Orexin-A

Jan 3, 2008 08:26 GMT  ·  By

Sleeping less than 7-8 hours per night could cut short your life because of cardiovascular issues, with an increase of 110 %, as revealed by some researches. Another recent research has showed that sleep loss in children (and not only) makes them prone to obesity. Sleep loss has also been connected to lowered immune system (meaning vulnerability to infections).

But, the most affected organ by the sleep loss is the brain. Sleep loss can induce from cognitive to psychological impairments, varying from memory loss and impaired learning to attention deficit hyperactivity disorder and depression.

In a new research published in the "Journal of Neuroscience", researchers at Wake Forest University School of Medicine have managed to remove the effects of sleep deprivation on cognitive performance by administering orexin-A, a natural brain peptide, to monkeys.

"These findings are significant because of their potential applicability. This could benefit patients suffering from narcolepsy and other serious sleep disorders. But it also has applicability to shift workers, the military and many other occupations where sleep is often limited, yet cognitive demand remains high", said Samuel A. Deadwyler, Ph.D., professor of physiology and pharmacology at Wake Forest.

Orexin-A (also called hypocretin-1) is synthesized by a small number of brain cells and controls sleep. It works on many brain nuclei for the daytime and normal levels of orexin-A are connected to wakefulness. Sleep loss forces the brain to synthesize more orexin-A, but that it is not effective in achieving alertness past the biological day-night cycle.

The subject monkeys were maintained awake overnight for 30 to 36 hours using videos, music, treats and interaction with technicians, until tested the next day. The tests revealed their cognitive performances were highly impaired. But when these monkeys received orexin-A either intravenously or through a nasal spray just before the testing, their cognitive abilities matched those at non-sleep-deprived state. Also, it appeared that the intranasal spray had a more potent effect than the intravenous administration.