-progesterone (MPA), a form of progesterone that does not metabolize to neuroactive metabolites. In this group, goal-directed behavior was observed. These data indicate that habit formation is not facilitated in low estrogen states, nor in the presence of cyclic high E2. However, cyclic high E2, together with progesterone during acquisition, appears to facilitate the early emergence of habitual responding. Furthermore, these data suggest that a neuroactive progesterone metabolite, like allopregnanolone, in combination with high cyclic E2, supports this phenomenon.
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Affiliation(s)
- Hannah L Schoenberg
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America.
| | - Gillian P Bremer
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America
| | - Francesca Carasi-Schwartz
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America
| | - Sarah VonDoepp
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America
| | - Christian Arntsen
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America
| | - Allison M J Anacker
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America
| | - Donna J Toufexis
- Department of Psychological Science, University of Vermont, Burlington, VT 05401, United States of America.
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11
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Belelli D, Phillips GD, Atack JR, Lambert JJ. Relating neurosteroid modulation of inhibitory neurotransmission to behaviour. J Neuroendocrinol 2022; 34:e13045. [PMID: 34644812 DOI: 10.1111/jne.13045] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/24/2021] [Accepted: 09/15/2021] [Indexed: 12/11/2022]
Abstract
Studies in the 1980s revealed endogenous metabolites of progesterone and deoxycorticosterone to be potent, efficacious, positive allosteric modulators (PAMs) of the GABAA receptor (GABAA R). The discovery that such steroids are locally synthesised in the central nervous system (CNS) promoted the thesis that neural inhibition in the CNS may be "fine-tuned" by these neurosteroids to influence behaviour. In preclinical studies, these neurosteroids exhibited anxiolytic, anticonvulsant, analgesic and sedative properties and, at relatively high doses, induced a state of general anaesthesia, a profile consistent with their interaction with GABAA Rs. However, realising the therapeutic potential of either endogenous neurosteroids or synthetic "neuroactive" steroids has proven challenging. Recent approval by the Food and Drug Administration of the use of allopregnanolone (brexanolone) to treat postpartum depression has rekindled enthusiasm for exploring their potential as new medicines. Although neurosteroids are selective for GABAA Rs, they exhibit little or no selectivity across the many GABAA R subtypes. Nevertheless, a relatively minor population of receptors incorporating the δ-subunit (δ-GABAA Rs) appears to be an important contributor to their behavioural effects. Here, we consider how neurosteroids acting upon GABAA Rs influence neuronal signalling, as well as how such effects may acutely and persistently influence behaviour, and explore the case for developing selective PAMs of δ-GABAA R subtypes for the treatment of psychiatric disorders.
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Affiliation(s)
- Delia Belelli
- Neuroscience, Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Grant D Phillips
- Neuroscience, Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - John R Atack
- Medicines Discovery Institute, Cardiff University, Cardiff, UK
| | - Jeremy J Lambert
- Neuroscience, Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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12
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Benfato ID, Quintanilha ACS, Henrique JS, Souza MA, Rosário BDA, Beserra Filho JIA, Santos RLO, Ribeiro AM, Le Sueur Maluf L, de Oliveira CAM. Effects of long-term social isolation on central, behavioural and metabolic parameters in middle-aged mice. Behav Brain Res 2022; 417:113630. [PMID: 34656691 PMCID: PMC8516156 DOI: 10.1016/j.bbr.2021.113630] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 12/27/2022]
Abstract
Social isolation gained discussion momentum due to the COVID-19 pandemic. Whereas many studies address the effects of long-term social isolation in post-weaning and adolescence and for periods ranging from 4 to 12 weeks, little is known about the repercussions of adult long-term social isolation in middle age. Thus, our aim was to investigate how long-term social isolation can influence metabolic, behavioural, and central nervous system-related areas in middle-aged mice. Adult male C57Bl/6 mice (4 months-old) were randomly divided into Social (2 cages, n = 5/cage) and Isolated (10 cages, n = 1/cage) housing groups, totalizing 30 weeks of social isolation, which ended concomitantly with the onset of middle age of mice. At the end of the trial, metabolic parameters, short-term memory, anxiety-like behaviour, and physical activity were assessed. Immunohistochemistry in the hippocampus (ΔFosB, BDNF, and 8OHDG) and hypothalamus (ΔFosB) was also performed. The Isolated group showed impaired memory along with a decrease in hippocampal ΔFosB at dentate gyrus and in BDNF at CA3. Food intake was also affected, but the direction depended on how it was measured in the Social group (individually or in the group) with no alteration in ΔFosB at the hypothalamus. Physical activity parameters increased with chronic isolation, but in the light cycle (inactive phase), with some evidence of anxiety-like behaviour. Future studies should better explore the timepoint at which the alterations found begin. In conclusion, long-term social isolation in adult mice contributes to alterations in feeding, physical activity pattern, and anxiety-like behaviour. Moreover, short-term memory deficit was associated with lower levels of hippocampal ΔFosB and BDNF in middle age.
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Affiliation(s)
- Izabelle Dias Benfato
- Interdisciplinary Graduate Program in Health Sciences, Federal University of Sao Paulo (UNIFESP), Brazil
| | | | - Jessica Salles Henrique
- Neurology / Neuroscience Graduate Program, Federal University of Sao Paulo (UNIFESP), Brazil
| | - Melyssa Alves Souza
- Interdisciplinary Graduate Program in Health Sciences, Federal University of Sao Paulo (UNIFESP), Brazil
| | - Barbara Dos Anjos Rosário
- Interdisciplinary Graduate Program in Health Sciences, Federal University of Sao Paulo (UNIFESP), Brazil
| | | | | | - Alessandra Mussi Ribeiro
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo (UNIFESP), Brazil
| | - Luciana Le Sueur Maluf
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo (UNIFESP), Brazil
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13
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Qin X, Pan HQ, Huang SH, Zou JX, Zheng ZH, Liu XX, You WJ, Liu ZP, Cao JL, Zhang WH, Pan BX. GABA A(δ) receptor hypofunction in the amygdala-hippocampal circuit underlies stress-induced anxiety. Sci Bull (Beijing) 2022; 67:97-110. [PMID: 36545966 DOI: 10.1016/j.scib.2021.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/07/2021] [Accepted: 09/07/2021] [Indexed: 01/06/2023]
Abstract
Dysregulated GABAergic inhibition in the amygdala has long been implicated in stress-related neuropsychiatric disorders. However, the molecular and circuit mechanisms underlying the dysregulation remain elusive. Here, by using a mouse model of chronic social defeat stress (CSDS), we observed that the dysregulation varied drastically across individual projection neurons (PNs) in the basolateral amygdala (BLA), one of the kernel amygdala subregions critical for stress coping. While persistently reducing the extrasynaptic GABAA receptor (GABAAR)-mediated tonic current in the BLA PNs projecting to the ventral hippocampus (BLA → vHPC PNs), CSDS increased the current in those projecting to the anterodorsal bed nucleus of stria terminalis (BLA → adBNST PNs), suggesting projection-based dysregulation of tonic inhibition in BLA PNs by CSDS. Transcriptional and electrophysiological analysis revealed that the opposite CSDS influences were mediated by loss- and gain-of-function of δ-containing GABAARs (GABAA(δ)Rs) in BLA → vHPC and BLA → adBNST PNs, respectively. Importantly, it was the lost inhibition in the former population but not the augmentation in the latter population that correlated with the increased anxiety-like behavior in CSDS mice. Virally mediated maintenance of GABAA(δ)R currents in BLA → vHPC PNs occluded CSDS-induced anxiety-like behavior. These findings clarify the molecular substrate for the dysregulated GABAergic inhibition in amygdala circuits for stress-associated psychopathology.
