ABSTRACT
Dopamine has long been known to be an important neurotransmitter in the striatum. It has been implicated in the pathophysiology of Parkinson’s disease (PD) (Hornykiewcz, 1973), dystonia (Nygaard, Marsden and Duvoisin, 1988), Tourette’s syndrome (Singer and Walkup, 1991), schizophrenia (Nemeroff and Bissette, 1988; Seeman et al., 1997) and drug addiction (Nestler and Aghajanian, 1997). In spite of its prominence, the physiological impact of dopamine has remained something of a mystery, particularly within the striatum. Claims have been made that dopamine is excitatory or inhibitory or neither.
