Why humans sleepy?

Scientists already know why humans need sleep. But scientists are still puzzled how the brain decides when humans need sleep. Recent research could provide clues about it. A recent study in mice get brain cells called astrocyte as a booster to sleep by releasing adenosine. It is a chemical substance that causes drowsiness and can be reduced by caffeine.

The longer human or animal awake, the greater sleepiness. It is called the pressure to sleep. The study found adenosine as a trigger for sleep pressure. These chemicals collected during waking hours, which helps stimulate the unique pattern of brain activity that occurs during sleep.

"Adenosine of astrocyte clearly important in causing sleep pressure", said team member Michael Halassa of Tufts University School of Medicine in Boston.

This study is the first non-nerve cells in the brain shows the influence, said Halassa. Differences with the neuron, astrocyte not trigger electrical pressure.

"This research could be to produce better drugs to encourage drowsiness if needed and prevent drowsiness if dangerous," said Merrill Mitler of the National Institute of Neurological Disorders and Stroke.