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Mavanji V, Pomonis BL, Shekels L, Kotz CM. Interactions between Lateral Hypothalamic Orexin and Dorsal Raphe Circuitry in Energy Balance. Brain Sci 2024; 14:464. [PMID: 38790443 PMCID: PMC11117928 DOI: 10.3390/brainsci14050464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/30/2024] [Accepted: 05/04/2024] [Indexed: 05/26/2024] Open
Abstract
Orexin/hypocretin terminals innervate the dorsal raphe nucleus (DRN), which projects to motor control areas important for spontaneous physical activity (SPA) and energy expenditure (EE). Orexin receptors are expressed in the DRN, and obesity-resistant (OR) rats show higher expression of these receptors in the DRN and elevated SPA/EE. We hypothesized that orexin-A in the DRN enhances SPA/EE and that DRN-GABA modulates the effect of orexin-A on SPA/EE. We manipulated orexin tone in the DRN either through direct injection of orexin-A or through the chemogenetic activation of lateral-hypothalamic (LH) orexin neurons. In the orexin neuron activation experiment, fifteen minutes prior to the chemogenetic activation of orexin neurons, the mice received either the GABA-agonist muscimol or antagonist bicuculline injected into the DRN, and SPA/EE was monitored for 24 h. In a separate experiment, orexin-A was injected into the DRN to study the direct effect of DRN orexin on SPA/EE. We found that the activation of orexin neurons elevates SPA/EE, and manipulation of GABA in the DRN does not alter the SPA response to orexin neuron activation. Similarly, intra-DRN orexin-A enhanced SPA and EE in the mice. These results suggest that orexin-A in the DRN facilitates negative energy balance by increasing physical activity-induced EE, and that modulation of DRN orexin-A is a potential strategy to promote SPA and EE.
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Affiliation(s)
- Vijayakumar Mavanji
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Brianna L. Pomonis
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Laurie Shekels
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Catherine M. Kotz
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
- Geriatric Research, Education and Clinical Center, Minneapolis VA Health Care System, Minneapolis, MN 55417, USA
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Braun A, Manavis J, Yamanaka A, Ootsuka Y, Blumbergs P, Bobrovskaya L. The role of orexin in Parkinson's disease. J Neurosci Res 2024; 102:e25322. [PMID: 38520160 DOI: 10.1002/jnr.25322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 02/28/2024] [Accepted: 03/09/2024] [Indexed: 03/25/2024]
Abstract
Emerging evidence has implicated the orexin system in non-motor pathogenesis of Parkinson's disease. It has also been suggested the orexin system is involved in the modulation of motor control, further implicating the orexin system in Parkinson's disease. Parkinson's disease is the second most common neurodegenerative disease with millions of people suffering worldwide with motor and non-motor symptoms, significantly affecting their quality of life. Treatments are based solely on symptomatic management and no cure currently exists. The orexin system has the potential to be a treatment target in Parkinson's disease, particularly in the non-motor stage. In this review, the most current evidence on the orexin system in Parkinson's disease and its potential role in motor and non-motor symptoms of the disease is summarized. This review begins with a brief overview of Parkinson's disease, animal models of the disease, and the orexin system. This leads into discussion of the possible roles of orexin neurons in Parkinson's disease and levels of orexin in the cerebral spinal fluid and plasma in Parkinson's disease and animal models of the disease. The role of orexin is then discussed in relation to symptoms of the disease including motor control, sleep, cognitive impairment, psychological behaviors, and the gastrointestinal system. The neuroprotective effects of orexin are also summarized in preclinical models of the disease.
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Affiliation(s)
- Alisha Braun
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Jim Manavis
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | | | - Youichirou Ootsuka
- College of Medicine and Public Health, Flinders Medical and Health Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Peter Blumbergs
- Discipline of Anatomy and Pathology, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Larisa Bobrovskaya
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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3
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Chen PY, Chiu CC, Chang CK, Lu ML, Huang CY, Chen CH, Huang MC. Higher orexin-A levels are associated with treatment response to clozapine in patients with schizophrenia: A cross-sectional study. J Psychopharmacol 2024; 38:258-267. [PMID: 38279671 DOI: 10.1177/02698811231225610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
BACKGROUND Clozapine is the primary antipsychotic (APD) for treatment-resistant schizophrenia (TRS). However, only 40% of patients with TRS respond to clozapine, constituting a subgroup of clozapine-resistant patients. Recently, the neuropeptide orexin-A was shown to be involved in the pathophysiology of schizophrenia. This study evaluated the association of orexin-A levels with the clozapine response in patients with TRS. METHODS We recruited 199 patients with schizophrenia, including 37 APD-free and 162 clozapine-treated patients. Clozapine-treated patients were divided into clozapine-responsive (n = 100) and clozapine-resistant (n = 62) groups based on whether they had achieved psychotic remission defined by the 18-item Brief Psychiatric Rating Scale (BPRS-18). We compared blood orexin-A levels among the three groups and performed regression analysis to determine the association of orexin-A level with treatment response in clozapine-treated patients. We also explored the correlation between orexin-A levels and cognitive function, assessed using the CogState Schizophrenia Battery. RESULTS Clozapine-responsive patients had higher orexin-A levels than clozapine-resistant and APD-free patients. Orexin-A level was the only factor significantly associated with treatment response after adjustment. Orexin-A levels were negatively correlated with BPRS-18 full scale and positive, negative, and general symptoms subscale scores. We also observed a positive correlation between orexin-A levels and verbal memory, visual learning and memory, and working memory function. CONCLUSIONS This cross-sectional study showed that higher levels of orexin-A are associated with treatment response to clozapine in patients with TRS. Future prospective studies examining changes in orexin-A level following clozapine treatment and the potential benefit of augmenting orexin-A signaling are warranted.
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Affiliation(s)
- Po-Yu Chen
- Department of Psychiatry, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan
- Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Psychology, National Chengchi University, Taipei, Taiwan
| | - Chih-Chiang Chiu
- Department of Psychiatry, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan
- Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chin-Kuo Chang
- Global Health Program, College of Public Health, National Taiwan University, Taipei, Taiwan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Mong-Liang Lu
- Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Psychiatric Research Center, Wang-Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Cho-Yin Huang
- Department of Psychiatry, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan
| | - Chun-Hsin Chen
- Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Psychiatric Research Center, Wang-Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Ming-Chyi Huang
- Department of Psychiatry, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan
- Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Psychiatric Research Center, Wang-Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Psychiatric Research Center, Taipei Medical University Hospital, Taipei, Taiwan
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Ibeas K, Griñán‐Ferré C, del Mar Romero M, Sebastián D, Bastías‐Pérez M, Gómez R, Soler‐Vázquez MC, Zagmutt S, Pallás M, Castell M, Belsham DD, Mera P, Herrero L, Serra D. Cpt1a silencing in AgRP neurons improves cognitive and physical capacity and promotes healthy aging in male mice. Aging Cell 2024; 23:e14047. [PMID: 37994388 PMCID: PMC10861206 DOI: 10.1111/acel.14047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 11/08/2023] [Accepted: 11/10/2023] [Indexed: 11/24/2023] Open
Abstract
Orexigenic neurons expressing agouti-related protein (AgRP) and neuropeptide Y in the arcuate nucleus (ARC) of the hypothalamus are activated in response to dynamic variations in the metabolic state, including exercise. We previously observed that carnitine palmitoyltransferase 1a (CPT1A), a rate-limiting enzyme of mitochondrial fatty acid oxidation, is a key factor in AgRP neurons, modulating whole-body energy balance and fluid homeostasis. However, the effect of CPT1A in AgRP neurons in aged mice and during exercise has not been explored yet. We have evaluated the physical and cognitive capacity of adult and aged mutant male mice lacking Cpt1a in AgRP neurons (Cpt1a KO). Adult Cpt1a KO male mice exhibited enhanced endurance performance, motor coordination, locomotion, and exploration compared with control mice. No changes were observed in anxiety-related behavior, cognition, and muscle strength. Adult Cpt1a KO mice showed a reduction in gastrocnemius and tibialis anterior muscle mass. The cross-sectional area (CSA) of these muscles were smaller than those of control mice displaying a myofiber remodeling from type II to type I fibers. In aged mice, changes in myofiber remodeling were maintained in Cpt1a KO mice, avoiding loss of physical capacity during aging progression. Additionally, aged Cpt1a KO mice revealed better cognitive skills, reduced inflammation, and oxidative stress in the hypothalamus and hippocampus. In conclusion, CPT1A in AgRP neurons appears to modulate health and protects against aging. Future studies are required to clarify whether CPT1A is a potential antiaging candidate for treating diseases affecting memory and physical activity.
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Affiliation(s)
- Kevin Ibeas
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN)Instituto de Salud Carlos IIIMadridSpain
| | - Christian Griñán‐Ferré
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNEDInstituto de Salud Carlos IIIMadridSpain
| | - Maria del Mar Romero
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN)Instituto de Salud Carlos IIIMadridSpain
| | - David Sebastián
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM)Instituto de Salud Carlos IIIMadridSpain
| | - Marianela Bastías‐Pérez
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
- Present address:
Facultad de Salud y Ciencias SocialesUniversidad de las AméricasSantiago de ChileChile
| | - Roberto Gómez
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
| | - M. Carmen Soler‐Vázquez
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
| | - Sebastián Zagmutt
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
| | - Mercè Pallás
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNEDInstituto de Salud Carlos IIIMadridSpain
| | - Margarida Castell
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN)Instituto de Salud Carlos IIIMadridSpain
- Institut de Recerca en Nutrició i Seguretat Alimentària (INSA‐UB), Universitat de BarcelonaSanta Coloma de GramenetSpain
| | - Denise D. Belsham
- Department of Physiology, Obstetrics and Gynaecology and MedicineUniversity of TorontoTorontoOntarioCanada
| | - Paula Mera
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
| | - Laura Herrero
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN)Instituto de Salud Carlos IIIMadridSpain
| | - Dolors Serra
- Department of Biochemistry and Physiology, School of Pharmacy and Food SciencesUniversitat de BarcelonaBarcelonaSpain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN)Instituto de Salud Carlos IIIMadridSpain
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Gessner NR, Peiravi M, Zhang F, Yimam S, Springer D, Harbison ST. A conserved role for frizzled in sleep architecture. SLEEP ADVANCES : A JOURNAL OF THE SLEEP RESEARCH SOCIETY 2023; 4:zpad045. [PMID: 38033424 PMCID: PMC10684271 DOI: 10.1093/sleepadvances/zpad045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/03/2023] [Indexed: 12/02/2023]
Abstract
Previous studies of natural variants in Drosophila melanogaster implicated the Wnt signaling receptor frizzled in sleep. Given that the Wnt signaling pathway is highly conserved across species, we hypothesized that frizzled class receptor 1 (Fzd1), the murine homolog of frizzled, would also have a role in sleep. Using a CRISPR transgenic approach, we removed most of the Fzd1 coding region from C57BL/6N mice. We used a video assay to measure sleep characteristics in Fzd1-deficient mice. As Wnt signaling is known to affect visuospatial memory, we also examined the impact of the deletion on learning and memory using the novel object recognition (NOR) paradigm. Fzd1-deficient mice had altered sleep compared to littermate controls. The mice did not respond differently to the NOR paradigm compared to controls but did display anxiety-like behavior. Our strategy demonstrates that the study of natural variation in Drosophila sleep translates into candidate genes for sleep in vertebrate species such as the mouse.
