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Fiala A, Kaun KR. What do the mushroom bodies do for the insect brain? Twenty-five years of progress. Learn Mem 2024; 31:a053827. [PMID: 38862175 PMCID: PMC11199942 DOI: 10.1101/lm.053827.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Accepted: 04/22/2024] [Indexed: 06/13/2024]
Abstract
In 1998, a special edition of Learning & Memory was published with a discrete focus of synthesizing the state of the field to provide an overview of the function of the insect mushroom body. While molecular neuroscience and optical imaging of larger brain areas were advancing, understanding the basic functioning of neuronal circuits, particularly in the context of the mushroom body, was rudimentary. In the past 25 years, technological innovations have allowed researchers to map and understand the in vivo function of the neuronal circuits of the mushroom body system, making it an ideal model for investigating the circuit basis of sensory encoding, memory formation, and behavioral decisions. Collaborative efforts within the community have played a crucial role, leading to an interactive connectome of the mushroom body and accessible genetic tools for studying mushroom body circuit function. Looking ahead, continued technological innovation and collaborative efforts are likely to further advance our understanding of the mushroom body and its role in behavior and cognition, providing insights that generalize to other brain structures and species.
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Affiliation(s)
- André Fiala
- Department of Molecular Neurobiology of Behaviour, University of Göttingen, Göttingen 37077, Germany
| | - Karla R Kaun
- Department of Neuroscience, Brown University, Providence, Rhode Island 02806, USA
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2
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Caprioli B, Eichler RAS, Silva RNO, Martucci LF, Reckziegel P, Ferro ES. Neurolysin Knockout Mice in a Diet-Induced Obesity Model. Int J Mol Sci 2023; 24:15190. [PMID: 37894869 PMCID: PMC10607720 DOI: 10.3390/ijms242015190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
Neurolysin oligopeptidase (E.C.3.4.24.16; Nln), a member of the zinc metallopeptidase M3 family, was first identified in rat brain synaptic membranes hydrolyzing neurotensin at the Pro-Tyr peptide bond. The previous development of C57BL6/N mice with suppression of Nln gene expression (Nln-/-), demonstrated the biological relevance of this oligopeptidase for insulin signaling and glucose uptake. Here, several metabolic parameters were investigated in Nln-/- and wild-type C57BL6/N animals (WT; n = 5-8), male and female, fed either a standard (SD) or a hypercaloric diet (HD), for seven weeks. Higher food intake and body mass gain was observed for Nln-/- animals fed HD, compared to both male and female WT control animals fed HD. Leptin gene expression was higher in Nln-/- male and female animals fed HD, compared to WT controls. Both WT and Nln-/- females fed HD showed similar gene expression increase of dipeptidyl peptidase 4 (DPP4), a peptidase related to glucagon-like peptide-1 (GLP-1) metabolism. The present data suggest that Nln participates in the physiological mechanisms related to diet-induced obesity. Further studies will be necessary to better understand the molecular mechanism responsible for the higher body mass gain observed in Nln-/- animals fed HD.
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Affiliation(s)
- Bruna Caprioli
- Pharmacology Department, Biomedical Sciences Institute (ICB), São Paulo 05508-000, SP, Brazil; (B.C.); (R.A.S.E.); (R.N.O.S.); (L.F.M.)
| | - Rosangela A. S. Eichler
- Pharmacology Department, Biomedical Sciences Institute (ICB), São Paulo 05508-000, SP, Brazil; (B.C.); (R.A.S.E.); (R.N.O.S.); (L.F.M.)
| | - Renée N. O. Silva
- Pharmacology Department, Biomedical Sciences Institute (ICB), São Paulo 05508-000, SP, Brazil; (B.C.); (R.A.S.E.); (R.N.O.S.); (L.F.M.)
| | - Luiz Felipe Martucci
- Pharmacology Department, Biomedical Sciences Institute (ICB), São Paulo 05508-000, SP, Brazil; (B.C.); (R.A.S.E.); (R.N.O.S.); (L.F.M.)
| | - Patricia Reckziegel
- Department of Clinical and Toxicological Analysis, Faculty of Pharmaceutical Sciences (FCF), University of São Paulo (USP), São Paulo 05508-000, SP, Brazil;
| | - Emer S. Ferro
- Pharmacology Department, Biomedical Sciences Institute (ICB), São Paulo 05508-000, SP, Brazil; (B.C.); (R.A.S.E.); (R.N.O.S.); (L.F.M.)
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3
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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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4
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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: 0] [Impact Index Per Article: 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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5
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Osada K, Kujirai R, Hosono A, Tsuda M, Ohata M, Ohta T, Nishimori K. Repeated exposure to kairomone-containing coffee odor improves abnormal olfactory behaviors in heterozygous oxytocin receptor knock-in mice. Front Behav Neurosci 2023; 16:983421. [PMID: 36817409 PMCID: PMC9930907 DOI: 10.3389/fnbeh.2022.983421] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 12/16/2022] [Indexed: 02/04/2023] Open
Abstract
The oxytocin receptor (OXTR) knockout mouse is a model of autism spectrum disorder, characterized by abnormalities in social and olfactory behaviors and learning. Previously, we demonstrated that OXTR plays a crucial role in regulating aversive olfactory behavior to butyric acid odor. In this study, we attempted to determine whether coffee aroma affects the abnormal olfactory behavior of OXTR-Venus knock-in heterozygous mice [heterozygous OXTR (±) mice] using a set of behavioral and molecular experiments. Four-week repeated exposures of heterozygous OXTR (±) mice to coffee odor, containing three kairomone alkylpyrazines, rescued the abnormal olfactory behaviors compared with non-exposed wild-type or heterozygous OXTR (±) mice. Increased Oxtr mRNA expression in the olfactory bulb and amygdala coincided with the rescue of abnormal olfactory behaviors. In addition, despite containing the kairomone compounds, both the wild-type and heterozygous OXTR (±) mice exhibited a preference for the coffee odor and exhibited no stress-like increase in the corticotropin-releasing hormone, instead of a kairomone-associated avoidance response. The repeated exposures to the coffee odor did not change oxytocin and estrogen synthetase/receptors as a regulator of the gonadotropic hormone. These data suggest that the rescue of abnormal olfactory behaviors in heterozygous OXTR (±) mice is due to the coffee odor exposure-induced OXTR expression.
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Affiliation(s)
- Kazumi Osada
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University, Fujisawa, Japan,*Correspondence: Kazumi Osada,
| | - Riyuki Kujirai
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Akira Hosono
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Masato Tsuda
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Motoko Ohata
- Department of Food Bioscience and Biotechnology, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Tohru Ohta
- The Research Institute of Health Science, Health Sciences University of Hokkaido, Tobetsu, Japan
| | - Katsuhiko Nishimori
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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6
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Li Y, Cui ZJ. Photodynamic Activation of the Cholecystokinin 1 Receptor with Tagged Genetically Encoded Protein Photosensitizers: Optimizing the Tagging Patterns. Photochem Photobiol 2022; 98:1215-1228. [PMID: 35211987 DOI: 10.1111/php.13611] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 02/20/2022] [Indexed: 02/05/2023]
Abstract
Cholecystokinin 1 receptor (CCK1R) is activated photodynamically. For this to happen in situ, genetically encoded protein photosensitizers (GEPP) may be tagged to natively expressed CCK1R, but how to best tag GEPP has not been examined. Therefore, GEPP (miniSOG or KillerRed) was tagged to CCK1R and light-driven photodynamic CCK1R activation was monitored by Fura-2 fluorescent calcium imaging, to screen for optimized tagging patterns. Blue light-emitting diode irradiation of CHO-K1 cells expressing miniSOG fused to N- or C-terminus of CCK1R was found to both trigger persistent calcium oscillations-a hallmark of permanent photodynamic CCK1R activation. Photodynamic CCK1R activation was accomplished also with miniSOG fused to N-terminus of CCK1R via linker (GlySerGly)4 or 8 , but not linker (GSG)12 or an internal ribosomal entry site insert. KillerRed fused to N- or C-terminus of CCK1R after white light irradiation resulted in similar activation of in-frame CCK1R. Photodynamic CCK1R activation in miniSOG-CCK1R-CHO-K1 cells was blocked by singlet oxygen (1 O2 ) quencher uric acid or Trolox C, corroborating the role of 1 O2 as the reactive intermediate. It is concluded that photodynamic CCK1R activation can be achieved either with direct GEPP fusion to CCK1R or fusion via a short linker, fusion via long linkers might serve as the internal control.
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Affiliation(s)
- Yuan Li
- Institute of Cell Biology, Beijing Normal University, Beijing, China
| | - Zong Jie Cui
- Institute of Cell Biology, Beijing Normal University, Beijing, China
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7
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Valencia FP, Marino AF, Noutsos C, Poon K. Concentration-dependent change in hypothalamic neuronal transcriptome by the dietary fatty acids: oleic and palmitic acids. J Nutr Biochem 2022; 106:109033. [DOI: 10.1016/j.jnutbio.2022.109033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 12/20/2021] [Accepted: 03/18/2022] [Indexed: 11/30/2022]
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8
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Kim YR, Lee SY, Lee SM, Shim I, Lee MY. Effect of Hibiscus syriacus Linnaeus extract and its active constituent, saponarin, in animal models of stress-induced sleep disturbances and pentobarbital-induced sleep. Biomed Pharmacother 2022; 146:112301. [PMID: 34915415 DOI: 10.1016/j.biopha.2021.112301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 12/31/2022] Open
Abstract
Treatment of sleep disorders promotes the long-term use of commercially available sleep inducers that have several adverse effects, including addiction, systemic fatigue, weakness, loss of concentration, headache, and digestive problems. Therefore, we aimed to limit these adverse effects by investigating a natural product, the extract of the Hibiscus syriacus Linnaeus flower (HSF), as an alternative treatment. In the electric footshock model, we measured anxiety and assessed the degree of sleep improvement after administering HSF extract. In the restraint model, we studied the sleep rate using PiezoSleep, a noninvasive assessment system. In the pentobarbital model, we measured sleep improvement and changes in sleep-related factors. Our first model confirmed the desirable effects of HSF extract and its active constituent, saponarin, on anxiolysis and Wake times. HSF extract also increased REM sleep time. Furthermore, HSF extract and saponarin increased the expression of cortical GABAA receptor α1 (GABAAR α1) and c-Fos in the ventrolateral preoptic nucleus (VLPO). In the second model, HSF extract and saponarin restored the sleep rate and the sleep bout duration. In the third model, HSF extract and saponarin increased sleep maintenance time. Moreover, HSF extract and saponarin increased cortical cholecystokinin (CCK) mRNA levels and the expression of VLPO c-Fos. HSF extract also increased GABAAR α1 mRNA level. Our results suggest that HSF extract and saponarin are effective in maintaining sleep and may be used as a novel treatment for sleep disorder. Eventually, we hope to introduce HSF and saponarin as a clinical treatment for sleep disorders in humans.
