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Chowdhury S, Hung CJ, Izawa S, Inutsuka A, Kawamura M, Kawashima T, Bito H, Imayoshi I, Abe M, Sakimura K, Yamanaka A. Dissociating orexin-dependent and -independent functions of orexin neurons using novel Orexin-Flp knock-in mice. eLife 2019; 8:44927. [PMID: 31159922 PMCID: PMC6548533 DOI: 10.7554/elife.44927] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022] Open
Abstract
Uninterrupted arousal is important for survival during threatening situations. Activation of orexin/hypocretin neurons is implicated in sustained arousal. However, orexin neurons produce and release orexin as well as several co-transmitters including dynorphin and glutamate. To disambiguate orexin-dependent and -independent physiological functions of orexin neurons, we generated a novel Orexin-flippase (Flp) knock-in mouse line. Crossing with Flp-reporter or Cre-expressing mice showed gene expression exclusively in orexin neurons. Histological studies confirmed that orexin was knock-out in homozygous mice. Orexin neurons without orexin showed altered electrophysiological properties, as well as received decreased glutamatergic inputs. Selective chemogenetic activation revealed that both orexin and co-transmitters functioned to increase wakefulness, however, orexin was indispensable to promote sustained arousal. Surprisingly, such activation increased the total time spent in cataplexy. Taken together, orexin is essential to maintain basic membrane properties and input-output computation of orexin neurons, as well as to exert awake-sustaining aptitude of orexin neurons.
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Affiliation(s)
- Srikanta Chowdhury
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Chi Jung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Shuntaro Izawa
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Ayumu Inutsuka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Meiko Kawamura
- Department of Animal Model development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Takashi Kawashima
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Itaru Imayoshi
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Manabu Abe
- Department of Animal Model development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kenji Sakimura
- Department of Animal Model development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
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52
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Cengiz M, Karaj V, Kocabasoğlu N, Gozubatik-Celik G, Dirican A, Bayoglu B. Orexin/hypocretin receptor, Orx1, gene variants are associated with major depressive disorder. Int J Psychiatry Clin Pract 2019; 23:114-121. [PMID: 30596528 DOI: 10.1080/13651501.2018.1551549] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Objective: Orexins (hypocretins) are neuropeptides expressed in hypothalamic neurons and have regulatory roles in feeding/drinking behaviours, endocrine functions and sleep/wakefulness state. Major depressive disorder (MDD) is a major mood disorder and neurotransmitter dysfunction in hypothalamic neurons may have roles in its formation. Hence, we conducted experiments to determine whether orexin receptor 1 and 2 (Orx1, Orx2) genes were associated with MDD development. Methods: Seventy-five MDD patients and 87 healthy controls were enrolled for the study. Genotyping was carried out with real-time polymerase chain reaction (RT-PCR). Hamilton Rating-Scale for Depression (HRSD) and Beck Depression Inventory (BDI) were utilized to evaluate depressive symptom severity. Results: A significant relation was found in genotype frequencies of Orx1 rs10914456 and rs2271933 variants between MDD patients and controls (p = .009, p = .006). Rs10914456 CC genotype increased MDD risk 3.57 times more than carrying other genotypes (p = .008, OR =3.57;95% CI: 1.39-9.14). However, no association was observed in Orx2 rs2653349 genotypes for MDD development (p > .05). Although statistically not significant, HRSD scores were diminished in MDD subjects carrying rs10914456 CC variants when compared with CT and TT variants (p = .069). Conclusion. This study suggests that, Orx1 rs10914456 and rs2271933 can be associated with MDD development. Hence, Orx1 rs10914456 variants may affect depressive symptom severity.
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Affiliation(s)
- Mujgan Cengiz
- a Department of Medical Biology, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Vilson Karaj
- b Department of Science, Institute of Forensic Sciences , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Nese Kocabasoğlu
- c Department of Psychiatry, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Gokcen Gozubatik-Celik
- d Department of Neurology, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
| | - Ahmet Dirican
- e Department of Biostatistics and Medical Informatics, Istanbul Medical Faculty , Istanbul University , Istanbul , Turkey
| | - Burcu Bayoglu
- a Department of Medical Biology, Cerrahpasa Medical Faculty , Istanbul University-Cerrahpasa , Istanbul , Turkey
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53
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Yamanashi T, Maki M, Kojima K, Shibukawa A, Tsukamoto T, Chowdhury S, Yamanaka A, Takagi S, Sudo Y. Quantitation of the neural silencing activity of anion channelrhodopsins in Caenorhabditis elegans and their applicability for long-term illumination. Sci Rep 2019; 9:7863. [PMID: 31133660 PMCID: PMC6536681 DOI: 10.1038/s41598-019-44308-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/14/2019] [Indexed: 11/15/2022] Open
Abstract
Ion pumps and channels are responsible for a wide variety of biological functions. Ion pumps transport only one ion during each stimulus-dependent reaction cycle, whereas ion channels conduct a large number of ions during each cycle. Ion pumping rhodopsins such as archaerhodopsin-3 (Arch) are often utilized as light-dependent neural silencers in animals, but they require a high-density light illumination of around 1 mW/mm2. Recently, anion channelrhodopsins -1 and -2 (GtACR1 and GtACR2) were discovered as light-gated anion channels from the cryptophyte algae Guillardia theta. GtACRs are therefore expected to silence neural activity much more efficiently than Arch. In this study, we successfully expressed GtACRs in neurons of the nematode Caenorhabditis elegans (C. elegans) and quantitatively evaluated how potently GtACRs can silence neurons in freely moving C. elegans. The results showed that the light intensity required for GtACRs to cause locomotion paralysis was around 1 µW/mm2, which is three orders of magnitude smaller than the light intensity required for Arch. As attractive features, GtACRs are less harmfulness to worms and allow stable neural silencing effects under long-term illumination. Our findings thus demonstrate that GtACRs possess a hypersensitive neural silencing activity in C. elegans and are promising tools for long-term neural silencing.
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Affiliation(s)
- Taro Yamanashi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Misayo Maki
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Keiichi Kojima
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Atsushi Shibukawa
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Takashi Tsukamoto
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.,Faculty of Advanced Life Science and Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo, 060-0810, Japan
| | - Srikanta Chowdhury
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
| | - Shin Takagi
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Yuki Sudo
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
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54
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Thomasy HE, Opp MR. Hypocretin Mediates Sleep and Wake Disturbances in a Mouse Model of Traumatic Brain Injury. J Neurotrauma 2019; 36:802-814. [PMID: 30136622 PMCID: PMC6387567 DOI: 10.1089/neu.2018.5810] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Traumatic brain injury (TBI) is a major cause of disability worldwide. Post-TBI sleep and wake disturbances are extremely common and difficult for patients to manage. Sleep and wake disturbances contribute to poor functional and emotional outcomes from TBI, yet effective therapies remain elusive. A more comprehensive understanding of mechanisms underlying post-TBI sleep and wake disturbance will facilitate development of effective pharmacotherapies. Previous research in human patients and animal models indicates that altered hypocretinergic function may be a major contributor to sleep-wake disturbance after TBI. In this study, we further elucidate the role of hypocretin by determining the impact of TBI on sleep-wake behavior of hypocretin knockout (HCRT KO) mice. Adult male C57BL/6J and HCRT KO mice were implanted with electroencephalography recording electrodes, and pre-injury baseline recordings were obtained. Mice were then subjected to either moderate TBI or sham surgery. Additional recordings were obtained and sleep-wake behavior determined at 3, 7, 15, and 30 days after TBI or sham procedures. At baseline, HCRT KO mice had a significantly different sleep-wake phenotype than control C57BL/6J mice. Post-TBI sleep-wake behavior was altered in a genotype-dependent manner: sleep of HCRT KO mice was not altered by TBI, whereas C57BL/6J mice had more non-rapid eye movement sleep, less wakefulness, and more short wake bouts and fewer long wake bouts. Numbers of hypocretin-positive cells were reduced in C57BL/6J mice by TBI. Collectively, these data indicate that the hypocretinergic system is involved in the alterations in sleep-wake behavior that develop after TBI in this model, and suggest potential therapeutic interventions.
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Affiliation(s)
- Hannah E. Thomasy
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington
| | - Mark R. Opp
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington
- Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, Washington
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55
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Iyer M, Essner RA, Klingenberg B, Carter ME. Identification of discrete, intermingled hypocretin neuronal populations. J Comp Neurol 2018; 526:2937-2954. [PMID: 30019757 DOI: 10.1002/cne.24490] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 06/12/2018] [Accepted: 06/14/2018] [Indexed: 01/04/2023]
Abstract
Neurons in the lateral hypothalamic area that express hypocretin (Hcrt) neuropeptides help regulate many behaviors including wakefulness and reward seeking. These neurons project throughout the brain, including to neural populations that regulate wakefulness, such as the locus coeruleus (LC) and tuberomammilary nucleus (TMN), as well as to populations that regulate reward, such as the nucleus accumbens (NAc) and ventral tegmental area (VTA). To address the roles of Hcrt neurons in seemingly disparate behaviors, it has been proposed that Hcrt neurons can be anatomically subdivided into at least two distinct subpopulations: a "medial group" that projects to the LC and TMN, and a "lateral group" that projects to the NAc and VTA. Here, we use a dual retrograde tracer strategy to test the hypotheses that Hcrt neurons can be classified based on their downstream projections and medial/lateral location within the hypothalamus. We found that individual Hcrt neurons were significantly more likely to project to both the LC and TMN or to both the VTA and NAc than would be predicted by chance. In contrast, we found that Hcrt neurons that projected to the LC or TMN were mostly distinct from Hcrt neurons that projected to the VTA or NAc. Interestingly, these two populations of Hcrt neurons are intermingled within the hypothalamus and cannot be classified into medial or lateral groups. These results suggest that Hcrt neurons can be distinguished based on their downstream projections but are intermingled within the hypothalamus.