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Affiliation(s)
- Nicholas R Gessner
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Morteza Peiravi
- Murine Phenotyping Core, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Fan Zhang
- Transgenic Core, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Shemsiya Yimam
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Danielle Springer
- Murine Phenotyping Core, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Susan T Harbison
- Laboratory of Systems Genetics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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Zokaei L, Akbari E, Babapour V, Zendehdel M. The Modulatory Role of Orexin 1 Receptor in Nucleus Accumbens (NAc) on Spatial Memory in Rats. ARCHIVES OF RAZI INSTITUTE 2023; 78:1285-1294. [PMID: 38226387 PMCID: PMC10787936 DOI: 10.32592/ari.2023.78.4.1285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 01/17/2024]
Abstract
Neuropeptide orexin mainly exists in neurons within and around the lateral hypothalamus and exhibits high affinity to orexin 1 and 2 receptors (OX1R and OX2R, respectively). Orexinergic neurons send their axons to the nucleus accumbens (NAc), which expresses OX1Rs. Previous studies have shown the involvement of orexins and their role in learning and memory processes in the dorsal raphe nucleus and hippocampus. However, no study has examined the effects of orexins in the NAc on memory. The present study examined the effect of the post-training and pre-probe trial intra-NAc administration of SB-33486-A (OX1R antagonist, 12 μg/0.5μl) and TCS-OX2-29 (OX2R antagonist, 10 μg/0.5 μl) on the consolidation and retrieval of memory in the Morris Water Maze (MWM) task. In experiment 1, rats were trained in the MWM and, immediately after every training, received bilateral injections of dimethyl sulfoxide (DMSO) (control group), SB-334867-A (SB), and TCS-OX2-29 (TCS) into the NAc. Experiment 2 was similar to experiment 1, except that the rats received DMSO, SB, and TCS 15 min before the probe test. Probe and visible tests were performed after the last training, and the distance moved, escape latency, and velocity were recorded. In experiment 3, rats trained in experiments 1 and 2, immediately after the probe test, were given the trials for visuomotor coordination assessment on the visible platform. According to the results, the injection of SB increased the distance moved and escape latency in the treated groups, compared to the control group, in the consolidation phase of spatial memory (P<0.05) but not in its retrieval phase (P>0.05). However, TCS-OX2-29 had no effect. These results suggest that the inactivation of the NAc OX1Rs, but not OX2Rs, impairs the consolidation but not the retrieval of spatial memory in rats.
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Affiliation(s)
- L Zokaei
- Department of Basic Sciences, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - E Akbari
- Department of Physiology and Pharmacology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
- Immunogenetics Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - V Babapour
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, 14155-6453, Tehran, Iran
| | - M Zendehdel
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, 14155-6453, Tehran, Iran
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Mazur F, Całka J. Hypothalamic orexins as possible therapeutic agents in threat and spatial memory disorders. Front Behav Neurosci 2023; 17:1228056. [PMID: 37576933 PMCID: PMC10412936 DOI: 10.3389/fnbeh.2023.1228056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/13/2023] [Indexed: 08/15/2023] Open
Abstract
Orexin-A and orexin-B, neuropeptides produced exclusively in the lateral hypothalamus, have been implicated in various functions, including memory. Their levels are elevated in certain pathological states, such as PTSD, and lowered in other states, e.g., memory deficits. Recent developments have shown the possibilities of using orexins to modulate memory. Their administration can improve the results of test animals in paradigms such as passive avoidance (PA), cued fear conditioning (CFC), and the Morris water maze (MWM), with differences between the orexin used and the route of drug administration. Blocking orexin receptors in different brain structures produces opposing effects of memory impairments in given paradigms. Therefore, influencing the orexinergic balance of the brain becomes a viable way to ameliorate memory deficits, shift PTSD-induced recall of stressful memories to an extinction path, or regulate other memory processes.
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Affiliation(s)
- Filip Mazur
- Department of Clinical Physiology, Faculty of Veterinary Medicine, University of Warmia and Masuria in Olsztyn, Olsztyn, Poland
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Kostansek JA, Latona GJ, Heruye SH, Matthews S, Bockman CS, Simeone KA, Simeone TA. Orexin receptors regulate hippocampal sharp wave-ripple complexes in ex vivo slices. Eur J Pharmacol 2023; 950:175763. [PMID: 37146705 DOI: 10.1016/j.ejphar.2023.175763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/13/2023] [Accepted: 05/02/2023] [Indexed: 05/07/2023]
Abstract
Orexin is a neuromodulatory peptide produced by lateral hypothalamic orexin neurons and binds to G-protein-coupled orexin-1 receptor and orexin-2 receptors. Whether orexin modulates learning and memory is not fully understood. Orexin has biphasic effects on learning and memory: promoting learning and memory at homeostatic levels and inhibiting at supra- and sub-homeostatic levels. Hippocampal sharp wave-ripples encode memory information and are essential for memory consolidation and retrieval. The role of orexin on sharp wave-ripples in hippocampal CA1 remains unknown. Here, we used multi-electrode array recordings in acute ex vivo hippocampal slices to determine the effects of orexin receptor antagonists on sharp wave-ripples. Bath-application of either the orexin-1 receptor antagonist N-(2-Methyl-6-benzoxazolyl)-N'-1,5-naphthyridin-4-yl urea (SB-334867) or the orexin-2 receptor antagonist N-Ethyl-2-[(6-methoxy-3-pyridinyl)[(2-methylphenyl)sulfonyl]amino]-N-(3-pyridinylmethyl)-acetamide (EMPA) reduced sharp wave and ripple incidence, sharp wave amplitude, and sharp wave duration. SB-334867 and EMPA effects on sharp wave amplitude and duration were equivalent, whereas EMPA exhibited a greater reduction of sharp wave and ripple incidence. EMPA also increased ripple duration, whereas SB-334867 had no effect. Inhibition of both orexin receptors with a dual orexin receptor antagonist N-[1,1'-Biphenyl]-2-yl-1-[2-[(1-methyl-1H-benzimidazol-2-yl)thio]acetyl-2-pyrrolidinedicarboxamide (TCS-1102) had effects similar to EMPA, however, sharp wave amplitude and duration were unaffected. Region-specific expression of orexin receptors suggests orexin may regulate sharp wave generation in CA3, dentate gyrus-mediated sharp wave modification, sharp wave propagation to CA1, and local ripple emergence in CA1. Our study indicates an orexin contribution to hippocampal sharp wave-ripple complexes and suggests a mechanism by which sub-homeostatic concentrations of orexin may inhibit learning and memory function.
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Affiliation(s)
- Joseph A Kostansek
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA.
| | - Gavin J Latona
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Segewkal H Heruye
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Stephanie Matthews
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Charles S Bockman
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Kristina A Simeone
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Timothy A Simeone
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA.
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9
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Acupuncture Interventions for Alzheimer’s Disease and Vascular Cognitive Disorders: A Review of Mechanisms. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:6080282. [PMID: 36211826 PMCID: PMC9534683 DOI: 10.1155/2022/6080282] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/24/2022] [Accepted: 09/15/2022] [Indexed: 11/23/2022]
Abstract
Cognitive impairment (CI) related to Alzheimer's disease (AD) and vascular cognitive disorders (VCDs) has become a key problem worldwide. Importantly, CI is a neuropsychiatric abnormality mainly characterized by learning and memory impairments. The hippocampus is an important brain region controlling learning and memory. Recent studies have highlighted the effects of acupuncture on memory deficits in AD and VCDs. By reviewing the literature published on this topic in the past five years, the present study intends to summarize the effects of acupuncture on memory impairment in AD and VCDs. Focusing on hippocampal synaptic plasticity, we reviewed the mechanisms underlying the effects of acupuncture on memory impairments through regulation of synaptic proteins, AD characteristic proteins, intestinal microbiota, neuroinflammation, microRNA expression, orexin system, energy metabolism, etc., suggesting that hippocampal synaptic plasticity may be the common as well as the core link underlying the above mechanisms. We also discussed the potential strategies to improve the effect of acupuncture. Additionally, the effects of acupuncture on synaptic plasticity through the regulation of vascular–glia–neuron unit were further discussed.
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Bingul A, Merlin S, Carrive P, Killcross S, Furlong TM. Targeting the lateral hypothalamus with short hairpin RNAs reduces habitual behaviour following extended instrumental training in rats. Neurobiol Learn Mem 2022; 193:107657. [DOI: 10.1016/j.nlm.2022.107657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/23/2022] [Accepted: 06/28/2022] [Indexed: 10/17/2022]
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Ren J, Chen Y, Fang X, Wang D, Wang Y, Yu L, Wu Z, Liu R, Zhang C. Correlation of Orexin-A and brain-derived neurotrophic factor levels in metabolic syndrome and cognitive impairment in schizophrenia treated with clozapine. Neurosci Lett 2022; 782:136695. [PMID: 35618081 DOI: 10.1016/j.neulet.2022.136695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/12/2022] [Accepted: 05/20/2022] [Indexed: 10/18/2022]
Abstract
Orexin-A and brain-derived neurotrophic factor (BDNF) are implicated in regulating metabolic syndrome (MetS) and cognitive impairment of schizophrenia. However, the associations among them remains unclear. Here, we aimed to investigate the relationship between Orexin-A levels, BDNF, MetS, clinical symptom profile, and cognitive function in schizophrenia patients following long-term clozapine treatment. We measured Orexin-A and BDNF levels in 140 schizophrenia patients with and without MetS. We assessed clinical symptoms on the Positive and Negative Syndrome Scale and cognitive function by the assessment of Neuropsychological Status (RBANS), and examined their associations with Orexin-A. Patients with MetS had significantly lower Orexin-A levels and higher coding test, attention span and delayed retention in RBANS (P < 0.05). Correlation analysis showed that Orexin-A was associated with BDNF, TG, HDLC, PANSS active social avoidance and emotional withdrawal significantly. Besides, Orexin-A significantly interacted with BDNF for metabolic and cognitive profiles including waist circumference, delayed retention and list recognition. Logistic regression analysis showed that Orexin-A level (odds ratio [OR]= 0.380, 95% confidence interval [CI]: 0.151-0.952, P = 0.039) and total illness duration (OR = 0.932, 95% CI: 0.875-0.991, P = 0.025) were predictive variables of MetS. However, there was no significant relationship between Orexin-A and cognitive function after adjustment for age, sex and educational levels. Totally, a lower plasma Orexin-A level seems to be related to metabolic parameters more than cognitive profiles. The interaction of Orexin-A with BDNF may be partly responsible for worse MetS and better cognition of elderly schizophrenia, but the causal relationship needs further clarification.
