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Carrera-Cañas C, de Andrés I, Callejo M, Garzón M. Plasticity of the hypocretinergic/orexinergic system after a chronic treatment with suvorexant in rats. Role of the hypocretinergic/orexinergic receptor 1 as an autoreceptor. Front Mol Neurosci 2022; 15:1013182. [PMID: 36277486 PMCID: PMC9581150 DOI: 10.3389/fnmol.2022.1013182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/13/2022] [Indexed: 12/02/2022] Open
Abstract
The hypothalamic hypocretinergic/orexinergic (Hcrt/Ox) system is involved in many physiological and pathophysiological processes. Malfunction of Hcrt/Ox transmission results in narcolepsy, a sleep disease caused in humans by progressive neurodegeneration of hypothalamic neurons containing Hcrt/Ox. To explore the Hcrt/Ox system plasticity we systemically administered suvorexant (a dual Hcrt/Ox receptor antagonist) in rats to chronically block Hcrt/Ox transmission without damaging Hcrt/Ox cells. Three groups of eight rats (four males and four females) received daily i.p. injections of suvorexant (10 or 30 mg/kg) or vehicle (DMSO) over a period of 7 days in which the body weight was monitored. After the treatments cerebrospinal fluid (CSF) Hcrt1/OxA concentration was measured by ELISA, and hypothalamic Hcrt/OxR1 and Hcrt/OxR2 levels by western blot. The systemic blockade of the Hcrt/Ox transmission with the suvorexant high dose produced a significant increase in body weight at the end of the treatment, and a significant decrease in CSF Hcrt1/OxA levels, both features typical in human narcolepsy type 1. Besides, a significant overexpression of hypothalamic Hcrt/OxR1 occurred. For the Hcrt/OxR2 two very close bands were detected, but they did not show significant changes with the treatment. Thus, the plastic changes observed in the Hcrt/Ox system after the chronic blockade of its transmission were a decrease in CSF Hcrt1/OXA levels and an overexpression of hypothalamic Hcrt/OxR1. These findings support an autoregulatory role of Hcrt/OxR1 within the hypothalamus, which would induce the synthesis/release of Hcrt/Ox, but also decrease its own availability at the plasma membrane after binding Hcrt1/OxA to preserve Hcrt/Ox system homeostasis.
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Kousi C, Lampri E, Voulgaris S, Vougiouklakis T, Galani V, Mitselou A. Expression of orexin-A (hypocretin-A) in the hypothalamus after traumatic brain injury: A postmortem evaluation. Forensic Sci Int 2021; 327:110961. [PMID: 34454377 DOI: 10.1016/j.forsciint.2021.110961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/16/2021] [Accepted: 08/17/2021] [Indexed: 01/01/2023]
Abstract
Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity. The key component of TBI pathophysiology is traumatic axonal injury (TAI), commonly referred to as diffuse axonal injury (DAI). Coma is a serious complication which can occur following traumatic brain injury (TBI). Recently, studies have shown that the central orexinergic/ hypocretinergic system exhibit prominent arousal promoting actions. Therefore, the purpose of this study is to investigate by immunohistochemistry the expression of beta-amyloid precursor protein (β-APP) in white matter of parasagittal region, corpus callosum and brainstem and the expression of orexin-A (ORXA) in the hypothalamus after traumatic brain injury. RESULTS: DAI was found in 26 (53.06%) cases, assessed with β-APP immunohistochemical staining in parasagittal white matter, corpus callosum and brainstem. Orexin-A immunoreactivity in hypothalamus was completely absent in 5 (10.2%) of the cases; moderate reduction of ORXA was observed in 9 (18.4%) of the cases; and severe reduction was observed in 7 (14.3%) of the cases. A statistically significant correlation was found between β-APP immunostaining in white matter, corpus callosum and brainstem in relation to survival time (p < 0.002, p < 0.003 and p < 0.005 respectively). A statistically positive correlation was noted between ORX-A immunoreactivity in hypothalamus to survival time (p < 0.003). An inverse correlation was noted between the expression of β-APP in the regions of brain studied to the expression of ORX-A in the hypothalamus of the cases studied (p < 0.005). CONCLUSIONS: The present study demonstrated by immunohistochemistry that reduction of orexin-A neurons in the hypothalamus, involved in coma status and arousal, enhanced the immunoexpression of β-APP in parasagital white matter, corpus callosum and brainstem.
