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Borroto-Escuela DO, Gonzalez-Cristo E, Ochoa-Torres V, Serra-Rojas EM, Ambrogini P, Arroyo-García LE, Fuxe K. Understanding electrical and chemical transmission in the brain. Front Cell Neurosci 2024; 18:1398862. [PMID: 38988663 PMCID: PMC11233782 DOI: 10.3389/fncel.2024.1398862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024] Open
Abstract
The histochemical Falck-Hillarp method for the localization of dopamine (DA), noradrenaline (NA) and serotonin in the central nervous system (CNS) of rodents was introduced in the 1960s. It supported the existence of chemical neurotransmission in the CNS. The monoamine neurons in the lower brain stem formed monosynaptic ascending systems to the telencephalon and diencephalon and monoamine descending systems to the entire spinal cord. The monoamines were early on suggested to operate via synaptic chemical transmission in the CNS. This chemical transmission reduced the impact of electrical transmission. In 1969 and the 1970s indications were obtained that important modes of chemical monoamine communication in the CNS also took place through the extra-synaptic fluid, the extracellular fluid, and long-distance communication in the cerebrospinal fluid involving diffusion and flow of transmitters like DA, NA and serotonin. In 1986, this type of transmission was named volume transmission (VT) by Agnati and Fuxe and their colleagues, also characterized by transmitter varicosity and receptor mismatches. The short and long-distance VT pathways were characterized by volume fraction, tortuosity and clearance. Electrical transmission also exists in the mammalian CNS, but chemical transmission is in dominance. One electrical mode is represented by electrical synapses formed by gap junctions which represent low resistant passages between nerve cells. It allows for a more rapid passage of action potentials between nerve cells compared to chemical transmission. The second mode is based on the ability of synaptic currents to generate electrical fields to modulate chemical transmission. One aim is to understand how chemical transmission can be integrated with electrical transmission and how putative (aquaporin water channel, dopamine D2R and adenosine A2AR) complexes in astrocytes can significancy participate in the clearance of waste products from the glymphatic system. VT may also help accomplish the operation of the acupuncture meridians essential for Chinese medicine in view of the indicated existence of extracellular VT pathways.
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Affiliation(s)
- Dasiel O. Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Receptomics and Brain Disorders Lab, Department of Human Physiology Physical Education and Sport, Faculty of Medicine, University of Malaga, Málaga, Spain
| | - Emmanuell Gonzalez-Cristo
- Receptomics and Brain Disorders Lab, Department of Human Physiology Physical Education and Sport, Faculty of Medicine, University of Malaga, Málaga, Spain
| | - Verty Ochoa-Torres
- Receptomics and Brain Disorders Lab, Department of Human Physiology Physical Education and Sport, Faculty of Medicine, University of Malaga, Málaga, Spain
- Faculty of Engineering and Biotechnology, University OTR and the Regional Cooperative for Comprehensive Medical Assistance (CRAMI), Montevideo, Uruguay
| | - Emilio M. Serra-Rojas
- Receptomics and Brain Disorders Lab, Department of Human Physiology Physical Education and Sport, Faculty of Medicine, University of Malaga, Málaga, Spain
- Cardiology Service, Lozano Blesa University Clinical Hospital, Zaragoza, Spain
| | - Patrizia Ambrogini
- Department of Biomolecular Sciences, Università di Urbino Carlo Bo, Urbino, Italy
| | - Luis E. Arroyo-García
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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2
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Özçete ÖD, Banerjee A, Kaeser PS. Mechanisms of neuromodulatory volume transmission. Mol Psychiatry 2024:10.1038/s41380-024-02608-3. [PMID: 38789677 DOI: 10.1038/s41380-024-02608-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/07/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
A wealth of neuromodulatory transmitters regulate synaptic circuits in the brain. Their mode of signaling, often called volume transmission, differs from classical synaptic transmission in important ways. In synaptic transmission, vesicles rapidly fuse in response to action potentials and release their transmitter content. The transmitters are then sensed by nearby receptors on select target cells with minimal delay. Signal transmission is restricted to synaptic contacts and typically occurs within ~1 ms. Volume transmission doesn't rely on synaptic contact sites and is the main mode of monoamines and neuropeptides, important neuromodulators in the brain. It is less precise than synaptic transmission, and the underlying molecular mechanisms and spatiotemporal scales are often not well understood. Here, we review literature on mechanisms of volume transmission and raise scientific questions that should be addressed in the years ahead. We define five domains by which volume transmission systems can differ from synaptic transmission and from one another. These domains are (1) innervation patterns and firing properties, (2) transmitter synthesis and loading into different types of vesicles, (3) architecture and distribution of release sites, (4) transmitter diffusion, degradation, and reuptake, and (5) receptor types and their positioning on target cells. We discuss these five domains for dopamine, a well-studied monoamine, and then compare the literature on dopamine with that on norepinephrine and serotonin. We include assessments of neuropeptide signaling and of central acetylcholine transmission. Through this review, we provide a molecular and cellular framework for volume transmission. This mechanistic knowledge is essential to define how neuromodulatory systems control behavior in health and disease and to understand how they are modulated by medical treatments and by drugs of abuse.
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Affiliation(s)
- Özge D Özçete
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Aditi Banerjee
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
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3
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Gianni G, Pasqualetti M. Wiring and Volume Transmission: An Overview of the Dual Modality for Serotonin Neurotransmission. ACS Chem Neurosci 2023; 14:4093-4104. [PMID: 37966717 DOI: 10.1021/acschemneuro.3c00648] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023] Open
Abstract
Serotonin is a neurotransmitter involved in the modulation of a multitude of physiological and behavioral processes. In spite of the relatively reduced number of serotonin-producing neurons present in the mammalian CNS, a complex long-range projection system provides profuse innervation to the whole brain. Heterogeneity of serotonin receptors, grouped in seven families, and their spatiotemporal expression pattern account for its widespread impact. Although neuronal communication occurs primarily at tiny gaps called synapses, wiring transmission, another mechanism based on extrasynaptic diffusion of neuroactive molecules and referred to as volume transmission, has been described. While wiring transmission is a rapid and specific one-to-one modality of communication, volume transmission is a broader and slower mode in which a single element can simultaneously act on several different targets in a one-to-many mode. Some experimental evidence regarding ultrastructural features, extrasynaptic localization of receptors and transporters, and serotonin-glia interactions collected over the past four decades supports the existence of a serotonergic system of a dual modality of neurotransmission, in which wiring and volume transmission coexist. To date, in spite of the radical difference in the two modalities, limited information is available on the way they are coordinated to mediate the specific activities in which serotonin participates. Understanding how wiring and volume transmission modalities contribute to serotonergic neurotransmission is of utmost relevance for the comprehension of serotonin functions in both physiological and pathological conditions.
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Affiliation(s)
- Giulia Gianni
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56127 Pisa, Italy
| | - Massimo Pasqualetti
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56127 Pisa, Italy
- Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy
- Centro per l'Integrazione della Strumentazione Scientifica dell'Università di Pisa (CISUP), 56126 Pisa, Italy
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4
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Peltekian L, Gasparini S, Fazan FS, Karthik S, Iverson G, Resch JM, Geerling JC. Sodium appetite and thirst do not require angiotensinogen production in astrocytes or hepatocytes. J Physiol 2023; 601:3499-3532. [PMID: 37291801 DOI: 10.1113/jp283169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/02/2023] [Indexed: 06/10/2023] Open
Abstract
In addition to its renal and cardiovascular functions, angiotensin signalling is thought to be responsible for the increases in salt and water intake caused by hypovolaemia. However, it remains unclear whether these behaviours require angiotensin production in the brain or liver. Here, we use in situ hybridization to identify tissue-specific expression of the genes required for producing angiotensin peptides, and then use conditional genetic deletion of the angiotensinogen gene (Agt) to test whether production in the brain or liver is necessary for sodium appetite and thirst. In the mouse brain, we identified expression of Agt (the precursor for all angiotensin peptides) in a large subset of astrocytes. We also identified Ren1 and Ace (encoding enzymes required to produce angiotensin II) expression in the choroid plexus, and Ren1 expression in neurons within the nucleus ambiguus compact formation. In the liver, we confirmed that Agt is widely expressed in hepatocytes. We next tested whether thirst and sodium appetite require angiotensinogen production in astrocytes or hepatocytes. Despite virtually eliminating expression in the brain, deleting astrocytic Agt did not reduce thirst or sodium appetite. Despite markedly reducing angiotensinogen in the blood, eliminating Agt from hepatocytes did not reduce thirst or sodium appetite, and in fact, these mice consumed the largest amounts of salt and water after sodium deprivation. Deleting Agt from both astrocytes and hepatocytes also did not prevent thirst or sodium appetite. Our findings suggest that angiotensin signalling is not required for sodium appetite or thirst and highlight the need to identify alternative signalling mechanisms. KEY POINTS: Angiotensin signalling is thought to be responsible for the increased thirst and sodium appetite caused by hypovolaemia, producing elevated water and sodium intake. Specific cells in separate brain regions express the three genes needed to produce angiotensin peptides, but brain-specific deletion of the angiotensinogen gene (Agt), which encodes the lone precursor for all angiotensin peptides, did not reduce thirst or sodium appetite. Double-deletion of Agt from brain and liver also did not reduce thirst or sodium appetite. Liver-specific deletion of Agt reduced circulating angiotensinogen levels without reducing thirst or sodium appetite. Instead, these angiotensin-deficient mice exhibited an enhanced sodium appetite. Because the physiological mechanisms controlling thirst and sodium appetite continued functioning without angiotensin production in the brain and liver, understanding these mechanisms requires a renewed search for the hypovolaemic signals necessary for activating each behaviour.
