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Łupina M, Tarnowski M, Baranowska-Bosiacka I, Talarek S, Listos P, Kotlińska J, Gutowska I, Listos J. SB-334867 (an Orexin-1 Receptor Antagonist) Effects on Morphine-Induced Sensitization in Mice-a View on Receptor Mechanisms. Mol Neurobiol 2018; 55:8473-8485. [PMID: 29557083 PMCID: PMC6153720 DOI: 10.1007/s12035-018-0993-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/07/2018] [Indexed: 12/20/2022]
Abstract
The present study focused upon the role of SB-334867, an orexin-1 receptor antagonist, in the acquisition of morphine-induced sensitization to locomotor activity in mice. Behavioral sensitization is an enhanced systemic reaction to the same dose of an addictive substance, which assumingly increases both the desire for the drug and the risk of relapse to addiction. Morphine-induced sensitization in mice was achieved by sporadic doses (five injections every 3 days) of morphine (10 mg/kg, i.p.), while a challenge dose of morphine (10 mg/kg) was injected 7 days later. In order to assess the impact of orexin system blockade on the acquisition of sensitization, SB-334867 was administered before each morphine injection, except the morphine challenge dose. The locomotor activity test was performed on each day of morphine administration. Brain structures (striatum, hippocampus, and prefrontal cortex) were collected after behavioral tests for molecular experiments in which mRNA expression of orexin, dopamine, and adenosine receptors was explored by the qRT-PCR technique. Additionally, the mRNA expression of markers, such as GFAP and Iba-1, was also analyzed by the same technique. SB-334867 inhibited the acquisition of morphine-induced sensitization to locomotor activity of mice. Significant alterations were observed in mRNA expression of orexin, dopamine, and adenosine receptors and in the expression of GFAP and Iba-1, showing a broad range of interactions in the mesolimbic system among orexin, dopamine, adenosine, and glial cells during behavioral sensitization. Summing up, the orexin system may be an effective measure to inhibit morphine-induced behavioral sensitization.
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Affiliation(s)
- Małgorzata Łupina
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4a St., 20-093, Lublin, Poland.
| | - Maciej Tarnowski
- Department of Physiology, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111, Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72 Av., 70-111, Szczecin, Poland
| | - Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4a St., 20-093, Lublin, Poland
| | - Piotr Listos
- Department and Clinic of Animal Internal Diseases, Sub-Department of Pathomorphology and Forensic Medicine, Faculty of Veterinary Medicine, University of Life Sciences in Lublin, 30 Av, 20-612, Lublin, Poland
| | - Jolanta Kotlińska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4a St., 20-093, Lublin, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24 Str., 71-460, Szczecin, Poland
| | - Joanna Listos
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4a St., 20-093, Lublin, Poland
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102
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Bai Q, Pérez-Sánchez H, Shi Z, Li L, Shi D, Liu H, Yao X. Computational studies on horseshoe shape pocket of human orexin receptor type 2 and boat conformation of suvorexant by molecular dynamics simulations. Chem Biol Drug Des 2018; 92:1221-1231. [PMID: 29450984 DOI: 10.1111/cbdd.13181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/08/2017] [Accepted: 11/11/2017] [Indexed: 12/29/2022]
Abstract
The FDA approved drug suvorexant binds to the horseshoe shape pocket of OX2 R with the boat conformation. The horseshoe shape pocket plays an important role on the biological activity of OX2 R in the cell membrane. To study the binding mechanism between the horseshoe shape pocket of OX2 R and boat conformation of suvorexant, the crystal structures of wild type and N324A mutant of OX2 R in complex with antagonist suvorexant are chosen to perform molecular dynamics (MD) simulations, QM/MM, and MMGBSA calculations. By comparison with the wild type of OX2 R, the results show the 1,2,3-triazole and p-toluamide groups of suvorexant are changed in the N324A mutant of OX2 R during 200 ns MD simulations. The QM/MM and weak interaction analysis are employed to calculate the non-covalent bonds interaction between suvorexant and key residues in the wild type and N324A mutant of OX2 R. The MMGBSA calculations indicate the entropy energy is an important influence factor for suvorexant affinity in the distorted horseshoe shape pocket of OX2 R. Our results not only show the horseshoe shape pocket of OX2 R is the necessary conformation for the binding of antagonist suvorexant, but also give the important sites and structural features for antagonist design of OX2 R.
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Affiliation(s)
- Qifeng Bai
- Key Lab of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Horacio Pérez-Sánchez
- Computer Science Department, Universidad Católica San Antonio de Murcia (UCAM), Murcia, Spain
| | - Zhuoyu Shi
- Key Lab of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Lanlan Li
- Department of Chemistry, Lanzhou University, Lanzhou, Gansu, China
| | - Danfeng Shi
- Department of Chemistry, Lanzhou University, Lanzhou, Gansu, China
| | - Huanxiang Liu
- Key Lab of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Xiaojun Yao
- Key Lab of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China.,Department of Chemistry, Lanzhou University, Lanzhou, Gansu, China
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103
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Holland PR. Biology of Neuropeptides: Orexinergic Involvement in Primary Headache Disorders. Headache 2018; 57 Suppl 2:76-88. [PMID: 28485849 DOI: 10.1111/head.13078] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 03/08/2017] [Indexed: 01/01/2023]
Abstract
Migraine is a very common, severe disabling condition that can last for days and strike multiple times per month. Attacks, often characterized by severe unilateral throbbing pain that is exacerbated by activity, are commonly preceded by several diverse symptoms including fatigue, irritability, and yawning. This premonitory (prodromal) phase represents the earliest identifiable feature of an attack that is a reliable predictor of ensuing headache. The diversity of these symptoms underlines the complex nature of migraine and focuses considerable attention on the hypothalamus due to its prominent role in homeostatic regulation allowing state dependent behavioral modifications. While multiple neurotransmitter and neuropeptide systems have been proposed to play a role in migraine, the current review will focus on the emerging role of the hypothalamic orexinergic system in primary headache disorders. Specifically the potential role of altered orexinergic signalling in premonitory symptomatology and the future potential of targeted orexinergic therapies that could with other approaches act during the premonitory phase to prevent the occurrence of the headache or reduce an individual's susceptibility to attacks by altering the brain's response to external and internal triggers.
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Affiliation(s)
- Philip R Holland
- Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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104
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Messina A, Bitetti I, Precenzano F, Iacono D, Messina G, Roccella M, Parisi L, Salerno M, Valenzano A, Maltese A, Salerno M, Sessa F, Albano GD, Marotta R, Villano I, Marsala G, Zammit C, Lavano F, Monda M, Cibelli G, Lavano SM, Gallai B, Toraldo R, Monda V, Carotenuto M. Non-Rapid Eye Movement Sleep Parasomnias and Migraine: A Role of Orexinergic Projections. Front Neurol 2018. [PMID: 29541053 PMCID: PMC5835506 DOI: 10.3389/fneur.2018.00095] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Introduction Sleep and migraine share a common pathophysiological substrate, although the underlying mechanisms are unknown. The serotonergic and orexinergic systems are both involved in the regulation of sleep/wake cycle, and numerous studies show that both are involved in the migraine etiopathogenesis. These two systems are anatomically and functionally interconnected. Our hypothesis is that in migraine a dysfunction of orexinergic projections on the median raphe (MR) nuclei, interfering with serotonergic regulation, may cause Non-Rapid Eye Movement parasomnias, such as somnambulism. Hypothesis/theory Acting on the serotonergic neurons of the raphe nuclei, the dysfunction of orexinergic neurons would lead to a higher release of serotonin. The activation of serotonergic receptors located on the walls of large cerebral vessels would lead to abnormal vasodilatation and consequently increase transmural pressure. This process could activate the trigeminal nerve terminals that innervate vascular walls. As a consequence, there is activation of sensory nerve endings at the level of hard vessels in the meninges, with release of pro-inflammatory peptides (e.g., substance P and CGRP). Within this hypothetical frame, the released serotonin could also interact with trigeminovascular afferents to activate and/or facilitate the release of the neuropeptide at the level of the trigeminal ganglion. The dysregulation of the physiological negative feedback of serotonin on the orexinergic neurons, in turn, would contribute to an alteration of the whole system, altering the sleep–wake cycle. Conclusion Serotonergic neurons of the MR nuclei receive an excitatory input from hypothalamic orexin/hypocretin neurons and reciprocally inhibit orexin/hypocretin neurons through the serotonin 1A receptor (or 5-HT1A receptor). Considering this complex system, if there is an alteration it may facilitate the pathophysiological mechanisms involved in the migraine, while it may produce at the same time an alteration of the sleep–wake rhythm, causing sleep disorders such as sleepwalking. Understanding the complex mechanisms underlying migraine and sleep disorders and how these mechanisms can interact with each other, it would be crucial to pave the way for new therapeutic strategies.
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Affiliation(s)
- Antonietta Messina
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Ilaria Bitetti
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Francesco Precenzano
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Diego Iacono
- Neurodevelopmental Research Lab, Biomedical Research Institute of New Jersey (BRInj), Cedar Knolls NJ, United States.,Neuroscience Research, MidAtlantic Neonatology Associates, Atlantic Health System, Morristown NJ, United States.,Neuropathology Research, MidAtlantic Neonatology Associates (MANA) and Biomedical Research Institute of New Jersey (BRInj), Morristown, NJ, United States
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Michele Roccella
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Lucia Parisi
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Margherita Salerno
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Agata Maltese
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Monica Salerno
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Francesco Sessa
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | | | - Rosa Marotta
- Department of Health Sciences, University "Magna Graecia", Catanzaro, Italy
| | - Ines Villano
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Gabriella Marsala
- Struttura Complessa di Farmacia, Azienda Ospedaliero-Universitaria, Ospedali Riuniti di Foggia, Foggia, Italy
| | - Christian Zammit
- Anatomy Department, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Francesco Lavano
- Department of Health Sciences, University "Magna Graecia", Catanzaro, Italy
| | - Marcellino Monda
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | | | - Beatrice Gallai
- Department of Surgical and Biomedical Sciences, University of Perugia, Perugia, Italy
| | - Roberto Toraldo
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Vincenzo Monda
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Marco Carotenuto
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
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105
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Van de Bittner GC, Van de Bittner KC, Wey HY, Rowe W, Dharanipragada R, Ying X, Hurst W, Giovanni A, Alving K, Gupta A, Hoekman J, Hooker JM. Positron Emission Tomography Assessment of the Intranasal Delivery Route for Orexin A. ACS Chem Neurosci 2018; 9:358-368. [PMID: 29035509 DOI: 10.1021/acschemneuro.7b00357] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Intranasal drug delivery is a noninvasive drug delivery route that can enhance systemic delivery of therapeutics with poor oral bioavailability by exploiting the rich microvasculature within the nasal cavity. The intranasal delivery route has also been targeted as a method for improved brain uptake of neurotherapeutics, with a goal of harnessing putative, direct nose-to-brain pathways. Studies in rodents, nonhuman primates, and humans have pointed to the efficacy of intranasally delivered neurotherapeutics, while radiolabeling studies have analyzed brain uptake following intranasal administration. In the present study, we employed carbon-11 radioactive methylation to assess the pharmacokinetic mechanism of intranasal delivery of Orexin A, a native neuropeptide and prospective antinarcoleptic drug that binds the orexin receptor 1. Using physicochemical and pharmacological analysis, we identified the methylation sites and confirmed the structure and function of methylated Orexin A (CH3-Orexin A) prior to monitoring its brain uptake following intranasal administration in rodent and nonhuman primate. Through positron emission tomography (PET) imaging of [11C]CH3-Orexin A, we determined that the brain exposure to Orexin A is poor after intranasal administration. Additional ex vivo analysis of brain uptake using [125I]Orexin A indicated intranasal administration of Orexin A affords similar brain uptake when compared to intravenous administration across most brain regions, with possible increased brain uptake localized to the olfactory bulbs.
