Glutamatergic neurons of basolateral amygdala mediate increased exploratory behaviors produced by mildly chronic restraint stress in adolescent mice

In response to stressors, individuals manifest varied behavioral responses directed toward satisfying physiological survival needs. Although the enduring effects of adolescent stress on both humans and animals are well-documented, the underlying mechanisms remain insufficiently elucidated. Utilizing immunofluorescence, viral injections, and brain slice electrophysiological recordings, we have delineated that heightened excitability among glutamatergic neurons in the basolateral amygdala (BLA) is responsible for inducing heightened exploratory behaviors in adolescent mice subjected to mild, chronic restraint stress. Activation of BLA glutamatergic neurons through chemogenetics increases exploratory behaviors in emotional assessments, whereas inhibition of these neurons diminishes exploratory behaviors in measures such as the open field and elevated plus maze test. Furthermore, an upregulation of glutamate receptor expression and a concomitant downregulation of GABA receptor expression in BLA glutamatergic neurons have been associated with enhanced exploratory behaviors, validated through in vivo receptor antagonists. These findings unveil the protective role of mild stress exposure during adolescence against adversity, providing novel insights for addressing stressful events.