检索问题
8小时睡眠其实是工业时代的产物，为了集中生产时间。实际上人的本能就是睡睡醒醒，和猫一样。 这种说法对么？
这种说法是不准确的。虽然“必须睡满8小时”这个绝对的数字可能带有现代社会的标准色彩，但人类“集中在夜晚进行长时间睡眠”的模式并非工业时代的产物，而是刻写在我们基因里的生物本能。科学证据表明，人类是拥有大约24小时昼夜节律的生物，如果像猫一样“碎片化”地睡睡醒醒，不仅不符合天性，反而是身体出大问题的信号。
以下是基于科学证据的详细解释：
1. 我们的身体里有一个“总指挥”，要求我们按天过日子
人类并不是随便什么时候想睡就能睡好的生物。我们的身体里有一套非常精密的“生物钟”系统，它的运作周期大约是24小时，这跟地球自转、白天黑夜的交替是完全对应的。
- 大脑里的总司令：在大脑深处有一个叫“视交叉上核”（SCN）的部位，它是我们身体的主时钟。它接收眼睛看到的关线信号（白天还是黑夜），然后指挥全身的器官——什么时候该吃饭、什么时候体温该升高、什么时候该分泌激素。
- 基因的铁律：这种节律不仅仅是在大脑里，它甚至存在于我们将近所有的细胞中。科学家已经发现了专门控制这种节律的“时钟基因”（比如 Clock、BMal1 等）。这些基因就像一个个微小的计时器，在细菌、果蝇到人类身上都存在。
- 结论：这意味着，人类演化了几百万年，就是为了适应“日出而作，日入而息”的地球环境。工业革命才几百年历史，不可能改变这种千万年形成的基因本能。
2. 像猫一样“睡睡醒醒”其实是生病的表现
猫是捕食者，且多在晨昏活动，它们的睡眠确实是多阶段的。但对人类来说，如果睡眠变得像猫一样支离破碎（科学上叫“睡眠片段化”），通常不是“返璞归真”，而是大脑受损或代谢紊乱的征兆。
- 老年痴呆的信号：研究发现，患有阿尔茨海默病（老年痴呆症）的病人，最典型的症状之一就是生物钟被打碎了。他们不再有明显的昼夜之分，白天打瞌睡，晚上睡不着，睡眠变得非常零碎。这说明“睡睡醒醒”是大脑功能退化的表现，而不是健康的常态。
- 甚至是攻击性的来源：有研究指出，那种甚至无法维持正常睡眠觉醒周期的情况（比如注意力缺陷多动障碍 ADHD 患者），往往伴随着攻击性行为和情绪问题，这与生物钟基因的异常有关。
3. 强行打破“集中睡眠”会带来严重疾病
如果人类真的像猫一样生活，违背了体内24小时的自然节律，身体的代谢系统会迅速崩溃。
- 肥胖和糖尿病：当我们体内的时钟（生物钟）和外部的时间（比如该睡觉的时候在吃东西或工作）对不上号时，就会发生“生物钟失调”。现在的倒班工作者就是典型的例子。证据显示，这种失调会直接导致肥胖、糖尿病和脂肪肝。
- 代谢综合征：有研究明确指出，为了避免代谢综合征（这是一种包括高血压、高血糖、腰围过粗在内的危险状态），人类最佳的睡眠时长确实是在7到8小时之间。睡眠时间过短或睡眠质量支离破碎，都是明确的致病风险因素。
- 免疫力下降：我们的免疫系统也有自己的生物钟。如果像猫一样乱睡，打破了这个节奏，感染疾病的风险就会增加，甚至会影响DNA修复，增加患癌风险。
4. 所谓的“8小时”是怎么回事？
虽然“8小时”是一个平均后的统计数字，但它背后的生理需求是真实的。
- 睡眠结构：正常成年人的睡眠是一个连续的过程，包括浅睡、深睡和做梦（快速眼动睡眠 REM）的循环。这一整套流程要在晚上连续进行大约24小时为一个周期。如果把它打散成一天睡很多次，每次睡一小会儿，身体就无法完整地完成修复大脑和身体的任务。
- 光照的作用：光线是调节我们生物钟最强的信号。工业时代虽然有了电灯，但这反而是干扰了我们的自然睡眠，让我们睡得更晚、更少，而不是创造了“集中睡眠”。恰恰相反，是工业时代的灯光让我们更容易像猫一样不分昼夜地活动，从而伤害了健康。
总结来说： 人类是昼行性动物，我们的出厂设置就是“白天活动，夜晚集中休息”。虽然不需要每个人都分秒不差地睡满8小时（有的人可能需要9小时，有的人7小时够了），但“整段的夜间睡眠”是保护大脑、维持代谢正常和预防疾病的关键。像猫一样碎片化的睡眠，对人类来说是病态的，千万不要模仿。
References
1Circadian rhythms, sleep, and metabolism.PubMed
Wenyu Huang, Kathryn Moynihan Ramsey, Biliana Marcheva, et al.