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MESH Headings
- Animals
- Apigenin/pharmacology
- Apigenin/therapeutic use
- Cerebral Cortex/drug effects
- Cerebral Cortex/metabolism
- Cerebral Cortex/physiology
- Corticosterone/blood
- Disease Models, Animal
- Electroencephalography
- Glucosides/pharmacology
- Glucosides/therapeutic use
- Hibiscus
- Male
- Mice, Inbred C57BL
- Mice, Inbred ICR
- Pentobarbital
- Plant Extracts/pharmacology
- Plant Extracts/therapeutic use
- Preoptic Area/drug effects
- Preoptic Area/metabolism
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-fos/metabolism
- Rats, Sprague-Dawley
- Receptors, GABA-A/genetics
- Sleep/drug effects
- Sleep Aids, Pharmaceutical
- Sleep Wake Disorders/blood
- Sleep Wake Disorders/drug therapy
- Sleep Wake Disorders/genetics
- Sleep Wake Disorders/physiopathology
- Stress, Psychological/blood
- Stress, Psychological/complications
- Stress, Psychological/genetics
- Stress, Psychological/physiopathology
- Mice
- Rats
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Affiliation(s)
- Yu Ri Kim
- KM Convergence Research Division, Korea Institute of Oriental Medicine, 1672, Yuseong-daero, Yuseong-gu, Daejeon 34054, Republic of Korea.
| | - Sun Young Lee
- Department of Physiology, School of Medicine, Kyung Hee University, 26, Gyeonghui-daero, Dongdaemun-gu, Seoul 02447, Republic of Korea.
| | - So Min Lee
- KM Convergence Research Division, Korea Institute of Oriental Medicine, 1672, Yuseong-daero, Yuseong-gu, Daejeon 34054, Republic of Korea.
| | - Insop Shim
- Department of Physiology, School of Medicine, Kyung Hee University, 26, Gyeonghui-daero, Dongdaemun-gu, Seoul 02447, Republic of Korea.
| | - Mi Young Lee
- KM Convergence Research Division, Korea Institute of Oriental Medicine, 1672, Yuseong-daero, Yuseong-gu, Daejeon 34054, Republic of Korea.
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Vaseghi S, Zarrabian S, Haghparast A. Reviewing the role of the orexinergic system and stressors in modulating mood and reward-related behaviors. Neurosci Biobehav Rev 2021; 133:104516. [PMID: 34973302 DOI: 10.1016/j.neubiorev.2021.104516] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 01/22/2023]
Abstract
In this review study, we aimed to introduce the orexinergic system as an important signaling pathway involved in a variety of cognitive functions such as memory, motivation, and reward-related behaviors. This study focused on the role of orexinergic system in modulating reward-related behavior, with or without the presence of stressors. Cross-talk between the reward system and orexinergic signaling was also investigated, especially orexinergic signaling in the ventral tegmental area (VTA), the nucleus accumbens (NAc), and the hippocampus. Furthermore, we discussed the role of the orexinergic system in modulating mood states and mental illnesses such as depression, anxiety, panic, and posttraumatic stress disorder (PTSD). Here, we narrowed down our focus on the orexinergic signaling in three brain regions: the VTA, NAc, and the hippocampus (CA1 region and dentate gyrus) for their prominent role in reward-related behaviors and memory. It was concluded that the orexinergic system is critically involved in reward-related behavior and significantly alters stress responses and stress-related psychiatric and mood disorders.
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Affiliation(s)
- Salar Vaseghi
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran
| | - Shahram Zarrabian
- Department of Anatomical Sciences & Cognitive Neuroscience, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.
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10
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Raymond JS, Rehn S, Hoyos CM, Bowen MT. The influence of oxytocin-based interventions on sleep-wake and sleep-related behaviour and neurobiology: A systematic review of preclinical and clinical studies. Neurosci Biobehav Rev 2021; 131:1005-1026. [PMID: 34673110 DOI: 10.1016/j.neubiorev.2021.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 12/26/2022]
Abstract
The oxytocin (OXT) system has garnered considerable interest due to its influence on diverse behaviours. However, scant research has considered the influence of oxytocin on sleep-wake and sleep-related behaviour and neurobiology. Consequently, the objective of this systematic review was to assess the extant preclinical and clinical evidence for the influence of oxytocin-based interventions on sleep-wake outcomes. The primary search was conducted on 22/7/2020 using six electronic databases; 30 studies (19 preclinical, 11 clinical) were included based on inclusion criteria. Studies were evaluated for risk of bias using the SYRCLE tool and the Cochrane risk of bias tools for preclinical and clinical studies, respectively. Results indicated manipulation of the OXT system can influence sleep-wake outcomes. Preclinical evidence suggests a wake-promoting influence of OXT system activation whereas the clinical evidence suggests little or no sleep-promoting influence of OXT. OXT dose was identified as a likely modulatory factor of OXT-induced effects on sleep-wake behaviour. Future studies are necessary to validate and strengthen these tentative conclusions about the influence of OXT on sleep-wake behaviour.
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Affiliation(s)
- Joel S Raymond
- The University of Sydney, Faculty of Science, School of Psychology, Camperdown, NSW, Australia; The University of Sydney, Brain and Mind Centre, Camperdown, NSW, Australia
| | - Simone Rehn
- The University of Sydney, Faculty of Science, School of Psychology, Camperdown, NSW, Australia
| | - Camilla M Hoyos
- The University of Sydney, Faculty of Science, School of Psychology, Camperdown, NSW, Australia; The University of Sydney, Brain and Mind Centre, Camperdown, NSW, Australia; The University of Sydney, Woolcock Institute of Medical Research, Centre for Sleep and Chronobiology, Camperdown, NSW, Australia
| | - Michael T Bowen
- The University of Sydney, Faculty of Science, School of Psychology, Camperdown, NSW, Australia; The University of Sydney, Brain and Mind Centre, Camperdown, NSW, Australia.
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11
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Geoffroy PA, Oquendo MA, Courtet P, Blanco C, Olfson M, Peyre H, Lejoyeux M, Limosin F, Hoertel N. Sleep complaints are associated with increased suicide risk independently of psychiatric disorders: results from a national 3-year prospective study. Mol Psychiatry 2021; 26:2126-2136. [PMID: 32355334 DOI: 10.1038/s41380-020-0735-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/06/2020] [Accepted: 04/14/2020] [Indexed: 12/21/2022]
Abstract
Prior research suggests that sleep disturbances are associated with increased risk of suicide. However, sleep disturbances are associated with a wide range of psychiatric disorders, and it is unknown whether this association is independent of psychopathology. In a large nationally representative prospective survey, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), we used structural equation modeling to examine the shared and specific effects of three sleep complaints (i.e., trouble falling asleep, early morning awakening, and hypersomnia) on the 3-year occurrence of attempting suicide. Because psychiatric disorders increase the risk of suicide attempt almost exclusively through a general psychopathology factor representing their shared effect, covariates included that factor, prior history of suicide attempt, and a wide range of sociodemographic and clinical characteristics. The 3-year prevalence rate of suicide attempt was 0.6% (n = 241). Compared with participants who did not attempt suicide between the two waves, those who did reported significantly more frequently having trouble falling asleep (44.6% vs. 16.6%), early morning awakening (38.9% vs. 12.7%), and hypersomnia (35.0% vs. 10.7%). Following adjustments, effects of sleep complaints on this risk were significant and exerted almost exclusively through a general sleep complaints factor representing the shared effect across all sleep complaints. There were no residual associations of any individual sleep complaint with attempting suicide above that association. Sleep complaints are associated with an increased risk of attempting suicide independently of psychopathology, and should be included in suicide risk assessments as these symptoms may provide targets for reducing the risks of suicidal behaviors.