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Affiliation(s)
- Lila Peltekian
- Department of Neurology, University of Iowa, Iowa City, IA, USA
| | | | | | | | | | - Jon M Resch
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Joel C Geerling
- Department of Neurology, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
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5
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Singh I, Wang L, Xia B, Liu J, Tahiri A, El Ouaamari A, Wheeler MB, Pang ZP. Activation of arcuate nucleus glucagon-like peptide-1 receptor-expressing neurons suppresses food intake. Cell Biosci 2022; 12:178. [PMID: 36309763 PMCID: PMC9618215 DOI: 10.1186/s13578-022-00914-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/11/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Central nervous system (CNS) control of metabolism plays a pivotal role in maintaining energy balance. In the brain, Glucagon-like peptide 1 (GLP-1), encoded by the proglucagon 'Gcg' gene, produced in a distinct population of neurons in the nucleus tractus solitarius (NTS), has been shown to regulate feeding behavior leading to the suppression of appetite. However, neuronal networks that mediate endogenous GLP-1 action in the CNS on feeding and energy balance are not well understood. RESULTS We analyzed the distribution of GLP-1R-expressing neurons and axonal projections of NTS GLP-1-producing neurons in the mouse brain. GLP-1R neurons were found to be broadly distributed in the brain and specific forebrain regions, particularly the hypothalamus, including the arcuate nucleus of the hypothalamus (ARC), a brain region known to regulate energy homeostasis and feeding behavior, that receives dense NTSGcg neuronal projections. The impact of GLP-1 signaling in the ARC GLP-1R-expressing neurons and the impact of activation of ARC GLP-1R on food intake was examined. Application of GLP-1R specific agonist Exendin-4 (Exn-4) enhanced a proportion of the ARC GLP-1R-expressing neurons and pro-opiomelanocortin (POMC) neuronal action potential firing rates. Chemogenetic activation of the ARC GLP-1R neurons by using Cre-dependent hM3Dq AAV in the GLP-1R-ires-Cre mice, established that acute activation of the ARC GLP-1R neurons significantly suppressed food intake but did not have a strong impact on glucose homeostasis. CONCLUSIONS These results highlight the importance of central GLP-1 signaling in the ARC that express GLP-1R that upon activation, regulate feeding behavior.
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Affiliation(s)
- Ishnoor Singh
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.17063.330000 0001 2157 2938Department of Physiology, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada
| | - Le Wang
- The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
| | - Baijuan Xia
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.413458.f0000 0000 9330 9891School of Basic Medical Sciences, Guizhou Medical University, Guiyang, Guizhou, 550025 China
| | - Ji Liu
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.59053.3a0000000121679639National Engineering Laboratory for Brain-Inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Hefei, 230026 Anhui China
| | - Azeddine Tahiri
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
| | - Abdelfattah El Ouaamari
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.430387.b0000 0004 1936 8796Department of Medicine, Division of Endocrinology, Metabolism and Nutrition, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
| | - Michael B. Wheeler
- grid.17063.330000 0001 2157 2938Department of Physiology, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada ,Metabolism Research Group, Division of Advanced Diagnostics, Toronto, ON Canada
| | - Zhiping P. Pang
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.430387.b0000 0004 1936 8796Department of Neuroscience and Cell Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.430387.b0000 0004 1936 8796Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
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6
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Casello SM, Flores RJ, Yarur HE, Wang H, Awanyai M, Arenivar MA, Jaime-Lara RB, Bravo-Rivera H, Tejeda HA. Neuropeptide System Regulation of Prefrontal Cortex Circuitry: Implications for Neuropsychiatric Disorders. Front Neural Circuits 2022; 16:796443. [PMID: 35800635 PMCID: PMC9255232 DOI: 10.3389/fncir.2022.796443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 04/27/2022] [Indexed: 01/08/2023] Open
Abstract
Neuropeptides, a diverse class of signaling molecules in the nervous system, modulate various biological effects including membrane excitability, synaptic transmission and synaptogenesis, gene expression, and glial cell architecture and function. To date, most of what is known about neuropeptide action is limited to subcortical brain structures and tissue outside of the central nervous system. Thus, there is a knowledge gap in our understanding of neuropeptide function within cortical circuits. In this review, we provide a comprehensive overview of various families of neuropeptides and their cognate receptors that are expressed in the prefrontal cortex (PFC). Specifically, we highlight dynorphin, enkephalin, corticotropin-releasing factor, cholecystokinin, somatostatin, neuropeptide Y, and vasoactive intestinal peptide. Further, we review the implication of neuropeptide signaling in prefrontal cortical circuit function and use as potential therapeutic targets. Together, this review summarizes established knowledge and highlights unknowns of neuropeptide modulation of neural function underlying various biological effects while offering insights for future research. An increased emphasis in this area of study is necessary to elucidate basic principles of the diverse signaling molecules used in cortical circuits beyond fast excitatory and inhibitory transmitters as well as consider components of neuropeptide action in the PFC as a potential therapeutic target for neurological disorders. Therefore, this review not only sheds light on the importance of cortical neuropeptide studies, but also provides a comprehensive overview of neuropeptide action in the PFC to serve as a roadmap for future studies in this field.
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Affiliation(s)
- Sanne M. Casello
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Rodolfo J. Flores
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Hector E. Yarur
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Huikun Wang
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Monique Awanyai
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Miguel A. Arenivar
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Rosario B. Jaime-Lara
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Hector Bravo-Rivera
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Hugo A. Tejeda
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Hugo A. Tejeda,
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7
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Pagella S, Deussing JM, Kopp-Scheinpflug C. Expression Patterns of the Neuropeptide Urocortin 3 and Its Receptor CRFR2 in the Mouse Central Auditory System. Front Neural Circuits 2021; 15:747472. [PMID: 34867212 PMCID: PMC8633543 DOI: 10.3389/fncir.2021.747472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022] Open
Abstract
Sensory systems have to be malleable to context-dependent modulations occurring over different time scales, in order to serve their evolutionary function of informing about the external world while also eliciting survival-promoting behaviors. Stress is a major context-dependent signal that can have fast and delayed effects on sensory systems, especially on the auditory system. Urocortin 3 (UCN3) is a member of the corticotropin-releasing factor family. As a neuropeptide, UCN3 regulates synaptic activity much faster than the classic steroid hormones of the hypothalamic-pituitary-adrenal axis. Moreover, due to the lack of synaptic re-uptake mechanisms, UCN3 can have more long-lasting and far-reaching effects. To date, a modest number of studies have reported the presence of UCN3 or its receptor CRFR2 in the auditory system, particularly in the cochlea and the superior olivary complex, and have highlighted the importance of this stress neuropeptide for protecting auditory function. However, a comprehensive map of all neurons synthesizing UCN3 or CRFR2 within the auditory pathway is lacking. Here, we utilize two reporter mouse lines to elucidate the expression patterns of UCN3 and CRFR2 in the auditory system. Additional immunolabelling enables further characterization of the neurons that synthesize UCN3 or CRFR2. Surprisingly, our results indicate that within the auditory system, UCN3 is expressed predominantly in principal cells, whereas CRFR2 expression is strongest in non-principal, presumably multisensory, cell types. Based on the presence or absence of overlap between UCN3 and CRFR2 labeling, our data suggest unusual modes of neuromodulation by UCN3, involving volume transmission and autocrine signaling.
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Affiliation(s)
- Sara Pagella
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Jan M Deussing
- Research Group Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Conny Kopp-Scheinpflug
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
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8
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Abstract
Itch is one of the most primal sensations, being both ubiquitous and important for the well-being of animals. For more than a century, a desire to understand how itch is encoded by the nervous system has prompted the advancement of many theories. Within the past 15 years, our understanding of the molecular and neural mechanisms of itch has undergone a major transformation, and this remarkable progress continues today without any sign of abating. Here I describe accumulating evidence that indicates that itch is distinguished from pain through the actions of itch-specific neuropeptides that relay itch information to the spinal cord. According to this model, classical neurotransmitters transmit, inhibit and modulate itch information in a context-, space- and time-dependent manner but do not encode itch specificity. Gastrin-releasing peptide (GRP) is proposed to be a key itch-specific neuropeptide, with spinal neurons expressing GRP receptor (GRPR) functioning as a key part of a convergent circuit for the conveyance of peripheral itch information to the brain.
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9
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Parishar P, Sehgal N, Iyengar S. The expression of delta opioid receptor mRNA in adult male zebra finches (Taenopygia guttata). PLoS One 2021; 16:e0256599. [PMID: 34464410 PMCID: PMC8407588 DOI: 10.1371/journal.pone.0256599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/10/2021] [Indexed: 12/24/2022] Open
Abstract
The endogenous opioid system is evolutionarily conserved across reptiles, birds and mammals and is known to modulate varied brain functions such as learning, memory, cognition and reward. To date, most of the behavioral and anatomical studies in songbirds have mainly focused on μ-opioid receptors (ORs). Expression patterns of δ-ORs in zebra finches, a well-studied species of songbird have not yet been reported, possibly due to the high sequence similarity amongst different opioid receptors. In the present study, a specific riboprobe against the δ-OR mRNA was used to perform fluorescence in situ hybridization (FISH) on sections from the male zebra finch brain. We found that δ-OR mRNA was expressed in different parts of the pallium, basal ganglia, cerebellum and the hippocampus. Amongst the song control and auditory nuclei, HVC (abbreviation used as a formal name) and NIf (nucleus interfacialis nidopallii) strongly express δ-OR mRNA and stand out from the surrounding nidopallium. Whereas the expression of δ-OR mRNA is moderate in LMAN (lateral magnocellular nucleus of the anterior nidopallium), it is low in the MSt (medial striatum), Area X, DLM (dorsolateral nucleus of the medial thalamus), RA (robust nucleus of the arcopallium) of the song control circuit and Field L, Ov (nucleus ovoidalis) and MLd (nucleus mesencephalicus lateralis, pars dorsalis) of the auditory pathway. Our results suggest that δ-ORs may be involved in modulating singing, song learning as well as spatial learning in zebra finches.
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Affiliation(s)
- Pooja Parishar
- National Brain Research Centre, Gurugram, Haryana, India
| | - Neha Sehgal
- National Brain Research Centre, Gurugram, Haryana, India
| | - Soumya Iyengar
- National Brain Research Centre, Gurugram, Haryana, India
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10
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Somatostatin, a Presynaptic Modulator of Glutamatergic Signal in the Central Nervous System. Int J Mol Sci 2021; 22:ijms22115864. [PMID: 34070785 PMCID: PMC8198526 DOI: 10.3390/ijms22115864] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/19/2021] [Accepted: 05/26/2021] [Indexed: 01/07/2023] Open
Abstract
Somatostatin is widely diffused in the central nervous system, where it participates to control the efficiency of synaptic transmission. This peptide mainly colocalizes with GABA, in inhibitory, GABA-containing interneurons from which it is actively released in a Ca2+ dependent manner upon application of depolarizing stimuli. Once released in the synaptic cleft, somatostatin acts locally, or it diffuses in the extracellular space through "volume diffusion", a mechanism(s) of distribution which mainly operates in the cerebrospinal fluid and that assures the progression of neuronal signalling from signal-secreting sender structures towards receptor-expressing targeted neurons located extrasynaptically, in a non-synaptic, inter-neuronal form of communication. Somatostatin controls the efficiency of central glutamate transmission by either modulating presynaptically the glutamate exocytosis or by metamodulating the activity of glutamate receptors colocalized and functionally coupled with somatostatin receptors in selected subpopulations of nerve terminals. Deciphering the role of somatostatin in the mechanisms of "volume diffusion" and in the "receptor-receptor interaction" unveils new perspectives in the central role of this fine tuner of synaptic strength, paving the road to new therapeutic approaches for the cure of central disorders.
