Levodopa induces dyskinesias in normal squirrel monkeys

This study assessed whether or not levodopa induces dyskinesias in normal ( ie, unlesioned) squirrel monkeys. All six animals treated twice daily with levodopa (15 mg/kg with carbidopa, by oral gavage) for two weeks developed choreoathetoid dyskinesias, whereas none of the vehicle-treated animals dis played any abnormal movements. These dyskinesias did not merely reflect a g eneralized motor activation as locomotion was actually suppressed. The pres ent data demonstrate that preexisting nigrostriatal damage is not necessary for the development of levodopa-induced dyskinesias.