Millions of patients taking prescription sleeping pills may not wake up through a fire alarm, the researchers warned.
Tests on mice showed that half of the rodents administered a type of benzodiazepines – which include Xanax and Valium – failed to rise to surprising noise.
However, Japanese scientists found that mice taking an experimental hypnotic drug were able to wake up with the deafening fire alarm.
The researchers argue that DORA-22 does not stir the ability to wake up during a deep sleep by allowing the sensitive "guardian" of the brain to remain alert.
Tests on mice showed that half of the rodents administered a type of benzodiazepines – which include Xanax and Valium – failed to rise to surprising noise
The scientists at Kagoshima University also discovered mice that, given the new class of drugs, went back to sleep just as quickly as those of benzol.
They tested their theory in sleeping mice. The results were published in the scientific journal Frontiers in Behavioral Neuroscience.
One third of the rodents was given DORA-22, while the other two groups received a benzodiazepine called triazolam or a placebo.
Researchers led by Professor Tomoyuki Kuwaki then attempted to awaken the rats sleeping deeply with a threatening urge.
This included the smell of a fox, a sharp dog whistle or the trembling of their cage – designed to match that of an earthquake.
The results revealed that waking times were "significantly delayed" in mice treated with triazolam, but not in the group taking DORA-22.
YOUNG PEOPLE ARE ADMITTED TO PILLS IN SLEEP?
The amount of 18-year-olds treated for addiction to sleeping pills and anxiolytics nearly doubled in a year, as shown in December.
Cases of dependence on benzodiazepines increased by 96%, from 161 in 2016 to 2017, to 315 in 2017 and 2018.
Treatment for Xanax addiction, a potent type of anti-anxiety medication, has seen a five-fold increase among young people.
Experts said the figures are only the "tip of the iceberg", since many more children could be dependent on Xanax, which is more than 200 times stronger than the Valium.
And further analysis of the data showed that the mice taking the experimental drug fell asleep as fast as those treated with triazolam.
Professor Kuwaki and colleagues now hope to see if the DORA-22 sleep promotion effect also works in humans.
Commenting on his research, he said: "Our study provides important and promising information on the safety of these hypnotics".
The researchers were then able to further demonstrate that triazolam can cause a delay in waking up to a threat.
They discovered that the three groups of mice woke up "just as quickly" when the oxygen levels in their cage were deliberately lowered.
DORA, or double orexin receptor antagonists as they are known medically, have only been developed in the last decade.
They operate selectively aiming at the brain's sleep and the awakening of the paths, compared to the more powerful effects of benzos.
Even during sleep, the brain continually processes sensory information like noises, waking up if it detects a threat.
The benzos stimulate a brain receptor that causes drowsiness and suppresses the "gatekeeper", who decides which sensory input to process.
The figures show that around 100 million prescriptions for benzene, often administered to treat anxiety, are written in the United States each year.
And there are 12 million prescriptions for benzosome, which have a strong reassuring effect, in the UK every year, the data show.