Abstract
Introduction
Sleep during early life is thought to be important for brain development. Indeed, disruptions in sleep during development have long-lasting effects on cognitive functioning. Recently, our lab has developed the LarvaLodge platform for monitoring sleep in developing Drosophila larvae. Using this system we can investigate the neural circuits and signals controlling sleep during early neurodevelopmental periods. Neuropeptides play critical roles in regulating many behaviors in both larvae and adult flies.While several neuropeptides modulate sleep in adult flies, it is not known what role neuropeptides play in controlling larval sleep.
Methods
To identify peptidergic neurons that regulate 2nd instar larval sleep, we activated neurons labeled by 34 independent Gal4 driver lines corresponding to 25 different neuropeptide genes using the heat-sensitive cation channel, TrpA1.
Results
Of the 34 Gal4 driver lines, we determined that 2 lines are wake-promoting and 7 lines are sleep-promoting. A subset of these exert effects on sleep without associated changes in wake activity levels. We also observed sleep fragmentation (increase in sleep bout number and decrease in sleep bout length) in 3 lines. Subsequent analysis indicated that manipulation of activity in Diuretic hormone 44 (Dh44)-labeled neurons bidirectionally modulates sleep-wake. Additionally, pan-neuronal knockdown of Dh44 altered sleep duration.
Conclusion
This work indicates that neuropeptidergic signaling modulates sleep during early development and provides a platform to examine how neuropeptidergic regulation of sleep/wake changes throughout the lifespan.
Support
NIH T32
Regulation of coordinated muscular relaxation in Drosophila larvae by a pattern-regulating intersegmental circuit