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Affiliation(s)
- Juanjuan Ren
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Chen
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xinyu Fang
- The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China
| | - Dandan Wang
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - YeWei Wang
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - LingFang Yu
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zenan Wu
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ruimei Liu
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Zhang
- Schizophrenia Program, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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12
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Abstract
The hypocretins (Hcrts), also known as orexins, are two neuropeptides produced exclusively in the lateral hypothalamus. They act on two specific receptors that are widely distributed across the brain and involved in a myriad of neurophysiological functions that include sleep, arousal, feeding, reward, fear, anxiety and cognition. Hcrt cell loss in humans leads to narcolepsy with cataplexy (narcolepsy type 1), a disorder characterized by intrusions of sleep into wakefulness, demonstrating that the Hcrt system is nonredundant and essential for sleep/wake stability. The causal link between Hcrts and arousal/wakefulness stabilisation has led to the development of a new class of drugs, Hcrt receptor antagonists to treat insomnia, based on the assumption that blocking orexin-induced arousal will facilitate sleep. This has been clinically validated: currently, two Hcrt receptor antagonists are approved to treat insomnia (suvorexant and lemborexant), with a New Drug Application recently submitted to the US Food and Drug Administration for a third drug (daridorexant). Other therapeutic applications under investigation include reduction of cravings in substance-use disorders and prevention of neurodegenerative disorders such as Alzheimer's disease, given the apparent bidirectional relationship between poor sleep and worsening of the disease. Circuit neuroscience findings suggest that the Hcrt system is a hub that integrates diverse inputs modulating arousal (e.g., circadian rhythms, metabolic status, positive and negative emotions) and conveys this information to multiple output regions. This neuronal architecture explains the wealth of physiological functions associated with Hcrts and highlights the potential of the Hcrt system as a therapeutic target for a number of disorders. We discuss present and future possible applications of drugs targeting the Hcrt system for the treatment of circuit-related neuropsychiatric and neurodegenerative conditions.
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Affiliation(s)
- Laura H Jacobson
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia.,Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Daniel Hoyer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia.,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California, USA
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13
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Levine AS, Jewett DC, Kotz CM, Olszewski PK. Behavioral plasticity: Role of neuropeptides in shaping feeding responses. Appetite 2022; 174:106031. [PMID: 35395362 DOI: 10.1016/j.appet.2022.106031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/12/2022] [Accepted: 03/29/2022] [Indexed: 11/28/2022]
Abstract
Behavioral plasticity refers to changes occurring due to external influences on an organism, including adaptation, learning, memory and enduring influences from early life experience. There are 2 types of behavioral plasticity: "developmental", which refers to gene/environment interactions affecting a phenotype, and "activational" which refers to innate physiology and can involve structural physiological changes of the body. In this review, we focus on feeding behavior, and studies involving neuropeptides that influence behavioral plasticity - primarily opioids, orexin, neuropeptide Y, and oxytocin. In each section of the review, we include examples of behavioral plasticity as it relates to actions of these neuropeptides. It can be concluded from this review that eating behavior is influenced by a number of external factors, including time of day, type of food available, energy balance state, and stressors. The reviewed work underscores that environmental factors play a critical role in feeding behavior and energy balance, but changes in eating behavior also result from a multitude of non-environmental factors, such that there can be no single mechanism or variable that can explain ingestive behavior.
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Affiliation(s)
- Allen S Levine
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, 55113, USA.
| | - David C Jewett
- Department of Psychology, University of Wisconsin-Eau Claire, Eau Claire, WI, USA
| | - Catherine M Kotz
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, 55414, USA; Geriatric, Research, Education and Clinical Center, Minneapolis Veterans Affairs Health, Minneapolis, MN, 55417, USA
| | - Pawel K Olszewski
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, 55113, USA; Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, 55414, USA; Faculty of Science and Engineering, University of Waikato, Hamilton, 3240, New Zealand
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14
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Hanke JM, Schindler KA, Seiler A. On the relationships between epilepsy, sleep, and Alzheimer's disease: A narrative review. Epilepsy Behav 2022; 129:108609. [PMID: 35176650 DOI: 10.1016/j.yebeh.2022.108609] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/01/2022] [Accepted: 02/01/2022] [Indexed: 12/21/2022]
Abstract
Epilepsy, sleep, and Alzheimer's disease (AD) are tightly and potentially causally interconnected. The aim of our review was to investigate current research directions on these relationships. Our hope is that they may indicate preventive measures and new treatment options for early neurodegeneration. We included articles that assessed all three topics and were published during the last ten years. We found that this literature corroborates connections on various pathophysiological levels, including sleep-stage-related epileptiform activity in AD, the negative consequences of different sleep disorders on epilepsy and cognition, common biochemical pathways as well as network dysfunctions. Here we provide a detailed overview of these topics and we discuss promising diagnostic and therapeutic consequences.
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Affiliation(s)
- Julie M Hanke
- Department of Neurology, Inselspital, Sleep-Wake-Epilepsy-Center, Bern University Hospital, University Bern, Bern, Switzerland
| | - Kaspar A Schindler
- Department of Neurology, Inselspital, Sleep-Wake-Epilepsy-Center, Bern University Hospital, University Bern, Bern, Switzerland
| | - Andrea Seiler
- Department of Neurology, Inselspital, Sleep-Wake-Epilepsy-Center, Bern University Hospital, University Bern, Bern, Switzerland.
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15
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Elahdadi Salmani M, Sarfi M, Goudarzi I. Hippocampal orexin receptors: Localization and function. VITAMINS AND HORMONES 2022; 118:393-421. [PMID: 35180935 DOI: 10.1016/bs.vh.2021.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Orexin (hypocretin) is secreted from the perifornical/lateral hypothalamus and is well known for sleep regulation. Orexin has two, orexin A and B, transcripts and two receptors, type 1 and 2 (OX1R and OX2R), located in the plasma membrane of neurons in different brain areas, including the hippocampus involved in learning, memory, seizures, and epilepsy, as physiologic and pathologic phenomena. OX1R is expressed in the dentate gyrus and CA1 and the OX2R in the CA3 areas. Orexin enhances learning and memory as well as reward, stress, seizures, and epilepsy, partly through OX1Rs, while either aggravating or alleviating those phenomena via OX2Rs. OX1Rs activation induces long-term changes of synaptic responses in the hippocampus, an age and concentration-dependent manner. Briefly, we will review the localization and functions of hippocampal orexin receptors, their role in learning, memory, stress, reward, seizures, epilepsy, and hippocampal synaptic plasticity.
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Affiliation(s)
| | | | - Iran Goudarzi
- School of Biology, Damghan University, Damghan, Iran
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16
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Parent MB, Higgs S, Cheke LG, Kanoski SE. Memory and eating: A bidirectional relationship implicated in obesity. Neurosci Biobehav Rev 2022; 132:110-129. [PMID: 34813827 PMCID: PMC8816841 DOI: 10.1016/j.neubiorev.2021.10.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/17/2021] [Accepted: 10/28/2021] [Indexed: 01/03/2023]
Abstract
This paper reviews evidence demonstrating a bidirectional relationship between memory and eating in humans and rodents. In humans, amnesia is associated with impaired processing of hunger and satiety cues, disrupted memory of recent meals, and overconsumption. In healthy participants, meal-related memory limits subsequent ingestive behavior and obesity is associated with impaired memory and disturbances in the hippocampus. Evidence from rodents suggests that dorsal hippocampal neural activity contributes to the ability of meal-related memory to control future intake, that endocrine and neuropeptide systems act in the ventral hippocampus to provide cues regarding energy status and regulate learned aspects of eating, and that consumption of hypercaloric diets and obesity disrupt these processes. Collectively, this evidence indicates that diet-induced obesity may be caused and/or maintained, at least in part, by a vicious cycle wherein excess intake disrupts hippocampal functioning, which further increases intake. This perspective may advance our understanding of how the brain controls eating, the neural mechanisms that contribute to eating-related disorders, and identify how to treat diet-induced obesity.
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Affiliation(s)
- Marise B. Parent
- Neuroscience Institute & Department of Psychology, Georgia State University, Box 5030, Atlanta, GA 30303-5030, United States,Corresponding author: Marise B. Parent, , Georgia State University, PO Box 5030, Atlanta, GA 30303-5030, USA. Fax: 404-413-5446
| | - Suzanne Higgs
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, BI5 2TT, United Kingdom
| | - Lucy G. Cheke
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB United Kingdom
| | - Scott E Kanoski
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, 90089-0371, United States
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17
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Knez R, Stevanovic D, Fernell E, Gillberg C. Orexin/Hypocretin System Dysfunction in ESSENCE (Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations). Neuropsychiatr Dis Treat 2022; 18:2683-2702. [PMID: 36411777 PMCID: PMC9675327 DOI: 10.2147/ndt.s358373] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 07/28/2022] [Indexed: 11/17/2022] Open
Abstract
Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations (ESSENCE) is an umbrella term covering a wide range of neurodevelopmental difficulties and disorders. Thus, ESSENCE includes attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other neurodevelopmental disorders (NDDs) and difficulties, with a variety of symptoms in cognitive, motor, sensory, social, arousal, regulatory, emotional, and behavioral developmental domains, frequently co-occurring and likely having partly common neurobiological substrates. The ESSENCE concept is a clinical paradigm that promotes organizing NDDs in everyday clinical practice according to their coexistence, symptom dimensions overlapping, and treatment possibilities. Despite increased knowledge regarding NDDs, the neurobiological mechanisms that underlie them and other ESSENCE-related problems, are not well understood. With its wide range of neural circuits and interactions with numerous neurotransmitters, the orexin/hypocretin system (Orx-S) is possibly associated with a variety of neurocognitive, psychobiological, neuroendocrine, and physiological functions and behaviors. Dysfunction of Orx-S has been implicated in various psychiatric and neurological disorders. This article provides an overview of Orx-S dysfunctions' possible involvement in the development, presentation, and maintenance of ESSENCE. We provide a focused review of current research evidence linking orexin neuropeptides with specific clinical NDDs symptoms, mostly in ADHD and ASD, within the Research Domain Criteria (RDoC) framework. We propose that Orx-S dysfunction might have an important role in some of these neurodevelopmental symptom domains, such as arousal, wakefulness, sleep, motor and sensory processing, mood and emotional regulation, fear processing, reward, feeding, attention, executive functions, and sociability. Our perspective is presented from a clinical point of view. Further, more thorough systematic reviews are needed as well as planning of extensive new research into the Orx-S's role in ESSENCE, especially considering RDoC elements.
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Affiliation(s)
- Rajna Knez
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Pediatrics, Skaraborg Hospital, Skövde, Sweden.,School of Health Sciences, University of Skövde, Skövde, Sweden
| | - Dejan Stevanovic
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Elisabeth Fernell
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Christopher Gillberg
- Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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18
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Vaseghi S, Zarrabian S, Haghparast A. Reviewing the role of the orexinergic system and stressors in modulating mood and reward-related behaviors. Neurosci Biobehav Rev 2021; 133:104516. [PMID: 34973302 DOI: 10.1016/j.neubiorev.2021.104516] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 01/22/2023]
Abstract
In this review study, we aimed to introduce the orexinergic system as an important signaling pathway involved in a variety of cognitive functions such as memory, motivation, and reward-related behaviors. This study focused on the role of orexinergic system in modulating reward-related behavior, with or without the presence of stressors. Cross-talk between the reward system and orexinergic signaling was also investigated, especially orexinergic signaling in the ventral tegmental area (VTA), the nucleus accumbens (NAc), and the hippocampus. Furthermore, we discussed the role of the orexinergic system in modulating mood states and mental illnesses such as depression, anxiety, panic, and posttraumatic stress disorder (PTSD). Here, we narrowed down our focus on the orexinergic signaling in three brain regions: the VTA, NAc, and the hippocampus (CA1 region and dentate gyrus) for their prominent role in reward-related behaviors and memory. It was concluded that the orexinergic system is critically involved in reward-related behavior and significantly alters stress responses and stress-related psychiatric and mood disorders.
