51
|
Clinton JM, Davis CJ, Zielinski MR, Jewett KA, Krueger JM. Biochemical regulation of sleep and sleep biomarkers. J Clin Sleep Med 2012; 7:S38-42. [PMID: 22003330 DOI: 10.5664/jcsm.1360] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Symptoms commonly associated with sleep loss and chronic inflammation include sleepiness, fatigue, poor cognition, enhanced sensitivity to pain and kindling stimuli, excess sleep and increases in circulating levels of tumor necrosis factor α (TNF) in humans and brain levels of interleukin-1 β (IL1) and TNF in animals. Cytokines including IL1 and TNF partake in non-rapid eye movement sleep (NREMS) regulation under physiological and inflammatory conditions. Administration of exogenous IL1 or TNF mimics the accumulation of these cytokines occurring during sleep loss to the extent that it induces the aforementioned symptoms. Extracellular ATP associated with neuro- and glio-transmission, acting via purine type 2 receptors, e.g., the P2X7 receptor, has a role in glia release of IL1 and TNF. These substances in turn act on neurons to change their intrinsic membrane properties and sensitivities to neurotransmitters and neuromodulators such as adenosine, glutamate and GABA. These actions change the network input-output properties, i.e., a state shift for the network. State oscillations occur locally within cortical columns and are defined using evoked response potentials. One such state, so defined, shares properties with whole animal sleep in that it is dependent on prior cellular activity--it shows homeostasis. The cortical column sleep-like state is induced by TNF and is associated with experimental performance detriments. ATP released extracellularly as a consequence of cellular activity is posited to initiate a mechanism by which the brain tracks its prior sleep-state history to induce/prohibit sleep. Thus, sleep is an emergent property of populations of local neural networks undergoing state transitions. Specific neuronal groups participating in sleep depend upon prior network use driving local network state changes via the ATP-cytokine-adenosine mechanism. Such considerations add complexity to finding biochemical markers for sleepiness.
Collapse
Affiliation(s)
- James M Clinton
- Sleep and Performance Research Center, WWAMI Medical Education Program, WA State University, Spokane, WA 99164, USA.
| | | | | | | | | |
Collapse
|
52
|
Jewett KA, Krueger JM. Humoral sleep regulation; interleukin-1 and tumor necrosis factor. VITAMINS AND HORMONES 2012; 89:241-57. [PMID: 22640617 PMCID: PMC4030541 DOI: 10.1016/b978-0-12-394623-2.00013-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Two substances, the cytokines interleukin-1 beta (IL1β) and tumor necrosis factor alpha (TNFα), known for their many physiological roles, for example, cognition, synaptic plasticity, and immune function, are also well characterized in their actions of sleep regulation. These substances promote non-rapid eye movement sleep and can induce symptoms associated with sleep loss such as sleepiness, fatigue, and poor cognition. IL1β and TNFα are released from glia in response to extracellular ATP. They bind to their receptors on neurons resulting in neuromodulator and neurotransmitter receptor up/downregulation (e.g., adenosine and glutamate receptors) leading to altered neuronal excitability and function, that is, a state change in the local network. Synchronization of state between local networks leads to emergent whole brain oscillations, such as sleep/wake cycles.
