Experiments involving the use of behavioural, neurochemical and electrophysiological methods to explore the mechanisms mediating the effects of oestrogen on dopaminergic activity in the striatum on the female rat are described. Results have shown that oestrogen influences the activity of striatal dopamine terminals and dopamine-mediated behaviours in the female rat. These are rapid effects of oestrogen in the striatum, and are thought to be mediated by a novel membrane-associated receptor. How these novel effects of oestrogen may affect naturally occurring behaviours in the rat will be discussed.