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Affiliation(s)
- Manasi Iyer
- Department of Biology, Williams College, Williamstown, Massachusetts.,Program in Neuroscience, Williams College, Williamstown, Massachusetts
| | - Rachel A Essner
- Department of Biology, Williams College, Williamstown, Massachusetts.,Program in Neuroscience, Williams College, Williamstown, Massachusetts
| | - Bernhard Klingenberg
- Department of Mathematics and Statistics, Williams College, Williamstown, Massachusetts
| | - Matthew E Carter
- Department of Biology, Williams College, Williamstown, Massachusetts.,Program in Neuroscience, Williams College, Williamstown, Massachusetts
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56
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Han SY, Clarkson J, Piet R, Herbison AE. Optical Approaches for Interrogating Neural Circuits Controlling Hormone Secretion. Endocrinology 2018; 159:3822-3833. [PMID: 30304401 DOI: 10.1210/en.2018-00594] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/03/2018] [Indexed: 11/19/2022]
Abstract
Developments in optical imaging and optogenetics are transforming the functional investigation of neuronal networks throughout the brain. Recent studies in the neuroendocrine field have used genetic mouse models combined with a variety of light-activated optical tools as well as GCaMP calcium imaging to interrogate the neural circuitry controlling hormone secretion. The present review highlights the benefits and caveats of these approaches for undertaking both acute brain slice and functional studies in vivo. We focus on the use of channelrhodopsin and the inhibitory optogenetic tools, archaerhodopsin and halorhodopsin, in addition to GCaMP imaging of individual cells in vitro and neural populations in vivo using fiber photometry. We also address issues around the use of genetic vs viral delivery of encoded proteins to specific Cre-expressing cell populations, their quantification, and the use of conscious vs anesthetized animal models. To date, optogenetics and GCaMP imaging have proven useful in dissecting functional circuitry within the brain and are likely to become essential investigative tools for deciphering the different neural networks controlling hormone secretion.
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Affiliation(s)
- Su Young Han
- Centre for Neuroendocrinology and Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Jenny Clarkson
- Centre for Neuroendocrinology and Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Richard Piet
- Centre for Neuroendocrinology and Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Allan E Herbison
- Centre for Neuroendocrinology and Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
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57
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Latifi B, Adamantidis A, Bassetti C, Schmidt MH. Sleep-Wake Cycling and Energy Conservation: Role of Hypocretin and the Lateral Hypothalamus in Dynamic State-Dependent Resource Optimization. Front Neurol 2018; 9:790. [PMID: 30344503 PMCID: PMC6183196 DOI: 10.3389/fneur.2018.00790] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/31/2018] [Indexed: 12/23/2022] Open
Abstract
The hypocretin (Hcrt) system has been implicated in a wide range of physiological functions from sleep-wake regulation to cardiovascular, behavioral, metabolic, and thermoregulagtory control. These wide-ranging physiological effects have challenged the identification of a parsimonious function for Hcrt. A compelling hypothesis suggests that Hcrt plays a role in the integration of sleep-wake neurophysiology with energy metabolism. For example, Hcrt neurons promote waking and feeding, but are also sensors of energy balance. Loss of Hcrt function leads to an increase in REM sleep propensity, but a potential role for Hcrt linking energy balance with REM sleep expression has not been addressed. Here we examine a potential role for Hcrt and the lateral hypothalamus (LH) in state-dependent resource allocation as a means of optimizing resource utilization and, as a result, energy conservation. We review the energy allocation hypothesis of sleep and how state-dependent metabolic partitioning may contribute toward energy conservation, but with additional examination of how the loss of thermoregulatory function during REM sleep may impact resource optimization. Optimization of energy expenditures at the whole organism level necessitates a top-down network responsible for coordinating metabolic operations in a state-dependent manner across organ systems. In this context, we then specifically examine the potential role of the LH in regulating this output control, including the contribution from both Hcrt and melanin concentrating hormone (MCH) neurons among a diverse LH cell population. We propose that this hypothalamic integration system is responsible for global shifts in state-dependent resource allocations, ultimately promoting resource optimization and an energy conservation function of sleep-wake cycling.
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Affiliation(s)
- Blerina Latifi
- Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Antoine Adamantidis
- Department of Neurology, Center for Experimental Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department of Biomedical Research, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Claudio Bassetti
- Department of Neurology, Center for Experimental Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Markus H Schmidt
- Department of Neurology, Center for Experimental Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Ohio Sleep Medicine Institute, Dublin, OH, United States
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58
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Sargin D. The role of the orexin system in stress response. Neuropharmacology 2018; 154:68-78. [PMID: 30266600 DOI: 10.1016/j.neuropharm.2018.09.034] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/18/2018] [Accepted: 09/21/2018] [Indexed: 11/30/2022]
Abstract
Orexins are neuropeptides that are exclusively produced by hypothalamic neurons, which project throughout the entire brain. Orexin, also known as hypocretins, were initially identified to play a fundamental role in food intake, arousal and the regulation of sleep and wakefulness. Recent studies identified orexins to be critical for diverse physiological processes including motivation, reward, attention, emotional regulation, stress and anxiety. Here, I review recent findings that indicate orexin has an important role in acute and chronic stress. I also summarize the recent optogenetic and chemogenetic studies that have advanced our understanding of the orexin system. I will conclude by discussing clinical studies that implicate orexins in mental health disorders. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Derya Sargin
- Hotchkiss Brain Institute and the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
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59
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Sharma R, Sahota P, Thakkar MM. Melatonin promotes sleep in mice by inhibiting orexin neurons in the perifornical lateral hypothalamus. J Pineal Res 2018; 65:e12498. [PMID: 29654707 DOI: 10.1111/jpi.12498] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 03/27/2018] [Indexed: 12/14/2022]
Abstract
Melatonin promotes sleep. However, the underlying mechanisms are unknown. Orexin neurons in the perifornical lateral hypothalamus (PFH) are pivotal for wake promotion. Does melatonin promote sleep by inhibiting orexin neurons? We used C57BL/6J mice and designed 4 experiments to address this question. Experiment 1 used double-labeled immunofluorescence and examined the presence of melatonin receptors on orexin neurons. Second, mice, implanted with bilateral guides targeted toward PFH and sleep-recording electrodes, were infused with melatonin (500 pmole/50 nL/side) at dark onset (onset of active period), and spontaneous bouts of sleep-wakefulness were examined. Third, mice, implanted with bilateral guides into the PFH, were infused with melatonin (500 pmole/50 nL/side) at dark onset and euthanized 2 hours later, to examine the activation of orexin neurons using c-Fos expression in orexin neurons. Fourth, mice, implanted with PFH bilateral guides and sleep-recording electrodes, were infused with melatonin receptor antagonist, luzindole (10 pmol/50 nL/side), at light onset (onset of sleep period), and spontaneous bouts of sleep-wakefulness were examined. Our results suggest that orexin neurons express MT1, but not MT2 receptors. Melatonin infusion into the PFH, at dark onset, site-specifically and significantly increased NREM sleep (43.7%, P = .003) and reduced wakefulness (12.3%, P = .013). Local melatonin infusion at dark onset inhibited orexin neurons as evident by a significant reduction (66%, P = .0004) in the number of orexin neurons expressing c-Fos. Finally, luzindole infusion-induced blockade of melatonin receptors in PFH at sleep onset significantly increased wakefulness (44.1%, P = .015). Based on these results, we suggest that melatonin may act via the MT1 receptors to inhibit orexin neurons and promote sleep.
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Affiliation(s)
- Rishi Sharma
- Harry S. Truman Memorial Veterans Hospital and Department of Neurology, University of Missouri-School of Medicine, Columbia, MO, USA
| | - Pradeep Sahota
- Harry S. Truman Memorial Veterans Hospital and Department of Neurology, University of Missouri-School of Medicine, Columbia, MO, USA
| | - Mahesh M Thakkar
- Harry S. Truman Memorial Veterans Hospital and Department of Neurology, University of Missouri-School of Medicine, Columbia, MO, USA
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60
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Tanaka S, Okusa MD. Optogenetics in Understanding Mechanisms of Acute Kidney Injury. Nephron Clin Pract 2018; 140:152-155. [PMID: 29990991 DOI: 10.1159/000491498] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 06/24/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND No approved pharmacological agents are available for the treatment and prevention of acute kidney injury (AKI). The nervous system has been reported to play an important role, directly or indirectly via the immune system, in the pathophysiology of AKI. Neuromodulation, such as vagus nerve stimulation and pulsed ultrasound, is emerging as an innovative therapeutic treatment for various diseases including AKI. However, lack of effective methods to selectively stimulate or inhibit neurons has hampered the complete understanding of the roles of the nervous system in AKI because electrical stimulation is nonspecific for cell types. SUMMARY A novel technique called optogenetics optically controls cells in living tissues, typically neurons, which have been genetically modified to express light-sensitive opsins. For example, channelrhodopsin-2 (ChR2), an opsin, is a nonselective cation channel residing in a cell membrane, which rapidly opens its gate after exposing to monochromatic light in the "blue" wavelength. Unlike electrodes, blue light can selectively depolarize ChR2-expressing neurons, mainly via the Na+ entry, evoking an action potential. Optogenetics that use ChR2 and several variants to modulate kinetic properties and inhibitory opsins help in understanding the roles of the nervous system in AKI, thus leading to a clinical application of neuromodulation to AKI treatment.
