Lulu Xie 1 , Hongyi Kang , Qiwu Xu , Michael J Chen , Yonghong Liao , Meenakshisundaram Thiyagarajan , John O'Donnell , Daniel J Christensen , Charles Nicholson , Jeffrey J Iliff , Takahiro Takano , Rashid Deane , Maiken Nedergaard
Oct 18 2013
The conservation of sleep across all animal species suggests that sleep serves a vital function. We here report that sleep has a critical function in ensuring metabolic homeostasis. Using real-time assessments of tetramethylammonium diffusion and two-photon imaging in live mice, we show that natural sleep or anesthesia are associated with a 60% increase in the interstitial space, resulting in a striking increase in convective exchange of cerebrospinal fluid with interstitial fluid. In turn, convective fluxes of interstitial fluid increased the rate of β-amyloid clearance during sleep. Thus, the restorative function of sleep may be a consequence of the enhanced removal of potentially neurotoxic waste products that accumulate in the awake central nervous system.