Sleep disruption, oxidative stress, and aging: New insights from fruit flies

摘要

It is now well established that sleep in the fruit fly Drosophila melanogaster shares many key characteristics with mammalian sleep. As in mammals, sleep in Drosophila (ⅰ) consists of periods of sustained quiescence associated with an increased arousal threshold; (ⅱ) is modulated by stimulants such as caffeine, modafinil, and amphetamines (4) and by hypnotics such as antihistamines; (ⅲ) is associated with changes in brain activity; and (ⅳ) is characterized by changes in the expression of hundreds of genes. Drosophila sleep, like mammalian sleep, also shows both a circadian and a homeostatic regulation. Flies, like humans, are diurnal animals, and their circadian system is responsible for consolidating most of their sleep during the night. The homeostatic system is responsible for the fact that the longer the waking period is, the longer and more intense the subsequent sleep period is (7). In flies, like in mammals, the duration of sleep increases after sleep deprivation, and the amount of sleep recovered depends on prior time awake. The intensity of sleep also increases after sleep loss, and sleep becomes less fragmented, i.e., the number of brief awakenings during the night decreases, whereas the duration of each sleep episode increases. Like humans, sleep-deprived flies also show reduced vigilance and are less capable of performing certain tasks. Sleep in flies, like in mammals, is also more abundant in young flies than in adult flies. In a recent issue of PNAS, Koh et al. make the important observation that in flies, like in mammals, including humans, sleep also becomes more fragmented with aging. Thus, they demonstrate yet another important similarity between Drosophila and mammalian sleep, further establishing fruit flies as a model system for the genetic dissection of sleep mechanisms and functions.