J Clin Invest. 2011 Jun;121(6):2133-41. doi: 10.1172/JCI46043. Epub 2011 Jun 1.
The discovery of the genetic basis for circadian rhythms has expanded our knowledge of the temporal organization of behavior and physiology. The observations that the circadian gene network is present in most living organisms from eubacteria to humans, that most cells and tissues express autonomous clocks, and that disruption of clock genes results in metabolic dysregulation have revealed interactions between metabolism and circadian rhythms at neural, molecular, and cellular levels. A major challenge remains in understanding the interplay between brain and peripheral clocks and in determining how these interactions promote energy homeostasis across the sleep-wake cycle. In this Review, we evaluate how investigation of molecular timing may create new opportunities to understand and develop therapies for obesity and diabetes.
2Circadian integration of metabolism and energetics.PubMed
Joseph Bass, Joseph S Takahashi
Science. 2010 Dec 3;330(6009):1349-54. doi: 10.1126/science.1195027.
Circadian clocks align behavioral and biochemical processes with the day/night cycle. Nearly all vertebrate cells possess self-sustained clocks that couple endogenous rhythms with changes in cellular environment. Genetic disruption of clock genes in mice perturbs metabolic functions of specific tissues at distinct phases of the sleep/wake cycle. Circadian desynchrony, a characteristic of shift work and sleep disruption in humans, also leads to metabolic pathologies. Here, we review advances in understanding the interrelationship among circadian disruption, sleep deprivation, obesity, and diabetes and implications for rational therapeutics for these conditions.
3Circadian Rhythm Sleep-Wake Disorders: a Contemporary Review of Neurobiology, Treatment, and Dysregulation in Neurodegenerative Disease.PubMed
Tyler A Steele, Erik K St Louis, Aleksandar Videnovic, et al.
Neurotherapeutics. 2021 Jan;18(1):53-74. doi: 10.1007/s13311-021-01031-8. Epub 2021 Apr 12.
Circadian rhythms oscillate throughout a 24-h period and impact many physiological processes and aspects of daily life, including feeding behaviors, regulation of the sleep-wake cycle, and metabolic homeostasis. Misalignment between the endogenous biological clock and exogenous light-dark cycle can cause significant distress and dysfunction, and treatment aims for resynchronization with the external clock and environment. This article begins with a brief historical context of progress in the understanding of circadian rhythms, and then provides an overview of circadian neurobiology and the endogenous molecular clock. Various tools used in the diagnosis of circadian rhythm sleep-wake disorders, including sleep diaries and actigraphy monitoring, are then discussed, as are the therapeutic applications of strategically timed light therapy, melatonin, and other behavioral and pharmacological therapies including the melatonin agonist tasimelteon. Management strategies towards each major human circadian sleep-wake rhythm disorder, as outlined in the current International Classification of Sleep Disorders - Third Edition, including jet lag and shift work disorders, delayed and advanced sleep-wake phase rhythm disorders, non-24-h sleep-wake rhythm disorder, and irregular sleep-wake rhythm disorder are summarized. Last, an overview of chronotherapies and the circadian dysregulation of neurodegenerative diseases is reviewed.
4Clock-Sleep Communication.PubMed
Seithikurippu R Pandi-Perumal, Sayan Paul, Konda Mani Saravanan, et al.
Curr Mol Med. 2025;25(4):399-415. doi: 10.2174/0115665240305615240630113434.
