The effect of escapable and inescapable stress on perineuronal nets and parvalbumin in the rat medial prefrontal cortex
Abstract
Exposure to inescapable stress (IS) produces anxiety- and depressive- like behavior in male rats, whereas escapable stress (ES) attenuates such behaviors even after subsequent IS. ES increases activity in the medial prefrontal cortex (mPFC), which inhibits the dorsal raphe nucleus (DRN) to block anxiety- and depressive- like behavior. These stressors may alter perineuronal nets (PNNs); extracellular matrix structures that surround parvalbumin (PV) interneurons during development and stabilize their synaptic connections in adulthood. When PNNs are removed they restore plasticity. The effect of stress on PNNs and PV interneurons is unclear. Here we tested the hypothesis that stress alters the staining intensity of PNNs and PV in the mPFC. We used three rat groups: a control group (stayed in home cage); an ES group (100 tails shocks that could be terminated by the rat spinning a wheel); and an IS group (the same shocks given to the ES-treated rats but given a wheel that had no consequences). Immunohistochemistry was done to triple label cells for c-Fos, PV, and PNNs. IS rats had increased c-Fos intensity, but decreased PV and PNN intensities compared to control and ES. No differences in cell number were observed between groups. The increased c-Fos intensity suggests that there is higher activity in mPFC PV interneurons of IS rats. Future studies will examine DRN neuronal connections to mPFC PV interneurons and the role of neuronal activity on PV. Further understanding the mechanism behind stress resiliency is expected to lead to more effective therapies for anxiety and depression.
About the Presenter
Abigail Gligor
Abigail Gligor is a graduating senior in the Neuroscience program at Washington State University Vancouver. As an undergraduate, she studied the role of perineuronal nets and parvalbumin interneurons in drug addiction, memory, and stress. Previously, she has showcased her work at various conferences including the Society for Neuroscience meeting in Oregon. Now she works at Legacy Research Institute, where she is continuing her studies of perineuronal nets by examining the structural role of their component, aggrecan.