Collapse
Affiliation(s)
- Kathryn A Jewett
- WWAMI Medical Education Program, Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA
| | | |
Collapse
|
53
|
Krueger JM. TRANSLATION OF BRAIN ACTIVITY INTO SLEEP. HIROSAKI IGAKU = HIROSAKI MEDICAL JOURNAL 2012; 63:S1-S16. [PMID: 24795496 PMCID: PMC4007690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Cytokines including tumor necrosis factor alpha (TNF) play a role in sleep regulation in health and disease. Hypothalamic and cerebral cortical levels of TNF mRNA or TNF protein have diurnal variations with higher levels associated with greater sleep propensity. Sleep loss is associated with enhanced brain TNF. Central or systemic TNF injections enhance sleep. Inhibition of TNF using the soluble TNF receptor, or anti-TNF antibodies, or a TNF siRNA reduces spontaneous sleep. Mice lacking the TNF 55 kD receptor have less spontaneous sleep. Injection of TNF into sleep regulatory circuits, e.g. the hypothalamus, promotes sleep. In normal humans, plasma levels of TNF co-vary with EEG slow wave activity (SWA) and in multiple disease states plasma TNF increases in parallel with sleep propensity. Downstream mechanisms of TNF-enhanced sleep include nitric oxide, adenosine, prostaglandins and activation of nuclear factor kappa B. Neuronal use induces cortical neurons to express TNF and if applied directly to cortical columns TNF induces a functional sleep-like state within the column. TNF mechanistically has several synaptic functions. TNF-sleep data led to the idea that sleep is a fundamental property of neuronal/glial networks such as cortical columns and is dependent upon past activity within such assemblies. This view of brain organization of sleep has profound implications for sleep function that are briefly reviewed herein.
Collapse
Affiliation(s)
- James M. Krueger
- WWAMI Medical Education Program; Sleep and Performance Research Center, Washington State University, Spokane, WA 99210-1495, Fax 509-358-7882
| |
Collapse
|
54
|
Davis CJ, Clinton JM, Taishi P, Bohnet SG, Honn KA, Krueger JM. MicroRNA 132 alters sleep and varies with time in brain. J Appl Physiol (1985) 2011; 111:665-72. [PMID: 21719725 DOI: 10.1152/japplphysiol.00517.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
MicroRNA (miRNA) levels in brain are altered by sleep deprivation; however, the direct effects of any miRNA on sleep have not heretofore been described. We report herein that intracerebroventricular application of a miRNA-132 mimetic (preMIR-132) decreased duration of non-rapid-eye-movement sleep (NREMS) while simultaneously increasing duration of rapid eye movement sleep (REMS) during the light phase. Further, preMIR-132 decreased electroencephalographic (EEG) slow-wave activity (SWA) during NREMS, an index of sleep intensity. In separate experiments unilateral supracortical application of preMIR-132 ipsilaterally decreased EEG SWA during NREMS but did not alter global sleep duration. In addition, after ventricular or supracortical injections of preMIR-132, the mimetic-induced effects were state specific, occurring only during NREMS. After local supracortical injections of the mimetic, cortical miRNA-132 levels were higher at the time sleep-related EEG effects were manifest. We also report that spontaneous cortical levels of miRNA-132 were lower at the end of the sleep-dominant light period compared with at the end of the dark period in rats. Results suggest that miRNAs play a regulatory role in sleep and provide a new tool for investigating sleep regulation.
Collapse
Affiliation(s)
- Christopher J Davis
- Washington State University-Spokane, Health Sciences Bldg. 280E, 412 E Spokane Falls Blvd., Spokane, WA 99202, USA.
| | | | | | | | | | | |
Collapse
|
55
|
Cearley CN, Blindheim K, Sorg BA, Krueger JM, Churchill L. Acute cocaine increases interleukin-1β mRNA and immunoreactive cells in the cortex and nucleus accumbens. Neurochem Res 2011; 36:686-92. [PMID: 21399909 DOI: 10.1007/s11064-011-0410-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
The cytokine, interleukin-1β (IL1β) is a sleep regulatory substance whose expression is enhanced in response to neuronal stimulation. In this study, IL1β mRNA and immunoreactivity (IR) are evaluated after acute cocaine. First, IL1β mRNA levels were measured at the start or end of the light period after saline or acute exposure to a low dose of cocaine (5 mg/kg, intraperitoneal (ip)). IL1β mRNA levels after an acute exposure to cocaine (5 mg/kg, ip) at dark onset were significantly higher than those obtained from rats sacrificed after an acute exposure to saline in the piriform and somatosensory cortex, and nucleus accumbens. Acute exposure of cocaine at 5 mg/kg at dark onset also increased the number of IL1β-immunoreactive astrocytes in layer I-V of the prefrontal cortex, somatosensory cortex and nucleus accumbens. These data suggest that IL1β mRNA and protein levels in some of the dopaminergically innervated brain regions are responsive to cocaine.