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Affiliation(s)
- Xia Qin
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China; Jiangsu Provincial Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou 221004, China
| | - Han-Qing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Shou-He Huang
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Jia-Xin Zou
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Zhi-Heng Zheng
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Xiao-Xuan Liu
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Wen-Jie You
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Zhi-Peng Liu
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Jun-Li Cao
- Jiangsu Provincial Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou 221004, China
| | - Wen-Hua Zhang
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China; Department of Biological Science, School of Life Science, Nanchang University, Nanchang 330031, China.
| | - Bing-Xing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China; Department of Biological Science, School of Life Science, Nanchang University, Nanchang 330031, China; Department of Ophthalmology, The Second Affiliated Hospital, Medical School of Nanchang University, Nanchang 330031, China.
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14
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Niedzwiedz-Massey VM, Douglas JC, Rafferty T, Wight PA, Kane CJM, Drew PD. Ethanol modulation of hippocampal neuroinflammation, myelination, and neurodevelopment in a postnatal mouse model of fetal alcohol spectrum disorders. Neurotoxicol Teratol 2021; 87:107015. [PMID: 34256161 PMCID: PMC8440486 DOI: 10.1016/j.ntt.2021.107015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 01/15/2023]
Abstract
Fetal alcohol spectrum disorders (FASD) are alarmingly common and result in significant personal and societal loss. Neuropathology of the hippocampus is common in FASD leading to aberrant cognitive function. In the current study, we evaluated the effects of ethanol on the expression of a targeted set of molecules involved in neuroinflammation, myelination, neurotransmission, and neuron function in the developing hippocampus in a postnatal model of FASD. Mice were treated with ethanol from P4-P9, hippocampi were isolated 24 h after the final treatment at P10, and mRNA levels were quantitated by qRT-PCR. We evaluated the effects of ethanol on both pro-inflammatory and anti-inflammatory molecules in the hippocampus and identified novel mechanisms by which ethanol induces neuroinflammation. We further demonstrated that ethanol decreased expression of molecules associated with mature oligodendrocytes and greatly diminished expression of a lacZ reporter driven by the first half of the myelin proteolipid protein (PLP) gene (PLP1). In addition, ethanol caused a decrease in genes expressed in oligodendrocyte progenitor cells (OPCs). Together, these studies suggest ethanol may modulate pathogenesis in the developing hippocampus through effects on cells of the oligodendrocyte lineage, resulting in altered oligodendrogenesis and myelination. We also observed differential expression of molecules important in synaptic plasticity, neurogenesis, and neurotransmission. Collectively, the molecules evaluated in these studies may play a role in ethanol-induced pathology in the developing hippocampus and contribute to cognitive impairment associated with FASD. A better understanding of these molecules and their effects on the developing hippocampus may lead to novel treatment strategies for FASD.
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Affiliation(s)
- Victoria M Niedzwiedz-Massey
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - James C Douglas
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Tonya Rafferty
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Patricia A Wight
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Cynthia J M Kane
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Paul D Drew
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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15
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Ghit A, Assal D, Al-Shami AS, Hussein DEE. GABA A receptors: structure, function, pharmacology, and related disorders. J Genet Eng Biotechnol 2021; 19:123. [PMID: 34417930 PMCID: PMC8380214 DOI: 10.1186/s43141-021-00224-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/08/2021] [Indexed: 02/03/2023]
Abstract
Background γ-Aminobutyric acid sub-type A receptors (GABAARs) are the most prominent inhibitory neurotransmitter receptors in the CNS. They are a family of ligand-gated ion channel with significant physiological and therapeutic implications. Main body GABAARs are heteropentamers formed from a selection of 19 subunits: six α (alpha1-6), three β (beta1-3), three γ (gamma1-3), three ρ (rho1-3), and one each of the δ (delta), ε (epsilon), π (pi), and θ (theta) which result in the production of a considerable number of receptor isoforms. Each isoform exhibits distinct pharmacological and physiological properties. However, the majority of GABAARs are composed of two α subunits, two β subunits, and one γ subunit arranged as γ2β2α1β2α1 counterclockwise around the center. The mature receptor has a central chloride ion channel gated by GABA neurotransmitter and modulated by a variety of different drugs. Changes in GABA synthesis or release may have a significant effect on normal brain function. Furthermore, The molecular interactions and pharmacological effects caused by drugs are extremely complex. This is due to the structural heterogeneity of the receptors, and the existence of multiple allosteric binding sites as well as a wide range of ligands that can bind to them. Notably, dysfunction of the GABAergic system contributes to the development of several diseases. Therefore, understanding the relationship between GABAA receptor deficits and CNS disorders thus has a significant impact on the discovery of disease pathogenesis and drug development. Conclusion To date, few reviews have discussed GABAA receptors in detail. Accordingly, this review aims to summarize the current understanding of the structural, physiological, and pharmacological properties of GABAARs, as well as shedding light on the most common associated disorders.
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Affiliation(s)
- Amr Ghit
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy. .,Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.
| | - Dina Assal
- Department of Biotechnology, American University in Cairo (AUC), Cairo, Egypt
| | - Ahmed S Al-Shami
- Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.,Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Diaa Eldin E Hussein
- Animal Health Research Institute (AHRI), Agricultural Research Center (ARC), Port of Alexandria, Alexandria, Egypt
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16
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Peñaloza-Sancho V, Pérez-Valenzuela C, Gonzalez C, Jujihara G, Bustos P, Dagnino-Subiabre A. Cannabinoid receptor type 1 modulates the effects of polyunsaturated fatty acids on memory of stressed rats. Nutr Neurosci 2021; 24:583-600. [PMID: 31637966 DOI: 10.1080/1028415x.2019.1659561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Memory and GABAergic activity in the hippocampus of stressed rats improve after n-3 polyunsaturated fatty acid (PUFA) supplementation. On the other hand, cannabinoid receptor type 1 (CB1) strongly regulates inhibitory neurotransmission in the hippocampus. Speculation about a possible relation between stress, endocannabinoids, and PUFAs. Here, we examined whether the effects of PUFAs on memory of chronically stressed rats depends on pharmacological manipulation of CB1 receptors. Male Sprague-Dawley rats were orally supplemented with n-3 (fish oil) or n-6 (primrose oil) PUFAs during chronic restraint stress (CRS) protocol (6 h/day; 21 days). First, we studied if the expression of CB1 receptors in the hippocampus may be affected by CRS and PUFAs supplementation by real-time PCR and immunofluorescence. CRS up-regulated the CB1 expression compared with the non-stressed rats, while only n-3 PUFAs countered this effect. Memory was evaluated in the Morris water maze. Stressed rats were co-treated with PUFAs and/or modulators of CB1 receptor (AM251, antagonist, 0.3 mg/kg/day; WIN55,212-2, agonist, 0.5 mg/kg/day) by intraperitoneal injections. Memory improved in the stressed rats that were treated with AM251 and/or n-3 PUFAs. Supplementation with n-6 PUFAs did not affect memory of stressed rats, but co-treatment with AM251 improved it, while co-treatment with WIN55,212-2 did not affect memory. Our results demonstrate that activity of the CB1 receptors may modulate the effects of PUFAs on memory of stressed rats. This study suggests that endocannabinoids and PUFAs can both become a singular system by being self-regulated in limbic areas, so they control the effects of stress on the brain.
