title: Basic science review on circadian rhythm biology and circadian sleep disorders.
abstract: The sleep-wake cycle displays a characteristic 24-hour periodicity, providing an opportunity to dissect the endogenous circadian clock through the study of aberrant behaviour. This article surveys the properties of circadian clocks, with emphasis on mammals. Information was obtained from searches of peer-reviewed literature in the PUBMED database. Features that are highlighted include the known molecular components of clocks, their entrainment by external time cues and the output pathways used by clocks to regulate metabolism and behaviour. A review of human circadian rhythm sleep disorders follows, including recent discoveries of their genetic basis. The article concludes with a discussion of future approaches to the study of human circadian biology and sleep-wake behaviour.
authors.affiliation: Department of Medicine, National University Hospital, Singapore. Kong_Leong_TOH@nuh.com.sg
authors.forename: Kong Leong
authors.initials: KL
authors.lastname: Toh
mesh_terms: D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D006801:Humans; D009475:Neurons, Afferent / Q000502:physiology; D009476:Neurons, Efferent / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D020178:Sleep Disorders, Circadian Rhythm / Q000235:genetics / Q000503:physiopathology*; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000502:physiology; D015534:Trans-Activators / Q000502:physiology
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D015534:Trans-Activators; C538960:BMAL1 protein, human; C538943:CLOCK protein, human