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Affiliation(s)
- Salar Vaseghi
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran
| | - Shahram Zarrabian
- Department of Anatomical Sciences & Cognitive Neuroscience, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.
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19
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Lehner M, Skórzewska A, Wisłowska-Stanek A. Sex-Related Predisposition to Post-Traumatic Stress Disorder Development-The Role of Neuropeptides. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:314. [PMID: 35010574 PMCID: PMC8750761 DOI: 10.3390/ijerph19010314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/21/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
Post-traumatic stress disorder (PTSD) is characterized by re-experiencing a traumatic event, avoidance, negative alterations in cognitions and mood, hyperarousal, and severe functional impairment. Women have a two times higher risk of developing PTSD than men. The neurobiological basis for the sex-specific predisposition to PTSD might be related to differences in the functions of stress-responsive systems due to the interaction between gonadal hormones and stress peptides such as corticotropin-releasing factor (CRF), orexin, oxytocin, and neuropeptide Y. Additionally, in phases where estrogens levels are low, the risk of developing or exacerbating PTSD is higher. Most studies have revealed several essential sex differences in CRF function. They include genetic factors, e.g., the CRF promoter contains estrogen response elements. Importantly, sex-related differences are responsible for different predispositions to PTSD and diverse treatment responses. Fear extinction (the process responsible for the effectiveness of behavioral therapy for PTSD) in women during periods of high endogenous estradiol levels (the primary form of estrogens) is reportedly more effective than in periods of low endogenous estradiol. In this review, we present the roles of selected neuropeptides in the sex-related predisposition to PTSD development.
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Affiliation(s)
- Małgorzata Lehner
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957 Warsaw, Poland; (M.L.); (A.S.)
| | - Anna Skórzewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957 Warsaw, Poland; (M.L.); (A.S.)
| | - Aleksandra Wisłowska-Stanek
- Centre for Preclinical Research and Technology (CEPT), Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, 1B Banacha Street, 02-097 Warsaw, Poland
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20
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Gao F, Liu T, Tuo M, Chi S. The role of orexin in Alzheimer disease: From sleep-wake disturbance to therapeutic target. Neurosci Lett 2021; 765:136247. [PMID: 34530113 DOI: 10.1016/j.neulet.2021.136247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/01/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
Accumulating evidence has shown that sleep disturbance is a common symptom in Alzheimer's disease (AD), which is regarded as a modifiable risk factor for AD. Orexin is a key modulator of the sleep-wake cycle and has been found to be dysregulated in AD patients. The increased orexin in cerebrospinal fluid (CSF) is associated with decreased sleep efficiency and REM sleep, as well as cognitive impairment in AD patients. The orexin system has profuse projections to brain regions that are implicated in arousal and cognition and has been found to participate in the progression of AD pathology. Conversely the orexin receptor antagonists are able to consolidate sleep and reduce AD pathology. Therefore, improved understanding of the mechanisms linking orexin system, sleep disturbance and AD could make orexin receptor antagonists a promising target for the prevention or treatment of AD.
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Affiliation(s)
- Fan Gao
- Department of Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Tao Liu
- Department of Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Miao Tuo
- Department of Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Song Chi
- Department of Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China.
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21
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Zhao S, Wang S, Li H, Guo J, Li J, Wang D, Zhang X, Yin L, Li R, Li A, Li H, Fan Z, Yang Q, Zhong H, Dong H. Activation of Orexinergic Neurons Inhibits the Anesthetic Effect of Desflurane on Consciousness State via Paraventricular Thalamic Nucleus in Rats. Anesth Analg 2021; 133:781-793. [PMID: 34403389 DOI: 10.1213/ane.0000000000005651] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Orexin, a neuropeptide derived from the perifornical area of the hypothalamus (PeFLH), promotes the recovery of propofol, isoflurane, and sevoflurane anesthesias, without influencing the induction time. However, whether the orexinergic system also plays a similar role in desflurane anesthesia, which is widely applied in clinical practice owing to its most rapid onset and offset time among all volatile anesthetics, has not yet been studied. In the present study, we explored the effect of the orexinergic system on the consciousness state induced by desflurane anesthesia. METHODS The c-Fos staining was used to observe the activity changes of orexinergic neurons in the PeFLH and their efferent projection regions under desflurane anesthesia. Chemogenetic and optogenetic techniques were applied to compare the effect of PeFLH orexinergic neurons on the induction, emergence, and maintenance states between desflurane and isoflurane anesthesias. Orexinergic terminals in the paraventricular thalamic nucleus (PVT) were manipulated with pharmacologic, chemogenetic, and optogenetic techniques to assess the effect of orexinergic circuitry on desflurane anesthesia. RESULTS Desflurane anesthesia inhibited the activity of orexinergic neurons in the PeFLH, as well as the neuronal activity in PVT, basal forebrain, dorsal raphe nucleus, and ventral tegmental area, as demonstrated by c-Fos staining. Activation of PeFLH orexinergic neurons prolonged the induction time and accelerated emergence from desflurane anesthesia but only influenced the emergence in isoflurane anesthesia, as demonstrated by chemogenetic and pharmacologic techniques. Meanwhile, optical activation of orexinergic neurons exhibited a long-lasting inhibitory effect on burst-suppression ratio (BSR) under desflurane anesthesia, and the effect may be contributed by the orexinergic PeFLH-PVT circuitry. The orexin-2 receptor (OX2R), but not orexin-1 receptor (OX1R), in the PVT, which had been inhibited most significantly by desflurane, mediated the proemergence effect of desflurane anesthesia. CONCLUSIONS We discovered, for the first time, that orexinergic neurons in the PeFLH could not only influence the maintenance and emergence from isoflurane and desflurane anesthesias but also affect the induction under desflurane anesthesia. Furthermore, this specific effect is probably mediated by orexinergic PeFLH-PVT circuitry, especially OX2Rs in the PVT.
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Affiliation(s)
- Shiyi Zhao
- From the Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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22
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Delorme J, Wang L, Kuhn FR, Kodoth V, Ma J, Martinez JD, Raven F, Toth BA, Balendran V, Vega Medina A, Jiang S, Aton SJ. Sleep loss drives acetylcholine- and somatostatin interneuron-mediated gating of hippocampal activity to inhibit memory consolidation. Proc Natl Acad Sci U S A 2021; 118:e2019318118. [PMID: 34344824 PMCID: PMC8364159 DOI: 10.1073/pnas.2019318118] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Sleep loss disrupts consolidation of hippocampus-dependent memory. To characterize effects of learning and sleep loss, we quantified activity-dependent phosphorylation of ribosomal protein S6 (pS6) across the dorsal hippocampus of mice. We find that pS6 is enhanced in dentate gyrus (DG) following single-trial contextual fear conditioning (CFC) but is reduced throughout the hippocampus after brief sleep deprivation (SD; which disrupts contextual fear memory [CFM] consolidation). To characterize neuronal populations affected by SD, we used translating ribosome affinity purification sequencing to identify cell type-specific transcripts on pS6 ribosomes (pS6-TRAP). Cell type-specific enrichment analysis revealed that SD selectively activated hippocampal somatostatin-expressing (Sst+) interneurons and cholinergic and orexinergic hippocampal inputs. To understand the functional consequences of SD-elevated Sst+ interneuron activity, we used pharmacogenetics to activate or inhibit hippocampal Sst+ interneurons or cholinergic input from the medial septum. The activation of either cell population was sufficient to disrupt sleep-dependent CFM consolidation by gating activity in granule cells. The inhibition of either cell population during sleep promoted CFM consolidation and increased S6 phosphorylation among DG granule cells, suggesting their disinhibition by these manipulations. The inhibition of either population across post-CFC SD was insufficient to fully rescue CFM deficits, suggesting that additional features of sleeping brain activity are required for consolidation. Together, our data suggest that state-dependent gating of DG activity may be mediated by cholinergic input and local Sst+ interneurons. This mechanism could act as a sleep loss-driven inhibitory gate on hippocampal information processing.
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Affiliation(s)
- James Delorme
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Lijing Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Femke Roig Kuhn
- Program in Behavioural and Cognitive Neurosciences, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Varna Kodoth
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Jingqun Ma
- Bioinformatics Core, Biomedical Research Core Facilities, University of Michigan, Ann Arbor, MI 48019
| | - Jessy D Martinez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Frank Raven
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Brandon A Toth
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Vinodh Balendran
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Alexis Vega Medina
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Sha Jiang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019
| | - Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019;
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23
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Zhang D, Perrey DA, Decker AM, Langston TL, Mavanji V, Harris DL, Kotz CM, Zhang Y. Discovery of Arylsulfonamides as Dual Orexin Receptor Agonists. J Med Chem 2021; 64:8806-8825. [PMID: 34101446 DOI: 10.1021/acs.jmedchem.1c00841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Loss of orexin-producing neurons results in narcolepsy with cataplexy, and orexin agonists have been shown to increase wakefulness and alleviate narcolepsy symptoms in animal models. Several OX2R agonists have been reported but with little or no activity at OX1R. We conducted structure-activity relationship studies on the OX2R agonist YNT-185 (2) and discovered dual agonists such as RTOXA-43 (40) with EC50's of 24 nM at both OX2R and OX1R. Computational modeling studies based on the agonist-bound OX2R cryogenic electron microscopy structures showed that 40 bound in the same binding pocket and interactions of the pyridylmethyl group of 40 with OX1R may have contributed to its high OX1R potency. Intraperitoneal injection of 40 increased time awake, decreased time asleep, and increased sleep/wake consolidation in 12-month old mice. This work provides a promising dual small molecule agonist and supports development of orexin agonists as potential treatments for orexin-deficient disorders such as narcolepsy.
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Affiliation(s)
- Dehui Zhang
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - David A Perrey
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Ann M Decker
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Tiffany L Langston
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Vijayakumar Mavanji
- Research Service, Veterans Affairs Health Care System, Minneapolis, Minnesota 55417, United States
| | - Danni L Harris
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Catherine M Kotz
- Research Service, Veterans Affairs Health Care System, Minneapolis, Minnesota 55417, United States.,Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Geriatric, Research, Education and Clinical Center, Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417, United States
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
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24
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Zhu J, Tang S, Zhao D, Zeng Z, Mo H, Hu K. Orexin A improves the cognitive impairment induced by chronic intermittent hypoxia in mice. Brain Res Bull 2021; 173:203-210. [PMID: 34051297 DOI: 10.1016/j.brainresbull.2021.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/09/2021] [Accepted: 05/24/2021] [Indexed: 01/04/2023]
Abstract
The orexin neuron in lateral hypothalamus (LH) was involved in the regulation of sleep-wake cycle. However, the effect of orexin A (OXA) on cognitive impairment resulting from diverse diseases remains controversial. In this study, we investigated the effect of OXA on cognitive impairment induced by chronic intermittent hypoxia (CIH) in mice. Adult (10 weeks old) male C57BL/6 mice were randomly divided into the following four groups: normoxia control (NC)+normal saline (NS), NC + OXA, CIH + NS and CIH + OXA group. Following the CIH mice models establishment, OXA was injected into the right lateral ventricles of mice by a micro-injection system. Water maze test was used to assess spatial memory abilities of the mice. The expression of OXA and c-Fos in LH were analyzed by immunofluorescence staining. Apoptotic cell death and oxidative stress in hippocampus were evaluated using multiple methods including TUNEL, western blot and biochemical analysis. Behavioral tests revealed that CIH significantly increased the escape latency and time of arriving platform, of which were markedly decreased by OXA treatment. Similarly, the CIH + NS group was worse than NC + NS group in terms of the number of platform crossing and time in the target quadrant, of which were also significantly improved by OXA treatment. The number of OXA + neuron in LH was decreased, but the percentage of c-Fos+/OXA + neuron in LH was remarkably increased by CIH. Furthermore, we found that micro-injection of OXA attenuated CIH-induced apoptotic cell death and oxidative stress in the hippocampus. Our results suggested that OXA might improve cognitive impairment induced by CIH through inhibiting hippocampal apoptosis and oxidative stress.
