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Yamamoto S, Takahashi Y, Kato F. Input-dependent synaptic suppression by pregabalin in the central amygdala in male mice with inflammatory pain. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2021; 10:100078. [PMID: 34877437 PMCID: PMC8628014 DOI: 10.1016/j.ynpai.2021.100078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/14/2021] [Accepted: 11/14/2021] [Indexed: 04/12/2023]
Abstract
Pregabalin (PGB) is a synthetic amino acid compound most widely prescribed for chronic peripheral and central neuropathic pain. PGB is a ligand for the α2δ1 subunit of voltage-dependent calcium channels, and its binding reduces neurotransmitter release and thus inhibits synaptic transmission. The central nucleus of the amygdala (CeA) is a kernel site for the enhanced nociception-emotion link in chronic pain. The nociceptive information is conveyed to the CeA via the following two pathways: 1) the pathway arising from the basolateral amygdala (BLA), which carries nociceptive information mediated by the thalamocortical system, and 2) that arising from the external part of the pontine lateral parabrachial nucleus (LPB), that forms the final route of the spino-parabrachio-amygdaloid pathway that conveys nociceptive information directly from the superficial layer of the spinal dorsal horn. We compared the effects of PGB on the excitatory postsynaptic currents of neurons in the right CeA in response to electrical stimulation of BLA and LPB pathways using the whole-cell patch-clamp technique. Inflammatory pain was induced by intraplantar injection of formalin solution at the left hind paw. At eight hours post-formalin, PGB reduced EPSCs amplitude of the BLA-to-CeA synaptic transmission, accompanied by a significant increase in the PPR, suggesting a decreased release probability from the presynaptic terminals. In addition, these effects of PGB were only seen in inflammatory conditions. PGB did not affect the synaptic transmission at the LPB-to-CeA pathway, even in formalin-treated mice. These results suggest PGB improves not simply the aberrantly enhanced nociception but also various pain-associated cognitive and affective consequences in patients with chronic nociplastic pain.
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Affiliation(s)
- Sumii Yamamoto
- Department of Anesthesiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Department of Neuroscience, The Jikei University School of Medicine, Minato, Tokyo 105-8461, Japan
| | - Yukari Takahashi
- Department of Neuroscience, The Jikei University School of Medicine, Minato, Tokyo 105-8461, Japan
- Center for Neuroscience of Pain, The Jikei University School of Medicine, Minato, Tokyo 105-8461, Japan
| | - Fusao Kato
- Department of Neuroscience, The Jikei University School of Medicine, Minato, Tokyo 105-8461, Japan
- Center for Neuroscience of Pain, The Jikei University School of Medicine, Minato, Tokyo 105-8461, Japan
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Pascoaloti-Lima JC, Machado BH, Accorsi-Mendonça D. Sustained Hypoxia Reduces GABAergic Modulation on NTS Neurons Sending Projections to Ventral Medulla of Rats. Neuroscience 2021; 457:1-11. [PMID: 33421568 DOI: 10.1016/j.neuroscience.2020.12.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 11/26/2022]
Abstract
Peripheral chemoreflex is activated during short-term sustained hypoxia (SH), and the first synapse of these afferents is located in Nucleus Tractus Solitarius(NTS). NTS neurons projecting to the ventral lateral medulla (NTS-VLM) are part of the respiratory pathways of the chemoreflex. SH increases the magnitude of basal respiratory parameters in rats from Wistar-Hannover strain. In this study, we hypothesized that the observed changes in the respiratory pattern in response to SH were due to changes in the GABAergic modulation of the synaptic transmission of NTS-VLM neurons. We used an electrophysiological approach to record the synaptic activity of NTS neurons labeled with a retrograde tracer previously microinjected into VLM of Wistar-Hannover rats submitted to 24 h SH. The data are showing that: (a) the amplitude of evoked inhibitory currents in NTS-VLM neurons of SH rats was reduced and not accompanied by any change in rise-time and decay-time; (b) the 1/CV2 and the number of failures in response to evoked currents were also affected by SH; (c) the frequency of spontaneous inhibitory currents was reduced by SH without changes in amplitude and half-width. These effects of SH were observed in NTS-VLM neurons located in caudal and intermediate NTS, but not in NTS-VLM neurons located in the rostral NTS. We conclude that SH causes a reduction in inhibitory modulation onto NTS-VLM neurons by pre-synaptic mechanisms, which may contribute to the observed changes in the respiratory pattern of Wistar-Hannover rats submitted to SH.
