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Noradrenaline activation of hippocampal dopamine D 1 receptors promotes antidepressant effects. Proc Natl Acad Sci U S A 2022; 119:e2117903119. [PMID: 35939697 PMCID: PMC9388128 DOI: 10.1073/pnas.2117903119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dopamine D1 receptors (D1Rs) in the hippocampal dentate gyrus (DG) are essential for antidepressant effects. However, the midbrain dopaminergic neurons, the major source of dopamine in the brain, only sparsely project to DG, suggesting possible activation of DG D1Rs by endogenous substances other than dopamine. We have examined this possibility using electrophysiological and biochemical techniques and found robust activation of D1Rs in mouse DG neurons by noradrenaline. Noradrenaline at the micromolar range potentiated synaptic transmission at the DG output and increased the phosphorylation of protein kinase A substrates in DG via activation of D1Rs and β adrenergic receptors. Neuronal excitation preferentially enhanced noradrenaline-induced synaptic potentiation mediated by D1Rs with minor effects on β-receptor-dependent potentiation. Increased voluntary exercise by wheel running also enhanced noradrenaline-induced, D1R-mediated synaptic potentiation, suggesting a distinct functional role of the noradrenaline-D1R signaling. We then examined the role of this signaling in antidepressant effects using mice exposed to chronic restraint stress. In the stressed mice, an antidepressant acting on the noradrenergic system induced a mature-to-immature change in the DG neuron phenotype, a previously proposed cellular substrate for antidepressant action. This effect was evident only in mice subjected to wheel running and blocked by a D1R antagonist. These results suggest a critical role of noradrenaline-induced activation of D1Rs in antidepressant effects in DG. Experience-dependent regulation of noradrenaline-D1R signaling may determine responsiveness to antidepressant drugs in depressive disorders.
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Rapid Ca 2+ channel accumulation contributes to cAMP-mediated increase in transmission at hippocampal mossy fiber synapses. Proc Natl Acad Sci U S A 2021; 118:2016754118. [PMID: 33622791 DOI: 10.1073/pnas.2016754118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The cyclic adenosine monophosphate (cAMP)-dependent potentiation of neurotransmitter release is important for higher brain functions such as learning and memory. To reveal the underlying mechanisms, we applied paired pre- and postsynaptic recordings from hippocampal mossy fiber-CA3 synapses. Ca2+ uncaging experiments did not reveal changes in the intracellular Ca2+ sensitivity for transmitter release by cAMP, but suggested an increase in the local Ca2+ concentration at the release site, which was much lower than that of other synapses before potentiation. Total internal reflection fluorescence (TIRF) microscopy indicated a clear increase in the local Ca2+ concentration at the release site within 5 to 10 min, suggesting that the increase in local Ca2+ is explained by the simple mechanism of rapid Ca2+ channel accumulation. Consistently, two-dimensional time-gated stimulated emission depletion microscopy (gSTED) microscopy showed an increase in the P/Q-type Ca2+ channel cluster size near the release sites. Taken together, this study suggests a potential mechanism for the cAMP-dependent increase in transmission at hippocampal mossy fiber-CA3 synapses, namely an accumulation of active zone Ca2+ channels.
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Asada-Utsugi M, Uemura K, Kubota M, Noda Y, Tashiro Y, Uemura TM, Yamakado H, Urushitani M, Takahashi R, Hattori S, Miyakawa T, Ageta-Ishihara N, Kobayashi K, Kinoshita M, Kinoshita A. Mice with cleavage-resistant N-cadherin exhibit synapse anomaly in the hippocampus and outperformance in spatial learning tasks. Mol Brain 2021; 14:23. [PMID: 33494786 PMCID: PMC7831172 DOI: 10.1186/s13041-021-00738-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/16/2021] [Indexed: 11/30/2022] Open
Abstract
N-cadherin is a homophilic cell adhesion molecule that stabilizes excitatory synapses, by connecting pre- and post-synaptic termini. Upon NMDA receptor (NMDAR) activation by glutamate, membrane-proximal domains of N-cadherin are cleaved serially by a-disintegrin-and-metalloprotease 10 (ADAM10) and then presenilin 1(PS1, catalytic subunit of the γ-secretase complex). To assess the physiological significance of the initial N-cadherin cleavage, we engineer the mouse genome to create a knock-in allele with tandem missense mutations in the mouse N-cadherin/Cadherin-2 gene (Cdh2 R714G, I715D, or GD) that confers resistance on proteolysis by ADAM10 (GD mice). GD mice showed a better performance in the radial maze test, with significantly less revisiting errors after intervals of 30 and 300 s than WT, and a tendency for enhanced freezing in fear conditioning. Interestingly, GD mice reveal higher complexity in the tufts of thorny excrescence in the CA3 region of the hippocampus. Fine morphometry with serial section transmission electron microscopy (ssTEM) and three-dimensional (3D) reconstruction reveals significantly higher synaptic density, significantly smaller PSD area, and normal dendritic spine volume in GD mice. This knock-in mouse has provided in vivo evidence that ADAM10-mediated cleavage is a critical step in N-cadherin shedding and degradation and involved in the structure and function of glutamatergic synapses, which affect the memory function.