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Affiliation(s)
- Jing Zhu
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China; Department of Respiratory and Critical Care Medicine, the People's Hospital of China Three Gorges University, Yichang, Hubei, China
| | - Si Tang
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Dong Zhao
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Zhaofu Zeng
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Huaheng Mo
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Ke Hu
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
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25
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Intranasal insulin and orexins to treat age-related cognitive decline. Physiol Behav 2021; 234:113370. [PMID: 33621561 DOI: 10.1016/j.physbeh.2021.113370] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 02/19/2021] [Indexed: 02/06/2023]
Abstract
The intranasal (IN) administration of neuropeptides, such as insulin and orexins, has been suggested as a treatment strategy for age-related cognitive decline (ARCD). Because dysfunctional neuropeptide signaling is an observed characteristic of ARCD, it has been suggested that IN delivery of insulin and/or orexins may restore endogenous peptide signaling and thereby preserve cognition. IN administration is particularly alluring as it is a relatively non-invasive method that directly targets peptides to the brain. Several laboratories have examined the behavioral effects of IN insulin in young, aged, and cognitively impaired rodents and humans. These studies demonstrated improved performance on various cognitive tasks following IN insulin administration. Fewer laboratories have assessed the effects of IN orexins; however, this peptide also holds promise as an effective treatment for ARCD through the activation of the cholinergic system and/or the reduction of neuroinflammation. Here, we provide a brief overview of the advantages of IN administration and the delivery pathway, then summarize the current literature on IN insulin and orexins. Additional preclinical studies will be useful to ultimately uncover the mechanisms underlying the pro-cognitive effects of IN insulin and orexins, whereas future clinical studies will aid in the determination of the most efficacious dose and dosing paradigm. Eventually, IN insulin and/or orexin administration may be a widely used treatment strategy in the clinic for ARCD.
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26
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Stanojlovic M, Pallais JP, Kotz CM. Inhibition of Orexin/Hypocretin Neurons Ameliorates Elevated Physical Activity and Energy Expenditure in the A53T Mouse Model of Parkinson's Disease. Int J Mol Sci 2021; 22:E795. [PMID: 33466831 PMCID: PMC7830608 DOI: 10.3390/ijms22020795] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 11/17/2022] Open
Abstract
Aside from the classical motor symptoms, Parkinson's disease also has various non-classical symptoms. Interestingly, orexin neurons, involved in the regulation of exploratory locomotion, spontaneous physical activity, and energy expenditure, are affected in Parkinson's. In this study, we hypothesized that Parkinson's-disease-associated pathology affects orexin neurons and therefore impairs functions they regulate. To test this, we used a transgenic animal model of Parkinson's, the A53T mouse. We measured body composition, exploratory locomotion, spontaneous physical activity, and energy expenditure. Further, we assessed alpha-synuclein accumulation, inflammation, and astrogliosis. Finally, we hypothesized that chemogenetic inhibition of orexin neurons would ameliorate observed impairments in the A53T mice. We showed that aging in A53T mice was accompanied by reductions in fat mass and increases in exploratory locomotion, spontaneous physical activity, and energy expenditure. We detected the presence of alpha-synuclein accumulations in orexin neurons, increased astrogliosis, and microglial activation. Moreover, loss of inhibitory pre-synaptic terminals and a reduced number of orexin cells were observed in A53T mice. As hypothesized, this chemogenetic intervention mitigated the behavioral disturbances induced by Parkinson's disease pathology. This study implicates the involvement of orexin in early Parkinson's-disease-associated impairment of hypothalamic-regulated physiological functions and highlights the importance of orexin neurons in Parkinson's disease symptomology.
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Affiliation(s)
- Milos Stanojlovic
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine, Bünteweg 17, 30559 Hannover, Germany
| | - Jean Pierre Pallais
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, 321 Church St SE, Minneapolis, MN 55455, USA; (J.P.P.); (C.M.K.)
| | - Catherine M. Kotz
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, 321 Church St SE, Minneapolis, MN 55455, USA; (J.P.P.); (C.M.K.)
- Minneapolis VA Health Care System, GRECC, 1 Veterans Dr, Minneapolis, MN 55417, USA
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27
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Abstract
Twenty-two years after their discovery, the hypocretins (Hcrts), also known as orexins, are two of the most studied peptidergic systems, involved in myriad physiological systems that range from sleep, arousal, motivation, homeostatic regulation, fear, anxiety and learning. A causal relationship between activity of Hcrt and arousal stability was established shortly after their discovery and have led to the development of a new class of drugs to treat insomnia. In this review we discuss the many faces of the Hcrt system and examine recent findings that implicate decreased Hcrt function in the pathogenesis of a number of neuropsychiatric conditions. We also discuss future therapeutic strategies to replace or enhance Hcrt function as a treatment option for these neuropsychiatric conditions.
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Affiliation(s)
- Erica Seigneur
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
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28
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Phospholipase Cβ3 in the hippocampus may mediate impairment of memory by long-term blockade of orexin 1 receptors assessed by the Morris water maze. Life Sci 2020; 257:118046. [PMID: 32622948 DOI: 10.1016/j.lfs.2020.118046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/19/2020] [Accepted: 06/30/2020] [Indexed: 11/23/2022]
Abstract
Orexin-A is an endogenous peptide with receptors throughout the brain. According to some recent research, learning and memory are affected by the central administration of orexin; however, no study so far has investigated the long-term inhibition of the orexinergic system. The present study has evaluated the effect of pretraining administration of orexin 1 receptor (OXR1) antagonist, SB-334867, on the acquisition of memory. The Morris water maze (MWM) task was used for training and trial purposes in all groups. Memory performance was analyzed by measuring escape latency, traveled distance, and time spent in the target quadrant. Moreover, the effect of SB-334867 on phospholipase Cβ3 (PLCβ3) levels in the CA1 region of hippocampus slices was examined. Hippocampus slices were prepared using an immunohistochemistry (IHC) approach. SB-334867 (20 mg/kg) increased escape latency in SB-treated rats compared to SB-vehicle group (P < 0.01). SB-treated rats spent less time in the target quadrant compared to the SB-vehicle group (P < 0.001). Distance traveled in the target quadrant was significantly more in SB-treated rats compared to the SB-vehicle group (P < 0.001). Furthermore, SB-334867 decreased PLCβ3 levels in the CA1 of the hippocampus (P < 0.01 and P < 0.05, respectively). Put together, our results suggest that the long-term inhibition of OXR1 plays a prominent role in spatial learning and memory, probably by attenuating PLCβ3 in CA1 neurons.
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29
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Burdakov D, Peleg-Raibstein D. The hypothalamus as a primary coordinator of memory updating. Physiol Behav 2020; 223:112988. [DOI: 10.1016/j.physbeh.2020.112988] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/05/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022]
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30
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Orexins role in neurodegenerative diseases: From pathogenesis to treatment. Pharmacol Biochem Behav 2020; 194:172929. [PMID: 32315694 DOI: 10.1016/j.pbb.2020.172929] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 12/12/2022]
Abstract
Orexin is a neurotransmitter that mainly regulates sleep/wake cycle. In addition to its sleep cycle regulatory role, it is involved in regulation of attention, energy homeostasis, neurogenesis and cognition. Several evidences has shown the involvement of orexin in narcolepsy, but there are also growing evidences that shows the disturbance in orexin system in neurodegenerative diseases including Alzheimer's, Parkinson's, Epilepsy, Huntington's diseases and Amyotrophic lateral sclerosis. Pathogenesis and clinical symptoms of these disorders can be partly attributed from orexin system imbalance. However, there are controversial reports on the exact relationship between orexin and these neurodegenerative diseases. Therefore, the aim of this review is to summarize the current evidences regarding the role of orexin in these neurodegenerative diseases.
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31
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Salehabadi S, Abrari K, Elahdadi Salmani M, Nasiri M, Lashkarbolouki T. Investigating the role of the amygdala orexin receptor 1 in memory acquisition and extinction in a rat model of PTSD. Behav Brain Res 2020; 384:112455. [DOI: 10.1016/j.bbr.2019.112455] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/17/2019] [Accepted: 12/26/2019] [Indexed: 11/15/2022]
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32
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Orexin-1 receptor blockade differentially affects spatial and visual discrimination memory facilitation by intracranial self-stimulation. Neurobiol Learn Mem 2020; 169:107188. [PMID: 32061874 DOI: 10.1016/j.nlm.2020.107188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 02/06/2020] [Accepted: 02/11/2020] [Indexed: 01/07/2023]
Abstract
Intracranial self-stimulation (ICSS) of the medial forebrain bundle is an effective treatment to facilitate memory. Performance in both explicit and implicit memory tasks has been improved by ICSS, and this treatment has even been capable of recovering loss of memory function due to lesions or old age. Several neurochemical systems have been studied in regard to their role in ICSS effects on memory, however the possible involvement of the orexinergic system in this facilitation has yet to be explored. The present study aims to examine the relationship between the OX1R and the facilitative effects of ICSS on two different types of memory tasks, both carried out in the Morris Water Maze: spatial and visual discrimination. Results show that the OX1R blockade, by intraventricular administration of SB-334867, partially negates the facilitating effect of ICSS on spatial memory, whereas it hinders ICSS facilitation of the discrimination task. However, ICSS treatment was capable of compensating for the severe detrimental effects of OX1R blockade on both memory paradigms. These results suggest different levels of involvement of the orexinergic system in the facilitation of memory by ICSS, depending on the memory task.
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33
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Fakhoury M, Salman I, Najjar W, Merhej G, Lawand N. The Lateral Hypothalamus: An Uncharted Territory for Processing Peripheral Neurogenic Inflammation. Front Neurosci 2020; 14:101. [PMID: 32116534 PMCID: PMC7029733 DOI: 10.3389/fnins.2020.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/24/2020] [Indexed: 12/20/2022] Open
Abstract
The roles of the hypothalamus and particularly the lateral hypothalamus (LH) in the regulation of inflammation and pain have been widely studied. The LH consists of a parasympathetic area that has connections with all the major parts of the brain. It controls the autonomic nervous system (ANS), regulates feeding behavior and wakeful cycles, and is a part of the reward system. In addition, it contains different types of neurons, most importantly the orexin neurons. These neurons, though few in number, perform critical functions such as inhibiting pain transmission and interfering with the reward system, feeding behavior and the hypothalamic pituitary axis (HPA). Recent evidence has identified a new role for orexin neurons in the modulation of pain transmission associated with several inflammatory diseases, including rheumatoid arthritis and ulcerative colitis. Here, we review recent findings on the various physiological functions of the LH with special emphasis on the orexin/receptor system and its role in mediating inflammatory pain.
