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Tran CM, Ra JS, Rhyu DY, Kim KT. Transcriptome analysis reveals differences in developmental neurotoxicity mechanism of methyl-, ethyl-, and propyl- parabens in zebrafish embryos. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 268:115704. [PMID: 37979356 DOI: 10.1016/j.ecoenv.2023.115704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/26/2023] [Accepted: 11/13/2023] [Indexed: 11/20/2023]
Abstract
Studies on the comparison of developmental (neuro) toxicity of parabens are currently limited, and unharmonized concentrations between phenotypic observations and transcriptome analysis hamper the understanding of their differential molecular mechanisms. Thus, developmental toxicity testing was conducted herein using the commonly used methyl- (MtP), ethyl- (EtP), and propyl-parabens (PrP) in zebrafish embryos. With a benchmark dose of 5%, embryonic-mortality-based point-of-departure (M-POD) values of the three parabens were determined, and changes in locomotor behavior were evaluated at concentrations of 0, M-POD/50, M-POD/10, and M-POD, where transcriptome analysis was conducted to explore the underlying neurotoxicity mechanism. Higher long-chained parabens were more toxic than short-chained parabens, as determined by the M-POD values of 154.1, 72.6, and 24.2 µM for MtP, EtP, and PrP, respectively. Meanwhile, exposure to EtP resulted in hyperactivity, whereas no behavioral effect was observed with MtP and PrP. Transcriptome analysis revealed that abnormal behaviors in the EtP-exposed group were associated with distinctly enriched pathways in signaling, transport, calcium ion binding, and metal binding. In contrast, exposure to MtP and PrP mainly disrupted membranes and transmembranes, which are closely linked to abnormal embryonic development rather than neurobehavioral changes. According to the changes in the expressions of signature mRNAs, tentative transcriptome-based POD values for each paraben were determined as MtP (2.68 µM), EtP (3.85 µM), and PrP (1.4 µM). This suggests that different molecular perturbations initiated at similar concentrations determined the extent and toxicity outcome differently. Our findings provide insight into better understanding the differential developmental neurotoxicity mechanisms of parabens.
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Affiliation(s)
- Cong Minh Tran
- Department of Energy and Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
| | - Jin-Sung Ra
- Eco-testing and Risk Assessment Center, Korea Institute of Industrial Technology (KITECH), Ansan 15588, Republic of Korea
| | - Dong Young Rhyu
- Department of Biomedicine, Health & Life Convergence Sciences, BK21 FOUR, Mokpo National University, Jeonnam 58554, Republic of Korea
| | - Ki-Tae Kim
- Department of Energy and Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea; Department of Environmental Engineering, Seoul National University of Sciences and Technology, Seoul 01811, Republic of Korea.
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Pan Y, Zhang K, Wei H, Xiong T, Liu Y, Mao L, Yu P. Double-Barreled Micropipette Enables Neuron-Compatible In Vivo Analysis. Anal Chem 2022; 94:15671-15677. [DOI: 10.1021/acs.analchem.2c02739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yifei Pan
- Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing100190, China
- School of Chemical Science, University of Chinese Academy of Sciences (CAS), Beijing100190, China
| | - Kailin Zhang
- Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing100190, China
- School of Chemical Science, University of Chinese Academy of Sciences (CAS), Beijing100190, China
| | - Huan Wei
- Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing100190, China
- College of Chemistry, Beijing Normal University, Beijing100875, China
| | - Tianyi Xiong
- Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing100190, China
- School of Chemical Science, University of Chinese Academy of Sciences (CAS), Beijing100190, China
| | - Ying Liu
- Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing100190, China
- School of Chemical Science, University of Chinese Academy of Sciences (CAS), Beijing100190, China
| | - Lanqun Mao
- College of Chemistry, Beijing Normal University, Beijing100875, China
| | - Ping Yu
- Key Laboratory of Analytical Chemistry for Living Biosystems Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing100190, China
- School of Chemical Science, University of Chinese Academy of Sciences (CAS), Beijing100190, China
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Toyoda H, Won J, Kim W, Kim H, Davy O, Saito M, Kim D, Tanaka T, Kang Y, Oh SB. The Nature of Noradrenergic Volume Transmission From Locus Coeruleus to Brainstem Mesencephalic Trigeminal Sensory Neurons. Front Cell Neurosci 2022; 16:841239. [PMID: 35558874 PMCID: PMC9087804 DOI: 10.3389/fncel.2022.841239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/24/2022] [Indexed: 11/13/2022] Open
Abstract
Noradrenergic neurons in the locus coeruleus (LC) release noradrenaline (NA) that acts via volume transmission to activate extrasynaptic G-protein coupled receptors (GPCRs) in target cells throughout the brain. As the closest projection, the dorsal LC laterally adjoins the mesencephalic trigeminal nucleus (MTN), in which proprioceptive primary sensory neurons innervating muscle spindles of jaw-closing muscles are exceptionally located. MTN neurons express α2-adrenergic receptors (α2-ARs) and display hyperpolarization-activated cyclic nucleotide-gated (HCN) currents (Ihs), which is downregulated by α2-AR activation. To quantify the activity-dependent outcome of volume transmission of NA from LC to MTN, we investigated how direct LC activation inhibits Ih in MTN neurons by performing dual whole-cell recordings from LC and MTN neurons. Repetition of 20 Hz spike-train evoked with 1-s current-pulse in LC neurons every 30 s resulted in a gradual decrease in Ih evoked every 30 s, revealing a Hill-type relationship between the number of spike-trains in LC neurons and the degree of Ih inhibition in MTN neurons. On the other hand, when microstimulation was applied in LC every 30 s, an LC neuron repeatedly displayed a transient higher-frequency firing followed by a tonic firing at 5–10 Hz for 30 s. This subsequently caused a similar Hill-type inhibition of Ih in the simultaneously recorded MTN neuron, but with a smaller Hill coefficient, suggesting a lower signal transduction efficacy. In contrast, 20 Hz activity induced by a 1-s pulse applied every 5–10 s caused only a transient facilitation of Ih inhibition followed by a forced termination of Ih inhibition. Thus, the three modes of LC activities modulated the volume transmission to activate α2-adrenergic GPCR to differentially inhibit Ih in MTN neurons.
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Affiliation(s)
- Hiroki Toyoda
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Suita, Japan
| | - Jonghwa Won
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Wheedong Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Hayun Kim
- Interdisciplinary Program for Brain Science, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Oscar Davy
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Mitsuru Saito
- Department of Oral Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Doyun Kim
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Takuma Tanaka
- Graduate School of Data Science, Shiga University, Hikone, Japan
| | - Youngnam Kang
- Department of Neuroscience and Oral Physiology, Graduate School of Dentistry, Osaka University, Suita, Japan
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, South Korea
- Department of Behavioral Sciences, Graduate School of Human Sciences, Osaka University, Suita, Japan
| | - Seog Bae Oh
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Department of Neurobiology and Physiology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, South Korea
- Interdisciplinary Program for Brain Science, College of Natural Sciences, Seoul National University, Seoul, South Korea
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Miguel-Tomé S, Llinás RR. Broadening the definition of a nervous system to better understand the evolution of plants and animals. PLANT SIGNALING & BEHAVIOR 2021; 16:1927562. [PMID: 34120565 PMCID: PMC8331040 DOI: 10.1080/15592324.2021.1927562] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 05/10/2023]
Abstract
Most textbook definitions recognize only animals as having nervous systems. However, for the past couple decades, botanists have been meticulously studying long-distance signaling systems in plants, and some researchers have stated that plants have a simple nervous system. Thus, an academic conflict has emerged between those who defend and those who deny the existence of a nervous system in plants. This article analyses that debate, and we propose an alternative to answering yes or no: broadening the definition of a nervous system to include plants. We claim that a definition broader than the current one, which is based only on a phylogenetic viewpoint, would be helpful in obtaining a deeper understanding of how evolution has driven the features of signal generation, transmission and processing in multicellular beings. Also, we propose two possible definitions and exemplify how broader a definition allows for new viewpoints on the evolution of plants, animals and the nervous system.
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Affiliation(s)
- Sergio Miguel-Tomé
- Grupo De Investigación En Minería De Datos (Mida), Universidad De Salamanca, Salamanca, Spain
| | - Rodolfo R. Llinás
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA
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Moroz LL, Romanova DY, Kohn AB. Neural versus alternative integrative systems: molecular insights into origins of neurotransmitters. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190762. [PMID: 33550949 PMCID: PMC7935107 DOI: 10.1098/rstb.2019.0762] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Transmitter signalling is the universal chemical language of any nervous system, but little is known about its early evolution. Here, we summarize data about the distribution and functions of neurotransmitter systems in basal metazoans as well as outline hypotheses of their origins. We explore the scenario that neurons arose from genetically different populations of secretory cells capable of volume chemical transmission and integration of behaviours without canonical synapses. The closest representation of this primordial organization is currently found in Placozoa, disk-like animals with the simplest known cell composition but complex behaviours. We propose that injury-related signalling was the evolutionary predecessor for integrative functions of early transmitters such as nitric oxide, ATP, protons, glutamate and small peptides. By contrast, acetylcholine, dopamine, noradrenaline, octopamine, serotonin and histamine were recruited as canonical neurotransmitters relatively later in animal evolution, only in bilaterians. Ligand-gated ion channels often preceded the establishment of novel neurotransmitter systems. Moreover, lineage-specific diversification of neurotransmitter receptors occurred in parallel within Cnidaria and several bilaterian lineages, including acoels. In summary, ancestral diversification of secretory signal molecules provides unique chemical microenvironments for behaviour-driven innovations that pave the way to complex brain functions and elementary cognition. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, McKnight Brain Institute and Whitney laboratory, University of Florida, 9505 Ocean shore Blvd, St Augustine, FL 32080, USA
| | - Daria Y. Romanova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova Street, Moscow 117485, Russia
| | - Andrea B. Kohn
- Department of Neuroscience, McKnight Brain Institute and Whitney laboratory, University of Florida, 9505 Ocean shore Blvd, St Augustine, FL 32080, USA
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Kucharczyk MW, Derrien D, Dickenson AH, Bannister K. The Stage-Specific Plasticity of Descending Modulatory Controls in a Rodent Model of Cancer-Induced Bone Pain. Cancers (Basel) 2020; 12:cancers12113286. [PMID: 33172040 PMCID: PMC7716240 DOI: 10.3390/cancers12113286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/25/2020] [Accepted: 11/03/2020] [Indexed: 12/31/2022] Open
Abstract
Simple Summary The mechanisms that underlie pain resulting from metastatic bone disease remain elusive. This translates to a clinical and socioeconomic burden—targeted therapy is not possible, and patients do not receive adequate analgesic relief. The heterogeneous nature of metastatic bone disease complicates matters. Early stage cancers are molecularly very different to their late stage counterparts and so is the pain associated with early stage and advanced tumours. Thus, analgesic approaches should differ according to disease stage. In this article, we demonstrate that a unique form of brain inhibitory control responsible for the modulation of incoming pain signals at the level of the spinal cord changes with the progression of bone tumours. This corresponds with the degree of damage to the primary afferents innervating the cancerous tissue. Plasticity in the modulation of spinal neuronal activity by descending control pathways reveals a novel opportunity for targeting bone cancer pain in a stage-specific manner. Abstract Pain resulting from metastatic bone disease is a major unmet clinical need. Studying spinal processing in rodent models of cancer pain is desirable since the percept of pain is influenced in part by modulation at the level of the transmission system in the dorsal horn of the spinal cord. Here, a rodent model of cancer-induced bone pain (CIBP) was generated following syngeneic rat mammary gland adenocarcinoma cell injection in the tibia of male Sprague Dawley rats. Disease progression was classified as “early” or “late” stage according to bone destruction. Even though wakeful CIBP rats showed progressive mechanical hypersensitivity, subsequent in vivo electrophysiological measurement of mechanically evoked deep dorsal horn spinal neuronal responses revealed no change. Rather, a dynamic reorganization of spinal neuronal modulation by descending controls was observed, and this was maladaptive only in the early stage of CIBP. Interestingly, this latter observation corresponded with the degree of damage to the primary afferents innervating the cancerous tissue. Plasticity in the modulation of spinal neuronal activity by descending control pathways reveals a novel opportunity for targeting CIBP in a stage-specific manner. Finally, the data herein have translational potential since the descending control pathways measured are present also in humans.
