Objective: Allopregnanolone is an endogenous neuroactive steroid that, through its binding to the gamma-aminobutyric acid (GABA) A receptor, has GABA-active properties. Animal studies indicate that allopregnanolone administration results in diminished learning and memory impairment. The aim of the current study was to investigate the effect of intravenously administered allopregnanolone on episodic memory, semantic memory, and working memory in healthy women.
Materials and methods: Twenty-eight healthy women were included in the study. The participants were scheduled for the memory tests twice in the follicular phase. During the test sessions, an intravenous allopregnanolone and placebo infusion were administered in a double-blinded, randomized order at intervals of 48 h. Before and 10 min after the allopregnanolone/placebo injections, memory tasks were performed.
Results: The study demonstrated that allopregnanolone impaired episodic memory in healthy women. There was a significant difference between pre- and postallopregnanolone injection episodic memory scores (p < 0.05), whereas there was no change in episodic memory performance following the placebo injections. There was also a significant difference between allopregnanolone and placebo postinjection episodic memory scores (p < 0.05). There were no effects of allopregnanolone on the semantic memory task or working memory task.
Conclusion: Intravenous allopregnanolone impairs episodic memory in healthy women, but there is a high degree of individual variability.