Intracerebral dialysis was used to simultaneously monitor extracellular dopamine (DA) in striatum and behaviour in rats following administration of amphetamine and sulpiride. Amphetamine (2 mg/kg s.c.) caused a marked release of DA into striatal perfusates, an effect which was potentiated in rats pretreated with sulpiride (50 mg/kg s.c.). Amphetamine-induced stereotyped head and forepaw movements were potentiated by sulpiride at a time point corresponding with the enhanced release of DA. In comparison, amphetamine-induced locomotor activity was completely inhibited by sulpiride.