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Mavanji V, Pomonis BL, Shekels L, Kotz CM. Interactions between Lateral Hypothalamic Orexin and Dorsal Raphe Circuitry in Energy Balance. Brain Sci 2024; 14:464. [PMID: 38790443 PMCID: PMC11117928 DOI: 10.3390/brainsci14050464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/30/2024] [Accepted: 05/04/2024] [Indexed: 05/26/2024] Open
Abstract
Orexin/hypocretin terminals innervate the dorsal raphe nucleus (DRN), which projects to motor control areas important for spontaneous physical activity (SPA) and energy expenditure (EE). Orexin receptors are expressed in the DRN, and obesity-resistant (OR) rats show higher expression of these receptors in the DRN and elevated SPA/EE. We hypothesized that orexin-A in the DRN enhances SPA/EE and that DRN-GABA modulates the effect of orexin-A on SPA/EE. We manipulated orexin tone in the DRN either through direct injection of orexin-A or through the chemogenetic activation of lateral-hypothalamic (LH) orexin neurons. In the orexin neuron activation experiment, fifteen minutes prior to the chemogenetic activation of orexin neurons, the mice received either the GABA-agonist muscimol or antagonist bicuculline injected into the DRN, and SPA/EE was monitored for 24 h. In a separate experiment, orexin-A was injected into the DRN to study the direct effect of DRN orexin on SPA/EE. We found that the activation of orexin neurons elevates SPA/EE, and manipulation of GABA in the DRN does not alter the SPA response to orexin neuron activation. Similarly, intra-DRN orexin-A enhanced SPA and EE in the mice. These results suggest that orexin-A in the DRN facilitates negative energy balance by increasing physical activity-induced EE, and that modulation of DRN orexin-A is a potential strategy to promote SPA and EE.
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Affiliation(s)
- Vijayakumar Mavanji
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Brianna L. Pomonis
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Laurie Shekels
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Catherine M. Kotz
- Research Service, Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; (V.M.); (B.L.P.); (L.S.)
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
- Geriatric Research, Education and Clinical Center, Minneapolis VA Health Care System, Minneapolis, MN 55417, USA
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2
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Ito H, Fukatsu N, Rahaman SM, Mukai Y, Izawa S, Ono D, Kilduff TS, Yamanaka A. Deficiency of orexin signaling during sleep is involved in abnormal REM sleep architecture in narcolepsy. Proc Natl Acad Sci U S A 2023; 120:e2301951120. [PMID: 37796986 PMCID: PMC10576136 DOI: 10.1073/pnas.2301951120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/10/2023] [Indexed: 10/07/2023] Open
Abstract
Narcolepsy is a sleep disorder caused by deficiency of orexin signaling. However, the neural mechanisms by which deficient orexin signaling causes the abnormal rapid eye movement (REM) sleep characteristics of narcolepsy, such as cataplexy and frequent transitions to REM states, are not fully understood. Here, we determined the activity dynamics of orexin neurons during sleep that suppress the abnormal REM sleep architecture of narcolepsy. Orexin neurons were highly active during wakefulness, showed intermittent synchronous activity during non-REM (NREM) sleep, were quiescent prior to the transition from NREM to REM sleep, and a small subpopulation of these cells was active during REM sleep. Orexin neurons that lacked orexin peptides were less active during REM sleep and were mostly silent during cataplexy. Optogenetic inhibition of orexin neurons established that the activity dynamics of these cells during NREM sleep regulate NREM-REM sleep transitions. Inhibition of orexin neurons during REM sleep increased subsequent REM sleep in "orexin intact" mice and subsequent cataplexy in mice lacking orexin peptides, indicating that the activity of a subpopulation of orexin neurons during the preceding REM sleep suppresses subsequent REM sleep and cataplexy. Thus, these results identify how deficient orexin signaling during sleep results in the abnormal REM sleep architecture characteristic of narcolepsy.
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Affiliation(s)
- Hiroto Ito
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
- Japan Society for the Promotion of Science Research Fellowship for Young Scientists, Tokyo102-0083, Japan
| | - Noriaki Fukatsu
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Sheikh Mizanur Rahaman
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Yasutaka Mukai
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Shuntaro Izawa
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Thomas S. Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA94025
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
- Chinese Institute for Brain Research, Beijing102206, China
- National Institute for Physiological Sciences, Aichi444-8585, Japan
- National Institutes of Natural Sciences, Aichi444-8585, Japan
- Division of Brain Sciences Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo160-8582, Japan
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3
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Somach RT, Jean ID, Farrugia AM, Cohen AS. Mild Traumatic Brain Injury Affects Orexin/Hypocretin Physiology Differently in Male and Female Mice. J Neurotrauma 2023; 40:2146-2163. [PMID: 37476962 PMCID: PMC10701510 DOI: 10.1089/neu.2023.0125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023] Open
Abstract
Traumatic brain injury (TBI) is known to affect the physiology of neural circuits in several brain regions, which can contribute to behavioral changes after injury. Disordered sleep is a behavior that is often seen after TBI, but there is little research into how injury affects the circuitry that contributes to disrupted sleep regulation. Orexin/hypocretin neurons (hereafter referred to as orexin neurons) located in the lateral hypothalamus normally stabilize wakefulness in healthy animals and have been suggested as a source of dysregulated sleep behavior. Despite this, few studies have examined how TBI affects orexin neuron circuitry. Further, almost no animal studies of orexin neurons after TBI have included female animals. Here, we address these gaps by studying changes to orexin physiology using ex vivo acute brain slices and whole-cell patch clamp recording. We hypothesized that orexin neurons would have reduced afferent excitatory activity after injury. Ultimately, this hypothesis was supported but there were additional physiological changes that occurred that we did not originally hypothesize. We studied physiological properties in orexin neurons approximately 1 week after mild traumatic brain injury (mTBI) in 6-8-week-old male and female mice. mTBI was performed with a lateral fluid percussion injury between 1.4 and 1.6 atmospheres. Mild TBI increased the size of action potential afterhyperpolarization in orexin neurons from female mice, but not male mice and reduced the action potential threshold in male mice, but not in female mice. Mild TBI reduced afferent excitatory activity and increased afferent inhibitory activity onto orexin neurons. Alterations in afferent excitatory activity occurred in different parameters in male and female animals. The increased afferent inhibitory activity after injury is more pronounced in recordings from female animals. Our results indicate that mTBI changes the physiology of orexin neuron circuitry and that these changes are not the same in male and female animals.
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Affiliation(s)
- Rebecca T. Somach
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ian D. Jean
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Anthony M. Farrugia
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Akiva S. Cohen
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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4
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Peleg-Raibstein D, Viskaitis P, Burdakov D. Eat, seek, rest? An orexin/hypocretin perspective. J Neuroendocrinol 2023; 35:e13259. [PMID: 36994677 DOI: 10.1111/jne.13259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/19/2023]
Abstract
Seeking and ingesting nutrients is an essential cycle of life in all species. In classical neuropsychology these two behaviours are viewed as fundamentally distinct from each other, and known as appetitive and consummatory, respectively. Appetitive behaviour is highly flexible and diverse, but typically involves increased locomotion and spatial exploration. Consummatory behaviour, in contrast, typically requires reduced locomotion. Another long-standing concept is "rest and digest", a hypolocomotive response to calorie intake, thought to facilitate digestion and storage of energy after eating. Here, we note that the classical seek➔ingest➔rest behavioural sequence is not evolutionarily advantageous for all ingested nutrients. Our limited stomach capacity should be invested wisely, rather than spent on the first available nutrient. This is because nutrients are not simply calories: some nutrients are more essential for survival than others. Thus, a key choice that needs to be made soon after ingestion: to eat more and rest, or to terminate eating and search for better food. We offer a perspective on recent work suggesting how nutrient-specific neural responses shape this choice. Specifically, the hypothalamic hypocretin/orexin neurons (HONs) - cells that promote hyperlocomotive explorative behaviours - are rapidly and differentially modulated by different ingested macronutrients. Dietary non-essential (but not essential) amino acids activate HONs, while glucose depresses HONs. This nutrient-specific HON modulation engages distinct reflex arcs, seek➔ingest➔seek and seek➔ingest➔rest, respectively. We propose that these nutri-neural reflexes evolved to facilitate optimal nutrition despite the limitations of our body.
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Affiliation(s)
- Daria Peleg-Raibstein
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
| | - Paulius Viskaitis
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
| | - Denis Burdakov
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
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5
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Conde K, Fang S, Xu Y. Unraveling the serotonin saga: from discovery to weight regulation and beyond - a comprehensive scientific review. Cell Biosci 2023; 13:143. [PMID: 37550777 PMCID: PMC10408233 DOI: 10.1186/s13578-023-01091-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/21/2023] [Indexed: 08/09/2023] Open
Abstract
The prevalence of obesity is rapidly increasing worldwide, while the development of effective obesity therapies lags behind. Although new therapeutic targets to alleviate obesity are identified every day, and drug efficacy is improving, adverse side effects and increased health risks remain serious issues facing the weight-loss industry. Serotonin, also known as 5-HT, has been extensively studied in relation to appetite reduction and weight loss. As a result, dozens of upstream and downstream neural targets of 5-HT have been identified, revealing a multitude of neural circuits involved in mediating the anorexigenic effect of 5-HT. Despite the rise and fall of several 5-HT therapeutics in recent decades, the future of 5-HT as a therapeutic target for weight-loss therapy looks promising. This review focuses on the history of serotonin, the state of current central serotonin research, previous serotonergic therapies, and the future of serotonin for treating individuals with obesity.
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Affiliation(s)
- Kristine Conde
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, USA.
| | - Shuzheng Fang
- College of Art and Sciences, Washington University in St. Louis, St. Louis, MO, USA
| | - Yong Xu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, USA.
- Section of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Houston, TX, 77030, USA.
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6
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Saitoh T, Sakurai T. The Present and Future of Synthetic Orexin Receptor Agonists. Peptides 2023:171051. [PMID: 37422012 DOI: 10.1016/j.peptides.2023.171051] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/16/2023] [Accepted: 07/02/2023] [Indexed: 07/10/2023]
Abstract
The neuropeptide orexin/hypocretin plays a crucial role in various physiological processes, including the regulation of sleep/wakefulness, appetite, emotion and the reward system. Dysregulation of orexin signaling has been implicated in hypersomnia, especially in narcolepsy, which is a chronic neurological disorder characterized by excessive daytime sleepiness (EDS), sudden loss of muscle tone while awake (cataplexy), sleep paralysis, and hallucinations. Small-molecule orexin receptor agonists have emerged as promising therapeutics for these disorders, and significant progress has been made in this field in the past decade. This review summarizes recent advances in the design and synthesis of orexin receptor agonists, with a focus on peptidic and small-molecule OX2R-selective, dual, and OX1R-selective agonists. The review discusses the key structural features and pharmacological properties of these agonists, as well as their potential therapeutic applications. DATA AVAILABILITY: No data was used for the research described in the article.