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Affiliation(s)
- Valentín Peñaloza-Sancho
- Laboratory of Stress Neurobiology, Institute of Physiology, Center for Neurobiology and Integrative Pathophysiology, Faculty of Sciences, Universidad de Valparaíso, Valparaíso, Chile
| | - Catherine Pérez-Valenzuela
- Laboratory of Stress Neurobiology, Institute of Physiology, Center for Neurobiology and Integrative Pathophysiology, Faculty of Sciences, Universidad de Valparaíso, Valparaíso, Chile
| | - Celindo Gonzalez
- Laboratory of Stress Neurobiology, Institute of Physiology, Center for Neurobiology and Integrative Pathophysiology, Faculty of Sciences, Universidad de Valparaíso, Valparaíso, Chile
| | - German Jujihara
- Laboratory of Stress Neurobiology, Institute of Physiology, Center for Neurobiology and Integrative Pathophysiology, Faculty of Sciences, Universidad de Valparaíso, Valparaíso, Chile
| | - Paulina Bustos
- PhD Program in Aquaculture, School of Marine Sciences, Pontifica Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Alexies Dagnino-Subiabre
- Laboratory of Stress Neurobiology, Institute of Physiology, Center for Neurobiology and Integrative Pathophysiology, Faculty of Sciences, Universidad de Valparaíso, Valparaíso, Chile
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17
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Reducing glutamic acid decarboxylase in the dorsal dentate gyrus attenuates juvenile stress induced emotional and cognitive deficits. Neurobiol Stress 2021; 15:100350. [PMID: 34150959 PMCID: PMC8193143 DOI: 10.1016/j.ynstr.2021.100350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/11/2021] [Accepted: 05/28/2021] [Indexed: 11/22/2022] Open
Abstract
A high degree of regional, temporal and molecular specificity is evident in the regulation of GABAergic signaling in stress-responsive circuitry, hampering the use of systemic GABAergic modulators for the treatment of stress-related psychopathology. Here we investigated the effectiveness of local intervention with the GABA synthetic enzymes GAD65 and GAD67 in the dorsal dentate gyrus (dDG) vs ventral DG (vDG) to alleviate anxiety-like behavior and stress-induced symptoms in the rat. We induced shRNA-mediated knock down of either GAD65 or GAD67 with lentiviral vectors microinjected into the dDG or vDG of young adult male rats and examined anxiety behavior, learning and memory performance. Subsequently we tested whether reducing GAD65 expression in the dDG would also confer resilience against juvenile stress-induced behavioral and physiological symptoms in adulthood. While knock down of either isoform in the vDG increased anxiety levels in the open field and the elevated plus maze tests, the knock down of GAD65, but not GAD67, in the dDG conferred a significant reduction in anxiety levels. Strikingly, this manipulation also attenuated juvenile stress evoked anxiety behavior, cognitive and synaptic plasticity impairments. Local GABAergic circuitry in the DG plays an important and highly region-specific role in control of emotional behavior and stress responding. Reduction of GAD65 expression in the dDG appears to provide resilience to juvenile stress-induced emotional and cognitive deficits, opening a new direction towards addressing a significant risk factor for developing stress and trauma-related psychopathologies later in life. GAD67/65 in the dorsal/ventral dentate gyrus differentially modulate anxiety. Reduced GAD65 expression in the dorsal dentate gyrus supports stress resilience. The dorsal dentate gyrus plays a key role in stress resilience.
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18
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Wyroślak M, Lebida K, Mozrzymas JW. Induction of Inhibitory Synaptic Plasticity Enhances Tonic Current by Increasing the Content of α5-Subunit Containing GABA A Receptors in Hippocampal Pyramidal Neurons. Neuroscience 2021; 467:39-46. [PMID: 34033868 DOI: 10.1016/j.neuroscience.2021.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022]
Abstract
It is known that besides synaptic inhibition, there is a persistent component of inhibitory drive mediated by tonic currents which is believed to mediate majority of the total inhibitory charge in hippocampal neurons. Tonic currents, depending on cell types, can be mediated by a variety of GABAA receptor (GABAAR) subtypes but in pyramidal neurons, α5-subunit containing receptors were found to be predominant. Importantly, α5-GABAARs were implicated in both inhibitory and excitatory synaptic plasticity as well as in a variety of cognitive tasks. In the present study, we asked whether the protocol that evokes NMDAR-dependent GABAergic inhibitory long-term potentiation (iLTP) also induces the plasticity of tonic inhibition in hippocampal pyramidal neurons. Our whole-cell patch-clamp recordings revealed that the induction of this type of iLTP is associated with a marked increase in tonic current. By using the specific inverse agonist of α5-containing GABAARs (L-655,709) we provide evidence that this plastic change in tonic current is correlated with an increased proportion of this type of GABAARs. On the contrary, the iLTP induction did not affect the tonic current potentiated by THIP, indicating that the pool of δ subunit-containing GABAARs receptors remains unaffected. We conclude that the α5-GABAARs-dependent plasticity of tonic inhibition is a novel dimension of the neuroplasticity of the inhibitory drive in the hippocampal principal neurons. Overall, α5-containing GABAARs emerge as key players in a variety of plasticity mechanisms operating over a large span of time and spatial scales.
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Affiliation(s)
- Marcin Wyroślak
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland.
| | - Katarzyna Lebida
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland
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19
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Lin YF, Wang LY, Chen CS, Li CC, Hsiao YH. Cellular senescence as a driver of cognitive decline triggered by chronic unpredictable stress. Neurobiol Stress 2021; 15:100341. [PMID: 34095365 PMCID: PMC8163993 DOI: 10.1016/j.ynstr.2021.100341] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 12/13/2022] Open
Abstract
When an individual is under stress, the undesired effect on the brain often exceeds expectations. Additionally, when stress persists for a long time, it can trigger serious health problems, particularly depression. Recent studies have revealed that depressed patients have a higher rate of brain aging than healthy subjects and that depression increases dementia risk later in life. However, it remains unknown which factors are involved in brain aging triggered by chronic stress. The most critical change during brain aging is the decline in cognitive function. In addition, cellular senescence is a stable state of cell cycle arrest that occurs because of damage and/or stress and is considered a sign of aging. We used the chronic unpredictable stress (CUS) model to mimic stressful life situations and found that, compared with nonstressed control mice, CUS-treated C57BL/6 mice exhibited depression-like behaviors and cognitive decline. Additionally, the protein expression of the senescence marker p16INK4a was increased in the hippocampus, and senescence-associated β-galactosidase (SA-β-gal)-positive cells were found in the hippocampal dentate gyrus (DG) in CUS-treated mice. Furthermore, the levels of SA-β-gal or p16INK4a were strongly correlated with the severity of memory impairment in CUS-treated mice, whereas clearing senescent cells using the pharmacological senolytic cocktail dasatinib plus quercetin (D + Q) alleviated CUS-induced cognitive deficits, suggesting that targeting senescent cells may be a promising candidate approach to study chronic stress-induced cognitive decline. Our findings open new avenues for stress-related research and provide new insight into the association of chronic stress-induced cellular senescence with cognitive deficits.
