Many theories about dopaminergic function in Parkinson's disease are b
ased upon the effects of the D2 receptor. Standard treatments mostly i
nvolve dopaminergic D2 agonists. However, the recent development of do
paminergic D1 agonists should help to clarify the role of the D1 recep
tor in the treatment of Parkinson's disease. The authors review the ph
ysiopathological, behavioural and therapeutic data on D1 agonists admi
nistered in animal models and in patients.