Collapse
|
56
|
SENGUPTA P, ROY S, KRUEGER JM. The ATP-cytokine-adenosine hypothesis: How the brain translates past activity into sleep. Sleep Biol Rhythms 2011. [DOI: 10.1111/j.1479-8425.2010.00463.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
57
|
Abstract
PURPOSE OF REVIEW Regions of the neocortex most strongly activated during waking exhibit increased sleep intensity during subsequent sleep. The novel concept that aspects of sleep homeostasis are determined locally in the cortex contrasts with the established views that global changes in neocortical activity during sleep are achieved through inhibition of ascending arousal systems that originate in the brainstem and hypothalamus. RECENT FINDINGS Experiments in animals and humans document asymmetries in neocortical electroencephalogram (EEG) slow-wave activity (SWA), a marker of homeostatic sleep need, as a result of functional activity during waking. In addition to local, use-dependent augmentation of EEG SWA and evoked potentials, expression of plasticity-related genes and of sleep-regulatory cytokines and neuromodulators have been shown to be elevated in a use-dependent manner in neocortex. The functional consequences of local sleep are hypothesized to involve regulation of synaptic plasticity, synaptic homeostasis and energy balance. SUMMARY The evidence for use-dependent modulation of neocortical activity during sleep is compelling and provides novel insights into sleep function. However, local changes in neocortex are generally expressed on a background of global sleep. It remains to be determined if events initiated in the cortex have global sleep-promoting effects and how neocortical and hypothalamic mechanisms of sleep control interact.
Collapse
|
58
|
Krueger JM, Majde JA, Rector DM. Cytokines in immune function and sleep regulation. HANDBOOK OF CLINICAL NEUROLOGY 2011; 98:229-40. [PMID: 21056190 PMCID: PMC5440845 DOI: 10.1016/b978-0-444-52006-7.00015-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- James M Krueger
- Department of Veterinary and Comparetive Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520, USA.
| | | | | |
Collapse
|
59
|
Abstract
Many pro-inflammatory molecules, such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) are somnogenic, while many anti-inflammatory molecules inhibit sleep. Sleep loss increases the production/release of these sleep regulatory pro-inflammatory molecules. Further, sleep changes occurring during various pathologies are mediated by these inflammatory substances in response to pathogen recognition and subsequent inflammatory cellular pathways. This review summarizes information and concepts regarding inflammatory mechanisms of the innate immune system that mediate sleep. Further, we discuss sleep-immune interactions in regards to sleep in general, pathologies, and sleep as a local phenomenon including the central role that extracellular ATP plays in the initiation of sleep.
Collapse
Affiliation(s)
- Mark R Zielinski
- Sleep and Performance Research Center, Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520, USA
| | | |
Collapse
|
60
|
Krueger JM, Taishi P, De A, Davis CJ, Winters BD, Clinton J, Szentirmai E, Zielinski MR. ATP and the purine type 2 X7 receptor affect sleep. J Appl Physiol (1985) 2010; 109:1318-27. [PMID: 20829501 DOI: 10.1152/japplphysiol.00586.2010] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sleep is dependent upon prior brain activities, e.g., after prolonged wakefulness sleep rebound occurs. These effects are mediated, in part, by humoral sleep regulatory substances such as cytokines. However, the property of wakefulness activity that initiates production and release of such substances and thereby provides a signal for indexing prior waking activity is unknown. We propose that extracellular ATP, released during neuro- and gliotransmission and acting via purine type 2 (P2) receptors, is such a signal. ATP induces cytokine release from glia. Cytokines in turn affect sleep. We show here that a P2 receptor agonist, 2'(3')-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP), increased non-rapid eye movement sleep (NREMS) and electroencephalographic (EEG) delta power while two different P2 receptor antagonists, acting by different inhibitory mechanisms, reduced spontaneous NREMS in rats. Rat P2X7 receptor protein varied in the somatosensory cortex with time of day, and P2X7 mRNA was altered by interleukin-1 treatment, by sleep deprivation, and with time of day in the hypothalamus and somatosensory cortex. Mice lacking functional P2X7 receptors had attenuated NREMS and EEG delta power responses to sleep deprivation but not to interleukin-1 treatment compared with wild-type mice. Data are consistent with the hypothesis that extracellular ATP, released as a consequence of cell activity and acting via P2 receptors to release cytokines and other sleep regulatory substances, provides a mechanism by which the brain could monitor prior activity and translate it into sleep.
