Corticosterone regulates pERK1/2 map kinase in a chronic depression model.

Neurotransmitter- or neurotrophin-regulated intracellular signaling in the hippocampus is hypothesized to contribute to depression and antidepressant (ADT) efficacy. Extracellular signal-regulated kinase 1/2 (ERK1/2) is downstream of several receptor types and regulates transcriptional activity of many targets; ERK1/2 may thereby influence mood and affect. Using a novel, ADT-sensitive depression model in mice, we show that prior corticosterone exposure decreases motivated behavior, sucrose consumption, and pERK1/2 in the dentate gyrus, but not in CA1/CA3. Notably, prefrontal cortical targets were also regulated. Our data suggest ADTs restore hippocampal pERK1/2 after stress-related insult, and potentially reveal a novel role for prefrontal neurotrophins in depressive-like symptomology.