A-381393 is a potent, selective, brain penetrate dopamine D4 receptor antagonist, with Kis of 1.5, 1.9 and 1.6 nM for human dopamine D4.4, D4.2, and D4.7 receptor, respectively, >2700-fold selectivity over D1, D2, D3 and D5 dopamine receptors. A-381393 shows moderate affinity for 5-HT2A (Ki, 370 nM)[1].
A-381393 exhibits weak affinity at 5-HT1A, Sigma 2, Adenoceptor α1A, Adenoceptor α2C, Histamine H1, with Kis of 1365, 8600, 2044, 1912 and 2962 nM, respectively[1].
Reference:
[1]. Nakane M, et al. 2-[4-(3,4-Dimethylphenyl)piperazin-1-ylmethyl]-1H benzoimidazole (A-381393), a selective dopamine D4 receptor antagonist. Neuropharmacology. 2005 Jul;49(1):112-21.