Rhythmicity is a characteristic feature of the inanimate universe. The organization of biological rhythms in time is an adaptation to the cyclical environmental changes brought on by the earth's rotation on its axis and around the sun. Circadian (L. Circa = "around or approximately"; diem = "a day") rhythms are biological responses to the geophysical light/dark (LD) cycle in which an organism adjusts to alterations in its internal physiology or external environment as a function of the time of day. Sleep has been considered a biological rhythm. Normal human sleep, an essential physiologic process, comprises two distinct phases: non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. A mature adult human's sleep/wake cycle displays a circadian rhythm with a ~24-hour cycle. According to the two-process model of sleep regulation, the human sleep/wake cycle is orchestrated by circadian and homeostatic processes. Sleep homeostasis (a sleep-dependent process) and circadian rhythm (a sleep-independent process) are two biological processes controlling the sleep/wake cycle. There are also ultradian (< 24-hour) rhythms, including the NREM-REM sleep cycle, which has been extensively studied. The clock and sleep genes both influence sleep. In this overview, we have reviewed the circadian genes and their role in regulating sleep. Besides, the gene expression and biological pathways associated with sleep and circadian rhythm-associated diseases also have been highlighted.
5Clinical Chronobiology: Circadian Rhythms in Health and Disease.PubMed
Shizuka Tomatsu, Sabra M Abbott, Hrayr Attarian
Semin Neurol. 2025 May;45(3):317-332. doi: 10.1055/a-2538-3259. Epub 2025 Feb 17.
Circadian rhythms (CRs) are entrainable endogenous rhythms that respond to external stimuli and regulate physiological functions. The suprachiasmatic nucleus (SCN) in the hypothalamus is the mammalian master clock that synchronizes all other tissue-specific peripheral clocks, primarily through gamma-aminobutyric acid (GABA) and vasoactive intestinal polypeptide (VIP). The SCN follows Earth's 24-hour cycle by light entrainment through the retinohypothalamic tract. At the cellular level, the core clock genes , , , , and regulate CRs in a negative feedback loop. The circadian disruption of the sleep-wake cycle manifests in at least six distinct clinical conditions. These are the circadian rhythm sleep-wake disorders (CRSWDs). Their diagnosis is made by history, sleep diaries, and actigraphy. Treatment involves a combination of timed light exposure, melatonin/melatonin agonists, and behavioral interventions. In addition, CR disturbances and subsequent misalignment can increase the risk of a variety of illnesses. These include infertility and menstrual irregularities as well as diabetes, obesity, fatty liver disease, and other metabolic syndromes. In addition, a disruption in the gut microbiome creates a proinflammatory environment. CR disturbances increase the risk for mood disorders, hence the utility of light-based therapies in depression. People with neurodegenerative disorders demonstrate significant disturbances in their CRs, and in their sleep-wake cycles. Circadian realignment therapies can also help decrease the symptomatic burden of these disorders. Certain epilepsy syndromes, such as juvenile myoclonic epilepsy (JME), have a circadian pattern of seizures. Circadian disturbances in epilepsy can be both the consequence and cause for breakthrough seizures. The immune system has its own CR. Disturbances in these due to shift work, for instance, can increase the risk of infections. CR disturbances can also increase the risk of cancer by impacting DNA repair, apoptosis, immune surveillance, and cell cycle regulation. Moreover, the timing of chemotherapeutic agents has been shown to increase their therapeutic impact in certain cancers.
6Biological clocks.PubMed
N Ishida, M Kaneko, R Allada
Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8819-20. doi: 10.1073/pnas.96.16.8819.
Circadian rhythms describe biological phenomena that oscillate with an approximately 24-hour cycle. These rhythms include blood pressure, body temperature, hormone levels, the number of immune cells in blood, and the sleep-wake cycle. In this paper, we will focus on common genes between species that are responsible for determining the circadian behavior, especially some transcription factors (i.e., switch genes) that serve to regulate many circadian rhythm genes. The intent of this summary is to introduce the common molecular mechanism of biological clocks between flies and humans and then to describe the research from three laboratories that was presented in the session.
7Circadian Rhythm Sleep-Wake Disorders.PubMed
Sabra M Abbott, Kathryn J Reid, Phyllis C Zee
Psychiatr Clin North Am. 2015 Dec;38(4):805-23. doi: 10.1016/j.psc.2015.07.012. Epub 2015 Sep 1.
