GAD1 and major depressive disorder: For example, hippocampal increases in expression of mitogen-activated proteinkinase phosphatase-1, a negative regulator of mitogen-activated protein kinaseintracellular signaling,53 or altered expression of synaptic proteins or GATA1, a transcription factorinvolved in synaptogenesis.54 Combined with evidence of decreased GAD67 expression in the PFC ofCUS-exposed animals in this study, comparable to pathology in humans,14 these changes further support CUS as a valid rodent model to explore thepathogenic and pathophysiological processes associated with depression.