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11
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Ruiz-Viroga V, Urbanavicius J, Torterolo P, Lagos P. In vivo uptake of a fluorescent conjugate of melanin-concentrating hormone in the rat brain. J Chem Neuroanat 2021; 114:101959. [PMID: 33848617 DOI: 10.1016/j.jchemneu.2021.101959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 04/03/2021] [Accepted: 04/08/2021] [Indexed: 11/16/2022]
Abstract
Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide synthesized by posterior hypothalamic and incerto-hypothalamic neurons that project throughout the central nervous system. The MCHergic system modulates several important functions such as feeding behavior, mood and sleep. MCH exerts its biological functions through interaction with the MCHR-1 receptor, the only functional receptor present in rodents. The internalization process of MCHR-1 triggered by MCH binding was described in vitro in non-neuronal heterologous systems with over-expression of MCHR-1. Reports of in vivo MCHR-1 internalization dynamics are scarce, however, this is an important process to explore based on the critical functions of the MCHergic system. We had previously determined that 60 min after intracerebroventricular (i.c.v.) microinjections of MCH conjugated with fluorophore rhodamine (R-MCH), the dorsal and median raphe nucleus presented R-MCH positive labeled neurons. In the present work, we further studied the in vivo uptake process focusing on the distribution and time-dependent pattern of R-MCH positive cells 10, 20 and 60 min (T10, T20 and T60, respectively) after i.c.v. microinjection of R-MCH. We also explored this uptake process to see whether it was receptor- and clathrin-dependent and examined the phenotype of R-MCH positive cells and their proximity to MCHergic fibers. We found a great number of R-MCH positive cells with high fluorescence intensity in the lateral septum, nucleus accumbens and hippocampus at T20 and T60 (but not at T10), while a lower number with low intensity was observed in the dorsal raphe nucleus. At T20, in rats pre-treated with a MCHR-1 antagonist (ATC-0175) or with phenylarsine oxide (PAO), a clathrin endocytosis inhibitor, a robust decrease (> 50 %) of R-MCH uptake occurred in these structures. The R-MCH positive cells were identified as neurons (NeuN positive, GFAP negative) and some MCHergic fibers run in the vicinities of them. We concluded that neurons localized at structures that were close to the ventricular surfaces could uptake R-MCH in vivo through a receptor-dependent and clathrin-mediated process. Our results support volume transmission of MCH through the cerebrospinal fluid to reach distant targets. Finally, we propose that R-MCH would be an effective tool to study MCH-uptake in vivo.
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Affiliation(s)
- Vicente Ruiz-Viroga
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Jessika Urbanavicius
- Departamento de Neurofarmacología Experimental, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Pablo Torterolo
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Patricia Lagos
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
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Robayo Avendaño O, Alvira Botero X, Garzón M. Ultrastructural evidence for mu and delta opioid receptors at noradrenergic dendrites and glial profiles in the cat locus coeruleus. Brain Res 2021; 1762:147443. [PMID: 33745926 DOI: 10.1016/j.brainres.2021.147443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/01/2021] [Accepted: 03/13/2021] [Indexed: 11/17/2022]
Abstract
The Locus Coeruleus (LC) is a pontine nucleus involved in many physiological processes, including the control of the sleep/wake cycle (SWC). At cellular level, the LC displays a high density of opioid receptors whose activation decreases the activity of LC noradrenergic neurons. Also, microinjections of morphine administered locally in the LC of the cat produce sleep associated with synchronized brain activity in the electroencephalogram (EEG). Even though much of the research on sleep has been done in the cat, the subcellular location of opioid receptors in the LC and their relationship with LC noradrenergic neurons is not known yet in this species. Therefore, we conducted a study to describe the ultrastructural localization of mu-opioid receptors (MOR), delta-opioid receptors (DOR) and tyrosine hydroxylase (TH) in the cat LC using high resolution electron microscopy double-immunocytochemical detection. MOR and DOR were localized mainly in dendrites (45% and 46% of the total number of profiles respectively), many of which were noradrenergic (35% and 53% for MOR and DOR, respectively). TH immunoreactivity was more frequent in dendrites (65% of the total number of profiles), which mostly also expressed opioid receptors (58% and 73% for MOR and DOR, respectively). Because the distribution of MORs and DORs are similar, it is possible that a substantial sub-population of neurons co-express both receptors, which may facilitate the formation of MOR-DOR heterodimers. Moreover, we found differences in the cat subcellular DOR distribution compared with the rat. This opens the possibility to the existence of diverse mechanisms for opioid modulation of LC activity.
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Affiliation(s)
- Omar Robayo Avendaño
- Universidad Pedagógica y Tecnológica de Colombia. Antiguo Hospital San Rafael, 150001 Tunja, Colombia.
| | - Ximena Alvira Botero
- Universidad Autónoma de Madrid, Calle del Arzobispo Morcillo 4, 28029 Madrid, Spain
| | - Miguel Garzón
- Universidad Autónoma de Madrid, Calle del Arzobispo Morcillo 4, 28029 Madrid, Spain
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13
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Kadhim HJ, Kidd M, Kang SW, Kuenzel WJ. Differential delayed responses of arginine vasotocin and its receptors in septo-hypothalamic brain structures and anterior pituitary that sustain hypothalamic-pituitary-adrenal (HPA) axis functions during acute stress. Gen Comp Endocrinol 2020; 286:113302. [PMID: 31622604 DOI: 10.1016/j.ygcen.2019.113302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/11/2019] [Accepted: 10/13/2019] [Indexed: 10/25/2022]
Abstract
Recently, we proposed that corticotropin releasing hormone (CRH) neurons in the nucleus of hippocampal commissure (NHpC), located in the septum, function as a part of the traditional hypothalamic-pituitary-adrenal (HPA) axis in avian species. CRH and its receptor, CRHR1, are regulated differently in the NHpC compared to the paraventricular nucleus (PVN) following feed deprivation (FD). Therefore, we followed up our work by examining arginine vasotocin (AVT), the other major ACTH secretagogue, and its receptors, V1aR and V1bR, gene expression during FD stress in the NHpC, PVN, and ventral mediobasal hypothalamus/median eminence (MBHv/ME). The objectives were to 1) identify AVT perikarya, fibers and its two major receptors, V1aR and V1bR, in the NHpC, PVN, and MBHv/ME using immunohistochemistry, 2) determine the effect of stress on AVT, V1aR and V1bR mRNA expression in the same three brain structures, NHpC, PVN, and MBHv/ME; and, 3) ascertain the expression pattern of V1aR and V1bR mRNA in the anterior pituitary and measure plasma stress hormone, corticosterone (CORT), concentration following FD stress. Male chicks (Cobb 500), 14 days of age, were divided into six groups (10 birds/treatment) and subjected to different times of FD stress: (Control, 1 h, 2 h, 3 h, 4 h, and 8 h). For each bird, blood, brain, and anterior pituitary were sampled and frozen immediately. The NHpC, PVN, and MBHv/ME were micro-dissected for RT-PCR. Data were analyzed using one-way ANOVA followed by Tukey Kramer HSD test using a significance level of p < 0.05. Perikarya of AVT neurons were identified in the PVN but not in the NHpC nor MBHv/ME, and only V1aR-immunoreactivity (ir) was observed in the three structures, however, gene expression data for AVT and its two receptors were obtained in all structures. Both AVT and V1aR mRNA are expressed and increased significantly in the PVN following FD stress (p < 0.01). For the first time, V1bR mRNA was documented in the avian brain and specifically shown upregulated in the NHpC and PVN (p < 0.01) following stress. Additionally, delayed significant gene expression of AVT and its receptors in the PVN showed a positive feedback relationship responsible for maintaining CORT release. In contrast, a significant downregulation of AVT mRNA and upregulation of V1aR mRNA occurred in the NHpC (p < 0.01) during FD showing a negative feedback relationship between AVT and its receptors, V1aR and V1bR. Within the MBHv/ME and anterior pituitary, a gradual increase of AVT mRNA in PVN as well as MBHv/ME was associated with significant upregulation of V1bR (p < 0. 01) and downregulation of V1aR (p < 0.01) in both MBHv/ME and anterior pituitary indicating AVT regulates its receptors differentially to sustain CORT release and control overstimulation of the anterior pituitary during a stress response.
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Affiliation(s)
- Hakeem J Kadhim
- Center of Excellence in Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - Michael Kidd
- Center of Excellence in Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - Seong W Kang
- Center of Excellence in Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - Wayne J Kuenzel
- Center of Excellence in Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA.
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14
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A Role for The P2Y1 Receptor in Nonsynaptic Cross-depolarization in the Rat Dorsal Root Ganglia. Neuroscience 2019; 423:98-108. [PMID: 31689490 DOI: 10.1016/j.neuroscience.2019.09.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 12/19/2022]
Abstract
Non-synaptic transmission is pervasive throughout the nervous system. It appears especially prevalent in peripheral ganglia, where non-synaptic interactions between neighboring cell bodies have been described in both physiological and pathological conditions, a phenomenon referred to as cross-depolarization (CD) and thought to play a role in sensory processing and chronic pain. CD has been proposed to be mediated by a chemical agent, but its identity has remained elusive. Here, we report that in the rat dorsal root ganglion (DRG), the P2Y1 purinergic receptor (P2RY1) plays an important role in regulating CD. The effect of P2RY1 is cell-type specific: pharmacological blockade of P2RY1 inhibited CD in A-type neurons while enhancing it in C-type neurons. In the nodose ganglion of the vagus, CD requires extracellular calcium in a large percentage of cells. In contrast, we show that in the DRG extracellular calcium appears to play no major role, pointing to a mechanistic difference between the two peripheral ganglia. Furthermore, we show that DRG glial cells also play a cell-type specific role in CD regulation. Fluorocitrate-induced glial inactivation had no effect on A-cells but enhanced CD in C-cells. These findings shed light on the mechanism of CD in the DRG and pave the way for further analysis of non-synaptic neuronal communication in sensory ganglia.
