Poster abstracts

Poster number 83 submitted by Emma Woodward

The impact of prepubertal ovariectomy and estradiol replacement on anxiety-like behaviors following chronic stress: a preliminary report

Emma Woodward (Neuroscience Graduate Program), Laurence Coutellier (Department of Psychology, The Ohio State University)

Abstract:
Stress-induced psychiatric disorders including depression and anxiety are more common in women and are associated with reduced neuronal activity in the prefrontal cortex (PFC). Activity in the PFC is partially regulated by parvalbumin (PV) interneurons, a type of GABAergic inhibitory interneuron with fast-spiking properties that has been implicated in emotional regulation and the stress response. Our lab has shown that chronic stress increases the activity of prefrontal PV+ cells in both male and female mice but that PV+ activation leads to anxiety-like behavior in females only. We hypothesize that this sex-specific increase in vulnerability to stress is due to the actions of 17beta-estradiol on PV+ cells during puberty, when levels of gonadal hormones increase and act on the still-developing PFC. Research indicates that the increase of female gonadal hormones at puberty is necessary for the maturation of inhibitory neurotransmission in the frontal cortex. Therefore, 17beta-estradiol may play a role in the female-specific development of anxiety-like behavior following chronic stress. In this experiment, female mice were subjected to prepubertal ovariectomy or sham surgery on postnatal day (P)25 and were supplemented with 17beta-estradiol or vehicle once daily until adulthood. Three weeks after surgery, mice underwent four weeks of chronic unpredictable mild stress (UCMS). Anxiety-like behavior was assessed following completion of the UCMS protocol. Preliminary results indicate that mice who undergo ovariectomy prior to puberty, and who do not receive estradiol replacement, have reduced anxiety-like behavior and increased depressive-like behavior following four weeks of UCMS compared to sham animals. These findings may be due to elimination of the organizational effects of 17beta-estradiol on PV+ cell maturation in the PFC and suggest that 17beta-estradiol may contribute to increased vulnerability to stress-induced psychiatric disorders in females.

Keywords: parvalbumin, prefrontal cortex, estradiol