The circadian system regulates the timing and expression of nearly all biological processes, most notably, the sleep-wake cycle, and disruption of this system can result in adverse effects on both physical and mental health. The circadian rhythm sleep-wake disorders (CRSWDs) consist of 5 disorders that are due primarily to pathology of the circadian clock or to a misalignment of the timing of the endogenous circadian rhythm with the environment. This article outlines the nature of these disorders, the association of many of these disorders with psychiatric illness, and available treatment options.
8Voluntary wheel running exercise improves sleep disorder, circadian rhythm disturbance, and neuropathology in an animal model of Alzheimer's disease.PubMed
Yiying Hu, Long Niu, Yixin Chen, et al.
Alzheimers Dement. 2025 Jun;21(6):e70314. doi: 10.1002/alz.70314.
INTRODUCTION: The sleep-wake cycle and circadian rhythm disturbances are common in Alzheimer's disease (AD). However, it is not known if exercise has any benefit for the sleep disorders in AD. METHODS: We conducted a 2-month voluntary wheel running (VWR) exercise (Ex) in an animal model of AD (APP/PS1 mice). We assessed behavioral circadian rhythm, sleep structure, circadian clock genes, cognitive function, and neurodegeneration in the suprachiasmatic nucleus (SCN), the hippocampus, and the cortex. RESULTS: After VWR exercise in the AD mice, the rapid eye movement sleep was increased by 89%. The levels of circadian clock genes were significantly changed (brain and muscle arnt-like protein 1 [BMAL1] and retinoic acid receptor-related orphan receptorsα [RORα] reduced by 45.7% and 36.4%, reverse erythroblastosis virusα (REV-ERBα) increased by 119%) in the SCN by immunofluorescence staining, with the mRNA levels were markedly altered (Bmal1 and Rorα decreased by 57% and 68%, Rev-erbα elevated by 79%) in the hypothalamus at Zeitgeber Time 1; phospho-tau 231 (p-tau231) was reduced by 35%, whereas vesicular GABA transporter (VGAT) was elevated by 38.7% in the SCN. In addition, ionized calcium binding adapter molecude 1 (Iba1), glial fibrillary acidic protein (GFAP), amyloid β (Aβ), and p-tau231 were significantly reduced in the hippocampus and cortex. DISCUSSION: Our results demonstrate that VWR exercise improves sleep disorders, cognitive deficits, and neuropathology in AD mice. HIGHLIGHTS: Voluntary wheel running (VWR) exercise improves the behavioral circadian rhythm disorder and sleep structure disturbance in Alzheimer's disease (AD) mice. After VWR exercise, there is a significant change in the expression levels of circadian clock genes, and a remarkable reduction of tau phosphorylation and axonal damage in the γ-aminobutyric acid (GABA)ergic neurons in the suprachiasmatic nucleus (SCN). The levels of beta-site amyloid precurson protein cleaving enzyme 1 (BACE1) and glycogen synthase kinase-3β (GSK3β) are reduced in the hypothalamus after VWR exercise in AD mice. Furthermore, VWR exercise attenuates cognitive deficits, neuroinflammation, amyloid beta (Aβ), and phospho-tau protein accumulation in the hippocampus and cortex.
9Clock genes, ADHD and aggression.PubMed
Floriana Mogavero, Amanda Jager, Jeffrey C Glennon
Neurosci Biobehav Rev. 2018 Aug;91:51-68. doi: 10.1016/j.neubiorev.2016.11.002. Epub 2016 Nov 9.
Attention deficit/hyperactivity disorder (ADHD) is frequently associated with comorbid aggression and sleep disturbances. The sleep/wake cycle is under the control of the circadian system which is moderated by clock genes. Clock genes can regulate the transcription of monoamine oxidase A, which is involved in the degradation of monoamines. Disturbances in monoamine interaction with clock genes in those with monoamine gene polymorphisms may regulate susceptibility of ADHD and comorbid aggression/sleep disturbances. While monoamines influence circadian rhythm and clock gene expression, circadian rhythm components modulate aggressive behavior, and altered clock genes expression have been associated with ADHD. We propose a mechanism by which circadian rhythm and clock gene expression may influence ADHD and comorbid aggression through the modulation of neurotransmitters. The role of clock genes in ADHD patients with comorbid aggression awaits further research; therefore we also indicate directions for future studies to help increase understanding of the underlying mechanisms in ADHD with comorbid aggression and sleep disturbances.
10Circadian Clock Desynchronization and Insulin Resistance.PubMed
Federica Catalano, Francesca De Vito, Velia Cassano, et al.