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Affiliation(s)
- M. Asada-Utsugi
- School of Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Neurology, Shiga University of Medical Science, Seta-Tsukinowa-Cho Otsu, Shiga, 520-2192 Japan
| | - K. Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - M. Kubota
- School of Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Y. Noda
- School of Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Y. Tashiro
- School of Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - T. M. Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - H. Yamakado
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - M. Urushitani
- Department of Neurology, Shiga University of Medical Science, Seta-Tsukinowa-Cho Otsu, Shiga, 520-2192 Japan
| | - R. Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - S. Hattori
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, 470-1192 Japan
| | - T. Miyakawa
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, 470-1192 Japan
| | - N. Ageta-Ishihara
- Division of Biological Sciences, Department of Molecular Biology, Nagoya University Graduate School of Science, Nagoya, 464-8602 Japan
| | - K. Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Tokyo, 113-8602 Japan
| | - M. Kinoshita
- Division of Biological Sciences, Department of Molecular Biology, Nagoya University Graduate School of Science, Nagoya, 464-8602 Japan
| | - A. Kinoshita
- School of Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Kobayashi K, Mikahara Y, Murata Y, Morita D, Matsuura S, Segi-Nishida E, Suzuki H. Predominant Role of Serotonin at the Hippocampal Mossy Fiber Synapse with Redundant Monoaminergic Modulation. iScience 2020; 23:101025. [PMID: 32283526 PMCID: PMC7155202 DOI: 10.1016/j.isci.2020.101025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/08/2020] [Accepted: 03/25/2020] [Indexed: 12/28/2022] Open
Abstract
The hippocampal mossy fiber (MF) synapse has been implicated in the pathophysiology and treatment of psychiatric disorders. Alterations of dopaminergic and serotonergic modulations at this synapse are candidate mechanisms underlying antidepressant and other related treatments. However, these monoaminergic modulations share the intracellular signaling pathway at the MF synapse, which implies redundancy in their functions. We here show that endogenous monoamines can potentiate MF synaptic transmission in mouse hippocampal slices by activating the serotonin 5-HT4 receptor. Dopamine receptors were not effectively activated by endogenous agonists, suggesting that the dopaminergic modulation is latent. Electroconvulsive treatment enhanced the 5-HT4 receptor-mediated serotonergic synaptic potentiation specifically at the MF synapse, increased the hippocampal serotonin content, and produced an anxiolytic-like behavioral effect in a 5-HT4 receptor-dependent manner. These results suggest that serotonin plays a predominant role in monoaminergic modulations at the MF synapse. Augmentation of this serotonergic modulation may mediate anxiolytic effects of electroconvulsive treatment.
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Affiliation(s)
- Katsunori Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan.
| | - Yasunori Mikahara
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Yuka Murata
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Daiki Morita
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Sumire Matsuura
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Eri Segi-Nishida
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
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Shuto T, Kuroiwa M, Sotogaku N, Kawahara Y, Oh YS, Jang JH, Shin CH, Ohnishi YN, Hanada Y, Miyakawa T, Kim Y, Greengard P, Nishi A. Obligatory roles of dopamine D1 receptors in the dentate gyrus in antidepressant actions of a selective serotonin reuptake inhibitor, fluoxetine. Mol Psychiatry 2020; 25:1229-1244. [PMID: 30531938 PMCID: PMC7244404 DOI: 10.1038/s41380-018-0316-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 10/10/2018] [Accepted: 11/12/2018] [Indexed: 12/28/2022]
Abstract
Depression is a leading cause of disability. Current pharmacological treatment of depression is insufficient, and development of improved treatments especially for treatment-resistant depression is desired. Understanding the neurobiology of antidepressant actions may lead to development of improved therapeutic approaches. Here, we demonstrate that dopamine D1 receptors in the dentate gyrus act as a pivotal mediator of antidepressant actions in mice. Chronic administration of a selective serotonin reuptake inhibitor (SSRI), fluoxetine, increases D1 receptor expression in mature granule cells in the dentate gyrus. The increased D1 receptor signaling, in turn, contributes to the actions of chronic fluoxetine treatment, such as suppression of acute stress-evoked serotonin release, stimulation of adult neurogenesis and behavioral improvement. Importantly, under severely stressed conditions, chronic administration of a D1 receptor agonist in conjunction with fluoxetine restores the efficacy of fluoxetine actions on D1 receptor expression and behavioral responses. Thus, our results suggest that stimulation of D1 receptors in the dentate gyrus is a potential adjunctive approach to improve therapeutic efficacy of SSRI antidepressants.
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Affiliation(s)
- Takahide Shuto
- 0000 0001 0706 0776grid.410781.bDepartment of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011 Japan
| | - Mahomi Kuroiwa
- 0000 0001 0706 0776grid.410781.bDepartment of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011 Japan
| | - Naoki Sotogaku
- 0000 0001 0706 0776grid.410781.bDepartment of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011 Japan
| | - Yukie Kawahara
- 0000 0001 0706 0776grid.410781.bDepartment of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011 Japan
| | - Yong-Seok Oh
- 0000 0001 2166 1519grid.134907.8Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065 USA ,0000 0004 0438 6721grid.417736.0Department of Brain-Cognitive Sciences, Daegu-Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpung-myeon, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Jin-Hyeok Jang
- 0000 0004 0438 6721grid.417736.0Department of Brain-Cognitive Sciences, Daegu-Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpung-myeon, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Chang-Hoon Shin
- 0000 0004 0438 6721grid.417736.0Department of Brain-Cognitive Sciences, Daegu-Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpung-myeon, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Yoshinori N. Ohnishi
- 0000 0001 0706 0776grid.410781.bDepartment of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011 Japan
| | - Yuuki Hanada
- 0000 0001 0706 0776grid.410781.bDepartment of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011 Japan
| | - Tsuyoshi Miyakawa
- 0000 0004 1761 798Xgrid.256115.4Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192 Japan
| | - Yong Kim
- 0000 0001 2166 1519grid.134907.8Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065 USA
| | - Paul Greengard
- 0000 0001 2166 1519grid.134907.8Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065 USA
| | - Akinori Nishi
- Department of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan. .,Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY, 10065, USA.
