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Silvennoinen K, Säisänen L, Hyppönen J, Rissanen SM, Karjalainen PA, D'Ambrosio S, Jimenez‐Jimenez D, Zagaglia S, Rothwell JC, Balestrini S, Sisodiya SM, Julkunen P, Mervaala E, Kälviäinen R. Short- and long-interval intracortical inhibition in EPM1 is related to genotype. Epilepsia 2023; 64:208-217. [PMID: 36398398 PMCID: PMC10107775 DOI: 10.1111/epi.17466] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Progressive myoclonic epilepsy type 1 (EPM1) is caused by biallelic alterations in the CSTB gene, most commonly dodecamer repeat expansions. Although transcranial magnetic stimulation (TMS)-induced long-interval intracortical inhibition (LICI) was previously reported to be normal in EPM1, short-interval intracortical inhibition (SICI) was reduced. We explored the association between these measures and the clinical and genetic features in a separate group of patients with EPM1. METHODS TMS combined with electromyography was performed under neuronavigation. LICI was induced with an inter-stimulus interval (ISI) of 100 ms, and SICI with ISIs of 2 and 3 ms, and their means (mSICIs) were expressed as the ratio of conditioned to unconditioned stimuli. LICI and mSICI were compared between patients and controls. Nonparametric correlation was used to study the association between inhibition and parameters of clinical severity, including the Unified Myoclonus Rating Scale (UMRS); among patients with EPM1 due to biallelic expansion repeats, also the association with the number of repeats was assessed. RESULTS The study protocol was completed in 19 patients (15 with biallelic expansion repeats and 4 compound heterozygotes), and 7 healthy, age- and sex-matched control participants. Compared to controls, patients demonstrated significantly less SICI (median mSICI ratio 1.18 vs 0.38; p < .001). Neither LICI nor SICI was associated with parameters of clinical severity. In participants with biallelic repeat expansions, the number of repeats in the more affected allele (greater repeat number [GRN]) correlated with LICI (rho = 0.872; p < .001) and SICI (rho = 0.689; p = .006). SIGNIFICANCE Our results strengthen the finding of deranged γ-aminobutyric acid (GABA)ergic inhibition in EPM1. LICI and SICI may have use as markers of GABAergic impairment in future trials of disease-modifying treatment in this condition. Whether a higher number of expansion repeats leads to greater GABAergic impairment warrants further study.
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Affiliation(s)
- Katri Silvennoinen
- Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyUK
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Department of Applied PhysicsUniversity of Eastern FinlandKuopioFinland
| | - Jelena Hyppönen
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
| | - Saara M. Rissanen
- Department of Applied PhysicsUniversity of Eastern FinlandKuopioFinland
| | | | - Sasha D'Ambrosio
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Dipartimento di Scienze Biomediche e Cliniche "L. Sacco"Università degli Studi di MilanoMilanItaly
| | - Diego Jimenez‐Jimenez
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - Sara Zagaglia
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - John C. Rothwell
- Sobell Department of Motor Neuroscience and Movement DisordersUCL Queen Square Institute of NeurologyLondonUK
| | - Simona Balestrini
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyUK
- Neuroscience DepartmentMember of ERN EpiCARE, Meyer Children HospitalFlorenceItaly
| | - Sanjay M. Sisodiya
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyUK
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Department of Applied PhysicsUniversity of Eastern FinlandKuopioFinland
| | - Esa Mervaala
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Institute of Clinical Medicine, School of Medicine, Faculty of Health SciencesUniversity of Eastern FinlandKuopioFinland
| | - Reetta Kälviäinen
- Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Institute of Clinical Medicine, School of Medicine, Faculty of Health SciencesUniversity of Eastern FinlandKuopioFinland
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Kim J, Kim S, Kim H, Hwang IW, Bae S, Karki S, Kim D, Ogelman R, Bang G, Kim JY, Kajander T, Um JW, Oh WC, Ko J. MDGA1 negatively regulates amyloid precursor protein-mediated synapse inhibition in the hippocampus. Proc Natl Acad Sci U S A 2022. [PMID: 35074912 DOI: 10.1073/pnas.2115326119/suppl_file/pnas.2115326119.sd01.xlsx] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023] Open
Abstract
Balanced synaptic inhibition, controlled by multiple synaptic adhesion proteins, is critical for proper brain function. MDGA1 (meprin, A-5 protein, and receptor protein-tyrosine phosphatase mu [MAM] domain-containing glycosylphosphatidylinositol anchor protein 1) suppresses synaptic inhibition in mammalian neurons, yet the molecular mechanisms underlying MDGA1-mediated negative regulation of GABAergic synapses remain unresolved. Here, we show that the MDGA1 MAM domain directly interacts with the extension domain of amyloid precursor protein (APP). Strikingly, MDGA1-mediated synaptic disinhibition requires the MDGA1 MAM domain and is prominent at distal dendrites of hippocampal CA1 pyramidal neurons. Down-regulation of APP in presynaptic GABAergic interneurons specifically suppressed GABAergic, but not glutamatergic, synaptic transmission strength and inputs onto both the somatic and dendritic compartments of hippocampal CA1 pyramidal neurons. Moreover, APP deletion manifested differential effects in somatostatin- and parvalbumin-positive interneurons in the hippocampal CA1, resulting in distinct alterations in inhibitory synapse numbers, transmission, and excitability. The infusion of MDGA1 MAM protein mimicked postsynaptic MDGA1 gain-of-function phenotypes that involve the presence of presynaptic APP. The overexpression of MDGA1 wild type or MAM, but not MAM-deleted MDGA1, in the hippocampal CA1 impaired novel object-recognition memory in mice. Thus, our results establish unique roles of APP-MDGA1 complexes in hippocampal neural circuits, providing unprecedented insight into trans-synaptic mechanisms underlying differential tuning of neuronal compartment-specific synaptic inhibition.
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Affiliation(s)
- Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Seungjoon Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Hyeonho Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - In-Wook Hwang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Sungwon Bae
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Sudeep Karki
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Dongwook Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Roberto Ogelman
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Geul Bang
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang 305-732, Korea
| | - Jin Young Kim
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang 305-732, Korea
| | - Tommi Kajander
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Won Chan Oh
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045;
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea;
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Navarro-Gonzalez C, Carceller H, Benito Vicente M, Serra I, Navarrete M, Domínguez-Canterla Y, Rodríguez-Prieto Á, González-Manteiga A, Fazzari P. Nrg1 haploinsufficiency alters inhibitory cortical circuits. Neurobiol Dis 2021; 157:105442. [PMID: 34246770 DOI: 10.1016/j.nbd.2021.105442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 05/19/2021] [Accepted: 06/30/2021] [Indexed: 11/19/2022] Open
Abstract
Neuregulin 1 (NRG1) and its receptor ERBB4 are schizophrenia (SZ) risk genes that control the development of both excitatory and inhibitory cortical circuits. Most studies focused on the characterization ErbB4 deficient mice. However, ErbB4 deletion concurrently perturbs the signaling of Nrg1 and Neuregulin 3 (Nrg3), another ligand expressed in the cortex. In addition, NRG1 polymorphisms linked to SZ locate mainly in non-coding regions and they may partially reduce Nrg1 expression. Here, to study the relevance of Nrg1 partial loss-of-function in cortical circuits we characterized a recently developed haploinsufficient mouse model of Nrg1 (Nrg1tm1Lex). These mice display SZ-like behavioral deficits. The cellular and molecular underpinnings of the behavioral deficits in Nrg1tm1Lex mice remain to be established. With multiple approaches including Magnetic Resonance Spectroscopy (MRS), electrophysiology, quantitative imaging and molecular analysis we found that Nrg1 haploinsufficiency impairs the inhibitory cortical circuits. We observed changes in the expression of molecules involved in GABAergic neurotransmission, decreased density of Vglut1 excitatory buttons onto Parvalbumin interneurons and decreased frequency of spontaneous inhibitory postsynaptic currents. Moreover, we found a decreased number of Parvalbumin positive interneurons in the cortex and altered expression of Calretinin. Interestingly, we failed to detect other alterations in excitatory neurons that were previously reported in ErbB4 null mice suggesting that the Nrg1 haploinsufficiency does not entirely phenocopies ErbB4 deletions. Altogether, this study suggests that Nrg1 haploinsufficiency primarily affects the cortical inhibitory circuits in the cortex and provides new insights into the structural and molecular synaptic impairment caused by NRG1 hypofunction in a preclinical model of SZ.
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Affiliation(s)
- Carmen Navarro-Gonzalez
- Lab of Cortical Circuits in Health and Disease, CIPF Centro de Investigación Príncipe Felipe, Valencia, Spain.
| | - Héctor Carceller
- Lab of Cortical Circuits in Health and Disease, CIPF Centro de Investigación Príncipe Felipe, Valencia, Spain.
| | - Marina Benito Vicente
- Laboratorio Resonancia Magnética de Investigación, Hospital Nacional de Parapléjicos, Toledo, Spain.
| | - Irene Serra
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain.
| | - Marta Navarrete
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain.
| | - Yaiza Domínguez-Canterla
- Lab of Cortical Circuits in Health and Disease, CIPF Centro de Investigación Príncipe Felipe, Valencia, Spain.
| | - Ángela Rodríguez-Prieto
- Lab of Cortical Circuits in Health and Disease, CIPF Centro de Investigación Príncipe Felipe, Valencia, Spain.
| | - Ana González-Manteiga
- Lab of Cortical Circuits in Health and Disease, CIPF Centro de Investigación Príncipe Felipe, Valencia, Spain.
| | - Pietro Fazzari
- Lab of Cortical Circuits in Health and Disease, CIPF Centro de Investigación Príncipe Felipe, Valencia, Spain; Consejo Superior de Investigaciones Científicas (CSIC), Centro de Biología Molecular Severo Ochoa, Madrid, Spain.
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Wiera G, Lebida K, Lech AM, Brzdąk P, Van Hove I, De Groef L, Moons L, Petrini EM, Barberis A, Mozrzymas JW. Long-term plasticity of inhibitory synapses in the hippocampus and spatial learning depends on matrix metalloproteinase 3. Cell Mol Life Sci 2021; 78:2279-2298. [PMID: 32959071 PMCID: PMC7966195 DOI: 10.1007/s00018-020-03640-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/19/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
Learning and memory are known to depend on synaptic plasticity. Whereas the involvement of plastic changes at excitatory synapses is well established, plasticity mechanisms at inhibitory synapses only start to be discovered. Extracellular proteolysis is known to be a key factor in glutamatergic plasticity but nothing is known about its role at GABAergic synapses. We reveal that pharmacological inhibition of MMP3 activity or genetic knockout of the Mmp3 gene abolishes induction of postsynaptic iLTP. Moreover, the application of exogenous active MMP3 mimics major iLTP manifestations: increased mIPSCs amplitude, enlargement of synaptic gephyrin clusters, and a decrease in the diffusion coefficient of synaptic GABAA receptors that favors their entrapment within the synapse. Finally, we found that MMP3 deficient mice show faster spatial learning in Morris water maze and enhanced contextual fear conditioning. We conclude that MMP3 plays a key role in iLTP mechanisms and in the behaviors that presumably in part depend on GABAergic plasticity.
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Affiliation(s)
- Grzegorz Wiera
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, 50-367, Wroclaw, Poland.
| | - Katarzyna Lebida
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, 50-367, Wroclaw, Poland.
| | - Anna Maria Lech
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, 50-367, Wroclaw, Poland
- Laboratory of Cellular Neurobiology, Department of Physiology and Molecular Neurobiology, Wroclaw University, 50-205, Wroclaw, Poland
| | - Patrycja Brzdąk
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, 50-367, Wroclaw, Poland
- Laboratory of Cellular Neurobiology, Department of Physiology and Molecular Neurobiology, Wroclaw University, 50-205, Wroclaw, Poland
| | - Inge Van Hove
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), 3000, Leuven, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), 3000, Leuven, Belgium
- Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), 3000, Leuven, Belgium
- Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Enrica Maria Petrini
- Laboratory of Synaptic Plasticity of Inhibitory Networks, Fondazione Istituto Italiano Di Tecnologia, 16163, Genoa, Italy
| | - Andrea Barberis
- Laboratory of Synaptic Plasticity of Inhibitory Networks, Fondazione Istituto Italiano Di Tecnologia, 16163, Genoa, Italy
| | - Jerzy W Mozrzymas
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, 50-367, Wroclaw, Poland
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Branchereau P, Martin E, Allain AE, Cazenave W, Supiot L, Hodeib F, Laupénie A, Dalvi U, Zhu H, Cattaert D. Relaxation of synaptic inhibitory events as a compensatory mechanism in fetal SOD spinal motor networks. eLife 2019; 8:e51402. [PMID: 31868588 PMCID: PMC6974356 DOI: 10.7554/elife.51402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/20/2019] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease affecting motor neurons (MNs) during late adulthood. Here, with the aim of identifying early changes underpinning ALS neurodegeneration, we analyzed the GABAergic/glycinergic inputs to E17.5 fetal MNs from SOD1G93A (SOD) mice in parallel with chloride homeostasis. Our results show that IPSCs are less frequent in SOD animals in accordance with a reduction of synaptic VIAAT-positive terminals. SOD MNs exhibited an EGABAAR10 mV more depolarized than in WT MNs associated with a KCC2 reduction. Interestingly, SOD GABAergic/glycinergic IPSCs and evoked GABAAR-currents exhibited a slower decay correlated to elevated [Cl-]i. Computer simulations revealed that a slower relaxation of synaptic inhibitory events acts as compensatory mechanism to strengthen GABA/glycine inhibition when EGABAAR is more depolarized. How such mechanisms evolve during pathophysiological processes remain to be determined, but our data indicate that at least SOD1 familial ALS may be considered as a neurodevelopmental disease.