Collapse
Affiliation(s)
- James M Krueger
- Sleep and Performance Research Center, Programs in Neuroscience, Dept. of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520, USA.
| | | | | | | | | | | | | | | |
Collapse
|
61
|
Hallett H, Churchill L, Taishi P, De A, Krueger JM. Whisker stimulation increases expression of nerve growth factor- and interleukin-1beta-immunoreactivity in the rat somatosensory cortex. Brain Res 2010; 1333:48-56. [PMID: 20338152 PMCID: PMC2879054 DOI: 10.1016/j.brainres.2010.03.048] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 03/12/2010] [Accepted: 03/14/2010] [Indexed: 11/30/2022]
Abstract
Activity-dependent changes in cortical protein expression may mediate long-term physiological processes such as sleep and neural connectivity. In this study we determined the number of nerve growth factor (NGF)- and interleukin-1beta (IL1beta)-immunoreactive (IR) cells in the somatosensory cortex (Sctx) in response to 2 h of mystacial whisker stimulation. Manual whisker stimulation for 2 h increased the number of NGF-IR cells within layers II-V in activated Sctx columns, identified by enhanced Fos-IR. IL1beta-IR neurons increased within layers II-III and V-VI in these activated columns and IL1beta-IR astrocytes increased in layers I, II-III and V as well as the external capsule beneath the activated columns. These whisker-stimulated increases in the Sctx did not occur in the auditory cortex. These data demonstrate that expression of NGF or IL1beta in Sctx neurons and IL1beta in Sctx astrocytes is, in part, afferent input-dependent.
Collapse
Affiliation(s)
- Heather Hallett
- Dept. of Veterinary & Comparative Anatomy, Pharmacology and Physiology, Sleep and Performance Research Center, Program in Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520
- WWAMI Program at the University of Washington Medical School, Pullman, WA
| | - Lynn Churchill
- Dept. of Veterinary & Comparative Anatomy, Pharmacology and Physiology, Sleep and Performance Research Center, Program in Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520
| | - Ping Taishi
- Dept. of Veterinary & Comparative Anatomy, Pharmacology and Physiology, Sleep and Performance Research Center, Program in Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520
| | - Alok De
- Dept. of Veterinary & Comparative Anatomy, Pharmacology and Physiology, Sleep and Performance Research Center, Program in Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520
- Dept. of OB/Gyn, School of Medicine, *University of Missouri, Kansas City, Kansas City, Missouri 64108
| | - James M. Krueger
- Dept. of Veterinary & Comparative Anatomy, Pharmacology and Physiology, Sleep and Performance Research Center, Program in Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520
| |
Collapse
|
62
|
Time of day differences in the number of cytokine-, neurotrophin- and NeuN-immunoreactive cells in the rat somatosensory or visual cortex. Brain Res 2010; 1337:32-40. [PMID: 20398636 DOI: 10.1016/j.brainres.2010.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 03/31/2010] [Accepted: 04/07/2010] [Indexed: 12/22/2022]
Abstract
Sensory input to different cortical areas differentially varies across the light-dark cycle and likely is responsible, in part, for activity-dependent changes in time-of-day differences in protein expression such as Fos. In this study we investigate time-of-day differences between dark (just before light onset) and light (just before dark onset) for the number of immunoreactive (IR) neurons that stained for tumor necrosis factor alpha (TNFalpha), interleukin-1 beta (IL1 beta), nerve growth factor (NGF), the neuronal nuclear protein (NeuN) and Fos in the rat somatosensory cortex (Sctx) and visual cortex (Vctx). Additionally, astrocyte IL1 beta-IR in the Sctx and Vctx was determined. TNFalpha and IL1 beta, as well as the immediate early gene protein Fos, were higher at the end of the dark phase (2300 h) compared to values obtained at the end of the light phase (1100 h) in the Sctx and Vctx. IL1 beta-IR in Sctx and Vctx astrocytes was higher at 2300 h than that observed at 1100 h. . In contrast, the number of NGF-IR neurons was higher in the Vctx than in the Sctx but did not differ in time. However, the density of the NGF-IR neurons in layer V was greater at 2300 h in the Sctx than at 1100 h. NeuN-IR was higher at 2300 h in the Sctx but was lower at this time in the Vctx compared to 1100 h. These data demonstrate that expressions of the molecules examined are dependent on activity, the sleep-wake cycle and brain location. These factors interact to modulate time-of-day expression.
