糖心视频

Sleep may not just be rest for the mind鈥攊t may be essential maintenance for the body's power supply. A new study by University of Oxford researchers, in Nature, reveals that the pressure to sleep arises from a build-up of electrical stress in the tiny energy generators inside brain cells.

The discovery offers a physical explanation for the biological drive to sleep and could reshape how scientists think about sleep, aging, and neurological disease.

Led by Professor Gero Miesenb枚ck from the Department of 糖心视频iology, Anatomy and Genetics (DPAG), and Dr. Raffaele Sarnataro at Oxford's Center for Neural Circuits and Behavior, the team found that sleep is triggered by the brain's response to a subtle form of energy imbalance. The key lies in mitochondria鈥攎icroscopic structures inside cells that use oxygen to convert food into energy.

When the mitochondria of certain sleep-regulating brain cells (studied in fruit flies) become overcharged, they start to leak electrons, producing potentially damaging byproducts known as reactive oxygen species. This leak appears to act as a warning signal that pushes the brain into sleep, restoring equilibrium before damage spreads more widely.

"You don't want your mitochondria to leak too many electrons," said Dr. Sarnataro. "When they do, they generate reactive molecules that damage cells."

The researchers found that specialized neurons act like circuit breakers鈥攎easuring this mitochondrial electron leak and triggering sleep when a threshold is crossed. By manipulating the energy handling in these cells鈥攅ither increasing or decreasing electron flow鈥攖he scientists could directly control how much the flies slept.

Even replacing electrons with energy from light (using proteins borrowed from microorganisms) had the same effect: more energy, more leak, more sleep.

Professor Miesenb枚ck said, "We set out to understand what sleep is for, and why we feel the need to sleep at all. Despite decades of research, no one had identified a clear physical trigger. Our findings show that the answer may lie in the very process that fuels our bodies: aerobic metabolism.

"In certain sleep-regulating neurons, we discovered that mitochondria鈥攖he cell's energy producers鈥攍eak electrons when there is an oversupply. When the leak becomes too large, these cells act like circuit breakers, tripping the system into sleep to prevent overload."

The findings help explain well-known links between metabolism, sleep, and lifespan. Smaller animals, which consume more oxygen per gram of body weight, tend to sleep more and live shorter lives. Humans with mitochondrial diseases often experience debilitating fatigue even without exertion, now potentially explained by the same mechanism.

"This research answers one of biology's big mysteries," said Dr. Sarnataro. "Why do we need sleep? The answer appears to be written into the very way our cells convert oxygen into energy."