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61
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62
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Adamantidis A, Lüthi A. Optogenetic Dissection of Sleep-Wake States In Vitro and In Vivo. Handb Exp Pharmacol 2018; 253:125-151. [PMID: 29687163 DOI: 10.1007/164_2018_94] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Optogenetic tools have revolutionized insights into the fundamentals of brain function. This is particularly true for our current understanding of sleep-wake regulation and sleep rhythms. This is illustrated here through a comprehensive and step-by-step review over the major brain areas involved in transitions between sleep and wake states and in sleep rhythmogenesis.
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Affiliation(s)
- Antoine Adamantidis
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland. .,Department of Clinical Research (DKF), University of Bern, Bern, Switzerland.
| | - Anita Lüthi
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
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63
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Akladious A, Azzam S, Hu Y, Feng P. Bmal1 knockdown suppresses wake and increases immobility without altering orexin A, corticotrophin-releasing hormone, or glutamate decarboxylase. CNS Neurosci Ther 2018; 24:549-563. [PMID: 29446232 DOI: 10.1111/cns.12815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 01/02/2018] [Accepted: 01/10/2018] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To determine the effect of Bmal1 knockdown (KD) on sleep, activity, immobility, hypothalamic levels of orexin, corticotrophin-releasing hormone (CRH), and GABAergic glutamate decarboxylase (GAD). METHODS We used Bmal1 siRNA, or control siRNA intracerebroventricular (ICV) injection to knock down Bmal1 in C57BL/6 mice. Sleep polysomnography, wheel-running activity, and tail suspension test were performed. Polysomnographic (PSG) recordings in both groups were preceded by ICV injection made during both the light phase and the dark phase. We also measured brain orexin A and CRH using an ELISA and measured GAD using immunoblotting. RESULTS Compared with control group, Bmal1 KD group had reduced wheel activity and increased immobility. Compared with control, the Bmal1 KD group had reduced wheel activity and increased immobility. During the first 24 hours after treatment, we observed that control siRNA induced a much greater increase in sleep during the dark phase, which was associated with lower orexin levels. However, beginning 24 hours after treatment, we observed an increase in sleep and a decrease in time spent awake during the dark phase in the Bmal1 KD group. These changes were not associated with changes in brain levels of orexin A, CRH, or GAD. CONCLUSION Bmal1 KD led to reduced activity, increased immobility, and dramatic reduction in time spent awake as well as an increase in sleep during the dark phase. Early after injection, there was a slight change in sleep but brain levels of orexin, CRH, and GAD remain unchanged. Control siRNA also affected sleep associated with changes in orexin levels.
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Affiliation(s)
- Afaf Akladious
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Sausan Azzam
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Yufen Hu
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Pingfu Feng
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA
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64
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Tarasiuk A, Segev Y. Abnormal Growth and Feeding Behavior in Upper Airway Obstruction in Rats. Front Endocrinol (Lausanne) 2018; 9:298. [PMID: 29915561 PMCID: PMC5994397 DOI: 10.3389/fendo.2018.00298] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/18/2018] [Indexed: 12/18/2022] Open
Abstract
Pediatric obstructive sleep apnea (OSA) is a syndrome manifesting with snoring and increased respiratory effort due to increased upper airway resistance. In addition to cause the abnormal sleep, this syndrome has been shown to elicit either growth retardation or metabolic syndrome and obesity. Treating OSA by adenotonsillectomy is usually associated with increased risk for obesity, despite near complete restoration of breathing and sleep. However, the underlying mechanism linking upper airways obstruction (AO) to persistent change in food intake, metabolism, and growth remains unclear. Rodent models have examined the impact of intermittent hypoxia on metabolism. However, an additional defining feature of OSA that is not related to intermittent hypoxia is enhanced respiratory loading leading to increased respiratory effort and abnormal sleep. The focus of this mini review is on recent evidence indicating the persistent abnormalities in endocrine regulation of feeding and growth that are not fully restored by the chronic upper AO removal in rats. Here, we highlight important aspects related to abnormal regulation of metabolism that are not related to intermittent hypoxia per se, in an animal model that mimics many of the clinical features of pediatric OSA. Our evidence from the AO model indicates that obstruction removal may not be sufficient to prevent the post-removal tendency for abnormal growth.
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Affiliation(s)
- Ariel Tarasiuk
- Sleep-Wake Disorders Unit, Soroka University Medical Center, Beer-Sheva, Israel
- Department of Physiology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- *Correspondence: Ariel Tarasiuk,
| | - Yael Segev
- Shraga Segal Department of Microbiology and Immunology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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65
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Shiromani PJ, Peever JH. New Neuroscience Tools That Are Identifying the Sleep-Wake Circuit. Sleep 2017; 40:3059391. [PMID: 28329204 DOI: 10.1093/sleep/zsx032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The complexity of the brain is yielding to technology. In the area of sleep neurobiology, conventional neuroscience tools such as lesions, cell recordings, c-Fos, and axon-tracing methodologies have been instrumental in identifying the complex and intermingled populations of sleep- and arousal-promoting neurons that orchestrate and generate wakefulness, NREM, and REM sleep. In the last decade, new technologies such as optogenetics, chemogenetics, and the CRISPR-Cas system have begun to transform how biologists understand the finer details associated with sleep-wake regulation. These additions to the neuroscience toolkit are helping to identify how discrete populations of brain cells function to trigger and shape the timing and transition into and out of different sleep-wake states, and how glia partner with neurons to regulate sleep. Here, we detail how some of the newest technologies are being applied to understand the neural circuits underlying sleep and wake.
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Affiliation(s)
- Priyattam J Shiromani
- Ralph H. Johnson Veterans Administration Medical Center, Research Service, Charleston, SC
| | - John H Peever
- Centre for Biological Timing and Cognition, Department Cell and Systems Biology, and Physiology, University of Toronto, Toronto, ON, Canada
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66
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Hypothalamic Tuberomammillary Nucleus Neurons: Electrophysiological Diversity and Essential Role in Arousal Stability. J Neurosci 2017; 37:9574-9592. [PMID: 28874450 DOI: 10.1523/jneurosci.0580-17.2017] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 08/10/2017] [Accepted: 08/19/2017] [Indexed: 11/21/2022] Open
Abstract
Histaminergic (HA) neurons, found in the posterior hypothalamic tuberomammillary nucleus (TMN), extend fibers throughout the brain and exert modulatory influence over numerous physiological systems. Multiple lines of evidence suggest that the activity of HA neurons is important in the regulation of vigilance despite the lack of direct, causal evidence demonstrating its requirement for the maintenance of arousal during wakefulness. Given the strong correlation between HA neuron excitability and behavioral arousal, we investigated both the electrophysiological diversity of HA neurons in brain slices and the effect of their acute silencing in vivo in male mice. For this purpose, we first validated a transgenic mouse line expressing cre recombinase in histidine decarboxylase-expressing neurons (Hdc-Cre) followed by a systematic census of the membrane properties of both HA and non-HA neurons in the ventral TMN (TMNv) region. Through unsupervised hierarchical cluster analysis, we found electrophysiological diversity both between TMNv HA and non-HA neurons, and among HA neurons. To directly determine the impact of acute cessation of HA neuron activity on sleep-wake states in awake and behaving mice, we examined the effects of optogenetic silencing of TMNv HA neurons in vivo We found that acute silencing of HA neurons during wakefulness promotes slow-wave sleep, but not rapid eye movement sleep, during a period of low sleep pressure. Together, these data suggest that the tonic firing of HA neurons is necessary for the maintenance of wakefulness, and their silencing not only impairs arousal but is sufficient to rapidly and selectively induce slow-wave sleep.SIGNIFICANCE STATEMENT The function of monoaminergic systems and circuits that regulate sleep and wakefulness is often disrupted as part of the pathophysiology of many neuropsychiatric disorders. One such circuit is the posterior hypothalamic histamine (HA) system, implicated in supporting wakefulness and higher brain function, but has been difficult to selectively manipulate owing to cellular heterogeneity in this region. Here we use a transgenic mouse to interrogate both the characteristic firing properties of HA neurons and their specific role in maintaining wakefulness. Our results demonstrate that the acute, cell type-specific silencing of HA neurons during wakefulness is sufficient to not only impair arousal but to rapidly and selectively induce slow-wave sleep. This work furthers our understanding of HA-mediated mechanisms that regulate behavioral arousal.