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Affiliation(s)
- Júlio C Pascoaloti-Lima
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Daniela Accorsi-Mendonça
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Zhang HT, Park TJ, Zaluzhnyy IA, Wang Q, Wadekar SN, Manna S, Andrawis R, Sprau PO, Sun Y, Zhang Z, Huang C, Zhou H, Zhang Z, Narayanan B, Srinivasan G, Hua N, Nazaretski E, Huang X, Yan H, Ge M, Chu YS, Cherukara MJ, Holt MV, Krishnamurthy M, Shpyrko OG, Sankaranarayanan SKRS, Frano A, Roy K, Ramanathan S. Perovskite neural trees. Nat Commun 2020; 11:2245. [PMID: 32382036 PMCID: PMC7206050 DOI: 10.1038/s41467-020-16105-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 04/07/2020] [Indexed: 11/20/2022] Open
Abstract
Trees are used by animals, humans and machines to classify information and make decisions. Natural tree structures displayed by synapses of the brain involves potentiation and depression capable of branching and is essential for survival and learning. Demonstration of such features in synthetic matter is challenging due to the need to host a complex energy landscape capable of learning, memory and electrical interrogation. We report experimental realization of tree-like conductance states at room temperature in strongly correlated perovskite nickelates by modulating proton distribution under high speed electric pulses. This demonstration represents physical realization of ultrametric trees, a concept from number theory applied to the study of spin glasses in physics that inspired early neural network theory dating almost forty years ago. We apply the tree-like memory features in spiking neural networks to demonstrate high fidelity object recognition, and in future can open new directions for neuromorphic computing and artificial intelligence.
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Affiliation(s)
- Hai-Tian Zhang
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
- Lillian Gilbreth Fellowship Program, College of Engineering, Purdue University, West Lafayette, IN, 47907, USA.
| | - Tae Joon Park
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Ivan A Zaluzhnyy
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Qi Wang
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Shakti Nagnath Wadekar
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Sukriti Manna
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, IL, 60607, USA
| | - Robert Andrawis
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Peter O Sprau
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yifei Sun
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhen Zhang
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Chengzi Huang
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Hua Zhou
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Zhan Zhang
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Badri Narayanan
- Department of Mechanical Engineering, University of Louisville, Louisville, KY, 40292, USA
| | | | - Nelson Hua
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Evgeny Nazaretski
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Xiaojing Huang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Hanfei Yan
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Mingyuan Ge
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Yong S Chu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Mathew J Cherukara
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Martin V Holt
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
| | | | - Oleg G Shpyrko
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Subramanian K R S Sankaranarayanan
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, IL, 60607, USA
| | - Alex Frano
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Kaushik Roy
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA.