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Affiliation(s)
| | - Elodie Martin
- University of BordeauxCNRS, INCIA, UMR 5287BordeauxFrance
| | | | | | - Laura Supiot
- University of BordeauxCNRS, INCIA, UMR 5287BordeauxFrance
| | - Fara Hodeib
- University of BordeauxCNRS, INCIA, UMR 5287BordeauxFrance
| | | | - Urvashi Dalvi
- University of BordeauxCNRS, INCIA, UMR 5287BordeauxFrance
| | - Hongmei Zhu
- University of BordeauxCNRS, INCIA, UMR 5287BordeauxFrance
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6
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Vascak M, Jin X, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Induces Structural and Functional Disconnection of Local Neocortical Inhibitory Networks via Parvalbumin Interneuron Diffuse Axonal Injury. Cereb Cortex 2018; 28:1625-1644. [PMID: 28334184 PMCID: PMC5907353 DOI: 10.1093/cercor/bhx058] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/20/2017] [Indexed: 12/18/2022] Open
Abstract
Diffuse axonal injury (DAI) plays a major role in cortical network dysfunction posited to cause excitatory/inhibitory imbalance after mild traumatic brain injury (mTBI). Current thought holds that white matter (WM) is uniquely vulnerable to DAI. However, clinically diagnosed mTBI is not always associated with WM DAI. This suggests an undetected neocortical pathophysiology, implicating GABAergic interneurons. To evaluate this possibility, we used mild central fluid percussion injury to generate DAI in mice with Cre-driven tdTomato labeling of parvalbumin (PV) interneurons. We followed tdTomato+ profiles using confocal and electron microscopy, together with patch-clamp analysis to probe for DAI-mediated neocortical GABAergic interneuron disruption. Within 3 h post-mTBI tdTomato+ perisomatic axonal injury (PSAI) was found across somatosensory layers 2-6. The DAI marker amyloid precursor protein colocalized with GAD67 immunoreactivity within tdTomato+ PSAI, representing the majority of GABAergic interneuron DAI. At 24 h post-mTBI, we used phospho-c-Jun, a surrogate DAI marker, for retrograde assessments of sustaining somas. Via this approach, we estimated DAI occurs in ~9% of total tdTomato+ interneurons, representing ~14% of pan-neuronal DAI. Patch-clamp recordings of tdTomato+ interneurons revealed decreased inhibitory transmission. Overall, these data show that PV interneuron DAI is a consistent and significant feature of experimental mTBI with important implications for cortical network dysfunction.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - Xiaotao Jin
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
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Kaneko R, Takatsuru Y, Morita A, Amano I, Haijima A, Imayoshi I, Tamamaki N, Koibuchi N, Watanabe M, Yanagawa Y. Inhibitory neuron-specific Cre-dependent red fluorescent labeling using VGAT BAC-based transgenic mouse lines with identified transgene integration sites. J Comp Neurol 2018; 526:373-396. [PMID: 29063602 DOI: 10.1002/cne.24343] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/30/2017] [Accepted: 10/17/2017] [Indexed: 01/15/2023]
Abstract
Inhibitory neurons are crucial for shaping and regulating the dynamics of the entire network, and disturbances in these neurons contribute to brain disorders. Despite the recent progress in genetic labeling techniques, the heterogeneity of inhibitory neurons requires the development of highly characterized tools that allow accurate, convenient, and versatile visualization of inhibitory neurons in the mouse brain. Here, we report a novel genetic technique to visualize the vast majority and/or sparse subsets of inhibitory neurons in the mouse brain without using techniques that require advanced skills. We developed several lines of Cre-dependent tdTomato reporter mice based on the vesicular GABA transporter (VGAT)-BAC, named VGAT-stop-tdTomato mice. The most useful line (line #54) was selected for further analysis based on two characteristics: the inhibitory neuron-specificity of tdTomato expression and the transgene integration site, which confers efficient breeding and fewer adverse effects resulting from transgene integration-related genomic disruption. Robust and inhibitory neuron-specific expression of tdTomato was observed in a wide range of developmental and cellular contexts. By breeding the VGAT-stop-tdTomato mouse (line #54) with a novel Cre driver mouse line, Galntl4-CreER, sparse labeling of inhibitory neurons was achieved following tamoxifen administration. Furthermore, another interesting line (line #58) was generated through the unexpected integration of the transgene into the X-chromosome and will be used to map X-chromosome inactivation of inhibitory neurons. Taken together, our studies provide new, well-characterized tools with which multiple aspects of inhibitory neurons can be studied in the mouse.
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Affiliation(s)
- Ryosuke Kaneko
- Bioresource Center, Gunma University Graduate School of Medicine, Gunma, Japan
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Yusuke Takatsuru
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Gunma, Japan
- Department of Medicine, Johmoh Hospital, Gunma, Japan
| | - Ayako Morita
- Bioresource Center, Gunma University Graduate School of Medicine, Gunma, Japan
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Izuki Amano
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Asahi Haijima
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Itaru Imayoshi
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Nobuaki Tamamaki
- Department of Morphological Neural Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Noriyuki Koibuchi
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Gunma, Japan
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Koch SC, Del Barrio MG, Dalet A, Gatto G, Günther T, Zhang J, Seidler B, Saur D, Schüle R, Goulding M. RORβ Spinal Interneurons Gate Sensory Transmission during Locomotion to Secure a Fluid Walking Gait. Neuron 2017; 96:1419-1431.e5. [PMID: 29224725 PMCID: PMC5828033 DOI: 10.1016/j.neuron.2017.11.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/27/2017] [Accepted: 11/08/2017] [Indexed: 01/17/2023]
Abstract
Animals depend on sensory feedback from mechanosensory afferents for the dynamic control of movement. This sensory feedback needs to be selectively modulated in a task- and context-dependent manner. Here, we show that inhibitory interneurons (INs) expressing the RORβ orphan nuclear receptor gate sensory feedback to the spinal motor system during walking and are required for the production of a fluid locomotor rhythm. Genetic manipulations that abrogate inhibitory RORβ IN function result in an ataxic gait characterized by exaggerated flexion movements and marked alterations to the step cycle. Inactivation of RORβ in inhibitory neurons leads to reduced presynaptic inhibition and changes to sensory-evoked reflexes, arguing that the RORβ inhibitory INs function to suppress the sensory transmission pathways that activate flexor motor reflexes and interfere with the ongoing locomotor program. VIDEO ABSTRACT.
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Affiliation(s)
- Stephanie C Koch
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Marta Garcia Del Barrio
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Antoine Dalet
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Graziana Gatto
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Thomas Günther
- Urologische Klinik und Zentrale Klinische Forschung, Klinikum der Universität Freiburg, Breisacherstrasse 66, 79106 Freiburg, Germany
| | - Jingming Zhang
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Barbara Seidler
- Department of Medicine II, School of Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaningerstr. 22, 81675 München, Germany
| | - Dieter Saur
- Department of Medicine II, School of Medicine, Klinikum rechts der Isar, Technische Universität München, Ismaningerstr. 22, 81675 München, Germany; Division of Translational Cancer Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Roland Schüle
- Urologische Klinik und Zentrale Klinische Forschung, Klinikum der Universität Freiburg, Breisacherstrasse 66, 79106 Freiburg, Germany
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Buhusi M, Obray D, Guercio B, Bartlett MJ, Buhusi CV. Chronic mild stress impairs latent inhibition and induces region-specific neural activation in CHL1-deficient mice, a mouse model of schizophrenia. Behav Brain Res 2017. [PMID: 28647594 DOI: 10.1016/j.bbr.2017.06.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Schizophrenia is a neurodevelopmental disorder characterized by abnormal processing of information and attentional deficits. Schizophrenia has a high genetic component but is precipitated by environmental factors, as proposed by the 'two-hit' theory of schizophrenia. Here we compared latent inhibition as a measure of learning and attention, in CHL1-deficient mice, an animal model of schizophrenia, and their wild-type littermates, under no-stress and chronic mild stress conditions. All unstressed mice as well as the stressed wild-type mice showed latent inhibition. In contrast, CHL1-deficient mice did not show latent inhibition after exposure to chronic stress. Differences in neuronal activation (c-Fos-positive cell counts) were noted in brain regions associated with latent inhibition: Neuronal activation in the prelimbic/infralimbic cortices and the nucleus accumbens shell was affected solely by stress. Neuronal activation in basolateral amygdala and ventral hippocampus was affected independently by stress and genotype. Most importantly, neural activation in nucleus accumbens core was affected by the interaction between stress and genotype. These results provide strong support for a 'two-hit' (genes x environment) effect on latent inhibition in CHL1-deficient mice, and identify CHL1-deficient mice as a model of schizophrenia-like learning and attention impairments.
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Affiliation(s)
- Mona Buhusi
- Interdisciplinary Program in Neuroscience, USTAR BioInnovations Center, Dept. Psychology, Utah State University, Logan UT, United States.
| | - Daniel Obray
- Interdisciplinary Program in Neuroscience, USTAR BioInnovations Center, Dept. Psychology, Utah State University, Logan UT, United States
| | - Bret Guercio
- Interdisciplinary Program in Neuroscience, USTAR BioInnovations Center, Dept. Psychology, Utah State University, Logan UT, United States
| | - Mitchell J Bartlett
- Interdisciplinary Program in Neuroscience, USTAR BioInnovations Center, Dept. Psychology, Utah State University, Logan UT, United States
| | - Catalin V Buhusi
- Interdisciplinary Program in Neuroscience, USTAR BioInnovations Center, Dept. Psychology, Utah State University, Logan UT, United States
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10
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Tong X, Peng Z, Zhang N, Cetina Y, Huang CS, Wallner M, Otis TS, Houser CR. Ectopic Expression of α6 and δ GABAA Receptor Subunits in Hilar Somatostatin Neurons Increases Tonic Inhibition and Alters Network Activity in the Dentate Gyrus. J Neurosci 2015; 35:16142-58. [PMID: 26658866 PMCID: PMC4682781 DOI: 10.1523/jneurosci.2853-15.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/23/2015] [Accepted: 11/01/2015] [Indexed: 11/21/2022] Open
Abstract
The role of GABAA receptor (GABAAR)-mediated tonic inhibition in interneurons remains unclear and may vary among subgroups. Somatostatin (SOM) interneurons in the hilus of the dentate gyrus show negligible expression of nonsynaptic GABAAR subunits and very low tonic inhibition. To determine the effects of ectopic expression of tonic GABAAR subtypes in these neurons, Cre-dependent viral vectors were used to express GFP-tagged GABAAR subunits (α6 and δ) selectively in hilar SOM neurons in SOM-Cre mice. In single-transfected animals, immunohistochemistry demonstrated strong expression of either the α6 or δ subunit; in cotransfected animals, both subunits were consistently expressed in the same neurons. Electrophysiology revealed a robust increase of tonic current, with progressively larger increases following transfection of δ, α6, and α6/δ subunits, respectively, indicating formation of functional receptors in all conditions and likely coassembly of the subunits in the same receptor following cotransfection. An in vitro model of repetitive bursting was used to determine the effects of increased tonic inhibition in hilar SOM interneurons on circuit activity in the dentate gyrus. Upon cotransfection, the frequency of GABAAR-mediated bursting in granule cells was reduced, consistent with a reduction in synchronous firing among hilar SOM interneurons. Moreover, in vivo studies of Fos expression demonstrated reduced activation of α6/δ-cotransfected neurons following acute seizure induction by pentylenetetrazole. The findings demonstrate that increasing tonic inhibition in hilar SOM interneurons can alter dentate gyrus circuit activity during strong stimulation and suggest that tonic inhibition of interneurons could play a role in regulating excessive synchrony within the network. SIGNIFICANCE STATEMENT In contrast to many hippocampal interneurons, somatostatin (SOM) neurons in the hilus of the dentate gyrus have very low levels of nonsynaptic GABAARs and exhibit very little tonic inhibition. In an effort to increase tonic inhibition selectively in these interneurons, we used Cre-dependent viral vectors in SOM-Cre mice to achieve interneuron-specific expression of the nonsynaptic GABAAR subunits (α6 and δ) in vivo. We show, for the first time, that such recombinant GFP-tagged GABAAR subunits are expressed robustly, assemble to form functional receptors, substantially increase tonic inhibition in SOM interneurons, and alter circuit activity within the dentate gyrus.