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15
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Distribution of Kiss2 receptor in the brain and its localization in neuroendocrine cells in the zebrafish. Cell Tissue Res 2019; 379:349-372. [PMID: 31471710 DOI: 10.1007/s00441-019-03089-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 08/05/2019] [Indexed: 12/14/2022]
Abstract
Kisspeptin is a hypothalamic neuropeptide, which acts directly on gonadotropin-releasing hormone (GnRH)-secreting neurons via its cognate receptor (GPR54 or Kiss-R) to stimulate GnRH secretion in mammals. In non-mammalian vertebrates, there are multiple kisspeptins (Kiss1 and Kiss2) and Kiss-R types. Recent gene knockout studies have demonstrated that fish kisspeptin systems are not essential in the regulation of reproduction. Studying the detailed distribution of kisspeptin receptor in the brain and pituitary is important for understanding the multiple action sites and potential functions of the kisspeptin system. In the present study, we generated a specific antibody against zebrafish Kiss2-R (=Kiss1Ra/GPR54-1/Kiss-R2/KissR3) and examined its distribution in the brain and pituitary. Kiss2-R-immunoreactive cell bodies are widely distributed in the brain including in the dorsal telencephalon, preoptic area, hypothalamus, optic tectum, and in the hindbrain regions. Double-labeling showed that not all but a subset of preoptic GnRH3 neurons expresses Kiss2-R, while Kiss2-R is expressed in most of the olfactory GnRH3 neurons. In the posterior preoptic region, Kiss2-R immunoreactivity was seen in vasotocin cells. In the pituitary, Kiss2-R immunoreactivity was seen in corticotropes, but not in gonadotropes. The results in this study suggest that Kiss2 and Kiss2-R signaling directly serve non-reproductive functions and indirectly subserve reproductive functions in teleosts.
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16
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Relationship of α-MSH and AgRP axons to the perikarya of melanocortin-4 receptor neurons. Brain Res 2019; 1717:136-146. [DOI: 10.1016/j.brainres.2019.04.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 03/29/2019] [Accepted: 04/18/2019] [Indexed: 11/21/2022]
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17
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Comparing vasopressin and oxytocin fiber and receptor density patterns in the social behavior neural network: Implications for cross-system signaling. Front Neuroendocrinol 2019; 53:100737. [PMID: 30753840 PMCID: PMC7469073 DOI: 10.1016/j.yfrne.2019.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/24/2019] [Accepted: 02/07/2019] [Indexed: 01/23/2023]
Abstract
Vasopressin (AVP) and oxytocin (OXT) regulate social behavior by binding to their canonical receptors, the vasopressin V1a receptor (V1aR) and oxytocin receptor (OTR), respectively. Recent studies suggest that these neuropeptides may also signal via each other's receptors. The extent to which such cross-system signaling occurs likely depends on anatomical overlap between AVP/OXT fibers and V1aR/OTR expression. By comparing AVP/OXT fiber densities with V1aR/OTR binding densities throughout the rat social behavior neural network (SBNN), we propose the potential for cross-system signaling in four regions: the medial amygdala (MeA), bed nucleus of the stria terminalis (BNSTp), medial preoptic area, and periaqueductal grey. We also discuss possible implications of corresponding sex (higher in males versus females) and age (higher in adults versus juveniles) differences in AVP fiber and OTR binding densities in the MeA and BNSTp. Overall, this review reveals the need to unravel the consequences of potential cross-system signaling between AVP and OXT systems in the SBNN for the regulation of social behavior.
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Abstract
The brain hosts a vast and diverse repertoire of neuropeptides, a class of signalling molecules often described as neurotransmitters. Here I argue that this description entails a catalogue of misperceptions, misperceptions that feed into a narrative in which information processing in the brain can be understood only through mapping neuronal connectivity and by studying the transmission of electrically conducted signals through chemical synapses. I argue that neuropeptide signalling in the brain involves primarily autocrine, paracrine and neurohormonal mechanisms that do not depend on synaptic connectivity and that it is not solely dependent on electrical activity but on mechanisms analogous to secretion from classical endocrine cells. As in classical endocrine systems, to understand the role of neuropeptides in the brain, we must understand not only how their release is regulated, but also how their synthesis is regulated and how the sensitivity of their targets is regulated. We must also understand the full diversity of effects of neuropeptides on those targets, including their effects on gene expression.
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Affiliation(s)
- Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Correspondence should be addressed to G Leng:
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19
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Song Z, Albers HE. Cross-talk among oxytocin and arginine-vasopressin receptors: Relevance for basic and clinical studies of the brain and periphery. Front Neuroendocrinol 2018; 51:14-24. [PMID: 29054552 PMCID: PMC5906207 DOI: 10.1016/j.yfrne.2017.10.004] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/07/2017] [Accepted: 10/13/2017] [Indexed: 12/20/2022]
Abstract
Oxytocin (OT) and arginine-vasopressin (AVP) act in the brain to regulate social cognition/social behavior and in the periphery to influence a variety of physiological processes. Although the chemical structures of OT and AVP as well as their receptors are quite similar, OT and AVP can have distinct or even opposing actions. Here, we review the increasing body of evidence that exogenously administered and endogenously released OT and AVP can activate each other's canonical receptors (i.e., cross-talk) and examine the possibility that receptor cross-talk following the synaptic and non-synaptic release of OT and AVP contributes to their distinct roles in the brain and periphery. Understanding the consequences of cross-talk between OT and AVP receptors will be important in identifying how these peptides control social cognition and behavior and for the development of drugs to treat a variety of psychiatric disorders.
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Affiliation(s)
- Zhimin Song
- Center for Behavioral Neuroscience, Neuroscience Institute, Georgia State University, Atlanta, GA 30302, USA
| | - H Elliott Albers
- Center for Behavioral Neuroscience, Neuroscience Institute, Georgia State University, Atlanta, GA 30302, USA.
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20
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Rho HJ, Kim JH, Lee SH. Function of Selective Neuromodulatory Projections in the Mammalian Cerebral Cortex: Comparison Between Cholinergic and Noradrenergic Systems. Front Neural Circuits 2018; 12:47. [PMID: 29988373 PMCID: PMC6023998 DOI: 10.3389/fncir.2018.00047] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/01/2018] [Indexed: 12/15/2022] Open
Abstract
Cortical processing is dynamically modulated by different neuromodulators. Neuromodulation of the cerebral cortex is crucial for maintaining cognitive brain functions such as perception, attention and learning. However, we do not fully understand how neuromodulatory projections are organized in the cerebral cortex to exert various functions. The basal forebrain (BF) cholinergic projection and the locus coeruleus (LC) noradrenergic projection are well-known neuromodulatory projections to the cortex. Decades of studies have identified anatomical and physiological characteristics of these circuits. While both cholinergic and noradrenergic neurons widely project to the cortex, they exhibit different levels of selectivity. Here, we summarize their anatomical and physiological features, highlighting selectivity and specificity of these circuits to different cortical regions. We discuss the importance of selective modulation by comparing their functions in the cortex. We highlight key features in the input-output circuits and target selectivity of these neuromodulatory projections and their roles in controlling four major brain functions: attention, reinforcement, learning and memory, sleep and wakefulness.
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Affiliation(s)
- Hee-Jun Rho
- Sensory Processing Laboratory, Department of Biological Sciences, Korea Advanced Institute of Science & Technology (KAIST), Daejeon, South Korea
| | - Jae-Hyun Kim
- Sensory Processing Laboratory, Department of Biological Sciences, Korea Advanced Institute of Science & Technology (KAIST), Daejeon, South Korea
| | - Seung-Hee Lee
- Sensory Processing Laboratory, Department of Biological Sciences, Korea Advanced Institute of Science & Technology (KAIST), Daejeon, South Korea
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21
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Ou Y, Weber SG. Higher Aminopeptidase Activity Determined by Electroosmotic Push-Pull Perfusion Contributes to Selective Vulnerability of the Hippocampal CA1 Region to Oxygen Glucose Deprivation. ACS Chem Neurosci 2018; 9:535-544. [PMID: 29078045 DOI: 10.1021/acschemneuro.7b00326] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
It has been known for over a century that the hippocampus, the center for learning and memory in the brain, is selectively vulnerable to ischemic damage, with the CA1 being more vulnerable than the CA3. It is also known that leucine enkephalin, or YGGFL, is neuroprotective. We hypothesized that the extracellular hydrolysis of YGGFL may be greater in the CA1 than the CA3, which would lead to the observed difference in susceptibility to ischemia. In rat organotypic hippocampal slice cultures, we estimated the Michaelis constant and the maximum velocity for membrane-bound aminopeptidase activity in the CA1 and CA3 regions. Using electroosmotic push-pull perfusion and offline capillary liquid chromatography, we inferred enzyme activity based on the production rate of GGFL, a natural and inactive product of the enzymatic hydrolysis of YGGFL. We found nearly 3-fold higher aminopeptidase activity in the CA1 than the CA3. The aminopeptidase inhibitor bestatin significantly reduced hydrolysis of YGGFL in both regions by increasing apparent Km. Based on propidium iodide cell death measurements 24 h after oxygen-glucose deprivation, we demonstrate that inhibition of aminopeptidase activity using bestatin selectively protected CA1 against delayed cell death due to oxygen-glucose deprivation and that this neuroprotection occurs through enkephalin-dependent pathways.
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Affiliation(s)
- Yangguang Ou
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Stephen G. Weber
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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22
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Diao F, Elliott AD, Diao F, Shah S, White BH. Neuromodulatory connectivity defines the structure of a behavioral neural network. eLife 2017; 6:29797. [PMID: 29165248 PMCID: PMC5720592 DOI: 10.7554/elife.29797] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022] Open
Abstract
Neural networks are typically defined by their synaptic connectivity, yet synaptic wiring diagrams often provide limited insight into network function. This is due partly to the importance of non-synaptic communication by neuromodulators, which can dynamically reconfigure circuit activity to alter its output. Here, we systematically map the patterns of neuromodulatory connectivity in a network that governs a developmentally critical behavioral sequence in Drosophila. This sequence, which mediates pupal ecdysis, is governed by the serial release of several key factors, which act both somatically as hormones and within the brain as neuromodulators. By identifying and characterizing the functions of the neuronal targets of these factors, we find that they define hierarchically organized layers of the network controlling the pupal ecdysis sequence: a modular input layer, an intermediate central pattern generating layer, and a motor output layer. Mapping neuromodulatory connections in this system thus defines the functional architecture of the network. Why do animals behave the way they do? Behavior occurs in response to signals from the environment, such as those indicating food or danger, or signals from the body, such as those indicating hunger or thirst. The nervous system detects these signals and triggers an appropriate response, such as seeking food or fleeing a threat. But because much of the nervous system takes part in generating these responses, it can make it difficult to understand how even simple behaviors come about. One behavior that has been studied extensively is molting in insects. Molting enables insects to grow and develop, and involves casting off the outer skeleton of the previous developmental stage. To do this, the insect performs a series of repetitive movements, known as an ecdysis sequence. In the fruit fly, the pupal ecdysis sequence consists of three distinct patterns rhythmic abdominal movement. A hormone called ecdysis triggering hormone, or ETH for short, initiates this sequence by triggering the release of two further hormones, Bursicon and CCAP. All three hormones act on the nervous system to coordinate molting behavior, but exactly how they do so is unclear. Diao et al. have now used genetic tools called Trojan exons to identify the neurons of fruit flies on which these hormones act. Trojan exons are short sequences of DNA that can be inserted into non-coding regions of a target gene to mark or manipulate the cells that express it. When a cell uses its copy of the target gene to make a protein, it also makes the product encoded by the Trojan exon. Using this technique, Diao et al. identified three sets of neurons that produce receptor proteins that recognize the molting hormones. Neurons with ETH receptors start the molting process by activating neurons that make Bursicon and CCAP. Neurons with Bursicon receptors then generate motor rhythms within the nervous system. Finally, neurons with CCAP receptors respond to these rhythms and produce the abdominal movements of the ecdysis sequence. Many other animal behaviors depend on substances like ETH, Bursicon and CCAP, which act within the brain to change the activity of neurons and circuits. The work of Diao et al. suggests that identifying the sites at which such substances act can help reveal the circuits that govern complex behaviors.