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Affiliation(s)
- Pierre A Geoffroy
- Paris Diderot University-Paris VII, 5 Rue Thomas Mann, 75013, Paris, France. .,Université de Paris, NeuroDiderot, Inserm, F-75019, Paris, France. .,University Hospital Bichat-Claude Bernard, 46 rue Henri Huchard, 75018, Paris, France.
| | - Maria A Oquendo
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Philippe Courtet
- INSERM, U1061, Neuropsychiatry, University Montpellier, Montpellier, France.,Department of Emergency Psychiatry and Post-Acute Care, CHU Montpellier, Montpellier, France
| | - Carlos Blanco
- Division of Epidemiology, Services, and Prevention Research, National Institute on Drug Abuse, Bethesda, MD, USA
| | - Mark Olfson
- Department of Psychiatry, New York State Psychiatric Institute/Columbia University, New York, NY, 10032, USA
| | - Hugo Peyre
- Assistance Publique-Hôpitaux de Paris, Robert Debré Hospital, Child and Adolescent Psychiatry Department, Paris, France.,Cognitive Sciences and Psycholinguistic Laboratory, Ecole Normale Supérieure, Paris, France
| | - Michel Lejoyeux
- Paris Diderot University-Paris VII, 5 Rue Thomas Mann, 75013, Paris, France.,University Hospital Bichat-Claude Bernard, 46 rue Henri Huchard, 75018, Paris, France
| | - Frédéric Limosin
- Cognitive Sciences and Psycholinguistic Laboratory, Ecole Normale Supérieure, Paris, France.,Centre Ressource Régional de Psychiatrie du Sujet Agé (CRRPSA), Service de Psychiatrie et d'Addictologie de l'adulte et du sujet âgé, DMU Psychiatrie et Addictologie, AP-HP.Centre-Université de Paris, Paris, France.,Faculté de médecine Paris Descartes, Université de Paris, Paris, France.,Inserm U1266, Institut de Psychiatrie et Neurosciences de Paris, Paris, France
| | - Nicolas Hoertel
- Cognitive Sciences and Psycholinguistic Laboratory, Ecole Normale Supérieure, Paris, France.,Centre Ressource Régional de Psychiatrie du Sujet Agé (CRRPSA), Service de Psychiatrie et d'Addictologie de l'adulte et du sujet âgé, DMU Psychiatrie et Addictologie, AP-HP.Centre-Université de Paris, Paris, France.,Faculté de médecine Paris Descartes, Université de Paris, Paris, France.,Inserm U1266, Institut de Psychiatrie et Neurosciences de Paris, Paris, France
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12
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Ballaz S, Espinosa N, Bourin M. Does endogenous cholecystokinin modulate alcohol intake? Neuropharmacology 2021; 193:108539. [PMID: 33794246 DOI: 10.1016/j.neuropharm.2021.108539] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/06/2021] [Accepted: 03/22/2021] [Indexed: 02/08/2023]
Abstract
Alcohol use disorder or alcoholism is characterized by uncontrollable alcohol use and intoxication, as well as a heightened state of anxiety after alcohol withdrawal. Ethanol-associated stimuli also drive the urge to drink by means of classical conditioning. Alcoholism has been considered a dopamine (DA) dysregulation syndrome that involves the activity of the central amygdala circuitry of anxiety. Cholecystokinin (CCK) is the most abundant neuropeptide in the mammal brain, where it activates two receptors, CCK1 and CCK2. Genetic evidence relates CCK1 receptors to alcoholism in humans. CCK2 activity has been associated with the onset of human anxiety. CCK modulates DA release in the nucleus accumbens (NAc) and it is expressed in the γ-aminobutyric acid (GABA)-expressing basket interneurons in the cerebral cortex. CCK interacts with serotonin (5-HT) neurotransmission through 5-HT3 receptors to regulate mesocorticolimbic pathways and with GABA to attenuate anxiety in the amygdala. Finally, CCK stimulates the release of orexins and oxytocin in the hypothalamus, two relevant hypothalamic neuropeptides involved in signaling satiety for ethanol and well-being respectively. Given the "dimmer-switch" function of endogenous CCK in the neurotransmission by 5-HT, DA, GABA, and glutamate in normal and pathological behaviors (Ballaz and Bourin, 2020), we hypothesize that CCK adjusts functioning of the reward and anxiety circuitries altered by ethanol. This review gathers data supporting this hypothesis, and suggests mechanisms underlying a role for endogenous CCK in alcoholism.
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Affiliation(s)
- Santiago Ballaz
- School of Biological Sciences & Engineering, Yachay Tech University, Hacienda San José s/n, San Miguel de Urcuquí, Ecuador; School of Medicine, Universidad Espíritu Santo, Samborondón, Ecuador.
| | - Nicole Espinosa
- School of Biological Sciences & Engineering, Yachay Tech University, Hacienda San José s/n, San Miguel de Urcuquí, Ecuador.
| | - Michel Bourin
- Neurobiology of Anxiety and Mood Disorders, University of Nantes, 98, Rue Joseph Blanchart, 44100 Nantes, France.
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13
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Peng Q, Weng K, Li S, Xu R, Wang Y, Wu Y. A Perspective of Epigenetic Regulation in Radiotherapy. Front Cell Dev Biol 2021; 9:624312. [PMID: 33681204 PMCID: PMC7930394 DOI: 10.3389/fcell.2021.624312] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/28/2021] [Indexed: 12/17/2022] Open
Abstract
Radiation therapy (RT) has been employed as a tumoricidal modality for more than 100 years and on 470,000 patients each year in the United States. The ionizing radiation causes genetic changes and results in cell death. However, since the biological mechanism of radiation remains unclear, there is a pressing need to understand this mechanism to improve the killing effect on tumors and reduce the side effects on normal cells. DNA break and epigenetic remodeling can be induced by radiotherapy. Hence the modulation of histone modification enzymes may tune the radiosensitivity of cancer cells. For instance, histone deacetylase (HDAC) inhibitors sensitize irradiated cancer cells by amplifying the DNA damage signaling and inhibiting double-strand DNA break repair to influence the irradiated cells’ survival. However, the combination of epigenetic drugs and radiotherapy has only been evaluated in several ongoing clinical trials for limited cancer types, partly due to a lack of knowledge on the potential mechanisms on how radiation induces epigenetic regulation and chromatin remodeling. Here, we review recent advances of radiotherapy and radiotherapy-induced epigenetic remodeling and introduce related technologies for epigenetic monitoring. Particularly, we exploit the application of fluorescence resonance energy transfer (FRET) biosensors to visualize dynamic epigenetic regulations in single living cells and tissue upon radiotherapy and drug treatment. We aim to bridge FRET biosensor, epigenetics, and radiotherapy, providing a perspective of using FRET to assess epigenetics and provide guidance for radiotherapy to improve cancer treatment. In the end, we discuss the feasibility of a combination of epigenetic drugs and radiotherapy as new approaches for cancer therapeutics.
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Affiliation(s)
- Qin Peng
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China.,Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Kegui Weng
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States.,Chongqing Cancer Hospital, Chongqing Cancer Institute, Chongqing University Cancer Hospital, Chongqing, China
| | - Shitian Li
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Richard Xu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Yingxiao Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Yongzhong Wu
- Chongqing Cancer Hospital, Chongqing Cancer Institute, Chongqing University Cancer Hospital, Chongqing, China
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14
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Sagi D, de Lecea L, Appelbaum L. Heterogeneity of Hypocretin/Orexin Neurons. FRONTIERS OF NEUROLOGY AND NEUROSCIENCE 2021; 45:61-74. [PMID: 34052814 PMCID: PMC8961008 DOI: 10.1159/000514964] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/02/2021] [Indexed: 01/21/2023]
Abstract
The multifunctional, hypothalamic hypocretin/orexin (HCRT)-producing neurons regulate an array of physiological and behavioral states including arousal, sleep, feeding, emotions, stress, and reward. How a presumably uniform HCRT neuron population regulates such a diverse set of functions is not clear. The role of the HCRT neuropeptides may vary depending on the timing and localization of secretion and neuronal activity. Moreover, HCRT neuropeptides may not mediate all functions ascribed to HCRT neurons. Some could be orchestrated by additional neurotransmitters and neuropeptides that are expressed in HCRT neurons. We hypothesize that HCRT neurons are segregated into genetically, anatomically and functionally distinct subpopulations. We discuss accumulating data that suggest the existence of such HCRT neuron subpopulations that may effectuate the diverse functions of these neurons in mammals and fish.
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Affiliation(s)
- Dana Sagi
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Luis de Lecea
- Dept of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Lior Appelbaum
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel.,Corresponding author: Lior Appelbaum, Bar-Ilan University, Ramat-Gan 5290002, Israel. Telephone: +972-3-7384536,
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15
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Lee J, Raycraft L, Johnson AW. The dynamic regulation of appetitive behavior through lateral hypothalamic orexin and melanin concentrating hormone expressing cells. Physiol Behav 2020; 229:113234. [PMID: 33130035 DOI: 10.1016/j.physbeh.2020.113234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
The lateral hypothalamic area (LHA) is a heterogeneous brain structure extensively studied for its potent role in regulating energy balance. The anatomical and molecular diversity of the LHA permits the orchestration of responses to energy sensing cues from the brain and periphery. Two of the primary cell populations within the LHA associated with integration of this information are Orexin (ORX) and Melanin Concentrating Hormone (MCH). While both of these non-overlapping populations exhibit orexigenic properties, the activities of these two systems support feeding behavior through contrasting mechanisms. We describe the anatomical and functional properties as well as interaction with other neuropeptides and brain reward and hedonic systems. Specific outputs relating to arousal, food seeking, feeding, and metabolism are coordinated through these mechanisms. We then discuss how both the ORX and MCH systems harmonize in a divergent yet overall cooperative manner to orchestrate feeding behavior through transitions between various appetitive states, and thus offer novel insights into LHA allostatic control of appetite.
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Affiliation(s)
| | | | - Alexander W Johnson
- Department of Psychology; Neuroscience Program, Michigan State University, East Lansing.
