The effect of a D2-specific dopamine agonist (Pramipexole) on response time in early Parkinson’s disease patients

The long-term use of dopamine replacement therapy leads to dyskinesias in some Parkinson’s disease (PD) patients, which may be specific to the D1 subtype of dopamine (DA) receptor. The purpose of this study was to test the effectiveness of a D2-specific DA agonist, Pramipexole, in PD patients. In a double-blind design, 6 patients took increasing doses of Pramipexole over the course of 24 weeks, and were tested in a total of 15 sessions on four measures of movement efficacy: tapping speed, simple response time, choice response time, and sequencing. Compared with 3 placebo control patients, those on active medication showed faster tapping speeds and simple response times. Choice response time and sequencing were not affected by medication status. The D2 subtype of DA receptor may be especially important in movement speed, and may contribute less to more cognitive aspects of movement.