Sleep and Melatonin in Diurnal and Nocturnal Rodents

大量研究表明，褪黑素可以诱导人类睡眠。然而，导致这种效应的大脑机制尚不清楚。这是由于缺乏褪黑素催眠作用的实验室啮齿动物模型；用褪黑激素诱导实验室啮齿动物睡眠的尝试使用了夜间活动的啮齿动物，这意味着啮齿动物在周期的黑暗阶段活动，如大鼠和丛林仓鼠。褪黑素并不能持续地诱导这些啮齿动物入睡。事实上，在大多数这些研究中，褪黑素减少了睡眠，增加了觉醒。由于这些夜间活动的动物在夜间最活跃，此时褪黑激素的分泌最高，因此这些结果应该不会令人惊讶。需要一种昼夜啮齿动物模型来证明褪黑素的催眠作用。尼罗河鼠(Arvicanthis Niloticus)是一种昼夜活动的小鼠，是研究褪黑素催眠作用的理想动物。此外，以这种啮齿动物为模型，可以研究褪黑激素诱导睡眠的大脑回路。这些研究的结果可能会阐明褪黑激素如何用于治疗失眠和

Numerous studies have shown that melatonin can induce sleep in humans. However, the brain mechanisms responsible for this effect are unknown. This is due to the lack of a laboratory rodent model of the soporific effects of melatonin; attempts to induce sleep with melatonin in laboratory rodents have used nocturnal rodents, meaning rodents active during the dark phase of the cycle, such as rats and Djungarian hamsters. Melatonin does not consistently induce sleep in these rodents. In fact, in most of these studies, melatonin reduced sleep and increased wakefulness. Because these nocturnal animals are most active during the night, when melatonin secretion is the highest, these results should not be surprising. A diurnal rodent model is needed to demonstrate the sleep-inducing effects of melatonin. Arvicanthis niloticus (unstriped Nile grass rat), a diurnal murid rodent, is an ideal animal in which to demonstrate the sleep-inducing effects of melatonin. Further, using this rodent as a model, the brain circuitry through which melatonin induces sleep can be investigated. Results from these studies may clarify how melatonin can be used to treat insomnia and