Intra-striatal estradiol in female rats impairs response learning within two hours of treatment

► 2 days and 2 h of intrastriatal estradiol-sulfate impaired response learning. ► 2 hrs after infusion, middle and high but not low doses impaired learning. ► 500 nM dose impaired learning similarly following the 2 h and 48-24-2 h paradigms. ► Response learning was not modulated by any dose given 15 min prior to training.