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67
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Abstract
The discovery of the orexin system represents the single major progress in the sleep field of the last three to four decades. The two orexin peptides and their two receptors play a major role in arousal and sleep/wake cycles. Defects in the orexin system lead to narcolepsy with cataplexy in humans and dogs and can be experimentally reproduced in rodents. At least six orexin receptor antagonists have reached Phase II or Phase III clinical trials in insomnia, five of which are dual orexin receptor antagonists (DORAs) that target both OX1 and OX2 receptors (OX2Rs). All clinically tested DORAs induce and maintain sleep: suvorexant, recently registered in the USA and Japan for insomnia, represents the first hypnotic principle that acts in a completely different manner from the current standard medications. It is clear, however, that in the clinic, all DORAs promote sleep primarily by increasing rapid eye movement (REM) and are almost devoid of effects on slow-wave (SWS) sleep. At present, there is no consensus on whether the sole promotion of REM sleep has a negative impact in patients suffering from insomnia. However, sleep onset REM (SOREM), which has been documented with DORAs, is clearly an undesirable effect, especially for narcoleptic patients and also in fragile populations (e.g. elderly patients) where REM-associated loss of muscle tone may promote an elevated risk of falls. Debate thus remains as to the ideal orexin agent to achieve a balanced increase in REM and non-rapid eye movement (NREM) sleep. Here, we review the evidence that an OX2R antagonist should be at least equivalent, or perhaps superior, to a DORA for the treatment of insomnia. An OX2R antagonist may produce more balanced sleep than a DORA. Rodent sleep experiments show that the OX2R is the primary target of orexin receptor antagonists in sleep modulation. Furthermore, an OX2R antagonist should, in theory, have a lower narcoleptic/cataplexic potential. In the clinic, the situation remains equivocal, since OX2R antagonists are in early stages: MK-1064 has completed Phase I, and MIN202 is currently in clinical Phase II/III trials. However, data from insomnia patients have not yet been released. Promotional material suggests that balanced sleep is indeed induced by MIN-202, whereas in volunteers MK-1064 has been reported to act similarly to DORAs.
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Affiliation(s)
- Laura H Jacobson
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Sui Chen
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Sanjida Mir
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Daniel Hoyer
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia.
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
- Department of Chemical Physiology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA.
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Connexin 43-Mediated Astroglial Metabolic Networks Contribute to the Regulation of the Sleep-Wake Cycle. Neuron 2017; 95:1365-1380.e5. [PMID: 28867552 DOI: 10.1016/j.neuron.2017.08.022] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 06/29/2017] [Accepted: 08/14/2017] [Indexed: 01/13/2023]
Abstract
Astrocytes produce and supply metabolic substrates to neurons through gap junction-mediated astroglial networks. However, the role of astroglial metabolic networks in behavior is unclear. Here, we demonstrate that perturbation of astroglial networks impairs the sleep-wake cycle. Using a conditional Cre-Lox system in mice, we show that knockout of the gap junction subunit connexin 43 in astrocytes throughout the brain causes excessive sleepiness and fragmented wakefulness during the nocturnal active phase. This astrocyte-specific genetic manipulation silenced the wake-promoting orexin neurons located in the lateral hypothalamic area (LHA) by impairing glucose and lactate trafficking through astrocytic networks. This global wakefulness instability was mimicked with viral delivery of Cre recombinase to astrocytes in the LHA and rescued by in vivo injections of lactate. Our findings propose a novel regulatory mechanism critical for maintaining normal daily cycle of wakefulness and involving astrocyte-neuron metabolic interactions.
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69
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Optogenetic Investigation of Arousal Circuits. Int J Mol Sci 2017; 18:ijms18081773. [PMID: 28809797 PMCID: PMC5578162 DOI: 10.3390/ijms18081773] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/06/2017] [Accepted: 08/09/2017] [Indexed: 12/13/2022] Open
Abstract
Modulation between sleep and wake states is controlled by a number of heterogeneous neuron populations. Due to the topological proximity and genetic co-localization of the neurons underlying sleep-wake state modulation optogenetic methods offer a significant improvement in the ability to benefit from both the precision of genetic targeting and millisecond temporal control. Beginning with an overview of the neuron populations mediating arousal, this review outlines the progress that has been made in the investigation of arousal circuits since the incorporation of optogenetic techniques and the first in vivo application of optogenetic stimulation in hypocretin neurons in the lateral hypothalamus. This overview is followed by a discussion of the future progress that can be made by incorporating more recent technological developments into the research of neural circuits.
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70
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Ogawa Y, Kanda T, Vogt K, Yanagisawa M. Anatomical and electrophysiological development of the hypothalamic orexin neurons from embryos to neonates. J Comp Neurol 2017; 525:3809-3820. [PMID: 28608460 DOI: 10.1002/cne.24261] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 04/19/2017] [Accepted: 04/19/2017] [Indexed: 02/01/2023]
Abstract
The amount, quality, and diurnal pattern of sleep change greatly during development. Developmental changes of sleep/wake architecture are in a close relationship to brain development. The fragmentation of wake episodes is one of the salient features in the neonatal period, which is also observed in mature animals and human individuals lacking neuropeptide orexin/hypocretin signaling. This raises the possibility that developmental changes of lateral hypothalamic orexin neurons are relevant to the development of sleep/wake architecture. However, little information is available on morphological and physiological features of developing orexin neurons. To address the cellular basis for maturation of the sleep/wake regulatory system, we investigated the functional development of orexin neurons in the lateral hypothalamus. The anatomical development as well as the changes in the electrophysiological characteristics of orexin neurons was examined from embryonic to postnatal stages in orexin-EGFP mice. Prepro-orexin promoter activity was detectable at embryonic day (E) 12.0, followed by expression of orexin A after E14.0. The number of orexin neurons and their membrane capacitance reached similar levels to adults by postnatal day (P) 7, while their membrane potentials, firing rates, and action potential waveforms were developed by P21. The hyperpolarizing effect of serotonin, which is a major inhibitory signal for adult orexin neurons, was detected after E18.0 and matured at P1. These results suggest that the expression of orexin peptides precedes the maturation of electrophysiological activity of orexin neurons. The function of orexin neurons gradually matures by 3 weeks after birth, coinciding with maturation of sleep/wake architecture.
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Affiliation(s)
- Yukino Ogawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takeshi Kanda
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kaspar Vogt
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan.,Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas
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71
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Zhang H, Cohen AE. Optogenetic Approaches to Drug Discovery in Neuroscience and Beyond. Trends Biotechnol 2017; 35:625-639. [PMID: 28552428 PMCID: PMC5495001 DOI: 10.1016/j.tibtech.2017.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/08/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022]
Abstract
Recent advances in optogenetics have opened new routes to drug discovery, particularly in neuroscience. Physiological cellular assays probe functional phenotypes that connect genomic data to patient health. Optogenetic tools, in particular tools for all-optical electrophysiology, now provide a means to probe cellular disease models with unprecedented throughput and information content. These techniques promise to identify functional phenotypes associated with disease states and to identify compounds that improve cellular function regardless of whether the compound acts directly on a target or through a bypass mechanism. This review discusses opportunities and unresolved challenges in applying optogenetic techniques throughout the discovery pipeline - from target identification and validation, to target-based and phenotypic screens, to clinical trials.
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Affiliation(s)
- Hongkang Zhang
- Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Adam E Cohen
- Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Department of Physics, Harvard University, Cambridge, MA 02138, USA.
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72
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Ferreira JGP, Bittencourt JC, Adamantidis A. Melanin-concentrating hormone and sleep. Curr Opin Neurobiol 2017; 44:152-158. [DOI: 10.1016/j.conb.2017.04.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/31/2017] [Accepted: 04/11/2017] [Indexed: 01/11/2023]
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73
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Pintwala S, Peever J. Circuit mechanisms of sleepiness and cataplexy in narcolepsy. Curr Opin Neurobiol 2017; 44:50-58. [DOI: 10.1016/j.conb.2017.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/07/2017] [Indexed: 12/23/2022]
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74
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Equihua-Benítez AC, Guzmán-Vásquez K, Drucker-Colín R. Understanding sleep-wake mechanisms and drug discovery. Expert Opin Drug Discov 2017; 12:643-657. [PMID: 28511597 DOI: 10.1080/17460441.2017.1329818] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Although not discernible at first glance, sleep is a highly active and regulated brain state. Although we spend practically one third of our lifetimes in this stage, its importance is often taken for granted. Sleep loss can lead to disease, error and economic loss. Our understanding of how sleep is achieved has greatly advanced in recent years, and with that, the management of sleep disorders has improved. There is still room for improvement and recently many new compounds have reached clinical trials with a few being approved for commercial use. Areas covered: In this review, the authors make the case of sleep disorders as a matter of public health. The mechanisms of sleep transition are discussed emphasizing the wake and sleep promoting interaction of different brain regions. Finally, advances in pharmacotherapy are examined in the context of chronic insomnia and narcolepsy. Expert opinion: The orexinergic system is an example of a breakthrough in sleep medicine that has catalyzed drug development. Nevertheless, sleep is a topic still with many unanswered questions. That being said, the melanin-concentrating hormone system is becoming increasingly relevant and we speculate it will be the next target of sleep medication.