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Affiliation(s)
- Mateusz Wojciech Kucharczyk
- Central Modulation of Pain Group, Wolfson Centre for Age-Related Diseases, King’s College London, London SE1 1UL, UK;
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK; (D.D.); (A.H.D.)
- Correspondence: ; Tel.: +44-20-7848-4617; Fax: +44-20-7848-6806
| | - Diane Derrien
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK; (D.D.); (A.H.D.)
| | - Anthony Henry Dickenson
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK; (D.D.); (A.H.D.)
| | - Kirsty Bannister
- Central Modulation of Pain Group, Wolfson Centre for Age-Related Diseases, King’s College London, London SE1 1UL, UK;
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Pacholko AG, Wotton CA, Bekar LK. Astrocytes-The Ultimate Effectors of Long-Range Neuromodulatory Networks? Front Cell Neurosci 2020; 14:581075. [PMID: 33192327 PMCID: PMC7554522 DOI: 10.3389/fncel.2020.581075] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/07/2020] [Indexed: 11/21/2022] Open
Abstract
It was long thought that astrocytes, given their lack of electrical signaling, were not involved in communication with neurons. However, we now know that one astrocyte on average maintains and regulates the extracellular neurotransmitter and potassium levels of more than 140,000 synapses, both excitatory and inhibitory, within their individual domains, and form a syncytium that can propagate calcium waves to affect distant cells via release of “gliotransmitters” such as glutamate, ATP, or adenosine. Neuromodulators can affect signal-to-noise and frequency transmission within cortical circuits by effects on inhibition, allowing for the filtering of relevant vs. irrelevant stimuli. Moreover, synchronized “resting” and desynchronized “activated” brain states are gated by short bursts of high-frequency neuromodulatory activity, highlighting the need for neuromodulation that is robust, rapid, and far-reaching. As many neuromodulators are released in a volume manner where degradation/uptake and the confines of the complex CNS limit diffusion distance, we ask the question—are astrocytes responsible for rapidly extending neuromodulator actions to every synapse? Neuromodulators are known to influence transitions between brain states, leading to control over plasticity, responses to salient stimuli, wakefulness, and sleep. These rapid and wide-spread state transitions demand that neuromodulators can simultaneously influence large and diverse regions in a manner that should be impossible given the limitations of simple diffusion. Intriguingly, astrocytes are ideally situated to amplify/extend neuromodulator effects over large populations of synapses given that each astrocyte can: (1) ensheath a large number of synapses; (2) release gliotransmitters (glutamate/ATP/adenosine) known to affect inhibition; (3) regulate extracellular potassium that can affect excitability and excitation/inhibition balance; and (4) express receptors for all neuromodulators. In this review article, we explore the hypothesis that astrocytes extend and amplify neuromodulatory influences on neuronal networks via alterations in calcium dynamics, the release of gliotransmitters, and potassium homeostasis. Given that neuromodulatory networks are at the core of our sleep-wake cycle and behavioral states, and determine how we interact with our environment, this review article highlights the importance of basic astrocyte function in homeostasis, general cognition, and psychiatric disorders.
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Affiliation(s)
- Anthony G Pacholko
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Caitlin A Wotton
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Lane K Bekar
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
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van den Burg EH, Hegoburu C. Modulation of expression of fear by oxytocin signaling in the central amygdala: From reduction of fear to regulation of defensive behavior style. Neuropharmacology 2020; 173:108130. [PMID: 32389750 DOI: 10.1016/j.neuropharm.2020.108130] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/28/2020] [Accepted: 05/03/2020] [Indexed: 12/17/2022]
Abstract
Many studies in preclinical animal models have described fear-reducing effects of the neuropeptide oxytocin in the central nucleus of the amygdala. However, recent studies have refined the role of oxytocin in the central amygdala, which may extend to the selection of an active defensive coping style in the face of immediate threat, and also fear-enhancing effects have been reported. On top of this, oxytocin enables the discrimination of unfamiliar conspecifics on the basis of their emotional state, which could allow for the selection of an appropriate coping style. This is in line with many observations that support the hypothesis that the precise outcome of oxytocin signaling in the central amygdala or other brain regions depends on the emotional or physiological state of an animal. In this review, we highlight a number of studies to exemplify the diverse effects oxytocin exerts on fear in the central amygdala of rodents. These are discussed in the context of the organization of the neural network within the central amygdala and in relation to the oxytocin-synthesizing neurons in the hypothalamus.
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Affiliation(s)
- Erwin H van den Burg
- Center for Psychiatric Neurosciences, Lausanne University Hospital Center (CHUV), Prilly, Lausanne, Switzerland.
| | - Chloé Hegoburu
- Center for Psychiatric Neurosciences, Lausanne University Hospital Center (CHUV), Prilly, Lausanne, Switzerland.
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Hernández-Carballo G, Ruíz-Luna EA, López-López G, Manjarrez E, Flores-Hernández J. Changes in Serotonin Modulation of Glutamate Currents in Pyramidal Offspring Cells of Rats Treated With 5-MT during Gestation. Brain Sci 2020; 10:E221. [PMID: 32276365 PMCID: PMC7225987 DOI: 10.3390/brainsci10040221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 11/16/2022] Open
Abstract
Changes in stimuli and feeding in pregnant mothers alter the behavior of offspring. Since behavior is mediated by brain activity, it is expected that postnatal changes occur at the level of currents, receptors or soma and dendrites structure and modulation. In this work, we explore at the mechanism level the effects on Sprague-Dawley rat offspring following the administration of serotonin (5-HT) agonist 5-methoxytryptamine (5-MT). We analyzed whether 5-HT affects the glutamate-activated (IGlut) and N-methyl-D-aspartate (NMDA)-activated currents (IGlut, INMDA) in dissociated pyramidal neurons from the prefrontal cortex (PFC). For this purpose, we performed voltage-clamp experiments on pyramidal neurons from layers V-VI of the PFC of 40-day-old offspring born from 5-MT-treated mothers at the gestational days (GD) 11 to 21. We found that the pyramidal-neurons from the PFC of offspring of mothers treated with 5-MT exhibit a significant increased reduction in both the IGlut and INMDA when 5-HT was administered. Our results suggest that the concentration increase of a neuromodulator during the gestation induces changes in its modulatory action over the offspring ionic currents during the adulthood thus contributing to possible psychiatric disorders.
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Affiliation(s)
- Gustavo Hernández-Carballo
- Instituto de Fisiología Benemérita Universidad Autónoma de Puebla, Puebla C.P.72570, Mexico; (G.H.-C.); (E.A.R.-L.); (E.M.)
| | - Evelyn A. Ruíz-Luna
- Instituto de Fisiología Benemérita Universidad Autónoma de Puebla, Puebla C.P.72570, Mexico; (G.H.-C.); (E.A.R.-L.); (E.M.)
| | - Gustavo López-López
- Facultad de Ciencias Químicas Benemérita Universidad Autónoma de Puebla, Puebla C.P.72570, Mexico;
| | - Elias Manjarrez
- Instituto de Fisiología Benemérita Universidad Autónoma de Puebla, Puebla C.P.72570, Mexico; (G.H.-C.); (E.A.R.-L.); (E.M.)
| | - Jorge Flores-Hernández
- Instituto de Fisiología Benemérita Universidad Autónoma de Puebla, Puebla C.P.72570, Mexico; (G.H.-C.); (E.A.R.-L.); (E.M.)
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Zhao HH, Du H, Cai Y, Liu C, Xie Z, Chen KC. Time-resolved quantification of the dynamic extracellular space in the brain: study of cortical spreading depression. J Neurophysiol 2019; 121:1735-1747. [PMID: 30786223 DOI: 10.1152/jn.00348.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Extracellular diffusion in the brain is customarily characterized by two parameters, the extracellular space (ECS) volume fraction α and the diffusion tortuosity λ. How these two parameters are temporarily modified and correlated in a physiological/pathological event remains unclear to date. Using tetramethylammonium (TMA+) as an ECS ion tracer in a newly updated iontophoretic sinusoidal method, we studied in this work the dynamic α(t) and λ(t) in rat somatosensory cortex during spreading depression (SD). Temporal variations of α(t) and λ(t), as evoked by SD, were obtained through analyses of the extracellular TMA+ diffusion waveform resulting from a sinusoidally modulated point source. Most of the time, cortical SD induced coordinated α(t) decreases and λ(t) increases. In rare occasions, SD induced sole decreases of α(t) with no changes in λ(t). The independent modulation of α(t) and λ(t) was neither associated with cortical anatomy nor with the specific shape of the SD field potential wave. Changes of α(t) and λ(t) often took place acutely at the onset of SD, followed by a more transient modulation. Compared with the prior iontophoretic methods of TMA+, the sinusoidal method provides time-resolved quantification of α(t) and λ(t) in relative terms but also raises a higher property requirement on the TMA+-selective microelectrode. The sinusoidal method could become a valuable tool in the studies of the dynamic ECS response in various brain events. NEW & NOTEWORTHY An iontophoretic sinusoidal method was applied to study the dynamic changes of two extracellular space parameters, the extracellular volume fraction α(t) and tortuosity λ(t), in the brain during cortical spreading depression. Both parameters showed coordinated (most often) and independent (rarely) modulations in spreading depression. The sinusoidal method is equally applicable to other acute pathological events and a valuable tool to study the functional role of extracellular space in brain events.
