Nitric oxide inhibition abolishes sleep-wake differences in cerebral circulation. Am J Physiol Heart Circ Physiol 280: H2598–H2606, 2001.—Nitric oxide (NO), being produced by active neurones and also being a cerebral vasodilator, may couple brain activity and blood flow in sleep, particularly during active sleep (AS), which is characterized by widespread neural activation and markedly elevated cerebral blood flow (CBF) compared with quiet wakefulness (QW) and quiet sleep (QS).
