Adenosine and dapamine receptor interactions in striatum and caffeine-induced behavioral activation

This review will examine how dopamine, a monoamine neurotransmitter, and adenosine, a neuromodulator, regulate behavioral activation, primarily as reflected by locomotor activity, in rodents. Complex interactions among 2 major types of adenosine receptors (A(1)AR and A(2A)AR) and 2 dopamine receptors (D1R and D 2 R) occur due to physical interactions that alter their ligand-binding properties and subsequent effects on common postreceptor signaling molecules. The output from these interactions in striatum modulates neurotransmission and subsequently influences spontaneous locomotor activity. Caffeine is a nonselective adenosine receptor antagonist that blocks 2 major types of adenosine receptors, AIAR and A(2A)AR, in the brain. Pharmacologic manipulation of these receptors with drugs such as caffeine offers potential therapeutic benefit for treatment of Parkinson disease.