darke read this
:When cells in a certain part of the brain become overworked, a compound in the brain kicks in, telling them to shut down. This causes people to become drowsy and fall asleep. Alter that natural process by adding coffee or tea, and the brain compound - called adenosine - is blocked, and people stay awake.
Prolonged increased neural activity in the brain's arousal centers triggers the release of adenosine, which in turn slows down neural activity in the arousal center areas. Because the arousal centers control activity throughout the entire brain, the process expands outward and causes neural activity to slow down everywhere in the brain
"We knew that coffee kept us awake," Dr. Greene( professor of psychiatry and senior author of the study in the University of Texas Southwestern Medical Center)said. "Now we know why: Coffee and tea are blocking the link between the prolonged neural activity of waking and increased levels of adenosine in cells, which is why they prevent us from getting drowsy."
Past studies by Dr. Greene and his colleagues have shown that adenosine may act as a "fatigue factor." When adenosine levels increase in the arousal centers -- as happens with prolonged waking -- mammals tend to fall asleep. But what hasn't been known before is what triggers the release of adenosine to induce sleep.
these findings may be usefull in the future treatment of insomnia and other sleep disorders...
this was a briefing of a longer article published in internet...if anyone is interested for the full article here's the link:
http://www8.utsouthwestern.edu/utsw...les/218303.html