| | - Shriram Ramanathan
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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Martinez D, Rogers RC, Hermann GE, Hasser EM, Kline DD. Astrocytic glutamate transporters reduce the neuronal and physiological influence of metabotropic glutamate receptors in nucleus tractus solitarii. Am J Physiol Regul Integr Comp Physiol 2020; 318:R545-R564. [PMID: 31967862 PMCID: PMC7099463 DOI: 10.1152/ajpregu.00319.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Astrocytic excitatory amino acid transporters (EAATs) are critical to restraining synaptic and neuronal activity in the nucleus tractus solitarii (nTS). Relief of nTS EAAT restraint generates two opposing effects, an increase in neuronal excitability that reduces blood pressure and breathing and an attenuation in afferent [tractus solitarius (TS)]-driven excitatory postsynaptic current (EPSC) amplitude. Although the former is due, in part, to activation of ionotropic glutamate receptors, there remains a substantial contribution from another unidentified glutamate receptor. In addition, the mechanism(s) by which EAAT inhibition reduced TS-EPSC amplitude is unknown. Metabotropic glutamate receptors (mGluRs) differentially modulate nTS excitability. Activation of group I mGluRs on nTS neuron somas leads to depolarization, whereas group II/III mGluRs on sensory afferents decrease TS-EPSC amplitude. Thus we hypothesize that EAATs control postsynaptic excitability and TS-EPSC amplitude via restraint of mGluR activation. To test this hypothesis, we used in vivo recording, brain slice electrophysiology, and imaging of glutamate release and TS-afferent Ca2+. Results show that EAAT blockade in the nTS with (3S)-3-[[3-[[4-(trifluoromethyl)benzoyl]amino]phenyl]methoxy]-l-aspartic acid (TFB-TBOA) induced group I mGluR-mediated depressor, bradycardic, and apneic responses that were accompanied by neuronal depolarization, elevated discharge, and increased spontaneous synaptic activity. Conversely, upon TS stimulation TFB-TBOA elevated extracellular glutamate to decrease presynaptic Ca2+ and TS-EPSC amplitude via activation of group II/III mGluRs. Together, these data suggest an important role of EAATs in restraining mGluR activation and overall cardiorespiratory function.
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Affiliation(s)
- Diana Martinez
- 1Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | | | | | - Eileen M. Hasser
- 1Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri,2Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - David D. Kline
- 1Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Usui M, Kaneko K, Oi Y, Kobayashi M. Orexin facilitates GABAergic IPSCs via postsynaptic OX 1 receptors coupling to the intracellular PKC signalling cascade in the rat cerebral cortex. Neuropharmacology 2019; 149:97-112. [PMID: 30763655 DOI: 10.1016/j.neuropharm.2019.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/06/2019] [Accepted: 02/10/2019] [Indexed: 10/27/2022]
Abstract
Orexin has multiple physiological functions including wakefulness, appetite, nicotine intake, and nociception. The cerebral cortex receives abundant orexinergic projections and expresses both orexinergic receptor 1 (OX1R) and 2 (OX2R). However, little is known about orexinergic regulation of GABA-mediated inhibitory synaptic transmission. In the cerebral cortex, there are multiple GABAergic neural subtypes, each of which has its own morphological and physiological characteristics. Therefore, identification of presynaptic GABAergic neural subtypes is critical to understand orexinergic effects on GABAergic connections. We focused on inhibitory synapses at pyramidal neurons (PNs) from fast-spiking GABAergic neurons (FSNs) in the insular cortex by a paired whole-cell patch-clamp technique, and elucidated the mechanisms of orexin-induced IPSC regulation. We found that both orexin A and orexin B enhanced unitary IPSC (uIPSC) amplitude in FSN→PN connections without changing the paired-pulse ratio or failure rate. These effects were blocked by SB-334867, an OX1 receptor (OX1R) antagonist, but not by TCS-OX2-29, an OX2R antagonist. [Ala11, D-Leu15]-orexin B, a selective OX2R agonist, had little effect on uIPSCs. Variance-mean analysis demonstrated an increase in quantal content without a change in release probability or the number of readily releasable pools. Laser photolysis of caged GABA revealed that orexin A enhanced GABA-mediated currents in PNs. Downstream blockade of Gq/11 protein-coupled OX1Rs by IP3 receptor or protein kinase C (PKC) blockers and BAPTA injection into postsynaptic PNs diminished the orexin A-induced uIPSC enhancement. These results suggest that the orexinergic uIPSC enhancement is mediated via postsynaptic OX1Rs, which potentiate GABAA receptors through PKC activation.
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Affiliation(s)
- Midori Usui
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Department of Anaesthesiology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Keisuke Kaneko
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Department of Anaesthesiology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Yoshiyuki Oi
- Department of Anaesthesiology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Masayuki Kobayashi
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Oral and Craniomaxillofacial Research, Dental Research Centre, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Molecular Dynamics Imaging Unit, RIKEN Centre for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan.
