June 12 (UPI) -- Scientists in Japan successfully triggered a hibernation-like state in mice by activating a specific group of brain cells.
The research, published this week in the journal Nature, suggests even animals that don't naturally sleep through the winter are capable of hibernation.
Entering a hibernation-like state could help astronauts conserve food and water, as well as avoid the ill-effects of microgravity, on long journeys through space.
Hibernation isn't simply prolonged sleep. When food gets scarce and winter approaches, hibernating animals begin to slow down their metabolism and drop their body temperature. During their prolonged slumber, hibernating animals quiet their brains and slow their heart rate and breathing.
As a result, bears, snakes, turtles and other hibernating species are able to conserve energy. When spring arrives, the animals wake having lost a little weight, but are otherwise healthy.
Mice don't hibernate in the wild. But in the lab, researchers were able to coax mice into a hibernation-like state by activating a type of brain cell called Q neurons.
"The mice exhibited distinctive qualities that met the criteria for hibernation," Takeshi Sakurai, researcher at the University of Tsukuba, said in a news release. "In particular, the body temperature set-point lowered from about 96.8 degrees Fahrenheit to about 81 degrees Fahrenheit, and the body functioned normally to maintain a lower body temperature around 71.6 degrees Fahrenheit, even when the surrounding ambient temperature was dramatically reduced."
During their approximately weeklong hibernation, the mice had slower heart rates, reduced oxygen consumption and slower respiration.
While mice don't normally hibernate for weeks or months at a time, they do experience what is called daily torpor, a daily period of diminished physiological activity. However, researchers were able to replicate the hibernation-like state in rats, which neither hibernate nor experience daily torpor.
Researchers say the experiment suggests it's possible humans possess Q neurons, or comparable brain cells, that could be manipulated to trigger a hibernation-like state.
"People might not want to hibernate for the same reasons as animals," said Genshiro Sunagawa of the RIKEN Center for Biosystems Dynamics Research. "But there are medical reasons for wanting to place people in suspended animation, such as during emergency transport or critically ill conditions as in severe pneumonia, when the demand for oxygen cannot meet the supply."
"In the future, we may put humans in a hibernation-like state for missions to Mars and beyond," said Sakurai.