Samuel A. Deadwyler of Wake Forest University School of Medicine in Winston-Salem, N.C., said Orexin-A, also known as hypocretin-1, is a naturally occurring peptide produced in the brain that regulates sleep. It's secreted by a small number of neurons but affects many brain regions during the day and people who have normal amounts of orexin-A are able to maintain wakefulness.

When people or animals are sleep-deprived -- the brain attempts to produce more orexin-A, but often without enough success, Deadwyler said.

The research team of Linda Porrino and Robert Hampson, also of Wake Forest, and Jerome Siegel of the University of California at Los Angeles, studied the effects of orexin-A on monkeys that were kept awake overnight for 30 to 36 hours with videos, music, treats and interaction with technicians.

The study, published in the Journal of Neuroscience, found the sleep-deprived monkeys performance of cognitive problems was significantly impaired. However, monkeys administered orexin-A intravenously or via a nasal spray immediately prior to testing had their cognitive skills improved to the normal, non-sleep-deprived, level.