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Affiliation(s)
- Tsuyoshi Saitoh
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; International Institute for Integrative Sleep Medicine (IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Takeshi Sakurai
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; International Institute for Integrative Sleep Medicine (IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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7
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Kniazkina M, Dyachuk V. Does EGFR Signaling Mediate Orexin System Activity in Sleep Initiation? Int J Mol Sci 2023; 24:ijms24119505. [PMID: 37298454 DOI: 10.3390/ijms24119505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/21/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
Sleep-wake cycle disorders are an important symptom of many neurological diseases, including Parkinson's disease, Alzheimer's disease, and multiple sclerosis. Circadian rhythms and sleep-wake cycles play a key role in maintaining the health of organisms. To date, these processes are still poorly understood and, therefore, need more detailed elucidation. The sleep process has been extensively studied in vertebrates, such as mammals and, to a lesser extent, in invertebrates. A complex, multi-step interaction of homeostatic processes and neurotransmitters provides the sleep-wake cycle. Many other regulatory molecules are also involved in the cycle regulation, but their functions remain largely unclear. One of these signaling systems is epidermal growth factor receptor (EGFR), which regulates the activity of neurons in the modulation of the sleep-wake cycle in vertebrates. We have evaluated the possible role of the EGFR signaling pathway in the molecular regulation of sleep. Understanding the molecular mechanisms that underlie sleep-wake regulation will provide critical insight into the fundamental regulatory functions of the brain. New findings of sleep-regulatory pathways may provide new drug targets and approaches for the treatment of sleep-related diseases.
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Affiliation(s)
- Marina Kniazkina
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia
| | - Vyacheslav Dyachuk
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia
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8
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Maruyama T, Ueta Y. Internal and external modulation factors of the orexin system (REVIEW). Peptides 2023; 165:171009. [PMID: 37054895 DOI: 10.1016/j.peptides.2023.171009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 04/15/2023]
Abstract
Orexin-A and -B (identical to hypocretin-1 and -2) are neuropeptides synthesized in the lateral hypothalamus and perifornical area, and orexin neurons project their axon terminals broadly throughout the entire central nervous system (CNS). The activity of orexins is mediated by two specific G protein-coupled receptors (GPCRs), termed orexin type1 receptor (OX1R) and orexin type2 receptor (OX2R). The orexin system plays a relevant role in various physiological functions, including arousal, feeding, reward, and thermogenesis, and is key to human health. Orexin neurons receive various signals related to environmental, physiological, and emotional stimuli. Previous studies have reported that several neurotransmitters and neuromodulators influence the activation or inhibition of orexin neuron activity. In this review, we summarize the modulating factors of orexin neurons in the sleep/wake rhythm and feeding behavior, particularly in the context of the modulation of appetite, body fluids, and circadian signaling. We also describe the effects of life activity, behavior, and diet on the orexin system. Some studies have observed phenomena that have been verified in animal experiments, revealing the detailed mechanism and neural pathway, while their applications to humans is expected in future research.
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Affiliation(s)
- Takashi Maruyama
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Japan.
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Japan
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9
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Hung C, Yamanaka A. The role of orexin neuron activity in sleep/wakefulness regulation. Peptides 2023; 165:171007. [PMID: 37030519 DOI: 10.1016/j.peptides.2023.171007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/03/2023] [Accepted: 04/03/2023] [Indexed: 04/10/2023]
Abstract
Orexin (also known as hypocretin) is a neuropeptide exclusively synthesized in the neurons of the lateral hypothalamus (LH). Initially orexin was thought to be involved in the regulation of feeding behavior. However, it is now known to also be a critical regulator of sleep/wakefulness, especially the maintenance of wakefulness. Although the somas of orexin neurons are exclusively located in the LH, these neurons send axons throughout the brain and spinal cord. Orexin neurons integrate inputs from various brain regions and project to neurons that are involved in the regulation of sleep/wakefulness. Orexin knockout mice have a fragmentation of sleep/wakefulness and cataplexy-like behavior arrest, which is similar to the sleep disorder narcolepsy. Recent progress with manipulation of neural activity of targeted neurons, using experimental tools such as optogenetics and chemogenetics, has emphasized the role of orexin neuron activity on the regulation of sleep/wakefulness. Recording of orexin neuron activity in vivo using electrophysiological and gene-encoded calcium indicator proteins revealed that these cells have specific activity patterns across sleep/wakefulness state changes. Here, we also discuss not only the role of the orexin peptide, but also the role of other co-transmitters that are synthesized and released from orexin neurons and involved in sleep/wakefulness regulation.
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Affiliation(s)
- Chijung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Akihiro Yamanaka
- Chinese Institute for Brain Research, Beijing (CIBR), Beijing, 102206, China; National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi 444-8585 Japan; Division of Brain Sciences Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, 160-8582, Japan.
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10
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Beckenstrom AC, Coloma PM, Dawson GR, Finlayson AK, Malik A, Post A, Steiner MA, Potenza MN. Use of experimental medicine approaches for the development of novel psychiatric treatments based on orexin receptor modulation. Neurosci Biobehav Rev 2023; 147:105107. [PMID: 36828161 PMCID: PMC10165155 DOI: 10.1016/j.neubiorev.2023.105107] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/08/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023]
Abstract
Despite progress in understanding the pathological mechanisms underlying psychiatric disorders, translation from animal models into clinical use remains a significant bottleneck. Preclinical studies have implicated the orexin neuropeptide system as a potential target for psychiatric disorders through its role in regulating emotional, cognitive, and behavioral processes. Clinical studies are investigating orexin modulation in addiction and mood disorders. Here we review performance-outcome measures (POMs) arising from experimental medicine research methods which may show promise as markers of efficacy of orexin receptor modulators in humans. POMs provide objective measures of brain function, complementing patient-reported or clinician-observed symptom evaluation, and aid the translation from preclinical to clinical research. Significant challenges include the development, validation, and operationalization of these measures. We suggest that collaborative networks comprising clinical practitioners, academics, individuals working in the pharmaceutical industry, drug regulators, patients, patient advocacy groups, and other relevant stakeholders may provide infrastructure to facilitate validation of experimental medicine approaches in translational research and in the implementation of these approaches in real-world clinical practice.
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Affiliation(s)
- Amy C Beckenstrom
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK.
| | - Preciosa M Coloma
- Idorsia Pharmaceuticals Ltd, Hegenheimermattweg 91, Allschwil 4123, Switzerland
| | - Gerard R Dawson
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK
| | - Ailidh K Finlayson
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK; Department of Psychology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Asad Malik
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK
| | - Anke Post
- Corlieve Therapeutics, Swiss Innovation Park, Hegenheimermattweg 167A, 4123 Allschwil, Switzerland
| | | | - Marc N Potenza
- Departments of Psychiatry and Neuroscience and the Child Study Center, Yale School of Medicine, 1 Church Street, Room 726, New Haven, CT 06510, USA; Connecticut Mental Health Center, 34 Park Street, New Haven, CT 06519, USA; Connecticut Council on Problem Gambling, Wethersfield, CT, USA; The Wu Tsai Institute, Yale University, 100 College St, New Haven, CT 06510, USA
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11
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Sheibani M, Shayan M, Khalilzadeh M, Ghasemi M, Dehpour AR. Orexin receptor antagonists in the pathophysiology and treatment of sleep disorders and epilepsy. Neuropeptides 2023; 99:102335. [PMID: 37003137 DOI: 10.1016/j.npep.2023.102335] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/20/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023]
Abstract
The correlation between sleep and epilepsy has been argued over the past decades among scientists. Although the similarities and contrasts between sleep and epilepsy had been considered, their intertwined nature was not revealed until the nineteenth century. Sleep is recognized as a recurring state of mind and body through alternating brain electrical activities. It is documented that sleep disorders are associated with epilepsy. The origin, suppression, and spread of seizures are affected by sleep. As such, in patients with epilepsy, sleep disorders are a frequent comorbidity. Meanwhile, orexin, a wake-promoting neuropeptide, provides a bidirectional effect on both sleep and epilepsy. Orexin and its cognate receptors, orexin receptor type 1 (OX1R) and type 2 (OX2R), orchestrate their effects by activating various downstream signaling pathways. Although orexin was considered a therapeutic target in insomnia shortly after its discovery, its potential usefulness for psychiatric disorders and epileptic seizures has been suggested in the pre-clinical studies. This review aimed to discuss whether the relationship between sleep, epilepsy, and orexin is clearly reciprocal.
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Affiliation(s)
- Mohammad Sheibani
- Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Razi Drug Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Maryam Shayan
- Experimental Medicine Research Centre, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mina Khalilzadeh
- Experimental Medicine Research Centre, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Centre, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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12
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Nakamoto K, Matsuura W, Tokuyama S. Nicotine suppresses central post-stroke pain via facilitation of descending noradrenergic neuron through activation of orexinergic neuron. Eur J Pharmacol 2023; 943:175518. [PMID: 36706800 DOI: 10.1016/j.ejphar.2023.175518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023]
Abstract
Central post-stroke pain (CPSP) is a type of central neuropathic pain, whose underlying mechanisms remain unknown. We previously reported that bilateral carotid artery occlusion (BCAO)-induced CPSP model mice showed mechanical hypersensitivity and decreased mRNA levels of preproorexin, an orexin precursor, in the hypothalamus. Recently, nicotine was shown to regulate the neuronal activity of orexin in the lateral hypothalamus (LH) and suppress inflammatory and neuropathic pain. In this study, we evaluated whether nicotine could suppress BCAO-induced mechanical allodynia through the activation of orexinergic neurons. Mice were subjected to BCAO for 30 min. Mechanical hypersensitivity was assessed by the von Frey test. BCAO mice showed hypersensitivity to mechanical stimuli three days after BCAO surgery. The intracerebroventricular injection of nicotine suppressed BCAO-induced mechanical hypersensitivity in a dose-dependent manner. These effects were inhibited by α7 or α4β2-nicotinic receptor antagonists. After nicotine injection, the level of c-fos, a neuronal activity marker, increased in the LH and locus coeruleus (LC) of Sham and BCAO mice. Increased number of c-Fos-positive cells partly colocalized with orexin A-positive cells in the LH, as well as tyrosine hydroxylase-positive cells in the LC. Orexinergic neurons project to the LC area. Nicotine-induced antinociception tended to cancel by the pretreatment of SB334867, an orexin receptor1 antagonist into the LC. Intra-LH microinjection of nicotine attenuated BCAO-induced mechanical hypersensitivity. Nicotine-induced antinociception was inhibited by intrathecal pre-treatment with yohimbine, an α2 adrenergic receptor antagonist. These results indicated that nicotine may suppress BCAO-induced mechanical hypersensitivity through the activation of the descending pain control system via orexin neurons.
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Affiliation(s)
- Kazuo Nakamoto
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan
| | - Wataru Matsuura
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan
| | - Shogo Tokuyama
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan.
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13
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Garrido-Suárez BB, Garrido-Valdes M, Garrido G. Reactogenic sleepiness after COVID-19 vaccination. A hypothesis involving orexinergic system linked to inflammatory signals. Sleep Med 2022; 98:79-86. [PMID: 35792321 PMCID: PMC9212783 DOI: 10.1016/j.sleep.2022.06.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/24/2022] [Accepted: 06/14/2022] [Indexed: 11/18/2022]
Abstract
Coronavirus disease 2019 (COVID-19) represents a global healthcare crisis that has led to morbidity and mortality on an unprecedented scale. While studies on COVID-19 vaccines are ongoing, the knowledge about the reactogenic symptoms that can occur after vaccination and its generator mechanisms can be critical for healthcare professionals to improve compliance with the future vaccination campaign. Because sleep and immunity are bidirectionally linked, sleepiness or sleep disturbance side effects reported after some of the COVID-19 vaccines advise an academic research line in the context of physiological or pathological neuroimmune interactions. On the recognized basis of inflammatory regulation of hypothalamic neurons in sickness behavior, we hypothesized that IL-1β, INF-γ and TNF-α pro-inflammatory cytokines inhibit orexinergic neurons promoting sleepiness after peripheral activation of the innate immune system induced by the novel COVID-19 vaccines. In addition, based on knowledge of previous vaccines and disease manifestations of SARS-CoV-2 infection, it also suggests that narcolepsy must be included as potential adverse events of particular interest to consider in pharmacovigilance studies.
