School of Agriculture, Biomedicine & Environment, La Trobe University, Melbourne, Australia.
J Comp Physiol B. 2024 Jun;194(3):233-239. doi: 10.1007/s00360-023-01480-x. Epub 2023 Mar 11.
The behaviors that characterize sleep have been observed across a broad range of different species. While much attention has been placed on vertebrates (mostly mammals and birds), the grand diversity of invertebrates has gone largely unexplored. Here, we introduce the intrigue and special value in the study of sleeping platyhelminth flatworms. Flatworms are closely related to annelids and mollusks, and yet are comparatively simple. They lack a circulatory system, respiratory system, endocrine glands, a coelom, and an anus. They retain a central and peripheral nervous system, various sensory systems, and an ability to learn. Flatworms sleep, like other animals, a state which is regulated by prior sleep/wake history and by the neurotransmitter GABA. Furthermore, they possess a remarkable ability to regenerate from a mere fragment of the original animal. The regenerative capabilities of flatworms make them a unique bilaterally symmetric animal to study a link between sleep and neurodevelopment. Lastly, the recent applications of tools for probing the flatworm genome, metabolism, and brain activity make their entrance into the field of sleep research all the more timely.
睡眠行为在广泛的不同物种中都有观察到。虽然脊椎动物（主要是哺乳动物和鸟类）受到了很多关注，但无脊椎动物的巨大多样性在很大程度上仍未被探索。在这里，我们介绍了研究睡眠扁形动物扁形动物的有趣之处和特殊价值。扁形动物与环节动物和软体动物密切相关，但相对简单。它们缺乏循环系统、呼吸系统、内分泌腺、体腔和肛门。它们保留了中枢和外周神经系统、各种感觉系统以及学习能力。扁形动物像其他动物一样睡眠，这种状态受到先前的睡眠/觉醒历史和神经递质 GABA 的调节。此外，它们还具有从原始动物的一小部分再生的惊人能力。扁形动物的再生能力使它们成为一种独特的两侧对称动物，可以研究睡眠和神经发育之间的联系。最后，最近用于探测扁形动物基因组、代谢和大脑活动的工具的应用，使得它们更及时地进入睡眠研究领域。