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16
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Li Y, Cui ZJ. NanoLuc Bioluminescence-Driven Photodynamic Activation of Cholecystokinin 1 Receptor with Genetically-Encoded Protein Photosensitizer MiniSOG. Int J Mol Sci 2020; 21:ijms21113763. [PMID: 32466589 PMCID: PMC7313028 DOI: 10.3390/ijms21113763] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/21/2020] [Accepted: 05/25/2020] [Indexed: 02/07/2023] Open
Abstract
In contrast to reversible activation by agonist, cholecystokinin 1 receptor (CCK1R) is permanently activated by singlet oxygen generated in photodynamic action, with sulphonated aluminium phthalocyanine or genetically encoded mini singlet oxygen generator (miniSOG) as photosensitizer. In these works, a halogen light source was used to power photodynamic action. For possible in vivo application of photodynamic CCK1R physiology, bearing a cumbersome light-delivery device connected to an external light source by experimental animals might interfere with their behavior. Therefore, in the present work, the possibility of bioluminescence-driven miniSOG photodynamic CCK1R activation was examined, as monitored by Fura-2 calcium imaging. In parallel experiments, it was found that, after plasma membrane (PM)-localized expression of miniSOGPM in AR4-2J cells, light irradiation with blue light-emitting diode (LED) (450 nm, 85 mW·cm-2, 1.5 min) induced persistent calcium oscillations that were blocked by CCK1R antagonist devazepide 2 nM. NanoLuc was expressed bicistronically with miniSOGPM via an internal ribosome entry site (IRES) sequence (pminiSOGPM-IRES-NanoLuc). The resultant miniSOGPM-IRES-NanoLuc-AR4-2J cells were found to generate strong bioluminescence upon addition of NanoLuc substrate coelenterazine. Strikingly, coelenterazine 5 microM was found to trigger long-lasting calcium oscillations (a hallmark for permanent CCK1R activation) in perifused miniSOGPM-IRES-NanoLuc-AR4-2J cells. These data indicate that NanoLuc bioluminescence can drive miniSOGPM photodynamic CCK1R activation, laying the foundation for its future in vivo applications.
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17
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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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18
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Li Y, Iida H, Kimata K, Zhuo L, Ota A, Kimura S, Yin X, Deie M, Ushida T. Establishment of a mouse model for injury-induced scar formation and the accompanying chronic pain: Comprehensive microarray analysis of molecular expressions in fibrosis and hyperalgesia. Mol Pain 2019; 15:1744806919892389. [PMID: 31749400 PMCID: PMC6997725 DOI: 10.1177/1744806919892389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Surgery is often accompanied by scar formation, which results in a
pathological state called fibrosis. Fibrosis is characterized by the excess
deposition of extracellular matrix molecules in the connective tissue,
leading to tissue contracture and chronic pain. To understand the molecular
mechanisms underlying these processes and their causative relationships, we
performed comprehensive analyses of gene expression changes in the hind paw
tissue of a mouse model established by generating a scar in the sole. Results Subcutaneous tissue was extensively stripped from the sole of the operation
group mice, while a needle was inserted in the sole of the sham group mice.
Pain threshold, as evaluated by mechanical stimulation with von Frey fiber,
decreased rapidly in the operated (ipsilateral) paw and a day later in the
nonoperated (contralateral) paw. The reductions were maintained for more
than three weeks, suggesting that chronic pain spread to the other tissues
via the central nervous system. RNA from the paw and the dorsal root
ganglion (L3–L5) tissues were subjected to microarray analyses one and two
weeks following the operation. The expressions of a number of genes,
especially those coding for extracellular matrix molecules and peripheral
perceptive nerve receptors, were altered in the operation group mice paw
tissues. The expression of few genes was altered in the dorsal root ganglion
tissues; distinct upregulation of some nociceptive genes such as
cholecystokinin B receptor was observed. Results of real-time polymerase
chain reaction and immune and histochemical staining of some of the gene
products confirmed the results of the microarray analysis. Conclusion Analyses using a novel mouse model revealed the extensive involvement of
extracellular matrix-related genes and peripheral perceptive nerve receptor
genes resulting in scar formation with chronic pain. Future bioinformatics
analyses will explore the association between these relationships.
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Affiliation(s)
- Yuqiang Li
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, School of Physical Education and Health, East China Normal University, Shanghai, China.,Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Japan
| | - Hiroki Iida
- Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Japan
| | - Koji Kimata
- Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Japan
| | - Lisheng Zhuo
- Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Japan
| | - Akinobu Ota
- Department of Biochemistry, Aichi Medical University, Nagakute, Japan
| | - Shinya Kimura
- Department of Rehabilitation Medicine, Aichi Medical University, Nagakute, Japan
| | - Xiaojian Yin
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, School of Physical Education and Health, East China Normal University, Shanghai, China
| | - Masataka Deie
- Department of Orthopaedic Surgery, Aichi Medical University, Nagakute, Japan
| | - Takahiro Ushida
- Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Japan
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19
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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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20
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Wang R, Lu Y, Cicha MZ, Singh MV, Benson CJ, Madden CJ, Chapleau MW, Abboud FM. TMEM16B determines cholecystokinin sensitivity of intestinal vagal afferents of nodose neurons. JCI Insight 2019; 4:122058. [PMID: 30843875 DOI: 10.1172/jci.insight.122058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 01/17/2019] [Indexed: 12/11/2022] Open
Abstract
The satiety effects and metabolic actions of cholecystokinin (CCK) have been recognized as potential therapeutic targets in obesity for decades. We identified a potentially novel Ca2+-activated chloride (Cl-) current (CaCC) that is induced by CCK in intestinal vagal afferents of nodose neurons. The CaCC subunit Anoctamin 2 (Ano2/TMEM16B) is the dominant contributor to this current. Its expression is reduced, as is CCK current activity in obese mice on a high-fat diet (HFD). Reduced expression of TMEM16B in the heterozygote KO of the channel in sensory neurons results in an obese phenotype with a loss of CCK sensitivity in intestinal nodose neurons, a loss of CCK-induced satiety, and metabolic changes, including decreased energy expenditure. The effect on energy expenditure is further supported by evidence in rats showing that CCK enhances sympathetic nerve activity and thermogenesis in brown adipose tissue, and these effects are abrogated by a HFD and vagotomy. Our findings reveal that Ano2/TMEM16B is a Ca2+-activated chloride channel in vagal afferents of nodose neurons and a major determinant of CCK-induced satiety, body weight control, and energy expenditure, making it a potential therapeutic target in obesity.
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Affiliation(s)
- Runping Wang
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Yongjun Lu
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Michael Z Cicha
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Madhu V Singh
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Christopher J Benson
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, USA
| | - Mark W Chapleau
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - François M Abboud
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
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21
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Giardino WJ, Eban-Rothschild A, Christoffel DJ, Li SB, Malenka RC, de Lecea L. Parallel circuits from the bed nuclei of stria terminalis to the lateral hypothalamus drive opposing emotional states. Nat Neurosci 2018; 21:1084-1095. [PMID: 30038273 PMCID: PMC6095688 DOI: 10.1038/s41593-018-0198-x] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 06/12/2018] [Indexed: 12/15/2022]
Abstract
Lateral hypothalamus (LH) neurons containing the neuropeptide hypocretin (HCRT; orexin) modulate affective components of arousal, but their relevant synaptic inputs remain poorly defined. Here we identified inputs onto LH neurons that originate from neuronal populations in the bed nuclei of stria terminalis (BNST; a heterogeneous region of extended amygdala). We characterized two non-overlapping LH-projecting GABAergic BNST subpopulations that express distinct neuropeptides (corticotropin-releasing factor, CRF, and cholecystokinin, CCK). To functionally interrogate BNST→LH circuitry, we used tools for monitoring and manipulating neural activity with cell-type-specific resolution in freely behaving mice. We found that Crf-BNST and Cck-BNST neurons respectively provide abundant and sparse inputs onto Hcrt-LH neurons, display discrete physiological responses to salient stimuli, drive opposite emotionally valenced behaviors, and receive different proportions of inputs from upstream networks. Together, our data provide an advanced model for how parallel BNST→LH pathways promote divergent emotional states via connectivity patterns of genetically defined, circuit-specific neuronal subpopulations.
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Affiliation(s)
- William J Giardino
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Ada Eban-Rothschild
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Daniel J Christoffel
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Shi-Bin Li
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Robert C Malenka
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Luis de Lecea
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA.
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22
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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: 26] [Impact Index Per Article: 4.3] [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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23
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Barson JR, Leibowitz SF. Orexin/Hypocretin System: Role in Food and Drug Overconsumption. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 136:199-237. [PMID: 29056152 DOI: 10.1016/bs.irn.2017.06.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The neuropeptide orexin/hypocretin (OX), while largely transcribed within the hypothalamus, is released throughout the brain to affect complex behaviors. Primarily through the hypothalamus itself, OX homeostatically regulates adaptive behaviors needed for survival, including food intake, sleep-wake regulation, mating, and maternal behavior. However, through extrahypothalamic limbic brain regions, OX promotes seeking and intake of rewarding substances of abuse, like palatable food, alcohol, nicotine, and cocaine. This neuropeptide, in turn, is stimulated by the intake of or early life exposure to these substances, forming a nonhomeostatic, positive feedback loop. The specific OX receptor involved in these behaviors, whether adaptive behavior or substance seeking and intake, is dependent on the particular brain region that contributes to them. Thus, we propose that, while the primary function of OX is to maintain arousal for the performance of adaptive behaviors, this neuropeptide system is readily co-opted by rewarding substances that involve positive feedback, ultimately promoting their abuse.