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Affiliation(s)
- Xiaoping Tong
- Departments of Neurobiology and Department of Anatomy, Histology and Embryology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China, and
| | | | | | | | | | - Martin Wallner
- Molecular and Medical Pharmacology and Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Thomas S Otis
- Departments of Neurobiology and Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095, Roche Pharmaceutical Research and Early Development, Neuroscience, Ophthalmology, and Rare Diseases Translational Area, Roche Innovation Center Basel, CH-4070, Basel, Switzerland
| | - Carolyn R Houser
- Departments of Neurobiology and Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095,
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11
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Stödberg T, McTague A, Ruiz AJ, Hirata H, Zhen J, Long P, Farabella I, Meyer E, Kawahara A, Vassallo G, Stivaros SM, Bjursell MK, Stranneheim H, Tigerschiöld S, Persson B, Bangash I, Das K, Hughes D, Lesko N, Lundeberg J, Scott RC, Poduri A, Scheffer IE, Smith H, Gissen P, Schorge S, Reith MEA, Topf M, Kullmann DM, Harvey RJ, Wedell A, Kurian MA. Mutations in SLC12A5 in epilepsy of infancy with migrating focal seizures. Nat Commun 2015; 6:8038. [PMID: 26333769 PMCID: PMC4569694 DOI: 10.1038/ncomms9038] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 07/10/2015] [Indexed: 12/30/2022] Open
Abstract
The potassium-chloride co-transporter KCC2, encoded by SLC12A5, plays a fundamental role in fast synaptic inhibition by maintaining a hyperpolarizing gradient for chloride ions. KCC2 dysfunction has been implicated in human epilepsy, but to date, no monogenic KCC2-related epilepsy disorders have been described. Here we show recessive loss-of-function SLC12A5 mutations in patients with a severe infantile-onset pharmacoresistant epilepsy syndrome, epilepsy of infancy with migrating focal seizures (EIMFS). Decreased KCC2 surface expression, reduced protein glycosylation and impaired chloride extrusion contribute to loss of KCC2 activity, thereby impairing normal synaptic inhibition and promoting neuronal excitability in this early-onset epileptic encephalopathy.
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Affiliation(s)
- Tommy Stödberg
- Department of Women's and Children's Health, Karolinska Institutet, SE-171 76 Stockholm, Sweden
- Neuropediatric Unit, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Amy McTague
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Institute of Child Health, London WC1N 1EH, UK
- Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Arnaud J. Ruiz
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK
| | - Hiromi Hirata
- Department of Chemistry and Biological Science, Graduate School of Science and Engineering, Aoyama Gakuin University, Sagamihara 252-5258 Kanagawa, Japan
- Center for Frontier Research, National Institute of Genetics, Yata 1111, Mishima, 411-8540 Shizuoka, Japan
- PREST, Japan Science and Technology Agency, Tokyo 102-0076, Japan
| | - Juan Zhen
- Department of Psychiatry, New York University School of Medicine, New York, New York 10016, USA
| | - Philip Long
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK
| | - Irene Farabella
- Institute of Structural and Molecular Biology, Crystallography/Department of Biological Sciences, Birkbeck College, University of London, WC1E 7HX, UK
| | - Esther Meyer
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Atsuo Kawahara
- Laboratory for Developmental Biology, Graduate School of Medical Science, University of Yamanashi, Chuo, 409-3898, Japan
| | - Grace Vassallo
- Department of Neurology, Royal Manchester Children's Hospital, Manchester, M13 9WL, UK
| | - Stavros M. Stivaros
- Academic Department of Radiology, Royal Manchester Children's Hospital, Manchester, M13 9WL, UK
- Imaging Science, School of Population Health, University of Manchester, Manchester, M13 9PL, UK
| | - Magnus K. Bjursell
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Center for Molecular Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Henrik Stranneheim
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Center for Molecular Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Stephanie Tigerschiöld
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Center for Molecular Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Bengt Persson
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-751 24 Uppsala, Sweden
- Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institutet, SE-171 21 Stockholm, Sweden
| | - Iftikhar Bangash
- EEG Department, Royal Oldham Hospital, OL1 2JH, Oldham, Lancashire, UK
| | - Krishna Das
- Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
- Young Epilepsy, RH7 6PW, Lingfield, Surrey, UK
| | - Deborah Hughes
- Department of Molecular Neuroscience, UCL Institute of Neurology, WC1N 3BG, London, UK
| | - Nicole Lesko
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
- Department of Laboratory Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Joakim Lundeberg
- Science for Life Laboratory, School of Biotechnology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Rod C. Scott
- Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
- Department of Neurological Sciences, University of Vermont College of Medicine, Vermont, VT 05405, USA
- Department of Paediatric Neurology, Fletcher Allen Health Care, Vermont, VT 05401, USA
- Clinical Neurosciences, Developmental Neurosciences Programme, UCL Institute of Child Health, London, WC1N 1EH, London, UK
| | - Annapurna Poduri
- Department of Neurology, Epilepsy Genetics Programme, Boston Children's Hospital, Boston, Massachusetts, Massachusetts 02115, USA
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, Massachusetts 02115, USA
| | - Ingrid E. Scheffer
- Department of Medicine and Paediatrics, University of Melbourne, Austin Health and Royal Children's Hospital, Melbourne, Victoria, VIC 3052, Australia
- Florey Institute, Melbourne, Victoria, VIC 3010, Australia
| | - Holly Smith
- MRC Laboratory for Molecular Cell Biology, UCL, London, WC1E 6BT, UK
| | - Paul Gissen
- MRC Laboratory for Molecular Cell Biology, UCL, London, WC1E 6BT, UK
- Department of Metabolic Medicine, Great Ormond Street Hospital, London, WC1N 3JH, UK
- Genetics and Genomic Medicine, Institute of Child Health, UCL, London, WC1N 1EH, UK
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Maarten E. A. Reith
- Department of Psychiatry, New York University School of Medicine, New York, New York 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
| | - Maya Topf
- Institute of Structural and Molecular Biology, Crystallography/Department of Biological Sciences, Birkbeck College, University of London, WC1E 7HX, UK
| | - Dimitri M. Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Robert J. Harvey
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK
| | - Anna Wedell
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Center for Molecular Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Manju A. Kurian
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Institute of Child Health, London WC1N 1EH, UK
- Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
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12
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Gackière F, Vinay L. Contribution of the potassium-chloride cotransporter KCC2 to the strength of inhibition in the neonatal rodent spinal cord in vitro. J Neurosci 2015; 35:5307-16. [PMID: 25834055 PMCID: PMC6705413 DOI: 10.1523/jneurosci.1674-14.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 02/16/2015] [Accepted: 02/26/2015] [Indexed: 11/21/2022] Open
Abstract
In healthy mature motoneurons (MNs), KCC2 cotransporters maintain the intracellular chloride concentration at low levels, a prerequisite for postsynaptic inhibition mediated by GABA and glycine. KCC2 expression in lumbar MNs is reduced after spinal cord injury (SCI) resulting in a depolarizing shift of the chloride equilibrium potential. Despite modeling studies indicating that such a downregulation of KCC2 function would reduce the strength of postsynaptic inhibition, physiological evidence is still lacking. The present study aimed at investigating the functional impact of a modification of KCC2 function. We focused on a well characterized disynaptic inhibitory pathway responsible for reciprocal inhibition between antagonistic muscles. We performed in vitro extracellular recordings on spinal cords isolated from rodents at the end of the first postnatal week. Genetic reduction of KCC2 expression, pharmacological blockade of KCC2, as well as SCI-induced downregulation of KCC2 all resulted in a reduction of the strength of reciprocal inhibition. We then tried to restore endogenous inhibition after SCI by means of zinc ions that have been shown to boost KCC2 function in other models. Zinc chloride indeed hyperpolarized the chloride equilibrium potential in MNs and increased reciprocal inhibition after neonatal SCI. This study demonstrates that the level of KCC2 function sets the strength of postsynaptic inhibition and suggests that the downregulation of KCC2 after SCI likely contributes to the high occurrence of flexor-extensor cocontractions in SCI patients.
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Affiliation(s)
- Florian Gackière
- Institut de Neurosciences de la Timone, UMR 7289, CNRS, Aix Marseille Université, 13385 Marseille cx 5, France
| | - Laurent Vinay
- Institut de Neurosciences de la Timone, UMR 7289, CNRS, Aix Marseille Université, 13385 Marseille cx 5, France
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13
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Vlasits AL, Bos R, Morrie RD, Fortuny C, Flannery JG, Feller MB, Rivlin-Etzion M. Visual stimulation switches the polarity of excitatory input to starburst amacrine cells. Neuron 2014; 83:1172-84. [PMID: 25155960 PMCID: PMC4161675 DOI: 10.1016/j.neuron.2014.07.037] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2014] [Indexed: 11/22/2022]
Abstract
Direction-selective ganglion cells (DSGCs) are tuned to motion in one direction. Starburst amacrine cells (SACs) are thought to mediate this direction selectivity through precise anatomical wiring to DSGCs. Nevertheless, we previously found that visual adaptation can reverse DSGCs's directional tuning, overcoming the circuit anatomy. Here we explore the role of SACs in the generation and adaptation of direction selectivity. First, using pharmacogenetics and two-photon calcium imaging, we validate that SACs are necessary for direction selectivity. Next, we demonstrate that exposure to an adaptive stimulus dramatically alters SACs' synaptic inputs. Specifically, after visual adaptation, On-SACs lose their excitatory input during light onset but gain an excitatory input during light offset. Our data suggest that visual stimulation alters the interactions between rod- and cone-mediated inputs that converge on the terminals of On-cone BCs. These results demonstrate how the sensory environment can modify computations performed by anatomically defined neuronal circuits.
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Affiliation(s)
- Anna L Vlasits
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Rémi Bos
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ryan D Morrie
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Cécile Fortuny
- Vision Science Graduate Program, University of California, Berkeley, Berkeley, CA 94720, USA
| | - John G Flannery
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Vision Science Graduate Program, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Marla B Feller
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Michal Rivlin-Etzion
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, 76100, Israel.
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14
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Souchet B, Guedj F, Sahún I, Duchon A, Daubigney F, Badel A, Yanagawa Y, Barallobre MJ, Dierssen M, Yu E, Herault Y, Arbones M, Janel N, Créau N, Delabar JM. Excitation/inhibition balance and learning are modified by Dyrk1a gene dosage. Neurobiol Dis 2014; 69:65-75. [PMID: 24801365 DOI: 10.1016/j.nbd.2014.04.016] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 04/17/2014] [Accepted: 04/24/2014] [Indexed: 11/21/2022] Open
Abstract
Cognitive deficits in Down syndrome (DS) have been linked to increased synaptic inhibition, leading to an imbalance of excitation/inhibition (E/I). Various mouse models and studies from human brains have implicated an HSA21 gene, the serine/threonine kinase DYRK1A, as a candidate for inducing cognitive dysfunction. Here, consequences of alterations in Dyrk1a dosage were assessed in mouse models with varying copy numbers of Dyrk1a: mBACtgDyrk1a, Ts65Dn and Dp(16)1Yey (with 3 gene copies) and Dyrk1a(+/-) (one functional copy). Molecular (i.e. immunoblotting/immunohistochemistry) and behavioral analyses (e.g., rotarod, Morris water maze, Y-maze) were performed in mBACtgDyrk1a mice. Increased expression of DYRK1A in mBACtgDyrk1a induced molecular alterations in synaptic plasticity pathways, particularly expression changes in GABAergic and glutaminergic related proteins. Similar alterations were observed in models with partial trisomy of MMU16, Ts65Dn and Dp(16)1Yey, and were reversed in the Dyrk1a(+/-) model. Dyrk1a overexpression produced an increased number and signal intensity of GAD67 positive neurons, indicating enhanced inhibition pathways in three different models: mBACtgDyrk1a, hYACtgDyrk1a and Dp(16)1Yey. Functionally, Dyrk1a overexpression protected mice from PTZ-induced seizures related to GABAergic neuron plasticity. Our study shows that DYRK1A overexpression affects pathways involved in synaptogenesis and synaptic plasticity and influences E/I balance toward inhibition. Inhibition of DYRK1A activity offers a therapeutic target for DS, but its inhibition/activation may also be relevant for other psychiatric diseases with E/I balance alterations.
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Affiliation(s)
- Benoit Souchet
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Fayçal Guedj
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Ignasi Sahún
- Genomic Regulation Center, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Arnaud Duchon
- IGBMC, CNRS, INSERM, UMR7104, UMR964, Illkirch, France
| | - Fabrice Daubigney
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Anne Badel
- MTI, Univ Paris Diderot, Sorbonne Paris Cité, France
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine and JST, CREST, Japan
| | - Maria Jose Barallobre
- Plataforma de Recerca Aplicada en Animal de Laboratori (PRAAL), Parc Científic de Barcelona (PCB), Spain
| | - Mara Dierssen
- Genomic Regulation Center, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Eugene Yu
- Children's Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
| | - Yann Herault
- IGBMC, CNRS, INSERM, UMR7104, UMR964, Illkirch, France
| | - Mariona Arbones
- Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain; Plataforma de Recerca Aplicada en Animal de Laboratori (PRAAL), Parc Científic de Barcelona (PCB), Spain
| | - Nathalie Janel
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Nicole Créau
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France.
| | - Jean Maurice Delabar
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France.