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Affiliation(s)
- Feici Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, United States
| | - Amicia D Elliott
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, United States
| | - Fengqiu Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, United States
| | - Sarav Shah
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, United States
| | - Benjamin H White
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, United States
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23
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Palacios JM, Mengod G. Receptor visualization and the atomic bomb. A historical account of the development of the chemical neuroanatomy of receptors for neurotransmitters and drugs during the Cold War. J Chem Neuroanat 2017; 88:76-112. [PMID: 28755996 DOI: 10.1016/j.jchemneu.2017.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 07/13/2017] [Indexed: 01/24/2023]
Abstract
This is a historical account of how receptors for neurotransmitters and drugs got to be seen at the regional, cellular, and subcellular levels in brain, in the years going from the end of the World War II until the collapse of the Soviet Union, the Cold War (1945-1991). The realization in the US of the problem of mental health care, as a consequence of the results of medical evaluation for military service during the war, let the US Government to act creating among other things the National Institute for Mental Health (NIMH). Coincident with that, new drug treatments for these disorders were introduced. War science also created an important number of tools and instruments, such as the radioisotopes, that played a significant role in the development of our story. The scientific context was marked by the development of Biochemistry, Molecular Biology and the introduction in the early 80's of the DNA recombinant technologies. The concepts of chemical neurotransmission in the brain and of receptors for drugs and transmitters, although proposed before the war, where not generally accepted. Neurotransmitters were identified and the mechanisms of biosynthesis, storage, release and termination of action by mechanisms such as reuptake, elucidated. Furthermore, the synapse was seen with the electron microscope and more important for our account, neurons and their processes visualized in the brain first by fluorescence histochemistry, then using radioisotopes and autoradiography, and later by immunohistochemistry (IHC), originating the Chemical Neuroanatomy. The concept of chemical neurotransmission evolved from the amines, expanded to excitatory and inhibitory amino acids, then to neuropeptides and finally to gases and other "atypical" neurotransmitters. In addition, coexpression of more than one transmitter in a neuron, changed the initial ideas of neurotransmission. The concept of receptors for these and other messengers underwent a significant evolution from an abstract chemical concept to their physical reality as gene products. Important steps were the introduction in the 70's of radioligand binding techniques and the cloning of receptor genes in the 80's. Receptors were first visualized using radioligands and autoradiography, and analyzed with the newly developed computer-assisted image analysis systems. Using Positron Emission Tomography transmitters and receptors were visualized in living human brain. The cloning of receptor genes allowed the use of in situ hybridization histochemistry and immunohistochemistry to visualize with the light and electron microscopes the receptor mRNAs and proteins. The results showed the wide heterogeneity of receptors and the diversity of mode of signal transmission, synaptic and extra-synaptic, again radically modifying the early views of neurotransmission. During the entire period the interplay between basic science and Psychopharmacology and Psychiatry generated different transmitter or receptor-based theories of brain drug action. These concepts and technologies also changed the way new drugs were discovered and developed. At the end of the period, a number of declines in these theories, the use of certain tools and the ability to generate new diagnostics and treatments, the end of an era and the beginning of a new one in the research of how the brain functions.
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Affiliation(s)
| | - G Mengod
- IIBB-CSIC, IDIBAPS, CIBERNED, Barcelona, Spain
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24
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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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25
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Kononenko O, Galatenko V, Andersson M, Bazov I, Watanabe H, Zhou XW, Iatsyshyna A, Mityakina I, Yakovleva T, Sarkisyan D, Ponomarev I, Krishtal O, Marklund N, Tonevitsky A, Adkins DL, Bakalkin G. Intra- and interregional coregulation of opioid genes: broken symmetry in spinal circuits. FASEB J 2017; 31:1953-1963. [PMID: 28122917 DOI: 10.1096/fj.201601039r] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 01/09/2017] [Indexed: 12/31/2022]
Abstract
Regulation of the formation and rewiring of neural circuits by neuropeptides may require coordinated production of these signaling molecules and their receptors that may be established at the transcriptional level. Here, we address this hypothesis by comparing absolute expression levels of opioid peptides with their receptors, the largest neuropeptide family, and by characterizing coexpression (transcriptionally coordinated) patterns of these genes. We demonstrated that expression patterns of opioid genes highly correlate within and across functionally and anatomically different areas. Opioid peptide genes, compared with their receptor genes, are transcribed at much greater absolute levels, which suggests formation of a neuropeptide cloud that covers the receptor-expressed circuits. Surprisingly, we found that both expression levels and the proportion of opioid receptors are strongly lateralized in the spinal cord, interregional coexpression patterns are side specific, and intraregional coexpression profiles are affected differently by left- and right-side unilateral body injury. We propose that opioid genes are regulated as interconnected components of the same molecular system distributed between distinct anatomic regions. The striking feature of this system is its asymmetric coexpression patterns, which suggest side-specific regulation of selective neural circuits by opioid neurohormones.-Kononenko, O., Galatenko, V., Andersson, M., Bazov, I., Watanabe, H., Zhou, X. W., Iatsyshyna, A., Mityakina, I., Yakovleva, T., Sarkisyan, D., Ponomarev, I., Krishtal, O., Marklund, N., Tonevitsky, A., Adkins, D. L., Bakalkin, G. Intra- and interregional coregulation of opioid genes: broken symmetry in spinal circuits.
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Affiliation(s)
- Olga Kononenko
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.,Key State Laboratory, Bogomoletz Institute of Physiology, Kiev, Ukraine
| | | | - Malin Andersson
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Igor Bazov
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden;
| | - Hiroyuki Watanabe
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Xing Wu Zhou
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Anna Iatsyshyna
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.,Department of Human Genetics, Institute of Molecular Biology and Genetics, Kiev, Ukraine
| | | | - Tatiana Yakovleva
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Daniil Sarkisyan
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Igor Ponomarev
- Waggoner Center for Alcohol and Addiction Research and The College of Pharmacy, The University of Texas, Austin, Texas, USA
| | - Oleg Krishtal
- Key State Laboratory, Bogomoletz Institute of Physiology, Kiev, Ukraine
| | - Niklas Marklund
- Department of Neuroscience, Section of Neurosurgery, Uppsala University Hospital, Uppsala, Sweden
| | | | - DeAnna L Adkins
- Department of Neuroscience, College of Medicine, and.,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Georgy Bakalkin
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
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Mitre M, Marlin BJ, Schiavo JK, Morina E, Norden SE, Hackett TA, Aoki CJ, Chao MV, Froemke RC. A Distributed Network for Social Cognition Enriched for Oxytocin Receptors. J Neurosci 2016; 36:2517-35. [PMID: 26911697 PMCID: PMC4764667 DOI: 10.1523/jneurosci.2409-15.2016] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 01/08/2023] Open
Abstract
Oxytocin is a neuropeptide important for social behaviors such as maternal care and parent-infant bonding. It is believed that oxytocin receptor signaling in the brain is critical for these behaviors, but it is unknown precisely when and where oxytocin receptors are expressed or which neural circuits are directly sensitive to oxytocin. To overcome this challenge, we generated specific antibodies to the mouse oxytocin receptor and examined receptor expression throughout the brain. We identified a distributed network of female mouse brain regions for maternal behaviors that are especially enriched for oxytocin receptors, including the piriform cortex, the left auditory cortex, and CA2 of the hippocampus. Electron microscopic analysis of the cerebral cortex revealed that oxytocin receptors were mainly expressed at synapses, as well as on axons and glial processes. Functionally, oxytocin transiently reduced synaptic inhibition in multiple brain regions and enabled long-term synaptic plasticity in the auditory cortex. Thus modulation of inhibition may be a general mechanism by which oxytocin can act throughout the brain to regulate parental behaviors and social cognition.
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Affiliation(s)
- Mariela Mitre
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Department of Otolaryngology, Department of Neuroscience and Physiology
| | - Bianca J Marlin
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Department of Otolaryngology, Department of Neuroscience and Physiology
| | - Jennifer K Schiavo
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Department of Otolaryngology, Department of Neuroscience and Physiology
| | - Egzona Morina
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Department of Otolaryngology, Department of Neuroscience and Physiology
| | - Samantha E Norden
- Skirball Institute for Biomolecular Medicine, Department of Cell Biology, and Department of Psychiatry, New York University School of Medicine, New York, New York 10016
| | - Troy A Hackett
- Vanderbilt Kennedy Center for Research on Human Development, Department of Hearing and Speech Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, and
| | - Chiye J Aoki
- Center for Neural Science, New York University, New York, New York 10003
| | - Moses V Chao
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Department of Neuroscience and Physiology, Department of Cell Biology, and Department of Psychiatry, New York University School of Medicine, New York, New York 10016, Center for Neural Science, New York University, New York, New York 10003
| | - Robert C Froemke
- Skirball Institute for Biomolecular Medicine, Neuroscience Institute, Department of Otolaryngology, Department of Neuroscience and Physiology, Center for Neural Science, New York University, New York, New York 10003
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Devan BD, Chaban N, Piscopello J, Deibel SH, McDonald RJ. Cognitive and Stimulus–Response Habit Functions of the Neo-(Dorsal) Striatum. INNOVATIONS IN COGNITIVE NEUROSCIENCE 2016. [DOI: 10.1007/978-3-319-42743-0_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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28
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Exploring the role of neuropeptide S in the regulation of arousal: a functional anatomical study. Brain Struct Funct 2015; 221:3521-46. [PMID: 26462664 DOI: 10.1007/s00429-015-1117-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/18/2015] [Indexed: 12/13/2022]
Abstract
Neuropeptide S (NPS) is a regulatory peptide expressed by limited number of neurons in the brainstem. The simultaneous anxiolytic and arousal-promoting effect of NPS suggests an involvement in mood control and vigilance, making the NPS-NPS receptor system an interesting potential drug target. Here we examined, in detail, the distribution of NPS-immunoreactive (IR) fiber arborizations in brain regions of rat known to be involved in the regulation of sleep and arousal. Such nerve terminals were frequently apposed to GABAergic/galaninergic neurons in the ventro-lateral preoptic area (VLPO) and to tyrosine hydroxylase-IR neurons in all hypothalamic/thalamic dopamine cell groups. Then we applied the single platform-on-water (mainly REM) sleep deprivation method to study the functional role of NPS in the regulation of arousal. Of the three pontine NPS cell clusters, the NPS transcript levels were increased only in the peri-coerulear group in sleep-deprived animals, but not in stress controls. The density of NPS-IR fibers was significantly decreased in the median preoptic nucleus-VLPO region after the sleep deprivation, while radioimmunoassay and mass spectrometry measurements showed a parallel increase of NPS in the anterior hypothalamus. The expression of the NPS receptor was, however, not altered in the VLPO-region. The present results suggest a selective activation of one of the three NPS-expressing neuron clusters as well as release of NPS in distinct forebrain regions after sleep deprivation. Taken together, our results emphasize a role of the peri-coerulear cluster in the modulation of arousal, and the importance of preoptic area for the action of NPS on arousal and sleep.