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Affiliation(s)
- Marc Fakhoury
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Israa Salman
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Wassim Najjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - George Merhej
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nada Lawand
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Department of Neurology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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34
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Depletion of hypothalamic hypocretin/orexin neurons correlates with impaired memory in a Parkinson's disease animal model. Exp Neurol 2020; 323:113110. [DOI: 10.1016/j.expneurol.2019.113110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/18/2019] [Accepted: 11/07/2019] [Indexed: 12/12/2022]
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35
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Stanojlovic M, Pallais JP, Lee MK, Kotz CM. Pharmacological and chemogenetic orexin/hypocretin intervention ameliorates Hipp-dependent memory impairment in the A53T mice model of Parkinson's disease. Mol Brain 2019; 12:87. [PMID: 31666100 PMCID: PMC6822428 DOI: 10.1186/s13041-019-0514-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/18/2019] [Indexed: 01/01/2023] Open
Abstract
Parkinson's disease (PD), classically defined as a progressive motor disorder accompanied with dopaminergic neuron loss and presence of Lewy bodies, is the second most common neurodegenerative disease. PD also has various non-classical symptoms, including cognitive impairments. In addition, inflammation and astrogliosis are recognized as an integral part of PD pathology. The hippocampus (Hipp) is a brain region involved in cognition and memory, and the neuropeptide orexin has been shown to enhance learning and memory. Previous studies show impairments in Hipp-dependent memory in a transgenic mouse model of Parkinson's disease (A53T mice), and we hypothesized that increasing orexin tone will reverse this. To test this, we subjected 3, 5, and 7-month old A53T mice to a Barnes maze and a contextual object recognition test to determine Hipp dependent memory. Inflammation and astrogliosis markers in the Hipp were assessed by immuno-fluorescence densitometry. The data show that early cognitive impairment is coupled with an increase in expression of inflammatory and astrogliosis markers. Next, in two separate experiments, mice were given intra-hippocampal injections of orexin or chemogenetic viral injections of an orexin neuron specific Designer Receptor Exclusively Activated by Designer Drug (DREADD). For the pharmacological approach mice were intracranially treated with orexin A, whereas the chemogenetic approach utilized clozapine N-oxide (CNO). Both pharmacological orexin A intervention as well as chemogenetic activation of orexin neurons ameliorated Hipp-dependent early memory impairment observed in A53T mice. This study implicates orexin in PD-associated cognitive impairment and suggests that exogenous orexin treatment and/or manipulation of endogenous orexin levels may be a potential strategy for addressing early cognitive loss in PD.
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Affiliation(s)
- Milos Stanojlovic
- Integrative Biology and Physiology, University of Minnesota, 2231 6th St SE, Minneapolis, MN, 55455, USA.
| | - Jean Pierre Pallais
- Integrative Biology and Physiology, University of Minnesota, 2231 6th St SE, Minneapolis, MN, 55455, USA
| | - Michael K Lee
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience (ITN), University of Minnesota, Minneapolis, MN, USA
| | - Catherine M Kotz
- Integrative Biology and Physiology, University of Minnesota, 2231 6th St SE, Minneapolis, MN, 55455, USA
- Minneapolis VA Health Care System, GRECC, Minneapolis, MN, USA
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36
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Wang Y, Chen AQ, Xue Y, Liu MF, Liu C, Liu YH, Pan YP, Diao HL, Chen L. Orexins alleviate motor deficits via increasing firing activity of pallidal neurons in a mouse model of Parkinson's disease. Am J Physiol Cell Physiol 2019; 317:C800-C812. [PMID: 31365289 DOI: 10.1152/ajpcell.00125.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Orexin is a peptide neurotransmitter released in the globus pallidus. Morphological evidence reveals that both orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R) exist in the globus pallidus. Here we showed that bilateral microinjection of both orexin-A and orexin-B into the globus pallidus alleviated motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian mice. Further in vivo extracellular single-unit recording revealed that the basal spontaneous firing rate of the globus pallidus neurons in MPTP parkinsonian mice was slower than that of normal mice. Application of orexin-A or orexin-B significantly increased the spontaneous firing rate of pallidal neurons. The influx of Ca2+ through the L-type Ca2+ channel is the major mechanism involved in orexin-induced excitation in the globus pallidus. Orexin-A-induced increase in firing rate of pallidal neurons in MPTP parkinsonian mice was stronger than that of normal mice. Orexin-A exerted both electrophysiological and behavioral effects mainly via OX1R, and orexin-B exerted the effects via OX2R. Endogenous orexins modulated the excitability of globus pallidus neurons mainly through OX1R. The present behavioral and electrophysiological results suggest that orexins ameliorate parkinsonian motor deficits through increasing the spontaneous firing of globus pallidus neurons.
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Affiliation(s)
- Ying Wang
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - An-Qi Chen
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yan Xue
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Mei-Fang Liu
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Cui Liu
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yun-Hai Liu
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yi-Peng Pan
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Hui-Ling Diao
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Lei Chen
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
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37
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Stanojlovic M, Pallais JP, Kotz CM. Chemogenetic Modulation of Orexin Neurons Reverses Changes in Anxiety and Locomotor Activity in the A53T Mouse Model of Parkinson's Disease. Front Neurosci 2019; 13:702. [PMID: 31417337 PMCID: PMC6682689 DOI: 10.3389/fnins.2019.00702] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/21/2019] [Indexed: 01/02/2023] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disease. PD symptomology is recognized as heterogeneous and in addition to motor function decline includes cognitive, mood, sleep, and metabolic disorders. Previous studies showed early reductions in anxiety and locomotion in the A53T mice model of PD. Since inflammation and astrogliosis are an integral part of PD pathology and impair proper neuronal function, we were keen to investigate if behavioral changes in A53T mice are accompanied by increased inflammation and astrogliosis in the hippocampus (Hipp) and motor cortex (mCtx) brain regions involved in the regulation of anxiety and locomotion, respectively. To test this, we used 3-, 5-, and 7-month-old A53T mice to examine anxiety-like behavior, locomotion, and expression of inflammation and astrogliosis markers in the Hipp and mCtx. Further, we examined the presence of alpha-synuclein accumulation in orexin neurons and orexin neuronal loss. The data show early reductions in anxiety-like behavior as well as increased locomotor activity, which was accompanied by inflammation and astrogliosis in the Hipp and mCtx. Due to the persistence of the orexin neuron population in A53T mice and the involvement of orexin in anxiety and locomotor regulation, we hypothesized that chemogenetic modulation of orexin neurons would reverse the observed reductions in anxiety-like behavior and the increases in locomotor activity in these animals. We showed that chemogenetic activation of orexin neurons in A53T mice restores anxiety-like behavior back to control levels without affecting locomotor activity, whereas the inhibition of orexin neurons reverses the elevated locomotor activity without any effects on anxiety-like behavior. This study exemplifies the complex role of orexin neurons in this model of PD and demonstrates the novel finding that changes in locomotor and anxiety-like behavior are accompanied by inflammation and astrogliosis. Together, these data suggest that the orexin system may play a significant role in early and late stages of PD.
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Affiliation(s)
- Milos Stanojlovic
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Jean Pierre Pallais
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States
| | - Catherine M Kotz
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States.,Minneapolis VA Health Care System, Geriatric Research, Education and Clinical Center, Minneapolis, MN, United States
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38
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Stanojlovic M, Pallais Yllescas JP, Vijayakumar A, Kotz C. Early Sociability and Social Memory Impairment in the A53T Mouse Model of Parkinson's Disease Are Ameliorated by Chemogenetic Modulation of Orexin Neuron Activity. Mol Neurobiol 2019; 56:8435-8450. [PMID: 31250383 DOI: 10.1007/s12035-019-01682-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/14/2019] [Indexed: 02/08/2023]
Abstract
Parkinson's disease (PD) is a multi-layered progressive neurodegenerative disease. Signature motor system impairments are accompanied by a variety of other symptoms such as mood, sleep, metabolic, and cognitive disorders. Interestingly, social cognition impairments can be observed from the earliest stages of the disease, prior to the onset of the motor symptoms. In this study, we investigated age-related reductions in sociability and social memory in the A53T mouse model of PD. Since inflammation and astrogliosis are an integral part of PD pathology and impair proper neuronal function, we examined astrogliosis and inflammation markers and parvalbumin expression in medial pre-frontal cortex (mPFC), part of the brain responsible for social cognition regulation. Finally, we used DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) for the stimulation and inhibition of orexin neuronal activity to modulate sociability and social memory in A53T mice. We observed that social cognition impairment in A53T mice is accompanied by an increase in astrogliosis and inflammation markers, in addition to loss of parvalbumin neurons and inhibitory pre-synaptic terminals in the mPFC. Moreover, DREADD-induced activation of orexin neurons restores social cognition in the A53T mouse model of PD. SIGNIFICANCE STATEMENT: Social cognition is severely affected in the early stages of Parkinson's disease. In this study, we identified the A53T mouse as a model of social cognitive impairment in PD. Observed alterations in sociability and social memory are accompanied by loss of parvalbumin positive neurons and loss of inhibitory input to mPFC. Stimulating orexin neurons using a chemogenetic approach (DREADDs) ameliorated social cognitive impairment. This study identifies a role for orexin neurons in social cognition in PD and suggests potential therapeutic targets for PD-related social cognition impairments.
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Affiliation(s)
- Milos Stanojlovic
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.
| | | | - Aarthi Vijayakumar
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Catherine Kotz
- Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.,GRECC, Minneapolis VA Health Care System, Minneapolis, MN, USA
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Stanojlovic M, Pallais Yllescas JP, Mavanji V, Kotz C. Chemogenetic activation of orexin/hypocretin neurons ameliorates aging-induced changes in behavior and energy expenditure. Am J Physiol Regul Integr Comp Physiol 2019; 316:R571-R583. [PMID: 30726119 PMCID: PMC6589608 DOI: 10.1152/ajpregu.00383.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023]
Abstract
Aging affects numerous physiological processes, as well as behavior. A large number of these processes are regulated, at least partially, by hypothalamic orexin neurons, and orexin tone may decrease with normal aging. In this study, we hypothesized that designer receptors exclusively activated by designer drugs (DREADD) stimulation of orexin neuronal activity will ameliorate the effect of aging on behavioral and metabolic alterations in young and middle-aged mice. DREADD targeting was achieved by stereotaxic injection of AAV vectors (AAV2-hSyn-DIO-hM3D(Gq)-mCherry) into the lateral hypothalamus of 5- and 12-mo old orexin-cre female mice and was confirmed by immunohistochemistry (IHC) analysis of orexin A and mCherry expression. After recovery, animals were subjected to a behavioral test battery consisting of the elevated plus maze (EPM), open field (OFT), and novel object recognition tests (NORT) to assess effects of aging on anxiety-like behavior, general locomotion, and working memory. A comprehensive laboratory animal monitoring system (CLAMS) was used to measure spontaneous physical activity (SPA) and energy expenditure (EE). The results indicate that activation of orexin neurons mitigates aging-induced reductions in anxiety-like behavior in middle-aged mice (P < 0.005) and increases locomotion in both young and middle-aged mice (P < 0.05). Activation of orexin neurons increases SPA (P < 0.01) and EE (P < 0.005) in middle-aged mice, restoring the levels to that observed in young animals. Results from this study identify orexin neurons as potential therapeutic targets for age-related impairments in cognitive and anxiety-related behavior, and energy balance.
