Dopaminergic control of locomotion, mouthing, snout contact, and grooming: opposing roles of D1 and D2 receptors

The study compares the behavioral profiles induced in rats (N=118) by the D2-dopaminergic receptor agonist quinpirole (0.03 and 0.5 mg/kg), and the D1-agonist SKF38393 (1.25–40 mg/kg), and both agonists administered together. Locomotion and snout contact frequency were reduced by the low but increased by the high dose of quinpirole; SKF38393 also reduced these behaviors and attenuated the effect of the high quinpirole dose. Only the high dose …