Identification of a dopamine pathway that regulates sleep and arousal in Drosophila.

Sleep is required to maintain physiological functions, including memory, and is regulated by monoamines across species. Enhancement of dopamine signals by a mutation in the dopamine transporter (DAT) decreases sleep, but the underlying dopamine circuit responsible for this remains unknown. We found that the D1 dopamine receptor (DA1) in the dorsal fan-shaped body (dFSB) mediates the arousal effect of dopamine in Drosophila. The short sleep phenotype of the DAT mutant was completely rescued by an additional mutation in the DA1 (also known as DopR) gene, but expression of wild-type DA1 in the dFSB restored the short sleep phenotype. We found anatomical and physiological connections between dopamine neurons and the dFSB neuron. Finally, we used mosaic analysis with a repressive marker and found that a single dopamine neuron projecting to the FSB activated arousal. These results suggest that a local dopamine pathway regulates sleep.