Involuntary movements, or dyskinesias, represent a debilitating complication of levodopa therapy for Parkinson's disease experienced by the vast majority of the patients. We hypothesize that dyskinesia may be caused, at least in part, by changes in the location of dopamine receptors. Indeed, while receptors are thought to be at the surface of the neurons, pharmacological stimulation may lead to their internalisation and, subsequently, to changes in the transduction of the signal they convey. Taking advantage of an immediately available - dyskinetic - brain bank, we will investigate the possibility of a correlation between an altered expression and/or sub-cellular localisation of dopamine receptors and the occurrence and/or severity of dyskinesia. Such an investigation would help to define the 'safest' rhythm of levodopa administration to patients.