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15
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Tadros MA, Farrell KE, Schofield PR, Brichta AM, Graham BA, Fuglevand AJ, Callister RJ. Intrinsic and synaptic homeostatic plasticity in motoneurons from mice with glycine receptor mutations. J Neurophysiol 2014; 111:1487-98. [PMID: 24401707 PMCID: PMC4839488 DOI: 10.1152/jn.00728.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/04/2014] [Indexed: 12/12/2022] Open
Abstract
Inhibitory synaptic inputs to hypoglossal motoneurons (HMs) are important for modulating excitability in brainstem circuits. Here we ask whether reduced inhibition, as occurs in three murine mutants with distinct naturally occurring mutations in the glycine receptor (GlyR), leads to intrinsic and/or synaptic homeostatic plasticity. Whole cell recordings were obtained from HMs in transverse brainstem slices from wild-type (wt), spasmodic (spd), spastic (spa), and oscillator (ot) mice (C57Bl/6, approximately postnatal day 21). Passive and action potential (AP) properties in spd and ot HMs were similar to wt. In contrast, spa HMs had lower input resistances, more depolarized resting membrane potentials, higher rheobase currents, smaller AP amplitudes, and slower afterhyperpolarization current decay times. The excitability of HMs, assessed by "gain" in injected current/firing-frequency plots, was similar in all strains whereas the incidence of rebound spiking was increased in spd. The difference between recruitment and derecruitment current (i.e., ΔI) for AP discharge during ramp current injection was more negative in spa and ot. GABAA miniature inhibitory postsynaptic current (mIPSC) amplitude was increased in spa and ot but not spd, suggesting diminished glycinergic drive leads to compensatory adjustments in the other major fast inhibitory synaptic transmitter system in these mutants. Overall, our data suggest long-term reduction in glycinergic drive to HMs results in changes in intrinsic and synaptic properties that are consistent with homeostatic plasticity in spa and ot but not in spd. We propose such plasticity is an attempt to stabilize HM output, which succeeds in spa but fails in ot.
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Affiliation(s)
- M. A. Tadros
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
| | - K. E. Farrell
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
| | - P. R. Schofield
- Neuroscience Research Australia and School of Medical Sciences, University of New South Wales, Randwick, Australia; and
| | - A. M. Brichta
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
| | - B. A. Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
| | - A. J. Fuglevand
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona
| | - R. J. Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
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16
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Dey D, Eckle VS, Vitko I, Sullivan KA, Lasiecka ZM, Winckler B, Stornetta RL, Williamson JM, Kapur J, Perez-Reyes E. A potassium leak channel silences hyperactive neurons and ameliorates status epilepticus. Epilepsia 2014; 55:203-13. [PMID: 24299204 PMCID: PMC4161023 DOI: 10.1111/epi.12472] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2013] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To develop a constitutively active K(+) leak channel using TREK-1 (TWIK-related potassium channel 1; TREK-M) that is resistant to compensatory down-regulation by second messenger cascades, and to validate the ability of TREK-M to silence hyperactive neurons using cultured hippocampal neurons. To test if adenoassociated viral (AAV) delivery of TREK-M could reduce the duration of status epilepticus and reduce neuronal death induced by lithium-pilocarpine administration. METHODS Molecular cloning techniques were used to engineer novel vectors to deliver TREK-M via plasmids, lentivirus, and AAV using a cytomegalovirus (CMV)-enhanced GABRA4 promoter. Electrophysiology was used to characterize the activity and regulation of TREK-M in human embryonic kidney (HEK-293) cells, and the ability to reduce spontaneous activity in cultured hippocampal neurons. Adult male rats were injected bilaterally with self-complementary AAV particles composed of serotype 5 capsid into the hippocampus and entorhinal cortex. Lithium-pilocarpine was used to induce status epilepticus. Seizures were monitored using continuous video-electroencephalography (EEG) monitoring. Neuronal death was measured using Fluoro-Jade C staining of paraformaldehyde-fixed brain slices. RESULTS TREK-M inhibited neuronal firing by hyperpolarizing the resting membrane potential and decreasing input resistance. AAV delivery of TREK-M decreased the duration of status epilepticus by 50%. Concomitantly it reduced neuronal death in areas targeted by the AAV injection. SIGNIFICANCE These findings demonstrate that TREK-M can silence hyperexcitable neurons in the brain of epileptic rats and treat acute seizures. This study paves the way for an alternative gene therapy treatment of status epilepticus, and provides the rationale for studies of AAV-TREK-M's effect on spontaneous seizures in chronic models of temporal lobe epilepsy.
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Affiliation(s)
- Deblina Dey
- Departments of Pharmacology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
- Neuroscience Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Veit-Simon Eckle
- Departments of Pharmacology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Iuliia Vitko
- Departments of Pharmacology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Kyle A. Sullivan
- Departments of Pharmacology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
- Undergraduate School of Arts and Sciences, University of Virginia, Charlottesville, Virginia, U.S.A
| | - Zofia M. Lasiecka
- Department of Neuroscience, Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Bettina Winckler
- Neuroscience Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
- Department of Neuroscience, Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Ruth L. Stornetta
- Departments of Pharmacology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - John M. Williamson
- Department of Neurology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Jaideep Kapur
- Neuroscience Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
- Department of Neurology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
| | - Edward Perez-Reyes
- Departments of Pharmacology, Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
- Neuroscience Graduate Program University of Virginia School of Medicine, Charlottesville, Virginia, U.S.A
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17
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Ono Y, Tanaka H, Takata M, Nagahara Y, Noda Y, Tsuruma K, Shimazawa M, Hozumi I, Hara H. SA4503, a sigma-1 receptor agonist, suppresses motor neuron damage in in vitro and in vivo amyotrophic lateral sclerosis models. Neurosci Lett 2014; 559:174-8. [PMID: 24334165 DOI: 10.1016/j.neulet.2013.12.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/07/2013] [Accepted: 12/04/2013] [Indexed: 12/17/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease. Recently, it has been reported that a mutation in the sigma-1 receptor causes juvenile ALS. Therefore, the function of the sigma-1 receptor may be important in the pathology of ALS. In the present study, we investigated the effect of SA4503, a sigma-1 receptor agonist, against in in vitro and in vivo ALS models. We first investigated whether SA4503, a sigma-1 receptor agonist, prevented superoxide dismutase 1 (SOD1(G93A))- and serum free-induced cell death of mice motor neuron cells (NSC34) in in vitro model of an ALS. At concentrations of 1-10μM, SA4503 reduced SOD1(G93A)-induced cell death in a concentration-dependent manner, and BD1047, a sigma-1 receptor antagonist, inhibited the protective effect of SA4503. Next, we investigated whether SA4503 affected the phosphorylation levels of Akt (Ser 473) and extracellular signal-regulated kinase (ERK) 1/2 and the expression of the sigma-1 receptor. SA4503 promoted the phosphorylation of Akt (Ser 473) and ERK1/2 in a time-dependent manner, but SA4503 did not affect the expression of the sigma-1 receptor. These results suggest that the protective effect of SA4503 might be involved in promoting the phosphorylation of Akt and ERK1/2. We then investigated whether SA4503 suppressed the progression of ALS in an SOD1(G93A) ALS mouse model. SA4503 did not affect the onset time of ALS. However, it significantly extended the survival time in the SOD1(G93A) mice compared with a vehicle-treated group. These findings indicate that SA4503 is effective in suppressing motor neuron degeneration and symptom progression in ALS.
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Affiliation(s)
- Yoko Ono
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Hirotaka Tanaka
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Masafumi Takata
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Yuki Nagahara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Yasuhiro Noda
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Kazuhiro Tsuruma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Isao Hozumi
- Department of Medical Therapeutics and Molecular Therapeutics, Gifu Pharmaceutical University, Gifu, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
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18
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Christian CA, Herbert AG, Holt RL, Peng K, Sherwood KD, Pangratz-Fuehrer S, Rudolph U, Huguenard JR. Endogenous positive allosteric modulation of GABA(A) receptors by diazepam binding inhibitor. Neuron 2013; 78:1063-74. [PMID: 23727119 DOI: 10.1016/j.neuron.2013.04.026] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2013] [Indexed: 11/30/2022]
Abstract
Benzodiazepines (BZs) allosterically modulate γ-aminobutyric acid type-A receptors (GABAARs) to increase inhibitory synaptic strength. Diazepam binding inhibitor (DBI) protein is a BZ site ligand expressed endogenously in the brain, but functional evidence for BZ-mimicking positive modulatory actions has been elusive. We demonstrate an endogenous potentiation of GABAergic synaptic transmission and responses to GABA uncaging in the thalamic reticular nucleus (nRT) that is absent in both nm1054 mice, in which the Dbi gene is deleted, and mice in which BZ binding to α3 subunit-containing GABAARs is disrupted. Viral transduction of DBI into nRT is sufficient to rescue the endogenous potentiation of GABAergic transmission in nm1054 mice. Both mutations enhance thalamocortical spike-and-wave discharges characteristic of absence epilepsy. Together, these results indicate that DBI mediates endogenous nucleus-specific BZ-mimicking ("endozepine") roles to modulate nRT function and suppress thalamocortical oscillations. Enhanced DBI signaling might serve as a therapy for epilepsy and other neurological disorders.
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Affiliation(s)
- Catherine A Christian
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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19
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Farrow K, Teixeira M, Szikra T, Viney TJ, Balint K, Yonehara K, Roska B. Ambient illumination toggles a neuronal circuit switch in the retina and visual perception at cone threshold. Neuron 2013; 78:325-38. [PMID: 23541902 DOI: 10.1016/j.neuron.2013.02.014] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 11/17/2022]
Abstract
VIDEO ABSTRACT Gradual changes in the sensory environment can lead to abrupt changes in brain computations and perception. However, mechanistic understanding of the mediating microcircuits is missing. By sliding through light levels from starlight to daylight, we identify retinal ganglion cell types in the mouse that abruptly and reversibly switch the weighting of center and surround interactions in their receptive field around cone threshold. Two-photon-targeted recordings and genetic and viral tracing experiments revealed that the circuit element responsible for the switch is a large inhibitory neuron that provides direct inhibition to ganglion cells. Our experiments suggest that weak excitatory input via electrical synapses together with the spiking threshold in inhibitory cells act as a switch. We also reveal a switch-like component in the spatial integration properties of human vision at cone threshold. This work demonstrates that circuits in the retina can quickly and reversibly switch between two distinct states, implementing distinct perceptual regimes at different light levels.
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Affiliation(s)
- Karl Farrow
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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20
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Petrash HA, Philbrook A, Haburcak M, Barbagallo B, Francis MM. ACR-12 ionotropic acetylcholine receptor complexes regulate inhibitory motor neuron activity in Caenorhabditis elegans. J Neurosci 2013; 33:5524-32. [PMID: 23536067 PMCID: PMC3645261 DOI: 10.1523/jneurosci.4384-12.2013] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/23/2013] [Accepted: 02/04/2013] [Indexed: 12/11/2022] Open
Abstract
Heterogeneity in the composition of neurotransmitter receptors is thought to provide functional diversity that may be important in patterning neural activity and shaping behavior (Dani and Bertrand, 2007; Sassoè-Pognetto, 2011). However, this idea has remained difficult to evaluate directly because of the complexity of neuronal connectivity patterns and uncertainty about the molecular composition of specific receptor types in vivo. Here we dissect how molecular diversity across receptor types contributes to the coordinated activity of excitatory and inhibitory motor neurons in the nematode Caenorhabditis elegans. We show that excitatory and inhibitory motor neurons express distinct populations of ionotropic acetylcholine receptors (iAChRs) requiring the ACR-12 subunit. The activity level of excitatory motor neurons is influenced through activation of nonsynaptic iAChRs (Jospin et al., 2009; Barbagallo et al., 2010). In contrast, synaptic coupling of excitatory and inhibitory motor neurons is achieved through a second population of iAChRs specifically localized at postsynaptic sites on inhibitory motor neurons. Loss of ACR-12 iAChRs from inhibitory motor neurons leads to reduced synaptic drive, decreased inhibitory neuromuscular signaling, and variability in the sinusoidal motor pattern. Our results provide new insights into mechanisms that establish appropriately balanced excitation and inhibition in the generation of a rhythmic motor behavior and reveal functionally diverse roles for iAChR-mediated signaling in this process.
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Affiliation(s)
- Hilary A Petrash
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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21
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Schneider A, Ballinger E, Chavez A, Tassone F, Hagerman RJ, Hessl D. Prepulse inhibition in patients with fragile X-associated tremor ataxia syndrome. Neurobiol Aging 2012; 33:1045-53. [PMID: 20961665 PMCID: PMC3044775 DOI: 10.1016/j.neurobiolaging.2010.09.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 08/23/2010] [Accepted: 09/05/2010] [Indexed: 11/25/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late onset neurodegenerative disorder that affects carriers of the fragile X premutation, typically after age 50. Common symptoms include intention tremor, ataxia, neuropathy, autonomic dysfunction, cognitive decline, and dementia. The objectives of this study were to determine if patients with FXTAS have altered prepulse inhibition (PPI; a measure of sensorimotor gating), and to study possible correlations between PPI, molecular status, and cognitive performance. A passive acoustic PPI paradigm was applied in 163 subjects; 121 carriers of the fragile X premutation, and 42 healthy controls. There were significant differences in PPI between premutation carriers with FXTAS and controls at PPI 60 ms, and at 120 ms. This effect was more prominent in the male FXTAS patients. There was a tendency to an impaired PPI in female premutation carriers at the 120 ms condition. There was a significant correlation between the PPI deficit and a higher CGG repeat number. The results show an impairment in sensorimotor gating processes in male carriers of the fragile X premutation, which is more prominent in patients with FXTAS.
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Affiliation(s)
- Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California at Davis, Sacramento, CA 95817, USA.
