Sex Differences in the Memory Enhancements Effects of 17²-Estradiol

Mentor 1

Karyn Frick

Mentor 2

Wendy Koss

Location

Union Wisconsin Room

Start Date

28-4-2017 1:30 PM

End Date

28-4-2017 4:00 PM

Description

Infusions of estradiol into the dorsal hippocampus immediately following training increases the memory in object placement and object recognition tasks in ovariectomized female mice. In females, the E2-induced memory enhancements are mediated through cell-signaling cascades including the extracellular signal-regulation kinase (ERK) cascade. In males, systemic post-training injection of E2 enhances spatial memory consolidation, but the signaling pathways necessary for E2 to enhance memory formation in males is unknown. To investigate this, female mice were ovariectomized and male mice were left gonadally-intact and then implanted with bilateral dorsal hippocampal cannulae. Immediately after in object placement and object recognition tasks, mice received bilateral infusion of vehicle or E2. In the second experiment, male mice were castrated and compared to intact males in the same behavioral tasks. This allowed us to investigate whether endogenous estrogens have any effects on E2's memory enhancements. In both experiments, it was confirmed that E2 increased memory in both castrated and intact male mice similar to ovariectomized female mice. Next, we tested whether the ERK pathway was required for the memory enhancements, as it is for females. In this experiment, castrated male mice were implanted with triple cannulae in the dorsal hippocampus and dorsal third ventricle (ICV). Immediately after training in object tasks, mice received infusions of vehicle or E2 into the ICV and vehicle or an ERK inhibitor (U0126) into the dorsal hippocampus. Results showed that U0126 did not affect the enhancement of memory consolidation by E2 in either object task. This would suggest that E2-induced memory enhancements in males do not work through the same biochemical pathway as females. Further studies of the other cell signaling pathways such as mTOR and PI3K/AKT, is necessary to determine the biochemical processes responsible for the increase of memory consolidation in males after E2 treatment.

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Apr 28th, 1:30 PM Apr 28th, 4:00 PM

Sex Differences in the Memory Enhancements Effects of 17²-Estradiol

Union Wisconsin Room

Infusions of estradiol into the dorsal hippocampus immediately following training increases the memory in object placement and object recognition tasks in ovariectomized female mice. In females, the E2-induced memory enhancements are mediated through cell-signaling cascades including the extracellular signal-regulation kinase (ERK) cascade. In males, systemic post-training injection of E2 enhances spatial memory consolidation, but the signaling pathways necessary for E2 to enhance memory formation in males is unknown. To investigate this, female mice were ovariectomized and male mice were left gonadally-intact and then implanted with bilateral dorsal hippocampal cannulae. Immediately after in object placement and object recognition tasks, mice received bilateral infusion of vehicle or E2. In the second experiment, male mice were castrated and compared to intact males in the same behavioral tasks. This allowed us to investigate whether endogenous estrogens have any effects on E2's memory enhancements. In both experiments, it was confirmed that E2 increased memory in both castrated and intact male mice similar to ovariectomized female mice. Next, we tested whether the ERK pathway was required for the memory enhancements, as it is for females. In this experiment, castrated male mice were implanted with triple cannulae in the dorsal hippocampus and dorsal third ventricle (ICV). Immediately after training in object tasks, mice received infusions of vehicle or E2 into the ICV and vehicle or an ERK inhibitor (U0126) into the dorsal hippocampus. Results showed that U0126 did not affect the enhancement of memory consolidation by E2 in either object task. This would suggest that E2-induced memory enhancements in males do not work through the same biochemical pathway as females. Further studies of the other cell signaling pathways such as mTOR and PI3K/AKT, is necessary to determine the biochemical processes responsible for the increase of memory consolidation in males after E2 treatment.