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29
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Melanin-concentrating hormone neurons release glutamate for feedforward inhibition of the lateral septum. J Neurosci 2015; 35:3644-51. [PMID: 25716862 DOI: 10.1523/jneurosci.4187-14.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Melanin-concentrating hormone (MCH) regulates vital physiological functions, including energy balance and sleep. MCH cells are thought to be GABAergic, releasing GABA to inhibit downstream targets. However, there is little experimental support for this paradigm. To better understand the synaptic mechanisms of mouse MCH neurons, we performed neuroanatomical mapping and characterization followed by optogenetics to test their functional connectivity at downstream targets. Synaptophysin-mediated projection mapping showed that the lateral septal nucleus (LS) contained the densest accumulation of MCH nerve terminals. We then expressed channel rhodopsin-2 in MCH neurons and photostimulated MCH projections to determine their effect on LS activity. Photostimulation of MCH projections evoked a monosynaptic glutamate release in the LS. Interestingly, this led to a feedforward inhibition that depressed LS firing by a robust secondary GABA release. This study presents a circuit analysis between MCH and LS neurons and confirms their functional connection via monosynaptic and polysynaptic pathways. Our findings indicate that MCH neurons are not exclusively GABAergic and reveal a glutamate-mediated, feedforward mechanism that inhibits LS cells.
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Bach-y-Rita P. Theoretical and Practical Considerations in the Restoration of Function After Stroke. Top Stroke Rehabil 2015; 8:1-15. [PMID: 14523734 DOI: 10.1310/8t1t-etxu-8pdf-9x7f] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recovery of function after stroke appears to include elements of both restoration and compensation. The brain is highly plastic, which allows reorganization after damage. Stroke produces permanent damage to the brain, so recovery must be based on activity in surviving cells that are either adjacent, contralateral, or in a different region. Furthermore, representation of a particular function in the brain is usually not limited to a single brain region. Multiple representation provides the opportunity for brain reorganization; functions are assumed by surviving brain structures. Compensation can be the initial response in the recovery phase and may persist through later phases because of the new habits formed (as the restraint therapy studies of Taub and others would suggest), because the damage to the brain is extensive and hinders restoration, because of secondary pathology, such as tendon shortening and muscle wasting, that does not allow brain reorganization to be translated into functional recovery, or because of inadequate (especially late) rehabilitation.
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Affiliation(s)
- P Bach-y-Rita
- Department of Rehabilitation Medicine, University of Wisconsin-Madison, USA
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31
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Albers HE. Species, sex and individual differences in the vasotocin/vasopressin system: relationship to neurochemical signaling in the social behavior neural network. Front Neuroendocrinol 2015; 36:49-71. [PMID: 25102443 PMCID: PMC4317378 DOI: 10.1016/j.yfrne.2014.07.001] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/23/2014] [Accepted: 07/27/2014] [Indexed: 11/16/2022]
Abstract
Arginine-vasotocin (AVT)/arginine vasopressin (AVP) are members of the AVP/oxytocin (OT) superfamily of peptides that are involved in the regulation of social behavior, social cognition and emotion. Comparative studies have revealed that AVT/AVP and their receptors are found throughout the "social behavior neural network (SBNN)" and display the properties expected from a signaling system that controls social behavior (i.e., species, sex and individual differences and modulation by gonadal hormones and social factors). Neurochemical signaling within the SBNN likely involves a complex combination of synaptic mechanisms that co-release multiple chemical signals (e.g., classical neurotransmitters and AVT/AVP as well as other peptides) and non-synaptic mechanisms (i.e., volume transmission). Crosstalk between AVP/OT peptides and receptors within the SBNN is likely. A better understanding of the functional properties of neurochemical signaling in the SBNN will allow for a more refined examination of the relationships between this peptide system and species, sex and individual differences in sociality.
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Affiliation(s)
- H Elliott Albers
- Center for Behavioral Neuroscience, Neuroscience Institute, Georgia State University, Atlanta, GA 30302, USA.
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32
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Selvam R, Jurkevich A, Kuenzel WJ. Distribution of the vasotocin type 4 receptor throughout the brain of the chicken,Gallus gallus. J Comp Neurol 2014; 523:335-58. [DOI: 10.1002/cne.23684] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 09/21/2014] [Accepted: 09/23/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Rajamani Selvam
- Center of Excellence for Poultry Science; University of Arkansas; Fayetteville Arkansas 72701
| | - Alexander Jurkevich
- Molecular Cytology Research Core Facility; University of Missouri; Columbia Missouri 65211
| | - Wayne J. Kuenzel
- Center of Excellence for Poultry Science; University of Arkansas; Fayetteville Arkansas 72701
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33
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Gu G, Roland B, Tomaselli K, Dolman CS, Lowe C, Heilig JS. Glucagon-like peptide-1 in the rat brain: distribution of expression and functional implication. J Comp Neurol 2013; 521:2235-61. [PMID: 23238833 DOI: 10.1002/cne.23282] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 09/17/2012] [Accepted: 12/07/2012] [Indexed: 12/20/2022]
Abstract
Glucagon-like-peptide 1 (GLP-1) is expressed not only in gut endocrine cells, but also in cells in the caudal brainstem and taste buds. To better understand the functions of central GLP-1, GLP-1 expression was immunohistochemically profiled in normal rat brain and its distribution correlated with FOS induction following systemic administration of a GLP-1 receptor agonist, exendin-4. In the present study, only a small number of GLP-1-immunoreactive cell bodies were observed in the nucleus of the solitary tract (NTS). However, these neurons send abundant projections to other regions of the brain, in particular the forebrain, including the paraventricular and dorsomedial nuclei of the hypothalamus, the central nucleus of the amygdala, the oval nucleus of the bed nuclei of the stria terminalis, and the paraventricular nucleus of the thalamus. Intraperitoneal administration of exendin-4 resulted in extensive FOS expression in areas of the forebrain and the hindbrain. In the forebrain, FOS expression was largely confined to regions where a high density of GLP-1-immunoreactive terminals was also localized. The majority of GLP-1-immunoreactive cells in the NTS were not FOS-positive. FOS-positive cells appeared to represent a different population from those expressing GLP-1. Thus, GLP-1-containing neurons in the brainstem may not be involved in receiving and relaying to other regions of the brain the physiological signals of prandial GLP-1 secreted by intestinal L-cells. Projections of GLP-1-containing neurons to the distinctive structures in the forebrain imply that central GLP-1 may play an important role in the behavioral and metabolic integration of autonomic control and arousal in the rat.
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Affiliation(s)
- Guibao Gu
- Amylin Pharmaceuticals, San Diego, California 92121, USA.
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34
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Griffith LC. Neuromodulatory control of sleep in Drosophila melanogaster: integration of competing and complementary behaviors. Curr Opin Neurobiol 2013; 23:819-23. [PMID: 23743247 DOI: 10.1016/j.conb.2013.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/07/2013] [Accepted: 05/14/2013] [Indexed: 12/11/2022]
Abstract
The transition between wake and sleep states is characterized by rapid and generalized changes in both sensory and motor processing. Sleep is antagonistic to the expression of important behaviors, like feeding, reproduction and learning whose relative importance to an individual will depend on its circumstances at that moment. An understanding of how the decision to sleep is affected by these other drives and how this process is coordinated across the entire brain remains elusive. Neuromodulation is an important regulatory feature of many behavioral circuits and the reconfiguring of these circuits by modulators can have both long-term and short-term consequences. Drosophila melanogaster has become an important model system for understanding the molecular and genetic bases of behaviors and in recent years neuromodulatory systems have been shown to play a major role in regulation of sleep and other behaviors in this organism. The fly, with its increasingly well-defined behavioral circuitry and powerful genetic tools, is a system poised to provide new insight into the complex issue of how neuromodulation can coordinate situation-specific behavioral needs with the brain's arousal state.
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Affiliation(s)
- Leslie C Griffith
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, MS008, 415 South Street, Waltham, MA 02454-9110, USA.
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35
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Veening JG, Olivier B. Intranasal administration of oxytocin: behavioral and clinical effects, a review. Neurosci Biobehav Rev 2013; 37:1445-65. [PMID: 23648680 PMCID: PMC7112651 DOI: 10.1016/j.neubiorev.2013.04.012] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 04/22/2013] [Accepted: 04/24/2013] [Indexed: 12/11/2022]
Abstract
The mechanisms behind the effects of IN-applied substances need more attention. The mechanisms involved in the brain-distribution of IN-OT are completely unexplored. The possibly cascading effects of IN-OT on the intrinsic OT-system require serious investigation. IN-OT induces clear and specific changes in neural activation. IN-OT is a promising approach to treat certain clinical symptoms.