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22
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Viñals X, Molas S, Gallego X, Fernández-Montes RD, Robledo P, Dierssen M, Maldonado R. Overexpression of α3/α5/β4 nicotinic receptor subunits modifies impulsive-like behavior. Drug Alcohol Depend 2012; 122:247-52. [PMID: 22024278 DOI: 10.1016/j.drugalcdep.2011.09.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 08/01/2011] [Accepted: 09/17/2011] [Indexed: 12/20/2022]
Abstract
Recent studies have revealed that sequence variants in genes encoding the α3/α5/β4 nicotinic acetylcholine receptor subunits are associated with nicotine dependence. In this study, we evaluated two specific aspects of executive functioning related to drug addiction (impulsivity and working memory) in transgenic mice over expressing α3/α5/β4 nicotinic receptor subunits. Impulsivity and working memory were evaluated in an operant delayed alternation task, where mice must inhibit responding between 2 and 8s in order to receive food reinforcement. Working memory was also evaluated in a spontaneous alternation task in an open field. Transgenic mice showed less impulsive-like behavior than wild-type controls, and this behavioral phenotype was related to the number of copies of the transgene. Thus, transgenic Line 22 (16-28 copies) showed a more pronounced phenotype than Line 30 (4-5 copies). Overexpression of these subunits in Line 22 reduced spontaneous alternation behavior suggesting deficits in working memory processing in this particular paradigm. These results reveal the involvement of α3/α5/β4 nicotinic receptor subunits in working memory and impulsivity, two behavioral traits directly related to the vulnerability to develop nicotine dependence.
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Affiliation(s)
- Xavier Viñals
- Laboratory of Neuropharmacology, Pompeu Fabra University, PRBB, Barcelona, Spain
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23
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Antonucci F, Alpár A, Kacza J, Caleo M, Verderio C, Giani A, Martens H, Chaudhry FA, Allegra M, Grosche J, Michalski D, Erck C, Hoffmann A, Harkany T, Matteoli M, Härtig W. Cracking down on inhibition: selective removal of GABAergic interneurons from hippocampal networks. J Neurosci 2012; 32:1989-2001. [PMID: 22323713 PMCID: PMC3742881 DOI: 10.1523/jneurosci.2720-11.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 12/07/2011] [Accepted: 12/14/2011] [Indexed: 12/12/2022] Open
Abstract
Inhibitory (GABAergic) interneurons entrain assemblies of excitatory principal neurons to orchestrate information processing in the hippocampus. Disrupting the dynamic recruitment as well as the temporally precise activity of interneurons in hippocampal circuitries can manifest in epileptiform seizures, and impact specific behavioral traits. Despite the importance of GABAergic interneurons during information encoding in the brain, experimental tools to selectively manipulate GABAergic neurotransmission are limited. Here, we report the selective elimination of GABAergic interneurons by a ribosome inactivation approach through delivery of saporin-conjugated anti-vesicular GABA transporter antibodies (SAVAs) in vitro as well as in the mouse and rat hippocampus in vivo. We demonstrate the selective loss of GABAergic--but not glutamatergic--synapses, reduced GABA release, and a shift in excitation/inhibition balance in mixed cultures of hippocampal neurons exposed to SAVAs. We also show the focal and indiscriminate loss of calbindin(+), calretinin(+), parvalbumin/system A transporter 1(+), somatostatin(+), vesicular glutamate transporter 3 (VGLUT3)/cholecystokinin/CB(1) cannabinoid receptor(+) and neuropeptide Y(+) local-circuit interneurons upon SAVA microlesions to the CA1 subfield of the rodent hippocampus, with interneuron debris phagocytosed by infiltrating microglia. SAVA microlesions did not affect VGLUT1(+) excitatory afferents. Yet SAVA-induced rearrangement of the hippocampal circuitry triggered network hyperexcitability associated with the progressive loss of CA1 pyramidal cells and the dispersion of dentate granule cells. Overall, our data identify SAVAs as an effective tool to eliminate GABAergic neurons from neuronal circuits underpinning high-order behaviors and cognition, and whose manipulation can recapitulate pathogenic cascades of epilepsy and other neuropsychiatric illnesses.
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Affiliation(s)
- Flavia Antonucci
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
- Fondazione Filarete, I-20129 Milan, Italy
| | - Alán Alpár
- Division of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Johannes Kacza
- Institute of Veterinary Anatomy, University of Leipzig, D-04103 Leipzig, Germany
| | - Matteo Caleo
- CNR Institute of Neuroscience, I-51600 Pisa, Italy
| | - Claudia Verderio
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
| | - Alice Giani
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
| | | | - Farrukh A. Chaudhry
- The Biotechnology Centre of Oslo & Centre for Molecular Biology and Neuroscience, University of Oslo, N-0317 Oslo, Norway
| | | | - Jens Grosche
- Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany
| | - Dominik Michalski
- Department of Neurology, University of Leipzig, D-04103 Leipzig, Germany
| | | | - Anke Hoffmann
- Institute of Veterinary Anatomy, University of Leipzig, D-04103 Leipzig, Germany
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
- European Neuroscience Institute, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom, and
| | - Michela Matteoli
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
- Instituto Clinico Humanitas, IRCCS, Rozzano, I-20089 Milan, Italy
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany
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24
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Abstract
Recent studies suggest that l-glutamate may be an efferent transmitter released from axons innervating taste buds. In this report, we determined the types of ionotropic synaptic glutamate receptors present on taste cells and that underlie this postulated efferent transmission. We also studied what effect glutamate exerts on taste bud function. We isolated mouse taste buds and taste cells, conducted functional imaging using Fura 2, and used cellular biosensors to monitor taste-evoked transmitter release. The findings show that a large fraction of Presynaptic (Type III) taste bud cells (∼50%) respond to 100 µM glutamate, NMDA, or kainic acid (KA) with an increase in intracellular Ca(2+). In contrast, Receptor (Type II) taste cells rarely (4%) responded to 100 µM glutamate. At this concentration and with these compounds, these agonists activate glutamatergic synaptic receptors, not glutamate taste (umami) receptors. Moreover, applying glutamate, NMDA, or KA caused taste buds to secrete 5-HT, a Presynaptic taste cell transmitter, but not ATP, a Receptor cell transmitter. Indeed, glutamate-evoked 5-HT release inhibited taste-evoked ATP secretion. The findings are consistent with a role for glutamate in taste buds as an inhibitory efferent transmitter that acts via ionotropic synaptic glutamate receptors.
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MESH Headings
- Animals
- CHO Cells
- Cricetinae
- Cricetulus
- Glutamic Acid/metabolism
- Glutamic Acid/pharmacology
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neural Inhibition/drug effects
- Neural Inhibition/genetics
- Neural Inhibition/physiology
- Neurons, Efferent/drug effects
- Neurons, Efferent/metabolism
- Neurons, Efferent/physiology
- Neurotransmitter Agents/metabolism
- Neurotransmitter Agents/pharmacology
- Phospholipase C beta/genetics
- Receptor, Serotonin, 5-HT2C/genetics
- Receptor, Serotonin, 5-HT2C/metabolism
- Receptors, Purinergic P2X2/genetics
- Receptors, Purinergic P2X2/metabolism
- Receptors, Purinergic P2X3/genetics
- Receptors, Purinergic P2X3/metabolism
- Synaptic Transmission/drug effects
- Synaptic Transmission/genetics
- Taste Buds/drug effects
- Taste Buds/metabolism
- Taste Buds/physiology
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Affiliation(s)
- Yijen A Huang
- Department of Physiology and Biophysics, University of Miami School of Medicine, Miami, Florida, United States of America.
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25
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Abstract
Sensorimotor gating, or the ability of a sensory event to suppress a motor response, can be measured operationally via prepulse inhibition (PPI) of the startle response. PPI is deficient in schizophrenia patients as well as other neuropsychiatric disorders, can be measured across species, and has been used widely as a translational tool in preclinical neuropharmacological and genetic research. First developed to assess drug effects in pharmacological and developmental models, PPI has become one of the standard behavioral measures in genetic models of schizophrenia and other neuropsychiatric disorders that exhibit PPI deficits. In this chapter we review the literature on genetic models of sensorimotor gating and discuss the utility of PPI as a tool in phenotyping mutant mouse models. We highlight the approaches to genetic mouse models of neuropsychiatric disease, discuss some of the important caveats to these approaches, and provide a comprehensive table covering the more recent genetic models that have evaluated PPI.
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Affiliation(s)
- Susan B. Powell
- Department of Psychiatry, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0804, USA
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Martin Weber
- Department of Neuroscience, Genentech Inc, 1 DNA Way, South San Francisco, CA 94080-4990, USA
| | - Mark A. Geyer
- Department of Psychiatry, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0804, USA
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA
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26
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Ye X, Tai W, Zhang D. The early events of Alzheimer's disease pathology: from mitochondrial dysfunction to BDNF axonal transport deficits. Neurobiol Aging 2011; 33:1122.e1-10. [PMID: 22212405 DOI: 10.1016/j.neurobiolaging.2011.11.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/01/2011] [Accepted: 11/04/2011] [Indexed: 01/05/2023]
Abstract
Although there are numerous studies regarding Alzheimer's disease (AD), the cause and progression of AD are still not well understood. The researches in the past decade implicated amyloid-beta (Aβ) overproduction as a causative event in disease pathogenesis, but still failed to clarify the mechanism of pathology from Aβ production to central neural system defects in AD. The present review raises the hypothesis that the onset of AD pathology is closely related with mitochondrial dysfunction induced by Aβ and brain-derived neurotrophic factor (BDNF) axonal transport deficits. It is well-known that axonal transport defect and attenuation of BDNF-neurotrophic tyrosine receptor kinase 2 (TrkB) signal are fatal to neuronal function and survival. We hypothesized that abnormal amyloid precursor protein (APP) processing and Aβ production in mitochondria disturb the axonal transport by impairing mitochondrial function and attenuate BDNF-neurotrophic tyrosine receptor kinase 2 signal subsequently. For this hypothesis, the factors related with the initiation of AD pathology are not only limited to the neurons per se but also expanded to the microenvironment around neurons, such as the secretion of BDNF from astrocytes. The modification of the origin in this pathway may contribute to slow down the disease progression of AD.
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Affiliation(s)
- Xuan Ye
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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27
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Andó RD, Bíró J, Csölle C, Ledent C, Sperlágh B. The inhibitory action of exo- and endocannabinoids on [³H]GABA release are mediated by both CB₁and CB₂receptors in the mouse hippocampus. Neurochem Int 2011; 60:145-52. [PMID: 22133429 DOI: 10.1016/j.neuint.2011.11.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 10/19/2011] [Accepted: 11/15/2011] [Indexed: 11/15/2022]
Abstract
Exogenous and endogenous cannabinoids play an important role in modulating the release of neurotransmitters in hippocampal excitatory and inhibitory networks, thus having profound effect on higher cognitive and emotional functions such as learning and memory. In this study we have studied the effect of cannabinoid agonists on the potassium depolarization-evoked [(3)H]GABA release from hippocampal synaptosomes in the wild-type (WT) and cannabinoid 1 receptor (CB(1)R)-null mutant mice. All tested cannabinoid agonists (WIN55,212-2, CP55,940, HU-210, 2-arachidonoyl-glycerol, 2-AG; delta-9-tetra-hydrocannabinol, THC) inhibited [(3)H]GABA release in WT mice with the following rank order of agonist potency: HU-210>CP55,490>WIN55,212-2>>2-AG>THC. By contrast, 2-AG and THC displayed the greatest efficacy eliciting almost complete inhibition of evoked [(3)H]GABA efflux, whereas the maximal inhibition obtained by HU-210, CP55,490, and WIN55,212-2 were less, eliciting not more than 40% inhibition. The inhibitory effect of WIN55,212-2, THC and 2-AG on evoked [(3)H]GABA efflux was antagonized by the CB(1) receptor inverse agonist AM251 (0.5 μM) in the WT mice. In the CB(1)R knockout mice the inhibitory effects of all three agonists were attenuated. In these mice, AM251 did not antagonize, but further reduced the [(3)H]GABA release in the presence of the synthetic agonist WIN55,212-2. By contrast, the concentration-dependent inhibitory effects of THC and 2-AG were partially antagonized by AM251 in the absence of CB(1) receptors. Finally, the inhibition of evoked [(3)H]GABA efflux by THC and 2-AG was also partially attenuated by AM630 (1 μM), the CB(2) receptor-selective antagonist, both in WT and CB(1) knockout mice. Our data prove the involvement of CB(1) receptors in the effect of exo- and endocannabinoids on GABA efflux from hippocampal nerve terminals. In addition, in the effect of the exocannabinoid THC and the endocannabinoid 2-AG, non-CB(1), probably CB(2)-like receptors are also involved.
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MESH Headings
- Animals
- Cannabinoid Receptor Modulators/physiology
- Cannabinoids/pharmacology
- Endocannabinoids
- Hippocampus/metabolism
- Hippocampus/physiology
- Male
- Mice
- Mice, Inbred Strains
- Mice, Knockout
- Neural Inhibition/genetics
- Neural Inhibition/physiology
- Presynaptic Terminals/metabolism
- Presynaptic Terminals/physiology
- Receptor, Cannabinoid, CB1/deficiency
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Tritium
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- Rómeó D Andó
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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28
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Wildeboer-Andrud KM, Stevens KE. The smoking cessation drug varenicline improves deficient P20-N40 inhibition in DBA/2 mice. Pharmacol Biochem Behav 2011; 100:17-24. [PMID: 21763340 PMCID: PMC3183147 DOI: 10.1016/j.pbb.2011.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 06/30/2011] [Accepted: 07/02/2011] [Indexed: 11/29/2022]
Abstract
Varenicline, an FDA approved smoking cessation pharmacotherapy, is an α4β2* nicotinic acetylcholine receptor (nAChR) partial agonist and an α7* nAChR full agonist. Both subtypes of nAChR are involved in modulating auditory evoked responses in rodents. In DBA/2 mice, an inbred strain, auditory evoked responses to paired auditory stimuli fail to inhibit to the second stimulus. This mouse strain replicates the auditory evoked response inhibition deficit experienced by the majority of schizophrenia patients. In this current study, we examined the effects of five different doses of varenicline (0.06, 0.3, 0.6, 3 and 6mg/kg) on auditory evoked responses in anesthetized DBA/2 mice. We also administered α4β2* and α7* nAChR selective antagonists prior to varenicline administration to determine which nAChR subtypes mediate the effects of varenicline. Four of the five doses of varenicline produced improvements in auditory evoked response inhibition deficits. Selective blockade of either the α4β2* or α7* nAChR in competition with 0.6mg/kg varenicline prevented varenicline induced improvements. In competition with a higher dose of varenicline (3mg/kg) only blockade of the α4β2* nAChR prevented varenicline induced improvement in auditory evoked response inhibition. These data indicate the importance of α4β2* nAChRs and the potential involvement of the α7* subtype in varenicline's effects on auditory evoked responses in DBA/2 mice.