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Affiliation(s)
- Hui-Hui Zhao
- Multidisciplinary Research Center, Shantou University , Shantou, Guangdong , China
| | - Hong Du
- Multidisciplinary Research Center, Shantou University , Shantou, Guangdong , China
| | - Yujie Cai
- Multidisciplinary Research Center, Shantou University , Shantou, Guangdong , China
| | - Chao Liu
- Multidisciplinary Research Center, Shantou University , Shantou, Guangdong , China
| | - Zeyu Xie
- Neurosurgery Division, Second Affiliated Hospital of the School of Medicine, Shantou University , Shantou, Guangdong , China
| | - Kevin C Chen
- Multidisciplinary Research Center, Shantou University , Shantou, Guangdong , China.,Department of Biomedical Engineering, Shantou University , Shantou, Guangdong , China
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Coggan JS, Keller D, Calì C, Lehväslaiho H, Markram H, Schürmann F, Magistretti PJ. Norepinephrine stimulates glycogenolysis in astrocytes to fuel neurons with lactate. PLoS Comput Biol 2018; 14:e1006392. [PMID: 30161133 PMCID: PMC6160207 DOI: 10.1371/journal.pcbi.1006392] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/27/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022] Open
Abstract
The mechanism of rapid energy supply to the brain, especially to accommodate the heightened metabolic activity of excited states, is not well-understood. We explored the role of glycogen as a fuel source for neuromodulation using the noradrenergic stimulation of glia in a computational model of the neural-glial-vasculature ensemble (NGV). The detection of norepinephrine (NE) by the astrocyte and the coupled cAMP signal are rapid and largely insensitive to the distance of the locus coeruleus projection release sites from the glia, implying a diminished impact for volume transmission in high affinity receptor transduction systems. Glucosyl-conjugated units liberated from glial glycogen by NE-elicited cAMP second messenger transduction winds sequentially through the glycolytic cascade, generating robust increases in NADH and ATP before pyruvate is finally transformed into lactate. This astrocytic lactate is rapidly exported by monocarboxylate transporters to the associated neuron, demonstrating that the astrocyte-to-neuron lactate shuttle activated by glycogenolysis is a likely fuel source for neuromodulation and enhanced neural activity. Altogether, the energy supply for both astrocytes and neurons can be supplied rapidly by glycogenolysis upon neuromodulatory stimulus. Although efficient compared to computers, the human brain utilizes energy at 10-fold the rate of other organs by mass. How the brain is supplied with sufficient on-demand energy to support its activity in the absence of neuronal storage capacity remains unknown. Neurons are not capable of meeting their own energy requirements, instead energy supply in the brain is managed by an oligocellular cartel composed of neurons, glia and the local vasculature (NGV), wherein glia can provide the ergogenic metabolite lactate to the neuron in a process called the astrocyte-to-neuron shuttle (ANLS). The only means of energy storage in the brain is glycogen, a polymerized form of glucose that is localized largely to astrocytes, but its exact role and conditions of use are not clear. In this computational model we show that neuromodulatory stimulation by norepinephrine induces astrocytes to recover glucosyl subunits from glycogen for use in a glycolytic process that favors the production of lactate. The ATP and NADH produced support metabolism in the astrocyte while the lactate is exported to feed the neuron. Thus, rapid energy demands by both neurons and glia in a stimulated brain can be met by glycogen mobilization.
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Affiliation(s)
- Jay S. Coggan
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- * E-mail: (JSC); (PJM)
| | - Daniel Keller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Corrado Calì
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Heikki Lehväslaiho
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Felix Schürmann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Pierre J. Magistretti
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
- * E-mail: (JSC); (PJM)
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12
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Peineau S, Rabiant K, Pierrefiche O, Potier B. Synaptic plasticity modulation by circulating peptides and metaplasticity: Involvement in Alzheimer's disease. Pharmacol Res 2018; 130:385-401. [PMID: 29425728 DOI: 10.1016/j.phrs.2018.01.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/23/2018] [Accepted: 01/26/2018] [Indexed: 10/18/2022]
Abstract
Synaptic plasticity is a cellular process involved in learning and memory whose alteration in its two main forms (Long Term Depression (LTD) and Long Term Potentiation (LTP)), is observed in most brain pathologies, including neurodegenerative disorders such as Alzheimer's disease (AD). In humans, AD is associated at the cellular level with neuropathological lesions composed of extracellular deposits of β-amyloid (Aβ) protein aggregates and intracellular neurofibrillary tangles, cellular loss, neuroinflammation and a general brain homeostasis dysregulation. Thus, a dramatic synaptic environment perturbation is observed in AD patients, involving changes in brain neuropeptides, cytokines, growth factors or chemokines concentration and diffusion. Studies performed in animal models demonstrate that these circulating peptides strongly affect synaptic functions and in particular synaptic plasticity. Besides this neuromodulatory action of circulating peptides, other synaptic plasticity regulation mechanisms such as metaplasticity are altered in AD animal models. Here, we will review new insights into the study of synaptic plasticity regulatory/modulatory mechanisms which could influence the process of synaptic plasticity in the context of AD with a particular attention to the role of metaplasticity and peptide dependent neuromodulation.
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Affiliation(s)
- Stéphane Peineau
- GRAP UMR1247, INSERM, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France; Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK.
| | - Kevin Rabiant
- GRAP UMR1247, INSERM, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France
| | - Olivier Pierrefiche
- GRAP UMR1247, INSERM, Centre Universitaire de Recherche en Santé, Université de Picardie Jules Verne, Amiens, France.
| | - Brigitte Potier
- Laboratoire Aimé Cotton, CNRS-ENS UMR9188, Université Paris-Sud, Orsay, France.
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13
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Ferguson BS, Rogatzki MJ, Goodwin ML, Kane DA, Rightmire Z, Gladden LB. Lactate metabolism: historical context, prior misinterpretations, and current understanding. Eur J Appl Physiol 2018; 118:691-728. [PMID: 29322250 DOI: 10.1007/s00421-017-3795-6] [Citation(s) in RCA: 196] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 12/22/2017] [Indexed: 02/07/2023]
Abstract
Lactate (La-) has long been at the center of controversy in research, clinical, and athletic settings. Since its discovery in 1780, La- has often been erroneously viewed as simply a hypoxic waste product with multiple deleterious effects. Not until the 1980s, with the introduction of the cell-to-cell lactate shuttle did a paradigm shift in our understanding of the role of La- in metabolism begin. The evidence for La- as a major player in the coordination of whole-body metabolism has since grown rapidly. La- is a readily combusted fuel that is shuttled throughout the body, and it is a potent signal for angiogenesis irrespective of oxygen tension. Despite this, many fundamental discoveries about La- are still working their way into mainstream research, clinical care, and practice. The purpose of this review is to synthesize current understanding of La- metabolism via an appraisal of its robust experimental history, particularly in exercise physiology. That La- production increases during dysoxia is beyond debate, but this condition is the exception rather than the rule. Fluctuations in blood [La-] in health and disease are not typically due to low oxygen tension, a principle first demonstrated with exercise and now understood to varying degrees across disciplines. From its role in coordinating whole-body metabolism as a fuel to its role as a signaling molecule in tumors, the study of La- metabolism continues to expand and holds potential for multiple clinical applications. This review highlights La-'s central role in metabolism and amplifies our understanding of past research.
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Affiliation(s)
- Brian S Ferguson
- College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Matthew J Rogatzki
- Department of Health and Exercise Science, Appalachian State University, Boone, NC, USA
| | - Matthew L Goodwin
- Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA.,Huntsman Cancer Institute, Salt Lake City, UT, USA
| | - Daniel A Kane
- Department of Human Kinetics, St. Francis Xavier University, Antigonish, Canada
| | - Zachary Rightmire
- School of Kinesiology, Auburn University, 301 Wire Road, Auburn, AL, 36849, USA
| | - L Bruce Gladden
- School of Kinesiology, Auburn University, 301 Wire Road, Auburn, AL, 36849, USA.
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14
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van der Velden L, Vinck M, Werkman TR, Wadman WJ. Tuning of Neuronal Interactions in the Lateral Ventral Tegmental Area by Dopamine Sensitivity. Neuroscience 2017; 366:62-69. [PMID: 29037597 DOI: 10.1016/j.neuroscience.2017.10.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 12/12/2022]
Abstract
The Ventral Tegmental Area (VTA) contains a considerable population of rhythmically firing dopaminergic neurons, which are influenced by auto-inhibition due to extra-synaptic dopamine release resulting in volume transmission. Using a Multi-Electrode-Array we simultaneously recorded in vitro from multiple VTA dopamine neurons in the rat and studied their mutual interactions. We observed that the dopamine sensitivity (EC50) of the neurons (i.e. the relation between dopamine concentration and firing rate) was quite variable within the recorded population. The interactions between pairs of neurons were quantified using the Granger causality. We found that the dopamine sensitivity determined the role of a neuron in the local VTA population. Highly sensitive neurons became followers (of the population rhythm), whereas less sensitive dopamine neurons played a more leading role. This was confirmed by the application of sulpiride which reduces the dopamine sensitivity of all neurons through competition and abolishes the structure in the interactions. These findings imply that therapeutics, which have an easy to understand effect on firing rate, could have a more complicated effect on the functional organization of the local VTA population, through volume transmission principles.
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Affiliation(s)
- Luuk van der Velden
- University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Martin Vinck
- Ernst Strüngmann Institute, Deutschordenstraße 46, 60528 Frankfurt am Main, Germany
| | - Taco R Werkman
- University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Wytse J Wadman
- University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands.
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15
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The brain interstitial system: Anatomy, modeling, in vivo measurement, and applications. Prog Neurobiol 2017; 157:230-246. [DOI: 10.1016/j.pneurobio.2015.12.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/18/2015] [Accepted: 12/02/2015] [Indexed: 01/01/2023]
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16
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Liu Z, Huang Y, Liu L, Zhang L. Inhibitions of PKC and CaMK-II synergistically rescue ischemia-induced astrocytic dysfunction. Neurosci Lett 2017; 657:199-203. [DOI: 10.1016/j.neulet.2017.08.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 08/02/2017] [Accepted: 08/07/2017] [Indexed: 01/29/2023]
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17
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Moldavan M, Cravetchi O, Allen CN. GABA transporters regulate tonic and synaptic GABA A receptor-mediated currents in the suprachiasmatic nucleus neurons. J Neurophysiol 2017; 118:3092-3106. [PMID: 28855287 DOI: 10.1152/jn.00194.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 11/22/2022] Open
Abstract
GABA is a principal neurotransmitter in the hypothalamic suprachiasmatic nucleus (SCN) that contributes to intercellular communication between individual circadian oscillators within the SCN network and the stability and precision of the circadian rhythms. GABA transporters (GAT) regulate the extracellular GABA concentration and modulate GABAA receptor (GABAAR)-mediated currents. GABA transport inhibitors were applied to study how GABAAR-mediated currents depend on the expression and function of GAT. Nipecotic acid inhibits GABA transport and induced an inward tonic current in concentration-dependent manner during whole cell patch-clamp recordings from SCN neurons. Application of either the selective GABA transporter 1 (GAT1) inhibitors NNC-711 or SKF-89976A, or the GABA transporter 3 (GAT3) inhibitor SNAP-5114, produced only small changes of the baseline current. Coapplication of GAT1 and GAT3 inhibitors induced a significant GABAAR-mediated tonic current that was blocked by gabazine. GAT inhibitors decreased the amplitude and decay time constant and increased the rise time of spontaneous GABAAR-mediated postsynaptic currents. However, inhibition of GAT did not alter the expression of either GAT1 or GAT3 in the hypothalamus. Thus GAT1 and GAT3 functionally complement each other to regulate the extracellular GABA concentration and GABAAR-mediated synaptic and tonic currents in the SCN. Coapplication of SKF-89976A and SNAP-5114 (50 µM each) significantly reduced the circadian period of Per1 expression in the SCN by 1.4 h. Our studies demonstrate that GAT are important regulators of GABAAR-mediated currents and the circadian clock in the SCN.NEW & NOTEWORTHY In the suprachiasmatic nucleus (SCN), the GABA transporters GAT1 and GAT3 are expressed in astrocytes. Inhibition of these GABA transporters increased a tonic GABA current and reduced the circadian period of Per1 expression in SCN neurons. GAT1 and GAT3 showed functional cooperativity: inhibition of one GAT increased the activity but not the expression of the other. Our data demonstrate that GABA transporters are important regulators of GABAA receptor-mediated currents and the circadian clock.