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Affiliation(s)
- Genevieve C. Van de Bittner
- Department
of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Kyle C. Van de Bittner
- Department
of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Hsiao-Ying Wey
- Department
of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Wayne Rowe
- Sanofi US, Bridgewater, New Jersey 08807, United States
| | | | - Xiaoyou Ying
- Sanofi US, Framingham, Massachusetts 01701, United States
| | - William Hurst
- Sanofi US, Bridgewater, New Jersey 08807, United States
| | | | - Kim Alving
- Sanofi US, Waltham, Massachusetts 02451, United States
| | - Anurag Gupta
- Sanofi US, Framingham, Massachusetts 01701, United States
| | - John Hoekman
- Impel NeuroPharma, Seattle, Washington 98119, United States
| | - Jacob M. Hooker
- Department
of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
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106
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Satpute AB, Kragel PA, Barrett LF, Wager TD, Bianciardi M. Deconstructing arousal into wakeful, autonomic and affective varieties. Neurosci Lett 2018; 693:19-28. [PMID: 29378297 DOI: 10.1016/j.neulet.2018.01.042] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 01/13/2018] [Accepted: 01/22/2018] [Indexed: 12/11/2022]
Abstract
Arousal plays a central role in a wide variety of phenomena, including wakefulness, autonomic function, affect and emotion. Despite its importance, it remains unclear as to how the neural mechanisms for arousal are organized across them. In this article, we review neuroscience findings for three of the most common origins of arousal: wakeful arousal, autonomic arousal, and affective arousal. Our review makes two overarching points. First, research conducted primarily in non-human animals underscores the importance of several subcortical nuclei that contribute to various sources of arousal, motivating the need for an integrative framework. Thus, we outline an integrative neural reference space as a key first step in developing a more systematic understanding of central nervous system contributions to arousal. Second, there is a translational gap between research on non-human animals, which emphasizes subcortical nuclei, and research on humans using non-invasive neuroimaging techniques, which focuses more on gross anatomical characterizations of cortical (e.g. network architectures including the default mode network) and subcortical structures. We forecast the importance of high-field neuroimaging in bridging this gap to examine how the various networks within the neural reference space for arousal operate across varieties of arousal-related phenomena.
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Affiliation(s)
- Ajay B Satpute
- Departments of Psychology and Neuroscience, Pomona College, Claremont, CA, USA; Department of Psychology, Northeastern University, Boston, MA, USA.
| | - Philip A Kragel
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, USA; The Institute of Cognitive Science, University of Colorado Boulder, Boulder, USA
| | - Lisa Feldman Barrett
- Department of Psychology, Northeastern University, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA
| | - Tor D Wager
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, USA; The Institute of Cognitive Science, University of Colorado Boulder, Boulder, USA
| | - Marta Bianciardi
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA.
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107
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Suo L, Chang X, Zhao Y. The Orexin-A-Regulated Akt/mTOR Pathway Promotes Cell Proliferation Through Inhibiting Apoptosis in Pancreatic Cancer Cells. Front Endocrinol (Lausanne) 2018; 9:647. [PMID: 30429828 PMCID: PMC6220114 DOI: 10.3389/fendo.2018.00647] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/15/2018] [Indexed: 12/12/2022] Open
Abstract
The orexin-A and its receptors are associated with many physiological processes in peripheral organs and the central nervous system and play important roles in a series of human diseases, including narcolepsy, obesity, and drug addiction. Increasing evidence has indicated high expression of orexin-A and OX1 receptor (OX1R) in malignant tumors, suggesting that the stimulation of OX1R might be essential for tumorigenesis. Here, we attempted to clarify the correlation between orexin-A expression and malignancy in pancreatic cancer. Our results indicated that the stimulation of OX1R promotes cell proliferation in pancreatic cancer PANC1 cells. Additionally, orexin-A treatment can protect PANC1 cells from apoptosis, whereas inhibition of the stimulation of OX1R results in apoptosis through regulating pancreatic cancer cell expression levels of Bcl-2, caspase-9, and c-myc, which are key apoptotic factors. Further investigation revealed that orexin-A treatment activates theAkt/mTOR signaling pathway to promote cell proliferation byinhibiting Bcl-2/caspase-9/c-myc-mediated apoptosis in pancreatic cancer cells. Our findings revealed that the stimulation of OX1R might be important for tumorigenesis in pancreatic cancer and is a potential target for the treatment of patients with pancreatic cancer.
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Affiliation(s)
- Linna Suo
- Department of Endocrinology, The First Affiliated Hospital, China Medical University, Shenyang, China
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital, China Medical University, Shenyang, China
| | - Xiaocen Chang
- Department of Endocrinology, The First Affiliated Hospital, China Medical University, Shenyang, China
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital, China Medical University, Shenyang, China
| | - Yuyan Zhao
- Department of Endocrinology, The First Affiliated Hospital, China Medical University, Shenyang, China
- *Correspondence: Yuyan Zhao
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108
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Crystal Structures of Human Orexin 2 Receptor Bound to the Subtype-Selective Antagonist EMPA. Structure 2018; 26:7-19.e5. [DOI: 10.1016/j.str.2017.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/02/2017] [Accepted: 11/08/2017] [Indexed: 11/16/2022]
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109
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Abstract
Despite decades of intense study, the functions of sleep are still shrouded in mystery. The difficulty in understanding these functions can be at least partly attributed to the varied manifestations of sleep in different animals. Daily sleep duration can range from 4-20 hrs among mammals, and sleep can manifest throughout the brain, or it can alternate over time between cerebral hemispheres, depending on the species. Ecological factors are likely to have shaped these and other sleep behaviors during evolution by altering the properties of conserved arousal circuits in the brain. Nonetheless, core functions of sleep are likely to have arisen early and to have persisted to the present day in diverse organisms. This review will discuss the evolutionary forces that may be responsible for phylogenetic differences in sleep and the potential core functions that sleep fulfills.
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Affiliation(s)
- William J Joiner
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093-0636, USA; Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093-0636, USA; Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093-0636, USA; Center for Circadian Biology, University of California San Diego, La Jolla, CA 92093-0636, USA.
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110
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Sheng Q, Xue Y, Wang Y, Chen AQ, Liu C, Liu YH, Chu HY, Chen L. The Subthalamic Neurons are Activated by Both Orexin-A and Orexin-B. Neuroscience 2017; 369:97-108. [PMID: 29138106 DOI: 10.1016/j.neuroscience.2017.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/02/2017] [Accepted: 11/04/2017] [Indexed: 02/02/2023]
Abstract
The subthalamic nucleus is an important nucleus in the indirect pathway of the basal ganglia circuit and therefore is involved in motor control under both normal and pathological conditions. Morphological studies reveal that the subthalamic nucleus receives relatively dense orexinergic projections originating from the hypothalamus. Both orexin-1 (OX1) and orexin-2 (OX2) receptors are expressed in the subthalamic nucleus. To explore the functions of orexinergic system in the subthalamic nucleus, extracellular electrophysiological recordings and behavioral tests were performed in the present study. Exogenous application of orexin-A significantly increased the spontaneous firing rate from 5.70 ± 0.66 Hz to 9.87 ± 1.18 Hz in 64.00% subthalamic neurons recorded. OX1 receptors are involved in orexin-A-induced excitation. Application of orexin-B increased the firing rate from 7.47 ± 0.92 Hz to 11.85 ± 1.39 Hz in 80.95% subthalamic neurons recorded, entirely through OX2 receptors. Both OX1 and OX2 receptor antagonists decreased the firing rate in 43.75% and 62.50% subthalamic neurons recorded respectively, suggesting the involvement of endogenous orexinergic system in the control of spontaneous firing activity. Further elevated body swing test revealed that microinjection of orexins and the receptor antagonists into the subthalamic nucleus induced contralateral-biased swing and ipsilateral-biased swing, respectively. Taken together, the present study suggests that orexins play important roles in the subthalamic nucleus which may provide further evidence for the involvement of subthalamic orexinergic tone in Parkinson's disease. SIGNIFICANCE Previous morphological studies indicate that the subthalamic nucleus receives orexinergic innervation and expresses both OX1 and OX2 receptors. Using in vivo multibarrel electrophysiological recordings, the present study revealed that exogenous application of orexin-A and orexin-B increased the spontaneous firing rate of the subthalamic neurons through OX1 and OX2 receptors. Endogenous orexinergic system was involved in the control of spontaneous firing of the subthalamic neurons. Further behavioral test revealed that intrasubthalamic application of orexins and the receptor antagonists induced biased swing behavior. The present study may provide further evidence for the involvement of subthalamic orexinergic tone in Parkinson's disease.
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Affiliation(s)
- Qing Sheng
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - Yan Xue
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - Ying Wang
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - An-Qi Chen
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - Cui Liu
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - Yun-Hai Liu
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - Hong-Yan Chu
- Department of Physiology, Qingdao University, Qingdao 266071, China
| | - Lei Chen
- Department of Physiology, Qingdao University, Qingdao 266071, China.
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111
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Futamura A, Nozawa D, Araki Y, Tamura Y, Tokura S, Kawamoto H, Tokumaru Y, Kakihara S, Aoki T, Ohtake N. Identification of highly selective and potent orexin receptor 1 antagonists derived from a dual orexin receptor 1/2 antagonist based on the structural framework of pyrazoylethylbenzamide. Bioorg Med Chem 2017; 25:5203-5215. [DOI: 10.1016/j.bmc.2017.07.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/15/2017] [Accepted: 07/18/2017] [Indexed: 11/28/2022]
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112
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Haghparast A, Fatahi Z, Arezoomandan R, Karimi S, Taslimi Z, Zarrabian S. Functional roles of orexin/hypocretin receptors in reward circuit. PROGRESS IN BRAIN RESEARCH 2017; 235:139-154. [PMID: 29054286 DOI: 10.1016/bs.pbr.2017.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Since its first discovery in 1998, it has become clear that the orexinergic system plays an important role in regulating a number of functions including food, sex, social connections, and most prominently reward-related behaviors. Orexinergic neurons in the lateral hypothalamus project extensively to other brain areas, two most important of which are the ventral tegmental area and the nucleus accumbens that are involved in reward processing. In this review, we have presented the work in our laboratory along with the work of others and have discussed the possible functions we can infer from the research. We discuss the anatomy of the orexinergic system and its components followed by a presentation of other connected brain areas. The second part of this review discusses observed results from the morphine conditioned place preference test that sheds light on the possible role of the involved areas in reward processing. The complex circuits involved in reward processing are only beginning to be understood and we need to deepen our understanding regarding the nature of the interactions between all brain areas involved.
