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Piri F, Salmani ME, Sepehri H. Improvement of autistic-like behaviors in adult rats prenatally exposed to valproic acid through early suppression of orexin receptor. Ann Med Surg (Lond) 2024; 86:166-171. [PMID: 38222731 PMCID: PMC10783284 DOI: 10.1097/ms9.0000000000000788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/28/2023] [Indexed: 01/16/2024] Open
Abstract
Introduction Autism spectrum disorder (ASD) is a disabling psychiatric disease characterized by impairments in communication and social skills. The pathophysiology of autism is complex and not fully known. Considering the incidence of sleep disorders in individuals with ASD and the important role of orexin in sleep, it is possible to hypothesize that an alteration of the orexinergic system could be implicated in the pathogenesis of autism symptoms. The present study was conducted to investigate the effect of suvorexant [dual orexin receptor antagonists (DORAs)] on autism-like behavior in prenatally valproic acid (VPA)-exposed rats]. Methods Wistar female rats were administered VPA [600 mg/kg, intraperitoneally (i.p.)] or normal saline (10 ml/kg, i.p.; vehicle control) on gestational day 12.5. Thirty-two male offspring were divided into four groups: Control, VPA, Suvorexant+VPA, and VPA+Risperidone. The pups were given suvorexant [20 ml/kg, by mouth/orally (p.o.)] or risperidone (1 ml/kg, p.o.) daily from postnatal day (PND) (40-54). The offspring were tested for repetitive behaviors and cognitive ability with a Y-maze task on PND 55, and social interaction was assessed by play behavior in the open field on PND 56. And anxiety with using the three-chamber social assay on PND 56. Results In the Y-maze apparatus, spontaneous alteration significantly decreased in the prenatal VPA-treated rats compared to control rats showing autistic-like behavior, and 2-week suvorexant increased the alternation, indicating the beneficial effect of suvorexant. Prenatal treatment with VPA, impaired play behavior (sniffing, grooming, and darting), and increased anxiety-related behavior. Suvorexant treatment attenuated the problems in male offspring's social behavior. Conclusion Our results showed that suvorexant improved ASD-associated behaviors in the VPA-treated rats, and the orexinergic system may be associated with the pathogenesis of autism symptoms.
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Affiliation(s)
| | | | - Hamid Sepehri
- Neuroscience Research Center, Department of Physiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
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Bonifazi A, Del Bello F, Giorgioni G, Piergentili A, Saab E, Botticelli L, Cifani C, Micioni Di Bonaventura E, Micioni Di Bonaventura MV, Quaglia W. Targeting orexin receptors: Recent advances in the development of subtype selective or dual ligands for the treatment of neuropsychiatric disorders. Med Res Rev 2023; 43:1607-1667. [PMID: 37036052 DOI: 10.1002/med.21959] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/08/2023] [Accepted: 03/28/2023] [Indexed: 04/11/2023]
Abstract
Orexin-A and orexin-B, also named hypocretin-1 and hypocretin-2, are two hypothalamic neuropeptides highly conserved across mammalian species. Their effects are mediated by two distinct G protein-coupled receptors, namely orexin receptor type 1 (OX1-R) and type 2 (OX2-R), which share 64% amino acid identity. Given the wide expression of OX-Rs in different central nervous system and peripheral areas and the several pathophysiological functions in which they are involved, including sleep-wake cycle regulation (mainly mediated by OX2-R), emotion, panic-like behaviors, anxiety/stress, food intake, and energy homeostasis (mainly mediated by OX1-R), both subtypes represent targets of interest for many structure-activity relationship (SAR) campaigns carried out by pharmaceutical companies and academies. However, before 2017 the research was predominantly directed towards dual-orexin ligands, and limited chemotypes were investigated. Analytical characterizations, including resolved structures for both OX1-R and OX2-R in complex with agonists and antagonists, have improved the understanding of the molecular basis of receptor recognition and are assets for medicinal chemists in the design of subtype-selective ligands. This review is focused on the medicinal chemistry aspects of small molecules acting as dual or subtype selective OX1-R/OX2-R agonists and antagonists belonging to different chemotypes and developed in the last years, including radiolabeled OX-R ligands for molecular imaging. Moreover, the pharmacological effects of the most studied ligands in different neuropsychiatric diseases, such as sleep, mood, substance use, and eating disorders, as well as pain, have been discussed. Poly-pharmacology applications and multitarget ligands have also been considered.
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Affiliation(s)
- Alessandro Bonifazi
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States
| | - Fabio Del Bello
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Camerino, Italy
| | - Gianfabio Giorgioni
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Camerino, Italy
| | | | - Elizabeth Saab
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States
| | - Luca Botticelli
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | | | | | - Wilma Quaglia
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Camerino, Italy
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Orexin Receptor Antagonists in the Treatment of Depression: A Leading Article Summarising Pre-clinical and Clinical Studies. CNS Drugs 2023; 37:1-12. [PMID: 36436175 DOI: 10.1007/s40263-022-00974-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/02/2022] [Indexed: 11/28/2022]
Abstract
The orexin (hypocretin) system comprises two neuropeptides (orexin-A and orexin-B) and two G-protein coupled receptors (the orexin type 1 and the orexin type 2 receptor). The system regulates several biological functions including appetite, the sleep-wake cycle, the stress response, and motivation and reward processing. Dysfunction of the orexin system has been implicated in the pathophysiology of depression in human and animal studies, although the exact nature of this dysfunction remains unclear. Orexin receptor antagonists (ORAs) are a class of compounds developed for the treatment of insomnia and have demonstrated efficacy in this area. Three dual orexin receptor antagonists (DORAs) have received licences for treatment of primary insomnia and some ORAs have since been investigated as potential treatments for major depressive disorder (MDD). In this leading article, we summarise the existing literature on use of ORAs in depression, in pre-clinical and clinical studies. In rodent models of depression, investigated ORAs have included the DORA almorexant and TCS1102, the selective orexin 1 receptor antagonists SB334867 and SB674042 and the selective orexin 2 receptor antagonists LSN2424100, MK-1064 and TCS-OX2-29. These pre-clinical studies suggest a possible antidepressant effect of systemic DORA treatment, however the evidence from selective ORAs is conflicting. To date, four published RCTs (one with the DORA filorexant and three with the selective orexin 2 receptor antagonist seltorexant), have compared an ORA with placebo in the treatment of MDD. Only one of these demonstrated a statistically significant difference relative to placebo.
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Hsu CW, Wang S. Changes in the Orexin System in Rats Exhibiting Learned Helplessness Behaviors. Brain Sci 2021; 11:brainsci11121634. [PMID: 34942932 PMCID: PMC8699801 DOI: 10.3390/brainsci11121634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/16/2022] Open
Abstract
Orexin-A (OX-A) and orexin-B (OX-B) are neuropeptides produced in the hypothalamus. Preclinical and clinical studies suggest that depression and anxiety are associated with the orexin system. In the current study, we used the learned helplessness (LH) animal model of depression to identify rats displaying LH behaviors (LH rats) and those that did not (No-LH rats). We compared the number of orexin-containing neurons in the hypothalamus of LH, No-LH, and control rats. Orexin peptides, orexin receptor 1 (OXR1) and 2 (OXR2) in brain areas involved in major depression and serum OX-A and corticosterone (CORT) concentrations were quantified and compared between rat groups. We found that LH and No-LH rats displayed higher serum OX-A concentrations compared with control rats. Comparison between LH and No-LH rats revealed that No-LH rats had significantly higher OX-A levels in the brain, more OX-A neurons, and more OX-A neuron activation. LH rats had more OX-B neurons and more OX-B neuron activation. Orexin peptides and receptors in the brain areas involved in major depression exhibited different patterns in LH and NoLH rats. Our findings revealed that activation of OX-A neurons could promote resilient behaviors under stressful situations and OX-A and OX-B neuropeptides exhibit dissimilar functions in LH behaviors.