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Affiliation(s)
- Michael Moldavan
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon; and
| | - Olga Cravetchi
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon; and
| | - Charles N Allen
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon; and .,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon
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18
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Thamm M, Scholl C, Reim T, Grübel K, Möller K, Rössler W, Scheiner R. Neuronal distribution of tyramine and the tyramine receptor AmTAR1 in the honeybee brain. J Comp Neurol 2017; 525:2615-2631. [DOI: 10.1002/cne.24228] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 01/28/2023]
Affiliation(s)
- Markus Thamm
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Christina Scholl
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Tina Reim
- Animal Physiology, Institute for Biochemistry and Biology, University of PotsdamPotsdam Germany
| | - Kornelia Grübel
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Karin Möller
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Wolfgang Rössler
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Ricarda Scheiner
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
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19
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Khozhai LI. Expression of serotonin transporter in the dorsal raphe nucleus during the early postnatal period in the normal state and under prenatal deficiency of the serotonergic system in rats. J EVOL BIOCHEM PHYS+ 2016. [DOI: 10.1134/s0022093016010087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Hirase H, Iwai Y, Takata N, Shinohara Y, Mishima T. Volume transmission signalling via astrocytes. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130604. [PMID: 25225097 PMCID: PMC4173289 DOI: 10.1098/rstb.2013.0604] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The influence of astrocytes on synaptic function has been increasingly studied, owing to the discovery of both gliotransmission and morphological ensheathment of synapses. While astrocytes exhibit at best modest membrane potential fluctuations, activation of G-protein coupled receptors (GPCRs) leads to a prominent elevation of intracellular calcium which has been reported to correlate with gliotransmission. In this review, the possible role of astrocytic GPCR activation is discussed as a trigger to promote synaptic plasticity, by affecting synaptic receptors through gliotransmitters. Moreover, we suggest that volume transmission of neuromodulators could be a biological mechanism to activate astrocytic GPCRs and thereby to switch synaptic networks to the plastic mode during states of attention in cerebral cortical structures.
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Affiliation(s)
- Hajime Hirase
- Laboratory for Neuron-Glia Circuitry, RIKEN Brain Science Institute, Wako, Saitama, Japan Saitama University Brain Science Institute, Saitama, Saitama, Japan
| | - Youichi Iwai
- Laboratory for Neuron-Glia Circuitry, RIKEN Brain Science Institute, Wako, Saitama, Japan
| | - Norio Takata
- Laboratory for Neuron-Glia Circuitry, RIKEN Brain Science Institute, Wako, Saitama, Japan Department of Neuropsychiatry, School of Medicine, Keio University, Shinjuku, Tokyo, Japan
| | - Yoshiaki Shinohara
- Laboratory for Neuron-Glia Circuitry, RIKEN Brain Science Institute, Wako, Saitama, Japan
| | - Tsuneko Mishima
- Laboratory for Neuron-Glia Circuitry, RIKEN Brain Science Institute, Wako, Saitama, Japan
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21
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Huang L, Zhao S, Lu W, Guan S, Zhu Y, Wang JH. Acidosis-Induced Dysfunction of Cortical GABAergic Neurons through Astrocyte-Related Excitotoxicity. PLoS One 2015; 10:e0140324. [PMID: 26474076 PMCID: PMC4608795 DOI: 10.1371/journal.pone.0140324] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/24/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Acidosis impairs cognitions and behaviors presumably by acidification-induced changes in neuronal metabolism. Cortical GABAergic neurons are vulnerable to pathological factors and their injury leads to brain dysfunction. How acidosis induces GABAergic neuron injury remains elusive. As the glia cells and neurons interact each other, we intend to examine the role of the astrocytes in acidosis-induced GABAergic neuron injury. RESULTS Experiments were done at GABAergic cells and astrocytes in mouse cortical slices. To identify astrocytic involvement in acidosis-induced impairment, we induced the acidification in single GABAergic neuron by infusing proton intracellularly or in both neurons and astrocytes by using proton extracellularly. Compared the effects of intracellular acidification and extracellular acidification on GABAergic neurons, we found that their active intrinsic properties and synaptic outputs appeared more severely impaired in extracellular acidosis than intracellular acidosis. Meanwhile, extracellular acidosis deteriorated glutamate transporter currents on the astrocytes and upregulated excitatory synaptic transmission on the GABAergic neurons. Moreover, the antagonists of glutamate NMDA-/AMPA-receptors partially reverse extracellular acidosis-induced injury in the GABAergic neurons. CONCLUSION Our studies suggest that acidosis leads to the dysfunction of cortical GABAergic neurons by astrocyte-mediated excitotoxicity, in addition to their metabolic changes as indicated previously.
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Affiliation(s)
- Li Huang
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Shidi Zhao
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Wei Lu
- Collaborative Innovation Center for Neurodegenerative Disorders in Shandong, Qingdao University, Medical College, 38 Dengzhou, Shandong China 266021
| | - Sudong Guan
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Yan Zhu
- Department of Pathophysiology, Bengbu Medical College, Bengbu Anhui, China 233000
| | - Jin-Hui Wang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing China 100101
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22
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Otero-García M, Agustín-Pavón C, Lanuza E, Martínez-García F. Distribution of oxytocin and co-localization with arginine vasopressin in the brain of mice. Brain Struct Funct 2015; 221:3445-73. [PMID: 26388166 DOI: 10.1007/s00429-015-1111-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/09/2015] [Indexed: 12/19/2022]
Abstract
Oxytocin (OT) and vasopressin (AVP) play a major role in social behaviours. Mice have become the species of choice for neurobiology of social behaviour due to identification of mouse pheromones and the advantage of genetically modified mice. However, neuroanatomical data on nonapeptidergic systems in mice are fragmentary, especially concerning the central distribution of OT. Therefore, we analyse the immunoreactivity for OT and its neurophysin in the brain of male and female mice (strain CD1). Further, we combine immunofluorescent detection of OT and AVP to locate cells co-expressing both peptides and their putative axonal processes. The results indicate that OT is present in cells of the neurosecretory paraventricular (Pa) and supraoptic hypothalamic nuclei (SON). From the anterior SON, OTergic cells extend into the medial amygdala, where a sparse cell population occupies its ventral anterior and posterior divisions. Co-expression of OT and AVP in these nuclei is rare. Moreover, a remarkable OTergic cell group is found near the ventral bed nucleus of the stria terminalis (BST), distributed between the anterodorsal preoptic nucleus and the nucleus of anterior commissure (ADP/AC). This cell group, the rostral edge of the Pa and the periventricular hypothalamus display frequent OT + AVP double labelling, with a general dominance of OT over AVP immunoreactivity. Fibres with similar immunoreactivity profile innervate the accumbens shell and core, central amygdala and portions of the intervening BST. These data, together with data in the literature on rats, suggest that the projections of ADP/AC nonapeptidergic cells onto these brain centres could promote pup-motivated behaviours and inhibit pup avoidance during motherhood.
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Affiliation(s)
- Marcos Otero-García
- Departaments de Biologia Cel·lular i de Biologia Funcional, Facultat de Ciències Biològiques, Universitat de València, València, Spain
| | - Carmen Agustín-Pavón
- Lab. of Functional Neuroanatomy (NeuroFun), Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain
| | - Enrique Lanuza
- Departaments de Biologia Cel·lular i de Biologia Funcional, Facultat de Ciències Biològiques, Universitat de València, València, Spain
| | - Fernando Martínez-García
- Lab. of Functional Neuroanatomy (NeuroFun), Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain.
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23
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Stern JE. Neuroendocrine-autonomic integration in the paraventricular nucleus: novel roles for dendritically released neuropeptides. J Neuroendocrinol 2015; 27:487-97. [PMID: 25546497 PMCID: PMC4447596 DOI: 10.1111/jne.12252] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/09/2014] [Accepted: 12/18/2014] [Indexed: 12/21/2022]
Abstract
Communication between pairs of neurones in the central nervous system typically involves classical 'hard-wired' synaptic transmission, characterised by high temporal and spatial precision. Over the last two decades, however, knowledge regarding the repertoire of communication modalities used in the brain has notably expanded to include less conventional forms, characterised by a diffuse and less temporally precise transfer of information. These forms are best suited to mediate communication among entire neuronal populations, now recognised to be a fundamental process in the brain for the generation of complex behaviours. In response to an osmotic stressor, the hypothalamic paraventricular nucleus (PVN) generates a multimodal homeostatic response that involves orchestrated neuroendocrine (i.e. systemic release of vasopressin) and autonomic (i.e. sympathetic outflow to the kidneys) components. The precise mechanisms that underlie interpopulation cross-talk between these two distinct neuronal populations, however, remain largely unknown. The present review summarises and discusses a series of recent studies that have identified the dendritic release of neuropeptides as a novel interpopulation signalling modality in the PVN. A current working model is described in which it is proposed that the activity-dependent dendritic release of vasopressin from neurosecretory neurones in the PVN acts in a diffusible manner to increase the activity of distant presympathetic neurones, resulting in an integrated sympathoexcitatory population response, particularly within the context of a hyperosmotic challenge. The cellular mechanism underlying this novel form of intercellular communication, as well as its physiological and pathophysiological implications, is discussed.
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Affiliation(s)
- J E Stern
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
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24
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Garcia-Munoz M, Lopez-Huerta VG, Carrillo-Reid L, Arbuthnott GW. Extrasynaptic glutamate NMDA receptors: key players in striatal function. Neuropharmacology 2014; 89:54-63. [PMID: 25239809 DOI: 10.1016/j.neuropharm.2014.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/26/2014] [Accepted: 09/06/2014] [Indexed: 10/24/2022]
Abstract
N-methyl-D-aspartate receptors (NMDAR) are crucial for the function of excitatory neurotransmission and are present at the synapse and on the extrasynaptic membrane. The major nucleus of the basal ganglia, striatum, receives a large glutamatergic excitatory input carrying information about movements and associated sensory stimulation for its proper function. Such bombardment of glutamate synaptic release results in a large extracellular concentration of glutamate that can overcome the neuronal and glial uptake homeostatic systems therefore allowing the stimulation of extrasynaptic glutamate receptors. Here we have studied the participation of their extrasynaptic type in cortically evoked responses or in the presence of NMDARs stimulation. We report that extrasynaptic NMDAR blocker memantine, reduced in a dose-dependent manner cortically induced NMDA excitatory currents in striatal neurons (recorded in zero-Mg(++) plus DNQX 10 μM). Moreover, memantine (2-4 μM) significantly reduced the NMDAR-dependent membrane potential oscillations called up and down states. Recordings of neuronal striatal networks with a fluorescent calcium indicator or with multielectrode arrays (MEA) also showed that memantine reduced in a dose-dependent manner, NMDA-induced excitatory currents and network behavior. We used multielectrode arrays (MEA) to grow segregated cortical and striatal neurons. Once synaptic contacts were developed (>21DIV) recordings of extracellular activity confirmed the cortical drive of spontaneous synchronous discharges in both compartments. After severing connections between compartments, active striatal neurons in the presence of memantine (1 μM) and CNQX (10 μM) were predominantly fast spiking interneurons (FSI). The significance of extrasynaptic receptors in the regulation of striatal function and neuronal network activity is evident.
