Astrocytes Modulate Sleep

In a study of sleep regulation in mice, researchers for the first time have uncovered evidence that brain cells that aren't neurons can affect behavior. Philip G. Haydon of Tufts University and colleagues focused on astrocytes, which are glial cells that nestle up to synapses, the junctions between neurons. The researchers had previously shown that astrocytes release adenosine triphosphate. ATP is hydrolyzed by enzymes to form adenosine. The adenosine then binds to A1 receptors on the neurons and dampens their activity. In their new work, the researchers studied transgenic mice that release less adenosine than normal from their astrocytes. After sleep deprivation these mice displayed less craving for sleep than normal mice, Haydon's team found. The transgenic mice also avoided the memory problems that develop in normal mice after sleep deprivation. Normal mice treated with a compound that prevents adenosine from binding to neuronal A1 receptors also avoided these memory problems (Neuron 2009, 61, 213). Astrocytes could thus offer a promising new target for the development of treatments for sleep and cognitive disorders.