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Affiliation(s)
- Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Zahra Fatahi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Arezoomandan
- School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran
| | - Sara Karimi
- Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | - Zahra Taslimi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Shahram Zarrabian
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
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113
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Wan X, Liu Y, Zhao Y, Sun X, Fan D, Guo L. Orexin A affects HepG2 human hepatocellular carcinoma cells glucose metabolism via HIF-1α-dependent and -independent mechanism. PLoS One 2017; 12:e0184213. [PMID: 28886081 PMCID: PMC5590901 DOI: 10.1371/journal.pone.0184213] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 08/21/2017] [Indexed: 01/20/2023] Open
Abstract
Orexins are hypothalamic neuropeptides that regulate feeding, reward, wakefulness and energy homeostasis. The present study sought to characterize the involvement of orexin A in glucose metabolism in HepG2 human hepatocellular carcinoma cells, and investigated the role of hypoxia-inducible factor-1α (HIF-1α) in the response. HepG2 cells were exposed to different concentrations of orexin A (10−9 to 10−7 M) in vitro, without or with the orexin receptor 1 (OX1R) inhibitor (SB334867), HIF-1α inhibitor (YC-1) or a combination of both inhibitors. Subsequently, OX1R, HIF-1α expression and localization, glucose uptake, glucose transporter 1 (GLUT1) expression and ATP content were measured. We further investigated the intracellular fate of glucose by measuring the gene expression of pyruvate dehydrogenase kinase 1 (PDK1), lactate dehydrogenase (LDHA) and pyruvate dehydrogenase B (PDHB), as well as metabolite levels including lactate generation and mitochondrial pyruvate dehydrogenase (PDH) activity. The activity of phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway was also assessed. Our results showed that the expression of OX1R was predominantly located in the nucleus in HepG2 cells. Orexin A oxygen-independently promoted the mRNA and protein expression of HIF-1α as well as its nuclear accumulation in HepG2 cells and the elevated HIF-1α protein was associated, at least partly, with the activation of the PI3K/Akt/mTOR pathway. Orexin A stimulated GLUT1 expression, glucose uptake as well as ATP generation in HepG2 cells via OX1R acting through the HIF-1α pathway. Moreover, orexin A inhibited LDHA, PDK1 expression and lactate production, stimulated PDHB expression and PDH enzyme activity independent of HIF-1α. Our results indicated that orexin signaling facilitated the glucose flux into mitochondrial oxidative metabolism rather than glycolysis in HepG2 cells. These findings provide new insight into the regulation of glucose metabolism by orexin A in hepatocellular carcinoma cells.
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Affiliation(s)
- Xing Wan
- Department of Medical Oncology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, P.R. China
| | - Yuanyuan Liu
- Department of Endocrinology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, P.R. China
| | - Yuyan Zhao
- Department of Endocrinology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, P.R. China
- * E-mail: (LG); (YZ)
| | - Xiaoqi Sun
- Department of Endocrinology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, P.R. China
| | - Dongxiao Fan
- Department of Orthopedic Surgery, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, P.R. China
| | - Lei Guo
- Department of Orthopedic Surgery, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, P.R. China
- * E-mail: (LG); (YZ)
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114
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de Biase S, Nilo A, Gigli GL, Valente M. Investigational therapies for the treatment of narcolepsy. Expert Opin Investig Drugs 2017; 26:953-963. [PMID: 28726523 DOI: 10.1080/13543784.2017.1356819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Narcolepsy is a chronic sleep disorder characterized by a pentad of excessive daytime sleepiness (EDS), cataplexy, sleep paralysis, hypnagogic/hypnopompic hallucinations, and disturbed nocturnal sleep. While non-pharmacological treatments are sometimes helpful, more than 90% of narcoleptic patients require a pharmacological treatment. Areas covered: The present review is based on an extensive Internet and PubMed search from 1994 to 2017. It is focused on drugs currently in development for the treatment of narcolepsy. Expert opinion: Currently there is no cure for narcolepsy, with treatment focusing on symptoms control. However, these symptomatic treatments are often unsatisfactory. The research is leading to a better understanding of narcolepsy and its symptoms. New classes of compounds with possible applications in the development of novel stimulant/anticataplectic medications are described. H3 receptor antagonists represent a new therapeutic option for EDS in narcolepsy. JZP-110, with its distinct mechanism of action, would be a new therapeutic option for the treatment of EDS in the coming years. In the future, hypocretin-based therapies and immune-based therapies, could modify the clinical course of the disease. However, more information would be necessary to completely understand the autoimmune process and also how this process can be altered for therapeutic benefits.
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Affiliation(s)
- Stefano de Biase
- a Neurology Unit, Department of Experimental and Clinical Medical Sciences , University of Udine Medical School , Udine , Italy
| | - Annacarmen Nilo
- a Neurology Unit, Department of Experimental and Clinical Medical Sciences , University of Udine Medical School , Udine , Italy
| | - Gian Luigi Gigli
- a Neurology Unit, Department of Experimental and Clinical Medical Sciences , University of Udine Medical School , Udine , Italy.,b Department of Neurosciences , "S. Maria della Misericordia" University Hospital Udine , Udine , Italy
| | - Mariarosaria Valente
- a Neurology Unit, Department of Experimental and Clinical Medical Sciences , University of Udine Medical School , Udine , Italy.,b Department of Neurosciences , "S. Maria della Misericordia" University Hospital Udine , Udine , Italy
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115
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Yun S, Wennerholm M, Shelton JE, Bonaventure P, Letavic MA, Shireman BT, Lovenberg TW, Dugovic C. Selective Inhibition of Orexin-2 Receptors Prevents Stress-Induced ACTH Release in Mice. Front Behav Neurosci 2017; 11:83. [PMID: 28533747 PMCID: PMC5420581 DOI: 10.3389/fnbeh.2017.00083] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/19/2017] [Indexed: 11/13/2022] Open
Abstract
Orexins peptides exert a prominent role in arousal-related processes including stress responding, by activating orexin-1 (OX1R) and orexin-2 (OX2R) receptors located widely throughout the brain. Stress or orexin administration stimulates hyperarousal, adrenocorticotropic hormone (ACTH) and corticosterone release, and selective OX1R blockade can attenuate several stress-induced behavioral and cardiovascular responses but not the hypothalamic-pituitary-adrenal (HPA) axis activation. As opposed to OX1R, OX2R are preferentially expressed in the paraventricular hypothalamic nucleus which is involved in the HPA axis regulation. In the present study, we investigated the effects of a psychological stress elicited by cage exchange (CE) on ACTH release in two murine models (genetic and pharmacological) of selective OX2R inhibition. CE-induced stress produced a significant increase in ACTH serum levels. Mice lacking the OX2R exhibited a blunted stress response. Stress-induced ACTH release was absent in mice pre-treated with the selective OX2R antagonist JNJ-42847922 (30 mg/kg po), whereas pre-treatment with the dual OX1/2R antagonist SB-649868 (30 mg/kg po) only partially attenuated the increase of ACTH. To assess whether the intrinsic and distinct sleep-promoting properties of each antagonist could account for the differential stress response, a separate group of mice implanted with electrodes for standard sleep recording were orally dosed with JNJ-42847922 or SB-649868 during the light phase. While both compounds reduced the latency to non-rapid eye movement (NREM) sleep without affecting its duration, a prevalent REM-sleep promoting effect was observed only in mice treated with the dual OX1/2R antagonist. These data indicate that in a psychological stress model, genetic or pharmacological inhibition of OX2R markedly attenuated stress-induced ACTH secretion, as a separately mediated effect from the NREM sleep induction of OX2R antagonism.
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Affiliation(s)
- Sujin Yun
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Michelle Wennerholm
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Jonathan E Shelton
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Pascal Bonaventure
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Michael A Letavic
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Brock T Shireman
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Timothy W Lovenberg
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
| | - Christine Dugovic
- Department of Neuroscience, Janssen Research and Development, L.L.C.San Diego, CA, USA
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116
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Flores Á, Herry C, Maldonado R, Berrendero F. Facilitation of Contextual Fear Extinction by Orexin-1 Receptor Antagonism Is Associated with the Activation of Specific Amygdala Cell Subpopulations. Int J Neuropsychopharmacol 2017; 20:654-659. [PMID: 28453642 PMCID: PMC5570099 DOI: 10.1093/ijnp/pyx029] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Orexins are hypothalamic neuropeptides recently involved in the regulation of emotional memory. The basolateral amygdala, an area orchestrating fear memory processes, appears to be modulated by orexin transmission during fear extinction. However, the neuronal types within the basolateral amygdala involved in this modulation remain to be elucidated. METHODS We used retrograde tracing combined with immunofluorescence techniques in mice to identify basolateral amygdala projection neurons and cell subpopulations in this brain region influenced by orexin transmission during contextual fear extinction consolidation. RESULTS Treatment with the orexin-1 receptor antagonist SB334867 increased the activity of basolateral amygdala neurons projecting to infralimbic medial prefrontal cortex during fear extinction. GABAergic interneurons expressing calbindin, but not parvalbumin, were also activated by orexin-1 receptor antagonism in the basolateral amygdala. CONCLUSIONS These data identify neuronal circuits and cell populations of the amygdala associated with the facilitation of fear extinction consolidation induced by the orexin-1 receptor antagonist SB334867.
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Affiliation(s)
- África Flores
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain (Drs Flores, Maldonado, and Berrendero); INSERM, Neurocentre Magendie, Bordeaux, France (Dr Herry); University Bordeaux, Neurocentre Magendie, Bordeaux, France (Dr Herry); Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Madrid, Spain (Dr Berrendero)
| | - Cyril Herry
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain (Drs Flores, Maldonado, and Berrendero); INSERM, Neurocentre Magendie, Bordeaux, France (Dr Herry); University Bordeaux, Neurocentre Magendie, Bordeaux, France (Dr Herry); Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Madrid, Spain (Dr Berrendero)
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain (Drs Flores, Maldonado, and Berrendero); INSERM, Neurocentre Magendie, Bordeaux, France (Dr Herry); University Bordeaux, Neurocentre Magendie, Bordeaux, France (Dr Herry); Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Madrid, Spain (Dr Berrendero)
| | - Fernando Berrendero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain (Drs Flores, Maldonado, and Berrendero); INSERM, Neurocentre Magendie, Bordeaux, France (Dr Herry); University Bordeaux, Neurocentre Magendie, Bordeaux, France (Dr Herry); Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Madrid, Spain (Dr Berrendero)
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117
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Kristiansen ES, Nielsen LS, Christensen SS, Botvid SHC, Nørgaard Poulsen J, Gazerani P. Sleep deprivation sensitizes human craniofacial muscles. Somatosens Mot Res 2017; 34:116-122. [DOI: 10.1080/08990220.2017.1317241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Louise Skou Nielsen
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | | | | | | | - Parisa Gazerani
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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118
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Coborn JE, DePorter DP, Mavanji V, Sinton CM, Kotz CM, Billington CJ, Teske JA. Role of orexin-A in the ventrolateral preoptic area on components of total energy expenditure. Int J Obes (Lond) 2017; 41:1256-1262. [PMID: 28392556 DOI: 10.1038/ijo.2017.92] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 03/20/2017] [Accepted: 03/26/2017] [Indexed: 12/23/2022]
Abstract
BACKGROUND Identifying whether components of total energy expenditure (EE) are affected by orexin receptor (OXR1 and OXR2) stimulation or antagonism with dual orexin receptor antagonists (DORAs) has relevance for obesity treatment. Orexin receptor stimulation reduces weight gain by increasing total EE and EE during spontaneous physical activity (SPA). OBJECTIVE The purpose of this study was to determine if a DORA (TCS-1102) in the ventrolateral preoptic area (VLPO) reduced orexin-A-induced arousal, SPA, total EE and EE during sleep, rest, wake and SPA and whether the DORA alone reduced total EE and its components. We hypothesized that: (1) a DORA would reduce orexin-A induced increases in arousal, SPA, components of total EE, reductions in sleep and the EE during sleep and (2) the DORA alone would reduce baseline (non-stimulated) SPA and total EE. SUBJECTS/METHODS Sleep, wakefulness, SPA and EE were determined after microinjection of the DORA (TCS-1102) and orexin-A in the VLPO of male Sprague-Dawley rats with a unilateral cannula targeted towards the VLPO. Individual components of total EE were determined based on time-stamped data. RESULTS The DORA reduced orexin-A-induced increases in arousal, SPA, total EE and EE during SPA, wake, rest and sleep 1 h post injection (P<0.05). Orexin-A significantly reduced sleep and significantly increased EE during sleep 1 h post injection (P<0.05). Furthermore, the DORA alone significantly reduced total EE, EE during sleep (NREM and REM) and resting EE 2 h post injection (P<0.05). CONCLUSIONS These data suggest that orexin-A reduces weight gain by stimulating total EE through increases in EE during SPA, rest and sleep. Residual effects of the DORA alone include decreases in total EE and EE during sleep and rest, which may promote weight gain.
