Sleep is an important process essential for life and regulated by homeostasis and circadian. However, the mechanism and function of sleep are still unclear. The recently developed Drosophila model for sleep provides a powerful system to genetically and pharmacologically identify molecular that regulate sleep. Dopamine is an important neurotransmitter known to affect many behaviors, it also involves in sleep/wake cycle regulation in Drosophila. Although dopamine is associated with arousal threshold, the neural circuit which controls arousal threshold by release dopamine hasn’t been identified. Here, we investigated a dopaminergic single neuron, VPL, which released dopamine to regulate sleep strength. Sleep became fragment as the dopamine level was reduced in Murashka-1. On the other hand, when we reduced dopamine level in most dopaminergic neuron by TH-Gal4 driver, flies were significantly easy to initiate sleep and sleep strength was increased. These data indicated that dopamine may control different character of sleep in different neural circuits. The final sleep phenotype is the sum of performance of every single neuron which is involved in sleep behavior.

謝誌------------------------------------------------------2 中文摘要--------------------------------------------------3 Abstract--------------------------------------------------4 Introduction----------------------------------------------5 Materials and Methods-------------------------------------8 Results--------------------------------------------------11 Discussion-----------------------------------------------14 References-----------------------------------------------16 Figure---------------------------------------------------19 Appendix-------------------------------------------------29

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