Poster abstracts
Poster number 89 submitted by Emma Woodward
Impact of Pubertal Ovarian Hormones on PV+ Interneuron Maturation in Stress-Sensitive Brain Regions
Emma M. Woodward (Neuroscience Graduate Program), Jennifer Ackerman (Department of Psychology), Laurence Coutellier (Department of Psychology, Department of Neuroscience)
Abstract:
Stress-induced neuropsychiatric disorders, including anxiety disorders, are over twice as common in women than men, however this sex difference in prevalence of anxiety disorders does not emerge until pubertal onset. This suggests that there may be a role for ovarian hormones in organizing sex-specific vulnerability to anxiety. Prefrontal parvalbumin (PV) interneurons, which mature during adolescence in a process mediated by estradiol, are sensitive to stress and mediate anxiety-like behavior in female mice only. We recently found that prepubertal ovariectomy increases activation of prefrontal PV+ interneurons in non-stressed female mice and prevents the stress-induced increase in prefrontal PV+ interneuron activation and anxiety-like behavior as previously observed. Therefore, we hypothesize that ovarian hormones at puberty contribute to the both the normal maturation of PV+ interneurons and organize the stress-sensitive properties leading to the hyperactivation of these cells in the PFC of females following chronic stress. Here, we aim to investigate the role of pubertal ovarian hormones on PV+ interneurons in other stress-sensitive brain regions, including basolateral amygdala (BLA) and ventral hippocampus (vHC). Female mice were subjected to prepubertal or adult ovariectomy or sham surgery followed by four weeks of chronic mild stress. We then used immunohistochemistry to assess markers of PV+ interneuron maturation, including total number of PV+ interneurons, PV+ interneuron activity through co-labeling with FosB, and proportion of PV+ interneurons surrounded by perineuronal nets (PNNs). We also quantified VGLUT and VGAT puncta as markers of glutamatergic and GABAergic transmission. We expect that chronic stress will increase PV/PNN co-localization in the BLA and vHC, and decrease PV+ interneuron activation and GABAergic transmission. Additionally, we expect that prepubertal ovariectomy will protect against this decrease in inhibitory drive in the BLA and vHC. Our preliminary data in the vHC show that chronic stress increases PV and PNN expression with no effect of prepubertal ovariectomy. Further results from this study will provide insight into the role of ovarian hormones in the organization of inhibitory circuitry in stress-sensitive brain regions at puberty.
Keywords: parvalbumin, perineuronal nets, chronic stress