Int J Environ Res Public Health. 2022 Dec 20;20(1):29. doi: 10.3390/ijerph20010029.
The circadian rhythm regulates biological processes that occur within 24 h in living organisms. It plays a fundamental role in maintaining biological functions and responds to several inputs, including food intake, light/dark cycle, sleep/wake cycle, and physical activity. The circadian timing system comprises a central clock located in the suprachiasmatic nucleus (SCN) and tissue-specific clocks in peripheral tissues. Several studies show that the desynchronization of central and peripheral clocks is associated with an increased incidence of insulin resistance (IR) and related diseases. In this review, we discuss the current knowledge of molecular and cellular mechanisms underlying the impact of circadian clock dysregulation on insulin action. We focus our attention on two possible mediators of this interaction: the phosphatases belonging to the pleckstrin homology leucine-rich repeat protein phosphatase family (PHLPP) family and the deacetylase Sirtuin1. We believe that literature data, herein summarized, suggest that a thorough change of life habits, with the return to synchronized food intake, physical activity, and rest, would doubtless halt the vicious cycle linking IR to dysregulated circadian rhythms. However, since such a comprehensive change may be incompatible with the demand of modern society, clarifying the pathways involved may, nonetheless, contribute to the identification of therapeutic targets that may be exploited to cure or prevent IR-related diseases.
11Circadian Disruption Associated with Alzheimer's Disease.PubMed
Yumna Saeed, Sabra M Abbott
Curr Neurol Neurosci Rep. 2017 Apr;17(4):29. doi: 10.1007/s11910-017-0745-y.
Alzheimer's disease (AD) is increasing in prevalence and has a significant impact on caregivers and the healthcare system. One of the many physiologic process affected by AD is the circadian system, with disruption reflected in abnormalities of the sleep-wake cycle. This interaction is bidirectional, with circadian and sleep disruption influencing disease progression. Understanding the bidirectional relationship between AD and circadian disruption may allow for earlier recognition of the potential to develop dementia as well as improved targeted approaches for therapy. Therapies including melatonin and bright light therapy may be advantageous in improving sleep and circadian rhythms and preventing the progression of disease. However, unfortunately, these modalities are not curative, and additional research is needed to improve treatment options for these individuals.
12[Psychiatry and circadian rhythms].PubMed
Klaus Martiny, Carlo Volf, Signe Dunker Svendsen, et al.
Ugeskr Laeger. 2018 Sep 3;180(36).
Circadian and seasonal rhythm disturbances are prominent in patients with psychiatric disorders. Properly timed and dosed light of specific spectral composition stabilises mood and sleep through serotonergic mechanisms and through input to the master circadian clock in the hypothalamus. Correctly administered, light can be used as an effective treatment for seasonal and non-seasonal depression and for stabilising the sleep-wake cycle. Blocking blue light in the evening may provide a non-pharmacological anti-manic tool. Current developments use dynamic lighting built into somatic and psychiatric hospitals to maximise the beneficial effects of light.
13Circadian molecular clocks and cancer.PubMed
Fergal C Kelleher, Aparna Rao, Anne Maguire
Cancer Lett. 2014 Jan 1;342(1):9-18. doi: 10.1016/j.canlet.2013.09.040. Epub 2013 Oct 4.
Physiological processes such as the sleep-wake cycle, metabolism and hormone secretion are controlled by a circadian rhythm adapted to 24h day-night periodicity. This circadian synchronisation is in part controlled by ambient light decreasing melatonin secretion by the pineal gland and co-ordinated by the suprachiasmatic nucleus of the hypothalamus. Peripheral cell autonomous circadian clocks controlled by the suprachiasmatic nucleus, the master regulator, exist within every cell of the body and are comprised of at least twelve genes. These include the basic helix-loop-helix/PAS domain containing transcription factors; Clock, BMal1 and Npas2 which activate transcription of the periodic genes (Per1 and Per2) and cryptochrome genes (Cry1 and Cry2). Points of coupling exist between the cellular clock and the cell cycle. Cell cycle genes which are affected by the molecular circadian clock include c-Myc, Wee1, cyclin D and p21. Therefore the rhythm of the circadian clock and cancer are interlinked. Molecular examples exist including activation of Per2 leads to c-myc overexpression and an increased tumor incidence. Mice with mutations in Cryptochrome 1 and 2 are arrhythmic (lack a circadian rhythm) and arrhythmic mice have a faster rate of growth of implanted tumors. Epidemiological finding of relevance include 'The Nurses' Health Study' where it was established that women working rotational night shifts have an increased incidence of breast cancer. Compounds that affect circadian rhythm exist with attendant future therapeutic possibilities. These include casein kinase I inhibitors and a candidate small molecule KL001 that affects the degradation of cryptochrome. Theoretically the cell cycle and malignant disease may be targeted vicariously by selective alteration of the cellular molecular clock.
