Postprandial sleep mechanics in Drosophila

Area of Science:

• Neuroscience
• Chronobiology
• Animal Behavior

Background:

• Postprandial sleepiness is a common phenomenon, but its underlying regulatory mechanisms remain largely unexplored.
• Understanding how food intake influences sleep is crucial for comprehending circadian rhythms and metabolic regulation.

Purpose of the Study:

• To investigate the relationship between food consumption and sleep patterns in individual flies.
• To identify specific meal components and neural circuits that regulate postprandial sleep.

Main Methods:

• Simultaneous measurement of sleep and food intake in individual flies.
• Manipulation of leucokinin (Lk) signaling pathways and neuronal activity using thermogenetics and RNA interference.
• Identification of novel neuronal populations involved in sleep regulation.

Main Results:

• A transient increase in sleep was observed following meals, correlated with ingested volume, protein, and salt content.
• Silencing leucokinin receptor (Lkr) neurons specifically reduced protein-induced sleep.
• Leucokinin (Lk) neuron stimulation decreased postprandial sleep, while Lk downregulation increased it, suggesting an inhibitory role.
• A novel subset of inhibitory neurons regulating Lkr neurons was identified.

Conclusions:

• Postprandial sleep is dynamically regulated by specific meal properties and neural circuits.
• The leucokinin (Lk)-leucokinin receptor (Lkr) pathway plays a key role in modulating sleep after eating.
• Novel inhibitory neuronal inputs to the Lk-Lkr circuit contribute to the cyclical gating of postprandial sleep.