INDO SWISS - new media

NewsScientists Solve the Mysteries of SleepA Lausanne University research team hastaken a step closer to answering aquestion that has baffled scientists forcenturies – why do humans need to sleep?Studying sleep deprivation in mice, theteam has managed to determine whathappens in the brain at the molecularlevel when asleep, and to isolate a genethat regulates sleep activity."I was always amazed that no one knewwhy we sleep," Mehdi Tafti, head of theresearch project at Lausanne University'sCentre for Integrative Genomics said.Tafti, an expert in sleep disorders, hasspent the past 20 years trying to work outwhy humans spend a third of their lives inbed.His research team recently published theirfindings in the Proceedings of the NationalAcademy of Science journal, identifying agene – Homer1a – that controls levels ofcalcium in neurons in the brain.Mice, like humans, need calcium tofunction when awake, but the longer theyare up and about, the more calciumbuilds up, and when the levels get toohigh, the neurons get over-stimulated.Sleep, therefore, is nature's way ofreducing these excessive calcium levels inthe brain. And Homer1a plays a key role."This gene regulates the levels of calciumto protect against hyperactivity of thebrain," explained Tafti. "The more you stayawake, the more it is activated."It rings an alarm bell in your head and triesto counterbalance the build-up, warning:"Be careful, calcium is trying to get in – youhave to regulate it otherwise it's going tobe toxic," he added.Sleep deprivation"In animal models, sleep deprivation islethal; sleep deprived rats or mice die aftertwo or three weeks – but we don't know35why," said the Lausanne professor. "It has never been tested in humansbut long-term sleep deprivation would probably lead to death."Whether you are able to snooze until midday or wake up at the crack ofdawn is all down to your genes, say experts. But what's the minimumamount of shut-eye we can get by on each night?"The hypothesis is that there is a core amount of sleep that everybodyneeds, probably about five to six hours," he said."I always say it's like food intake. You need a certain amount of food butyou know that everybody eats more than what we need. Sleep isregulated in the same way."Possible applicationsThe fact that humans also possess the Homer1a gene therefore opensup a huge field for possible medical applications. It could be used tohelp people control their tiredness and stay awake longer, or at theother extreme improve the recovery process during sleep.Tafti also imagines possible uses for treating people suffering fromdepression or schizophrenia. The scientists believe that there is a highchance the newly identified gene has an important influence on thesleeping disorders of people suffering from depression.Contrary to what might first be imagined, sleep deprivation is anextremely potent anti-depressant. "The problem is that it doesn't lastlong as when they go back to sleep they wake up depressed," he said."If you remove this gene in mice, they may have a depressive-likebehaviour and if you over-express the gene you can treat thedepression," said Tafti. Tests using humans are expected to start withinthe next four to five years.INDO-SWISS BUSINESS + JAN-FEB 2008