Estradiol effect on short-term object memory under hypocholinergic condition
Brain Research Bulletin
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Estrogens positively affect object recognition memory (ORM). However, whether this effect rely on acetylcholine is unknown. Here we investigated if 17 beta-estradiol (E2) would be able to recover ORM deficits in animals with decreased expression of the Vesicular Acetylcholine Transporter (VAChT KDHET). We found that E2 improved short-term ORM (STM) in VAChT KDHET male and in OVX female mutant mice. However, E2 did not recover long-term (LTM) ORM in both sexes. Next, we tested whether hippocampal ERs activation could also rescue STM in mutant mice. Our results showed that ER alpha seems to be both sufficient and necessary for STM consolidation in female VAChT KDHET. Differently, in male, both ER alpha and ER beta activation recovered STM. In addition, we tested whether mRNA level of estrogen receptors (ER) is also sensitive to VAChT expression. Female mutant mice showed lower levels of ER alpha (ER alpha) mRNA in the hippocampus, while no differences in male were observed. Together, our results showed that under hypocholinergic function, E2 improve short-term object recognition in both male and female. Furthermore, we showed that changes in VAChT expression might potentially modulate hippocampal ER alpha expression in a sex-dependent-manner.