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Wang Z, Lin Y, Liu W, Kuang P, Lao W, Ji Y, Zhu H. Voltage-Gated Sodium Channels Are Involved in Cognitive Impairments in Parkinson's Disease- like Rats. Neuroscience 2019; 418:231-243. [DOI: 10.1016/j.neuroscience.2019.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/11/2019] [Accepted: 08/12/2019] [Indexed: 01/08/2023]
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Matheus Gauy M, Lengler J, Einarsson H, Meier F, Weissenberger F, Yanik MF, Steger A. A Hippocampal Model for Behavioral Time Acquisition and Fast Bidirectional Replay of Spatio-Temporal Memory Sequences. Front Neurosci 2018; 12:961. [PMID: 30618583 PMCID: PMC6306028 DOI: 10.3389/fnins.2018.00961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/03/2018] [Indexed: 01/09/2023] Open
Abstract
The hippocampus is known to play a crucial role in the formation of long-term memory. For this, fast replays of previously experienced activities during sleep or after reward experiences are believed to be crucial. But how such replays are generated is still completely unclear. In this paper we propose a possible mechanism for this: we present a model that can store experienced trajectories on a behavioral timescale after a single run, and can subsequently bidirectionally replay such trajectories, thereby omitting any specifics of the previous behavior like speed, etc, but allowing repetitions of events, even with different subsequent events. Our solution builds on well-known concepts, one-shot learning and synfire chains, enhancing them by additional mechanisms using global inhibition and disinhibition. For replays our approach relies on dendritic spikes and cholinergic modulation, as supported by experimental data. We also hypothesize a functional role of disinhibition as a pacemaker during behavioral time.
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Affiliation(s)
- Marcelo Matheus Gauy
- Department of Computer Science, Institute of Theoretical Computer Science, ETH Zurich, Zurich, Switzerland
| | - Johannes Lengler
- Department of Computer Science, Institute of Theoretical Computer Science, ETH Zurich, Zurich, Switzerland
| | - Hafsteinn Einarsson
- Department of Computer Science, Institute of Theoretical Computer Science, ETH Zurich, Zurich, Switzerland
| | - Florian Meier
- Department of Computer Science, Institute of Theoretical Computer Science, ETH Zurich, Zurich, Switzerland
| | - Felix Weissenberger
- Department of Computer Science, Institute of Theoretical Computer Science, ETH Zurich, Zurich, Switzerland
| | - Mehmet Fatih Yanik
- Department of Information Technology and Electrical Engineering, Institute for Neuroinformatics, ETH Zurich, Zurich, Switzerland
| | - Angelika Steger
- Department of Computer Science, Institute of Theoretical Computer Science, ETH Zurich, Zurich, Switzerland
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8
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Kobayashi K, Suzuki H. Synapse-selective rapid potentiation of hippocampal synaptic transmission by 7,8-dihydroxyflavone. Neuropsychopharmacol Rep 2018; 38:197-203. [PMID: 30280523 PMCID: PMC7292275 DOI: 10.1002/npr2.12033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 08/29/2018] [Accepted: 09/05/2018] [Indexed: 12/25/2022] Open
Abstract
AIM The identification of 7,8-dihydroxyflavone (DHF) as a small molecule agonist for tropomyosin-related kinase B (TrkB) facilitated understanding of the role of TrkB signaling in regulating higher brain functions. DHF can penetrate the blood-brain barrier after systemic administration and changes the performance of cognitive and emotional behavioral tasks. However, it is poorly understood how DHF modulates neuronal functions at cellular levels. Aiming to understand the cellular basis underlying DHF-induced modifications of the brain functions, we examined the effects of DHF on the hippocampal excitatory synaptic transmission. METHODS Field excitatory postsynaptic potentials were recorded using hippocampal slices prepared from adult male mice. Effects of bath-applied DHF on the synaptic efficacy were examined. RESULTS We found that DHF induced robust synaptic potentiation at the mossy fiber to CA3 synapse. DHF had minimal effects at other hippocampal excitatory synapses or at immature mossy fiber synapse in juvenile mice. The TrkB receptor blockers K252a and ANA-12 did not affect the DHF-induced synaptic potentiation. Drug screening revealed that relatively low concentrations of 2-aminoethoxydiphenylborane blocked the DHF-induced synaptic potentiation. CONCLUSION Our results demonstrate that DHF selectively potentiates hippocampal mossy fiber synaptic transmission via a TrkB receptor-independent mechanism. This novel neuromodulatory effect of DHF may influence higher brain functions by itself or together with the activation of the TrkB receptor. The rapid induction of the potentiation implies its potential importance in the acute behavioral effects of DHF.
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Affiliation(s)
- Katsunori Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
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9
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Leeboonngam T, Pramong R, Sae-Ung K, Govitrapong P, Phansuwan-Pujito P. Neuroprotective effects of melatonin on amphetamine-induced dopaminergic fiber degeneration in the hippocampus of postnatal rats. J Pineal Res 2018; 64. [PMID: 29149481 DOI: 10.1111/jpi.12456] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/10/2017] [Indexed: 12/21/2022]
Abstract
Chronic amphetamine (AMPH) abuse leads to damage of the hippocampus, the brain area associated with learning and memory process. Previous results have shown that AMPH-induced dopamine neurotransmitter release, reactive oxygen species formation, and degenerative protein aggregation lead to neuronal death. Melatonin, a powerful antioxidant, plays a role as a neuroprotective agent. The objective of this study was to investigate whether the protective effect of melatonin on AMPH-induced hippocampal damage in the postnatal rat acts through the dopaminergic pathway. Four-day-old postnatal rats were subcutaneously injected with 5-10 mg/kg AMPH and pretreated with 10 mg/kg melatonin prior to AMPH exposure for seven days. The results showed that melatonin decreased the AMPH-induced hippocampal neuronal degeneration in the dentate gyrus, CA1, and CA3. Melatonin attenuated the reduction in the expression of hippocampal synaptophysin, PSD-95, α-synuclein, and N-methyl-D-aspartate (NMDA) receptor protein and mRNA caused by AMPH. Melatonin attenuated the AMPH-induced reduction in dopamine transporter (DAT) protein expression in the hippocampus and the reduction in mRNA expression in the ventral tegmental area (VTA). Immunofluorescence demonstrated that melatonin not only prevented the AMPH-induced loss of DAT and NMDA receptor but also prevented AMPH-induced α-synuclein overexpression in the dentate gyrus, CA1, and CA3. Melatonin decreased the AMPH-induced reduction in the protein and mRNA of the NMDA receptor downstream signaling molecule, calcium/calmodulin-dependent protein kinase II (CaMKII), and the melatonin receptors (MT1 and MT2). This study showed that melatonin prevented AMPH-induced toxicity in the hippocampus of postnatal rats possibly via its antioxidative effect and mitochondrial protection.