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Opposite Roles in Short-Term Plasticity for N-Type and P/Q-Type Voltage-Dependent Calcium Channels in GABAergic Neuronal Connections in the Rat Cerebral Cortex. J Neurosci 2018; 38:9814-9828. [PMID: 30249804 DOI: 10.1523/jneurosci.0337-18.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/23/2018] [Accepted: 07/28/2018] [Indexed: 12/23/2022] Open
Abstract
Neurotransmitter release is triggered by Ca2+ influx through voltage-dependent Ca2+ channels (VDCCs). Distinct expression patterns of VDCC subtypes localized on the synaptic terminal affect intracellular Ca2+ dynamics induced by action potential-triggered Ca2+ influx. However, it has been unknown whether the expression pattern of VDCC subtypes depends on each axon terminal or neuronal subtype. Furthermore, little information is available on how these VDCC subtypes regulate the release probability of neurotransmitters. To address these questions, we performed multiple whole-cell patch-clamp recordings from GABAergic neurons in the insular cortex of either the male or the female rat. The paired-pulse ratio (PPR; 50 ms interstimulus interval) varied widely among inhibitory connections between GABAergic neurons. The PPR of unitary IPSCs was enhanced by ω-conotoxin GVIA (CgTx; 3 μm), an N-type VDCC blocker, whereas blockade of P/Q-type VDCCs by ω-agatoxin IVA (AgTx, 200 nm) decreased the PPR. In the presence of CgTx, application of 4 mm [Ca2+]o or of roscovitine, a P/Q-type activator, increased the PPR. These results suggest that the recruitment of P/Q-type VDCCs increases the PPR, whereas N-type VDCCs suppress the PPR. Furthermore, we found that charybdotoxin or apamin, blockers of Ca2+-dependent K+ channels, with AgTx increased the PPR, suggesting that Ca2+-dependent K+ channels are coupled to N-type VDCCs and suppress the PPR in GABAergic neuronal terminals. Variance-mean analysis with changing [Ca2+]o showed a negative correlation between the PPR and release probability in GABAergic synapses. These results suggest that GABAergic neurons differentially express N-type and/or P/Q-type VDCCs and that these VDCCs regulate the GABA release probability in distinct manners.SIGNIFICANCE STATEMENT GABAergic neuronal axons target multiple neurons and release GABA triggered by Ca2+ influx via voltage-dependent Ca2+ channels (VDCCs), including N-type and P/Q-type channels. Little is known about VDCC expression patterns in GABAergic synaptic terminals and their role in short-term plasticity. We focused on inhibitory synaptic connections between GABAergic neurons in the cerebral cortex using multiple whole-cell patch-clamp recordings and found different expression patterns of VDCCs in the synaptic terminals branched from a single presynaptic neuron. Furthermore, we observed facilitative and depressive short-term plasticity of IPSCs mediated by P/Q-type and N-type VDCCs, respectively. These results suggest that VDCC expression patterns regulate distinctive types of synaptic transmission in each GABAergic axon terminal even though they are branched from a common presynaptic neuron.
