Acute stress-induced changes in hippocampal/prefrontal circuits in rats: effects of antidepressants.

Acute stress inhibits long-term potentiation (LTP) at synapses from the hippocampus to prefrontal cortex in the rat, a model of the dysfunction in the anterior cingulate/orbitofrontal cortices which has been observed in human depression. We demonstrate that the antidepressants tianeptine and, to a lesser extent, fluoxetine, are able to reverse the impairment in LTP, a measure of frontal synaptic plasticity, caused by stress on an elevated platform. LTP was induced by stimulation of hippocampal outflow. Beneficial effects on neuronal plasticity, defined as a reversal of the effects of stress in this paradigm, can be considered as a new animal model for the impact of stress on hippocampal/frontal circuits, a key target in psychiatric diseases.