Circadian Rhythm of Amyloid Beta
A 2009 report demonstrated that amyloid beta production follows a circadian rhythm, rising when an animal (mouse) or person is awake and falling during sleep. The wakefulness-promoting neuroprotein orexin was shown to be necessary for the circadian rhythm of amyloid beta production. The report suggested that excessive periods of wakefulness (i.e. due to sleep debt) could cause chronic build-up of amyloid beta, which could hypothetically lead to Alzheimer's disease. This is consistent with recent findings that chronic sleep deprivation is associated with early onset Alzheimer's disease.
Melatonin is also involved in circadian rhythm maintenance. Notably, melatonin has been connected with the "sundowning" phenomenon, in which Alzheimer's disease patients that have amyloid plaques in the hypothalamus exhibit exacerbation of Alzheimer's disease symptoms late in the day. This "sundowning" phenomenon could be directly or indirectly related to the recently discovered continuous increase in amyloid beta throughout the day.
Read more about this topic: Beta Amyloid
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