Sex and estradiol effects in the rodent dorsal striatum.

17β-Estradiol (E2) is a sex hormone that acts on many brain regions to produce changes in neuronal activity and learning. A key brain region sensitive to E2 is the dorsal striatum (also called caudate-putamen), which controls motor behaviour, goal-directed learning and habit learning. In adult rodents, oestrogen receptors (ERs) in the dorsal striatum are localized to the plasma membrane and include ERα, ERβ and G protein-coupled ER (GPER). E2, either naturally produced or exogenously applied, may influence neuronal excitability, basal synaptic transmission and long-term synaptic potentiation. These effects may be due to direct action on signalling pathways or may be due to changes in dopamine availability. In particular, estradiol influences dopamine release, dopamine receptor expression and dopamine transporter expression. We review the cellular effects that E2 has in the dorsal striatum, distinguishing between exogenously applied E2 and the oestrous cycle, as well as its influence on dorsal striatal-dependent motor and learning behaviour.