PD 89211 is a selective dopamine D4 receptor antagonist with high selectivity for the DA D4.2 receptor (> 800-fold) as compared to other hDA receptor subtypes, rat brain serotonin, and adrenergic receptors. In vitro, PD 89211 reverses quinpirole-induced [
SKF-80723 HBr is a D1 receptor agonist. SKF-80723 HBr strongly potentiated the contralateral circling induced by quinpirole in rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the medial forebrain bundle.