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Affiliation(s)
- Yu-Fen Lin
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Li-Yun Wang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chi-Sheng Chen
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chia-Chun Li
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ya-Hsin Hsiao
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Behavioral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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20
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Wang FX, Tang RQ, Lv J, Xiao B, Li YS, Jin QH. Norepinephrine in the dentate gyrus is involved in spatial learning and memory alteration induced by chronic restraint stress in aged rats. Neuroreport 2020; 31:1308-1314. [PMID: 33165197 DOI: 10.1097/wnr.0000000000001547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The role of norepinephrine of the hippocampal dentate gyrus in spatial learning and memory alteration induced by chronic restraint stress (CRS, 3 h/day, 6 weeks) was investigated in aged rats. Spatial learning and memory were assessed by the Morris water maze (MWM), and the extracellular concentration of norepinephrine and amplitude of field excitatory postsynaptic potential (fEPSP) were measured in the dentate gyrus during MWM test in freely-moving rats. Next, the involvement of β-adrenoceptors in spatial learning and memory of CRS rats was examined by microinjection of its antagonist (propranolol) into the dentate gyrus. In addition, we observed the expression of brain-derived neurotrophic factor (BDNF) protein and activation of cAMP-response element binding protein (CREB) in the dentate gyrus. Compared with the control group, the basal level of norepinephrine, BDNF expression and CREB activation in the dentate gyrus were increased, and the spatial learning and memory abilities were enhanced in CRS rats. In the control group, the norepinephrine concentration and fEPSP amplitude in the dentate gyrus were increased on the second to fourth days of MWM test, and these responses were significantly enhanced in CRS rats. Furthermore, in CRS rats, propranolol significantly decreased the spatial learning and memory abilities, and attenuated the fEPSP response during MWM test, and the BDNF expression and CREB activation in the dentate gyrus. Our results suggest that norepinephrine activation of β-adrenoceptors in the hippocampal dentate gyrus is involved in spatial learning and memory enhancement induced by CRS in aged rats, in part via modulations of synaptic efficiency and CREB-BDNF signaling pathway.
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Affiliation(s)
- Fei-Xue Wang
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Ruo-Qi Tang
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Jing Lv
- Department of Physiology, Medical College, Hebei University of Engineering, Handan, Hebei Province, China
| | - Bin Xiao
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Ying-Shun Li
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Qing-Hua Jin
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
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21
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Serratto GM, Pizzi E, Murru L, Mazzoleni S, Pelucchi S, Marcello E, Mazzanti M, Passafaro M, Bassani S. The Epilepsy-Related Protein PCDH19 Regulates Tonic Inhibition, GABA AR Kinetics, and the Intrinsic Excitability of Hippocampal Neurons. Mol Neurobiol 2020; 57:5336-5351. [PMID: 32880860 PMCID: PMC7541378 DOI: 10.1007/s12035-020-02099-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/25/2020] [Indexed: 12/19/2022]
Abstract
PCDH19 encodes for protocadherin-19 (PCDH19), a cell-adhesion molecule of the cadherin superfamily preferentially expressed in the brain. PCDH19 mutations cause a neurodevelopmental syndrome named epileptic encephalopathy, early infantile, 9 (EIEE9) characterized by seizures associated with cognitive and behavioral deficits. We recently reported that PCDH19 binds the alpha subunits of GABAA receptors (GABAARs), modulating their surface availability and miniature inhibitory postsynaptic currents (mIPSCs). Here, we investigated whether PCDH19 regulatory function on GABAARs extends to the extrasynaptic receptor pool that mediates tonic current. In fact, the latter shapes neuronal excitability and network properties at the base of information processing. By combining patch-clamp recordings in whole-cell and cell-attached configurations, we provided a functional characterization of primary hippocampal neurons from embryonic rats of either sex expressing a specific PCDH19 short hairpin (sh)RNA. We first demonstrated that PCDH19 downregulation reduces GABAAR-mediated tonic current, evaluated by current shift and baseline noise analysis. Next, by single-channel recordings, we showed that PCDH19 regulates GABAARs kinetics without altering their conductance. In particular, GABAARs of shRNA-expressing neurons preferentially exhibit brief openings at the expense of long ones, thus displaying a flickering behavior. Finally, we showed that PCDH19 downregulation reduces the rheobase and increases the frequency of action potential firing, thus indicating neuronal hyperexcitability. These findings establish PCDH19 as a critical determinant of GABAAR-mediated tonic transmission and GABAARs gating, and provide the first mechanistic insights into PCDH19-related hyperexcitability and comorbidities.
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Affiliation(s)
| | - Erika Pizzi
- Department of Bioscience, University of Milan, 20133, Milan, Italy
| | - Luca Murru
- Institute of Neuroscience, CNR, 20129, Milan, Italy.,NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milan, Italy
| | - Sara Mazzoleni
- Institute of Neuroscience, CNR, 20129, Milan, Italy.,Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129, Milan, Italy
| | - Silvia Pelucchi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Michele Mazzanti
- Department of Bioscience, University of Milan, 20133, Milan, Italy
| | - Maria Passafaro
- Institute of Neuroscience, CNR, 20129, Milan, Italy.,NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milan, Italy
| | - Silvia Bassani
- Institute of Neuroscience, CNR, 20129, Milan, Italy. .,NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milan, Italy.
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Hippocampal µ-opioid receptors on GABAergic neurons mediate stress-induced impairment of memory retrieval. Mol Psychiatry 2020; 25:977-992. [PMID: 31142818 PMCID: PMC7192851 DOI: 10.1038/s41380-019-0435-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 04/18/2019] [Accepted: 04/29/2019] [Indexed: 01/28/2023]
Abstract
Stressful life events induce abnormalities in emotional and cognitive behaviour. The endogenous opioid system plays an essential role in stress adaptation and coping strategies. In particular, the µ-opioid receptor (μR), one of the major opioid receptors, strongly influences memory processing in that alterations in μR signalling are associated with various neuropsychiatric disorders. However, it remains unclear whether μR signalling contributes to memory impairments induced by acute stress. Here, we utilized pharmacological methods and cell-type-selective/non-cell-type-selective μR depletion approaches combined with behavioural tests, biochemical analyses, and in vitro electrophysiological recordings to investigate the role of hippocampal μR signalling in memory-retrieval impairment induced by acute elevated platform (EP) stress in mice. Biochemical and molecular analyses revealed that hippocampal μRs were significantly activated during acute stress. Blockage of hippocampal μRs, non-selective deletion of μRs or selective deletion of μRs on GABAergic neurons (μRGABA) reversed EP-stress-induced impairment of memory retrieval, with no effect on the elevation of serum corticosterone after stress. Electrophysiological results demonstrated that stress depressed hippocampal GABAergic synaptic transmission to CA1 pyramidal neurons, thereby leading to excitation/inhibition (E/I) imbalance in a μRGABA-dependent manner. Pharmaceutically enhancing hippocampal GABAA receptor-mediated inhibitory currents in stressed mice restored their memory retrieval, whereas inhibiting those currents in the unstressed mice mimicked the stress-induced impairment of memory retrieval. Our findings reveal a novel pathway in which endogenous opioids recruited by acute stress predominantly activate μRGABA to depress GABAergic inhibitory effects on CA1 pyramidal neurons, which subsequently alters the E/I balance in the hippocampus and results in impairment of memory retrieval.
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An Effect of Chronic Stress on Prospective Memory via Alteration of Resting-State Hippocampal Subregion Functional Connectivity. Sci Rep 2019; 9:19698. [PMID: 31873134 PMCID: PMC6928207 DOI: 10.1038/s41598-019-56111-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/29/2019] [Indexed: 12/16/2022] Open
Abstract
The alteration of hippocampal function by chronic stress impairs higher order cognitive functions such as prospective memory (PM). However, how chronic stress affects hippocampal subregions related to PM remains largely unknown. In this study, the altered functional network of hippocampal subregions related to PM in chronic stress was explored. College students (N = 21) completed PM tasks and resting-state functional magnetic resonance imaging scans one month prior to (baseline) and during the final examination week (chronic stress). Hippocampal subregions’ seed-based functional connectivity (FC) and PM were compared between baseline and chronic stress. PM performance declined in chronic stress. The FC of the cornu ammonis 2, 3 and dentate gyrus (CA23DG) with the bilateral caudate and precuneus was increased in chronic stress, while the FC of the subicular complex (SUBC) with the left middle frontal gyrus, the left inferior parietal gyrus and the right supramarginal gyrus was decreased. There was a negative correlation between PM performance and the FC of hippocampal subregions. We found chronic stress impairs PM by decreasing the FC of SUBC and increasing the FC of CA23DG. These findings suggest functional changes in hippocampal subregion networks as a mechanism underlying the impairment of PM in chronic stress.
