TN. Continuous dopaminergic stimulation reduces risk of motor complications in parkinsonian primates. Exp Neurol 2005;192:73–78

Abstract

Abstract Levodopa or short-acting dopamine (DA) agonist treatment of advanced parkinsonian patients exposes striatal DA receptors to nonphysiologic intermittent stimulation that contributes to the development of dyskinesias and other motor complications. To determine whether continuous dopaminergic stimulation can delay or prevent onset of motor complications, four MPTP-lesioned, levodopa-naive cynomolgus monkeys were implanted subcutaneously with apomorphine containing ethylene vinyl acetate rods. Three other MPTP-lesioned monkeys received daily injections of apomorphine. Animals receiving apomorphine rods showed improved motor function (dONT state) within 1 day of implantation, and remained continually dONT for the duration of treatment (up to 6 months) without developing dyskinesias. Injected animals also showed similar improvement in motor function after each apomorphine injection. However, these primates remained dONT for only 90 min and within 7-10 days all developed severe dyskinesias. Implanted monkeys evidenced local irritation, which was alleviated by steroid co-therapy.