Sleep, Adenosine, and Neurodegeneration

Sleep is a complex, critical behavior that is under the control of homeostatic and circadian processes. Homeostatic sleep reflects increasing sleep drive or need in correlation with waking duration and its resolution during sleep. It is mediated in large part through the adenosine (ado) system. Ageing results in changes in the ado system and, often, complaints of sleep disturbance. Sleep disturbance is a common symptom across neurodegenerative diseases and greatly impacts quality of life. In this chapter we will discuss two relatively common neurodegenerative diseases, Alzheimer's (AD) and Parkinson's (PD), which together encapsulate many of the sleep disturbances associated with neurodegenerative disease. In regards to AD, there is emerging evidence of a bidirectional influence of AD and sleep disruption. Alternatively, in regards to PD, parasomnias can herald neurodegeneration several years prior to appearance of characteristic motor symptoms. Additionally, the ado system as a possible therapeutic target will be briefly discussed.