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24
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Fan KM, Qiu LJ, Ma N, Du YN, Qian ZQ, Wei CL, Han J, Ren W, Shi MM, Liu ZQ. Acute Stress Facilitates LTD Induction at Glutamatergic Synapses in the Hippocampal CA1 Region by Activating μ-Opioid Receptors on GABAergic Neurons. Front Neurosci 2019; 13:71. [PMID: 30800053 PMCID: PMC6375894 DOI: 10.3389/fnins.2019.00071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/23/2019] [Indexed: 12/15/2022] Open
Abstract
Acute stress impairs recall memory through the facilitation of long-term depression (LTD) of hippocampal synaptic transmission. The endogenous opioid system (EOS) plays essential roles in stress-related emotional and physiological responses. Specifically, behavioral studies have shown that the impairment of memory retrieval induced by stressful events involves the activation of opioid receptors. However, it is unclear whether signaling mediated by μ-opioid receptors (μRs), one of the three major opioid receptors, participates in acute stress-related hippocampal LTD facilitation. Here, we examined the effects of a single elevated platform (EP) stress exposure on excitatory synaptic transmission and plasticity at the Schaffer collateral-commissural (SC) to CA1 synapses by recording electrically evoked field excitatory postsynaptic potentials and population spikes of hippocampal pyramidal neurons in anesthetized adult mice. EP stress exposure attenuated GABAergic feedforward and feedback inhibition of CA1 pyramidal neurons and facilitated low-frequency stimulation (LFS)-induced long-term depression (LTD) at SC-CA1 glutamatergic synapses. These effects were reproduced by exogenously activating μRs in unstressed mice. The specific deletion of μRs on GABAergic neurons (μRGABA) not only prevented the EP stress-induced memory impairment but also reversed the EP stress-induced attenuation of GABAergic inhibition and facilitation of LFS-LTD. Our results suggest that acute stress endogenously activates μRGABA to attenuate hippocampal GABAergic signaling, thereby facilitating LTD induction at excitatory synapses and eliciting memory impairments.
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Affiliation(s)
- Ka-Min Fan
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Li-Juan Qiu
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Ning Ma
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Yi-Nan Du
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Zhao-Qiang Qian
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Chun-Ling Wei
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Jing Han
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Wei Ren
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Mei-Mei Shi
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
| | - Zhi-Qiang Liu
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, Xi'an, China
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25
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Ratner MH, Kumaresan V, Farb DH. Neurosteroid Actions in Memory and Neurologic/Neuropsychiatric Disorders. Front Endocrinol (Lausanne) 2019; 10:169. [PMID: 31024441 PMCID: PMC6465949 DOI: 10.3389/fendo.2019.00169] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 02/28/2019] [Indexed: 12/24/2022] Open
Abstract
Memory dysfunction is a symptomatic feature of many neurologic and neuropsychiatric disorders; however, the basic underlying mechanisms of memory and altered states of circuitry function associated with disorders of memory remain a vast unexplored territory. The initial discovery of endogenous neurosteroids triggered a quest to elucidate their role as neuromodulators in normal and diseased brain function. In this review, based on the perspective of our own research, the advances leading to the discovery of positive and negative neurosteroid allosteric modulators of GABA type-A (GABAA), NMDA, and non-NMDA type glutamate receptors are brought together in a historical and conceptual framework. We extend the analysis toward a state-of-the art view of how neurosteroid modulation of neural circuitry function may affect memory and memory deficits. By aggregating the results from multiple laboratories using both animal models for disease and human clinical research on neuropsychiatric and age-related neurodegenerative disorders, elements of a circuitry level view begins to emerge. Lastly, the effects of both endogenously active and exogenously administered neurosteroids on neural networks across the life span of women and men point to a possible underlying pharmacological connectome by which these neuromodulators might act to modulate memory across diverse altered states of mind.
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26
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Novais A, Silva A, Ferreira AC, Falcão AM, Sousa N, Palha JA, Marques F, Sousa JC. Adult Hippocampal Neurogenesis Modulation by the Membrane-Associated Progesterone Receptor Family Member Neudesin. Front Cell Neurosci 2018; 12:463. [PMID: 30534059 PMCID: PMC6275434 DOI: 10.3389/fncel.2018.00463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Neudesin (Neuron-derived neurotrophic factor, NENF), a membrane-associated progesterone receptor family (MAPR) member, is a neuron secreted protein with neurotrophic properties during embryonic stages. However, its role in the adult brain is still poorly addressed. In this study we have used neudesin-null (Nenf−/−) mice and performed a characterization of the proliferation state of the adult neurogenic niches, the adult subventricular zone (SVZ) and the hippocampus subgranular zone (SGZ). Nenf−/− males did not presented any deficits in proliferation in the SVZ neither in vivo nor in vitro. On the other hand a decrease in cell proliferation in the SGZ was observed, as well as a decrease in the number of newborn neurons in the dentate gyrus (DG) that was accompanied by impaired context discrimination in a contextual fear conditioning (CFC) task. Since NENF neurotrophic action is suggested to occur via the formation of a progesterone stability complex for the activation of non-genomic cascade, we further evaluated progesterone metabolism in the absence of NENF. Interestingly, expression of progesterone catabolic rate-determining enzyme, 5-α-reductase was upregulated in the DG of Nenf−/−, together with a significant increase in the expression of the δGABAA receptor gene, involved in DG tonic inhibition. Taken together, these findings add in vivo evidence on the neurotrophic properties of NENF in the adult brain. Furthermore, the mechanism of action of NENF in this process might implicate neurosteroids modulation, at least in the DG.
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Affiliation(s)
- Ashley Novais
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - Alberto Silva
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - Ana Catarina Ferreira
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - Ana Mendanha Falcão
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - Joana Almeida Palha
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - Fernanda Marques
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - João Carlos Sousa
- Life and Health Sciences Research Institute (ICVS), Neuroscience Domain, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
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27
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Zheng C, Huang Y, Zhang H, Zha Y, Wang M. [β2-nicotinic acetylcholine receptor promotes development of GABA A receptors in mouse hippocampal CA1 and CA3 pyramidal neurons]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2018; 38:1045-1051. [PMID: 30377105 DOI: 10.12122/j.issn.1673-4254.2018.09.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To explore the role of β2-nicotinic acetylcholine receptor (β2-nAChR) in the development of γ- aminobutyric acid A type receptors (GABAA-Rs) in hippocampal CA1 and CA3 pyramidal neurons of mice. METHODS The hippocampal CA1 and CA3 pyramidal neurons were acutely isolated from β2-nAChR gene knockout (β2-KO group) mice. GABA currents in CA1 and CA3 pyramidal neurons were induced with the selective GABAA-R agonist muscimol and recorded using perforated patch-clamp recording technique. The GABA currents of CA1 and CA3 pyramidal neurons were tested for their equilibrium potentials (EMuss) and kinetic parameters and were compared with the measurements in wild-type mice (WT group). RESULTS The mean EMus of CA1 neurons (n=7) of β2-KO mice (n=4) was -31.7±3.5 mV, showing an obvious depolarizing shift compared with the WT mice (P < 0.05); the mean EMus of CA3 neurons (n=4) was -16.1±4.6 mV, also showing a depolarizing shift (P < 0.01). The difference in the EMuss between CA3 and CA1 neurons in β2-KO mice, but not in WT mice, was significant (P < 0.05). The GABAA-R desensitization was significantly slowed down in both CA1 and CA3 neurons of β2-KO mice, with decay time of 2.2±0.2 s and 3.2±0.1 s, respectively, significantly longer than those in WT mice (1.6±0.1 s and 2.3±0.1 s, respectively; P < 0.05). CONCLUSIONS β2-containing nAChRs may promote the functional maturation of GABAA-R in CA1 and CA3 pyramidal cells in mouse hippocampus.