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Affiliation(s)
- Marianela Garcia-Munoz
- Brain Mechanisms for Behaviour Unit, Okinawa Institute of Science and Technology Graduate University, Japan.
| | - Violeta G Lopez-Huerta
- Brain Mechanisms for Behaviour Unit, Okinawa Institute of Science and Technology Graduate University, Japan.
| | - Luis Carrillo-Reid
- Brain Mechanisms for Behaviour Unit, Okinawa Institute of Science and Technology Graduate University, Japan; Department of Biological Sciences, Columbia University, NY, USA.
| | - Gordon W Arbuthnott
- Brain Mechanisms for Behaviour Unit, Okinawa Institute of Science and Technology Graduate University, Japan.
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25
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Agster KL, Mejias-Aponte CA, Clark BD, Waterhouse BD. Evidence for a regional specificity in the density and distribution of noradrenergic varicosities in rat cortex. J Comp Neurol 2013; 521:2195-207. [PMID: 23184811 PMCID: PMC4529674 DOI: 10.1002/cne.23270] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 11/09/2012] [Accepted: 11/13/2012] [Indexed: 11/10/2022]
Abstract
The brainstem nucleus locus coeruleus (LC) is the sole source of norepinephrine (NE)-containing fibers in the mammalian cortex. Previous studies suggest that the density of noradrenergic fibers in rat is relatively uniform across cortical regions and that cells in the nucleus discharge en masse. This implies that activation of the LC results in equivalent release of NE throughout the cortex. However, it is possible that there could be differences in the density of axonal varicosities across regions, and that these differences, rather than a difference in fiber density, may contribute to the regulation of NE efflux. Quantification of dopamine β-hydroxylase (DβH)-immunostained varicosities was performed on several cortical regions and in the ventral posterior medial (VPM) thalamus by using unbiased sampling methods. The density of DβH varicosities is greater in the prefrontal cortex than in motor, somatosensory, or piriform cortices, greater in superficial than in deep layers of cortex, and greater in the VPM than in the somatosensory cortex. Our results provide anatomical evidence for non-uniform release of NE across functionally discrete cortical regions. This morphology may account for a differential, region-specific, impact of LC output on different cortical areas.
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Affiliation(s)
- Kara L. Agster
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | | | - Brian D. Clark
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Barry D. Waterhouse
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
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26
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Goyal RK, Chaudhury A. Structure activity relationship of synaptic and junctional neurotransmission. Auton Neurosci 2013; 176:11-31. [PMID: 23535140 PMCID: PMC3677731 DOI: 10.1016/j.autneu.2013.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 12/28/2012] [Accepted: 02/18/2013] [Indexed: 12/18/2022]
Abstract
Chemical neurotransmission may include transmission to local or remote sites. Locally, contact between 'bare' portions of the bulbous nerve terminal termed a varicosity and the effector cell may be in the form of either synapse or non-synaptic contact. Traditionally, all local transmissions between nerves and effector cells are considered synaptic in nature. This is particularly true for communication between neurons. However, communication between nerves and other effectors such as smooth muscles has been described as nonsynaptic or junctional in nature. Nonsynaptic neurotransmission is now also increasingly recognized in the CNS. This review focuses on the relationship between structure and function that orchestrate synaptic and junctional neurotransmissions. A synapse is a specialized focal contact between the presynaptic active zone capable of ultrafast release of soluble transmitters and the postsynaptic density that cluster ionotropic receptors. The presynaptic and the postsynaptic areas are separated by the 'closed' synaptic cavity. The physiological hallmark of the synapse is ultrafast postsynaptic potentials lasting milliseconds. In contrast, junctions are juxtapositions of nerve terminals and the effector cells without clear synaptic specializations and the junctional space is 'open' to the extracellular space. Based on the nature of the transmitters, postjunctional receptors and their separation from the release sites, the junctions can be divided into 'close' and 'wide' junctions. Functionally, the 'close' and the 'wide' junctions can be distinguished by postjunctional potentials lasting ~1s and tens of seconds, respectively. Both synaptic and junctional communications are common between neurons; however, junctional transmission is the rule at many neuro-non-neural effectors.
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Affiliation(s)
- Raj K Goyal
- Center for Swallowing and Motility Disorders, GI Division, VA Boston Healthcare System and Harvard Medical School, Boston, USA.
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Wardill TJ, Gonzalez-Bellido PT, Crook RJ, Hanlon RT. Neural control of tuneable skin iridescence in squid. Proc Biol Sci 2012; 279:4243-52. [PMID: 22896651 DOI: 10.1098/rspb.2012.1374] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fast dynamic control of skin coloration is rare in the animal kingdom, whether it be pigmentary or structural. Iridescent structural coloration results when nanoscale structures disrupt incident light and selectively reflect specific colours. Unlike animals with fixed iridescent coloration (e.g. butterflies), squid iridophores (i.e. aggregations of iridescent cells in the skin) produce dynamically tuneable structural coloration, as exogenous application of acetylcholine (ACh) changes the colour and brightness output. Previous efforts to stimulate iridophores neurally or to identify the source of endogenous ACh were unsuccessful, leaving researchers to question the activation mechanism. We developed a novel neurophysiological preparation in the squid Doryteuthis pealeii and demonstrated that electrical stimulation of neurons in the skin shifts the spectral peak of the reflected light to shorter wavelengths (greater than 145 nm) and increases the peak reflectance (greater than 245%) of innervated iridophores. We show ACh is released within the iridophore layer and that extensive nerve branching is seen within the iridophore. The dynamic colour shift is significantly faster (17 s) than the peak reflectance increase (32 s), revealing two distinct mechanisms. Responses from a structurally altered preparation indicate that the reflectin protein condensation mechanism explains peak reflectance change, while an undiscovered mechanism causes the fast colour shift.
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Affiliation(s)
- T J Wardill
- Program in Sensory Physiology and Behavior, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA.
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Fuxe K, Borroto-Escuela DO, Romero-Fernandez W, Diaz-Cabiale Z, Rivera A, Ferraro L, Tanganelli S, Tarakanov AO, Garriga P, Narváez JA, Ciruela F, Guescini M, Agnati LF. Extrasynaptic neurotransmission in the modulation of brain function. Focus on the striatal neuronal-glial networks. Front Physiol 2012; 3:136. [PMID: 22675301 PMCID: PMC3366473 DOI: 10.3389/fphys.2012.00136] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Accepted: 04/23/2012] [Indexed: 12/20/2022] Open
Abstract
Extrasynaptic neurotransmission is an important short distance form of volume transmission (VT) and describes the extracellular diffusion of transmitters and modulators after synaptic spillover or extrasynaptic release in the local circuit regions binding to and activating mainly extrasynaptic neuronal and glial receptors in the neuroglial networks of the brain. Receptor-receptor interactions in G protein-coupled receptor (GPCR) heteromers play a major role, on dendritic spines and nerve terminals including glutamate synapses, in the integrative processes of the extrasynaptic signaling. Heteromeric complexes between GPCR and ion-channel receptors play a special role in the integration of the synaptic and extrasynaptic signals. Changes in extracellular concentrations of the classical synaptic neurotransmitters glutamate and GABA found with microdialysis is likely an expression of the activity of the neuron-astrocyte unit of the brain and can be used as an index of VT-mediated actions of these two neurotransmitters in the brain. Thus, the activity of neurons may be functionally linked to the activity of astrocytes, which may release glutamate and GABA to the extracellular space where extrasynaptic glutamate and GABA receptors do exist. Wiring transmission (WT) and VT are fundamental properties of all neurons of the CNS but the balance between WT and VT varies from one nerve cell population to the other. The focus is on the striatal cellular networks, and the WT and VT and their integration via receptor heteromers are described in the GABA projection neurons, the glutamate, dopamine, 5-hydroxytryptamine (5-HT) and histamine striatal afferents, the cholinergic interneurons, and different types of GABA interneurons. In addition, the role in these networks of VT signaling of the energy-dependent modulator adenosine and of endocannabinoids mainly formed in the striatal projection neurons will be underlined to understand the communication in the striatal cellular networks.
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Affiliation(s)
- Kjell Fuxe
- Department of Neuroscience, Karolinska InstitutetStockholm, Sweden
| | | | | | - Zaida Diaz-Cabiale
- Department of Physiology, School of Medicine, University of MálagaMálaga, Spain
| | - Alicia Rivera
- Department of Cell Biology, Faculty of Sciences, University of MálagaMálaga, Spain
| | - Luca Ferraro
- Pharmacology Section, Department of Clinical and Experimental Medicine, University of FerraraFerrara, Italy
| | - Sergio Tanganelli
- Pharmacology Section, Department of Clinical and Experimental Medicine, University of FerraraFerrara, Italy
| | - Alexander O. Tarakanov
- Russian Academy of Sciences, St. Petersburg Institute for Informatics and AutomationSaint Petersburg, Russia
| | - Pere Garriga
- Departament d’Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de CatalunyaBarcelona, Spain
| | - José Angel Narváez
- Department of Physiology, School of Medicine, University of MálagaMálaga, Spain
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Universitat de BarcelonaBarcelona, Spain
| | - Michele Guescini
- Department of Biomolecular Sciences, University of Urbino “CarloBo”Urbino, Italy
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Brain–spinal cord neural circuits controlling male sexual function and behavior. Neurosci Res 2012; 72:103-16. [DOI: 10.1016/j.neures.2011.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/14/2011] [Accepted: 10/25/2011] [Indexed: 01/10/2023]
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Nitzan-Luques A, Devor M, Tal M. Genotype-selective phenotypic switch in primary afferent neurons contributes to neuropathic pain. Pain 2011; 152:2413-2426. [PMID: 21872992 DOI: 10.1016/j.pain.2011.07.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 07/06/2011] [Accepted: 07/20/2011] [Indexed: 12/23/2022]
Abstract
Pain is normally mediated by nociceptive Aδ and C fibers, while Aβ fibers signal touch. However, after nerve injury, Aβ fibers may signal pain. Using a genetic model, we tested the hypothesis that phenotypic switching in neurotransmitters expressed by Aβ afferents might account for heritable differences in neuropathic pain behavior. The study examined selection-line rats in which one line, high autotomy (HA), shows higher levels of spontaneous pain in the neuroma neuropathy model, and of tactile allodynia in the spinal nerve ligation (SNL) model, than the companion low autotomy (LA) line. Changes in calcitonin gene-related peptide (CGRP) and Substance P expression were evaluated immunohistochemically in L4 and L5 dorsal root ganglia 7 days after SNL surgery. Expression of CGRP was decreased in axotomized small- and medium-diameter neurons in both rat lines. However, in HA but not in LA rats, there was a tenfold increase in CGRP immunoreactivity (CGRP-IR) in large-diameter neurons. Corresponding changes in CGRP-IR in axon terminals in the nucleus gracilis were also seen. Finally, there were indications of enhanced CGRP neurotransmission in deep laminae of the dorsal horn. Substance P immunoreactivity was also upregulated in large-diameter neurons, but this change was similar in the 2 lines. Our findings suggest that phenotypic switching contributes to the heritable difference in pain behavior in HA vs LA rats. Specifically, we propose that in HA rats, but less so in LA rats, injured, spontaneously active Aβ afferents both directly drive CGRP-sensitive central nervous system pain-signaling neurons and also trigger and maintain central sensitization, hence generating spontaneous pain and tactile allodynia.