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Affiliation(s)
- J E Coborn
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA
| | - D P DePorter
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA
| | - V Mavanji
- Minneapolis VA Health Care System, Minneapolis, MN, USA
| | - C M Sinton
- Arizona Respiratory Center, University of Arizona, Tucson, AZ, USA
| | - C M Kotz
- Minneapolis VA Health Care System, Minneapolis, MN, USA.,Geriatric Research Education and Clinical Center, Minneapolis, MN, USA.,Minnesota Obesity Center, Saint Paul, MN, USA.,Department of Food Science and Nutrition, University of Minnesota, Saint Paul, MN, USA
| | - C J Billington
- Minneapolis VA Health Care System, Minneapolis, MN, USA.,Minnesota Obesity Center, Saint Paul, MN, USA.,Department of Food Science and Nutrition, University of Minnesota, Saint Paul, MN, USA.,Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - J A Teske
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA.,Minneapolis VA Health Care System, Minneapolis, MN, USA.,Minnesota Obesity Center, Saint Paul, MN, USA.,Department of Food Science and Nutrition, University of Minnesota, Saint Paul, MN, USA
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119
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Pitts PM, Volkoff H. Characterization of appetite-regulating factors in platyfish, Xiphophorus maculatus (Cyprinodontiformes Poeciliidae). Comp Biochem Physiol A Mol Integr Physiol 2017; 208:80-88. [PMID: 28377124 DOI: 10.1016/j.cbpa.2017.03.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 10/19/2022]
Abstract
The regulation of energy in fish, like most vertebrates, is a complex process that involves a number of brain and peripheral hormones. These signals include anorexigenic (e.g. cholecystokinin (CCK) and cocaine- and amphetamine-regulated transcript (CART)) as well as orexigenic (e.g. orexin and neuropeptide Y (NPY)) peptides. Platyfish, Xiphophorus maculatus, are freshwater viviparous fish for which little is known about the endocrine mechanisms regulating feeding. In order to elucidate the role of these peptides in the regulation of feeding of platyfish, we examined the effects of peripheral injections of CCK and orexin on feeding behavior and food intake. Injections of CCK decreased both food intake and searching behavior, while injections of orexin increased searching behavior but did not affect food consumption. In order to better characterize these peptides, we examined their mRNA tissue distribution and assessed the effects of a 10-day fast on their brain and intestine expressions in both males and females. CCK, CART, NPY and orexin all show widespread distributions in brain and several peripheral tissues, including intestine and gonads. Fasting induced decreases in both CCK and CART and an increase in orexin mRNA expressions in the brain and a decrease in CCK expression in the intestine, but did not affect either expressions of NPY. There were no significant sex-specific differences in either the behavioral responses to injections or the expression responses to fasting. The widespread distribution and the fasting-induced changes in expression of these peptides suggest that they might have several physiological roles in platyfish, including the regulation of feeding.
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Affiliation(s)
- Paul M Pitts
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada
| | - Hélène Volkoff
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada; Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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120
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Pasban-Aliabadi H, Esmaeili-Mahani S, Abbasnejad M. Orexin-A Protects Human Neuroblastoma SH-SY5Y Cells Against 6-Hydroxydopamine-Induced Neurotoxicity: Involvement of PKC and PI3K Signaling Pathways. Rejuvenation Res 2017; 20:125-133. [PMID: 27814668 DOI: 10.1089/rej.2016.1836] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder that is characterized by progressive and selective death of dopaminergic neurons. Multifunctional neuropeptide orexin-A is involved in many biological events of the body. It has been shown that orexin-A has protective effects in neurodegenerative disease such as PD. However, its cellular mechanisms have not yet been fully clarified. Here, we investigated the intracellular signaling pathway of orexin-A neuroprotection in 6-hydroxydopamine (6-OHDA)-induced SH-SY5H cells damage as an in vitro model of PD. The cells were incubated with 150 μM 6-OHDA, and the viability was examined by 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2-tetrazolium bromide (MTT) assay. Mitochondrial membrane potential and intracellular calcium were measured by fluorescent probes. Western blotting was also used to determine cyclooxygenase type 2 (COX-2), nuclear factor erythroid 2 related factor 2 (Nrf2), and HSP70 protein levels. The data showed that 6-OHDA has decreasing effects on cell viability, Nrf2, and HSP70 protein expression and increases the level of mitochondrial membrane potential, intracellular calcium, and COX-2 protein. Orexin-A (500 pM) significantly attenuated the 6-OHDA-induced cell damage. Furthermore, Orexin-A significantly prevented the mentioned effects of 6-OHDA on SH-SY5Y cells. Orexin 1 receptor antagonist (SB3344867), PKC, and PI3-kinase (PI3K) inhibitors (chelerythrin and LY294002, respectively) could suppress the orexin-A neuroprotective effect. In contrast, blockage of PKA by a selective inhibitor (KT5720) had no effects on the orexin protection. The results suggest that orexin-A protective effects against 6-OHDA-induced neurotoxicity are performed via its receptors, PKC and PI3K signaling pathways.
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Affiliation(s)
- Hamzeh Pasban-Aliabadi
- 1 Department of Biology, Faculty of Sciences, ShahidBahonar University of Kerman , Kerman, Iran
| | - Saeed Esmaeili-Mahani
- 1 Department of Biology, Faculty of Sciences, ShahidBahonar University of Kerman , Kerman, Iran .,2 Laboratory of Molecular Neuroscience, Kerman Neuroscience Research Center (KNRC), Kerman University of Medical Sciences , Kerman, Iran
| | - Mehdi Abbasnejad
- 1 Department of Biology, Faculty of Sciences, ShahidBahonar University of Kerman , Kerman, Iran
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121
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Hagar JM, Macht VA, Wilson SP, Fadel JR. Upregulation of orexin/hypocretin expression in aged rats: Effects on feeding latency and neurotransmission in the insular cortex. Neuroscience 2017; 350:124-132. [PMID: 28344067 DOI: 10.1016/j.neuroscience.2017.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
Abstract
Aging is associated with changes in numerous homeostatic functions, such as food intake, that are thought to be mediated by the hypothalamus. Orexin/hypocretin neurons of the hypothalamus regulate several physiological functions, including feeding, sleep and wakefulness. Evidence from both clinical and animal studies supports the notion that aging is associated with loss or dysregulation of the orexin system. Here, we used virus-mediated gene transfer to manipulate expression of orexin peptides in young and aged rats and examined behavioral and neurochemical correlates of food intake in these animals. Aged rats showed slower feeding latencies when presented with palatable food compared to young control rats, and these deficits were ameliorated by upregulation of orexin expression. Similarly, young animals treated with a virus designed to decrease preproorexin expression showed longer feeding latencies reminiscent of aged control rats. Feeding was also associated with increased acetylcholine, glutamate and GABA efflux in insular cortex of young control animals. Orexin upregulation did not restore deficits in feeding-elicited release of these neurotransmitters in aged rats, but did enhance basal neurotransmitter levels which may have contributed to the behavioral correlates of these genetic manipulations. These studies demonstrate that age-related deficits in behavioral and neurochemical measures of feeding are likely to be mediated, in part, by the orexin system. Because these same neurotransmitter systems have been shown to underlie orexin effects on cognition, treatments which increase orexin function may have potential for improving both physiological and cognitive manifestations of certain age-related disorders.
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Affiliation(s)
- Janel M Hagar
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA
| | - Victoria A Macht
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA; Department of Psychology, University of South Carolina School of Medicine, Columbia, SC 29208, USA
| | - Steven P Wilson
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA
| | - James R Fadel
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
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122
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Tafuri S, De Pasquale V, Costagliola A, Della Morte R, Avallone L, Pavone LM. Health and disease, an orchestra of three players: Serotonin, orexins, and nitric oxide. J Neurosci Res 2017; 95:1891-1893. [DOI: 10.1002/jnr.24030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/04/2017] [Accepted: 01/04/2017] [Indexed: 01/16/2023]
Affiliation(s)
- Simona Tafuri
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Naples Italy
| | - Valeria De Pasquale
- Department of Molecular Medicine and Medical Biotechnology; University of Naples Federico II; Naples Italy
| | - Anna Costagliola
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Naples Italy
| | - Rossella Della Morte
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Naples Italy
| | - Luigi Avallone
- Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; Naples Italy
| | - Luigi Michele Pavone
- Department of Molecular Medicine and Medical Biotechnology; University of Naples Federico II; Naples Italy
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123
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Abstract
Narcolepsy is a chronic sleep disorder that has a typical onset in adolescence and is characterized by excessive daytime sleepiness, which can have severe consequences for the patient. Problems faced by patients with narcolepsy include social stigma associated with this disease, difficulties in obtaining an education and keeping a job, a reduced quality of life and socioeconomic consequences. Two subtypes of narcolepsy have been described (narcolepsy type 1 and narcolepsy type 2), both of which have similar clinical profiles, except for the presence of cataplexy, which occurs only in patients with narcolepsy type 1. The pathogenesis of narcolepsy type 1 is hypothesized to be the autoimmune destruction of the hypocretin-producing neurons in the hypothalamus; this hypothesis is supported by immune-related genetic and environmental factors associated with the disease. However, direct evidence in support of the autoimmune hypothesis is currently unavailable. Diagnosis of narcolepsy encompasses clinical, electrophysiological and biological evaluations, but simpler and faster procedures are needed. Several medications are available for the symptomatic treatment of narcolepsy, all of which have quite good efficacy and safety profiles. However, to date, no treatment hinders or slows disease development. Improved diagnostic tools and increased understanding of the pathogenesis of narcolepsy type 1 are needed and might lead to therapeutic or even preventative interventions.
