Involvement of pGluR1, EAAT2 and EAAT3 in offspring depression induced by prenatal stress

It is widely known that prenatal stress (PS) exposure causes depression-like behaviour to offspring, as well as maladaptive responses including neurobiological and physiological changes. However, the underlying mechanism of PS induced juvenile-onset depression remains largely unravelled. The inadequacies of monoamine deficiency hypothesis, the emerging evidence of altered glutamate neurotransmission in mood disorders, as well as our previous studies inspired us to assess the potential role of glutamatergic system in the pathogenesis of juvenile depression. In this research, we examined the expression of phosphorylated GluR1 subunit of ionotropic receptor alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), the Na+-dependent glutamate transporters excitatory amino acid transporter 2 (EAAT2) and EAAT3 in the hippocampus, striatum and frontal cortex of 1-month-old rat offspring after mid and late PS exposure. Prenatally stressed offspring rats showed significantly prolonged duration of immobility and shortened immobility latency in tail suspension test. We also detected that PS significantly altered the expression of glutamate receptor and glutamate transporters of these depressed rats. In brief, the changes of phosphorylated GluR1 subunit of AMPAR protein level in the hippocampus and frontal cortex, as well as markedly decreased EAAT2 mRNA expression in the hippocampus, striatum and frontal cortex and EAAT3 mRNA expression in the hippocampus of stressed rats were both observed. These results underpinned that glutamate receptors and glutamate transporters might be involved in the progress of depression-like behaviour in juvenile rat offspring induced by PS.