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Affiliation(s)
- Chrysavgi Kousi
- Department of Forensic Medicine and Toxicology Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Evangeli Lampri
- Department of Pathology Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Spyridon Voulgaris
- Department of Neurosurgery, Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Theodoros Vougiouklakis
- Department of Forensic Medicine and Toxicology Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Vassiliki Galani
- Department of Anatomy-Histology-Embryology, University of Ioannina, Greece.
| | - Antigony Mitselou
- Department of Forensic Medicine and Toxicology Health Sciences, School of Medicine, University of Ioannina, Greece
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Carrera-Cañas C, Garzón M, de Andrés I. The Transition Between Slow-Wave Sleep and REM Sleep Constitutes an Independent Sleep Stage Organized by Cholinergic Mechanisms in the Rostrodorsal Pontine Tegmentum. Front Neurosci 2019; 13:748. [PMID: 31396036 PMCID: PMC6663996 DOI: 10.3389/fnins.2019.00748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/05/2019] [Indexed: 12/11/2022] Open
Abstract
There is little information on either the transition state occurring between slow-wave sleep (SWS) and rapid eye movement (REM) sleep, as well as about its neurobiological bases. This transition state, which is known as the intermediate state (IS), is well-defined in rats but poorly characterized in cats. Previous studies in our laboratory demonstrated that cholinergic stimulation of the perilocus coeruleus α nucleus (PLCα) in the pontine tegmentum of cats induced two states: wakefulness with muscle atonia and a state of dissociated sleep we have called the SPGO state. The SPGO state has characteristics in common with the IS, such including the presence of ponto-geniculo-occipital waves (PGO) and EEG synchronization with δ wave reduction. Therefore, the aims of the present study were (1) to characterize the IS in the cat and, (2), to study the analogy between the SPGO and the different sleep stages showing PGO activity, including the IS. Polygraphic recordings of 10 cats were used. In seven cats carbachol microinjections (20-30 nL, 0.01-0.1 M) were delivered in the PLCα. In the different states, PGO waves were analyzed and power spectra obtained for the δ, θ, α, and β bands of the EEG from the frontal and occipital cortices, and for the θ hippocampal band. Statistical comparisons were made between the values obtained from the different states. The results indicate that the IS constitutes a state with characteristics that are distinct from both the preceding SWS and the following REM sleep, and that SPGO presents a high analogy with the IS. Therefore, the SPGO state induced by administering carbachol in the PLCα nucleus seems to be an expression of the physiological IS of the cat. Consequently, we propose that the PLCα region, besides being involved in the mechanisms of muscle atonia, may also be responsible for organizing the transition from SWS to REM sleep.
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Affiliation(s)
| | | | - Isabel de Andrés
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
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Garzón M, Pickel VM. Electron microscopic localization of M2-muscarinic receptors in cholinergic and noncholinergic neurons of the laterodorsal tegmental and pedunculopontine nuclei of the rat mesopontine tegmentum. J Comp Neurol 2016; 524:3084-103. [PMID: 27038330 DOI: 10.1002/cne.24010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 03/02/2016] [Accepted: 03/28/2016] [Indexed: 01/01/2023]
Abstract
Muscarinic m2 receptors (M2Rs) are implicated in autoregulatory control of cholinergic output neurons located within the pedunculopontine (PPT) and laterodorsal tegmental (LTD) nuclei of the mesopontine tegmentum (MPT). However, these nuclei contain many noncholinergic neurons in which activation of M2R heteroceptors may contribute significantly to the decisive role of the LTD and PPT in sleep-wakefulness. We examined the electron microscopic dual immunolabeling of M2Rs and the vesicular acetylcholine transporter (VAchT) in the MPT of rat brain to identify the potential sites for M2R activation. M2R immunogold labeling was predominately seen in somatodendritic profiles throughout the PPT/LTD complex. In somata, M2R immunogold particles were often associated with Golgi lamellae and cytoplasmic endomembrannes, but were rarely in contact with the plasma membrane, as was commonly seen in dendrites. Approximately 36% of the M2R-labeled somata and 16% of the more numerous M2R-labeled dendrites coexpressed VAchT. M2R and M2R/VAchT-labeled dendritic profiles received synapses from inhibitory- and excitatory-type axon terminals, over 88% of which were unlabeled and others contained exclusively M2R or VAchT immunoreactivity. In axonal profiles M2R immunogold was localized to plasmalemmal and cytoplasmic regions and showed a similar distribution in many VAchT-negative glial profiles. These results provide ultrastructural evidence suggestive of somatic endomembrane trafficking of M2Rs, whose activation serves to regulate the postsynaptic excitatory and inhibitory responses in dendrites of cholinergic and noncholinergic neurons in the MPT. They also suggest the possibility that M2Rs in this brain region mediate the effects of acetylcholine on the release of other neurotransmitters and on glial signaling. J. Comp. Neurol. 524:3084-3103, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Miguel Garzón