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Affiliation(s)
- Birgitte R Kornum
- Molecular Sleep Laboratory, Department of Clinical Biochemistry, Rigshospitalet, Forskerparken, Nordre Ringvej 69, 2600 Glostrup, Denmark.,Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Stine Knudsen
- Norwegian Centre of Expertise for Neurodevelopmental Disorders and Hypersomnias, Oslo University Hospital, Oslo, Norway
| | - Hanna M Ollila
- Department of Psychiatry and Behavioral Sciences, Center for Sleep Sciences, Stanford University, Stanford, California, USA
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, AUSL di Bologna, Bologna, Italy
| | - Poul J Jennum
- Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Yves Dauvilliers
- Sleep Unit, Narcolepsy Reference Center, Department of Neurology, Gui de Chauliac Hospital, INSERM 1061, Montpellier, France
| | - Sebastiaan Overeem
- Sleep Medicine Center Kempenhaeghe, Heeze, The Netherlands.,Department of Industrial Design, Eindhoven University of Technology, Eindhoven, The Netherlands
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Liguori G, Pavone LM, Assisi L, Langella E, Tafuri S, Mirabella N, Costagliola A, Vittoria A. Expression of orexin B and its receptor 2 in rat testis. Gen Comp Endocrinol 2017; 242:66-73. [PMID: 26631456 DOI: 10.1016/j.ygcen.2015.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 11/18/2022]
Abstract
The peptides orexin A (OxA) and orexin B (OxB) deriving from a common precursor molecule, prepro-orexin, by proteolytic cleavage, bind the two G-coupled OX1 and OX2 receptors. While OX1 selectively binds OxA, OX2 shows similar affinity for both orexins. Firstly discovered in the hypothalamus, orexins and their receptors have been found in other brain regions as well as in peripheral tissues of mammals, thus resulting involved in the regulation of a broad variety of physiological functions. While the functional localization of OxA and OX1 in the mammalian genital tract has been already described, the expression of OxB and OX2 and their potential role in the reproductive functions remain to be explored. Here, we investigated the presence of OxB and OX2 in the rat testis by immunohistochemical and biochemical analyses. The results definitely demonstrated the localization of OxB and OX2 in pachytene and second spermatocytes as well as in spermatids at all stages of the cycle of the seminiferous epithelium. The expression of both OX2 mRNA and protein in the rat testis was also established by RT-PCR and Western blotting, respectively. The analysis of the molecular mechanism of action of OxB in the rat testis showed that OxB, in contrast with OxA, is unable to promote steroidogenesis. These results translate into the regulation of diverse biological actions by OxA and OxB in the male gonad.
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Affiliation(s)
- Giovanna Liguori
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy
| | - Luigi Michele Pavone
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, 80131 Naples, Italy
| | - Loredana Assisi
- Department of Biology, University of Naples Federico II, Via Mezzocannone 6, 80134 Naples, Italy
| | - Emilia Langella
- School of Agricultural, Forestry, Food and Environmental Sciences, University of Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Simona Tafuri
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy
| | - Nicola Mirabella
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy
| | - Anna Costagliola
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy
| | - Alfredo Vittoria
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy.
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125
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Gong Y, Liu Y, Liu F, Wang S, Jin H, Guo F, Xu L. Ghrelin fibers from lateral hypothalamus project to nucleus tractus solitaries and are involved in gastric motility regulation in cisplatin-treated rats. Brain Res 2017; 1659:29-40. [PMID: 28093190 DOI: 10.1016/j.brainres.2017.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 12/28/2016] [Accepted: 01/01/2017] [Indexed: 12/16/2022]
Abstract
Ghrelin can alleviate cancer chemotherapy-induced dyspepsia in rodents, though the neural mechanisms involved are not known. Therefore, ghrelin projections from the lateral hypothalamus (LH) and its involvement in the regulation of gastric motility in cisplatin-treated rats were investigated with a multi-disciplined approach. Retrograde tracing combined with fluoro-immunohistochemical staining were used to investigate ghrelin fiber projections arising from LH and projecting to nucleus tractus solitaries (NTS). Results revealed that ghrelin fibers originating in LH project to NTS. Expression of ghrelin and its receptor growth hormone secretagogue receptor (GHS-R1a) in LH and NTS were detected by Western Blot. 2days after cisplatin dosing, expression of ghrelin in LH decreased while GHS-R1a in both LH and NTS increased. In electrophysiological experiments, the effects of N-methyl-d-aspartate (NMDA) microinjection in LH on neuronal discharge of gastric distension-responsive neurons in NTS and gastric motility were assessed. NMDA in LH excited most of ghrelin-responsive gastric distension (GD)-sensitive neurons in NTS and promoted gastric motility. This effect was partially blocked by ghrelin antibody in NTS. Furthermore, the excitatory effects of NMDA in cisplatin-treated rats were weaker than those in saline-treated rats. Behaviorally, cisplatin induced a significant increase of kaolin consumption and decrease of food intake. These studies reveal a decreased expression of ghrelin in LH and up-regulation of GHS-R1a in LH and NTS, which are involved in the regulation of GD neuronal discharge in NTS and gastric motility.
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Affiliation(s)
- Yanling Gong
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, China.
| | - Yang Liu
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, China
| | - Fei Liu
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, China
| | - Shasha Wang
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, China
| | - Hong Jin
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, China
| | - Feifei Guo
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong, China
| | - Luo Xu
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong, China.
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Abstract
The human orexin/hypocretin receptors (hOX1R and hOX2R) are G protein-coupled receptors (GPCRs) that mediate the diverse functions of the orexin/hypocretin neuropeptides. Orexins/hypocretins produced by neurons in the lateral hypothalamus stimulate their cognate GPCRs in multiple regions of the central nervous system to control sleep and arousal, circadian rhythms, metabolism, reward pathways, and other behaviors. Dysfunction of orexin/hypocretin signaling is associated with human disease, and the receptors are active targets in a number of therapeutic areas. To better understand the molecular mechanism of the orexin/hypocretin neuropeptides, high-resolution three-dimensional structures of hOX1R and hOX2R are critical. We have solved high-resolution crystal structures of both human orexin/hypocretin receptors bound to high-affinity antagonists. These atomic structures have elucidated how different small molecule antagonists bind with high potency and selectivity, and have also provided clues as to how the native ligands may associate with their receptors. The orexin/hypocretin receptor coordinates, now available to the broader academic and drug discovery community, will facilitate rational design of new therapeutics that modulate orexin/hypocretin signaling in humans.
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Affiliation(s)
- Jie Yin
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Daniel M Rosenbaum
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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James MH, Mahler SV, Moorman DE, Aston-Jones G. A Decade of Orexin/Hypocretin and Addiction: Where Are We Now? Curr Top Behav Neurosci 2017; 33:247-281. [PMID: 28012090 PMCID: PMC5799809 DOI: 10.1007/7854_2016_57] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
One decade ago, our laboratory provided the first direct evidence linking orexin/hypocretin signaling with drug seeking by showing that activation of these neurons promotes conditioned morphine-seeking behavior. In the years since, contributions from many investigators have revealed roles for orexins in addiction for all drugs of abuse tested, but only under select circumstances. We recently proposed that orexins play a fundamentally unified role in coordinating "motivational activation" under numerous behavioral conditions, and here we unpack this hypothesis as it applies to drug addiction. We describe evidence collected over the past 10 years that elaborates the role of orexin in drug seeking under circumstances where high levels of effort are required to obtain the drug, or when motivation for drug reward is augmented by the presence of external stimuli like drug-associated cues/contexts or stressors. Evidence from studies using traditional self-administration and reinstatement models, as well as behavioral economic analyses of drug demand elasticity, clearly delineates a role for orexin in modulating motivational, rather than the primary reinforcing aspects of drug reward. We also discuss the anatomical interconnectedness of the orexin system with wider motivation and reward circuits, with a particular focus on how orexin modulates prefrontal and other glutamatergic inputs onto ventral tegmental area dopamine neurons. Last, we look ahead to the next decade of the research in this area, highlighting the recent FDA approval of the dual orexin receptor antagonist suvorexant (Belsomra®) for the treatment of insomnia as a promising sign of the potential clinical utility of orexin-based therapies for the treatment of addiction.
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Affiliation(s)
- Morgan H James
- Brain Health Institute, Rutgers University/Rutgers Biomedical and Health Sciences, Piscataway, NJ, 08854, USA
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 2337, Australia
| | - Stephen V Mahler
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, 92967, USA
| | - David E Moorman
- Department of Psychological and Brain Sciences & Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Gary Aston-Jones
- Brain Health Institute, Rutgers University/Rutgers Biomedical and Health Sciences, Piscataway, NJ, 08854, USA.
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129
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Chen XY, Chen L, Du YF. Orexin-A increases the firing activity of hippocampal CA1 neurons through orexin-1 receptors. J Neurosci Res 2016; 95:1415-1426. [PMID: 27796054 DOI: 10.1002/jnr.23975] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/29/2016] [Accepted: 10/04/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Xin-Yi Chen
- Department of Neurology; Provincial Hospital Affiliated to Shandong University; Jinan Shandong China
| | - Lei Chen
- Department of Physiology; Qingdao University; Qingdao China
| | - Yi-Feng Du
- Department of Neurology; Provincial Hospital Affiliated to Shandong University; Jinan Shandong China
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130
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López JM, Morales L, González A. Spatiotemporal Development of the Orexinergic (Hypocretinergic) System in the Central Nervous System of Xenopus laevis. BRAIN, BEHAVIOR AND EVOLUTION 2016; 88:127-146. [DOI: 10.1159/000449278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/18/2016] [Indexed: 11/19/2022]
Abstract
The present immunohistochemical study represents a detailed spatiotemporal analysis of the localization of orexin-immunoreactive (OX-ir) cells and fibers throughout development in the brain of the anuran amphibian Xenopus laevis, a model frequently used in developmental studies. Anurans undergo remarkable physiological changes during the early life stages, and very little is known about the ontogeny and the localization of the centers that control functions such as appetite and feed ingestion in the developing brain. We examined the onset of the orexinergic system, demonstrated to be involved in appetite regulation, using antibodies against mammalian orexin-A and orexin-B peptides. Simultaneous detection of orexins with other territorial markers was used to assess the precise location of the orexinergic cells in the hypothalamus, analyzed within a segmental paradigm. Double staining of orexins and tyrosine hydroxylase served to evaluate possible interactions with the catecholaminergic systems. At early embryonic stages, the first OX-ir cells were detected in the hypothalamus and, soon after, long descending projections were observed through the brainstem to the spinal cord. As brain development proceeded, the double-staining techniques demonstrated that this OX-ir cell group was located in the suprachiasmatic nucleus within the alar hypothalamus. Throughout larval development, the number of OX-ir cells increased notably and a widespread fiber network that innervated the main areas of the forebrain and brainstem was progressively formed, including innervation in the posterior tubercle and mesencephalon, the locus coeruleus, and the nucleus of the solitary tract where catecholaminergic cells are present. In addition, orexinergic cells were detected in the preoptic area and the tuberal hypothalamus only at late prometamorphic stages. The final distribution pattern, largely similar to that of the adult, was achieved through metamorphic climax. The early expression of orexins in Xenopus suggests important roles in brain development in the embryonic period before feeding, and the progression of the temporal and spatial complexity of the orexinergic system might be correlated to the maturation of appetite control regulation, among other functions.
