[Pathophysiology of Parkinson's disease: an update].

Considerable progress has been made in the pathophysiology of Parkinson's disease in the last 25 years. To better understand the nature and diversity of the symptoms of Parkinson's disease it is necessary to integrate clinical knowledge on 1) the role of dopamine, 2) the anatomical and functional organization of the basal ganglia, and 3) the dysfunctions observed in MPTP-treated monkeys. This article reviews the principal discoveries in these three research fields and their contribution to our understanding of the pathophysiology of Parkinson's disease.