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Affiliation(s)
- Jessica R Barson
- Drexel University College of Medicine, Philadelphia, PA, United States
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24
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Ballaz S. The unappreciated roles of the cholecystokinin receptor CCK(1) in brain functioning. Rev Neurosci 2017; 28:573-585. [DOI: 10.1515/revneuro-2016-0088] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/05/2017] [Indexed: 12/13/2022]
Abstract
AbstractThe CCK(1) receptor is a G-protein-coupled receptor activated by the sulfated forms of cholecystokinin (CCK), a gastrin-like peptide released in the gastrointestinal tract and mammal brain. A substantial body of research supports the hypothesis that CCK(1)r stimulates gallbladder contraction and pancreatic secretion in the gut, as well as satiety in brain. However, this receptor may also fulfill relevant roles in behavior, thanks to its widespread distribution in the brain. The strategic location of CCK(1)r in mesolimbic structures and specific hypothalamic and brainstem nuclei lead to complex interactions with neurotransmitters like dopamine, serotonin, and glutamate, as well as hypothalamic hormones and neuropeptides. The activity of CCK(1)r maintains adequate levels of dopamine and regulates the activity of serotonin neurons of raphe nuclei, which makes CCK(1)r an interesting therapeutic target for the development of adjuvant treatments for schizophrenia, drug addiction, and mood disorders. Unexplored functions of CCK(1)r, like the transmission of interoceptive sensitivity in addition to the regulation of hypothalamic hormones and neurotransmitters affecting emotional states, well-being, and attachment behaviors, may open exciting roads of research. The absence of specific ligands for the CCK(1) receptor has complicated the study of its distribution in brain so that research about its impact on behavior has been published sporadically over the last 30 years. The present review reunites all this body of evidence in a comprehensive way to summarize our knowledge about the actual role of CCK in the neurobiology of mental illness.
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Affiliation(s)
- Santiago Ballaz
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San Jose y Proyecto Yachay s/n, San Miguel de Urcuquí 100119, Ecuador
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25
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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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26
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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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27
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Calvigioni D, Máté Z, Fuzik J, Girach F, Zhang MD, Varro A, Beiersdorf J, Schwindling C, Yanagawa Y, Dockray GJ, McBain CJ, Hökfelt T, Szabó G, Keimpema E, Harkany T. Functional Differentiation of Cholecystokinin-Containing Interneurons Destined for the Cerebral Cortex. Cereb Cortex 2017; 27:2453-2468. [PMID: 27102657 DOI: 10.1093/cercor/bhw094] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Although extensively studied postnatally, the functional differentiation of cholecystokinin (CCK)-containing interneurons en route towards the cerebral cortex during fetal development is incompletely understood. Here, we used CCKBAC/DsRed mice encoding a CCK promoter-driven red fluorescent protein to analyze the temporal dynamics of DsRed expression, neuronal identity, and positioning through high-resolution developmental neuroanatomy. Additionally, we developed a dual reporter mouse line (CCKBAC/DsRed::GAD67gfp/+) to differentiate CCK-containing interneurons from DsRed+ principal cells during prenatal development. We show that DsRed is upregulated in interneurons once they exit their proliferative niche in the ganglionic eminence and remains stably expressed throughout their long-distance migration towards the cerebrum, particularly in the hippocampus. DsRed+ interneurons, including a cohort coexpressing calretinin, accumulated at the palliosubpallial boundary by embryonic day 12.5. Pioneer DsRed+ interneurons already reached deep hippocampal layers by embryonic day 14.5 and were morphologically differentiated by birth. Furthermore, we probed migrating interneurons entering and traversing the cortical plate, as well as stationary cells in the hippocampus by patch-clamp electrophysiology to show the first signs of Na+ and K+ channel activity by embryonic day 12.5 and reliable adult-like excitability by embryonic day 18.5. Cumulatively, this study defines key positional, molecular, and biophysical properties of CCK+ interneurons in the prenatal brain.
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Affiliation(s)
- Daniela Calvigioni
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Scheeles väg 1
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
| | - Zoltán Máté
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083 Budapest, Hungary
| | - János Fuzik
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
| | - Fatima Girach
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
| | - Ming-Dong Zhang
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Scheeles väg 1
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-17177 Stockholm, Sweden
| | - Andrea Varro
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, L69 3BX Liverpool, UK
| | - Johannes Beiersdorf
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
| | - Christian Schwindling
- Microscopy Labs Munich, Global Sales Support-Life Sciences, Carl Zeiss Microscopy GmbH, Kistlerhofstrasse 75, D-81379 Munich, Germany
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
| | - Graham J Dockray
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-17177 Stockholm, Sweden
| | - Chris J McBain
- Program in Developmental Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-17177 Stockholm, Sweden
| | - Gábor Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083 Budapest, Hungary
| | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Scheeles väg 1
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
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28
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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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29
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Schöne C, Burdakov D. Orexin/Hypocretin and Organizing Principles for a Diversity of Wake-Promoting Neurons in the Brain. Curr Top Behav Neurosci 2017; 33:51-74. [PMID: 27830577 PMCID: PMC5767105 DOI: 10.1007/7854_2016_45] [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] [Indexed: 12/26/2022]
Abstract
An enigmatic feature of behavioural state control is the rich diversity of wake-promoting neural systems. This diversity has been rationalized as 'robustness via redundancy', wherein wakefulness control is not critically dependent on one type of neuron or molecule. Studies of the brain orexin/hypocretin system challenge this view by demonstrating that wakefulness control fails upon loss of this neurotransmitter system. Since orexin neurons signal arousal need, and excite other wake-promoting neurons, their actions illuminate nonredundant principles of arousal control. Here, we suggest such principles by reviewing the orexin system from a collective viewpoint of biology, physics and engineering. Orexin peptides excite other arousal-promoting neurons (noradrenaline, histamine, serotonin, acetylcholine neurons), either by activating mixed-cation conductances or by inhibiting potassium conductances. Ohm's law predicts that these opposite conductance changes will produce opposite effects on sensitivity of neuronal excitability to current inputs, thus enabling orexin to differentially control input-output gain of its target networks. Orexin neurons also produce other transmitters, including glutamate. When orexin cells fire, glutamate-mediated downstream excitation displays temporal decay, but orexin-mediated excitation escalates, as if orexin transmission enabled arousal controllers to compute a time integral of arousal need. Since the anatomical and functional architecture of the orexin system contains negative feedback loops (e.g. orexin ➔ histamine ➔ noradrenaline/serotonin-orexin), such computations may stabilize wakefulness via integral feedback, a basic engineering strategy for set point control in uncertain environments. Such dynamic behavioural control requires several distinct wake-promoting modules, which perform nonredundant transformations of arousal signals and are connected in feedback loops.
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Affiliation(s)
- Cornelia Schöne
- Department of Neurology, University of Bern, Bern University Hospital, 3010, Bern, Switzerland
| | - Denis Burdakov
- The Francis Crick Institute, Mill Hill Laboratory, London, NW7 1AA, UK.
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30
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Bonnavion P, Mickelsen LE, Fujita A, de Lecea L, Jackson AC. Hubs and spokes of the lateral hypothalamus: cell types, circuits and behaviour. J Physiol 2016; 594:6443-6462. [PMID: 27302606 DOI: 10.1113/jp271946] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 05/31/2016] [Indexed: 12/13/2022] Open
Abstract
The hypothalamus is among the most phylogenetically conserved regions in the vertebrate brain, reflecting its critical role in maintaining physiological and behavioural homeostasis. By integrating signals arising from both the brain and periphery, it governs a litany of behaviourally important functions essential for survival. In particular, the lateral hypothalamic area (LHA) is central to the orchestration of sleep-wake states, feeding, energy balance and motivated behaviour. Underlying these diverse functions is a heterogeneous assembly of cell populations typically defined by neurochemical markers, such as the well-described neuropeptides hypocretin/orexin and melanin-concentrating hormone. However, anatomical and functional evidence suggests a rich diversity of other cell populations with complex neurochemical profiles that include neuropeptides, receptors and components of fast neurotransmission. Collectively, the LHA acts as a hub for the integration of diverse central and peripheral signals and, through complex local and long-range output circuits, coordinates adaptive behavioural responses to the environment. Despite tremendous progress in our understanding of the LHA, defining the identity of functionally discrete LHA cell types, and their roles in driving complex behaviour, remain significant challenges in the field. In this review, we discuss advances in our understanding of the neurochemical and cellular heterogeneity of LHA neurons and the recent application of powerful new techniques, such as opto- and chemogenetics, in defining the role of LHA circuits in feeding, reward, arousal and stress. From pioneering work to recent developments, we review how the interrogation of LHA cells and circuits is contributing to a mechanistic understanding of how the LHA coordinates complex behaviour.
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Affiliation(s)
- Patricia Bonnavion
- Laboratory of Neurophysiology, Université Libre de Bruxelles (ULB)-UNI, 1050, Brussels, Belgium
| | - Laura E Mickelsen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Akie Fujita
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioural Sciences, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
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31
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Tominaga M, Momonaka Y, Yokose C, Tadaishi M, Shimizu M, Yamane T, Oishi Y, Kobayashi-Hattori K. Anorexic action of deoxynivalenol in hypothalamus and intestine. Toxicon 2016; 118:54-60. [PMID: 27090011 DOI: 10.1016/j.toxicon.2016.04.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/14/2016] [Indexed: 12/18/2022]
Abstract
Although deoxynivalenol (DON) suppresses food intake and subsequent weight gain, its contribution to anorexia mechanisms has not been fully clarified. Thus, we investigated the anorexic actions of DON in the hypothalamus and intestine, both organs related to appetite. When female B6C3F1 mice were orally exposed to different doses of DON, a drastic anorexic action was observed at a dose of 12.5 mg/kg body weight (bw) from 0 to 3 h after administration. Exposure to DON (12.5 mg/kg bw) for 3 h significantly increased the hypothalamic mRNA levels of anorexic pro-opiomelanocortin (POMC) and its downstream targets, including melanocortin 4 receptor, brain-derived neurotrophic factor, and tyrosine kinase receptor B; at the same time, orexigenic hormones were not affected. In addition, exposure to DON significantly elevated the hypothalamic mRNA levels of proinflammatory cytokines (IL-1β, TNF-α, and IL-6) and activated nuclear factor-kappa B (NF-κB), an upstream factor of POMC. These results suggest that DON-induced proinflammatory cytokines increased the POMC level via NF-κB activation. Moreover, exposure to DON significantly enhanced the gastrointestinal mRNA levels of anorexic cholecystokinin (CCK) and transient receptor potential ankyrin-1 channel (TRPA1), a possible target of DON; these findings suggest that DON induced anorexic action by increasing CCK production via TRPA1. Taken together, these results suggest that DON induces anorexic POMC, perhaps via NF-κB activation, by increasing proinflammatory cytokines in the hypothalamus and brings about CCK production, possibly through increasing intestinal TRPA1 expression, leading to anorexic actions.