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14
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López JM, Carballeira P, Pozo J, León-Espinosa G, Muñoz A. Hypothalamic orexinergic neuron changes during the hibernation of the Syrian hamster. Front Neuroanat 2022; 16:993421. [PMID: 36157325 PMCID: PMC9501701 DOI: 10.3389/fnana.2022.993421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/09/2022] [Indexed: 11/23/2022] Open
Abstract
Hibernation in small mammals is a highly regulated process with periods of torpor involving drops in body temperature and metabolic rate, as well as a general decrease in neural activity, all of which proceed alongside complex brain adaptive changes that appear to protect the brain from extreme hypoxia and low temperatures. All these changes are rapidly reversed, with no apparent brain damage occurring, during the short periods of arousal, interspersed during torpor—characterized by transitory and partial rewarming and activity, including sleep activation, and feeding in some species. The orexins are neuropeptides synthesized in hypothalamic neurons that project to multiple brain regions and are known to participate in the regulation of a variety of processes including feeding behavior, the sleep-wake cycle, and autonomic functions such as brown adipose tissue thermogenesis. Using multiple immunohistochemical techniques and quantitative analysis, we have characterized the orexinergic system in the brain of the Syrian hamster—a facultative hibernator. Our results revealed that orexinergic neurons in this species consisted of a neuronal population restricted to the lateral hypothalamic area, whereas orexinergic fibers distribute throughout the rostrocaudal extent of the brain, particularly innervating catecholaminergic and serotonergic neuronal populations. We characterized the changes of orexinergic cells in the different phases of hibernation based on the intensity of immunostaining for the neuronal activity marker C-Fos and orexin A (OXA). During torpor, we found an increase in C-Fos immunostaining intensity in orexinergic neurons, accompanied by a decrease in OXA immunostaining. These changes were accompanied by a volume reduction and a fragmentation of the Golgi apparatus (GA) as well as a decrease in the colocalization of OXA and the GA marker GM-130. Importantly, during arousal, C-Fos and OXA expression in orexinergic neurons was highest and the structural appearance and the volume of the GA along with the colocalization of OXA/GM-130 reverted to euthermic levels. We discuss the involvement of orexinergic cells in the regulation of mammalian hibernation and, in particular, the possibility that the high activation of orexinergic cells during the arousal stage guides the rewarming as well as the feeding and sleep behaviors characteristic of this phase.
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Affiliation(s)
- Jesús M. López
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Paula Carballeira
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Javier Pozo
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Gonzalo León-Espinosa
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-Centro de Estudios Universitarios (CEU), Madrid, Spain
| | - Alberto Muñoz
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica (CTB), Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- *Correspondence: Alberto Muñoz,
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15
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Sciolino NR, Hsiang M, Mazzone CM, Wilson LR, Plummer NW, Amin J, Smith KG, McGee CA, Fry SA, Yang CX, Powell JM, Bruchas MR, Kravitz AV, Cushman JD, Krashes MJ, Cui G, Jensen P. Natural locus coeruleus dynamics during feeding. SCIENCE ADVANCES 2022; 8:eabn9134. [PMID: 35984878 PMCID: PMC9390985 DOI: 10.1126/sciadv.abn9134] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Recent data demonstrate that noradrenergic neurons of the locus coeruleus (LC-NE) are required for fear-induced suppression of feeding, but the role of endogenous LC-NE activity in natural, homeostatic feeding remains unclear. Here, we found that LC-NE activity was suppressed during food consumption, and the magnitude of this neural response was attenuated as mice consumed more pellets throughout the session, suggesting that LC responses to food are modulated by satiety state. Visual-evoked LC-NE activity was also attenuated in sated mice, suggesting that satiety state modulates LC-NE encoding of multiple behavioral states. We also found that food intake could be attenuated by brief or longer durations of LC-NE activation. Last, we found that activation of the LC to the lateral hypothalamus pathway suppresses feeding and enhances avoidance and anxiety-like responding. Our findings suggest that LC-NE neurons modulate feeding by integrating both external cues (e.g., anxiogenic environmental cues) and internal drives (e.g., satiety).
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Affiliation(s)
- Natale R. Sciolino
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Madeline Hsiang
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Christopher M. Mazzone
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Leslie R. Wilson
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Nicholas W. Plummer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Jaisal Amin
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Kathleen G. Smith
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Christopher A. McGee
- Comparative Medicine, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Sydney A. Fry
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Cindy X. Yang
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Jeanne M. Powell
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Michael R. Bruchas
- Departments of Anesthesiology and Pharmacology, Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
| | | | - Jesse D. Cushman
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Michael J. Krashes
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA
| | - Guohong Cui
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Patricia Jensen
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
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16
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Villano I, La Marra M, Di Maio G, Monda V, Chieffi S, Guatteo E, Messina G, Moscatelli F, Monda M, Messina A. Physiological Role of Orexinergic System for Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:8353. [PMID: 35886210 PMCID: PMC9323672 DOI: 10.3390/ijerph19148353] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/03/2022] [Accepted: 07/05/2022] [Indexed: 02/06/2023]
Abstract
Orexins, or hypocretins, are excitatory neuropeptides involved in the regulation of feeding behavior and the sleep and wakefulness states. Since their discovery, several lines of evidence have highlighted that orexin neurons regulate a great range of physiological functions, giving it the definition of a multitasking system. In the present review, we firstly describe the mechanisms underlining the orexin system and their interactions with the central nervous system (CNS). Then, the system's involvement in goal-directed behaviors, sleep/wakefulness state regulation, feeding behavior and energy homeostasis, reward system, and aging and neurodegenerative diseases are described. Advanced evidence suggests that the orexin system is crucial for regulating many physiological functions and could represent a promising target for therapeutical approaches to obesity, drug addiction, and emotional stress.
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Affiliation(s)
- Ines Villano
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Marco La Marra
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Girolamo Di Maio
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Vincenzo Monda
- Department of Movement Sciences and Wellbeing, University of Naples “Parthenope”, 80138 Naples, Italy; (V.M.); (E.G.)
| | - Sergio Chieffi
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Ezia Guatteo
- Department of Movement Sciences and Wellbeing, University of Naples “Parthenope”, 80138 Naples, Italy; (V.M.); (E.G.)
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, 71100 Foggia, Italy; (G.M.); (F.M.)
| | - Fiorenzo Moscatelli
- Department of Clinical and Experimental Medicine, University of Foggia, 71100 Foggia, Italy; (G.M.); (F.M.)
| | - Marcellino Monda
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Antonietta Messina
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
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17
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Roles of Neuropeptides in Sleep-Wake Regulation. Int J Mol Sci 2022; 23:ijms23094599. [PMID: 35562990 PMCID: PMC9103574 DOI: 10.3390/ijms23094599] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/31/2022] [Accepted: 04/19/2022] [Indexed: 12/04/2022] Open
Abstract
Sleep and wakefulness are basic behavioral states that require coordination between several brain regions, and they involve multiple neurochemical systems, including neuropeptides. Neuropeptides are a group of peptides produced by neurons and neuroendocrine cells of the central nervous system. Like traditional neurotransmitters, neuropeptides can bind to specific surface receptors and subsequently regulate neuronal activities. For example, orexin is a crucial component for the maintenance of wakefulness and the suppression of rapid eye movement (REM) sleep. In addition to orexin, melanin-concentrating hormone, and galanin may promote REM sleep. These results suggest that neuropeptides play an important role in sleep–wake regulation. These neuropeptides can be divided into three categories according to their effects on sleep–wake behaviors in rodents and humans. (i) Galanin, melanin-concentrating hormone, and vasoactive intestinal polypeptide are sleep-promoting peptides. It is also noticeable that vasoactive intestinal polypeptide particularly increases REM sleep. (ii) Orexin and neuropeptide S have been shown to induce wakefulness. (iii) Neuropeptide Y and substance P may have a bidirectional function as they can produce both arousal and sleep-inducing effects. This review will introduce the distribution of various neuropeptides in the brain and summarize the roles of different neuropeptides in sleep–wake regulation. We aim to lay the foundation for future studies to uncover the mechanisms that underlie the initiation, maintenance, and end of sleep–wake states.
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18
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Mavanji V, Pomonis B, Kotz CM. Orexin, serotonin, and energy balance. WIREs Mech Dis 2022; 14:e1536. [PMID: 35023323 PMCID: PMC9286346 DOI: 10.1002/wsbm.1536] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 12/02/2022]
Abstract
The lateral hypothalamus is critical for the control of ingestive behavior and spontaneous physical activity (SPA), as lesion or stimulation of this region alters these behaviors. Evidence points to lateral hypothalamic orexin neurons as modulators of feeding and SPA. These neurons affect a broad range of systems, and project to multiple brain regions such as the dorsal raphe nucleus, which contains serotoninergic neurons (DRN) important to energy homeostasis. Physical activity is comprised of intentional exercise and SPA. These are opposite ends of a continuum of physical activity intensity and structure. Non‐goal‐oriented behaviors, such as fidgeting, standing, and ambulating, constitute SPA in humans, and reflect a propensity for activity separate from intentional activity, such as high‐intensity voluntary exercise. In animals, SPA is activity not influenced by rewards such as food or a running wheel. Spontaneous physical activity in humans and animals burns calories and could theoretically be manipulated pharmacologically to expend calories and protect against obesity. The DRN neurons receive orexin inputs, and project heavily onto cortical and subcortical areas involved in movement, feeding and energy expenditure (EE). This review discusses the function of hypothalamic orexin in energy‐homeostasis, the interaction with DRN serotonin neurons, and the role of this orexin‐serotonin axis in regulating food intake, SPA, and EE. In addition, we discuss possible brain areas involved in orexin–serotonin cross‐talk; the role of serotonin receptors, transporters and uptake‐inhibitors in the pathogenesis and treatment of obesity; animal models of obesity with impaired serotonin‐function; single‐nucleotide polymorphisms in the serotonin system and obesity; and future directions in the orexin–serotonin field. This article is categorized under:Metabolic Diseases > Molecular and Cellular Physiology
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Affiliation(s)
- Vijayakumar Mavanji
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
| | - Brianna Pomonis
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
| | - Catherine M Kotz
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA.,Geriatric Research Education and Clinical Center, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
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19
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Vaseghi S, Zarrabian S, Haghparast A. Reviewing the role of the orexinergic system and stressors in modulating mood and reward-related behaviors. Neurosci Biobehav Rev 2021; 133:104516. [PMID: 34973302 DOI: 10.1016/j.neubiorev.2021.104516] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 01/22/2023]
Abstract
In this review study, we aimed to introduce the orexinergic system as an important signaling pathway involved in a variety of cognitive functions such as memory, motivation, and reward-related behaviors. This study focused on the role of orexinergic system in modulating reward-related behavior, with or without the presence of stressors. Cross-talk between the reward system and orexinergic signaling was also investigated, especially orexinergic signaling in the ventral tegmental area (VTA), the nucleus accumbens (NAc), and the hippocampus. Furthermore, we discussed the role of the orexinergic system in modulating mood states and mental illnesses such as depression, anxiety, panic, and posttraumatic stress disorder (PTSD). Here, we narrowed down our focus on the orexinergic signaling in three brain regions: the VTA, NAc, and the hippocampus (CA1 region and dentate gyrus) for their prominent role in reward-related behaviors and memory. It was concluded that the orexinergic system is critically involved in reward-related behavior and significantly alters stress responses and stress-related psychiatric and mood disorders.
