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Assareh N, Fenech C, Power R, Uddin MN, Otsu Y, Aubrey KR. Bidirectional modulation of nociception by GlyT2 + neurons in the ventrolateral periaqueductal gray. eNeuro 2023:ENEURO.0069-23.2023. [PMID: 37253591 DOI: 10.1523/eneuro.0069-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 06/01/2023] Open
Abstract
The midbrain periaqueductal gray (PAG), particularly its ventrolateral column (vlPAG), is part of a key descending pathway that modulates nociception, fear and anxiety behaviours in both humans and rodents. It has been previously demonstrated that inhibitory GABAergic neurons within the vlPAG have a major role in this nociceptive modulation. However, the PAG contains a diverse range of neuronal subtypes and the contribution of different subtypes of inhibitory neurons to nociceptive control has not been investigated. Here, we employed a chemogenetic strategy in mice that express Cre- under the promotor for the glycine transporter 2 (GlyT2::cre) to modulate a novel group of glycinergic neurons within the vlPAG and then investigate their role in nociceptive control. We show that activation of GlyT2-PAG neurons enhances cold and noxious heat responses and increases locomotor activity in both male and female mice. In contrast, inhibition of GlyT2-PAG neurons reduced nociceptive responses, while locomotor behaviours were unaffected. Our findings demonstrate that GlyT2+ neurons in the vlPAG modulate nociception and suggest that strategies targeting GlyT2-PAG neurons could be used to design novel analgesic therapies.Summary statementNeuronal circuits are composed of diverse collections of cell types, each with a distinct set of synaptic connections that determine their role in specific functions. One challenge in neuropharmacology is to design drugs that interact with the brain circuits required to have the desired therapeutic effect and limit their activity at nearby circuits, thus reducing side effects. The current study shows that a genetically identified subpopulation of GlyT2+ neurons that are concentrated in the vlPAG can bidirectionally modulate nociceptive responses and alter locomotion behaviours in mice. These findings provided novel insights into the organization of the nociceptive circuitry of the PAG and identify GlyT2-PAG neurons as a potential target for analgesic drug design.
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Affiliation(s)
- Neda Assareh
- Pain Management Research, Kolling Institute, Royal North Shore Hospital NSLHD and Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
- Sydney Pain Consortium, Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
| | - Caitlin Fenech
- Pain Management Research, Kolling Institute, Royal North Shore Hospital NSLHD and Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
- Sydney Pain Consortium, Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
| | - Rebecca Power
- Pain Management Research, Kolling Institute, Royal North Shore Hospital NSLHD and Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
- Sydney Pain Consortium, Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
| | - Mohammad N Uddin
- Pain Management Research, Kolling Institute, Royal North Shore Hospital NSLHD and Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
| | - Yo Otsu
- Pain Management Research, Kolling Institute, Royal North Shore Hospital NSLHD and Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
- Sydney Pain Consortium, Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
| | - Karin R Aubrey
- Pain Management Research, Kolling Institute, Royal North Shore Hospital NSLHD and Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
- Sydney Pain Consortium, Faculty of Medicine and Health, University of Sydney, Sydney NSW Australia
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2
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Otsu Y, Aubrey KR. Kappa opioids inhibit the GABA/glycine terminals of rostral ventromedial medulla projections in the superficial dorsal horn of the spinal cord. J Physiol 2022; 600:4187-4205. [PMID: 35979937 PMCID: PMC9540474 DOI: 10.1113/jp283021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 07/22/2022] [Indexed: 11/08/2022] Open
Abstract
Descending projections from neurons in the rostral ventromedial medulla (RVM) make synapses within the superficial dorsal horn (SDH) of the spinal cord that are involved in the modulation of nociception, the development of chronic pain and itch, and an important analgesic target for opioids. This projection is primarily inhibitory, but the relative contribution of GABAergic and glycinergic transmission is unknown and there is limited knowledge about the SDH neurons targeted. Additionally, the details of how spinal opioids mediate analgesia remain unclear, and no study has investigated the opioid modulation of this synapse. We address this using ex vivo optogenetic stimulation of RVM fibres in conjunction with whole-cell patch-clamp recordings from the SDH in spinal cord slices. We demonstrate that both GABAergic and glycinergic neurotransmission is employed and show that SDH target neurons have diverse morphological and electrical properties, consistent with both inhibitory and excitatory interneurons. Then, we describe a subtype of SDH neurons that have a glycine-dominant input, indicating that the quality of descending inhibition across cells is not uniform. Finally, we discovered that the kappa-opioid receptor agonist U69593 presynaptically suppressed most RVM-SDH synapses. By contrast, the mu-opioid receptor agonist DAMGO acted both pre- and post-synaptically at a subset of synapses, and the delta-opioid receptor agonist deltorphin II had little effect. These data provide important mechanistic information about a descending control pathway that regulates spinal circuits. This information is necessary to understand how sensory inputs are shaped and develop more reliable and effective alternatives to current opioid analgesics. Abstract figure legend We combined ex vivo optogenetic stimulation of RVM fibres with whole cell electrophysiology of SDH neurons to investigate the final synapse in a key descending pain modulatory pathway. We demonstrate that both glycine and GABA mediate signalling at the RVM-SDH synapse, that the SDH targets of RVM projections have diverse electrical and morphological characteristics, and that presynaptic inhibition is directly and consistently achieved by kappa opioid agonists. Opioid receptors shown are sized relative to the proportion of neurons that responded to its specific agonists (81 and 84percent of DF and non-DF neurons responded to kappa opioid receptor agonists, respectively. Responses that occurred in <255 percentage of neurons are not indicated here). This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yo Otsu
- Pain Management Research, Kolling Institute at the Royal North Shore Hospital NSLHD, St Leonard, NSW, 2065, Australia.,Faculty of Medicine and Health, Sydney Pain Consortium, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Karin R Aubrey
- Pain Management Research, Kolling Institute at the Royal North Shore Hospital NSLHD, St Leonard, NSW, 2065, Australia.,Faculty of Medicine and Health, Sydney Pain Consortium, University of Sydney, Camperdown, NSW, 2006, Australia
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3
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Aubrey KR, Sheipouri D, Balle T, Vandenberg RJ, Otsu Y. Glutamate, d-(-)-2-Amino-5-Phosphonopentanoic Acid, and N-Methyl-d-Aspartate Do Not Directly Modulate Glycine Receptors. Mol Pharmacol 2020; 98:719-729. [PMID: 33051383 DOI: 10.1124/molpharm.120.000127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/03/2020] [Indexed: 11/22/2022] Open
Abstract
Replication studies play an essential role in corroborating research findings and ensuring that subsequent experimental works are interpreted correctly. A previously published paper indicated that the neurotransmitter glutamate, along with the compounds N-methyl-d-aspartate (NMDA) and d-(-)-2-amino-5-phosphonopentanoic acid (AP5), acts as positive allosteric modulators of inhibitory glycine receptors. The paper further suggested that this form of modulation would play a role in setting the spinal inhibitory tone and influencing sensory signaling, as spillover of glutamate onto nearby glycinergic synapses would permit rapid crosstalk between excitatory and inhibitory synapses. Here, we attempted to replicate this finding in primary cultured spinal cord neurons, spinal cord slice, and Xenopus laevis oocytes expressing recombinant human glycine receptors. Despite extensive efforts, we were unable to reproduce the finding that glutamate, AP5, and NMDA positively modulate glycine receptor currents. We paid careful attention to critical aspects of the original study design and took into account receptor saturation and protocol deviations such as animal species. Finally, we explored possible explanations for the experimental discrepancy. We found that solution contamination with a high-affinity modulator such as zinc is most likely to account for the error, and we suggest methods for preventing this kind of misinterpretation in future studies aimed at characterizing high-affinity modulators of the glycine receptor. SIGNIFICANCE STATEMENT: A previous study indicates that glutamate spillover onto inhibitory synapses can directly interact with glycine receptors to enhance inhibitory signalling. This finding has important implications for baseline spinal transmission and may play a role when chronic pain develops. However, we failed to replicate the results and did not observe glutamate, d-(-)-2-amino-5-phosphonopentanoic acid, or N-methyl-d-aspartate modulation of native or recombinant glycine receptors. We ruled out various sources for the discrepancy and found that the most likely cause is solution contamination.