The intranasal (IN-) administration of substances is attracting attention from scientists as well as pharmaceutical companies. The effects are surprisingly fast and specific. The present review explores our current knowledge about the routes of access to the cranial cavity. ‘Direct-access-pathways’ from the nasal cavity have been described but many additional experiments are needed to answer a variety of open questions regarding anatomy and physiology. Among the IN-applied substances oxytocin (OT) has an extensive history. Originally applied in women for its physiological effects related to lactation and parturition, over the last decade most studies focused on their behavioral ‘prosocial’ effects: from social relations and ‘trust’ to treatment of ‘autism’. Only very recently in a microdialysis study in rats and mice, the ‘direct-nose-brain-pathways’ of IN-OT have been investigated directly, implying that we are strongly dependent on results obtained from other IN-applied substances. Especially the possibility that IN-OT activates the ‘intrinsic’ OT-system in the hypothalamus as well needs further clarification. We conclude that IN-OT administration may be a promising approach to influence human communication but that the existing lack of information about the neural and physiological mechanisms involved is a serious problem for the proper understanding and interpretation of the observed effects.
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Affiliation(s)
- Jan G Veening
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands; Department of Anatomy (109), Radboud University of Medical Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
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36
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Otero-Garcia M, Martin-Sanchez A, Fortes-Marco L, Martínez-Ricós J, Agustin-Pavón C, Lanuza E, Martínez-García F. Extending the socio-sexual brain: arginine-vasopressin immunoreactive circuits in the telencephalon of mice. Brain Struct Funct 2013; 219:1055-81. [PMID: 23625152 DOI: 10.1007/s00429-013-0553-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 04/11/2013] [Indexed: 12/30/2022]
Abstract
Quantitative analysis of the immunoreactivity for arginine-vasopressin (AVP-ir) in the telencephalon of male (intact and castrated) and female CD1 mice allows us to precisely locate two sexually dimorphic (more abundant in intact than castrated males and females) AVP-ir cell groups in the posterior bed nucleus of the stria terminalis (BST) and the amygdala. Chemoarchitecture (NADPH diaphorase) reveals that the intraamygdaloid AVP-ir cells are located in the intra-amygdaloid BST (BSTIA) rather than the medial amygdala (Me), as previously thought. Then, we have used for the first time tract tracing (combined with AVP immunofluorescence) and fiber-sparing lesions of the BST to analyze the projections of the telencephalic AVP-ir cell groups. The results demonstrate that the posterior BST originates the sexually dimorphic innervation of the lateral septum, the posterodorsal Me and a substance P-negative area in the medioventral striato-pallidum (mvStP).The BSTIA may also contribute to some of these terminal fields. Our material also reveals non-dimorphic AVP-ir processes in two locations of the amygdala. First, the ventral Me shows dendrite-like AVP-ir processes apparently belonging supraoptic neurons, whose possible functions are discussed. Second, the Ce shows sparse, thick AVP-ir axons with high individual variability in density and distribution, whose possible influence on stress coping in relation to the affiliative or agonistic behaviors mediated by the Me are discussed. Finally, we propose that the region of the mvStP showing sexually dimorphic AVP-ir innervation is part of the brain network for socio-sexual behavior, in which it would mediate motivational aspects of chemosensory-guided social interactions.
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Affiliation(s)
- Marcos Otero-Garcia
- Laboratori de Neuroanatomia Funcional Comparada, Depts. Biologia Funcional i Biologia Cel·lular, Fac. Ciències Biològiques, Univ. València, C. Dr. Moliner, 50, 46100, Burjassot, Spain
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Abstract
Neuropeptides are found in many mammalian CNS neurons where they play key roles in modulating neuronal activity. In contrast to amino acid transmitter release at the synapse, neuropeptide release is not restricted to the synaptic specialization, and after release, a neuropeptide may diffuse some distance to exert its action through a G protein-coupled receptor. Some neuropeptides such as hypocretin/orexin are synthesized only in single regions of the brain, and the neurons releasing these peptides probably have similar functional roles. Other peptides such as neuropeptide Y (NPY) are synthesized throughout the brain, and neurons that synthesize the peptide in one region have no anatomical or functional connection with NPY neurons in other brain regions. Here, I review converging data revealing a complex interaction between slow-acting neuromodulator peptides and fast-acting amino acid transmitters in the control of energy homeostasis, drug addiction, mood and motivation, sleep-wake states, and neuroendocrine regulation.
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Volume transmission of beta-endorphin via the cerebrospinal fluid; a review. Fluids Barriers CNS 2012; 9:16. [PMID: 22883598 PMCID: PMC3439317 DOI: 10.1186/2045-8118-9-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 07/07/2012] [Indexed: 02/08/2023] Open
Abstract
There is increasing evidence that non-synaptic communication by volume transmission in the flowing CSF plays an important role in neural mechanisms, especially for extending the duration of behavioral effects. In the present review, we explore the mechanisms involved in the behavioral and physiological effects of β-endorphin (β-END), especially those involving the cerebrospinal fluid (CSF), as a message transport system to reach distant brain areas. The major source of β-END are the pro-opio-melano-cortin (POMC) neurons, located in the arcuate hypothalamic nucleus (ARH), bordering the 3rd ventricle. In addition, numerous varicose β-END-immunoreactive fibers are situated close to the ventricular surfaces. In the present paper we surveyed the evidence that volume transmission via the CSF can be considered as an option for messages to reach remote brain areas. Some of the points discussed in the present review are: release mechanisms of β-END, independence of peripheral versus central levels, central β-END migration over considerable distances, behavioral effects of β-END depend on location of ventricular administration, and abundance of mu and delta opioid receptors in the periventricular regions of the brain.
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Stevenson EL, Caldwell HK. The vasopressin 1b receptor and the neural regulation of social behavior. Horm Behav 2012; 61:277-82. [PMID: 22178035 PMCID: PMC3310934 DOI: 10.1016/j.yhbeh.2011.11.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 11/25/2011] [Accepted: 11/28/2011] [Indexed: 12/24/2022]
Abstract
To date, much of the work in rodents implicating vasopressin (Avp) in the regulation of social behavior has focused on its action via the Avp 1a receptor (Avpr1a). However, there is mounting evidence that the Avp 1b receptor (Avpr1b) also plays a significant role in Avp's modulation of social behavior. The Avpr1b is heavily expressed on the anterior pituitary cortiocotrophs where it acts as an important modulator of the endocrine stress response. In the brain, the Avpr1b is prominent in the CA2 region of the hippocampus, but can also be found in areas such as the paraventricular nucleus of the hypothalamus and the olfactory bulb. Studies that have employed genetic knockouts or pharmacological manipulation of the Avpr1b point to the importance of central Avpr1b in the modulation of social behavior. However, there continues to be a knowledge gap in our understanding of where in the brain this is occurring, as well as how and if the central actions of Avp acting via the Avpr1b interact with the stress axis. In this review we focus on the genetic and pharmacological studies that have implicated the Avpr1b in the neural regulation of social behaviors, including social forms of aggressive behavior, social memory, and social motivation. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.
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Affiliation(s)
- Erica L Stevenson
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH 44242,, USA
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40
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Hazell GG, Hindmarch CC, Pope GR, Roper JA, Lightman SL, Murphy D, O’Carroll AM, Lolait SJ. G protein-coupled receptors in the hypothalamic paraventricular and supraoptic nuclei--serpentine gateways to neuroendocrine homeostasis. Front Neuroendocrinol 2012; 33:45-66. [PMID: 21802439 PMCID: PMC3336209 DOI: 10.1016/j.yfrne.2011.07.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 06/24/2011] [Accepted: 07/06/2011] [Indexed: 12/31/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in the mammalian genome. They are activated by a multitude of different ligands that elicit rapid intracellular responses to regulate cell function. Unsurprisingly, a large proportion of therapeutic agents target these receptors. The paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus are important mediators in homeostatic control. Many modulators of PVN/SON activity, including neurotransmitters and hormones act via GPCRs--in fact over 100 non-chemosensory GPCRs have been detected in either the PVN or SON. This review provides a comprehensive summary of the expression of GPCRs within the PVN/SON, including data from recent transcriptomic studies that potentially expand the repertoire of GPCRs that may have functional roles in these hypothalamic nuclei. We also present some aspects of the regulation and known roles of GPCRs in PVN/SON, which are likely complemented by the activity of 'orphan' GPCRs.
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Affiliation(s)
| | | | | | | | | | | | | | - Stephen J. Lolait
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Dorothy Hodgkin Building, School of Clinical Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
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41
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Dopamine D5 receptors are localized at asymmetric synapses in the rat hippocampus. Neuroscience 2011; 192:164-71. [DOI: 10.1016/j.neuroscience.2011.06.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/27/2011] [Accepted: 06/18/2011] [Indexed: 01/22/2023]
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42
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Bucher D, Goaillard JM. Beyond faithful conduction: short-term dynamics, neuromodulation, and long-term regulation of spike propagation in the axon. Prog Neurobiol 2011; 94:307-46. [PMID: 21708220 PMCID: PMC3156869 DOI: 10.1016/j.pneurobio.2011.06.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 05/27/2011] [Accepted: 06/07/2011] [Indexed: 12/13/2022]
Abstract
Most spiking neurons are divided into functional compartments: a dendritic input region, a soma, a site of action potential initiation, an axon trunk and its collaterals for propagation of action potentials, and distal arborizations and terminals carrying the output synapses. The axon trunk and lower order branches are probably the most neglected and are often assumed to do nothing more than faithfully conducting action potentials. Nevertheless, there are numerous reports of complex membrane properties in non-synaptic axonal regions, owing to the presence of a multitude of different ion channels. Many different types of sodium and potassium channels have been described in axons, as well as calcium transients and hyperpolarization-activated inward currents. The complex time- and voltage-dependence resulting from the properties of ion channels can lead to activity-dependent changes in spike shape and resting potential, affecting the temporal fidelity of spike conduction. Neural coding can be altered by activity-dependent changes in conduction velocity, spike failures, and ectopic spike initiation. This is true under normal physiological conditions, and relevant for a number of neuropathies that lead to abnormal excitability. In addition, a growing number of studies show that the axon trunk can express receptors to glutamate, GABA, acetylcholine or biogenic amines, changing the relative contribution of some channels to axonal excitability and therefore rendering the contribution of this compartment to neural coding conditional on the presence of neuromodulators. Long-term regulatory processes, both during development and in the context of activity-dependent plasticity may also affect axonal properties to an underappreciated extent.
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Affiliation(s)
- Dirk Bucher
- The Whitney Laboratory and Department of Neuroscience, University of Florida, St. Augustine, FL 32080, USA.
