Recent Research on Sleep Reveals Unexpected Connections Between Brain and Gut

Recent research conducted by neurobiologist Dragana Rogulja, PhD, principal investigator at Rogulja Lab, has identified a critical connection between the brain and the gut that, if translated into humans, could lead to new ways for improving sleep and reducing damage from sleep deprivation. The latest findings were published recently in the journal Cell.

Suppressing sensory arousal is critical for sleep, with deeper sleep requiring stronger sensory suppression, the researchers said. However, the mechanisms that enable sleeping animals to largely ignore their surroundings are not well understood.

In the study, the authors described a signaling pathway through which information about ingested proteins is conveyed from the gut to the brain to help suppress arousability. Higher protein concentration in the gut leads to increased activity of enteroendocrine cells that release the peptide CCHa1, the researchers said.

According to the paper, ACCHa1 signals a small group of dopamine neurons in the brain to modulate their activity. The dopaminergic activity regulates the behavioral responsiveness of animals to vibrations. The CCHa1 pathway and dietary proteins do not influence responsiveness to all sensory inputs, showing that during sleep, different information streams can be gated through independent mechanisms.

“We know from other research that when animals are starving, they suppress sleep in order to forage,” Rogulja in a recent interview with Harvard Medicine News. “By contrast, when they’re satiated, and especially when they’re satiated with proteins, they tend to sleep more. Now, we’ve shown that when there’s more protein in the diet, animals also sleep more deeply and become less responsive.”

Rogulja said the study findings suggest that if animals don’t need to look for food, they can disconnect from the environment and hide somewhere to sleep, which she said might be safer. More broadly, and perhaps more applicable to practitioners, she said the study implies that dietary choices impact sleep quality, and that future research efforts should aim to understand how diet could be manipulated to improve sleep.