<unk>  is a selective antagonist at the adenosine A2A receptor (A2AR), but the precise mechanism by which it exerts its therapeutic effect in Parkinson's disease is unknown. However, it is known that dimers of these receptors form heterotetramers with the dimers of dopamine D2 receptors (D2R) within striatum. Adenosine acts as an endogenous A2AR agonist, but also as a negative allosteric modulator (NAM) within these tetramers towards D2Rs, thus inhibiting the D2R mediated effects of dopamine, an endogenous D2R agonist.<unk>  is believed to bind a A2AR within a A2AR-D2R-tetramer and function as a NAM towards the other A2AR (instead of D2R), thus inhibiting the effects of adenosine and enhancing the movement (locomotion) promoting effects exerted by dopamine via D2R. However, at high<unk>  concentration, it causes locomotion depression akin to caffeine (which is a broad-spectrum adenosine receptor antagonist), and might do so by displacing adenosine, and working as a NAM towards D2R (instead of A2AR).
Istradefylline
Tezacaftor
Tasimelteon
Ladostigil
Naldecon
Buffalopox
Toremifene
Pleconaril