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Affiliation(s)
- Adi Nitzan-Luques
- Department of Medical Neurobiology, Faculties of Medicine and Dentistry, The Hebrew University of Jerusalem, Jerusalem, Israel Department of Cell and Developmental Biology, Institute of Life Science, Faculty of Natural Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem, Israel
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Potjans W, Morrison A, Diesmann M. Enabling functional neural circuit simulations with distributed computing of neuromodulated plasticity. Front Comput Neurosci 2010; 4:141. [PMID: 21151370 PMCID: PMC2996144 DOI: 10.3389/fncom.2010.00141] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 09/15/2010] [Indexed: 11/13/2022] Open
Abstract
A major puzzle in the field of computational neuroscience is how to relate system-level learning in higher organisms to synaptic plasticity. Recently, plasticity rules depending not only on pre- and post-synaptic activity but also on a third, non-local neuromodulatory signal have emerged as key candidates to bridge the gap between the macroscopic and the microscopic level of learning. Crucial insights into this topic are expected to be gained from simulations of neural systems, as these allow the simultaneous study of the multiple spatial and temporal scales that are involved in the problem. In particular, synaptic plasticity can be studied during the whole learning process, i.e., on a time scale of minutes to hours and across multiple brain areas. Implementing neuromodulated plasticity in large-scale network simulations where the neuromodulatory signal is dynamically generated by the network itself is challenging, because the network structure is commonly defined purely by the connectivity graph without explicit reference to the embedding of the nodes in physical space. Furthermore, the simulation of networks with realistic connectivity entails the use of distributed computing. A neuromodulated synapse must therefore be informed in an efficient way about the neuromodulatory signal, which is typically generated by a population of neurons located on different machines than either the pre- or post-synaptic neuron. Here, we develop a general framework to solve the problem of implementing neuromodulated plasticity in a time-driven distributed simulation, without reference to a particular implementation language, neuromodulator, or neuromodulated plasticity mechanism. We implement our framework in the simulator NEST and demonstrate excellent scaling up to 1024 processors for simulations of a recurrent network incorporating neuromodulated spike-timing dependent plasticity.
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Affiliation(s)
- Wiebke Potjans
- Institute of Neuroscience and Medicine (INM-6), Computational and Systems Neuroscience, Research Center Jülich Jülich, Germany
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Brezina V. Beyond the wiring diagram: signalling through complex neuromodulator networks. Philos Trans R Soc Lond B Biol Sci 2010; 365:2363-74. [PMID: 20603357 PMCID: PMC2894954 DOI: 10.1098/rstb.2010.0105] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
During the computations performed by the nervous system, its 'wiring diagram'--the map of its neurons and synaptic connections--is dynamically modified and supplemented by multiple actions of neuromodulators that can be so complex that they can be thought of as constituting a biochemical network that combines with the neuronal network to perform the computation. Thus, the neuronal wiring diagram alone is not sufficient to specify, and permit us to understand, the computation that underlies behaviour. Here I review how such modulatory networks operate, the problems that their existence poses for the experimental study and conceptual understanding of the computations performed by the nervous system, and how these problems may perhaps be solved and the computations understood by considering the structural and functional 'logic' of the modulatory networks.
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Affiliation(s)
- Vladimir Brezina
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, USA.
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Preferential localization of muscarinic M1 receptor on dendritic shaft and spine of cortical pyramidal cells and its anatomical evidence for volume transmission. J Neurosci 2010; 30:4408-18. [PMID: 20335477 DOI: 10.1523/jneurosci.5719-09.2010] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Acetylcholine (ACh) plays important roles for higher brain functions, including arousal, attention, and cognition. These effects are mediated largely by muscarinic acetylcholine receptors (mAChRs). However, it remains inconclusive whether the mode of ACh-mAChR signaling is synaptic, so-called "wired," transmission mediated by ACh released into the synaptic cleft, or nonsynaptic, so-called "volume," transmission by ambient ACh. To address this issue, we examined cellular and subcellular distribution of M(1), the most predominant mAChR subtype in the cerebral cortex and hippocampus, and pursued its anatomical relationship with cholinergic varicosities in these regions of adult mice. M(1) was highly expressed in glutamatergic pyramidal neurons, whereas it was low or undetectable in various GABAergic interneuron subtypes. M(1) was preferentially distributed on the extrasynaptic membrane of pyramidal cell dendrites and spines. Cholinergic varicosities often made direct contact to pyramidal cell dendrites and synapses. At such contact sites, however, synapse-like specialization was infrequent, and no particular accumulation was found at around contact sites for both M(1) and presynpatic active zone protein Bassoon. These features contrasted with those of the glutamatergic system, in which AMPA receptor GluA2 and metabotropic receptor mGluR5 were recruited to the synaptic or perisynaptic membrane, respectively, and Bassoon was highly accumulated in the presynaptic terminals. These results suggest that M(1) is so positioned to sense ambient ACh released from cholinergic varicosities at variable distances, and to enhance the synaptic efficacy and excitability of pyramidal cells. These molecular-anatomical arrangements will provide the evidence for volume transmission, at least in M(1)-mediated cortical cholinergic signaling.
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Kaushalya SK, Desai R, Arumugam S, Ghosh H, Balaji J, Maiti S. Three-photon microscopy shows that somatic release can be a quantitatively significant component of serotonergic neurotransmission in the mammalian brain. J Neurosci Res 2009; 86:3469-80. [PMID: 18709651 DOI: 10.1002/jnr.21794] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent experiments on monoaminergic neurons have shown that neurotransmission can originate from somatic release. However, little is known about the quantity of monoamine available to be released through this extrasynaptic pathway or about the intracellular dynamics that mediate such release. Using three-photon microscopy, we directly imaged serotonin autofluorescence and investigated the total serotonin content, release competence, and release kinetics of somatic serotonergic vesicles in the dorsal raphe neurons of the rat. We found that the somata of primary cultured neurons contain a large number of serotonin-filled vesicles arranged in a perinuclear fashion. A similar distribution is also observed in fresh tissue slice preparations obtained from the rat dorsal raphe. We estimate that the soma of a cultured neuron on an average contains about 9 fmoles of serotonin in about 450 vesicles (or vesicle clusters) of < or =370 nm average diameter. A substantial fraction (>30%) of this serotonin is released with a time scale of several minutes by K(+)-induced depolarization or by para-chloroamphetamine treatment. The amount of releasable serotonin stored in the somatic vesicles is comparable to the total serotonin content of all the synaptic vesicles in a raphe neuron, indicating that somatic release can potentially play a major role in serotonergic neurotransmission in the mammalian brain.
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Affiliation(s)
- S K Kaushalya
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
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Descarries L, Bérubé-Carrière N, Riad M, Bo GD, Mendez JA, Trudeau LÉ. Glutamate in dopamine neurons: Synaptic versus diffuse transmission. ACTA ACUST UNITED AC 2008; 58:290-302. [DOI: 10.1016/j.brainresrev.2007.10.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 10/16/2007] [Accepted: 10/18/2007] [Indexed: 10/22/2022]
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36
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Sakamoto H, Matsuda KI, Zuloaga DG, Hongu H, Wada E, Wada K, Jordan CL, Breedlove SM, Kawata M. Sexually dimorphic gastrin releasing peptide system in the spinal cord controls male reproductive functions. Nat Neurosci 2008; 11:634-6. [PMID: 18488022 DOI: 10.1038/nn.2126] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Accepted: 04/21/2008] [Indexed: 01/01/2023]
Abstract
Neurons in the upper lumbar spinal cord project axons containing gastrin-releasing peptide (GRP) to innervate lower lumbar regions controlling erection and ejaculation. This system is vestigial in female rats and in males with genetic dysfunction of androgen receptors, but in male rats, pharmacological stimulation of spinal GRP receptors restores penile reflexes and ejaculation after castration. GRP offers new avenues for understanding potential therapeutic approaches to masculine reproductive dysfunction.
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Affiliation(s)
- Hirotaka Sakamoto
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602-8566, Japan.
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Chen W, Song B, Marvizón JCG. Inhibition of opioid release in the rat spinal cord by alpha2C adrenergic receptors. Neuropharmacology 2008; 54:944-53. [PMID: 18343461 DOI: 10.1016/j.neuropharm.2008.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 02/01/2008] [Accepted: 02/03/2008] [Indexed: 10/22/2022]
Abstract
Neurotransmitter receptors that control the release of opioid peptides in the spinal cord may play an important role in pain modulation. Norepinephrine, released by a descending pathway originating in the brainstem, is a powerful inducer of analgesia in the spinal cord. Adrenergic alpha2C receptors are present in opioid-containing terminals in the dorsal horn, where they could modulate opioid release. The goal of this study was to investigate this possibility. Opioid release was evoked from rat spinal cord slices by incubating them with the sodium channel opener veratridine in the presence of peptidase inhibitors (actinonin, captopril and thiorphan), and was measured in situ through the internalization of mu-opioid receptors in dorsal horn neurons. Veratridine produced internalization in 70% of these neurons. The alpha2 receptor agonists clonidine, guanfacine, medetomidine and UK-14304 inhibited the evoked mu-opioid receptor internalization with IC50s of 1.7 microM, 248 nM, 0.3 nM and 22 nM, respectively. However, inhibition by medetomidine was only partial, and inhibition by UK-14304 reversed itself at concentrations higher than 50 nM. None of these agonists inhibited mu-opioid receptor internalization produced by endomorphin-2, showing that they inhibited opioid release and not the internalization itself. The inhibitions produced by clonidine, guanfacine or UK-14304 were completely reversed by the selective alpha2C antagonist JP-1203. In contrast, inhibition by guanfacine was not prevented by the alpha2A antagonist BRL-44408. These results show that alpha2C receptors inhibit the release of opioids in the dorsal horn. This action may serve to shut down the opioid system when the adrenergic system is active.
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Affiliation(s)
- Wenling Chen
- Center for the Neurobiology of Stress and CURE: Digestive Diseases Research Center, Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Fuxe K, Dahlström A, Höistad M, Marcellino D, Jansson A, Rivera A, Diaz-Cabiale Z, Jacobsen K, Tinner-Staines B, Hagman B, Leo G, Staines W, Guidolin D, Kehr J, Genedani S, Belluardo N, Agnati LF. From the Golgi–Cajal mapping to the transmitter-based characterization of the neuronal networks leading to two modes of brain communication: Wiring and volume transmission. ACTA ACUST UNITED AC 2007; 55:17-54. [PMID: 17433836 DOI: 10.1016/j.brainresrev.2007.02.009] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 02/21/2007] [Accepted: 02/27/2007] [Indexed: 10/23/2022]
Abstract
After Golgi-Cajal mapped neural circuits, the discovery and mapping of the central monoamine neurons opened up for a new understanding of interneuronal communication by indicating that another form of communication exists. For instance, it was found that dopamine may be released as a prolactin inhibitory factor from the median eminence, indicating an alternative mode of dopamine communication in the brain. Subsequently, the analysis of the locus coeruleus noradrenaline neurons demonstrated a novel type of lower brainstem neuron that monosynaptically and globally innervated the entire CNS. Furthermore, the ascending raphe serotonin neuron systems were found to globally innervate the forebrain with few synapses, and where deficits in serotonergic function appeared to play a major role in depression. We propose that serotonin reuptake inhibitors may produce antidepressant effects through increasing serotonergic neurotrophism in serotonin nerve cells and their targets by transactivation of receptor tyrosine kinases (RTK), involving direct or indirect receptor/RTK interactions. Early chemical neuroanatomical work on the monoamine neurons, involving primitive nervous systems and analysis of peptide neurons, indicated the existence of alternative modes of communication apart from synaptic transmission. In 1986, Agnati and Fuxe introduced the theory of two main types of intercellular communication in the brain: wiring and volume transmission (WT and VT). Synchronization of phasic activity in the monoamine cell clusters through electrotonic coupling and synaptic transmission (WT) enables optimal VT of monoamines in the target regions. Experimental work suggests an integration of WT and VT signals via receptor-receptor interactions, and a new theory of receptor-connexin interactions in electrical and mixed synapses is introduced. Consequently, a new model of brain function must be built, in which communication includes both WT and VT and receptor-receptor interactions in the integration of signals. This will lead to the unified execution of information handling and trophism for optimal brain function and survival.