Collapse
|
63
|
Goodman AOG, Barker RA. How vital is sleep in Huntington’s disease? J Neurol 2010; 257:882-97. [DOI: 10.1007/s00415-010-5517-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 02/15/2010] [Accepted: 02/25/2010] [Indexed: 01/21/2023]
|
64
|
Schwartz AR, Patil SP, Squier S, Schneider H, Kirkness JP, Smith PL. Obesity and upper airway control during sleep. J Appl Physiol (1985) 2009; 108:430-5. [PMID: 19875707 DOI: 10.1152/japplphysiol.00919.2009] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mechanisms linking obesity with upper airway dysfunction in obstructive sleep apnea are reviewed. Obstructive sleep apnea is due to alterations in upper airway anatomy and neuromuscular control. Upper airway structural alterations in obesity are related to adipose deposition around the pharynx, which can increase its collapsibility or critical pressure (P(crit)). In addition, obesity and, particularly, central adiposity lead to reductions in resting lung volume, resulting in loss of caudal traction on upper airway structures and parallel increases in pharyngeal collapsibility. Metabolic and humoral factors that promote central adiposity may contribute to these alterations in upper airway mechanical function and increase sleep apnea susceptibility. In contrast, neural responses to upper airway obstruction can mitigate these mechanical loads and restore pharyngeal patency during sleep. Current evidence suggests that these responses can improve with weight loss. Improvements in these neural responses with weight loss may be related to a decline in systemic and local pharyngeal concentrations of specific inflammatory mediators with somnogenic effects.
Collapse
Affiliation(s)
- Alan R Schwartz
- Sleep Disorders Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21224, USA.
| | | | | | | | | | | |
Collapse
|
65
|
A potential role for pro-inflammatory cytokines in regulating synaptic plasticity in major depressive disorder. Int J Neuropsychopharmacol 2009; 12:561-78. [PMID: 19224657 PMCID: PMC2771334 DOI: 10.1017/s1461145709009924] [Citation(s) in RCA: 230] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A growing body of data suggests that hyperactivation of the immune system has been implicated in the pathophysiology of major depressive disorder (MDD). Several pro-inflammatory cytokines, such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) have been found to be significantly increased in patients with MDD. This review focuses on these two cytokines based on multiple lines of evidence from genetic, animal behaviour, and clinical studies showing that altered levels of serum TNF-alpha and IL-1 are associated with increased risk of depression, cognitive impairments, and reduced responsiveness to treatment. In addition, recent findings have shown that centrally expressed TNF-alpha and IL-1 play a dual role in the regulation of synaptic plasticity. In this paper, we review and critically appraise the mechanisms by which cytokines regulate synaptic and neural plasticity, and their implications for the pathophysiology and treatment of MDD. Finally, we discuss the therapeutic potential of anti-inflammatory-based approaches for treating patients with severe mood disorders. This is a promising field for increasing our understanding of the mechanistic interaction between the immune system, synaptic plasticity, and antidepressants, and for the ultimate development of novel and improved therapeutics for severe mood disorders.