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Affiliation(s)
- Tanawan Leeboonngam
- Department of Anatomy, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand
| | - Ratchadaporn Pramong
- Department of Anatomy, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand
| | - Kwankanit Sae-Ung
- Innovative Learning Center, Srinakharinwirot University, Bangkok, Thailand
| | - Piyarat Govitrapong
- Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakorn Pathom, Thailand
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Imoto Y, Segi-Nishida E, Suzuki H, Kobayashi K. Rapid and stable changes in maturation-related phenotypes of the adult hippocampal neurons by electroconvulsive treatment. Mol Brain 2017; 10:8. [PMID: 28253930 PMCID: PMC5335812 DOI: 10.1186/s13041-017-0288-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 02/22/2017] [Indexed: 12/28/2022] Open
Abstract
Electroconvulsive therapy (ECT) is a highly effective and fast-acting treatment for depression. Despite a long history of clinical use, its mechanism of action remains poorly understood. Recently, a novel cellular mechanism of antidepressant action has been proposed: the phenotype of mature brain neurons is transformed to immature-like one by antidepressant drug treatments. We show here that electroconvulsive stimulation (ECS), an animal model of ECT, causes profound changes in maturation-related phenotypes of neurons in the hippocampal dentate gyrus of adult mice. Single ECS immediately reduced expression of mature neuronal markers in almost entire population of dentate granule cells. After ECS treatments, granule cells showed some of physiological properties characteristic of immature granule cells such as higher somatic intrinsic excitability and smaller frequency facilitation at the detate-to-CA3 synapse. The rapid downregulation of maturation markers was suppressed by antagonizing glutamate NMDA receptors, but not by perturbing the serotonergic system. While single ECS caused short-lasting effects, repeated ECS induced stable changes in the maturation-related phenotypes lasting more than 2 weeks along with enhancement of synaptic excitation of granule cells. Augmentation of synaptic inhibition or blockade of NMDA receptors after repeated ECS facilitated regaining the initial mature phenotype, suggesting a role for endogenous neuronal excitation in maintaining the altered maturation-related phenotype probably via NMDA receptor activation. These results suggest that brief neuronal activation by ECS induces "dematuration" of the mature granule cells and that enhanced endogenous excitability is likely to support maintenance of such a demature state. The global increase in neuronal excitability accompanying this process may be relevant to the high efficacy of ECT.
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Affiliation(s)
- Yuki Imoto
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Eri Segi-Nishida
- Center for Integrative Education in Pharmacy and Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan. .,Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Katsushika-ku, Tokyo, Japan.
| | - Hidenori Suzuki
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Sendagi, Bunkyō, Tokyo, Japan.,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan
| | - Katsunori Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Sendagi, Bunkyō, Tokyo, Japan. .,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan.
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11
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Kobayashi K, Imoto Y, Yamamoto F, Kawasaki M, Ueno M, Segi-Nishida E, Suzuki H. Rapid and lasting enhancement of dopaminergic modulation at the hippocampal mossy fiber synapse by electroconvulsive treatment. J Neurophysiol 2016; 117:284-289. [PMID: 27784811 DOI: 10.1152/jn.00740.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/21/2016] [Indexed: 12/24/2022] Open
Abstract
Electroconvulsive therapy (ECT) is an established effective treatment for medication-resistant depression with the rapid onset of action. However, its cellular mechanism of action has not been revealed. We have previously shown that chronic antidepressant drug treatments enhance dopamine D1-like receptor-dependent synaptic potentiation at the hippocampal mossy fiber (MF)-CA3 excitatory synapse. In this study we show that ECT-like treatments in mice also have marked effects on the dopaminergic synaptic modulation. Repeated electroconvulsive stimulation (ECS), an animal model of ECT, strongly enhanced the dopamine-induced synaptic potentiation at the MF synapse in hippocampal slices. Significant enhancement was detectable after the second ECS, and further repetition of ECS up to 11 times monotonously increased the magnitude of enhancement. After repeated ECS, the dopamine-induced synaptic potentiation remained enhanced for more than 4 wk. These synaptic effects of ECS were accompanied by increased expression of the dopamine D1 receptor gene. Our results demonstrate that robust neuronal activation by ECS induces rapid and long-lasting enhancement of dopamine-induced synaptic potentiation at the MF synapse, likely via increased expression of the D1 receptor, at least in part. This rapid enhancement of dopamine-induced potentiation at the excitatory synapse may be relevant to the fast-acting antidepressant effect of ECT. NEW & NOTEWORTHY We show that electroconvulsive therapy (ECT)-like stimulation greatly enhances synaptic potentiation induced by dopamine at the excitatory synapse formed by the hippocampal mossy fiber in mice. The effect of ECT-like stimulation on the dopaminergic modulation was rapidly induced, maintained for more than 4 wk after repeated treatments, and most likely mediated by increased expression of the dopamine D1 receptor. These effects may be relevant to fast-acting strong antidepressant action of ECT.
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Affiliation(s)
- Katsunori Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan; .,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan
| | - Yuki Imoto
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Fumi Yamamoto
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Mayu Kawasaki
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Miyuki Ueno
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Eri Segi-Nishida
- Center for Integrative Education in Pharmacy and Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; and.,Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan
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12
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Prince LY, Bacon TJ, Tigaret CM, Mellor JR. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit. Front Synaptic Neurosci 2016; 8:32. [PMID: 27799909 PMCID: PMC5065980 DOI: 10.3389/fnsyn.2016.00032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/20/2016] [Indexed: 12/16/2022] Open
Abstract
The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval.
