Much of what determines whether you sleep well or badly happens in a tiny area of the brain consisting of just a few thousand nerve cells, or neurons. Now, researchers at Oregon Health Sciences University have discovered that a chemical produced within the brain can slow the activity of those cells almost to a stop, effecting the body's reaction to light and darkness. The research, published in the March 15 issue of The Journal of Neuroscience, opens an entirely new avenue of research towards understanding the molecular basis of sleep disorders and problems related to natural light cycles, such as seasonal affective disorder (SAD).
The research focuses on an area deep in the brain called the suprachiasmatic nucleus (SCN), which is about the size of a pinhead. The SCN is known to regulate the circadian rhythm -- the 24-hour cycle of sleep and wakefulness. When neurons in the SCN are damaged, the sleep cycle is disrupted.
"The connection between these brain cells and the circadian cycle is clear," said Charles Allen, Ph.D., associate professor in OHSU's Center for Research on Occupational and Environmental Toxicology and lead author of the Journal of Neuroscience study. "Now we have powerful evidence that a substance we call orphanin alters the response of this area of the brain to light."
Orphanin (also known as nociceptin, or OFQ), is a peptide, or combination of amino acids that are the basic building blocks of proteins. This peptide is at work in several areas of the brain.
"The areas where orphanin is active, besides in the SCN, play a role in
feeding, drinking behavior, nursing behavior, reproductive behavior, regulation
of body temperature and reward, among other things," said David Grandy, Ph.D.,
associate professor of physiology and pharmacology at OHSU and senior author of
the paper. Orphanin acts as a neurotransmitter, a kind of messenger that tells
cells how to act. While its role elsewhere in t
Contact: Henry Sessions
Oregon Health & Science University