Dopamine D1 or D2 receptor blockade in the globus pallidus produces akinesia in the rat

In the present study, the involvement of dopamine D-1 and D-2 receptors in the dorsal globus pallidus (GP) in motor control was investigated in rats. Results show that bilateral microinfusions of the dopamine D-1 receptor antagonist SCH23390 or the dopamine D-2 antagonist S(-)-sulpiride into the GP induced akinesia determined by means of the catalepsy test. These findings indicate that pallidal dopamine D-1 and D-2 receptors are critically involved in the control of motor behaviour. The findings further imply that defective dopaminergic transmission in the GP might contribute to akinesia due to lesion- or drug-induced dopamine hypofunction in experimental animals and in neurodegenerative diseases, e.g. Parkinson's disease, affecting the nigrostriatal dopamine system. (C) 1999 Elsevier Science B.V. All rights reserved.