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Matott M, Ciarlone G, Putnam R, Dean J. Normobaric hyperoxia (95% O2) stimulates CO2-sensitive and CO2-insensitive neurons in the caudal solitary complex of rat medullary tissue slices maintained in 40% O2. Neuroscience 2014; 270:98-122. [DOI: 10.1016/j.neuroscience.2014.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/09/2014] [Accepted: 03/10/2014] [Indexed: 12/13/2022]
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On-site energy supply at synapses through monocarboxylate transporters maintains excitatory synaptic transmission. J Neurosci 2014; 34:2605-17. [PMID: 24523550 DOI: 10.1523/jneurosci.4687-12.2014] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
ATP production through oxidative phosphorylation in the mitochondria is the most efficient way to provide energy to various energy-consuming activities of the neurons. These processes require a large amount of ATP molecules to be maintained. Of these, synaptic transmission is most energy consuming. Here we report that lactate transported through monocarboxylate transporters (MCTs) at excitatory synapses constitutively supports synaptic transmission, even under conditions in which a sufficient supply of glucose and intracellular ATP are present. We analyzed the effects of MCT inhibition on neuronal activities using whole-cell recordings in brain slices of rats in the nucleus of the solitary tract. MCT inhibitors (α-cyano-4-hydroxycinnamic acid (4-CIN), phloretin, and d-lactate) significantly decreased the amplitude of EPSCs without reducing release probability. Although 4-CIN significantly reduced currents mediated by heterologously expressed AMPA-Rs in oocytes (a novel finding in this study), the IC50 of the inhibitory effect on EPSC in brain slices was ∼3.8 times smaller than that on AMPA-R currents in oocytes. Removal of intracellular ATP significantly potentiated the inhibition of EPSC with 4-CIN in a manner that was counteracted by intracellular lactate addition. In addition, extracellular lactate rescued aglycemic suppression of EPSC, in a manner that was prevented by 4-CIN. Inhibition of MCTs also reduced NMDA-R-mediated EPSCs and, to a lesser extent, the IPSC. The reduction in EPSC amplitude by γ-d-glutamylglycine was enhanced by 4-CIN, suggesting also a decreased quantal content. We conclude that "on-site" astrocyte-neuron lactate transport to presynaptic and postsynaptic elements is necessary for the integrity of excitatory synaptic transmission.
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Morita S, Hourai A, Miyata S. Changes in pericytic expression of NG2 and PDGFRB and vascular permeability in the sensory circumventricular organs of adult mouse by osmotic stimulation. Cell Biochem Funct 2013; 32:51-61. [PMID: 23629811 DOI: 10.1002/cbf.2971] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 01/27/2023]
Abstract
The blood-brain barrier (BBB) is a barrier that prevents free access of blood-derived substances to the brain through the tight junctions and maintains a specialized brain environment. Circumventricular organs (CVOs) lack the typical BBB. The fenestrated vasculature of the sensory CVOs, including the organum vasculosum of the lamina terminalis (OVLT), subfornical organ (SFO) and area postrema (AP), allows parenchyma cells to sense a variety of blood-derived information, including osmotic ones. In the present study, we utilized immunohistochemistry to examine changes in the expression of NG2 and platelet-derived growth factor receptor beta (PDGFRB) in the OVLT, SFO and AP of adult mice during chronic osmotic stimulation. The expression of NG2 and PDGFRB was remarkably prominent in pericytes, although these angiogenesis-associated proteins are highly expressed at pericytes of developing immature vasculature. The chronic salt loading prominently increased the expression of NG2 in the OVLT and SFO and that of PDGFRB in the OVLT, SFO and AP. The vascular permeability of low-molecular-mass tracer fluorescein isothiocyanate was increased significantly by chronic salt loading in the OVLT and SFO but not AP. In conclusion, the present study demonstrates changes in pericyte expression of NG2 and PDGFRB and vascular permeability in the sensory CVOs by chronic osmotic stimulation, indicating active participation of the vascular system in osmotic homeostasis.