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Sen ZD, Danyeli LV, Woelfer M, Lamers F, Wagner G, Sobanski T, Walter M. Linking atypical depression and insulin resistance-related disorders via low-grade chronic inflammation: Integrating the phenotypic, molecular and neuroanatomical dimensions. Brain Behav Immun 2021; 93:335-352. [PMID: 33359233 DOI: 10.1016/j.bbi.2020.12.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
Insulin resistance (IR) and related disorders, such as T2DM, increase the risk of major depressive disorder (MDD) and vice versa. Current evidence indicates that psychological stress and overeating can induce chronic low-grade inflammation that can interfere with glutamate metabolism in MDD as well as insulin signaling, particularly in the atypical subtype. Here we first review the interactive role of inflammatory processes in the development of MDD, IR and related metabolic disorders. Next, we describe the role of the anterior cingulate cortex in the pathophysiology of MDD and IR-related disorders. Furthermore, we outline how specific clinical features of atypical depression, such as hyperphagia, are more associated with inflammation and IR-related disorders. Finally, we examine the regional specificity of the effects of inflammation on the brain that show an overlap with the functional and morphometric brain patterns activated in MDD and IR-related disorders.
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Affiliation(s)
- Zümrüt Duygu Sen
- Department of Psychiatry and Psychotherapy, University Tuebingen, Calwerstraße 14, 72076 Tuebingen, Germany; Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany
| | - Lena Vera Danyeli
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Leipziger Str. 44, Building 65, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Marie Woelfer
- Clinical Affective Neuroimaging Laboratory (CANLAB), Leipziger Str. 44, Building 65, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Femke Lamers
- Department of Psychiatry, Amsterdam UMC, Vrije Universiteit, Oldenaller 1, 1081 HJ Amsterdam, the Netherlands
| | - Gerd Wagner
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany
| | - Thomas Sobanski
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, Thueringen-Kliniken "Georgius Agricola" GmbH, Rainweg 68, 07318 Saalfeld, Germany
| | - Martin Walter
- Department of Psychiatry and Psychotherapy, University Tuebingen, Calwerstraße 14, 72076 Tuebingen, Germany; Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Leipziger Str. 44, Building 65, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany.
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Wang D, Li A, Dong K, Li H, Guo Y, Zhang X, Cai M, Li H, Zhao G, Yang Q. Lateral hypothalamus orexinergic inputs to lateral habenula modulate maladaptation after social defeat stress. Neurobiol Stress 2021; 14:100298. [PMID: 33569507 PMCID: PMC7859368 DOI: 10.1016/j.ynstr.2021.100298] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/11/2021] [Accepted: 01/18/2021] [Indexed: 01/15/2023] Open
Abstract
Social stress, a common stressor, causes multiple forms of physical and mental dysfunction. Prolonged exposure to social stress is associated with a higher risk of psychological disorders, including anxiety disorders and major depressive disorder (MDD). The orexinergic system is involved in the regulation of multiple motivated behaviors. The current study examined the regulatory effect of orexinergic projections from the lateral hypothalamic area (LHA) to the lateral habenula (LHb) in depression- and anxiety-like behaviors after chronic social defeat stress. When mice were defeated during social interaction, both orexinergic neurons in the LHA and glutamatergic neurons in the LHb were strongly activated, as indicated by the FosTRAP strategy. Infusion of orexin in the LHb significantly alleviated social avoidance and depression-like behaviors induced by chronic social defeat stress. Administration of an orexin receptor 2 antagonist in the LHb further aggravated the depressive phenotype. Photoactivation of orexinergic cell bodies in the LHA or terminals in the LHb relieved anxiety-like behaviors induced by chronic social defeat stress. Collectively, we identified the antidepressant and anxiolytic effects of the circuit from LHA orexinergic neurons to the LHb in response to chronic social stress, providing new evidence of the antidepressant properties of LHA orexin circuits.
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Affiliation(s)
- Dan Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Ao Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Keyi Dong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Huihui Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Yongxin Guo
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Xinxin Zhang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Min Cai
- Department of Psychiatry, Xijing Hospital, Xi'an, Shaanxi, China
| | - Huiming Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Guangchao Zhao
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
| | - Qianzi Yang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Xi'an, Shaanxi, China
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Yaeger JD, Krupp KT, Gale JJ, Summers CH. Counterbalanced microcircuits for Orx1 and Orx2 regulation of stress reactivity. MEDICINE IN DRUG DISCOVERY 2020. [DOI: 10.1016/j.medidd.2020.100059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Khairuddin S, Aquili L, Heng BC, Hoo TLC, Wong KH, Lim LW. Dysregulation of the orexinergic system: A potential neuropeptide target in depression. Neurosci Biobehav Rev 2020; 118:384-396. [DOI: 10.1016/j.neubiorev.2020.07.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 07/19/2020] [Accepted: 07/31/2020] [Indexed: 12/20/2022]
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Pulver A, Kiive E, Kanarik M, Harro J. Association of orexin/hypocretin receptor gene (HCRTR1) with reward sensitivity, and interaction with gender. Brain Res 2020; 1746:147013. [PMID: 32652147 DOI: 10.1016/j.brainres.2020.147013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022]
Abstract
Orexins/hypocretins maintain wakefulness, increase appetite and participate in the coordination of stress response. We have recently provided evidence on the role of orexins in aggression, showing the association of the HCRTR1 genotype. (rs2271933 G > A; leading to amino acid substitution Ile408Val) with aggressiveness or breach of law in four independent cohorts. Aggressive behaviour can be reward driven and hence we have examined the association of HCRTR1 rs2271933 genotype with different aspects of reward sensitivity in the birth cohort representative Estonian Children Personality Behaviour and Health Study. HCRTR1 genotype was associated with reward sensitivity in a gender dependent manner. Male HCRTR1 A/A homozygotes had higher Openness to Rewards and the overall reward sensitivity score while, in contrast, female A/A homozygotes scored lower than G-allele carriers in Openness to Rewards. In the total sample, aggressiveness correlated positively with reward sensitivity, but this was on account of Insatiability by Reward. In contrast, the HCRTR1 A/A homozygotes had a positive association of aggressiveness and Openness to Rewards. Experience of stressful life events had a small but significant increasing effect on both aspects of reward sensitivity, and correlated in an anomalous way with reward sensitivity in the HCRTR1 A/A homozygotes. Conclusively, the higher aggressiveness of HCRTR1 A/A homozygotes appears based on a qualitative difference in sensitivity to rewards, in the form that suggests their lower ability to prevent responses to challenges being converted into overt aggression.
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Affiliation(s)
- Aleksander Pulver
- School of Natural Sciences and Health, Tallinn University, Narva Road 29, Astra Building, 10120 Tallinn, Estonia
| | - Evelyn Kiive
- Division of Special Education, Department of Education, University of Tartu, Näituse 2, 50409 Tartu, Estonia
| | - Margus Kanarik
- Division of Neuropsychopharmacology, Department of Psychology, University of Tartu, Ravila 14A Chemicum, 50411 Tartu, Estonia
| | - Jaanus Harro
- School of Natural Sciences and Health, Tallinn University, Narva Road 29, Astra Building, 10120 Tallinn, Estonia; Division of Neuropsychopharmacology, Department of Psychology, University of Tartu, Ravila 14A Chemicum, 50411 Tartu, Estonia.
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Swaab DF, Bao AM. Sex differences in stress-related disorders: Major depressive disorder, bipolar disorder, and posttraumatic stress disorder. HANDBOOK OF CLINICAL NEUROLOGY 2020; 175:335-358. [PMID: 33008536 DOI: 10.1016/b978-0-444-64123-6.00023-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Stress-related disorders, such as mood disorders and posttraumatic stress disorder (PTSD), are more common in women than in men. This sex difference is at least partly due to the organizing effect of sex steroids during intrauterine development, while activating or inhibiting effects of circulating sex hormones in the postnatal period and adulthood also play a role. Such effects result in structural and functional changes in neuronal networks, neurotransmitters, and neuropeptides, which make the arousal- and stress-related brain systems more vulnerable to environmental stressful events in women. Certain brainstem nuclei, the amygdala, habenula, prefrontal cortex, and hypothalamus are important hubs in the stress-related neuronal network. Various hypothalamic nuclei play a central role in this sexually dimorphic network. This concerns not only the hypothalamus-pituitary-adrenal axis (HPA-axis), which integrates the neuro-endocrine-immune responses to stress, but also other hypothalamic nuclei and systems that play a key role in the symptoms of mood disorders, such as disordered day-night rhythm, lack of reward feelings, disturbed eating and sex, and disturbed cognitive functions. The present chapter focuses on the structural and functional sex differences that are present in the stress-related brain systems in mood disorders and PTSD, placing the HPA-axis in the center. The individual differences in the vulnerability of the discussed systems, caused by genetic and epigenetic developmental factors warrant further research to develop tailor-made therapeutic strategies.
