Even after long periods of sleep when adenosine is at its lowest concentration in the brain, the number of brain cells bound with adenosine remains very large.

Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells.

Besides binding to sites in the brain, adenosine is known to be involved in biochemical reactions throughout the body.

Some areas of the brain that are relatively inactive nonetheless release some adenosine.

Stress resulting from a dangerous situation can preserve wakefulness even when brain levels of bound adenosine are high.