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina UAM, Madrid, Spain.,Instituto de Investigación Hospital Universitario La Paz (IDIPAZ), Madrid, Spain.,Department of Neuroscience, Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Virginia M Pickel
- Department of Neuroscience, Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
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ZHONG YINGJUN, FENG ZHEN, WANG LIANG, WEI TIANQI. Wake-promoting actions of median nerve stimulation in TBI-induced coma: An investigation of orexin-A and orexin receptor 1 in the hypothalamic region. Mol Med Rep 2015; 12:4441-4447. [DOI: 10.3892/mmr.2015.3898] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 05/08/2015] [Indexed: 11/06/2022] Open
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Del Cid-Pellitero E, Garzón M. Hypocretin1/orexinA-immunoreactive axons form few synaptic contacts on rat ventral tegmental area neurons that project to the medial prefrontal cortex. BMC Neurosci 2014; 15:105. [PMID: 25194917 PMCID: PMC4167264 DOI: 10.1186/1471-2202-15-105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 08/28/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypocretins/orexins (Hcrt/Ox) are hypothalamic neuropeptides involved in sleep-wakefulness regulation. Deficiency in Hcrt/Ox neurotransmission results in the sleep disorder narcolepsy, which is characterized by an inability to maintain wakefulness. The Hcrt/Ox neurons are maximally active during wakefulness and project widely to the ventral tegmental area (VTA). A dopamine-containing nucleus projecting extensively to the cerebral cortex, the VTA enhances wakefulness. In the present study, we used retrograde tracing from the medial prefrontal cortex (mPFC) to examine whether Hcrt1/OxA neurons target VTA neurons that could sustain behavioral wakefulness through their projections to mPFC. RESULTS The retrograde tracer Fluorogold (FG) was injected into mPFC and, after an optimal survival period, sections through the VTA were processed for dual immunolabeling of anti-FG and either anti-Hcrt1/OxA or anti-TH antisera. Most VTA neurons projecting to the mPFC were located in the parabrachial nucleus of the ipsilateral VTA and were non-dopaminergic. Only axonal profiles showed Hcrt1/OxA-immunoreactivity in VTA. Hcrt1/OxA reactivity was observed in axonal boutons and many unmyelinated axons. The Hcrt1/OxA immunoreactivity was found filling axons but it was also observed in parts of the cytoplasm and dense-core vesicles. Hcrt1/OxA-labeled boutons frequently apposed FG-immunolabeled dendrites. However, Hcrt1/OxA-labeled boutons rarely established synapses, which, when they were established, were mainly asymmetric (excitatory-type), with either FG-labeled or unlabeled dendrites. CONCLUSIONS Our results provide ultrastructural evidence that Hcrt1/OxA neurons may exert a direct synaptic influence on mesocortical neurons that would facilitate arousal and wakefulness. The paucity of synapses, however, suggest that the activity of VTA neurons with cortical projections might also be modulated by Hcrt1/OxA non-synaptic actions. In addition, Hcrt1/OxA could modulate the postsynaptic excitatory responses of VTA neurons with cortical projections to a co-released excitatory transmitter from Hcrt1/OxA axons. Our observation of Hcrt1/OxA targeting of mesocortical neurons supports Hcrt1/OxA wakefulness enhancement in the VTA and could help explain the characteristic hypersomnia present in narcoleptic patients.
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Affiliation(s)
| | - Miguel Garzón
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, 28029 Madrid, Spain.
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Torterolo P, Chase MH. The hypocretins (orexins) mediate the "phasic" components of REM sleep: A new hypothesis. Sleep Sci 2014; 7:19-29. [PMID: 26483897 PMCID: PMC4521687 DOI: 10.1016/j.slsci.2014.07.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/27/2014] [Indexed: 12/17/2022] Open
Abstract
In 1998, a group of phenotypically distinct neurons were discovered in the postero-lateral hypothalamus which contained the neuropeptides hypocretin 1 and hypocretin 2 (also called orexin A and orexin B), which are excitatory neuromodulators. Hypocretinergic neurons project throughout the central nervous system and have been involved in the generation and maintenance of wakefulness. The sleep disorder narcolepsy, characterized by hypersomnia and cataplexy, is produced by degeneration of these neurons. The hypocretinergic neurons are active during wakefulness in conjunction with the presence of motor activity that occurs during survival-related behaviors. These neurons decrease their firing rate during non-REM sleep; however there is still controversy upon the activity and role of these neurons during REM sleep. Hence, in the present report we conducted a critical review of the literature of the hypocretinergic system during REM sleep, and hypothesize a possible role of this system in the generation of REM sleep.