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Affiliation(s)
- Ana Clementina Equihua-Benítez
- a Departamento de Neuropatología Molecular , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Ciudad de México , México
| | - Khalil Guzmán-Vásquez
- a Departamento de Neuropatología Molecular , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Ciudad de México , México
| | - René Drucker-Colín
- a Departamento de Neuropatología Molecular , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Ciudad de México , México
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75
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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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76
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Eban-Rothschild A, Giardino WJ, de Lecea L. To sleep or not to sleep: neuronal and ecological insights. Curr Opin Neurobiol 2017; 44:132-138. [PMID: 28500869 DOI: 10.1016/j.conb.2017.04.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/07/2017] [Accepted: 04/20/2017] [Indexed: 12/13/2022]
Abstract
Daily, animals need to decide when to stop engaging in cognitive processes and behavioral responses to the environment, and go to sleep. The main processes regulating the daily organization of sleep and wakefulness are circadian rhythms and homeostatic sleep pressure. In addition, motivational processes such as food seeking and predator evasion can modulate sleep/wake behaviors. Here, we discuss the principal processes regulating the propensity to stay awake or go to sleep-focusing on neuronal and behavioral aspects. We first introduce the neuronal populations involved in sleep/wake regulation. Next, we describe the circadian and homeostatic drives for sleep. Then, we highlight studies demonstrating various effects of motivational processes on sleep/wake behaviors, and discuss possible neuronal mechanisms underlying their control.
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Affiliation(s)
- Ada Eban-Rothschild
- Department of Psychiatry and Behavioral Sciences, Stanford University, 1201 Welch Road, Stanford, CA 94305, USA.
| | - William J Giardino
- Department of Psychiatry and Behavioral Sciences, Stanford University, 1201 Welch Road, Stanford, CA 94305, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University, 1201 Welch Road, Stanford, CA 94305, USA.
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77
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Mieda M. The roles of orexins in sleep/wake regulation. Neurosci Res 2017; 118:56-65. [DOI: 10.1016/j.neures.2017.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 10/25/2022]
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78
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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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79
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Abstract
Narcolepsy is a chronic sleep disorder that has a typical onset in adolescence and is characterized by excessive daytime sleepiness, which can have severe consequences for the patient. Problems faced by patients with narcolepsy include social stigma associated with this disease, difficulties in obtaining an education and keeping a job, a reduced quality of life and socioeconomic consequences. Two subtypes of narcolepsy have been described (narcolepsy type 1 and narcolepsy type 2), both of which have similar clinical profiles, except for the presence of cataplexy, which occurs only in patients with narcolepsy type 1. The pathogenesis of narcolepsy type 1 is hypothesized to be the autoimmune destruction of the hypocretin-producing neurons in the hypothalamus; this hypothesis is supported by immune-related genetic and environmental factors associated with the disease. However, direct evidence in support of the autoimmune hypothesis is currently unavailable. Diagnosis of narcolepsy encompasses clinical, electrophysiological and biological evaluations, but simpler and faster procedures are needed. Several medications are available for the symptomatic treatment of narcolepsy, all of which have quite good efficacy and safety profiles. However, to date, no treatment hinders or slows disease development. Improved diagnostic tools and increased understanding of the pathogenesis of narcolepsy type 1 are needed and might lead to therapeutic or even preventative interventions.
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Affiliation(s)
- Birgitte R Kornum
- Molecular Sleep Laboratory, Department of Clinical Biochemistry, Rigshospitalet, Forskerparken, Nordre Ringvej 69, 2600 Glostrup, Denmark.,Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Stine Knudsen
- Norwegian Centre of Expertise for Neurodevelopmental Disorders and Hypersomnias, Oslo University Hospital, Oslo, Norway
| | - Hanna M Ollila
- Department of Psychiatry and Behavioral Sciences, Center for Sleep Sciences, Stanford University, Stanford, California, USA
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, AUSL di Bologna, Bologna, Italy
| | - Poul J Jennum
- Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Yves Dauvilliers
- Sleep Unit, Narcolepsy Reference Center, Department of Neurology, Gui de Chauliac Hospital, INSERM 1061, Montpellier, France
| | - Sebastiaan Overeem
- Sleep Medicine Center Kempenhaeghe, Heeze, The Netherlands.,Department of Industrial Design, Eindhoven University of Technology, Eindhoven, The Netherlands
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80
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James MH, Mahler SV, Moorman DE, Aston-Jones G. A Decade of Orexin/Hypocretin and Addiction: Where Are We Now? Curr Top Behav Neurosci 2017; 33:247-281. [PMID: 28012090 PMCID: PMC5799809 DOI: 10.1007/7854_2016_57] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
One decade ago, our laboratory provided the first direct evidence linking orexin/hypocretin signaling with drug seeking by showing that activation of these neurons promotes conditioned morphine-seeking behavior. In the years since, contributions from many investigators have revealed roles for orexins in addiction for all drugs of abuse tested, but only under select circumstances. We recently proposed that orexins play a fundamentally unified role in coordinating "motivational activation" under numerous behavioral conditions, and here we unpack this hypothesis as it applies to drug addiction. We describe evidence collected over the past 10 years that elaborates the role of orexin in drug seeking under circumstances where high levels of effort are required to obtain the drug, or when motivation for drug reward is augmented by the presence of external stimuli like drug-associated cues/contexts or stressors. Evidence from studies using traditional self-administration and reinstatement models, as well as behavioral economic analyses of drug demand elasticity, clearly delineates a role for orexin in modulating motivational, rather than the primary reinforcing aspects of drug reward. We also discuss the anatomical interconnectedness of the orexin system with wider motivation and reward circuits, with a particular focus on how orexin modulates prefrontal and other glutamatergic inputs onto ventral tegmental area dopamine neurons. Last, we look ahead to the next decade of the research in this area, highlighting the recent FDA approval of the dual orexin receptor antagonist suvorexant (Belsomra®) for the treatment of insomnia as a promising sign of the potential clinical utility of orexin-based therapies for the treatment of addiction.
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Affiliation(s)
- Morgan H James
- Brain Health Institute, Rutgers University/Rutgers Biomedical and Health Sciences, Piscataway, NJ, 08854, USA
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 2337, Australia
| | - Stephen V Mahler
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, 92967, USA
| | - David E Moorman
- Department of Psychological and Brain Sciences & Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Gary Aston-Jones
- Brain Health Institute, Rutgers University/Rutgers Biomedical and Health Sciences, Piscataway, NJ, 08854, USA.
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81
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Abstract
Optogenetic methods have been highly effective for suppressing neural activity and modulating behavior in rodents, but effects have been much smaller in primates, which have much larger brains. Here, we present a suite of technologies to use optogenetics effectively in primates and apply these tools to a classic question in oculomotor control. First, we measured light absorption and heat propagation in vivo, optimized the conditions for using the red-light-shifted halorhodopsin Jaws in primates, and developed a large-volume illuminator to maximize light delivery with minimal heating and tissue displacement. Together, these advances allowed for nearly universal neuronal inactivation across more than 10 mm3 of the cortex. Using these tools, we demonstrated large behavioral changes (i.e., up to several fold increases in error rate) with relatively low light power densities (≤100 mW/mm2) in the frontal eye field (FEF). Pharmacological inactivation studies have shown that the FEF is critical for executing saccades to remembered locations. FEF neurons increase their firing rate during the three epochs of the memory-guided saccade task: visual stimulus presentation, the delay interval, and motor preparation. It is unclear from earlier work, however, whether FEF activity during each epoch is necessary for memory-guided saccade execution. By harnessing the temporal specificity of optogenetics, we found that FEF contributes to memory-guided eye movements during every epoch of the memory-guided saccade task (the visual, delay, and motor periods).
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82
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Blanco-Centurion C, Liu M, Konadhode RP, Zhang X, Pelluru D, van den Pol AN, Shiromani PJ. Optogenetic activation of melanin-concentrating hormone neurons increases non-rapid eye movement and rapid eye movement sleep during the night in rats. Eur J Neurosci 2016; 44:2846-2857. [PMID: 27657541 DOI: 10.1111/ejn.13410] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 09/15/2016] [Accepted: 09/19/2016] [Indexed: 01/06/2023]
Abstract
Neurons containing melanin-concentrating hormone (MCH) are located in the hypothalamus. In mice, optogenetic activation of the MCH neurons induces both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep at night, the normal wake-active period for nocturnal rodents [R. R. Konadhode et al. (2013) J. Neurosci., 33, 10257-10263]. Here we selectively activate these neurons in rats to test the validity of the sleep network hypothesis in another species. Channelrhodopsin-2 (ChR2) driven by the MCH promoter was selectively expressed by MCH neurons after injection of rAAV-MCHp-ChR2-EYFP into the hypothalamus of Long-Evans rats. An in vitro study confirmed that the optogenetic activation of MCH neurons faithfully triggered action potentials. In the second study, in Long-Evans rats, rAAV-MCH-ChR2, or the control vector, rAAV-MCH-EYFP, were delivered into the hypothalamus. Three weeks later, baseline sleep was recorded for 48 h without optogenetic stimulation (0 Hz). Subsequently, at the start of the lights-off cycle, the MCH neurons were stimulated at 5, 10, or 30 Hz (1 mW at tip; 1 min on - 4 min off) for 24 h. Sleep was recorded during the 24-h stimulation period. Optogenetic activation of MCH neurons increased both REM and NREM sleep at night, whereas during the day cycle, only REM sleep was increased. Delta power, an indicator of sleep intensity, was also increased. In control rats without ChR2, optogenetic stimulation did not increase sleep or delta power. These results lend further support to the view that sleep-active MCH neurons contribute to drive sleep in mammals.