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Affiliation(s)
- Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden.
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Abstract
Vascular cognitive impairment/vascular dementia have been the subject of a large
number of studies, due to their high prevalence and broad preventive and
compensatory therapeutic potential. The knowledge of the cerebral anatomy
correlated to the vascular territories of irrigation enables understanding of
clinical manifestations, as well as classification into the several types of
syndromic presentations. The central cholinergic system exercises important
neuromodulatory functions on cerebral circuits related to cognitive and
behavioral integration, as well as on vasomotor control related to cerebral
blood flow adjustments. The acquisition of data on the anatomy of the
cholinergic pathways, including the localization of the nuclei of the basal
prosencephalon and the routes of their projections, established an important
milestone. The knowledge of the vascular distribution and of the trajectories of
the cholinergic pathways allows identification of the strategic points where a
vascular lesion can cause interruption. The ensuing denervation leads to
cholinergic hypofunction in the involved territories. This information proves
important to better evaluate the sites of vascular lesions, emphasizing their
strategic localizations in relation to the cholinergic pathways, and offering
more robust foundations for treatment aiming at enhancing cholinergic
activity.
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Pertovaara A. Noradrenergic pain modulation. Prog Neurobiol 2006; 80:53-83. [PMID: 17030082 DOI: 10.1016/j.pneurobio.2006.08.001] [Citation(s) in RCA: 394] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 08/25/2006] [Accepted: 08/30/2006] [Indexed: 11/18/2022]
Abstract
Norepinephrine is involved in intrinsic control of pain. Main sources of norepinephrine are sympathetic nerves peripherally and noradrenergic brainstem nuclei A1-A7 centrally. Peripheral norepinephrine has little influence on pain in healthy tissues, whereas in injured tissues it has variable effects, including aggravation of pain. Its peripheral pronociceptive effect has been associated with injury-induced expression of novel noradrenergic receptors, sprouting of sympathetic nerve fibers, and pronociceptive changes in the ionic channel properties of primary afferent nociceptors, while an interaction with the immune system may contribute in part to peripheral antinociception induced by norepinephrine. In the spinal cord, norepinephrine released from descending pathways suppresses pain by inhibitory action on alpha-2A-adrenoceptors on central terminals of primary afferent nociceptors (presynaptic inhibition), by direct alpha-2-adrenergic action on pain-relay neurons (postsynaptic inhibition), and by alpha-1-adrenoceptor-mediated activation of inhibitory interneurons. Additionally, alpha-2C-adrenoceptors on axon terminals of excitatory interneurons of the spinal dorsal horn possibly contribute to spinal control of pain. At supraspinal levels, the pain modulatory effect by norepinephrine and noradrenergic receptors has varied depending on many factors such as the supraspinal site, the type of the adrenoceptor, the duration of the pain and pathophysiological condition. While in baseline conditions the noradrenergic system may have little effect, sustained pain induces noradrenergic feedback inhibition of pain. Noradrenergic systems may also contribute to top-down control of pain, such as induced by a change in the behavioral state. Following injury or inflammation, the central as well as peripheral noradrenergic system is subject to various plastic changes that influence its antinociceptive efficacy.
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Affiliation(s)
- Antti Pertovaara
- Biomedicum Helsinki, Institute of Biomedicine/Physiology, PO Box 63, University of Helsinki, FIN-00014 Helsinki, Finland.
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Mazloom M, Smith Y. Synaptic microcircuitry of tyrosine hydroxylase-containing neurons and terminals in the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated monkeys. J Comp Neurol 2006; 495:453-69. [PMID: 16485290 PMCID: PMC2597082 DOI: 10.1002/cne.20894] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A population of tyrosine hydroxylase (TH)-containing neurons that is up-regulated after lesion of the nigrostriatal dopaminergic pathway has been described in the primate striatum. The goal of this study was to examine the morphology, synaptology, and chemical phenotype of these neurons and TH-immunoreactive (-ir) terminals in the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated rhesus monkeys. TH-ir perikarya were small (10-12 microm), displayed nuclear invaginations, and received very few synaptic inputs. On the other hand, TH-containing dendrites were typically large in diameter (>1.0 microm) and received scarce synaptic innervation from putative excitatory and inhibitory terminals forming asymmetric and symmetric synapses, respectively. More than 70% of TH-positive intrastriatal cell bodies were found in the caudate nucleus and the precommissural putamen, considered as the associative functional territories of the primate striatum. Under 10% of these cells displayed calretinin immunoreactivity. TH-ir terminals rarely formed clear synaptic contacts, except for a few that established asymmetric axodendritic synapses. Almost two-thirds of TH-containing boutons displayed gamma-aminobutyric acid (GABA) immunoreactivity in the striatum of parkinsonian monkeys, whereas under 5% did so in the normal striatum. These findings provide strong support for the existence of a population of putative catecholaminergic interneurons in the associative territory of the striatum in parkinsonian monkeys. Their sparse synaptic innervation raises interesting issues regarding synaptic and nonsynaptic mechanisms involved in the regulation and integration of these neurons in the striatal microcircuitry. Finally, the coexpression of GABA in TH-positive terminals in the striatum of dopamine-depleted monkeys suggests dramatic neurochemical changes in the catecholaminergic modulation of striatal activity in Parkinson's disease.
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Affiliation(s)
- Maney Mazloom
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30322, USA
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Okere CO, Waterhouse BD. Activity-dependent heterogeneous populations of nitric oxide synthase neurons in the rat dorsal raphe nucleus. Brain Res 2006; 1086:117-32. [PMID: 16616732 DOI: 10.1016/j.brainres.2006.02.107] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 02/17/2006] [Accepted: 02/20/2006] [Indexed: 11/18/2022]
Abstract
The brainstem dorsal raphe nucleus (DRN) contains an abundant distribution of nitric oxide (NO) synthase (NOS)-containing neuronal profiles in two distinct populations: faint- and intense-immunoreactive cells in midline (ventromedial and dorsomedial) and lateral wing subregions, respectively. This study tested the hypothesis that different functional dynamics underlie the topography of NOS-containing cells in the DRN rostrocaudal and mediolateral neuraxis by using a capsaicin challenge paradigm (50 mg/kg, subcutaneous). Compared with vehicle, capsaicin significantly and preferentially increased nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d, an index of constitutive NOS) reactivity in the rostral midline and caudal lateral wing subregions. Furthermore, capsaicin activated more Fos-positive cells than vehicle within all subregions of the DRN but with a caudal versus rostral predominance in activation pattern. In addition, a high proportion of capsaicin-induced Fos cells in the midline but almost none in lateral wing stained for NADPH-d. These observations suggest the existence of two functionally distinct populations of NOS neurons in the DRN. Furthermore, capsaicin increased galanin immunoreactivity with predominant staining in cell soma and fiber processes in midline and lateral wing subregions of the nucleus, respectively. The total capsaicin-induced galanin immunoreactivity was higher in rostral versus caudal DRN, and a high proportion of galanin-positive cells in the midline also contained NADPH-d and neuronal NOS, thus suggesting a potential NO-galanin interaction in these neurons. The differential pattern of Fos/NADPH-d colocalization across the nucleus suggests that midline and lateral wing NOS neurons of the DRN express their neuromodulatory actions on discrete efferent targets via different intracellular mechanisms.
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Affiliation(s)
- Chuma O Okere
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 W Queen Lane, Philadelphia, PA 19129, USA.
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43
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Guigoni C, Dovero S, Aubert I, Li Q, Bioulac BH, Bloch B, Gurevich EV, Gross CE, Bezard E. Levodopa-induced dyskinesia in MPTP-treated macaques is not dependent on the extent and pattern of nigrostrial lesioning. Eur J Neurosci 2005; 22:283-7. [PMID: 16029219 DOI: 10.1111/j.1460-9568.2005.04196.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The extent of nigrostriatal denervation is presumed to play a role in the genesis of levodopa-induced dyskinesia. Yet some parkinsonian patients who have been treated over a long period do not develop dyskinesia, raising the possibility that the pattern of denervation is as important as the extent of lesioning as a risk factor. Here we study the extent and pattern of nigrostriatal denervation in a homogeneous population of parkinsonian macaque monkeys chronically treated with levodopa. Based on the characteristics of the lesioning, non-dyskinetic animals could not be differentiated from those with dyskinesia. Indeed, the number of tyrosine-hydroxylase (TH)-immunopositive neurons in the substantia nigra pars compacta, striatal dopamine transporter (DAT) binding and TH immunostaining, as well as the overall TH striatal content measured by Western blotting were identical. Moreover, the patterns of lesioning assessed by a detailed analysis of the TH- and DAT-immunopositive striatal fibers were comparable in all functional quadrants and at all rostro-caudal levels considered. These data indicate that neither the extent nor the pattern of nigrostriatal lesioning are sufficient to explain the occurrence of levodopa-induced dyskinesia.
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Affiliation(s)
- Céline Guigoni
- Laboratoire de Physiologie et Physiopathologie de la Signalization Cellulaire, CNRS UMR 5543, Universite victor Segalen-Bordeaux, 33076 Bordeaux Cedex, France
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44
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Song Y, Zhang Y, Shen T, Bajaj CL, McCammon JA, Baker NA. Finite element solution of the steady-state Smoluchowski equation for rate constant calculations. Biophys J 2004; 86:2017-29. [PMID: 15041644 PMCID: PMC1304055 DOI: 10.1016/s0006-3495(04)74263-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
This article describes the development and implementation of algorithms to study diffusion in biomolecular systems using continuum mechanics equations. Specifically, finite element methods have been developed to solve the steady-state Smoluchowski equation to calculate ligand binding rate constants for large biomolecules. The resulting software has been validated and applied to mouse acetylcholinesterase. Rates for inhibitor binding to mAChE were calculated at various ionic strengths with several different reaction criteria. The calculated rates were compared with experimental data and show very good agreement when the correct reaction criterion is used. Additionally, these finite element methods require significantly less computational resources than existing particle-based Brownian dynamics methods.