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Affiliation(s)
- Dick F Swaab
- Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands; Department of Neurobiology and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Zhejiang, China.
| | - Ai-Min Bao
- Department of Neurobiology and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Zhejiang, China; Key Laboratory of Mental Disorder Management, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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Adidharma W, Deats SP, Ikeno T, Lipton JW, Lonstein JS, Yan L. Orexinergic modulation of serotonin neurons in the dorsal raphe of a diurnal rodent, Arvicanthis niloticus. Horm Behav 2019; 116:104584. [PMID: 31445011 PMCID: PMC6885537 DOI: 10.1016/j.yhbeh.2019.104584] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/02/2019] [Accepted: 08/20/2019] [Indexed: 01/22/2023]
Abstract
The hypothalamic neuropeptide, orexin (or hypocretin), is implicated in numerous physiology and behavioral functions, including affective states such as depression and anxiety. The underlying mechanisms and neural circuits through which orexin modulates affective responses remain unclear. The objective of the present study was to test the hypothesis that the serotonin (5-HT) system of the dorsal raphe nucleus (DRN) is a downstream target through which orexin potentially manifests its role in affective states. Using a diurnal rodent, the Nile grass rat (Arvicanthis niloticus), we first characterized the expression of the orexin receptors OX1R and OX2R in the DRN using in situ hybridization. The results revealed distinct distributions of OX1R and OX2R mRNAs, with OX1R predominantly expressed in the dorsal and lateral wings of the DRN that are involved in affective processes, while OX2R was mostly found in the ventral DRN that is more involved in sensory-motor function. We next examined how the orexin-OX1R pathway regulates 5-HT in the DRN and some of its projection sites using a selective OX1R antagonist SB-334867 (10 mg/kg, i.p.). A single injection of SB-334867 decreased 5-HT-ir fibers within the anterior cingulate cortex (aCgC); five once-daily administrations of SB-334867 decreased 5-HT-ir not only in the aCgC but also in the DRN, oval bed nucleus of the stria terminalis (ovBNST), nucleus accumbens shell (NAcSh), and periaqueductal gray (PAG). HPLC analysis revealed that five once-daily administrations of SB-334867 did not affect 5-HT turnover to any of the five sites, although it increased the levels of both 5-HT and 5-HIAA in the NAcSh. These results together suggest that orexinergic modulation of DRN 5-HT neurons via OX1Rs may be one pathway through which orexin regulates mood and anxiety, as well as perhaps other neurobiological processes.
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Affiliation(s)
- Widya Adidharma
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - Sean P Deats
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - Tomoko Ikeno
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - Jack W Lipton
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA; Department of Translational Science & Molecular Medicine, Michigan State University, Grand Rapids, MI, 49503, USA
| | - Joseph S Lonstein
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - Lily Yan
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
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Harro J, Laas K, Eensoo D, Kurrikoff T, Sakala K, Vaht M, Parik J, Mäestu J, Veidebaum T. Orexin/hypocretin receptor gene (HCRTR1) variation is associated with aggressive behaviour. Neuropharmacology 2019; 156:107527. [DOI: 10.1016/j.neuropharm.2019.02.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/11/2019] [Accepted: 02/06/2019] [Indexed: 12/01/2022]
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Tsuchimine S, Hattori K, Ota M, Hidese S, Teraishi T, Sasayama D, Hori H, Noda T, Yoshida S, Yoshida F, Kunugi H. Reduced plasma orexin-A levels in patients with bipolar disorder. Neuropsychiatr Dis Treat 2019; 15:2221-2230. [PMID: 31496705 PMCID: PMC6689769 DOI: 10.2147/ndt.s209023] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 05/17/2019] [Indexed: 01/28/2023] Open
Abstract
PURPOSE Orexins are hypothalamic neuropeptides involved in the regulation of sleep, appetite and arousal. An altered orexin system has been implicated in the pathophysiology of psychiatric disorders. This study aimed to examine whether plasma orexin-A levels differ in patients with schizophrenia, major depressive disorder (MDD), or bipolar disorder (BD) compared to in healthy controls. We also examined the possible correlations between plasma orexin-A levels and clinical variables. PATIENTS AND METHODS All participants were Japanese. The sample consisted of 80 patients with schizophrenia (42 women, 52.5%; mean age 36.8 years), 80 patients with MDD (43 women, 53.8%; 43.7 years), and 40 patients with BD (24 women, 60%; 41.1 years), as well as 80 healthy controls (48 women, 60%; 47.0 years). Plasma orexin-A levels were quantified by an enzyme-linked immunosorbent assay. RESULTS Mean orexin-A levels were significantly different across the four diagnostic groups (F=4.09; df=3; p=0.007, η2 =0.06). In particular, the patients with BD showed significantly lower orexin-A levels than did the controls. When the median value of the control group (109.8 pg/ml) was set as a cut-off value, subjects whose orexin-A levels were below the cut-off were more common in all psychiatric groups (schizophrenia: 73.8%, x2 =9.56, df=1, p=0.003, OR=2.81, 95% CI: 1.45 to 5.45, d=0.57; MDD: 78.5%, x2 =14.02, df=1, p<0.001, OR=3.65, 95% CI: 1.82 to 7.29, d=0.72; BD: 87.5%, x2 =16.0, df=1, p<0.001, OR=7.00, 95% CI: 2.49 to 19.70, d=1.07). We found no association between plasma orexin-A levels and any clinical symptoms, depression severity, or medication doses. CONCLUSION Our results suggest that plasma orexin-A levels are reduced in patients with BD.
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Affiliation(s)
- Shoko Tsuchimine
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Kotaro Hattori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Miho Ota
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Shinsuke Hidese
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Toshiya Teraishi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Daimei Sasayama
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Hiroaki Hori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Takamasa Noda
- Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo187-8551, Japan
| | - Sumiko Yoshida
- Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo187-8551, Japan
| | - Fuyuko Yoshida
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo187-8502, Japan
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Shariq AS, Rosenblat JD, Alageel A, Mansur RB, Rong C, Ho RC, Ragguett RM, Pan Z, Brietzke E, McIntyre RS. Evaluating the role of orexins in the pathophysiology and treatment of depression: A comprehensive review. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:1-7. [PMID: 30576764 DOI: 10.1016/j.pnpbp.2018.12.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 10/27/2022]
Abstract
Orexins are neuropeptides that are postulated to play a central role in the regulation of the sleep-wake cycle, appetite, affect, and reward circuitry. The objectives of the current review are to comprehensively evaluate (1) the potential role of orexins in the pathophysiology of major depressive disorders (MDD) and (2) the orexin system as a novel target in the treatment of MDD. Dysfunction of the sleep-wake cycle is observed as a central feature of MDD pathophysiology. Orexin system disturbances produce sleep-wake dysfunction, as observed in MDD. Orexin antagonists have been shown to treat insomnia effectively without disrupting normal sleep architecture in both preclinical (e.g., animal models) and clinical studies. Orexin antagonists are generally safe, well-tolerated, and associated with an acceptable long-term adverse effect profile with relatively low propensity for tolerance or dependence. Orexin antagonists have also been shown to possess antidepressant-like properties in some animal models of MDD. Extant evidence indicates that orexin-modulating treatments exert pleiotropic effects on multiple neural systems implicated in the phenomenology of mood disorders and suggests orexins as a promising target for investigation and intervention in mood disorders. To date, no human clinical trials evaluating the antidepressant effects of orexin antagonists in MDD have been completed. Given the promising results from preclinical studies, clinical trials are merited to evaluate the antidepressant effects of orexin antagonists in MDD.
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Affiliation(s)
- Aisha S Shariq
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Department of Psychiatry, Texas Tech University Health Science Center, Paul L. Foster SOM, El Paso, TX 79905, USA
| | - Joshua D Rosenblat
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Department of Psychiatry, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Asem Alageel
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Department of Psychiatry, College of Medicine, Imam University, Riyadh, Saudi Arabia
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Department of Psychiatry, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Carola Rong
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Roger C Ho
- National University of Singapore, 119077, Singapore; National University of Hong Kong, 999077, Hong Kong
| | - Renee-Marie Ragguett
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Zihang Pan
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Elisa Brietzke
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Research Group in Molecular and Behavioral Neuroscience of Bipolar Disorder, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo 14021-001, Brazil
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON M5T 2S8, Canada; Department of Psychiatry, University of Toronto, Toronto, ON M5S 1A1, Canada; Department of Pharmacology, University of Toronto, Toronto, ON M5S 1A1, Canada; Brain and Cognition Discovery Foundation (BCDF), Toronto, ON M5T 2S8, Canada.