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Affiliation(s)
- Pablo Torterolo
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, 11800 Montevideo, Uruguay
| | - Michael H. Chase
- WebSciences International, Los Angeles, USA
- UCLA School of Medicine, Los Angeles, USA
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Yi W, Zhang Y, Tian Y, Guo J, Li Y, Guo A. A subset of cholinergic mushroom body neurons requires Go signaling to regulate sleep in Drosophila. Sleep 2013; 36:1809-21. [PMID: 24293755 DOI: 10.5665/sleep.3206] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
STUDY OBJECTIVES Identifying the neurochemistry and neural circuitry of sleep regulation is critical for understanding sleep and various sleep disorders. Fruit flies display sleep-like behavior, sharing essential features with sleep of vertebrate. In the fruit fly's central brain, the mushroom body (MB) has been highlighted as a sleep center; however, its neurochemical nature remains unclear, and whether it promotes sleep or wake is still a topic of controversy. DESIGN We used a video recording system to accurately monitor the locomotor activity and sleep status. Gene expression was temporally and regionally manipulated by heat induction and the Gal4/UAS system. MEASUREMENTS AND RESULTS We found that expressing pertussis toxin (PTX) in the MB by c309-Gal4 to block Go activity led to unique sleep defects as dramatic sleep increase in daytime and fragmented sleep in nighttime. We narrowed down the c309-Gal4 expressing brain regions to the MB α/β core neurons that are responsible for the Go-mediated sleep effects. Using genetic tools of neurotransmitter-specific Gal80 and RNA interference approach to suppress acetylcholine signal, we demonstrated that these MB α/β core neurons were cholinergic and sleep-promoting neurons, supporting that Go mediates an inhibitory signal. Interestingly, we found that adjacent MB α/β neurons were also cholinergic but wake-promoting neurons, in which Go signal was also required. CONCLUSION Our findings in fruit flies characterized a group of sleep-promoting neurons surrounded by a group of wake-promoting neurons. The two groups of neurons are both cholinergic and use Go inhibitory signal to regulate sleep.
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Affiliation(s)
- Wei Yi
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ; University of Chinese Academy of Sciences, Beijing, China
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García-García B, Reinoso-Suárez F, Rodrigo-Angulo ML. Hypothalamic Hypocretinergic/Orexinergic Neurons Projecting to the Oral Pontine Rapid Eye Movement Sleep Inducing Site in the Cat. Anat Rec (Hoboken) 2013; 296:815-21. [DOI: 10.1002/ar.22690] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 12/19/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Berta García-García
- Departamento de Anatomía; Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid; Madrid Spain
| | - Fernando Reinoso-Suárez
- Departamento de Anatomía; Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid; Madrid Spain
| | - Margarita L. Rodrigo-Angulo
- Departamento de Anatomía; Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid; Madrid Spain
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Torterolo P, Sampogna S, Chase MH. Hypocretinergic and non-hypocretinergic projections from the hypothalamus to the REM sleep executive area of the pons. Brain Res 2013; 1491:68-77. [PMID: 23122879 PMCID: PMC3529971 DOI: 10.1016/j.brainres.2012.10.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/19/2012] [Accepted: 10/25/2012] [Indexed: 12/28/2022]
Abstract
Within the postero-lateral hypothalamus neurons that utilize hypocretin or melanin-concentrating hormone (MCH) as neuromodulators are co-distributed. These neurons have been involved in the control of behavioral states, and a deficit in the hypocretinergic system is the pathogenic basis of narcolepsy with cataplexy. In this report, utilizing immunohistochemistry and retrograde tracing techniques, we examined the hypocretinergic innervation of the nucleus pontis oralis (NPO), which is the executive site that is responsible for the generation of REM sleep in the cat. The retrograde tracer cholera toxin subunit b (CTb) was administered in pontine regions where carbachol microinjections induced REM sleep. Utilizing immunohistochemical techniques, we found that approximately 1% of hypocretinergic neurons in the tuberal area of the hypothalamus project to the NPO. In addition, approximately 6% of all CTb+ neurons in this region were hypocretinergic. The hypocretinergic innervation of the NPO was also compared with the innervation of the same site by MCH-containing neurons. More than three times as many MCHergic neurons were found to project to the NPO compared with hypocretinergic cells; both neuronal types exhibited bilateral projections. We also identified a group of non-hypocretinergic non-MCHergic neuronal group of neurons that were intermingled with both hypocretinergic and MCHergic neurons that also projected to this same brainstem region. These neurons were grater in number that either hypocretin or MCH-containing neurons; their soma size was also smaller and their projections were mainly ipsilateral. The present anatomical data suggest that hypocretinergic, MCHergic and an unidentified companion group of neurons of the postero-lateral hypothalamus participate in the regulation of the neuronal activity of NPO neurons, and therefore, are likely to participate in the control of wakefulness and REM sleep.