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Affiliation(s)
- Karin R Aubrey
- Pain Management Research Institute (K.R.A., Y.O.), Kolling Institute of Medical Research, Royal North Shore Hospital and Northern Clinical School, Faculty of Medicine and Health (K.R.A., Y.O.), Pharmacology, Faculty of Medicine and Health (D.S., R.J.V.), Sydney Pharmacy School, Faculty of Medicine and Health (T.B.), and Brain and Mind Centre (T.B.), The University of Sydney, Sydney, Australia
| | - Diba Sheipouri
- Pain Management Research Institute (K.R.A., Y.O.), Kolling Institute of Medical Research, Royal North Shore Hospital and Northern Clinical School, Faculty of Medicine and Health (K.R.A., Y.O.), Pharmacology, Faculty of Medicine and Health (D.S., R.J.V.), Sydney Pharmacy School, Faculty of Medicine and Health (T.B.), and Brain and Mind Centre (T.B.), The University of Sydney, Sydney, Australia
| | - Thomas Balle
- Pain Management Research Institute (K.R.A., Y.O.), Kolling Institute of Medical Research, Royal North Shore Hospital and Northern Clinical School, Faculty of Medicine and Health (K.R.A., Y.O.), Pharmacology, Faculty of Medicine and Health (D.S., R.J.V.), Sydney Pharmacy School, Faculty of Medicine and Health (T.B.), and Brain and Mind Centre (T.B.), The University of Sydney, Sydney, Australia
| | - Robert J Vandenberg
- Pain Management Research Institute (K.R.A., Y.O.), Kolling Institute of Medical Research, Royal North Shore Hospital and Northern Clinical School, Faculty of Medicine and Health (K.R.A., Y.O.), Pharmacology, Faculty of Medicine and Health (D.S., R.J.V.), Sydney Pharmacy School, Faculty of Medicine and Health (T.B.), and Brain and Mind Centre (T.B.), The University of Sydney, Sydney, Australia
| | - Yo Otsu
- Pain Management Research Institute (K.R.A., Y.O.), Kolling Institute of Medical Research, Royal North Shore Hospital and Northern Clinical School, Faculty of Medicine and Health (K.R.A., Y.O.), Pharmacology, Faculty of Medicine and Health (D.S., R.J.V.), Sydney Pharmacy School, Faculty of Medicine and Health (T.B.), and Brain and Mind Centre (T.B.), The University of Sydney, Sydney, Australia
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Otsu Y, Darcq E, Pietrajtis K, Mátyás F, Schwartz E, Bessaih T, Abi Gerges S, Rousseau CV, Grand T, Dieudonné S, Paoletti P, Acsády L, Agulhon C, Kieffer BL, Diana MA. Control of aversion by glycine-gated GluN1/GluN3A NMDA receptors in the adult medial habenula. Science 2020; 366:250-254. [PMID: 31601771 DOI: 10.1126/science.aax1522] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/17/2019] [Indexed: 01/05/2023]
Abstract
The unconventional N-methyl-d-aspartate (NMDA) receptor subunits GluN3A and GluN3B can, when associated with the other glycine-binding subunit GluN1, generate excitatory conductances purely activated by glycine. However, functional GluN1/GluN3 receptors have not been identified in native adult tissues. We discovered that GluN1/GluN3A receptors are operational in neurons of the mouse adult medial habenula (MHb), an epithalamic area controlling aversive physiological states. In the absence of glycinergic neuronal specializations in the MHb, glial cells tuned neuronal activity via GluN1/GluN3A receptors. Reducing GluN1/GluN3A receptor levels in the MHb prevented place-aversion conditioning. Our study extends the physiological and behavioral implications of glycine by demonstrating its control of negatively valued emotional associations via excitatory glycinergic NMDA receptors.
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Affiliation(s)
- Y Otsu
- Institut de Biologie de l'École Normale Supérieure (IBENS), INSERM U1024, CNRS UMR8197, École Normale Supérieure, Université PSL, 75005 Paris, France
| | - E Darcq
- Department of Psychiatry, School of Medicine, Douglas Hospital Research Center, McGill University, Montreal, QC H4H 1R3, Canada
| | - K Pietrajtis
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 75005 Paris, France
| | - F Mátyás
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary.,Research Centre for Natural Sciences Institute of Cognitive Neuroscience and Psychology, 1117 Budapest, Hungary.,Department of Anatomy and Histology, University of Veterinary Medicine, 1078 Budapest, Hungary
| | - E Schwartz
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 75005 Paris, France
| | - T Bessaih
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 75005 Paris, France
| | - S Abi Gerges
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 75005 Paris, France
| | - C V Rousseau
- Institut de Biologie de l'École Normale Supérieure (IBENS), INSERM U1024, CNRS UMR8197, École Normale Supérieure, Université PSL, 75005 Paris, France
| | - T Grand
- Institut de Biologie de l'École Normale Supérieure (IBENS), INSERM U1024, CNRS UMR8197, École Normale Supérieure, Université PSL, 75005 Paris, France
| | - S Dieudonné
- Institut de Biologie de l'École Normale Supérieure (IBENS), INSERM U1024, CNRS UMR8197, École Normale Supérieure, Université PSL, 75005 Paris, France
| | - P Paoletti
- Institut de Biologie de l'École Normale Supérieure (IBENS), INSERM U1024, CNRS UMR8197, École Normale Supérieure, Université PSL, 75005 Paris, France
| | - L Acsády
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary
| | - C Agulhon
- Integrative Neuroscience and Cognition Center, CNRS UMR8002, Glia-Glia and Glia-Neuron Interactions Group, Paris Descartes University, 75006 Paris, France
| | - B L Kieffer
- Department of Psychiatry, School of Medicine, Douglas Hospital Research Center, McGill University, Montreal, QC H4H 1R3, Canada
| | - M A Diana
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 75005 Paris, France.
