Effects of pramipexole on contraversive rotation and functional motor impairments in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced chronic hemiparkinsonian monkeys

Rotational and functional motor behavioral changes were studied in five MPT P lesioned chronic hemiparkinsonian Macaca nemestrina monkeys after i.m. pr amipexole, a predominant D-2 subfamily agonist. Pramipexole induced contrav ersive rotations in a dose-dependent manner with an optimal dose of 56 mu g /kg for similar to 2 to 4 hr after injection. Three different rating scales were used to determine drug-induced functional improvement. They included a monkey parkinsonism rating scale, Volitional responses to fruit presentat ions, and number of hand movements that appeared volitional. A dose of 56 m u g/kg of pramipexole produced functional improvements on hand disability, and on a parkinsonian rating scale for monkeys in a dose-dependent manner f rom 32 to 100 mu g/kg. These doses produced an increase in significant hand movements in the affected (contralateral) as well as in the normal (ipsila teral) hand to the side of,the brain lesion compared with 5% dextrose in wa ter vehicle control. With a dose of 100 mu g/kg, the therapeutic effects of pramipexole on hand movements were less than with 56 mu g/kg, due to side effects such as scratching.