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16
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Cengiz M, Karaj V, Kocabasoğlu N, Gozubatik-Celik G, Dirican A, Bayoglu B. Orexin/hypocretin receptor, Orx1, gene variants are associated with major depressive disorder. Int J Psychiatry Clin Pract 2019; 23:114-121. [PMID: 30596528 DOI: 10.1080/13651501.2018.1551549] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Objective: Orexins (hypocretins) are neuropeptides expressed in hypothalamic neurons and have regulatory roles in feeding/drinking behaviours, endocrine functions and sleep/wakefulness state. Major depressive disorder (MDD) is a major mood disorder and neurotransmitter dysfunction in hypothalamic neurons may have roles in its formation. Hence, we conducted experiments to determine whether orexin receptor 1 and 2 (Orx1, Orx2) genes were associated with MDD development. Methods: Seventy-five MDD patients and 87 healthy controls were enrolled for the study. Genotyping was carried out with real-time polymerase chain reaction (RT-PCR). Hamilton Rating-Scale for Depression (HRSD) and Beck Depression Inventory (BDI) were utilized to evaluate depressive symptom severity. Results: A significant relation was found in genotype frequencies of Orx1 rs10914456 and rs2271933 variants between MDD patients and controls (p = .009, p = .006). Rs10914456 CC genotype increased MDD risk 3.57 times more than carrying other genotypes (p = .008, OR =3.57;95% CI: 1.39-9.14). However, no association was observed in Orx2 rs2653349 genotypes for MDD development (p > .05). Although statistically not significant, HRSD scores were diminished in MDD subjects carrying rs10914456 CC variants when compared with CT and TT variants (p = .069). Conclusion. This study suggests that, Orx1 rs10914456 and rs2271933 can be associated with MDD development. Hence, Orx1 rs10914456 variants may affect depressive symptom severity.
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Affiliation(s)
- Mujgan Cengiz
- a Department of Medical Biology, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Vilson Karaj
- b Department of Science, Institute of Forensic Sciences , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Nese Kocabasoğlu
- c Department of Psychiatry, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Gokcen Gozubatik-Celik
- d Department of Neurology, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Ahmet Dirican
- e Department of Biostatistics and Medical Informatics, Istanbul Medical Faculty , Istanbul University , Istanbul , Turkey
| | - Burcu Bayoglu
- a Department of Medical Biology, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
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17
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Li G, Zhang K, Wang L, Cao C, Fang R, Liu P, Luo S, Liberzon I. The preliminary investigation of orexigenic hormone gene polymorphisms on posttraumatic stress disorder symptoms. Psychoneuroendocrinology 2019; 100:131-136. [PMID: 30326460 DOI: 10.1016/j.psyneuen.2018.09.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/18/2018] [Accepted: 09/30/2018] [Indexed: 12/12/2022]
Abstract
Orexigenic hormones are a group of hormones that can up-regulate appetite. Current studies have shown that orexigenic hormones also play important roles in stress responses and may be implicated in regulation of fear memory. However, these conclusions lack evidence from human studies. In this study, we examined associations between orexigenic hormone genes and fear-related mental disorders by investigating main, G × E, and G × G effects of ghrelin and orexin gene single nucleotide polymorphisms (SNPs) on human posttraumatic stress disorder (PTSD) symptoms in 1134 Chinese earthquake survivors. SNPs Leu72Met of the GHRL gene (rs696217), Ile408Val of the HCRTR1 gene (rs2271933) and Val308Ile of the HCRTR2 gene (rs2653349) were genotyped. None of the SNPs showed significant main or G × E effects. However, a significant interaction effect between GHRL rs696217 and HCRTR1 rs2271933 was found to predict the PTSD Checklist (PCL-5) total score (P = 0.007). Further analysis revealed different interaction patterns in males and females. For females, the rs2271933 G allele was associated with an increased PCL-5 total score (B = 2.59, P = 0.024) when the rs696217 genotype TT/TG was present. For males, the rs696217 T allele is associated with an increased PCL-5 total score (B = 3.62, P = 0.040) when the rs2271933 genotype GG/GA was present. These current findings expand our knowledge of physiological function of the orexigenic hormone system, and suggest its involvement in development of fear-related mental disorders such as PTSD.
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Affiliation(s)
- Gen Li
- Laboratory for Traumatic Stress studies and Center for Genetics and BioMedical Informatics Research, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Kunlin Zhang
- Laboratory for Traumatic Stress studies and Center for Genetics and BioMedical Informatics Research, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
| | - Li Wang
- Laboratory for Traumatic Stress studies and Center for Genetics and BioMedical Informatics Research, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
| | - Chengqi Cao
- Laboratory for Traumatic Stress studies and Center for Genetics and BioMedical Informatics Research, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China; Shenzhen Key Laboratory of Affective and Social Cognitive Science, Shenzhen University, Shenzhen, China
| | - Ruojiao Fang
- Laboratory for Traumatic Stress studies and Center for Genetics and BioMedical Informatics Research, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Ping Liu
- People's Hospital of Deyang City, Deyang, Sichuan, China
| | - Shu Luo
- People's Hospital of Deyang City, Deyang, Sichuan, China
| | - Israel Liberzon
- Department of Psychiatry, University of Michigan and Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA; Department of Psychology, University of Michigan, Ann Arbor, MI, USA
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18
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Abstract
The neuropeptides orexins are important in regulating the neurobiological systems that respond to stressful stimuli. Furthermore, orexins are known to play a role many of the phenotypes associated with stress-related mental illness such as changes in cognition, sleep-wake states, and appetite. Interestingly, orexins are altered in stress-related psychiatric disorders such as Major Depressive Disorder and Anxiety Disorders. Thus, orexins may be a potential target for treatment of these disorders. In this review, we will focus on what is known about the role of orexins in acute and repeated stress, in stress-induced phenotypes relevant to psychiatric illness in preclinical models, and in stress-related psychiatric illness in humans. We will also briefly discuss how orexins may contribute to sex differences in the stress response and subsequent phenotypes relevant to mental health, as many stress-related psychiatric disorders are twice as prevalent in women.