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5
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Otsu Y, Donneger F, Schwartz EJ, Poncer JC. Cation-chloride cotransporters and the polarity of GABA signalling in mouse hippocampal parvalbumin interneurons. J Physiol 2020; 598:1865-1880. [PMID: 32012273 DOI: 10.1113/jp279221] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/13/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Cation-chloride cotransporters (CCCs) play a critical role in controlling the efficacy and polarity of GABAA receptor (GABAA R)-mediated transmission in the brain, yet their expression and function in GABAergic interneurons has been overlooked. We compared the polarity of GABA signalling and the function of CCCs in mouse hippocampal pyramidal neurons and parvalbumin-expressing interneurons. Under resting conditions, GABAA R activation was mostly depolarizing and yet inhibitory in both cell types. KCC2 blockade further depolarized the reversal potential of GABAA R-mediated currents often above action potential threshold. However, during repetitive GABAA R activation, the postsynaptic response declined independently of the ion flux direction or KCC2 function, suggesting intracellular chloride build-up is not responsible for this form of plasticity. Our data demonstrate similar mechanisms of chloride regulation in mouse hippocampal pyramidal neurons and parvalbumin interneurons. ABSTRACT Transmembrane chloride gradients govern the efficacy and polarity of GABA signalling in neurons and are usually maintained by the activity of cation-chloride cotransporters, such as KCC2 and NKCC1. Whereas their role is well established in cortical principal neurons, it remains poorly documented in GABAergic interneurons. We used complementary electrophysiological approaches to compare the effects of GABAA receptor (GABAA R) activation in adult mouse hippocampal parvalbumin interneurons (PV-INs) and pyramidal cells (PCs). Loose cell-attached, tight-seal and gramicidin-perforated patch recordings all show GABAA R-mediated transmission is slightly depolarizing and yet inhibitory in both PV-INs and PCs. Focal GABA uncaging in whole-cell recordings reveal that KCC2 and NKCC1 are functional in both PV-INs and PCs but differentially contribute to transmembrane chloride gradients in their soma and dendrites. Blocking KCC2 function depolarizes the reversal potential of GABAA R-mediated currents in PV-INs and PCs, often beyond firing threshold, showing KCC2 is essential to maintain the inhibitory effect of GABAA Rs. Finally, we show that repetitive 10 Hz activation of GABAA Rs in both PV-INs and PCs leads to a progressive decline of the postsynaptic response independently of the ion flux direction or KCC2 function. This suggests intraneuronal chloride build-up may not predominantly contribute to activity-dependent plasticity of GABAergic synapses in this frequency range. Altogether our data demonstrate similar mechanisms of chloride regulation in mouse hippocampal PV-INs and PCs and suggest KCC2 downregulation in the pathology may affect the valence of GABA signalling in both cell types.
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Affiliation(s)
- Yo Otsu
- Inserm UMR-S 1270, 75005, Paris, France.,Sorbonne Université, F75005, Paris, France.,Institut du Fer à Moulin, F75005, Paris, France
| | - Florian Donneger
- Inserm UMR-S 1270, 75005, Paris, France.,Sorbonne Université, F75005, Paris, France.,Institut du Fer à Moulin, F75005, Paris, France
| | - Eric J Schwartz
- Inserm UMR-S 1270, 75005, Paris, France.,Sorbonne Université, F75005, Paris, France.,Institut du Fer à Moulin, F75005, Paris, France
| | - Jean Christophe Poncer
- Inserm UMR-S 1270, 75005, Paris, France.,Sorbonne Université, F75005, Paris, France.,Institut du Fer à Moulin, F75005, Paris, France
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Otsu Y, Lecca S, Pietrajtis K, Rousseau CV, Marcaggi P, Dugué GP, Mailhes-Hamon C, Mameli M, Diana MA. Functional Principles of Posterior Septal Inputs to the Medial Habenula. Cell Rep 2019; 22:693-705. [PMID: 29346767 PMCID: PMC5792424 DOI: 10.1016/j.celrep.2017.12.064] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 09/26/2017] [Accepted: 12/20/2017] [Indexed: 11/29/2022] Open
Abstract
The medial habenula (MHb) is an epithalamic hub contributing to expression and extinction of aversive states by bridging forebrain areas and midbrain monoaminergic centers. Although contradictory information exists regarding their synaptic properties, the physiology of the excitatory inputs to the MHb from the posterior septum remains elusive. Here, combining optogenetics-based mapping with ex vivo and in vivo physiology, we examine the synaptic properties of posterior septal afferents to the MHb and how they influence behavior. We demonstrate that MHb cells receive sparse inputs producing purely glutamatergic responses via calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), heterotrimeric GluN2A-GluN2B-GluN1 N-methyl-D-aspartate (NMDA) receptors, and inhibitory group II metabotropic glutamate receptors. We describe the complex integration dynamics of these components by MHb cells. Finally, we combine ex vivo data with realistic afferent firing patterns recorded in vivo to demonstrate that efficient optogenetic septal stimulation in the MHb induces anxiolysis and promotes locomotion, contributing long-awaited evidence in favor of the importance of this septo-habenular pathway. Medial habenular (MHb) neurons receive sparse inputs from the posterior septum (PS) PS afferents to the MHb function in a purely glutamatergic mode Excitatory ionotropic and inhibitory metabotropic receptors convey PS inputs in the MHb PS activation in the MHb increases locomotion and induces anxiolysis
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Affiliation(s)
- Yo Otsu
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Salvatore Lecca
- Institut du Fer à Moulin, INSERM-UPMC UMR-S 839, Paris, France
| | - Katarzyna Pietrajtis
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Charly Vincent Rousseau
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Païkan Marcaggi
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Guillaume Pierre Dugué
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Caroline Mailhes-Hamon
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Manuel Mameli
- Institut du Fer à Moulin, INSERM-UPMC UMR-S 839, Paris, France
| | - Marco Alberto Diana
- Institut de Biologie de l'École Normale Supérieure, INSERM U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France.
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Otsu Y, Marcaggi P, Feltz A, Isope P, Kollo M, Nusser Z, Mathieu B, Kano M, Tsujita M, Sakimura K, Dieudonné S. Activity-dependent gating of calcium spikes by A-type K+ channels controls climbing fiber signaling in Purkinje cell dendrites. Neuron 2014; 84:137-151. [PMID: 25220810 PMCID: PMC4183427 DOI: 10.1016/j.neuron.2014.08.035] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2014] [Indexed: 12/01/2022]
Abstract
In cerebellar Purkinje cell dendrites, heterosynaptic calcium signaling induced by the proximal climbing fiber (CF) input controls plasticity at distal parallel fiber (PF) synapses. The substrate and regulation of this long-range dendritic calcium signaling are poorly understood. Using high-speed calcium imaging, we examine the role of active dendritic conductances. Under basal conditions, CF stimulation evokes T-type calcium signaling displaying sharp proximodistal decrement. Combined mGluR1 receptor activation and depolarization, two activity-dependent signals, unlock P/Q calcium spikes initiation and propagation, mediating efficient CF signaling at distal sites. These spikes are initiated in proximal smooth dendrites, independently from somatic sodium action potentials, and evoke high-frequency bursts of all-or-none fast-rising calcium transients in PF spines. Gradual calcium spike burst unlocking arises from increasing inactivation of mGluR1-modulated low-threshold A-type potassium channels located in distal dendrites. Evidence for graded activity-dependent CF calcium signaling at PF synapses refines current views on cerebellar supervised learning rules.