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Affiliation(s)
- Pablo Torterolo
- Laboratorio de Neurobiología del Sueño, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, General Flores 2125, Montevideo, Uruguay.
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Abstract
The development of sedative/hypnotic molecules has been empiric rather than rational. The empiric approach has produced clinically useful drugs but for no drug is the mechanism of action completely understood. All available sedative/hypnotic medications have unwanted side effects and none of these medications creates a sleep architecture that is identical to the architecture of naturally occurring sleep. This chapter reviews recent advances in research aiming to elucidate the neurochemical mechanisms regulating sleep and wakefulness. One promise of rational drug design is that understanding the mechanisms of sedative/hypnotic action will significantly enhance drug safety and efficacy.
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de Andrés I, Garzón M, Reinoso-Suárez F. Functional Anatomy of Non-REM Sleep. Front Neurol 2011; 2:70. [PMID: 22110467 PMCID: PMC3215999 DOI: 10.3389/fneur.2011.00070] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/26/2011] [Indexed: 11/16/2022] Open
Abstract
The state of non-REM sleep (NREM), or slow wave sleep, is associated with a synchronized EEG pattern in which sleep spindles and/or K complexes and high-voltage slow wave activity (SWA) can be recorded over the entire cortical surface. In humans, NREM is subdivided into stages 2 and 3-4 (presently named N3) depending on the proportions of each of these polygraphic events. NREM is necessary for normal physical and intellectual performance and behavior. An overview of the brain structures involved in NREM generation shows that the thalamus and the cerebral cortex are absolutely necessary for the most significant bioelectric and behavioral events of NREM to be expressed; other structures like the basal forebrain, anterior hypothalamus, cerebellum, caudal brain stem, spinal cord and peripheral nerves contribute to NREM regulation and modulation. In NREM stage 2, sustained hyperpolarized membrane potential levels resulting from interaction between thalamic reticular and projection neurons gives rise to spindle oscillations in the membrane potential; the initiation and termination of individual spindle sequences depends on corticothalamic activities. Cortical and thalamic mechanisms are also involved in the generation of EEG delta SWA that appears in deep stage 3-4 (N3) NREM; the cortex has classically been considered to be the structure that generates this activity, but delta oscillations can also be generated in thalamocortical neurons. NREM is probably necessary to normalize synapses to a sustainable basal condition that can ensure cellular homeostasis. Sleep homeostasis depends not only on the duration of prior wakefulness but also on its intensity, and sleep need increases when wakefulness is associated with learning. NREM seems to ensure cell homeostasis by reducing the number of synaptic connections to a basic level; based on simple energy demands, cerebral energy economizing during NREM sleep is one of the prevalent hypotheses to explain NREM homeostasis.
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Affiliation(s)
- Isabel de Andrés
- Departamento de Anatomía Histología y Neurociencia, Universidad Autónoma de Madrid, Instituto de Investigación Hospital Universitario La PazMadrid, Spain
| | - Miguel Garzón
- Departamento de Anatomía Histología y Neurociencia, Universidad Autónoma de Madrid, Instituto de Investigación Hospital Universitario La PazMadrid, Spain
| | - Fernando Reinoso-Suárez
- Departamento de Anatomía Histología y Neurociencia, Universidad Autónoma de Madrid, Instituto de Investigación Hospital Universitario La PazMadrid, Spain
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Kitka T, Adori C, Katai Z, Vas S, Molnar E, Papp RS, Toth ZE, Bagdy G. Association between the activation of MCH and orexin immunorective neurons and REM sleep architecture during REM rebound after a three day long REM deprivation. Neurochem Int 2011; 59:686-94. [PMID: 21740944 DOI: 10.1016/j.neuint.2011.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 06/16/2011] [Accepted: 06/22/2011] [Indexed: 11/15/2022]
Abstract
Rapid eye movement (REM) sleep rebound following REM deprivation using the platform-on-water method is characterized by increased time spent in REM sleep and activation of melanin-concentrating hormone (MCH) expressing neurons. Orexinergic neurons discharge reciprocally to MCH-ergic neurons across the sleep-wake cycle. However, the relation between REM architecture and the aforementioned neuropeptides remained unclear. MCH-ergic neurons can be divided into two subpopulations regarding their cocaine- and amphetamine-regulated transcript (CART) immunoreactivity, and among them the activation of CART-immunoreactive subpopulation is higher during the REM rebound. However, the possible role of stress in this association has not been elucidated. Our aims were to analyze the relationship between the architecture of REM rebound and the activation of hypothalamic MCH-ergic and orexinergic neurons. We also intended to separate the effect of stress and REM deprivation on the subsequent activation of subpopulations of MCH-ergic neurons. In order to detect neuronal activity, we performed MCH/cFos and orexin/cFos double immunohistochemistry on home cage, sleep deprived and sleep-rebound rats using the platform-on-water method with small and large (stress control) platforms. Furthermore, REM architecture was analyzed and a triple MCH/CART/cFos immunohistochemistry was also performed on the rebound groups in the same animals. We found that the activity of MCH- and orexin-immunoreactive neurons during REM rebound was positively and negatively correlated with the number of REM bouts, respectively. A negative reciprocal correlation was also found between the activation of MCH- and orexin-immunoreactive neurons during REM rebound. Furthermore, difference between the activation of CART-immunoreactive (CART-IR) and non-CART-immunoreactive MCH-ergic neuron subpopulations was found only after selective REM deprivation, it was absent in the large platform (stress control) rebound group. These results support the role of CART-IR subpopulation of MCH-ergic neurons and the inverse relationship of MCH and orexin in the regulation of REM sleep after REM sleep deprivation.