Collapse
|
66
|
|
67
|
Rector DM, Schei JL, Van Dongen HPA, Belenky G, Krueger JM. Physiological markers of local sleep. Eur J Neurosci 2009; 29:1771-8. [PMID: 19473232 DOI: 10.1111/j.1460-9568.2009.06717.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Substantial evidence suggests that brain regions that have been disproportionately used during waking will require a greater intensity and/or duration of subsequent sleep. For example, rats use their whiskers in the dark and their eyes during the light, and this is manifested as a greater magnitude of electroencephalogram (EEG) slow-wave activity in the somatosensory and visual cortex during sleep in the corresponding light and dark periods respectively. The parsimonious interpretation of such findings is that sleep is distributed across local brain regions and is use-dependent. The fundamental properties of sleep can also be experimentally defined locally at the level of small neural assemblies such as cortical columns. In this view, sleep is orchestrated, but not fundamentally driven, by central mechanisms. We explore two physiological markers of local, use-dependent sleep, namely, an electrical marker apparent as a change in the size and shape of an electrical evoked response, and a metabolic marker evident as an evoked change in blood volume and oxygenation delivered to activated tissue. Both markers, applied to cortical columns, provide a means to investigate physiological mechanisms for the distributed homeostatic regulation of sleep, and may yield new insights into the consequences of sleep loss and sleep pathologies on waking brain function.
Collapse
Affiliation(s)
- David M Rector
- Sleep and Performance Research Center and Program in Neuroscience, Washington State University, Spokane, WA 99210-1495, USA.
| | | | | | | | | |
Collapse
|
68
|
Abstract
Sleep need is affected by developmental stage and neuronal plasticity, but the underlying mechanisms remain unclear. The fragile X mental retardation gene Fmr1, whose loss-of-function mutation causes the most common form of inherited mental retardation in humans, is involved in synaptogenesis and synaptic plasticity, and its expression depends on both developmental stage and waking experience. Fmr1 is highly conserved across species and Drosophila mutants carrying dFmr1 loss-of-function or gain-of-function mutations are well characterized: amorphs have overgrown dendritic trees with larger synaptic boutons, developmental defects in pruning, and enhanced neurotransmission, while hypermorphs show opposite defects, including dendritic and axonal underbranching and loss of synapse differentiation. We find here that dFmr1 amorphs are long sleepers and hypermorphs are short sleepers, while both show increased locomotor activity and shortened lifespan. Both amorphs and hypermorphs also show abnormal sleep homeostasis, with impaired waking performance and no sleep rebound after sleep deprivation. An impairment in the circadian regulation of sleep cannot account for the altered sleep phenotype of dFmr1 mutants, nor can an abnormal activation of glutamatergic metabotropic receptors. Moreover, overexpression of dFmr1 throughout the mushroom bodies is sufficient to reduce sleep. Finally, dFmr1 protein levels are modulated by both developmental stage and behavioral state, with increased expression immediately after eclosure and after prolonged wakefulness. Thus, dFmr1 expression dose-dependently affects both sleep and synapses, suggesting that changes in sleep time in dFmr1 mutants may derive from changes in synaptic physiology.
Collapse
|
69
|
Krueger JM, Rector DM, Roy S, Van Dongen HPA, Belenky G, Panksepp J. Sleep as a fundamental property of neuronal assemblies. Nat Rev Neurosci 2008; 9:910-9. [PMID: 18985047 PMCID: PMC2586424 DOI: 10.1038/nrn2521] [Citation(s) in RCA: 365] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sleep is vital to cognitive performance, productivity, health and well-being. Earlier theories of sleep presumed that it occurred at the level of the whole organism and that it was governed by central control mechanisms. However, evidence now indicates that sleep might be regulated at a more local level in the brain: it seems to be a fundamental property of neuronal networks and is dependent on prior activity in each network. Such local-network sleep might be initiated by metabolically driven changes in the production of sleep-regulatory substances. We discuss a mathematical model which illustrates that the sleep-like states of individual cortical columns can be synchronized through humoral and electrical connections, and that whole-organism sleep occurs as an emergent property of local-network interactions.
Collapse
Affiliation(s)
- James M Krueger
- Department of VCAPP, College of Veterinary Medicine, Washington State University, PO BOX 646520, Pullman, Washington 99164-6520, USA.
| | | | | | | | | | | |
Collapse
|