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Affiliation(s)
- Yo Otsu
- Inhibitory Transmission Team, IBENS, CNRS UMR UMR8197, INSERM U1024, Ecole Normale Supérieure, 75005 Paris, France
| | - Païkan Marcaggi
- Inhibitory Transmission Team, IBENS, CNRS UMR UMR8197, INSERM U1024, Ecole Normale Supérieure, 75005 Paris, France
| | - Anne Feltz
- Cerebellum Group, IBENS, CNRS UMR UMR8197, INSERM U1024, Ecole Normale Supérieure, 75005 Paris, France
| | - Philippe Isope
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212, 67000-Strasbourg, France
| | - Mihaly Kollo
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, 1083 Budapest, Hungary
| | - Zoltan Nusser
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, 1083 Budapest, Hungary
| | - Benjamin Mathieu
- Imaging Facility, IBENS, CNRS UMR 8197, INSERM U1024, Ecole Normale Supérieure, 75005 Paris, France
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Mika Tsujita
- Center for Transdisciplinary Research, Niigata University, Niigata 950-2181, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Stéphane Dieudonné
- Inhibitory Transmission Team, IBENS, CNRS UMR UMR8197, INSERM U1024, Ecole Normale Supérieure, 75005 Paris, France.
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Kawarasaki T, Enya S, Otsu Y. The effect of estrogen administration during early pregnancy upon the survival of single implanted pig embryos. J Anim Sci 2012; 90:4781-7. [DOI: 10.2527/jas.2012-5178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T. Kawarasaki
- Swine and Poultry Research Center, Shizuoka Prefectural Research Institute of Animal Industry, Kikugawa, Shizuoka, 439-0037, Japan
- School of Agriculture, Tokai University, Minamiaso, Kumamoto, 869-1404, Japan
| | - S. Enya
- Swine and Poultry Research Center, Shizuoka Prefectural Research Institute of Animal Industry, Kikugawa, Shizuoka, 439-0037, Japan
| | - Y. Otsu
- Swine and Poultry Research Center, Shizuoka Prefectural Research Institute of Animal Industry, Kikugawa, Shizuoka, 439-0037, Japan
- Shizuoka Prefectural Tobu Livestock Hygiene Service Center, Kannami, Shizuoka 419-0114, Japan
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Otsu Y, Bormuth V, Wong J, Mathieu B, Dugué GP, Feltz A, Dieudonné S. Optical monitoring of neuronal activity at high frame rate with a digital random-access multiphoton (RAMP) microscope. J Neurosci Methods 2008; 173:259-70. [PMID: 18634822 DOI: 10.1016/j.jneumeth.2008.06.015] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 06/10/2008] [Accepted: 06/16/2008] [Indexed: 01/15/2023]
Abstract
Two-photon microscopy offers the promise of monitoring brain activity at multiple locations within intact tissue. However, serial sampling of voxels has been difficult to reconcile with millisecond timescales characteristic of neuronal activity. This is due to the conflicting constraints of scanning speed and signal amplitude. The recent use of acousto-optic deflector scanning to implement random-access multiphoton microscopy (RAMP) potentially allows to preserve long illumination dwell times while sampling multiple points-of-interest at high rates. However, the real-life abilities of RAMP microscopy regarding sensitivity and phototoxicity issues, which have so far impeded prolonged optical recordings at high frame rates, have not been assessed. Here, we describe the design, implementation and characterisation of an optimised RAMP microscope. We demonstrate the application of the microscope by monitoring calcium transients in Purkinje cells and cortical pyramidal cell dendrites and spines. We quantify the illumination constraints imposed by phototoxicity and show that stable continuous high-rate recordings can be obtained. During these recordings the fluorescence signal is large enough to detect spikes with a temporal resolution limited only by the calcium dye dynamics, improving upon previous techniques by at least an order of magnitude.
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Affiliation(s)
- Yo Otsu
- Laboratoire de Neurobiologie, CNRS UMR 8544, Ecole Normale Supérieure, 46 rue d'Ulm 75005, Paris, France
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10
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Liu Z, Otsu Y, Vasuta C, Nawa H, Murphy TH. Action-potential-independent GABAergic tone mediated by nicotinic stimulation of immature striatal miniature synaptic transmission. J Neurophysiol 2007; 98:581-93. [PMID: 17553945 DOI: 10.1152/jn.00768.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stimulation of presynaptic nicotinic acetylcholine receptors (nAChRs) increases the frequency of miniature excitatory synaptic activity (mEPSCs) to a point where they can promote cell firing in hippocampal CA3 neurons. We have evaluated whether nicotine regulation of miniature synaptic activity can be extended to inhibitory transmission onto striatal medium spiny projection neurons (MSNs) in acute brain slices. Bath application of micromolar nicotine typically induced 12-fold increases in the frequency of miniature inhibitory synaptic currents (mIPSCs). Little effect was observed on the amplitude of mIPSCs or mEPSCs under these conditions. Nicotine stimulation of mIPSCs was dependent on entry of extracellular calcium because removal of calcium from perfusate was able to block its action. To assess the potential physiological significance of the nicotine-stimulated increase in mIPSC frequency, we also examined the nicotine effect on evoked IPSCs (eIPSCs). eIPSCs were markedly attenuated by nicotine. This effect could be attributed to two potential mechanisms: transmitter depletion due to extremely high mIPSC rates and/or a reduction in presynaptic excitability associated with nicotinic depolarization. Treatment with low concentrations of K(+) was able to in part mimic nicotine's stimulatory effect on mIPSCs and inhibitory effect on eIPSCs. Current-clamp recordings confirmed a direct depolarizing action of nicotine that could dampen eIPSC activity leading to a switch to striatal inhibitory synaptic transmission mediated by tonic mIPSCs.
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Affiliation(s)
- Zhi Liu
- Kinsmen Laboratory and Brain Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
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11
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Diana MA, Otsu Y, Maton G, Collin T, Chat M, Dieudonné S. T-type and L-type Ca2+ conductances define and encode the bimodal firing pattern of vestibulocerebellar unipolar brush cells. J Neurosci 2007; 27:3823-38. [PMID: 17409247 PMCID: PMC6672410 DOI: 10.1523/jneurosci.4719-06.2007] [Citation(s) in RCA: 45] [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] [Indexed: 11/21/2022] Open
Abstract
Cerebellar unipolar brush cells (UBCs) are glutamatergic interneurons that receive direct input from vestibular afferents in the form of a unique excitatory synapse on their dendritic brush. UBCs constitute independent relay lines for vestibular signals, and their inherent properties most likely determine how vestibular activity is encoded by the cerebellar cortex. We now demonstrate that UBCs are bimodal cells; they can either fire high-frequency bursts of action potentials when stimulated from hyperpolarized potentials or discharge tonically during sustained depolarizations. The two functional states can be triggered by physiological-like activity of the excitatory input and are encoded by distinct Ca2+-signaling systems. By combining complementary strategies, consisting of molecular and electrophysiological analysis and of ultrafast acousto-optical deflector-based two-photon imaging, we unraveled the identity and the subcellular localization of the Ca2+ conductances activating in each mode. Fast inactivating T-type Ca2+ channels produce low-threshold spikes, which trigger the high-frequency bursts and generate powerful Ca2+ transients in the brush and, to a much lesser extent, in the soma. The tonic firing mode is encoded by a signalization system principally composed of L-type channels. Ca2+ influx during tonic firing produces a linear representation of the spike rate of the cell in the form of a widespread and sustained Ca2+ concentration increase and regulates cellular excitability via BK potassium channels. The bimodal firing pattern of UBCs may underlie different coding strategies of the vestibular input by the cerebellum, thus likely increasing the computational power of this structure.