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131
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Orexin/hypocretin-1 receptor antagonism reduces ethanol self-administration and reinstatement selectively in highly-motivated rats. Brain Res 2016; 1654:34-42. [PMID: 27771284 DOI: 10.1016/j.brainres.2016.10.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 12/18/2022]
Abstract
The orexin/hypocretin (ORX) system regulates motivation for natural rewards and drugs of abuse such as alcohol. ORX receptor antagonists, most commonly OX1R antagonists including SB-334867 (SB), decrease alcohol drinking, self-administration and reinstatement in both genetically-bred alcohol-preferring and outbred strains of rats. Importantly, levels of alcohol seeking and drinking in outbred rats are variable, as they are in humans. We have shown that OX1R antagonism selectively decreases homecage alcohol drinking in high-, but not low-alcohol-preferring rats. It is unknown, however, whether this effect is selective to homecage drinking or whether it also applies to alcohol seeking paradigms such as self-administration and reinstatement following extinction, in which motivation is high in the absence of alcohol. Here we trained Sprague Dawley rats to self-administer 20% ethanol paired with a light-tone cue on an FR3 regimen. Rats were then extinguished and subjected to cue-induced reinstatement. Rats were segregated into high- and low-ethanol-responding groups (HR and LR) based on self-administration levels. During self-administration and cue-induced reinstatement, rats were given SB or vehicle prior to ethanol seeking. In both conditions, OX1R antagonism decreased responding selectively in HR, but not LR rats. There were no non-specific effects of SB treatment on arousal or general behavior. These data indicate that ORX signaling at the OX1R receptor specifically regulates high levels of motivation for alcohol, even in the absence of direct alcohol reinforcement. This implicates the ORX system in the pathological motivation underlying alcohol abuse and alcoholism and demonstrates that the OX1R may be an important target for treating alcohol abuse.
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132
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Elbaz I, Zada D, Tovin A, Braun T, Lerer-Goldshtein T, Wang G, Mourrain P, Appelbaum L. Sleep-Dependent Structural Synaptic Plasticity of Inhibitory Synapses in the Dendrites of Hypocretin/Orexin Neurons. Mol Neurobiol 2016; 54:6581-6597. [PMID: 27734337 DOI: 10.1007/s12035-016-0175-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/28/2016] [Indexed: 12/15/2022]
Abstract
Sleep is tightly regulated by the circadian clock and homeostatic mechanisms. Although the sleep/wake cycle is known to be associated with structural and physiological synaptic changes that benefit the brain, the function of sleep is still debated. The hypothalamic hypocretin/orexin (Hcrt) neurons regulate various functions including feeding, reward, sleep, and wake. Continuous imaging of single neuronal circuits in live animals is vital to understanding the role of sleep in regulating synaptic dynamics, and the transparency of the zebrafish model enables time-lapse imaging of single synapses during both day and night. Here, we use the gephyrin (Gphnb) protein, a central inhibitory synapse organizer, as a fluorescent post-synaptic marker of inhibitory synapses. Double labeling showed that Gphnb-tagRFP and collybistin-EGFP clusters co-localized in dendritic inhibitory synapses. Using a transgenic hcrt:Gphnb-EGFP zebrafish, we showed that the number of inhibitory synapses in the dendrites of Hcrt neurons was increased during development. To determine the effect of sleep on the inhibitory synapses, we performed two-photon live imaging of Gphnb-EGFP in Hcrt neurons during day and night, under light/dark and constant light and dark conditions, and following sleep deprivation (SD). We found that synapse number increased during the night under light/dark conditions but that these changes were eliminated under constant light or dark conditions. SD reduced synapse number during the night, and the number increased during post-deprivation daytime sleep rebound. These results suggest that rhythmic structural plasticity of inhibitory synapses in Hcrt dendrites is independent of the circadian clock and is modulated by consolidated wake and sleep.
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Affiliation(s)
- Idan Elbaz
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - David Zada
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Adi Tovin
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Tslil Braun
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Tali Lerer-Goldshtein
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Gordon Wang
- Center for Sleep Sciences and Medicine, Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, 94305, USA
| | - Philippe Mourrain
- Center for Sleep Sciences and Medicine, Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, 94305, USA
- INSERM 1024, Ecole Normale Supérieure, 75005, Paris, France
| | - Lior Appelbaum
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel.
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133
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Zhao Y, Singh C, Prober DA, Wayne NL. Morphological and Physiological Interactions Between GnRH3 and Hypocretin/Orexin Neuronal Systems in Zebrafish (Danio rerio). Endocrinology 2016; 157:4012-4020. [PMID: 27533887 PMCID: PMC5045510 DOI: 10.1210/en.2016-1381] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/11/2016] [Indexed: 01/11/2023]
Abstract
GnRH neurons integrate internal and external cues to control sexual maturation and fertility. Homeostasis of energy balance and food intake correlates strongly with the status of reproduction. Neuropeptides secreted by the hypothalamus involved in modulating energy balance and feeding may play additional roles in the regulation of reproduction. Hypocretin (Hcrt) (also known as orexin) is one such peptide, primarily controlling sleep/wakefulness, food intake, and reward processing. There is a growing body of evidence indicating that Hcrt/orexin (Hcrt) modulates reproduction through interacting with the hypothalamo-pituitary-gonadal axis in mammals. To explore potential morphological and functional interactions between the GnRH and Hcrt neuronal systems, we employed a variety of experimental approaches including confocal imaging, immunohistochemistry, and electrophysiology in transgenic zebrafish, in which fluorescent proteins are genetically expressed in GnRH3 and Hcrt neurons. Our imaging data revealed close apposition and direct connection between GnRH3 and Hcrt neuronal systems in the hypothalamus during larval development through adulthood. Furthermore, the Hcrt receptor (HcrtR) is expressed in GnRH3 neurons. Electrophysiological data revealed a reversible inhibitory effect of Hcrt on GnRH3 neuron electrical activity, which was blocked by the HcrtR antagonist almorexant. In addition, Hcrt had no effect on the electrical activity of GnRH3 neurons in the HcrtR null mutant zebrafish (HcrtR-/-). Our findings demonstrate a close anatomical and functional relationship between Hcrt and GnRH neuronal systems in zebrafish. It is the first demonstration of a link between neuronal circuits controlling sleeping/arousal/feeding and reproduction in zebrafish, an important animal model for investigating the molecular genetics of development.
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Affiliation(s)
- Yali Zhao
- Department of Physiology (Y.Z., N.L.W.), David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095; and Division of Biology and Biological Engineering (C.S., D.P.), California Institute of Technology, Pasadena, California 91125
| | - Chanpreet Singh
- Department of Physiology (Y.Z., N.L.W.), David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095; and Division of Biology and Biological Engineering (C.S., D.P.), California Institute of Technology, Pasadena, California 91125
| | - David A Prober
- Department of Physiology (Y.Z., N.L.W.), David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095; and Division of Biology and Biological Engineering (C.S., D.P.), California Institute of Technology, Pasadena, California 91125
| | - Nancy L Wayne
- Department of Physiology (Y.Z., N.L.W.), David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095; and Division of Biology and Biological Engineering (C.S., D.P.), California Institute of Technology, Pasadena, California 91125
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Abstract
INTRODUCTION 1,2,3,4-Tetrahydroisoquinoline (THIQ) is one of the 'privileged scaffolds', commonly found in nature. Initially, this class of compounds was known for its neurotoxicity. Later on, 1-methyl-1,2,3,4-tetrahydroisoquinoline was proved as an endogeneous Parkinsonism-preventing agent in mammals. The fused THIQs have been studied for their role as anticancer antibiotics. The US FDA approval of the trabectedin for the treatment of soft tissue sarcomas, is a milestone in the anticancer drug discovery. Areas covered: This review covers the patents on various therapeutic activities of the THIQ derivatives in the years between 2010 and 2015. Patents were collected using a thorough search of Espacenet and WIPO databases. The therapeutic areas covered include cancer, malaria, central nervous system (CNS), cardiovascular, metabolic disorders, and so on. This also includes several patents on specific THIQs of clinical importance. Expert opinion: A large number of the THIQ derivatives have been synthesised for various therapeutic activities, with noticeable success in the area of drug discovery for cancer and CNS. They may also prove to be promising candidates for various infectious diseases, such as malaria, tuberculosis, HIV-infection, HSV-infection, leishmaniasis, etc. They can also be developed as novel class of drugs for various therapeutic activities with unique mechanism of action.
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Affiliation(s)
- Inder Pal Singh
- a Department of Natural Products , National Institute of Pharmaceutical Education and Research (NIPER) , Punjab , India
| | - Purvi Shah
- a Department of Natural Products , National Institute of Pharmaceutical Education and Research (NIPER) , Punjab , India
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136
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Orexin, Stress and Central Cardiovascular Control. A Link with Hypertension? Neurosci Biobehav Rev 2016; 74:376-392. [PMID: 27477446 DOI: 10.1016/j.neubiorev.2016.06.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/28/2016] [Accepted: 06/13/2016] [Indexed: 01/28/2023]
Abstract
Orexin, the arousal peptide, originates from neurons located in an area of the dorsal hypothalamus well known for integrating defense responses and their cardiovascular component. Orexin neurons, which are driven in large part by the limbic forebrain, send projections to many regions in the brain, including regions involved in cardiovascular control, as far down as sympathetic preganglionic neurons in the spinal cord. Central injections of orexin evoke sympathetically mediated cardiovascular responses. Conversely, blockade of orexin receptors reduce the cardiovascular responses to acute stressors, preferentially of a psychological nature. More importantly, lasting upregulation of orexin signaling can lead to a hypertensive state. This can be observed in rats exposed to chronic stress as well as in strains known to display spontaneous hypertension such as the spontaneously hypertensive rat (SHR) or the hypertensive BPH/2J Schlager mouse. Thus, there is a link between orexin, stress and hypertension, and orexin upregulation could be a factor in the development of essential hypertension. Orexin receptor antagonists have anti-hypertensive effects that could be of clinical use.
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137
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Xue Y, Yang YT, Liu HY, Chen WF, Chen AQ, Sheng Q, Chen XY, Wang Y, Chen H, Liu HX, Pang YY, Chen L. Orexin-A increases the activity of globus pallidus neurons in both normal and parkinsonian rats. Eur J Neurosci 2016; 44:2247-57. [PMID: 27336845 DOI: 10.1111/ejn.13323] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 05/04/2016] [Accepted: 06/21/2016] [Indexed: 02/06/2023]
Abstract
Orexin is a member of neuropeptides which was first identified in the hypothalamus. The globus pallidus is a key structure in the basal ganglia, which is involved in both normal motor function and movement disorders. Morphological studies have shown the expression of both OX1 and OX2 receptors in the globus pallidus. Employing single unit extracellular recordings and behavioural tests, the direct in vivo electrophysiological and behavioural effects of orexin-A in the globus pallidus were studied. Micro-pressure administration of orexin-A significantly increased the spontaneous firing rate of pallidal neurons. Correlation analysis revealed a negative correlation between orexin-A induced excitation and the basal firing rate. Furthermore, application of the specific OX1 receptor antagonist, SB-334867, decreased the firing rate of pallidal neurons, suggesting that endogenous orexinergic systems modulate the firing activity of pallidal neurons. Orexin-A increased the excitability of pallidal neurons through both OX1 and OX2 receptors. In 6-hydroxydopamine parkinsonian rats, orexin-A-induced increase in firing rate of pallidal neurons was stronger than that in normal rats. Immunostaining revealed positive OX1 receptor expression in the globus pallidus of both normal and parkinsonian rats. Finally, postural test showed that unilateral microinjection of orexin-A led to contralateral deflection in the presence of systemic haloperidol administration. Further elevated body swing test revealed that pallidal orexin-A and SB-334867 induced contralateral-biased swing and ipsilateral-biased swing respectively. Based on the electrophysiological and behavioural findings of orexin-A in the globus pallidus, the present findings may provide a rationale for the pathogenesis and treatment of Parkinson's disease.