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Affiliation(s)
- Milos Stanojlovic
- Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota
| | | | - Vijaya Mavanji
- Minneapolis Veterans Affairs Health Care System, Geriatric Research Education and Clinical Center , Minneapolis, Minnesota
| | - Catherine Kotz
- Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota
- Minneapolis Veterans Affairs Health Care System, Geriatric Research Education and Clinical Center , Minneapolis, Minnesota
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Suarez AN, Noble EE, Kanoski SE. Regulation of Memory Function by Feeding-Relevant Biological Systems: Following the Breadcrumbs to the Hippocampus. Front Mol Neurosci 2019; 12:101. [PMID: 31057368 PMCID: PMC6482164 DOI: 10.3389/fnmol.2019.00101] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/03/2019] [Indexed: 12/15/2022] Open
Abstract
The hippocampus (HPC) controls fundamental learning and memory processes, including memory for visuospatial navigation (spatial memory) and flexible memory for facts and autobiographical events (declarative memory). Emerging evidence reveals that hippocampal-dependent memory function is regulated by various peripheral biological systems that are traditionally known for their roles in appetite and body weight regulation. Here, we argue that these effects are consistent with a framework that it is evolutionarily advantageous to encode and recall critical features surrounding feeding behavior, including the spatial location of a food source, social factors, post-absorptive processing, and other episodic elements of a meal. We review evidence that gut-to-brain communication from the vagus nerve and from feeding-relevant endocrine systems, including ghrelin, insulin, leptin, and glucagon-like peptide-1 (GLP-1), promote hippocampal-dependent spatial and declarative memory via neurotrophic and neurogenic mechanisms. The collective literature reviewed herein supports a model in which various stages of feeding behavior and hippocampal-dependent memory function are closely linked.
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Affiliation(s)
- Andrea N Suarez
- Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Emily E Noble
- Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Scott E Kanoski
- Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
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Wang P, Wang M, Zhang L, Zhong S, Jiang W, Wang Z, Sun C, Zhang S, Liu Z. Functional characterization of an orexin neuropeptide in amphioxus reveals an ancient origin of orexin/orexin receptor system in chordate. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1655-1669. [PMID: 30945108 DOI: 10.1007/s11427-018-9421-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 10/10/2018] [Indexed: 01/09/2023]
Abstract
Amphioxus belongs to the subphylum cephalochordata, an extant representative of the most basal chordates, whose regulation of endocrine system remains ambiguous. Here we clearly demonstrated the existence of a functional orexin neuropeptide in amphioxus, which is able to interact with orexin receptor, activate both PKC and PKA pathways, decrease leptin expression, and stimulate lipogenesis. We also showed the transcription level of amphioxus orexin was affected by fasting or temperature, indicating a role of this gene in the regulation of energy balance. In addition, the expression of the amphioxus orexin was detected at cerebral vesicle, which has been proposed to be a homolog of the vertebrate brain. These data collectively suggest that a functional orexin neuropeptide has already emerged in amphioxus, which provide insights into the evolutionary origin of orexin in chordate and the functional homology between the cerebral vesicle and vertebrate brain.
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Affiliation(s)
- Peng Wang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Meng Wang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Liping Zhang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Shenjie Zhong
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Wanyue Jiang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Ziyue Wang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Chen Sun
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Shicui Zhang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China.
| | - Zhenhui Liu
- Institute of Evolution & Marine Biodiversity, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China.
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Couvineau A, Voisin T, Nicole P, Gratio V, Abad C, Tan YV. Orexins as Novel Therapeutic Targets in Inflammatory and Neurodegenerative Diseases. Front Endocrinol (Lausanne) 2019; 10:709. [PMID: 31695678 PMCID: PMC6817618 DOI: 10.3389/fendo.2019.00709] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 02/05/2023] Open
Abstract
Orexins [orexin-A (OXA) and orexin-B (OXB)] are two isoforms of neuropeptides produced by the hypothalamus. The main biological actions of orexins, focused on the central nervous system, are to control the sleep/wake process, appetite and feeding, energy homeostasis, drug addiction, and cognitive processes. These effects are mediated by two G protein-coupled receptor (GPCR) subtypes named OX1R and OX2R. In accordance with the synergic and dynamic relationship between the nervous and immune systems, orexins also have neuroprotective and immuno-regulatory (i.e., anti-inflammatory) properties. The present review gathers recent data demonstrating that orexins may have a therapeutic potential in several pathologies with an immune component including multiple sclerosis, Alzheimer's disease, narcolepsy, obesity, intestinal bowel diseases, septic shock, and cancers.
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Affiliation(s)
- Alain Couvineau
- INSERM UMR1149/Inflammation Research Center (CRI), Team “From Inflammation to Cancer in Digestive Diseases” Labeled by “la Ligue Nationale Contre le Cancer”, University of Paris, Paris, France
- *Correspondence: Alain Couvineau
| | - Thierry Voisin
- INSERM UMR1149/Inflammation Research Center (CRI), Team “From Inflammation to Cancer in Digestive Diseases” Labeled by “la Ligue Nationale Contre le Cancer”, University of Paris, Paris, France
| | - Pascal Nicole
- INSERM UMR1149/Inflammation Research Center (CRI), Team “From Inflammation to Cancer in Digestive Diseases” Labeled by “la Ligue Nationale Contre le Cancer”, University of Paris, Paris, France
| | - Valérie Gratio
- INSERM UMR1149/Inflammation Research Center (CRI), Team “From Inflammation to Cancer in Digestive Diseases” Labeled by “la Ligue Nationale Contre le Cancer”, University of Paris, Paris, France
| | - Catalina Abad
- University of Rouen Normandy, INSERM U1234 PANTHER, IRIB, Rouen, France
| | - Yossan-Var Tan
- University of Rouen Normandy, INSERM U1234 PANTHER, IRIB, Rouen, France
- Yossan-Var Tan
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D'Souza MS. Brain and Cognition for Addiction Medicine: From Prevention to Recovery Neural Substrates for Treatment of Psychostimulant-Induced Cognitive Deficits. Front Psychiatry 2019; 10:509. [PMID: 31396113 PMCID: PMC6667748 DOI: 10.3389/fpsyt.2019.00509] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 06/28/2019] [Indexed: 01/10/2023] Open
Abstract
Addiction to psychostimulants like cocaine, methamphetamine, and nicotine poses a continuing medical and social challenge both in the United States and all over the world. Despite a desire to quit drug use, return to drug use after a period of abstinence is a common problem among individuals dependent on psychostimulants. Recovery for psychostimulant drug-dependent individuals is particularly challenging because psychostimulant drugs induce significant changes in brain regions associated with cognitive functions leading to cognitive deficits. These cognitive deficits include impairments in learning/memory, poor decision making, and impaired control of behavioral output. Importantly, these drug-induced cognitive deficits often impact adherence to addiction treatment programs and predispose abstinent addicts to drug use relapse. Additionally, these cognitive deficits impact effective social and professional rehabilitation of abstinent addicts. The goal of this paper is to review neural substrates based on animal studies that could be pharmacologically targeted to reverse psychostimulant-induced cognitive deficits such as impulsivity and impairment in learning and memory. Further, the review will discuss neural substrates that could be used to facilitate extinction learning and thus reduce emotional and behavioral responses to drug-associated cues. Moreover, the review will discuss some non-pharmacological approaches that could be used either alone or in combination with pharmacological compounds to treat the above-mentioned cognitive deficits. Psychostimulant addiction treatment, which includes treatment for cognitive deficits, will help promote abstinence and allow for better rehabilitation and integration of abstinent individuals into society.
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Affiliation(s)
- Manoranjan S D'Souza
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, Ada, OH, United States
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Liu MF, Xue Y, Liu C, Liu YH, Diao HL, Wang Y, Pan YP, Chen L. Orexin-A Exerts Neuroprotective Effects via OX1R in Parkinson's Disease. Front Neurosci 2018. [PMID: 30524223 DOI: 10.3389/fnins.2018.00835.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder characterized by progressive and selective death of dopaminergic neurons. Orexin-A is involved in many biological effects of the body. It has been reported that orexin-A has protective effects in cellular models of PD. However, little is known about the protective effects of orexin-A in animal parkinsonian models and the cellular mechanism has not yet been fully clarified. The aim of this study was to evaluate the effects of orexin-A in MPTP mice model of PD as well as the possible neuroprotective mechanisms of orexin-A on dopaminergic neurons. The results from animal experiments demonstrated that orexin-A attenuated the loss of dopaminergic neurons and the decrease of tyrosine hydroxylase (TH) expression in the substantia nigra, normalized the striatal dopaminergic fibers, and prevented the depletion of dopamine and its metabolites in the striatum. MPTP-treated mice showed cognitive impairments accompanied with significant motor deficiency. Orexin-A improved MPTP-induced impairments in both motor activity and spatial memory. Importantly, orexin-A increased the protein level of brain-derived neurotrophic factor (BDNF) in dopaminergic neurons of the substantia nigra. Furthermore, the protective effects of orexin-A on MPTP parkinsonian mice could be blocked by orexinergic receptor 1 (OX1R) antagonist, SB334867. In another set of experiments with SH-SY5Y dopaminergic cells, orexin-A significantly induced the expression of BDNF in a dose and time-dependent manner. The upregulation of BDNF is mainly concerned with PI3K and PKC signaling pathways via OX1R. The present study demonstrated that orexin-A exerted neuroprotective effects on MPTP parkinsonian mice, which may imply orexin-A as a potential therapeutic target for PD.