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Affiliation(s)
- Salar Vaseghi
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran
| | - Shahram Zarrabian
- Department of Anatomical Sciences & Cognitive Neuroscience, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.
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20
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Iorio R, Papi C. Neuromyelitis optica, aquaporin-4 antibodies, and neuroendocrine disorders. HANDBOOK OF CLINICAL NEUROLOGY 2021; 181:173-186. [PMID: 34238456 DOI: 10.1016/b978-0-12-820683-6.00013-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system that preferentially affects the optic nerve and the spinal cord. In around 80% of NMO patients, autoantibodies binding to aquaporin-4 (AQP4) are detected. AQP4-IgG unifies a spectrum of disorders (NMOSD) that include not only optic neuritis, longitudinally extensive transverse myelitis but also syndromes caused by lesion of the diencephalic region and the circumventricular organs (CVOs). The distinctive immunopathological characteristics of NMOSD lesions, occurring in regions where AQP4 is highly expressed, supports a central role for AQP4-IgG in disease pathogenesis. AQP4 expression is concentrated in CVOs and in the hypothalamus, mainly in the dorsal hypothalamic area, dorsomedial hypothalamic nucleus and suprachiasmatic nucleus. Several neuroendocrine disorders caused by inflammatory lesions involving the diencephalic region have been described in patients with NMOSD, including syndrome of inappropriate antidiuresis, sleep disorders, and other endocrinopathies caused by hypothalamic injury. Focus of this chapter is the involvement of hypothalamus and CVOs in AQP4 autoimmunity.
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Affiliation(s)
- Raffaele Iorio
- Neurology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, and Università Cattolica del Sacro Cuore, Rome, Italy
| | - Claudia Papi
- Neurology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, and Università Cattolica del Sacro Cuore, Rome, Italy
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21
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van Galen KA, Ter Horst KW, Serlie MJ. Serotonin, food intake, and obesity. Obes Rev 2021; 22:e13210. [PMID: 33559362 PMCID: PMC8243944 DOI: 10.1111/obr.13210] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 12/16/2022]
Abstract
The role of serotonin in food intake has been studied for decades. Food intake is mainly regulated by two brain circuitries: (i) the homeostatic circuitry, which matches energy intake to energy expenditure, and (ii) the hedonic circuitry, which is involved in rewarding and motivational aspects of energy consumption. In the homeostatic circuitry, serotonergic signaling contributes to the integration of metabolic signals that convey the body's energy status and facilitates the ability to suppress food intake when homeostatic needs have been met. In the hedonic circuitry, serotonergic signaling may reduce reward-related, motivational food consumption. In contrast, peripherally acting serotonin promotes energy absorption and storage. Disturbed serotonergic signaling is associated with obesity, emphasizing the importance to understand the role of serotonergic signaling in food intake. However, unraveling the serotonin-mediated regulation of food intake is complex, as the effects of serotonergic signaling in different brain regions depend on the regional expression of serotonin receptor subtypes and downstream effects via connections to other brain regions. We therefore provide an overview of the effects of serotonergic signaling in brain regions of the homeostatic and hedonic regulatory systems on food intake. Furthermore, we discuss the disturbances in serotonergic signaling in obesity and its potential therapeutic implications.
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Affiliation(s)
- Katy A van Galen
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Kasper W Ter Horst
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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22
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Regulatory Role of Orexin in the Antistress Effect of "Press Tack Needle" Acupuncture Treatment. Healthcare (Basel) 2021; 9:healthcare9050503. [PMID: 33925438 PMCID: PMC8146164 DOI: 10.3390/healthcare9050503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 11/18/2022] Open
Abstract
The aim of this research was to investigate the antistress effect of press tack needle (PTN) acupuncture treatment using rats with social isolation stress (SIS). Rats were divided into non-stress group (Grouped+sham), stress group (SIS+sham), and PTN-treated SIS group (SIS+PTN). Rats in the SIS+PTN and SIS+sham groups were housed alone for eight days. For the SIS+PTN group, a PTN (length, 0.3 or 1.2 mm) was fixed on the GV20 acupoint on day 7. We measured stress behavior based on the time the rats showed aggressive behavior and the levels of plasma corticosterone and orexin A on day 8. In addition, the orexin-1 receptor or orexin-2 receptor antagonist was administered to rats that were exposed to SIS. The duration of aggressive behavior was significantly prolonged in the SIS+sham group, and the prolonged duration was inhibited in the SIS+PTN (1.2 mm) group. The levels of plasma corticosterone and orexin A were significantly increased in the SIS+sham group; however, these increases were inhibited in the SIS+PTN group. The aggressive behavior was significantly reduced after the orexin-2 receptor antagonist was administered. These findings suggest that PTN treatment at GV20 may have an antistress effect, and the control of orexin is a mechanism underlying this phenomenon.
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23
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Concetti C, Burdakov D. Orexin/Hypocretin and MCH Neurons: Cognitive and Motor Roles Beyond Arousal. Front Neurosci 2021; 15:639313. [PMID: 33828450 PMCID: PMC8019792 DOI: 10.3389/fnins.2021.639313] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/01/2021] [Indexed: 02/01/2023] Open
Abstract
The lateral hypothalamus (LH) is classically implicated in sleep-wake control. It is the main source of orexin/hypocretin and melanin-concentrating hormone (MCH) neuropeptides in the brain, which have been both implicated in arousal state switching. These neuropeptides are produced by non-overlapping LH neurons, which both project widely throughout the brain, where release of orexin and MCH activates specific postsynaptic G-protein-coupled receptors. Optogenetic manipulations of orexin and MCH neurons during sleep indicate that they promote awakening and REM sleep, respectively. However, recordings from orexin and MCH neurons in awake, moving animals suggest that they also act outside sleep/wake switching. Here, we review recent studies showing that both orexin and MCH neurons can rapidly (sub-second-timescale) change their firing when awake animals experience external stimuli, or during self-paced exploration of objects and places. However, the sensory-behavioral correlates of orexin and MCH neural activation can be quite different. Orexin neurons are generally more dynamic, with about 2/3rds of them activated before and during self-initiated running, and most activated by sensory stimulation across sensory modalities. MCH neurons are activated in a more select manner, for example upon self-paced investigation of novel objects and by certain other novel stimuli. We discuss optogenetic and chemogenetic manipulations of orexin and MCH neurons, which combined with pharmacological blockade of orexin and MCH receptors, imply that these rapid LH dynamics shape fundamental cognitive and motor processes due to orexin and MCH neuropeptide actions in the awake brain. Finally, we contemplate whether the awake control of psychomotor brain functions by orexin and MCH are distinct from their “arousal” effects.
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Affiliation(s)
- Cristina Concetti
- Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
| | - Denis Burdakov
- Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
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Blockade of orexin receptors in the ventral tegmental area reduced the extinction period of the lateral hypothalamic-induced conditioned place preference in rats. Behav Pharmacol 2020; 32:54-61. [PMID: 33399296 DOI: 10.1097/fbp.0000000000000602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The orexinergic connection between the lateral hypothalamus (LH) and the ventral tegmental area (VTA) is involved in modulating the reward circuit. The conditioned place preference (CPP) can be induced by microinjection of carbachol, a cholinergic agonist, into the LH. The current research was conducted to understand whether intra-VTA orexin receptors (OXRs) could influence the duration of the extinction period or maintenance of the intra-LH carbachol-induced CPP. To this end, the rats unilaterally received intra-LH carbachol (250 nM) within a 3-day conditioning period. Animals that have already passed the conditioning test were unilaterally administered by intra-VTA microinjection of SB334867, an OX1R antagonist, or TCS OX2 29, an OX2R antagonist during the extinction phase of the LH stimulation-induced CPP. For the first time, our data indicated that daily intra-VTA administration of either SB334867 (30 nM) or TCS OX2 29 (10 and 30 nM) during the extinction period decreased the maintenance of intra-LH carbachol-induced CPP. In conclusion, OXRs in the VTA play crucial roles in the maintenance of reward processes.
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Berteotti C, Liguori C, Pace M. Dysregulation of the orexin/hypocretin system is not limited to narcolepsy but has far-reaching implications for neurological disorders. Eur J Neurosci 2020; 53:1136-1154. [PMID: 33290595 DOI: 10.1111/ejn.15077] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 12/23/2022]
Abstract
Neuropeptides orexin A and B (OX-A/B, also called hypocretin 1 and 2) are released selectively by a population of neurons which projects widely into the entire central nervous system but is localized in a restricted area of the tuberal region of the hypothalamus, caudal to the paraventricular nucleus. The OX system prominently targets brain structures involved in the regulation of wake-sleep state switching, and also orchestrates multiple physiological functions. The degeneration and dysregulation of the OX system promotes narcoleptic phenotypes both in humans and animals. Hence, this review begins with the already proven involvement of OX in narcolepsy, but it mainly discusses the new pre-clinical and clinical insights of the role of OX in three major neurological disorders characterized by sleep impairment which have been recently associated with OX dysfunction, such as Alzheimer's disease, stroke and Prader Willi syndrome, and have been emerged over the past 10 years to be strongly associated with the OX dysfunction and should be more considered in the future. In the light of the impairment of the OX system in these neurological disorders, it is conceivable to speculate that the integrity of the OX system is necessary for a healthy functioning body.
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Affiliation(s)
- Chiara Berteotti
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Claudio Liguori
- Sleep Medicine Centre, Neurology Unit, University Hospital Tor Vergata, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Marta Pace
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
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Beuckmann CT, Ueno T, Nakagawa M, Suzuki M, Akasofu S. Preclinical in vivo characterization of lemborexant (E2006), a novel dual orexin receptor antagonist for sleep/wake regulation. Sleep 2020; 42:5421821. [PMID: 30923834 PMCID: PMC6559177 DOI: 10.1093/sleep/zsz076] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/26/2019] [Indexed: 12/22/2022] Open
Abstract
Study Objectives To present results from in vivo studies underlying the preclinical development of lemborexant (E2006), a novel dual orexin (hypocretin) receptor antagonist for sleep/wake regulation. Methods Rodent (wild-type rats and wild-type and orexin neuron-deficient [orexin/ataxin-3 Tg/+] mice) studies were performed to evaluate the effects of single-dose oral lemborexant (1–300 mg/kg) on orexin-induced increases in plasma adrenocorticotropic hormone (ACTH), locomotor activity, vigilance state measures (wakefulness, nonrapid eye movement [non-REM] sleep, rapid eye movement [REM] sleep), ethanol-induced anesthesia, and motor coordination, and the effects of multiple-dose oral lemborexant (30 mg/kg) on vigilance state measures. Active comparators were almorexant and zolpidem. Pharmacokinetics were assessed after single-dose lemborexant in mice and rats. Results Lemborexant prevented the orexin-promoted increase in ACTH in rats, therefore demonstrating inhibition of the orexin signaling pathway. Furthermore, lemborexant promoted sleep in wild-type mice and rats. Lemborexant promoted REM and non-REM sleep at an equal rate (there was no change in the REM sleep ratio). In contrast, zolpidem reduced REM sleep. The sleep-promoting effect of lemborexant was mediated via the orexin-peptide signaling pathway as demonstrated by a lack of sleep promotion in orexin neuron-deficient mice. Chronic dosing was not associated with a change in effect size or sleep architecture immediately postdosing. Lemborexant did not increase the sedative effects of ethanol or impair motor coordination, showing good safety margin in animals. Pharmacokinetic/pharmacodynamic data for mice and rats were well aligned. Conclusions These findings supported further clinical evaluation (ongoing at this time) of lemborexant as a potential candidate for treating insomnia and other sleep disorders.