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Ramos OV, Torterolo P, Lim V, Chase MH, Sampogna S, Yamuy J. The role of mesopontine NGF in sleep and wakefulness. Brain Res 2011; 1413:9-23. [PMID: 21840513 PMCID: PMC3189444 DOI: 10.1016/j.brainres.2011.06.066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 06/27/2011] [Accepted: 06/30/2011] [Indexed: 10/18/2022]
Abstract
The microinjection of nerve growth factor (NGF) into the cat pontine tegmentum rapidly induces rapid eye movement (REM) sleep. To determine if NGF is involved in naturally-occurring REM sleep, we examined whether it is present in mesopontine cholinergic structures that promote the initiation of REM sleep, and whether the blockade of NGF production in these structures suppresses REM sleep. We found that cholinergic neurons in the cat dorso-lateral mesopontine tegmentum exhibited NGF-like immunoreactivity. In addition, the microinjection of an oligodeoxyribonucleotide (OD) directed against cat NGF mRNA into this region resulted in a reduction in the time spent in REM sleep in conjunction with an increase in the time spent in wakefulness. Sleep and wakefulness returned to baseline conditions 2 to 5 days after antisense OD administration. The preceding antisense OD-induced effects occurred in conjunction with the suppression of NGF-like immunoreactivity within the site of antisense OD injection. These data support the hypothesis that NGF is involved in the modulation of naturally-occurring sleep and wakefulness.
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Affiliation(s)
| | - Pablo Torterolo
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Vincent Lim
- Websciences International, Los Angeles, CA, 90024
| | - Michael H. Chase
- Websciences International, Los Angeles, CA, 90024
- UCLA School of Medicine Los Angeles, CA, 90024
| | | | - Jack Yamuy
- VA Greater Los Angeles Healthcare System, Los Angeles, CA, 90073
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Abstract
The cerebral cortex has a central role in cognitive and emotional processing. As such, understanding the mechanisms that govern its development and function will be central to understanding the bases of severe neuropsychiatric disorders, particularly those that first appear in childhood. In this review, I highlight recent progress in elucidating genetic, molecular and cellular mechanisms that control cortical development. I discuss basic aspects of cortical developmental anatomy, and mechanisms that regulate cortical size and area formation, with an emphasis on the roles of fibroblast growth factor (Fgf) signaling and specific transcription factors. I then examine how specific types of cortical excitatory projection neurons are generated, and how their axons grow along stereotyped pathways to their targets. Next, I address how cortical inhibitory (GABAergic) neurons are generated, and point out the role of these cells in controlling cortical plasticity and critical periods. The paper concludes with an examination of four possible developmental mechanisms that could contribute to some forms of neurodevelopmental disorders, such as autism.
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Affiliation(s)
- John L R Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, Center for Neurobiology and Psychiatry, Department of Psychiatry, University of California at San Francisco, CA 94158-2324, USA.
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Jusuf PR, Almeida AD, Randlett O, Joubin K, Poggi L, Harris WA. Origin and determination of inhibitory cell lineages in the vertebrate retina. J Neurosci 2011; 31:2549-62. [PMID: 21325522 PMCID: PMC3083844 DOI: 10.1523/jneurosci.4713-10.2011] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 11/18/2010] [Accepted: 12/14/2010] [Indexed: 11/21/2022] Open
Abstract
Multipotent progenitors in the vertebrate retina often generate clonally related mixtures of excitatory and inhibitory neurons. The postmitotically expressed transcription factor, Ptf1a, is essential for all inhibitory fates in the zebrafish retina, including three types of horizontal and 28 types of amacrine cell. Here, we show that specific types of inhibitory neurons arise from the cell-autonomous influence of Ptf1a in the daughters of fate-restricted progenitors, such as Ath5 or Vsx1/2-expressing progenitors, and that in the absence of Ptf1a, cells that would have become these specific inhibitory subtypes revert to the histogenetically appropriate excitatory subtypes of the same lineage. Altered proportions of amacrine subtypes respecified by the misexpression of Ptf1a in the Ath5 lineage suggest that Ath5-expressing progenitors are biased, favoring the generation of some subtypes more than others. Yet the full array of inhibitory cell subtypes in Ath5 mutants implies the existence of Ath5-independent factors involved in inhibitory cell specification. We also show that an extrinsic negative feedback on the expression of Ptf1a provides a control mechanism by which the number of any and all types of inhibitory cells in the retina can be regulated in this lineage-dependent way.
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Affiliation(s)
- Patricia R. Jusuf
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom, and
| | - Alexandra D. Almeida
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom, and
| | - Owen Randlett
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom, and
| | - Kathy Joubin
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom, and
| | - Lucia Poggi
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - William A. Harris
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom, and
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Yoon EH, Lee KJ, Kim YS, Chang MS, Lee SH, Park CH. Retinoid X receptor α acts as a negative regulator in Nurr1-induced dopaminergic differentiation in rat neural precursor cells. Neuroreport 2010; 21:1162-1166. [PMID: 22066143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
To investigate the role of retinoid X receptor (RXRα)–Nurr1 heterodimers in tyrosine hydroxylase (TH) expression, we observed retrovirus-induced RXRα–Nurr1 heterodimer interactions with, and transactivation of, the TH promoter region in cultured rat embryonic neural precursor cells. Interestingly, forced expression of RXRα with Nurr1 remarkably reduced Nurr1 activity in TH+ dopaminergic neuron generation and significantly down-regulated TH promoter activity. These regulatory activities were altered in both Nurr1dim- and RXRαdim- that disrupted dimeric binding, verifying that the Nurr1–RXRα heterodimer represses TH promoter activity. Therefore, a plausible explanation for the inhibitory role of RXRα in Nurr1-induced TH expression is that RXRα differentially affects an inhibitory element of the TH promoter.
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Kim Y, Park J, Song WJ, Chang S. Overexpression of Dyrk1A causes the defects in synaptic vesicle endocytosis. Neurosignals 2010; 18:164-72. [PMID: 21135538 DOI: 10.1159/000321994] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 10/12/2010] [Indexed: 11/19/2022] Open
Abstract
Trisomy 21-linked Dyrk1A (dual-specificity tyrosine phosphorylation-regulated kinase 1A) overexpression is implicated in pathogenic mechanisms underlying mental retardation in Down syndrome (DS). It is known to phosphorylate multiple substrates including endocytic proteins in vitro, but the functional consequence of Dyrk1A-mediated phosphorylation on endocytosis has never been investigated. Here, we show that overexpression of Dyrk1A causes defects in clathrin-mediated endocytosis and specifically, in the recruitment of endocytic proteins to clathrin-coated pits in fibroblasts. Synaptic vesicle endocytosis also significantly slowed down as a result of Dyrk1A overexpression in cultured hippocampal neurons. These effects are dependent on Dyrk1A kinase activity. The inhibitory effect of Dyrk1A on synaptic vesicle endocytosis was confirmed in neuronal cultures derived from transgenic mice overexpressing Dyrk1A at levels found in DS. Pharmacological blockade of Dyrk1A with epigallocatechin gallate rescued the endocytic phenotypes found in transgenic neurons. Together, our results suggest that aberrant Dyrk1A-mediated phosphorylation of the endocytic machinery perturbs synaptic vesicle endocytosis, which may contribute to synaptic dysfunctions and cognitive deficits associated with DS.
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Affiliation(s)
- Yoonju Kim
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea
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Shul'gina GI. [Neurophysiological and neurotransmitter mechanisms of behavior inhibition in normal and pathological conditions]. Zh Vyssh Nerv Deiat Im I P Pavlova 2010; 60:643-656. [PMID: 21434400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The data concerning neurophysiological and neurotransmitter mechanisms of two principal kinds of inhibition of behavior is carried out: the inborn genetically determined inhibition and that developed in the course of training. On the basis of the experiments performed by the author and the literature on general neurophysiology the conclusion is made that development of inhibition of behavior during training (i.e. internal inhibition, including "latent inhibition") is determined by the relative strengthening of inhibitory hyperpolarization processes either locally (in a conditioned stimulus analyzer) or globally in the brain cortex and other brain structures during intensification of the inhibitory state (profound inhibition of a reflex and sleep). The main neurotransmitter in development of internal inhibition is gamma-aminobutyric acid. Inhibition of behavior without preliminary training arises either during the action of superstrong stimuli, (exceeding the maximum value inhibition) or during interaction of two and more active systems. A stronger one of these two systems suppresses another one (external inhibition, dominant inhibition, "freezing", "prepulse inhibition", etc.). These kinds of inhibition develop on the background of EEG activation, which suggests participation in their realization of reticular structures and corresponding neurotransmitters (acetylcholine, noradrenalin, dopamine and serotonin). Behavior pathology causes a break of the balanced interaction between the excitation and inhibition in the central nervous system. This affects both genetically determined forms of behavior inhibition and the learned internal inhibition.
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Yoshikawa T, Maekawa M, Ohnishi T, Hashimoto K, Watanabe A. [Analysis of mouse strain-dependent prepulse inhibition points to a role for Shmt1 (SHMT1) in mice and in schizophrenia]. Nihon Shinkei Seishin Yakurigaku Zasshi 2010; 30:197-200. [PMID: 21226315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Deficits in prepulse inhibition (PPI) are thought to be a biological trait of mental illnesses, including schizophrenia. It is known that the N-methyl-D-aspartate type glutamate (NMDA) receptor function affects PPI integrity and D-serine and glycine are typical endogenous co-agonists for the receptor. In parallel, we re-visited our prior quantitative trait loci (QTL) analysis study that examined C57BL/6 (B6) mice with high PPI and C3H/He (C3) with low PPI, and noticed that the genes encoding enzymes responsible for the productions of D-serine (serine racemase: Srr) and glycine (serine hydroxymethyltransferase 1: Shmt1) map to the chromosome 11 QTL. Therefore, we set out to examine whether brain interstitial fluid (ISF) levels of the two amino acids are different between the two mouse strains, using in vivo microdialysis. Recovery of D-serine and glycine from the dialysate of the frontal cortex was higher in B6 mice, which performed better in PPI, compared to C3 mice. Next, we analyzed the two genes, Srr and Shmt1. We then identified promoter polymorphisms in Shmt1 which elicit lower transcriptional activity in B6 compared to C3 mice. Human studies revealed higher expression levels of SHMT1 in the frontal cortex of postmortem brains from schizophrenics compared to controls, but no changes in SRR levels. In addition, genetic analysis detected a nominal association between SHMT1 and schizophrenia. These results suggest that Shmt1 (SHMT1) is one of the genetic components regulating PPI in mice and is relevant to schizophrenia susceptibility in humans.
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Affiliation(s)
- Takeo Yoshikawa
- Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute, Saitama 351-0198, Japan.
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Abstract
In the Drosophila antennal lobe, excitation can spread between glomerular processing channels. In this study, we investigated the mechanism of lateral excitation. Dual recordings from excitatory local neurons (eLNs) and projection neurons (PNs) showed that eLN-to-PN synapses transmit both hyperpolarization and depolarization, are not diminished by blocking chemical neurotransmission, and are abolished by a gap-junction mutation. This mutation eliminates odor-evoked lateral excitation in PNs and diminishes some PN odor responses. This implies that lateral excitation is mediated by electrical synapses from eLNs onto PNs. In addition, eLNs form synapses onto inhibitory LNs. Eliminating these synapses boosts some PN odor responses and reduces the disinhibitory effect of GABA receptor antagonists on PNs. Thus, eLNs have two opposing effects on PNs, driving both direct excitation and indirect inhibition. We propose that when stimuli are weak, lateral excitation promotes sensitivity, whereas when stimuli are strong, lateral excitation helps recruit inhibitory gain control.