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Affiliation(s)
- Carlos Blanco-Centurion
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 114 Doughty Street, MSC 404/STB 404, Charleston, SC, 29425, USA
| | - Meng Liu
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 114 Doughty Street, MSC 404/STB 404, Charleston, SC, 29425, USA
| | - Roda P Konadhode
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 114 Doughty Street, MSC 404/STB 404, Charleston, SC, 29425, USA
| | - Xiaobing Zhang
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Dheeraj Pelluru
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 114 Doughty Street, MSC 404/STB 404, Charleston, SC, 29425, USA
| | | | - Priyattam J Shiromani
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 114 Doughty Street, MSC 404/STB 404, Charleston, SC, 29425, USA.,Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC, USA
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83
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Govorunova EG, Koppel LA. The Road to Optogenetics: Microbial Rhodopsins. BIOCHEMISTRY (MOSCOW) 2016; 81:928-40. [PMID: 27682165 DOI: 10.1134/s0006297916090029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Optogenetics technology (using light-sensitive microbial proteins to control animal cell physiology) is becoming increasingly popular in laboratories around the world. Among these proteins, particularly important are rhodopsins that transport ions across the membrane and are used in optogenetics to regulate membrane potential by light, mostly in neurons. Although rhodopsin ion pumps transport only one charge per captured photon, channelrhodopsins are capable of more efficient passive transport. In this review, we follow the history of channelrhodopsin discovery in flagellate algae and discuss the latest addition to the channelrhodopsin family, channels with anion, rather than cation, selectivity.
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Affiliation(s)
- E G Govorunova
- Lomonosov Moscow State University, School of Biology, Moscow, 119991, Russia.
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84
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Calderon DP, Kilinc M, Maritan A, Banavar JR, Pfaff D. Generalized CNS arousal: An elementary force within the vertebrate nervous system. Neurosci Biobehav Rev 2016; 68:167-176. [PMID: 27216213 PMCID: PMC5003634 DOI: 10.1016/j.neubiorev.2016.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/19/2016] [Accepted: 05/19/2016] [Indexed: 01/13/2023]
Abstract
Why do animals and humans do anything at all? Arousal is the most powerful and essential function of the brain, a continuous function that accounts for the ability of animals and humans to respond to stimuli in the environment by producing muscular responses. Following decades of psychological, neurophysiological and molecular investigations, generalized CNS arousal can now be analyzed using approaches usually applied to physical systems. The concept of "criticality" is a state that illustrates an advantage for arousal systems poised near a phase transition. This property provides speed and sensitivity and facilitates the transition of the system into different brain states, especially as the brain crosses a phase transition from less aroused to more aroused states. In summary, concepts derived from applied mathematics of physical systems will now find their application in this area of neuroscience, the neurobiology of CNS arousal.
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Affiliation(s)
- D P Calderon
- Laboratory for Neurobiology and Behavior, the Rockefeller University, New York, NY 10065, United States; Department of Anaesthesiology, Weill Cornell Medical College, New York, NY 10021, United States.
| | - M Kilinc
- Laboratory for Neurobiology and Behavior, the Rockefeller University, New York, NY 10065, United States
| | - A Maritan
- Department of Physics, University of Padova, Istituto Nazionale di Fisica Nucleare and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, 35131 Padova, Italy
| | - J R Banavar
- Department of Physics, University of Maryland, College Park, MD 20742, United States
| | - D Pfaff
- Laboratory for Neurobiology and Behavior, the Rockefeller University, New York, NY 10065, United States
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85
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Qiu MH, Chen MC, Fuller PM, Lu J. Stimulation of the Pontine Parabrachial Nucleus Promotes Wakefulness via Extra-thalamic Forebrain Circuit Nodes. Curr Biol 2016; 26:2301-12. [PMID: 27546576 DOI: 10.1016/j.cub.2016.07.054] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/09/2016] [Accepted: 07/20/2016] [Indexed: 01/08/2023]
Abstract
Human and animal studies have identified an especially critical role for the brainstem parabrachial (PB) complex in regulating electrocortical (electroencephalogram [EEG]) and behavioral arousal: lesions of the PB complex produce a monotonous high-voltage, slow-wave EEG and eliminate spontaneous behaviors. We report here that targeted chemogenetic activation of the PB complex produces sustained EEG and behavioral arousal in the rat. We further establish, using viral-mediated retrograde activation, that PB projections to the preoptic-basal forebrain and lateral hypothalamus, but not to the thalamus, mediate PB-driven wakefulness. We exploited this novel and noninvasive model of induced wakefulness to explore the EEG and metabolic consequences of extended wakefulness. Repeated (daily) chemogenetic activation of the PB was highly effective in extending wakefulness over 4 days, although subsequent PB activation produced progressively lesser wake amounts. Curiously, no EEG or behavioral sleep rebound was observed, even after 4 days of induced wakefulness. Following the last of the four daily induced wake bouts, we examined the brains and observed a chimeric pattern of c-Fos expression, with c-Fos expressed in subsets of both arousal- and sleep-promoting nuclei. From a metabolic standpoint, induced extended wakefulness significantly reduced body weight and leptin but was without significant effect on cholesterol, triglyceride, or insulin levels, suggesting that high sleep pressure or sleep debt per se does not, as previously implicated, result in a deleterious metabolic phenotype.
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Affiliation(s)
- Mei Hong Qiu
- Department of Neurobiology, School of Basic Medical Science, Fudan University, Shanghai 200032, China; Department of Pharmacology, School of Basic Medical Science, Fudan University, Shanghai 200032, China; Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA.
| | - Michael C Chen
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
| | - Patrick M Fuller
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
| | - Jun Lu
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA.
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86
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Miyata K, Kuwaki T, Ootsuka Y. The integrated ultradian organization of behavior and physiology in mice and the contribution of orexin to the ultradian patterning. Neuroscience 2016; 334:119-133. [PMID: 27491480 DOI: 10.1016/j.neuroscience.2016.07.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 11/15/2022]
Abstract
Our series of rat experiments have shown that locomotor activity, arousal level, body and brown adipose tissue temperatures, heart rate and arterial pressure increase episodically in an integrated manner approximately every 100min (ultradian manner). Although it has been proposed that the integrated ultradian pattern is a fundamental biological rhythm across species, there are no reports of the integrated ultradian pattern in species other than rats. The aim of the present study was to establish a mouse model using simultaneous recording of locomotor activity, eating behavior, body temperature, heart rate and arousal in order to determine whether their behavior and physiology are organized in an ultradian manner in normal (wild-type) mice. We also incorporated the same recording in prepro-orexin knockout (ORX-KO) mice to reveal the role of orexin in the brain mechanisms underlying ultradian patterning. The orexin system is one of the key conductors required for coordinating autonomic functions and behaviors, and thus may contribute to ultradian patterning. In wild-type mice, locomotor activity, arousal level, body temperature and heart rate increased episodically every 93±18min (n=8) during 24h. Eating was integrated into the ultradian pattern, commencing 23±4min (n=8) after the onset of an electroencephalogram (EEG) ultradian episode. The integrated ultradian pattern in wild-type mice is very similar to that observed in rats. In ORX-KO mice, the ultradian episodic changes in locomotor activity, EEG arousal indices and body temperature were significantly attenuated, but the ultradian patterning was preserved. Our findings support the view that the ultradian pattern is common across species. The present results also suggest that orexin contributes to driving ultradian episodic changes, however, this neuropeptide is not essential for the generation of the ultradian pattern.
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Affiliation(s)
- Kohei Miyata
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Youichirou Ootsuka
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan; Centre for Neuroscience, Department of Human Physiology, School of Medicine, Flinders University, South Australia, Australia.
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87
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Abstract
To understand brain function, it is essential that we discover how cellular signaling specifies normal and pathological brain function. In this regard, chemogenetic technologies represent valuable platforms for manipulating neuronal and non-neuronal signal transduction in a cell-type-specific fashion in freely moving animals. Designer Receptors Exclusively Activated by Designer Drugs (DREADD)-based chemogenetic tools are now commonly used by neuroscientists to identify the circuitry and cellular signals that specify behavior, perceptions, emotions, innate drives, and motor functions in species ranging from flies to nonhuman primates. Here I provide a primer on DREADDs highlighting key technical and conceptual considerations and identify challenges for chemogenetics going forward.
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88
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GABA Receptors on Orexin and Melanin-Concentrating Hormone Neurons Are Differentially Homeostatically Regulated Following Sleep Deprivation. eNeuro 2016; 3:eN-NWR-0077-16. [PMID: 27294196 PMCID: PMC4899679 DOI: 10.1523/eneuro.0077-16.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/25/2016] [Accepted: 05/27/2016] [Indexed: 11/21/2022] Open
Abstract
Though overlapping in distribution through the hypothalamus, orexin (Orx) and melanin-concentrating hormone (MCH) neurons play opposite roles in the regulation of sleep-wake states. Orx neurons discharge during waking, whereas MCH neurons discharge during sleep. In the present study, we examined in mice whether GABAA and GABAB receptors (Rs) are present on Orx and MCH neurons and might undergo differential changes as a function of their different activities following sleep deprivation (SD) and sleep recovery (SR). Applying quantitative stereological image analysis to dual-immunofluorescent stained sections, we determined that the proportion of Orx neurons positively immunostained for GABAARs was significantly higher following SD (∼48%) compared with sleep control (SC; ∼24%) and SR (∼27%), and that the luminance of the GABAARs was significantly greater. In contrast, the average proportion of the MCH neurons immunostained for GABAARs was insignificantly lower following SD (∼43%) compared with SC (∼54%) and SR (56%), and the luminance of the GABAARs was significantly less. Although, GABABRs were observed in all Orx and MCH neurons (100%), the luminance of these receptors was differentially altered following SD. The intensity of GABABRs in the Orx neurons was significantly greater after SD than after SC and SR, whereas that in the MCH neurons was significantly less. The present results indicate that GABA receptors undergo dynamic and differential changes in the wake-active Orx neurons and the sleep-active MCH neurons as a function of and homeostatic adjustment to their preceding activity and sleep-wake state.