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Affiliation(s)
- Marco A Diana
- Laboratoire de Neurobiologie, Centre National de la Recherche Scientifique Unité Mixte de Recherche 8544, Ecole Normale Supérieure, 75005 Paris, France.
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12
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Otsu Y, Murphy TH. Optical postsynaptic measurement of vesicle release rates for hippocampal synapses undergoing asynchronous release during train stimulation. J Neurosci 2004; 24:9076-86. [PMID: 15483126 PMCID: PMC6730064 DOI: 10.1523/jneurosci.2060-04.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 08/31/2004] [Accepted: 09/02/2004] [Indexed: 11/21/2022] Open
Abstract
Developing hippocampal neurons in microisland culture were found to undergo rapid depression of excitatory synaptic activity caused by consumption of their readily releasable pool (RRP) of vesicles in response to 20 Hz trains of stimulation. Associated with depression was a switch to an asynchronous release mode that maintained transmission at a high steady-state rate equivalent to approximately 2.1 RRPs per second. We have applied postsynaptic Ca2+ imaging to directly monitor these asynchronous release events to estimate both the steady rate of transmitter release and the number of quanta within the RRP at individual hippocampal synapses. Based on the frequency of asynchronous release measured at individual synapses postsynaptically using Ca2+ imaging (5-17 sec after train stimulation) and with knowledge of the time course by which asynchronous release rates decay, we estimate that individual hippocampal synapses exhibit (in response to train stimulation) peak release rates of up to 21 quanta per second from an RRP that contains, on average, 10 quanta. Use-dependent block of evoked synaptic activity by MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d]cyclohepten-5,10-imine maleate] confirmed that synapses undergoing asynchronous release are not significantly different from the general population with regard to their composition of NMDA receptor and/or release probability. Given that high-frequency trains deplete the synapse of readily releasable quanta (and that these release rates can only be maintained for a few seconds), these high rates of asynchronous release likely reflect refilling of vesicles from a reserve pool and not necessarily the continuous action of a relatively slow clathrin- and endosome-dependent process.
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Affiliation(s)
- Yo Otsu
- Kinsmen Laboratory and Brain Research Center, University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
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13
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Otsu Y, Shahrezaei V, Li B, Raymond LA, Delaney KR, Murphy TH. Competition between phasic and asynchronous release for recovered synaptic vesicles at developing hippocampal autaptic synapses. J Neurosci 2004; 24:420-33. [PMID: 14724240 PMCID: PMC6729994 DOI: 10.1523/jneurosci.4452-03.2004] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Developing hippocampal neurons in microisland culture undergo rapid and extensive transmitter release-dependent depression of evoked (phasic) excitatory synaptic activity in response to 1 sec trains of 20 Hz stimulation. Although evoked phasic release was attenuated by repeated stimuli, asynchronous (miniature like) release continued at a high rate equivalent to approximately 2.8 readily releasable pools (RRPs) of quanta/sec. Asynchronous release reflected the recovery and immediate release of quanta because it was resistant to sucrose-induced depletion of the RRP. Asynchronous and phasic release appeared to compete for a common limited supply of release-ready quanta because agents that block asynchronous release, such as EGTA-AM, led to enhanced steady-state phasic release, whereas prolongation of the asynchronous release time course by LiCl delayed recovery of phasic release from depression. Modeling suggested that the resistance of asynchronous release to depression was associated with its ability to out-compete phasic release for recovered quanta attributable to its relatively low release rate (up to 0.04/msec per vesicle) stimulated by bulk intracellular Ca2+ concentration ([Ca2+]i) that could function over prolonged intervals between successive stimuli. Although phasic release was associated with a considerably higher peak rate of release (0.4/msec per vesicle), the [Ca2+]i microdomains that trigger it are brief (1 msec), and with asynchronous release present, relatively few quanta can accumulate within the RRP to be available for phasic release. We conclude that despite depression of phasic release during train stimulation, transmission can be maintained at a near-maximal rate by switching to an asynchronous mode that takes advantage of a bulk presynaptic [Ca2+]i.
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Affiliation(s)
- Yo Otsu
- Kinsmen Laboratory and Brain Research Centre, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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14
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Nagano T, Yanagawa Y, Obata K, Narisawa-Saito M, Namba H, Otsu Y, Takei N, Nawa H. Brain-derived neurotrophic factor upregulates and maintains AMPA receptor currents in neocortical GABAergic neurons. Mol Cell Neurosci 2004; 24:340-56. [PMID: 14572457 DOI: 10.1016/s1044-7431(03)00172-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors is implicated in synaptic plasticity. Although we have found that brain-derived neurotrophic factor (BDNF) triggers surface translocation of AMPA receptor proteins, the physiological significance of the BDNF effect remained to be determined. The present immunohistochemical studies revealed that cortical GABAergic neurons exhibited the most striking response to BDNF. Accordingly, we monitored AMPA-triggered currents through GABAergic neurons: Chronic BDNF treatment increased the AMPA-triggered currents but not NMDA-triggered currents in culture. In parallel, the amplitude, but not frequency, of spontaneous miniature excitatory postsynaptic currents (mEPSCs) was elevated in GABAergic neurons. In agreement, BDNF enhanced GABA release triggered by AMPA compared to the amount triggered by high potassium. Conversely, there was a significant decrease in the mEPSC amplitude of GABAergic neurons in heterozygous BDNF-knockout mice. These findings indicate that the neurotrophin enhances the input sensitivity of GABAergic neurons to facilitate their inhibitory function in the neocortex.
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Affiliation(s)
- T Nagano
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, 951-8585 Nigata, Japan
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15
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Li B, Otsu Y, Murphy TH, Raymond LA. Developmental decrease in NMDA receptor desensitization associated with shift to synapse and interaction with postsynaptic density-95. J Neurosci 2003; 23:11244-54. [PMID: 14657184 PMCID: PMC6741033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
NMDA receptors (NMDARs) play a crucial role in neuronal development, synaptic plasticity, and excitotoxicity; therefore, regulation of NMDAR function is important in both physiological and pathological conditions. Previous studies indicate that the NMDAR-mediated synaptic current decay rate increases during development because of a switch in receptor subunit composition, contributing to developmental changes in plasticity. To test whether NMDAR desensitization also changes during development, we recorded whole-cell NMDA-evoked currents in cultured rat hippocampal neurons. We found that glycine-independent desensitization of NMDARs decreases during development. This decrease was not dependent on a switch in subunit composition or differential receptor sensitivity to agonist-, Ca2+-, or Zn2+-induced increase in desensitization. Instead, several lines of evidence indicated that the developmental decrease in desensitization was tightly correlated with synaptic localization of the receptor, suggesting that association of NMDARs with proteins selectively expressed at synapses in mature neurons might account for developmental alterations in desensitization. Accordingly, we tested the role of interactions between PSD-95 (postsynaptic density-95) and NMDARs in regulating receptor desensitization. Overexpression of PSD-95 reduced NMDAR desensitization in immature neurons, whereas agents that interfere with synaptic targeting of PSD-95, or induce movement of NMDARs away from synapses and uncouple the receptor from PSD-95, increased NMDAR desensitization in mature neurons. We conclude that synaptic localization and association with PSD-95 increases stability of hippocampal neuronal NMDAR responses to sustained agonist exposure. Our results elucidate an additional mechanism for differentially regulating NMDAR function in neurons of different developmental stages or the response of subpopulations of NMDARs in a single neuron.