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Affiliation(s)
- Tamas Kitka
- Department of Pharmacodynamics, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary
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Cid-Pellitero ED, Garzon M. Hypocretin1/OrexinA Axon Targeting of Laterodorsal Tegmental Nucleus Neurons Projecting to the Rat Medial Prefrontal Cortex. Cereb Cortex 2011; 21:2762-73. [DOI: 10.1093/cercor/bhr070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Cid-Pellitero ED, GarzÓN M. Hypocretin1/OrexinA-containing axons innervate locus coeruleus neurons that project to the Rat medial prefrontal cortex. Implication in the sleep-wakefulness cycle and cortical activation. Synapse 2011; 65:843-57. [DOI: 10.1002/syn.20912] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 01/09/2010] [Indexed: 12/31/2022]
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Xi M, Chase MH. The injection of hypocretin-1 into the nucleus pontis oralis induces either active sleep or wakefulness depending on the behavioral state when it is administered. Sleep 2010; 33:1236-43. [PMID: 20857871 DOI: 10.1093/sleep/33.9.1236] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES We previously reported that the microinjection of hypocretin (orexin) into the nucleus pontis oralis (NPO) induces a behavioral state that is comparable to naturally occurring active (rapid eye movement) sleep. However, other laboratories have found that wakefulness occurs following injections of hypocretin into the NPO. The present study tested the hypothesis that the discrepancy in behavioral state responses to hypocretin injections is due to the fact that hypocretin was not administered during the same states of sleep or wakefulness. DESIGN Adult cats were implanted with electrodes to record sleep and waking states. Hypocretin-1 (0.25 microL, 500microM) was microinjected into the NPO while the animals were awake or in quiet (non-rapid eye movement) sleep. MEASUREMENTS AND RESULTS When hyprocretin-1 was microinjected into the NPO during quiet sleep, active sleep occurred with a short latency. In addition, there was a significant increase in the time spent in active sleep and in the number of episodes of this state. On the other hand, the injection of hyprocretin-1 during wakefulness resulted not only in a significant increase in wakefulness, but also in a decrease in the percentage and frequency of episodes of active sleep. CONCLUSIONS The present data demonstrate that the behavioral state of the animal dictates whether active sleep or wakefulness is induced following the injection of hypocretin. Therefore, we suggest that hypocretin-1 enhances ongoing states of wakefulness and their accompanying patterns of physiologic activity and that hypocretin-1 is also capable of promoting active sleep and the changes in various processes that occur during this state.
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Affiliation(s)
- Mingchu Xi
- WebSciences International, Los Angeles, CA 90024, USA.