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Affiliation(s)
| | - Takashi Ueno
- Drug Metabolism and Pharmacokinetics, Eisai Co., Ltd., Tsukuba, Japan
| | - Makoto Nakagawa
- Neurology Business Group, Discovery, Eisai Co., Ltd., Tsukuba, Japan
| | - Michiyuki Suzuki
- Pharmaceutical Regulatory Affairs Department, Marketing Authorization Group, EA Pharma Co., Ltd., Tokyo, Japan
| | - Shigeru Akasofu
- Neurology Business Group, Discovery, Eisai Co., Ltd., Tsukuba, Japan
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Adeghate E, Lotfy M, D'Souza C, Alseiari SM, Alsaadi AA, Qahtan SA. Hypocretin/orexin modulates body weight and the metabolism of glucose and insulin. Diabetes Metab Res Rev 2020; 36:e3229. [PMID: 31655012 DOI: 10.1002/dmrr.3229] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 08/16/2019] [Accepted: 10/06/2019] [Indexed: 12/18/2022]
Abstract
The hypocretin/orexin (Hcrt/orexin) unit affects the functions of the nervous, cardiovascular, gastrointestinal, and reproductive systems. Hcrt/orexin ligands and receptors have been localized to different parts of the central and peripheral nervous systems, cerebrospinal fluid and blood, exocrine (pancreas, salivary, lacrimal) as well as endocrine (pancreatic islets, pituitary, adrenal) glands. Several factors including stress, glucagon-like peptide-1 agonists, glutamate, nicotine, glucose, and hypoglycaemia stimulate the expression of Hcrt/orexin system, but it is inhibited by ageing, bone morphogenetic protein, hypoxia/hypercapnia, melanocortin receptor accessory protein 2, and glucagon. Literature reports show that Hcrt/orexin can significantly increase insulin secretion from normal and diabetic rat pancreata. Hcrt/orexin decreases blood glucose concentration and reduces insulin resistance partly via increased tissue expression of glucose transporter type 4. It reduces obesity by increasing browning of fat cells and energy expenditure. Taken together, Hcrt/orexin modulates obesity and the metabolism of glucose and insulin. The Hcrt/orexin system may thus be a target in the development of new therapies for the treatment of diabetes mellitus.
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Affiliation(s)
- Ernest Adeghate
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Mohamed Lotfy
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Crystal D'Souza
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Saleh Meqbel Alseiari
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Abdulla Ali Alsaadi
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Saif Abdo Qahtan
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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Li SB, de Lecea L. The hypocretin (orexin) system: from a neural circuitry perspective. Neuropharmacology 2020; 167:107993. [PMID: 32135427 DOI: 10.1016/j.neuropharm.2020.107993] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/23/2020] [Accepted: 02/05/2020] [Indexed: 12/11/2022]
Abstract
Hypocretin/orexin neurons are distributed restrictively in the hypothalamus, a brain region known to orchestrate diverse functions including sleep, reward processing, food intake, thermogenesis, and mood. Since the hypocretins/orexins were discovered more than two decades ago, extensive studies have accumulated concrete evidence showing the pivotal role of hypocretin/orexin in diverse neural modulation. New method of viral-mediated tracing system offers the possibility to map the monosynaptic inputs and detailed anatomical connectivity of Hcrt neurons. With the development of powerful research techniques including optogenetics, fiber-photometry, cell-type/pathway specific manipulation and neuronal activity monitoring, as well as single-cell RNA sequencing, the details of how hypocretinergic system execute functional modulation of various behaviors are coming to light. In this review, we focus on the function of neural pathways from hypocretin neurons to target brain regions. Anatomical and functional inputs to hypocretin neurons are also discussed. We further briefly summarize the development of pharmaceutical compounds targeting hypocretin signaling. This article is part of the special issue on Neuropeptides.
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Affiliation(s)
- Shi-Bin Li
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA, 94305, USA.
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA, 94305, USA.
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Scammell TE, Jackson AC, Franks NP, Wisden W, Dauvilliers Y. Histamine: neural circuits and new medications. Sleep 2019; 42:5099478. [PMID: 30239935 PMCID: PMC6335869 DOI: 10.1093/sleep/zsy183] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Indexed: 12/12/2022] Open
Abstract
Histamine was first identified in the brain about 50 years ago, but only in the last few years have researchers gained an understanding of how it regulates sleep/wake behavior. We provide a translational overview of the histamine system, from basic research to new clinical trials demonstrating the usefulness of drugs that enhance histamine signaling. The tuberomammillary nucleus is the sole neuronal source of histamine in the brain, and like many of the arousal systems, histamine neurons diffusely innervate the cortex, thalamus, and other wake-promoting brain regions. Histamine has generally excitatory effects on target neurons, but paradoxically, histamine neurons may also release the inhibitory neurotransmitter GABA. New research demonstrates that activity in histamine neurons is essential for normal wakefulness, especially at specific circadian phases, and reducing activity in these neurons can produce sedation. The number of histamine neurons is increased in narcolepsy, but whether this affects brain levels of histamine is controversial. Of clinical importance, new compounds are becoming available that enhance histamine signaling, and clinical trials show that these medications reduce sleepiness and cataplexy in narcolepsy.
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Affiliation(s)
- Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT
| | - Nicholas P Franks
- Department of Life Sciences and UK Dementia Research Institute, Imperial College London, UK
| | - William Wisden
- Department of Life Sciences and UK Dementia Research Institute, Imperial College London, UK
| | - Yves Dauvilliers
- Centre National de Référence Narcolepsie Hypersomnies, Unité des Troubles du Sommeil, Service de Neurologie, Hôpital Gui-de-Chauliac, Université Montpellier, INSERM, Montpellier, France
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Transgenic Archaerhodopsin-3 Expression in Hypocretin/Orexin Neurons Engenders Cellular Dysfunction and Features of Type 2 Narcolepsy. J Neurosci 2019; 39:9435-9452. [PMID: 31628177 DOI: 10.1523/jneurosci.0311-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 02/08/2023] Open
Abstract
Narcolepsy, characterized by excessive daytime sleepiness, is associated with dysfunction of the hypothalamic hypocretin/orexin (Hcrt) system, either due to extensive loss of Hcrt cells (Type 1, NT1) or hypothesized Hcrt signaling impairment (Type 2, NT2). Accordingly, efforts to recapitulate narcolepsy-like symptoms in mice have involved ablating these cells or interrupting Hcrt signaling. Here, we describe orexin/Arch mice, in which a modified archaerhodopsin-3 gene was inserted downstream of the prepro-orexin promoter, resulting in expression of the yellow light-sensitive Arch-3 proton pump specifically within Hcrt neurons. Histological examination along with ex vivo and in vivo electrophysiological recordings of male and female orexin/Arch mice demonstrated silencing of Hcrt neurons when these cells were photoilluminated. However, high expression of the Arch transgene affected cellular and physiological parameters independent of photoillumination. The excitability of Hcrt neurons was reduced, and both circadian and metabolic parameters were perturbed in a subset of orexin/Arch mice that exhibited high levels of Arch expression. Orexin/Arch mice also had increased REM sleep under baseline conditions but did not exhibit cataplexy, a sudden loss of muscle tone during wakefulness characteristic of NT1. These aberrations resembled some aspects of mouse models with Hcrt neuron ablation, yet the number of Hcrt neurons in orexin/Arch mice was not reduced. Thus, orexin/Arch mice may be useful to investigate Hcrt system dysfunction when these neurons are intact, as is thought to occur in narcolepsy without cataplexy (NT2). These results also demonstrate the utility of extended phenotypic screening of transgenic models when specific neural circuits have been manipulated.SIGNIFICANCE STATEMENT Optogenetics has become an invaluable tool for functional dissection of neural circuitry. While opsin expression is often achieved by viral injection, stably integrated transgenes offer some practical advantages. Here, we demonstrate successful transgenic expression of an inhibitory opsin in hypocretin/orexin neurons, which are thought to promote or maintain wakefulness. Both brief and prolonged illumination resulted in inhibition of these neurons and induced sleep. However, even in the absence of illumination, these cells exhibited altered electrical characteristics, particularly when transgene expression was high. These aberrant properties affected metabolism and sleep, resulting in a phenotype reminiscent of the narcolepsy Type 2, a sleep disorder for which no good animal model currently exists.
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Ritter S, Li AJ, Wang Q. Hindbrain glucoregulatory mechanisms: Critical role of catecholamine neurons in the ventrolateral medulla. Physiol Behav 2019; 208:112568. [PMID: 31173784 PMCID: PMC7015674 DOI: 10.1016/j.physbeh.2019.112568] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 12/29/2022]
Abstract
Glucose is the required metabolic substrate for the brain. Yet the brain stores very little glucose. Therefore, the brain continuously monitors glucose availability to detect hypoglycemia and to mobilize system-wide responses to protect and restore euglycemia. Catecholamine (CA) neurons in the hindbrain are critical elements of the brain's glucoregulatory mechanisms. They project widely throughout the brain and spinal cord, innervating sites controlling behavioral, endocrine and visceral responses. Hence, CA neurons are capable of triggering a rapid, coordinated and multifaceted response to glucose challenge. This article reviews experimental data that has begun to elucidate the importance of CA neurons for glucoregulation, the functions of specific CA subpopulations in the ventrolateral medulla, and the extended circuitry through which they engage other levels of the nervous system to accomplish their essential glucoregulatory task. Hopefully, this review also suggests the vast amount of work yet to be done in this area and the justification for engaging in that effort.
