A clockwork web: circadian timing in brain and periphery, in health and disease

MH Hastings, AB Reddy, ES Maywood - Nature Reviews Neuroscience, 2003 - nature.com
MH Hastings, AB Reddy, ES Maywood
Nature Reviews Neuroscience, 2003nature.com
Circadian rhythms are daily cycles of physiology and behaviour that are driven by an
endogenous oscillator with a period of approximately (circa-) one day (diem). Exemplified in
humans by the rhythm of sleep and wakefulness and their attendant neurophysiological and
metabolic states, they are a pervasive feature of eukaryotes, enabling the organism to
anticipate and thereby adapt to the solar cycle.In mammals, the principal oscillator is the
suprachiasmatic nuclei (SCN) of the hypothalamus. The circadian timing mechanism is cell …
Circadian rhythms are daily cycles of physiology and behaviour that are driven by an endogenous oscillator with a period of approximately (circa-) one day (diem). Exemplified in humans by the rhythm of sleep and wakefulness and their attendant neurophysiological and metabolic states, they are a pervasive feature of eukaryotes, enabling the organism to anticipate and thereby adapt to the solar cycle.
In mammals, the principal oscillator is the suprachiasmatic nuclei (SCN) of the hypothalamus. The circadian timing mechanism is cell-autonomous and is expressed individually by SCN neurons. Synchrony across the SCN neuronal network is maintained by γ-aminobutyric acid (GABA) and peptide signalling. It is entrained to the light–dark cycle by glutamatergic retinal afferents, derived in part from a class of intrinsically photosensitive, melanopsin-positive retinal ganglion cells.
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