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Brevig HN, Watson CJ, Lydic R, Baghdoyan HA. Hypocretin and GABA interact in the pontine reticular formation to increase wakefulness. Sleep 2010; 33:1285-93. [PMID: 21061850 DOI: 10.1093/sleep/33.10.1285] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
STUDY OBJECTIVES Hypocretin-1/orexin A administered directly into the oral part of rat pontine reticular formation (PnO) causes an increase in wakefulness and extracellular gamma-aminobutyric acid (GABA) levels. The receptors in the PnO that mediate these effects have not been identified. Therefore, this study tested the hypothesis that the increase in wakefulness caused by administration of hypocretin-1 into the PnO occurs via activation of GABAA receptors and hypocretin receptors. DESIGN Within/between subjects. SETTING University of Michigan. PATIENTS OR PARTICIPANTS Twenty-three adult male Crl:CD*(SD) (Sprague Dawley) rats. INTERVENTIONS Microinjection of hypocretin-1, bicuculline (GABAA receptor antagonist), SB-334867 (hypocretin receptor-1 antagonist), and Ringer solution (vehicle control) into the PnO. MEASUREMENTS AND RESULTS Hypocretin-1 caused a significant concentration-dependent increase in wakefulness and decrease in rapid eye movement (REM) sleep and non-REM (NREM) sleep. Coadministration of SB-334867 and hypocretin-1 blocked the hypocretin-1-induced increase in wakefulness and decrease in both the NREM and REM phases of sleep. Coadministration of bicuculline and hypocretin-1 blocked the hypocretin-1-induced increase in wakefulness and decrease in NREM sleep caused by hypocretin-1. CONCLUSION The increase in wakefulness caused by administering hypocretin-1 to the PnO is mediated by hypocretin receptors and GABAA receptors in the PnO. These results show for the first time that hypocretinergic and GABAergic transmission in the PnO can interact to promote wakefulness.
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Affiliation(s)
- Holly N Brevig
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48109-5615, USA
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Abstract
The development of sedative/hypnotic molecules has been empiric rather than rational. The empiric approach has produced clinically useful drugs but for no drug is the mechanism of action completely understood. All available sedative/hypnotic medications have unwanted side effects and none of these medications creates a sleep architecture that is identical to the architecture of naturally occurring sleep. This chapter reviews recent advances in research aiming to elucidate the neurochemical mechanisms regulating sleep and wakefulness. One promise of rational drug design is that understanding the mechanisms of sedative/hypnotic action will significantly enhance drug safety and efficacy.
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Nuñez A, Rodrigo-Angulo ML, Andrés ID, Garzón M. Hypocretin/Orexin neuropeptides: participation in the control of sleep-wakefulness cycle and energy homeostasis. Curr Neuropharmacol 2010; 7:50-9. [PMID: 19721817 PMCID: PMC2724663 DOI: 10.2174/157015909787602797] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 08/19/2008] [Accepted: 09/17/2008] [Indexed: 11/28/2022] Open
Abstract
Hypocretins or orexins (Hcrt/Orx) are hypothalamic neuropeptides that are synthesized by neurons located mainly in the perifornical area of the posterolateral hypothalamus. These hypothalamic neurons are the origin of an extensive and divergent projection system innervating numerous structures of the central nervous system. In recent years it has become clear that these neuropeptides are involved in the regulation of many organic functions, such as feeding, thermoregulation and neuroendocrine and cardiovascular control, as well as in the control of the sleep-wakefulness cycle. In this respect, Hcrt/Orx activate two subtypes of G protein-coupled receptors (Hcrt/Orx1R and Hcrt/Orx2R) that show a partly segregated and prominent distribution in neural structures involved in sleep-wakefulness regulation. Wakefulness-enhancing and/or sleep-suppressing actions of Hcrt/Orx have been reported in specific areas of the brainstem. Moreover, presently there are animal models of human narcolepsy consisting in modifications of Hcrt/Orx receptors or absence of these peptides. This strongly suggests that narcolepsy is the direct consequence of a hypofunction of the Hcrt/Orx system, which is most likely due to Hcrt/Orx neurons degeneration. The main focus of this review is to update and illustrate the available data on the actions of Hcrt/Orx neuropeptides with special interest in their participation in the control of the sleep-wakefulness cycle and the regulation of energy homeostasis. Current pharmacological treatment of narcolepsy is also discussed.
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Affiliation(s)
- A Nuñez
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
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20
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Adamantidis A, Carter MC, de Lecea L. Optogenetic deconstruction of sleep-wake circuitry in the brain. Front Mol Neurosci 2010; 2:31. [PMID: 20126433 PMCID: PMC2814554 DOI: 10.3389/neuro.02.031.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 12/18/2009] [Indexed: 02/04/2023] Open
Abstract
How does the brain regulate the sleep–wake cycle? What are the temporal codes of sleep and wake-promoting neural circuits? How do these circuits interact with each other across the light/dark cycle? Over the past few decades, many studies from a variety of disciplines have made substantial progress in answering these fundamental questions. For example, neurobiologists have identified multiple, redundant wake-promoting circuits in the brainstem, hypothalamus, and basal forebrain. Sleep-promoting circuits have been found in the preoptic area and hypothalamus. One of the greatest challenges in recent years has been to selectively record and manipulate these sleep–wake centers in vivo with high spatial and temporal resolution. Recent developments in microbial opsin-based neuromodulation tools, collectively referred to as “optogenetics,” have provided a novel method to demonstrate causal links between neural activity and specific behaviors. Here, we propose to use optogenetics as a fundamental tool to probe the necessity, sufficiency, and connectivity of defined neural circuits in the regulation of sleep and wakefulness.
