Sleep-active neuron specification and sleep induction require FLP-11 neuropeptides to systemically induce sleep

摘要

Sleep keeps us healthy and happy, and is essential for all animals. Specialized neurons in the brain become highly active to generate this restful state. There are relatively few of these “sleep-active” neurons in the brain, but they are able to control sleep in the entire animal. Like most other neurons, sleep-active neurons release substances called neurotransmitters. The sleep-active neurons in many different species release a neurotransmitter called GABA, although they also contain other neurotransmitters called neuropeptides that were thought to be less important for triggering sleep. The roundworm Caenorhabditis elegans has become an important model system for studying the molecular biology of sleep as it contains only one sleep-active neuron. Turek et al. have now studied this C. elegans neuron and have discovered transcription factors – proteins that control gene expression – that are required for the sleep-active neuron to induce sleep. Further investigation revealed that the transcription factors specify the production of a neuropeptide called FLP-11. The sleep-active neuron always contains FLP-11, but only releases it as sleep begins. Once released, FLP-11 moves onto target cells to induce sleep in the entire organism. Thus, FLP-11 – and not GABA – is the major sleep-inducing neurotransmitter in C. elegans. To induce a sleep state throughout an entire organism, the activities of many different cells must be controlled. A future challenge will be to figure out how FLP-11 does this.