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Affiliation(s)
- Bo Li
- Kinsmen Laboratory, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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16
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Abstract
Miniature transmitter release results from the constitutive low-level release of individual vesicles of neurotransmitter. Since the 1950s, this form of synaptic transmission has largely been thought to reflect a leaky evoked-release mechanism, and it was not clear whether it had a function of its own. Recent data challenge this view and suggest that miniature release can affect both the local chemistry of synapses and the network properties of neurons.
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Affiliation(s)
- Yo Otsu
- Kinsmen Laboratory and Brain Research Centre, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3
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17
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Affiliation(s)
- Yo Otsu
- Kinsmen Laboratory and Brain Research Centre, Vancouver, BC, Canada V6T 1Z3
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18
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Takikawa Y, Mori H, Otsu Y, Matsuda Y, Nonomura T, Kakutani K, Tosa Y, Mayama S, Toyoda H. Rapid detection of phylloplane bacterium Enterobacter cloacae based on chitinase gene transformation and lytic infection by specific bacteriophages. J Appl Microbiol 2003; 93:1042-50. [PMID: 12452961 DOI: 10.1046/j.1365-2672.2002.01789.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To establish a rapid and efficient method for detecting Enterobacter cloacae based on chitinase gene transformation and lytic infection by virulent bacteriophages. METHODS AND RESULTS A phylloplane strain of E. cloacae was isolated from tomato leaves and transformed with a chitinase gene. Transformed bacteria were collected from single colonies and infected with newly isolated, virulent bacteriophages in the presence of the chitinase substrate 4-methylumbelliferon (4MU)-(GlcNac)3. To assay chitinase activity in the lysates, the product 4MU was measured spectrofluorophotometrically or visibly detected under u.v. irradiation. Chitinase gene-transformed bacteria obtained from single colonies could be specifically identified in 30 min by the emission of 4MU fluorescence following lysis caused by phage infection. CONCLUSIONS The chitinase gene was used as a reporter gene to construct a new system for easy and rapid monitoring of transgenic strains of E. cloacae released in the environment, in combination with specific recognition by virulent bacteriophages. SIGNIFICANCE AND IMPACT OF THE STUDY The assay is simple, rapid, inexpensive, easy to perform and applicable to other strains. The system can be used for the routine monitoring of bacteria, which is important because of the increased use of transgenic strains of E. cloacae as an antagonistic biological control agent for plant diseases.
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Affiliation(s)
- Y Takikawa
- Laboratory of Plant Pathology and Biotechnology, Kinki University, Higashi-Osaka, Japan
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19
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Abstract
A variety of processes limit NMDA (N-methyl-D-aspartate) receptor (NMDAR) activity in response to agonist exposure, including rundown--the decline of peak current with repeated, sustained agonist application. Here we report that calcium and tyrosine phosphorylation differentially regulate rundown of synaptic versus extrasynaptic NMDAR-mediated current in rat hippocampal pyramidal neurons.
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Affiliation(s)
- Bo Li
- Kinsmen Laboratory, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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20
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Osera S, Hidaka K, Tanabe K, Kamata M, Ninagawa K, Sakai R, Otsu Y. [Necessity of co-operation of the community medical system based on the results from the survey by questionnaires-participation of the home healthcare and/or hospice systems in southern Tama community hospitals]. Gan To Kagaku Ryoho 2001; 28 Suppl 1:94-7. [PMID: 11787304] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Home Care Division of Fujisawa Pharmaceutical Co. Ltd. has been providing the local public with the following services: 1) providing aseptic medicines prescribed in the clean room, 2) renting the infusion fluid pumps, and 3) supporting the community cooperation in healthcare services. Last year, we surveyed questionnaires to the public users (patients and caretakers) of these services, in order to understand the actual status of patients after changing from conventional hospitalization to the home infusion therapy (HIT). From the results of our present survey, it was found that the patients and their family members had positively accepted HIT, while 61% of the HIT users exhibited a strong anxiety in their skills and methods of HIT. Moreover, it was also shown that 61% had other means of nursing and treatment in addition to HIT, indicating a great financial burden on the families. Among them, 69% of the HIT users considered that visiting nurses and primary care physicians were the best co-operators, and changed their conventional healthcare system (hospitalization) to HIT. However, the home caretakers showed a high anxiety in their skill in the home healthcare system, specifically HIT, which was generally highly dependent on the medical care, Thus, a good relationship and co-operation with visiting nurses and primary care physicians was one of the major factors for the users to decide to choose HIT instead of their old medical hospitalization. Therefore, in order to make HIT more useful and widely prevail, it is concluded that establishment of the co-operative systems within our local community, where visiting nurses and primary care physicians can easily provide the patients and their family with professional suggestions, advice and actual care whenever the home caretakers need them.
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Affiliation(s)
- S Osera
- Home Care Division, Fujisawa Pharmaceutical Co. Ltd
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21
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Otsu Y, Maru E, Ohata H, Takashima I, Kajiwara R, Iijima T. Optical recording study of granule cell activities in the hippocampal dentate gyrus of kainate-treated rats. J Neurophysiol 2000; 83:2421-30. [PMID: 10758143 DOI: 10.1152/jn.2000.83.4.2421] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the epileptic hippocampus, newly sprouted mossy fibers are considered to form recurrent excitatory connections to granule cells in the dentate gyrus and thereby increase seizure susceptibility. To study the effects of mossy fiber sprouting on neural activity in individual lamellae of the dentate gyrus, we used high-speed optical recording to record signals from voltage-sensitive dye in hippocampal slices prepared from kainate-treated epileptic rats (KA rats). In 14 of 24 slices from KA rats, hilar stimulation evoked a large depolarization in almost the entire molecular layer in which granule cell apical dendrites are located. The signals were identified as postsynaptic responses because of their dependence on extracellular Ca(2+). The depolarization amplitude was largest in the inner molecular layer (the target area of sprouted mossy fibers) and declined with increasing distance from the granule cell layer. In the inner molecular layer, a good correlation was obtained between depolarization size and the density of mossy fiber terminals detected by Timm staining methods. Blockade of GABAergic inhibition by bicuculline enlarged the depolarization in granule cell dendrites. Our data indicate that mossy fiber sprouting results in a large and prolonged synaptic depolarization in an extensive dendritic area and that the enhanced GABAergic inhibition partly masks the synaptic depolarization. However, despite the large dendritic excitation induced by the sprouted mossy fibers, seizure-like activity of granule cells was never observed, even when GABAergic inhibition was blocked. Therefore, mossy fiber sprouting may not play a critical role in epileptogenesis.
