Motor response to repeated dopaminergic stimulation in Parkinson's disease.

Recent studies giving subcutaneous apomorphine or intravenous levodopa boluses have not found clear evidence of behavioral hyposensitivity to repeated dopaminergic stimulation in Parkinson's disease (PD). Here we analyze that data, and review experimental findings in animal models and our previous experience with parkinsonian patients. We conclude that acute tolerance to pulsatile stimulation is likely to play a role in the pathophysiology of motor fluctuations in PD.