Sleep deprivation increases A 1 adenosine receptor density in the rat brain

Abstract

Adenosine, increasing after sleep deprivation and acting via the A 1 adenosine receptor (A 1AR), is likely a key factor in the homeostatic control of sleep. This study examines the impact of sleep deprivation on A 1AR density in different parts of the rat brain with [ 3H]CPFPX autoradiography. Binding of [ 3H]CPFPX was significantly increased in parietal cortex (PAR) (7%), thalamus (11%) and caudate-putamen (9%) after 24 h of sleep deprivation compared to a control group with an undisturbed circadian sleep-wake rhythm. Sleep deprivation of 12 h changed receptor density regionally between − 5% and + 9% (motor cortex (M1), statistically significant) compared to the circadian control group. These results suggest cerebral A 1ARs are involved in effects of sleep deprivation and the regulation of sleep. The increase of A 1AR density could serve the purpose of not only maintaining the responsiveness to increased adenosine levels but also amplifying the effect of sleep deprivation and is in line with a sleep-induced homoeostatic reorganization at the synaptic level.