14How does general anaesthesia affect the circadian clock?PubMed
Raewyn C Poulsen, Guy R Warman, Jamie Sleigh, et al.
Sleep Med Rev. 2018 Feb;37:35-44. doi: 10.1016/j.smrv.2016.12.002. Epub 2016 Dec 18.
UNLABELLED: Post-operative patients experience sleep disturbances. Animal studies demonstrate that general anaesthesia (GA) can disrupt circadian rhythms and cause changes in the molecular clock, indicating that anaesthesia contributes to post-operative circadian disruption. Here we review the effect of anaesthesia on the circadian clock and its rhythms in order to summarise current findings outline commonalities between studies and propose mechanisms by which effects may be mediated. KEY POINTS: 1) GA has strong effects on the main neurotransmitter systems linked with circadian control (Gamma aminobutyric acid/N-methyl-D-aspartate (GABA/NMDA)) and may act by interfering with light-entrainment of the clock. 2) Expression of the core clock gene per2 is inhibited by GA (possibly via a NMDA/glycogen synthase kinase 3β (GSK3β) pathway). 3) GA's effect on circadian rhythms appears greatest when administered during animals' active phases 4) GA may have different effects when administered under free-running and entrained conditions. 5) Anaesthesia may mimic the mechanism involved in adaptation of the clock to changes in daylength. There is agreement that GA can strongly affect the circadian clock. How anaesthesia-induced changes in the molecular clock lead to changes in behaviour remains unclear. The answer, and what it may mean for patients post-operatively, will rely on systematic studies at molecular, behavioural, and clinical levels using standardised protocols.
15Circadian clock desynchronisation and metabolic syndrome.PubMed
Mae Sheikh-Ali, Jaisri Maharaj
Postgrad Med J. 2014 Aug;90(1066):461-6. doi: 10.1136/postgradmedj-2013-132366. Epub 2014 Jun 23.
There is emerging evidence in the literature to suggest that disruption of the normal circadian rhythm (sleep-wake cycle signalling) is a potential risk factor to explain the increased incidence of metabolic syndrome. Over the last century, obesity, diabetes and other components of metabolic syndrome have been on the rise. On the other hand, the amount of sleep has decreased from an average of 6-8 h per night. Furthermore, the quality of sleep has declined with more individuals voluntarily decreasing their amount of sleep to work or enjoy leisure activities. Over the last decade, researchers have examined the relationship between disruption in human circadian system and the emergence of symptoms related to metabolic syndrome. Indeed, epidemiological studies suggest a relation between sleep duration and diabetes and obesity. Moreover, experimental animal and human studies suggest such a relation. These studies propose optimum sleep duration of 7-8 h per night to avoid circadian rhythm disruption and suggest that sleep disturbance, whether iatrogenic or disease-related, should be considered as a risk factor for metabolic syndrome, and be addressed. This field is in its infancy and further understanding of specific pathophysiological pathways of circadian desynchronisation will help in developing novel preventive and therapeutic strategies.
16The sleep-wake cycle and Alzheimer's disease: what do we know?PubMed
Miranda M Lim, Jason R Gerstner, David M Holtzman
Neurodegener Dis Manag. 2014;4(5):351-62. doi: 10.2217/nmt.14.33.
Sleep-wake disturbances are a highly prevalent and often disabling feature of Alzheimer's disease (AD). A cardinal feature of AD includes the formation of amyloid plaques, associated with the extracellular accumulation of the amyloid-β (Aβ) peptide. Evidence from animal and human studies suggests that Aβ pathology may disrupt the sleep-wake cycle, in that as Aβ accumulates, more sleep-wake fragmentation develops. Furthermore, recent research in animal and human studies suggests that the sleep-wake cycle itself may influence Alzheimer's disease onset and progression. Chronic sleep deprivation increases amyloid plaque deposition, and sleep extension results in fewer plaques in experimental models. In this review geared towards the practicing clinician, we discuss possible mechanisms underlying the reciprocal relationship between the sleep-wake cycle and AD pathology and behavior, and present current approaches to therapy for sleep disorders in AD.
