Background:

Raclopride is a dopamine D2/D3 receptor antagonist, which binds to D2 and D3 receptors with dissociation constants (Kis) of 1.8 nM and 3.5 nM, respectively, but has a very low affinity for D1 and D4 receptors with Kis of 18000 nM and 2400 nM, respectively[1].

参考文献:
[1]. Seeman P, et al. Dopamine receptor pharmacology. Trends Pharmacol Sci. 1994 Jul;15(7):264-70.