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89
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Miyamoto D, Hirai D, Fung CCA, Inutsuka A, Odagawa M, Suzuki T, Boehringer R, Adaikkan C, Matsubara C, Matsuki N, Fukai T, McHugh TJ, Yamanaka A, Murayama M. Top-down cortical input during NREM sleep consolidates perceptual memory. Science 2016; 352:1315-8. [DOI: 10.1126/science.aaf0902] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 05/12/2016] [Indexed: 12/30/2022]
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90
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Kumar A, Chanana P, Choudhary S. Emerging role of orexin antagonists in insomnia therapeutics: An update on SORAs and DORAs. Pharmacol Rep 2016; 68:231-42. [DOI: 10.1016/j.pharep.2015.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 12/28/2022]
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91
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Korim WS, Llewellyn-Smith IJ, Verberne AJM. Activation of Medulla-Projecting Perifornical Neurons Modulates the Adrenal Sympathetic Response to Hypoglycemia: Involvement of Orexin Type 2 (OX2-R) Receptors. Endocrinology 2016; 157:810-9. [PMID: 26653571 DOI: 10.1210/en.2015-1712] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Iatrogenic hypoglycemia in response to insulin treatment is commonly experienced by patients with type 1 diabetes and can be life threatening. The body releases epinephrine in an attempt to counterregulate hypoglycemia, but the neural mechanisms underlying this phenomenon remain to be elucidated. Orexin neurons in the perifornical hypothalamus (PeH) project to the rostral ventrolateral medulla (RVLM) and are likely to be involved in epinephrine secretion during hypoglycemia. In anesthetized rats, we report that hypoglycemia increases the sympathetic preganglionic discharge to the adrenal gland by activating PeH orexin neurons that project to the RVLM (PeH-RVLM). Electrophysiological characterization shows that the majority of identified PeH-RVLM neurons, including a subpopulation of orexin neurons, are activated in response to hypoglycemia or glucoprivation. Furthermore, the excitatory input from the PeH is mediated by orexin type 2 receptors in the RVLM. These results suggest that activation of orexin PeH-RVLM neurons and orexin type 2 receptors in the RVLM facilitates epinephrine release by increasing sympathetic drive to adrenal chromaffin cells during hypoglycemia.
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Affiliation(s)
- Willian S Korim
- Clinical Pharmacology and Therapeutics Unit (W.S.K., A.J.M.V.), Department of Medicine Austin Health, University of Melbourne, Heidelberg, Victoria 3084, Australia; Florey Institute of Neuroscience and Mental Health (W.S.K.), University of Melbourne, Parkville, Victoria 3052, Australia; and Cardiovascular Medicine (I.J.L.-S.), Human Physiology and Centre for Neuroscience, School of Medicine, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Ida J Llewellyn-Smith
- Clinical Pharmacology and Therapeutics Unit (W.S.K., A.J.M.V.), Department of Medicine Austin Health, University of Melbourne, Heidelberg, Victoria 3084, Australia; Florey Institute of Neuroscience and Mental Health (W.S.K.), University of Melbourne, Parkville, Victoria 3052, Australia; and Cardiovascular Medicine (I.J.L.-S.), Human Physiology and Centre for Neuroscience, School of Medicine, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Anthony J M Verberne
- Clinical Pharmacology and Therapeutics Unit (W.S.K., A.J.M.V.), Department of Medicine Austin Health, University of Melbourne, Heidelberg, Victoria 3084, Australia; Florey Institute of Neuroscience and Mental Health (W.S.K.), University of Melbourne, Parkville, Victoria 3052, Australia; and Cardiovascular Medicine (I.J.L.-S.), Human Physiology and Centre for Neuroscience, School of Medicine, Flinders University, Bedford Park, South Australia 5042, Australia
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92
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Black SW, Yamanaka A, Kilduff TS. Challenges in the development of therapeutics for narcolepsy. Prog Neurobiol 2015; 152:89-113. [PMID: 26721620 DOI: 10.1016/j.pneurobio.2015.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 11/14/2015] [Accepted: 12/04/2015] [Indexed: 01/19/2023]
Abstract
Narcolepsy is a neurological disorder that afflicts 1 in 2000 individuals and is characterized by excessive daytime sleepiness and cataplexy-a sudden loss of muscle tone triggered by positive emotions. Features of narcolepsy include dysregulation of arousal state boundaries as well as autonomic and metabolic disturbances. Disruption of neurotransmission through the hypocretin/orexin (Hcrt) system, usually by degeneration of the HCRT-producing neurons in the posterior hypothalamus, results in narcolepsy. The cause of Hcrt neurodegeneration is unknown but thought to be related to autoimmune processes. Current treatments for narcolepsy are symptomatic, including wake-promoting therapeutics that increase presynaptic dopamine release and anticataplectic agents that activate monoaminergic neurotransmission. Sodium oxybate is the only medication approved by the US Food and Drug Administration that alleviates both sleep/wake disturbances and cataplexy. Development of therapeutics for narcolepsy has been challenged by historical misunderstanding of the disease, its many disparate symptoms and, until recently, its unknown etiology. Animal models have been essential to elucidating the neuropathology underlying narcolepsy. These models have also aided understanding the neurobiology of the Hcrt system, mechanisms of cataplexy, and the pharmacology of narcolepsy medications. Transgenic rodent models will be critical in the development of novel therapeutics for the treatment of narcolepsy, particularly efforts directed to overcome challenges in the development of hypocretin replacement therapy.
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Affiliation(s)
- Sarah Wurts Black
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA 94025, USA
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Thomas S Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA 94025, USA.
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93
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Zha X, Xu X. Dissecting the hypothalamic pathways that underlie innate behaviors. Neurosci Bull 2015; 31:629-48. [PMID: 26552801 PMCID: PMC5563731 DOI: 10.1007/s12264-015-1564-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022] Open
Abstract
Many complex behaviors that do not require learning are displayed and are termed innate. Although traditionally the subject matter of ethology, innate behaviors offer a unique entry point for neuroscientists to dissect the physiological mechanisms governing complex behaviors. Since the last century, converging evidence has implicated the hypothalamus as the central brain area that controls innate behaviors. Recent studies using cutting-edge tools have revealed that genetically-defined populations of neurons residing in distinct hypothalamic nuclei and their associated neural pathways regulate the initiation and maintenance of diverse behaviors including feeding, sleep, aggression, and parental care. Here, we review the newly-defined hypothalamic pathways that regulate each innate behavior. In addition, emerging general principles of the neural control of complex behaviors are discussed.
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Affiliation(s)
- Xi Zha
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaohong Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.