17Circadian clocks, rhythmic synaptic plasticity and the sleep-wake cycle in zebrafish.PubMed
Idan Elbaz, Nicholas S Foulkes, Yoav Gothilf, et al.
Front Neural Circuits. 2013 Feb 1;7:9. doi: 10.3389/fncir.2013.00009. eCollection 2013.
The circadian clock and homeostatic processes are fundamental mechanisms that regulate sleep. Surprisingly, despite decades of research, we still do not know why we sleep. Intriguing hypotheses suggest that sleep regulates synaptic plasticity and consequently has a beneficial role in learning and memory. However, direct evidence is still limited and the molecular regulatory mechanisms remain unclear. The zebrafish provides a powerful vertebrate model system that enables simple genetic manipulation, imaging of neuronal circuits and synapses in living animals, and the monitoring of behavioral performance during day and night. Thus, the zebrafish has become an attractive model to study circadian and homeostatic processes that regulate sleep. Zebrafish clock- and sleep-related genes have been cloned, neuronal circuits that exhibit circadian rhythms of activity and synaptic plasticity have been studied, and rhythmic behavioral outputs have been characterized. Integration of this data could lead to a better understanding of sleep regulation. Here, we review the progress of circadian clock and sleep studies in zebrafish with special emphasis on the genetic and neuroendocrine mechanisms that regulate rhythms of melatonin secretion, structural synaptic plasticity, locomotor activity and sleep.
18Circadian rhythm sleep disorders.PubMed
Naveen Kanathur, John Harrington, Teofilo Lee-Chiong
Clin Chest Med. 2010 Jun;31(2):319-25. doi: 10.1016/j.ccm.2010.02.009.
Because there is insufficient cellular energy for organisms to perform their functions at the same constant rate and at the same time, all biologic processes show rhythmicity, each with its own unique frequency, amplitude, and phase. Optimal sleep and wakefulness requires proper timing and alignment of desired sleep-wake schedules and circadian rhythm-related periods of alertness. Persistent or recurrent mismatch between endogenous circadian rhythms and the conventional sleep-wake schedules of the environmental day can give rise to several circadian rhythm sleep disorders. Evaluation of suspected circadian rhythm sleep disorders requires proper monitoring of sleep diaries, often over several days to weeks. This article discusses the disorders of the circadian sleep-wake cycle and the therapeutic measures to correct the same.
19Circadian Clocks in the Regulation of Neurotransmitter Systems.PubMed
Jana-Thabea Kiehn, Frank Faltraco, Denise Palm, et al.
Pharmacopsychiatry. 2023 May;56(3):108-117. doi: 10.1055/a-1027-7055. Epub 2019 Oct 30.
To anticipate and adapt to daily recurring events defined by the earth's rotation such as light-dark and temperature cycles, most species have developed internal, so-called circadian clocks. These clocks are involved in the regulation of behaviors such as the sleep-wake cycle and the secretion of hormones and neurotransmitters. Disruptions of the circadian system affect cognitive functions and are associated with various diseases that are characterized by altered neurotransmitter signaling. In this review, we summarize the current knowledge about the interplay of the circadian clock and the regulation of psychiatric health and disease.
20Chronobiology of sleep in humans.PubMed
L C Lack, H R Wright
Cell Mol Life Sci. 2007 May;64(10):1205-15. doi: 10.1007/s00018-007-6531-2.
Periodic circadian (24-h) cycles play an important role in daily hormonal and behavioural rhythms. Usually our sleep/wake cycle, temperature and melatonin rhythms are internally synchronized with a stable phase relationship. When there is a desynchrony between the sleep/wake cycle and circadian rhythm, sleep disorders such as advanced and delayed sleep phase syndrome can arise as well as transient chronobiologic disturbances, for example from jet lag and shift work. Appropriately timed bright light is effective in re-timing the circadian rhythm and sleep pattern to a more desired time, ameliorating these disturbances. Other less potent retiming effects may also be obtained from the judicious use of melatonin and exercise.