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Affiliation(s)
- Emre Yaksi
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
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Hargus NJ, Merrick EC, Nigam A, Kalmar CL, Baheti AR, Bertram EH, Patel MK. Temporal lobe epilepsy induces intrinsic alterations in Na channel gating in layer II medial entorhinal cortex neurons. Neurobiol Dis 2010; 41:361-76. [PMID: 20946956 DOI: 10.1016/j.nbd.2010.10.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Revised: 09/22/2010] [Accepted: 10/04/2010] [Indexed: 11/18/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is the most common form of adult epilepsy involving the limbic structures of the temporal lobe. Layer II neurons of the entorhinal cortex (EC) form the major excitatory input into the hippocampus via the perforant path and consist of non-stellate and stellate neurons. These neurons are spared and hyper-excitable in TLE. The basis for the hyper-excitability is likely multifactorial and may include alterations in intrinsic properties. In a rat model of TLE, medial EC (mEC) non-stellate and stellate neurons had significantly higher action potential (AP) firing frequencies than in control. The increase remained in the presence of synaptic blockers, suggesting intrinsic mechanisms. Since sodium (Na) channels play a critical role in AP generation and conduction we sought to determine if Na channel gating parameters and expression levels were altered in TLE. Na channel currents recorded from isolated mEC TLE neurons revealed increased Na channel conductances, depolarizing shifts in inactivation parameters and larger persistent (I(NaP)) and resurgent (I(NaR)) Na currents. Immunofluorescence experiments revealed increased staining of Na(v)1.6 within the axon initial segment and Na(v)1.2 within the cell bodies of mEC TLE neurons. These studies provide support for additional intrinsic alterations within mEC layer II neurons in TLE and implicate alterations in Na channel activity and expression, in part, for establishing the profound increase in intrinsic membrane excitability of mEC layer II neurons in TLE. These intrinsic changes, together with changes in the synaptic network, could support seizure activity in TLE.
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Affiliation(s)
- Nicholas J Hargus
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22908, USA
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Dickson HM, Zurawski J, Zhang H, Turner DL, Vojtek AB. POSH is an intracellular signal transducer for the axon outgrowth inhibitor Nogo66. J Neurosci 2010; 30:13319-25. [PMID: 20926658 PMCID: PMC2963859 DOI: 10.1523/jneurosci.1324-10.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 07/22/2010] [Accepted: 08/07/2010] [Indexed: 01/31/2023] Open
Abstract
Myelin-derived inhibitors limit axon outgrowth and plasticity during development and in the adult mammalian CNS. Nogo66, a functional domain of the myelin-derived inhibitor NogoA, signals through the PirB receptor to inhibit axon outgrowth. The signaling pathway mobilized by Nogo66 engagement of PirB is not well understood. We identify a critical role for the scaffold protein Plenty of SH3s (POSH) in relaying process outgrowth inhibition downstream of Nogo66 and PirB. Blocking the function of POSH, or two POSH-associated proteins, leucine zipper kinase (LZK) and Shroom3, with RNAi in cortical neurons leads to release from myelin and Nogo66 inhibition. We also observed autocrine inhibition of process outgrowth by NogoA, and suppression analysis with the POSH-associated kinase LZK demonstrated that LZK operates downstream of NogoA and PirB in a POSH-dependent manner. In addition, cerebellar granule neurons with an RNAi-mediated knockdown in POSH function were refractory to the inhibitory action of Nogo66, indicating that a POSH-dependent mechanism operates to inhibit axon outgrowth in different types of CNS neurons. These studies delineate an intracellular signaling pathway for process outgrowth inhibition by Nogo66, comprised of NogoA, PirB, POSH, LZK, and Shroom3, and implicate the POSH complex as a potential therapeutic target to enhance axon outgrowth and plasticity in the injured CNS.
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Affiliation(s)
| | | | - Huanqing Zhang
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - David L. Turner
- Department of Biological Chemistry and
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109
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Piccinin S, Di Angelantonio S, Piccioni A, Volpini R, Cristalli G, Fredholm BB, Limatola C, Eusebi F, Ragozzino D. CX3CL1-induced modulation at CA1 synapses reveals multiple mechanisms of EPSC modulation involving adenosine receptor subtypes. J Neuroimmunol 2010; 224:85-92. [PMID: 20570369 DOI: 10.1016/j.jneuroim.2010.05.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 05/04/2010] [Indexed: 11/18/2022]
Abstract
We characterized the role of adenosine receptor (AR) subtypes in the modulation of glutamatergic neurotransmission by the chemokine fractalkine (CX3CL1) in mouse hippocampal CA1 neurons. CX(3)CL1 causes a reversible depression of excitatory postsynaptic current (EPSC), which is abolished by the A(3)R antagonist MRS1523, but not by A(1)R (DPCPX) or A(2A)R (SCH58261) antagonists. Consistently, CX3CL1-induced EPSC depression is absent in slices from A(3)R(-/-) but not A(1)R(-/-) or A(2A)R(-/-) mice. Further, A(3)R stimulation causes similar EPSC depression. In cultured neurons, CX3CL1-induced depression of AMPA current shows A(1)R-A(3)R pharmacology. We conclude that glutamatergic depression induced by released adenosine requires the stimulation of different ARs.
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MESH Headings
- Adenosine A1 Receptor Antagonists
- Adenosine A2 Receptor Antagonists
- Adenosine A3 Receptor Antagonists
- Animals
- CA1 Region, Hippocampal/immunology
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/ultrastructure
- Cells, Cultured
- Chemokine CX3CL1/physiology
- Excitatory Postsynaptic Potentials/genetics
- Excitatory Postsynaptic Potentials/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neural Inhibition/genetics
- Neural Inhibition/immunology
- Organ Culture Techniques
- Patch-Clamp Techniques
- Presynaptic Terminals/immunology
- Presynaptic Terminals/metabolism
- Receptor, Adenosine A1/deficiency
- Receptor, Adenosine A1/physiology
- Receptor, Adenosine A3/deficiency
- Receptor, Adenosine A3/physiology
- Receptors, Adenosine A2/deficiency
- Receptors, Adenosine A2/physiology
- Receptors, Purinergic P1/deficiency
- Receptors, Purinergic P1/genetics
- Receptors, Purinergic P1/physiology
- Synaptic Transmission/genetics
- Synaptic Transmission/immunology
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Affiliation(s)
- S Piccinin
- Istituto Pasteur-Fondazione Cenci Bolognetti & Dipartimento di Fisiologia e Farmacologia Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Rome, Italy
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Abstract
Schwann cells are attractive candidates for repair of the injured spinal cord. Transplanted Schwann cells are permissive to regeneration, but their ability to promote regeneration into distal spinal cord remains weak despite their production of growth-promoting neurotrophins. Schwann cell activation such as that which accompanies peripheral nerve injury results in massive upregulation of the p75(NTR) pan-neurotrophin-receptor. Here we test the hypothesis that this p75(NTR) upregulation following dorsal root injury limits availability of endogenous neurotrophin to axons and restricts regeneration of injured axons into the spinal cord. We injured dorsal roots (fourth cervical to second thoracic) in mice lacking the neurotrophin-binding domain of p75(NTR) and in wild-type littermates. Axonal regeneration was assessed by selective tracing of neurotrophin-responsive and non-responsive dorsal root ganglion neurons. Functional reinnervation of the spinal cord was assessed in behavioural experiments and via Fos immunohistochemistry following formalin injection into the forepaw. We also measured levels of nerve growth factor and neurotrophin-3 following nerve injury in knockout and wild-type mice, and used Trk-Fc receptor chimeras to block nerve growth factor and neurotrophin-3 signalling in dorsal root ganglion/Schwann cell co-cultures and following dorsal root injury in vivo. The roles of neuronal and glial p75(NTR) were assessed in transplant experiments in vivo and in co-cultures. We found that nerve growth factor and neurotrophin-3-responsive axons regenerated into the spinal cord of p75(NTR) knockout mice where they made functional connections with dorsal horn neurons. Despite equivalent levels of nerve growth factor and neurotrophin-3 in wild-type and knockout mice, successful regeneration in knockouts was neurotrophin-dependent. Transplantation of p75(-/-) neurons into a wild-type environment, p75(-/-) peripheral nerve grafts into the injured p75(+/+) spinal cord, and dissociated sensory neuron/Schwann cell co-cultures showed that the absence of p75(NTR) from glia, not from neurons, promotes regeneration. These findings indicate that Schwann cell p75(NTR) restricts neurotrophin availability to the extent that it prevents spontaneous sensory axon regeneration into the spinal cord. The implication is that inactivating p75(NTR) in Schwann (or olfactory ensheathing) cells may enable axons to grow beyond transplants, improving the outcome of spinal cord injury.
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Abstract
GABA(A) receptors (GABAR) mediate most inhibition in the CNS and are also a target for neuroactive steroids such as 3alpha,5[alpha]beta-THP (3alphaOH-5[alpha]beta-OH-pregnan-20-one or [allo]pregnanolone). Although these steroids robustly enhance current gated by alpha1beta2delta GABAR, we have shown that 3alpha,5[alpha]beta-THP effects at recombinant alpha4beta2delta GABAR depend on the direction of Cl(-) flux, where the steroid increases outward flux, but decreases inward flux through the receptor. This polarity-dependent inhibition of alpha4beta2delta GABAR resulted from an increase in the rate and extent of rapid desensitization of the receptor, recorded from recombinant receptors expressed in HEK-293 cells with whole cell voltage clamp techniques. This inhibitory effect of 3alpha,5[alpha]beta-THP was not observed at other receptor subtypes, suggesting it was selective for alpha4beta2delta GABAR. Furthermore, it was prevented by a selective mutation of basic residue arginine 353 in the intracellular loop of the receptor, suggesting that this might be a putative chloride modulatory site. Expression of alpha4betadelta GABAR increases markedly at extrasynaptic sites at the onset of puberty in female mice. At this time, 3alpha,5[alpha]beta-THP decreased the inhibitory tonic current, recorded with perforated patch techniques to maintain the physiological Cl(-) gradient. By decreasing this shunting inhibition, 3alpha,5[alpha]beta-THP increased the excitability of CA1 hippocampal pyramidal cells at puberty. These effects of the steroid were opposite to those observed before puberty when 3alpha,5[alpha]beta-THP reduced neuronal excitability as a pre-synaptic effect. Behaviorally, the excitatory effect of 3alpha,5[alpha]beta-THP was reflected as an increase in anxiety at the onset of puberty in female mice. Taken together, these findings suggest that the emergence of alpha4beta2delta GABAR at the onset of puberty reverses the effect of a stress steroid. These findings may be relevant for the mood swings and increased response to stressful events reported in adolescence.
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Affiliation(s)
- Sheryl S Smith
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY 11203, USA.
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42
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Münch TA, da Silveira RA, Siegert S, Viney TJ, Awatramani GB, Roska B. Approach sensitivity in the retina processed by a multifunctional neural circuit. Nat Neurosci 2009; 12:1308-16. [PMID: 19734895 DOI: 10.1038/nn.2389] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Accepted: 07/28/2009] [Indexed: 11/09/2022]
Abstract
The detection of approaching objects, such as looming predators, is necessary for survival. Which neurons and circuits mediate this function? We combined genetic labeling of cell types, two-photon microscopy, electrophysiology and theoretical modeling to address this question. We identify an approach-sensitive ganglion cell type in the mouse retina, resolve elements of its afferent neural circuit, and describe how these confer approach sensitivity on the ganglion cell. The circuit's essential building block is a rapid inhibitory pathway: it selectively suppresses responses to non-approaching objects. This rapid inhibitory pathway, which includes AII amacrine cells connected to bipolar cells through electrical synapses, was previously described in the context of night-time vision. In the daytime conditions of our experiments, the same pathway conveys signals in the reverse direction. The dual use of a neural pathway in different physiological conditions illustrates the efficiency with which several functions can be accommodated in a single circuit.
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Affiliation(s)
- Thomas A Münch
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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Quednow BB, Schmechtig A, Ettinger U, Petrovsky N, Collier DA, Vollenweider FX, Wagner M, Kumari V. Sensorimotor gating depends on polymorphisms of the serotonin-2A receptor and catechol-O-methyltransferase, but not on neuregulin-1 Arg38Gln genotype: a replication study. Biol Psychiatry 2009; 66:614-20. [PMID: 19545856 PMCID: PMC3184478 DOI: 10.1016/j.biopsych.2009.05.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 05/12/2009] [Accepted: 05/12/2009] [Indexed: 01/04/2023]
Abstract
BACKGROUND Prepulse inhibition (PPI) of the acoustic startle response (ASR) is an operational measure of sensorimotor gating and a promising endophenotype of schizophrenia. We have recently shown that the linked serotonin-2A receptor (5-HT(2A)R) A-1438 G and T102C polymorphisms modulate PPI in schizophrenia patients. Moreover, it was shown that genetic variation in the catechol-O-methyltransferase (COMT) and the neuregulin-1 (NRG-1) proteins influences PPI in schizophrenia patients and healthy volunteers. Therefore, we aimed to replicate these results and investigated the impact of the related polymorphisms on PPI in healthy human volunteers. METHODS We analyzed the 5-HT(2A)R A-1438 G/T102C (rs6311/rs6313), the COMT Val158Met (rs4680), and the NRG-1 Arg38Gln (rs3924999) polymorphisms, assessing startle reactivity, habituation, and PPI of ASR in 107 healthy Caucasian volunteers. RESULTS Subjects homozygous for the 5-HT(2A)R T102C-T/A-1438 G-A allele showed increased PPI levels. In particular, male subjects with the COMT Met158Met-genotype also showed elevated PPI. The NRG-1 Arg38Gln genotype did not have a significant impact on PPI. Startle reactivity was not affected by any of the investigated polymorphisms. CONCLUSIONS We confirmed in an independent sample of healthy volunteers that PPI is influenced by genetic variation in the 5-HT(2A)R gene. The influence of the COMT Val158Met genotype on PPI appears to be sex-specific. These results underscore the significance of the serotonin and dopamine systems in the modulation of sensorimotor gating.