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Affiliation(s)
- Mei-Fang Liu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China.,College of Pharmacy, Jining Medical University, Rizhao, China
| | - Yan Xue
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Cui Liu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Yun-Hai Liu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Hui-Ling Diao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Ying Wang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Yi-Peng Pan
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Lei Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
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Duffy CM, Hofmeister JJ, Nixon JP, Butterick TA. High fat diet increases cognitive decline and neuroinflammation in a model of orexin loss. Neurobiol Learn Mem 2018; 157:41-47. [PMID: 30471346 DOI: 10.1016/j.nlm.2018.11.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/26/2018] [Accepted: 11/16/2018] [Indexed: 12/23/2022]
Abstract
Midlife obesity is a risk factor for cognitive decline and is associated with the earlier onset of Alzheimer's disease (AD). Diets high in saturated fat potentiate the onset of obesity, microglial activation, and neuroinflammation. Signaling deficiencies in the hypothalamic peptide orexin and/or orexin fiber loss are linked to neurodegeneration, cognitive impairment, and neuroinflammation. Prior studies show that orexin is neuroprotective, suppresses neuroinflammation, and that treatment with orexin improves cognitive processes in orexin/ataxin-3 (O/A3) mice, a transgenic mouse model of orexin neurodegeneration. Our overall hypothesis is that loss of orexin contributes to high fat diet (HFD)-induced hippocampal neuroinflammation and cognitive decline. To examine this, we tested male O/A3 mice (7-8 mo. of age) in a two-way active avoidance (TWAA) hippocampus-dependent memory task. We tested whether (1) orexin loss impaired cognitive function; (2) HFD worsened cognitive impairment; and (3) HFD increased microglial activation and neuroinflammation. O/A3 mice showed significant impairments in TWAA task learning vs. wild type (WT) mice (increased escapes p < 0.05, reduced avoidances p < 0.0001). Mice were then placed on HFD (45% total fat, 31.4% saturated fat) or remained on normal chow (NC; 4% total fat and 1% saturated fat), and TWAA was retested at 2 and 4 weeks. Learning impairment was evident at both 2 and 4 weeks in O/A3 mice fed HFD for following diet exposure vs. WT mice on normal chow or HFD (increased escapes, reduced avoidances p < 0.05). Additionally, O/A3 mice had increased gene expression of the microglial activation marker Iba-1 (measured via qRT-PCR, p < 0.001). Further characterization of the microglial immune response genes in hippocampal tissue revealed a significant increase in CX3 chemokine receptor 1 (CX3CR1), tumor necrosis factor-alpha (TNF-α) and the mitochondria-associated enzyme immune responsive gene-1 (Irg1). Collectively, our results indicate that orexin loss impairs memory, and that HFD accelerates hippocampus-dependent learning deficits and the onset of neuroinflammation.
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Affiliation(s)
- C M Duffy
- Minneapolis Veterans Affairs Health Care System, Minneapolis, MN, United States; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, United States
| | - J J Hofmeister
- Minneapolis Veterans Affairs Health Care System, Minneapolis, MN, United States; Minneapolis Center for Veterans Research and Education, Minneapolis, MN, United States
| | - J P Nixon
- Minneapolis Veterans Affairs Health Care System, Minneapolis, MN, United States; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, United States; Minneapolis Center for Veterans Research and Education, Minneapolis, MN, United States
| | - T A Butterick
- Minneapolis Veterans Affairs Health Care System, Minneapolis, MN, United States; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, United States; Minneapolis Center for Veterans Research and Education, Minneapolis, MN, United States.
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Liu MF, Xue Y, Liu C, Liu YH, Diao HL, Wang Y, Pan YP, Chen L. Orexin-A Exerts Neuroprotective Effects via OX1R in Parkinson's Disease. Front Neurosci 2018; 12:835. [PMID: 30524223 PMCID: PMC6262320 DOI: 10.3389/fnins.2018.00835] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/26/2018] [Indexed: 12/22/2022] Open
Abstract
Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by progressive and selective death of dopaminergic neurons. Orexin-A is involved in many biological effects of the body. It has been reported that orexin-A has protective effects in cellular models of PD. However, little is known about the protective effects of orexin-A in animal parkinsonian models and the cellular mechanism has not yet been fully clarified. The aim of this study was to evaluate the effects of orexin-A in MPTP mice model of PD as well as the possible neuroprotective mechanisms of orexin-A on dopaminergic neurons. The results from animal experiments demonstrated that orexin-A attenuated the loss of dopaminergic neurons and the decrease of tyrosine hydroxylase (TH) expression in the substantia nigra, normalized the striatal dopaminergic fibers, and prevented the depletion of dopamine and its metabolites in the striatum. MPTP-treated mice showed cognitive impairments accompanied with significant motor deficiency. Orexin-A improved MPTP-induced impairments in both motor activity and spatial memory. Importantly, orexin-A increased the protein level of brain-derived neurotrophic factor (BDNF) in dopaminergic neurons of the substantia nigra. Furthermore, the protective effects of orexin-A on MPTP parkinsonian mice could be blocked by orexinergic receptor 1 (OX1R) antagonist, SB334867. In another set of experiments with SH-SY5Y dopaminergic cells, orexin-A significantly induced the expression of BDNF in a dose and time-dependent manner. The upregulation of BDNF is mainly concerned with PI3K and PKC signaling pathways via OX1R. The present study demonstrated that orexin-A exerted neuroprotective effects on MPTP parkinsonian mice, which may imply orexin-A as a potential therapeutic target for PD.
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Affiliation(s)
- Mei-Fang Liu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China.,College of Pharmacy, Jining Medical University, Rizhao, China
| | - Yan Xue
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Cui Liu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Yun-Hai Liu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Hui-Ling Diao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Ying Wang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Yi-Peng Pan
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Lei Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
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Activation of orexin system facilitates anesthesia emergence and pain control. Proc Natl Acad Sci U S A 2018; 115:E10740-E10747. [PMID: 30348769 DOI: 10.1073/pnas.1808622115] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Orexin (also known as hypocretin) neurons in the hypothalamus play an essential role in sleep-wake control, feeding, reward, and energy homeostasis. The likelihood of anesthesia and sleep sharing common pathways notwithstanding, it is important to understand the processes underlying emergence from anesthesia. In this study, we investigated the role of the orexin system in anesthesia emergence, by specifically activating orexin neurons utilizing the designer receptors exclusively activated by designer drugs (DREADD) chemogenetic approach. With injection of adeno-associated virus into the orexin-Cre transgenic mouse brain, we expressed the DREADD receptor hM3Dq specifically in orexin neurons and applied the hM3Dq ligand clozapine to activate orexin neurons. We monitored orexin neuronal activities by c-Fos staining and whole-cell patch-clamp recording and examined the consequence of orexin neuronal activation via EEG recording. Our results revealed that the orexin-DREADD mice with activated orexin neurons emerged from anesthesia with significantly shorter latency than the control mice. As an indication of reduced pain sensitivity, these orexin-DREADD mice took longer to respond to the 55 °C thermal stimuli in the hot plate test and exhibited significantly less frequent licking of the formalin-injected paw in the formalin test. Our study suggests that approaches to activate the orexin system can be beneficial in postoperative recovery.
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Azeez IA, Del Gallo F, Cristino L, Bentivoglio M. Daily Fluctuation of Orexin Neuron Activity and Wiring: The Challenge of "Chronoconnectivity". Front Pharmacol 2018; 9:1061. [PMID: 30319410 PMCID: PMC6167434 DOI: 10.3389/fphar.2018.01061] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/03/2018] [Indexed: 12/12/2022] Open
Abstract
In the heterogeneous hub represented by the lateral hypothalamus, neurons containing the orexin/hypocretin peptides play a key role in vigilance state transitions and wakefulness stability, energy homeostasis, and other functions relevant for motivated behaviors. Orexin neurons, which project widely to the neuraxis, are innervated by multiple extra- and intra-hypothalamic sources. A key property of the adaptive capacity of orexin neurons is represented by daily variations of activity, which is highest in the period of the animal’s activity and wakefulness. These sets of data are here reviewed. They concern the discharge profile during the sleep/wake cycle, spontaneous Fos induction, peptide synthesis and release reflected by immunostaining intensity and peptide levels in the cerebrospinal fluid as well as postsynaptic effects. At the synaptic level, adaptive capacity of orexin neurons subserved by remodeling of excitatory and inhibitory inputs has been shown in response to changes in the nutritional status and prolonged wakefulness. The present review wishes to highlight that synaptic plasticity in the wiring of orexin neurons also occurs in unperturbed conditions and could account for diurnal variations of orexin neuron activity. Data in zebrafish larvae have shown rhythmic changes in the density of inhibitory innervation of orexin dendrites in relation to vigilance states. Recent findings in mice have indicated a diurnal reorganization of the excitatory/inhibitory balance in the perisomatic innervation of orexin neurons. Taken together these sets of data point to “chronoconnectivity,” i.e., a synaptic rearrangement of inputs to orexin neurons over the course of the day in relation to sleep and wake states. This opens questions on the underlying circadian and homeostatic regulation and on the involved players at synaptic level, which could implicate dual transmitters, cytoskeletal rearrangements, hormonal regulation, as well as surrounding glial cells and extracellular matrix. Furthermore, the question arises of a “chronoconnectivity” in the wiring of other neuronal cell groups of the sleep-wake-regulatory network, many of which are characterized by variations of their firing rate during vigilance states.
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Affiliation(s)
- Idris A Azeez
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Federico Del Gallo
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | | | - Marina Bentivoglio
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,National Institute of Neuroscience, Verona Unit, Verona, Italy
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Nevárez N, de Lecea L. Recent advances in understanding the roles of hypocretin/orexin in arousal, affect, and motivation. F1000Res 2018; 7. [PMID: 30254737 PMCID: PMC6127742 DOI: 10.12688/f1000research.15097.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/24/2018] [Indexed: 12/11/2022] Open
Abstract
The hypocretins (Hcrts) are two alternatively spliced neuropeptides (Hcrt1/Ox-A and Hcrt2/Ox-B) that are synthesized exclusively in the hypothalamus. Data collected in the 20 years since their discovery have supported the view that the Hcrts play a broad role in the control of arousal with a particularly important role in the maintenance of wakefulness and sleep-to-wake transitions. While this latter point has received an overwhelming amount of research attention, a growing literature has begun to broaden our understanding of the many diverse roles that the Hcrts play in physiology and behavior. Here, we review recent advances in the neurobiology of Hcrt in three sections. We begin by surveying findings on Hcrt function within normal sleep/wake states as well as situations of aberrant sleep (that is, narcolepsy). In the second section, we discuss research establishing a role for Hcrt in mood and affect (that is, anxiety, stress, and motivation). Finally, in the third section, we briefly discuss future directions for the field and place an emphasis on analytical modeling of Hcrt neural activity. We hope that the data discussed here provide a broad overview of recent progress in the field and make clear the diversity of roles played by these neuromodulators.
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Affiliation(s)
- Natalie Nevárez
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, California, USA
| | - Luis de Lecea
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, California, USA
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Abstract
Purpose of Review The aim of this review was to summarize collected data on the role of orexin and orexin neurons in the control of sleep and blood pressure. Recent Findings Although orexins (hypocretins) have been known for only 20 years, an impressive amount of data is now available regarding their physiological role. Hypothalamic orexin neurons are responsible for the control of food intake and energy expenditure, motivation, circadian rhythm of sleep and wake, memory, cognitive functions, and the cardiovascular system. Multiple studies show that orexinergic stimulation results in increased blood pressure and heart rate and that this effect may be efficiently attenuated by orexinergic antagonism. Increased activity of orexinergic neurons is also observed in animal models of hypertension. Summary Pharmacological intervention in the orexinergic system is now one of the therapeutic possibilities in insomnia. Although the role of orexin in the control of blood pressure is well described, we are still lacking clinical evidence that this is a possibility for a new approach in the treatment of cardiovascular diseases.
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Affiliation(s)
- Mariusz Sieminski
- Department of Emergency Medicine, Medical University of Gdansk, Smoluchowskiego 17, 80-235, Gdansk, Poland.
| | - Jacek Szypenbejl
- Department of Emergency Medicine, Medical University of Gdansk, Smoluchowskiego 17, 80-235, Gdansk, Poland
| | - Eemil Partinen
- Department of Neurology, University of Helsinki, Helsinki, Finland
- Vitalmed Helsinki Sleep Clinic, Helsinki, Finland
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