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94
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Katayama K, Mochizuki A, Kato T, Ikeda M, Ikawa Y, Nakamura S, Nakayama K, Wakabayashi N, Baba K, Inoue T. Dark/light transition and vigilance states modulate jaw-closing muscle activity level in mice. Neurosci Res 2015; 101:24-31. [DOI: 10.1016/j.neures.2015.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/10/2015] [Accepted: 07/06/2015] [Indexed: 11/26/2022]
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95
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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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96
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Lewis LD, Voigts J, Flores FJ, Schmitt LI, Wilson MA, Halassa MM, Brown EN. Thalamic reticular nucleus induces fast and local modulation of arousal state. eLife 2015; 4:e08760. [PMID: 26460547 PMCID: PMC4686423 DOI: 10.7554/elife.08760] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 09/24/2015] [Indexed: 02/06/2023] Open
Abstract
During low arousal states such as drowsiness and sleep, cortical neurons exhibit rhythmic slow wave activity associated with periods of neuronal silence. Slow waves are locally regulated, and local slow wave dynamics are important for memory, cognition, and behaviour. While several brainstem structures for controlling global sleep states have now been well characterized, a mechanism underlying fast and local modulation of cortical slow waves has not been identified. Here, using optogenetics and whole cortex electrophysiology, we show that local tonic activation of thalamic reticular nucleus (TRN) rapidly induces slow wave activity in a spatially restricted region of cortex. These slow waves resemble those seen in sleep, as cortical units undergo periods of silence phase-locked to the slow wave. Furthermore, animals exhibit behavioural changes consistent with a decrease in arousal state during TRN stimulation. We conclude that TRN can induce rapid modulation of local cortical state. DOI:http://dx.doi.org/10.7554/eLife.08760.001 We usually think of sleep as a global state: that the entire brain is either asleep or awake. However, recent evidence has suggested that smaller regions of the brain can show sleep-like activity while the rest of the brain remains awake. It is not clear why or how these sleep-like patterns of brain activity appear, and whether they are related to the drowsy behaviour that occurs when one is about to fall asleep. Lewis, Voigts et al. investigated how this process works in mice using a technique called optogenetics. This technique makes it possible to genetically engineer mice so that the activity of particular areas of the brain can be switched on or off by light. Lewis, Voigts et al. used light to stimulate different regions of the brain and tracked the resulting brain activity using tiny electrodes that are capable of detecting the activity of individual neurons. The experiments show that stimulating one part of a deep brain structure called the thalamic reticular nucleus causes just one small part of the brain to switch from being awake to producing sleep-like brain wave patterns. When a larger area is stimulated, the whole brain switches into this sleep-like pattern. Stimulation of the thalamic reticular nucleus also caused the animals to become drowsy and they were more likely to fall asleep, which suggests that sleep-like activity in small parts of the brain may contribute to drowsiness. Lewis, Voigts et al.’s findings identify a brain switch that can influence whether an animal is awake or asleep. Importantly, they show that sleep can be independently controlled in small brain regions, and that the thalamic reticular nucleus contains a ‘map’ that allows it to induce sleep in just one region, or across the whole brain. Memories are strengthened during sleep, so the next challenge is to study whether the thalamic reticular nucleus influences memory formation. The findings also suggest that further study of this brain region may be useful for understanding how the sleep and awake states are controlled by particular neurons. DOI:http://dx.doi.org/10.7554/eLife.08760.002
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Affiliation(s)
- Laura D Lewis
- Society of Fellows, Harvard University, Cambridge, United States.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Jakob Voigts
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Francisco J Flores
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,Department of Anesthesia, Harvard Medical School, Boston, United States.,Department of Anesthesia, Massachusetts General Hospital, Boston, United States
| | - L Ian Schmitt
- Neuroscience Institute, New York University, New York, United States
| | - Matthew A Wilson
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Michael M Halassa
- Neuroscience Institute, New York University, New York, United States
| | - Emery N Brown
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,Department of Anesthesia, Harvard Medical School, Boston, United States.,Department of Anesthesia, Massachusetts General Hospital, Boston, United States.,Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, United States
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97
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Miyamoto D, Murayama M. The fiber-optic imaging and manipulation of neural activity during animal behavior. Neurosci Res 2015; 103:1-9. [PMID: 26427958 DOI: 10.1016/j.neures.2015.09.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 12/12/2022]
Abstract
Recent progress with optogenetic probes for imaging and manipulating neural activity has further increased the relevance of fiber-optic systems for neural circuitry research. Optical fibers, which bi-directionally transmit light between separate sites (even at a distance of several meters), can be used for either optical imaging or manipulating neural activity relevant to behavioral circuitry mechanisms. The method's flexibility and the specifications of the light structure are well suited for following the behavior of freely moving animals. Furthermore, thin optical fibers allow researchers to monitor neural activity from not only the cortical surface but also deep brain regions, including the hippocampus and amygdala. Such regions are difficult to target with two-photon microscopes. Optogenetic manipulation of neural activity with an optical fiber has the advantage of being selective for both cell-types and projections as compared to conventional electrophysiological brain tissue stimulation. It is difficult to extract any data regarding changes in neural activity solely from a fiber-optic manipulation device; however, the readout of data is made possible by combining manipulation with electrophysiological recording, or the simultaneous application of optical imaging and manipulation using a bundle-fiber. The present review introduces recent progress in fiber-optic imaging and manipulation methods, while also discussing fiber-optic system designs that are suitable for a given experimental protocol.
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Affiliation(s)
- Daisuke Miyamoto
- Behavioral Neurophysiology Laboratory, Brain Science Institute, Riken, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Masanori Murayama
- Behavioral Neurophysiology Laboratory, Brain Science Institute, Riken, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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98
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Graebner AK, Iyer M, Carter ME. Understanding how discrete populations of hypothalamic neurons orchestrate complicated behavioral states. Front Syst Neurosci 2015; 9:111. [PMID: 26300745 PMCID: PMC4523943 DOI: 10.3389/fnsys.2015.00111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 07/16/2015] [Indexed: 01/01/2023] Open
Abstract
A major question in systems neuroscience is how a single population of neurons can interact with the rest of the brain to orchestrate complex behavioral states. The hypothalamus contains many such discrete neuronal populations that individually regulate arousal, feeding, and drinking. For example, hypothalamic neurons that express hypocretin (Hcrt) neuropeptides can sense homeostatic and metabolic factors affecting wakefulness and orchestrate organismal arousal. Neurons that express agouti-related protein (AgRP) can sense the metabolic needs of the body and orchestrate a state of hunger. The organum vasculosum of the lamina terminalis (OVLT) can detect the hypertonicity of blood and orchestrate a state of thirst. Each hypothalamic population is sufficient to generate complicated behavioral states through the combined efforts of distinct efferent projections. The principal challenge to understanding these brain systems is therefore to determine the individual roles of each downstream projection for each behavioral state. In recent years, the development and application of temporally precise, genetically encoded tools has greatly improved our understanding of the structure and function of these neural systems. This review will survey recent advances in our understanding of how these individual hypothalamic populations can orchestrate complicated behavioral states due to the combined efforts of individual downstream projections.
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Affiliation(s)
- Allison K Graebner
- Program in Neuroscience, Department of Biology, Williams College Williamstown, MA, USA
| | - Manasi Iyer
- Program in Neuroscience, Department of Biology, Williams College Williamstown, MA, USA
| | - Matthew E Carter
- Program in Neuroscience, Department of Biology, Williams College Williamstown, MA, USA
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99
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Fuller PM, Yamanaka A, Lazarus M. How genetically engineered systems are helping to define, and in some cases redefine, the neurobiological basis of sleep and wake. Temperature (Austin) 2015; 2:406-17. [PMID: 27227054 PMCID: PMC4843941 DOI: 10.1080/23328940.2015.1075095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 07/13/2015] [Accepted: 07/15/2015] [Indexed: 10/29/2022] Open
Abstract
The advent of genetically engineered systems, including transgenic animals and recombinant viral vectors, has facilitated a more detailed understanding of the molecular and cellular substrates regulating brain function. In this review we highlight some of the most recent molecular biology and genetic technologies in the experimental "systems neurosciences," many of which are rapidly becoming a methodological standard, and focus in particular on those tools and techniques that permit the reversible and cell-type specific manipulation of neurons in behaving animals. These newer techniques encompass a wide range of approaches including conditional deletion of genes based on Cre/loxP technology, gene silencing using RNA interference, cell-type specific mapping or ablation and reversible manipulation (silencing and activation) of neurons in vivo. Combining these approaches with viral vector delivery systems, in particular adeno-associated viruses (AAV), has extended, in some instances greatly, the utility of these tools. For example, the spatially- and/or temporally-restricted transduction of specific neuronal cell populations is now routinely achieved using the combination of Cre-driver mice and stereotaxic-based delivery of AAV expressing Cre-dependent cassettes. We predict that the experimental application of these tools, including creative combinatorial approaches and the development of even newer reagents, will prove necessary for a complete understanding of the neuronal circuits subserving most neurobiological functions, including the regulation of sleep and wake.
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Affiliation(s)
- Patrick M Fuller
- Department of Neurology; Beth Israel Deaconess Medical Center; Division of Sleep Medicine; Harvard Medical School; Boston, MA USA
| | - Akihiro Yamanaka
- Department of Neuroscience II; Research Institute of Environmental Medicine; Nagoya University; Nagoya, Aichi, Japan
| | - Michael Lazarus
- International Institute for Integrative Sleep Medicine; University of Tsukuba; Tsukuba, Ibaraki, Japan
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100
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Nussinovitch U, Gepstein L. Optogenetics for suppression of cardiac electrical activity in human and rat cardiomyocyte cultures. NEUROPHOTONICS 2015; 2:031204. [PMID: 26158013 PMCID: PMC4478752 DOI: 10.1117/1.nph.2.3.031204] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 05/19/2015] [Indexed: 06/04/2023]
Abstract
Optogenetics has revolutionized neuroscience by enabling precise control of neural excitation. The development of similar optogenetics strategies in the heart is just emerging and mainly focused on pacing with light activation of channelrhodopsin-2. Here, we aimed to develop an optogenetic approach to suppress local cardiac electrical activity by using engineered cell-grafts (HEK293-cells) transfected to express the light-sensitive hyperpolarizing proton-pump archaerhodopsin-3 (Arch3). To evaluate the ability of the engineered cells to couple and modulate the electrical activity of cardiomyocytes, we co-cultured the Arch3-HEK293 cells with neonatal rat cardiomyocytes (NRCMs) or human embryonic stem cells derived cardiomyocytes (hESC-CMs). The co-cultures' conduction and chronotropic properties were evaluated prior, during, and following application of focused monochromatic light (590 nm) using a multielectrode array mapping system. Application of focused illumination completely silenced electrical activity at the illuminated area in all NRCM co-cultures, leading to development of localized functional conduction blocks. Similarly, illumination significantly slowed spontaneous beating-rate in the hESCs-CMs co-cultures (from [Formula: see text] to [Formula: see text], [Formula: see text]). Interestingly, a transient acceleration in beating-rate was noted immediately postillumination. In conclusion, a combined gene and cell therapy approach, using light-sensitive hyperpolarizing proteins, could be used to modulate conduction and automaticity in cardiomyocyte cultures, opening the way for future optogenetic treatments for cardiac tachyarrhythmias.
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Affiliation(s)
- Udi Nussinovitch
- Technion-Israel Institute of Technology, Sohnis Family Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, POB 9649, Haifa 31093, Israel
- Rambam Health Care Campus, Department of Internal Medicine A, Haifa 31096, Israel
| | - Lior Gepstein
- Technion-Israel Institute of Technology, Sohnis Family Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, POB 9649, Haifa 31093, Israel
- Rambam Health Care Campus, Cardiology Department, Haifa 31096, Israel
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