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Affiliation(s)
- Yan Xue
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Yu-Ting Yang
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Hong-Yun Liu
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China.,Department of Pathology, Qingdao Municipal Hospital, Qingdao, China
| | - Wen-Fang Chen
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - An-Qi Chen
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Qing Sheng
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Xin-Yi Chen
- Department of Neurology, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Ying Wang
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Hua Chen
- Department of Pathology, Qingdao Municipal Hospital, Qingdao, China
| | - Hong-Xia Liu
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Ya-Yan Pang
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
| | - Lei Chen
- Department of Physiology, Faculty of Medicine, Qingdao University, Qingdao 266071, Shandong, China
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138
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Kastman HE, Blasiak A, Walker L, Siwiec M, Krstew EV, Gundlach AL, Lawrence AJ. Nucleus incertus Orexin2 receptors mediate alcohol seeking in rats. Neuropharmacology 2016; 110:82-91. [PMID: 27395787 DOI: 10.1016/j.neuropharm.2016.07.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/28/2016] [Accepted: 07/05/2016] [Indexed: 11/29/2022]
Abstract
Alcoholism is a chronic relapsing disorder and a major global health problem. Stress is a key precipitant of relapse in human alcoholics and in animal models of alcohol seeking. The brainstem nucleus incertus (NI) contains a population of relaxin-3 neurons that are highly responsive to psychological stressors; and the ascending NI relaxin-3/RXFP3 signalling system is implicated in stress-induced reinstatement of alcohol seeking. The NI receives orexinergic innervation and expresses orexin1 (OX1) and orexin2 (OX2) receptor mRNA. In alcohol-preferring (iP) rats, we examined the impact of yohimbine-induced reinstatement of alcohol seeking on orexin neuronal activation, and the effect of bilateral injections into NI of the OX1 receptor antagonist, SB-334867 (n = 16) or the OX2 receptor antagonist, TCS-OX2-29 (n = 8) on stress-induced reinstatement of alcohol seeking. We also assessed the effects of orexin-A on NI neuronal activity and the involvement of OX1 and OX2 receptors using whole cell patch-clamp recordings in rat brain slices. Yohimbine-induced reinstatement of alcohol seeking activated orexin neurons. Bilateral NI injections of TCS-OX2-29 attenuated yohimbine-induced reinstatement of alcohol seeking. In contrast, intra-NI injection of SB-334867 had no significant effect. In line with these data, orexin-A (600 nM) depolarized a majority of NI neurons recorded in coronal brain slices (18/28 cells), effects prevented by bath application of TCS-OX2-29 (10 μM), but not SB-334867 (10 μM). These data suggest an excitatory orexinergic input to NI contributes to yohimbine-induced reinstatement of alcohol seeking, predominantly via OX2 receptor signalling.
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Affiliation(s)
- Hanna E Kastman
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, 30-387 Krakow, Poland
| | - Leigh Walker
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Marcin Siwiec
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, 30-387 Krakow, Poland
| | - Elena V Krstew
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia.
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139
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Histamine may contribute to vortioxetine's procognitive effects; possibly through an orexigenic mechanism. Prog Neuropsychopharmacol Biol Psychiatry 2016; 68:25-30. [PMID: 26945513 DOI: 10.1016/j.pnpbp.2016.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 02/24/2016] [Accepted: 03/01/2016] [Indexed: 01/06/2023]
Abstract
Vortioxetine is a novel multimodal antidepressant that acts as a serotonin (5-HT)3, 5-HT7, and 5-HT1D receptor antagonist; 5-HT1B receptor partial agonist; 5-HT1A receptor agonist; and 5-HT transporter inhibitor in vitro. In preclinical and clinical studies vortioxetine demonstrates positive effects on cognitive dysfunction. Vortioxetine's effect on cognitive function likely involves the modulation of several neurotransmitter systems. Acute and chronic administration of vortioxetine resulted in changes in histamine concentrations in microdialysates collected from the rat prefrontal cortex and ventral hippocampus. Based on these results and a literature review of the current understanding of the interaction between the histaminergic and serotonergic systems and the role of histamine on cognitive function, we hypothesize that vortioxetine through an activation of the orexinergic system stimulates the tuberomammilary nucleus and enhances histaminergic neurotransmission, which contributes to vortioxetine's positive effects on cognitive function.
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140
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Social stress during lactation, depressed maternal care, and neuropeptidergic gene expression. Behav Pharmacol 2016; 26:642-53. [PMID: 26061353 DOI: 10.1097/fbp.0000000000000147] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Depression and anxiety can be severely detrimental to the health of both the affected woman and her offspring. In a rodent model of postpartum depression and anxiety, chronic social stress exposure during lactation induces deficits in maternal care and increases anxiety. Here, we extend previous findings by expanding the behavioral analyses, assessing lactation, and examining several neural systems within amygdalar and hypothalamic regions involved in the control of the stress response and expression of maternal care that may be mediating the behavioral changes in stressed dams. Compared with control dams, those exposed to chronic social stress beginning on day 2 of lactation show impaired maternal care and lactation and increased maternal anxiety on day 9 of lactation. Saccharin-based anhedonia and maternal aggression were increased and lactation was also impaired on day 16 of lactation. These behavioral changes were correlated with a decrease in oxytocin mRNA expression in the medial amygdala, and increases in the expressions of corticotrophin-releasing hormone mRNA in the central nucleus of the amygdala, glucocorticoid receptor mRNA in the paraventricular nucleus, and orexin 2 receptor mRNA in the supraoptic nucleus of stressed compared with control dams. The increase in glucocorticoid receptor mRNA in the paraventricular nucleus was negatively correlated with methylation of a CpG site in the promoter region. In conclusion, the data support the hypothesis that social stress during lactation can have profound effects on maternal care, lactation, and anxiety, and that these behavioral effects are mediated by central changes in stress and maternally relevant neuropeptide systems.
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141
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Mohammed M, Yanagisawa M, Blessing W, Ootsuka Y. Attenuated cold defense responses in orexin neuron-ablated rats. Temperature (Austin) 2016; 3:465-475. [PMID: 28349086 PMCID: PMC5079225 DOI: 10.1080/23328940.2016.1184366] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/13/2022] Open
Abstract
Recent reports of the use of transgenic mice targeting orexin neurons show that the ablation of orexin neurons in the hypothalamus causes hypothermia during cold exposure. This suggests the importance of orexin neurons for cold-induced autonomic and physiological defense responses, including brown adipose tissue (BAT) thermogenesis and vasoconstriction in thermoregulatory cutaneous vascular bed. The present study investigated whether the ablation of orexin neurons attenuated cold-elicited BAT thermogenesis and cutaneous vasoconstriction. The study took advantage of our established conscious rat experimental model of direct measurement of BAT and body temperature and tail cutaneous blood flow. The study used transgenic orexin neurons-ablated (ORX-AB) rats and wild type (WT) rats. BAT temperature and tail artery blood flow with pre-implanted probes were measured, as well as behavioral locomotor activity under conscious free-moving condition. Gradually, the ambient temperature was decreased to below 5°C. ORX-AB rats showed an attenuated cold-induced BAT thermogenesis and behavioral activity, and delayed tail vasoconstriction. An ambient temperature that initiated BAT thermogenesis and established full cutaneous vasoconstriction was 14.1 ± 1.9 °C, which was significantly lower than 20.5 ± 1.9 °C, the corresponding value in WT rats (n = 10, P < 0.01). The results from this study suggest that the integrity of orexin-synthesising neurons in thermoregulatory networks is important for full expression of the cold defense responses.
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Affiliation(s)
- Mazher Mohammed
- Centre for Neuroscience, Department of Human Physiology, Flinders University , Adelaide, SA, Australia
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Japan; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - William Blessing
- Centre for Neuroscience, Department of Human Physiology, Flinders University , Adelaide, SA, Australia
| | - Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University , Adelaide, SA, Australia
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142
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Jin J, Chen Q, Qiao Q, Yang L, Xiong J, Xia J, Hu Z, Chen F. Orexin neurons in the lateral hypothalamus project to the medial prefrontal cortex with a rostro-caudal gradient. Neurosci Lett 2016; 621:9-14. [PMID: 27048712 DOI: 10.1016/j.neulet.2016.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/18/2016] [Accepted: 04/01/2016] [Indexed: 12/26/2022]
Abstract
Orexin neurons in the lateral hypothalamus (LH) play an important role in arousal, guaranteeing the execution of medial prefrontal cortex (mPFC)-related higher cognitive functions. The mPFC is anatomically and functionally a rostro-caudal hierarchy. Little is known about the innervation pattern, especially in the rostro-caudal model, from the arousal-promoting orexin system in the LH to the mPFC subregions, including the anterior cingulate cortex (AC), prelimbic cortex (PL) and infralimbic cortex (IL). Here, we used an anterograde tracing method and immunohistochemistry and found that the density of the LH, as well as orexinergic, fibers increased from the rostral part to the caudal part of the mPFC, regardless of AC, PL or IL. Similarly, the distribution of type 1 orexin receptors in the mPFC follows a rostro-caudal increasing gradient hierarchy. These data suggest a rostro-caudal hierarchy of LH orexinergic innervation to the mPFC. We hope to provide anatomical and morphological evidence for the regulation pattern of the arousal-promoting orexin system on the cognition-related mPFC system.
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Affiliation(s)
- Jiehua Jin
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China
| | - Quanhui Chen
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China
| | - Qicheng Qiao
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China
| | - Li Yang
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China
| | - Jiaxiang Xiong
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China
| | - Jianxia Xia
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China
| | - Zhian Hu
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China.
| | - Fang Chen
- Department of Physiology, Collaborative Innovation Center for Brain Science, Third Military Medical University, Chongqing, 400038, China.
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143
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Lu GL, Lee CH, Chiou LC. Orexin A induces bidirectional modulation of synaptic plasticity: Inhibiting long-term potentiation and preventing depotentiation. Neuropharmacology 2016; 107:168-180. [PMID: 26965217 DOI: 10.1016/j.neuropharm.2016.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/19/2016] [Accepted: 03/01/2016] [Indexed: 01/30/2023]
Abstract
The orexin system consists of two peptides, orexin A and B and two receptors, OX1R and OX2R. It is implicated in learning and memory regulation while controversy remains on its role in modulating hippocampal synaptic plasticity in vivo and in vitro. Here, we investigated effects of orexin A on two forms of synaptic plasticity, long-term potentiation (LTP) and depotentiation of field excitatory postsynaptic potentials (fEPSPs), at the Schaffer Collateral-CA1 synapse of mouse hippocampal slices. Orexin A (≧30 nM) attenuated LTP induced by theta burst stimulation (TBS) in a manner antagonized by an OX1R (SB-334867), but not OX2R (EMPA), antagonist. Conversely, at 1 pM, co-application of orexin A prevented the induction of depotentiation induced by low frequency stimulation (LFS), i.e. restoring LTP. This re-potentiation effect of sub-nanomolar orexin A occurred at LFS of 1 Hz, but not 2 Hz, and with LTP induced by either TBS or tetanic stimulation. It was significantly antagonized by SB-334867, EMPA and TCS-1102, selective OX1R, OX2R and dual OXR antagonists, respectively, and prevented by D609, SQ22536 and H89, inhibitors of phospholipase C (PLC), adenylyl cyclase (AC) and protein kinase A (PKA), respectively. LFS-induced depotentiation was antagonized by blockers of NMDA, A1-adenosine and type 1/5 metabotropic glutamate (mGlu1/5) receptors, respectively. However, orexin A (1 pM) did not affect chemical-induced depotentiation by agonists of these receptors. These results suggest that orexin A bidirectionally modulates hippocampal CA1 synaptic plasticity, inhibiting LTP via OX1Rs at moderate concentrations while inducing re-potentiation via OX1Rs and OX2Rs, possibly through PLC and AC-PKA signaling at sub-nanomolar concentrations.
