GABAB- GluK1 kainate receptor interplay modulates amygdala excitability and behavioral response to chronic stress

Abstract

Amygdala hyperexcitability is a hallmark for stress-induced anxiety disorders. Stress-associated changes in both principal neurons and interneurons contribute to the increased excitability, but how exactly these mechanisms perturb function of behaviorally relevant circuits in the amygdala remains unclear. Here, we show that GluK1 subunit-containing kainate receptors in parvalbumin (PV) interneurons maintain high GABA release and control excitability of lateral amygdala (LA) principal neurons via tonic GABAB-receptor-mediated inhibition. Downregulation of GluK1 expression in PV interneurons after chronic restraint stress (CRS) releases the tonic inhibition and increases excitability of LA principal neurons. Stress-induced LA hyperexcitability facilitates glutamatergic transmission selectively to central amygdala PKC{delta}-expressing neurons, implicated in fear generalization. Consistent with significance in anxiogenesis, absence of GluK1- GABAB regulation confers resilience against CRS-induced LA hyperexcitability and anxiety-like behavior. Our data reveal a unique novel mechanism involving an interplay between glutamatergic and GABAergic systems in the regulation of amygdala excitability in response to chronic stress.