Glial Cells Found to Influence Sleep Regulation and Metabolism in Fruit Flies

Recent research conducted by scientists at the Max Planck Institute for Neurobiology of Behavior–Caesar (MPINB) in Germany has uncovered new insights into how glial cells in the brain impact vital behaviors such as sleep, rest, and feeding, using fruit flies (Drosophila melanogaster) as a model. Published in Nature Neuroscience, the study emphasizes the role of non-neuronal glial cells in maintaining metabolic and behavioral homeostasis.

Homeostasis refers to an organism’s ability to regulate internal conditions like temperature, hydration, and blood sugar levels despite external changes. These mechanisms also govern behaviors essential for survival, including sleep and feeding. The research aimed to identify neural signals that reflect the need for sleep—termed sleep homeostasis—and how these signals are modulated during different behavioral states.

Lead author Andres Flores-Valle explained that even though humans spend about a third of their lives sleeping, the underlying reasons for this necessity remain only partially understood. Fruit flies, despite their simple brains, exhibit sleep-like behaviors and serve as a powerful model for studying sleep regulation.

Using advanced in vivo imaging techniques, the team tracked glial activity in freely moving flies to observe how these cells respond during wakefulness and sleep. They focused on two types of glia: astrocyte-like glia, which help maintain chemical stability, and ensheathing glia, which wrap around nerve fibers and aid in repair and debris removal. Their experiments revealed that glial calcium signals—indicative of activity—rise during periods of wakefulness and reset following sleep, suggesting these cells monitor sleep pressure.

Surprisingly, they discovered that neurons previously thought to trigger sleep actually respond more strongly to feeding needs, with activity levels increasing until the fly consumes food. Additionally, glial calcium activity was linked to metabolic processes, such as clearing carbon dioxide and regulating pH levels, indicating that sleep may play a role in restoring metabolic balance.

This research demonstrates that glial cells are sensitive to metabolic cues and that their activity influences sleep regulation. These findings could pave the way for new investigations into the contribution of glia to sleep and metabolic disorders. The team aims to further explore how glial cells initiate the transition from wakefulness to sleep, with the hypothesis that elevated glial calcium activity after prolonged wakefulness triggers sleep onset.

Overall, the study highlights the importance of glial cells in maintaining physiological and behavioral stability, offering promising avenues for understanding sleep and metabolism in humans.

Source: https://medicalxpress.com/news/2025-05-glial-cells-play-key-role.html