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19
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Sargin D. The role of the orexin system in stress response. Neuropharmacology 2018; 154:68-78. [PMID: 30266600 DOI: 10.1016/j.neuropharm.2018.09.034] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/18/2018] [Accepted: 09/21/2018] [Indexed: 11/30/2022]
Abstract
Orexins are neuropeptides that are exclusively produced by hypothalamic neurons, which project throughout the entire brain. Orexin, also known as hypocretins, were initially identified to play a fundamental role in food intake, arousal and the regulation of sleep and wakefulness. Recent studies identified orexins to be critical for diverse physiological processes including motivation, reward, attention, emotional regulation, stress and anxiety. Here, I review recent findings that indicate orexin has an important role in acute and chronic stress. I also summarize the recent optogenetic and chemogenetic studies that have advanced our understanding of the orexin system. I will conclude by discussing clinical studies that implicate orexins in mental health disorders. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Derya Sargin
- Hotchkiss Brain Institute and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
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20
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Kowalska M, Kapelusiak-Pielok M, Grzelak T, Wypasek E, Kozubski W, Dorszewska J. The New *G29A and G1222A of HCRTR1, 5-HTTLPR of SLC6A4 Polymorphisms and Hypocretin-1, Serotonin Concentrations in Migraine Patients. Front Mol Neurosci 2018; 11:191. [PMID: 29922128 PMCID: PMC5996111 DOI: 10.3389/fnmol.2018.00191] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/15/2018] [Indexed: 01/03/2023] Open
Abstract
Migraine is one of the most common primary headache disorders that affects 11% of the adult population. The disease is divided into two main clinical subtypes: migraine with aura (MA) and migraine without aura (MO). Both serotonergic and hypocretinergic systems are involved in the migraine pathomechanism. Polymorphisms in the serotonin transporter gene (SLC6A4) and the hypocretin receptor 1 gene (HCRTR1) may be risk factors for migraine development due to their ability to affect serotonin and hypocretin-1 (HCRT-1) concentrations. The aim of the study was to analyze, for the first time in the Polish population, the 5-HT transporter linked polymorphic region (5-HTTLPR) in SLC6A4, G1222A (rs2271933) and the never before studied *G29A (rs41263963) polymorphisms in the HCRTR1 gene, as well as the 5-HT and hypocretin-1 plasma concentrations in migraine patients (MA, MO) and control subjects. The study included 123 patients that were diagnosed with migraine and 123 control subjects. Methods such as PCR, HRMA and sequencing were used for genotyping, while 5-HT was determined by HPLC/EC and hypocretin-1 by ELISA. No significant differences were observed in 5-HTTLPR frequencies. The A allele of HCRTR1 G1222A occurred more often in MO, while the GA genotype of HCRTR1 *G29A was more frequent among MA when compared to control group (p < 0.05). The mean age of migraine onset in individuals with HCRTR1 *G29A was 18 years old for patients with MA and 26 years old for MO patients. The localization and type of HCRTR1 polymorphisms (G1222A-missense variant in exon 7, *G29A-3'UTR variant) may predispose patients to the clinical subtype of migraine: MO or MA, respectively. In control subjects, the short allele of 5-HTTLPR tended to decrease the 5-HT concentration, while the A allele of HCRTR1 G1222A decreased both 5-HT and hypocretin-1 levels. Serotonin concentrations differed in terms of clinical features of migraine. The relation between genotypes of 5-HTTLPR, HCRTR1 G1222A, and 5-HT concentrations may bedisturbed in migraine. It seems that HCRTR1 *G29A is more strongly associated with regulating the 5-HT in patients with MA than MO, and therefore may contribute to the early age of onset for migraine.
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Affiliation(s)
- Marta Kowalska
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| | | | - Teresa Grzelak
- Department of Biology of Civilization-Linked Diseases, Poznan University of Medical Sciences, Poznan, Poland
| | - Ewa Wypasek
- Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University, Krakow, Poland.,The John Paul II Hospital, Krakow, Poland.,Institute of Cardiology, Jagiellonian University Medical College, Krakow, Poland
| | - Wojciech Kozubski
- Chair and Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| | - Jolanta Dorszewska
- Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
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21
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Liguori G, Tafuri S, Miyoshi C, Yanagisawa M, Squillacioti C, De Pasquale V, Mirabella N, Vittoria A, Costagliola A. Localization of orexin B and orexin-2 receptor in the rat epididymis. Acta Histochem 2018; 120:292-297. [PMID: 29496265 DOI: 10.1016/j.acthis.2018.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 12/30/2022]
Abstract
The peptides orexin A (OXA) and orexin B (OXB) derived from the proteolytic cleavage of a common precursor molecule, prepro-orexin, were originally described in the rat hypothalamus. Successively, they have been found in many other brain regions as well as in peripheral organs of mammals and other less evolved animals. The widespread localization of orexins accounts for the multiple activities that they exert in the body, including the regulation of energy homeostasis, feeding, metabolism, sleep and arousal, stress, addiction, and cardiovascular and endocrine functions. Both OXA and OXB peptides bind to two G-coupled receptors, orexin-1 (OX1R) and orexin-2 (OX2R) receptor, though with different binding affinity. Altered expression/activity of orexins and their receptors has been associated with a large number of human diseases. Though at present evidence highlighted a role for orexins and cognate receptors in mammalian reproduction, their central and/or local effects on gonadal functions remain poorly known. Here, we investigated the localization of OXB and OX2R in the rat epididymis. Immunohistochemical staining of sections from caput, corpus and cauda segments of the organ showed intense signals for both OXB and OX2R in the principal cells of the lining epithelium, while no staining was detected in the other cell types. Negative results were obtained from immunohistochemical analysis of hypothalamic and testicular tissues from OX2R knock-out mice (OX2R-/-) and OX1R/OX2R double knock-out (OX1R-/-; OX2R-/-) mice, thus demonstrating the specificity of the rabbit polyclonal anti-OX2R antibody used in our study. On contrary, the same antibody clearly showed the presence of OX2R in sections from hypothalamus and testis of normal mice and rats which are well known to express the receptor. Thus, our results provide the first definite evidence for the immunohistochemical localization of OXB and OX2R in the principal cells of rat epididymis.
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22
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Dimatelis JJ, Mtintsilana A, Naidoo V, Stein DJ, Russell VA. Chronic light exposure alters serotonergic and orexinergic systems in the rat brain and reverses maternal separation-induced increase in orexin receptors in the prefrontal cortex. Metab Brain Dis 2018; 33:433-441. [PMID: 29039077 DOI: 10.1007/s11011-017-0123-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 10/04/2017] [Indexed: 12/22/2022]
Abstract
Maternal separation (MS) is a well-established rodent model of depression. Chronic constant light (CCL) treatment during adolescence has been shown to reverse the depression-like behaviour induced by MS. We aimed to further delineate the antidepressant effect of light by investigating the involvement of the dopaminergic, serotonergic and orexinergic systems. MS was used to induce changes in adult male Sprague-Dawley rats, some of whom were also treated with CCL for 3 weeks during adolescence. At P80, rats were decapitated and brain tissue collected for analysis of glutamate- and potassium-stimulated dopamine release in the nucleus accumbens (NAc) using an in vitro superfusion technique. Enzyme-linked immunosorbent assays were employed to measure 5-hydroxytryptamine (5-HT) levels in the hypothalamus and prefrontal cortex (PFC). Western blotting was used to measure orexin receptor 1 (OXR-1) and 2 (OXR-2) in the PFC. MS did not affect 5-HT levels in these rats. However, CCL increased hypothalamic 5-HT and reduced 5-HT levels in the PFC. CCL had opposite effects on OXR levels in the PFC of maternally separated and non-separated rats. MS increased OXR-1 and OXR-2 levels in the PFC, an effect that was normalized by CCL treatment. MS reduced glutamate-stimulated dopamine release in the NAc, an effect that was not reversed by CCL. The present results suggest that CCL treatment affects 5-HT and orexinergic systems in the MS model while not affecting the MS-induced decrease in dopamine release in the NAc. The reversal of changes in the orexinergic system may be of particular relevance to the antidepressant effect of CCL in depression.
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Affiliation(s)
- J J Dimatelis
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa.
| | - A Mtintsilana
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - V Naidoo
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - D J Stein
- Department of Psychiatry and Mental Health and MRC Unit on Anxiety & Stress Disorders, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - V A Russell
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
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23
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Thompson MD, Sakurai T, Rainero I, Maj MC, Kukkonen JP. Orexin Receptor Multimerization versus Functional Interactions: Neuropharmacological Implications for Opioid and Cannabinoid Signalling and Pharmacogenetics. Pharmaceuticals (Basel) 2017; 10:ph10040079. [PMID: 28991183 PMCID: PMC5748636 DOI: 10.3390/ph10040079] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/29/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022] Open
Abstract
Orexins/hypocretins are neuropeptides formed by proteolytic cleavage of a precursor peptide, which are produced by neurons found in the lateral hypothalamus. The G protein-coupled receptors (GPCRs) for these ligands, the OX₁ and OX₂ orexin receptors, are more widely expressed throughout the central nervous system. The orexin/hypocretin system has been implicated in many pathways, and its dysregulation is under investigation in a number of diseases. Disorders in which orexinergic mechanisms are being investigated include narcolepsy, idiopathic sleep disorders, cluster headache and migraine. Human narcolepsy has been associated with orexin deficiency; however, it has only rarely been attributed to mutations in the gene encoding the precursor peptide. While gene variations within the canine OX₂ gene hcrtr2 have been directly linked with narcolepsy, the majority of human orexin receptor variants are weakly associated with diseases (the idiopathic sleep disorders, cluster headache and polydipsia-hyponatremia in schizophrenia) or are of potential pharmacogenetic significance. Evidence for functional interactions and/or heterodimerization between wild-type and variant orexin receptors and opioid and cannabinoid receptors is discussed in the context of its relevance to depression and epilepsy.
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Affiliation(s)
- Miles D Thompson
- Department of Pediatrics, University of California, San Diego 92093, CA, USA.