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Affiliation(s)
- Sue Ritter
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, United States of America.
| | - Ai-Jun Li
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, United States of America
| | - Qing Wang
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, United States of America
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Comeras LB, Herzog H, Tasan RO. Neuropeptides at the crossroad of fear and hunger: a special focus on neuropeptide Y. Ann N Y Acad Sci 2019; 1455:59-80. [PMID: 31271235 PMCID: PMC6899945 DOI: 10.1111/nyas.14179] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/15/2019] [Accepted: 06/03/2019] [Indexed: 12/11/2022]
Abstract
Survival in a natural environment forces an individual into constantly adapting purposive behavior. Specified interoceptive neurons monitor metabolic and physiological balance and activate dedicated brain circuits to satisfy essential needs, such as hunger, thirst, thermoregulation, fear, or anxiety. Neuropeptides are multifaceted, central components within such life‐sustaining programs. For instance, nutritional depletion results in a drop in glucose levels, release of hormones, and activation of hypothalamic and brainstem neurons. These neurons, in turn, release several neuropeptides that increase food‐seeking behavior and promote food intake. Similarly, internal and external threats activate neuronal pathways of avoidance and defensive behavior. Interestingly, specific nuclei of the hypothalamus and extended amygdala are activated by both hunger and fear. Here, we introduce the relevant neuropeptides and describe their function in feeding and emotional‐affective behaviors. We further highlight specific pathways and microcircuits, where neuropeptides may interact to identify prevailing homeostatic needs and direct respective compensatory behaviors. A specific focus will be on neuropeptide Y, since it is known for its pivotal role in metabolic and emotional pathways. We hypothesize that the orexigenic and anorexigenic properties of specific neuropeptides are related to their ability to inhibit fear and anxiety.
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Affiliation(s)
- Lucas B Comeras
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Herbert Herzog
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Ramon O Tasan
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
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Goh GH, Maloney SK, Mark PJ, Blache D. Episodic Ultradian Events-Ultradian Rhythms. BIOLOGY 2019; 8:E15. [PMID: 30875767 PMCID: PMC6466064 DOI: 10.3390/biology8010015] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/24/2019] [Accepted: 03/09/2019] [Indexed: 11/16/2022]
Abstract
In the fast lane of chronobiology, ultradian events are short-term rhythms that have been observed since the beginning of modern biology and were quantified about a century ago. They are ubiquitous in all biological systems and found in all organisms, from unicellular organisms to mammals, and from single cells to complex biological functions in multicellular animals. Since these events are aperiodic and last for a few minutes to a few hours, they are better classified as episodic ultradian events (EUEs). Their origin is unclear. However, they could have a molecular basis and could be controlled by hormonal inputs-in vertebrates, they originate from the activity of the central nervous system. EUEs are receiving increasing attention but their aperiodic nature requires specific sampling and analytic tools. While longer scale rhythms are adaptations to predictable changes in the environment, in theory, EUEs could contribute to adaptation by preparing organisms and biological functions for unpredictability.
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Affiliation(s)
- Grace H Goh
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia.
| | - Shane K Maloney
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia.
| | - Peter J Mark
- School of Human Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia.
| | - Dominique Blache
- School of Agriculture and Environment and UWA Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia.
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Burdakov D. Reactive and predictive homeostasis: Roles of orexin/hypocretin neurons. Neuropharmacology 2018; 154:61-67. [PMID: 30347195 DOI: 10.1016/j.neuropharm.2018.10.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/14/2018] [Accepted: 10/16/2018] [Indexed: 11/30/2022]
Abstract
Homeostasis is the maintenance of a healthy physiological equilibrium in a changing world. Reactive (feedback, counter-regulatory) and predictive (feedforward, anticipatory) homeostatic control strategies are both important for survival. For example, in energy homeostasis, the pancreas reacts to ingested glucose by releasing insulin, whereas the brain prepares the body for ingestion through anticipatory salivation based on food-associated cues. Reactive control is largely innate, whereas predictive control is often acquired or modified through associative learning, though some important predictive control strategies are innate, e.g. avoidance of fox scent in mice that never met a fox. Traditionally, the hypothalamus has been viewed as a reactive controller, sensing deviations from homeostasis to elicit counter-regulatory responses, while "higher" areas such as the cortex have been viewed as predictive controllers. However, experimental evidence argues against such neuroanatomical segregation: for example, receptors for internal homeostatic indicators are found throughout the brain, while key interoceptive hypothalamic cells also rapidly sense external cues. Here a model is proposed where the brain-wide-projecting, non-neuroendocrine, neurons of the hypothalamus, exemplified by orexin/hypocretin neurons, function as "brain government" systems that convert integrated internal and external information into reactive and predictive autonomic, cognitive, and behavioural adaptations that ensure homeostasis. Like regions of a country without a government, individual brain regions can function normally without hypothalamic guidance, but these functions are uncoordinated, producing mismatch between supply and demand of arousal, and derailing decision-making as seen in orexin-deficient narcolepsy. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Denis Burdakov
- Swiss Federal Institute of Technology / ETH Zürich, D-HEST, Institute for Neuroscience, Schorenstrasse 16, Schwerzenbach 8603, Switzerland.
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Azeez IA, Del Gallo F, Cristino L, Bentivoglio M. Daily Fluctuation of Orexin Neuron Activity and Wiring: The Challenge of "Chronoconnectivity". Front Pharmacol 2018; 9:1061. [PMID: 30319410 PMCID: PMC6167434 DOI: 10.3389/fphar.2018.01061] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/03/2018] [Indexed: 12/12/2022] Open
Abstract
In the heterogeneous hub represented by the lateral hypothalamus, neurons containing the orexin/hypocretin peptides play a key role in vigilance state transitions and wakefulness stability, energy homeostasis, and other functions relevant for motivated behaviors. Orexin neurons, which project widely to the neuraxis, are innervated by multiple extra- and intra-hypothalamic sources. A key property of the adaptive capacity of orexin neurons is represented by daily variations of activity, which is highest in the period of the animal’s activity and wakefulness. These sets of data are here reviewed. They concern the discharge profile during the sleep/wake cycle, spontaneous Fos induction, peptide synthesis and release reflected by immunostaining intensity and peptide levels in the cerebrospinal fluid as well as postsynaptic effects. At the synaptic level, adaptive capacity of orexin neurons subserved by remodeling of excitatory and inhibitory inputs has been shown in response to changes in the nutritional status and prolonged wakefulness. The present review wishes to highlight that synaptic plasticity in the wiring of orexin neurons also occurs in unperturbed conditions and could account for diurnal variations of orexin neuron activity. Data in zebrafish larvae have shown rhythmic changes in the density of inhibitory innervation of orexin dendrites in relation to vigilance states. Recent findings in mice have indicated a diurnal reorganization of the excitatory/inhibitory balance in the perisomatic innervation of orexin neurons. Taken together these sets of data point to “chronoconnectivity,” i.e., a synaptic rearrangement of inputs to orexin neurons over the course of the day in relation to sleep and wake states. This opens questions on the underlying circadian and homeostatic regulation and on the involved players at synaptic level, which could implicate dual transmitters, cytoskeletal rearrangements, hormonal regulation, as well as surrounding glial cells and extracellular matrix. Furthermore, the question arises of a “chronoconnectivity” in the wiring of other neuronal cell groups of the sleep-wake-regulatory network, many of which are characterized by variations of their firing rate during vigilance states.
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Affiliation(s)
- Idris A Azeez
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Federico Del Gallo
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | | | - Marina Bentivoglio
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,National Institute of Neuroscience, Verona Unit, Verona, Italy
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Activation of lateral hypothalamic group III metabotropic glutamate receptors suppresses cocaine-seeking following abstinence and normalizes drug-associated increases in excitatory drive to orexin/hypocretin cells. Neuropharmacology 2018; 154:22-33. [PMID: 30253175 DOI: 10.1016/j.neuropharm.2018.09.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/18/2018] [Accepted: 09/21/2018] [Indexed: 12/22/2022]
Abstract
The perifornical/lateral hypothalamic area (LHA) orexin (hypocretin) system is involved in drug-seeking behavior elicited by drug-associated stimuli. Cocaine exposure is associated with presynaptic plasticity at LHA orexin cells such that excitatory input to orexin cells is enhanced acutely and into withdrawal. These changes may augment orexin cell reactivity to drug-related cues during abstinence and contribute to relapse-like behavior. Studies in hypothalamic slices from drug-naïve animals indicate that agonism of group III metabotropic glutamate receptors (mGluRs) reduces presynaptic glutamate release onto orexin cells. Therefore, we examined the group III mGluR system as a potential target to reduce orexin cell excitability in-vivo, including in animals with cocaine experience. First, we verified that group III mGluRs regulate orexin cell activity in behaving animals by showing that intra-LHA infusions of the selective agonist L-(+)-2-Amino-4-phosphonobutyric acid (L-AP4) reduces c-fos expression in orexin cells following 24 h food deprivation. Next, we extended these findings to show that intra-LHA L-AP4 infusions reduced discriminative stimulus-driven cocaine-seeking following withdrawal. Importantly, L-AP4 had no effect on lever pressing for sucrose pellets or general motoric behavior. Finally, using whole-cell patch-clamp recordings from identified orexin cells in orexin-GFP transgenic mice, we show enhanced presynaptic drive to orexin cells following 14d withdrawal and that this plasticity can be normalized by L-AP4. Together, these data indicate that activation of group III mGluRs in LHA reduces orexin cell activity in vivo and may be an effective strategy to suppress cocaine-seeking behavior following withdrawal. These effects are likely mediated, at least in part, by normalization of presynaptic plasticity at orexin cells that occurs as a result of cocaine exposure. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Tyree SM, Borniger JC, de Lecea L. Hypocretin as a Hub for Arousal and Motivation. Front Neurol 2018; 9:413. [PMID: 29928253 PMCID: PMC5997825 DOI: 10.3389/fneur.2018.00413] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/18/2018] [Indexed: 01/01/2023] Open
Abstract
The lateral hypothalamus is comprised of a heterogeneous mix of neurons that serve to integrate and regulate sleep, feeding, stress, energy balance, reward, and motivated behavior. Within these populations, the hypocretin/orexin neurons are among the most well studied. Here, we provide an overview on how these neurons act as a central hub integrating sensory and physiological information to tune arousal and motivated behavior accordingly. We give special attention to their role in sleep-wake states and conditions of hyper-arousal, as is the case with stress-induced anxiety. We further discuss their roles in feeding, drug-seeking, and sexual behavior, which are all dependent on the motivational state of the animal. We further emphasize the application of powerful techniques, such as optogenetics, chemogenetics, and fiber photometry, to delineate the role these neurons play in lateral hypothalamic functions.
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Affiliation(s)
- Susan M Tyree
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
| | - Jeremy C Borniger
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
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Ferraro S, Nigri A, Bruzzone MG, Brivio L, Proietti Cecchini A, Verri M, Chiapparini L, Leone M. Defective functional connectivity between posterior hypothalamus and regions of the diencephalic-mesencephalic junction in chronic cluster headache. Cephalalgia 2018. [PMID: 29517304 DOI: 10.1177/0333102418761048] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We tested the hypothesis of a defective functional connectivity between the posterior hypothalamus and diencephalic-mesencephalic regions in chronic cluster headache based on: a) clinical and neuro-endocrinological findings in cluster headache patients; b) neuroimaging findings during cluster headache attacks; c) neuroimaging findings in drug-refractory chronic cluster headache patients improved after successful deep brain stimulation. METHODS Resting state functional magnetic resonance imaging, associated with a seed-based approach, was employed to investigate the functional connectivity of the posterior hypothalamus in chronic cluster headache patients (n = 17) compared to age and sex-matched healthy subjects (n = 16). Random-effect analyses were performed to study differences between patients and controls in ipsilateral and contralateral-to-the-pain posterior hypothalamus functional connectivity. RESULTS Cluster headache patients showed an increased functional connectivity between the ipsilateral posterior hypothalamus and a number of diencephalic-mesencephalic structures, comprising ventral tegmental area, dorsal nuclei of raphe, and bilateral substantia nigra, sub-thalamic nucleus, and red nucleus ( p < 0.005 FDR-corrected vs . control group). No difference between patients and controls was found comparing the contralateral hypothalami. CONCLUSIONS The observed deranged functional connectivity between the posterior ipsilateral hypothalamus and diencephalic-mesencephalic regions in chronic cluster headache patients mainly involves structures that are part of (i.e. ventral tegmental area, substantia nigra) or modulate (dorsal nuclei of raphe, sub-thalamic nucleus) the midbrain dopaminergic systems. The midbrain dopaminergic systems could play a role in cluster headache pathophysiology and in particular in the chronicization process. Future studies are needed to better clarify if this finding is specific to cluster headache or if it represents an unspecific response to chronic pain.