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Affiliation(s)
- Luke Y Prince
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Travis J Bacon
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Cezar M Tigaret
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Jack R Mellor
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
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Kobayashi K. Regulation of neuronal maturity and its functional meaning in the adult dentate gyrus. Nihon Yakurigaku Zasshi 2016; 148:176-179. [PMID: 27725564 DOI: 10.1254/fpj.148.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Hagena H, Manahan-Vaughan D. Dopamine D1/D5, But not D2/D3, Receptor Dependency of Synaptic Plasticity at Hippocampal Mossy Fiber Synapses that Is Enabled by Patterned Afferent Stimulation, or Spatial Learning. Front Synaptic Neurosci 2016; 8:31. [PMID: 27721791 PMCID: PMC5033958 DOI: 10.3389/fnsyn.2016.00031] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/08/2016] [Indexed: 01/11/2023] Open
Abstract
Although the mossy fiber (MF) synapses of the hippocampal CA3 region display quite distinct properties in terms of the molecular mechanisms that underlie synaptic plasticity, they nonetheless exhibit persistent (>24 h) synaptic plasticity that is akin to that observed at the Schaffer collateral (SCH)-CA1 and perforant path (PP)-dentate gyrus (DG) synapses of freely behaving rats. In addition, they also respond to novel spatial learning with very enduring forms of long-term potentiation (LTP) and long-term depression (LTD). These latter forms of synaptic plasticity are directly related to the learning behavior: novel exploration of generalized changes in space facilitates the expression of LTP at MF-CA3 synapses, whereas exploration of novel configurations of large environmental features facilitates the expression of LTD. In the absence of spatial novelty, synaptic plasticity is not expressed. Motivation is a potent determinant of whether learning about the spatial experience effectively occurs and the neuromodulator dopamine (DA) plays a key role in motivation-based learning. Prior research on the regulation by DA receptors of long-term synaptic plasticity in CA1 and DG synapses in vivo suggests that whereas D2/D3 receptors may modulate a general predisposition toward expressing plasticity, D1/D5 receptors may directly regulate the direction of change in synaptic strength that occurs during learning. Although the CA3 region is believed to play a pivotal role in many forms of learning, the role of dopamine receptors in persistent (>24 h) forms of synaptic plasticity at MF-CA3 synapses is unknown. Here, we report that whereas pharmacological antagonism of D2/D3 receptors had no impact on LTP or LTD, antagonism of D1/D5 receptors significantly impaired LTP and LTD that were induced by solely by means of patterned afferent stimulation, or LTP/LTD that are typically enhanced by the conjunction of afferent stimulation and novel spatial learning. These data indicate an important role for DA acting on D1/D5 receptors in the support of long-lasting and learning-related forms of synaptic plasticity at MF-CA3 synapses and provide further evidence for an important neuromodulatory role for this receptor in experience-dependent synaptic encoding in the hippocampal subfields.
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Affiliation(s)
- Hardy Hagena
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum Bochum, Germany
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15
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Effects of Repeated Low-Dose Exposure of the Nerve Agent VX on Monoamine Levels in Different Brain Structures in Mice. Neurochem Res 2014; 39:911-21. [DOI: 10.1007/s11064-014-1286-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 03/11/2014] [Accepted: 03/14/2014] [Indexed: 11/27/2022]
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16
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Calabresi P, Castrioto A, Di Filippo M, Picconi B. New experimental and clinical links between the hippocampus and the dopaminergic system in Parkinson's disease. Lancet Neurol 2013; 12:811-21. [DOI: 10.1016/s1474-4422(13)70118-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Kobayashi K, Ikeda Y, Asada M, Inagaki H, Kawada T, Suzuki H. Corticosterone facilitates fluoxetine-induced neuronal plasticity in the hippocampus. PLoS One 2013; 8:e63662. [PMID: 23675498 PMCID: PMC3651130 DOI: 10.1371/journal.pone.0063662] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 04/03/2013] [Indexed: 01/10/2023] Open
Abstract
The hippocampal dentate gyrus has been implicated in a neuronal basis of antidepressant action. We have recently shown a distinct form of neuronal plasticity induced by the serotonergic antidepressant fluoxetine, that is, a reversal of maturation of the dentate granule cells in adult mice. This “dematuration” is induced in a large population of dentate neurons and maintained for at least one month after withdrawal of fluoxetine, suggesting long-lasting strong influence of dematuration on brain functioning. However, reliable induction of dematuration required doses of fluoxetine higher than suggested optimal doses for mice (10 to 18 mg/kg/day), which casts doubt on the clinical relevance of this effect. Since our previous studies were performed in naive mice, in the present study, we reexamined effects of fluoxetine using mice treated with chronic corticosterone that model neuroendocrine pathophysiology associated with depression. In corticosterone-treated mice, fluoxetine at 10 mg/kg/day downregulated expression of mature granule cell markers and attenuated strong frequency facilitation at the synapse formed by the granule cell axon mossy fiber, suggesting the induction of granule cell dematuration. In addition, fluoxetine caused marked enhancement of dopaminergic modulation at the mossy fiber synapse. In vehicle-treated mice, however, fluoxetine at this dose had no significant effects. The plasma level of fluoxetine was comparable to that in patients taking chronic fluoxetine, and corticosterone did not affect it. These results indicate that corticosterone facilitates fluoxetine-induced plastic changes in the dentate granule cells. Our finding may provide insight into neuronal mechanisms underlying enhanced responsiveness to antidepressant medication in certain pathological conditions.
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Affiliation(s)
- Katsunori Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan.