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Wang YY, Wei YY, Huang J, Wang W, Tamamaki N, Li YQ, Wu SX. Expression patterns of 5-HT receptor subtypes 1A and 2A on GABAergic neurons within the spinal dorsal horn of GAD67-GFP knock-in mice. J Chem Neuroanat 2009; 38:75-81. [PMID: 19409978 DOI: 10.1016/j.jchemneu.2009.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 04/03/2009] [Accepted: 04/24/2009] [Indexed: 11/18/2022]
Abstract
5-HT plays an important role in GABA transmission at the spinal cord level. The main purpose of the present article is to find out, which 5-HT receptor subtypes may be involved in the regulation of GABAergic transmission in the spinal dorsal horn, by using the combination of tissue RT-PCR, single-cell RT-PCR and double immunofluorescent staining on the GAD(67)-GFP knock-in mice. The present result showed that 5-HT(1A) receptor subtype mRNA was present on about half of GFP-positive GABAergic interneurons in the spinal dorsal horn, which suggests a role of 5-HT(1A) receptor in GABA-mediated modulation of nociception at the spinal cord level. However, it is unexpected that just a very limited sub-population of the total GABAergic interneurons express 5-HT(2A) receptor mRNA or proteins in the spinal dorsal horn, which suggests that the 5-HT(2A) receptor subtype may not be important for spinal GABAergic effects in nociceptive modulation.
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MESH Headings
- Animals
- Female
- Fluorescent Antibody Technique
- Gene Expression Regulation/physiology
- Gene Knock-In Techniques
- Glutamate Decarboxylase/genetics
- Green Fluorescent Proteins/genetics
- Interneurons/cytology
- Interneurons/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neural Inhibition/genetics
- Nociceptors/cytology
- Nociceptors/metabolism
- Pain/genetics
- Pain/metabolism
- Pain/physiopathology
- Posterior Horn Cells/cytology
- Posterior Horn Cells/metabolism
- Receptor, Serotonin, 5-HT1A/genetics
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Recombinant Fusion Proteins/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Serotonin/metabolism
- Synaptic Transmission/genetics
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- Ya-Yun Wang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an 710032, People's Republic of China
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Ohgake S, Shimizu E, Hashimoto K, Okamura N, Koike K, Koizumi H, Fujisaki M, Kanahara N, Matsuda S, Sutoh C, Matsuzawa D, Muramatsu H, Muramatsu T, Iyo M. Dopaminergic hypofunctions and prepulse inhibition deficits in mice lacking midkine. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:541-6. [PMID: 19217924 DOI: 10.1016/j.pnpbp.2009.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 02/08/2009] [Accepted: 02/08/2009] [Indexed: 02/04/2023]
Abstract
Midkine is a 13-kDa retinoic acid-induced heparin-binding growth factor involved in various biological phenomena such as cell migration, neurogenesis, and tissue repair. We previously demonstrated that midkine-deficient (Mdk(-/-)) mice exhibited a delayed hippocampal development with impaired working memory and increased anxiety only at the age of 4 weeks. To assess whether midkine gene could play important roles in development and maintenance of central nervous system, we investigated biochemical and behavioral parameters in dopamine and glutamate neurotransmission of Mdk(-/-) mice. The Mdk(-/-) mice exhibited a hypodopaminergic state (i.e., decreased levels of dopamine and its receptors in the striatum) with no alterations of glutamatergic system (i.e., normal level of glutamate, glutamine, glycine, d-serine, l-serine, and NMDA receptors in the frontal cortex and hippocampus). We also found prepulse inhibition deficits reversed by clozapine and haloperidol in the Mdk(-/-) mice. Our results suggested that midkine deficiency may be related to neurochemical and behavioral dysfunctions in dopaminergic system.
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MESH Headings
- Acoustic Stimulation/methods
- Analysis of Variance
- Animals
- Behavior, Animal/drug effects
- Chromatography, High Pressure Liquid/methods
- Cytokines/deficiency
- Dopamine/metabolism
- Dopamine Antagonists/metabolism
- Dopamine Antagonists/pharmacology
- Dopamine Plasma Membrane Transport Proteins/metabolism
- Dose-Response Relationship, Drug
- Exploratory Behavior/physiology
- Interpersonal Relations
- Mice
- Mice, Inbred C57BL/metabolism
- Mice, Inbred DBA/metabolism
- Mice, Knockout
- Midkine
- Motor Activity/drug effects
- Motor Activity/genetics
- Neural Inhibition/drug effects
- Neural Inhibition/genetics
- Protein Binding/drug effects
- Protein Binding/genetics
- Radioligand Assay/methods
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/metabolism
- Reflex, Startle/drug effects
- Reflex, Startle/genetics
- Tritium/metabolism
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Affiliation(s)
- Shintaro Ohgake
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan
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Hong EJ, McCord AE, Greenberg ME. A biological function for the neuronal activity-dependent component of Bdnf transcription in the development of cortical inhibition. Neuron 2009; 60:610-24. [PMID: 19038219 DOI: 10.1016/j.neuron.2008.09.024] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 08/20/2008] [Accepted: 09/12/2008] [Indexed: 12/16/2022]
Abstract
Neuronal activity-regulated gene expression has been suggested to be an important mediator of long-lasting, experience-dependent changes in the nervous system, but the activity-dependent component of gene transcription has never been selectively isolated and tested for its functional significance. Here, we demonstrate that introduction of a subtle knockin mutation into the mouse Bdnf gene that blocks the ability of the activity-regulated factor CREB to bind Bdnf promoter IV results in an animal in which the sensory experience-dependent induction of Bdnf expression is disrupted in the cortex. Neurons from these animals form fewer inhibitory synapses, have fewer spontaneous inhibitory quantal events, and exhibit reduced expression of inhibitory presynaptic markers in the cortex. These results indicate a specific requirement for activity-dependent Bdnf expression in the development of inhibition in the cortex and demonstrate that the activation of gene expression in response to experience-driven neuronal activity has important biological consequences in the nervous system.
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Affiliation(s)
- Elizabeth J Hong
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
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Roussos P, Giakoumaki SG, Rogdaki M, Pavlakis S, Frangou S, Bitsios P. Prepulse inhibition of the startle reflex depends on the catechol O-methyltransferase Val158Met gene polymorphism. Psychol Med 2008; 38:1651-1658. [PMID: 18261249 DOI: 10.1017/s0033291708002912] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Recent evidence suggests that dopamine (DA) agonist-induced disruption of prepulse inhibition (PPI) depends on basal PPI values, in a manner that suggests an inverted U-shaped relationship between PPI and prefrontal DA levels. This is the first study to examine possible genetic determinants of PPI and the catechol O-methyltransferase (COMT) Val158Met polymorphism, the main catabolic pathway of released DA in the prefrontal cortex (PFC). METHOD PPI was measured in 93 healthy males presented with 75-dB and 85-dB prepulses at 60-ms and 120-ms prepulse-pulse intervals. Subjects were grouped according to their COMT status into a Val/Val, a Val/Met and a Met/Met group. RESULTS ANOVAs showed that at all prepulse and interval conditions, Val/Val individuals had the lowest PPI, Met/Met the highest, and Val/Met were intermediate. CONCLUSIONS These results suggest that PPI is regulated by DA neurotransmission in the PFC and its levels depend on the COMT Val158Met gene polymorphism. These findings enhance the value of the PPI paradigm in examining individual variability of early information processing in healthy subjects and psychiatric disorders associated with changes in PFC DA activity and attentional deficits such as schizophrenia.
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Affiliation(s)
- P Roussos
- Department of Psychiatry and Behavioural Sciences, University of Crete, Heraklion, Crete, Greece
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Spampanato J, Gu X, Yang XW, Mody I. Progressive synaptic pathology of motor cortical neurons in a BAC transgenic mouse model of Huntington's disease. Neuroscience 2008; 157:606-20. [PMID: 18854207 DOI: 10.1016/j.neuroscience.2008.09.020] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 08/27/2008] [Accepted: 09/13/2008] [Indexed: 11/19/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a polyglutamine repeat expansion in huntingtin. A newly developed bacterial artificial chromosome transgenic mouse model (BACHD) reproduces phenotypic features of HD including predominantly neuropil-associated protein aggregation and progressive motor dysfunction with selective neurodegenerative pathology. Motor dysfunction has been shown to precede neuropathology in BACHD mice. We therefore investigated the progression of synaptic pathology in pyramidal cells and interneurons of the superficial motor cortex of BACHD mice. Whole-cell patch clamp recordings were performed on layer 2/3 primary motor cortical pyramidal cells and parvalbumin interneurons from BACHD mice at 3 months, when the mice begin to demonstrate mild motor dysfunction, and at 6 months, when the motor dysfunction is more severe. Changes in synaptic variances were detectable at 3 months, and at 6 months BACHD mice display progressive synaptic pathology in the form of reduced cortical excitation and loss of inhibition onto pyramidal cells. These results suggest that progressive alterations of the superficial cortical circuitry may contribute to the decline of motor function in BACHD mice. The synaptic pathology occurs prior to neuronal degeneration and may therefore prove useful as a target for future therapeutic design.
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Affiliation(s)
- J Spampanato
- Department of Neurology, David Geffen School of Medicine, University of California, NRB1 Room 575D, 635 Charles E. Young Drive South, Los Angeles, CA 90095-7335, USA
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Kharlamov EA, Downey KL, Jukkola PI, Grayson DR, Kelly KM. Expression of GABA A receptor alpha1 subunit mRNA and protein in rat neocortex following photothrombotic infarction. Brain Res 2008; 1210:29-38. [PMID: 18407248 PMCID: PMC2587253 DOI: 10.1016/j.brainres.2008.02.070] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 01/29/2008] [Accepted: 02/18/2008] [Indexed: 11/20/2022]
Abstract
Photothrombotic infarcts of the neocortex result in structural and functional alterations of cortical networks, including decreased GABAergic inhibition, and can generate epileptic seizures within 1 month of lesioning. In our study, we assessed the involvement and potential changes of cortical GABA A receptor (GABA AR) alpha1 subunits at 1, 3, 7, and 30 days after photothrombosis. Quantitative competitive reverse transcription-polymerase chain reaction (cRT-PCR) and semi-quantitative Western blot analysis were used to investigate GABA AR alpha1 subunit mRNA and protein levels in proximal and distal regions of perilesional cortex and in homotopic areas of young adult Sprague-Dawley rats. GABA AR alpha1 subunit mRNA levels were decreased ipsilateral and contralateral to the infarct at 7 days, but were increased bilaterally at 30 days. GABA AR alpha1 subunit protein levels revealed no significant change in neocortical areas of both hemispheres of lesioned animals compared with protein levels of sham-operated controls at 1, 3, 7, and 30 days. At 30 days, GABA AR alpha1 subunit protein expression was significantly increased in lesioned animals within proximal and distal regions of perilesional cortex compared with distal neocortical areas contralaterally (Student's t-test, p<0.05). Short- and long-term alterations of mRNA and protein levels of the GABA AR alpha1 subunit ipsilateral and contralateral to the lesion may influence alterations in cell surface receptor subtype expression and GABA AR function following ischemic infarction and may be associated with formative mechanisms of poststroke epileptogenesis.
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Affiliation(s)
- Elena A Kharlamov
- Department of Neurology, Center for Neuroscience Research, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA, USA
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Vergnano AM, Ferrini F, Salio C, Lossi L, Baratta M, Merighi A. The gastrointestinal hormone ghrelin modulates inhibitory neurotransmission in deep laminae of mouse spinal cord dorsal horn. Endocrinology 2008; 149:2306-12. [PMID: 18202139 DOI: 10.1210/en.2007-1164] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin is mainly described for its effects on feeding behavior and metabolism. However, central nervous system distribution of its receptor [type 1a GH secretagogue receptor (GHSR)] and modulation of neurotransmission in the hypothalamus suggest broader effects than originally predicted. Systemically administrated ghrelin inhibits inflammatory pain after behavioral observations. Therefore, we investigated the expression and function of type 1a GHSR in mouse spinal cord by molecular biology, biochemistry, histology, and electrophysiology. The mRNA and protein were detected in tissue extracts by RT-PCR and Western blotting. In situ, receptor mRNA and immunoreactivity were localized to cell bodies within the medial aspect of the deep dorsal horn. Patch clamp recordings on laminae IV-VI demonstrated that bath-applied ghrelin (100 nm) induced a strong increase of spontaneous gamma-aminobutyric acid/glycine-mediated current frequency (463 +/- 93% of the control) and amplitude (150 +/- 16% of the control) in about 60% of recorded neurons. Specificity of type 1a GHSR activation was confirmed by the lack of effect of the deacylated form of ghrelin (des-acyl-ghrelin) and after preincubation with the specific receptor antagonist [d-Lys(3)]GHRP-6. In the presence of tetrodotoxin, the effect of the peptide was strongly reduced, mainly indicating an action potential-dependent mechanism. The functional link between ghrelin and pain was confirmed by inhibition in vitro of the c-fos response to capsaicin activation of nociceptive fibers, after quantification of Fos-immunoreactive nuclei in laminae IV-VI. Our results are the first demonstration of the presence of functional type 1a GHSRs in the spinal cord and indicate that ghrelin may exert antinociceptive effects by directly increasing inhibitory neurotransmission in a subset of deep dorsal horn neurons.
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Affiliation(s)
- Angela M Vergnano
- Department of Veterinary Morphophysiology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Torino), Italy
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