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Affiliation(s)
- Misa Tominaga
- Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Yuka Momonaka
- Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Chihiro Yokose
- Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Miki Tadaishi
- Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Makoto Shimizu
- Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Takumi Yamane
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Yuichi Oishi
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Kazuo Kobayashi-Hattori
- Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
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32
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Abstract
The hypocretins (Hcrts), also known as orexins, have been among the most intensely studied neuropeptide systems since their discovery about two decades ago. Anatomical evidence shows that the hypothalamic neurons that produce hypocretins/orexins project widely throughout the entire brain, innervating the noradrenergic locus coeruleus, the cholinergic basal forebrain, the dopaminergic ventral tegmental area, the serotonergic raphe nuclei, the histaminergic tuberomammillary nucleus, and many other brain regions. By interacting with other neural systems, the Hcrt system profoundly modulates versatile physiological processes including arousal, food intake, emotion, attention, and reward. Importantly, interruption of the interactions between these systems has the potential to cause neurological and psychiatric diseases. Here, we review the modulation of diverse neural systems by Hcrts and summarize potential therapeutic strategies based on our understanding of the Hcrt system's role in physiology and pathophysiological processes.
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33
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Abstract
Genetically-encoded fluorescence resonance energy transfer (FRET) reporters are powerful tools to analyze cell signaling and function at single cell resolution in standard two-dimensional cell cultures, but these reporters rarely have been applied to three-dimensional environments. FRET interactions between donor and acceptor molecules typically are determined by changes in relative fluorescence intensities, but wavelength-dependent differences in absorption of light complicate this analysis method in three-dimensional settings. Here we report fluorescence lifetime imaging microscopy (FLIM) with phasor analysis, a method that displays fluorescence lifetimes on a pixel-wise basis in real time, to quantify apoptosis in breast cancer cells stably expressing a genetically encoded FRET reporter. This microscopic imaging technology allowed us to identify treatment-induced apoptosis in single breast cancer cells in environments ranging from two-dimensional cell culture, spheroids with cancer and bone marrow stromal cells, and living mice with orthotopic human breast cancer xenografts. Using this imaging strategy, we showed that combined metabolic therapy targeting glycolysis and glutamine pathways significantly reduced overall breast cancer metabolism and induced apoptosis. We also determined that distinct subpopulations of bone marrow stromal cells control resistance of breast cancer cells to chemotherapy, suggesting heterogeneity of treatment responses of malignant cells in different bone marrow niches. Overall, this study establishes FLIM with phasor analysis as an imaging tool for apoptosis in cell-based assays and living mice, enabling real-time, cellular-level assessment of treatment efficacy and heterogeneity.
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Affiliation(s)
| | | | | | - Gary D. Luker
- Microbiology and Immunology, University of Michigan, Ann Arbor, MI
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Abstract
Cortical electroencephalographic activity arises from corticothalamocortical interactions, modulated by wake-promoting monoaminergic and cholinergic input. These wake-promoting systems are regulated by hypothalamic hypocretin/orexins, while GABAergic sleep-promoting nuclei are found in the preoptic area, brainstem and lateral hypothalamus. Although pontine acetylcholine is critical for REM sleep, hypothalamic melanin-concentrating hormone/GABAergic cells may "gate" REM sleep. Daily sleep-wake rhythms arise from interactions between a hypothalamic circadian pacemaker and a sleep homeostat whose anatomical locus has yet to be conclusively defined. Control of sleep and wakefulness involves multiple systems, each of which presents vulnerability to sleep/wake dysfunction that may predispose to physical and/or neuropsychiatric disorders.
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Affiliation(s)
- Michael D Schwartz
- Biosciences Division, Center for Neuroscience, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA
| | - Thomas S Kilduff
- Biosciences Division, Center for Neuroscience, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA.
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Abstract
Sleep and wake are fundamental behavioral states whose molecular regulation remains mysterious. Brain states and body functions change dramatically between sleep and wake, are regulated by circadian and homeostatic processes, and depend on the nutritional and emotional condition of the animal. Sleep-wake transitions require the coordination of several brain regions and engage multiple neurochemical systems, including neuropeptides. Neuropeptides serve two main functions in sleep-wake regulation. First, they represent physiological states such as energy level or stress in response to environmental and internal stimuli. Second, neuropeptides excite or inhibit their target neurons to induce, stabilize, or switch between sleep-wake states. Thus, neuropeptides integrate physiological subsystems such as circadian time, previous neuron usage, energy homeostasis, and stress and growth status to generate appropriate sleep-wake behaviors. We review the roles of more than 20 neuropeptides in sleep and wake to lay the foundation for future studies uncovering the mechanisms that underlie the initiation, maintenance, and exit of sleep and wake states.
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Affiliation(s)
- Constance Richter
- Department of Molecular and Cellular Biology, Center for Brain Science, Division of Sleep Biology, Harvard University, Cambridge, Massachusetts 02138; ,
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Xie XS. The neuronal circuit between nociceptin/orphanin FQ and hypocretins/orexins coordinately modulates stress-induced analgesia and anxiety-related behavior. VITAMINS AND HORMONES 2015; 97:295-321. [PMID: 25677777 DOI: 10.1016/bs.vh.2014.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The neuropeptide nociceptin/orphanin FQ (N/OFQ), acting on its receptors (NOP), modulates a variety of biological functions and neurobehavior including nociception, stress responses, water and food-intake, locomotor activity, and spatial attention. N/OFQ is conventionally regarded as an "antiopiate" peptide in the brain because central administration of N/OFQ attenuates stress-induced analgesia (SIA) and produces anxiolytic effects. However, naloxone-irreversible SIA and anxiolytic action are unlikely to be mediated by the opiate system. Both N/OFQ and NOP receptors are expressed most abundantly in the hypothalamus, where two other neuropeptides, the hypocretins/orexins (Hcrts), are exclusively synthesized in the lateral hypothalamic area. N/OFQ and Hcrt regulate most cellular physiological responses in opposite directions (e.g., ion channel modulation and second messenger coupling), and produce differential modulations for almost all neurobehavior assessed, including sleep/wake, locomotion, and rewarding behaviors. This chapter focuses on recent studies that provide evidence at a neuroanatomical level showing that a local neuronal circuit linking N/OFQ to Hcrt neurons exists. Functionally, N/OFQ depresses Hcrt neuronal activity at the cellular level, and modulates stress responses, especially SIA and anxiety-related behavior in the whole organism. N/OFQ exerts its attenuation of SIA and anxiolytic action on fear-induced anxiety through direct modulation of Hcrt neuronal activity. The information obtained from these studies has provided insights into how interaction between the Hcrt and N/OFQ systems positively and negatively modulates the complex and integrated stress responses.
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Affiliation(s)
- Xinmin Simon Xie
- AfaSci Research Laboratories, Redwood City, California, USA; Department of Anesthesia, Stanford University School of Medicine, Stanford, California, USA.
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The energy allocation function of sleep: A unifying theory of sleep, torpor, and continuous wakefulness. Neurosci Biobehav Rev 2014; 47:122-53. [DOI: 10.1016/j.neubiorev.2014.08.001] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/27/2014] [Accepted: 08/02/2014] [Indexed: 12/14/2022]
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38
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Roles of orexins in the regulation of body weight homeostasis. Obes Res Clin Pract 2014; 8:e414-20. [DOI: 10.1016/j.orcp.2013.12.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 12/03/2013] [Indexed: 11/20/2022]
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Kukkonen JP, Leonard CS. Orexin/hypocretin receptor signalling cascades. Br J Pharmacol 2014; 171:314-31. [PMID: 23902572 DOI: 10.1111/bph.12324] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 07/18/2013] [Accepted: 07/28/2013] [Indexed: 12/16/2022] Open
Abstract
Orexin (hypocretin) peptides and their two known G-protein-coupled receptors play essential roles in sleep-wake control and powerfully influence other systems regulating appetite/metabolism, stress and reward. Consequently, drugs that influence signalling by these receptors may provide novel therapeutic opportunities for treating sleep disorders, obesity and addiction. It is therefore critical to understand how these receptors operate, the nature of the signalling cascades they engage and their physiological targets. In this review, we evaluate what is currently known about orexin receptor signalling cascades, while a sister review (Leonard & Kukkonen, this issue) focuses on tissue-specific responses. The evidence suggests that orexin receptor signalling is multifaceted and is substantially more diverse than originally thought. Indeed, orexin receptors are able to couple to members of at least three G-protein families and possibly other proteins, through which they regulate non-selective cation channels, phospholipases, adenylyl cyclase, and protein and lipid kinases. In the central nervous system, orexin receptors produce neuroexcitation by postsynaptic depolarization via activation of non-selective cation channels, inhibition of K⁺ channels and activation of Na⁺/Ca²⁺ exchange, but they also can stimulate the release of neurotransmitters by presynaptic actions and modulate synaptic plasticity. Ca²⁺ signalling is also prominently influenced by these receptors, both via the classical phospholipase C-Ca²⁺ release pathway and via Ca²⁺ influx, mediated by several pathways. Upon longer-lasting stimulation, plastic effects are observed in some cell types, while others, especially cancer cells, are stimulated to die. Thus, orexin receptor signals appear highly tunable, depending on the milieu in which they are operating.