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Affiliation(s)
- Yuhua Song
- Department of Biochemistry and Molecular Biophysics, Center for Computational Biology, Washington University in St. Louis, St. Louis, Missouri 63110, USA
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45
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Pioli E, Sohr R, Meissner W, Barthe N, Gross CE, Bezard E, Bioulac BH. Partial bilateral mesencephalic lesions affect D1 but not D2 binding in both the striatum and cortex. Neurochem Int 2004; 45:995-1004. [PMID: 15337298 DOI: 10.1016/j.neuint.2004.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Revised: 06/01/2004] [Accepted: 06/01/2004] [Indexed: 11/26/2022]
Abstract
The substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA) are the two major mesencephalic dopaminergic systems. Mesencephalic dopamine denervation is followed by long-term modifications in striatum and cortex that preserve dopamine functions. Here, we have studied the impact of isolated bilateral 6-hydroxydopamine lesioning of the SNc or the VTA on D(1) and D(2) dopamine receptor binding in striatal and cortical areas of rat. Neither SNc nor VTA bilateral partial lesioning changed D(2) binding at the striatal or cortical level. Intriguingly, only VTA lesioning increased D(1) binding in the cortex, whereas both bilateral partial lesioning of the SNc or the VTA increased striatal D(1) binding. This suggests that increased cortical D(1) binding could be an indicator of VTA lesioning. Further behavioural experiments may explain the pathophysiological meaning of increased cortical D(1) binding, and determine whether this observation is involved in compensatory mechanisms.
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Affiliation(s)
- Elsa Pioli
- Basal Gang, Laboratoire de Physiologie et Physiopathologie de la Signalisation Cellulaire, CNRS UMR 5543, Université Victor Segalen, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France.
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46
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Faingold CL. Emergent properties of CNS neuronal networks as targets for pharmacology: application to anticonvulsant drug action. Prog Neurobiol 2004; 72:55-85. [PMID: 15019176 DOI: 10.1016/j.pneurobio.2003.11.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2003] [Accepted: 11/19/2003] [Indexed: 01/13/2023]
Abstract
CNS drugs may act by modifying the emergent properties of complex CNS neuronal networks. Emergent properties are network characteristics that are not predictably based on properties of individual member neurons. Neuronal membership within networks is controlled by several mechanisms, including burst firing, gap junctions, endogenous and exogenous neuroactive substances, extracellular ions, temperature, interneuron activity, astrocytic integration and external stimuli. The effects of many CNS drugs in vivo may critically involve actions on specific brain loci, but this selectivity may be absent when the same neurons are isolated from the network in vitro where emergent properties are lost. Audiogenic seizures (AGS) qualify as an emergent CNS property, since in AGS the acoustic stimulus evokes a non-linear output (motor convulsion), but the identical stimulus evokes minimal behavioral changes normally. The hierarchical neuronal network, subserving AGS in rodents is initiated in inferior colliculus (IC) and progresses to deep layers of superior colliculus (DLSC), pontine reticular formation (PRF) and periaqueductal gray (PAG) in genetic and ethanol withdrawal-induced AGS. In blocking AGS, certain anticonvulsants reduce IC neuronal firing, while other agents act primarily on neurons in other AGS network sites. However, the NMDA receptor channel blocker, MK-801, does not depress neuronal firing in any network site despite potently blocking AGS. Recent findings indicate that MK-801 actually enhances firing in substantia nigra reticulata (SNR) neurons in vivo but not in vitro. Thus, the MK-801-induced firing increases in SNR neurons observed in vivo may involve an indirect effect via disinhibition, involving an action on the emergent properties of this seizure network.
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Affiliation(s)
- Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, USA.
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Lever IJ, Grant AD, Pezet S, Gerard NP, Brain SD, Malcangio M. Basal and activity-induced release of substance P from primary afferent fibres in NK1 receptor knockout mice: evidence for negative feedback. Neuropharmacology 2003; 45:1101-10. [PMID: 14614953 DOI: 10.1016/s0028-3908(03)00298-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The concept that NK1 receptors are located pre-junctionally on substance P (SP)-containing nerves, acting as autoreceptors to inhibit SP release, has been suggested, but remains a controversial issue. To further investigate the existence of this receptor on central and peripheral terminals of primary afferent fibres, NK1 receptor knockout mice and an NK1 receptor antagonist were used in nerve-attached tissue preparations. These were the isolated dorsal horn of the spinal cord with dorsal roots attached, and the hairy skin of the hind paw with attached saphenous nerve. The results reveal that in the dorsal horn preparation, basal release of SP is significantly higher in NK1(-/-) mice than NK1(+/+) mice (P<0.05, n=7 mice/strain). However, a difference in SP release evoked in the dorsal horn by electrical stimulation of the dorsal roots or capsaicin application was not observed. In contrast, antidromic electrical stimulation of the saphenous nerve caused a substantially greater release of SP in the skin of NK1(-/-) mice than in NK1(+/+) mice (P<0.05, n=5 to 6 mice/strain). These results provide evidence for the existence of NK1 autoreceptors on sensory nerves in skin, which may be relevant to the modulation of their peripheral pathophysiological effector functions.
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Affiliation(s)
- Isobel J Lever
- Centre for Neuroscience, Hodgkin Building, Guy's Campus, King's College, London SE1 1UL, UK
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Di Angelantonio S, Giniatullin R, Costa V, Sokolova E, Nistri A. Modulation of neuronal nicotinic receptor function by the neuropeptides CGRP and substance P on autonomic nerve cells. Br J Pharmacol 2003; 139:1061-73. [PMID: 12871824 PMCID: PMC1573932 DOI: 10.1038/sj.bjp.0705337] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2003] [Accepted: 04/29/2003] [Indexed: 11/08/2022] Open
Abstract
1. One classical example of how neuropeptides can affect the function of ligand-gated receptors is the modulation of neuronal nicotinic receptors (nAChRs) by substance P. The present review updates current understanding of this action by substance P and compares it with other neuropeptides more recently found to modulate nAChRs in the autonomic nervous system. 2. Calcitonin gene-related peptide (CGRP) and its N-terminal fragments have been shown to exert complex inhibitory as well facilitatory actions on nAChRs. Fragments such as CGRP(1-4), CGRP(1-5) and CGRP(1-6) rapidly and reversibly enhance agonist sensitivity of nAChRs without directly activating those receptors. Longer fragments or the full-length peptide potently inhibit responses mediated by nAChRs via an apparently competitive-type antagonism. This phenomenon differs from the substance P-induced block, which is agonist use-dependent and preferential towards large nicotinic responses. 3. It is argued that the full-length peptides CGRP and substance P might play distinct roles in the activity-dependent modulation of cholinergic neurotransmission, by inhibiting background noise in the case of CGRP or by reducing excessive excitation in the case of substance P. Hence, multiple neuropeptide mechanisms may represent a wide array of fine-tuning processes to regulate nicotinic synaptic transmission. 4. The availability of novel CGRP derivatives with a strong enhancing action on nAChRs may offer new leads for the drug design targeted for potentiation of nAChRs in the autonomic nervous system as well as in the brain, a subject of interest to counteract the deficit of the nAChR function associated with neurodegenerative diseases like Alzheimer's and Parkinson's diseases.
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Affiliation(s)
- Silvia Di Angelantonio
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
- IRCCS St Lucia, Via Ardeatina 306, 00178 Rome, Italy
| | - Rashid Giniatullin
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Valeria Costa
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Elena Sokolova
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Andrea Nistri
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
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Del Arco A, Segovia G, Fuxe K, Mora F. Changes in dialysate concentrations of glutamate and GABA in the brain: an index of volume transmission mediated actions? J Neurochem 2003; 85:23-33. [PMID: 12641724 DOI: 10.1046/j.1471-4159.2003.01692.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Brain microdialysis has become a frequently used method to study the extracellular concentrations of neurotransmitters in specific areas of the brain. For years, and this is still the case today, dialysate concentrations and hence extracellular concentrations of neurotransmitters have been interpreted as a direct index of the neuronal release of these specific neurotransmitter systems. Although this seems to be the case for neurotransmitters such as dopamine, serotonin and acetylcholine, the extracellular concentrations of glutamate and GABA do not provide a reliable index of their synaptic exocytotic release. However, many microdialysis studies show changes in extracellular concentrations of glutamate and GABA under specific pharmacological and behavioural stimuli that could be interpreted as a consequence of the activation of specific neurochemical circuits. Despite this, we still do not know the origin and physiological significance of these changes of glutamate and GABA in the extracellular space. Here we propose that the changes in dialysate concentrations of these two neurotransmitters found under specific treatments could be an expression of the activity of the neurone-astrocyte unit in specific circuits of the brain. It is further proposed that dialysate changes of glutamate and GABA could be used as an index of volume transmission mediated actions of these two neurotransmitters in the brain. This hypothesis is based firstly on the assumption that the activity of neurones is functionally linked to the activity of astrocytes, which can release glutamate and GABA to the extracellular space; secondly, on the existence of extrasynaptic glutamate and GABA receptors with functional properties different from those of GABA receptors located at the synapse; and thirdly, on the experimental evidence reporting specific electrophysiological and neurochemical effects of glutamate and GABA when their levels are increased in the extracellular space. According to this concept, glutamate and GABA, once released into the extracellular compartment, could diffuse and have long-lasting effects modulating glutamatergic and/or GABAergic neurone-astrocytic networks and their interactions with other neurotransmitter neurone networks in the same areas of the brain.
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Affiliation(s)
- A Del Arco
- Department of Physiology, Faculty of Medicine, University Complutense, Madrid, Spain
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50
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Orekhova IV, Alexeeva V, Church PJ, Weiss KR, Brezina V. Multiple presynaptic and postsynaptic sites of inhibitory modulation by myomodulin at ARC neuromuscular junctions of Aplysia. J Neurophysiol 2003; 89:1488-502. [PMID: 12626624 DOI: 10.1152/jn.00140.2002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The functional activity of even simple cellular ensembles is often controlled by surprisingly complex networks of neuromodulators. One such network has been extensively studied in the accessory radula closer (ARC) neuromuscular system of Aplysia. The ARC muscle is innervated by two motor neurons, B15 and B16, which release modulatory peptide cotransmitters to shape ACh-mediated contractions of the muscle. Previous analysis has shown that key to the combinatorial ability of B15 and B16 to control multiple parameters of the contraction is an asymmetry in their peptide modulatory actions. B16, but not B15, releases myomodulin, which, among other actions, inhibits the contraction. Work in single ARC muscle fibers has identified a distinctive myomodulin-activated K current as a candidate postsynaptic mechanism of the inhibition. However, definitive evidence for this mechanism has been lacking. Here, working with the single fibers and then motor neuron-elicited excitatory junction potentials (EJPs) and contractions of the intact ARC muscle, we have confirmed two central predictions of the K-current hypothesis: the myomodulin inhibition of contraction is associated with a correspondingly large inhibition of the underlying depolarization, and the inhibition of both contraction and depolarization is blocked by 4-aminopyridine (4-AP), a potent and selective blocker of the myomodulin-activated K current. However, in the intact muscle, the experiments revealed a second, 4-AP-resistant component of myomodulin inhibition of both B15- and B16-elicited EJPs. This component resembles, and mutually occludes with, inhibition of the EJPs by another peptide modulator released from both B15 and B16, buccalin, which acts by a presynaptic mechanism, inhibition of ACh release from the motor neuron terminals. Direct measurements of peptide release showed that myomodulin also inhibits buccalin release from B15 terminals. At the level of contractions, nevertheless, the postsynaptic K-current mechanism is responsible for much of the myomodulin inhibition of peak contraction amplitude. The presynaptic mechanism, which is most evident during the initial build-up of the EJP waveform, underlies instead an increase of contraction latency.
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Affiliation(s)
- Irina V Orekhova
- Department of Physiology and Biophysics, and Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York City, New York 10029, USA
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