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43
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Harigai Y, Natsume M, Li F, Ohtani A, Senzaki K, Shiga T. Differential roles of calcitonin family peptides in the dendrite formation and spinogenesis of the cerebral cortex in vitro. Neuropeptides 2011; 45:263-72. [PMID: 21549427 DOI: 10.1016/j.npep.2011.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/08/2011] [Accepted: 04/11/2011] [Indexed: 11/26/2022]
Abstract
We examined roles of calcitonin family peptides in the initial stages of dendrite formation and the maturation of dendritic spines in the rat cerebral cortex in vitro. Embryonic day 18 cortical neurons were dissociated and cultured for 2-3days in the presence of calcitonin gene-related peptide (CGRP), calcitonin, amylin or adrenomedullin. The treatment of cortical neurons with CGRP promoted the formation of primary dendrites of non-GABAergic neurons. In contrast, the treatment with amylin and adrenomedullin for 3days inhibited the dendritic elongation of non-GABAergic neurons. Calcitonin had no effect on the initial dendrite formation. Next, we examined roles of the peptides in the spine formation. Embryonic day 16 cortical neurons were cultured for 14days and then treated acutely with CGRP, amylin or adrenomedullin for 24h. The density of filopodia, puncta/stubby spines and spines were increased by the CGRP treatment, whereas decreased by amylin. Therefore, CGRP and amylin showed opposite effects on the formation of dendritic filopodia, puncta and spines. Adrenomedullin had no effects on the spine formation. In conclusion, the present study showed that calcitonin family peptides have differential effects both in the dendrite formation during the initial stages and the spine formation of cortical neurons in vitro.
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Affiliation(s)
- Yuichi Harigai
- University of Tsukuba, Graduate School of Comprehensive Human Sciences, Doctoral Program in Kansei, Behavioral and Brain Sciences, Tennodai, Japan
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44
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Le Maître TW, Xia S, Le Maitre E, Dun XP, Lu J, Theodorsson E, Ogren SO, Hökfelt T, Xu ZQD. Galanin receptor 2 overexpressing mice display an antidepressive-like phenotype: possible involvement of the subiculum. Neuroscience 2011; 190:270-88. [PMID: 21672612 DOI: 10.1016/j.neuroscience.2011.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 04/21/2011] [Accepted: 05/04/2011] [Indexed: 01/13/2023]
Abstract
The behavioral phenotype of a transgenic mouse overexpressing a galanin receptor 2 (GalR2)-enhanced, green fluorescent protein (EGFP)-construct under the platelet-derived growth factor-B promoter, and of controls, was assessed in various behavioral tests, such as the Porsolt forced swim test, as well as the open field, elevated plus maze and passive avoidance tests. In addition, the distribution of GalR2-EGFP expressing cell bodies and processes was studied in the brain of these mice using histochemical methods. Three age groups of the transgenic mice demonstrated decreased levels of immobility in the forced swim test, indicative of antidepressive-like behavior and/or increased stress resistance. Anxiety-like behaviors, measured in two different tests, did not differ between the GalR2-overexpressing and the wild-type mice, nor did motor activity levels, emotional learning or memory behaviors. High levels of GalR2 mRNA and protein expression were observed in the presubiculum, subiculum, cingulate cortex, retrosplenial granular and agranular cortices, subregions of prefrontal cortex, and the olfactory bulb, regions which are directly or indirectly implicated in depression-like behavior. These results may contribute to the understanding of the pathophysiology of major depressive disorder and the role of GalR2 in the regulation of mood, and suggest a potential therapeutic effect by targeting the GalR2 for treatment of depressive disorders.
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Affiliation(s)
- T Wardi Le Maître
- Department of Neuroscience, Karolinska Institutet, Retzius Väg 8, S-17177 Stockholm, Sweden.
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45
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Bhuiyan ME, Waki H, Gouraud SS, Takagishi M, Kohsaka A, Maeda M. Histamine receptor H1 in the nucleus tractus solitarii regulates arterial pressure and heart rate in rats. Am J Physiol Heart Circ Physiol 2011; 301:H523-9. [PMID: 21622829 DOI: 10.1152/ajpheart.00263.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Axons of histamine (HA)-containing neurons are known to project from the posterior hypothalamus to many areas of the brain, including the nucleus tractus solitarii (NTS), a central brain structure that plays an important role in regulating arterial pressure. However, the functional significance of NTS HA is still not fully established. In this study, we microinjected HA or 2-pyridylethylamine, a HA-receptor H(1)-specific agonist, into the NTS of urethane-anesthetized Wister rats to identify the potential functions of NTS HA on cardiovascular regulation. When HA or H(1)-receptor-specific agonist was bilaterally microinjected into the NTS, mean arterial pressure (MAP) and heart rate (HR) were significantly increased, whereas pretreatment with the H(1)-receptor-specific antagonist cetirizine into the NTS significantly inhibited the cardiovascular responses. The maximal responses of MAP and HR changes induced by HA or H(1)-receptor-specific agonist were dose dependent. We also confirmed gene expression of HA receptors in the NTS and that the expression level of H(1) mRNA was higher than that of the other subtypes. In addition, we found that H(1) receptors are mainly expressed in neurons of the NTS. These findings suggested that HA within the NTS may play a role in regulating cardiovascular homeostasis via activation of H(1) receptors expressed in the NTS neurons.
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Affiliation(s)
- Mohammad E Bhuiyan
- Department of Physiology, Wakayama Medical University School of Medicine, Wakayama, Japan
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46
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Stanić D, Mulder J, Watanabe M, Hökfelt T. Characterization of NPY Y2 receptor protein expression in the mouse brain. II. Coexistence with NPY, the Y1 receptor, and other neurotransmitter-related molecules. J Comp Neurol 2011; 519:1219-57. [DOI: 10.1002/cne.22608] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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47
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Smith CM, Shen PJ, Banerjee A, Bonaventure P, Ma S, Bathgate RAD, Sutton SW, Gundlach AL. Distribution of relaxin-3 and RXFP3 within arousal, stress, affective, and cognitive circuits of mouse brain. J Comp Neurol 2010; 518:4016-45. [PMID: 20737598 DOI: 10.1002/cne.22442] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Relaxin-3 (RLN3) and its native receptor, relaxin family peptide 3 receptor (RXFP3), constitute a newly identified neuropeptide system enriched in mammalian brain. The distribution of RLN3/RXFP3 networks in rat brain and recent experimental studies suggest a role for this system in modulation of arousal, stress, metabolism, and cognition. In order to facilitate exploration of the biology of RLN3/RXFP3 in complementary murine models, this study mapped the neuroanatomical distribution of the RLN3/RXFP3 system in mouse brain. Adult, male wildtype and RLN3 knock-out (KO)/LacZ knock-in (KI) mice were used to map the central distribution of RLN3 gene expression and RLN3-like immunoreactivity (-LI). The distribution of RXFP3 mRNA and protein was determined using [(35)S]-oligonucleotide probes and a radiolabeled RXFP3-selective agonist ([(125)I]-R3/I5), respectively. High densities of neurons expressing RLN3 mRNA, RLN3-associated beta-galactosidase activity and RLN3-LI were detected in the nucleus incertus (or nucleus O), while smaller populations of positive neurons were observed in the pontine raphé, the periaqueductal gray and a region adjacent to the lateral substantia nigra. RLN3-LI was observed in nerve fibers/terminals in nucleus incertus and broadly throughout the pons, midbrain, hypothalamus, thalamus, septum, hippocampus, and neocortex, but was absent in RLN3 KO/LacZ KI mice. This RLN3 neural network overlapped the regional distribution of RXFP3 mRNA and [(125)I]-R3/I5 binding sites in wildtype and RLN3 KO/LacZ KI mice. These findings provide further evidence for the conserved nature of RLN3/RXFP3 systems in mammalian brain and the ability of RLN3/RXFP3 signaling to modulate "behavioral state" and an array of circuits involved in arousal, stress responses, affective state, and cognition.
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Affiliation(s)
- Craig M Smith
- Florey Neuroscience Institutes, The University of Melbourne, Victoria 3010, Australia
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48
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Veening JG, de Jong T, Barendregt HP. Oxytocin-messages via the cerebrospinal fluid: behavioral effects; a review. Physiol Behav 2010; 101:193-210. [PMID: 20493198 DOI: 10.1016/j.physbeh.2010.05.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 04/21/2010] [Accepted: 05/04/2010] [Indexed: 12/16/2022]
Abstract
The cerebrospinal fluid (CSF) usually is considered as a protective 'nutrient and waste control' system for the brain. Recent findings suggest, however, that the composition of CSF is actively controlled and may play an influential role in the changes in brain activity, underlying different behavioral states. In the present review, we present an overview of available data concerning the release of oxytocin into the CSF, the location of the oxytocin-receptive brain areas and the behavioral effects of intracerebroventricular oxytocin. About 80% of the oxytocin-receptive areas are located close to the ventricular or subarachnoid CSF, including the hypothalamic 'Behavior Control Column' (L.W.Swanson, 2003). As a conclusion we suggest that 'CSF-oxytocin' contributes considerably to the non-synaptic communication processes involved in hypothalamic-, brainstem- and olfactory brain areas and behavioral states and that the flowing CSF is used as a 'broadcasting system' to send coordinated messages to a wide variety of nearby and distant brain areas.
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Affiliation(s)
- Jan G Veening
- Department of Anatomy (109), UMC St Radboud, Nijmegen, The Netherlands.
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49
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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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50
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Vizi ES, Fekete A, Karoly R, Mike A. Non-synaptic receptors and transporters involved in brain functions and targets of drug treatment. Br J Pharmacol 2010; 160:785-809. [PMID: 20136842 DOI: 10.1111/j.1476-5381.2009.00624.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Beyond direct synaptic communication, neurons are able to talk to each other without making synapses. They are able to send chemical messages by means of diffusion to target cells via the extracellular space, provided that the target neurons are equipped with high-affinity receptors. While synaptic transmission is responsible for the 'what' of brain function, the 'how' of brain function (mood, attention, level of arousal, general excitability, etc.) is mainly controlled non-synaptically using the extracellular space as communication channel. It is principally the 'how' that can be modulated by medicine. In this paper, we discuss different forms of non-synaptic transmission, localized spillover of synaptic transmitters, local presynaptic modulation and tonic influence of ambient transmitter levels on the activity of vast neuronal populations. We consider different aspects of non-synaptic transmission, such as synaptic-extrasynaptic receptor trafficking, neuron-glia communication and retrograde signalling. We review structural and functional aspects of non-synaptic transmission, including (i) anatomical arrangement of non-synaptic release sites, receptors and transporters, (ii) intravesicular, intra- and extracellular concentrations of neurotransmitters, as well as the spatiotemporal pattern of transmitter diffusion. We propose that an effective general strategy for efficient pharmacological intervention could include the identification of specific non-synaptic targets and the subsequent development of selective pharmacological tools to influence them.
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Affiliation(s)
- E S Vizi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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