09 September 2013
ByAppeared in BioNews 721
Scientists showed that genes coding for the production of a substance known as myelin, vital for insulating the circuitry of the brain and permitting electric impulses to be fired, are preferentially turned on during sleep.
In contrast, genes implicated in cell death and stress response were found to be switched on when mice were forced to stay awake.
'For a long time, sleep researchers focused on how the activity of nerve cells differs when animals are awake versus when they are asleep', said lead scientist Dr Chiara Cirelli from the University of Wisconsin-Madison, USA. 'Now it is clear that the way other supporting cells in the nervous system operate also changes significantly depending on whether the animal is asleep or awake’.
The researchers sequenced the whole genome of a particular type of brain cell known as an oligodendrocyte in mice after sleep, wakefulness, and sleep deprivation. These cells are involved in producing the myelin 'sheaths' that insulate nerve cells.
They found that the production of cells that become oligodendrocytes doubled during sleep and particularly during cycles of rapid eye movement, which is associated with dreaming.
Although the study was conducted in mice, the researchers say the findings suggest that chronic sleep loss might aggravate some symptoms of multiple sclerosis (MS), a disease that damages myelin. Dr Cirelli proposed future studies may investigate the effect of sleep patterns on MS symptoms.
'These findings hint at how sleep or lack of sleep might repair or damage the brain', said Professor Mehdi Tafti from the University of Lausanne, Switzerland, who was not involved with this study.
The results were published in The Journal of Neuroscience.