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Affiliation(s)
- Chao Zheng
- Cell Electrophysiology Laboratory, Wannan Medical College, Wuhu 241002, China
| | - Yan Huang
- Cell Electrophysiology Laboratory, Wannan Medical College, Wuhu 241002, China
| | - Huanhuan Zhang
- Cell Electrophysiology Laboratory, Wannan Medical College, Wuhu 241002, China
| | - Yingying Zha
- Cell Electrophysiology Laboratory, Wannan Medical College, Wuhu 241002, China
| | - Mengya Wang
- Cell Electrophysiology Laboratory, Wannan Medical College, Wuhu 241002, China
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28
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Siivonen MS, de Miguel E, Aaltio J, Manner AK, Vahermo M, Yli-Kauhaluoma J, Linden AM, Aitta-Aho T, Korpi ER. Conditioned Reward of Opioids, but not Psychostimulants, is Impaired in GABA-A Receptor δ Subunit Knockout Mice. Basic Clin Pharmacol Toxicol 2018; 123:558-566. [PMID: 29781560 DOI: 10.1111/bcpt.13043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/07/2018] [Indexed: 12/17/2022]
Abstract
Extrasynaptic δ subunit-containing γ-aminobutyric acid type A receptors (δ-GABAA Rs) are emerging as targets for a number of neuropsychopharmacological drugs, including the direct GABA site agonist gaboxadol and neuroactive steroids. Among other regions, these δ-GABAA Rs are functionally expressed in the ventral tegmental area (VTA), the cell body region of mesocorticolimbic dopamine (DA) system important for motivated behaviours, and in the target region, the nucleus accumbens. Gaboxadol and neurosteroids induce VTA DA neuron plasticity ex vivo, by inhibiting the VTA GABA neurons, and aversive place conditioning, which are absent in the δ-GABAA R knockout mice (δ-KO). It is not known whether δ-GABAA Rs are important for the effects of other drugs, such as opioids (that also inhibit GABA neurons) and stimulants (that primarily elevate monoamine levels). Here, we used δ-KO mice and conditioned place preference (CPP) test to study the rewarding effects of morphine (20 mg/kg), methamphetamine (1 mg/kg) and mephedrone (5 mg/kg). Morphine-induced nociception was also assessed using tail-flick and hot-plate tests. We found that the δ-KO mice failed to express morphine-induced CPP, but that they were more sensitive to morphine-induced analgesia in the tail-flick test. In contrast, stimulant-induced CPP in the δ-KO mice was similar to that in the wild-type controls. Thus, the conditioned rewarding effect by opioids, but not that of stimulants, was impaired in the absence of δ-GABAA Rs. Further studies are warranted to assess the potential of δ-GABAA R antagonists as possible targets for reducing morphine reward and potentiating morphine analgesia.
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Affiliation(s)
- Milo S Siivonen
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Juho Aaltio
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Aino K Manner
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikko Vahermo
- Drug Discovery Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Jari Yli-Kauhaluoma
- Drug Discovery Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Teemu Aitta-Aho
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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29
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Czéh B, Vardya I, Varga Z, Febbraro F, Csabai D, Martis LS, Højgaard K, Henningsen K, Bouzinova EV, Miseta A, Jensen K, Wiborg O. Long-Term Stress Disrupts the Structural and Functional Integrity of GABAergic Neuronal Networks in the Medial Prefrontal Cortex of Rats. Front Cell Neurosci 2018; 12:148. [PMID: 29973870 PMCID: PMC6020798 DOI: 10.3389/fncel.2018.00148] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 05/14/2018] [Indexed: 12/12/2022] Open
Abstract
Clinical and experimental data suggest that fronto-cortical GABAergic deficits contribute to the pathophysiology of major depressive disorder (MDD). To further test this hypothesis, we used a well characterized rat model for depression and examined the effect of stress on GABAergic neuron numbers and GABA-mediated synaptic transmission in the medial prefrontal cortex (mPFC) of rats. Adult male Wistar rats were subjected to 9-weeks of chronic mild stress (CMS) and based on their hedonic-anhedonic behavior they were behaviorally phenotyped as being stress-susceptible (anhedonic) or stress-resilient. Post mortem quantitative histopathology was used to examine the effect of stress on parvalbumin (PV)-, calretinin- (CR), calbindin- (CB), cholecystokinin- (CCK), somatostatin-(SST) and neuropeptide Y-positive (NPY+) GABAergic neuron numbers in all cortical subareas of the mPFC (anterior cingulate (Cg1), prelimbic (PrL) and infralimbic (IL) cortexes). In vitro, whole-cell patch-clamp recordings from layer II–III pyramidal neurons of the ventral mPFC was used to examine GABAergic neurotransmission. The cognitive performance of the animals was assessed in a hippocampal-prefrontal-cortical circuit dependent learning task. Stress exposure reduced the number of CCK-, CR- and PV-positive GABAergic neurons in the mPFC, most prominently in the IL cortex. Interestingly, in the stress-resilient animals, we found higher number of neuropeptide Y-positive neurons in the entire mPFC. The electrophysiological analysis revealed reduced frequencies of spontaneous and miniature IPSCs in the anhedonic rats and decreased release probability of perisomatic-targeting GABAergic synapses and alterations in GABAB receptor mediated signaling. In turn, pyramidal neurons showed higher excitability. Anhedonic rats were also significantly impaired in the object-place paired-associate learning task. These data demonstrate that long-term stress results in functional and structural deficits of prefrontal GABAergic networks. Our findings support the concept that fronto-limbic GABAergic dysfunctions may contribute to emotional and cognitive symptoms of MDD.