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Affiliation(s)
- Y Otsu
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
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22
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Ibaraki K, Otsu Y, Nawa H. A novel two-site enzyme immunoassay reveals the regional distributions of and developmental changes in GluR1 and NMDAR1 protein contents in the rat brain. J Neurochem 1999; 73:408-17. [PMID: 10386994 DOI: 10.1046/j.1471-4159.1999.0730408.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glutamate receptors, including the alpha-amino-3-hydroxy-4-methylisoxazole-4-propionic acid (AMPA) and NMDA receptors, play an important role in neural development and synaptic plasticity in the brain. To date, it has been difficult to correlate accurately individual biochemical phenomena with quantitative and qualitative changes in receptors occurring in specific neurons or synapses. In the present study, we established a two-site enzyme immunoassay for two key subunits of the AMPA and NMDA receptors. Its sensitivities were extremely high, 30 pg for GluR1 and 15 pg for the NMDAR1 receptor containing the C2 exon [NMDAR1(C2)], which enabled us to measure their contents in a few milligrams of hippocampal tissue. Regional and developmental variations in receptor protein levels were much more marked than those reported for mRNA: The absolute GluR1 protein content was highest in the rat hippocampus, whereas the NMDAR1(C2) content was high in all the forebrain regions examined. GluR1 protein levels increased most markedly during the second and third weeks of postnatal life, whereas NMDAR1(C2) content increased during the first postnatal week. In the adult rat brain, the ratio of GluR1 protein to NMDAR1 protein was markedly lower in neocortical regions (approximately 2%) and the highest in cerebellum (22%). Therefore, this two-site enzyme immunoassay is a specific and unique method that enables us to measure absolute tissue contents of the glutamate receptors and will lead to further important discoveries on the biochemical alterations of these receptors.
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Affiliation(s)
- K Ibaraki
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Japan
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Abstract
We tried to identify the mechanisms directly related to syntactic processing in an fMRI experiment using strictly controlled sets of verbal stimuli. In two conditions, center-embedding and left-branching conditions, the same sets of words were used to construct stimulus sentences, while only the word order reflecting their syntactic structure was different. The subject's task was to understand the relationship among three characters mentioned in the sentences. A difference of activation in Broca's area (BA44 and 45) between the two conditions was found. This result suggests that these areas are involved in syntax-related processing. Furthermore, it was suggested that the posterior part of the frontal lobe (BA6/9) and the inferior parietal area (BA39/40) are involved in the understanding of the relationship among the three characters mentioned in each sentence.
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Affiliation(s)
- T Inui
- Graduate School of Informatics, Kyoto University, Japan
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24
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Ibaraki K, Otsu Y, Nawa H. A novel two-site enzyme immunoassay reveals regional distributions and developmental changes of GluR1 and NMDAR1 proteins in the rat brain. Neurosci Res 1998. [DOI: 10.1016/s0168-0102(98)81888-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kimura F, Otsu Y, Tsumoto T. Presynaptically silent synapses: spontaneously active terminals without stimulus-evoked release demonstrated in cortical autapses. J Neurophysiol 1997; 77:2805-15. [PMID: 9163394 DOI: 10.1152/jn.1997.77.5.2805] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
This study addresses the question of whether synapses that are capable of releasing transmitters spontaneously can also release them in an excitation-dependent manner. For this purpose, whole cell patch recordings were performed for a total of 48 excitatory solitary neurons in a microisland culture to observe excitatory autaptic currents elicited by spontaneous transmitter release as well as by somatic excitation. A somatic Na+-spike, induced in response to a short voltage step, evoked excitatory postsynaptic currents (EPSCs) of various amplitudes through the autapses; in some cases, no response was noticeable. To make sure that the recorded autaptic spontaneous EPSCs (sEPSCs) under a voltage clamp resulted from independent release of transmitters and were not associated with action potentials, sEPSCS in the presence and absence of tetrodotoxin (TTX) were compared in six cells. In the presence of TTX the evoked EPSCs were completely eliminated, whereas the sEPSCs were still observed and the amplitude distribution histograms were statistically not different from those recorded in the absence of TTX. A quantitative analysis of the sEPSCs (presumably miniature EPSCs) showed that the amplitude of stimulus-evoked EPSCs did not correlate with either the frequency or median amplitudes of the sEPSCs or the age of the culture. To identify whether the absence of stimulus-evoked response was caused either by conduction failure of excitation along the axons or by impairment of the release machinery that links the terminal depolarization to vesicle exocytosis, we examined whether high K+ and hypertonic solutions could facilitate the spontaneous release of transmitters. Although the hypertonic solution increased the spontaneous release in all cells tested (n = 18), the high K+ solution had a differential effect in increasing spontaneous release, i.e., the cells with larger evoked responses were more readily facilitated by the high K+ solution. Because the high K+ solution induced depolarization of presynaptic terminals, the present results indicated that the smaller evoked responses were due to the larger number of impaired or "silent" presynaptic terminals that were unable to link presynaptic depolarization to transmitter release. In summary, the present experiments provided evidence that at least some of the presynaptic terminals are silent in response to stimuli, while remaining spontaneously active at the same time. Because this phenomenon is due to the lack of sensitivity to depolarization at the terminals, these synaptic terminals seem incapable of linking terminal depolarization to transmitter release.
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Affiliation(s)
- F Kimura
- Department of Neurophysiology, Biomedical Research Center, Osaka University Medical School, Suita, Japan.
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Nawa H, Otsu Y. [Neurotrophic factors and synaptic plasticity in the central nervous system]. Tanpakushitsu Kakusan Koso 1996; 41:2513-21. [PMID: 8958758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- H Nawa
- Department of Molecular Neurobiology, Niigata University, Japan
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27
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Abstract
1. To see whether presynaptic activation paired with postsynaptic depolarization is necessary for the induction of long-term potentiation (LTP) in visual cortex or whether an activation of postsynaptic receptors in conjunction with depolarization is sufficient, we carried out perforated patch-clamp recordings with nystatin from cultured cortical neurons of rats. 2. Recorded neurons were monosynaptically activated either by electrical stimulation of an adjacent neuron or by direct activation of glutamate on "hot spots" of dendrites through iontophoresis or pressure ejection. In experiments in which cultured neurons were stained immunocytochemically with antibody against synaptophysin after electrophysiological recordings, hot spots were found to correspond to probable synaptic sites. 3. Excitatory postsynaptic currents (EPSCs) evoked by test stimulation applied to the adjacent neuron at 0.1 Hz were recorded at a holding potential of -60 or -70 mV for 5-10 min after an establishment of the whole cell recording configuration. Then, stimulation was paired with postsynaptic depolarization (0 mV for 200 ms) at 1 Hz for 30 or 60 s. LTP of EPSCs was induced in 7 of the 15 cells from which stable recordings were obtained for 18-30 min after pairing. 4. When postsynaptic depolarization was paired with direct glutamate application in the absence of presynaptic stimulation in 12 cells, only 1 showed LTP. Postsynaptic depolarization alone did not induce LTP in any of the six cells tested. Also, presynaptic stimulation alone did not induce LTP in any of the five cells tested. 5. These results suggest that the concurrent activation of presynaptic elements with postsynaptic depolarization is necessary for the induction of LTP in visual cortex.