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Affiliation(s)
- J P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
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40
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Gyires K, Zádori ZS. Brain neuropeptides in gastric mucosal protection. Curr Opin Pharmacol 2014; 19:24-30. [PMID: 24971914 DOI: 10.1016/j.coph.2014.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 05/29/2014] [Accepted: 06/01/2014] [Indexed: 01/15/2023]
Abstract
The centrally induced gastroprotective effect of neuropeptides has been intensively studied. Besides many similarities, however, differences can also be observed in their gastroprotective actions. The gastroprotective dose-response curve proved to be either sigmoid, or bell-shaped. Additional gastrointestinal effects of neuropeptides can contribute to their mucosal protective effect. Part of the neuropeptides induces gastroprotection by peripheral administration as well. Besides vagal nerve the sympathetic nervous system may also be involved in conveying the central effect to the periphery. Better understanding of the complex mechanism of the maintenance of gastric mucosal integrity may result in the development of new strategy to enhance gastric mucosal resistance against injury.
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Affiliation(s)
- Klára Gyires
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, 1089, Budapest, Hungary.
| | - Zoltán S Zádori
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, 1089, Budapest, Hungary
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Inutsuka A, Inui A, Tabuchi S, Tsunematsu T, Lazarus M, Yamanaka A. Concurrent and robust regulation of feeding behaviors and metabolism by orexin neurons. Neuropharmacology 2014; 85:451-60. [PMID: 24951857 DOI: 10.1016/j.neuropharm.2014.06.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/06/2014] [Accepted: 06/11/2014] [Indexed: 10/25/2022]
Abstract
Orexin neurons in the hypothalamus regulate energy homeostasis by coordinating various physiological responses. Past studies have shown the role of the orexin peptide itself; however, orexin neurons contain not only orexin but also other neurotransmitters such as glutamate and dynorphin. In this study, we examined the physiological role of orexin neurons in feeding behavior and metabolism by pharmacogenetic activation and chronic ablation. We generated novel orexin-Cre mice and utilized Cre-dependent adeno-associated virus vectors to express Gq-coupled modified GPCR, hM3Dq or diphtheria toxin fragment A in orexin neurons. By intraperitoneal injection of clozapine-N oxide in orexin-Cre mice expressing hM3Dq in orexin neurons, we could selectively manipulate the activity of orexin neurons. Pharmacogenetic stimulation of orexin neurons simultaneously increased locomotive activity, food intake, water intake and the respiratory exchange ratio (RER). Elevation of blood glucose levels and RER persisted even after locomotion and feeding behaviors returned to basal levels. Accordantly, 83% ablation of orexin neurons resulted in decreased food and water intake, while 70% ablation had almost no effect on these parameters. Our results indicate that orexin neurons play an integral role in regulation of both feeding behavior and metabolism. This regulation is so robust that greater than 80% of orexin neurons were ablated before significant changes in feeding behavior emerged.
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Affiliation(s)
- Ayumu Inutsuka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Azusa Inui
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Sawako Tabuchi
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Tomomi Tsunematsu
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Michael Lazarus
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba 305-8575, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
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42
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Penney CC, Volkoff H. Peripheral injections of cholecystokinin, apelin, ghrelin and orexin in cavefish (Astyanax fasciatus mexicanus): effects on feeding and on the brain expression levels of tyrosine hydroxylase, mechanistic target of rapamycin and appetite-related hormones. Gen Comp Endocrinol 2014; 196:34-40. [PMID: 24287340 DOI: 10.1016/j.ygcen.2013.11.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 12/27/2022]
Abstract
The effects of intraperitoneal injections of cholecystokinin (CCK), apelin, ghrelin, and orexin on food intake were examined in the blind cavefish Astyanax fasciatus mexicanus. CCK (50ng/g) induced a decrease in food intake whereas apelin (100ng/g), orexin (100ng/g), and ghrelin (100ng/g) induced an increase in food intake as compared to saline-injected control fish. In order to better understand the central mechanism by which these hormones act, we examined the effects of injections on the brain mRNA expression of two metabolic enzymes, tyrosine hydroxylase (TH), and mechanistic target of rapamycin (mTOR), and of appetite-regulating peptides, CCK, orexin, apelin and cocaine and amphetamine regulated transcript (CART). CCK injections induced a decrease in brain apelin injections, apelin injections induced an increase in TH, mTOR, and orexin brain expressions, orexin treatment increased brain TH expression and ghrelin injections induced an increase in mTOR and orexin brain expressions. CART expression was not affected by any of the injection treatments. Our results suggest that the enzymes TH and mTOR and the hormones CCK, apelin, orexin, and ghrelin all regulate food intake in cavefish through a complex network of interactions.
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Affiliation(s)
- Carla C Penney
- Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada
| | - Hélène Volkoff
- Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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Leonard CS, Kukkonen JP. Orexin/hypocretin receptor signalling: a functional perspective. Br J Pharmacol 2014; 171:294-313. [PMID: 23848055 PMCID: PMC3904253 DOI: 10.1111/bph.12296] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 06/17/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022] Open
Abstract
Multiple homeostatic systems are regulated by orexin (hypocretin) peptides and their two known GPCRs. Activation of orexin receptors promotes waking and is essential for expression of normal sleep and waking behaviour, with the sleep disorder narcolepsy resulting from the absence of orexin signalling. Orexin receptors also influence systems regulating appetite/metabolism, stress and reward, and are found in several peripheral tissues. Nevertheless, much remains unknown about the signalling pathways and targets engaged by native receptors. In this review, we integrate knowledge about the orexin receptor signalling capabilities obtained from studies in expression systems and various native cell types (as presented in Kukkonen and Leonard, this issue of British Journal of Pharmacology) with knowledge of orexin signalling in different tissues. The tissues reviewed include the CNS, the gastrointestinal tract, the pituitary gland, pancreas, adrenal gland, adipose tissue and the male reproductive system. We also summarize the findings in different native and recombinant cell lines, especially focusing on the different cascades in CHO cells, which is the most investigated cell line. This reveals that while a substantial gap exists between what is known about orexin receptor signalling and effectors in recombinant systems and native systems, mounting evidence suggests that orexin receptor signalling is more diverse than originally thought. Moreover, rather than being restricted to orexin receptor 'overexpressing' cells, this signalling diversity may be utilized by native receptors in a site-specific manner.
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Affiliation(s)
- C S Leonard
- Department of Physiology, New York Medical College, Valhalla, NY, USA
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44
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Saito YC, Tsujino N, Hasegawa E, Akashi K, Abe M, Mieda M, Sakimura K, Sakurai T. GABAergic neurons in the preoptic area send direct inhibitory projections to orexin neurons. Front Neural Circuits 2013; 7:192. [PMID: 24348342 PMCID: PMC3844858 DOI: 10.3389/fncir.2013.00192] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/13/2013] [Indexed: 11/13/2022] Open
Abstract
Populations of neurons in the hypothalamic preoptic area (POA) fire rapidly during sleep, exhibiting sleep/waking state-dependent firing patterns that are the reciprocal of those observed in the arousal system. The majority of these preoptic "sleep-active" neurons contain the inhibitory neurotransmitter GABA. On the other hand, a population of neurons in the lateral hypothalamic area (LHA) contains orexins, which play an important role in the maintenance of wakefulness, and exhibit an excitatory influence on arousal-related neurons. It is important to know the anatomical and functional interactions between the POA sleep-active neurons and orexin neurons, both of which play important, but opposite roles in regulation of sleep/wakefulness states. In this study, we confirmed that specific pharmacogenetic stimulation of GABAergic neurons in the POA leads to an increase in the amount of non-rapid eye movement (NREM) sleep. We next examined direct connectivity between POA GABAergic neurons and orexin neurons using channelrhodopsin 2 (ChR2) as an anterograde tracer as well as an optogenetic tool. We expressed ChR2-eYFP selectively in GABAergic neurons in the POA by AAV-mediated gene transfer, and examined the projection sites of ChR2-eYFP-expressing axons, and the effect of optogenetic stimulation of ChR2-eYFP on the activity of orexin neurons. We found that these neurons send widespread projections to wakefulness-related areas in the hypothalamus and brain stem, including the LHA where these fibers make close appositions to orexin neurons. Optogenetic stimulation of these fibers resulted in rapid inhibition of orexin neurons. These observations suggest direct connectivity between POA GABAergic neurons and orexin neurons.
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Affiliation(s)
- Yuki C Saito
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
| | - Natsuko Tsujino
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
| | - Emi Hasegawa
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
| | - Kaori Akashi
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Michihiro Mieda
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University Kanazawa, Japan
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45
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Cholecystokinin: an excitatory modulator of mitral/tufted cells in the mouse olfactory bulb. PLoS One 2013; 8:e64170. [PMID: 23691163 PMCID: PMC3655022 DOI: 10.1371/journal.pone.0064170] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 04/12/2013] [Indexed: 12/02/2022] Open
Abstract
Cholecystokinin (CCK) is widely distributed in the brain as a sulfated octapeptide (CCK-8S). In the olfactory bulb, CCK-8S is concentrated in two laminae: an infraglomerular band in the external plexiform layer, and an inframitral band in the internal plexiform layer (IPL), corresponding to somata and terminals of superficial tufted cells with intrabulbar projections linking duplicate glomerular maps of olfactory receptors. The physiological role of CCK in this circuit is unknown. We made patch clamp recordings of CCK effects on mitral cell spike activity in mouse olfactory bulb slices, and applied immunohistochemistry to localize CCKB receptors. In cell-attached recordings, mitral cells responded to 300 nM –1 µM CCK-8S by spike excitation, suppression, or mixed excitation-suppression. Antagonists of GABAA and ionotropic glutamate receptors blocked suppression, but excitation persisted. Whole-cell recordings revealed that excitation was mediated by a slow inward current, and suppression by spike inactivation or inhibitory synaptic input. Similar responses were elicited by the CCKB receptor-selective agonist CCK-4 (1 µM). Excitation was less frequent but still occurred when CCKB receptors were blocked by LY225910, or disrupted in CCKB knockout mice, and was also observed in CCKA knockouts. CCKB receptor immunoreactivity was detected on mitral and superficial tufted cells, colocalized with Tbx21, and was absent from granule cells and the IPL. Our data indicate that CCK excites mitral cells postsynaptically, via both CCKA and CCKB receptors. We hypothesize that extrasynaptic CCK released from tufted cell terminals in the IPL may diffuse to and directly excite mitral cell bodies, creating a positive feedback loop that can amplify output from pairs of glomeruli receiving sensory inputs encoded by the same olfactory receptor. Dynamic plasticity of intrabulbar projections suggests that this could be an experience-dependent amplification mechanism for tuning and optimizing olfactory bulb signal processing in different odor environments.
