Honors Capstone Project
Date of Submission
Arts and Science
estradiol, regulating learning and memory
Capstone Prize Winner
Won Capstone Funding
Sciences and Engineering
Biotechnology | Integrative Biology
As the most potent circulating form of estrogen in most young adult female mammals, estradiol has extensive effects on physiological functioning. Estradiol effects are especially notable with the drop in the hormone observed when a woman transitions into menopause, with accompanying changes not only in overall physiology but also in brain functions. Recent research reveals the complex effects estradiol has on regulating learning and memory that vary by type of cognitive task among other variables. In particular, increased estradiol levels improve performance on hippocampus-dependent tasks, but impair performance on striatum-dependent tasks through direct actions on these different memory systems. Estradiol’s bidirectional cognitive effects might result from regulation of energy substrate availability and metabolism, a hypothesis tested in the present research. Prior research done in our lab revealed via microdialysis that peripheral injections of estradiol to ovariectomized female rats significantly increased glucose and lactate concentrations in the extracellular fluid of the hippocampus. The goal of the current study is to to determine the effects of estradiol on basal extracellular substrate concentrations in the striatum using similar microdialysis procedures. Results showed no significant effects of low-dose peripheral estradiol injections (4.5 μg/kg) on extracellular glucose concentration, which was 2.75±0.17 mM with control oil injections and 2.61±0.14 mM with estradiol injections. However, rats treated with estradiol had significantly lower extracellular lactate concentrations of 0.508±0.018 mM compared to 0.617±0.029 mM in oil-treated controls. Further, assays on serum showed no change in peripheral concentrations of glucose and lactate with estradiol, suggesting changes are specific to the striatum and not simply a result of altered systemic availability. These findings reveal the role of bioenergetics underlying estradiol’s regulation of memory systems and point to potential neural processes that become dysregulated with female aging and reproductive senescence.
D'Amico, Ella, "Estrogens Regulate Metabolic Substrate Concentrations in Brains of Young Adult Female Rats: A Multiple Memory Systems Approach" (2016). Honors Capstone Projects - All. 956.
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