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Affiliation(s)
- Y Otsu
- Department of Neurophysiology, Osaka University Medical School, Suita, Japan
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Abstract
Long-term depression (LTD) of synaptic transmission, often used as an essential component in synaptic models for learning, memory and forgetting, can be produced in layer II/III of the visual cortex by a prolonged, low-frequency stimulation (LFS) of layer IV. The activation of Ca2+/calmodulin-dependent protein phosphatase, calcineurin, has been postulated to play a role in the induction of LTD. The recent introduction of a specific inhibitor for calcineurin, FK506, prompted the investigation of the involvement of this phosphatase in the induction of LTD in visual cortex. Thus, we administered FK506 at 1 microM to visual cortical slices of young rats, and found that it did not significantly affect field responses of layer II/III evoked by test stimulation of layer IV at 0.1 Hz, but prevented LTD of the responses from being induced by LFS (1 Hz for 15 min) in all the 10 slices tested. Without FK506, significant LTD was induced by the same parameters of LFS in 8 of the 12 slices. These results suggest the critical involvement of calcineurin in producing LTD in visual cortex.
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Affiliation(s)
- N Torii
- Department of Neurophysiology, Osaka University Medical School, Suita, Japan
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Kato T, Otsu Y, Furune Y, Yamamoto T. Different effects of L-, N- and T-type calcium channel blockers on striatal dopamine release measured by microdialysis in freely moving rats. Neurochem Int 1992; 21:99-107. [PMID: 1303146 DOI: 10.1016/0197-0186(92)90072-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Using a microdialysis method, we have investigated effects of the voltage-dependent calcium channel blockers, verapamil, nicardipine, omega-conotoxin and flunarizine on the dopamine release and metabolism in the striatum of freely moving rat. Perfusion of verapamil (1-300 microM) and nicardipine (1-100 microM), an L-type calcium channel blocker, into the striatum through the dialysis membrane showed a dose-dependent decrease of dopamine release in the dialysate and slight increase of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels. Treatment of omega-conotoxin (0.1, 1 microM), an N-type channel blocker, decreased about 50% basal dopamine release and slightly decreased DOPAC and HVA levels. Treatment with flunarizine (10 microM), an T-type channel blocker, did not affect the dopamine release and metabolism. From these data, it appears that treatments of the L- and N-type voltage-dependent calcium channel blockers in rat striatum suppress basal dopamine release, but T-type blocker does not suppress it, suggesting that L-, N- and T-type calcium channels regulate in vivo dopamine release in a different mechanism.
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Affiliation(s)
- T Kato
- Laboratory of Molecular Recognition, Graduate School of Integrated Science, Yokohama City University, Japan
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30
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Otsu Y, Kimura H, Aoyama T. Methylisobutylxanthine, a potent inhibitor of cAMP phosphodiesterase, enhances the sensitivity of Chinese hamster ovary cells to mitomycin C. Chem Biol Interact 1987; 64:13-22. [PMID: 2446786 DOI: 10.1016/0009-2797(87)90057-3] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of 1-methyl-3-isobutylxanthine (MIX) on the sensitivity of CHO cells to mitomycin C (MC) was examined. Treatment of cells with MIX before MC-exposure greatly enhanced the cellular sensitivity to MC, with no effect on plating efficiency. Treatment with MIX after MC-exposure had only a slight effect. The sensitivity to MC was enhanced, biphasically, with increases in the period of pretreatment with MIX. The sensitivity of cells to MC fluctuated through the cell cycle, in that they were most sensitive to MC in G1 and resistant in the G2/M phase. Flow cytometric studies revealed a partial accumulation of cells in G1 (12% increase) at 16 h after MIX treatment. This means that the enhanced sensitivity with MIX pretreatment may partly depend on the accumulation of the cells in G1 and which are sensitive to MC. However, other cellular processes may also be involved, since the accumulation in G1 cannot explain all of the sensitization.
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Affiliation(s)
- Y Otsu
- Department of Experimental Radiology, Shiga University of Medical Science, Japan
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31
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Ishii K, Koga Y, Onitsuka T, Nakamura K, Yonezawa T, Mine K, Noda Y, Otsu Y, Yoshioka M, Hayashi A. [A case of successful surgical management of left ventricular pseudoaneurysm]. Kyobu Geka 1986; 39:735-9. [PMID: 3795671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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32
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Otsu Y, Choh T, Yamazaki I, Kosaka K, Iguchi M, Nakajima I. Experiments on the quick-relief medical communications via the Japan's domestic communication satellite CS-2 for the case of disasters and emergencies. Acta Astronaut 1986; 13:459-466. [PMID: 11542833 DOI: 10.1016/0094-5765(86)90099-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Experiments on the quick-relief medical communications via the CS-2 satellite were carried out by using two types of 30/20 GHz small transportable earth stations whose antenna diameters are 1 and 2 m. As the terminal equipments, FM-SCPC systems with a one-telephone-equivalent channel were prepared for the transmission of voice, color freezed picture (9.6 kbps), supersonic echo signal and heart sound from a electrocardiograph. Signals from various medical equipments were transmitted by an FM-SCPC system from Simizu harbour (1 m station) to Tokyo transportable station (2 m), assuming that a person was injured in the ship and the ship came alongside the pier. Transmitted materials are mainly various kinds of pictures of affected parts, X-ray films and electrocardiograph with breathing sounds. It was found possible to send various medical information mentioned above via CS-2 by the 30/20 GHz simple communication systems with one-telephone-equivalent channel. Doctors suggested it would be possible to judge very well about the patients' emergency conditions and to give quick consult with inevitable treatment procedures for them. However, a few problems were found in the Hi-Fi reproduction of original colors and in the transmission of heart sounds in the very low frequency band less than 300 Hz.
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Affiliation(s)
- Y Otsu
- Radio Research Laboratory (RRL), Ministry of Posts and Telecommunications (MPT), Tokyo, Japan
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Shinohara S, Otsu Y, Yamada T, Kimura H, Aoyama T. Modification of the sensitivity of CHO cells to mitomycin C by dibutyryl cyclic AMP. Biochem Biophys Res Commun 1983; 111:247-52. [PMID: 6299289 DOI: 10.1016/s0006-291x(83)80143-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The survival of CHO cells exposed to mitomycin C was decreased three times that of the cells treated with 1 mM dibutyryl cyclic AMP before mitomycin C treatment, as compared to the absence of treatment with this cyclic nucleotide. The sensitization effect began at 3-4 hours after the start of pre-treatment, reached a maximum at around 10 hours and continued to be effective. Post-treatment with the cyclic nucleotide for more than 12 hours increased the survival of CHO cells exposed to mitomycin C.
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Hayashi K, Otsu Y, Tani T. [Intrauterine death of rat embryo due to delayed implantation caused by reserpine and the study of chromosome of the surviving newborn animals]. Horumon To Rinsho 1973; 21:959-64. [PMID: 4797175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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35
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Hayashi K, Takekida H, Tani T, Otsu Y, Matsuoka K. [Endocrine control of pregnancy]. Horumon To Rinsho 1972; 20:693-700. [PMID: 4568672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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