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa 920-8620, Japan.
| | - Innocenzo Rainero
- Department of Neuroscience, University of Turin, Torino 10124, Italy.
| | - Mary C Maj
- Department of Biochemistry, School of Medicine, Saint George's University, Saint George's 11739, Grenada.
| | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki 11739, Finland.
- Department of Physiology, Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki 00100, Finland.
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24
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Lu J, Zhao J, Balesar R, Fronczek R, Zhu QB, Wu XY, Hu SH, Bao AM, Swaab DF. Sexually Dimorphic Changes of Hypocretin (Orexin) in Depression. EBioMedicine 2017; 18:311-319. [PMID: 28377228 PMCID: PMC5405188 DOI: 10.1016/j.ebiom.2017.03.043] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 11/27/2022] Open
Abstract
Background Neurophysiological and behavioral processes regulated by hypocretin (orexin) are severely affected in depression. However, alterations in hypocretin have so far not been studied in the human brain. We explored the hypocretin system changes in the hypothalamus and cortex in depression from male and female subjects. Methods We quantified the differences between depression patients and well-matched controls, in terms of hypothalamic hypocretin-1 immunoreactivity (ir) and hypocretin receptors (Hcrtr-receptors)-mRNA in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex. In addition, we determined the alterations in the hypocretin system in a frequently used model for depression, the chronic unpredictable mild stress (CUMS) rat. Results i) Compared to control subjects, the amount of hypocretin-immunoreactivity (ir) was significantly increased in female but not in male depression patients; ii) hypothalamic hypocretin-ir showed a clear diurnal fluctuation, which was absent in depression; iii) male depressive patients who had committed suicide showed significantly increased ACC Hcrt-receptor-2-mRNA expression compared to male controls; and iv) female but not male CUMS rats showed a highly significant positive correlation between the mRNA levels of corticotropin-releasing hormone and prepro-hypocretin in the hypothalamus, and a significantly increased Hcrt-receptor-1-mRNA expression in the frontal cortex compared to female control rats. Conclusions The clear sex-related change found in the hypothalamic hypocretin-1-ir in depression should be taken into account in the development of hypocretin-targeted therapeutic strategies. Hypocretin (orexin) changes were studied in human postmortem brain in depression. A clear sex-related change was found in the hypothalamic hypocretin-1-immunoreactivity in depression. A rat depression model did not reflect the changes in the hypocretin system in the human brain in depression.
The stress systems of depressed patients are put into a higher gear by genetic and developmental factors. Over-reaction of these systems to stressful environmental situations makes people vulnerable to depression and suicide. This is the first postmortem study on changes in a relatively novel stress system in depression, consisting of the hypothalamic hypocretin neurons and hypocretin receptors in the prefrontal cortex. A clear sex-related change was found in the hypothalamic hypocretin-1-immunoreactivity in depression. Evaluation of the hypocretin system in a frequently used depression animal model, i.e. chronic unpredictable mild stress rats, did not replicate changes found in the hypocretin systems in the human brain in depression.
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Affiliation(s)
- Jing Lu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Mental Disorder's Management, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China; Zhejiang Province Key Laboratory of Mental Disorder's Management, Department of Psychiatry, First Affiliated Hospital, Zhejiang University School of Medicine
| | - Juan Zhao
- Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Rawien Balesar
- Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Rolf Fronczek
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Qiong-Bin Zhu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Mental Disorder's Management, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China
| | - Xue-Yan Wu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Mental Disorder's Management, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China
| | - Shao-Hua Hu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Mental Disorder's Management, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China; Zhejiang Province Key Laboratory of Mental Disorder's Management, Department of Psychiatry, First Affiliated Hospital, Zhejiang University School of Medicine
| | - Ai-Min Bao
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Mental Disorder's Management, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China.
| | - Dick F Swaab
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Mental Disorder's Management, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China; Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
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Luo X, Stavrakakis N, Penninx BW, Bosker FJ, Nolen WA, Boomsma DI, de Geus EJ, Smit JH, Snieder H, Nolte IM, Hartman CA. Does refining the phenotype improve replication rates? A review and replication of candidate gene studies on Major Depressive Disorder and Chronic Major Depressive Disorder. Am J Med Genet B Neuropsychiatr Genet 2016; 171B:215-36. [PMID: 26566975 DOI: 10.1002/ajmg.b.32396] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 10/14/2015] [Indexed: 11/10/2022]
Abstract
Replication has been poor for previously reported candidate genes involved in Major Depressive Disorder (MDD). One possible reason is phenotypic and genetic heterogeneity. The present study replicated genetic associations with MDD as defined in DSM-IV and with a more narrowly defined MDD subtype with a chronic and severe course. We first conducted a systematic review of genetic association studies on MDD published between September 2007 and June 2012 to identify all reported candidate genes. Genetic associations were then tested for all identified single nucleotide polymorphisms (SNPs) and the entire genes using data from the GAIN genome-wide association study (MDD: n = 1,352; chronic MDD subsample: n = 225; controls: n = 1,649). The 1,000 Genomes database was used as reference for imputation. From 157 studies identified inthe literature, 81 studies reported significant associations with MDD, involving 245 polymorphisms in 97 candidate genes, from which we were able to investigate 185 SNPs in 89 genes. We replicated nine candidate SNPs in eight genes for MDD and six in five genes for chronic MDD. However, these were not more than expected by chance. At gene level, we replicated 18 genes for MDD and 17 genes for chronic MDD, both significantly more than expected by chance. We showed that replication rates were improved for MDD compared to a previous, highly similar, replication study based on studies published before 2007. Effect sizes of the SNPs and replication rates of the candidate genes were improved in the chronic subsample compared to the full sample. Nonetheless, replication rates were still poor.
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Affiliation(s)
- Xiaochen Luo
- Interdisciplinary Centre Psychopathology and Emotion Regulation (ICPE), Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nikolaos Stavrakakis
- Interdisciplinary Centre Psychopathology and Emotion Regulation (ICPE), Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Brenda W Penninx
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Psychiatry, Leiden University Medical Center, Leiden, The Netherlands.,Department of Psychiatry, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Fokko J Bosker
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Willem A Nolen
- Interdisciplinary Centre Psychopathology and Emotion Regulation (ICPE), Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Dorret I Boomsma
- Department of Biological Psychology, VU University Amsterdam, Amsterdam, The Netherlands
| | - Eco J de Geus
- Department of Biological Psychology, VU University Amsterdam, Amsterdam, The Netherlands
| | - Johan H Smit
- Department of Psychiatry, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Harold Snieder
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ilja M Nolte
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Catharina A Hartman
- Interdisciplinary Centre Psychopathology and Emotion Regulation (ICPE), Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Chien YL, Liu CM, Shan JC, Lee HJ, Hsieh MH, Hwu HG, Chiou LC. Elevated plasma orexin A levels in a subgroup of patients with schizophrenia associated with fewer negative and disorganized symptoms. Psychoneuroendocrinology 2015; 53:1-9. [PMID: 25560205 DOI: 10.1016/j.psyneuen.2014.12.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/29/2014] [Accepted: 12/15/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND Orexin A and B, a pair of hypothalamic neuropeptides also named hypocretin 1 and 2, play a role in the regulation of arousal, appetite, reward, attention, and cognition. Animal studies showed that antipsychotics can activate orexin neurons in a manner correlated with their weight gain liability. However, little is known about the role of orexin in patients with schizophrenia. This study aimed to investigate the correlation of plasma orexin level with clinical symptom profile, neurocognitive functioning and weight gain liability of the antipsychotics taken in patients with schizophrenia. METHODS We measured plasma levels of orexin A in 127 patients with schizophrenia and 34 healthy controls by radioimmunoassay. In patients, we assessed clinical symptoms on the Positive and Negative Syndrome Scale and executive function by the Wisconsin Card Sorting test (WCST), and examined their associations with plasma orexin A level. RESULTS Patients with schizophrenia had a significantly higher mean orexin A level than healthy controls (60.7±37.9 vs. 38.8±15.5pg/ml). Patients were divided into two subgroups based on their orexin A levels that were distributed in two clusters divided by 80pg/ml. Patients in the high-orexin subgroup had significantly fewer negative and disorganized symptoms, and tended to have fewer perseverative errors, more failure to maintain set yet comparable category achieved on the WCST than the normal-orexin subgroup. There was no significant difference in orexin A levels among patients taking antipsychotics with different weight gain liabilities. CONCLUSION Higher level of orexin A seems to be related to favorable clinical symptom profiles of schizophrenia, but the causal relationship needs further clarification.