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Affiliation(s)
- Stefania Ferraro
- 1 Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Anna Nigri
- 1 Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Maria Grazia Bruzzone
- 1 Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Luca Brivio
- 1 Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Alberto Proietti Cecchini
- 2 Headache and Neuroalgology Department, Pain Neuromodulation Unit of Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Mattia Verri
- 1 Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Luisa Chiapparini
- 1 Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Massimo Leone
- 2 Headache and Neuroalgology Department, Pain Neuromodulation Unit of Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
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Messina A, Bitetti I, Precenzano F, Iacono D, Messina G, Roccella M, Parisi L, Salerno M, Valenzano A, Maltese A, Salerno M, Sessa F, Albano GD, Marotta R, Villano I, Marsala G, Zammit C, Lavano F, Monda M, Cibelli G, Lavano SM, Gallai B, Toraldo R, Monda V, Carotenuto M. Non-Rapid Eye Movement Sleep Parasomnias and Migraine: A Role of Orexinergic Projections. Front Neurol 2018. [PMID: 29541053 PMCID: PMC5835506 DOI: 10.3389/fneur.2018.00095] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Introduction Sleep and migraine share a common pathophysiological substrate, although the underlying mechanisms are unknown. The serotonergic and orexinergic systems are both involved in the regulation of sleep/wake cycle, and numerous studies show that both are involved in the migraine etiopathogenesis. These two systems are anatomically and functionally interconnected. Our hypothesis is that in migraine a dysfunction of orexinergic projections on the median raphe (MR) nuclei, interfering with serotonergic regulation, may cause Non-Rapid Eye Movement parasomnias, such as somnambulism. Hypothesis/theory Acting on the serotonergic neurons of the raphe nuclei, the dysfunction of orexinergic neurons would lead to a higher release of serotonin. The activation of serotonergic receptors located on the walls of large cerebral vessels would lead to abnormal vasodilatation and consequently increase transmural pressure. This process could activate the trigeminal nerve terminals that innervate vascular walls. As a consequence, there is activation of sensory nerve endings at the level of hard vessels in the meninges, with release of pro-inflammatory peptides (e.g., substance P and CGRP). Within this hypothetical frame, the released serotonin could also interact with trigeminovascular afferents to activate and/or facilitate the release of the neuropeptide at the level of the trigeminal ganglion. The dysregulation of the physiological negative feedback of serotonin on the orexinergic neurons, in turn, would contribute to an alteration of the whole system, altering the sleep–wake cycle. Conclusion Serotonergic neurons of the MR nuclei receive an excitatory input from hypothalamic orexin/hypocretin neurons and reciprocally inhibit orexin/hypocretin neurons through the serotonin 1A receptor (or 5-HT1A receptor). Considering this complex system, if there is an alteration it may facilitate the pathophysiological mechanisms involved in the migraine, while it may produce at the same time an alteration of the sleep–wake rhythm, causing sleep disorders such as sleepwalking. Understanding the complex mechanisms underlying migraine and sleep disorders and how these mechanisms can interact with each other, it would be crucial to pave the way for new therapeutic strategies.
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Affiliation(s)
- Antonietta Messina
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Ilaria Bitetti
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Francesco Precenzano
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Diego Iacono
- Neurodevelopmental Research Lab, Biomedical Research Institute of New Jersey (BRInj), Cedar Knolls NJ, United States.,Neuroscience Research, MidAtlantic Neonatology Associates, Atlantic Health System, Morristown NJ, United States.,Neuropathology Research, MidAtlantic Neonatology Associates (MANA) and Biomedical Research Institute of New Jersey (BRInj), Morristown, NJ, United States
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Michele Roccella
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Lucia Parisi
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Margherita Salerno
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Agata Maltese
- Child Neuropsychiatry, Department of Psychology and Pedagogical Sciences, University of Palermo, Palermo, Italy
| | - Monica Salerno
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Francesco Sessa
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | | | - Rosa Marotta
- Department of Health Sciences, University "Magna Graecia", Catanzaro, Italy
| | - Ines Villano
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Gabriella Marsala
- Struttura Complessa di Farmacia, Azienda Ospedaliero-Universitaria, Ospedali Riuniti di Foggia, Foggia, Italy
| | - Christian Zammit
- Anatomy Department, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Francesco Lavano
- Department of Health Sciences, University "Magna Graecia", Catanzaro, Italy
| | - Marcellino Monda
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | | | - Beatrice Gallai
- Department of Surgical and Biomedical Sciences, University of Perugia, Perugia, Italy
| | - Roberto Toraldo
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Vincenzo Monda
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Marco Carotenuto
- Clinic of Child and Adolescent Neuropsychiatry, Center for Childhood Headache, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
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Restoring Serotonergic Homeostasis in the Lateral Hypothalamus Rescues Sleep Disturbances Induced by Early-Life Obesity. J Neurosci 2017; 38:441-451. [PMID: 29196316 DOI: 10.1523/jneurosci.1333-17.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/13/2017] [Accepted: 10/12/2017] [Indexed: 01/09/2023] Open
Abstract
Early-life obesity predisposes to obesity in adulthood, a condition with broad medical implications including sleep disorders, which can exacerbate metabolic disturbances and disrupt cognitive and affective behaviors. In this study, we examined the long-term impact of transient peripubertal diet-induced obesity (ppDIO, induced between 4 and 10 weeks of age) on sleep-wake behavior in male mice. EEG and EMG recordings revealed that ppDIO increases sleep during the active phase but reduces resting-phase sleep quality. This impaired sleep phenotype persisted for up to 1 year, although animals were returned to a non-obesiogenic diet from postnatal week 11 onwards. To better understand the mechanisms responsible for the ppDIO-induced alterations in sleep, we focused on the lateral hypothalamus (LH). Mice exposed to ppDIO did not show altered mRNA expression levels of orexin and melanin-concentrating hormone, two peptides that are important for sleep-wake behavior and food intake. Conversely, the LH of ppDIO-exposed mice had reduced contents of serotonin (5-hydroxytryptamine, 5-HT), a neurotransmitter involved in both sleep-wake and satiety regulation. Interestingly, an acute peripheral injection of the satiety-signaling peptide YY 3-36 increased 5-HT turnover in the LH and ameliorated the ppDIO-induced sleep disturbances, suggesting the therapeutic potential of this peptide. These findings provide new insights into how sleep-wake behavior is programmed during early life and how peripheral and central signals are integrated to coordinate sleep.SIGNIFICANCE STATEMENT Adult physiology and behavior are strongly influenced by dynamic reorganization of the brain during puberty. The present work shows that obesity during puberty leads to persistently dysregulated patterns of sleep and wakefulness by blunting serotonergic signaling in the lateral hypothalamus. It also shows that pharmacological mimicry of satiety with peptide YY3-36 can reverse this neurochemical imbalance and acutely restore sleep composition. These findings add insight into how innate behaviors such as feeding and sleep are integrated and suggest a novel mechanism through which diet-induced obesity during puberty imposes its long-lasting effects on sleep-wake behavior.
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Role of orexin-2 receptors in the nucleus accumbens in antinociception induced by carbachol stimulation of the lateral hypothalamus in formalin test. Behav Pharmacol 2017; 27:431-8. [PMID: 26871404 DOI: 10.1097/fbp.0000000000000216] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Orexins, which are mainly produced by orexin-expressing neurons in the lateral hypothalamus (LH), play an important role in pain modulation. Previously, it has been established that the nucleus accumbens (NAc) is involved in the modulation of formalin-induced nociceptive responses, a model of tonic pain. In this study, the role of intra-accumbal orexin-2 receptors (OX2rs) in the mediation of formalin-induced pain was investigated. A volume of 0.5 μl of 10, 20, and 40 nmol/l solutions of TCS OX2 29, an OX2r antagonist, were unilaterally microinjected into the NAc 5 min before an intra-LH carbachol microinjection (0.5 μl of 250 nmol/l solution). After 5 min, animals received a subcutaneous injection of formalin 2.5% (50 μl) into the hind paw. Pain-related behaviors were assessed at 5 min intervals during a 60-min test period. The findings showed that TCS OX2 29 administration dose dependently blocked carbachol-induced antinociception during both phases of formalin-induced pain. The antianalgesic effect of TCS OX2 29 was greater during the late phase compared with the early phase. These observations suggest that the NAc, as a part of a descending pain-modulatory circuitry, partially mediates LH-induced analgesia in the formalin test through recruitment of OX2rs. This makes the orexinergic system a good potential therapeutic target in the control of persistent inflammatory pain.
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Mapping the Hypocretin/Orexin Neuronal System: An Unexpectedly Productive Journey. J Neurosci 2017; 37:2268-2272. [PMID: 28250055 DOI: 10.1523/jneurosci.1708-16.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 10/25/2016] [Indexed: 11/21/2022] Open
Abstract
Early in 1998, we (de Lecea et al., 1998) and others (Sakurai et al., 1998) described the same hypothalamic neuropeptides, respectively called the hypocretins or orexins, which were discovered using two different approaches. In December of that year, we published the subject of this commentary in the Journal of Neuroscience: a highly detailed anatomical description of the extensive axonal projections of the hypocretin/orexin neurons. Although the function of this system was unknown at the time, a large body of literature today attests that the hypocretin/orexin neuropeptides play important roles in multiple physiological functions, particularly in sleep/wake regulation. Neuroanatomical studies are rarely frontline news, but the citation rate of this paper underscores the critical nature of such basic research. Based in part on this detailed description, the hypocretin/orexin neuropeptides have since been studied in many different areas of neuroscience research, including sleep/wake regulation, feeding, addiction, reward and motivation, anxiety and depression, cardiovascular regulation, pain, migraine, and neuroendocrine regulation, including reproduction. Thus, this paper has had a surprisingly broad impact on neuroscience research, particularly since it was originally rejected by the Journal!
