L-741,626 is a selective D2DR inhibitor. L-741,626 acts selectively at the D2 receptor with such affinity that it can be used as a probe to determine if D2 receptors mediate the effects of compounds of interest. This approach was used to determine the dopamine receptor involved in PD 128907 agonism, where antagonism of the effects of PD 128907 by L-741,626 indicated a D2-mediated action.