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Sharopov S, Moser J, Chen R, Kolbaev SN, Bernedo VE, Werhahn KJ, Luhmann HJ, Kilb W. Dopaminergic modulation of low-Mg2+-induced epileptiform activity in the intact hippocampus of the newborn mouse in vitro. J Neurosci Res 2012; 90:2020-33. [DOI: 10.1002/jnr.23084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 04/11/2012] [Accepted: 04/13/2012] [Indexed: 11/12/2022]
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Kobayashi K, Haneda E, Higuchi M, Suhara T, Suzuki H. Chronic fluoxetine selectively upregulates dopamine D₁-like receptors in the hippocampus. Neuropsychopharmacology 2012; 37:1500-8. [PMID: 22278095 PMCID: PMC3327854 DOI: 10.1038/npp.2011.335] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The dentate gyrus of the hippocampus has been implicated in mechanisms of action of selective serotonin reuptake inhibitors (SSRIs). We have recently demonstrated that the SSRI fluoxetine can reverse the state of maturation of the adult dentate granule cells and enhances serotonin 5-HT₄ receptor-mediated synaptic potentiation at the synapses formed by their mossy fiber axons. Here, we show that fluoxetine can induce long-lasting enhancement of dopaminergic modulation at the mossy fiber synapse. Synaptic responses arising from the mossy fiber-CA3 pyramidal cell synapse were recorded using acute mouse hippocampal slices. Dopamine potentiates mossy fiber synaptic transmission by activating D₁-like receptors. Chronic fluoxetine treatment induced a prominent increase in the magnitude of dopamine-induced synaptic potentiation, and this effect was maintained at least up to 1 month after withdrawal of fluoxetine. Quantitative autoradiography revealed that binding of the D₁-like receptor ligand [³H]SCH23390 was selectively increased in the dentate gyrus and along the mossy fiber in fluoxetine-treated mice. However, binding of the 5-HT₄ receptor ligand [³H]GR113808 was not significantly changed. These results suggest that chronic fluoxetine enhanced the dopaminergic modulation at least in part by upregulating expression of D₁-like receptors, while the enhanced serotonergic modulation may be mediated by modifications of downstream signaling pathways. These enhanced monoaminergic modulations would greatly increase excitatory drive to the hippocampal circuit through the dentate gyrus. The highly localized upregulation of D₁-like receptors further supports the importance of the dentate gyrus in the mechanism of action of SSRIs.
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Affiliation(s)
- Katsunori Kobayashi
- Department of Pharmacology, Nippon Medical School, Sendagi, Bunkyo-ku, Tokyo, Japan.
| | - Eisuke Haneda
- Department of Pharmacology, Nippon Medical School, Sendagi, Bunkyo-ku, Tokyo, Japan
| | - Makoto Higuchi
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan
| | - Tetsuya Suhara
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Nippon Medical School, Sendagi, Bunkyo-ku, Tokyo, Japan,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan
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Vivar C, Traub RD, Gutiérrez R. Mixed electrical-chemical transmission between hippocampal mossy fibers and pyramidal cells. Eur J Neurosci 2011; 35:76-82. [PMID: 22151275 DOI: 10.1111/j.1460-9568.2011.07930.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Morphological and electrophysiological studies have shown that granule cell axons, the mossy fibers (MFs), establish gap junctions and therefore electrical communication among them. That granule cells express gap junctional proteins in their axons suggests the possibility that their terminals also express them. If this were to be the case, mixed electrical-chemical communication could be supported, as MF terminals normally use glutamate for fast communication with their target cells. Here we present electrophysiological studies in the rat and modeling studies consistent with this hypothesis. We show that MF activation produced fast spikelets followed by excitatory postsynaptic potentials in pyramidal cells (PCs), which, unlike the spikelets, underwent frequency potentiation and were strongly depressed by activation of metabotropic glutamate receptors, as expected from transmission of MF origin. The spikelets, which persisted during blockade of chemical transmission, were potentiated by dopamine and suppressed by the gap junction blocker carbenoxolone. The various waveforms evoked by MF stimulation were replicated in a multi-compartment model of a PC by brief current-pulse injections into the proximal apical dendritic compartment, where MFs are known to contact PCs. Mixed electrical and glutamatergic communication between granule cells and some PCs in CA3 may ensure the activation of sets of PCs, bypassing the strong action of concurrent feed-forward inhibition that granule cells activate. Importantly, MF-to-PC electrical coupling may allow bidirectional, possibly graded, communication that can be faster than chemical synapses and subject to different forms of modulation.
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Affiliation(s)
- Carmen Vivar
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, México, D.F., México
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Chu HY, Wu Q, Zhou S, Cao X, Zhang A, Jin GZ, Hu GY, Zhen X. SKF83959 suppresses excitatory synaptic transmission in rat hippocampus via a dopamine receptor-independent mechanism. J Neurosci Res 2011; 89:1259-66. [DOI: 10.1002/jnr.22653] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 01/24/2023]
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Kobayashi K, Umeda-Yano S, Yamamori H, Takeda M, Suzuki H, Hashimoto R. Correlated alterations in serotonergic and dopaminergic modulations at the hippocampal mossy fiber synapse in mice lacking dysbindin. PLoS One 2011; 6:e18113. [PMID: 21448290 PMCID: PMC3063243 DOI: 10.1371/journal.pone.0018113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 02/25/2011] [Indexed: 01/21/2023] Open
Abstract
Dysbindin-1 (dystrobrevin-binding protein 1, DTNBP1) is one of the promising schizophrenia susceptibility genes. Dysbindin protein is abundantly expressed in synaptic regions of the hippocampus, including the terminal field of the mossy fibers, and this hippocampal expression of dysbindin is strongly reduced in patients with schizophrenia. In the present study, we examined the functional role of dysbindin in hippocampal mossy fiber-CA3 synaptic transmission and its modulation using the sandy mouse, a spontaneous mutant with deletion in the dysbindin gene. Electrophysiological recordings were made in hippocampal slices prepared from adult male sandy mice and their wild-type littermates. Basic properties of the mossy fiber synaptic transmission in the mutant mice were generally normal except for slightly reduced frequency facilitation. Serotonin and dopamine, two major neuromodulators implicated in the pathophysiology of schizophrenia, can potentiate mossy fiber synaptic transmission probably via an increase in cAMP levels. Synaptic potentiation induced by serotonin and dopamine was very variable in magnitude in the mutant mice, with some mice showing prominent enhancement as compared with the wild-type mice. In addition, the magnitude of potentiation induced by these monoamines significantly correlated with each other in the mutant mice, indicating that a subpopulation of sandy mice has marked hypersensitivity to both serotonin and dopamine. While direct activation of the cAMP cascade by forskolin induced robust synaptic potentiation in both wild-type and mutant mice, this forskolin-induced potentaition correlated in magnitude with the serotonin-induced potentiation only in the mutant mice, suggesting a possible change in coupling of receptor activation to downstream signaling. These results suggest that the dysbindin deficiency could be an essential genetic factor that causes synaptic hypersensitivity to dopamine and serotonin. The altered monoaminergic modulation at the mossy fiber synapse could be a candidate pathophysiological basis for impairment of hippocampus-dependent brain functions in schizophrenia.