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Affiliation(s)
- Yi-Ling Chien
- Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Min Liu
- Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jia-Chi Shan
- Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan; Department of Psychiatry, Cathay General Hospital, Taipei, Taiwan
| | - Hsin-Jung Lee
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming H Hsieh
- Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan; Neurobiology and Cognitive Science Center, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hai-Gwo Hwu
- Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Lih-Chu Chiou
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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Jalewa J, Wong-Lin K, McGinnity TM, Prasad G, Hölscher C. Increased number of orexin/hypocretin neurons with high and prolonged external stress-induced depression. Behav Brain Res 2014; 272:196-204. [DOI: 10.1016/j.bbr.2014.05.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 05/13/2014] [Accepted: 05/16/2014] [Indexed: 01/14/2023]
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Deats SP, Adidharma W, Lonstein JS, Yan L. Attenuated orexinergic signaling underlies depression-like responses induced by daytime light deficiency. Neuroscience 2014; 272:252-60. [PMID: 24813431 DOI: 10.1016/j.neuroscience.2014.04.069] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 04/24/2014] [Accepted: 04/28/2014] [Indexed: 01/01/2023]
Abstract
Light has profound effects on mood, as exemplified by seasonal affective disorder (SAD) and the beneficial effects of bright light therapy. However, the underlying neural pathways through which light regulates mood are not well understood. Our previous work has developed the diurnal grass rat, Arvicanthis niloticus, as an animal model of SAD (Leach et al., 2013a,b). By utilizing a 12:12-h dim light:dark (DLD) paradigm that simulates the lower light intensity of winter, we showed that the animals housed in DLD exhibited increased depression-like behaviors in the forced swim test (FST) and sweet solution preference (SSP) compared to animals housed in bright light during the day (BLD). The objective of the present study was to test the hypothesis that light affects mood by acting on the brain orexinergic system in the diurnal grass rat model of SAD. First, orexin A immunoreactivity (OXA-ir) was examined in DLD and BLD grass rats. Results revealed a reduction in the number of OXA-ir neurons in the hypothalamus and attenuated OXA-ir fiber density in the dorsal raphe nucleus of animals in the DLD compared to those in the BLD group. Then, the animals in BLD were treated systemically with SB-334867, a selective orexin 1 receptor (OX1R) antagonist, which led to a depressive phenotype characterized by increased immobility in the FST and a decrease in SSP compared to vehicle-treated controls. Results suggest that attenuated orexinergic signaling is associated with increased depression-like behaviors in grass rats, and support the hypothesis that the orexinergic system mediates the effects of light on mood.
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Affiliation(s)
- S P Deats
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - W Adidharma
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - J S Lonstein
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - L Yan
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
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Thompson MD, Xhaard H, Sakurai T, Rainero I, Kukkonen JP. OX1 and OX2 orexin/hypocretin receptor pharmacogenetics. Front Neurosci 2014; 8:57. [PMID: 24834023 PMCID: PMC4018553 DOI: 10.3389/fnins.2014.00057] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 03/12/2014] [Indexed: 01/01/2023] Open
Abstract
Orexin/hypocretin peptide mutations are rare in humans. Even though human narcolepsy is associated with orexin deficiency, this is only extremely rarely due to mutations in the gene coding prepro-orexin, the precursor for both orexin peptides. In contrast, coding and non-coding variants of the OX1 and OX2 orexin receptors have been identified in many human populations; sometimes, these have been associated with disease phenotype, although most confer a relatively low risk. In most cases, these studies have been based on a candidate gene hypothesis that predicts the involvement of orexins in the relevant pathophysiological processes. In the current review, the known human OX1/HCRTR1 and OX2/HCRTR2 genetic variants/polymorphisms as well as studies concerning their involvement in disorders such as narcolepsy, excessive daytime sleepiness, cluster headache, polydipsia-hyponatremia in schizophrenia, and affective disorders are discussed. In most cases, the functional cellular or pharmacological correlates of orexin variants have not been investigated—with the exception of the possible impact of an amino acid 10 Pro/Ser variant of OX2 on orexin potency—leaving conclusions on the nature of the receptor variant effects speculative. Nevertheless, we present perspectives that could shape the basis for further studies. The pharmacology and other properties of the orexin receptor variants are discussed in the context of GPCR signaling. Since orexinergic therapeutics are emerging, the impact of receptor variants on the affinity or potency of ligands deserves consideration. This perspective (pharmacogenetics) is also discussed in the review.
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Affiliation(s)
- Miles D Thompson
- University of Toronto Epilepsy Research Program, Department of Pharmacology, University of Toronto Toronto, ON, Canada
| | - Henri Xhaard
- Faculty of Pharmacy, Centre for Drug Research, University of Helsinki Helsinki, Finland
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
| | | | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki Helsinki, Finland
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Yeoh JW, Campbell EJ, James MH, Graham BA, Dayas CV. Orexin antagonists for neuropsychiatric disease: progress and potential pitfalls. Front Neurosci 2014; 8:36. [PMID: 24616658 PMCID: PMC3934415 DOI: 10.3389/fnins.2014.00036] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 02/10/2014] [Indexed: 11/20/2022] Open
Abstract
The tight regulation of sleep/wake states is critical for mental and physiological wellbeing. For example, dysregulation of sleep/wake systems predisposes individuals to metabolic disorders such as obesity and psychiatric problems, including depression. Contributing to this understanding, the last decade has seen significant advances in our appreciation of the complex interactions between brain systems that control the transition between sleep and wake states. Pivotal to our increased understanding of this pathway was the description of a group of neurons in the lateral hypothalamus (LH) that express the neuropeptides orexin A and B (hypocretin, Hcrt-1 and Hcrt-2). Orexin neurons were quickly placed at center stage with the demonstration that loss of normal orexin function is associated with the development of narcolepsy—a condition in which sufferers fail to maintain normal levels of daytime wakefulness. Since these initial seminal findings, much progress has been made in our understanding of the physiology and function of the orexin system. For example, the orexin system has been identified as a key modulator of autonomic and neuroendocrine function, arousal, reward and attention. Notably, studies in animals suggest that dysregulation of orexin function is associated with neuropsychiatric states such as addiction and mood disorders including depression and anxiety. This review discusses the progress associated with therapeutic attempts to restore orexin system function and treat neuropsychiatric conditions such as addiction, depression and anxiety. We also highlight potential pitfalls and challenges associated with targeting this system to treat these neuropsychiatric states.
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Affiliation(s)
- Jiann Wei Yeoh
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Erin J Campbell
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Morgan H James
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Brett A Graham
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Christopher V Dayas
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
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Abstract
The hypocretin system is constituted by a small group of hypothalamic neurons with widespread connections within the entire central nervous system producing two neuropeptides involved in several key physiological functions such as the regulation of sleep and wakefulness, motor control, autonomic functions, metabolism, feeding behavior, and reward. Narcolepsy with cataplexy is a neurological disorder regarded as a disease model for the selective hypocretin system damage, and also shares several psychopatological traits and comorbidities with psychiatric disorders. We reviewed the available literature on the involvement of the hypocretin system in psychiatric nosography. Different evidences such as cerebrospinal hypocretin-1 levels, genetic polymorphisms of the neuropeptides or their receptors, response to treatments, clinical, experimental and functional data directly or indirectly linked the hypocretin system to schizophrenia, mood, anxiety and eating disorders, as well as to addiction. Future genetic and pharmacological studies will disentangle the hypocretin system role in the field of psychiatry.