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Affiliation(s)
- Boldizsár Czéh
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark.,Neurobiology of Stress Research Group, János Szentágothai Research Centre & Centre for Neuroscience, Pécs, Hungary.,Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, Hungary
| | - Irina Vardya
- Synaptic Physiology Laboratory, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Zsófia Varga
- Neurobiology of Stress Research Group, János Szentágothai Research Centre & Centre for Neuroscience, Pécs, Hungary
| | - Fabia Febbraro
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Dávid Csabai
- Neurobiology of Stress Research Group, János Szentágothai Research Centre & Centre for Neuroscience, Pécs, Hungary
| | | | | | - Kim Henningsen
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Elena V Bouzinova
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Attila Miseta
- Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, Hungary
| | - Kimmo Jensen
- Synaptic Physiology Laboratory, Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ove Wiborg
- Department of Clinical Medicine, Aarhus University, Risskov, Denmark.,Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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30
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McGarrity S, Mason R, Fone KC, Pezze M, Bast T. Hippocampal Neural Disinhibition Causes Attentional and Memory Deficits. Cereb Cortex 2018; 27:4447-4462. [PMID: 27550864 DOI: 10.1093/cercor/bhw247] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 07/18/2016] [Indexed: 12/18/2022] Open
Abstract
Subconvulsive hippocampal neural disinhibition, that is reduced GABAergic inhibition, has been implicated in neuropsychiatric disorders characterized by attentional and memory deficits, including schizophrenia and age-related cognitive decline. Considering that neural disinhibition may disrupt both intra-hippocampal processing and processing in hippocampal projection sites, we hypothesized that hippocampal disinhibition disrupts hippocampus-dependent memory performance and, based on strong hippocampo-prefrontal connectivity, also prefrontal-dependent attention. In support of this hypothesis, we report that acute hippocampal disinhibition by microinfusion of the GABA-A receptor antagonist picrotoxin in rats impaired hippocampus-dependent everyday-type rapid place learning performance on the watermaze delayed-matching-to-place test and prefrontal-dependent attentional performance on the 5-choice-serial-reaction-time test, which does not normally require the hippocampus. For comparison, we also examined psychosis-related sensorimotor effects, using startle/prepulse inhibition (PPI) and locomotor testing. Hippocampal picrotoxin moderately increased locomotion and slightly reduced startle reactivity, without affecting PPI. In vivo electrophysiological recordings in the vicinity of the infusion site showed that picrotoxin mainly enhanced burst firing of hippocampal neurons. In conclusion, hippocampal neural disinhibition disrupts hippocampus-dependent memory performance and also manifests through deficits in not normally hippocampus-dependent attentional performance. These behavioral deficits may reflect a disrupted control of burst firing, which may disrupt hippocampal processing and cause aberrant drive to hippocampal projection sites.
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Affiliation(s)
- Stephanie McGarrity
- School of Psychology, University of Nottingham, Nottingham NG7 2RD, UK.,Neuroscience@Nottingham, University of Nottingham, Nottingham NG7 2RD, UK
| | - Rob Mason
- Neuroscience@Nottingham, University of Nottingham, Nottingham NG7 2RD, UK.,School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Kevin C Fone
- Neuroscience@Nottingham, University of Nottingham, Nottingham NG7 2RD, UK.,School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Marie Pezze
- School of Psychology, University of Nottingham, Nottingham NG7 2RD, UK.,Neuroscience@Nottingham, University of Nottingham, Nottingham NG7 2RD, UK
| | - Tobias Bast
- School of Psychology, University of Nottingham, Nottingham NG7 2RD, UK.,Neuroscience@Nottingham, University of Nottingham, Nottingham NG7 2RD, UK
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31
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An Emerging Circuit Pharmacology of GABA A Receptors. Trends Pharmacol Sci 2018; 39:710-732. [PMID: 29903580 DOI: 10.1016/j.tips.2018.04.003] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/23/2018] [Accepted: 04/17/2018] [Indexed: 12/21/2022]
Abstract
In the past 20 years we have learned a great deal about GABAA receptor (GABAAR) subtypes, and which behaviors are regulated or which drug effects are mediated by each subtype. However, the question of where GABAARs involved in specific drug effects and behaviors are located in the brain remains largely unanswered. We review here recent studies taking a circuit pharmacology approach to investigate the functions of GABAAR subtypes in specific brain circuits controlling fear, anxiety, learning, memory, reward, addiction, and stress-related behaviors. The findings of these studies highlight the complexity of brain inhibitory systems and the importance of taking a subtype-, circuit-, and neuronal population-specific approach to develop future therapeutic strategies using cell type-specific drug delivery.
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32
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Colmers PLW, Bains JS. Balancing tonic and phasic inhibition in hypothalamic corticotropin-releasing hormone neurons. J Physiol 2018; 596:1919-1929. [PMID: 29419884 DOI: 10.1113/jp275588] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/29/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS GABA transporter (GAT) blockade recruits extrasynaptic GABAA receptors (GABAA Rs) and amplifies constitutive presynaptic GABAB R activity. Extrasynaptic GABAA Rs contribute to a tonic current. Corticosteroids increase the tonic current mediated by extrasynaptic GABAA Rs. ABSTRACT Corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) are integratory hubs that regulate the endocrine response to stress. GABA inputs provide a basal inhibitory tone that constrains this system and circulating glucocorticoids (CORT) are important feedback controllers of CRH output. Surprisingly little is known about the direct effects of CORT on GABA synapses in PVN. Here we used whole-cell patch clamp recordings from CRH neurons in mouse hypothalamic brain slices to examine the effects of CORT on synaptic and extrasynaptic GABA signalling. We show that GABA transporters (GATs) limit constitutive activation of presynaptic GABAB receptors and ensure high release probability at GABA synapses. GATs in combination with GABAB receptors also curtail extrasynaptic GABAA R signalling. CORT has no effect on synaptic GABA signalling, but increases extrasynaptic GABA tone through upregulation of postsynaptic GABAA receptors. These data show that efficient GABA clearance and autoinhibition control the balance between synaptic (phasic) and extrasynaptic (tonic) inhibition in PVN CRH neurons. This balance is shifted towards increased extrasynaptic inhibition by CORT.
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Affiliation(s)
- Phillip L W Colmers
- Hotchkiss Brain Institute and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Jaideep S Bains
- Hotchkiss Brain Institute and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
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33
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Furukawa M, Tsukahara T, Tomita K, Iwai H, Sonomura T, Miyawaki S, Sato T. Neonatal maternal separation delays the GABA excitatory-to-inhibitory functional switch by inhibiting KCC2 expression. Biochem Biophys Res Commun 2017; 493:1243-1249. [PMID: 28962859 DOI: 10.1016/j.bbrc.2017.09.143] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 09/26/2017] [Indexed: 12/23/2022]
Abstract
The excitatory-to-inhibitory functional switch of γ-aminobutyric acid (GABA; GABA switch), which normally occurs in the first to the second postnatal week in the hippocampus, is necessary for the development of appropriate central nervous system function. A deficit in GABAergic inhibitory function could cause excitatory/inhibitory (E/I) neuron imbalance that is found in many neurodegenerative disorders. In the present study, we examined whether neonatal stress can affect the timing of the GABA functional switch and cause disorders during adolescence. Neonatal stress was induced in C57BL/6J male mouse pups by maternal separation (MS) on postnatal days (PND) 1-21. Histological quantification of K+-Cl- co-transporter (KCC2) and Ca2+ imaging were performed to examine the timing of the GABA switch during the MS period. To evaluate the influence of neonatal MS on adolescent hippocampal function, we quantified KCC2 expression and evaluated hippocampal-related behavioral tasks at PND35-38. We showed that MS delayed the timing of the GABA switch in the hippocampus and inhibited the increase in membrane KCC2 expression, with KCC2 expression inhibition persisting until adolescence. Behavioral tests showed impaired cognition, declined attention, hyperlocomotion, and aggressive character in maternally separated mice. Taken together, our results show that neonatal stress delayed the timing of the GABA switch, which could change the E/I balance and cause neurodegenerative disorders in later life.
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Affiliation(s)
- Minami Furukawa
- Department of Applied Pharmacology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan; Department of Orthodontics and Dentofacial Orthopedics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Takao Tsukahara
- Department of Applied Pharmacology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Kazuo Tomita
- Department of Applied Pharmacology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Haruki Iwai
- Department of Oral Anatomy and Cell Biology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Takahiro Sonomura
- Department of Oral Anatomy, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0226, Japan
| | - Shouichi Miyawaki
- Department of Orthodontics and Dentofacial Orthopedics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Tomoaki Sato
- Department of Applied Pharmacology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.