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46
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Furutani N, Hondo M, Kageyama H, Tsujino N, Mieda M, Yanagisawa M, Shioda S, Sakurai T. Neurotensin co-expressed in orexin-producing neurons in the lateral hypothalamus plays an important role in regulation of sleep/wakefulness states. PLoS One 2013; 8:e62391. [PMID: 23620827 PMCID: PMC3631195 DOI: 10.1371/journal.pone.0062391] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 03/24/2013] [Indexed: 02/03/2023] Open
Abstract
Both orexin and neurotensin are expressed in the lateral hypothalamic area (LHA) and have been implicated in the regulation of feeding, motor activity and the reward system. A double label immunofluorescence and in situ hybridization studies showed that neurotensin colocalizes with orexin in neurons of the LHA. Pharmacological studies suggested that neurotensin excites orexin-producing neurons (orexin neurons) through activation of neurotensin receptor-2 (NTSR-2) and non-selective cation channels. In situ hybridization study showed that most orexin neurons express neurotensin receptor-2 mRNA but not neurotensin receptor-1 (Ntsr-1) mRNA. Immunohistochemical studies showed that neurotensin-immunoreactive fibers make appositions to orexin neurons. A neurotensin receptor antagonist decreased Fos expression in orexin neurons and wakefulness time in wild type mice when administered intraperitoneally. However, the antagonist did not evoke any effect on these parameters in orexin neuron-ablated mice. These observations suggest the importance of neurotensin in maintaining activity of orexin neurons. The evidence presented here expands our understanding of the regulatory mechanism of orexin neurons.
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Affiliation(s)
- Naoki Furutani
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Mari Hondo
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
- Center for Behavioral Molecular Genetics, University of Tsukuba, Tsukuba, Japan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | - Haruaki Kageyama
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
| | - Natsuko Tsujino
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Michihiro Mieda
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Masashi Yanagisawa
- Center for Behavioral Molecular Genetics, University of Tsukuba, Tsukuba, Japan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Seiji Shioda
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
- * E-mail:
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47
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Tsujino N, Sakurai T. Role of orexin in modulating arousal, feeding, and motivation. Front Behav Neurosci 2013; 7:28. [PMID: 23616752 PMCID: PMC3629303 DOI: 10.3389/fnbeh.2013.00028] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 03/25/2013] [Indexed: 01/15/2023] Open
Abstract
Orexin deficiency results in narcolepsy in humans, dogs, and rodents, suggesting that the orexin system is particularly important for maintenance of wakefulness. However, orexin neurons are “multi-tasking” neurons that regulate sleep/wake states as well as feeding behavior, emotion, and reward processes. Orexin deficiency causes abnormalities in energy homeostasis, stress-related behavior, and reward systems. Orexin excites waking-active monoaminergic and cholinergic neurons in the hypothalamus and brain stem regions to maintain a long, consolidated waking period. Orexin neurons also have reciprocal links with the hypothalamic nuclei, which regulates feeding. Moreover, the responsiveness of orexin neurons to peripheral metabolic cues suggests that these neurons have an important role as a link between energy homeostasis and vigilance states. The link between orexin and the ventral tegmental nucleus serves to motivate an animal to engage in goal-directed behavior. This review focuses on the interaction of orexin neurons with emotion, reward, and energy homeostasis systems. These connectivities are likely to be highly important to maintain proper vigilance states.
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Affiliation(s)
- Natsuko Tsujino
- Department of Molecular Neuroscience and Integrative Physiology, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan
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48
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Sugawara Y, Echigo R, Kashima K, Minami H, Watanabe M, Nishikawa Y, Muranishi M, Yoneda M, Ohno-Shosaku T. Intracellular calcium level is an important factor influencing ion channel modulations by PLC-coupled metabotropic receptors in hippocampal neurons. Brain Res 2013; 1512:9-21. [PMID: 23548601 DOI: 10.1016/j.brainres.2013.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 10/27/2022]
Abstract
Signaling pathways involving phospholipase C (PLC) are involved in various neural functions. Understanding how these pathways are regulated will lead to a better understanding of their roles in neural functions. Previous studies demonstrated that receptor-driven PLCβ activation depends on intracellular Ca(2+) concentration ([Ca(2+)]i), suggesting the possibility that PLCβ-dependent cellular responses are basically Ca(2+) dependent. To test this possibility, we examined whether modulations of ion channels driven by PLC-coupled metabotropic receptors are sensitive to [Ca(2+)]i using cultured hippocampal neurons. Muscarinic activation triggered an inward current at -100 mV (the equilibrium potential for K(+)) in a subpopulation of neurons. This current response was suppressed by pirenzepine (an M1-preferring antagonist), PLC inhibitor, non-selective cation channel blocker, and lowering [Ca(2+)]i. Using the neurons showing no response at -100 mV, effects of muscarinic activation on K(+) channels were examined at -40 mV. Muscarinic activation induced a transient decrease of the holding outward current. This current response was mimicked and occluded by XE991, an M-current K(+) channel blocker, suppressed by pirenzepine, PLC inhibitor and lowering [Ca(2+)]i, and enhanced by elevating [Ca(2+)]i. Similar results were obtained when group I metabotropic glutamate receptors were activated instead of muscarinic receptors. These results clearly show that ion channel modulations driven by PLC-coupled metabotropic receptors are dependent on [Ca(2+)]i, supporting the hypothesis that cellular responses induced by receptor-driven PLCβ activation are basically Ca(2+) dependent.
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Affiliation(s)
- Yuto Sugawara
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
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49
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Translational profiling of hypocretin neurons identifies candidate molecules for sleep regulation. Genes Dev 2013; 27:565-78. [PMID: 23431030 DOI: 10.1101/gad.207654.112] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hypocretin (orexin; Hcrt)-containing neurons of the hypothalamus are essential for the normal regulation of sleep and wake behaviors and have been implicated in feeding, anxiety, depression, and reward. The absence of these neurons causes narcolepsy in humans and model organisms. However, little is known about the molecular phenotype of these cells; previous attempts at comprehensive profiling had only limited sensitivity or were inaccurate. We generated a Hcrt translating ribosome affinity purification (bacTRAP) line for comprehensive translational profiling of all ribosome-bound transcripts in these neurons in vivo. From this profile, we identified >6000 transcripts detectably expressed above background and 188 transcripts that are highly enriched in these neurons, including all known markers of the cells. Blinded analysis of in situ hybridization databases suggests that ~60% of these are expressed in a Hcrt marker-like pattern. Fifteen of these were confirmed with double labeling and microscopy, including the transcription factor Lhx9. Ablation of this gene results in a >30% loss specifically of Hcrt neurons, without a general disruption of hypothalamic development. Polysomnography and activity monitoring revealed a profound hypersomnolence in these mice. These data provide an in-depth and accurate profile of Hcrt neuron gene expression and suggest that Lhx9 may be important for specification or survival of a subset of these cells.
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Inutsuka A, Yamanaka A. The physiological role of orexin/hypocretin neurons in the regulation of sleep/wakefulness and neuroendocrine functions. Front Endocrinol (Lausanne) 2013; 4:18. [PMID: 23508038 PMCID: PMC3589707 DOI: 10.3389/fendo.2013.00018] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 02/12/2013] [Indexed: 11/28/2022] Open
Abstract
The hypothalamus monitors body homeostasis and regulates various behaviors such as feeding, thermogenesis, and sleeping. Orexins (also known as hypocretins) were identified as endogenous ligands for two orphan G-protein-coupled receptors in the lateral hypothalamic area. They were initially recognized as regulators of feeding behavior, but they are mainly regarded as key modulators of the sleep/wakefulness cycle. Orexins activate orexin neurons, monoaminergic and cholinergic neurons in the hypothalamus/brainstem regions, to maintain a long, consolidated awake period. Anatomical studies of neural projections from/to orexin neurons and phenotypic characterization of transgenic mice revealed various roles for orexin neurons in the coordination of emotion, energy homeostasis, reward system, and arousal. For example, orexin neurons are regulated by peripheral metabolic cues, including ghrelin, leptin, and glucose concentration. This suggests that they may provide a link between energy homeostasis and arousal states. A link between the limbic system and orexin neurons might be important for increasing vigilance during emotional stimuli. Orexins are also involved in reward systems and the mechanisms of drug addiction. These findings suggest that orexin neurons sense the outer and inner environment of the body and maintain the proper wakefulness level of animals for survival. This review discusses the mechanism by which orexins maintain sleep/wakefulness states and how this mechanism relates to other systems that regulate emotion, reward, and energy homeostasis.
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Affiliation(s)
| | - Akihiro Yamanaka
- *Correspondence: Akihiro Yamanaka, Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo, Chikusa, Nagoya 464-8601, Japan. e-mail:
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