Adenosine A2A, but not A1, receptors mediate the arousal effect of caffeine

Nat Neurosci. 2005 Jul;8(7):858-9. doi: 10.1038/nn1491.


Caffeine, a component of tea, coffee and cola, induces wakefulness. It binds to adenosine A1 and A2A receptors as an antagonist, but the receptor subtype mediating caffeine-induced wakefulness remains unclear. Here we report that caffeine at 5, 10 and 15 mg kg(-1) increased wakefulness in both wild-type mice and A1 receptor knockout mice, but not in A2A receptor knockout mice. Thus, caffeine-induced wakefulness depends on adenosine A2A receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arousal / drug effects*
  • Arousal / physiology*
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Mice
  • Mice, Knockout
  • Receptor, Adenosine A2A / physiology*
  • Wakefulness / drug effects
  • Wakefulness / physiology


  • Central Nervous System Stimulants
  • Receptor, Adenosine A2A
  • Caffeine