In the mammalian brain dopamine systems play a central role in the con
trol of movement, hormone release, emotional balance and reward. Alter
ation of dopaminergic neurotransmission is involved in Parkinson's dis
ease and other movement disorders, as well as in some psychotic syndro
mes. This review summarises recent findings, which shed some light on
signals and cellular interactions involved in the specification and ma
turation of the dopaminergic function during neurogenesis. In particul
ar we will focus on three major issues: (1) the differentiation of dop
aminergic neurones triggered by direct contact with the midbrain floor
plate cells through the action of sonic hedgehog; (2) the neurotrophi
c factors acting on dopaminergic neurones; and (3) the role of target
striatal cells on the survival and the axonal growth of developing or
grafted dopaminergic neurones.