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34
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Decreased surface expression of the δ subunit of the GABA A receptor contributes to reduced tonic inhibition in dentate granule cells in a mouse model of fragile X syndrome. Exp Neurol 2017; 297:168-178. [PMID: 28822839 DOI: 10.1016/j.expneurol.2017.08.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/21/2017] [Accepted: 08/15/2017] [Indexed: 11/22/2022]
Abstract
While numerous changes in the GABA system have been identified in models of Fragile X Syndrome (FXS), alterations in subunits of the GABAA receptors (GABAARs) that mediate tonic inhibition are particularly intriguing. Considering the key role of tonic inhibition in controlling neuronal excitability, reduced tonic inhibition could contribute to FXS-associated disorders such as hyperactivity, hypersensitivity, and increased seizure susceptibility. The current study has focused on the expression and function of the δ subunit of the GABAAR, a major subunit involved in tonic inhibition, in granule cells of the dentate gyrus in the Fmr1 knockout (KO) mouse model of FXS. Electrophysiological studies of dentate granule cells revealed a marked, nearly four-fold, decrease in tonic inhibition in the Fmr1 KO mice, as well as reduced effects of two δ subunit-preferring pharmacological agents, THIP and DS2, supporting the suggestion that δ subunit-containing GABAARs are compromised in the Fmr1 KO mice. Immunohistochemistry demonstrated a small but statistically significant decrease in δ subunit labeling in the molecular layer of the dentate gyrus in Fmr1 KO mice compared to wildtype (WT) littermates. The discrepancy between the large deficits in GABA-mediated tonic inhibition in granule cells in the Fmr1 KO mice and only modest reductions in immunolabeling of the δ subunit led to studies of surface expression of the δ subunit. Cross-linking experiments followed by Western blot analysis demonstrated a small, non-significant decrease in total δ subunit protein in the hippocampus of Fmr1 KO mice, but a four-fold decrease in surface expression of the δ subunit in these mice. No significant changes were observed in total or surface expression of the α4 subunit protein, a major partner of the δ subunit in the forebrain. Postembedding immunogold labeling for the δ subunit demonstrated a large, three-fold, decrease in the number of symmetric synapses with immunolabeling at perisynaptic locations in Fmr1 KO mice. While α4 immunogold particles were also reduced at perisynaptic locations in the Fmr1 KO mice, the labeling was increased at synaptic sites. Together these findings suggest that, in the dentate gyrus, altered surface expression of the δ subunit, rather than a decrease in δ subunit expression alone, could be limiting δ subunit-mediated tonic inhibition in this model of FXS. Finding ways to increase surface expression of the δ subunit of the GABAAR could be a novel approach to treatment of hyperexcitability-related alterations in FXS.
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35
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Bast T, Pezze M, McGarrity S. Cognitive deficits caused by prefrontal cortical and hippocampal neural disinhibition. Br J Pharmacol 2017; 174:3211-3225. [PMID: 28477384 DOI: 10.1111/bph.13850] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/18/2017] [Accepted: 05/03/2017] [Indexed: 12/22/2022] Open
Abstract
We review recent evidence concerning the significance of inhibitory GABA transmission and of neural disinhibition, that is, deficient GABA transmission, within the prefrontal cortex and the hippocampus, for clinically relevant cognitive functions. Both regions support important cognitive functions, including attention and memory, and their dysfunction has been implicated in cognitive deficits characterizing neuropsychiatric disorders. GABAergic inhibition shapes cortico-hippocampal neural activity, and, recently, prefrontal and hippocampal neural disinhibition has emerged as a pathophysiological feature of major neuropsychiatric disorders, especially schizophrenia and age-related cognitive decline. Regional neural disinhibition, disrupting spatio-temporal control of neural activity and causing aberrant drive of projections, may disrupt processing within the disinhibited region and efferent regions. Recent studies in rats showed that prefrontal and hippocampal neural disinhibition (by local GABA antagonist microinfusion) dysregulates burst firing, which has been associated with important aspects of neural information processing. Using translational tests of clinically relevant cognitive functions, these studies showed that prefrontal and hippocampal neural disinhibition disrupts regional cognitive functions (including prefrontal attention and hippocampal memory function). Moreover, hippocampal neural disinhibition disrupted attentional performance, which does not require the hippocampus but requires prefrontal-striatal circuits modulated by the hippocampus. However, some prefrontal and hippocampal functions (including inhibitory response control) are spared by regional disinhibition. We consider conceptual implications of these findings, regarding the distinct relationships of distinct cognitive functions to prefrontal and hippocampal GABA tone and neural activity. Moreover, the findings support the proposition that prefrontal and hippocampal neural disinhibition contributes to clinically relevant cognitive deficits, and we consider pharmacological strategies for ameliorating cognitive deficits by rebalancing disinhibition-induced aberrant neural activity. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.
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Affiliation(s)
- Tobias Bast
- School of Psychology and Neuroscience @Nottingham, University of Nottingham, Nottingham, UK
| | - Marie Pezze
- School of Psychology and Neuroscience @Nottingham, University of Nottingham, Nottingham, UK
| | - Stephanie McGarrity
- School of Psychology and Neuroscience @Nottingham, University of Nottingham, Nottingham, UK
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Csabai D, Seress L, Varga Z, Ábrahám H, Miseta A, Wiborg O, Czéh B. Electron Microscopic Analysis of Hippocampal Axo-Somatic Synapses in a Chronic Stress Model for Depression. Hippocampus 2016; 27:17-27. [PMID: 27571571 PMCID: PMC5215622 DOI: 10.1002/hipo.22650] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2016] [Indexed: 01/01/2023]
Abstract
Stress can alter the number and morphology of excitatory synapses in the hippocampus, but nothing is known about the effect of stress on inhibitory synapses. Here, we used an animal model for depression, the chronic mild stress model, and quantified the number of perisomatic inhibitory neurons and their synapses. We found reduced density of parvalbumin‐positive (PV+) neurons in response to stress, while the density of cholecystokinin‐immunoreactive (CCK+) neurons was unaffected. We did a detailed electron microscopic analysis to quantify the frequency and morphology of perisomatic inhibitory synapses in the hippocampal CA1 area. We analyzed 1100 CA1 pyramidal neurons and 4800 perisomatic terminals in five control and four chronically stressed rats. In the control animals we observed the following parameters: Number of terminals/soma = 57; Number of terminals/100 µm cell perimeter = 10; Synapse/terminal ratio = 32%; Synapse number/100 terminal = 120; Average terminal length = 920nm. None of these parameters were affected by the stress exposure. Overall, these data indicate that despite the depressive‐like behavior and the decrease in the number of perisomatic PV+ neurons in the light microscopic preparations, the number of perisomatic inhibitory synapses on CA1 pyramidal cells was not affected by stress. In the electron microscope, PV+ neurons and the axon terminals appeared to be normal and we did not find any apoptotic or necrotic cells. This data is in sharp contrast to the remarkable remodeling of the excitatory synapses on spines that has been reported in response to stress and depressive‐like behavior. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Dávid Csabai
- MTA - PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, Pécs, 7624, Hungary
| | - László Seress
- Central Electron Microscope Laboratory, University of Pécs, Medical School, Pécs, 7624, Hungary
| | - Zsófia Varga
- MTA - PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, Pécs, 7624, Hungary
| | - Hajnalka Ábrahám
- Central Electron Microscope Laboratory, University of Pécs, Medical School, Pécs, 7624, Hungary.,Department of Medical Biology, University of Pécs, Medical School, Pécs, 7624, Hungary
| | - Attila Miseta
- Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, 7624, Hungary
| | - Ove Wiborg
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Boldizsár Czéh
- MTA - PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, Pécs, 7624, Hungary.,Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, 7624, Hungary.,Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
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