White night, the moon is bright. people sleep less deeply when there is a full moon, the researchers found when they analyzed data from a past sleep study.
Henri Rousseau (1897), Museum of Modern Art, New York; Corbis Images
Insomniacs desperate for some ZZZS may one day have a safer way to get them. Scientists have developed a new sleep drug that induces sleep in rodents and monkeys apparently without affecting cognition, a potentially dangerous side effect common sleep aids. The discovery, which originated in the work explaining narcolepsy, could lead to a new class of drugs that help people who do not respond to other treatments.
Between 10% and 15% of Americans chronically struggling to get or stay asleep. Many of them are turning to sleeping pills for relief, and most are drugs such as zolpidem (Ambien) and eszopiclone (Lunesta) prescribes that slow the brain by binding to receptors for GABA, a neurotransmitter that is involved in mood, cognition and muscle tone. But because the drugs target GABA indiscriminately, they can also affect cognition, causing memory loss, confusion and other problems with learning and memory, and a number of strange sleepwalking behaviors including wandering, eating, and driving while sleeping. This has led many researchers to seek alternative mechanisms for inducing sleep.
neuroscientist Jason Uslaner Merck Research Laboratories in West Point, Pennsylvania, and colleagues decided to tap into the brain orexin system. Orexin (also known as hypocretin) is a protein that controls wakefulness and lacking in people with narcolepsy. Previous studies induced sleep successfully inhibiting orexin, but had not examined its effects on cognition. Researchers have developed a new compound called orexin inhibiting DORA-22 and confirmed that it would induce sleep in rats and rhesus monkeys as effectively as GABA-modulating drugs.
Next, the researchers went about testing its effects on animals drug cognition. They measured cognition and memory in rodents rats assessing the ability to recognize objects. They presented rats with new object-say, a cone or a sphere that rats then sniffed and explored. Then they took the absent object for one hour. After this time, the rats were exposed to a new object and that they had come to know; if the rats could remember, they spent less time checking the familiar object. With primates, Uslaner team tested their ability to match colors on a touch screen and pay attention and identify the origin of a flashing light. In all cases, the researchers found the sleeping pills modulating GABA caused both rats and primates to respond more slowly and less accurately. Monkeys taking tests of memory and attention, for example, are 20% less precise on the highest dose of each of the modulation of GABA drugs. But DORA-22 had no such effect on cognition, the team reports today in Science Translational Medicine .
"We were very excited," said Uslaner. "People who take sleep medications should be able to perform cognitive tasks when they wake up, and this [compound] could help them do so without loss of value."
Although DORA-22 has not yet been tested in humans, it is very promising to help people who suffer from sleep disorders, says Emmanuel Mignot, a sleep researcher with the school of medicine Stanford University in Palo Alto, California. "This study is encouraging and exciting, because there are good reasons to believe it would work differently than what we used in the past," said Mignot, who helped discover the link between orexin (or lack ) and narcolepsy. "Not all medications work for everyone, so it's really, really good news to have a potential new drug on the horizon."
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