A drug that could help people get a better night's sleep while improving their memory is being tested by scientists. Experts say the formula may also curb over-eating and prevent addiction - although so far it has only been tested on rats.
Almost a third of the population suffers from insomnia, but only 10% of those take any medication. Pharmaceutical companies have long been searching for the perfect sleeping pill to try to attract their custom.
According to Chemistry and Industry magazine, the company Actelion has developed a pill that not only induces sleep but also increases the dreaming phase, consolidating memory at the same time. Because the drug acts on the orexin hormone system, experts say it may also have an effect on appetite.
Orexin, a hormone discovered in 1998, is known to control eating and help regulate sleep. Malfunctions in this system can cause narcolepsy, a condition where people fall asleep uncontrollably.
Actelion's candidate drug orexin-RA-1 is said to block the orexin system. In laboratory experiments rats given the drug slept soundly and performed better in maze tests the next day, suggesting that their memory had improved. Measurements of brain activity during the sleep trials showed an increase in the dreaming parts of sleep, known as rapid eye movement (Rem) sleep, when brain activity is almost as intense as during waking hours.
"The dream phase is when memory is hardwired in the brain," Jean-Paul Clozel, the chief executive of Actelion, told Chemistry and Industry. He said traditional sleeping pills reduced Rem sleep, causing users to wake up tired and groggy.
Shahrad Taheri, a lecturer in medicine at the University of Bristol and one of the first people to experiment on orexin, said a drug acting on this system may have other beneficial effects. "Over-eating is associated with obesity, and orexin is thought to be involved in feeding regulation," he said. "Blocking the orexin system could also help the person to eat less."
The fact that narcoleptics are resistant to amphetamine addiction also suggests an application in preventing addiction.
But there could be downsides with targeting the hormone. People with narcolepsy suffer episodes of muscle weakness that can range from a barely perceptible slackening of the jaw muscles to complete collapse, and it is possible that the drug could spark similar problems. There are also questions about whether a small increase in Rem sleep would actually make any difference, said Dr Taheri.
Orexin-RA-1 is now in the second phase of clinical trials, which means it will be tested on people before being licensed for sale to the public. Mr Clozel said that the drug could be on the market by 2012.
According to its manufacturers, the new drug shows no signs of being addictive or losing its effect over time - unlike existing sleeping pills. Other pharmaceutical companies are also targeting the orexin system, but their drugs have not yet reached the clinical trials.
