Our brain’s mitochondria may play a crucial role in the onset of sleep

The components of the cells that provide them with energy can play an unexpected role in sleep. A fruit flies study suggests that mitochondria in the brain help to trigger sleep when they feel that insects have been awake for too long – and the same mechanism can exist in people.

Researchers already understand how the brain reacts to sleep deprivation. These include neural shooting changes, structural forms within cells and how the genes are expressed. They have also identified specific neurons in the brain that light up at the start of sleep, but are less sure of what tells these neurons to shoot.

“Sleep is one of the very large biological puzzles,” said Gero Miesenböck at the University of Oxford. To better understand him, he and his colleagues used sequencing and fluorescent markers to study the genes expressed by the neurons of the sleep center in around 1000 female female (Drosophila Melangaster), who sleep for 1 p.m. to 4 p.m. during a day, usually at night.

The team has let about half of the flies spend a full night, while others were awake, either by slowly trembling the tubes in which they were or by genetically managing them so that their neurons favoring the alarm was activated by an increase in temperature.

Among the private sleep flies, the researchers found that the neurons inducing sleep increased the activity of the genes involved in the race and the maintenance of their mitochondria. These mitochondria have also shown signs of stress, such as the shortage of small pieces, cleaning damaged parts and the formation of contact points with neighboring structures that help repair.

This stress can arise from the fact that mitochondria continue to produce energy even when neurons are inactive. The researchers observed that this led to an accumulation of electrons that escape, generate free radicals – unstable molecules that can damage DNA – and finally trigger pressure to sleep, explains Miesenböck. When these flies were finally allowed to sleep, mitochondrial damage was repaired.

The researchers also found that flies with fragmented mitochondria in their sleep neurons were sleeping less than normal and did not make up for it after being awake. On the other hand, the flies whose mitochondria were designed to merge more easily, suggesting better repair mechanisms, slept more than usual and showed a stronger rebound after sleep deprivation. This supports the idea that mitochondria is involved in sleep pressure.

In another part of the experience, flies have been designed to have increased mitochondrial activity in response to light. The team found that 1 hour of artificial light caused an increase in sleep to 20 to 25%, compared to control flies.

While the study studied the brain of flies, not people, mitochondria are relatively similar between animals. He supports the idea that aerobic metabolism – energy production from nutrients and oxygen, which takes place in the mitochondria of most animals – can cause sleep pressure in humans, explains Ryan Mailloux at McGill University in Quebec, Canada.

This new understanding could possibly guide sleep treatments. “This offers us new opportunities to target these ways [and] Take a walk with new effective ways to treat people who have sleep problems, ”explains Mailoux.

Michele Bellesi at the University of Cameroon in Italy says “it is definitely a strong and stimulating newspaper”, but he questions his conception. “Sleep deprivation is not just a prolonged awakening,” he says. “It can introduce additional stressors that can trigger cellular responses beyond those directly linked to the accumulation of sleep pressure.”

In response, Miesenböck says that his team used various ways to keep the flies awake, including the edition of genes via normal and non -stressful temperature changes for insects, and they all had the same effects on mitochondria. “What this study has revealed is that the sleep homeostat actually looks at its own mitochondria to estimate the need for sleep,” he said.