Browsing by Subject "Neuroscience"

Chronic stress has been linked to the pathogenesis of various disorders, such as generalized anxiety disorder, depression, and post-traumatic stress disorder (PTSD). Stress-induced hyperexcitability of the basolateral amygdala (BLA) has implications in anxiety-like behavior. Promising evidence points to the direction of GluK1 subunit containing kainate receptors (KARs) having a role in the modulation of GABAergic transmission in the lateral amygdala (LA). The aim of the present study was to investigate whether dysfunction of KARs contribute to stress-induced amygdala hyperexcitability and anxiogenesis in mice. Chronic restraint stress (CRS) is an animal model simulating chronic psychological stress. An in situ hybridization experiment was performed to investigate how CRS affects expression levels of GluK1 in the different neuronal populations in the LA. These data show that CRS leads to downregulation of GluK1 expression in the parvalbumin-positive (PV+) interneurons specifically. Patch clamp recordings of spontaneous inhibitory postsynaptic currents showed that CRS did not affect synaptic GABAergic transmission to the principal neurons in the LA. Lastly, conditional knock-out (cKO) mice that have the Grik1 gene knocked out selectively in the PV-expressing interneurons showed no change in anxiety-like behavior after CRS while their wild-type counterparts demonstrated an increase in anxiety-like behavior observable in the elevated plus maze test. Thus, ablation of GluK1 in PV+ interneurons affects the stress-induced anxiogenesis. Due to low number of animals, it cannot be confirmed yet whether the deletion leads to stress resilience or a phenotype where even regular handling is an aversive experience comparable to physical restraint. GluK1 KAR modulation of PV+ interneuron excitability and its susceptibility to stress-related alterations is only a recently discovered phenomenon, and even though this study provides some insight into the underlying mechanism, further research is needed. Systematic characterization of the mechanism could provide a novel tool for understanding and treating stress-related pathological anxiety, possibly helping patients suffering from anxiety disorders resistant to current treatments available.