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Affiliation(s)
- Guan-Ling Lu
- Graduate Institute and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Hsu Lee
- Graduate Institute and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Lih-Chu Chiou
- Graduate Institute and College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Reserach Center for Chinese Medicine & Acupuncture, China Medical University, Taichung, Taiwan.
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144
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Yin J, Babaoglu K, Brautigam CA, Clark L, Shao Z, Scheuermann TH, Harrell CM, Gotter AL, Roecker AJ, Winrow CJ, Renger JJ, Coleman PJ, Rosenbaum DM. Structure and ligand-binding mechanism of the human OX1 and OX2 orexin receptors. Nat Struct Mol Biol 2016; 23:293-9. [PMID: 26950369 DOI: 10.1038/nsmb.3183] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 02/02/2016] [Indexed: 01/10/2023]
Abstract
The orexin (also known as hypocretin) G protein-coupled receptors (GPCRs) regulate sleep and other behavioral functions in mammals, and are therapeutic targets for sleep and wake disorders. The human receptors hOX1R and hOX2R, which are 64% identical in sequence, have overlapping but distinct physiological functions and potential therapeutic profiles. We determined structures of hOX1R bound to the OX1R-selective antagonist SB-674042 and the dual antagonist suvorexant at 2.8-Å and 2.75-Å resolution, respectively, and used molecular modeling to illuminate mechanisms of antagonist subtype selectivity between hOX1R and hOX2R. The hOX1R structures also reveal a conserved amphipathic α-helix, in the extracellular N-terminal region, that interacts with orexin-A and is essential for high-potency neuropeptide activation at both receptors. The orexin-receptor crystal structures are valuable tools for the design and development of selective orexin-receptor antagonists and agonists.
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Affiliation(s)
- Jie Yin
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kerim Babaoglu
- Department of Structural Chemistry, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - Chad A Brautigam
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lindsay Clark
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Zhenhua Shao
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Thomas H Scheuermann
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Charles M Harrell
- Department of Neuroscience, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - Anthony L Gotter
- Department of Neuroscience, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - Anthony J Roecker
- Department of Medicinal Chemistry, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - Christopher J Winrow
- Department of Neuroscience, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - John J Renger
- Department of Neuroscience, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - Paul J Coleman
- Department of Medicinal Chemistry, Merck Research Laboratories, West Point, Pennsylvania, USA
| | - Daniel M Rosenbaum
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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145
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Adenosine A1 receptors mediate the intracisternal injection of orexin-induced antinociceptive action against colonic distension in conscious rats. J Neurol Sci 2016; 362:106-10. [DOI: 10.1016/j.jns.2016.01.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/13/2016] [Accepted: 01/18/2016] [Indexed: 12/12/2022]
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146
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Liu Y, Zhao Y, Guo L. Effects of orexin A on glucose metabolism in human hepatocellular carcinoma in vitro via PI3K/Akt/mTOR-dependent and -independent mechanism. Mol Cell Endocrinol 2016; 420:208-16. [PMID: 26549689 DOI: 10.1016/j.mce.2015.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/31/2015] [Accepted: 11/02/2015] [Indexed: 12/20/2022]
Abstract
Orexins are hypothalamic neuropeptides that regulate food intake, energy homeostasis, reward system and sleep/wakefulness states. The purpose of this study was to investigate the effects of orexin A on glucose metabolism in human hepatocellular carcinoma cell line, Hep3B, and determine the possible mechanisms. Hep3B cells were incubated with different concentrations of orexin A (10(-9)-10(-7) M) in vitro in the presence or absence of the orexin receptor 1 (OX1R) inhibitor (SB334867), Akt inhibitor (PF-04691502) and mammalian target of rapamycin (mTOR) inhibitor (temsirolimus). Subsequently, OX1R protein expression, glucose transporter 1 (GLUT1) expression, glucose uptake, the mRNA expression of lactate dehydrogenase (LDHA), pyruvate dehydrogenase kinase 1 (PDK1) and pyruvate dehydrogenase B (PDHB), lactate generation and mitochondrial pyruvate dehydrogenase (PDH) enzyme activity were measured. The activity of phosphoinositide 3-kinase (PI3K)/Akt/mTOR signaling was also determined. OX1R was expressed in hepatoma tissues and Hep3B cells. Stimulation of the Hep3B cells with orexin A resulted in a dose-dependent increase of GLUT1 expression and glucose uptake, which was associated with the activation of PI3K/Akt/mTOR pathway. Further, orexin A increased PDHB expression and PDH enzyme activity, decreased LDHA, PDK1 mRNA levels and lactate generation independent of PI3K/Akt/mTOR pathway. Our results demonstrated that orexin A directed the cellular metabolism towards mitochondrial glucose oxidation rather than glycolysis. These findings provide functional evidence of the metabolic actions of orexin A in hepatocellular carcinoma cells.
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Affiliation(s)
- Yuanyuan Liu
- Department of Endocrinology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, 110001, PR China
| | - Yuyan Zhao
- Department of Endocrinology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, 110001, PR China
| | - Lei Guo
- Department of Orthopedic Surgery, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, 110001, PR China.
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147
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Thomas SA. Neuromodulatory signaling in hippocampus-dependent memory retrieval. Hippocampus 2015; 25:415-31. [PMID: 25475876 DOI: 10.1002/hipo.22394] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2014] [Indexed: 12/15/2022]
Abstract
Considerable advances have been made toward understanding the molecular signaling events that underlie memory acquisition and consolidation. In contrast, less is known about memory retrieval, despite its necessity for utilizing learned information. This review focuses on neuromodulatory and intracellular signaling events that underlie memory retrieval mediated by the hippocampus, for which the most information is currently available. Among neuromodulators, adrenergic signaling is required for the retrieval of various types of hippocampus-dependent memory. Although they contribute to acquisition and/or consolidation, cholinergic and dopaminergic signaling are generally not required for retrieval. Interestingly, while not required for retrieval, serotonergic and opioid signaling may actually constrain memory retrieval. Roles for histamine and non-opioid neuropeptides are currently unclear but possible. A critical effector of adrenergic signaling in retrieval is reduction of the slow afterhyperpolarization mediated by β1 receptors, cyclic AMP, protein kinase A, Epac, and possibly ERK. In contrast, stress and glucocorticoids impair retrieval by decreasing cyclic AMP, mediated in part by the activation of β2 -adrenergic receptors. Clinically, alterations in neuromodulatory signaling and in memory retrieval occur in Alzheimer's disease, Down syndrome, depression, and post-traumatic stress disorder, and recent evidence has begun to link changes in neuromodulatory signaling with effects on memory retrieval.
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Affiliation(s)
- Steven A Thomas
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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148
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Sutton EL. Profile of suvorexant in the management of insomnia. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:6035-42. [PMID: 26648692 PMCID: PMC4651361 DOI: 10.2147/dddt.s73224] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Suvorexant, approved in late 2014 in the United States and Japan for the treatment of insomnia characterized by difficulty achieving and/or maintaining sleep, is a dual orexin receptor antagonist and the first drug in its class to reach the market. Its development followed from the 1998 discovery of orexins (also called hypocretins), excitatory neuropeptides originating from neurons in the hypothalamus involved in regulation of sleep and wake, feeding behavior and energy regulation, motor activity, and reward-seeking behavior. Suvorexant objectively improves sleep, shortening the time to achieve persistent sleep and reducing wake after sleep onset, although at approved doses (≤20 mg) the benefit was subjectively assessed as modest. Its half-life of 12 hours is relatively long for a modern hypnotic; however, at approved doses (≤20 mg) next-day sedation and driving impairment were much less apparent than at higher doses. Suvorexant is metabolized by the hepatic CYP3A system and should be avoided in combination with strong CYP3A inhibitors. Drug levels are higher in women and obese people; hence, dosing should be conservative in obese women. Administration with food delays drug absorption and is not advised. No dose adjustment is needed for advanced age, renal impairment, or mild-to-moderate hepatic impairment. Suvorexant in contraindicated in narcolepsy and has not been studied in children. In alignment with the changes begun in 2013 in the labeling of other hypnotics, the United States Food and Drug Administration advises that the lowest dose effective to treat symptoms be used and that patients be advised of the possibility of next-day impairment in function, including driving. Infrequent but notable side effects included abnormal dreams, sleep paralysis, and suicidal ideation that were dose-related and reported to be mild. Given its mechanism of action, cataplexy and rapid eye movement (REM) sleep behavior disorder could potentially occur in some patients taking this medication.
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Affiliation(s)
- Eliza L Sutton
- Department of Medicine, University of Washington, Seattle, WA, USA
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149
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Chang GQ, Karatayev O, Leibowitz SF. Prenatal exposure to ethanol stimulates hypothalamic CCR2 chemokine receptor system: Possible relation to increased density of orexigenic peptide neurons and ethanol drinking in adolescent offspring. Neuroscience 2015; 310:163-75. [PMID: 26365610 DOI: 10.1016/j.neuroscience.2015.09.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/03/2015] [Accepted: 09/07/2015] [Indexed: 12/14/2022]
Abstract
Clinical and animal studies indicate that maternal consumption of ethanol during pregnancy increases alcohol drinking in the offspring. Possible underlying mechanisms may involve orexigenic peptides, which are stimulated by prenatal ethanol exposure and themselves promote drinking. Building on evidence that ethanol stimulates neuroimmune factors such as the chemokine CCL2 that in adult rats is shown to colocalize with the orexigenic peptide, melanin-concentrating hormone (MCH) in the lateral hypothalamus (LH), the present study sought to investigate the possibility that CCL2 or its receptor CCR2 in LH is stimulated by prenatal ethanol exposure, perhaps specifically within MCH neurons. Our paradigm of intraoral administration of ethanol to pregnant rats, at low-to-moderate doses (1 or 3g/kg/day) during peak hypothalamic neurogenesis, caused in adolescent male offspring twofold increase in drinking of and preference for ethanol and reinstatement of ethanol drinking in a two-bottle choice paradigm under an intermittent access schedule. This effect of prenatal ethanol exposure was associated with an increased expression of MCH and density of MCH(+) neurons in LH of preadolescent offspring. Whereas CCL2(+) cells at this age were low in density and unaffected by ethanol, CCR2(+) cells were dense in LH and increased by prenatal ethanol, with a large percentage (83-87%) identified as neurons and found to colocalize MCH. Prenatal ethanol also stimulated the genesis of CCR2(+) and MCH(+) neurons in the embryo, which co-labeled the proliferation marker, BrdU. Ethanol also increased the genesis and density of neurons that co-expressed CCR2 and MCH in LH, with triple-labeled CCR2(+)/MCH(+)/BrdU(+) neurons that were absent in control rats accounting for 35% of newly generated neurons in ethanol-exposed rats. With both the chemokine and MCH systems believed to promote ethanol consumption, this greater density of CCR2(+)/MCH(+) neurons in the LH of preadolescent rats suggests that these systems function together in promoting alcohol drinking during adolescence.
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Affiliation(s)
- G-Q Chang
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY 10065, USA
| | - O Karatayev
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY 10065, USA
| | - S F Leibowitz
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY 10065, USA.
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150
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Flores Á, Saravia R, Maldonado R, Berrendero F. Orexins and fear: implications for the treatment of anxiety disorders. Trends Neurosci 2015. [DOI: 10.1016/j.tins.2015.06.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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