Caffeine and a selective adenosine A2A receptor antagonist induce sensitization and cross-sensitization behavior associated with increased striatal dopamine in mice.

Background: Caffeine, a nonselective adenosine A1 and A(2A) receptor antagonist, is the most widely used psychoactive substance in the world. Evidence demonstrates that caffeine and selective adenosine A(2A) antagonists interact with the neuronal systems involved in drug reinforcement, locomotor sensitization, and therapeutic effect in Parkinson's disease (PD). Evidence also indicates that low doses of caffeine and a selective adenosine A(2A) antagonist SCH58261 elicit locomotor stimulation whereas high doses of these drugs exert locomotor inhibition.