Using a rat model of L-DOPA-induced dyskinesia (LID), the contributions of 
dopamine D1 and D2 receptors to axial, limb, and orolingual (ALO) abnormal 
involuntary movements (AIMs) elicited by L-DOPA were examined. Chronic 
L-DOPA-treated rats received the D1 receptor antagonist SCH23390 (0.01, 0.1, and 
1.0 mg/kg; i.p.), the D2 receptor antagonist Eticlopride (0.01, 0.1, and 1.0 
mg/kg; i.p.), a mixture of both antagonists (0.01, 0.1, 1.0 mg/kg each; i.p.), 
or vehicle 30 min prior to L-DOPA (6 mg/kg; i.p.)+Benserazide (15 mg/kg; i.p.). 
SCH23390 (0.1 and 1.0 mg/kg) significantly reduced axial and limb AIMs, while 
the same doses of Eticlopride significantly decreased axial, limb, and 
orolingual AIMs. Co-administration of SCH23390+Eticlopride significantly reduced 
axial (0.01, 0.1 and 1.0 mg/kg), limb (0.1 and 1.0 mg/kg), and orolingual (0.1 
and 1.0 mg/kg) AIMs. These results indicate the importance of D1 and D2 
receptors to LID and further validate the rat AIMs model.