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44
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Ogawa Y, Kanda T, Vogt K, Yanagisawa M. Anatomical and electrophysiological development of the hypothalamic orexin neurons from embryos to neonates. J Comp Neurol 2017; 525:3809-3820. [PMID: 28608460 DOI: 10.1002/cne.24261] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 04/19/2017] [Accepted: 04/19/2017] [Indexed: 02/01/2023]
Abstract
The amount, quality, and diurnal pattern of sleep change greatly during development. Developmental changes of sleep/wake architecture are in a close relationship to brain development. The fragmentation of wake episodes is one of the salient features in the neonatal period, which is also observed in mature animals and human individuals lacking neuropeptide orexin/hypocretin signaling. This raises the possibility that developmental changes of lateral hypothalamic orexin neurons are relevant to the development of sleep/wake architecture. However, little information is available on morphological and physiological features of developing orexin neurons. To address the cellular basis for maturation of the sleep/wake regulatory system, we investigated the functional development of orexin neurons in the lateral hypothalamus. The anatomical development as well as the changes in the electrophysiological characteristics of orexin neurons was examined from embryonic to postnatal stages in orexin-EGFP mice. Prepro-orexin promoter activity was detectable at embryonic day (E) 12.0, followed by expression of orexin A after E14.0. The number of orexin neurons and their membrane capacitance reached similar levels to adults by postnatal day (P) 7, while their membrane potentials, firing rates, and action potential waveforms were developed by P21. The hyperpolarizing effect of serotonin, which is a major inhibitory signal for adult orexin neurons, was detected after E18.0 and matured at P1. These results suggest that the expression of orexin peptides precedes the maturation of electrophysiological activity of orexin neurons. The function of orexin neurons gradually matures by 3 weeks after birth, coinciding with maturation of sleep/wake architecture.
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Affiliation(s)
- Yukino Ogawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takeshi Kanda
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kaspar Vogt
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan.,Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas
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Chieffi S, Carotenuto M, Monda V, Valenzano A, Villano I, Precenzano F, Tafuri D, Salerno M, Filippi N, Nuccio F, Ruberto M, De Luca V, Cipolloni L, Cibelli G, Mollica MP, Iacono D, Nigro E, Monda M, Messina G, Messina A. Orexin System: The Key for a Healthy Life. Front Physiol 2017; 8:357. [PMID: 28620314 PMCID: PMC5450021 DOI: 10.3389/fphys.2017.00357] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/15/2017] [Indexed: 11/30/2022] Open
Abstract
The orexin-A/hypocretin-1 and orexin-B/hypocretin-2 are neuropeptides synthesized by a cluster of neurons in the lateral hypothalamus and perifornical area. Orexin neurons receive a variety of signals related to environmental, physiological and emotional stimuli, and project broadly to the entire CNS. Orexin neurons are “multi-tasking” neurons regulating a set of vital body functions, including sleep/wake states, feeding behavior, energy homeostasis, reward systems, cognition and mood. Furthermore, a dysfunction of orexinergic system may underlie different pathological conditions. A selective loss orexin neurons was found in narcolepsia, supporting the crucial role of orexins in maintaining wakefulness. In animal models, orexin deficiency lead to obesity even if the consume of calories is lower than wildtype counterpart. Reduced physical activity appears the main cause of weight gain in these models resulting in energy imbalance. Orexin signaling promotes obesity resistance via enhanced spontaneous physical activity and energy expenditure regulation and the deficiency/dysfunction in orexins system lead to obesity in animal models despite of lower calories intake than wildtype associated with reduced physical activity. Interestingly, orexinergic neurons show connections to regions involved in cognition and mood regulation, including hippocampus. Orexins enhance hippocampal neurogenesis and improve spatial learning and memory abilities, and mood. Conversely, orexin deficiency results in learning and memory deficits, and depression.
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Affiliation(s)
- Sergio Chieffi
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Marco Carotenuto
- Department of Mental Health, Physical and Preventive Medicine, Clinic of Child and Adolescent Neuropsychiatry, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Vincenzo Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of FoggiaFoggia, Italy
| | - Ines Villano
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Francesco Precenzano
- Department of Mental Health, Physical and Preventive Medicine, Clinic of Child and Adolescent Neuropsychiatry, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Domenico Tafuri
- Department of Motor Sciences and Wellness, University of Naples "Parthenope"Naples, Italy
| | - Monica Salerno
- Department of Mental Health, Physical and Preventive Medicine, Clinic of Child and Adolescent Neuropsychiatry, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Nicola Filippi
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Francesco Nuccio
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Maria Ruberto
- Department of Medical-Surgical and Dental Specialties, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Vincenzo De Luca
- Department of Psychiatry, University of TorontoToronto, ON, Canada
| | - Luigi Cipolloni
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Università degli Studi di Roma La SapienzaRome, Italy
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of FoggiaFoggia, Italy
| | - Maria P Mollica
- Department of Biology Università degli Studi di Napoli Federico IINaples, Italy
| | - Diego Iacono
- Neurodevelopmental Research Lab, Biomedical Research Institute of New JerseyMorristown, NJ, United States.,Neuroscience Research, MidAtlantic Neonatology Associates, Atlantic Health SystemMorristown, NJ, United States.,Neuropathology Research, MANA/Biomedical Research Institute of New JerseyMorristown, NJ, United States
| | | | - Marcellino Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
| | - Giovanni Messina
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy.,Department of Clinical and Experimental Medicine, University of FoggiaFoggia, Italy
| | - Antonietta Messina
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Università degli Studi della Campania "Luigi Vanvitelli"Naples, Italy
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Ono D, Yamanaka A. Hypothalamic regulation of the sleep/wake cycle. Neurosci Res 2017; 118:74-81. [PMID: 28526553 DOI: 10.1016/j.neures.2017.03.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/02/2017] [Accepted: 03/13/2017] [Indexed: 12/30/2022]
Abstract
Sleep is one of the most important physiological functions in mammals. It is regulated by not only homeostatic regulation but also circadian clock. Several neuropeptide-producing neurons located in the hypothalamus are implicated in the regulation of sleep/wakefulness. Among them, orexin/hypocretin-producing neurons (orexin neurons) are a crucial component for maintenance of wakefulness, because lack of orexin function results in narcolepsy, which is a sleep disorder. Recent findings have identified substances that excite or inhibit neural activity of orexin neurons. Furthermore neural projections of the neurons which release these substances have been revealed. In addition to orexin, melanin concentrating hormone (MCH)-producing neurons in the lateral hypothalamic area (LHA) are also implicated in the regulation of sleep/wakefulness. MCH neurons are active during sleep but become silent during wakefulness. Recently developed innovative methods including optogenetics and pharmacogenetics have provided substantial insights into the regulation of sleep/wakefulness. In vivo optical recordings and retrograde and anterograde tracing methods will allow us to understand additional details regarding important interactions between these two types of neurons in the LHA and other neurons in the brain. Finally we discuss the circadian clock and sleep/wake cycle. Understanding of the neural networks and its circadian modulation of sleep/wake cycles remain to be investigated.
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Affiliation(s)
- Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
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Agostinelli LJ, Ferrari LL, Mahoney CE, Mochizuki T, Lowell BB, Arrigoni E, Scammell TE. Descending projections from the basal forebrain to the orexin neurons in mice. J Comp Neurol 2017; 525:1668-1684. [PMID: 27997037 PMCID: PMC5806522 DOI: 10.1002/cne.24158] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/02/2016] [Accepted: 11/02/2016] [Indexed: 12/23/2022]
Abstract
The orexin (hypocretin) neurons play an essential role in promoting arousal, and loss of the orexin neurons results in narcolepsy, a condition characterized by chronic sleepiness and cataplexy. The orexin neurons excite wake-promoting neurons in the basal forebrain (BF), and a reciprocal projection from the BF back to the orexin neurons may help promote arousal and motivation. The BF contains at least three different cell types (cholinergic, glutamatergic, and γ-aminobutyric acid (GABA)ergic neurons) across its different regions (medial septum, diagonal band, magnocellular preoptic area, and substantia innominata). Given the neurochemical and anatomical heterogeneity of the BF, we mapped the pattern of BF projections to the orexin neurons across multiple BF regions and neuronal types. We performed conditional anterograde tracing using mice that express Cre recombinase only in neurons producing acetylcholine, glutamate, or GABA. We found that the orexin neurons are heavily apposed by axon terminals of glutamatergic and GABAergic neurons of the substantia innominata (SI) and magnocellular preoptic area, but there was no innervation by the cholinergic neurons. Channelrhodopsin-assisted circuit mapping (CRACM) demonstrated that glutamatergic SI neurons frequently form functional synapses with the orexin neurons, but, surprisingly, functional synapses from SI GABAergic neurons were rare. Considering their strong reciprocal connections, BF and orexin neurons likely work in concert to promote arousal, motivation, and other behaviors. J. Comp. Neurol. 525:1668-1684, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Lindsay J Agostinelli
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Loris L Ferrari
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Carrie E Mahoney
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Takatoshi Mochizuki
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Bradford B Lowell
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
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48
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Mieda M. The roles of orexins in sleep/wake regulation. Neurosci Res 2017; 118:56-65. [DOI: 10.1016/j.neures.2017.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 10/25/2022]
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49
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Kooshki R, Abbasnejad M, Esmaeili-Mahani S, Raoof M. The Modulatory Role of Orexin 1 Receptor in CA1 on Orofacial Pain-induced Learning and Memory Deficits in Rats. Basic Clin Neurosci 2017; 8:213-222. [PMID: 28781729 PMCID: PMC5535327 DOI: 10.18869/nirp.bcn.8.3.213] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Introduction: Cognitive impairment is commonly associated with pain. The modulatory role of orexin 1 receptor (OX1R) in pain pathways as well as learning and memory processes is reported in several studies. The current study was designed to investigate the possible role of CA1-hippocampal OX1R on spatial learning and memory of rats following capsaicin-induced orofacial pain. Methods: Orofacial pain was induced by subcutaneous intra lip injection of capsaicin (100 μg). CA1 administration of orexin A and its selective antagonist (SB-334867-A) were performed 20 minutes prior to capsaicin injection. Learning and spatial memory performances were assessed by Morris Water Maze (MWM) task. Results: Capsaicin treated rats showed impairment in spatial learning and memory. In addition, pretreatment with orexin A (20 and 40 nM/rat) significantly attenuated learning and memory impairment in capsaicin-treated rats. Conversely, blockage of OX1R via SB-334867-A (40 and 80 nM/rat) significantly exaggerated learning and memory loss in capsaicin-treated rats. Conclusion: The obtained results indicated that CA1 OX1R may be involved in modulation of capsaicin –induced spatial learning and memory impairment.
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Affiliation(s)
- Razieh Kooshki
- Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Mehdi Abbasnejad
- Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Saeed Esmaeili-Mahani
- Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Maryam Raoof
- Laboratory of Molecular Neuroscience, Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.,Department of Endodontics, School of Dentistry, Kerman University of Medical Sciences, Kerman, Iran
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Yamashita T, Yamanaka A. Lateral hypothalamic circuits for sleep-wake control. Curr Opin Neurobiol 2017; 44:94-100. [PMID: 28427008 DOI: 10.1016/j.conb.2017.03.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/31/2017] [Indexed: 12/12/2022]
Abstract
The lateral hypothalamic area (LHA) of the diencephalon is crucially involved in controlling instinctive behavior such as sleep-wake cycle and feeding behavior. LHA is a heterogeneous structure that contains spatially intermingled, genetically distinct cell populations. Among LHA neurons, orexin/hypocretin (OX) neuron is the key cell type that promotes waking, and specific loss of OX neurons results in narcolepsy. Melanin-concentrating hormone (MCH) containing neurons are known to be active during rapid eye movement (REM) sleep and stimulation of these neurons promotes REM sleep. Here we review the classical and more recent findings in this field and discuss the molecular and cellular network organization of LHA neurons that could ultimately regulate the switch between wakefulness and general states of sleep.
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Affiliation(s)
- Takayuki Yamashita
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan; CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan; CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
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