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Affiliation(s)
- Shoko Morita
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Japan; Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan
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Chronic intermittent hypoxia depresses afferent neurotransmission in NTS neurons by a reduction in the number of active synapses. J Neurosci 2013; 32:16736-46. [PMID: 23175827 DOI: 10.1523/jneurosci.2654-12.2012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Long-term synaptic plasticity has been recently described in brainstem areas associated to visceral afferent sensory integration. Chronic intermittent hypoxia (CIH), an animal model for studying obstructive sleep apnea in humans, depresses the afferent neurotransmission in nucleus tractus solitarii (NTS) neurons, which affect respiratory and autonomic regulation. Here we identified the synaptic mechanisms of CIH-induced depression of the afferent neurotransmission in NTS neurons in juvenile rats. We verified that CIH reduced the amplitude of both NMDA and non-NMDA glutamatergic excitatory currents (eEPSCs) evoked by tractus solitarii stimulation (TS-eEPSC) of second-order neurons in the NTS. No changes were observed in release probability, evidenced by absence of any CIH-elicited effects on short-term depression and failures in EPSCs evoked in low calcium. CIH also produced no changes in TS-eEPSC quantal size, since the amplitudes of both low calcium-evoked EPSCs and asynchronous TS-eEPSCs (evoked in the presence of Sr(2+)) were unchanged. Using single TS afferent fiber stimulation in slices from control and CIH rats we clearly show that CIH reduced the quantal content of the TS-eEPSCs without affecting the quantal size or release probability, suggesting a reduction in the number of active synapses as the mechanism of CIH induced TS-eEPSC depression. In accordance with this concept, the input-output relationship of stimulus intensity and TS-eEPSC amplitude shows an early saturation in CIH animals. These findings open new perspectives for a better understanding of the mechanisms underlying the synaptic plasticity in the brainstem sensory neurons under challenges such as those produced by CIH in experimental and pathological conditions.
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Nakao A, Takahashi Y, Nagase M, Ikeda R, Kato F. Role of capsaicin-sensitive C-fiber afferents in neuropathic pain-induced synaptic potentiation in the nociceptive amygdala. Mol Pain 2012; 8:51. [PMID: 22776418 PMCID: PMC3464693 DOI: 10.1186/1744-8069-8-51] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 07/09/2012] [Indexed: 12/04/2022] Open
Abstract
Background Neurons in the capsular part of the central nucleus of the amygdala (CeC), a region also called "nociceptive amygdala," receive nociceptive information from the dorsal horn via afferent pathways relayed from the lateral parabrachial nucleus (LPB). As the central amygdala is known to be involved in the acquisition and expression of emotion, this pathway is thought to play central roles in the generation of affective responses to nociceptive inputs. Excitatory synaptic transmission between afferents arising from the LPB and these CeC neurons is potentiated in arthritic, visceral, neuropathic, inflammatory and muscle pain models. In neuropathic pain models following spinal nerve ligation (SNL), in which we previously showed a robust LPB-CeC potentiation, the principal behavioral symptom is tactile allodynia triggered by non-C-fiber low-threshold mechanoreceptor afferents. Conversely, recent anatomical studies have revealed that most of the spinal neurons projecting to the LPB receive C-fiber afferent inputs. Here, we examined the hypothesis that these C-fiber-mediated inputs are necessary for the full establishment of robust synaptic potentiation of LPB-CeC transmission in the rats with neuropathic pain. Results Postnatal capsaicin treatment, which has been shown to denervate the C-fibers expressing transient receptor potential vanilloid type-1 (TRPV1) channels, completely abolished eye-wiping responses to capsaicin eye instillation in rats, but this treatment did not affect mechanical allodynia in the nerve-ligated animals. However, the postnatal capsaicin treatment prevented LPB-CeC synaptic potentiation after SNL, unlike in the vehicle-treated rats, primarily due to the decreased incidence of potentiated transmission by elimination of TRPV1-expressing C-fiber afferents. Conclusions C-fiber-mediated afferents in the nerve-ligated animals may be a required facilitator of the establishment of nerve injury-evoked synaptic potentiation in the CeC. These inputs might play essential roles in the chronic pain-induced plastic changes in the central network linking nociception and negative emotion.
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Affiliation(s)
- Ayano Nakao
- Laboratory of Neurophysiology, Department of Neuroscience, Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
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Accorsi-Mendonça D, Castania J, Bonagamba L, Machado B, Leão R. Synaptic profile of nucleus tractus solitarius neurons involved with the peripheral chemoreflex pathways. Neuroscience 2011; 197:107-20. [DOI: 10.1016/j.neuroscience.2011.08.054] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 08/22/2011] [Accepted: 08/24/2011] [Indexed: 10/17/2022]
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