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Kobayashi K, Ikeda Y, Suzuki H. Behavioral destabilization induced by the selective serotonin reuptake inhibitor fluoxetine. Mol Brain 2011; 4:12. [PMID: 21410937 PMCID: PMC3065414 DOI: 10.1186/1756-6606-4-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 03/16/2011] [Indexed: 11/10/2022] Open
Abstract
Background Selective serotonin reuptake inhibitors (SSRIs) are widely used to treat mood and anxiety disorders. However, neuronal bases for both beneficial and adverse effects of SSRIs remain poorly understood. We have recently shown that the SSRI fluoxetine can reverse the state of maturation of hippocampal granule cells in adult mice. The granule cell "dematuration" is induced in a large population of granule cells, and greatly changes functional and physiological properties of these cells. Here we show that this unique form of neuronal plasticity is correlated with a distinct change in behavior of mice. Results We chronically treated adult male mice with fluoxetine, and examined its effect on several forms of behavior of mice. During fluoxetine treatments, mice showed a marked increase in day-to-day fluctuations of home cage activity levels that was characterized by occasional switching between hypoactivity and hyperactivity within a few days. This destabilized cage activity was accompanied by increased anxiety-related behaviors and could be observed up to 4 weeks after withdrawal from fluoxetine. As reported previously, the granule cell dematuration by fluoxetine includes a reduction of synaptic facilitation at the granule cell output, mossy fiber, synapse to the juvenile level. Mossy fiber synaptic facilitation examined electrophysiologically in acute hippocampal slices also remained suppressed after fluoxetine withdrawal and significantly correlated with the fluctuation of cage activity levels in individual mice. Furthermore, in mice lacking the 5-HT4 receptor, in which the granule cell dematuration has been shown to be attenuated, fluoxetine had no significant effect on the fluctuation of cage activity levels. Conclusions Our results demonstrate that the SSRI fluoxetine can induce marked day-to-day changes in activity levels of mice in the familiar environment, and that the dematuration of the hippocampal granule cells is closely associated with the expression of this destabilized behavior. Based on these results, we propose that the granule cell dematuration can be a potential cellular basis underlying switching-like changes in the behavioral state associated with SSRI treatments.
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Affiliation(s)
- Katsunori Kobayashi
- Department of Pharmacology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan.
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Chu HY, Yang Z, Zhao B, Jin GZ, Hu GY, Zhen X. Activation of phosphatidylinositol-linked D1-like receptors increases spontaneous glutamate release in rat somatosensory cortical neurons in vitro. Brain Res 2010; 1343:20-7. [DOI: 10.1016/j.brainres.2010.04.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Revised: 04/15/2010] [Accepted: 04/18/2010] [Indexed: 11/29/2022]
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Reversal of hippocampal neuronal maturation by serotonergic antidepressants. Proc Natl Acad Sci U S A 2010; 107:8434-9. [PMID: 20404165 DOI: 10.1073/pnas.0912690107] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Serotonergic antidepressant drugs have been commonly used to treat mood and anxiety disorders, and increasing evidence suggests potential use of these drugs beyond current antidepressant therapeutics. Facilitation of adult neurogenesis in the hippocampal dentate gyrus has been suggested to be a candidate mechanism of action of antidepressant drugs, but this mechanism may be only one of the broad effects of antidepressants. Here we show a distinct unique action of the serotonergic antidepressant fluoxetine in transforming the phenotype of mature dentate granule cells. Chronic treatments of adult mice with fluoxetine strongly reduced expression of the mature granule cell marker calbindin. The fluoxetine treatment induced active somatic membrane properties resembling immature granule cells and markedly reduced synaptic facilitation that characterizes the mature dentate-to-CA3 signal transmission. These changes cannot be explained simply by an increase in newly generated immature neurons, but best characterized as "dematuration" of mature granule cells. This granule cell dematuration developed along with increases in the efficacy of serotonin in 5-HT(4) receptor-dependent neuromodulation and was attenuated in mice lacking the 5-HT(4) receptor. Our results suggest that serotonergic antidepressants can reverse the established state of neuronal maturation in the adult hippocampus, and up-regulation of 5-HT(4) receptor-mediated signaling may play a critical role in this distinct action of antidepressants. Such reversal of neuronal maturation could affect proper functioning of the mature hippocampal circuit, but may also cause some beneficial effects by reinstating neuronal functions that are lost during development.