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Affiliation(s)
- Fabio Pizza
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Ugo Foscolo 7, 40123, Bologna, Italy
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Ye R, Carneiro AMD, Airey D, Sanders-Bush E, Williams RW, Lu L, Wang J, Zhang B, Blakely RD. Evaluation of heritable determinants of blood and brain serotonin homeostasis using recombinant inbred mice. GENES BRAIN AND BEHAVIOR 2013; 13:247-60. [PMID: 24102824 DOI: 10.1111/gbb.12092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/01/2013] [Accepted: 10/01/2013] [Indexed: 12/31/2022]
Abstract
The biogenic amine serotonin (5-HT, 5-hydroxytryptamine) exerts powerful, modulatory control over multiple physiological functions in the brain and periphery, ranging from mood and appetite to vasoconstriction and gastrointestinal motility. In order to gain insight into shared and distinct molecular and phenotypic networks linked to variations in 5-HT homeostasis, we capitalized on the stable genetic variation present in recombinant inbred mouse strains. This family of strains, all derived from crosses between C57BL/6J and DBA/2J (BXD) parents, represents a unique, community resource with approximately 40 years of assembled phenotype data that can be exploited to explore and test causal relationships in silico. We determined levels of 5-HT and 5-hydroxyindoleacetic acid from whole blood, midbrain and thalamus/hypothalamus (diencephalon) of 38 BXD lines and both sexes. All 5-HT measures proved highly heritable in each region, although both gender and region significantly impacted between-strain correlations. Our studies identified both expected and novel biochemical, anatomical and behavioral phenotypes linked to 5-HT traits, as well as distinct quantitative trait loci. Analyses of these loci nominate a group of genes likely to contribute to gender- and region-specific capacities for 5-HT signaling. Analysis of midbrain mRNA variations across strains revealed overlapping gene expression networks linked to 5-HT synthesis and metabolism. Altogether, our studies provide a rich profile of genomic, molecular and phenotypic networks that can be queried for novel relationships contributing risk for disorders linked to perturbed 5-HT signaling.
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Affiliation(s)
- R Ye
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville
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Abstract
Depression is a devastating mental disorder with an increasing impact throughout the world, whereas the efficacy of currently available pharmacological treatment is still limited. Growing evidence from preclinical and clinical studies suggests that orexins (neuropeptides that are also known as hypocretins) and their receptors are involved in the physiopathology of depression. Indeed, the orexinergic system regulates functions that are disturbed in depressive states such as sleep, reward system, feeding behavior, the stress response and monoaminergic neurotransmission. Nevertheless, the precise role of orexins in behavioral and neurophysiological impairments observed in depression is still unclear. Both hypoactivity and hyperactivity of orexin signaling pathways have been found to be associated with depression. These discrepancies in the literature prompted the necessity for additional investigations, as the orexinergic system appears to be a promising target to treat the symptoms of depression. This assumption is underlined by recent data suggesting that pharmacological blockade of orexin receptors induces a robust antidepressant-like effect in an animal model of depression. Further preclinical and clinical studies are needed to progress the overall understanding of the orexinergic alterations in depression, which will eventually translate preliminary observations into real therapeutic potential. The aim of this paper is to provide an overview of human and animal research dedicated to the study of the specific involvement of orexins in depression, and to propose a framework in which disturbances of the orexinergic system are regarded as an integral component of the etiology of depression.
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Affiliation(s)
- Mathieu Nollet
- UMR Inserm 930-Imagerie et Cerveau, Equipe 4: Troubles Affectifs, Université François-Rabelais de Tours, UFR Sciences et Techniques, Parc Grandmont, 37200 Tours, France
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Kukkonen JP. Physiology of the orexinergic/hypocretinergic system: a revisit in 2012. Am J Physiol Cell Physiol 2012; 304:C2-32. [PMID: 23034387 DOI: 10.1152/ajpcell.00227.2012] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The neuropeptides orexins and their G protein-coupled receptors, OX(1) and OX(2), were discovered in 1998, and since then, their role has been investigated in many functions mediated by the central nervous system, including sleep and wakefulness, appetite/metabolism, stress response, reward/addiction, and analgesia. Orexins also have peripheral actions of less clear physiological significance still. Cellular responses to the orexin receptor activity are highly diverse. The receptors couple to at least three families of heterotrimeric G proteins and other proteins that ultimately regulate entities such as phospholipases and kinases, which impact on neuronal excitation, synaptic plasticity, and cell death. This article is a 10-year update of my previous review on the physiology of the orexinergic/hypocretinergic system. I seek to provide a comprehensive update of orexin physiology that spans from the molecular players in orexin receptor signaling to the systemic responses yet emphasizing the cellular physiological aspects of this system.
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Affiliation(s)
- Jyrki P Kukkonen
- Dept. of Veterinary Biosciences, University of Helsinki, Finland.
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Steiner MA, Lecourt H, Jenck F. The brain orexin system and almorexant in fear-conditioned startle reactions in the rat. Psychopharmacology (Berl) 2012; 223:465-75. [PMID: 22592903 DOI: 10.1007/s00213-012-2736-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 04/24/2012] [Indexed: 12/24/2022]
Abstract
RATIONALE The rat fear-potentiated startle (FPS) paradigm is a translational model of conditioned fear involving central amygdala pathways of the brain. Hypothalamic orexin neurons have input-output projections to the amygdala; they modulate vigilance and stress-related responses. OBJECTIVE To investigate whether the transient pharmacological blockade of orexin receptors moderates the conditioned fear response. METHODS F344 rats received acute oral treatment with the dual orexin receptor antagonist almorexant (30-300 mg/kg) or with one of the clinically effective anxiolytics diazepam (1-10 mg/kg), buspirone (10-100 mg/kg), fluoxetine (3-30 mg/kg), and sertraline (10-100 mg/kg). Drug effects on startle responses were assessed in both fear- and non-fear-conditioned rats; on forepaw grip and horizontal wire motor performance, and on elevated plus maze (EPM) behavior. RESULTS Diazepam and almorexant both dose-dependently decreased FPS in the presence of the fear-conditioned stimulus (CS; light) more prominently than background startle in absence of the CS (dark). Diazepam induced myorelaxation and reduced startle responses in control non-fear-conditioned rats. Almorexant had no myorelaxant effects and left startle responses under light in non-fear-conditioned rats intact. On the EPM, diazepam showed anxiolytic-like effects, almorexant not. Buspirone demonstrated anxiolytic-like effects on FPS by simultaneously reducing CS-related startle and increasing no-CS-background startle. Fluoxetine did not affect FPS, whereas sertraline showed anxiogenic-like effects. CONCLUSIONS Almorexant reduced FPS, but did not affect EPM behavior. Almorexant's overall pattern of effects on FPS was comparable to but less pronounced than that of the anxiolytic benzodiazepine diazepam. The endogenous orexin system actively contributes to fear-conditioned startle reactions in the rat.
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Affiliation(s)
- Michel A Steiner
- Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, 4123 Allschwil, Switzerland.
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Gene-based analysis of regionally enriched cortical genes in GWAS data sets of cognitive traits and psychiatric disorders. PLoS One 2012; 7:e31687. [PMID: 22384057 PMCID: PMC3285182 DOI: 10.1371/journal.pone.0031687] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 01/10/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite its estimated high heritability, the genetic architecture leading to differences in cognitive performance remains poorly understood. Different cortical regions play important roles in normal cognitive functioning and impairment. Recently, we reported on sets of regionally enriched genes in three different cortical areas (frontomedial, temporal and occipital cortices) of the adult rat brain. It has been suggested that genes preferentially, or specifically, expressed in one region or organ reflect functional specialisation. Employing a gene-based approach to the analysis, we used the regionally enriched cortical genes to mine a genome-wide association study (GWAS) of the Norwegian Cognitive NeuroGenetics (NCNG) sample of healthy adults for association to nine psychometric tests measures. In addition, we explored GWAS data sets for the serious psychiatric disorders schizophrenia (SCZ) (n = 3 samples) and bipolar affective disorder (BP) (n = 3 samples), to which cognitive impairment is linked. PRINCIPAL FINDINGS At the single gene level, the temporal cortex enriched gene RAR-related orphan receptor B (RORB) showed the strongest overall association, namely to a test of verbal intelligence (Vocabulary, P = 7.7E-04). We also applied gene set enrichment analysis (GSEA) to test the candidate genes, as gene sets, for enrichment of association signal in the NCNG GWAS and in GWASs of BP and of SCZ. We found that genes differentially expressed in the temporal cortex showed a significant enrichment of association signal in a test measure of non-verbal intelligence (Reasoning) in the NCNG sample. CONCLUSION Our gene-based approach suggests that RORB could be involved in verbal intelligence differences, while the genes enriched in the temporal cortex might be important to intellectual functions as measured by a test of reasoning in the healthy population. These findings warrant further replication in independent samples on cognitive traits.
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