LE300 is a dopamine D1-like receptor antagonist (Kis = 1.9 and 7.5 nM in CHO cell membranes expressing human dopamine D1 and D5 receptors, respectively) and antagonist of the serotonin (5-HT) receptor subtype 5-HT2A (pA2 = 8.32 in a rat tail artery assay). It is selective for dopamine D1 and D5 over D2L and D4.4 receptors (Kis = 44.7 and 109 nM, respectively). LE300 inhibits the conditioned avoidance response in the pole-jump test in rats (ED50 = 0.94 mg/kg), which is predictive for antipsychotic-like activity. It also reduces locomotor activity in the open field test in rats (ED50 = 0.74 mg/kg).