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Kobayashi K. Hippocampal Mossy Fiber Synaptic Transmission and Its Modulation. VITAMINS AND HORMONES 2010; 82:65-85. [DOI: 10.1016/s0083-6729(10)82004-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Sil’kis IG. Characteristics of the functioning of the hippocampal formation in waking and paradoxical sleep. ACTA ACUST UNITED AC 2009; 39:523-34. [DOI: 10.1007/s11055-009-9163-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 11/12/2007] [Indexed: 10/20/2022]
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Targeting the hippocampal mossy fiber synapse for the treatment of psychiatric disorders. Mol Neurobiol 2009; 39:24-36. [PMID: 19130314 DOI: 10.1007/s12035-008-8049-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 12/12/2008] [Indexed: 01/09/2023]
Abstract
It is widely known that new neurons are continuously generated in the dentate gyrus of the hippocampus in the adult mammalian brain. This neurogenesis has been implicated in depression and antidepressant treatments. Recent evidence also suggests that the dentate gyrus is involved in the neuropathology and pathophysiology of schizophrenia and other related psychiatric disorders. Especially, abnormal neuronal development in the dentate gyrus may be a plausible risk factor for the diseases. The synapse made by the mossy fiber, the output fiber of the dentate gyrus, plays a critical role in regulating neuronal activity in its target CA3 area. The mossy fiber synapse is characterized by remarkable activity-dependent short-term synaptic plasticity that is established during the postnatal development and is supposed to be central to the functional role of the mossy fiber. Any defects, including developmental abnormalities, in the dentate gyrus and drugs acting on the dentate gyrus can modulate the mossy fiber-CA3 synaptic transmission, which may eventually affect hippocampal functions. In this paper, I review recent evidence for involvement of the dentate gyrus and mossy fiber synapse in psychiatric disorders and discuss potential importance of drugs targeting the mossy fiber synapse either directly or indirectly in the therapeutic treatments of psychiatric disorders.
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Yamasaki N, Maekawa M, Kobayashi K, Kajii Y, Maeda J, Soma M, Takao K, Tanda K, Ohira K, Toyama K, Kanzaki K, Fukunaga K, Sudo Y, Ichinose H, Ikeda M, Iwata N, Ozaki N, Suzuki H, Higuchi M, Suhara T, Yuasa S, Miyakawa T. Alpha-CaMKII deficiency causes immature dentate gyrus, a novel candidate endophenotype of psychiatric disorders. Mol Brain 2008; 1:6. [PMID: 18803808 PMCID: PMC2562999 DOI: 10.1186/1756-6606-1-6] [Citation(s) in RCA: 228] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 09/10/2008] [Indexed: 01/01/2023] Open
Abstract
Elucidating the neural and genetic factors underlying psychiatric illness is hampered by current methods of clinical diagnosis. The identification and investigation of clinical endophenotypes may be one solution, but represents a considerable challenge in human subjects. Here we report that mice heterozygous for a null mutation of the alpha-isoform of calcium/calmodulin-dependent protein kinase II (alpha-CaMKII+/-) have profoundly dysregulated behaviours and impaired neuronal development in the dentate gyrus (DG). The behavioral abnormalities include a severe working memory deficit and an exaggerated infradian rhythm, which are similar to symptoms seen in schizophrenia, bipolar mood disorder and other psychiatric disorders. Transcriptome analysis of the hippocampus of these mutants revealed that the expression levels of more than 2000 genes were significantly changed. Strikingly, among the 20 most downregulated genes, 5 had highly selective expression in the DG. Whereas BrdU incorporated cells in the mutant mouse DG was increased by more than 50 percent, the number of mature neurons in the DG was dramatically decreased. Morphological and physiological features of the DG neurons in the mutants were strikingly similar to those of immature DG neurons in normal rodents. Moreover, c-Fos expression in the DG after electric footshock was almost completely and selectively abolished in the mutants. Statistical clustering of human post-mortem brains using 10 genes differentially-expressed in the mutant mice were used to classify individuals into two clusters, one of which contained 16 of 18 schizophrenic patients. Nearly half of the differentially-expressed probes in the schizophrenia-enriched cluster encoded genes that are involved in neurogenesis or in neuronal migration/maturation, including calbindin, a marker for mature DG neurons. Based on these results, we propose that an "immature DG" in adulthood might induce alterations in behavior and serve as a promising candidate endophenotype of schizophrenia and other human psychiatric disorders.
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Affiliation(s)
- Nobuyuki Yamasaki
- Frontier Technology Center, Kyoto University Graduate School of Medicine, Japan.
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Chronic fluoxetine bidirectionally modulates potentiating effects of serotonin on the hippocampal mossy fiber synaptic transmission. J Neurosci 2008; 28:6272-80. [PMID: 18550770 DOI: 10.1523/jneurosci.1656-08.2008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) have been used to treat various psychiatric disorders. Although the cellular mechanisms underlying amelioration of particular symptoms are mostly unknown, recent studies have shown critical importance of the dentate gyrus of the hippocampus in behavioral effects of SSRIs in rodents. Here, we show that serotonin potentiates synaptic transmission between mossy fibers, the sole output of the dentate granule cells, and CA3 pyramidal cells in mouse hippocampal slices. This potentiation is mediated by activation of 5-HT(4) receptors and intracellular cAMP elevation. A chronic treatment of mice with fluoxetine, a widely used SSRI, bidirectionally modulates the 5-HT-induced potentiation: Fluoxetine enhances the potentiation induced by lower concentrations of serotonin, while attenuates that by the higher concentration, which represents stabilization of synaptic 5-HT action. In contrast to the chronic treatment, an acute application of fluoxetine in slices induces a leftward shift in the dose-response curve of the 5-HT-induced potentiation. Thus, acute and chronic fluoxetine treatments have distinct effects on the serotonergic modulation of the mossy fiber synaptic transmission. Exposure of mice to novel environments induces increases in locomotor activity and hippocampal extracellular 5-HT levels. In mice chronically treated with fluoxetine, the novelty-induced hyperactivity is reduced without significant alterations in home cage activity and motor skills. Our results suggest that the chronic fluoxetine treatment can stabilize the serotonergic modulation of the central synaptic transmission, which may contribute to attenuation of hyperactive behaviors.
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