Table 1.

Ki (nm) values at cloned receptors

Drug	D2	D3	D4
L-741,626	2.4	100	220
U-99194A	1572	78	>2000
L-745,870	960	2300	0.43

Receptor selectivity based on in vitro Ki (nm) at cloned dopamine D₂, D₃, and D₄, receptors for L-741,626 (Kulagowski et al., 1996), U-99194A (Waters et al., 1993), and L-745,870 (Kulagowski et al., 1996).