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Affiliation(s)
- Antoine Adamantidis
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine Palo Alto, CA, USA
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21
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de la Roza C, Reinoso-Suárez F. Ultrastructural characterization of relationship between serotonergic and GABAergic structures in the ventral part of the oral pontine reticular nucleus. Neuroscience 2009; 164:1180-90. [PMID: 19723566 DOI: 10.1016/j.neuroscience.2009.08.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 08/21/2009] [Accepted: 08/22/2009] [Indexed: 11/25/2022]
Abstract
The ventral part of the oral pontine reticular nucleus (vRPO) is involved in the generation and maintenance of rapid eye movement (REM) sleep. Both GABAergic and serotonergic neurotransmission have been implicated in the control of the sleep-wakefulness cycle. Nevertheless, the synaptic organization of serotonergic terminals in the vRPO has not yet been characterized. We performed an electron microscope study of serotonin-immunoreactive (5-HT-IR) terminals using immunoperoxidase or immunogold-silver methods. In a second set of experiments, combining GABA immunoperoxidase and 5-HT immunogold-silver techniques, we examined inputs from GABA-immunoreactive (GABA-IR) terminals to serotonergic neurons. 5-HT-IR terminals were located primarily on dendrites and occasionally on somata of unlabeled and 5-HT-IR neurons. The majority of the synapses formed by 5-HT-IR terminals were of the symmetrical type, making contacts primarily with unlabeled dendritic profiles. Moreover, 5-HT-IR terminals contacted unlabeled axon terminals that formed asymmetric synapses on dendrites. Double immunolabeling experiments showed 5-HT-IR and GABA-IR afferents, in apposition to each other, making synapses with the same dendrites. Finally, GABA-IR terminals innervated 5-HT-IR and GABA-IR dendrites. Our findings indicate that serotonin would modulate the neuronal activity through inhibitory or excitatory influences, although the action of serotonin on the vRPO would predominantly be inhibitory. Moreover, the present results suggest that the serotonin modulation of vRPO neurons might involve indirect connections. In addition, GABA might contribute to the induction and maintenance of REM sleep by inhibiting serotonergic and GABAergic neurons in the vRPO.
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Affiliation(s)
- C de la Roza
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo, 28029 Madrid, Spain.
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Volgin DV, Malinowska M, Kubin L. Dorsomedial pontine neurons with descending projections to the medullary reticular formation express orexin-1 and adrenergic alpha2A receptor mRNA. Neurosci Lett 2009; 459:115-8. [PMID: 19427365 DOI: 10.1016/j.neulet.2009.05.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 05/02/2009] [Accepted: 05/05/2009] [Indexed: 01/13/2023]
Abstract
Neurons located in the dorsomedial pontine rapid eye movement (REM) sleep-triggering region send axons to the medial medullary reticular formation (mMRF). This pathway is believed to be important for the generation of REM sleep motor atonia, but other than that they are glutamatergic little is known about neurochemical signatures of these pontine neurons important for REM sleep. We used single-cell reverse transcription and polymerase chain reaction (RT-PCR) to determine whether dorsomedial pontine cells with projections to the mMRF express mRNA for selected membrane receptors that mediate modulatory influences on REM sleep. Fluorescein (FITC)-labeled latex microspheres were microinjected into the mMRF of 26-34-day-old rats under pentobarbital anesthesia. After 5-6 days, rats were sacrificed, pontine slices were obtained and neurons were dissociated from 400 to 600 microm micropunches extracted from dorsomedial pontine reticular formation. We found that 32 out of 51 FITC-labeled cells tested (63+/-7% (SE)) contained the orexin type 1 receptor (ORX1r) mRNA, 27 out of 73 (37+/-6%) contained the adrenergic alpha(2A) receptor (alpha(2A)r) RNA, and 6 out of 31 (19+/-7%) contained both mRNAs. The percentage of cells positive for the ORX1r mRNA was significantly lower (p<0.04) for the dorsomedial pontine cells that were not retrogradely labeled from the mMRF (32+/-11%), whereas alpha(2A)r mRNA was present in a similar percentage of FITC-labeled and unlabeled neurons. Our data suggest that ORX and adrenergic pathways converge on a subpopulation of cells of the pontine REM sleep-triggering region that have descending projections to the medullary region important for the motor control during REM sleep.
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Affiliation(s)
- Denys V Volgin
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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