Motor System
How does estrogen induce its effects at the level of the striatum?
- its is presently unknown
- there are few neurons in the striatum that accumulate estrogen (few estrogen receptors)
- effects of estrogen may be nontraditional, that is, estrogen may act at the membrane of nerve terminals to enhance dopamine release versus control of gene transcription; there is evidence for rapid effects of gonadal steroids on membranes (but we don’t know, in most cases, how these rapid effects occur)
- it is possible that estrogen may alter other neurocircuits that project to the striatum and that regulate dopamine release (e.g., frontal cortex)
- it is also possible that estrogen may influence the amount of dopamine available for release; there are dopamine neurons within the substantia nigra that possess estrogen receptors
- however, these latter observations do not explain how estrogen implants within the striatum can alter dopamine release and behavior